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 first end and the second end of the reflecting surface meet the following conditions: light in an incident angle enters the optical device through the light incident end, is reflected to the second total internal reflecting surface once through the reflecting surface, and overlays the light guide piece; and the edge light which is obliquely incident to the second end of the reflecting surface in the incident angle is reflected twice by the reflecting surface and then is reflected between the first end of the reflecting surface and the first total internal reflecting surface. The reflecting surface is inclined to the first total internal reflecting surface, the light within at least 50% of the maximum incident angle is spread in the light guide part, and stray light is filtered, so that the effect of the light guide part during near-to-eye display is improved.

Description

Technical Field

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

[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 systems, users have higher and higher technical requirements for products. Especially in the display process, the quality requirements for displayed images are also getting higher and higher. However, in the current near-eye display system, when the light is transmitted through the light guide, there is still the problem of uneven light transmission and stray light. Summary of the invention

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

[0004] The present application provides an optical device, which includes: a light guide and a reflective 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 a light incident end and a light emitting end which are opposite to each other;

[0006] The reflection surface is arranged obliquely relative to the first total internal reflection surface and is close to the incident end of the light;

[0007] The first end of the reflection surface is located on a side of the first total internal reflection surface away from the second total internal reflection surface, and the second end of the reflection surface is located between the first total internal reflection surface and the second total internal reflection surface; and a set distance is spaced between the second end of the reflection surface and the second total internal reflection surface;

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

[0009] The light within the incident angle enters the optical device through the light incident end, is reflected once by the reflection surface to the second total internal reflection surface, and spreads over the light guide to achieve total internal reflection propagation; wherein the incident angle is at least 50% of the maximum incident angle;

[0010] The edge light that is obliquely incident to the second end of the reflective surface within the incident angle is reflected twice by the reflective surface and then reflected to between the first end of the reflective surface and the first total internal reflection surface.

[0011] In the above technical solution, a reflector is arranged at an angle relative to the first total internal reflection surface, so that the light incident into the light guide can be reflected to between the first total internal reflection surface and the second total internal reflection surface for propagation. At the same time, through the setting of the first end and the second end of the reflection surface, the reflected light can be spread all over the light guide, thereby achieving uniform arrangement of the light. In addition, the stray light reflected for the second time by the reflection surface can be filtered, thereby improving the optical performance of the optical device and improving the effect of the light guide in realizing near-eye display.

[0012] In a specific possible implementation scheme, it also includes an extinction surface, one end of which 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 reflected twice by the reflecting surface.

[0013] In a specific embodiment, the matte surface is a black light-absorbing surface or a rough surface; wherein,

[0014] When the matte surface is a rough surface, the roughness of the rough surface is greater than the roughness of the reflective surface.

[0015] In a specific possible implementation manner, the matt surface is arranged to be inclined relative to the first total internal reflection surface, and the matt surface forms an obtuse angle with the first total internal reflection surface.

[0016] In a specific possible implementation manner, a connecting surface is further included, 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 an end of the second total internal reflection surface close to the second end of the reflecting surface.

[0017] In a specific possible implementation manner, it further comprises a polyhedral structure, wherein the reflecting surface, the matting surface and the connecting surface are surfaces of the polyhedral structure;

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

[0019] In a specific possible implementation manner, the length direction of the first total internal reflection surface is a first direction;

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

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

[0022] in,

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

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

[0025] a is an angle that is 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 and l are redundancy.

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

[0029] The distance L between the end point of the first total internal reflection surface close to the reflection surface and the second end of the reflection 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 reflection surface and the second total internal reflection surface;

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

[0034] a is an angle that is 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 a specific possible implementation manner, the length direction of the first total internal reflection surface is a first direction;

[0038] The distance L between the end point of the first total internal reflection surface close to the reflection surface and the second end of the reflection 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 reflection surface and the second total internal reflection surface;

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

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

[0044] d is the 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 and l are redundancy.

[0047] In a second aspect, a near-eye display device is provided, the near-eye display device comprising a light generator and any one of the optical devices described above; wherein:

[0048] The light generated by the light generator is incident on the light guide member only at the light incident end.

[0049] In the above technical solution, a reflector is arranged at an angle relative to the first total internal reflection surface, so that the light incident into the light guide can be reflected to between the first total internal reflection surface and the second total internal reflection surface for propagation. At the same time, through the setting of the first end and the second end of the reflection surface, the reflected light can be spread all over the light guide, thereby achieving uniform arrangement of the light. In addition, the stray light reflected by the reflection surface for the second time can be filtered, thereby improving the optical performance of the optical device and improving the effect of the light guide in realizing near-eye display. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 A schematic diagram of an application scenario of an optical device provided in an embodiment of the present application;

[0051] Figure 2 A schematic diagram of the incident angle of the optical device provided in the embodiment of the present application;

[0052] Figure 3 A schematic diagram of the structure of an optical device provided in an embodiment of the present application;

[0053] Figure 4 A schematic diagram of light propagation in an optical device provided in an embodiment of the present application;

[0054] Figure 5 Another schematic diagram of light propagation in an optical device provided in an embodiment of the present application;

[0055] Figure 6 Another schematic diagram of light propagation in an optical device provided in an embodiment of the present application;

[0056] Figure 7 Another schematic diagram of light propagation in an optical device provided in an embodiment of the present application;

[0057] Figure 8 A schematic diagram of a specific structure of an optical device provided in an embodiment of the present application;

[0058] Fig. 9Another specific structural schematic diagram of the optical device provided in an embodiment of the present application. DETAILED DESCRIPTION

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

[0060] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in one or more embodiments of this specification should be understood by people with ordinary skills in the field to which this disclosure belongs. The "first", "second" and similar words used in one or more embodiments of this specification do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0061] To facilitate understanding of the optical device provided in the embodiment of the present application, its application scenario is first described. The optical device provided in the embodiment of the present application is applied to AR (Augmented Reality) or VR (Virtual Reality) equipment. When the current optical waveguide propagates light, it is very easy to have uneven light, which affects the display effect of AR or VR equipment. To this end, the embodiment of the present application provides an optical device to improve the light propagation effect of the optical device, thereby improving the display effect of AR or VR equipment. It is described in detail below in conjunction with specific drawings and embodiments.

[0062] refer to Figure 1 , Figure 1 The application scenario of the optical device provided by the embodiment of the present application is shown. When the optical scenario provided by the embodiment of the present application is applied, the light emitted by the light generator 200 is injected into the light guide 110 in the optical device 100, and the light is coupled into the light guide 110 between the two total internal reflection surfaces through the reflective surface 120 of the optical device 100 for total internal reflection to propagate the light, and the light is coupled out of the light guide 110 through the coupling element 130 in the light guide 110 to propagate into the user's eyes. Among them, the light emitted by the light generator 200 can be a collimated image. If the light generator 200 is an optical collimation device, or can also be a light source generator component with scanning properties, it is not specifically limited in the embodiment of the present application.

[0063] For the convenience of describing the optical device 100 provided in the embodiment of the present application, the maximum incident angle is first defined. When the light generator 200 emits light to the optical device 100, the maximum angle at which the light generator 200 is incident on the optical device 100 is defined as the maximum incident angle. Figure 2 The reference light shown in FIG. 1 is a reference light beam, and the edge light beam emitted by the light generator 200 forms a maximum incident angle incident on the optical device 100, that is, the maximum incident angle is determined by the edge light beam of the light generator 200 (eg, Figure 2 The angle α shown in FIG. 1 is the angle formed by the two edge rays. Figure 2 The incident angle is also given as an example. Figure 2 The dashed line example in the figure shows an incident angle β, where β≤α. Figure 2 Also illustrated is an angle a which is half of the maximum incident angle, a=1 / 2α, that is, the angle obtained by dividing the maximum incident angle by the angle bisector.

[0064] refer to Figure 3 , Figure 3 1 is a schematic diagram of the structure of the optical device provided in the embodiment of the present application. The main structure of the optical device provided in the embodiment of the present application includes a light guide 110 and a reflective surface 120. The light guide 110 has a first total internal reflection surface 111 and a second total internal reflection surface 112 which are parallel to each other. Figure 1 As shown in FIG. 1 , the second total internal reflection surface 112 is located on a side close to the light generator 200, and the first total internal reflection surface 111 is located on a 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 light propagation.

[0065] When light is incident, the light guide 110 has a light incident end and a light emitting end ( Figure 3 Not marked, please refer to Figure 1 When the light incident end and the light exit end are specifically arranged, the light incident end and the light exit end are arranged along the length direction of the light guide 110 and are located at two ends opposite to the second total internal reflection surface 112. The light incident from the light incident end to the light guide 110 can be coupled into the first total internal reflection surface 111 and the second total internal reflection surface 112 through the reflection surface 120 for total internal reflection.

[0066] When the reflective surface 120 is specifically formed, it can be formed by directly coating a reflective layer on the light guide 110, or attaching a reflective layer to the light guide 110 as the reflective surface 120. In the embodiment of the present application, no specific limitation is made, and it is only necessary to couple the light into between the first total internal reflection surface 111 and the second total internal reflection surface 112.

[0067] When the reflective surface 120 is specifically set, the reflective surface 120 is set obliquely relative to the length direction of the light guide 110, that is, the reflective surface 120 is set obliquely relative to the first total internal reflection surface 111. In addition, since the reflective surface 120 is used as a coupling device, the reflective surface 120 is set close to the incident end of the light to ensure that the light can be reflected by the reflective surface 120 to between the first total internal reflection surface 111 and the second total internal reflection surface 112 to achieve light coupling.

[0068] When the reflective surface 120 is inclined relative to the first total internal reflection surface 111, the reflective 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. Figure 3 There is an intersection (as shown by the dotted line in the figure), 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 the first end O1 protruding outside the first total internal reflection surface 111. The second end O2 of the reflecting surface 120 is the lower end, which is located between the first total internal reflection surface 111 and the second total internal reflection surface 112, and there is a set distance between the second end O2 of the reflecting surface 120 and the second total internal reflection surface 112, that is, the second end O2 of the reflecting surface 120 does not intersect with the second total internal reflection surface 112. Figure 3 The placement direction of the light guide 110 in the figure is taken as the reference direction, and the first end O1 and the second end O2 of the reflective surface 120 are arranged in a manner of being higher on the left and lower on the right, so that the reflection direction of the reflective surface 120 is toward the inside of the light guide 110, and the light reflected by the reflective surface 120 can enter the light guide 110.

[0069] In addition, the optical device further includes two exposed surfaces, which are used to connect the reflective surface 120 and two total internal reflection surfaces (the first total internal reflection surface 111 and the second total internal reflection surface 112). Exemplarily, one of the exposed surfaces is a matte surface 114, which is located between the first total internal reflection surface 111 and the reflective surface 120 and is used to connect the first total internal reflection surface 111 and the reflective surface 120. Exemplarily, one end of the matte surface 114 is connected to the first end O1 of the reflective surface 120, and the other end is fixedly connected to an end of the first total internal reflection surface 111 close to the reflective surface 120, and is used to absorb light that is reflected twice by the reflective surface 120 and is reflected between the first end O1 of the reflective surface 120 and the first total internal reflection surface 111, that is, absorbs light that is reflected twice by the reflective surface 120. The light reflected on both sides by the reflective surface 120 is stray light in the light guide 110.

[0070] When the matt surface 114 is used to absorb the light reflected from the reflective surface 120 to the space between the first total internal reflection surface 111 and the reflective surface 120, different methods can be used. Exemplarily, the matt surface 114 is a black light-absorbing surface or a rough surface. When the matt surface 114 is a black light-absorbing surface, the light-absorbing property of black can be used to absorb the light, thereby reducing the reflection of the light. When the matt surface 114 is a rough surface, the roughness of the rough surface is greater than the roughness of the reflective surface 120, so as to reduce the light from entering between the first total internal reflection surface 111 and the second total internal reflection surface 112 through diffuse reflection formed by the rough surface. It should be understood that the matt in the present application does not refer to the elimination of light, but to reduce the propagation of light between the first total internal reflection surface 111 and the second total internal reflection surface 112 by absorbing light or by different methods such as diffuse reflection and transmission.

[0071] Another exposed surface is located between the second total internal reflection surface 112 and the reflection surface 120, and serves as a connecting surface 113 to connect the second total internal reflection surface 112 and the reflection surface 120. Exemplarily, one end of the connecting surface 113 is connected to the second end O2 of the reflection surface 120, and the other end of the connecting surface 113 is connected to an end of the second total internal reflection surface 112 close to the second end O2 of the reflection surface 120. The connecting surface 113 may also be an extinction surface, thereby reducing the reflection of the light irradiated thereon, so as to reduce the stray light from entering between the first total internal reflection surface 111 and the second total internal reflection surface 112. When the connecting surface 113 is an extinction surface, reference may be made to the description of the extinction surface in the above text, which will not be repeated here.

[0072] It should be understood that when connecting the first total internal reflection surface 111, the second total internal reflection surface 112, and the reflective surface 120, it is not limited to the two exposed surfaces in the above example, and other exposed surfaces can also be used to achieve the connection between 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 through two or three exposed surfaces; the second total internal reflection surface 112 and the reflective surface 120 are connected through two or three exposed surfaces. For the convenience of description, in the embodiment of the present application, the first total internal reflection surface 111, the second total internal reflection surface 112, and the reflective surface 120 in the above example are connected through the extinction surface 114 and the connection surface 113 as an example.

[0073] For the convenience of description, the intersection point of the extinction surface 114 and the first total internal reflection surface 111 is defined as point O3, and the intersection point of the reflection surface 120 and the connection surface 113 is defined as point O2.

[0074] When the reflective surface 120 couples the light to between the first total internal reflection surface 111 and the second total internal reflection surface 112, in order to improve the uniformity of the light, the reflective surface 120 needs to cooperate with the first total internal reflection surface 111 and the second total internal reflection surface 112. Specifically, the first end and the second end of the reflective surface 120 satisfy: the light within the incident angle enters the optical device 100 through the incident end of the light, and then reflects once through the reflective surface 120 to the second total internal reflection surface 112, and spreads all over the light guide 111, so as to achieve total internal reflection propagation. Among them, the incident angle can be referred to Figure 2 In the embodiment of the present application, 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 within the above incident angles is coupled into between the first total internal reflection surface 111 and the second total internal reflection surface 112 through the reflection surface 120, the light covers the light guide 110.

[0075] For example, Figure 4 Take the ray propagation shown in as an example, Figure 4 The schematic diagram illustrates that light is coupled into the first total internal reflection surface 111 and the second total internal reflection surface 112 through the reflection surface 120 .

[0076] When the light perpendicular to the second total internal reflection surface 112 is incident on the optical device 100, the light has a certain aperture. When the light is incident on the reflection surface 120, edge rays that limit the aperture appear, such as: the dashed lines with arrows and the solid lines with arrows represent the edge rays of the light, respectively. For the convenience of description, the edge rays indicated by the dashed lines with arrows are named as the first edge rays S1, and the edge rays indicated by the solid lines with arrows are named as the second edge rays S2.

[0077] First, the first edge light S1 is described. The first edge light S1 is incident on the position of the reflection surface 120 close to the second end O2. After being reflected by the reflection surface 120, it is reflected to the second total internal reflection surface 112, and then 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 has the total internal reflection property as the endpoint of the first total internal reflection surface 111. The first edge light 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 a total internal reflection manner.

[0078] The second edge light S2 is incident on the reflective surface 120 at a position close to the first end O1, and then reflected by the reflective surface 120, reflected to the intersection point (point O3) of the first total internal reflection surface 111 and the 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.

[0079] It can be seen from the above description that 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 basically overlap, and other light rays between the first edge light S1 and the second edge light S2 are also located between the first edge light S1 and the second edge light S2 when propagating in the light guide 110. In this case, it can be considered that the light is basically completely filled in the light guide 110. If the light illumination is detected on the second total internal reflection surface 112, it means that basically the entire second total internal reflection surface 112 is illuminated by the coupled light. This state is also called the light filling the light guide 110, thereby improving the uniformity of the light when propagating in the light guide 110.

[0080] 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 in propagating light. The so-called stray light refers to the light that does not meet the total internal reflection requirements when the light propagates between the first total internal reflection surface 111 and the second total internal reflection surface 112. Figure 5 As shown in Figure 5Two different light rays are exemplified, namely, light ray S3 and light ray S4, where S3 is stray light. When the light propagates, light ray S3 is the light ray that enters between the first total internal reflection surface 111 and the second total internal reflection surface 112 after being reflected twice by the reflection surface 120, that is, after light ray S3 is reflected by the reflection surface 120 to the second total internal reflection surface 112, it is then reflected by the second total internal reflection surface 112 to the reflection surface 120, and is reflected by the reflection surface 120 to between the first total internal reflection surface 111 and the second total internal reflection surface 112. Light ray S4 is the light ray that enters between the first total internal reflection surface 111 and the second total internal reflection surface 112 after being reflected once by the reflection surface 120. By comparing light S3 and light S4, it can be seen that the reason for the stray light is that the light is reflected multiple times by the reflection surface 120, so that after it enters between the first total internal reflection surface 111 and the second total internal reflection surface 112, it does not meet the total internal reflection angle requirement (refer to light S3 and light S4), and this light becomes stray light.

[0081] Referring to the light S3 and the light S4, when the incident point of the light S3 is close to the intersection point O2 of the reflection surface 120 and the connection surface 113, the following phenomenon may occur easily: Figure 5 Similar situation of being reflected by the reflecting surface 120 times (in Figure 5 In this case, stray light will be generated when the reflected light 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 a portion of the stray light of the secondary reflection (the secondary reflection and multiple reflection in this application refer to the reflection of the reflected surface 120 twice or multiple times) through the extinction surface 114. At the same time, the intersection point O2 of the reflection surface 120 and the connecting surface 113 also has a certain height to ensure that the stray light will not pass through the junction of the first total internal reflection surface 111 and the extinction surface 114 and enter the light guide 110.

[0082] Therefore, when the reflective surface 120 provided in the embodiment of the present application is set, the first end and the second end of the reflective surface 120 should satisfy: the edge light within the incident angle that is obliquely incident to the second end O2 of the reflective surface 120 is reflected twice by the reflective surface 120 and then reflected to between the first end O1 of the reflective surface 120 and the first total internal reflection surface 111. That is, after the light within the incident angle is reflected multiple times by the reflective surface 120, the setting of the reflective surface 120 can prevent the stray light from entering between the first total internal reflection surface 111 and the second total internal reflection surface 112, thereby filtering out the stray light, and the specific filtering method is absorption or diffuse reflection by the extinction plane, such as the extinction method mentioned above.

[0083] It can be seen from the above description that the optical device provided in the embodiment of the present application can reflect the light incident into the light guide 110 to propagate between the first total internal reflection surface 111 and the second total internal reflection surface 112 by using the reflective surface 120 to be tilted relative to the first total internal reflection surface 111. And considering the propagation effect of the light in the optical device, the first end O1 and the second end O2 of the reflective surface 120 are set so that the reflected light can be spread all over the light guide 110, thereby achieving uniform arrangement of the light. In addition, the stray light reflected multiple times by the reflective surface 120 can be filtered, thereby improving the optical performance of the optical device and improving the effect of the light guide 110 in realizing near-eye display.

[0084] When the first end O1 and the second end O2 of the reflective surface 120 are specifically set, they are specifically related to parameters such as the thickness of the light guide 110 , the inclination angle of the reflective surface 120 , and the intersection point of the first total internal reflection surface 111 and the extinction surface 114 .

[0085] refer to Figure 6 As shown in Figure 6 Some parameters related to the reflective surface 120 are defined in Figure 6 The parameters in are described. Among them, 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 angle between the reflection surface 120 and the second total internal reflection surface 112; a is an angle of half the maximum incident angle, refer to 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. The first direction is the length direction of the light guide 110, that is, L is the distance between the intersection point O3 of the first total internal reflection surface 111 and the extinction surface 114 and the second end (point O2) of the reflection surface 120 along the first direction.

[0086] When the reflecting surface 120 is specifically set, L satisfies:

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

[0088] Continue to refer Figure 6When the light S5 enters the light guide 110, its intersection point with the second total internal reflection surface 112 is O8. After entering the light guide 110, it irradiates the second end O2 of the reflection surface 120, and then is reflected by the reflection surface 120 to the second total internal reflection surface 112, and then is reflected by the second total internal reflection surface 112 to the reflection surface 120 (the intersection point with the reflection surface is O9), and then is reflected by the reflection surface 120 twice to the intersection point O3 of the first total internal reflection surface 111 and the extinction surface 114. In order to prevent it from entering between the first total internal reflection surface 111 and the second total internal reflection surface 112, it should be ensured that the reflection surface 120 is set to meet the following conditions: the light is located between O1 and O3, that is, the extinction surface 114 can absorb the light after the second reflection of the light S5.

[0089] For ease of understanding, some reference lines are introduced based on the mirror principle of light. The reflected light of light S5 is mirrored with reference to the reflection surface 120 to obtain the corresponding dotted line. In addition, the second total internal reflection surface 112 is also mirrored with reference to the reflection surface 120, and the reflection surface 120, the second total internal reflection surface 112 and its mirror surface are extended to the intersection, and the intersection point is O7. The intersection point of the mirror light of light S5 and the mirror 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 from the second end point O2 of the reflection surface 120 to the second total internal reflection surface 112 (line segment O2O5, O5 is the intersection of L1 and the second total internal reflection surface 112), and its length is H; L2 is a vertical line segment from the intersection point O4 to the second total internal reflection surface 112 (line segment O4O6, O6 is the intersection of L2 and the second total internal reflection surface 112), and its length is C. The length of the light S5 propagating from 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 S5 reflected by the reflection 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 second reflection of the light S5 from the reflecting surface 120 to O3 is D, that is, the line segment O3O9; then according to the relationship between the reflection angles of the light and the relationship between the mirror images, the following formula can be obtained:

[0090]

[0091]

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

[0093]

[0094] L = DB*sina, Formula 5;

[0095] Substituting formula 1 and formula 2 into formula 3, we can get:

[0096]

[0097] Substituting formula 4 into formula 5 yields:

[0098]

[0099] From the above description, it can be known that when the light S5 is reflected twice to the intersection point O3 of the first total internal reflection surface 111 and the extinction surface 114, it is a critical state that the light S5 can enter between the first total internal reflection surface 111 and the second total internal reflection surface 112 after the second reflection. The length of L calculated by the above formula is the length of L corresponding to the above critical state. In order to eliminate the stray light of the second reflection, when setting L, it satisfies Taking into account some processing errors and involving some redundancy, the formula obtained is: Wherein l is redundancy, and for example, l can be between 0 and 0.3 mm, such as l can be different values ​​such as 0.1, 0.2, and 0.3.

[0100] refer to Figure 7 To ensure that when the light enters the light guide 110, when the coupled light is incident on the light guide 110 at another angle, it can be ensured that the light can cover the entire light guide 110, when L is set, it satisfies: L>(H+d)*tan(2b+a)-k.

[0101] exist Figure 7 The reflection surface 120 and the second total internal reflection surface 112 are extended to meet each other, the meeting point 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 S6 when it is irradiated to the reflection surface 120 is a( Figure 6 and Figure 7 In the figure, although the angles of light rays S5 and S6 are both a, their inclination directions are different). After entering the light guide 100, they are reflected by the reflection surface 120 to the second total internal reflection surface 112 (the intersection point is O10). In addition, two vertical lines are introduced at points O3 and O2, and their 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 = H*tan(2b+a), the length of O10O12 = d*tan(2b+a);

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

[0104] To ensure that the light can be incident on 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 redundancy is involved. Therefore, the formula obtained is: L>(H+d)*tan(2b+a)-k. Wherein, k is the processing redundancy. For example, k can be between 0 and 0.3 mm. For example, k can be different values ​​such as 0.1, 0.2, 0.3, etc.

[0106] In another optional solution, considering the requirements of different maximum incident angles, when it is not necessary for all light rays within the maximum incident angle to meet the requirements of eliminating stray light and covering the entire light guide, the corresponding design meets the following conditions:

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

[0108]

[0109] Wherein, j is a coefficient, 50%≤j≤1. For example, j can be in different ranges such as 50%, 60%, 70%, 80%, 90%, 1, etc. For other parameters, please refer to Figure 6 and Figure 7 See the relevant instructions in .

[0110] In another variation, based on the previous variation, redundancy and incident angle can be considered at the same time. Then the corresponding formula can be transformed into:

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

[0112]

[0113] Among them, j is the coefficient, 50%≤j≤1; k and l are redundancy. For other parameters, please refer to Figure 6 and Figure 7 See the relevant instructions in .

[0114] It can be seen from the above-mentioned different examples that by setting the reflective surface 120, the light within the incident angle (at least 50% of the maximum incident angle) incident into the optical device can be filled with light and stray light can be reduced, thereby improving the propagation effect of 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 implementation, when the matt surface 114 is specifically set, the matt surface 114 is set to be inclined relative to the first total internal reflection surface 111, and the matt surface 114 forms an obtuse angle with the first total internal reflection surface 111. That is, when the matt surface 114 is set, the matt surface 114 can be inclined relative to both the first total internal reflection surface 111 and the reflection surface 120, or perpendicular to one of the surfaces. When this arrangement is adopted, a shorter length of the reflection surface 120 can be used to meet the requirements of 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 also meet the requirement that all light incident on the light guide 110 can be irradiated to the reflection surface 120 and coupled through the reflection surface 120.

[0116] In an optional solution, when the connection surface 113 is specifically provided, the connection surface 113 is provided obliquely relative to the second total internal reflection surface 112, and the angle between the connection surface 113 and the reflection surface 120 is an obtuse angle. That is, the connection surface 113 is inclined toward the outside of the light guide 110, so that when the light enters the light guide 110 at an inclined angle, it can irradiate the second end of the reflection surface 120, thereby reducing the length of the reflection surface 120.

[0117] In a specific embodiment, the optical device further comprises a polyhedron structure, the reflective surface, the matte surface and the connection surface are surfaces of the polyhedron structure, and the polyhedron is bonded to the light guide to facilitate the preparation of the optical device. In the specific bonding, different methods can be used. Figure 8 and Fig. 9 As shown in FIG. 1 , the reflective surface 120, the matte surface 114 and the connecting surface 113 are made of a polyhedral structure 140 of the same material as the light guide 110. Figure 8 As shown by the dotted line in the figure, the entire optical device is divided into a light guide 110 and a polyhedron structure 140. The light guide 110 and the polyhedron structure 140 are made of 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 extinction surface 114 and the connection surface 113 are prepared on the polyhedron structure 140. When forming the optical device, the light guide 110 and the polyhedron structure 140 are bonded and fixed, so that the reflection surface 120, the extinction surface 114, and the connection surface 113 are connected to the first total internal reflection surface 111 and the second total internal reflection surface 112 respectively. Similarly, refer to Fig. 9 As shown by the dotted line in Fig. 9 Another division method of the light guide 110 and the polyhedral structure 140 is illustrated in FIG. Figure 8 The principle is the same as shown in , and will not be repeated here.

[0118] Of course, in addition to the above-mentioned methods, other methods may be used to set the reflective surface 120, the matte surface 114 and the connecting surface 113, which will not be described one by one here.

[0119] The embodiment of the present application further provides a near-eye display device, which includes a light generator and any one of the above optical devices; wherein,

[0120] Only the light incident end of the light generated by the light generator is incident on the light guide member 110 .

[0121] In the above technical solution, the reflective surface 120 is tilted relative to the first total internal reflection surface 111, so that 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. At the same time, through the setting of the first end and the second end of the reflective surface 120, the reflected light can be spread all over the light guide 110, so as to achieve uniform arrangement of the light. In addition, the stray light reflected by the reflective surface 120 for the second time can be filtered, so as to improve the optical performance of the optical device and improve the effect of the light guide 110 in realizing near-eye display.

[0122] One or more embodiments of this specification are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this specification should be included in the scope of protection of this disclosure.

[0123] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in 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 based on the protection scope of the claims.

Claims

1. An optical device, characterized in that: include: A light guide and a reflective surface; wherein, 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 a light incident end and a light emitting end which are opposite to each other; The reflection surface is arranged obliquely relative to the first total internal reflection surface and is close to the incident end of the light; The first end of the reflection surface is located on a side of the first total internal reflection surface away from the second total internal reflection surface, and the second end of the reflection surface is located between the first total internal reflection surface and the second total internal reflection surface; and a set distance is spaced between the second end of the reflection surface and the second total internal reflection surface; The first end and the second end of the reflecting surface satisfy: The light within the incident angle enters the optical device through the light incident end, is reflected once by the reflection surface to the second total internal reflection surface, and spreads over 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 that is obliquely incident to the second end of the reflective surface within the incident angle is reflected twice by the reflective surface and then reflected to between the first end of the reflective surface and the first total internal reflection surface.

2. The optical device according to claim 1, characterized in that It also includes an extinction surface, one end of which 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 reflected twice by the reflecting surface.

3. The optical device according to claim 2, characterized in that: The matte surface is a black light-absorbing surface or a rough surface; wherein, When the matte surface is a rough surface, the roughness of the rough surface is greater than the roughness of the reflective surface.

4. The optical device according to claim 2, characterized in that: 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.

5. The optical device according to claim 2, characterized in that: It also includes a connecting surface, one end of which is connected to the second end of the reflecting surface, and the other end of which is connected to an end of the second total internal reflection surface close to the second end of the reflecting surface.

6. The optical device according to claim 5, characterized in that: It also includes a polyhedron structure, wherein the reflecting surface, the matting surface and the connecting surface are surfaces of the polyhedron structure; The polyhedron is bonded and connected to the light guide.

7. 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 first total internal reflection surface close to the reflection surface and the second end of the reflection surface in the first direction satisfies: L>(H+d)*tan(2b+a)-k; and in, H is the vertical distance between the second end of the reflection surface and the second total internal reflection surface; b is the angle between the reflection surface and the second total internal reflection surface; a is an angle that is 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.

8. 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 first total internal reflection surface close to the reflection surface and the second end of the reflection surface in the first direction satisfies: L>(H+d)*tan(2b+ja); H is the vertical distance between the second end of the reflection surface and the second total internal reflection surface; b is the angle between the reflection surface and the second total internal reflection surface; a is an angle that is 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 first total internal reflection surface close to the 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 angle between the reflection surface and the second total internal reflection surface; a is an angle that is 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 and l are redundancy.

10. A near-eye display device, characterized in that: It comprises a light generator and an optical device as claimed in any one of claims 1 to 9; wherein: The light generated by the light generator is incident on the light guide member only at the light incident end.

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