Optical device and near-to-eye display device

Abstract

The invention provides an optical device and a near-to-eye display device. The optical device comprises a light guide part and a reflecting surface, the reflecting surface is obliquely arranged relative to the two parallel total internal reflecting surfaces of the light guide part so as to couple the light into the light guide part. The first end and the second end of the reflecting surface are respectively arranged on two opposite sides of the first total internal reflecting surface; the light-emitting diode further comprises an extinction surface which is located between the first total internal reflection surface and the reflection surface. According to the technical scheme, the reflecting mirror is obliquely arranged relative to the first total internal reflection surface, so that light rays entering the light guide part can be reflected to the position between the first total internal reflection surface and the second total internal reflection surface to be transmitted, meanwhile, due to the arrangement of the first end and the second end of the reflecting surface, the reflected light rays can be fully paved in the light guide part, and the light guide part is more compact. In addition, stray light can be eliminated through the extinction surface, and the effect of the light guide part in the process of achieving near-to-eye display is improved.

Description

[0001] The application is a divisional application, the original application has the application number of 202311331529.7, the application date is October 13, 2023, and the name is "optical device and near-eye display device". TECHNICAL FIELD

[0002] The application relates to the technical field of optics, in particular to an optical device and a near-eye display device. BACKGROUND

[0003] The application of different near-eye display systems such as AR (Augmented Reality) or VR (Virtual Reality) is becoming more and more common. However, in the above-mentioned near-eye display system, users have higher and higher technical requirements for products. Especially in the process of display, the quality requirement of the display image is also getting higher and higher. However, the current near-eye display system still has the problem that the light is not uniform and contains stray light when the light propagates through the light guide. SUMMARY

[0004] The application provides an optical device and a near-eye display device, which improves the propagation effect of light in the optical device and improves the display effect.

[0005] The application provides an optical device, which comprises a light guide and a reflecting surface, wherein, The light guide comprises first and second total internal reflection surfaces that are parallel to each other; the second total internal reflection surface has opposite light incident and exit ends; The reflecting surface is inclined relative to the first total internal reflection surface and is close to the light incident end; The first end of the reflecting surface is located on the side of the first total internal reflection surface away from the second total internal reflection surface, the second end of the reflecting surface is located between the first total internal reflection surface and the second total internal reflection surface, and the second end of the reflecting surface is spaced apart from the second total internal reflection surface by a set distance; Further comprising an extinction surface, the extinction surface is located between the first total internal reflection surface and the reflecting surface.

[0006] In the above technical solution, the reflecting mirror is inclined relative to the first total internal reflection surface, so that the light incident into the light guide can be reflected between the first and second total internal reflection surfaces for propagation. At the same time, through the arrangement of the first and second ends of the reflecting surface, the reflected light can be evenly distributed in the light guide, and the extinction surface can eliminate stray light, thereby improving the effect of the light guide in the display of the near-eye display.

[0007] In one specific implementation, the first end and the second end of the reflecting surface satisfy: The light rays within the incident angle are light rays entering the optical device through the light ray incident end, then reflected once by the reflecting surface to the second total internal reflection surface, and spread on the light guide to achieve total internal reflection propagation; wherein the incident angle is at least 50% of the maximum incident angle; The edge light rays obliquely incident to the second end of the reflecting surface are reflected to the first end of the reflecting surface and the first total internal reflection surface after being reflected twice by the reflecting surface.

[0008] In one specific implementation, it further includes an extinction surface, one end of the extinction surface is connected with the first end of the reflecting surface, and the other end is fixedly connected with the first total internal reflection surface close to one end of the reflecting surface, and is used for absorbing light rays reflected twice by the reflecting surface.

[0009] In one specific implementation, the extinction surface is a black light-absorbing surface or a rough surface; wherein, When the extinction surface is a rough surface, the roughness of the rough surface is greater than the roughness of the reflecting surface.

[0010] In one specific implementation, the extinction surface is arranged obliquely relative to the first total internal reflection surface, and the extinction surface and the first total internal reflection surface form an obtuse angle.

[0011] In one specific implementation, it further includes a connecting surface, one end of the connecting surface is connected with the second end of the reflecting surface, and the other end is connected with the second total internal reflection surface close to one end of the reflecting surface.

[0012] In one specific implementation, it further includes a polyhedral structure, the reflecting surface, the extinction surface, and the connecting surface are surfaces of the polyhedral structure; The polyhedral structure is adhesively connected with the light guide.

[0013] In one specific implementation, the length direction of the first total internal reflection surface is the first direction; The distance L between the end point of the first total internal reflection surface close to the reflecting surface and the second end of the reflecting surface in the first direction satisfies: ; and ; wherein, H is the vertical distance between the second end of the reflecting surface and the second total internal reflection surface; b is the included angle between the reflecting surface and the second total internal reflection surface; a is the angle of one half of the maximum incident angle. d is the vertical distance between the first total internal reflection surface and the second total internal reflection surface; k, l are redundancy amounts.

[0014] In one specific implementation, the length direction of the first total internal reflection surface is the first direction; The distance L between the end point of the reflection surface close to the first total internal reflection surface and the second end of the reflection surface in the first direction satisfies: ; ; H is the vertical distance between the second end of the reflection surface and the second total internal reflection surface; b is the included angle between the reflection surface and the second total internal reflection surface; a is the angle of one half of the maximum incident angle; d is the vertical distance between the first total internal reflection surface and the second total internal reflection surface; j is a coefficient, and 50%≤j≤1.

[0015] In one specific implementation, the length direction of the first total internal reflection surface is the first direction; The distance L between the end point of the reflection surface close to the first total internal reflection surface and the second end of the reflection surface in the first direction satisfies: ; ; H is the vertical distance between the second end of the reflection surface and the second total internal reflection surface; b is the included angle between the reflection surface and the second total internal reflection surface; a is the angle of one half of the maximum incident angle; d is the vertical distance between the first total internal reflection surface and the second total internal reflection surface; j is a coefficient, and 50%≤j≤1. k, l are redundancy amounts.

[0016] In a second aspect, a near-eye display device is provided, comprising a light ray generator, and the optical device of any one of the above; wherein, The light rays generated by the light ray generator are incident into the light guide only at the light ray incident end.

[0017] In the technical solution, the mirror is arranged obliquely relative to the first total internal reflection surface, so that the light incident into the light guide member is reflected between the first total internal reflection surface and the second total internal reflection surface for propagation. Meanwhile, the first end and the second end of the reflection surface are arranged, so that the reflected light can be spread in the light guide member, thereby achieving uniform arrangement of the light. In addition, stray light can be eliminated by the light elimination surface, thereby improving the optical performance of the optical device and improving the effect of the light guide member in the display for near-eye display. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 An application scenario of the optical device provided by the embodiment of the present application is shown in the figure. Figure 2 An incident angle of the optical device provided by the embodiment of the present application is shown in the figure. Figure 3 A structure of the optical device provided by the embodiment of the present application is shown in the figure. Figure 4 A propagation of the light in the optical device provided by the embodiment of the present application is shown in the figure. Figure 5 Another propagation of the light in the optical device provided by the embodiment of the present application is shown in the figure. Figure 6 Another propagation of the light in the optical device provided by the embodiment of the present application is shown in the figure. Figure 7 Another propagation of the light in the optical device provided by the embodiment of the present application is shown in the figure. Figure 8 A specific structure of the optical device provided by the embodiment of the present application is shown in the figure. Figure 9 Another specific structure of the optical device provided by the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings.

[0020] It should be noted that the technical terms or scientific terms used in the one or more embodiments of the present disclosure should be understood as the general meaning understood by a person skilled in the art to which the present disclosure belongs, unless otherwise defined. The terms "first", "second", and the like used in the one or more embodiments of the present disclosure do not represent any order, number, or importance, but are only used to distinguish different components. The terms "include", "contain", and the like mean that the elements or objects before the terms cover the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and the like are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "up", "down", "left", "right", and the like are only used to represent relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships may also change accordingly.

[0021] To facilitate the understanding of the optical device provided by the embodiments of the present application, the application scenario thereof is first described. The optical device provided by the embodiments of the present application is applied in an AR (Augmented Reality) or VR (Virtual Reality) device. In the current optical waveguide, light rays are prone to uneven propagation, which affects the display effect of the AR or VR device. Therefore, the embodiments of the present application provide an optical device to improve the light propagation effect of the optical device, thereby improving the display effect of the AR or VR device. The specific embodiments will be described in detail below with reference to the accompanying drawings.

[0022] Reference Figure 1 , Figure 1 The application scenario of the optical device provided by the embodiments of the present application is shown. In the application scenario of the embodiments of the present application, the light rays emitted by the light ray generator 200 enter the light guide 110 in the optical device 100, and are coupled into the light guide 110 between the two total internal reflection surfaces of the light guide 110 by the reflecting surface 120 of the optical device 100 to propagate the light rays by total internal reflection, and are coupled out of the light guide 110 by the coupling-out element 130 in the light guide 110 to propagate to the user's eyes. The light rays emitted by the light ray generator 200 can be collimated images. For example, the light ray generator 200 can be an optical collimator device, or can also be a light source generator component with scanning properties, which is not limited in the embodiments of the present application.

[0023] To facilitate the description of the optical device 100 provided by the embodiments of the present application, the maximum incident angle is first defined. When the light ray generator 200 emits to the optical device 100, the maximum angle of the light ray generator 200 incident into the optical device 100 is defined as the maximum incident angle. For example, Figure 2The reference ray shown, the edge rays emitted by the ray generator 200 form the maximum incident angle to the optical device 100, that is, the maximum incident angle is determined by the edge rays of the ray generator 200 (e.g., Figure 2 The angle α shown is the angle formed by the two edge rays. Additionally, in Figure 2 The example also illustrates the angle of incidence, such as... Figure 2 The incident angle β is shown as an example of the dashed line, where β ≤ α. Figure 2 The example also shows half the angle α of the maximum incident angle, where α = 1 / 2α, which is the angle obtained by dividing the angle by the angle bisector of the maximum incident angle.

[0024] refer to Figure 3 , Figure 3 A schematic diagram of the structure of an optical device provided in an embodiment of this application is shown. The main structure of the optical device provided in this application includes a light guide 110 and a reflecting surface 120. The light guide 110 has a first total internal reflection surface 111 and a second total internal reflection surface 112 that are parallel to each other. Figure 1 As shown, the second total internal reflection surface 112 is located on the side closer to the light generator 200, while the first total internal reflection surface 111 is located on the side of the second total internal reflection surface 112 away from the light generator 200. When light propagates in the light guide 110, the light can be totally internally reflected between the first total internal reflection surface 111 and the second total internal reflection surface 112 to achieve the propagation of light.

[0025] When light is incident, the light guide 110 has a light incident end and a light exit end ( ). Figure 3 For details not marked, please refer to the following: Figure 1 (The positions of the light incident and light exit points). Specifically, the light incident and light exit points are arranged along the length of the light guide 110 and located at opposite ends of the second total internal reflection surface 112. Light rays incident from the light incident point into the light guide 110 can be coupled through the reflecting surface 120 to undergo total internal reflection between the first total internal reflection surface 111 and the second total internal reflection surface 112.

[0026] When forming the reflective surface 120, it can be formed by directly coating the reflective layer on the light guide 110, or by attaching the reflective layer to the light guide 110 as the reflective surface 120. In the embodiments of this application, no specific limitation is made, as long as light can be coupled between the first total internal reflection surface 111 and the second total internal reflection surface 112.

[0027] In the specific configuration of the reflective surface 120, the reflective surface 120 is inclined relative to the length direction of the light guide 110, that is, the reflective surface 120 is inclined relative to the first total internal reflective surface 111. In addition, since the reflective surface 120 serves as a coupling device, it is positioned near the light incident end to ensure that the light can be reflected by the reflective surface 120 to the space between the first total internal reflective surface 111 and the second total internal reflective surface 112, thereby achieving light coupling.

[0028] When the reflecting surface 120 is tilted relative to the first total internal reflecting surface 111, the reflecting surface 120 has a first end O1 and a second end O2, where the first end O1 is the high end and the second end O2 is the low end. Specifically, the extension lines of the reflecting surface 120 and the first total internal reflecting surface 111 (e.g., Figure 3 As shown by the dashed lines in the diagram, there is an intersection point. The first end O1 and the second end O2 of the reflective surface 120 are located on opposite sides of the extension line of the first total internal reflective surface 111. The first end O1 of the reflective surface 120 is located on the side of the first total internal reflective surface 111 away from the second total internal reflective surface 112; it can also be understood that the first end O1 protrudes outward from the first total internal reflective surface 111. The second end O2 of the reflective surface 120, as the lower end, is located between the first total internal reflective surface 111 and the second total internal reflective surface 112, and there is a set distance between the second end O2 of the reflective surface 120 and the second total internal reflective surface 112, meaning that the second end O2 of the reflective surface 120 and the second total internal reflective surface 112 do not intersect. Figure 3 The placement direction of the light guide 110 is the reference direction. The first end O1 and the second end O2 of the reflective surface 120 are set in a left-high and right-low manner so that the reflection direction of the reflective surface 120 faces the interior of the light guide 110 and the light reflected by the reflective surface 120 can enter the light guide 110.

[0029] In addition, the optical device includes two exposed surfaces for connecting the reflecting surface 120 to two total internal reflecting surfaces (first total internal reflecting surface 111 and second total internal reflecting surface 112). For example, one of the exposed surfaces is an extinction surface 114, located between the first total internal reflecting surface 111 and the reflecting surface 120, and used to connect the first total internal reflecting surface 111 and the reflecting surface 120. For example, one end of the extinction surface 114 is connected to the first end O1 of the reflecting surface 120, and the other end is fixedly connected to the end of the first total internal reflecting surface 111 near the reflecting surface 120, and is used to absorb light reflected twice by the reflecting surface 120 to the area between the first end O1 of the reflecting surface 120 and the first total internal reflecting surface 111, i.e., absorbing light reflected twice by the reflecting surface 120. The light reflected by the reflecting surface 120 to both sides is stray light in the light guide 110.

[0030] The light extinction surface 114 can be configured in different ways. For example, the light extinction surface 114 can be a black light absorption surface or a rough surface. When the light extinction surface 114 is a black light absorption surface, the light absorption function of the black surface can be used to absorb light, thereby reducing the reflection of light. When the light extinction surface 114 is a rough surface, the roughness of the rough surface is greater than the roughness of the reflective surface 120, so that the diffuse reflection formed by the rough surface reduces the light entering between the first total internal reflection surface 111 and the second total internal reflection surface 112. It should be understood that the light extinction in this application does not mean that the light is eliminated, but that the light is reduced from propagating between the first total internal reflection surface 111 and the second total internal reflection surface 112 by absorbing light or diffuse reflection, transmission, etc.

[0031] Another exposed surface is located between the second total internal reflection surface 112 and the reflective surface 120, and serves as a connecting surface 113 to connect the second total internal reflection surface 112 and the reflective surface 120. For example, one end of the connecting surface 113 is connected to the second end O2 of the reflective surface 120, and the other end of the connecting surface 113 is connected to the end of the second total internal reflection surface 112 close to the second end O2 of the reflective surface 120. The connecting surface 113 can also be a light extinction surface, thereby reducing the reflection of light incident thereon to reduce stray light entering between the first total internal reflection surface 111 and the second total internal reflection surface 112. When the connecting surface 113 is a light extinction surface, reference can be made to the description of the light extinction surface above, which will not be described here.

[0032] It should be understood that when the first total internal reflection surface 111, the second total internal reflection surface 112, and the reflective surface 120 are connected, it is not limited to the two exposed surfaces described above, and other exposed surfaces can also be used to connect the first total internal reflection surface 111, the second total internal reflection surface 112, and the reflective surface 120. For example, the first total internal reflection surface 111 and the reflective surface 120 are connected by two or three exposed surfaces; the second total internal reflection surface 112 and the reflective surface 120 are connected by two or three exposed surfaces. For ease of description, in the embodiments of the present application, the first total internal reflection surface 111, the second total internal reflection surface 112, and the reflective surface 120 are connected by the light extinction surface 114 and the connecting surface 113 as an example.

[0033] For ease of description, the intersection of the light extinction surface 114 and the first total internal reflection surface 111 is defined as point O3, and the intersection of the reflective surface 120 and the connecting surface 113 is defined as point O2.

[0034] When the reflective surface 120 couples light between the first total internal reflection surface 111 and the second total internal reflection surface 112, to improve the uniformity of the light, the reflective surface 120 needs to cooperate with both the first total internal reflection surface 111 and the second total internal reflection surface 112. Specifically, the first and second ends of the reflective surface 120 satisfy the following: light rays within the incident angle that enter the optical device 100 through the light incident end are reflected once again by the reflective surface 120 to the second total internal reflection surface 112, and then cover the light guide 111 to achieve total internal reflection propagation. The incident angle can be referenced... Figure 2 The angle β is the incident angle. In this embodiment, the incident angle is at least 50% of the maximum incident angle. For example, β can be 50% of the maximum incident angle, 70% of the maximum incident angle, 90% of the maximum incident angle, or 100% of the maximum incident angle. When light rays within the above-mentioned incident angle are coupled into the space between the first total internal reflection surface 111 and the second total internal reflection surface 112 via the reflecting surface 120, the light rays completely cover the light guide 110.

[0035] For example, with Figure 4 Taking the propagation of light as an example, Figure 4 A schematic diagram is shown illustrating the interaction of light rays between the first total internal reflection surface 111 and the second total internal reflection surface 112 via the reflecting surface 120.

[0036] When light rays perpendicular to the second total internal reflection surface 112 are incident on the optical device 100, the light rays have a certain aperture. When the light rays are incident on the reflecting surface 120, edge rays that limit the aperture appear. For example, the dashed lines with arrows and the solid lines with arrows represent the edge rays, respectively. For ease of description, the edge ray indicated by the dashed lines with arrows is named the first edge ray S1, and the edge ray indicated by the solid lines with arrows is named the second edge ray S2.

[0037] First, let's describe the first edge ray S1. The first edge ray S1 is incident on the reflective surface 120 near the second end O2. After being reflected by the reflective surface 120, it is reflected to the second total internal reflection surface 112. Then, it is reflected by the second total internal reflection surface 112 to the intersection point (point O3) of the first total internal reflection surface 111 and the extinction surface 114. At this time, point O3, as the endpoint of the first total internal reflection surface 111, has the property of total internal reflection. The first edge ray S1 is reflected by the first total internal reflection surface 111 to the second total internal reflection surface 112 at point O3, and propagates between the first total internal reflection surface 111 and the second total internal reflection surface 112 in the manner of total internal reflection.

[0038] The second edge light S2 is incident on the reflecting surface 120 near the first end O1, is reflected by the reflecting surface 120, and is reflected to the intersection point (point O3) of the first total internal reflection surface 111 and the light extinction surface 114, and continues to propagate to the second total internal reflection surface 112 and continues to propagate between the first total internal reflection surface 111 and the second total internal reflection surface 112 in a total internal reflection manner.

[0039] As can be seen from the above description, when the first edge light S1 and the second edge light S2 enter between the first total internal reflection surface 111 and the second total internal reflection surface 112 for total internal reflection after propagating to the point O3, the first edge light S1 and the second edge light S2 substantially overlap, and other lights located between the first edge light S1 and the second edge light S2 also propagate in the light guide 110 between the first edge light S1 and the second edge light S2. In this case, it can be considered that the light substantially completely fills inside the light guide 110, and if the light intensity is detected on the second total internal reflection surface 112, substantially the entire second total internal reflection surface 112 is illuminated by the coupled light. This state is also referred to as the light filling the light guide 110, thereby improving the uniformity of the light propagating in the light guide 110.

[0040] When the optical device propagates light, on the one hand, the uniformity of the light during propagation needs to be met, and on the other hand, stray light needs to be eliminated to improve the effect of the light guide 110 during light propagation. The so-called stray light refers to light that does not meet the total internal reflection requirement when propagating between the first total internal reflection surface 111 and the second total internal reflection surface 112. Referring to Figure 5 two different lights are shown in Figure 5 , which are light S3 and light S4, wherein S3 is stray light. During light propagation, light S3 is light that enters between the first total internal reflection surface 111 and the second total internal reflection surface 112 after being reflected by the reflecting surface 120 twice, that is, light S3 is reflected by the reflecting surface 120 to the second total internal reflection surface 112, is reflected by the second total internal reflection surface 112 to the reflecting surface 120, and is reflected by the reflecting surface 120 to between the first total internal reflection surface 111 and the second total internal reflection surface 112. Light S4 is light that enters between the first total internal reflection surface 111 and the second total internal reflection surface 112 after being reflected by the reflecting surface 120 once. By comparing light S3 and light S4, it can be seen that the reason for the generation of stray light is that the light is reflected by the reflecting surface 120 multiple times, so that when it enters between the first total internal reflection surface 111 and the second total internal reflection surface 112, it does not meet the requirement of the total internal reflection angle (referring to light S3 and light S4), and such light becomes stray light.

[0041] Referring to light rays S3 and S4, when the incident point of light ray S3 is close to the intersection point O2 of the reflecting surface 120 and the connecting surface 113, it is easy to see the following: Figure 5 Similar cases of reflection by a reflective surface more than 120 times (in) Figure 5 (The light is reflected twice). In this case, the reflected light will form stray light when it enters between the first total internal reflection surface 111 and the second total internal reflection surface 112. Therefore, the intersection point O3 of the extinction surface 114 and the first total internal reflection surface 111 needs to be low enough to eliminate some of the stray light from the secondary reflection (in this application, secondary reflection and multiple reflections refer to two or more reflections by the reflected surface 120) through the extinction surface 114. At the same time, the intersection point O2 of the reflecting surface 120 and the connecting surface 113 also needs to have a certain height to ensure that the stray light does not cross the boundary between the first total internal reflection surface 111 and the extinction surface 114 and enter the light guide 110.

[0042] Therefore, when setting the reflective surface 120 provided in this application embodiment, the first end and the second end of the reflective surface 120 should satisfy the following: the edge light rays obliquely incident on the second end O2 of the reflective surface 120 within the incident angle are reflected twice by the reflective surface 120 and then reflected to the space between the first end O1 of the reflective surface 120 and the first total internal reflection surface 111. That is, after the light rays within the incident angle are reflected multiple times by the reflective surface 120, the stray light can be prevented from entering the space between the first total internal reflection surface 111 and the second total internal reflection surface 112 by the setting of the reflective surface 120, thereby filtering out the stray light. The specific filtering method is absorption by the extinction plane or diffuse reflection, as mentioned above.

[0043] As can be seen from the above description, the optical device provided in this application embodiment, by employing a reflective surface 120 that is tilted relative to the first total internal reflection surface 111, can reflect light incident on the light guide 110 to propagate between the first total internal reflection surface 111 and the second total internal reflection surface 112. Furthermore, considering the propagation effect of light in the optical device, the arrangement of the first end O1 and the second end O2 of the reflective surface 120 allows the reflected light to spread evenly throughout the light guide 110, thereby achieving uniform light distribution. Additionally, it can filter out stray light reflected multiple times by the reflective surface 120, thereby improving the optical performance of the optical device and enhancing the effect of the light guide 110 in achieving near-eye display.

[0044] When specifically setting the first end O1 and the second end O2 of the reflective surface 120, it is related to parameters such as the thickness of the light guide 110, the tilt angle of the reflective surface 120, and the intersection point of the first total internal reflection surface 111 and the extinction surface 114.

[0045] refer to Figure 6 As shown, in Figure 6Some parameters related to the reflecting surface 120 are defined in the following. First, the parameters in Figure 6 are explained. In the parameters, O2 is the second end point of the reflecting surface 120; d is the vertical distance between the first total internal reflection surface 111 and the second total internal reflection surface 112; H is the vertical distance between the second end O2 of the reflecting surface 120 and the second total internal reflection surface 112; b is the included angle between the reflecting surface 120 and the second total internal reflection surface 112; a is half of the maximum incident angle, which is explained in Figure 2 ; and L is the distance between the end of the first total internal reflection surface 111 close to the reflecting surface 120 and the second end O2 of the reflecting surface 120 in the first direction. The first direction is the length direction of the light guide 110, i.e. L is the distance between the intersection point O3 of the first total internal reflection surface 111 and the light extinction surface 114 and the second end (O2 point) of the reflecting surface 120 in the first direction.

[0046] In the specific setting of the reflecting surface 120, L satisfies: ; and . In the above, k and l are redundancy amounts.

[0047] Continuing to refer to Figure 6 , when the light ray S5 enters into the light guide 110, the intersection point of the light ray S5 and the second total internal reflection surface 112 is O8. After entering into the light guide 110, the light ray S5 is reflected to the second end O2 of the reflecting surface 120, and then is reflected to the second total internal reflection surface 112 by the reflecting surface 120. Then, the light ray S5 is reflected to the reflecting surface 120 by the second total internal reflection surface 112 (the intersection point of the light ray S5 and the reflecting surface is O9), and then is reflected to the intersection point O3 of the first total internal reflection surface 111 and the light extinction surface 114 by the reflecting surface 120. To avoid the light ray S5 entering into the first total internal reflection surface 111 and the second total internal reflection surface 112, the reflecting surface 120 should satisfy that the light ray is located between O1 and O3, i.e. the light extinction surface 114 can absorb the light ray after the second reflection of the light ray S5.

[0048] For the convenience of understanding, some reference lines are introduced according to the mirror principle of light. The reflected light of the light ray S5 is mirrored with the reflecting surface 120 as the reference to obtain a corresponding virtual line. In addition, the second total internal reflection surface 112 is also mirrored with the reflecting surface 120 as the reference, and the reflecting surface 120, the second total internal reflection surface 112 and the mirrored surface thereof are extended to intersect, and the intersection point is O7. The intersection point of the mirrored light ray of the light ray S5 and the mirrored surface of the second total internal reflection surface 112 is O4. Two auxiliary reference lines L1 and L2 are constructed, wherein L1 is a vertical line segment (line segment O2O5, O5 is the intersection point of L1 and the second total internal reflection surface 112) from the second end point O2 of the reflecting surface 120 to the second total internal reflection surface 112, and the length thereof is H; L2 is a vertical line segment (line segment O4O6, O6 is the intersection point of L2 and the second total internal reflection surface 112) from the intersection point O4 to the second total internal reflection surface 112, and the length thereof is C. The length of the light ray S5 propagating in the light guide piece 110 to the second end O2 of the reflecting surface 120 is A (the length of the line segment O2O8); the length of the light ray S5 reflected by the reflecting surface 120 for the first time to the second total internal reflection surface 112 is B, that is, the length of the line segment O2O4 is B (according to the mirror principle). The length of the light ray S5 reflected by the reflecting surface 120 for the second time to O3 is D, that is, the line segment O3O9; then according to the reflection angle relationship of the light ray and the mirror relationship, the following formulas can be obtained: Formula 1; Formula 2; Formula 3; Formula 4; Formula 5; Bringing formula 1 and formula 2 into formula 3 can obtain:

[0049] Bringing formula 4 into formula 5 can obtain:

[0050] It can be known from the above description that when the light ray S5 is reflected for the second time to the intersection point O3 of the first total internal reflection surface 111 and the light extinction surface 114, the light ray S5 can enter the critical state between the first total internal reflection surface 111 and the second total internal reflection surface 112. The length of L is the length of L corresponding to the above-mentioned critical state obtained by calculation through the above-mentioned formulas. In order to eliminate the stray light of the second reflection, when L is set, it satisfies . Considering some processing errors, some redundancies are involved, so the obtained formula is: Wherein, l is the redundancy, exemplary, l can be between 0~0.3mm. For example, l can be 0.1, 0.2, 0.3, etc.

[0051] Reference Figure 7 In order to ensure that the light can be spread in the light guide 110, when the coupling-in light is obliquely incident into the light guide 110 at another angle, the light can be ensured to be spread in the whole light guide 110, when L is set, it satisfies: .

[0052] In Figure 7 , the reflecting surface 120 and the second total internal reflection surface 112 are extended to intersect, the intersection point is O7, and the included angle between the reflecting surface 120 and the second total internal reflection surface 112 is b. The incident angle of the light S6 when it is incident on the reflecting surface 120 is a (a Figure 6 and Figure 7 , the angles of the light S5 and S6 are both a, but the oblique directions are different), after being incident into the light guide 100, it is reflected to the second total internal reflection surface 112 (the intersection point is O10) by the reflecting surface 120. In addition, two perpendicular lines are introduced at the point O3 and the point O2, and the intersection points with the second total internal reflection surface 112 are O12 and O11 respectively. Then, along the first direction, L can be divided into two line segments O11O10 and O12O10. Wherein, the length of O11O10 is , and the length of O10O12 is ; Then, .

[0053] In order to ensure that the light can be incident into the first total internal reflection surface 111 and the second total internal reflection surface 112, L satisfies: .

[0054] Considering some processing errors, some redundancies are involved, so the formula obtained is: Wherein, k is the processing redundancy. Exemplarily, k can be between 0~0.3mm. For example, k can be 0.1, 0.2, 0.3, etc.

[0055] In another alternative scheme, considering the requirement of different maximum incident angles, when the light in all angles in the maximum incident angle does not need to satisfy the elimination of stray light and the spread of the light guide, the corresponding design satisfies the following conditions: ; ; Wherein, j is a coefficient, 50%≤j≤1. Exemplarily, j can be 50%, 60%, 70%, 80%, 90%, 1, etc. Other parameters can refer to Figure 6 andFigure 7 The related description in the above.

[0056] In another variant, on the basis of the above variant, the redundancy and the incident angle can be considered simultaneously. Then the corresponding formula can be transformed as: ; ; Wherein, j is a coefficient, 50%≤j≤1; k, l are redundancy. Other parameters can refer to the related description in the above. Figure 6 and Figure 7

[0057] As can be seen from the above different example schemes, by setting the reflecting surface 120, the light rays incident into the optical device within the incident angle (at least 50% of the maximum incident angle) can be fully spread and the stray light can be reduced, thereby improving the propagation effect of the light rays in the optical device and improving the display effect of the optical device when applied to the AR device or the VR device.

[0058] In a specific possible embodiment, when the light extinction surface 114 is specifically set, the light extinction surface 114 is set to be inclined relative to the first total internal reflection surface 111, and the light extinction surface 114 forms an obtuse angle with the first total internal reflection surface 111. That is, when the light extinction surface 114 is set, the light extinction surface 114 can be inclined relative to the first total internal reflection surface 111 and the reflecting surface 120, or perpendicular to one of the surfaces. When set in this way, a shorter length of the reflecting surface 120 can meet the light propagation requirement. Of course, it should be understood that even if a shorter length of the reflecting surface 120 is used, the length of the reflecting surface 120 should meet the requirement that all the light rays incident into the light guide 110 can irradiate to the reflecting surface 120 and be coupled by the reflecting surface 120.

[0059] In an optional scheme, when the connecting surface 113 is specifically set, the connecting surface 113 is set to be inclined relative to the second total internal reflection surface 112, and the connecting surface 113 forms an obtuse angle with the reflecting surface 120. That is, the connecting surface 113 is inclined to the outside of the light guide 110, so that when the light rays are incident into the light guide 110 at an inclined angle, the light rays can irradiate to the second end of the reflecting surface 120, thereby reducing the length of the reflecting surface 120.

[0060] In a specific possible embodiment, the optical device further comprises a polyhedral structure, the reflecting surface, the light extinction surface and the connecting surface are surfaces of the polyhedral structure, and the polyhedral structure is adhesively connected to the light guide to facilitate the preparation of the optical device. In a specific adhesion, different ways can be used to realize. For example, Figure 8 and Figure 9 ​As shown in FIG. 1, the reflecting surface 120, the light extinction surface 114 and the connecting surface 113 are prepared on the polyhedral structure 140 made of the same material as the light guide 110. According to the embodiment shown in FIG. 1, the light guide 110 and the polyhedral structure 140 are prepared by using the same material, the first total internal reflection surface 111 and the second total internal reflection surface 112 are prepared on the light guide 110, and the reflecting surface 120, the light extinction surface 114 and the connecting surface 113 are prepared on the polyhedral structure 140. In the process of forming the optical device, the light guide 110 and the polyhedral structure 140 are bonded and fixed, so that the reflecting surface 120, the light extinction surface 114 and the connecting surface 113 are connected with the first total internal reflection surface 111 and the second total internal reflection surface 112, respectively. Similarly, as shown by the dashed line in FIG. 2, Figure 8 As shown by the dashed line in FIG. 1, Figure 9 As shown by the dashed line in FIG. 2, Figure 9 Another division mode of the light guide 110 and the polyhedral structure 140 is shown in FIG. 3, which has the same principle as that shown in FIG. 1, and thus will not be described herein. Figure 8 As shown by the dashed line in FIG. 3,

[0061] Of course, in addition to the above-mentioned modes, the reflecting surface 120, the light extinction surface 114 and the connecting surface 113 can also be arranged in other modes, which will not be described herein.

[0062] The embodiment of the present application further provides a near-eye display device, which comprises a light ray generator and the optical device according to any one of the above-mentioned embodiments; wherein, The light rays generated by the light ray generator are incident into the light guide 110 only at the light ray incident end.

[0063] In the above-mentioned technical solution, the reflecting surface 120 is arranged to be inclined relative to the first total internal reflection surface 111, so that the light rays incident into the light guide 110 can be reflected to propagate between the first total internal reflection surface 111 and the second total internal reflection surface 112. Meanwhile, the first end and the second end of the reflecting surface 120 are arranged to make the reflected light rays spread in the light guide 110, so as to realize uniform arrangement of the light rays. In addition, the stray light reflected by the reflecting surface 120 can be filtered, so as to improve the optical performance of the optical device and the effect of the light guide 110 in the process of displaying and realizing near-eye display.

[0064] One or more embodiments of the present disclosure are intended to cover all such alternatives, modifications, and variations as fall within the broad scope of the appended claims. Accordingly, any one or more of the above-described embodiments of the disclosure can be combined with any other embodiment(s), and the application will also cover any alternatives, modifications, equivalents, improvements and / or furnishing caused to result from any combination of the elements of the application with those of the prior art.

[0065] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An optical device, characterized by The optical device comprises: a light guide and a reflecting surface; the light guide comprises first and second mutually parallel total internal reflection surfaces, the second total internal reflection surface having opposite light incident and exit ends; the reflecting surface is arranged obliquely to the first total internal reflection surface and is close to the light incident end; a first end of the reflecting surface is located on a side of the first total internal reflection surface away from the second total internal reflection surface, a second end of the reflecting surface is located between the first and second total internal reflection surfaces, and a distance between the second end of the reflecting surface and the second total internal reflection surface is set; a light-absorbing surface is further arranged between the first total internal reflection surface and the reflecting surface.

2. The optical device of claim 1, wherein, the first and second ends of the reflecting surface satisfy: light rays within an incident angle of at least 50% of a maximum incident angle enter the optical device through the light incident end, are reflected once by the reflecting surface to the second total internal reflection surface, and spread over the light guide to achieve total internal reflection propagation; edge light rays obliquely incident to the second end of the reflecting surface are reflected twice by the reflecting surface and are reflected to a space between the first end of the reflecting surface and the first total internal reflection surface.

3. The optical device of claim 2, wherein, one end of the light-absorbing surface is connected to the first end of the reflecting surface, and the other end is fixedly connected to an end of the first total internal reflection surface close to the reflecting surface and is used to absorb light rays reflected twice by the reflecting surface.

4. The optical device of claim 3, wherein, the light-absorbing surface is a black light-absorbing surface or a rough surface; when the light-absorbing surface is a rough surface, the roughness of the rough surface is greater than the roughness of the reflecting surface.

5. The optical device of claim 3, wherein, the light-absorbing surface is arranged obliquely to the first total internal reflection surface and forms an obtuse angle with the first total internal reflection surface.

6. The optical device of claim 3, wherein, a connecting surface is further arranged, one end of the connecting surface is connected to the second end of the reflecting surface, and the other end is connected to an end of the second total internal reflection surface close to the second end of the reflecting surface.

7. The optical device of claim 6, wherein, the reflecting surface, the light-absorbing surface, and the connecting surface are surfaces of a polyhedral structure; the polyhedral structure is adhesively connected to the light guide.

8. The optical device according to any one of claims 2 to 7, characterized in that a length direction of the first total internal reflection surface is a first direction; a distance L between an end point of the first total internal reflection surface close to the reflecting surface and the second end of the reflecting surface in the first direction satisfies: ; and ; wherein, H is a vertical distance between the second end of the reflecting surface and the second total internal reflection surface; b is an included angle between the reflecting surface and the second total internal reflection surface; a is an angle of one-half of the maximum incident angle; d is a vertical distance between the first and second total internal reflection surfaces; k and l are redundancy amounts.

9. The optical device according to any one of claims 2 to 7, characterized in that, a length direction of the first total internal reflection surface is a first direction; a distance L between an end point of the first total internal reflection surface close to the reflecting surface and the second end of the reflecting surface in the first direction satisfies: ； ； H is a vertical distance between the second end of the reflecting surface and the second total internal reflection surface; b is an included angle between the reflecting surface and the second total internal reflection surface; a is an angle of one-half of the maximum incident angle; d is the vertical distance between the first total internal reflection surface and the second total internal reflection surface; j is a coefficient, and 50%≤j≤1.

10. The optical device according to any one of claims 2 to 7, characterized in that, The length direction of the first total internal reflection surface is the first direction; The distance L between the end point of the first total internal reflection surface close to the reflecting surface and the second end of the reflecting surface in the first direction satisfies: ； ； H is the vertical distance between the second end of the reflecting surface and the second total internal reflection surface; b is the included angle between the reflecting surface and the second total internal reflection surface; a is the angle of one half of the maximum incident angle; d is the vertical distance between the first total internal reflection surface and the second total internal reflection surface; j is a coefficient, and 50%≤j≤1. k, l are redundancy amounts.

11. A near-eye display device, comprising: The optical device comprises a light ray generator and an optical device according to any one of claims 1-10; wherein, The light ray generated by the light ray generator is incident into the light guide only at the light ray incident end.

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