Display device

Abstract

The present disclosure provides a display device comprising a display module and multiple Fresnel lenses disposed opposite a light-emitting surface of the display module. The central axes of the multiple Fresnel lenses coincide, and multiple sawtooth structures are disposed on both side surfaces of each Fresnel lens. The sawtooth structures have an effective surface and an ineffective surface, with the effective surfaces of any two adjacent surfaces of the multiple Fresnel lenses disposed in a one-to-one correspondence. For any two adjacent surfaces of the multiple Fresnel lenses, the radial dimension of at least one effective surface on the surface with a greater marginal ray height is greater than the radial dimension of the corresponding effective surface on the surface with a smaller marginal ray height, thereby reducing or eliminating light in displayed light that is directed toward the ineffective surface. This display device helps suppress stray light.

Description

Technical Field

[0001] The present disclosure belongs to the field of display technology, and particularly relates to a display device. Background Art

[0002] This section is intended to provide a background or context to the embodiments recited in the claims. No admission is made that anything herein is prior art by virtue of its inclusion in this section.

[0003] Fresnel lenses are commonly used in virtual reality displays. When light passes through the Fresnel surface of a Fresnel lens, a small amount of incident light inevitably passes through the ineffective edge. This light propagates disorderly within the system, ultimately forming stray light that interferes with the image. Summary of the Invention

[0004] The present disclosure provides a display device.

[0005] The present disclosure adopts the following technical solution: a display device comprising a display module and a plurality of Fresnel lenses arranged opposite to a light-emitting surface of the display module, wherein the central axes of the plurality of Fresnel lenses coincide with each other.

[0006] A plurality of sawtooth structures are provided on both side surfaces of each Fresnel lens, wherein the sawtooth structures have an effective surface and an ineffective surface, and the effective surfaces of any two adjacent surfaces of the plurality of Fresnel lenses are provided in a one-to-one correspondence;

[0007] For any two adjacent surfaces of the multiple Fresnel lenses, the radial dimension of at least one effective surface on the surface with a larger edge ray height is larger than the radial dimension of the corresponding effective surface on the surface with a smaller edge ray height, so as to reduce or eliminate the light in the displayed light that is directed toward the ineffective surface.

[0008] In some embodiments, the radial dimensions of the effective surfaces on the same side surface of the Fresnel lens are equal; for any two adjacent surfaces of the multiple Fresnel lenses, the ratio of the radial dimensions of the effective surfaces of the two surfaces is equal to the ratio of the marginal light heights of the two surfaces.

[0009] In some embodiments, on the surfaces of the multiple Fresnel lenses that are farthest from the display module, a radial dimension of an effective surface is in a range of 0.3 mm to 0.55 mm.

[0010] In some embodiments, the sawtooth structure on the same side surface of the same Fresnel lens is divided into a plurality of segments along the radial direction, the number of effective surfaces in the corresponding segments of any two surfaces is equal, and the radial dimensions of the effective surfaces of the sawtooth structure in the same segment on the same side surface of the same Fresnel lens are equal;

[0011] For any two adjacent surfaces of the plurality of Fresnel lenses, a ratio of radial dimensions of effective surfaces in at least one pair of corresponding segments is equal to a ratio of marginal ray heights of corresponding segments of the corresponding surfaces.

[0012] In some embodiments, radial dimensions of effective surfaces in the segments closest to the center of any two surfaces of the multiple Fresnel lenses are equal.

[0013] In some embodiments, in a segment closest to the center on the surface farthest from the display module, a radial dimension of the effective surface is in a range from 0.3 mm to 0.55 mm.

[0014] In some embodiments, on the surface of the plurality of Fresnel lenses that is the farthest from the light-emitting surface of the display module, the radial dimensions of the effective surface of the sawtooth structure are all equal; or,

[0015] On the surfaces of the multiple Fresnel lenses that are at the smallest distance from the light-emitting surface of the display module, radial dimensions of the effective surfaces of the sawtooth structures are all equal.

[0016] In some embodiments, at least one segment includes a plurality of sawtooth structures, or at least one segment includes a single sawtooth structure.

[0017] In some embodiments, the display device comprises a virtual reality display device.

[0018] In some embodiments of the present disclosure, on two adjacent surfaces of the Fresnel lens of the display device, the radial size of the effective surface on the surface with a larger edge ray height is also larger, so that less light enters the ineffective surface, reducing the stray light displayed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 2 is a light path diagram of a display device according to an embodiment of the present disclosure.

[0020] Figure 2a 1 is a front view of a single Fresnel lens in an embodiment of the present disclosure.

[0021] Figure 2b Shown is the definition of the radial dimension of the sawtooth structure of the Fresnel lens according to the embodiment of the present disclosure.

[0022] Figure 3a This is a design diagram of a sawtooth structure of adjacent Fresnel lenses in the related art.

[0023] Figure 3b This is a design diagram of the sawtooth structure of adjacent Fresnel lenses in an embodiment of the present disclosure.

[0024] Figure 4 2 is a light path diagram of a display device according to another embodiment of the present disclosure.

[0025] 1 , 2 , 3 , 4 , 5 , 6 , single-sided surfaces of the Fresnel lens; 2 , 3 , 4 , 5 , 6 , display module; 3 , pitch , radial dimension of the effective surface; 4 , 5 , 6 , edge ray heights. DETAILED DESCRIPTION

[0026] The present disclosure will be further described below with reference to the embodiments shown in the accompanying drawings.

[0027] Figure 1 2 is a light path diagram of a display device according to an embodiment of the present disclosure. Figure 4 2 is a light path diagram of a display device according to another embodiment of the present disclosure.

[0028] refer to Figure 1 and Figure 4 Some embodiments of the present disclosure provide a display device, including a display module P and a plurality of Fresnel lenses a, b, and c arranged opposite to a light-emitting surface of the display module P, wherein the central axes of the plurality of Fresnel lenses a, b, and c coincide.

[0029] Light emitted by display module P is refracted sequentially by Fresnel lens c, Fresnel lens b, and Fresnel lens a before entering the human eye. Display device P can be equipped with two display modules, one for displaying the left-eye image and the other for displaying the right-eye image. Two sets of Fresnel lenses are positioned opposite the two display modules P, corresponding one to the other. Figure 1 and Figure 4 What is shown is a set of Fresnel lenses and a corresponding display module P in a display device. The design of another set of Fresnel lenses and a corresponding display module P can be the same.

[0030] exist Figure 1 and Figure 4 In the illustrated embodiment, one display module P is configured with three Fresnel lenses. In other embodiments, one display module P may be configured with any suitable number of Fresnel lenses, such as two or four. This disclosure does not limit the number of Fresnel lenses in a Fresnel lens assembly.

[0031] Figure 2a 1 is a front view of a single Fresnel lens in an embodiment of the present disclosure. Figure 2bThis section shows the definition of the radial dimension, pitch, of the effective surface of the sawtooth structure of a Fresnel lens in an embodiment of the present disclosure. The radial dimension refers to the extension direction of the radius of the Fresnel lens, that is, the direction from the center of the Fresnel lens to the edge of the Fresnel lens. In this embodiment, the normal direction of the ineffective surface of the sawtooth structure is perpendicular to the central axis of the Fresnel lens, and the radial dimension, pitch, of the effective surface is equal to the radial spacing of the effective surface.

[0032] A plurality of sawtooth structures are provided on both side surfaces of each Fresnel lens, and the sawtooth structures have an effective surface and an ineffective surface. The effective surfaces on any two adjacent surfaces of the multiple Fresnel lenses are provided in a one-to-one correspondence. In practical applications, the vast majority of light directed toward the sawtooth structure is incident on one surface of the sawtooth structure, and it is hoped that all light directed toward the sawtooth structure is incident on this surface, which is called the effective surface of the sawtooth structure. The other surface of the sawtooth structure connected to the effective surface is called the ineffective surface. In practical applications, a small amount of light directed toward the sawtooth structure will be incident on the ineffective surface of the sawtooth structure, and it is hoped that the light directed toward the sawtooth structure will not be incident on the ineffective surface of the sawtooth structure at all.

[0033] The Fresnel lens in the disclosed embodiments is circular. On either side of the Fresnel lens, the surface of the central circular area can be a convex surface of any suitable shape, such as a conical surface or a spherical surface. The radius of the central circular area of ​​the Fresnel lens can be equal to or different from the radial dimension of the sawtooth structure. This disclosure does not limit the design of the surface of the central circular area of ​​the Fresnel lens.

[0034] Ideally, all light emitted from one effective surface will be incident on the corresponding next effective surface. Light emitted by the display module P enters the Fresnel lens through the effective surface with a sawtooth structure on one side of the lens, where it is refracted. The light then exits the Fresnel lens through the effective surface with a sawtooth structure on the other side of the lens, where it is refracted. It then travels to the effective surface with a sawtooth structure on the other side of the Fresnel lens, where it is refracted. It then travels to the effective surface with a sawtooth structure on the other side of the Fresnel lens. Finally, after multiple refractions, it enters the human eye.

[0035] For any two adjacent surfaces of the multiple Fresnel lenses, the radial dimension of at least one effective surface on the surface with a larger marginal ray height is larger than the radial dimension of the corresponding effective surface on the surface with a smaller marginal ray height.

[0036] The marginal ray height is the distance from the incident point of the ray to the surface to the central axis of the Fresnel lens. Figure 1The two side surfaces of Fresnel lenses a, b, and c are numbered 1 to 6, in descending order of distance from the light-emitting surface of display module P. The edge optical height of all light exiting on surface 1 is labeled y1. The edge optical height of all light exiting on surface 2 is labeled y2. The edge optical height of all light exiting on surface 2 is labeled y3. The edge optical height of all light exiting on surface 4 is labeled y4. The edge optical height of all light exiting on surface 5 is labeled y5. The edge optical height of all light exiting on surface 6 is labeled y6.

[0037] Figure 3a This is a design diagram of a sawtooth structure of adjacent Fresnel lenses in the related art. The inventors of this application are aware of some designs in which the radial dimensions of two corresponding effective surfaces on any two surfaces of a Fresnel lens assembly are equal. This helps simplify the manufacturing process of Fresnel lenses. However, since light is refracted at the effective surfaces, it is difficult to avoid that all displayed light passes through the effective surfaces. Continue to refer to Figure 3a When light is emitted from surface 2 to surface 3, part of the light is emitted to the invalid surface, thus forming stray light.

[0038] Figure 3b This is a design diagram of the sawtooth structure of adjacent Fresnel lenses in the embodiment of the present disclosure. The inventors of the present disclosure have found that if the height of the edge light on one of the two adjacent surfaces of the Fresnel lens group is larger, then the height of other light on this surface is also larger. Figure 3b For example, combined with Figure 1 and Figure 4 , light travels from an effective surface on surface 2 to an effective surface on surface 3. The edge ray height on surface 3 is greater than that on surface 2, and the ray heights at other locations on surface 3 are also greater than those on surface 2. If the radial dimensions of the effective surface on surface 3 are designed to be larger than the radial dimensions of the effective surface at the corresponding location on surface 2, then the light traveling from surface 2 to surface 3 is more likely to pass entirely through the effective surface on surface 3. This reduces the likelihood of light traveling to the ineffective surface. This design helps reduce or eliminate light traveling to the ineffective surface in the displayed light.

[0039] In some embodiments, the radial dimensions of the effective surfaces on the same side surface of the Fresnel lens are equal, and for any two adjacent surfaces of the plurality of Fresnel lenses, the ratio of the radial dimensions of the effective surfaces of the two surfaces is equal to the ratio of the marginal light heights of the two surfaces.

[0040] Overall, the probability of stray light appearing at the edges is higher. To simplify the Fresnel lens manufacturing process, the radial dimensions of the active surfaces of the sawtooth structures on the same side of the same Fresnel lens are equal. This also ensures that all light rays from one active surface to another are directed towards the other active surface.

[0041] The following table shows Figure 1 An example of a design scheme is shown. The radial dimension of the effective surface of the serrated structure on surface 1 is labeled p1, the radial dimension of the effective surface of the serrated structure on surface 2 is labeled p2, the radial dimension of the effective surface of the serrated structure on surface 3 is labeled p3, the radial dimension of the effective surface of the serrated structure on surface 4 is labeled p4, the radial dimension of the effective surface of the serrated structure on surface 5 is labeled p5, and the radial dimension of the effective surface of the serrated structure on surface 6 is labeled p6. The values ​​in the table are in mm.

[0042] y1 15.986 p1 0.500 y2 16.848 p2 0.527 y3 17.526 p3 0.548 y4 16.131 p4 0.505 y5 15.486 p5 0.479 y6 13.651 p6 0.422

[0043] The above data satisfy: y1 / y2=p1 / p2, y2 / y3=p2 / p3, y3 / y4=p3 / p4, y4 / y5=p4 / p5, y5 / y6=p5 / p6.

[0044] In some embodiments, the radial dimension of the active surface on the surface farthest from the display module P is in a range from 0.3 mm to 0.55 mm.

[0045] The smaller the radial dimension of the active surface, the more favorable it is for finely controlling the light output of the display module. However, if the radial dimension of the active surface is too small, it will increase the processing difficulty. The above radial dimension range of the active surface can balance fine control of light output and processing difficulty.

[0046] Continue to refer Figure 4 In some embodiments, the sawtooth structure on the same side surface of the same Fresnel lens is divided into a plurality of segments along the radial direction, the number of effective surfaces in the corresponding segments of any two surfaces is equal, and the radial sizes of the effective surfaces of the sawtooth structure in the same segment on the same side surface of the same Fresnel lens are equal;

[0047] For any two adjacent surfaces of the plurality of Fresnel lenses, a ratio of radial dimensions of effective surfaces in at least one pair of corresponding segments is equal to a ratio of marginal ray heights of corresponding segments of the corresponding surfaces.

[0048] The serrated structure on the same side surface of the same Fresnel lens is segmented from the inside out. The radial dimensions of the effective surface of the serrated structure within each segment are equal, which allows for a refined design of the optical path while effectively reducing stray light.

[0049] In some embodiments, radial dimensions of effective surfaces in the segments closest to the center of any two surfaces of the multiple Fresnel lenses are equal.

[0050] Combine Figure 4Because the propagation direction of light near the center of the Fresnel lens fluctuates relatively little, the probability of stray light appearing in these areas is also low. Therefore, the radial dimensions of the innermost consecutive sawtooth structures on each surface can be designed to be consistent. This can significantly simplify the Fresnel lens manufacturing process while also preventing the occurrence of stray light.

[0051] In some embodiments, in a segment closest to the center on the surface farthest from the display module, a radial dimension of the effective surface is in a range from 0.3 mm to 0.55 mm.

[0052] The smaller the radial dimension of the active surface, the more favorable it is for finely controlling the light output of the display module. However, if the radial dimension of the active surface is too small, it will increase the processing difficulty. The above radial dimension range of the active surface can balance fine control of light output and processing difficulty.

[0053] refer to Figure 4 In an exemplary embodiment, the Fresnel lens assembly includes Fresnel lens a, Fresnel lens b, and Fresnel lens c. Fresnel lens c is closest to display module P, and Fresnel lens a is farthest from display module P. The surfaces of the three Fresnel lenses a, b, and c are, from farthest to closest relative to the light-emitting surface of display module P, surface 1, surface 2, surface 3, surface 4, surface 5, and surface 6. The marginal ray height of surface 1 is y1, the marginal ray height of surface 2 is y2, the marginal ray height of surface 3 is y3, the marginal ray height of surface 4 is y4, the marginal ray height of surface 5 is y5, and the marginal ray height of surface 6 is y6.

[0054] Divide the light-emitting area of ​​Surface 1 into three equal segments along the radial direction. The innermost segment (segment 1 / 3) is a circular area with a radius of y1 / 3, containing the convex lens structure at the center of Surface 1 and several sawtooth structures. The second segment (segment 2 / 3) is an annular area with a width of y1 / 3, containing several sawtooth structures. The third segment (segment 3 / 3) is an annular area surrounding the second segment with a width of y1 / 3, containing several sawtooth structures.

[0055] The following table shows the radial distances from the outer boundaries of three segments on the surface of the side away from the display module P of the three Fresnel lenses to the center of each surface.

[0056]

[0057]

[0058] The following table shows the radial dimensions of the effective surfaces of the three segmented inner sawtooth structures on the six surfaces of the three Fresnel lenses.

[0059] Radial size 1 / 3 segment 2 / 3 section 3 / 3 section p1 0.5 0.5 0.500 p2 0.5 0.518 0.527 p3 0.5 0.536 0.548 p4 0.5 0.498 0.505 p5 0.5 0.468 0.479 p6 0.5 0.416 0.422

[0060] In this embodiment, the radial dimensions of the effective surfaces of the sawtooth structures on surface 1 are all equal. In other embodiments, the radial dimensions of the effective surfaces of the sawtooth structures on surface 6 can also be set to be all equal. This can simplify the manufacturing difficulty of the Fresnel lens.

[0061] In this embodiment, for the most central segment, the radial dimensions of the effective surfaces of the serrated structures on the six surfaces are all 0.5 mm. For the sub-central segment, the ratio of the radial dimensions of the effective surface of the serrated structure on surface 2 to the radial dimensions of the effective surface of the serrated structure on surface 1 is 0.518:0.5. Correspondingly, the ratio of the edge ray height of the sub-central segment on surface 2 to the edge ray height of the sub-central segment on surface 1 is also equal to 0.518:0.5. For the outermost segment, the ratio of the radial dimensions of the effective surface of the serrated structure on surface 2 to the radial dimensions of the effective surface of the serrated structure on surface 1 is 0.527:0.5. Correspondingly, the ratio of the edge ray height of the outermost segment on surface 2 to the edge ray height of the outermost segment on surface 1 is also equal to 0.527:0.5. The relationship between the radial dimensions of the effective surfaces of the serrated structures in different segments on the other two adjacent surfaces is the same and will not be repeated.

[0062] Figure 1 and Figure 4 The embodiment shown is Figure 3a Compared with the conventional design shown in the figure, the effective light efficiency is improved by 11.6%, and the problem of the display being cut by ineffective edges is alleviated. Figure 3a and Figure 3b What is shown is the reverse light path, that is, the light path from the human eye to the display module P.

[0063] It should be noted that, in order to more precisely control the light path, in extreme cases, the number of segments can also be set to be equal to the number of sawtooth structures. In this design, for example, the radial dimensions of the effective surfaces of the sawtooth structures on the surface closest to the display module P are equal, while the radial dimensions of the effective surfaces of the sawtooth structures on any other surfaces are gradually changing.

[0064] In other words, the aforementioned segments contain one sawtooth structure in the limit case, or at least one segment only contains one sawtooth structure.

[0065] In some embodiments, the display device comprises a virtual reality display device.

[0066] The various embodiments in the present disclosure are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0067] The scope of protection of the present disclosure is not limited to the above-described embodiments. Obviously, those skilled in the art may make various modifications and variations to the present disclosure without departing from the scope and spirit of the present disclosure. If such modifications and variations fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is intended to include such modifications and variations.

Claims

1. A display device comprising a display module and a plurality of Fresnel lenses disposed opposite to a light-emitting surface of the display module, wherein the central axes of the plurality of Fresnel lenses coincide with each other, wherein: A plurality of sawtooth structures are provided on both side surfaces of each Fresnel lens, wherein the sawtooth structures have an effective surface and an ineffective surface, and the effective surfaces of any two adjacent surfaces of the plurality of Fresnel lenses are provided in a one-to-one correspondence; For any two adjacent surfaces of the plurality of Fresnel lenses, the radial dimension of at least one effective surface on the surface with a larger marginal ray height is larger than the radial dimension of the corresponding effective surface on the surface with a smaller marginal ray height, so as to reduce or eliminate light in the displayed light that is directed toward the ineffective surface; For any two adjacent surfaces of the plurality of Fresnel lenses, the ratio of the radial dimensions of the two effective surfaces is equal to the ratio of the marginal light heights of the two surfaces.

2. The display device according to claim 1, wherein The radial sizes of the effective surfaces on the same side surface of the Fresnel lens are equal.

3. The display device according to claim 2, wherein: On the surfaces of the multiple Fresnel lenses that are farthest from the display module, the radial dimension of the effective surface is in the range of 0.3 mm to 0.55 mm.

4. The display device according to claim 1, wherein The sawtooth structure on the same side surface of the same Fresnel lens is divided into a plurality of segments along the radial direction, the number of effective surfaces in the corresponding segments of any two surfaces is equal, and the radial dimensions of the effective surfaces of the sawtooth structure in the same segment on the same side surface of the same Fresnel lens are equal; For any two adjacent surfaces of the plurality of Fresnel lenses, a ratio of radial dimensions of effective surfaces in at least one pair of corresponding segments is equal to a ratio of marginal ray heights of corresponding segments of the corresponding surfaces.

5. The display device according to claim 4, wherein: In the segments closest to the center of any two surfaces of the multiple Fresnel lenses, the radial sizes of the effective surfaces are equal.

6. The display device according to claim 5, wherein: In the segment closest to the center on the surface farthest from the display module, the radial dimension of the effective surface is in the range of 0.3 mm to 0.55 mm.

7. The display device according to claim 1, wherein On the surface of the plurality of Fresnel lenses that is the farthest from the light-emitting surface of the display module, the radial dimensions of the effective surface of the sawtooth structure are all equal; or, On the surfaces of the multiple Fresnel lenses that are at the smallest distance from the light-emitting surface of the display module, radial dimensions of the effective surfaces of the sawtooth structures are all equal.

8. The display device according to claim 4, wherein: At least one segment includes a plurality of sawtooth structures, or at least one segment includes one sawtooth structure.

9. The display device according to claim 1, wherein The display device includes a virtual reality display device.

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