Optical device and near-eye display device

Abstract

The application provides an optical device and a near-eye display device. The optical device comprises a light guide and a reflecting surface. The reflecting surface is arranged obliquely relative to two parallel total internal reflection surfaces of the light guide to couple light into the light guide. First and second ends of the reflecting surface are arranged on opposite sides of the first total internal reflection surface. The first and second ends of the reflecting surface satisfy the following conditions: light within an incident angle range enters the optical device through the light incident end, is reflected by the reflecting surface once to the second total internal reflection surface, and spreads in the light guide; and edge light within the incident angle range that is incident obliquely to the second end of the reflecting surface is reflected by the reflecting surface twice and then reflected to a space between the first end of the reflecting surface and the first total internal reflection surface. By arranging the reflecting surface obliquely relative to the first total internal reflection surface, at least 50% of light within a maximum incident angle range is spread in the light guide and stray light is filtered, thereby improving the effect of the light guide in display implementation of the near-eye display.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical technology, in particular to an optical device and a near-eye display device. BACKGROUND

[0002] 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 displayed 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

[0003] The present application provides an optical device and a near-eye display device, which improves the propagation effect of light in the optical device and further improves the display effect.

[0004] The present application provides an optical device, which comprises a light guide and a reflecting surface, wherein,

[0005] The light guide comprises a first total internal reflection surface and a second total internal reflection surface which are parallel to each other; the second total internal reflection surface has opposite light incident ends and exit ends;

[0006] The reflecting surface is inclined to the first total internal reflection surface and is close to the light incident end;

[0007] 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 certain distance;

[0008] The first end and the second end of the reflecting surface satisfy:

[0009] The light rays within the incident angle, which 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 on the light guide to realize total internal reflection propagation; wherein the incident angle is at least 50% of the maximum incident angle;

[0010] The edge light rays, which are inclined to the second end of the reflecting surface, are reflected twice by the reflecting surface and are reflected between the first end of the reflecting surface and the first total internal reflection surface.

[0011] In the technical scheme, 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, and the light reflected by the mirror can be spread in the light guide member, so that the light is uniformly arranged, and the stray light reflected twice by the mirror is filtered, so that the optical performance of the optical device is improved, and the effect of the light guide member in the display for near-eye display is improved.

[0012] In one specific implementation, the light-absorbing surface is connected at one end to the first end of the mirror and at the other end to the first total internal reflection surface near the end of the mirror.

[0013] In one specific implementation, the light-absorbing surface is a black light-absorbing surface or a rough surface.

[0014] In the case of a rough surface, the roughness of the rough surface is greater than the roughness of the mirror.

[0015] In one specific implementation, the light-absorbing surface is arranged obliquely relative to the first total internal reflection surface, and the light-absorbing surface forms an obtuse angle with the first total internal reflection surface.

[0016] In one specific implementation, the light-absorbing surface is connected at one end to the first end of the mirror and at the other end to the first total internal reflection surface near the end of the mirror.

[0017] In one specific implementation, the light-absorbing surface is a black light-absorbing surface or a rough surface.

[0018] The polyhedron is bonded to the light guide member.

[0019] In one specific implementation, the length direction of the first total internal reflection surface is the first direction.

[0020] The distance L between the end point of the first total internal reflection surface near the mirror and the second end of the mirror in the first direction satisfies:

[0021] L>(H+d)*tan(2b+a)-k; and

[0022] wherein,

[0023] H is the vertical distance between the second end of the mirror and the second total internal reflection surface.

[0024] b is the included angle between the reflecting surface and the second total internal reflection surface;

[0025] a is the angle of half of the maximum incident angle;

[0026] d is the vertical distance between the first total internal reflection surface and the second total internal reflection surface;

[0027] k, l are redundancy amounts.

[0028] In one specific implementation, the length direction of the first total internal reflection surface is the first direction;

[0029] The distance L between the end point of the reflecting surface close to the first total internal reflection surface and the second end of the reflecting surface in the first direction satisfies:

[0030] L > (H + d) * tan(2b + ja);

[0031]

[0032] H is the vertical distance between the second end of the reflecting surface and the second total internal reflection surface;

[0033] b is the included angle between the reflecting surface and the second total internal reflection surface;

[0034] a is the angle of half of the maximum incident angle;

[0035] d is the vertical distance between the first total internal reflection surface and the second total internal reflection surface;

[0036] j is a coefficient, and 50%≤j≤1.

[0037] In one specific implementation, the length direction of the first total internal reflection surface is the first direction;

[0038] The distance L between the end point of the reflecting surface close to the first total internal reflection surface and the second end of the reflecting surface in the first direction satisfies:

[0039] L > (H + d) * tan(2b + ja) - k;

[0040]

[0041] H is the vertical distance between the second end of the reflecting surface and the second total internal reflection surface;

[0042] b is the included angle between the reflecting surface and the second total internal reflection surface;

[0043] a is the angle of half of the maximum incident angle;

[0044] d is a vertical distance between the first total internal reflection surface and the second total internal reflection surface;

[0045] j is a coefficient, and 50%≤j≤1;

[0046] k, l are redundancy amounts.

[0047] In a second aspect, a near-eye display device is provided, comprising a light ray generator, and the optical device according to any one of the preceding aspects; wherein,

[0048] The light ray generated by the light ray generator is incident into the light guide only at the light ray incidence end.

[0049] In the above technical solution, by adopting the reflection mirror which is arranged obliquely relative to the first total internal reflection surface, the light ray incident into the light guide can be reflected to propagate between the first total internal reflection surface and the second total internal reflection surface. Meanwhile, by adopting the first end and the second end of the reflection mirror, the reflected light ray can be spread in the light guide, so that the uniform arrangement of the light ray is realized. In addition, the stray light reflected by the reflection mirror can be filtered, so that the optical performance of the optical device is improved, and the effect of the light guide in the display of the near-eye display is improved. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 An application scenario of the optical device provided by the embodiment of the present application is shown in the figure;

[0051] Figure 2 An incidence angle of the optical device provided by the embodiment of the present application is shown in the figure;

[0052] Figure 3 A structure of the optical device provided by the embodiment of the present application is shown in the figure;

[0053] Figure 4 A propagation of the light ray in the optical device provided by the embodiment of the present application is shown in the figure;

[0054] Figure 5 Another propagation of the light ray in the optical device provided by the embodiment of the present application is shown in the figure;

[0055] Figure 6 Another propagation of the light ray in the optical device provided by the embodiment of the present application is shown in the figure;

[0056] Figure 7 Another propagation of the light ray in the optical device provided by the embodiment of the present application is shown in the figure;

[0057] Figure 8 A specific structure of the optical device provided by the embodiment of the present application is shown in the figure;

[0058] Figure 9Another specific structural diagram of the optical device provided by the embodiment of the present application is shown. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings.

[0060] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in one or more embodiments of the present application should be understood as the general meaning understood by a person skilled in the art to which the present disclosure belongs. The terms "first", "second" and the like used in one or more embodiments of the present application do not represent any order, number or importance, but are only used to distinguish different components. The terms "include" or "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 position of the described object changes, the relative positional relationship may also change accordingly.

[0061] In order to facilitate the understanding of the optical device provided by the embodiment of the present application, the application scenario thereof is first described. The optical device provided by the embodiment of the present application is applied in an AR (Augmented Reality, augmented reality technology) or VR (Virtual Reality, virtual reality technology) device. The current optical waveguide is prone to uneven light propagation, which affects the display effect of the AR or VR device. Therefore, the optical device provided by the embodiment of the present application is used 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 specific drawings.

[0062] Reference Figure 1 , Figure 1 The application scenario of the optical device provided by the embodiment of the present application is shown. When the optical scene provided by the embodiment of the present application is applied, the light generated by the light generator 200 enters the light guide 110 in the optical device 100, and the light is coupled into the two total internal reflection surfaces of the light guide 110 through the reflecting surface 120 of the optical device 100 to propagate the light through total internal reflection, and the light is coupled out of the light guide 110 through the coupling-out component 130 in the light guide 110 to propagate to the user's eyes. The light generated by the light generator 200 can be a collimated image. The light generator 200 can be an optical collimating device, or can also be a light source generator component with scanning properties, which is not specifically limited in the embodiment of the present application.

[0063] For the convenience of describing the optical device 100 provided by the embodiments of the present application, first define the maximum incident angle. When the light generator 200 emits to the optical device 100, the maximum angle of the light generator 200 incident to the optical device 100 is defined as the maximum incident angle. As shown in the reference light ray in Figure 2 , the edge light ray emitted by the light generator 200 forms the maximum incident angle incident to the optical device 100, that is, the maximum incident angle is determined by the edge light ray of the light generator 200 (as shown in the angle α in Figure 2 , the angle α is the included angle formed by the two edge light rays. In addition, the incident angle is also shown in Figure 2 , as shown by the dotted line in Figure 2 , the incident angle β, wherein β≤α. In Figure 2 , the half angle a of the maximum incident angle is also shown, a = 1 / 2α, that is, the angle obtained after the maximum incident angle is divided by the angle bisector.

[0064] Referring to Figure 3 , Figure 3 , a structure diagram of the optical device provided by the embodiments of the present application is shown. The main structure of the optical device provided by the embodiments of the present application includes a light guide member 110 and a reflecting surface 120. The light guide member 110 has a first total internal reflection surface 111 and a second total internal reflection surface 112 which are parallel to each other. In combination with the description shown in Figure 1 , the second total internal reflection surface 112 is located on the side close to the light generator 200, and 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 the light propagates in the light guide member 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 the light.

[0065] When the light is incident, the light guide member 110 has opposite light incident ends and exit ends (not labeled in Figure 3 , refer to the positions of the light incident and light exit in Figure 1 ). When the light incident ends and exit ends are specifically arranged, the light incident ends and exit ends are arranged along the length direction of the light guide member 110 and are located at the two opposite ends of the second total internal reflection surface 112. The light incident to the light guide member 110 from the light incident end can be coupled into the first total internal reflection surface 111 and the second total internal reflection surface 112 for total internal reflection by the reflecting surface 120.

[0066] In the specific formation of the reflecting surface 120, the reflecting surface 120 can be formed by directly coating a reflecting layer on the light guide 110, or attaching a reflecting layer on the light guide 110 as the reflecting surface 120. In the embodiments of the present application, no specific limitation is made, as long as the light can be coupled into the space between the first total internal reflection surface 111 and the second total internal reflection surface 112.

[0067] In the specific setting of the reflecting surface 120, the reflecting surface 120 is set to be inclined relative to the length direction of the light guide 110, i.e. the reflecting surface 120 is set to be inclined relative to the first total internal reflection surface 111. In addition, since the reflecting surface 120 serves as a coupling-in device, the reflecting surface 120 is set close to the light incident end, so as to ensure that the light can be reflected by the reflecting surface 120 to the space between the first total internal reflection surface 111 and the second total internal reflection surface 112, so as to realize the coupling-in of the light.

[0068] When the reflecting surface 120 is inclined relative to the first total internal reflection surface 111, the reflecting surface 120 has a first end O1 and a second end O2 opposite to each other, wherein the first end O1 is a high end, and the second end O2 is a low end. Specifically, the reflecting surface 120 has an intersection with the extension line of the first total internal reflection surface 111 (as shown by the dashed line in FIG. 1), and the first end O1 and the second end O2 of the reflecting surface 120 are arranged on opposite sides of the extension line of the first total internal reflection surface 111. Among them, the first end O1 of the reflecting surface 120 is located on the side of the first total internal reflection surface 111 away from the second total internal reflection surface 112, which can also be understood as that the first end O1 protrudes outwardly from the first total internal reflection surface 111. The second end O2 of the reflecting surface 120 as the low end is located between the first total internal reflection surface 111 and the second total internal reflection surface 112, and there is a certain distance between the second end O2 of the reflecting surface 120 and the second total internal reflection surface 112, i.e. the second end O2 of the reflecting surface 120 does not intersect with the second total internal reflection surface 112. Figure 3 With the placement direction of the light guide 110 in FIG. 1 as the reference direction, the first end O1 and the second end O2 of the reflecting surface 120 are arranged in a left-high and right-low manner, so that the reflecting direction of the reflecting surface 120 is towards the inside of the light guide 110, and the light reflected by the reflecting surface 120 can enter into the light guide 110. Figure 3

[0069] ​In addition, the optical device further comprises two exposed surfaces for connecting the reflecting surface 120 and the two total internal reflection surfaces (the first total internal reflection surface 111 and the second total internal reflection surface 112). For example, one of the exposed surfaces is a light-absorbing surface 114, which is located between the first total internal reflection surface 111 and the reflecting surface 120 and is used to connect the first total internal reflection surface 111 and the reflecting surface 120. For example, one end of the light-absorbing 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 reflection surface 111 close to the first end O1 of the reflecting surface 120 and is used to absorb the light reflected between the first end O1 of the reflecting surface 120 and the first total internal reflection surface 111 after being reflected twice by the reflecting surface 120, i.e., to absorb the light reflected twice by the reflecting surface 120. The light reflected twice by the reflecting surface 120 is stray light in the light guide 110.

[0070] The light-absorbing surface 114 described above can be used in different ways to absorb the light reflected between the first total internal reflection surface 111 and the reflecting surface 120 by the reflecting surface 120. For example, the light-absorbing surface 114 is a black light-absorbing surface or a rough surface. When the light-absorbing surface 114 is a black light-absorbing surface, the light-absorbing performance of the black color can be used to absorb the light, thereby reducing the reflection of the light. When the light-absorbing surface 114 is a rough surface, the roughness of the rough surface is greater than the roughness of the reflecting 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 absorption in the present 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 the light or diffuse reflection, transmission, etc.

[0071] The other exposed surface is located between the second total internal reflection surface 112 and the reflecting surface 120 and is used as a connecting surface 113 to connect the second total internal reflection surface 112 and the reflecting surface 120. For example, one end of the connecting surface 113 is connected to the second end O2 of the reflecting 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 reflecting surface 120. The connecting surface 113 can also be a light-absorbing surface, thereby reducing the reflection of the light irradiated thereon to reduce the 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-absorbing surface, the description of the light-absorbing surface in the foregoing can be referred to, and will not be described here again.

[0072] It should be understood that when connecting the first total internal reflective surface 111, the second total internal reflective surface 112, and the reflective surface 120, the connection is not limited to the two exposed surfaces in the example above. Other exposed surfaces can also be used to connect the first total internal reflective surface 111, the second total internal reflective surface 112, and the reflective surface 120. For example, the first total internal reflective surface 111 and the reflective surface 120 can be connected by two or three exposed surfaces; the second total internal reflective surface 112 and the reflective surface 120 can be connected by two or three exposed surfaces. For ease of description, in this embodiment, the connection between the first total internal reflective surface 111, the second total internal reflective surface 112, and the reflective surface 120 in the example above, via an extinction surface 114 and a connecting surface 113, will be used for illustration.

[0073] For ease of description, the intersection of the matting surface 114 and the first total internal reflection surface 111 is defined as point O3, and the intersection of the reflecting surface 120 and the connecting surface 113 is defined as point O2.

[0074] 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 through the reflecting surface 120 to the space between the first total internal reflection surface 111 and the second total internal reflection surface 112, the light rays completely cover the light guide 110.

[0075] 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.

[0076] 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.

[0077] Firstly, the first edge light S1 is incident to the reflecting surface 120 near the second end O2, and after being reflected by the reflecting surface 120, the first edge light S1 is reflected to the intersection point (O3 point) of the first total internal reflection surface 111 and the light extinction surface 114 by the second total internal reflection surface 112. At this time, the O3 point as the end point of the first total internal reflection surface 111 has the total internal reflection property, and the first edge light S1 is reflected to the second total internal reflection surface 112 by the first total internal reflection surface 111 at the O3 point, and propagates between the first total internal reflection surface 111 and the second total internal reflection surface 112 in the total internal reflection manner.

[0078] The second edge light S2 is incident to the reflecting surface 120 near the first end O1, and after being reflected by the reflecting surface 120, the second edge light S2 is reflected to the intersection point (O3 point) 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 the total internal reflection manner.

[0079] 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 O3 point, 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, it is substantially illuminated by the coupled light on the entire second total internal reflection surface 112. 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.

[0080] When the optical device propagates the light, on the one hand, the uniformity of the light propagating is required to be met, and on the other hand, the stray light needs to be eliminated to improve the effect of the light guide 110 propagating the light. The stray light refers to the light that does not meet the total internal reflection requirement when the light propagates between the first total internal reflection surface 111 and the second total internal reflection surface 112. It is shown in Figure 5 Figure 5 ​The example illustrates two different light rays, S3 and S4, where S3 is stray light. During propagation, ray S3 is a ray that, after being reflected twice by reflective surface 120, enters the space between the first total internal reflecting surface 111 and the second total internal reflecting surface 112. That is, ray S3 is reflected by reflective surface 120 to the second total internal reflecting surface 112, then reflected again by the second total internal reflecting surface 112 to reflective surface 120, and finally reflected by reflective surface 120 into the space between the first and second total internal reflecting surfaces 111 and 112. Ray S4 is a ray that, after being reflected once by reflective surface 120, enters the space between the first and second total internal reflecting surfaces 111 and 112. Comparing rays S3 and S4, it can be seen that stray light is generated because the light is reflected more than 120 times by the reflecting surface 120, so that when it enters between the first total internal reflecting surface 111 and the second total internal reflecting surface 112, it does not meet the requirements of the total internal reflection angle (refer to rays S3 and S4). This kind of light is called stray light.

[0081] 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 A similar situation where the surface reflects the object 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 reflection 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.

[0082] 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.

[0083] It can be seen from the above description that the optical device provided by the embodiment of the application can reflect the light incident into the light guide member 110 to the first total internal reflection surface 111 and the second total internal reflection surface 112 for propagation by tilting the reflection surface 120 relative to the first total internal reflection surface 111. In addition, in consideration of the propagation effect of the light in the optical device, the first end O1 and the second end O2 of the reflection surface 120 are arranged so that the reflected light can be spread in the light guide member 110, thereby achieving uniform arrangement of the light, and in addition, stray light reflected by the reflection surface 120 can be filtered, thereby improving the optical performance of the optical device and improving the effect of the light guide member 110 in the display for near-eye display.

[0084] In the specific arrangement of the first end O1 and the second end O2 of the reflection surface 120, it is specifically related to the thickness of the light guide member 110, the inclination angle of the reflection surface 120, the intersection point of the first total internal reflection surface 111 and the light extinction surface 114, and other parameters.

[0085] Reference Figure 6 Some parameters related to the reflection surface 120 are defined in Figure 6 First, the parameters in Figure 6 are described. Among them, the point O2 is the second end point of the reflection 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 reflection surface 120 and the second total internal reflection surface 112; b is the included angle between the reflection surface 120 and the second total internal reflection surface 112; a is half of the maximum incident angle, which is described with reference to the related description in Figure 2 ; L is the distance between the end point of the first total internal reflection surface 111 close to the reflection surface 120 and the second end O2 of the reflection surface 120 in the first direction. Among them, the first direction is the length direction of the light guide member 110, that is, 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 (point O2) of the reflection surface 120 in the first direction.

[0086] In the specific arrangement of the reflection surface 120, L satisfies:

[0087] L>(H+d)*tan(2b+a)-k; and Wherein, k, l are redundancy.

[0088] Continue 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, the light ray S5 is reflected by the second end O2 of the reflection surface 120 after entering into the light guide 110, is reflected by the reflection surface 120 to the second total internal reflection surface 112, is reflected by the second total internal reflection surface 112 to the reflection surface 120 (the intersection point of the light ray S5 and the reflection surface 120 is O9), and is reflected by the reflection surface 120 to the intersection point O3 of the first total internal reflection surface 111 and the light extinction surface 114. In order to avoid the light ray S5 entering into the first total internal reflection surface 111 and the second total internal reflection surface 112, the reflection surface 120 should be arranged to satisfy that the light ray is between O1 and O3, that is, the light extinction surface 114 can absorb the light ray S5 after being reflected twice.

[0089] For the convenience of understanding, some reference lines are introduced according to the mirror image principle of the light ray. The reflected light ray of the light ray S5 is mirrored with the reflection 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 reflection surface 120 as the reference, and the reflection surface 120, the second total internal reflection surface 112 and the mirrored surface 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 reflection surface 120 to the second total internal reflection surface 112, and the length of L1 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 of L2 is C. The length of the light ray S5 propagating in the light guide 110 to the second end O2 of the reflection surface 120 is A (the length of the line segment O2O8); the length of the light ray S5 reflected by the reflection surface 120 to the second total internal reflection surface 112 for the first time is B, that is, the length of the line segment O2O4 is B (according to the mirror image principle). The length of the light ray S5 reflected by the reflection surface 120 to O3 for the second time is D, that is, the length of the line segment O3O9; and the following formula can be obtained according to the reflection angle relationship of the light ray and the mirror image relationship:

[0090]

[0091]

[0092] C=(A+B)*cos a, formula 3;

[0093]

[0094] L=D-B*sina, formula 5;

[0095] The formula 1 and the formula 2 are brought into the formula 3 to obtain:

[0096]

[0097] Substitute equation 4 into equation 5, we get:

[0098]

[0099] From the above description, it is known that when the light ray S5 is twice reflected to the intersection point O3 of the first total internal reflection surface 111 and the light extinction surface 114, the twice reflected light ray S5 is in a critical state of entering between the first total internal reflection surface 111 and the second total internal reflection surface 112. The length of L is the length calculated by the above equation, which is the length of L corresponding to the above critical state. In order to eliminate the stray light of twice reflection, when L is set, it satisfies: Considering some processing errors, some redundancies are involved, so the obtained equation is: Wherein, l is the redundancy, and the exemplary l can be between 0-0.3mm. For example, l can be 0.1, 0.2, 0.3, etc.

[0100] Reference Figure 7 In order to ensure that the light ray can fill the entire light guide 110 when the coupling-in light ray is obliquely incident into the light guide 110 at another angle, when L is set, it satisfies: L>(H+d)*tan(2b+a)-k.

[0101] In Figure 7 , the intersection point of the reflection surface 120 and the second total internal reflection surface 112 is O7, and the angle between the reflection surface 120 and the second total internal reflection surface 112 is b. The incident angle of the light ray S6 when it is incident on the reflection surface 120 is a. Figure 6 And Figure 7 In the above, although the angles of the light rays S5 and S6 are both a, the inclination directions of the two are different, and after being incident into the light guide 100, the light ray S6 is reflected by the reflection surface 120 to the second total internal reflection surface 112 (the intersection point is O10). In addition, two perpendicular lines are introduced at the points O3 and 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. Among them,

[0102] The length of O11O10 is H*tan(2b+a), and the length of O10O12 is d*tan(2b+a);

[0103] Therefore, L=(H+d)*tan(2b+a).

[0104] To ensure that light can be injected into the first total internal reflection surface 111 and the second total internal reflection surface 112, L satisfies: L > (H + d) * tan (2b + a).

[0105] Considering some processing errors, some redundancies are involved, so the formula obtained is: L > (H + d) * tan (2b + a) - k. 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.

[0106] In another alternative, considering the requirement of different maximum incident angles, without the need for light in all angles within the maximum incident angle to satisfy the elimination of stray light and the full coverage of the light guide, the corresponding design satisfies the following conditions:

[0107] L > (H + d) * tan (2b + ja);

[0108]

[0109] Wherein, j is a coefficient, 50%≤j≤1. Exemplarily, j can be 50%, 60%, 70%, 80%, 90%, 1, etc. Other parameters can refer to the related descriptions in Figure 6 and Figure 7 .

[0110] In another variant, on the basis of the above variant, redundancy and incident angle can be considered at the same time. The corresponding formula can be transformed as:

[0111] L > (H + d) * tan (2b + ja) - k;

[0112]

[0113] Wherein, j is a coefficient, 50%≤j≤1; k, l are redundancy. Other parameters can refer to the related descriptions in Figure 6 and Figure 7 .

[0114] As can be seen from the above different example schemes, by arranging the reflection surface 120, the light injected into the optical device within the incident angle (at least 50% of the maximum incident angle) can be fully covered and the stray light can be reduced, thereby improving the propagation effect of the light in the optical device and improving the display effect of the optical device when applied to AR devices or VR devices.

[0115] In a specific possible embodiment, when the light extinction surface 114 is arranged, the light extinction surface 114 is arranged to be inclined to the first total internal reflection surface 111, and the light extinction surface 114 is arranged to be at an obtuse angle to the first total internal reflection surface 111. That is, when the light extinction surface 114 is arranged, the light extinction surface 114 can be arranged to be inclined to both the first total internal reflection surface 111 and the reflection surface 120, or perpendicular to one of the surfaces. When arranged in this way, a shorter length of the reflection surface 120 can be used to meet the requirements of the light propagation. Of course, it should be understood that even if a shorter length of the reflection surface 120 is used, the length of the reflection surface 120 should be sufficient to allow all the light incident on the light guide 110 to be able to irradiate the reflection surface 120 and be coupled by the reflection surface 120.

[0116] In an alternative arrangement, when the connecting surface 113 is arranged, the connecting surface 113 is arranged to be inclined to the second total internal reflection surface 112, and the connecting surface 113 is arranged to be at an obtuse angle to the reflection surface 120. That is, the connecting surface 113 is arranged to be inclined outwardly from the light guide 110, so that light incident on the light guide 110 at an inclined angle can irradiate the second end of the reflection surface 120, thereby reducing the length of the reflection surface 120.

[0117] In a specific possible embodiment, the optical device further comprises a polyhedral structure, the reflection surface, the light extinction surface and the connecting surface are surfaces of the polyhedral structure, and the polyhedral structure is bonded to the light guide to facilitate the preparation of the optical device. In a specific bonding process, different methods can be used. For example, Figure 8 and Figure 9 The reflection surface 120, the light extinction surface 114 and the connecting surface 113 are prepared on a polyhedral structure 140 made of the same material as the light guide 110, as shown by the dashed line in Figure 8 The entire optical device is divided into the light guide 110 and the polyhedral structure 140. The light guide 110 and the polyhedral structure 140 are prepared from 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 reflection surface 120, the light extinction surface 114 and the connecting surface 113 are prepared on the polyhedral structure 140. When the optical device is formed, the light guide 110 and the polyhedral structure 140 are bonded and fixed, so that the reflection surface 120, the light extinction surface 114 and the connecting surface 113 are connected to the first total internal reflection surface 111 and the second total internal reflection surface 112, respectively. Similarly, referring to the dashed line in Figure 9 , Figure 9 Another way of dividing the light guide 110 and the polyhedral structure 140 is shown in Figure 8 , which has the same principle as that shown in

[0118] Of course, in addition to the above, other ways can also be used to set the reflecting surface 120, the light extinction surface 114 and the connecting surface 113, which will not be described one by one here.

[0119] The embodiment of the present application also provides a near-eye display device, which comprises a light generator and the optical device of any one of the above.

[0120] The light generated by the light generator is incident into the light guide 110 only at the light incident end.

[0121] In the above technical solution, by setting the reflecting surface 120 to be inclined relative to the first total internal reflection surface 111, the light 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, by setting the first end and the second end of the reflecting surface 120, the reflected light can be spread in the light guide 110, so that the uniform arrangement of the light is realized, in addition, the stray light reflected by the reflecting surface 120 can be filtered, so that the optical performance of the optical device is improved, and the effect of the light guide 110 in the display implementation of the near-eye display is improved.

[0122] One or more embodiments of the present specification are intended to cover all such alternatives, modifications and variations falling within the broad scope of the appended claims. Therefore, any omission, modification, equivalent replacement, improvement, etc. made in the spirit and principle of one or more embodiments of the present specification should be included in the protection scope of the present disclosure.

[0123] The above is only a specific implementation manner 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 changes or replacements within the technical range disclosed by the present application, which should be included 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 application relates to an optical device, which 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 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 and second total internal reflection surfaces, and a set distance is provided between the second end of the reflecting surface and the second total internal reflection surface. The first and second ends of the reflecting surface satisfy the following conditions: Light rays within an incident angle of at least 50% of the 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 realize total internal reflection propagation. Edge light rays obliquely incident on the second end of the reflecting surface are reflected twice by the reflecting surface and are reflected between the first end of the reflecting surface and the first total internal reflection surface. The optical device further comprises an extinction surface, one end of the extinction surface is connected to the first end of the reflecting surface, the other end of the extinction surface is fixedly connected to one end of the first total internal reflection surface close to the reflecting surface, and the extinction surface is used for absorbing light rays reflected twice by the reflecting surface.

2. The optical device of claim 1, wherein, The extinction surface is a black light-absorbing surface or a rough surface.

3. The optical device of claim 2, wherein, When the extinction surface is a rough surface, the roughness of the rough surface is greater than the roughness of the reflecting surface. The extinction surface is arranged obliquely relative to the first total internal reflection surface, and the extinction surface forms an obtuse angle with the first total internal reflection surface.

4. The optical device of claim 2, wherein, The optical device further comprises a connecting surface, one end of the connecting surface is connected to the second end of the reflecting surface, and the other end of the connecting surface is connected to one end of the second total internal reflection surface close to the second end of the reflecting surface.

5. The optical device of claim 2, wherein, The reflecting surface, the extinction surface and the connecting surface are surfaces of a polyhedral structure.

6. The optical device of claim 5, wherein, The polyhedral structure is adhesively connected to the light guide. The length direction of the first total internal reflection surface is the first direction.

7. The optical device according to any one of claims 1 to 6, characterized in that 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 the following condition: H is the vertical distance between the second end of the reflecting surface and the second total internal reflection surface; L > (H + d) * tan(2b + a) - k; and wherein, b is the 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; k and l are redundancy amounts. The length direction of the first total internal reflection surface is the first direction.

8. The optical device according to any one of claims 1 to 6, characterized in that 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 the following condition: L > (H + d) * tan (2b + ja); 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 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.

9. The optical device according to any one of claims 1 to 6, 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 reflection surface close to the first total internal reflection surface and the second end of the reflection surface in the first direction satisfies: L>(H+d)*tan(2b+ja)-k; 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.

10. A near-eye display device, comprising: The optical device comprises a light ray generator and an optical device according to any one of claims 1-9; wherein, The light ray generator generates light rays, and only the light ray incident end of the light rays is incident into the light guide.

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