A periodic light field stereoscopic display device

Abstract

In order to solve the problem that the traditional projection light field stereo display based on the non-coaxial optical system is difficult to form a periodic light field, the present application provides a periodic light field stereo display device.The periodic light field stereo display device is composed of a projector array and a one-dimensional retroreflective sheet array.The one-dimensional retroreflective sheet array is a projection screen, which is composed of a plurality of one-dimensional retroreflective sheets.The one-dimensional retroreflective sheet is composed of a composite structure formed by a cylindrical lens grating and a diffuse reflection layer, and can form one-dimensional retroreflection in a certain direction.The pitch of the cylindrical lens grating and the distance from the cylindrical lens grating to the diffuse reflection layer are set according to the distance from the one-dimensional retroreflective sheet to the projector array, so that the one-dimensional retroreflective sheets at different positions can form a completely consistent periodic light field pitch, and therefore the present application can construct a periodic light field.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of light field stereoscopic display, and more particularly, the application relates to a periodic light field stereoscopic display device. BACKGROUND

[0002] Taking a projection light field stereoscopic display device (patent number 2021115193543) as an example, in the projection light field stereoscopic display based on a non-coaxial optical system, the normal line of the stereoscopic image is no longer parallel to the normal line of the light splitting element, so that when the viewer moves away from the projection screen in a specific direction, the light field viewed by the viewer no longer changes, and therefore consistent stereoscopic images can be viewed by viewers in front and behind. However, the inter-viewpoint distance formed by the light splitting element is related to the distance from the light splitting element to the projector array, and the distance from the light splitting element at different positions on the projection screen to the projector array is different, so that the light splitting element with the same parameters cannot obtain the same inter-viewpoint distance, and therefore the periodic light field cannot be generated, and finally the viewer can only view the stereoscopic image from the main viewing area. The periodic light field can form a spatial light field consistent with the main viewing area outside the main viewing area, thereby effectively widening the viewing range of the display device.

[0003] To solve the problem that the traditional projection light field stereoscopic display based on a non-coaxial optical system is difficult to form a periodic light field, the application provides a periodic light field stereoscopic display device. SUMMARY

[0004] To solve the problem that the traditional projection light field stereoscopic display based on a non-coaxial optical system is difficult to form a periodic light field, the application provides a periodic light field stereoscopic display device.

[0005] The periodic light field stereoscopic display device is composed of a projector array and a one-dimensional retroreflective sheet array. The one-dimensional retroreflective sheet array is a projection screen, and each projector in the projector array projects a parallax image onto the one-dimensional retroreflective sheet array to form an image plane.

[0006] The one-dimensional retroreflective sheet array is composed of a plurality of one-dimensional retroreflective sheets. The one-dimensional retroreflective sheet serves as a light splitting element and can form one-dimensional retroreflection in a certain direction, that is, the light emitted by the projectors at different positions in the direction can be retroreflected by the one-dimensional retroreflective sheet and then converge again at their respective positions in the direction. The normal direction of the one-dimensional retroreflective sheet is consistent and not parallel to the normal line of the image plane. The normal direction of the one-dimensional retroreflective sheet is perpendicular to the direction in which the one-dimensional retroreflection is achieved.

[0007] The projectors in the projector array are densely arranged in any form, and each of the projectors projects a parallax image.

[0008] The one-dimensional retroreflective sheet is composed of a composite structure of a cylindrical lens grating and a diffuse reflection layer. The distance from the cylindrical lens grating to the projector along the normal direction of the one-dimensional retroreflective sheet is l 1, the focal length of the cylindrical lens grating is f , the period of the periodic light field formed by the cylindrical lens grating is p 1, the period of the cylindrical lens grating is p 2, and the distance from the cylindrical lens grating to the diffuse reflection layer is l 2 should satisfy p 2= p 1× l 2 / ( l 1 + l 2 ), and l 2 should be greater than or equal to f and less than 2 f .

[0009] Optionally, the one-dimensional retroreflective sheet is replaced by a slit grating instead of the cylindrical lens grating. Except for the focal length limitation condition, the slit period of the slit grating is p 2, and the distance from the slit grating to the diffuse reflection layer is l 2 should satisfy the same condition, i.e. p 2= p 1× l 2 / ( l 1 + l 2 ).

[0010] The technical principle for realizing the stereoscopic display is as follows:

[0011] The projectors in the projector array are densely arranged in any form. Each of the projectors projects an image onto the one-dimensional retroreflective sheet array to form an image plane. The light rays reach each of the one-dimensional retroreflective sheets on the one-dimensional retroreflective sheet array and are retroreflected by the one-dimensional retroreflective sheets. The light rays emitted by any one of the projectors are retroreflected and converge on a straight line, and the straight line is perpendicular to the normal direction of the one-dimensional retroreflective sheet and the one-dimensional retroreflective direction. It can be understood that the information on the straight line is from the same projector, and therefore the information on the straight line should be consistent. For any projector, the light rays emitted by the projector have the above-mentioned property, and the straight lines on which the light rays emitted by different projectors converge are arranged in parallel, thereby constructing a stereoscopic visual light field. When the human eye is in the stereoscopic visual light field, stereoscopic vision can be generated.

[0012] The technical principle for realizing the periodic light field is as follows:

[0013] If a periodic light field is formed, the light projected by any projector should form the same viewpoint spacing after exiting from two adjacent cylindrical lenses, that is, the periodic light field pitch. p 1. According to the principle of similar triangles, p 1= p 2×( l 1+ l 2) / l 2. The distance between the cylindrical lens grating and the projector along the normal direction of the one-dimensional retroreflective sheet at different positions on the projection screen is l 1 is different. If a one-dimensional retroreflective sheet with the same parameters is used, that is, the cylindrical lens grating pitch p 2 and the distance from the cylindrical lens grating to the diffuse reflection layer l 2 are exactly the same, because l 1 is different, then the viewpoint spacing formed for the one-dimensional retroreflective sheet at different positions is the periodic light field pitch. p 1 must be different, so it cannot form a periodic light field.

[0014] In the present invention, different cylindrical lens grating pitches are set for one-dimensional retroreflective sheets at different positions. p 2 and the distance from the cylindrical lens grating to the diffuse reflection layer l 2, and it satisfies p 2= p 1× l 2 / ( l 1+ l 2). Substitute this formula into p 1= p 2×( l 1+ l 2) / l 2 can be obtained p 1= p 1 , that is, a completely consistent periodic light field pitch can be formed for one-dimensional retroreflective sheets at different positions.

[0015] In summary, in the present invention, different cylindrical lens grating pitches are set for one-dimensional retroreflective sheets at different positions. p 2 and the distance from the cylindrical lens grating to the diffuse reflection layer l 2. For one-dimensional retroreflective sheets at different positions, completely consistent periodic light field pitches can be formed, thereby constructing a periodic light field. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention.

[0017] Figure 2 It is a schematic diagram of the principle of the present invention.

[0018] Figure 3 Schematic diagram of the positional relationship of different one-dimensional retroreflective sheets in the present invention.

[0019] Icons: 100 - image plane; 200 - one-dimensional retroreflective sheeting array; 300 - projector; 400 - one-dimensional retroreflective sheeting; 410 - first one-dimensional retroreflective sheeting; 420 - second one-dimensional retroreflective sheeting; 301 - adjacent cylindrical lens exit position; 401 - diffuse reflection layer; 402 - cylindrical lens grating.

[0020] It should be understood that the above drawings are merely schematic and not drawn to scale. DETAILED DESCRIPTION Example

[0021] Figure 1 This embodiment provides a periodic light field stereoscopic display device. The periodic light field stereoscopic display device is composed of a projector array and a one-dimensional retroreflective sheet array 200. The projector array is composed of projectors 300 in x’ The one-dimensional retroreflective sheeting array 200 is a projection screen, and each projector 300 in the projector array projects a parallax image onto the one-dimensional retroreflective sheeting array 200 to form an image plane 100 .

[0022] The one-dimensional retroreflective sheet array 200 is composed of a plurality of one-dimensional retroreflective sheets 400. The one-dimensional retroreflective sheet 400 can be used as a light splitting element. x One-dimensional retroreflection is formed in the direction, x and x’ Parallel. x’ The light emitted by the projectors at different positions in the direction can be reflected by the one-dimensional retroreflective sheet 400 and then x’ The normal direction of the one-dimensional retroreflective sheet 400 is z direction, which is consistent with the normal of the image plane k Parallel. The normal direction of the one-dimensional retroreflective sheeting is z Instead of achieving one-dimensional reverse reflection x vertical.

[0023] The projectors 300 in the projector array are densely arranged in any form, and each projector 300 projects a parallax image.

[0024] Please refer to Figure 2 The one-dimensional retroreflective sheet 400 is composed of a composite structure formed by a cylindrical lens grating 402 and a diffuse reflection layer 401. z The distance between the directional cylindrical lens grating 402 and the projector 300 is l 1. Cylindrical lens grating 402 focal length f5 mm, the pitch of the periodic light field formed by it p 1 is 603 mm, the pitch of the cylindrical lens grating 402 p 2 and the distance from the cylindrical lens grating 402 to the diffuse reflection layer 401 l 2 should satisfy p 2= p 1× l 2 / ( l 1 + l 2 ), wherein l 2=5 mm.

[0025] The technical principle of the present application for realizing stereoscopic display is:

[0026] Please refer to Figure 1 The projectors 300 in the projector array are densely arranged in any form. Each projector 300 projects an image onto the one-dimensional retroreflective sheet array 200 to form an image plane 100. The light rays reach each one-dimensional retroreflective sheet 400 on the one-dimensional retroreflective sheet array 200 respectively, and are retroreflected by the one-dimensional retroreflective sheet 400. After retroreflection, the light rays emitted by any one projector 300 converge on a straight line, which is in the direction y perpendicular to the normal direction of the one-dimensional retroreflective sheet z and the one-dimensional retroreflective direction x It can be understood that the information on the straight line comes from the same projector, so the straight line should have complete and consistent information. For any projector 300, the straight line where the light rays emitted by the projector 300 converge is parallel to the straight lines where the light rays emitted by other projectors 300 converge, thereby constructing a stereoscopic vision light field. When the human eye is in the stereoscopic vision light field, stereoscopic vision can be generated.

[0027] The technical principle of the present application for realizing a periodic light field is:

[0028] Please refer to Figure 2 If a periodic light field is formed, the light rays emitted by any one projector 300 are emitted along two adjacent cylindrical lenses, one light path returns to the position of the projector 300 after being emitted along the original cylindrical lens, and the other light path reaches the position 301 of the adjacent cylindrical lens after being emitted along the adjacent cylindrical lens, so that the same inter-viewpoint distance, i.e., the pitch of the periodic light field p 1, is formed. According to the principle of similar triangles, p 1= p 2×( l 1+ l 2) / l 2.

[0029] Please refer to Figure 3, the one-dimensional inverse reflection sheet at different positions on the projection screen along its normal direction z the distance from the cylindrical lens grating to the projector 300 l 1 is different, the first one-dimensional inverse reflection sheet 410 along its normal direction z the distance from the cylindrical lens grating to the projector l 1 is OVD1=1000 mm, and the second one-dimensional inverse reflection sheet 420 along its normal direction z the distance from the cylindrical lens grating to the projector l 1 is OVD2=1200 mm. If the one-dimensional inverse reflection sheet with the same parameters is used, that is, the cylindrical lens grating 402 pitch p 2 of the first one-dimensional inverse reflection sheet 410 and the second one-dimensional inverse reflection sheet 420 is 3 mm, because l 1 is different, then for the first one-dimensional inverse reflection sheet 410, the adjacent view point spacing p 1= p 2×(OVD1+ l 2) / l 2=603 mm, and for the second one-dimensional inverse reflection sheet 420, the adjacent view point spacing should be equal to p 1= p 2×(OVD2+ l 2) / l 2=723 mm, so it cannot form a periodic light field.

[0030] In the present application, for the one-dimensional inverse reflection sheet 400 at different positions, the different cylindrical lens grating 402 pitches p 2 are set, and it satisfies p 2= p 1× l 2 / ( l 1+ l 2), that is, for the first one-dimensional inverse reflection sheet 410 has p 2= p 1× l 2 / (OVD1+ l 2)=3 mm, and for the second one-dimensional inverse reflection sheet 420 has p 2= p 1× l 2 / (OVD2+ l 2)=2.502 mm. Substituting the p 2=3 mm of the first one-dimensional inverse reflection sheet 410 into p 1= p 2×(OVD1+ l 2) / l 2, the p 1=603 mm can be obtained; and substituting the p2=2.502mm p 1= p 2×(OVD2+ l 2) / l 2 after, also can get p 1=603 mm, therefore, the application to different position one-dimensional retroreflective sheeting 400 it can form the same periodic light field pitch.

[0031] In summary, in the application, because of the different position one-dimensional retroreflective sheeting 400, set different cylindrical lens grating 402 pitch p 2, then to different position one-dimensional retroreflective sheeting 400 it can form the same periodic light field pitch, thereby constructing the periodic light field.

Claims

1. A periodic light field stereoscopic display device, characterized in that: the periodic light field stereoscopic display device is composed of a projector array and a one-dimensional retroreflective sheet array; the one-dimensional retroreflective sheet array is a projection screen, and each projector in the projector array projects a parallax image onto the one-dimensional retroreflective sheet array to form an image plane; the one-dimensional retroreflective sheet array is composed of a plurality of one-dimensional retroreflective sheets; the one-dimensional retroreflective sheet functions as a light splitting element and can form one-dimensional retroreflection in a certain direction, that is, the light emitted by projectors at different positions in the direction can be retroreflected by the one-dimensional retroreflective sheet and then converge again at the respective positions in the direction; the normal direction of the one-dimensional retroreflective sheet is consistent and not parallel to the normal direction of the image plane; the normal direction of the one-dimensional retroreflective sheet is perpendicular to the direction in which the one-dimensional retroreflection is achieved; the projectors in the projector array are densely arranged in any form, and each projector projects a parallax image; The one-dimensional retroreflective sheet is composed of a composite structure of a cylindrical lens grating and a diffuse reflection layer; the distance from the cylindrical lens grating of the one-dimensional retroreflective sheet to a projector along the normal direction of the one-dimensional retroreflective sheet is l 1, the focal length of the cylindrical lens grating is f , the period of the periodic light field formed by the one-dimensional retroreflective sheet is p 1, the period of the cylindrical lens grating is p 2, and the distance from the cylindrical lens grating to the diffuse reflection layer is l 2 should satisfy p 2= p 1× l 2 / ( l 1+ l 2), and l 2 should be greater than or equal to f and less than 2 f ; Different column lens grating pitches are set for one-dimensional retro-reflective sheets at different positions p 2, then for one-dimensional retro-reflective sheets at different positions, a completely consistent periodic light field pitch can be formed, thereby constructing a periodic light field.

2. The periodic light field stereoscopic display device according to claim 1, characterized in that: the one-dimensional retroreflective sheet is replaced by a slit grating instead of a cylindrical lens grating; The slit grating has no focal length limitation condition, and its slit pitch p 2 and the distance from the column lens grating to the diffuse reflection layer l 2 satisfy the same condition, that is p 2= p 1× l 2 / ( l 1+ l 2).

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