KR101133134B1 - Alignment apparatus of light axis and Micro projector comprising the same - Google Patents

Abstract

A first moving part movable in a first axial direction with respect to a housing in which the micro fly's eye lens is accommodated, for easily and firmly aligning the position of the optical axis of the focusing lens with respect to the micro fly's eye lens in the micro projector; And a second moving part accommodating a focusing lens, the second moving part coupled to the first moving part to be movable in a second axial direction perpendicular to the first axial direction. It provides a micro projector provided with.

Description

Alignment apparatus of light axis and Micro projector comprising the same

1 is a schematic perspective view of a micro projector according to an embodiment of the present invention.

FIG. 2 is a schematic layout view of an optical system viewed from the side of the micro projector shown in FIG. 1.

3 is a perspective view illustrating an optical axis alignment device of the micro-projector shown in FIG. 1.

4 is an exploded perspective view of the optical axis aligning device shown in FIG. 3.

5 is a view from above of the optical axis aligning device coupled to the housing;

FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 5.

FIG. 7 is a cross-sectional view taken along the line VIII-VIII of FIG. 5.

8 is a cross-sectional view illustrating an optical axis alignment device of a micro projector according to another embodiment of the present invention.

9 is a view from above of an optical axis alignment device coupled to a housing according to another embodiment of the present invention.

FIG. 10 is a diagram showing a path of a light beam passing through the homogenizing means of the micro projector shown in FIG.

11A is a diagram showing a traveling direction and a polarization direction of a light beam incident on a PBS (Polarizing Beam Splitter) and an image display panel.

FIG. 11B is a diagram illustrating a traveling direction and a polarization direction of the light beam incident in FIG. 11A when the pixel is in a black state in the image display panel.

FIG. 11C is a diagram illustrating a traveling direction and a polarization direction of the light beam incident in FIG. 11A when the pixel is in a white state in the image display panel.

Brief description of symbols for the main parts of the drawings

1: Micro projector 2: Menu button

3: exit port 10: projection optical system

20: illumination optical system 21, 22, 23: G light source, R light source, B light source

24, 25, 26: first, second, third focusing lens

27, 28, 29: 1st, 2nd, 3rd mirror 30: (lambda) / 2 filter

31: reflective mirror 32: micro fly eye lens

33: fourth focusing lens 34: collimation lens

35: homogenization means 36: polarizing beam splitter (PBS)

40: screen display panel 60: housing

70: optical axis alignment device 71, 171: first moving part

71c: first leaf spring 71e, 171e: pressure guide

72: second moving part 72b: second leaf spring

73: 1st axis adjustment bolt 74: 2nd axis adjustment bolt

76: ring spring 77: 1st axis fixing bolt

The present invention relates to an optical axis alignment device and a micro projector having the same, and more particularly, light beams from a laser light source of a micro projector that is connected to a portable multimedia device to enlarge and display an image on an external screen. The present invention relates to an optical axis alignment device for aligning an optical axis to be accurately incident on a panel, and a micro projector having the same.

Projectors are classified into reflective projectors and projection projectors according to whether the light beams reflect or transmit through the image display panel. In addition, the projector may be classified into a single plate type, two plate type, and three plate type projectors according to the number of image display panels used. In addition, according to the type of light source may be divided into a projector using a lamp light source and a projector using a laser light source.

Projectors using lamp light sources are quite large and difficult to carry. In order to overcome this problem, the development of a projector using a laser light source has been progressed in recent years.

Recently, portable multimedia devices such as digital cameras, digital camcorders, portable media players (PMPs), PSPs, laptop computers and mobile phones have been widely used. As the utilization of such portable multimedia devices increases, the cases of sharing with other people are increasing. In particular, since the portable multimedia device has good mobility, the portability and mobility of the projector should also be good to increase the utilization of the portable multimedia device. Therefore, the necessity for the projector to be manufactured so small that it can be stored in the pocket to increase the portability is increasing.

A micro-projector using a laser light source largely consists of an illumination optical system, an image display panel, and a projection optical system. The illumination optical system serves to incident light beams from the G, R, and B laser light sources accurately onto the image display panel with a uniform light intensity distribution. In particular, in order to accurately enter the light beams with uniform light intensity into the image display panel, there is a need to accurately align the optical axis of the light beams passing through the uniforming means during assembly.

The present invention provides an optical axis alignment device and a micro projector having the same, which can easily align an optical axis between two lenses so that the light beams from the laser light sources of the micro projector can be incident on the image display panel with a uniform light intensity distribution. The purpose is to provide.

The present invention includes a first moving part movable in a first axial direction with respect to a housing in which the first lens is accommodated; And a second moving part accommodating a second lens and coupled to the first moving part to be movable in a second axial direction orthogonal to the first axial direction.

The optical axis alignment device includes: a first shaft adjusting bolt that penetrates the first moving part and adjusts the first axial displacement of the first moving part with respect to the housing by adjusting the amount of penetration; And a second shaft adjusting bolt penetrating the second moving part and adjusting the second axial displacement of the second moving part with respect to the first moving part by adjusting the amount of penetration.

In addition, the optical axis alignment device is coupled to the opposite side of the first axis adjustment bolt side of the first moving portion, the first leaf spring for providing an elastic force for pressing the housing to the first axis adjustment bolt side; And a second leaf spring coupled to an opposite side of the second shaft adjusting bolt side of the second moving part and providing an elastic force for pressing the first moving part toward the second shaft adjusting bolt side.

By the above configuration, it is possible to easily align the optical axis of the second lens with respect to the first lens by adjusting the penetration amount of the first axis adjustment bolt and the second axis adjustment bolt.

The optical axis alignment device may further include a first shaft fixing bolt configured to penetrate the housing and the first moving part in the second axial direction to fix a first axial displacement with respect to the housing of the first moving part. In addition, after the alignment is completed, each fastening portion of the first shaft adjustment bolt and the second shaft adjustment bolt can be bonded (bonding). In this way, the optical axis can be firmly aligned without misalignment.

Four pressure guides formed to protrude in four corner regions of the first moving part are fitted into the holes formed in the second moving part and bent outwards so that the first moving part is closely attached to the second moving part.

The optical axis aligning device is elastically fitted between the second moving parts and the portions of the pressing guides which are inserted into the second moving parts and protrude, and moves the first moving parts in the protruding direction of the pressing guides. The display device may further include a ring spring that closely contacts the first moving part and the second moving part. The distance between the first moving part and the second moving part in the third axial direction orthogonal to both the first axial direction and the second axial direction may be firmly fixed by the ring spring and the pressure guide.

In addition, according to another aspect of the invention, the light source is arranged in a row so that the exit port for emitting the laser light beam of G, R, B is directed downward, disposed below the respective light sources and the First to third focusing lenses for adjusting width, first to third mirrors disposed below the first to third focusing lenses and reflecting about 90 degrees so that the light beams are directed backward, the reflected light A reflection mirror for reflecting the beams upwards about 90 degrees, equalizing means for equalizing the light intensity distribution of each of the upwardly directed light beams, and reflecting about 90 degrees so that only the polarization in a predetermined direction of the uniformed light beams is directed backwards An illumination optical system including a PBS, and an optical axis alignment device according to any one of claims 1 to 7; An image display panel which modulates G, R, and B light beams from the illumination optical system according to an image signal to form an image, and reflects the modulated light beams by 180 degrees; And a projection optical system including a plurality of lenses arranged in a line such that the light beam forming the image is projected onto an external screen.

Hereinafter, embodiments of the present invention shown in the accompanying drawings will be described in detail.

1 is a schematic perspective view of a micro projector according to an embodiment of the present invention. The micro-projector is generally in the shape of a cube, and an exit port through which the light beam is emitted to the external screen is disposed above the front of the projector. And menu buttons for operating the projector are arranged on the top of the projector. Although not shown in the drawing, an input port for receiving an image signal from a portable multimedia device is disposed at the rear of the micro projector.

FIG. 2 is a schematic layout view of an optical system viewed from the side of the micro projector shown in FIG. 1. Referring to FIG. 2, the optical system of the micro-projector is largely composed of an illumination optical system and a projection optical system. The illumination optical system 20 includes a G light source 21, an R light source 22, a B light source 23, first to third focusing lenses 24, 25 and 26, and first to third mirrors 27 and 28. 29, reflecting mirror 31, homogenizing means 32, 33, 34, polarizing beam splitter (PBS) 36, and image display panel 40. The projection optical system 10 includes a series of lenses through which a light beam exiting the image display panel 40 passes.

The light source has a G light source 21, an R light source 22, and a B light source 23 as a laser light source. The G light source 21 according to an embodiment of the present invention is a diode pumping solid state laser (DPSS), and the R light source 22 and the B light source 23 are laser diodes (LDs). LD and DPSS have the advantage of being smaller than other laser light sources. The G light beam coming out of the DPSS has a good straightness compared to the R and B light beams coming out of the LD, so that the light beam has a smaller width. In order to adjust the widths of the G, R, and B light beams to a predetermined size, the first, second, and third focusing lenses 24, 25, and 26 may be configured by the G, R, and B light sources 21, 22, and 23. It is placed at the bottom.

At this time, the respective light sources are arranged far from the homogenizing means 35 in the order of the G light source 21, the R light source 22, and the B light source 23. That is, the G light source 21 is disposed farthest from the homogenizing means 35. This is to ensure a sufficient travel distance to widen the width of the relatively narrow G light beam to a predetermined size using the first focusing lens 24. In consideration of the widths of the R light beam and the B light beam, since the traveling distance of the R light beam must be larger than the traveling distance of the B light beam, the R light source 22 is disposed farther from the equalizing means than the B light source 23. . However, it is to be understood that the arrangement of the respective light sources is not necessarily limited thereto, and the arrangement may be changed according to the type of light source to be adopted.

First to third mirrors 27, 28, and 29 are disposed below the first to third focusing lenses 24, 25, and 26, respectively. The first mirror 27 reflects the G light beam counterclockwise by about 90 degrees. That is, the G light beam that has been directed downward is directed backward. The second mirror 28 is a dichroic mirror that reflects the R light beam backward by about 90 degrees and transmits light beams other than the R light beam. The third mirror 29 is a dichroic mirror, which reflects the B light beam backward by about 90 degrees and transmits light beams other than the B light beam. As a result, the G light beams, R light beams, and B light beams from the G light source 21, the R light source 22, and the B light source 23 all travel toward the reflection mirror 31.

Types of the first to third mirrors 27, 28, and 29 may be changed according to the arrangement of the respective light sources. For example, if each light source is disposed away from the homogenizing means 35 in the order of the R light source, the B light source, and the G light source, a first mirror for reflecting the R light beam is disposed below the R light source, and the B light source is disposed. A dichroic mirror that reflects only the B light beam and transmits the remaining light beams will be disposed below, and a dichroic mirror that reflects only the G light beam and transmits the remaining light beams will be disposed below the G light source.

As shown in FIG. 6, the first mirror 27, the second mirror 28, the third mirror 29, and the reflection mirror 31 are accommodated in the seating part of the housing 61, and the housing 61. By the contact portion and the holder of the leaf spring 65 covering the lower portion of the) it can be fixed uniformly and firmly to the housing (61).

The G light source 21 has a substantially circular shape and is polarized light which vibrates in the vertical direction in a cross section perpendicular to the advancing direction. The R light source 22 has an elliptical shape and is polarized light that vibrates in the vertical direction in a cross section perpendicular to the advancing direction. The B light source 23 has an elliptical shape and is polarized light that vibrates in left and right directions in a cross section perpendicular to the advancing direction.

However, as shown in FIG. 10, in order to reduce the light loss in the PBS 36, the polarization of the light beam incident on the micro fly's eye lens 32 should be the polarization oscillating in the vertical direction in a cross section perpendicular to the traveling direction. do. Therefore, it is necessary to convert the polarization of the B light beam in the left and right directions to the polarization in the vertical direction. For this purpose, a λ / 2 filter (half wave plate) 30 is disposed below the B light source 23. Thereby, the polarization of the G light beam, the R light beam, and the B light beam is all the polarization in the vertical direction in the cross section perpendicular to the traveling direction, so that the light loss in the PBS 36 can be reduced.

The G light source 21, the R light source 22, and the B light source 23 operate in conjunction with an output signal of a controller, which will be described later, in accordance with an image signal input through an input channel from the outside. That is, the G light beam, the R light beam, and the B light beam are emitted from the G light source 21, the R light source 22, and the B light source 23 by the output signal of the controller.

The reflective mirror 31 refracts the G light beam, the R light beam, and the B light beam counterclockwise by about 90 degrees emitted from each light source and reflected on each of the first to third mirrors 27, 28, and 29. Let's do it. In other words, each light beam directed backward is directed upward. At this time, the reflection mirror 31 is a mirror that reflects all of the G light beam, the R light beam, and the B light beam. Each light beam reflected by the reflection mirror 31 is incident on the equalizing means 35.

FIG. 10 is a diagram showing the equalization means 35 and the path of the light beam passing through the equalization means 35 according to an embodiment of the present invention. As an embodiment of the homogenizing means 35 a micro fly-eye lens 32, a fourth focusing lens 33 and a collimation lens 34 are used. The micro fly's eye lens 32 is disposed above the reflection mirror 31, the fourth focusing lens 33 is disposed above the micro fly's eye lens 32, and the collimation lens 34 is the fourth focusing lens. It is arrange | positioned above 33.

Each light beam must be accurately incident on the entire effective area of the micro fly's eye lens 32. This can be achieved by adjusting the focusing lenses 24, 25, 26 disposed below each light source.

The light intensity distribution of the light beam incident on the micro fly's eye lens 32 is large at the center and small at the periphery as shown in FIG. 7. The incident light beam is split by the micro fly's eye lens 32. Each divided light beam is incident across the collimation lens 34 while passing through the fourth focusing lens 33. That is, since the light beams split at the center and both peripheral parts are all incident through the collimation lens 34 by the fourth focusing lens 33, the light intensity distribution of the light beams passing through the collimation lens 34 as a whole. Become uniform. Therefore, the light intensity distribution of the light beam incident on the PBS 36 becomes uniform. Then, the light beams of uniform light intensity enter the image display panel 40 via the PBS 36.

However, in order to uniformize the light intensity of the light beam and to accurately enter the image display panel 40, the fourth focusing lens 33 should be exactly aligned with the micro fly's eye lens 32. Therefore, an optical axis alignment device 70 is used that can align the fourth focusing lens 33 with respect to the micro fly's eye lens 32 when assembling the micro projector 1.

The first lens (which is a micro fly's eye lens 32 in one embodiment of the invention) is inserted into and fixed to the dichroic mirror holding structure 60. The optical axis alignment device 70 is coupled to the dichroic mirror holding structure 60 into which the first lens is inserted.

Hereinafter, the optical axis alignment device 70 will be described in detail.

3 is a perspective view illustrating an optical axis aligning device of the micro-projector shown in FIG. 1, and FIG. 4 is an exploded perspective view of the optical axis aligning device shown in FIG. 3. 5 is a cross-sectional view taken along the line VI-VI of FIG. 5, and FIG. 7 is a cross-sectional view taken along the line VIII-V of FIG. 5. .

Optical axis alignment device 70 according to an embodiment of the present invention is the first moving part 71, the second moving part 72, the first axis adjusting bolt 73, the second axis adjusting bolt 74, the first The first leaf spring 71c, the second leaf spring 72b, the first shaft fixing bolt 77, and the ring spring 76 are included.

The first moving part 71 is coupled to the housing 60 of the dichroic mirror holding structure. The first moving part 71 is a square plate, and a first guide 71a, a second guide 71b, a first leaf spring 71c, and a third guide 71d are formed on each side of the plate. It is. Since the first guide 71a, the second guide 71b, the first leaf spring 71c, and the third guide 71d protrude from the plate toward the housing 60, the first moving part 71 is It may be coupled to the housing 60. In addition, pressure guides 71e are formed to protrude toward the second moving part 72 on the side surface of the second moving part 72 of the first moving part 71.

The hole is formed in the 1st guide 71a of the 1st moving part 71, and the screw tab is formed in the hole. The first shaft adjusting bolt 73 is fitted through the hole of the first guide 71a. A first leaf spring 71c is formed on the side opposite to the first axis adjustment bolt 73 side of the first moving part 71. The first leaf spring 71c is configured to press the housing 60 toward the first guide 71a by an elastic force.

By the above structure, when the amount of penetration of the first guide 71a of the first shaft adjustment bolt 73 increases, the first shaft adjustment bolt 73 pushes the housing 60 toward the first leaf spring 71c. As a result, the first moving part 71 moves in the negative direction of the first axis with respect to the housing 60. On the contrary, when the penetration amount of the first guide 71a of the first shaft adjustment bolt 73 is reduced, the housing 60 is pushed toward the first guide 71a by the restoring force of the first leaf spring 71c. As a result, the first moving part 71 moves in the positive direction of the first axis.

The second moving part 72 is formed of a square plate, and holes are formed in the second moving part 72 to correspond to the pressing guides 71e of the first moving part. The first moving part 71 is engaged with the second moving part 72 by fitting the pressure guide 71e of the first moving part to the hole of the second moving part 72. However, since the length of the pressing guide 71e in the second axial direction is smaller than the length of the hole, the first moving part 71 is movably coupled to the second moving part 72 in the second axial direction.

In each pressing guide 71e, a ring spring 76 is elastically fitted between the protruding portion of the second moving part 72 and the second moving part 72. The ring spring 76 provides an elastic force that tries to open outward. Then, the width (length in the second axial direction) of the pressing guides increases as the distance from the first moving part 71 (moves in the positive direction in the third axis). Thus, the ring spring 76 is sandwiched between the four pressing guides to provide an elastic force so that the first moving portion 71 having the pressing guide is in close contact with the second moving portion 72. That is, the first moving part 71 and the second moving part 72 are fixed to each other in the third axial direction by the action of the ring spring 76 and the pressure guide, and thus do not shake.

8 and 9 are a perspective view and a cross-sectional view of an optical axis alignment device according to another embodiment. The second moving part 72 is formed of a square plate, and holes are formed in the second moving part 72 to correspond to the pressing guides 71e of the first moving part. After the pressing guide 171e of the first moving part is fitted into the hole of the second moving part 72, each pressing guide 171e is bent outward. As a result, the second moving unit 72 is coupled while being in close contact with the first moving unit 171. However, since the length of the pressing guide 171e in the second axial direction is smaller than the length of the hole, the first moving part 171 is movably coupled to the second moving part 72 in the second axial direction. That is, it is possible to couple the first moving part 71 and the second moving part 72 in close contact without the ring spring 76.

The fourth moving lens 33, which is the second lens 33, is supported by the second moving unit 72. To this end, the second lens 33 is fixed to the hole formed in the center of the second moving unit 72 through the lens barrel 75.

The hole is formed in the 1st guide 72a of the 2nd moving part 72, and the screw tab is formed in the hole. The second shaft adjustment bolt 74 is fitted through the hole of the first guide 72a. A second leaf spring 72b is formed on the opposite side of the second shaft adjustment bolt 74 side of the second moving part 72. The second leaf spring 72b is configured to press the housing 60 toward the first guide 72a by an elastic force.

By the above configuration, when the penetration amount of the first guide 72a of the second shaft adjustment bolt 74 is increased, the second shaft adjustment bolt 74 pushes the housing 60 toward the second plate spring 72b. As a result, the second moving part 72 moves in the positive direction of the second axis with respect to the housing 60. On the contrary, when the penetration amount of the first guide 72a of the second shaft adjustment bolt 74 is reduced, the housing 60 is pushed toward the first guide 72a by the restoring force of the second leaf spring 72b. As a result, the second moving unit 72 moves in the negative direction of the second axis.

In summary, when the penetration amount of the first shaft adjusting bolt 73 is adjusted, the first moving part 71 and the second moving part 72 move in the first axial direction with respect to the housing 60. When the penetration amount of the two-axis adjustment bolt 74 is adjusted, the second moving part 72 moves in the second axial direction with respect to the first moving part 71. Therefore, the second lens fixed to the second moving part 72 by appropriately adjusting the penetration amount of the first shaft adjusting bolt 73 and the second shaft adjusting bolt 74 is the first lens fixed to the housing 60. It can be aligned in the first axial direction and the second axial direction with respect to (32). As a result, optical axis alignment is possible in the first axis direction and the second axis direction.

On the other hand, the alignment in the second axial direction is preferably performed after the alignment in the first axial direction is completed. Therefore, it is necessary to prevent the alignment from shaking after the alignment in the first axial direction is completed. To this end, the first shaft fixing bolt 77 is simultaneously fastened through the housing 60 and the second guide 71b of the first moving part. As a result, the first moving part 71 no longer moves in the first axial direction with respect to the housing 60. In addition, the fastening portion (not shown) may be bonded to prevent the first shaft fixing bolt 77 from being pulled out.

As such, after the optical axis alignment is completed between the first lens 32 and the second lens 33, it is preferable to permanently fix the optical axis alignment device 70. To this end, the fastening portions of each of the first shaft adjusting bolt 73 and the second shaft adjusting bolt 74 may be bonded.

The optical axis alignment device 70 as described above is performed when assembling the illumination optical system 20 of the micro projector. That is, whether the light beam exiting the laser light sources 21, 22, and 23 and passed through the micro fly's eye lens 32 is split into a uniform light intensity distribution while passing through the uniforming means and is incident on the image display panel 40 accurately. While checking, the optical axis is aligned by adjusting the penetration amount of the first axis adjusting bolt 73 and the second axis adjusting bolt 74. After the alignment is completed, the optical axis is fixed by bonding the respective fastening portions. Therefore, the optical axes can be aligned so that the light beams can be split into a uniform light intensity distribution so as to accurately enter the image display panel 40.

In the present invention, the homogenizing means 35 is provided with a micro fly's eye lens 32, but may be provided with a DOE (diffraction optical element) (not shown).

The image display panel 40 serves to form an image by modulating a light beam according to an image signal input from the outside. As an example of the image display panel 40, a digital micromirror display (DMD) panel, an LCD panel, a liquid crystal on silicon (LCoS) panel, a diffractive optical display element, or the like can be used. The image display panel 40 according to an embodiment of the present invention is an LCoS panel.

Although not shown in the figure, an LCoS panel includes indium tin oxide glass, liquid crystal, aluminum pixels, and a CMOS substrate. Light incident through the ITO glass may be reflected by rotating the polarization direction by 90 degrees according to the molecular arrangement of the liquid crystal of each pixel, or may be reflected by keeping the polarization direction. The molecular arrangement of the liquid crystal is controlled according to the voltage applied to the electrodes of each pixel through the CMOS substrate. That is, the controller applies a voltage to a specific pixel in response to an image signal input from the outside, and the polarization direction of the light beam is controlled by changing the molecular arrangement of the liquid crystal corresponding to the specific pixel according to whether the voltage is applied.

Unlike the transmissive LCD, the LCoS panel 40 reflects the light beam incident through the liquid crystal and exits again. In other words, the aperture ratio is high because it does not transmit through CMOS. Therefore, the LCoS panel 40 has a higher light transmittance and a higher luminance than a transmissive LCD.

Referring to Figs. 11A to 11C, an operation principle in which the PBS 36 and the image display panel 40 advance each light beam from the homogenizing means 35 to the projection optical system 10 will be described. As shown in Fig. 11A, each of the light beams having uniform light intensity and polarized light oscillating in the vertical direction in the cross section perpendicular to the advancing direction is incident on the PBS 36. The PBS 36 has only about 90 degrees of polarized light oscillating in a predetermined direction among the light beams emitted through the homogenizing means 35 and in the vertical direction in the cross section perpendicular to the traveling direction of the light beam in the embodiment of the present invention. Reflect in the direction. That is, only the polarization oscillating in the vertical direction is directed backward, and the remaining polarization is transmitted. The polarized light vibrating in the reflected vertical direction is incident on the image display panel 40.

As shown in FIG. 11B, a light beam incident on a black state pixel among pixels of the image display panel 40 is reflected on the image display panel 40 while maintaining the same polarization direction. . As a result, since the light is reflected back to the PBS 36, the light beam does not proceed toward the projection optical system 10. Therefore, G, R, and B light are not formed in the external screen corresponding to the pixel in the dark state.

As shown in FIG. 11C, the light beam incident on the white state pixel among the pixels of the image display panel 40 is reflected on the image display panel 40 with the polarization direction rotated by 90 degrees. Comes out. As a result, since the reflected light beam is polarized light oscillating in the left and right direction in the cross section perpendicular to the traveling direction, the light beam passes through the PBS 36 and travels toward the projection optical system 10. Therefore, G, R, and B light are formed on the external screen corresponding to the pixel in the bright state.

In this case, the pixel to which the voltage is applied may be set to a bright state. Alternatively, the pixel to which the voltage is applied may be set to a dark state.

On the other hand, the light beam that has passed through the homogenizing means 35 should be incident perpendicularly to the incident surface 36a of the PBS 36 in principle. However, in reality, a skew ray that is not perpendicular to the incident surface 36a is generated, and the skew ray is reflected from the reflective surface 36b of the PBS 36 with the polarization direction slightly rotated. To correct this, a λ / 4 filter 37 may be additionally disposed in the light beam path between the PBS 36 and the image display panel 40.

In addition, a polarizer 38 may be additionally disposed between the PBS 36 and the projection optical system 10. The polarizer 38 passes only the polarization oscillating in the left and right directions in the cross section perpendicular to the traveling direction of the light beam. That is, it filters out polarization other than desired polarization. Thus, the λ / 4 filter 37 and / or polarizer 38 improves the contrast of the image.

Up to now, although the reflective image display panel 40 has been described as the image display panel 40, a transmissive image display panel, for example, a transmissive LCD panel, may be used as another embodiment of the present invention.

The micro-projector 1 according to an embodiment of the present invention further includes a control unit (not shown) and a heat dissipation unit 50 in addition to the illumination optical system 20 and the projection optical system 10. The controller controls the operations of the G light source 21, the R light source 22, and the B light source 23 according to the image signal input from the outside, and controls the operation of the image display panel 40. The heat dissipation unit 50 serves to discharge heat generated by the G light source 21, the R light source 22, and the B light source 23. To this end, the heat dissipation unit is configured to surround the G light source 21, the R light source 22, and the B light source 23, and heat dissipation fins are provided on the surface of the heat dissipation unit to increase the heat dissipation area.

Next, a process of magnifying and projecting an image on an external screen by the micro-projector 1 according to an exemplary embodiment of the present invention will be described.

When the micro projector 1 is connected to an external multimedia device through its input port, an image signal from the multimedia device is input to the controller 50 of the micro projector. The controller 50 controls the image display panel 40 according to the input image signal. Then, the arrangement of the liquid crystals 42 corresponding to the specific pixels to be operated to form the image is changed. On the other hand, the G light source 21, the R light source 22, and the B light source 23 are operated in conjunction with the image display panel 40 by the controller 50, and the G light from each light source 21, 22, 23 is operated. The beam, the R light beam, and the B light beam are sequentially emitted.

Each light beam passes through the first to third focusing lenses 24, 25, 26, respectively, and is reflected by the first to third mirrors 27, 28, 29, respectively, and is incident on the reflection mirror 31. Each light beam reflected by the reflection mirror 31 has a uniform light intensity by the homogenizing means 35. Each light beam having a uniform light intensity is reflected from the PBS 36 to polarized light in a predetermined direction and is incident on the reflective image display panel 40 such as LCoS.

The light beams incident on the specific cells according to the image signal in the LCoS 40 are reflected in the opposite directions with the polarization direction rotated by 90 degrees, passing through the PBS 36, and incident on the projection optical system 10. Each incident light beam is magnified while passing through the projection optical system 10, thereby projecting the magnified image onto the external screen. At this time, the G light beam, the R light beam, and the B light beam are sequentially projected on the external screen in a very short time. That is, G images, R images, and B images are sequentially projected on the external screen at extremely short time intervals. As a result, the projected R image, G image, and B image are superimposed to form one image. In addition, a moving image is formed by successively projecting each image thus formed.

The micro-projector of the present invention employs an optical axis alignment device, wherein the optical axis alignment device has a first axis direction and a second axis direction with respect to the micro fly's eye lens as a first axis adjusting bolt and a second axis adjusting bolt when the illumination optical system is assembled. By adjusting the position of the fourth focusing lens, the optical axis between the two lenses can be simply and firmly aligned.

Therefore, a good image can be obtained by injecting the light beams from the laser light sources accurately into the image display panel with uniform light intensity distribution.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (10)

A first moving part movable in a first axial direction with respect to a housing in which the first lens is accommodated; And A second moving part accommodating a second lens and coupled to the first moving part to be movable in a second axial direction perpendicular to the first axial direction; And And a pressure guide formed to protrude in four corner regions of the first moving part and fitted into a hole formed in the second moving part to couple the first moving part to the second moving part. The method according to claim 1, A first axial adjustment bolt penetrating the first moving part and adjusting the first axial displacement of the first moving part with respect to the housing by adjusting the amount of penetration; And And a second axis adjusting bolt that penetrates the second moving part and adjusts the second axial displacement of the second moving part with respect to the first moving part by adjusting the penetrating amount. The method of claim 2, A first leaf spring coupled to an opposite side of the first shaft adjustment bolt side of the first moving part and providing an elastic force for pressing the housing toward the first shaft adjustment bolt side; And And a second leaf spring coupled to an opposite side of the second axis adjusting bolt side of the second moving part and providing an elastic force for pressing the first moving part toward the second axis adjusting bolt side. Claim 4 was abandoned when the registration fee was paid. The method of claim 2, And a first shaft fixing bolt for fixing a first axial displacement with respect to the housing of the first moving part through the housing and the first moving part in the second axial direction. delete The method according to claim 1, The length of the pressing guide in the second axial direction is larger as it moves away from the first moving part, The first moving part and the first moving part are elastically fitted between the second moving part and the portion of the pressing guides which are inserted into the second moving part and protrude. The optical axis aligning device further comprises a ring spring for bringing the second moving part into close contact. Claim 7 was abandoned upon payment of a set-up fee. The method according to claim 1, Light sources arranged in a row such that the exit holes emitting the G, R, and B laser beams face downward, and first to third focusing lenses disposed below the respective light sources and adjusting the widths of the respective light beams. For example, first to third dichroic mirrors disposed below the first to third focusing lenses and reflecting the light beams 90 degrees toward the rear, and the 90 degree reflections so that the reflected light beams face upwards. A reflecting mirror, a homogenizing means for equalizing the light intensity distribution of each of the upwardly directed light beams, a PBS for reflecting 90 degrees so that only polarization in a predetermined direction of the uniformed light beams is directed backwards, and claim 1 to claim 4 An illumination optical system comprising the optical axis alignment device of any one of claims 6 and 7; An image display panel which modulates G, R, and B light beams from the illumination optical system according to an image signal to form an image, and reflects the modulated light beams by 180 degrees; And And a projection optical system including a plurality of lenses arranged in a line such that the light beam forming the image is projected onto an external screen. Claim 9 was abandoned upon payment of a set-up fee. The method of claim 8, And the image display panel is a liquid crystal on silicon (LCoS). Claim 10 was abandoned upon payment of a setup registration fee. The method of claim 8, wherein the uniforming means, A micro fly-eye lens disposed on an optical beam path between the reflective mirror and the PBS, the micro fly-eye lens splitting the respective G, R, and B light beams reflected by the reflective mirror; And A fourth focusing lens and a collimation lens disposed on a light beam path between the micro fly's eye lens and the PBS and condensing the split light beam to equalize the light intensity distribution of the light beam incident on the PBS; Micro projector.

Images