WO2011040479A1 - Optical unit, projection image display device, and diffusion optical element - Google Patents

Abstract

Disclosed is a projection image display device which is provided with: a light source (110) which emits light having coherency; a light modulation element (500), which modules the light emitted from the light source; and a projection unit (150) which projects, to a projection surface, the light emitted from the light modulation element. The projection image display device is also provided with a speckle noise reducing element (600) provided between the light source and the light modulation element, and a control unit which controls first mode and second mode. The control unit controls the speckle noise reducing element such that speckles are reduced in the first mode compared with those in the second mode.

Description

Optical unit, projection display apparatus, and diffusion optical element

The present invention relates to an optical unit including a light source that emits coherent light, a projection display apparatus, and a diffusion optical element that diffuses coherent light.

2. Description of the Related Art Conventionally, a projection display apparatus having a light source, a light modulation element that modulates light emitted from the light source, and a projection unit that projects light emitted from the light modulation element onto a projection surface is known.

In recent years, an attempt has been made to use a laser light source as a light source of a projection display apparatus mainly for increasing the brightness of image light.

Here, since the laser light emitted from the laser light source has coherence, speckle noise becomes a problem. Speckle noise is noise generated when image light emitted from the projection unit is scattered on the projection surface and the scattered light interferes. As a technique for reducing speckle noise, the following technique has been proposed.

The first method is a method of diffusing laser light by a disk-shaped diffusion plate that rotates around a rotation axis parallel to the traveling direction of the laser light (for example, Patent Document 1). The second method is a method of diffusing laser light with two diffusion plates (for example, Patent Document 2).

Incidentally, in the first method and the second method, a diffusing plate is used to reduce speckle noise. However, when the laser light is diffused by the diffusing plate, the brightness of the light projected on the projection surface is lowered. That is, the effect of removing speckle noise and the luminance of the image displayed on the projection surface have a trade-off relationship.

JP 2008-122823 A JP 2008-134269 A

A projection display apparatus according to a first feature includes a light source (light source unit 110) that emits coherent light, a light modulation element (DMD 500) that modulates light emitted from the light source, and the light. A projection unit (projection unit 150) that projects the light emitted from the modulation element onto the projection surface. The projection display apparatus includes a speckle noise reduction element provided between the light source and the light modulation element, and a control unit (control unit 800) that controls the first mode and the second mode. The control unit controls the speckle noise reduction element so that speckle is reduced in the first mode than in the second mode.

A projection display apparatus according to a second feature includes a light source (light source unit 110) that emits coherent light, a light modulation element (DMD 500) that modulates light emitted from the light source, and the light. A projection unit (projection unit 150) that projects the light emitted from the modulation element onto the projection surface. The projection display apparatus is provided between the light source and the light modulation element, and diffuses light emitted from the light source and diffuses light emitted from the light source (diffusion optical element). And an optical element 600) and a control unit (control unit 800) for controlling the first mode and the second mode. The control unit controls the diffusing optical element so as to diffuse light emitted from the light source in the first mode with a higher diffusivity than in the second mode.

In the second feature, the diffusion optical element has a plurality of diffusion surfaces in the traveling direction of the light emitted from the light source. The control unit controls the diffusion optical element so that the plurality of diffusion surfaces operate with different operation patterns.

In the second feature, the diffusion optical element includes a first rotating body that rotates about a first rotation axis, a second rotating body that rotates about a second rotation axis that is parallel to the first rotation axis, and A strip-shaped diffusion sheet wound in an endless loop around the first rotating body and the second rotating body. The strip-shaped diffusion sheet constitutes two diffusion surfaces in the traveling direction of the light emitted from the light source. The controller controls the diffusing optical element such that two diffusing surfaces move in opposite directions with the rotation of the first rotating body and the second rotating body.

In the second feature, the control unit controls the diffusion optical element so that when one diffusion surface of the plurality of diffusion surfaces stops, the other diffusion surface moves.

In the second feature, the diffusing optical element includes a first diffusing plate and a second diffusing plate. The control unit controls the diffusion optical element so that the first diffusion plate and the second diffusion plate vibrate along different directions.

In the second feature, the diffusion optical element has a plurality of diffusion regions having different diffusivities. In the second mode, the control unit controls the diffusing optical element so as to diffuse light emitted from the light source by using a diffusion region having a lower diffusivity than the diffusion region used in the first mode. To do.

The diffusing optical element according to the third feature diffuses coherent light and transmits coherent light. The diffusion optical element includes: a first rotating body that rotates about a first rotating shaft; a second rotating body that rotates about a second rotating shaft that is parallel to the first rotating shaft; the first rotating body; A belt-shaped diffusion sheet wound in an endless loop around the second rotating body. The strip-shaped diffusion sheet constitutes two diffusion surfaces that move in opposite directions.

A projection display apparatus according to a fourth feature includes a light source (light source unit 110) that emits coherent light, a light modulation element (DMD 500) that modulates light emitted from the light source, and the light. A projection unit (projection unit 150) that projects light emitted from the modulation element onto a projection plane, and relays the light emitted from the light source so that the light emitted from the light source is applied to the light modulation element. A relay optical system (for example, lens 21W, lens 23, lens 40). The projection display apparatus includes a uniformizing optical element (for example, a diffusing optical element 600) that uniformizes the spatial distribution of the light intensity on the exit pupil plane of the projection unit.

In the fourth feature, the uniformizing optical element is provided between the light source and the light modulation element, and diffuses light emitted from the light source and transmits light emitted from the light source. A diffusing optical element. The diffusing optical element includes a central region including an optical axis center emitted from the light source, and a peripheral region provided around the central region. The diffusivity of the central region is greater than the diffusivity of the peripheral region.

In the fourth feature, the projection display apparatus further includes a control unit (control unit 800) for controlling the uniformizing optical element so as to operate in a predetermined operation pattern.

The diffusing optical element according to the fifth feature has a diffusing region that diffuses coherent light and diffuses coherent light. The diffusion region includes a central region including an optical axis center of coherent light and a peripheral region provided around the central region. The diffusivity of the central region is greater than the diffusivity of the peripheral region.

The optical unit according to the sixth feature (for example, speckle noise reduction element 20R) includes a pair of lens arrays (incident side microlens array 310 and exit side microlens array 312) and vibration that vibrates the pair of lens arrays. And providing means.

Here, the vibration may be a movement that periodically changes within a predetermined range, and includes a linear movement, rotation, swinging, and the like.

According to this aspect, speckle noise can be reduced, and an increase in the divergence angle of incident light can be suppressed.

In the sixth feature, the pair of lens arrays includes a first lens array having a focal length f (incident side microlens array 310), a second lens array having a focal length f ′, and an outgoing side microlens array. 312), and when a medium having an absolute refractive index n is interposed between the first lens array and the second lens array, the first lens array and the second lens array , Approximately (f + f ′) / n.

That is, if the first lens array and the second lens array have the same focal length f, the distance between the first lens array and the second lens array may be approximately 2f / n. If it is air, it is sufficient to have an interval of approximately f + f ′.

A projection display apparatus (projection display apparatus 100) according to the seventh feature includes a light source unit (light source unit 110) configured by a coherent light source and an optical axis of light emitted from the light source unit. An optical unit that vibrates in a substantially orthogonal direction (for example, speckle noise reduction element 20R), a light modulation element (for example, DMD500R) that modulates light emitted from the light source unit, and modulated by the light modulation element A projection unit that projects light (projection unit 150). The optical unit includes a pair of lens arrays (an incident side microlens array 310 and an emission side microlens array 312).

According to the seventh feature, speckle noise related to a projection display apparatus using a coherent light source can be reduced, and light loss due to an increase in light divergence angle can be reduced.

In the seventh feature, when a divergence angle of light incident on the optical unit is θ, a lens array (incident side microlens array 310) arranged at least on the incident side of the pair of lens arrays has tan θ < The lens diameter d and focal length f of each lens (incident side microlens 311) may be set so as to satisfy the condition of d / 4f.

FIG. 1 is a diagram showing a schematic configuration of a projection display apparatus 100 according to the first embodiment. FIG. 2 is a diagram showing a schematic configuration of the projection display apparatus 100 according to the first embodiment. FIG. 3 is a diagram showing an optical configuration of the projection display apparatus 100 according to the first embodiment. FIG. 4 is a diagram illustrating a first configuration example of the diffusing optical element 600 according to the first embodiment. FIG. 5 is a diagram illustrating a second configuration example of the diffusing optical element 600 according to the first embodiment. FIG. 6 is a diagram illustrating a third configuration example of the diffusing optical element 600 according to the first embodiment. FIG. 7 is a block diagram showing the control unit 800 according to the first embodiment. FIG. 8 is a diagram for explaining the external interface 810 according to the first embodiment. FIG. 9 is a diagram for explaining the external interface 810 according to the first embodiment. FIG. 10 is a diagram for explaining the external interface 810 according to the first embodiment. FIG. 11 is a diagram showing a diffusing optical element 600 according to the first modification. FIG. 12 is a view showing a diffusing optical element 600 according to the first modification. FIG. 13 is a view showing a diffusing optical element 600 according to the first modification. FIG. 14 is a diagram showing a diffusing optical element 600 according to the second modification. FIG. 15 is a view showing a diffusing optical element 600 according to the second modification. FIG. 16 is a diagram showing a diffusing optical element 600 according to the second modification. FIG. 17 is a view showing a diffusing optical element 600 according to the third modification. FIG. 18 is a view showing a diffusing optical element 600 according to the third modification. FIG. 19 is a diagram showing a schematic configuration of a projection display apparatus 100 according to the second embodiment. FIG. 20 is a diagram showing a schematic configuration of a projection display apparatus 100 according to the second embodiment. FIG. 21 is a diagram showing an optical configuration of the projection display apparatus 100 according to the second embodiment. FIG. 22 is a diagram illustrating a first configuration example of the diffusing optical element 600 according to the second embodiment. FIG. 23 is a diagram illustrating a second configuration example of the diffusing optical element 600 according to the second embodiment. FIG. 24 is a block diagram showing a control unit 800 according to the second embodiment. FIG. 25 is a diagram for explaining the spatial distribution of light intensity according to the related art. FIG. 26 is a diagram for explaining the spatial distribution of light intensity according to the related art. FIG. 27 is a diagram for explaining the spatial distribution of the light intensity according to the second embodiment. FIG. 28 is a diagram for explaining the spatial distribution of the light intensity according to the second embodiment. FIG. 29 is a perspective view showing a projection display apparatus 100 according to the third embodiment. FIG. 30 is a side view of the projection display apparatus 100 according to the third embodiment. FIG. 31 is a top view of the projection display apparatus 100 according to the third embodiment. FIG. 32 is a diagram illustrating the light source unit 110 according to the third embodiment. FIG. 33 is a diagram showing a color separation / synthesis unit 140 and a projection unit 150 according to the third embodiment. FIG. 34 is a detailed view of the speckle noise reduction element according to the third embodiment. FIG. 35A is an optical path diagram of light passing through the speckle noise reduction element according to the third embodiment. FIG. 35B is an optical path diagram of light that passes when the speckle noise reduction element according to the third embodiment moves upward from FIG. 35A due to vibration. FIG. 35C is an optical path diagram of light that passes when the speckle noise reduction element according to the third embodiment moves below the position in FIG. 35A due to vibration. FIG. 36 is a diagram illustrating the color separation / synthesis unit 140 and the projection unit 150 according to the first modification. FIG. 37 is a side view of the projection display apparatus 100 according to the fourth embodiment.

Next, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings in the following embodiments, the same or similar parts are denoted by the same or similar reference numerals.

However, it should be noted that the drawings are schematic and ratios of dimensions are different from actual ones. Therefore, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[Outline of First Embodiment]
(Configuration of the first embodiment)
The projection display apparatus according to the first embodiment includes a light source that emits coherent light, a light modulation element that modulates light emitted from the light source, and a projection surface that emits light emitted from the light modulation element. A projection unit for projecting to the projector. The projection display apparatus is provided between the light source and the light modulation element, diffuses light emitted from the light source and transmits light emitted from the light source, and a first mode. A control unit for controlling the second mode. The control unit controls the diffusion optical element in the first mode so as to diffuse the light emitted from the light source with a higher diffusivity than in the second mode.

In the first embodiment, the control unit controls the diffusion optical element in the first mode so as to diffuse the light emitted from the light source with a higher diffusivity than in the second mode. That is, in the first mode, speckle noise is effectively removed because the degree of diffusion is higher than in the second mode. On the other hand, in the second mode, since the diffusivity is lower than that in the first mode, a decrease in luminance is suppressed. That is, it is possible to appropriately achieve both speckle noise removal and luminance reduction suppression by switching modes.

[First Embodiment]
(Configuration of projection display device)
Hereinafter, the configuration of the projection display apparatus according to the first embodiment will be described with reference to the drawings. FIG. 1 is a perspective view showing a projection display apparatus 100 according to the first embodiment. FIG. 2 is a side view of the projection display apparatus 100 according to the first embodiment.

As shown in FIGS. 1 and 2, the projection display apparatus 100 has a housing 200 and projects an image on the projection plane 300. In the following, a case where the projection display apparatus 100 projects image light onto the projection plane 300 provided on the wall surface will be exemplified (wall surface projection).

The arrangement of the casing 200 in such a case is referred to as a wall surface projection arrangement. Specifically, the projection display apparatus 100 is disposed along a wall surface 420 and a floor surface 410 that is substantially perpendicular to the wall surface 420.

In the first embodiment, a horizontal direction parallel to the projection plane 300 is referred to as a “width direction”. The normal direction of the projection plane 300 is referred to as “depth direction”. A direction orthogonal to both the width direction and the depth direction is referred to as a “height direction”.

The housing 200 has a substantially rectangular parallelepiped shape. The size of the housing 200 in the depth direction and the size of the housing 200 in the height direction are smaller than the size of the housing 200 in the width direction. The size of the casing 200 in the depth direction is substantially equal to the projection distance from the reflection mirror (concave mirror 152 shown in FIG. 2) to the projection plane 300. In the width direction, the size of the casing 200 is substantially equal to the size of the projection plane 300. In the height direction, the size of the housing 200 is determined according to the position where the projection plane 300 is provided.

Specifically, the housing 200 includes a projection surface side wall 210, a front surface side wall 220, a bottom plate 230, a top plate 240, a first side surface side wall 250, and a second side surface side wall 260. .

The projection surface side wall 210 is a plate-like member facing a first arrangement surface (in the first embodiment, a wall surface 420) substantially parallel to the projection surface 300. The front side wall 220 is a plate-like member provided on the opposite side of the projection plane side wall 210. The bottom plate 230 is a plate-like member that faces the floor surface 410. The top plate 240 is a plate-like member provided on the opposite side of the bottom plate 230. The first side wall 250 and the second side wall 260 are plate-like members that form both ends of the housing 200 in the width direction.

The housing 200 accommodates the light source unit 110, the power supply unit 120, the cooling unit 130, the color separation / combination unit 140, and the projection unit 150. The projection surface side sidewall 210 has a projection surface side recess 160A and a projection surface side recess 160B. The front side wall 220 has a front side convex portion 170. The top plate 240 has a top plate recess 180. The first side wall 250 has a cable terminal 190.

The light source unit 110 is a unit composed of a plurality of light sources (solid light sources 111W shown in FIG. 3). Each light source is a semiconductor laser element such as an LD (Laser Diode). In the first embodiment, the plurality of solid light sources 111W emit white light W having coherence. Details of the light source unit 110 will be described later.

The power supply unit 120 is a unit that supplies power to the projection display apparatus 100. For example, the power supply unit 120 supplies power to the light source unit 110 and the cooling unit 130.

The cooling unit 130 is a unit that cools a plurality of light sources provided in the light source unit 110. Specifically, the cooling unit 130 cools each light source by cooling a cooling jacket on which each light source is placed.

The cooling unit 130 is configured to cool the power supply unit 120 and the light modulation element (DMD 500 described later) in addition to each light source.

Color separation / combination unit 140 separates white light W and separates red component light R, green component light G, and blue component light B. Further, the color separation / combination unit 140 recombines the red component light R, the green component light G, and the blue component light B, and emits image light to the projection unit 150. Details of the color separation / synthesis unit 140 will be described later (see FIG. 3).

The projection unit 150 projects the light (image light) emitted from the color separation / synthesis unit 140 onto the projection plane 300. Specifically, the projection unit 150 includes a projection lens group (projection lens group 151 shown in FIG. 3) that projects the light emitted from the color separation / synthesis unit 140 onto the projection plane 300, and the projection lens group. A reflection mirror (concave mirror 152 shown in FIG. 3) that reflects light toward the projection surface 300; Details of the projection unit 150 will be described later.

The projection surface side recess 160A and the projection surface side recess 160B are provided on the projection surface side wall 210 and have a shape that is recessed inside the housing 200. The projection surface side recess 160 </ b> A and the projection surface side recess 160 </ b> B extend to the end of the housing 200. The projection surface side recess 160 </ b> A and the projection surface side recess 160 </ b> B are provided with vent holes that communicate with the inside of the housing 200.

In the first embodiment, the projection surface side recess 160A and the projection surface side recess 160B extend along the width direction of the housing 200. For example, the projection surface side recess 160 </ b> A is provided with an air inlet for allowing air outside the housing 200 to enter the housing 200 as a vent. The projection surface side recess 160 </ b> B is provided with an exhaust port for venting air inside the housing 200 to the outside of the housing 200 as a vent.

The front side convex portion 170 is provided on the front side wall 220 and has a shape protruding to the outside of the housing 200. The front side convex portion 170 is provided at the approximate center of the front side wall 220 in the width direction of the housing 200. A reflection mirror (concave mirror 152 shown in FIG. 3) provided in the projection unit 150 is accommodated in a space formed by the front-side convex portion 170 inside the housing 200.

The top plate recess 180 is provided in the top plate 240 and has a shape that is recessed inside the housing 200. The top plate recess 180 has an inclined surface 181 that goes down toward the projection plane 300 side. The inclined surface 181 has a transmission region that transmits (projects) the light emitted from the projection unit 150 to the projection surface 300 side.

The cable terminal 190 is provided on the first side wall 250 and is a terminal such as a power terminal or a video terminal. The cable terminal 190 may be provided on the second side wall 260.

(Configuration of light source unit, color separation / synthesis unit and projection unit)
Hereinafter, configurations of the light source unit, the color separation / synthesis unit, and the projection unit according to the first embodiment will be described with reference to the drawings. FIG. 3 is a diagram illustrating the light source unit 110, the color separation / synthesis unit 140, and the projection unit 150 according to the first embodiment. The first embodiment exemplifies a projection display apparatus 100 that supports a DLP (Digital Light Processing) method (registered trademark).

As shown in FIG. 3, the light source unit 110 includes a plurality of solid light sources 111W, a plurality of optical fibers 113W, and a bundle portion 114W. As described above, the solid-state light source 111W is a semiconductor laser element such as an LD that emits white light W having coherence. An optical fiber 113W is connected to the solid light source 111W.

The optical fibers 113W connected to each solid light source 111W are bundled by a bundle portion 114W. That is, the light emitted from each solid light source 111W is transmitted by each optical fiber 113W and collected in the bundle portion 114W. The solid light source 111W is placed on a cooling jacket (not shown) for cooling the solid light source 111W.

The color separation / synthesis unit 140 includes a rod integrator 10W, a lens 21W, a lens 23, a mirror 34, and a mirror 35. The color separation / combination unit 140 includes a diffusion optical element 600.

The rod integrator 10W has a light incident surface, a light emitting surface, and a light reflecting side surface provided from the outer periphery of the light incident surface to the outer periphery of the light emitting surface. The rod integrator 10W makes the white light W emitted from the optical fiber 113W bundled by the bundle unit 114W uniform. That is, the rod integrator 10W makes the white light W uniform by reflecting the white light W on the light reflection side surface.

The rod integrator 10W may be a hollow rod having a light reflection side surface constituted by a mirror surface. The rod integrator 10W may be a solid rod made of glass or the like.

The lens 21W is a lens that converts the white light W into a substantially parallel light so that the DMD 500 is irradiated with the white light W. The lens 23 is a lens for substantially imaging the white light W on each DMD 500 while suppressing the expansion of the white light W. The mirror 34 and the mirror 35 reflect the white light W.

The color separation / synthesis unit 140 includes a lens 40, a prism 50, a prism 60, a prism 70, a prism 80, a prism 90, and a plurality of DMDs; Digital Micromirror Device (DMD500R, DMD500G, and DMD500B).

The lens 40 is a lens that makes the white light W substantially parallel so that each color component light is irradiated to each DMD 500.

The prism 50 is made of a translucent member and has a surface 51 and a surface 52. An air gap is provided between the prism 50 (surface 51) and the prism 60 (surface 61), and the angle at which the white light W is incident on the surface 51 (incident angle) is larger than the total reflection angle. The light W is reflected by the surface 51. On the other hand, an air gap is provided between the prism 50 (surface 52) and the prism 70 (surface 71), but the angle at which the white light W enters the surface 52 (incident angle) is smaller than the total reflection angle. The white light W reflected by the surface 51 passes through the surface 52.

The prism 60 is made of a translucent member and has a surface 61.

The prism 70 is made of a translucent member and has a surface 71 and a surface 72. An air gap is provided between the prism 50 (surface 52) and the prism 70 (surface 71), and the blue component light B reflected by the surface 72 and the blue component light B emitted from the DMD 500B are formed on the surface 71. Since the incident angle (incident angle) is larger than the total reflection angle, the blue component light B reflected by the surface 72 and the blue component light B emitted from the DMD 500B are reflected by the surface 71.

The surface 72 is a dichroic mirror surface that transmits the red component light R and the green component light G and reflects the blue component light B. Accordingly, among the light reflected by the surface 51, the red component light R and the green component light G are transmitted through the surface 72, and the blue component light B is reflected by the surface 72. The blue component light B reflected by the surface 71 is reflected by the surface 72.

The prism 80 is made of a translucent member and has a surface 81 and a surface 82. An air gap is provided between the prism 70 (surface 72) and the prism 80 (surface 81). The red component light R transmitted through the surface 81 and reflected by the surface 82 and the red component emitted from the DMD 500R. Since the angle (incident angle) at which the light R again enters the surface 81 is larger than the total reflection angle, the red component light R transmitted through the surface 81 and reflected by the surface 82 and the red component light R emitted from the DMD 500R are Reflected by the surface 81. On the other hand, since the angle (incident angle) at which the red component light R emitted from the DMD 500R and reflected by the surface 81 and then reflected by the surface 82 is incident on the surface 81 again is smaller than the total reflection angle, it is emitted from the DMD 500R. Then, the red component light R reflected by the surface 82 after being reflected by the surface 81 passes through the surface 81.

The surface 82 is a dichroic mirror surface that transmits the green component light G and reflects the red component light R. Accordingly, among the light transmitted through the surface 81, the green component light G is transmitted through the surface 82, and the red component light R is reflected by the surface 82. The red component light R reflected by the surface 81 is reflected by the surface 82. The green component light G emitted from the DMD 500G passes through the surface 82.

Here, the prism 70 separates the combined light including the red component light R and the green component light G and the blue component light B by the surface 72. The prism 80 separates the red component light R and the green component light G by the surface 82. That is, the prism 70 and the prism 80 function as a color separation element that separates each color component light.

In the first embodiment, the cutoff wavelength of the surface 72 of the prism 70 is provided between a wavelength band corresponding to green and a wavelength band corresponding to blue. The cut-off wavelength of the surface 82 of the prism 80 is provided between a wavelength band corresponding to red and a wavelength band corresponding to green.

On the other hand, the prism 70 combines the combined light including the red component light R and the green component light G and the blue component light B with the surface 72. The prism 80 combines the red component light R and the green component light G with the surface 82. That is, the prism 70 and the prism 80 function as a color composition element that synthesizes each color component light.

The prism 90 is made of a translucent member and has a surface 91. The surface 91 is configured to transmit the green component light G. The green component light G incident on the DMD 500G and the green component light G emitted from the DMD 500G pass through the surface 91.

DMD500R, DMD500G, and DMD500B are configured by a plurality of micromirrors, and the plurality of micromirrors are movable. Each minute mirror basically corresponds to one pixel. The DMD 500R switches whether to reflect the red component light R toward the projection unit 150 by changing the angle of each micromirror. Similarly, the DMD 500G and the DMD 500B switch whether to reflect the green component light G and the blue component light B toward the projection unit 150 by changing the angle of each micromirror.

The projection unit 150 includes a projection lens group 151 and a concave mirror 152.

The projection lens group 151 emits light (image light) emitted from the color separation / synthesis unit 140 to the concave mirror 152 side.

The concave mirror 152 reflects light (image light) emitted from the projection lens group 151. The concave mirror 152 condenses the image light and then widens the image light. For example, the concave mirror 152 is an aspherical mirror having a concave surface on the projection lens group 151 side.

The image light collected by the concave mirror 152 passes through a transmission region provided on the inclined surface 181 of the top plate recess 180 provided on the top plate 240. The transmission region provided on the inclined surface 181 is preferably provided in the vicinity of the position where the image light is collected by the concave mirror 152.

The concave mirror 152 is accommodated in the space formed by the front-side convex portion 170 as described above. For example, the concave mirror 152 is preferably fixed inside the front side convex portion 170. In addition, the shape of the inner surface of the front side convex portion 170 is preferably a shape along the concave mirror 152.

Here, in the first embodiment, the color separation / synthesis unit 140 includes the diffusion optical element 600 (speckle noise reduction element) as described above. The diffusing optical element 600 is provided between the light source unit 110 and the DMD 500 on the optical path of the light emitted from the light source unit 110, and is a unit that reduces speckle noise of the light emitted from the light source unit 110. is there. In other words, the diffusion optical element 600 is an optical element that reduces the spatial coherence of the white light W in order to reduce speckle. Specifically, the diffusion optical element 600 diffuses the white light W made uniform by the rod integrator 10W and transmits the white light W. For example, the configuration shown below can be considered as the configuration of the diffusing optical element 600.

(First configuration example)
In the first configuration example, as illustrated in FIG. 4, the diffusing optical element 600 includes a driving device 610 and a diffusing plate 620.

The driving device 610 is connected to the diffusion plate 620 by an arm 611 and controls the diffusion plate 620 by driving the arm 611.

The diffusion plate 620 is disposed between the light source unit 110 and the DMD 500 on the optical path of the light emitted from the light source unit 110. The diffusion plate 620 diffuses the light emitted from the light source unit 110 and transmits the light emitted from the light source unit 110.

Specifically, the diffusion plate 620 includes a plurality of regions (diffusion region 621, diffusion region 622, and diffusion region 623) having different diffusivities. In the first embodiment, the diffusion degree of the diffusion region 621 is higher than that of the diffusion region 622, and the diffusion degree of the diffusion region 622 is higher than that of the diffusion region 623.

Here, in the first configuration example, the driving device 610 switches the region irradiated with the light emitted from the rod integrator 10W among the diffusion regions 621 to 623 by driving the arm 611. Further, the driving device 610 vibrates the region irradiated with the light emitted from the rod integrator 10 </ b> W by driving the arm 611.

(Second configuration example)
In the second configuration example, as illustrated in FIG. 5, the diffusion optical element 600 includes a driving device 610 and a diffusion plate 620 as in the first configuration example.

Here, in the second configuration example, the driving device 610 is connected to the rotating body 612 and drives the rotating body 612. The driving device 610 switches the region irradiated with the light emitted from the rod integrator 10W among the diffusion regions 621 to 623 by driving the rotating body 612. Similarly to the first configuration example, the driving device 610 vibrates the region irradiated with the light emitted from the rod integrator 10 </ b> W by driving the arm 611.

(Third configuration example)
In the third configuration example, as shown in FIG. 6, a speckle reduction unit 600A is provided on the light incident side of the rod integrator 10W, and a speckle reduction unit 600B is provided on the light emission side of the rod integrator 10W. The configurations of the speckle reduction unit 600A and the speckle reduction unit 600B are the same as those of the diffusion optical element 600.

Further, the diffusion plate 620A provided in the speckle reduction unit 600A is configured to be disposed on the optical path incident on the rod integrator 10W. The diffusion plate 620B provided in the speckle reduction unit 600B is configured to be disposed on the optical path of the light emitted from the rod integrator 10W.

In the third configuration example, the diffusion plate 620A and the diffusion plate 620B may be configured only by a region having a single diffusion degree. However, the diffusion degree of the diffusion plate 620A may be different from the diffusion degree of the diffusion plate 620B.

For example, in the third configuration example, the driving device 610B provided in the speckle reduction unit 600B can drive the arm 611B so that the diffusion plate 620B is disposed in the optical path of the light emitted from the rod integrator 10W. Further, the driving device 610B can drive the arm 611B so as to remove the diffusion plate 620B from the optical path of the light emitted from the rod integrator 10W.

Note that the driving device 610A provided in the speckle reduction unit 600A may be able to drive the arm 611A so that the diffusion plate 620A is disposed in the optical path of the light emitted from the rod integrator 10W. The driving device 610A may be capable of driving the arm 611A so as to remove the diffusion plate 620A from the optical path of the light emitted from the rod integrator 10W.

(Configuration of control unit)
The control unit according to the first embodiment will be described below with reference to the drawings. FIG. 7 is a block diagram showing the control unit 800 according to the first embodiment. The control unit 800 is provided in the projection display apparatus 100 and controls the projection display apparatus 100.

The control unit 800 converts the video input signal into a video output signal. The video input signal includes a red input signal R _in , a green input signal G _in, and a blue input signal B _in . The video output signal includes a red output signal _Rout , a green output signal _Gout, and a blue output signal _Bout . The video input signal and the video output signal are signals input for each of a plurality of pixels constituting one frame.

In the first embodiment, the control unit 800 controls a plurality of modes (at least the first mode and the second mode) having different diffusivities of light emitted from the light source unit 110. Here, the higher the diffusivity, the higher the effect of removing speckle noise. On the other hand, as the diffusivity is higher, the effective light guided to the DMD 500 is decreased, so that the luminance of the image displayed on the projection plane 300 is decreased. That is, the effect of removing speckle noise and the luminance of the image displayed on the projection plane 300 have a trade-off relationship.

In the first embodiment, the control unit 800 controls whether priority is given to removal of speckle noise or video brightness by controlling a plurality of modes having different diffusion degrees of light emitted from the light source unit 110. To do.

As shown in FIG. 7, the control unit 800 includes an external interface 810 and a mode control unit 820.

The external interface 810 is connected to the operation unit 910 and acquires an operation signal from the operation unit 910. Note that the operation unit 910 may be provided in the projection display apparatus 100 (housing 200), or may be provided in a remote controller.

Here, for example, as shown in FIG. 8, the operation signal is a signal indicating a level giving priority to the luminance of the video. In FIG. 8, three levels are illustrated, and when level 1 is selected, the luminance of the video is given the highest priority. That is, when level 1 is selected, the mode is selected so that the diffusion degree of the light emitted from the light source unit 110 is the lowest. On the other hand, when level 3 is selected, removal of speckle noise has the highest priority. That is, when level 3 is selected, the mode is selected so that the diffusion degree of the light emitted from the light source unit 110 is the highest.

Alternatively, the operation signal is a signal indicating the distance between the projection plane 300 (screen) and the viewer, for example, as shown in FIG. Here, the greater the distance between the projection plane 300 (screen) and the viewer, the less speckle noise is observed. Therefore, the mode in which the diffusion degree of the light emitted from the light source unit 110 is lower is selected as the distance between the projection plane 300 (screen) and the viewer is larger.

The external interface 810 is connected to the imaging device 920A and the imaging device 920B, and acquires a captured image from the imaging device 920A and the imaging device 920B. Here, as shown in FIG. 10, the imaging device 920 </ b> A and the imaging device 920 </ b> B are provided in the projection display apparatus 100 (housing 200), and are opposite to the projection plane 300 with respect to the projection display apparatus 100. Image the side. That is, the imaging device 920A and the imaging device 920B capture an image of the viewer.

Note that the distance between the projection plane 300 (screen) and the viewer can be specified by the captured images acquired from the imaging device 920A and the imaging device 920B.

The mode control unit 820 controls a plurality of modes with different degrees of diffusion of light emitted from the light source unit 110. Specifically, first, the mode control unit 820 selects a mode from a plurality of modes based on information acquired by the external interface 810.

For example, when an operation signal indicating a level giving priority to video luminance is acquired by the external interface 810, the mode control unit 820 selects any mode from a plurality of modes based on the level giving priority to luminance. To do. Alternatively, when the operation signal indicating the distance between the projection plane 300 (screen) and the viewer is acquired by the external interface 810, the mode control unit 820 displays the distance between the projection plane 300 (screen) and the viewer. Any mode is selected from a plurality of modes based on the distance. Alternatively, when the captured image is acquired by the external interface 810, the mode control unit 820 specifies the distance between the projection plane 300 (screen) and the viewer, and the projection plane 300 (screen) and the viewer. Any mode is selected from a plurality of modes based on the distance between the two modes.

Second, the mode control unit 820 controls the driving device 610 provided in the diffusing optical element 600 based on the selected mode.

For example, when there are three types of a plurality of modes and the diffusing optical element 600 is the first configuration example shown in FIG. 4, the mode control unit 820 selects the diffusion region 621 to the diffusion region based on the selected mode. The drive device 610 (arm 611) is controlled so as to switch the region irradiated with the light emitted from the rod integrator 10W. For example, the drive device 610 (arm 611) is controlled so that the light emitted from the rod integrator 10W is irradiated onto the diffusion region 621 when the mode in which speckle noise removal is given the highest priority is selected. On the other hand, the drive device 610 (arm 611) is controlled so that the light emitted from the rod integrator 10W is irradiated onto the diffusion region 623 when the mode in which the luminance of the video image has the highest priority is selected.

Similarly, when there are three types of the plurality of modes and the diffusing optical element 600 is the second configuration example shown in FIG. 5, the mode control unit 820 performs diffusion regions 621 to diffusing based on the selected mode. The drive device 610 (rotating body 612) is controlled so as to switch the region irradiated with the light emitted from the rod integrator 10W in the region 623.

Alternatively, when there are two types of the plurality of modes and the diffusion optical element 600 is the third example shown in FIG. 6, the mode control unit 820 transmits the light emitted from the rod integrator 10W. Control the number of sheets. Specifically, when a mode in which speckle noise removal is prioritized is selected, the mode control unit 820 drives the drive device 610 (arm 611B) so as to remove the diffuser plate 620B from the light emitted from the rod integrator 10W. To control. On the other hand, when the mode in which the luminance of the image is prioritized is selected, the mode control unit 820 causes the driving device 610 (arms) so that the diffusion plate 620B is disposed on the optical path of the light emitted from the rod integrator 10W. 611B).

Third, the mode control unit 820 controls the driving device 610 (arm 611) so that the diffusion plate (diffusion region) disposed on the optical path of the light emitted from the rod integrator 10W operates in a predetermined operation pattern. .

(Action and effect)
In the first embodiment, the control unit 800 has a higher diffusivity in the first mode (for example, a mode in which speckle noise removal is prioritized) than in the second mode (for example, a mode in which video luminance is prioritized). Thus, the diffusion optical element 600 is controlled so as to diffuse the light emitted from the light source unit 110. That is, in the first mode, speckle noise is effectively removed because the degree of diffusion is higher than in the second mode. On the other hand, in the second mode, since the diffusivity is lower than that in the first mode, a decrease in luminance is suppressed. That is, it is possible to appropriately achieve both speckle noise removal and luminance reduction suppression by switching modes.

[Modification 1]
Hereinafter, Modification Example 1 of the first embodiment will be described with reference to the drawings. In the following, differences from the first embodiment will be mainly described.

Specifically, in the first modification, the configuration of the diffusing optical element 600 is different from that in the first embodiment.

(Configuration of diffusion optical element)
Hereinafter, the configuration of the diffusing optical element according to the modification example 1 will be described with reference to the drawings. 11 and 12 are diagrams showing a diffusing optical element 600 according to the first modification.

As shown in FIGS. 11 and 12, the diffusing optical element 600 includes a pair of rotating bodies (rotating body 651 and rotating body 652), and a belt-like diffusion wound around the rotating body 651 and the rotating body 652 in an endless loop shape. A sheet 653.

The rotating body 651 can rotate around the rotation axis S1. The rotating body 652 can rotate around a rotation axis S2 substantially parallel to the rotation axis S1. A driving device (not shown) is connected to either the rotating shaft S1 or the rotating shaft S2. For example, the driving device is a motor, and the motor rotates the rotation shaft S1. Here, when the rotating body 651 rotates, the rotational force of the rotating body 651 is transmitted to the rotating body 652 through the belt-shaped diffusion sheet 653. As a result, the rotating body 652 also rotates. That is, both the rotating body 651 and the rotating body 652 can be rotated by driving one motor without using two motors.

Each of the rotator 651 and the rotator 652 has a columnar shape and has substantially the same shape. Between the rotator 651 and the rotator 652, an interval is provided which is approximately the same as the diameter of the light beam emitted from the light exit surface of the rod integrator 10 </ b> W.

The strip-shaped diffusion sheet 653 is formed of a light transmissive member. The band-shaped diffusion sheet 653 is engraved with minute irregularities. The strip-shaped diffusion sheet 653 diffuses the white light W emitted from the rod integrator 10 </ b> W and transmits the white light W. The strip-shaped diffusion sheet 653 has a width approximately equal to the diameter of the light beam emitted from the rod integrator 10W.

The strip-shaped diffusion sheet 653 constitutes a diffusion surface F1 and a diffusion surface F2 that are spaced apart in the traveling direction of the white light W. The size of each of the diffusing surface F1 and the diffusing surface F2 is approximately the same as the diameter of the light beam. Each of the diffusing surface F1 and the diffusing surface F2 continuously moves as the rotating body 651 and the rotating body 652 rotate. The moving direction of the diffusing surface F1 is opposite to the moving direction of the diffusing surface F2.

In the first modification, the diffusion surface F1 is a first diffusion surface that continuously moves in a predetermined direction. The diffusion surface F2 is a second diffusion surface that continuously moves in a direction opposite to a predetermined direction (movement direction of the diffusion surface F1).

The white light W emitted from the rod integrator 10W first passes through the diffusion surface F1, and then passes through the diffusion surface F2. When the white light W passes through the diffusion surface F1, the white light W is diffused by the diffusion surface F1. When the white light W passes through the diffusion surface F2, the white light W is diffused by the diffusion surface F2.

In addition, the direction of the rotation axis S1 and the rotation axis S2 may be substantially perpendicular to the optical axis of the rod integrator 10W. That is, the diffusing surface F1 and the diffusing surface F2 may be substantially perpendicular to the optical axis of the rod integrator 10W.

For example, as shown in FIG. 12A, the diffusing optical element 600 may be arranged such that the orientations of the rotation axis S1 and the rotation axis S2 are in the height direction of the projection display apparatus 100. In the case shown in FIG. 12A, the diffusion surface F <b> 1 and the diffusion surface F <b> 2 move along the height direction of the projection display apparatus 100.

Alternatively, as shown in FIG. 12B, the diffusing optical element 600 may be arranged so that the directions of the rotation axis S <b> 1 and the rotation axis S <b> 2 are the width direction of the projection display apparatus 100. In the case shown in FIG. 12A, the diffusion surface F <b> 1 and the diffusion surface F <b> 2 move along the width direction of the projection display apparatus 100.

(Action and effect)
In the first modification, the white light W is diffused by the diffusion surface F1 and the diffusion surface F2, and the diffusion surface F1 and the diffusion surface F2 move continuously. In other words, the diffusion surface F1 and the diffusion surface F2 always move without the diffusion surface F1 and the diffusion surface F2 being stationary. Therefore, the effect of reducing speckle noise can always be maintained.

In the first modification, the diffusion surface F1 and the diffusion surface F2 are configured by the belt-like diffusion sheet 653 wound around the rotating body 651 and the rotating body 652 in an endless loop shape. Therefore, the size of the diffusing optical element 600 can be made approximately the same as the size of the light beam emitted from the rod integrator 10W. Therefore, the diffusing optical element 600 can be reduced in size, and the projection display apparatus 100 can be reduced in size.

In the first modification, the rotating body 651 and the rotating body 652 are rotated by one motor, so that power saving can be achieved.

In the first modification, the diffusion optical element 600 is provided on the light exit side of the rod integrator 10W. Therefore, compared with the case where the diffusion optical element 600 is provided on the light incident side of the rod integrator 10W, a decrease in light utilization efficiency can be suppressed. Specifically, in the case where the diffusion optical element 600 is provided on the light incident side of the rod integrator 10W, a part of the light beam diffused by the diffusion optical element 600 may not enter the rod integrator 10W.

However, as shown in FIG. 13, a diffusion optical element 600 may be provided on the light incident side of the rod integrator 10W. In such a case, the size of the diffusing surface F1 and the diffusing surface F2 is smaller than the light incident surface of the rod integrator 10W by the strip-shaped diffusing sheet 653 wound around the rotating body 651 and the rotating body 652 in an endless loop shape. Is preferred.

Therefore, in the case shown in FIG. 13, the diffusing optical element 600 can be made smaller than the case where the diffusing optical element 600 is provided on the light exit side of the rod integrator 10W.

[Modification 2]
Hereinafter, Modification Example 2 of the first embodiment will be described with reference to the drawings. In the following, differences from the first embodiment will be mainly described.

Specifically, in the second modification, the configuration of the diffusing optical element 600 is different from that in the first embodiment.

(Configuration of diffusion optical element)
Hereinafter, the configuration of the diffusing optical element according to the modification example 1 will be described with reference to the drawings. FIG. 14 is a diagram showing a diffusing optical element 600 according to the second modification.

As shown in FIG. 14, the diffusing optical element 600 includes a plurality of diffusing plates (a diffusing plate 661 and a diffusing plate 662). The diffusion plate 661 and the diffusion plate 662 are disposed on the light exit side of the rod integrator 10W.

In the first modification, the diffusion plate 661 is a first diffusion plate that vibrates along a predetermined direction. The diffusion plate 662 vibrates in a direction different from that of the diffusion plate 661. That is, the control unit 800 controls the diffusion optical element 600 so that the diffusion plate 661 and the diffusion plate 662 vibrate along different directions.

The diffusing plate 661 and the diffusing plate 662 are formed of a light-transmitting member and have minute unevenness. The diffusing plate 661 and the diffusing plate 662 diffuse the white light W emitted from the rod integrator 10 </ b> W and transmit the white light W.

Here, the control unit 800 controls the diffusion optical element 600 so that when one of the diffusion plates 661 and 662 stops, the other diffusion plate moves.

For example, when the vibration phase of the diffusion plate 661 (diffusion surface F1) is φ and the vibration phase of the diffusion plate 662 (diffusion surface F2) is φ ′, the control unit 800 satisfies the relationship of φ ′ ≠ φ + nπ. Thus, the diffusion optical element 600 is controlled.

It should be noted that the vertical and horizontal sizes of the diffusion plate 661 and the diffusion plate 662 may be equal to or larger than the light output surface (the size of the light beam emitted from the light output surface) of the rod integrator 10W. FIG. 14 illustrates a case where the vertical and horizontal sizes of the diffusion plate 661 and the diffusion plate 662 are approximately the same as the size of the lens 21W.

Note that, as shown in FIGS. 15A and 15B, the vibration directions of the diffusion plate 661 and the diffusion plate 662 may be the same. For example, the vibration directions of the diffusion plate 661 and the diffusion plate 662 may be a direction (D1 direction) perpendicular to the optical axis w of the rod integrator 10W, as shown in FIG. Alternatively, the vibration directions of the diffusion plate 661 and the diffusion plate 662 may be the same direction (D2 direction) as the optical axis w of the rod integrator 10W, as shown in FIG.

Further, as shown in FIGS. 16A and 16B, the vibration directions of the diffusion plate 661 and the diffusion plate 662 may be different. For example, as shown in FIG. 16A, the vibration direction of the diffusion plate 661 may be the D3 direction, and the vibration direction of the diffusion plate 662 may be the D1 direction. Alternatively, as shown in FIG. 16B, the vibration direction of the diffusion plate 661 may be the D1 direction, and the vibration direction of the diffusion plate 662 may be the D2 direction.

(Action and effect)
In the modified example 2, the white light W is diffused by the diffusion plate 661 (diffusion surface F1) and the diffusion plate 662 (diffusion surface F2), and among the diffusion plate 661 (diffusion surface F1) and the diffusion plate 662 (diffusion surface F2), At least one of them always moves. Therefore, the effect of reducing speckle noise can always be maintained.

[Modification 3]
Hereinafter, Modification Example 3 of the first embodiment will be described with reference to the drawings. In the following, differences from the second modification will be mainly described. Specifically, in the third modification, the arrangement of the diffusion plate 661 and the diffusion plate 662 is different.

For example, as shown in FIG. 17, a diffusion plate 661 and a diffusion plate 662 may be disposed on the light incident side of the rod integrator 10W. Alternatively, as illustrated in FIG. 18, the diffusion plate 661 may be disposed on the light incident side of the rod integrator 10 </ b> W, and the diffusion plate 662 may be disposed on the light emission side of the rod integrator 10 </ b> W.

[Outline of Second Embodiment]
(Problem of the second embodiment)
The projection display apparatus has a relay optical system and a projection unit, and the aperture of the relay optical system and the aperture (exit pupil) of the projection unit have a conjugate relationship.

Here, on the aperture plane of the relay optical system and the aperture plane (exit pupil plane) of the projection unit, the spatial distribution of the light intensity is a Gaussian distribution reflecting the angular distribution of the light emitted from the laser light source.

Therefore, considering the light flux from the aperture plane (exit pupil plane) of the projection unit to one point on the projection plane (for example, the center point of the projection plane), the projection plane starts from the peripheral area of the aperture plane (exit pupil plane) of the projection unit. The intensity of light reaching one point is smaller than the intensity of light reaching one point on the projection plane from the central area of the aperture plane (exit pupil plane) of the projection unit.

In this way, since the intensity of light from the aperture plane (exit pupil plane) of the projection unit to one point on the projection plane does not have a uniform angular distribution, the speckle noise reduction effect due to angle superposition is not fully exhibited, Speckle noise is observed.

(Configuration of Second Embodiment)
A projection display apparatus according to the second embodiment includes a light source that emits coherent light, a light modulation element that modulates light emitted from the light source, and a projection surface that emits light emitted from the light modulation element. And a relay optical system that relays the light emitted from the light source so that the light emitted from the light source is irradiated onto the light modulation element. The projection display apparatus includes a uniformizing optical element that uniformizes the spatial distribution of light intensity on the exit pupil plane of the projection unit.

In the second embodiment, the uniformizing optical element uniformizes the spatial distribution of light intensity on the exit pupil plane of the projection unit. Accordingly, since the intensity of light from the aperture plane (exit pupil plane) of the projection unit to one point on the projection plane has a uniform angular distribution, the speckle noise reduction effect due to angle superposition is sufficiently exerted, and speckle noise is reduced. It can be effectively removed.

[Second Embodiment]
(Configuration of projection display device)
Hereinafter, the configuration of the projection display apparatus according to the second embodiment will be described with reference to the drawings. FIG. 19 is a perspective view showing a projection display apparatus 100 according to the second embodiment. FIG. 20 is a side view of the projection display apparatus 100 according to the second embodiment.

As shown in FIGS. 19 and 20, the projection display apparatus 100 has a casing 200 and projects an image on the projection plane 300. In the following, a case where the projection display apparatus 100 projects image light onto the projection plane 300 provided on the wall surface will be exemplified (wall surface projection).

The arrangement of the casing 200 in such a case is referred to as a wall surface projection arrangement. Specifically, the projection display apparatus 100 is disposed along a wall surface 420 and a floor surface 410 that is substantially perpendicular to the wall surface 420.

In the second embodiment, a horizontal direction parallel to the projection plane 300 is referred to as a “width direction”. The normal direction of the projection plane 300 is referred to as “depth direction”. A direction orthogonal to both the width direction and the depth direction is referred to as a “height direction”.

The housing 200 has a substantially rectangular parallelepiped shape. The size of the housing 200 in the depth direction and the size of the housing 200 in the height direction are smaller than the size of the housing 200 in the width direction. The size of the casing 200 in the depth direction is substantially equal to the projection distance from the reflection mirror (concave mirror 152 shown in FIG. 20) to the projection plane 300. In the width direction, the size of the casing 200 is substantially equal to the size of the projection plane 300. In the height direction, the size of the housing 200 is determined according to the position where the projection plane 300 is provided.

Specifically, the housing 200 includes a projection surface side wall 210, a front surface side wall 220, a bottom plate 230, a top plate 240, a first side surface side wall 250, and a second side surface side wall 260. .

The projection surface side wall 210 is a plate-like member that faces a first arrangement surface (in the second embodiment, a wall surface 420) substantially parallel to the projection surface 300. The front side wall 220 is a plate-like member provided on the opposite side of the projection plane side wall 210. The bottom plate 230 is a plate-like member that faces the floor surface 410. The top plate 240 is a plate-like member provided on the opposite side of the bottom plate 230. The first side wall 250 and the second side wall 260 are plate-like members that form both ends of the housing 200 in the width direction.

The housing 200 accommodates the light source unit 110, the power supply unit 120, the cooling unit 130, the color separation / combination unit 140, and the projection unit 150. The projection surface side sidewall 210 has a projection surface side recess 160A and a projection surface side recess 160B. The front side wall 220 has a front side convex portion 170. The top plate 240 has a top plate recess 180. The first side wall 250 has a cable terminal 190.

The light source unit 110 is a unit composed of a plurality of light sources (solid light source 111W shown in FIG. 21). Each light source is a semiconductor laser element such as an LD (Laser Diode). In the second embodiment, the plurality of solid light sources 111W emit white light W having coherence. Details of the light source unit 110 will be described later.

The power supply unit 120 is a unit that supplies power to the projection display apparatus 100. For example, the power supply unit 120 supplies power to the light source unit 110 and the cooling unit 130.

The cooling unit 130 is a unit that cools a plurality of light sources provided in the light source unit 110. Specifically, the cooling unit 130 cools each light source by cooling a cooling jacket on which each light source is placed.

The cooling unit 130 is configured to cool the power supply unit 120 and the light modulation element (DMD 500 described later) in addition to each light source.

Color separation / combination unit 140 separates white light W and separates red component light R, green component light G, and blue component light B. Further, the color separation / combination unit 140 recombines the red component light R, the green component light G, and the blue component light B, and emits image light to the projection unit 150. Details of the color separation / synthesis unit 140 will be described later (see FIG. 21).

The projection unit 150 projects the light (image light) emitted from the color separation / synthesis unit 140 onto the projection plane 300. Specifically, the projection unit 150 projects the light emitted from the color separation / synthesis unit 140 onto the projection plane 300 (projection lens group 151 shown in FIG. 21) and the projection lens group. A reflecting mirror (concave mirror 152 shown in FIG. 21) that reflects light toward the projection plane 300; Details of the projection unit 150 will be described later.

The projection surface side recess 160A and the projection surface side recess 160B are provided on the projection surface side wall 210 and have a shape that is recessed inside the housing 200. The projection surface side recess 160 </ b> A and the projection surface side recess 160 </ b> B extend to the end of the housing 200. The projection surface side recess 160 </ b> A and the projection surface side recess 160 </ b> B are provided with vent holes that communicate with the inside of the housing 200.

In the second embodiment, the projection surface side recess 160A and the projection surface side recess 160B extend along the width direction of the housing 200. For example, the projection surface side recess 160 </ b> A is provided with an air inlet for allowing air outside the housing 200 to enter the housing 200 as a vent. The projection surface side recess 160 </ b> B is provided with an exhaust port for venting air inside the housing 200 to the outside of the housing 200 as a vent.

The front side convex portion 170 is provided on the front side wall 220 and has a shape protruding to the outside of the housing 200. The front side convex portion 170 is provided at the approximate center of the front side wall 220 in the width direction of the housing 200. A reflection mirror (concave mirror 152 shown in FIG. 21) provided in the projection unit 150 is accommodated in a space formed by the front side convex portion 170 inside the housing 200.

The top plate recess 180 is provided in the top plate 240 and has a shape that is recessed inside the housing 200. The top plate recess 180 has an inclined surface 181 that goes down toward the projection plane 300 side. The inclined surface 181 has a transmission region that transmits (projects) the light emitted from the projection unit 150 to the projection surface 300 side.

The cable terminal 190 is provided on the first side wall 250 and is a terminal such as a power terminal or a video terminal. The cable terminal 190 may be provided on the second side wall 260.

(Configuration of light source unit, color separation / synthesis unit and projection unit)
Hereinafter, configurations of the light source unit, the color separation / synthesis unit, and the projection unit according to the second embodiment will be described with reference to the drawings. FIG. 21 is a diagram showing the light source unit 110, the color separation / synthesis unit 140, and the projection unit 150 according to the second embodiment. The second embodiment exemplifies a projection display apparatus 100 that supports a DLP (Digital Light Processing) method (registered trademark).

As shown in FIG. 21, the light source unit 110 includes a plurality of solid light sources 111W, a plurality of optical fibers 113W, and a bundle portion 114W. As described above, the solid-state light source 111W is a semiconductor laser element such as an LD that emits white light W having coherence. An optical fiber 113W is connected to the solid light source 111W.

The optical fibers 113W connected to each solid light source 111W are bundled by a bundle portion 114W. That is, the light emitted from each solid light source 111W is transmitted by each optical fiber 113W and collected in the bundle portion 114W. The solid light source 111W is placed on a cooling jacket (not shown) for cooling the solid light source 111W.

The color separation / synthesis unit 140 includes a rod integrator 10W, a lens 21W, a lens 23, a mirror 34, and a mirror 35. The color separation / combination unit 140 includes a diffusion optical element 600.

The rod integrator 10W has a light incident surface, a light emitting surface, and a light reflecting side surface provided from the outer periphery of the light incident surface to the outer periphery of the light emitting surface. The rod integrator 10W makes the white light W emitted from the optical fiber 113W bundled by the bundle unit 114W uniform. That is, the rod integrator 10W makes the white light W uniform by reflecting the white light W on the light reflection side surface.

The rod integrator 10W may be a hollow rod having a light reflection side surface constituted by a mirror surface. The rod integrator 10W may be a solid rod made of glass or the like.

The lens 21W is a lens that converts the white light W into a substantially parallel light so that the DMD 500 is irradiated with the white light W. The lens 23 is a lens for substantially imaging the white light W on each DMD 500 while suppressing the expansion of the white light W. The mirror 34 and the mirror 35 reflect the white light W.

The color separation / synthesis unit 140 includes a lens 40, a prism 50, a prism 60, a prism 70, a prism 80, a prism 90, and a plurality of DMDs; Digital Micromirror Device (DMD500R, DMD500G, and DMD500B).

The lens 40 is a lens that makes the white light W substantially parallel so that each color component light is irradiated to each DMD 500.

The prism 50 is made of a translucent member and has a surface 51 and a surface 52. An air gap is provided between the prism 50 (surface 51) and the prism 60 (surface 61), and the angle at which the white light W is incident on the surface 51 (incident angle) is larger than the total reflection angle. The light W is reflected by the surface 51. On the other hand, an air gap is provided between the prism 50 (surface 52) and the prism 70 (surface 71), but the angle at which the white light W enters the surface 52 (incident angle) is smaller than the total reflection angle. The white light W reflected by the surface 51 passes through the surface 52.

The prism 60 is made of a translucent member and has a surface 61.

The prism 70 is made of a translucent member and has a surface 71 and a surface 72. An air gap is provided between the prism 50 (surface 52) and the prism 70 (surface 71), and the blue component light B reflected by the surface 72 and the blue component light B emitted from the DMD 500B are formed on the surface 71. Since the incident angle (incident angle) is larger than the total reflection angle, the blue component light B reflected by the surface 72 and the blue component light B emitted from the DMD 500B are reflected by the surface 71.

The surface 72 is a dichroic mirror surface that transmits the red component light R and the green component light G and reflects the blue component light B. Accordingly, among the light reflected by the surface 51, the red component light R and the green component light G are transmitted through the surface 72, and the blue component light B is reflected by the surface 72. The blue component light B reflected by the surface 71 is reflected by the surface 72.

The prism 80 is made of a translucent member and has a surface 81 and a surface 82. An air gap is provided between the prism 70 (surface 72) and the prism 80 (surface 81). The red component light R transmitted through the surface 81 and reflected by the surface 82 and the red component emitted from the DMD 500R. Since the angle (incident angle) at which the light R again enters the surface 81 is larger than the total reflection angle, the red component light R transmitted through the surface 81 and reflected by the surface 82 and the red component light R emitted from the DMD 500R are Reflected by the surface 81. On the other hand, since the angle (incident angle) at which the red component light R emitted from the DMD 500R and reflected by the surface 81 and then reflected by the surface 82 is incident on the surface 81 again is smaller than the total reflection angle, it is emitted from the DMD 500R. Then, the red component light R reflected by the surface 82 after being reflected by the surface 81 passes through the surface 81.

The surface 82 is a dichroic mirror surface that transmits the green component light G and reflects the red component light R. Accordingly, among the light transmitted through the surface 81, the green component light G is transmitted through the surface 82, and the red component light R is reflected by the surface 82. The red component light R reflected by the surface 81 is reflected by the surface 82. The green component light G emitted from the DMD 500G passes through the surface 82.

Here, the prism 70 separates the combined light including the red component light R and the green component light G and the blue component light B by the surface 72. The prism 80 separates the red component light R and the green component light G by the surface 82. That is, the prism 70 and the prism 80 function as a color separation element that separates each color component light.

In the second embodiment, the cutoff wavelength of the surface 72 of the prism 70 is provided between a wavelength band corresponding to green and a wavelength band corresponding to blue. The cut-off wavelength of the surface 82 of the prism 80 is provided between a wavelength band corresponding to red and a wavelength band corresponding to green.

On the other hand, the prism 70 combines the combined light including the red component light R and the green component light G and the blue component light B with the surface 72. The prism 80 combines the red component light R and the green component light G with the surface 82. That is, the prism 70 and the prism 80 function as a color composition element that synthesizes each color component light.

The prism 90 is made of a translucent member and has a surface 91. The surface 91 is configured to transmit the green component light G. The green component light G incident on the DMD 500G and the green component light G emitted from the DMD 500G pass through the surface 91.

DMD500R, DMD500G, and DMD500B are configured by a plurality of micromirrors, and the plurality of micromirrors are movable. Each minute mirror basically corresponds to one pixel. The DMD 500R switches whether to reflect the red component light R toward the projection unit 150 by changing the angle of each micromirror. Similarly, the DMD 500G and the DMD 500B switch whether to reflect the green component light G and the blue component light B toward the projection unit 150 by changing the angle of each micromirror.

The projection unit 150 includes a projection lens group 151 and a concave mirror 152.

The projection lens group 151 emits light (image light) emitted from the color separation / synthesis unit 140 to the concave mirror 152 side.

The concave mirror 152 reflects light (image light) emitted from the projection lens group 151. The concave mirror 152 condenses the image light and then widens the image light. For example, the concave mirror 152 is an aspherical mirror having a concave surface on the projection lens group 151 side.

The image light collected by the concave mirror 152 passes through a transmission region provided on the inclined surface 181 of the top plate recess 180 provided on the top plate 240. The transmission region provided on the inclined surface 181 is preferably provided in the vicinity of the position where the image light is collected by the concave mirror 152.

The concave mirror 152 is accommodated in the space formed by the front-side convex portion 170 as described above. For example, the concave mirror 152 is preferably fixed inside the front side convex portion 170. In addition, the shape of the inner surface of the front side convex portion 170 is preferably a shape along the concave mirror 152.

Here, in the second embodiment, the color separation / synthesis unit 140 includes the diffusion optical element 600 (speckle noise reduction element) as described above. The diffusing optical element 600 is provided between the light source unit 110 and the DMD 500 on the optical path of the light emitted from the light source unit 110, and is a unit that reduces speckle noise of the light emitted from the light source unit 110. is there. In other words, the diffusion optical element 600 is an optical element that reduces the spatial coherence of the white light W in order to reduce speckle. Specifically, the diffusion optical element 600 diffuses the white light W made uniform by the rod integrator 10W and transmits the white light W. For example, the configuration shown below can be considered as the configuration of the diffusing optical element 600.

(First configuration example)
In the first configuration example, as illustrated in FIG. 22, the diffusion optical element 600 includes a glass plate 710, a diffusion surface 711, and a diffusion surface 712.

The glass plate 710 is disposed between the light source unit 110 and the DMD 500 on the optical path of the light emitted from the light source unit 110. Specifically, in the second embodiment, the glass plate 710 is disposed on the light emitting side of the rod integrator 10W.

The glass plate 710 has two main surfaces, and the two main surfaces are surfaces substantially perpendicular to the optical axis of the light emitted from the light source unit 110.

The diffusion surface 711 is provided on one main surface of the two main surfaces of the glass plate 710. Specifically, the diffusing surface 711 is provided on the main surface provided on the light source unit 110 side. Further, the diffusion surface 711 is provided in a central region including the optical axis center of the light emitted from the light source unit 110. The diffusion surface 711 diffuses the light emitted from the light source unit 110 and transmits the light emitted from the light source unit 110.

The diffusion surface 712 is provided on the other main surface of the two main surfaces of the glass plate 710. Specifically, the diffusion surface 712 is provided on the main surface provided on the opposite side of the light source unit 110. Further, the diffusing surface 712 is provided in a peripheral region provided around the central region including the optical axis center of the light emitted from the light source unit 110. The diffusion surface 712 diffuses the light emitted from the light source unit 110 and transmits the light emitted from the light source unit 110.

As described above, in the central region, the light emitted from the light source unit 110 is diffused by both the diffusion surface 711 and the diffusion surface 712. In the peripheral region, the light emitted from the light source unit 110 is diffused only by the diffusion surface 712.

Therefore, in the entire diffusion optical element 600, the diffusivity in the central region is larger than that in the peripheral region.

(Second configuration example)
In the second configuration example, as illustrated in FIG. 23, the diffusion optical element 600 includes a glass plate 720, a diffusion surface 721, a glass plate 730, and a diffusion surface 731.

The glass plate 720 has two main surfaces, and the two main surfaces are surfaces substantially perpendicular to the optical axis of the light emitted from the light source unit 110. Similarly, the glass plate 730 has two main surfaces, and the two main surfaces are surfaces substantially perpendicular to the optical axis of the light emitted from the light source unit 110.

The diffusion surface 721 is provided on one main surface of the two main surfaces of the glass plate 720. For example, the diffusing surface 721 is provided on the main surface provided on the light source unit 110 side. Further, the diffusing surface 721 is provided in a central region including the optical axis center of the light emitted from the light source unit 110. The diffusion surface 721 diffuses the light emitted from the light source unit 110 and transmits the light emitted from the light source unit 110. The diffusing surface 721 may be provided on the main surface provided on the opposite side of the light source unit 110.

The diffusion surface 731 is provided on one main surface of the two main surfaces of the glass plate 730. For example, the diffusing surface 731 is provided on the main surface provided on the light source unit 110 side. Further, the diffusing surface 731 is provided in a peripheral region provided around the central region including the optical axis center of the light emitted from the light source unit 110. The diffusion surface 731 diffuses light emitted from the light source unit 110 and transmits light emitted from the light source unit 110. The diffusing surface 731 may be provided on a main surface provided on the opposite side of the light source unit 110.

Thus, in the central region, the light emitted from the light source unit 110 is diffused by both the diffusion surface 721 and the diffusion surface 731. In the peripheral region, the light emitted from the light source unit 110 is diffused only by the diffusion surface 731.

Therefore, in the entire diffusion optical element 600, the diffusivity in the central region is larger than that in the peripheral region.

(Configuration of control unit)
Hereinafter, a control unit according to the second embodiment will be described with reference to the drawings. FIG. 24 is a block diagram showing a control unit 800 according to the second embodiment. The control unit 800 is provided in the projection display apparatus 100 and controls the projection display apparatus 100.

The control unit 800 converts the video input signal into a video output signal. The video input signal includes a red input signal R _in , a green input signal G _in, and a blue input signal B _in . The video output signal includes a red output signal _Rout , a green output signal _Gout, and a blue output signal _Bout . The video input signal and the video output signal are signals input for each of a plurality of pixels constituting one frame.

As shown in FIG. 24, the control unit 800 includes an element control unit 810. The element control unit 810 controls the diffusion optical element 600 so as to operate in a predetermined operation pattern. For example, the element control unit 810 causes the diffusion optical element 600 to vibrate in a predetermined operation pattern under the control of a driving device that drives the diffusion optical element 600.

When the diffusing optical element 600 is the second configuration example shown in FIG. 23, the element control unit 810 can independently control the glass plate 720 (diffusing surface 721) and the glass plate 730 (diffusing surface 731). it can. In such a case, when the vibration phase of the diffusing surface 721 is φ and the vibration phase of the diffusing surface 731 is φ ′, the control unit 800 allows the diffusion optical element to satisfy the relationship of φ ′ ≠ φ + nπ. 600 may be controlled.

(Action and effect)
In the second embodiment, the diffusing optical element 600 makes the spatial distribution of the light intensity uniform on the exit pupil plane of the projection unit. Accordingly, since the intensity of light from the aperture plane (exit pupil plane) of the projection unit to one point on the projection plane has a uniform angular distribution, the speckle noise reduction effect due to angle superposition is sufficiently exerted, and speckle noise is reduced. It can be effectively removed.

In the second embodiment, the diffusing optical element 600 has a configuration in which the diffusivity of the central region is larger than the diffusivity of the peripheral region. That is, the light passing through the central region of the diffusing optical element 600 is diffused more than the light passing through the peripheral region of the diffusing optical element 600. Accordingly, the spatial distribution of light intensity on the exit pupil plane of the projection unit is made uniform.

(Explanation of effect)
Hereinafter, effects of the diffusing optical element 600 according to the second embodiment will be described with reference to the drawings.

First, the spatial distribution of light intensity will be described for a case where the diffusing optical element 600 is not provided (prior art). 25 and 26 are diagrams for explaining the spatial distribution of light intensity according to the related art.

In addition, in FIG. 25, the optical structure provided in a projection type video display apparatus is shown typically. Specifically, in FIG. 25, the optical path of light emitted from the light source (rod integrator) is schematically illustrated in a straight line. FIG. 25 illustrates a rod integrator, a relay optical system, a light modulation element, and a projection unit as an optical configuration provided in the projection display apparatus.

The angular distribution of the light emitted from the light source is a Gaussian distribution centered at 0 °. Further, the aperture of the relay optical system and the aperture (exit pupil) of the projection unit have a conjugate relationship.

As shown in FIG. 25, in the case where the diffusing optical element 600 is not provided, the spatial distribution of the light intensity on the diaphragm surface of the relay optical system and the diaphragm surface (exit pupil plane) of the projection unit is the light emitted from the light source. It becomes a Gaussian distribution reflecting the angle distribution.

Therefore, when considering the light flux from the aperture plane (exit pupil plane) of the projection unit to one point on the projection plane (center point of the projection plane), as shown in FIG. 26, the light flux from the peripheral region to one point on the projection plane. Is smaller than the light flux from the central region to one point on the projection surface. That is, the intensity of light reaching one point on the projection surface does not have a uniform angular distribution.

As described above, in the conventional technology, since the intensity of light reaching one point on the projection surface does not have a uniform angle distribution, the speckle noise reduction effect due to the angle superposition is not sufficiently exhibited, and speckle noise is observed. End up.

Second, the spatial distribution of light intensity will be described for the case where the diffusing optical element 600 is provided (second embodiment). 27 and 28 are diagrams for explaining the spatial distribution of light intensity according to the second embodiment.

In FIG. 27, an optical configuration provided in the projection display apparatus is schematically shown. Specifically, in FIG. 27, the optical path of light emitted from the light source (rod integrator) is schematically illustrated in a straight line. In FIG. 27, as an optical configuration provided in the projection display apparatus, a rod integrator (for example, rod integrator 10W), a relay optical system (lens 21W, lens 23, lens 40), and a light modulation element (for example, DMD 500). In addition, a projection unit (for example, a projection lens group 151) is illustrated.

As in the prior art, the angular distribution of light emitted from the light source is a Gaussian distribution centered on 0 °. Further, the aperture of the relay optical system and the aperture (exit pupil) of the projection unit have a conjugate relationship.

As shown in FIG. 27, in the case where the diffusion optical element 600 is provided, the spatial distribution of the light intensity on the diaphragm surface of the relay optical system and the diaphragm surface (exit pupil plane) of the projection unit is made uniform by the diffusion optical element 600. Is done.

Therefore, when considering the light flux from the aperture plane (exit pupil plane) of the projection unit to one point on the projection plane, the intensity of light reaching one point on the projection plane has a uniform angular distribution as shown in FIG.

As described above, in the second embodiment, the light passing through the central region of the diffusing optical element 600 is diffused more than the light passing through the peripheral region of the diffusing optical element 600. Therefore, the light on the aperture plane (exit pupil plane) of the projection unit The spatial distribution of intensity is made uniform. As a result, the intensity of light reaching one point on the projection surface has a uniform angular distribution, the effect of reducing speckle noise by the angle superposition is sufficiently exhibited, and speckle noise is efficiently removed.

[Outline of Third Embodiment]
(Problem of the third embodiment)
If a light diffusing element is installed in the diverging light path of the projection display apparatus and the light diffusing element vibrates in a direction parallel to the traveling direction of light, the light divergence angle increases, so that it cannot be captured by the projection lens. The light of the angle component is lost.

Further, in order to prevent this light loss from occurring, a projection lens having a small F-number is required, but the degree of difficulty increases in designing to obtain sufficient imaging performance. The cost increases because it is required.

(Configuration of Third Embodiment)
The projection display apparatus according to the third embodiment reduces speckle noise by oscillating, swinging, or rotating a light source unit configured by a coherent light source and substantially orthogonal to the optical axis of the light source unit. A projection-type image display device comprising: a speckle noise reducing element to be controlled; a light modulation element that modulates light emitted from the coherent light source; and a projection unit that projects light modulated by the light modulation element. The speckle noise reduction element has a first lens array having a focal length f and a second lens array having a focal length f ′, and the interval between the media sandwiched between the lens arrays makes the absolute refractive index n. Is approximately (f + f ′) / n.

The speckle noise reduction element has a first lens array having a focal length f and a second lens array having a focal length f ′, and the distance between the media sandwiched between the lens arrays is an absolute refractive index n. Is approximately (f + f ′) / n. With this configuration, the incident-side divergence angle of the light incident on the speckle noise reduction element can be made the same as the emission-side divergence angle of the emitted light. Accordingly, since the divergence angle of light before and after entering the speckle noise reduction element does not increase, an angle component that cannot be captured by the projection lens is hardly generated, and light loss of the projection display apparatus is reduced. Can do.

Also, the position and phase of each light beam emitted from the speckle noise reduction element changes with time by vibrating, swinging, or rotating the speckle noise reduction element arranged in the illumination optical system. Thereby, since the angle and phase of each light ray incident on each point on the screen surface change with time, the speckle pattern is superimposed on time, and the speckle noise that is visually recognized is reduced.

Therefore, in a projection display apparatus using a coherent light source, speckle noise can be reduced, and light loss due to an increase in light divergence angle can be reduced.

[Third Embodiment]
(Configuration of projection display device)
The configuration of the projection display apparatus according to the third embodiment will be described below with reference to the drawings. FIG. 29 is a perspective view showing a projection display apparatus 100 according to the third embodiment. FIG. 30 is a side view of the projection display apparatus 100 according to the third embodiment.

As shown in FIGS. 29 and 30, the projection display apparatus 100 has a casing 200 and projects an image on the projection plane 300. The projection display apparatus 100 is arranged along a first arrangement surface (wall surface 420 shown in FIG. 30) and a second arrangement surface (floor surface 410 shown in FIG. 30) substantially perpendicular to the first arrangement surface.

Here, the third embodiment exemplifies a case in which the projection display apparatus 100 projects image light onto the projection plane 300 provided on the wall surface (wall surface projection). The arrangement of the casing 200 in such a case is referred to as a wall surface projection arrangement. In the third embodiment, the first arrangement surface that is substantially parallel to the projection plane 300 is the wall surface 420.

In the third embodiment, a horizontal direction parallel to the projection plane 300 is referred to as a “width direction”. The normal direction of the projection plane 300 is referred to as “depth direction”. A direction orthogonal to both the width direction and the depth direction is referred to as a “height direction”.

The housing 200 has a substantially rectangular parallelepiped shape. The size of the housing 200 in the depth direction and the size of the housing 200 in the height direction are smaller than the size of the housing 200 in the width direction. The size of the casing 200 in the depth direction is substantially equal to the projection distance from the reflection mirror (concave mirror 152 shown in FIG. 30) to the projection plane 300. In the width direction, the size of the casing 200 is substantially equal to the size of the projection plane 300. In the height direction, the size of the housing 200 is determined according to the position where the projection plane 300 is provided.

Specifically, the housing 200 includes a projection surface side wall 210, a front surface side wall 220, a bottom plate 230, a top plate 240, a first side surface side wall 250, and a second side surface side wall 260. .

The projection surface side wall 210 is a plate-like member facing a first arrangement surface (in the third embodiment, a wall surface 420) substantially parallel to the projection surface 300. The front side wall 220 is a plate-like member provided on the opposite side of the projection plane side wall 210. The bottom plate 230 is a plate-like member that faces a second arrangement surface (in the third embodiment, the floor surface 410) that is substantially perpendicular to the first arrangement surface that is substantially parallel to the projection plane 300. The top plate 240 is a plate-like member provided on the opposite side of the bottom plate 230. The first side wall 250 and the second side wall 260 are plate-like members that form both ends of the housing 200 in the width direction.

The housing 200 accommodates the light source unit 110, the power supply unit 120, the cooling unit 130, the color separation / combination unit 140, and the projection unit 150. The projection surface side sidewall 210 has a projection surface side recess 160A and a projection surface side recess 160B. The front side wall 220 has a front side convex portion 170. The top plate 240 has a top plate recess 180. The first side wall 250 has a cable terminal 190.

The light source unit 110 is a unit composed of a plurality of coherent light sources (coherent light source 111 shown in FIG. 32). Each coherent light source is a light source such as an LD (Laser Diode). In the third embodiment, the light source unit 110 includes a red coherent light source that emits red component light R (red coherent light source 111R shown in FIG. 32) and a green coherent light source that emits green component light G (green coherent light source shown in FIG. 32). Light source 111G) and a blue coherent light source that emits blue component light B (blue coherent light source 111B shown in FIG. 32). Details of the light source unit 110 will be described later (see FIG. 32).

The power supply unit 120 is a unit that supplies power to the projection display apparatus 100. For example, the power supply unit 120 supplies power to the light source unit 110 and the cooling unit 130.

The cooling unit 130 is a unit that cools a plurality of coherent light sources provided in the light source unit 110. Specifically, the cooling unit 130 cools each coherent light source by cooling a cooling jacket (cooling jacket 131 shown in FIG. 32) on which each coherent light source is placed.

The cooling unit 130 is configured to cool the power supply unit 120 and the light modulation element (DMD 500 described later) in addition to each coherent light source.

The color separation / combination unit 140 combines the red component light R emitted from the red coherent light source, the green component light G emitted from the green coherent light source, and the blue component light B emitted from the blue coherent light source. The color separation / combination unit 140 separates the combined light including the red component light R, the green component light G, and the blue component light B, and modulates the red component light R, the green component light G, and the blue component light B. Further, the color separation / combination unit 140 recombines the red component light R, the green component light G, and the blue component light B, and emits image light to the projection unit 150. Details of the color separation / synthesis unit 140 will be described later (see FIG. 33).

The projection unit 150 projects the light (image light) emitted from the color separation / synthesis unit 140 onto the projection plane 300. Specifically, the projection unit 150 projects the light emitted from the color separation / synthesis unit 140 onto the projection plane 300 (projection lens group 151 shown in FIG. 33) and the projection lens group. A reflecting mirror (concave mirror 152 shown in FIG. 33) that reflects light toward the projection plane 300; Details of the projection unit 150 will be described later.

The projection surface side recess 160A and the projection surface side recess 160B are provided on the projection surface side wall 210 and have a shape that is recessed inside the housing 200. The projection surface side recess 160 </ b> A and the projection surface side recess 160 </ b> B extend to the end of the housing 200. The projection surface side recess 160 </ b> A and the projection surface side recess 160 </ b> B are provided with vent holes that communicate with the inside of the housing 200.

In the third embodiment, the projection surface side recess 160A and the projection surface side recess 160B extend along the width direction of the housing 200. For example, the projection surface side recess 160 </ b> A is provided with an air inlet for allowing air outside the housing 200 to enter the housing 200 as a vent. The projection surface side recess 160 </ b> B is provided with an exhaust port for venting air inside the housing 200 to the outside of the housing 200 as a vent.

The front side convex portion 170 is provided on the front side wall 220 and has a shape protruding to the outside of the housing 200. The front side convex portion 170 is provided at the approximate center of the front side wall 220 in the width direction of the housing 200. A reflection mirror (concave mirror 152 shown in FIG. 33) provided in the projection unit 150 is accommodated in a space formed by the front-side convex portion 170 inside the housing 200.

The top plate recess 180 is provided in the top plate 240 and has a shape that is recessed inside the housing 200. The top plate recess 180 has an inclined surface 181 that goes down toward the projection plane 300 side. The inclined surface 181 has a transmission region that transmits (projects) the light emitted from the projection unit 150 to the projection surface 300 side.

The cable terminal 190 is provided on the first side wall 250 and is a terminal such as a power terminal or a video terminal. The cable terminal 190 may be provided on the second side wall 260.

(Arrangement of units in the width direction of the housing)
Hereinafter, the arrangement of the units in the width direction according to the third embodiment will be described with reference to the drawings. FIG. 31 is a top view of the projection display apparatus 100 according to the third embodiment.

As shown in FIG. 31, the projection unit 150 is arranged in the approximate center of the casing 200 in the horizontal direction parallel to the projection plane 300 (the width direction of the casing 200).

The light source unit 110 and the cooling unit 130 are arranged side by side with the projection unit 150 in the width direction of the housing 200. Specifically, the light source unit 110 is arranged side by side on the one side (second side wall 260 side) of the projection unit 150 in the width direction of the casing 200. The cooling unit 130 is arranged side by side on the other side (first side wall 250 side) of the projection unit 150 in the width direction of the casing 200.

The power supply unit 120 is arranged side by side with the projection unit 150 in the width direction of the casing 200. Specifically, the power supply unit 120 is arranged side by side on the light source unit 110 side with respect to the projection unit 150 in the width direction of the casing 200. The power supply unit 120 is preferably disposed between the projection unit 150 and the light source unit 110.

(Configuration of light source unit)
Hereinafter, the configuration of the light source unit according to the third embodiment will be described with reference to the drawings. FIG. 32 is a diagram illustrating the light source unit 110 according to the third embodiment.

32, the light source unit 110 includes a plurality of red coherent light sources 111R, a plurality of green coherent light sources 111G, and a plurality of blue coherent light sources 111B.

The red coherent light source 111R is a red coherent light source such as an LD that emits the red component light R as described above. The red coherent light source 111R has a head 112R, and an optical fiber 113R is connected to the head 112R.

The optical fibers 113R connected to the heads 112R of each red coherent light source 111R are bundled by a bundle portion 114R. That is, the light emitted from each red coherent light source 111R is transmitted by each optical fiber 113R and collected in the bundle portion 114R.

The red coherent light source 111R is placed on the cooling jacket 131R. For example, the red coherent light source 111R is fixed to the cooling jacket 131R by screwing or the like. Therefore, the red coherent light source 111R is cooled by the cooling jacket 131R.

The green coherent light source 111G is a green coherent light source such as an LD that emits the green component light G as described above. The green coherent light source 111G has a head 112G, and an optical fiber 113G is connected to the head 112G.

The optical fiber 113G connected to the head 112G of each green coherent light source 111G is bundled by the bundle unit 114G. That is, the light emitted from each green coherent light source 111G is transmitted by each optical fiber 113G and collected in the bundle unit 114G.

The green coherent light source 111G is placed on the cooling jacket 131G. For example, the green coherent light source 111G is fixed to the cooling jacket 131G by screwing or the like. Therefore, the green coherent light source 111G is cooled by the cooling jacket 131G.

The coherent light source 111B is a blue coherent light source such as an LD that emits the blue component light B as described above. The blue coherent light source 111B has a head 112B, and an optical fiber 113B is connected to the head 112B.

The optical fibers 113B connected to the head 112B of each blue coherent light source 111B are bundled by a bundle unit 114B. That is, the light emitted from each blue coherent light source 111B is transmitted by each optical fiber 113B and collected in the bundle portion 114B.

The blue coherent light source 111B is placed on the cooling jacket 131B. For example, the blue coherent light source 111B is fixed to the cooling jacket 131B by screwing or the like. Therefore, the blue coherent light source 111B is cooled by the cooling jacket 131B.

(Configuration of color separation / synthesis unit and projection unit)
Hereinafter, configurations of the color separation / synthesis unit and the projection unit according to the third embodiment will be described with reference to the drawings. FIG. 33 is a diagram showing a color separation / synthesis unit 140 and a projection unit 150 according to the third embodiment. The third embodiment exemplifies a projection display apparatus 100 that supports a DLP (Digital Light Processing) method (registered trademark).

As shown in FIG. 33, the color separation / synthesis unit 140 includes a first unit 141 and a second unit 142.

The first unit 141 combines the red component light R, the green component light G, and the blue component light B, and outputs the combined light including the red component light R, the green component light G, and the blue component light B to the second unit 142. To do.

Specifically, the first unit 141 includes a plurality of rod integrators (rod integrator 10R, rod integrator 10G and rod integrator 10B), a lens group (lens 21R, lens 21G, lens 21B, lens 22, lens 23), And a mirror group (mirror 31, mirror 32, mirror 33, mirror 34, and mirror 35).

The rod integrator 10R has a light incident surface, a light emitting surface, and a light reflecting side surface provided from the outer periphery of the light incident surface to the outer periphery of the light emitting surface. The rod integrator 10R makes the red component light R emitted from the optical fiber 113R bundled by the bundle portion 114R uniform. In other words, the rod integrator 10R makes the red component light R uniform by reflecting the red component light R on the light reflection side surface.

The rod integrator 10G has a light incident surface, a light emitting surface, and a light reflecting side surface provided from the outer periphery of the light incident surface to the outer periphery of the light emitting surface. The rod integrator 10G makes the green component light G emitted from the optical fiber 113G bundled by the bundle portion 114G uniform. That is, the rod integrator 10G makes the green component light G uniform by reflecting the green component light G on the light reflection side surface.

The rod integrator 10B has a light incident surface, a light emitting surface, and a light reflecting side surface provided from the outer periphery of the light incident surface to the outer periphery of the light emitting surface. The rod integrator 10B makes the blue component light B emitted from the optical fiber 113B bundled by the bundle portion 114B uniform. That is, the rod integrator 10B makes the blue component light B uniform by reflecting the blue component light B on the light reflection side surface.

Note that the rod integrator 10R, the rod integrator 10G, and the rod integrator 10B may be hollow rods whose light-reflecting side surfaces are mirror surfaces. Further, the rod integrator 10R, the rod integrator 10G, and the rod integrator 10B may be solid rods made of glass or the like.

The speckle noise reduction element 20R is disposed immediately after the light exit surface of the rod integrator 10R that is substantially conjugate to the light modulation element and the screen surface, and is perpendicular to the optical axis of the red component light R from the rod integrator 10R. Periodically oscillates, swings, or rotates in the direction of. Here, vibration means reciprocating with respect to a specific axis around the optical axis of light, or reciprocating in parallel with the optical axis of light, and oscillation means that the optical axis of light is reciprocated. In contrast, it indicates that the surface moves in a substantially circular plane, and the rotation indicates that the rotation is performed around a specific axis parallel to the optical axis of light. The speckle noise reduction element 20R periodically vibrates, swings, or rotates, so that the red component light R emitted from the rod integrator 20R passes through the speckle noise reduction element 20R and is emitted. The position and phase can be changed according to time.

The speckle noise reduction element 20G is disposed immediately after the light exit surface of the rod integrator 10G that is a substantially conjugate surface of the light modulation element and the screen surface, and is perpendicular to the optical axis of the green component light G from the rod integrator 10G. Periodically oscillates, swings, or rotates in the direction of. The speckle noise reduction element 20G periodically vibrates, swings, or rotates so that the red component light G emitted from the rod integrator 20G passes through the speckle noise reduction element 20G and is emitted. The position and phase can be changed according to time.

The speckle noise reduction element 20B is disposed immediately after the light exit surface of the rod integrator 10B, which is a substantially conjugate surface of the light modulation element and the screen surface, and is perpendicular to the optical axis of the blue component light B from the rod integrator 10B. Are periodically vibrated, oscillated, or rotated in the direction of. The speckle noise reducing element 20B periodically vibrates, swings, or rotates so that the green component light B emitted from the rod integrator 20B is emitted from the speckle noise reducing element 20B. When the light passes through the reduction element 20B and is emitted, the emission position and phase of each light beam can be changed according to time.

Speckle noise is observed as an irregular granular intensity distribution when coherent light such as laser light is scattered at each point on a rough surface such as a screen and interferes with an irregular phase relationship caused by the surface roughness. It is a phenomenon. By oscillating, swinging, or rotating the speckle noise reduction element arranged in the illumination optical system, the position and phase of each light beam emitted from the speckle noise reduction element changes with time. Thereby, since the angle and phase of each light ray incident on each point on the screen surface change with time, the speckle pattern is superimposed on time, and the speckle noise that is visually recognized is reduced.

The lens 21R is a relay lens that relays the red component light R so that the red component light R is irradiated onto the DMD 500R. The lens 21G is a relay lens that relays the green component light G so that the DMD 500G is irradiated with the green component light G. The lens 21B is a relay lens that relays the blue component light B so that the blue component light B is irradiated onto the DMD 500B.

The lens 22 is a relay lens for substantially imaging the red component light R and the green component light G on the DMD 500R and DMD 500G while suppressing the expansion of the red component light R and the green component light G. The lens 23 is a relay lens for substantially imaging the blue component light B on the DMD 500B while suppressing the expansion of the blue component light B.

The mirror 31 reflects the red component light R emitted from the rod integrator 10R. The mirror 32 is a dichroic mirror that reflects the green component light G emitted from the rod integrator 10G and transmits the red component light R. The mirror 33 is a dichroic mirror that transmits the blue component light B emitted from the rod integrator 10B and reflects the red component light R and the green component light G.

Mirror 34 reflects red component light R, green component light G, and blue component light B. The mirror 35 reflects the red component light R, the green component light G, and the blue component light B to the second unit 142 side. In FIG. 33, each component is shown in a plan view for the sake of simplicity. However, the mirror 35 obliquely reflects the red component light R, the green component light G, and the blue component light B in the height direction. Reflect on.

The second unit 142 separates the combined light including the red component light R, the green component light G, and the blue component light B, and modulates the red component light R, the green component light G, and the blue component light B. Subsequently, the second unit 142 recombines the red component light R, the green component light G, and the blue component light B, and emits image light to the projection unit 150 side.

Specifically, the second unit 142 includes a lens 40, a prism 50, a prism 60, a prism 70, a prism 80, a prism 90, and a plurality of DMDs; Digital Micromirror Device (DMD500R, DMD500G, and DMD500B). Have

The lens 40 is a relay lens that relays the light emitted from the first unit 141 so that each color component light is irradiated to each DMD.

The prism 50 is made of a translucent member and has a surface 51 and a surface 52. An air gap is provided between the prism 50 (surface 51) and the prism 60 (surface 61), and the angle (incident angle) at which the light emitted from the first unit 141 enters the surface 51 is the total reflection angle. Therefore, the light emitted from the first unit 141 is reflected by the surface 51. On the other hand, an air gap is provided between the prism 50 (surface 52) and the prism 70 (surface 71), but the angle at which the light emitted from the first unit 141 enters the surface 52 (incident angle) is all. Since it is smaller than the reflection angle, the light reflected by the surface 51 passes through the surface 52.

The prism 60 is made of a translucent member and has a surface 61.

The prism 70 is made of a translucent member and has a surface 71 and a surface 72. An air gap is provided between the prism 50 (surface 52) and the prism 70 (surface 71), and the blue component light B reflected by the surface 72 and the blue component light B emitted from the DMD 500B are formed on the surface 71. Since the incident angle (incident angle) is larger than the total reflection angle, the blue component light B reflected by the surface 72 and the blue component light B emitted from the DMD 500B are reflected by the surface 71.

The surface 72 is a dichroic mirror surface that transmits the red component light R and the green component light G and reflects the blue component light B. Accordingly, among the light reflected by the surface 51, the red component light R and the green component light G are transmitted through the surface 72, and the blue component light B is reflected by the surface 72. The blue component light B reflected by the surface 71 is reflected by the surface 72.

The prism 80 is made of a translucent member and has a surface 81 and a surface 82. An air gap is provided between the prism 70 (surface 72) and the prism 80 (surface 81). The red component light R transmitted through the surface 81 and reflected by the surface 82 and the red component emitted from the DMD 500R. Since the angle (incident angle) at which the light R again enters the surface 81 is larger than the total reflection angle, the red component light R transmitted through the surface 81 and reflected by the surface 82 and the red component light R emitted from the DMD 500R are Reflected by the surface 81. On the other hand, since the angle (incident angle) at which the red component light R emitted from the DMD 500R and reflected by the surface 81 and then reflected by the surface 82 is incident on the surface 81 again is smaller than the total reflection angle, it is emitted from the DMD 500R. Then, the red component light R reflected by the surface 82 after being reflected by the surface 81 passes through the surface 81.

The surface 82 is a dichroic mirror surface that transmits the green component light G and reflects the red component light R. Accordingly, among the light transmitted through the surface 81, the green component light G is transmitted through the surface 82, and the red component light R is reflected by the surface 82. The red component light R reflected by the surface 81 is reflected by the surface 82. The green component light G emitted from the DMD 500G passes through the surface 82.

Here, the prism 70 separates the combined light including the red component light R and the green component light G and the blue component light B by the surface 72. The prism 80 separates the red component light R and the green component light G by the surface 82. That is, the prism 70 and the prism 80 function as a color separation element that separates each color component light.

In the third embodiment, the cutoff wavelength of the surface 72 of the prism 70 is provided between the wavelength band corresponding to green and the wavelength band corresponding to blue. The cut-off wavelength of the surface 82 of the prism 80 is provided between a wavelength band corresponding to red and a wavelength band corresponding to green.

On the other hand, the prism 70 combines the combined light including the red component light R and the green component light G and the blue component light B with the surface 72. The prism 80 combines the red component light R and the green component light G with the surface 82. That is, the prism 70 and the prism 80 function as a color composition element that synthesizes each color component light.

The prism 90 is made of a translucent member and has a surface 91. The surface 91 is configured to transmit the green component light G. The green component light G incident on the DMD 500G and the green component light G emitted from the DMD 500G pass through the surface 91.

DMD500R, DMD500G, and DMD500B are configured by a plurality of micromirrors, and the plurality of micromirrors are movable. Each minute mirror basically corresponds to one pixel. The DMD 500R switches whether to reflect the red component light R toward the projection unit 150 by changing the angle of each micromirror. Similarly, the DMD 500G and the DMD 500B switch whether to reflect the green component light G and the blue component light B toward the projection unit 150 by changing the angle of each micromirror.

The projection unit 150 includes a projection lens group 151 and a concave mirror 152.

The projection lens group 151 emits light (image light) emitted from the color separation / synthesis unit 140 to the concave mirror 152 side.

The concave mirror 152 reflects light (image light) emitted from the projection lens group 151. The concave mirror 152 condenses the image light and then widens the image light. For example, the concave mirror 152 is an aspherical mirror having a concave surface on the projection lens group 151 side.

The image light collected by the concave mirror 152 passes through a transmission region provided on the inclined surface 181 of the top plate recess 180 provided on the top plate 240. The transmission region provided on the inclined surface 181 is preferably provided in the vicinity of the position where the image light is collected by the concave mirror 152.

The concave mirror 152 is accommodated in the space formed by the front-side convex portion 170 as described above. For example, the concave mirror 152 is preferably fixed inside the front side convex portion 170. In addition, the shape of the inner surface of the front side convex portion 170 is preferably a shape along the concave mirror 152.

(Basic configuration of speckle noise reduction element)
FIG. 34 shows the speckle noise reduction element 20R, the speckle noise reduction element 20G, and the speckle noise reduction element 20B in detail. The speckle noise reduction element 20R, the speckle noise reduction element 20G, and the speckle noise reduction element 20B include an incident side microlens array 310, an element substrate 320, an emission side microlens array 312, and vibration applying means (not shown).

The incident side microlens array 310 is an aggregate of hemispherical microlenses formed innumerably on the light incident surface side of the speckle noise reduction element 20R, the speckle noise reduction element 20G, and the speckle noise reduction element 20B. is there. Each lens of the incident side microlens array 310 is a microlens having a refractive index of n and a focal length of f.

The element substrate 320 has the incident side microlens array 310 and the emission side microlens array 312 fixed with an ultraviolet curing adhesive. The element substrate 320 is a transparent substrate having a refractive index n and a thickness W. Note that the thickness W of the element substrate 320 is “2f / n” ± “error”. In other words, the thickness W of the element substrate 320 may not be strictly the same as “2f / n”, and may be approximately “2f / n”.

The emission side microlens array 312 is an aggregate of hemispherical microlenses formed innumerably on the light emission surface side of the speckle noise reduction element 20R, the speckle noise reduction element 20G, and the speckle noise reduction element 20B. is there. Each lens of the exit side microlens array 312 is a microlens having a refractive index n and a focal length f.

The incident side microlens array 310, the element substrate 320, and the emission side microlens array 312 are fixed with an ultraviolet curable adhesive, but the present invention is not limited thereto. The side microlens array 312 may be formed by integral molding. By doing so, it is not necessary to attach the incident side microlens array 310, the element substrate 320, and the emission side microlens array 312 or to adjust the optical axis.

Next, the optical path of light traveling through the speckle noise reducing element 20R, the speckle noise reducing element 20G, and the speckle noise reducing element 20B will be described with reference to FIG. Light emitted from the emission end faces of the rod integrator 10R, rod integrator 10G, and rod integrator 10B is incident on the incident side microlens array 310 that is separated by a distance 2f. The light incident on the incident side microlens array 310 is refracted and passes through the inside of the incident side microlens array 310 and the element substrate 320. Refraction occurs only on the incident surface of the incident side microlens array 310, and no refraction occurs on the boundary surface between the incident side microlens array 310 and the element substrate 320 having the same refractive index.

Since the thickness of the element substrate 320 is approximately 2 f / n, the light that has passed through the element substrate 320 is imaged by the emission-side microlens array 312 fixed to the emission side of the element substrate 320.

Since the focal length of the exit side microlens array 312 is f and is the same as that of the entrance side microlens array 310, the entrance side divergence angle θ and the exit side divergence angle η are the same.

As described above, since the exit-side divergence angle η is the same as the incident-side divergence angle θ, it is difficult to generate light at an angle that cannot be taken into the projection lens 151, and light loss used for the projected image is unlikely to occur.

Next, the speckle noise reduction element 20R, the speckle noise reduction element 20G, and the speckle noise reduction element 20B are vibrated, oscillated, or rotated, so that the optical path length of incident light changes with time, and the speckle noise reduction element. A phenomenon in which the emission position and phase of the light emitted from the light changes with time will be described with reference to FIGS.

FIG. 35 (a) is a view focusing on a pair of microlenses of the incident side microlens array 310 and the emission side microlens array 312. FIG.

The light emitted from the emission end faces of the rod integrator 10R, the rod integrator 10G, and the rod integrator 10B is incident on the incident-side microlens 311 that is separated by a distance 2f. The light incident on the incident side microlens 311 is refracted and passes through the inside of the incident side microlens 311 and the element substrate 320. Refraction occurs only on the incident surface of the incident side microlens 311, and no refraction occurs on the boundary surface between the incident side microlens 311 and the element substrate 320 having the same refractive index.

Since the thickness of the element substrate 320 is approximately 2 f / n, the light passing through the element substrate 320 forms an image at the center of the emission side microlens 313 fixed to the emission side of the element substrate 320.

FIG. 35B shows an optical path of light when the speckle noise reduction element 20R, the speckle noise reduction element 20G, and the speckle noise reduction element 20B move upward due to vibration with respect to FIG. FIG.

FIG. 35C shows the optical path of light when the speckle noise reduction element 20R, the speckle noise reduction element 20G, and the speckle noise reduction element 20B move downward due to vibration with respect to FIG. FIG.

For example, when the speckle noise reduction element 20R, the speckle noise reduction element 20G, and the speckle noise reduction element 20B vibrate up and down, the positions where the emission light of the emission side microlens is emitted are shown in FIGS. c) is different. Further, when the speckle noise reducing element 20R, the speckle noise reducing element 20G, and the speckle noise reducing element 20B vibrate up and down, the light passing through the different optical path lengths shown in FIGS. 35 (a), (b), and (c). Will be imaged. Therefore, the light emitted from the emission side microlens is emitted from the speckle noise reduction element 20R, the speckle noise reduction element 20G, and the speckle noise reduction element 20B as light having different phases.

As a result, the angle and phase of each light ray incident on each point on the screen surface change with time, so that the speckle pattern is superimposed on time and the visible speckle noise is reduced.

(Application configuration of speckle noise reduction element)
Next, returning to FIG. 34, the microlenses of the speckle noise reducing element 20R, the speckle noise reducing element 20G, and the speckle noise reducing element 20B will be described in detail. The speckle noise reduction element 20R, the speckle noise reduction element 20G, and the speckle noise reduction element 20B emit all the incident light when the light emitted from the distance of 2f is within the incident side divergence angle θ. The light can be emitted within an angle η. That is, assuming that the diameters of the incident side microlens 311 and the emission side microlens 313 are d, the relationship between the incident side divergence angle θ and the emission side divergence angle η is θ = η when the following conditions are satisfied.

If the diameters of the incident-side microlens 311 and the emission-side microlens 313 are designed according to the above conditions, the emission-side divergence angle η is the same as the incident-side divergence angle θ compared to the basic configuration of the speckle noise reduction element. Therefore, it is difficult to generate light at an angle that cannot be captured by the projection lens, and it is difficult to cause light loss used in a projected image.

In the above embodiment, the element substrate 320 is disposed between the incident-side microlens array 310 and the emission-side microlens array 312, but the present invention is not limited to this configuration, and the incident-side microlens array 310 and the emission-side microlens array 310 are arranged. The side microlens array 312 may be arranged independently, and each distance may be separated by 2f.

[Modification 1]
Hereinafter, Modification 1 of the third embodiment will be described with reference to the drawings. In the following, differences from the third embodiment will be mainly described.

Specifically, in the third embodiment, the light source unit 110 includes a red coherent light source 111R, a green coherent light source 111G, and a blue coherent light source 111B, and the color separation / synthesis unit 140 includes the rod integrator 10R and the rod integrator 10G. And a rod integrator 10R, a rod integrator 10R that becomes a substantially conjugate plane of the screen surface, a speckle noise reduction element R20, a speckle noise reduction element G20, immediately before the light exit surface of the rod integrator 10G and the rod integrator 10B, and A speckle noise reduction element B20 was arranged.

On the other hand, in the first modification, the light source unit 110 has a white coherent light source, and the color separation / synthesis unit 140 has a single rod integrator 10 </ b> W on a substantially conjugate surface of the screen surface. A speckle noise reduction element W20 is disposed immediately before the light exit surface of the rod integrator 10W.

[Modification 2]
Hereinafter, Modification 1 of the third embodiment will be described with reference to the drawings. In the following, differences from the third embodiment will be mainly described.

Specifically, in the third embodiment, the incident side microlens array 310 and the emission side microlens array 312 are described as having the same focal length f. In Modification 2, a case will be described in which the focal length of the exit-side microlens array 312 is different from the focal length f of the incident-side microlens array 310 (the focal length is f ′).

The light incident on the incident side microlens array 310 is refracted and passes through the inside of the incident side microlens array 310 and the element substrate 320. The light that has passed through the inside of the element substrate 320 has a focal length f ′ of the emission-side microlens array 312, so that if the thickness of the element substrate 320 is approximately (f + f ′) / n, An image is formed by the fixed exit side microlens array 312.

Here, the relationship between the focal length f and the focal length f ′ satisfies f ≦ f ′. By doing so, the relationship between the incident-side divergence angle θ and the emission-side divergence angle η satisfies θ ≧ η. Therefore, light at an angle that cannot be captured by the projection lens 151 is unlikely to be generated, and light loss used for the projected image is unlikely to occur.

When the incident side microlens array 310 is composed of n × m microlenses, the exit side microlens array 312 needs to be composed of n × m microlenses.

(Configuration of color separation / synthesis unit and projection unit)
Hereinafter, configurations of the color separation / synthesis unit and the projection unit according to Modification 1 will be described with reference to the drawings. FIG. 35 is a diagram illustrating the color separation / synthesis unit 140 and the projection unit 150 according to the first modification. 35, the same code | symbol is attached | subjected about the structure similar to FIG.

As shown in FIG. 35, a speckle reduction element W20 is provided instead of the speckle noise reduction element R20, the speckle noise reduction element G20, and the speckle noise reduction element B20. The color separation / synthesis unit 140 includes a rod integrator 10W instead of the rod integrator 10R, the rod integrator 10G, and the rod integrator 10B. The color separation / combination unit 140 includes a lens 21W instead of the lens 21R, the lens 21G, and the lens 21B.

White light is incident on the rod integrator 10W from the bundle portion 114W. Here, it should be noted that white light is emitted from the bundle unit 114W.

For example, the bundle unit 114W may bundle optical fibers that transmit white light emitted from a light source (LD or the like). In such a case, a plurality of coherent light sources that emit white light are provided as the plurality of coherent light sources.

Further, the bundle unit 114W may bundle the optical fiber 113R, the optical fiber 113G, and the optical fiber 113B. In such a case, as in the third embodiment, a red coherent light source 111R, a green coherent light source 111G, and a blue coherent light source 111B are provided as a plurality of coherent light sources.

The lens 21 </ b> W is a relay lens that relays white light so that each DMD 500 is irradiated with white light.

[Fourth Embodiment]
Hereinafter, a fourth embodiment will be described with reference to the drawings. In the following, differences from the third embodiment will be mainly described.

Specifically, in the third embodiment, the case where the projection display apparatus 100 projects image light onto the projection plane 300 provided on the wall surface is illustrated. In contrast, the fourth embodiment exemplifies a case in which the projection display apparatus 100 projects image light onto a projection plane 300 provided on the floor (floor projection). The arrangement of the casing 200 in such a case is referred to as a floor projection arrangement.

(Configuration of projection display device)
The configuration of the projection display apparatus according to the fourth embodiment will be described below with reference to the drawings. FIG. 36 is a side view of the projection display apparatus 100 according to the fourth embodiment.

As shown in FIG. 36, the projection display apparatus 100 projects image light onto a projection plane 300 provided on the floor (floor projection). In the fourth embodiment, the first arrangement surface that is substantially parallel to the projection surface 300 is the floor surface 410. A second arrangement surface that is substantially perpendicular to the first arrangement surface is a wall surface 420.

In the fourth embodiment, a horizontal direction parallel to the projection plane 300 is referred to as a “width direction”. The normal direction of the projection plane 300 is referred to as a “height direction”. A direction orthogonal to both the width direction and the height direction is referred to as a “depth direction”.

In the fourth embodiment, the housing 200 has a substantially rectangular parallelepiped shape as in the third embodiment. The size of the housing 200 in the depth direction and the size of the housing 200 in the height direction are smaller than the size of the housing 200 in the width direction. The size of the housing 200 in the height direction is substantially equal to the projection distance from the reflection mirror (concave mirror 152 shown in FIG. 30) to the projection plane 300. In the width direction, the size of the casing 200 is substantially equal to the size of the projection plane 300. In the depth direction, the size of the casing 200 is determined according to the distance from the wall surface 420 to the projection plane 300.

The projection surface side wall 210 is a plate-like member facing a first arrangement surface (in the fourth embodiment, the floor surface 410) substantially parallel to the projection surface 300. The front side wall 220 is a plate-like member provided on the opposite side of the projection plane side wall 210. The top plate 240 is a plate-like member provided on the opposite side of the bottom plate 230. The bottom plate 230 is a plate-like member that faces a second arrangement surface (in the fourth embodiment, a wall surface 420) other than the first arrangement surface substantially parallel to the projection plane 300. The first side wall 250 and the second side wall 260 are plate-like members that form both ends of the housing 200 in the width direction. In the fourth embodiment, a red coherent light source, a green coherent light source, a blue coherent light source, or a white coherent light source may be used.

[Other Embodiments]
As mentioned above, although this invention was described by embodiment, it should not be understood that the description and drawing which form a part of this indication limit this invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

In the embodiment, the case where the number of diffusion surfaces provided on the optical path of the light emitted from the light source unit 110 is one or two is illustrated. However, three diffusion surfaces provided on the optical path of the light emitted from the light source unit 110 may be provided. In such a case, it is only necessary that at least two of the three diffusion surfaces vibrate.

In the embodiment, the case where the light source unit 110 includes the solid light source 111W that emits the white light W is illustrated. However, the embodiment is not limited to this. The light source unit 110 may include a red solid light source that emits red component light R, a green solid light source that emits green component light G, and a blue solid light source that emits blue component light B. In such a case, the diffusion optical element 600 is disposed on each optical path of the red component light R, the green component light G, and the blue component light B.

In the embodiment, the projection display apparatus 100 corresponding to the DLP method (registered trademark) is exemplified. Further, in the embodiment, the projection display apparatus 100 that performs wall surface projection is illustrated. However, the embodiment can be applied to any projection video display apparatus that uses a light source that emits coherent light.

In the first embodiment, the case where the mode is selected according to the distance between the screen and the viewer is illustrated. However, the embodiment is not limited to this. The mode may be selected in accordance with the distance between the screen and the viewer and the detection result by detecting the size of the projected image (degree of zoom), brightness, screen type, and the like.

In the second embodiment, the diffusing optical element 600 is provided on the light exit side of the rod integrator 10W. However, the embodiment is not limited to this. For example, the diffusion optical element 600 may be provided on the light incident side of the rod integrator 10W.

In the second embodiment, the diffusion optical element 600 is illustrated as an example of the uniformizing optical element. However, the embodiment is not limited to this. The homogenizing optical element may be any optical element as long as it makes the spatial distribution of light intensity on the exit pupil plane of the projection unit uniform. For example, the homogenizing optical element may be a diffraction grating or a microlens array. Regarding the diffraction grating, the diffraction pattern (unevenness pattern) of the diffraction grating is designed so that the spatial distribution of the light intensity on the exit pupil plane of the projection unit is made uniform. Regarding the microlens array, the microlens array is designed such that the radius of curvature (R) of the lens in the central region is smaller than the radius of curvature (R) of the lens in the peripheral region. That is, since the radius of curvature (R) of the lens in the central region is small, the light diffusivity increases, and since the radius of curvature of the lens in the peripheral region is large, the light diffusivity decreases.

In the second embodiment, the case where the diffusion optical element 600 has a central region and a peripheral region is illustrated. However, the embodiment is not limited to this. The diffusivity distribution of the diffusing optical element 600 may be designed to make the spatial distribution of the light intensity uniform on the exit pupil plane of the projection unit. For example, the diffusivity of the diffusion optical element 600 may gradually decrease from the center toward the outside.

Further, an area where the intensity of the light emitted from the light source is small (for example, 1 of the maximum intensity), with the area where the intensity of the light emitted from the light source is large (for example, an area larger than ½ of the maximum intensity) as the central area. A region smaller than / 2) may be set as the peripheral region. The size of the central region is preferably smaller than the size of the light exit surface of the rod integrator 10W.

In the third embodiment, the projection plane 300 is provided on the wall surface 420 on which the casing 200 is arranged, but the embodiment is not limited to this. The projection plane 300 may be provided at a position deeper than the wall surface 420 in the direction away from the housing 200.

In the fourth embodiment, the projection plane 300 is provided on the floor surface 410 on which the casing 200 is arranged, but the embodiment is not limited to this. The projection plane 300 may be provided at a position lower than the floor surface 410.

In the embodiment, a DMD (Digital Micromirror Device) is merely exemplified as the light modulation element. The light modulation element may be a transmissive liquid crystal panel or a reflective liquid crystal panel.

In the embodiment, a plurality of DMDs are provided as light modulation elements, but a single DMD may be provided as a light modulation element.

Note that Japanese Patent Application No. 2009-224666 (filed on September 29, 2009), Japanese Patent Application No. 2009-235648 (filed on October 9, 2009), Japanese Patent Application No. 2010-041051 ( The entire contents of Japanese Patent Application No. 2010-042957 (filed on Feb. 26, 2010) are incorporated herein by reference.

According to the present invention, it is possible to provide an optical unit, a projection display apparatus, and a diffusing optical element that can appropriately achieve both speckle noise removal and brightness reduction suppression.

Claims (16)

A projection type comprising: a light source that emits coherent light; a light modulation element that modulates the light emitted from the light source; and a projection unit that projects light emitted from the light modulation element onto a projection plane. A video display device,
A speckle noise reduction element provided between the light source and the light modulation element;
A controller that controls the first mode and the second mode;
The control unit controls the speckle noise reduction element in the first mode so that speckle is reduced more than in the second mode. The speckle noise reduction element is a diffusing optical element that diffuses light emitted from the light source and transmits light emitted from the light source,
2. The control unit according to claim 1, wherein the control unit controls the diffusion optical element so as to diffuse light emitted from the light source in the first mode with a higher diffusivity than in the second mode. The projection-type image display device described. The diffusion optical element has a plurality of diffusion surfaces in the traveling direction of light emitted from the light source,
The projection display apparatus according to claim 2, wherein the control unit controls the diffusion optical element so that the plurality of diffusion surfaces operate with different operation patterns. The diffusion optical element includes a first rotating body that rotates about a first rotating shaft, a second rotating body that rotates about a second rotating shaft that is parallel to the first rotating shaft, the first rotating body, A band-shaped diffusion sheet wound in an endless loop around the second rotating body,
The belt-shaped diffusion sheet constitutes two diffusion surfaces in the traveling direction of the light emitted from the light source,
The said control part controls the said diffusion optical element so that two diffusion surfaces may move to a mutually reverse direction with rotation of a said 1st rotary body and a said 2nd rotary body. The projection type image display device described in 1. 4. The projection type according to claim 3, wherein the control unit controls the diffusion optical element such that when one diffusion surface of the plurality of diffusion surfaces stops, the other diffusion surface moves. 5. Video display device. The diffusion optical element includes a first diffusion plate and a second diffusion plate,
4. The projection display apparatus according to claim 3, wherein the control unit controls the diffusion optical element so that the first diffusion plate and the second diffusion plate vibrate along different directions. The diffusion optical element has a plurality of diffusion regions with different diffusivities,
In the second mode, the control unit controls the diffusing optical element so as to diffuse light emitted from the light source by using a diffusion region having a lower diffusivity than the diffusion region used in the first mode. The projection display apparatus according to claim 2, wherein: A diffusing optical element that diffuses coherent light and transmits coherent light,
A first rotating body that rotates about a first rotation axis;
A second rotating body that rotates about a second rotation axis that is parallel to the first rotation axis;
A belt-shaped diffusion sheet wound in an endless loop around the first rotating body and the second rotating body,
The band-shaped diffusion sheet comprises two diffusion surfaces that move in opposite directions to each other. A relay optical system that relays the light emitted from the light source so that the light emitted from the light source is applied to the light modulation element;
The projection display apparatus according to claim 1, further comprising: a uniformizing optical element that uniformizes a spatial distribution of light intensity on an exit pupil plane of the projection unit as the speckle noise reduction element. The homogenizing optical element is a diffusing optical element that is provided between the light source and the light modulation element and diffuses light emitted from the light source and transmits light emitted from the light source. ,
The diffusion optical element includes a central region including an optical axis center emitted from the light source, and a peripheral region provided around the central region,
The projection display apparatus according to claim 9, wherein a diffusivity of the central region is larger than a diffusivity of the peripheral region. 10. The projection display apparatus according to claim 9, further comprising a control unit that controls the uniformizing optical element to operate in a predetermined operation pattern. A diffusion optical element having a diffusion region that diffuses coherent light and transmits coherent light,
The diffusion region includes a central region including an optical axis center of coherent light, and a peripheral region provided around the central region,
The diffusion optical element according to claim 1, wherein a diffusion degree of the central region is larger than that of the peripheral region. A pair of lens arrays;
Vibration applying means for periodically moving the pair of lens arrays;
An optical unit comprising: The pair of lens arrays includes:
A first lens array having a focal length f and a second lens array having a focal length f ′;
The focal length f and the focal length f ′ satisfy f ≦ f ′,
When a medium having an absolute refractive index n is interposed between the first lens array and the second lens array, the first lens array and the second lens array are approximately (f + f ′). An optical unit characterized by being arranged with an interval of / n. The speckle noise reduction element is an optical unit that periodically moves so that light emitted from the light source passes through,
The projection image display apparatus according to claim 1, wherein the optical unit includes a pair of lens arrays. When the divergence angle of light incident on the optical unit is θ,
The lens diameter d and the focal length f of each lens are set so that a lens array arranged at least on the incident side of the pair of lens arrays satisfies a condition of tan θ <d / 4f. Item 15. A projection display apparatus according to Item 14.

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