WO2018086349A1 - 3d projection lens and projection apparatus - Google Patents

Abstract

A 3D projection apparatus comprises a light source (301), a color separation and color combination unit, a light modulation unit (401), and a 3D projection lens (308). The 3D projection lens (308) comprises a front lens unit (402), a light splitting unit, a back lens unit, and a liquid crystal component (409). A light splitting portion of the light splitting unit is positioned at an aperture stop (407) of the 3D projection lens (308). The light source (301) emits a beam towards the color separation and color combination unit, which guides the beam to the light modulation unit (401). The light modulation unit (401) modulates the beam from the color separation and color combination unit to form an image light and emits the image light to the 3D projection lens (308). The 3D projection lens (308) receives the image light from the light modulation unit (401) and splits the image light into a first light and a second light, and projects the first light and the second light to a screen (408), wherein the first light and the second light are superimposed to present a 3D effect. By implementing a 3D system in a projection lens, the volume of the 3D system is reduced, thus minimizing the volume of the light splitting unit, avoiding an excessive length from a light modulator to the projection lens and lowering design complexity of lenses.

Description

 3D projection lens and projection device Technical field

The present application relates to the field of optical technologies, and in particular, to a 3D projection lens and a projection device.

Background technique

The 3D projection display is more and more widely used for its vivid and three-dimensional display effect. In order to achieve 3D effects, projectors commonly used in theaters require special 3D devices. Currently, 3D devices can convert the image light of natural light properties into linearly polarized light by using a polarizer, and then linearly polarize the light through a time-modulated liquid crystal device. The left-handed circularly polarized light and the right-handed circularly polarized light are converted into time series, and the left-handed circularly polarized light and the right-handed circularly polarized light are left-eye image light and right-eye image light, respectively, and the two are superimposed to achieve a 3D effect. In this process, natural light passes through the polarizer and loses half of the light, and then a part of the light is lost through the liquid crystal device, thereby causing the overall light efficiency of the projector to be relatively low.

technical problem

In order to reduce the light loss of the 3D device at the polarizer position, the person in the field developed a dual optical path 3D system, so that the natural light attribute image light passes through the PBS (polarization beam). Splitter, polarizing beam splitting prism) The prism is divided into S light and P light, S light is transmitted, P light is reflected, and the reflected P light is converted into S light by the polarization converter, and the two S lights are turned into a time-lapse left-handed circularly polarized light through the liquid crystal device. And right-handed circularly polarized light, which is finally synthesized on the screen as left-eye image light and right-eye image light. However, since the lens design needs to consider the versatility of the lens, the PBS is usually disposed behind the lens as an additional device. Such a design will result in inefficient beam splitting through the PBS prism, and the volume of the PBS prism needs to be made larger. The manufacturing cost is too high.

There is also a prior art, such as the projection lens of CN102402018A, as shown in FIG. 1, the light modulated by the digital micromirror device 301 is emitted through the Philips prism and the TIR prism, and is unpolarized light, and the unpolarized light passes through Following the mirror group 31, the image is relayed in the polarization conversion system 32 and converted into polarized light by the polarization conversion system 32, and the rear projection lens 33 images the relay image onto the screen, thereby realizing a 3D effect. In this technical solution, the polarization conversion system 32 is placed in front of the lens, so that the distance of the digital micromirror device 301 to the lens is longer, that is, the BFL of the lens (back Focal Length) makes the lens more difficult to design and process. At the same time, the PBS prism 304 is placed in the intermediate optical path of the outgoing beam of the digital micromirror device 301. Since the beam is in a diverging state, the volume of the PBS prism 304 must also be designed to be large, and the overall structure is also complicated.

Technical solution

According to an aspect of the present invention, a 3D projection lens includes a front group lens unit, a beam splitting unit, and a rear group lens unit, the rear group lens unit including at least a first rear group lens and a second rear group lens; The front group lens unit receives image light and condenses the image light to the beam splitting unit; a portion of the beam splitting unit for splitting light is disposed at an aperture stop position of the 3D projection lens; the light splitting unit receives the Image light of the front group lens unit, splitting the image light to obtain a plurality of beams, the plurality of beams including at least first light and second light of different propagation directions; and the beam splitting unit to align the first light along the first light Leading to the first rear group lens, guiding the second light along the second optical path to the second rear group lens; the first rear group lens and the second rear group lens are respectively in the An optical path and a second optical path; the first rear group lens receives the first light, and the second rear group lens receives the second light and exits.

Preferably, the light splitting unit is arranged such that the beam cross-sectional area of the image light at the beam splitting unit is less than or equal to the aperture stop cross-sectional area.

Preferably, the second rear group lens has a certain optical axis offset with respect to the first rear group lens, such that the first light emitted by the first rear group lens and the second light emitted by the second rear group lens overlap on the screen. .

Preferably, the beam splitting unit comprises a polarization beam splitting prism disposed at an aperture stop position of the 3D projection lens for splitting the incident image light into a first light having a first polarization state and a second light polarization state The two-light projection lens further includes a polarization conversion component on the first optical path or the second optical path for converting the first light into the second polarization state or converting the second light into the first polarization a state such that the first light incident to the first rear group lens and the second light incident to the second rear group lens have the same polarization state.

Preferably, the beam splitting unit further comprises a mirror; the mirror is at a second optical path, the polarizing beam splitting prism transmits the first light to the first rear group lens, the second light is reflected to the mirror, and the mirror receives the polarizing beam splitting prism. The second light is reflected to the second rear group lens; or the mirror is at the first optical path, the polarizing beam splitting prism reflects the second light to the second rear group lens, and transmits the first light to the mirror, the mirror will The first light is reflected to the first rear group lens.

Preferably, the 3D projection lens further includes a timing polarization device disposed behind the first rear group lens and the second rear group lens, and the timing polarization device is configured to combine the first light sum from the first rear group lens and the second rear group lens The second light is converted into a linearly polarized light having the same polarization state and emitted to the screen; the time-series polarized light is a light whose polarization state changes with time, including linearly polarized light of left-handed circularly polarized light and right-handed circularly polarized light, and left-handed elliptically polarized light. And the time-polarized light of the right-handed elliptically polarized light or the linearly polarized light of two linearly polarized lights whose polarization directions are perpendicular to each other.

Preferably, the beam splitting unit comprises a polarization beam splitting prism disposed at an aperture stop position of the 3D projection lens for splitting the incident image light into a first light having a first polarization state and a second light polarization state The two lights emit the first light of the first polarization state and the second light of the second polarization state to the screen through the first rear group lens and the second rear group lens, respectively.

Preferably, the beam splitting unit comprises a wavelength splitting device, and the wavelength splitting device is disposed at an aperture stop position of the 3D projection lens for splitting the incident image light into first light and second light having different spectral ranges, and will have different The first light and the second light of the spectral range are emitted to the screen via the first rear group lens and the second rear group lens, respectively.

According to a second aspect of the present invention, there is provided a 3D projection apparatus comprising a light source, a light modulation unit, and the above-described 3D projection lens; a light beam of the light source is incident on the light modulation unit; and the light modulation unit modulates the light beam from the light source to form a Imaging the image light and emitting the image light to the 3D projection lens; the 3D projection lens receives the image light from the light modulation unit and splits the light into at least a plurality of light including the first light and the second light, and projects the light onto the screen to modulate the light The image produced by the surface of the unit is imaged to the screen.

Preferably, the cross-sectional area of the image light emitted by the single light modulation unit is less than or equal to the aperture stop cross-sectional area.

Beneficial effect

The 3D projection lens and the 3D projection device of the present invention are defined by an aperture stop, and the front group is made by dividing the lens into a front group lens unit and a rear group lens unit including a first rear group lens and a second rear group lens. The lens unit corresponds to two rear group lenses, and the portion for splitting in the beam splitting unit is disposed at the pupil position of the projection lens. On the one hand, the 3D system is realized inside the projection lens, which reduces the volume of the 3D system, minimizes the volume of the light splitting unit, reduces the cost, and avoids the distance between the light modulator and the projection lens is too long, and does not need to set an additional medium. Forming the intermediate image along the mirror group reduces the design difficulty of the lens and solves the practical problem. Moreover, the spectroscopic unit is disposed at the aperture stop position, and the light incident on the spectroscopic unit has a smaller emission angle than the spectroscopic unit is disposed behind the lens, which is advantageous for improving the light utilization efficiency of the spectroscopic unit, thereby improving the 3D system. The light utilization efficiency enhances the 3D display brightness.

DRAWINGS

1 is a schematic structural view of a projection lens of the prior art;

2 is a schematic diagram of a 3D projection device of Embodiment 1;

3 is a schematic view of a 3D projection lens of Embodiment 1;

Figure 4 is a side view of the PBS prism and the aperture stop of the first embodiment;

Figure 5 is a front view of the PBS prism and the aperture stop of the first embodiment;

6 is a schematic diagram of optical parameters of a beam splitting unit of Embodiment 1;

7 is a schematic diagram of a 3D projection device of Embodiment 2.

BEST MODE FOR CARRYING OUT THE INVENTION

The details of the embodiments are described in detail below with reference to the accompanying drawings.

Embodiment 1:

As shown in FIG. 2, the 3D projection apparatus of the present embodiment includes a light source 301, a color separation and color combining unit, a light modulation unit, and a 3D projection lens 308.

The light source 301 is used to generate illumination light required for projection, and may be a combination of a bulb, a semiconductor solid-state light-emitting device, a semiconductor solid-state light-emitting device, and a fluorescent material.

The color separation unit includes a light concentrating member 302, a relay lens 303, a mirror 304, and a TIR (total internal Reflection, total internal reflection) prism 305, beam splitting prism group, the prism group of the present embodiment specifically uses Philips prism 306; in other embodiments of the present invention, those skilled in the art can rationally design the optical path structure, and can also be arranged without The optical member 302, the relay lens 303, the mirror 304, the TIR prism 305, and the like.

The light modulating unit may include one or more light modulators, and the light modulating unit of the present embodiment specifically includes a blue light modulator 307a, a red light modulator 307b, and a green light modulator 307c. The light modulator in this embodiment is specifically DMD (Digital Micromirro Device, in other embodiments of the present invention, the optical modulator may also be other optical modulators such as LCD, LCOS, and the like.

During the projection process, the light source 301 emits a light beam to the light homogenizing component 302. The light homogenizing component 302 performs a homogenizing process on the light beam and exits to the relay lens 303. The relay lens 303 converges the light beam to the mirror 304, and the light beam passes through the mirror 304. It is reflected to the TIR prism 305 and further reflected by the TIR prism 305 to the Philips prism 306.

The Philips prism 306 transmits, reflects, and refracts the light beam, thereby splitting the light beam into a plurality of beam splitting beams. In this embodiment, the beam is split by the Philips prism 306 to form a blue light splitting beam that is emitted to the blue light modulator 307a and the red light splitting beam. The red light modulator 307b is emitted, and the green light sub-beam is emitted to the green light modulator 307c.

The blue light modulator 307a, the red light modulator 307b, and the green light modulator 307c respectively modulate the blue light splitting beam, the red light component beam, and the green light component beam according to the control signal, and respectively form blue image light on the respective light modulator surfaces. , red image light and green image light, and each reflects the modulated partial beam back to the Philips prism 306, and the Philips prism 306 performs the reflection, transmission, etc. of the reflected partial beams to thereby modulate the modulated blue light beam. The red light sub-beam and the green light sub-beam converge and exit to the 3D projection lens 308.

In other embodiments of the present invention, it is also possible to design each light modulator to modulate the received partial beam and transmit it, and the transmitted partial beam is concentrated and emitted to the 3D projection lens.

In the projection apparatus of the present invention, the function of the projection lens is to project image light formed on the surface of the light modulator onto the screen in an imagewise manner, that is, to image the surface of the light modulator onto the screen.

As shown in FIG. 3, the 3D projection lens 308 of the present embodiment includes a front group lens unit 402, a beam splitting unit, a rear group lens unit, and a liquid crystal device 409. The light splitting unit includes a PBS prism 403 and a mirror 405, and a rear group lens unit. A first rear group lens 404 and a second rear group lens 406 are included, The PBS prism 403 is disposed at the aperture stop position of the 3D projection lens 308, and the combination of the PBS prism 403 or the PBS prism 403 and the mirror 405 of the present embodiment constitutes a 3D system in the 3D projection lens. The liquid crystal device 409 (for example, a liquid crystal display) is the sequential polarization device of the present embodiment. The time-series polarizing device can be a single block or a combination of two pieces. Of course, those skilled in the art will appreciate that it is not necessary to provide a timing polarization device.

In this embodiment, the front group lens unit 402 and the first rear group lens 404, the front group lens unit 402, and the second rear group lens 406 respectively form two independent first lenses and second lenses, respectively, respectively. The light exit surface of the modulator is imaged onto the screen. Further, the aperture positions of the first lens and the second lens coincide.

The aperture stop referred to in this embodiment may be a lens edge/frame, or may be a separate optical component, or may be a specific location in the optical path rather than a physical object. The aperture stop is considered from the overall design of the 3D projection lens. Its function is to control the illumination aperture angle of the object itself. Therefore, a specific position of the optical path can be reasonably selected as the aperture stop, and the aperture can be set independently at the position. The aperture element or lens edge. Those skilled in the art can determine the position and size of the aperture stop by analyzing the design of the projection lens structure. When the aperture stop is a separate optical component, it can adopt the arrangement of the optical path diaphragm 407 in FIG. 4; when the aperture stop is the lens edge/frame, the PBS prism 403 should be close enough to the edge, also conforming to The meaning of the "PBS prism 403 is set at the aperture stop position of the 3D projection lens" is referred to in the present invention; when the aperture stop is a non-physical position, for ease of understanding, the aperture stop 407 can be regarded as FIG. An imaginary structure in which the angle of illumination aperture is limited when the beam passes through this position. The PBS prism 403 is arranged such that the beam cross-sectional area of the image light at the PBS prism 403 is less than or equal to the aperture stop cross-sectional area.

For clarity of description, the blue modulation unit 307a, the red light modulator 307b, and the green light modulator 307c in the projection apparatus are denoted by the light modulation unit 401 in FIG.

During projection, the image light emitted by the light beam through the light modulation unit 401 is incident on the front group lens unit 402, and the front group lens unit 402 converges the image light onto the PBS prism 403. In the embodiment of the present invention, there is no relay lens between the light modulation unit 401 and the front group lens unit 402. It is known to those skilled in the art that the relay lens is independent of the projection lens, and the light modulator generates an intermediate image through the relay lens. In the embodiment of the present invention, the surface of the light modulation unit is imaged into the screen through the projection lens, and no intermediate image is generated. This shortens the distance between the light modulator and the projection lens, and eliminates the need to provide an additional relay lens group to form an intermediate image, which reduces the design difficulty of the lens.

As shown in the comparison file of FIG. 1, the technical solution utilizes a relay lens group to respectively image the light-emitting surface of the light modulator to the vicinity of the entrances of the two lenses, and then respectively image the two intermediate images onto the screen by using two lenses. . The technical solution increases the distance of the light modulator to the lens entrance by placing the PBS in front of the lens, and has to set a relay lens group 31 to image the light modulator to the lens entrance, replacing the "image of the light modulator". The light modulator is "in order to improve the quality of the lens image. To this end, the technical solution not only sacrifices the overall volume, but also sacrifices cost, and also causes additional light transmittance loss and light collection loss due to the addition of the relay lens group 31.

The technical solution of the embodiment directly places the light modulator in front of the lens entrance, and directly images the "light modulator" through the lens to the screen, thereby avoiding the light transmittance loss of the intermediate process while ensuring the image quality. And light collection losses, no additional costs due to the addition of PBS. Moreover, the front group lens unit 402 is reused as a common portion of the two lenses, and the lens cost is reduced relative to other two-lens technical solutions.

The PBS prism 403 receives the image light as an example. The PBS prism 403 splits the red light to obtain the first light and the second light. At this time, the first light is the P light having the first polarization state, and the second light is S light having a second polarization state. The first light path is the first light path, and the second light path is the second light path. The first rear group lens 404 and the second rear group lens 406 are respectively on the first light path and the second light path. The optical axes of the first rear group lens 404 and the second rear group lens 406 are not parallel, and the second rear group lens 406 requires a certain offset (optical axis offset), and the offset is adjustable to accommodate different projection distances and Make sure that the two beams of light coincide on the screen.

The PBS prism transmits P light along the first optical path to the first rear group lens 404, and reflects the S light along the second optical path to the mirror 405.

The embodiment further includes a polarization conversion component (not shown) behind the mirror 405 on the second optical path, and the S light reflected by the mirror 405 is converted into P light by the polarization conversion component and is output to the second rear group. Lens 406. The purpose of providing the polarization conversion component is to have the first light incident to the first rear group lens 404 and the second light incident to the second rear lens 406 have the same polarization state, and thus in other embodiments, the polarization conversion component It can also be on the first optical path for converting the first light into S light.

The first rear group lens 404 emits the first light (P light) and the second rear group lens 406 to the liquid crystal device 409, and the first light and the second light pass through the liquid crystal device 409 together. Converted into time-separated polarized light, which is a left-handed circularly polarized light and a right-handed circularly polarized light whose polarization state changes with time (ie, the first light and the second light are converted into left-handed circularly polarized light together at a certain time period, In the second time period, it is converted into right-handed circularly polarized light, which is cycled in time series, so that it is projected onto the screen and superimposed to realize the 3D effect. In other embodiments of the present invention, it is also possible that the first light and the second light become a time-series left-handed elliptically polarized light and right-handed elliptically polarized light after passing through the liquid crystal device 409, or two linear polarizations whose polarization directions are perpendicular to each other. Light can also achieve 3D effects.

As shown in FIGS. 4 and 5, the PBS prism 403 is disposed at the aperture stop 407 of the 3D projection lens 308, the aperture height of the aperture stop 407 is D, and the light height from the spatial light modulator is h. And D ≥ h. With the PBS prism 403 confined within the aperture stop 407, the PBS prism 403 can be sized as the aperture stop 407, such that the volume of the PBS prism 403 is minimized. Those skilled in the art will appreciate that aperture stop 407 can be circular, square or any other suitable shape, and is not limited by Figures 4 and 5.

The PBS prism 403 realizes reflection and transmission through coating, and its effect is related to the divergence angle of the incident light. The larger the image light divergence angle is, the worse the effect of the PBS prism is. The smaller the image light emission angle is, the better the effect of the PBS prism is. . It should be noted that the light divergence angle and the light incident angle are different concepts. Those skilled in the art discuss the light incident angle to design the optical path. The first consideration is the main optical axis of the light, that is, as shown in the figure, the light incident angle is Designed by considering the incident angle of the main optical axis to be about 45° incident on the spectroscopic film, and the divergence angle is a description of the outward divergence of the beam centered on the main optical axis, that is, the beam is reflected by the main optical axis and the spectroscopic film. At 45° incidence, there is light incident at 40° or 50° in the beam (herein, by way of example only, not limited thereto). The design of the coating is based on the direction of the main optical axis. The optical path of the other angles in the film is different from the main optical axis. Therefore, the characteristics of the spectral film are not well matched to the light of other angles. The greater the difference in angle That is, the larger the divergence angle, the more obvious this effect is.

As shown in FIG. 6, the area of the image light emitted from the light modulating unit 401 is S1, and the half angle of the light emission is α. After passing through the front group lens 402, it converges at the pupil 407, and the area of the pupil is S2, where The light emission half angle is β, and light is imaged onto the screen 408 through the rear group lens 405, and the beam tilt angle from the rear group lens 405 is θ.

Roughly estimating, in the case where the image light is assumed to be a uniform light distribution, any point on the cross section of the light beam at the position of the aperture stop includes image light emitted from an arbitrary pixel point on the light modulation unit 401, and is conserved according to the optical spread amount. S1sin2α=S2sin2β, where S1, α, S2, and β are variables; generally, α is 8°~18° according to the design of lens F#, and if S1 and S2 are equal, α=β, β is also 8°~ 18°, or S2 is larger, so β will be smaller. In an embodiment of the present invention, the cross-sectional area of the image light emitted by the single light modulating unit is less than or equal to the cross-sectional area of the aperture stop such that the divergence angle of the light beam at the position of the light splitting unit is smaller than the divergence angle of the light modulating unit, thereby improving The efficiency of the splitting unit.

θ is calculated from the projection ratio of the lens TR, TR = 1/2 tan θ; the projection ratio of the cinema projector lens is generally about 1.0, θ is about 26 °, and for the ultra-short-throw projector, the projection ratio TR is only 0.24, θ More than 60°. In the technical solution of the present invention, β is smaller than θ, and a PBS prism is placed at the stop 407, and the PBS prism is more effective and more efficient. In the prior art, a PBS prism is disposed behind the lens, since θ is determined to be unchanged once the beam is emitted from the lens. If the above typical value θ exceeds 26° or even 70°, the divergence of the light beam incident on the PBS prism will be caused. The angle is very large, the PBS prism's splitting effect is greatly reduced, a large amount of light can not be used, lost in the process of projecting the lens to the screen. The light splitting unit of the present invention is disposed at the aperture stop position, and the divergence angle of the incident light is small, which is beneficial to improving the light utilization efficiency of the light splitting unit, thereby improving the light utilization efficiency of the 3D system and enhancing the 3D display brightness.

In another embodiment of the present invention, the PBS prism may transmit the first light, reflect the second light, and provide a mirror on the first optical path. The PBS prism transmits the first light to the mirror, the mirror reflects the first light to the first rear group lens; the PBS prism transmits the second light to the second rear group lens; the first rear group lens will be the first light, the first The second rear group lens emits the second light to the screen, and after being superimposed, presents a 3D effect.

In another embodiment of the present invention, the beam splitting unit is a polarization beam splitting prism, and the polarization beam splitting prism is disposed at an aperture stop position of the 3D projection lens for dividing the incident image light into the first light having the first polarization state (P The light and the second light (S light) having the second polarization state, and the first light and the second light are emitted to the screen, and the user can experience the 3D effect by wearing appropriate polarizing glasses.

In the first embodiment of the present invention, the light modulation unit includes three light modulators for respectively modulating three colors. In other embodiments of the invention, the light modulating unit may also include other numbers of light modulators. For example, in one embodiment, the light modulating unit includes at least one light modulator that emits time-series image light by modulating color light (red, green, blue, red, green, blue, and yellow) that is incident at time. In another embodiment, the light modulating unit comprises at least two light modulators, one of which modulates monochromatic light (such as any of red, green and blue), and the other of which modulates the timed incident colored light (such as the remaining two of red, green and blue), the monochromatic image light and the time series image light respectively emitted by the two light modulators are combined to form a color image.

Embodiment 2:

As shown in Figure 7, The 3D projection apparatus of this embodiment includes a light source 601, a uniform lens 602, a relay lens 603, a mirror 604, a TIR prism 605, a first spatial light modulator 606a, a second spatial light modulator 606b, a projection lens 607, and a screen. 608. The projection lens 607 of this embodiment adopts the basic structure of the projection lens of the first embodiment, and also includes a PBS prism and a mirror. The TIR prism splits the beam into two beams, and the two spatial light modulators respectively modulate the partial beam to form a left eye image light and a right eye image light, and the left eye image light (P light) is transmitted through the PBS prism, and then passes through the After the group lens is emitted, it becomes left-handed circularly polarized light through the 1/4 wave plate, and becomes the left-eye image light on the screen; the right-eye image light (S-light) is reflected by the PBS prism, and then exits through the second rear group lens. The 1/4 wave plate becomes right-handed circularly polarized light, and becomes right-eye image light on the screen, and the left-eye image light and the right-eye image light are superimposed on the screen 608, and the user wears appropriate polarizing glasses, that is, Can experience 3D effects.

Embodiment 3:

The 3D projection device of this embodiment adopts the basic structure of the first embodiment, and is different from the first embodiment in that the 3D projection lens of the embodiment replaces the PBS prism with a wavelength splitting device, and the wavelength splitting device is disposed at the aperture stop of the 3D projection lens. a position for dividing the incident image light into first light and second light having different spectral ranges. For example, the image light is a wide-spectrum RGB light, and the first light and the second light are respectively RGB light of different spectra, and the first light and the second light are respectively emitted through the first rear group lens and the second rear group lens to The screen is superimposed, and the user can experience the 3D effect by wearing appropriate polarizer glasses. The relationship between the spectral efficiency of the wavelength splitting device and the divergence angle of the incident beam also follows the relationship between the spectral efficiency of the polarization splitting device and the divergence angle of the incident beam.

The 3D projection lens and the 3D projection device of the present invention integrate a 3D system, that is, a light splitting unit (such as a PBS prism or a combination of a PBS prism 403 and a mirror 405) into the inside of the projection lens, in the front group lens unit and the rear group lens unit. By setting the 3D system, the 3D system is realized inside the projection lens on the one hand, which saves the volume of the 3D system, and the light splitting unit is disposed at the pupil position of the projection lens, so that the volume of the light splitting unit is minimized. The distance between the light modulator and the projection lens is prevented from being too long, the design difficulty of the lens is reduced, and the practical problem is solved; on the other hand, since the angle of the light beam at the pupil position is small, the light splitting unit has higher efficiency and improves. The light extraction efficiency of the 3D system enhances the 3D brightness, which is of great significance for the further development of the 3D projection device.

The above is a further detailed description of the specific embodiments, and the specific implementations that cannot be determined are limited to these descriptions. For those of ordinary skill in the art, a number of simple derivations or substitutions can be made without departing from the concept.

Claims (10)

1. A 3D projection lens, comprising: a front group lens unit, a beam splitting unit, and a rear group lens unit, wherein the rear group lens unit comprises at least a first rear group lens and a second rear group lens; The front group lens unit receives image light and converges the image light to the beam splitting unit; a portion of the spectroscopic unit for splitting light is disposed at an aperture stop position of the 3D projection lens; the spectroscopic unit receives image light from the front group lens unit, and splits the image light to obtain a plurality of beams, The plurality of beams of light include at least first light and second light of different propagation directions; the beam splitting unit directs the first light along the first optical path to the first rear group lens, and the second light along the second light The light path is guided out to the second rear group lens; The first rear group lens and the second rear group lens are respectively located on the first optical path and the second optical path; The first rear group lens receives the first light and exits, and the second rear group lens receives the second light and exits. 2. The lens of claim 1 wherein: The light splitting unit is arranged such that a beam cross-sectional area of the image light at the beam splitting unit is less than or equal to the aperture stop cross-sectional area. 3. The lens of claim 1 wherein: The second rear group lens has a certain optical axis offset with respect to the first rear group lens, so that the first light emitted by the first rear group lens and the second light emitted by the second rear group lens Light coincides on the screen. The lens according to any one of claims 1 to 3, wherein The beam splitting unit includes a polarization beam splitting prism disposed at an aperture stop position of the 3D projection lens for dividing the incident image light into a first light having a first polarization state and a second polarization state Second light The 3D projection lens further includes a polarization conversion component, the polarization conversion component being on the first optical path or the second optical path for converting the first light into the second polarization state or converting the second light into the first light a polarization state such that the first light incident to the first rear group lens and the second light incident to the second rear group lens have the same polarization state. The lens according to claim 4, wherein the beam splitting unit further comprises a mirror; The mirror is at a second optical path, the polarizing beam splitting prism transmitting first light to the first rear group lens, reflecting second light to the mirror, the mirror receiving the polarizing beam splitting prism Second light and reflecting it to the second rear lens; or The mirror is at a first optical path, the polarizing beam splitting prism reflecting the second light to the second rear lens, transmitting the first light to the mirror, the mirror reflecting the first light to the The first rear group lens. 6. The lens of claim 4, wherein The 3D projection lens further includes a timing polarization device disposed after the first rear group lens and the second rear group lens, the timing polarization device for using the first rear group lens and the first The first light and the second light of the two rear group lenses are converted into time-polarized light of the same polarization state and emitted to the screen; The time-series polarized light is light whose polarization state changes with time, including time-polarized light of left-handed circularly polarized light and right-handed circularly polarized light, time-polarized light of left-handed elliptically polarized light and right-handed elliptically polarized light, or polarization directions perpendicular to each other. Time-polarized light of two linearly polarized lights. 7. A lens according to any one of claims 1 to 3, wherein The beam splitting unit includes a polarization beam splitting prism disposed at an aperture stop position of the 3D projection lens for dividing the incident image light into a first light having a first polarization state and a second polarization state The second light emits the first light of the first polarization state and the second light of the second polarization state to the screen through the first rear group lens and the second rear group lens, respectively. The lens according to any one of claims 1 to 3, wherein The light splitting unit includes a wavelength splitting device, and the wavelength splitting device is disposed at an aperture stop position of the 3D projection lens, and is configured to split incident image light into first light and second light having different spectral ranges, and have The first light and the second light of different spectral ranges are emitted to the screen through the first rear group lens and the second rear group lens, respectively. 9. A 3D projection device, comprising: a light source, a light modulation unit, the 3D projection lens according to any one of claims 1-8; a light beam of the light source is incident on the light modulation unit; The light modulating unit modulates a light beam from the light source to form image light for imaging, and emits the image light to the 3D projection lens; The 3D projection lens receives image light from the light modulation unit, and splits the image light into a plurality of beams including at least a first light and a second light, and then projects the image to a screen to cause an image generated on a surface of the light modulation unit Image to the screen. 10. The projection apparatus according to claim 9, wherein a sectional area of the image light emitted from the single light modulating unit is equal to or smaller than the aperture stop cross-sectional area.