CN106990667B

CN106990667B - Stereoscopic projection imaging device and system

Info

Publication number: CN106990667B
Application number: CN201710377121.1A
Authority: CN
Inventors: 时国庆; 高建辉
Original assignee: Qingdao Volfoni Rio Vision Technology Co ltd
Current assignee: Qingdao Volfoni Rio Vision Technology Co ltd
Priority date: 2017-05-25
Filing date: 2017-05-25
Publication date: 2022-08-09
Anticipated expiration: 2037-05-25
Also published as: CN106990667A

Abstract

The invention discloses a high-light-efficiency stereoscopic projection imaging device and a high-light-efficiency stereoscopic projection imaging system which can recover a light path, reduce the light energy loss and improve the projection imaging quality and are suitable for a low-projection-ratio cinema environment. The stereo projection imaging device provided by the invention can effectively reduce the optical path difference between the reflected light beam and the transmitted light beam, so that the whole structure is more optimized, and the volume of the whole device is greatly reduced.

Description

Stereoscopic projection imaging device and system

Technical Field

The invention relates to the technical field of stereoscopic projection, in particular to a stereoscopic projection imaging device and system.

Background

The stereoscopic projector sequentially converts and plays two images of different sequences in a frame sequence, the current mainstream is a left-eye image and a right-eye image, one sequence is seen by a left eye, the other sequence is seen by a right eye, and stereoscopic images are alternately presented. Viewers are usually wearing stereoscopic glasses through which each eye of the viewer can only see a sub-sequence of images prepared for him. There are currently stereoscopic imaging systems for passive stereoscopic eyewear. Different sequences of images from the projector are initially non-polarized state beams, and the non-polarized state beams are converted into polarized state beams by a polarization beam splitter configured in the stereoscopic imaging system.

However, most of the conventional stereoscopic projection imaging apparatuses have problems such as large optical energy loss, optical energy scattering, chromatic aberration, and the like, and the quality of projected images is poor.

Disclosure of Invention

In order to solve the above problems, the present invention provides a high light efficiency stereoscopic projection imaging apparatus and system which can perform optical path recovery, reduce optical energy loss, and improve projection imaging quality, and which are suitable for a low aspect ratio cinema environment.

In order to achieve the purpose, the invention provides the following technical scheme: a stereoscopic projection imaging apparatus comprising:

the polarization beam splitter is a polarization beam splitter prism combination or a polarization beam splitting plate and is used for splitting incident light into a transmission light beam and two reflection light beams, the polarization beam splitter is provided with two polarization reflection films, the two polarization reflection films are symmetrical along a system central line and form an angle of 90 degrees +/-15 degrees, and reflection emergent surfaces of the prisms are symmetrical along the system central line and form an angle of 90 degrees +/-15 degrees;

the reflecting elements are symmetrically distributed along the central line of incident light and used for reflecting two reflected light beams reflected by the polarization beam splitter to a screen, the reflecting elements adopt high-reflection polarized light elements, the high-reflection polarized light elements are composed of a protective layer, a reflecting layer, an absorbing layer and a glass substrate, the light path can be effectively protected from being influenced by stray light, redundant P polarized light of upper and lower light paths is absorbed, the reflecting efficiency is improved, and the light efficiency of the whole system is improved;

the reflection element adjusting structure is used for carrying out space position and surface shape transformation through mechanical regulation according to the requirement of light beam projection, and finishing the adjustment of the size and the position of a reflected light beam so as to realize the superposition of a light path;

and the light beam size adjusting component is used for adjusting the sizes of the transmission light beam and the two reflection light beams, enabling the three light paths to be overlapped on the screen, adjusting the scattering of the light beams and eliminating stray light in the light paths, and correcting the light paths by matching with other optical elements of the system, and the light beam size adjusting component is a single lens or a combination of a plurality of lenses.

The linear polarizer is used for filtering stray light in the reflected light path and correcting the adjustment of the light path;

the polarization modulators are used for modulating the three paths of light beams, the phase difference between the two polarization modulators is 1/2 lambda in the working state, and the light beams are separated by high-frequency switch switching of the two polarization modulators so as to correspond to different polarization filters of two lenses of the passive circular polarized glasses;

and the polarization state converter is used for changing the polarization state of the light beams to enable the three light beams to have the same optical polarization state, and the polarization state converter has a wavelength bandwidth adjusting function.

Furthermore, two sides of the polarization beam splitter are respectively provided with an AR anti-reflection film, and the AR anti-reflection films are plated on the reflecting exit surface of the prism to reduce the reflection of the light path.

Further, the projected reflective area of the reflective element is designed as an area with a certain radius of curvature.

Furthermore, the polarization converter comprises at least three layers of optical films, has an optical compensation function, and improves the problems of chromatic aberration and chromatic dispersion.

Further, the lens combination is arranged in front of the polarization beam splitter and/or in front of the upper optical path polarizer and/or in front of the lower optical path linear polarizer and/or in front of the intermediate optical path polarization modulator, and the number of the lenses or the lens combination and the relative positions of the plano-concave lens and the plano-convex lens of the lens combination are adjusted according to the requirement of the cinema projection ratio.

A stereoscopic projection imaging system comprises a stereoscopic projector, a metal screen or a curtain with stereoscopic imaging requirements and the stereoscopic projection imaging device, wherein the stereoscopic projector sequentially converts and plays images of two different sequences in a frame sequence, and the stereoscopic projection imaging device receives frequency signals of the stereoscopic projector switching and playing the images of the two different sequences to control a first polarization modulator and a second polarization modulator, so that the images of the two different sequences are separated into light beams in two different optical polarization states to correspond to different polarization filters of two lenses of passive circular polarized glasses.

Compared with the prior art, the invention has the beneficial effects that:

1. the size of the light beam can be adjusted by the adjusting structure of the reflecting element, and the problem of poor image quality caused by incomplete superposition of the light beam on a screen is solved.

2. The light beam size adjusting component can adjust the sizes of the transmitted light beam and the two reflected light beams according to different placement positions as required, so that the three light paths are overlapped on the screen, and the scattering of the light beams is adjusted; meanwhile, the scattering of the light beam is adjusted, stray light in the light path is eliminated, and the light path is corrected by matching with other optical elements of the system; especially in the cinema with low projection ratio, the beam size adjusting component is arranged on the front light path, which is beneficial to reducing the size of the main optical elements of the system.

3. For different projection distances of the cinema, the divergence angle of projection light, the distance from the transmission light path to the screen, the distance from the reflection light path to the screen and the distance from the transmission light path to the screen are different, so that the projection size on the screen is different, the system designs a certain curvature radius for the projection area of the reflection element so as to match the projection range of 4-30 meters and achieve the superposition of the three light paths through the mechanical regulation and control of the reflection element, such as up-down, left-right rotation, surface shape change and the like.

4. The polarization converter has the function of optical compensation, can solve the problems of large light beam projection angle, poor image quality caused by image scattering and color difference of a projected image, and provides a solution for a low-projection-ratio photo hall.

Drawings

Fig. 1 is a schematic view of a stereoscopic projection imaging device provided by the invention.

Fig. 2 is another form of a stereoscopic projection imaging apparatus provided by the present invention.

Fig. 3 is another form of a stereoscopic projection imaging apparatus provided by the present invention.

Fig. 4 is a schematic diagram of a polarization beam splitter provided by the present invention.

Fig. 5 is another form of a polarization beam splitter provided by the present invention.

FIG. 6 is another version of a polarization splitter provided by the present invention.

Fig. 7 is an optical path analysis diagram of the high-reflection polarization element provided by the invention.

FIG. 8 is a schematic view of the optical path of the adjusting structure of the reflective element provided in the present invention

Fig. 9 is a schematic diagram of an optical path of the highly reflective polarizing element according to the present invention.

Fig. 10 is an optical path schematic diagram and an optical structure diagram of the high-reflection polarization element provided by the present invention.

Fig. 11 is a schematic view showing the coincidence of the optical paths of the reflecting element provided by the present invention.

Fig. 12 is a schematic diagram of optical compensation of the polarization converter provided by the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, the present invention provides a stereoscopic projection imaging apparatus, which includes a light beam size adjusting assembly, i.e.

lens assemblies

102 and 103, an incident light beam 137 enters the lens assembly, and the incident light beam is adjusted by the lens assembly to be smaller in the incident range, and particularly, the structure can be applied to a lower throw ratio in a solution of a low throw ratio photo hall, and then the light beam passes through a polarization beam splitter 104 and is divided into a transmitted incident light beam 109 and two reflected

light beams

108 and 133, after the separation, the transmitted light beam 109 is P-state polarized light, and the two

reflected light beams

108 and 133 are S-state polarized light, and the difference between the two is 1/2 λ;

the projected range of the transmitted light beam 109 is enlarged by the plano-convex lens 132 and the plano-concave lens 131, after which the projected light beam enters the

polarization modulators

117 and 118, the first polarization modulator 117 is in the hold state, the polarization state light passes directly through the first polarization modulator, while the second polarization modulator 118 is in the working state, the polarization state of the light will be rotated 1/4 λ, or the first polarization modulator 117 is in the working state, the polarization state of the second optical polarization state light will be changed to-1/4 λ, while the second polarization modulator 118 is in the hold state, the light will pass directly through the second polarization modulator 118, both polarization modulators function as polarization state converters, and both polarization modulators differ by 1/2 λ in operation; the high-frequency switches of the two polarization modulators are switched to separate the light beams in two optical polarization states so as to correspond to different polarization filters of two lenses of the passive circular polarized glasses;

the

reflected light beams

108 and 133 are respectively incident to the

reflective elements

107 and 134, the

reflective elements

107 and 134 can be mechanically controlled by a reflective element adjusting structure, the size of the light beams and the movement of the upper direction, the lower direction, the left direction and the right direction are adjusted, so that the light paths are overlapped, the reflected light beam 108 passes through the

lens combinations

110 and 111 after being reflected by the reflective element, the distance between the plano-concave lens and the plano-convex lens is adjusted according to requirements, the projection range of the light beams is adjusted, namely the size of the light beams is adjusted, the linear polarizer 112 is arranged after the lens combinations, stray light mixed in S-state polarized light in the reflected light beam 108 is filtered and eliminated, linearly polarized light after passing through the linear polarizer 112 enters the

subsequent polarization modulators

113 and 114, so that the light beams in two optical polarization states are separated, the light beams corresponding to different polarization filters of two lenses of the passive circularly polarized glasses enter the

polarization converters

115 and 116, the

polarization state converters

115 and 116 each function as an 1/4 wave plate, cumulatively as a 1/2 wave plate; the polarization state changing device is used for changing the optical polarization state of the light beams so that the three light beams have the same optical polarization state.

The stereo projection imaging device of the form is added with a plurality of lens combinations, the structure can be suitable for lower projection ratio, the projection ratio suitable for most of the current stereo projection imaging devices is 1.0-1.2 at the lowest, and the stereo projection imaging device of the structure can be suitable for a studio with the projection ratio of 0.5-0.8.

Fig. 2 is another form of the stereoscopic projection imaging apparatus provided by the present invention, the stereoscopic projection imaging apparatus with this structure eliminates the lens combination, and realizes the coincidence of three optical paths by means of the

reflective elements

107 and 134, and the

reflective elements

107 and 134 are designed with curvature radius in the reflective area to meet the requirements of different projection distances.

Fig. 3 shows another form of a stereoscopic projection imaging apparatus according to the present invention. The stereo projection imaging device in the form cancels the polarization converters of the upper and lower light paths, adds the

polarization converters

301 and 302 of the middle light path, and after the polarization converters are changed, the upper, middle and lower light paths can also realize the consistency of the polarization states of the upper, middle and lower light paths; meanwhile, the reflecting element 107 adopts a polarization high-reflectivity element, so that the influence of stray light on the upper and lower light paths is reduced.

Fig. 4 is a schematic structural diagram of a polarization beam splitter according to the present invention, the polarization beam splitter is a polarization beam splitter prism combination, and includes four

prisms

402, 403, 408, and 411, the four portions may be made of materials with the same or different refractive indexes, and the material normally used is H-K9L, and the refractive index nd is 1.51680 ± 0.0005. The range of alpha is 50-90 degrees, the range of beta is 90-180 degrees, the included angles of 403 and 411 are consistent with alpha and are symmetrical along the central line of the system, and the elimination of stray light and reflected light of the whole light path is adjusted by adjusting the three included angles; the reflecting and emitting surface of the prism is plated with an AR anti-reflection film for reducing the generation of reflected light and increasing the transmittance; the incident light can be prevented from directly entering the polarization beam splitter to cause dispersion problem in the structure.

Fig. 5 is another schematic structural diagram of a polarization beam splitter provided by the present invention, the polarization beam splitter of the structure is composed of six

prisms

502, 503, 504, 509, 513, 514, 503, 504 and 513, 514 are symmetrical along the center of the system, and the material with the same refractive index and dispersion ratio or different refractive index dispersion ratio as other parts is used to modify the optical path characteristics by using the optical path refraction; and is suitable for adjusting the light path in cooperation with the lens combination.

Fig. 6 is a schematic diagram of another structure of the polarization beam splitter provided by the present invention, the polarization beam splitter of the structure is composed of four

prisms

602, 603, 607, 610, and the structure of the structure can avoid the dispersion problem caused by the direct incidence of the incident light to the polarization beam splitter; the range of alpha is 50-90 degrees, the included angles of 603 and 610 are consistent with alpha and symmetrical along the central line of the system, and the elimination of stray light and reflected light of the whole light path is adjusted by adjusting the three included angles; and an AR anti-reflection film coated on the reflection and emission surface of the prism to reduce the generation of reflected light and increase the transmittance.

The polarization beam splitter provided by the invention can also be a combination of a plurality of polarization beam splitting plates.

Fig. 7 is an optical path analysis diagram of a high-reflection polarization element provided by the present invention, in an initial state, an initial light beam Tp is 100%/Ts is 100%, after passing through a polarization reflection film, a transmitted light beam Tp1 is 96%/Ts1 is 0.1%, a reflected light beam Rp1 is 4%/Rs1 is 99.9%, a reflected light beam passes through the high-reflection polarization element 702, the element efficiency is Rp3 is 5%/Rs3 is 99%, and the resulting Rp2 is Rp1, Rp3 is 4%/Rs 5%/Rs 2 is 99.9%/Rs 1 is 99.9%/Rs 3 is 99.9%/98.9%; by means of the design, higher luminous efficiency of the system can be achieved. The high-reflection polarizing element is used as a reflection element, the light efficiency can be increased by 6% compared with that of a common reflection element, and the interference of P-state polarized light of upper and lower light paths on the light path can be effectively improved.

Fig. 8 is a schematic view of a light path of the adjustment structure of the reflective element according to the present invention. A reflecting element 803 for reflecting the two reflected light beams reflected by the polarization beam splitter to the screen; the reflecting element can rotate, move, push and pull and deform the spatial position according to the requirement of light beam projection, and the size and the position of a reflected light beam are adjusted to realize the superposition of light paths. After the incident light beam 801 is reflected by the reflecting element 803, a light beam 805 is obtained; after the reflective element 803 is shrunk and deformed, 802 is obtained, and after the incident light beam 801 passes through the reflective element 802, a light beam 804 is obtained; obviously, the projection direction of the reflected light beam can be adjusted through the adjustment; after such adjustment, the upper, middle, and lower optical paths can be made to coincide. The structure can be matched with a lens combination, so that the adjustment range of the system is enlarged, and the adjustment of the system is more careful and accurate.

Fig. 9 is a schematic diagram of an optical path of the high-reflection polarization element according to the present invention, in which when a light ray is incident at a brewster angle, only S-polarized light is present in the reflected light ray, and no P-polarized light is present in the reflected light ray, and the P-polarized light is completely transmitted through the reflected light ray. The brewster angle is related to the refractive indices of the two materials at the incident interface, such as 56.5 ° for incident K9 glass from air. When designing the high-reflection polarizing element, the multilayer film system is reasonably designed, the Brewster effect is ensured to be met in a wider wave band range as much as possible, S polarized light is reflected as high as possible, and P polarized light is transmitted as high as possible. As shown in fig. 9, in the high efficiency state, the initial light beam Tp is 100%/Ts is 100%, Rp is 0/Rs is 15.2% after reflection, Rp1 is 0%/Rs 1 is 84.8% 15.2% 84.8% after refraction and reflection, and the light beam projected after refraction and Tp is 100%/Ts is 84.8%, and the film system is constructed according to this design, so that almost P-polarized light is transmitted and S-polarized light is highly reflected.

Fig. 10 is an optical path schematic diagram and an optical structure diagram of a high-reflection polarizing element provided by the present invention, the high-reflection polarizing element is composed of a protective layer 1001, a reflective layer 1002, an absorbing layer 1003, and a glass substrate 1004; the optical path can be effectively protected from being influenced by stray light, and redundant P polarized light of the upper and lower optical paths can be absorbed; the reflecting layer is constructed by designing a film system according to the principle shown in fig. 9.

Fig. 11 is a schematic view showing the coincidence of the optical paths of the reflecting element provided by the present invention. The projection light has a divergence angle A, the paths from the transmission light path to the screen are different from the paths from the reflection light path to the screen, so that the projection sizes on the screen are different, namely a and b, and when the position of the screen is changed, the sizes of the a and the b are also changed. It is necessary to make a and b coincide by the curvature radius design and mechanical adjustment of the reflective element and adjustment of the lens combination.

FIG. 12 is a schematic diagram of an optical film capable of optical compensation according to the present invention, in which the optical characteristics of visible light with wavelengths of 400nm-700nm are different, especially when the viewing angle is relatively large, if optical compensation is not performed, the optical film has chromatic aberration and chromatic dispersion problems; when visible light passes through the 1/4 wave plate, the state of a line c is wanted to be pursued, but in fact, the state of a line a is obtained, and after proper optical compensation, the state of a line b can be obtained, so that the influence on the light of each wavelength of the visible light is well restrained; after passing through the next 1/4 slide optical compensation film, similar reverse phase compensation can be performed again, which will be closer to the c-line state, thereby solving and improving the problems of chromatic aberration and chromatic dispersion. The optical compensation film needs a plurality of optical films with different angles and different wavelengths to perform compensation synthesis, for example, three layers of optical films, namely 140nm (1/4 lambda) +108 DEG, 270nm (1/2 lambda) +32 DEG, and 270nm (1/2 lambda) +5.5 DEG are used for performing compensation synthesis, and after the three layers of optical films are synthesized, the optical compensation film has a function of 1/4 wave plates and has an optical compensation function.

It will be apparent to those skilled in the art that various changes and modifications may be made in the invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A stereoscopic projection imaging apparatus, comprising: the polarization beam splitter is a polarization beam splitter prism combination or a polarization beam splitting plate and is used for splitting incident light into a transmission incident beam and two reflection beams, the polarization beam splitter is provided with two polarization reflection films, the two polarization reflection films are symmetrical along a system central line and form an angle of 90 degrees +/-15 degrees, and reflection emergent surfaces of the prisms are symmetrical along the system central line and form an angle of 90 degrees +/-15 degrees; the included angle between the upper and lower beam splitting surfaces (605) and (608) of the polarization beam splitter and the horizontal direction is 15-15 degrees; the polarization splitting prism combination comprises four prisms (402), (403), (408) and (411), the four parts can adopt materials with the same or different refractive indexes, the material normally used is H-K9L, the refractive index is nd =1.51680 +/-0.0005, the range of alpha is 50 degrees to 90 degrees, the range of beta is 90 degrees to 180 degrees, the included angle of (403) and (411) is consistent with alpha and is symmetrical along the system center line, and the elimination of stray light and reflected light of the whole optical path is adjusted by adjusting the three included angles;

the reflection elements are symmetrically distributed along the central line of incident light and used for reflecting two reflected light beams reflected by the polarization beam splitter to a screen, the reflection elements adopt high-reflection polarized light elements, and the high-reflection polarized light elements are composed of a protection layer, a reflection layer, an absorption layer and a glass substrate; in the initial state, the initial light beam Tp =100%/Ts =100%, after passing through the polarizing reflective film, the transmitted incident light beam Tp1=96%/Ts1=0.1%, the reflected light beam Rp1=4%/Rs1=99.9%, the reflected light beam passing through the highly reflective polarizing element 702 with an efficiency Rp3=5%/Rs3=99%, the resulting Rp2= Rp1= Rp3=4% =5% =0.2%/Rs2= Rs1 × Rs3= 99.9%;

the reflection element adjusting structure is used for carrying out space position and surface shape transformation through mechanical regulation according to the requirement of light beam projection, and finishing the adjustment of the size and the position of a reflected light beam so as to realize the superposition of a light path; the reflecting element can rotate, move, push and pull and deform the space position according to the projection requirement of the light beam, the size and the position of the reflected light beam are adjusted, so that the light path is overlapped, and the light beam (805) is obtained after the incident light beam (801) is reflected by the reflecting element (803); the reflecting element (803) is contracted and deformed to obtain a reflecting element (802), and the incident light beam (801) passes through the reflecting element (802) to obtain a light beam (804);

the light beam size adjusting component is used for adjusting the sizes of the transmitted incident light beam and the two reflected light beams, enabling the three light paths to be overlapped on a screen, adjusting the scattering of the light beams and eliminating stray light in the light paths, and correcting the light paths by matching with other optical elements of the system, and the light beam size adjusting component is a single lens or a combination of a plurality of lenses; wherein, the light beam size adjusting component, namely lens combination (102) and (103), the incident beam (137) enters the lens combination, the incident range can be reduced through the adjustment of the lens combination, especially in the scheme of solving the low throw ratio video hall, the structure can be suitable for lower throw ratio, then, the light beam passes through the polarization beam splitter (104) and is divided into a transmission incident beam (109) and two reflected beams (108) and (133), after the separation, the transmission incident beam (109) is P state polarized light, the two reflected beams (108) and (133) are S state polarized light, the difference between the two is 1/2 lambda; the range of projection of the transmitted incident beam (109) is enlarged by a plano-convex lens (132) and a plano-concave lens (131), and thereafter, the projection beam enters the polarization modulators (117) and (118), the first polarization modulator (117) is in the hold state, and the polarization state light passes directly through the first polarization modulator, while the second polarization modulator (118) is in the active state, rotating the polarization state of the light 1/4 lambda, or the first polarization modulator (117) is in operation and changes the polarization of light of the second optical polarization state to-1/4 lambda, while the second polarization modulator (118) is in the hold state, the light passing directly through the second polarization modulator (118), both polarization modulators being in operation, the polarization state converter has the function of a polarization state converter, and the phase difference of the two polarization modulators is 1/2 lambda; the high-frequency switch switching of the two polarization modulators enables the light beams to realize the light beam separation of two optical polarization states so as to correspond to different polarization filters of two lenses of the passive circular polarized glasses; the reflected beams (108) and (133) are respectively incident to the reflecting elements (107) and (134), the reflecting elements (107) and (134) can be mechanically regulated and controlled through a reflecting element adjusting structure, the size of the beams and the movement of the upper direction, the lower direction, the left direction and the right direction are adjusted, so that the light paths are overlapped, the reflected beams (108) pass through the lens combinations (110) and (111), the distance between the plano-concave lens and the plano-convex lens is adjusted according to requirements, the projection range of the beams is adjusted, namely the size of the beams is adjusted, the linear polarizer (112) is arranged after the lens combinations, stray light mixed in S-state polarized light in the reflected beams (108) is filtered and eliminated, linearly polarized light after passing through the linear polarizer (112) enters the subsequent polarization modulators (113) and (114), so that the beams are separated into two optical polarization state light beams, and the polarization filters correspond to different polarization filters of two lenses of the passive circular glasses, the light beams passing through the polarization modulators (113) and (114) enter polarization state converters (115) and (116), wherein the polarization state converters (115) and (116) respectively have the function of 1/4 wave plates and are accumulated to have the function of 1/2 wave plates; the device is used for changing the optical polarization state of the light beams and enabling the three light beams to have the same optical polarization state;

the polarization state converter is used for changing the polarization state of the light beams to enable the three light beams to have the same optical polarization state, and the polarization state converter has a wavelength bandwidth adjusting function;

the projected reflective area of the reflective element is designed as an area with a radius of curvature;

the polarization converter at least comprises three layers of optical films, has an optical compensation function, and can improve the problems of chromatic aberration and chromatic dispersion;

the lens combination is arranged in front of the polarization beam splitter and/or in front of the upper light path polarizer and/or in front of the lower light path linear polarizer and/or in front of the middle light path polarization modulator, and the number of the lenses or the lens combination and the relative positions of the plano-concave lens and the plano-convex lens of the lens combination are adjusted according to the requirement of the cinema projection ratio;

the stereoscopic projection imaging device receives frequency signals of the stereoscopic projector for switching and playing the two different sequences of images to control the first polarization modulator and the second polarization modulator, so that the two different sequences of images are separated into two light beams with different optical polarization states to correspond to different polarization filters of two lenses of the passive circular polarized glasses;

and AR anti-reflection films are respectively arranged on two sides of the polarization beam splitter and plated on the reflecting exit surface of the prism, so that the light path reflection is reduced.