A projection stereo display device based on double-layer birefringent cylindrical lens

Abstract

The present invention proposes a projection stereoscopic display device based on a double-layer birefringent cylindrical lens. The projection stereoscopic display device based on a double-layer birefringent cylindrical lens is composed of a dense projector array and a double-layer birefringent cylindrical lens screen. The dense projector array is composed of multiple projectors, and the light of the projector projecting the image is linearly polarized light; the double-layer birefringent cylindrical lens screen is composed of a first birefringent cylindrical lens, a second birefringent cylindrical lens, a 1 / 4 wave plate and a screen. The dense projector array can project a parallax image onto the double-layer birefringent cylindrical lens screen, and the double-layer birefringent cylindrical lens screen can project the parallax image to different spatial directions to achieve stereoscopic display. The present invention can set multiple projectors with a small spacing in a small space range for image projection, and form a viewpoint arrangement with a large spacing.

Description

Technical Field

[0001] The present invention relates to display technology, and more particularly, to stereoscopic display technology. Background Art

[0002] Stereoscopic display technology is a display technology that can achieve the true reproduction of stereoscopic scenes. It can provide different parallax images for the human eye, so that people can have stereoscopic vision. Traditional stereoscopic projection devices can perform stereoscopic projection display through a single or multiple projectors. Usually, a single projector can achieve the stereoscopic display function through a double-refractive grating, but because the number of pixels provided by a single projector is limited, the resolution of the stereoscopic image is low; multiple projectors can achieve the stereoscopic display function through the principle of retroreflection, but the viewpoint position and the projector position should be consistent, so the size of the projection system is large. Therefore, the present invention proposes a projection stereoscopic display device based on a double-layer double-refractive cylindrical lens, which has a smaller volume and higher resolution than the traditional stereoscopic projection display device. Summary of the invention

[0003] The present invention proposes a projection stereoscopic display device based on a double-layer birefringent cylindrical lens. Figure 1 The structure diagram of the projection stereo display device based on the double-layer birefringent cylindrical lens is shown in FIG. The projection stereo display device based on the double-layer birefringent cylindrical lens is composed of a dense projector array and a double-layer birefringent cylindrical lens screen. The dense projector array can project parallax images onto the double-layer birefringent cylindrical lens screen, and the double-layer birefringent cylindrical lens screen can project parallax images into different spatial directions to achieve stereoscopic display.

[0004] Please refer to Figure 1 ,The dense projector array is composed of multiple projectors, and the light used by the projectors to project images is linearly polarized light.

[0005] Please refer to Figure 2The double-layer birefringent cylindrical lens screen is composed of a first birefringent cylindrical lens, a second birefringent cylindrical lens, a quarter wave plate and a screen. The first birefringent cylindrical lens is composed of a birefringent material and a fixed refractive index material. The birefringent material has a refractive index n1 for the linear polarized light projected by the projector, and a refractive index n2 for the linear polarized light orthogonal to the polarization direction of the projected light. The fixed refractive index material has a refractive index n2 for the light in all polarization directions. Therefore, it forms a cylindrical lens grating spectroscopic effect on the projected light, but has no refractive effect on the linear polarized light orthogonal to the polarization direction of the projected light. The second birefringent cylindrical lens is composed of a birefringent material and a fixed refractive index material. The birefringent material has a refractive index n3 for the linear polarized light projected by the projector, and a refractive index n4 for the linear polarized light orthogonal to the polarization direction of the projected light. The fixed refractive index material has a refractive index n3 for the light in all polarization directions. Therefore, it has no refractive effect on the projected light, but forms a cylindrical lens grating spectroscopic effect on the linear polarized light orthogonal to the polarization direction of the projected light. The 1 / 4 wave plate is placed in front of the screen. The angle between the polarization direction of the polarized light and the optical axis of the wave plate is 45°. The light projected by the projector becomes circularly polarized light after passing through the 1 / 4 wave plate.

[0006] For further information, please refer to Figure 3 , Figure 3 This is the image projection process of the present invention. During the image projection process, the light is sequentially projected to the screen through the first birefringent cylindrical lens and the 1 / 4 wave plate. In this process, the second birefringent cylindrical lens does not have a refracting effect on the projector's projected light, so it does not affect the propagation of the light. The light forms circularly polarized light after passing through the 1 / 4 wave plate.

[0007] For further information, please refer to Figure 4 , Figure 4 This is the image display process of the present invention. The projection light is reflected after reaching the screen, and the reflected light is sequentially projected to each viewpoint through a 1 / 4 wave plate and a second birefringent cylindrical lens. In this process, the circularly polarized light reflected by the screen is transformed into linearly polarized light after passing through a 1 / 4 wave plate, and the polarization direction is orthogonal to the polarization direction of the light projected by the projector, and the light can be projected by the second birefringent cylindrical lens. In this process, the first birefringent cylindrical lens does not have a refracting effect on the reflected light, so it does not affect the propagation of light.

[0008] For further information, please refer to Figure 2 , Figure 3 and Figure 4, because the first birefringent cylindrical lens and the second birefringent cylindrical lens can have different spatial positions, pitches, and focal length parameters, the position of the viewpoint formed after the light returns does not coincide with the position of the projector. Therefore, the present invention can set up multiple projectors with smaller spacing within a smaller space range to project images and form a viewpoint arrangement with larger spacing. Compared with a single projector to form a three-dimensional display device, the present invention has more projectors, so the resolution is higher; compared with a retroreflective three-dimensional display device formed by multiple projectors, because the position of the projector of the present invention no longer coincides with the viewpoint position, the dense projector array in the present invention can have a smaller size. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0010] Figure 1 It is a schematic diagram of the structure of the present invention.

[0011] Figure 2 Schematic diagram of the double-layer birefringent cylindrical lens screen of the present invention.

[0012] Figure 3 Schematic diagram of the projection light path of the present invention.

[0013] Figure 4 Schematic diagram of the display light path of the present invention.

[0014] Icons: 010-a projection stereoscopic display device based on a double-layer birefringent cylindrical lens; 100-a double-layer birefringent cylindrical lens screen; 200-a dense projector array; 101-a first birefringent cylindrical lens; 102-a second birefringent cylindrical lens; 103-a quarter wave plate; 104-a screen.

[0015] It should be understood that the above drawings are only schematic and are not drawn to scale. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0017] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0019] In the description of the embodiments of the present invention, it should be noted that the terms “first”, “second”, etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance. Example

[0020] Figure 1 The present invention provides a schematic diagram of the structure of a projection stereoscopic display device 010 based on a double-layer birefringent cylindrical lens. The projection stereoscopic display device based on a double-layer birefringent cylindrical lens is composed of a dense projector array 200 and a double-layer birefringent cylindrical lens screen 100. The dense projector array 200 can project a parallax image onto the double-layer birefringent cylindrical lens screen 100, and the double-layer birefringent cylindrical lens screen 100 can project the parallax image into different spatial directions to achieve stereoscopic display.

[0021] Please refer to Figure 1 The dense projector array 200 is composed of multiple projectors, and the light used by the projectors to project images is linearly polarized light.

[0022] Please refer to Figure 2 The double-layer birefringent cylindrical lens screen 100 is composed of a first birefringent cylindrical lens 101 , a second birefringent cylindrical lens 102 , a quarter wave plate 103 and a screen 104 .

[0023] The first birefringent cylindrical lens 101 is composed of a birefringent material and a fixed refractive index material. The birefringent material has a refractive index n1 for the linearly polarized light projected by the projector, and a refractive index n2 for the linearly polarized light orthogonal to the polarization direction of the projector light. The fixed refractive index material has a refractive index n2 for light in all polarization directions. Therefore, it forms a cylindrical lens grating splitting effect for the projector light, but has no refractive effect on the linearly polarized light orthogonal to the polarization direction of the projector light.

[0024] The second birefringent cylindrical lens 102 is composed of a birefringent material and a fixed refractive index material. The birefringent material has a refractive index n3 for the linear polarized light projected by the projector, and a refractive index n4 for the linear polarized light orthogonal to the polarization direction of the projector light. The fixed refractive index material has a refractive index n3 for light in all polarization directions, so it has no refractive effect on the projector light, but forms a cylindrical lens grating splitting effect on the linear polarized light orthogonal to the polarization direction of the projector light.

[0025] Since common liquid crystal molecules have a dual optical axis characteristic, the first birefringent cylindrical lens 101 and the second birefringent cylindrical lens 102 are formed by solidifying a liquid crystal material on a cylindrical lens plastic substrate to prepare a birefringent cylindrical lens. To achieve different refractive indices, the orientation vectors of the liquid crystal molecules are in different directions.

[0026] The quarter wave plate 103 is placed in front of the screen, and the angle between the polarization direction of the polarized light and the optical axis of the wave plate is 45°. The light projected by the projector becomes circularly polarized light after passing through the quarter wave plate 103 .

[0027] For further information, please refer to Figure 3 , Figure 3 This is the image projection process of the present invention. Each projector in the dense projector array 200 has a different spatial position, and each projector independently projects a parallax image. During the image projection process, the light from each projector is sequentially projected to the screen 104 through the first birefringent cylindrical lens 101 and the 1 / 4 wave plate 103. In this process, the second birefringent cylindrical lens 102 does not affect the propagation of the light because it does not have a refracting effect on the projector's projected light. Due to the splitting effect of the first birefringent cylindrical lens 101, the light projected by each projector will reach different positions on the screen, and the light will form circularly polarized light after passing through the 1 / 4 wave plate 103.

[0028] For further information, please refer to Figure 4 , Figure 4 This is the image display process of the present invention. The projection light is reflected after reaching the screen 104, and the reflected light is sequentially projected to each viewpoint through the 1 / 4 wave plate 103 and the second birefringent cylindrical lens 102. In this process, the circularly polarized light reflected by the screen 104 forms linearly polarized light after passing through the 1 / 4 wave plate 103, and the polarization direction is orthogonal to the polarization direction of the light projected by the projector, and the light can be projected by the second birefringent cylindrical lens 102. Since different projectors project light at different positions on the screen 104, the viewpoint positions formed after the reflection are also different. In this process, the first birefringent cylindrical lens 101 does not have a refracting effect on the reflected light, so it does not affect the light propagation.

[0029] Finally, the four projectors from left to right of the dense projector array 200 can project the parallax images provided by them to four viewpoints from left to right in the space. At the four viewpoints, the human eye can see four parallax images respectively.

[0030] Please refer to Figure 2 , Figure 3 and Figure 4 , because the first birefringent cylindrical lens 101 and the second birefringent cylindrical lens 102 have different spatial positions, pitches, and focal length parameters, according to the principle of similar triangles, because the second birefringent cylindrical lens 102 has a larger pitch and a smaller focal length relative to the first birefringent cylindrical lens 101, and its distance to the grating curtain 104 is smaller, the viewpoints formed after the light returns will have a larger spacing relative to each projector. Therefore, the present invention can set up multiple projectors with smaller spacing in a smaller space range for image projection, and form a viewpoint arrangement with larger spacing. Compared with a single projector to form a three-dimensional display device, the present invention has more projectors, so the resolution is higher; compared with a retroreflective three-dimensional display device formed by multiple projectors, because the projector position of the present invention no longer overlaps with the viewpoint position, the dense projector array in the present invention can have a smaller size.

Claims

1. A projection stereoscopic display device based on a double-layer birefringent cylindrical lens, characterized in that: The projection stereo display device based on double-layer birefringent cylindrical lens is composed of a dense projector array and a double-layer birefringent cylindrical lens screen; the dense projector array is composed of multiple projectors, and the light of the projector projecting the image is linearly polarized light; the double-layer birefringent cylindrical lens screen is composed of a first birefringent cylindrical lens, a second birefringent cylindrical lens, a 1 / 4 wave plate and the screen; the first birefringent cylindrical lens is composed of a birefringent material and a fixed refractive index material, the birefringent material has a refractive index n1 for the linear polarized light projected by the projector, and has a refractive index n2 for the linear polarized light orthogonal to the polarization direction of the projected light, and the fixed refractive index material has a refractive index n2 for the light in all polarization directions. 2; the second birefringent cylindrical lens is composed of a birefringent material and a fixed refractive index material, the birefringent material has a refractive index n3 for the linear polarized light projected by the projector, and has a refractive index n4 for the linear polarized light orthogonal to the polarization direction of the projected light, and the fixed refractive index material has a refractive index n3 for light in all polarization directions; a 1 / 4 wave plate is placed before the screen, and the angle between the polarization direction of the polarized light and the optical axis of the wave plate is 45°; the screen is placed at the end for light reflection; a dense projector array can project a parallax image onto a double-layer birefringent cylindrical lens screen, and the double-layer birefringent cylindrical lens screen can project the parallax image to different spatial directions to achieve stereoscopic display.

2. A projection stereoscopic display device based on a double-layer birefringent cylindrical lens as claimed in claim 1, characterized in that: The positions of the first birefringent cylindrical lens and the second birefringent cylindrical lens are interchanged.

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