An ultrathin large-area uniform collimating backlight system for three-dimensional display

Abstract

This invention discloses an ultra-thin, large-area, uniform collimated backlight system for 3D displays, belonging to the field of free-form stereoscopic 3D displays. The collimated backlight includes a uniform panel light source, an orthogonal prism film composed of a first prism film and a second prism film, an aperture array layer, and an orthogonal cylindrical lens array composed of a first cylindrical lens array and a second cylindrical lens array. Both the orthogonal prism film and the orthogonal cylindrical lens array are double-layer structures, with the edges of the two prism films orthogonal to each other. The double-layer cylindrical lens array is arranged orthogonally to each other, and the cylindrical lens array is composed of cylindrical lens unit arrays. The upper and lower cylindrical lens arrays work together to achieve beam collimation and homogenization. The edges of the opposing prism film form a certain angle with the direction of the cylindrical lens arrangement, further homogenizing the light spot.

Description

Technical Field

[0001] This invention relates to the field of free-form stereoscopic display, and more particularly to an ultra-thin, large-area, uniform collimated backlight system for three-dimensional display. Background Technology

[0002] Display devices are crucial media for converting other forms of information into images, enabling living organisms to perceive visually. Because 3D displays can provide users with a more realistic perceptual experience, they have received increasing attention and research in recent years, and their development has been rapid.

[0003] Flat-panel glasses-free 3D display systems are devices that use the directional transmission of pixel images to create different viewpoints in different directions, allowing viewers to see a 3D effect. A typical flat-panel glasses-free 3D display system consists of a backlight system, a liquid crystal display (LCD), and beam-tuning lenses. The LCD itself does not emit light and requires a planar light source on its back for illumination; this is called a backlight. A highly collimated light source provides higher on-axis brightness, improving the viewing experience, and also prevents light from escaping into non-viewing areas, improving energy efficiency. 3D display devices place very high demands on the collimation of the backlight. Most 3D display devices rely on collimated planar light sources to accurately transmit specific images to different viewpoints; a highly collimated backlight helps with accurate imaging, reduces crosstalk, and improves viewing quality.

[0004] In existing glasses-free 3D display systems, backlights often require custom design to meet the requirements of subsequent 3D display devices, significantly increasing the processing requirements and costs of such systems. Furthermore, they generally suffer from large size, poor directivity, and low uniformity. These performance deficiencies in backlight systems result in low image quality, significant crosstalk between viewpoints, and a diminished user experience. Current backlight designs primarily employ dot-matrix structures, microprism structures, groove microstructures, and diffraction structures. Dot-matrix backlights can increase luminous uniformity and optimize visual perception through dot arrangement design, but it is difficult to control the collimation of the emitted light. Microprism backlights, similar to those using groove microstructures, break total internal reflection in the light guide plate through refraction and reflection, guiding the beam outward. This structure can control the total internal reflection light at a certain angle in a specific direction, but it exhibits high angular selectivity for the incident light, limiting collimation effectiveness; the divergence angle of the emitted beam is generally ±15° or higher. Diffraction structure designs have very high requirements for the angle and wavelength of the light source, severely restricting their practical application. If we can achieve high collimation and high uniformity based on the existing large divergence angle uniform backlights on the market, we can lower the threshold for naked-eye 3D display while maintaining the thinness of flat panel displays, reduce costs, and make great significance for the realization and promotion of flat panel naked-eye 3D display. Summary of the Invention

[0005] The purpose of this invention is to provide an ultra-thin, large-area, uniform collimated backlight system for three-dimensional displays, which can provide large-area, uniform, high-collimation white light illumination, and further provide a collimated backlight source for naked-eye three-dimensional display systems.

[0006] The present invention first provides an ultra-thin large-area uniform collimated backlight system for three-dimensional display. The system includes a uniform panel light source arranged along the optical path direction, an orthogonal prism film composed of two layers of first prism film and second prism film arranged in upper and lower positions, an aperture array layer, and an orthogonal cylindrical lens array composed of two layers of first cylindrical lens array and second cylindrical lens array arranged in upper and lower positions.

[0007] The orthogonal prism film is used to reduce the divergence angle of light emitted from the uniform panel light source. The edges of the first prism film and the second prism film are orthogonal to each other. The aperture array layer is an opaque film with light-transmitting holes evenly distributed in its row and column directions. The first cylindrical lens array and the second cylindrical lens array are arranged in orthogonal directions and are located above the aperture array layer. The periods of the first cylindrical lens array and the second cylindrical lens array are the same as the row and column periods of the light-transmitting holes. The orthogonal cylindrical lens array further reduces the divergence angle of light passing through the aperture array layer in both directions.

[0008] Furthermore, the shape of the light-transmitting aperture includes, but is not limited to, circles, squares, etc.

[0009] Furthermore, the uniform panel light source is a direct-lit large-area uniform backlight or a side-lit large-area uniform backlight.

[0010] Furthermore, the design methods for the first and second prism films are the same; the design parameters for the first and second prism films include the prism apex angle and the refractive index of the material. Let the prism apex angle be 2α, the incident light divergence angle be 2β, and the refractive index of the material be n. Using the law of refraction, the divergence angle of the outgoing light along the prism arrangement direction is calculated as follows: Therefore, the prism apex angle and material refractive index are selected based on the incident light divergence angle and the required outgoing light divergence angle.

[0011] Furthermore, the first cylindrical lens array is formed by arranging first cylindrical lenses along one direction; the second cylindrical lens array is formed by arranging second cylindrical lenses along another direction orthogonal to the aforementioned direction.

[0012] The second cylindrical lens array is located above the first cylindrical lens array. After passing through the first and second cylindrical lens arrays, the light beam will be homogenized and collimated, so that the energy of the light beam emitted through the aperture array layer is evenly distributed within a divergence angle of ±15°. The cross-sections of the first and second cylindrical lenses along their respective arrangement directions are high-order aspherical surfaces to achieve the effect of collimating the light rays.

[0013] Furthermore, let the widths of the first cylindrical lens and the second cylindrical lens be l1 and l2, respectively. Then, the first cylindrical lens is considered to contain multiple first cylindrical lens units with a length of l2 along its own length direction, and the second cylindrical lens is considered to contain multiple second cylindrical lens units with a length of l1 along its own length direction. A first cylindrical lens unit and the second cylindrical lens unit directly above it constitute a cylindrical lens unit. Each light-transmitting aperture on the aperture array layer corresponds one-to-one with each cylindrical lens unit, and the center of the light-transmitting aperture is located on the intersection line of the symmetry plane of the cylindrical lens unit and is close to the center of the bottom surface of the first cylindrical lens unit. The illumination area generated by the light beam through the light-transmitting aperture matches the cylindrical lens unit above it. The first cylindrical lens unit and the second cylindrical lens unit collimate the light passing through the light-transmitting aperture in two orthogonal directions.

[0014] Furthermore, the aperture of the light-transmitting aperture is less than 1 / 10 of the smaller of l1 and l2.

[0015] Furthermore, the ultrathin large-area uniform collimation backlight system also includes a counter-prism film, which is disposed above the second cylindrical lens array. The upper and lower surfaces of the counter-prism film are uniformly arranged with microprism structures of different periods to homogenize the light beam emitted from the orthogonal cylindrical lens array.

[0016] Furthermore, the placement angle and thickness of the opposing prism film are designed based on the spatial characteristics of its incident and emitted light, further homogenizing the light. The design parameters of the opposing prism film are its refractive index, thickness, and prism apex angle. Microprism structures with different periods are distributed on the upper and lower surfaces of the opposing prism film, with the same arrangement direction and prism apex angle. When the beam emitted from the orthogonal cylindrical lens array has a periodicity of D, an opposing prism film with a refractive index of n, a thickness of h, and a prism apex angle of 2θ is placed on the orthogonal cylindrical lens array. This allows the beam to be replicated into two beams of equal intensity along the arrangement direction of the microprism structures on the opposing prism film. The distance between the two light spots formed by the two beams projected onto the opposing prism film is... By selecting appropriate values ​​for n, h, and θ such that d = D / 2, the two light spots overlap, and the flawed parts coincide with the flawless parts, thus achieving the effect of homogenizing periodic flaws.

[0017] Furthermore, the aperture array layer is coated with a high-reflectivity film, which can reflect light beams that do not exit through the aperture back to the second and first prism films, and then emit them again through refraction and reflection by the prism films, thus achieving light energy reuse and improving energy utilization. Furthermore, the coated film includes, but is not limited to, materials with high reflectivity such as aluminum and chromium.

[0018] Furthermore, the light emitted by the uniform panel light source, after passing through the orthogonal prism film, the aperture array layer, the first cylindrical lens array, and the second cylindrical lens array, forms a uniform collimated beam with a divergence angle of less than ±15°. Specifically, the orthogonal prism film reduces the divergence angle of the light emitted by the uniform panel light source, the aperture array layer selects the light passing through the orthogonal prism film, and the light passing through the aperture enters the first cylindrical lens array. The remaining light is reflected back to the orthogonal prism film by a highly reflective material, further participating in light energy multiplexing through refraction and reflection. The first cylindrical lens array reduces the divergence angle of the light in one direction, and the second cylindrical lens array reduces the divergence angle of the light in another direction perpendicular to the aforementioned direction, making it a collimated beam with a divergence angle of less than ±15°.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] (1) The present invention adopts a structure of superimposing a film layer on a uniform panel light source. The structure is simple, the backlight thickness is small, and the cost is low. It overcomes the problems of complex processing, large size and high cost of existing three-dimensional display collimated backlights, and obtains an ultra-thin large-area uniform collimated backlight.

[0021] (2) The present invention uses an orthogonal prism film and a high reflectivity aperture array layer, which improves the light energy utilization rate of the backlight system through light energy reuse, overcomes the problem of low collimation backlight efficiency in existing three-dimensional displays, and achieves higher energy utilization rate. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of an ultra-thin, large-area uniform collimated backlight system for three-dimensional display, as an example of the present invention.

[0023] Figure 2 This is a partial aperture array layer structure diagram in an embodiment of the present invention;

[0024] Figure 3 This is a partial structural diagram of the first cylindrical lens array and the second cylindrical lens array in an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of a portion of the optical path structure in an embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of a partial optical path structure cross-section in an embodiment of the present invention.

[0027] Figure 6 This is a schematic diagram of the cross-section of the opposing prism membrane in an embodiment of the present invention.

[0028] Figure 7 This is a two-dimensional polar coordinate graph of the intensity of a light source with a divergence angle of 180° after passing through an orthogonal prism film in an embodiment of the present invention.

[0029] Figure 8 This is a simulation of the normalized illuminance distribution of the human retina in an embodiment of the present invention.

[0030] Figure 9 This represents the normalized intensity distribution of the beam divergence angle within a range of ±90° in this embodiment of the invention.

[0031] Figure 10 This is the normalized intensity distribution of the beam divergence angle within a range of ±5° in this embodiment of the invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below in conjunction with the accompanying drawings.

[0033] Figure 1 This is a schematic diagram of the structure of an ultra-thin, large-area, uniform collimated backlight system for three-dimensional display provided in an embodiment of the present invention. Figure 1 As shown, along the optical path, the ultra-thin large-area uniform collimated backlight system includes a uniform panel light source 101 with a large divergence angle, an orthogonal prism film 108, an aperture array layer 104, an orthogonal cylindrical lens array 109, and a opposing prism film 107. The orthogonal prism film 108 includes a first prism film 102 and a second prism film 103; the orthogonal cylindrical lens array includes a first cylindrical lens array 105 and a second cylindrical lens array 106. The edges of the first prism film 102 and the second prism film 103 are orthogonal to each other. The orthogonal prism film is used to reduce the divergence angle of the light emitted by the uniform panel light source 101. The aperture array layer 104 is an opaque film 201, and light-transmitting holes 202 are uniformly distributed in its row and column directions. The arrangement directions of the first cylindrical lens array 105 and the second cylindrical lens array 106 are orthogonal to each other and are located above the aperture array layer 104. The periods of the first cylindrical lens array 105 and the second cylindrical lens array 106 are the same as the row and column periods of the light-transmitting holes 202. The orthogonal cylindrical lens array further reduces the divergence angle of the light passing through the aperture array layer in two directions.

[0034] In this embodiment, the orthogonal prism film 108 is placed on a uniform panel light source with a large divergence angle. The uniform light emitted by the uniform panel light source with a large divergence angle of nearly 90° is incident on the orthogonal prism film, and the divergence angle of the outgoing light is compressed. The uniform panel light source 101 of the present invention can be selected as a direct-lit large-area uniform backlight or a side-lit large-area uniform backlight.

[0035] The design methods for the first and second prism films are the same, both designed based on the spatial angular distribution of their respective incident light to reduce the divergence angle of the outgoing light. The design parameters for the first and second prism films include the prism apex angle and the refractive index of the material. Let the prism apex angle be 2α, the incident light divergence angle be 2β, and the refractive index of the material be n. Using the law of refraction, the divergence angle of the outgoing light along the prism arrangement direction is calculated as follows: Therefore, the size of the prism apex angle and the refractive index of the material can be selected according to the required divergence angle of the emitted light.

[0036] Furthermore, the light rays emitted from the orthogonal prism film 108 are incident on the aperture array layer 104. Part of the light passes through the aperture 202, while the rest is reflected back to the orthogonal prism film 108 by the opaque film 201 (high-reflectivity film). The light rays then exit again through refraction and reflection by the orthogonal prism film 108. The light rays passing through the aperture array layer 104 pass through the first cylindrical lens array 105 and the second cylindrical lens array 106, and are collimated from the upper surface of the second cylindrical lens array 106. The opposing prism film 107 is positioned above the second cylindrical lens array 106, with its upper and lower surfaces uniformly arranged with microprism structures of different periods. A beam of light enters the lower surface of the opposing prism film 107, is refracted into two beams (left and right), and then passes through the upper surface of the opposing prism film 107, becoming two collimated beams, further homogenizing the light beam emitted from the orthogonal cylindrical lens array.

[0037] The first cylindrical lens array 105 is formed by arranging first cylindrical lenses 301 along one direction; the second cylindrical lens array 106 is formed by arranging second cylindrical lenses 302 along another direction orthogonal to the aforementioned direction; the second cylindrical lens array 106 is located above the first cylindrical lens array 105. After passing through the first and second cylindrical lens arrays, the light beam will be homogenized and collimated, so that the energy of the light beam emitted through the aperture array layer is uniformly distributed within a divergence angle of ±15°, preferably within a divergence angle of ±5°. The structural surface shape of the first and second cylindrical lenses is designed based on the spatial characteristics of their incident light and the set output light. According to the equal optical path condition, when the area of ​​the aperture array small hole is small enough to be approximated as a point light source, the cross-section of the two cylindrical lenses is chosen to be an ellipsoid, which allows the spherical wave to be converted into a cylindrical wave after passing through the first cylindrical lens, and the cylindrical wave to be converted into a plane wave after passing through the second cylindrical lens. However, since the area of ​​the aperture array pinhole cannot be approximated as a point light source, the light emitted from the edge of the pinhole becomes off-axis light, which cannot meet the equal optical path condition. Therefore, this invention can select a high-order aspherical surface as the cross section of the cylindrical lens unit to enable the system to achieve the effect of collimating light.

[0038] Let the widths of the first cylindrical lens 301 and the second cylindrical lens 302 be l1 and l2, respectively. Then, the first cylindrical lens 301 is considered to contain multiple first cylindrical lens units with a length of l2 along its own length direction, and the second cylindrical lens 302 is considered to contain multiple second cylindrical lens units with a length of l1 along its own length direction. A first cylindrical lens unit and the second cylindrical lens unit directly above it constitute a cylindrical lens unit. Each light-transmitting aperture 202 on the aperture array layer 104 corresponds one-to-one with each cylindrical lens unit, and the light-transmitting aperture 202 is located at the center of the bottom surface of its corresponding first cylindrical lens unit. The illumination area generated by the light beam through the light-transmitting aperture 202 matches the cylindrical lens unit. The first cylindrical lens unit and the second cylindrical lens unit collimate the light passing through the light-transmitting aperture 202 in two orthogonal directions.

[0039] In this invention, the size of the aperture 202 in the aperture array layer 104 is much smaller than the size of the cylindrical lens unit. Preferably, the aperture diameter of the aperture 202 is less than 1 / 10 of the smaller value between l1 and l2. According to the law of optical dilatation:

[0040] Etendue=n 2 ∫∫cos(θ)dAdΩ

[0041] In the formula, Etendue is the optical spread, n is the refractive index of the space, dA is the surface element on the optical surface, dΩ is the solid angle of the beam, and θ is the angle between the normal of the surface element and the central axis of the beam. In an ideal optical system where energy loss due to scattering and absorption is negligible, the optical spread of the beam is conserved after passing through the optical system. Therefore, the divergence angle of the beam after passing through an orthogonal cylindrical lens array is much smaller than the divergence angle of the beam entering the orthogonal cylindrical lens array through an aperture array layer.

[0042] Figure 2 This is a partial diagram of the aperture array layer structure in an embodiment of the present invention. Figure 2 As shown, the light-transmitting apertures 202 on the aperture array layer are uniformly arranged along the x and y directions, respectively.

[0043] Figure 3 This is a partial structural diagram of the first cylindrical lens array 105 and the second cylindrical lens array 106 in an embodiment of the present invention. Figure 3 As shown, the first cylindrical lens unit 301 and the second cylindrical lens unit 302 are arranged orthogonally.

[0044] Figure 4 This is a schematic diagram of a portion of the optical path structure in an embodiment of the present invention. For example... Figure 4 As shown, the cylindrical lens unit group 404 corresponds one-to-one with the aperture unit 401. The light rays after passing through the cylindrical lens unit group are modulated and collimated, pointing in the z direction.

[0045] In this embodiment, the first cylindrical lens unit 402 is a toroidal lens symmetrical about the yoz plane, and the second cylindrical lens unit 403 is a toroidal lens symmetrical about the xoz plane. The center of the aperture 405 of the aperture array layer 104 is located on the intersection line of the symmetry planes of the cylindrical lens unit group and is close to the center of the bottom surface of the first cylindrical lens unit 402; the second cylindrical lens unit 403 is placed directly on the first cylindrical lens unit 402. Ray 407 is a ray passing through the center of the aperture along the z-axis. Since the normal vectors of the upper and lower cylindrical lens units coincide with the z-axis at their center points, ray 407 can be directly collimated and emitted. The first cylindrical lens unit 402 modulates the angle of the ray in the x-direction, and the second cylindrical lens unit 403 modulates the angle of the ray in the y-direction. Ray 408 is a ray on the yoz plane. Since it does not contain an x-direction component, its direction does not change when exiting the first cylindrical lens unit 402, and it is refracted and collimated in the z-direction when exiting the upper cylindrical lens unit 403. Ray 409 is a ray in the xoz plane. Since it does not contain a y-direction component, its direction is refracted to be collimated in the z-direction when it exits the first cylindrical lens unit 402. Its direction remains unchanged when it passes through the second cylindrical lens unit 403. Ray 410 is an arbitrary ray, containing both x-direction and y-direction components. After refraction by the first cylindrical lens unit 402, the x-direction component of ray 410 is eliminated; after refraction by the second cylindrical lens unit 403, the y-direction component is eliminated, and it finally exits collimated in the z-direction.

[0046] Figure 5 This is a partial cross-sectional diagram of the optical path structure in an embodiment of the present invention. The left side shows the xoz cross-section, and the right side shows the yoz cross-section. Rays 503 and 504 passing through the aperture first pass through the corresponding lower cylindrical lens unit 501, then through the corresponding upper cylindrical lens unit 502, and are finally collimated and emitted. Ray 505 passing through the aperture is incident on the adjacent first cylindrical lens unit and is totally internally reflected; ray 506 passing through the aperture is incident on the adjacent second cylindrical lens unit and is also totally internally reflected.

[0047] Figure 6This is a schematic cross-sectional view of the opposing prism film in an embodiment of the present invention. Beam 602 passes through the opposing prism film 601 and is split into beams 603 and 604, exiting as beams. Therefore, after passing through the opposing prism film, the original light is split into two beams perpendicular to the prism edge direction, and the resulting exit pattern is equivalent to the original exit pattern being translated and superimposed in this direction. The translation distance depends on the material and thickness of the opposing prism film, designed based on the spatial characteristics of its incident light and the set exit light. The design parameters of the opposing prism film are its refractive index, thickness, and prism apex angle. Microprism structures with different periods are distributed on the upper and lower surfaces of the opposing prism film, with the same arrangement direction and prism apex angle. When the beam emitted from the orthogonal cylindrical lens array has a periodicity of D, an opposing prism film with a refractive index of n, a thickness of h, and a prism apex angle of 2θ is placed on the orthogonal cylindrical lens array. This allows the beam to be replicated into two beams of equal intensity along the arrangement direction of the microprism structures on the opposing prism film. The distance between the two light spots formed by the two beams projected onto the opposing prism film is... By selecting appropriate values ​​for n, h, and θ such that d = D / 2, the two light spots overlap, and the flawed parts coincide with the flawless parts, thus achieving the effect of homogenizing periodic flaws.

[0048] Figure 7 This is a two-dimensional polar coordinate graph of the intensity of a light source with a divergence angle of 180° after passing through an orthogonal prism film in an embodiment of the present invention. After most of the light rays pass through the orthogonal prism film, the angle is confined to the center, with an exit divergence angle of approximately 70°. Confining the beam energy within a certain divergence angle not only improves the light energy utilization efficiency but also reduces the impact of stray light on subsequent systems.

[0049] Figure 8 This embodiment of the invention simulates the normalized illuminance distribution received by the human retina. Light emitted by the system passes through a Fresnel lens with a focal length of 1m and enters the eye of a person at an observation distance of 1m, forming an image. The resolution grid size is set to be smaller than 1′ that the human eye can resolve, resulting in the following image: Figure 8 As can be seen, uniform illumination is presented on the human retina.

[0050] Figure 9 This is the normalized intensity distribution of the beam divergence angle within ±90° in this embodiment of the invention. It can be seen that after passing through this system, there are almost no rays with a divergence angle exceeding 5°, achieving collimation while virtually eliminating stray light.

[0051] Figure 10 This is the normalized intensity distribution of the beam divergence angle within ±5° in this embodiment of the invention. It can be seen that the full width at half maximum (FWHM) of the divergence angle in both the horizontal and vertical directions is less than 5°, achieving a good collimation effect.

[0052] In summary, this invention can achieve ultra-thin, large-area, uniform collimated backlighting based on traditional backlights, and is expected to be applied to fields such as 3D display, realizing the thinning and popularization of flat-panel 3D displays.

[0053] In this document, the terms “including,” “comprising,” or any other variations thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0054] In this document, the directional terms such as front, back, top, and bottom are defined based on the location of the components in the accompanying drawings and their relative positions to each other, solely for the purpose of clarity and convenience in expressing the technical solution. It should be understood that the use of these directional terms should not limit the scope of protection claimed in this application.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An ultra-thin, large-area, uniform collimated backlight system for three-dimensional displays, characterized in that, The system includes a uniform panel light source (101) arranged along the optical path direction, an orthogonal prism film composed of two layers of first prism film (102) and second prism film (103) arranged in upper and lower layers, an aperture array layer (104), and an orthogonal cylindrical lens array composed of two layers of first cylindrical lens array (105) and second cylindrical lens array (106). The orthogonal prism film is used to reduce the divergence angle of the light emitted by the uniform panel light source (101). The edges of the first prism film (102) and the second prism film (103) are orthogonal to each other. The aperture array layer (104) is an opaque film (201) with light-transmitting holes (202) evenly distributed in its row and column directions. The arrangement directions of the first cylindrical lens array (105) and the second cylindrical lens array (106) are orthogonal to each other and located above the aperture array layer (104). The periods of the first cylindrical lens array (105) and the second cylindrical lens array (106) are the same as the row and column periods of the light-transmitting holes (202). The orthogonal cylindrical lens array further reduces the divergence angle of the light passing through the aperture array layer in two directions and forms a large area of ​​uniform illumination.

2. The ultra-thin, large-area uniform collimated backlight system for three-dimensional display as described in claim 1, characterized in that, The ultrathin large-area uniform collimation backlight system also includes a counter-prism film (107), which is disposed above the second cylindrical lens array (106). The upper and lower surfaces of the counter-prism film are uniformly arranged with microprism structures of different periods to homogenize the light beam emitted from the orthogonal cylindrical lens array.

3. The ultra-thin, large-area uniform collimated backlight system for three-dimensional display as described in claim 1, characterized in that, The uniform panel light source (101) is a direct-lit large-area uniform backlight or a side-lit large-area uniform backlight.

4. The ultra-thin, large-area uniform collimated backlight system for three-dimensional display as described in claim 1, characterized in that, The design methods for the first and second prism films are the same; the design parameters for the first and second prism films include the prism apex angle and the refractive index of the material. Let the prism apex angle be 2α, the incident light divergence angle be 2β, and the refractive index of the material be n. Based on the law of refraction, the divergence angle of the outgoing light along the prism arrangement direction is calculated as follows: Therefore, the prism apex angle and material refractive index are selected based on the incident light divergence angle and the required outgoing light divergence angle.

5. The ultra-thin, large-area uniform collimated backlight system for three-dimensional display as described in claim 1, characterized in that, The first cylindrical lens array (105) is formed by arranging first cylindrical lenses (301) along one direction; the second cylindrical lens array (106) is formed by arranging second cylindrical lenses (302) along another direction orthogonal to the aforementioned direction; The second cylindrical lens array (106) is located above the first cylindrical lens array (105). After passing through the first and second cylindrical lens arrays, the light beam will be homogenized and collimated, so that the energy of the light beam emitted through the aperture array layer is evenly distributed within a divergence angle of ±15° after adjustment. The cross-sections of the first and second cylindrical lenses along their respective arrangement directions are high-order aspherical surfaces to achieve the effect of collimating the light rays.

6. The ultra-thin, large-area uniform collimated backlight system for three-dimensional display as described in claim 5, characterized in that, Let the widths of the first cylindrical lens (301) and the second cylindrical lens (302) be l1 and l2, respectively. Then, the first cylindrical lens (301) is considered to contain multiple first cylindrical lens units with a length of l2 along its own length direction, and the second cylindrical lens (302) is considered to contain multiple second cylindrical lens units with a length of l1 along its own length direction. A first cylindrical lens unit and the second cylindrical lens unit directly above it constitute a cylindrical lens unit. Each light-transmitting aperture (202) on the aperture array layer (104) corresponds one-to-one with each cylindrical lens unit, and the center of the light-transmitting aperture (202) is located on the intersection line of the symmetry plane of the cylindrical lens unit and is close to the center of the bottom surface of the first cylindrical lens unit. The illumination area generated by the light beam through the light-transmitting aperture (202) matches the cylindrical lens unit above it. The first cylindrical lens unit and the second cylindrical lens unit collimate the light passing through the light-transmitting aperture (202) in two orthogonal directions.

7. The ultra-thin, large-area uniform collimated backlight system for three-dimensional display as described in claim 6, characterized in that, The aperture of the light-transmitting aperture (202) is less than 1 / 10 of the smaller of l1 and l2.

8. The ultra-thin, large-area uniform collimated backlight system for three-dimensional display as described in claim 2, characterized in that, The placement angle and thickness of the opposing prism film (107) are designed based on the spatial characteristics of its incident light and the set output light, playing a role in further homogenizing the light. The design parameters of the opposing prism film are its refractive index, thickness, and prism apex angle. The upper and lower surfaces of the opposing prism film are respectively distributed with microprism structures of different periods. The microprism structures on the upper and lower surfaces are arranged in the same direction and have the same prism apex angle. When the beam emitted from the orthogonal cylindrical lens array has a defect with a period of D, the opposing prism film with a refractive index of n, a thickness of h, and a prism apex angle of 2θ is placed on the orthogonal cylindrical lens array, so that the beam is replicated into two beams of equal intensity along the arrangement direction of the microprism structures of the opposing prism film. The distance between the two light spots formed by the two beams projected on the opposing prism film is By selecting appropriate values ​​for n, h, and θ such that d = D / 2, the two light spots overlap, and the flawed parts coincide with the flawless parts, thus achieving the effect of homogenizing periodic flaws.

9. The ultra-thin, large-area uniform collimated backlight system for three-dimensional display as described in claim 1, characterized in that, The aperture array layer (104) is coated with a high reflectivity film, which can reflect the light beam that does not pass through the light aperture back to the second prism film (103) and the first prism film (102), and then emit it again through the refraction and reflection of the prism film, so as to realize the reuse of light energy and improve the energy utilization rate.

10. The ultra-thin, large-area uniform collimated backlight system for three-dimensional display as described in claim 1, characterized in that, The light emitted by the uniform panel light source (101) passes through the orthogonal prism film (108), the aperture array layer (104), the first cylindrical lens array (105), and the second cylindrical lens array (106) to form a uniform collimated beam with a divergence angle of less than ±15°. The orthogonal prism film (108) reduces the divergence angle of the light emitted by the uniform panel light source (101), the aperture array layer (104) selects the light passing through the orthogonal prism film (108), the light passing through the aperture will enter the first cylindrical lens array (105), and the remaining light will be reflected back to the orthogonal prism film by the high reflectivity material, and further participate in light energy reuse through refraction and reflection. The first cylindrical lens array reduces the divergence angle of the light in one direction, and the second cylindrical lens array reduces the divergence angle of the light in another direction perpendicular to the aforementioned direction, so that it becomes a collimated beam with a divergence angle of less than ±15°.

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