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; and the length of the reflecting surface meets the requirement of a set formula. The reflecting mirror is obliquely arranged relative to the first total internal reflection surface, so that light rays entering the light guide part can be reflected to the position between the first total internal reflection surface and the second total internal reflection surface to be transmitted, meanwhile, due to the arrangement of the first end and the second end of the reflecting surface, the reflected light rays can be fully paved in the light guide part, and the light guide part is more compact. In addition, stray light secondarily reflected by the reflecting surface can be filtered, so that the optical performance of the optical device is improved, and the effect of the light guide part during near-eye display is improved.

Description

[0001] This application is a divisional application. The original application has the application number 202311331529.7, the application date is October 13, 2023, and the title is "An optical device and a near-eye display device". Technical Field

[0002] This application relates to the field of optical technology, and in particular to an optical device and a near-eye display device. Background Technology

[0003] The application of various near-eye display systems, such as AR (Augmented Reality) and VR (Virtual Reality), is becoming increasingly common. However, users are placing higher demands on the technical aspects of these near-eye display systems, particularly regarding the quality of the displayed images. Currently, however, near-eye display systems still suffer from uneven light propagation and stray light during the light guide process. Summary of the Invention

[0004] This application provides an optical device and a near-eye display device that improves the propagation effect of light within the optical device, thereby enhancing the display effect.

[0005] This application provides an optical device, which includes: a light guide and a reflective surface; wherein... The light guide includes a first total internal reflection surface and a second total internal reflection surface that are parallel to each other; the second total internal reflection surface has a light incident end and an exit end facing each other. The reflective surface is inclined relative to the first total internal reflective surface and is close to the light incident end; The first end of the reflective surface is located on the side of the first fully internal reflective surface that is away from the second fully internal reflective surface, and the second end of the reflective surface is located between the first fully internal reflective surface and the second fully internal reflective surface; and there is a set distance between the second end of the reflective surface and the second fully internal reflective surface. The length direction of the first total internal reflective surface is the first direction; The distance L between the endpoint of the first total internal reflective surface near the reflective surface and the second end of the reflective surface in the first direction satisfies: ;and ; Alternatively, the distance L between the endpoint of the first total internal reflective surface near the reflective surface and the second end of the reflective surface in the first direction satisfies: ; ; Alternatively, the distance L between the endpoint of the first total internal reflection surface near the reflecting surface and the second end of the reflecting surface in the first direction satisfies: ; ; Where H is the vertical distance between the second end of the reflecting surface and the second total internal reflecting surface; b is the angle between the reflecting surface and the second total internal reflecting surface; a is an angle that is half of the maximum incident angle; d is the vertical distance between the first total internal reflective surface and the second total internal reflective surface; j is a coefficient, and 50% ≤ j ≤ 1; k and l are redundant values.

[0006] In the above technical solution, by using a reflector that is tilted relative to the first total internal reflection surface, the light incident on the light guide can be reflected to propagate between the first and second total internal reflection surfaces. At the same time, by setting the first and second ends of the reflector, the reflected light can be spread throughout the light guide, thereby achieving uniform light distribution. In addition, stray light reflected by the reflector can be filtered out, thereby improving the optical performance of the optical device and enhancing the effect of the light guide in achieving near-eye display.

[0007] In one specific implementation, an matte surface is further included, one end of which is connected to the first end of the reflective surface, and the other end is fixedly connected to the end of the first total internal reflective surface near the reflective surface, and is used to absorb light that has been reflected twice by the reflective surface.

[0008] In one specific implementation, 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.

[0009] In one specific implementation, the matting surface is inclined relative to the first total internal reflection surface, and the matting surface forms an obtuse angle with the first total internal reflection surface.

[0010] In one specific implementation, a connecting surface is further included, one end of which is connected to the second end of the reflective surface, and the other end of which is connected to one end of the second total internal reflective surface near the second end of the reflective surface.

[0011] In one specific implementation scheme, it further includes a polyhedral structure, wherein the reflective surface, the matting surface, and the connecting surface are surfaces of the polyhedral structure; The polyhedral structure is bonded to the light guide.

[0012] In one specific implementation, the first fully internal reflective surface is connected to the reflective surface via two or three exposed surfaces; the second fully internal reflective surface is connected to the reflective surface via two or three exposed surfaces.

[0013] Secondly, a near-eye display device is provided, comprising a light generator and the optical device described in any of the preceding claims; wherein, The light generated by the light generator enters the light guide only at the light incident end.

[0014] In the above technical solution, by using a reflector that is tilted relative to the first total internal reflection surface, the light incident on the light guide can be reflected to propagate between the first and second total internal reflection surfaces. At the same time, by setting the first and second ends of the reflector, the reflected light can be spread throughout the light guide, thereby achieving uniform light distribution. In addition, stray light reflected by the reflector can be filtered out, thereby improving the optical performance of the optical device and enhancing the effect of the light guide in achieving near-eye display. Attached Figure Description

[0015] Figure 1 This is a schematic diagram illustrating the application scenarios of the optical devices provided in the embodiments of this application; Figure 2 A schematic diagram of the incident angle of the optical device provided in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the optical device provided in the embodiments of this application; Figure 4 A schematic diagram illustrating the propagation of light within an optical device, provided as an embodiment of this application; Figure 5 This is another schematic diagram of light propagation within an optical device, provided as an embodiment of this application; Figure 6 This is another schematic diagram of light propagation within an optical device, provided as an embodiment of this application; Figure 7 This is another schematic diagram of light propagation within an optical device, provided as an embodiment of this application; Figure 8 This is a schematic diagram of a specific structure of an optical device provided in an embodiment of this application; Figure 9 This is a schematic diagram of another specific structure of the optical device provided in the embodiments of this application. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0017] It should be noted that, unless otherwise defined, the technical or scientific terms used in one or more embodiments of this specification should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar words used in one or more embodiments of this specification do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0018] To facilitate understanding of the optical device provided in this application embodiment, its application scenario is first described. The optical device provided in this application embodiment is applied in AR (Augmented Reality) or VR (Virtual Reality) devices. Current optical waveguides are prone to uneven light propagation, affecting the display effect of AR or VR devices. Therefore, this application embodiment provides an optical device to improve the light propagation effect of the optical device, thereby improving the display effect of AR or VR devices. A detailed description follows with reference to specific drawings and embodiments.

[0019] refer to Figure 1 , Figure 1 This illustration shows an application scenario of the optical device provided in this application embodiment. In the application scenario provided by this application embodiment, the light emitted by the light generator 200 enters the light guide 110 in the optical device 100, and is coupled through the reflecting surface 120 of the optical device 100 to the two total internal reflection surfaces of the light guide 110 for total internal reflection to propagate the light. The light is then coupled out of the light guide 110 through the coupling element 130 in the light guide 110 to propagate to the user's eye. The light emitted by the light generator 200 can be a collimated image. The light generator 200 can be an optical collimating device, or it can also be a light source generator assembly with scanning properties; no specific limitations are made in this application embodiment.

[0020] To facilitate the description of the optical device 100 provided in this application embodiment, the maximum incident angle is first defined. When light is emitted from the light generator 200 into the optical device 100, the maximum angle at which light from the light generator 200 enters the optical device 100 is defined as the maximum incident angle. For example... Figure 2 The reference ray shown, the edge rays emitted by the ray generator 200 form the maximum incident angle to the optical device 100, that is, the maximum incident angle is determined by the edge rays of the ray generator 200 (e.g., Figure 2 The angle α shown is the angle formed by the two edge rays. Additionally, in... Figure 2 The example also illustrates the angle of incidence, such as... Figure 2 The incident angle β is shown as an example of the dashed line, where β ≤ α. Figure 2 The example also shows half the angle α of the maximum incident angle, where α = 1 / 2α, which is the angle obtained by dividing the angle by the angle bisector of the maximum incident angle.

[0021] refer to Figure 3 , Figure 3 A schematic diagram of the structure of an optical device provided in an embodiment of this application is shown. The main structure of the optical device provided in this application includes a light guide 110 and a reflecting surface 120. The light guide 110 has a first total internal reflection surface 111 and a second total internal reflection surface 112 that are parallel to each other. Figure 1 As shown, the second total internal reflection surface 112 is located on the side closer to the light generator 200, while the first total internal reflection surface 111 is located on the side of the second total internal reflection surface 112 away from the light generator 200. When light propagates in the light guide 110, the light can be totally internally reflected between the first total internal reflection surface 111 and the second total internal reflection surface 112 to achieve the propagation of light.

[0022] When light is incident, the light guide 110 has a light incident end and a light exit end ( ). Figure 3 For details not marked, please refer to the following: Figure 1 (The positions of the light incident and light exit points). Specifically, the light incident and light exit points are arranged along the length of the light guide 110 and located at opposite ends of the second total internal reflection surface 112. Light rays incident from the light incident point into the light guide 110 can be coupled through the reflecting surface 120 to undergo total internal reflection between the first total internal reflection surface 111 and the second total internal reflection surface 112.

[0023] When forming the reflective surface 120, it can be formed by directly coating the reflective layer on the light guide 110, or by attaching the reflective layer to the light guide 110 as the reflective surface 120. In the embodiments of this application, no specific limitation is made, as long as light can be coupled between the first total internal reflection surface 111 and the second total internal reflection surface 112.

[0024] In the specific configuration of the reflective surface 120, the reflective surface 120 is inclined relative to the length direction of the light guide 110, that is, the reflective surface 120 is inclined relative to the first total internal reflective surface 111. In addition, since the reflective surface 120 serves as a coupling device, it is positioned near the light incident end to ensure that the light can be reflected by the reflective surface 120 to the space between the first total internal reflective surface 111 and the second total internal reflective surface 112, thereby achieving light coupling.

[0025] When the reflecting surface 120 is tilted relative to the first total internal reflecting surface 111, the reflecting surface 120 has a first end O1 and a second end O2, where the first end O1 is the high end and the second end O2 is the low end. Specifically, the extension lines of the reflecting surface 120 and the first total internal reflecting surface 111 (e.g., Figure 3 As shown by the dashed lines in the diagram, there is an intersection point. The first end O1 and the second end O2 of the reflective surface 120 are located on opposite sides of the extension line of the first total internal reflective surface 111. The first end O1 of the reflective surface 120 is located on the side of the first total internal reflective surface 111 away from the second total internal reflective surface 112; it can also be understood that the first end O1 protrudes outward from the first total internal reflective surface 111. The second end O2 of the reflective surface 120, as the lower end, is located between the first total internal reflective surface 111 and the second total internal reflective surface 112, and there is a set distance between the second end O2 of the reflective surface 120 and the second total internal reflective surface 112, meaning that the second end O2 of the reflective surface 120 and the second total internal reflective surface 112 do not intersect. Figure 3 The placement direction of the light guide 110 is the reference direction. The first end O1 and the second end O2 of the reflective surface 120 are set in a left-high and right-low manner so that the reflection direction of the reflective surface 120 faces the interior of the light guide 110 and the light reflected by the reflective surface 120 can enter the light guide 110.

[0026] In addition, the optical device includes two exposed surfaces for connecting the reflecting surface 120 to two total internal reflecting surfaces (first total internal reflecting surface 111 and second total internal reflecting surface 112). For example, one of the exposed surfaces is an extinction surface 114, located between the first total internal reflecting surface 111 and the reflecting surface 120, and used to connect the first total internal reflecting surface 111 and the reflecting surface 120. For example, one end of the extinction surface 114 is connected to the first end O1 of the reflecting surface 120, and the other end is fixedly connected to the end of the first total internal reflecting surface 111 near the reflecting surface 120, and is used to absorb light reflected twice by the reflecting surface 120 to the area between the first end O1 of the reflecting surface 120 and the first total internal reflecting surface 111, i.e., absorbing light reflected twice by the reflecting surface 120. The light reflected by the reflecting surface 120 to both sides is stray light in the light guide 110.

[0027] The aforementioned matting surface 114 can be used in different ways to absorb light reflected from the reflecting surface 120 to the area between the first total internal reflecting surface 111 and the reflecting surface 120. For example, the matting surface 114 can be a black light-absorbing surface or a rough surface. When the matting surface 114 is a black light-absorbing surface, the light-absorbing properties of black can be utilized to absorb light, thereby reducing light reflection. When the matting surface 114 is a rough surface, the roughness of the rough surface is greater than the roughness of the reflecting surface 120, so that diffuse reflection formed by the rough surface reduces the amount of light entering between the first total internal reflecting surface 111 and the second total internal reflecting surface 112. It should be understood that "matting" in this application does not refer to eliminating light, but rather reducing the propagation of light between the first total internal reflecting surface 111 and the second total internal reflecting surface 112 through different methods such as light absorption, diffuse reflection, and transmission.

[0028] Another exposed surface is located between the second total internal reflection surface 112 and the reflecting surface 120, and serves 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, while the other end of the connecting surface 113 is connected to the end of the second total internal reflection surface 112 near the second end O2 of the reflecting surface 120. This connecting surface 113 can also be an matte surface, thereby reducing the reflection of light incident upon it, thus reducing 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 matte surface, refer to the description of matte surfaces above; it will not be repeated here.

[0029] 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.

[0030] 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.

[0031] When the reflective surface 120 couples light between the first total internal reflection surface 111 and the second total internal reflection surface 112, to improve the uniformity of the light, the reflective surface 120 needs to cooperate with both the first total internal reflection surface 111 and the second total internal reflection surface 112. Specifically, the first and second ends of the reflective surface 120 satisfy the following: light rays within the incident angle that enter the optical device 100 through the light incident end are reflected once again by the reflective surface 120 to the second total internal reflection surface 112, and then cover the light guide 111 to achieve total internal reflection propagation. The incident angle can be referenced... Figure 2 The angle β is the incident angle. In this embodiment, the incident angle is at least 50% of the maximum incident angle. For example, β can be 50% of the maximum incident angle, 70% of the maximum incident angle, 90% of the maximum incident angle, or 100% of the maximum incident angle. When light rays within the above-mentioned incident angle are coupled into the space between the first total internal reflection surface 111 and the second total internal reflection surface 112 via the reflecting surface 120, the light rays completely cover the light guide 110.

[0032] 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.

[0033] 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.

[0034] First, let's describe the first edge ray S1. The first edge ray S1 is incident on the reflective surface 120 near the second end O2. After being reflected by the reflective surface 120, it is reflected to the second total internal reflection surface 112. Then, it is reflected by the second total internal reflection surface 112 to the intersection point (point O3) of the first total internal reflection surface 111 and the extinction surface 114. At this time, point O3, as the endpoint of the first total internal reflection surface 111, has the property of total internal reflection. The first edge ray S1 is reflected by the first total internal reflection surface 111 to the second total internal reflection surface 112 at point O3, and propagates between the first total internal reflection surface 111 and the second total internal reflection surface 112 in the manner of total internal reflection.

[0035] The second edge ray S2 is incident on the reflective surface 120 near the first end O1. After being reflected by the reflective surface 120, it is reflected to the intersection point (point O3) of the first total internal reflective surface 111 and the extinction surface 114, and continues to propagate to the second total internal reflective surface 112. It continues to propagate between the first total internal reflective surface 111 and the second total internal reflective surface 112 in the manner of total internal reflection.

[0036] As can be seen from the above description, when the first edge ray S1 and the second edge ray S2 propagate to point O3 and enter the space between the first total internal reflection surface 111 and the second total internal reflection surface 112 for total internal reflection, the first edge ray S1 and the second edge ray S2 essentially overlap. Other rays located between the first edge ray S1 and the second edge ray S2, when propagating within the light guide 110, are also located between the first edge ray S1 and the second edge ray S2. In this case, it can be considered that the light guide 110 is essentially completely filled. If the illuminance is measured on the second total internal reflection surface 112, it means that the entire second total internal reflection surface 112 has been illuminated by the coupled light. This state is also called light covering the light guide 110, thereby improving the uniformity of light propagation within the light guide 110.

[0037] When optical devices propagate light, it is necessary to ensure both the uniformity of light propagation and the elimination of stray light to improve the performance of the light guide 110 in propagating light. Stray light refers to light that does not meet the total internal reflection requirement when propagating between the first total internal reflection surface 111 and the second total internal reflection surface 112. (Reference) Figure 5 As shown, in 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 reflection surface 111 and the second total internal reflection surface 112. That is, ray S3 is reflected by reflective surface 120 to the second total internal reflection surface 112, then reflected again by the second total internal reflection surface 112 to reflective surface 120, and finally reflected by reflective surface 120 into the space between the first and second total internal reflection 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 reflection surfaces 111 and 112. Comparing ray S3 and ray S4, it can be seen that stray light is generated because the ray undergoes multiple reflections by reflective surface 120, causing it to enter the space between the first and second total internal reflection surfaces 111 and 112, where the required total internal reflection angle is not met (refer to ray S3 and ray S4). This type of ray is thus called stray light.

[0038] Referring to light rays S3 and S4, when the incident point of light ray S3 is close to the intersection point O2 of the reflecting surface 120 and the connecting surface 113, it is easy to see the following: Figure 5 Similar cases of reflection by a reflective surface more than 120 times (in) Figure 5 (The light is reflected twice). In this case, the reflected light will form stray light when it enters between the first total internal reflection surface 111 and the second total internal reflection surface 112. Therefore, the intersection point O3 of the extinction surface 114 and the first total internal reflection surface 111 needs to be low enough to eliminate some of the stray light from the secondary reflection (in this application, secondary reflection and multiple reflections refer to two or more reflections by the reflected surface 120) through the extinction surface 114. At the same time, the intersection point O2 of the reflecting surface 120 and the connecting surface 113 also needs to have a certain height to ensure that the stray light does not cross the boundary between the first total internal reflection surface 111 and the extinction surface 114 and enter the light guide 110.

[0039] 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.

[0040] As can be seen from the above description, the optical device provided in this application embodiment, by employing a reflective surface 120 that is tilted relative to the first total internal reflection surface 111, can reflect light incident on the light guide 110 to propagate between the first total internal reflection surface 111 and the second total internal reflection surface 112. Furthermore, considering the propagation effect of light in the optical device, the arrangement of the first end O1 and the second end O2 of the reflective surface 120 allows the reflected light to spread evenly throughout the light guide 110, thereby achieving uniform light distribution. Additionally, it can filter out stray light reflected multiple times by the reflective surface 120, thereby improving the optical performance of the optical device and enhancing the effect of the light guide 110 in achieving near-eye display.

[0041] When specifically setting the first end O1 and the second end O2 of the reflective surface 120, it is related to parameters such as the thickness of the light guide 110, the tilt angle of the reflective surface 120, and the intersection point of the first total internal reflection surface 111 and the extinction surface 114.

[0042] refer to Figure 6 As shown, in Figure 6The documentation defines some parameters related to the reflective surface 120. Firstly, regarding... Figure 6 The parameters are explained below. Specifically, point O2 is the second endpoint of reflective surface 120; d is the perpendicular distance between the first total internal reflective surface 111 and the second total internal reflective surface 112; H is the perpendicular distance between the second endpoint O2 of reflective surface 120 and the second total internal reflective surface 112; b is the angle between reflective surface 120 and the second total internal reflective surface 112; a is half the maximum incident angle, referenced... Figure 2 The relevant explanation is as follows: L is the distance between the endpoint of the first total internal reflection surface 111 near the reflection surface 120 and the second end O2 of the reflection surface 120 in the first direction. Wherein, 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.

[0043] When the reflective surface 120 is specifically configured, L satisfies: ;and Where k and l are redundancy values.

[0044] Continue to refer to Figure 6 When light ray 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 illuminates the second end O2 of the reflective surface 120, and is then reflected by the reflective surface 120 back to the second total internal reflection surface 112. It is then reflected again by the second total internal reflection surface 112 back to the reflective surface 120 (intersection point with the reflective surface is O9), and then reflected a second time by the reflective surface 120 back to the intersection point O3 of the first total internal reflection surface 111 and the extinction surface 114. To prevent light ray S5 from entering between the first total internal reflection surface 111 and the second total internal reflection surface 112, the reflective surface 120 should be configured such that the light ray is located between O1 and O3, meaning the extinction surface 114 can absorb the light ray S5 after its second reflection.

[0045] To facilitate understanding, some reference lines are introduced based on the mirror principle of light. The reflected ray of ray S5 is mirrored with reference to reflecting surface 120, resulting in the corresponding dashed line. Additionally, the second total internal reflecting surface 112 is also mirrored with reference to reflecting surface 120. Reflecting surface 120, the second total internal reflecting surface 112, and their mirror surfaces are extended to intersect at point O7. The intersection point of the mirrored ray of ray S5 and the mirror surface of the second total internal reflecting surface 112 is O4. Two auxiliary reference lines, L1 and L2, are constructed. L1 is the perpendicular line segment from the second endpoint O2 of reflecting surface 120 to the second total internal reflecting surface 112 (segment O2O5, where O5 is the intersection point of L1 and the second total internal reflecting surface 112), with a length of H. L2 is the perpendicular line segment from the intersection point O4 to the second total internal reflecting surface 112 (segment O4O6, where O6 is the intersection point of L2 and the second total internal reflecting surface 112), with a length of C. The length of ray S5 propagating within the light guide 110 to the second end O2 of the reflecting surface 120 is A (the length of line segment O2O8); the length of ray S5 after the first reflection from the reflecting surface 120 to the second total internal reflecting surface 112 is B, which is also the length of line segment O2O4 (according to the principle of mirrors). The length of ray S5 after the second reflection from the reflecting surface 120 to O3 is D, which is also the length of line segment O3O9; therefore, based on the reflection angle relationship of the rays and the mirror relationship, the following formula can be obtained: Formula 1; Formula 2; Formula 3; Formula 4; Formula 5; Substituting Formula 1 and Formula 2 into Formula 3, we get:

[0046] Substituting formula 4 into formula 5 yields:

[0047] As described above, when the light ray S5 is reflected twice and reaches the intersection point O3 of the first total internal reflection surface 111 and the extinction surface 114, it is a critical state where the light ray S5 can enter the space between the first total internal reflection surface 111 and the second total internal reflection surface 112 after secondary reflection. The length L, calculated using the above formula, is the length of L corresponding to the critical state. To eliminate stray light from secondary reflection, L is set to satisfy the following condition: Taking into account some processing errors and involving some redundancy, the resulting formula is: Where l is redundant, for example, l can be between 0 and 0.3 mm. For example, l can be different values ​​such as 0.1, 0.2, 0.3, etc.

[0048] refer to Figure 7 To ensure that when light enters the light guide 110, and when the coupled light enters the light guide 110 at a different angle, the light can cover the entire light guide 110, the setting L satisfies the following: .

[0049] exist Figure 7 The reflective surface 120 and the second total internal reflective surface 112 are extended to intersect at point O7, and the angle between the reflective surface 120 and the second total internal reflective surface 112 is b. The angle of incidence of the ray S6 when it illuminates the reflective surface 120 is a ( Figure 6 and Figure 7 Although the angles of light rays S5 and S6 are both 'a', their tilt directions are different. After entering the light guide 100, they are reflected by the reflecting surface 120 to the second total internal reflecting surface 112 (intersection point O10). Additionally, two perpendicular lines are introduced at points O3 and O2, intersecting the second total internal reflecting surface 112 at points O12 and O11, respectively. Therefore, along the first direction, L can be divided into two line segments: O11O10 and O12O10. The length of O11O10 = The length of O10O12 = ; but, .

[0050] To ensure that light can enter the first total internal reflection surface 111 and the second total internal reflection surface 112, L must satisfy: .

[0051] Taking into account some processing errors and involving some redundancy, the resulting formula is: Where k represents machining redundancy. For example, k can be between 0 and 0.3 mm. For instance, k can be different values ​​such as 0.1, 0.2, and 0.3.

[0052] In another alternative solution, considering the requirements for different maximum incident angles, when it is not necessary for the light rays within all angles of the maximum incident angle to satisfy the requirements for eliminating stray light and fully covering the light guide, the corresponding design satisfies the following conditions: ; ; Where j is a coefficient, 50% ≤ j ≤ 1. For example, j can be in different ranges such as 50%, 60%, 70%, 80%, 90%, and 1. Other parameters can be found in [reference needed]. Figure 6 and Figure 7 The relevant explanations are in the text.

[0053] In another variation, based on the previous variation, redundancy and the angle of incidence can be considered simultaneously. The corresponding formula can then be transformed into: ; ; Where j is a coefficient, 50%≤j≤1; k and l are redundancy values. Other parameters can be found in the reference. Figure 6 and Figure 7 The relevant explanations are in the text.

[0054] As can be seen from the different examples above, by setting the reflective surface 120, the light rays 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 or VR devices.

[0055] In one possible implementation, when specifically setting the extinction surface 114, the extinction surface 114 is inclined relative to the first total internal reflection surface 111, and the extinction surface 114 forms an obtuse angle with the first total internal reflection surface 111. That is, when setting the extinction surface 114, the extinction surface 114 can be inclined relative to both the first total internal reflection surface 111 and the reflecting surface 120, or perpendicular to one of the surfaces. When set in this way, the requirements for light propagation can be met by using a shorter length of the reflecting surface 120. Of course, it should be understood that even if a shorter length of the reflecting surface 120 is used, the length of the reflecting surface 120 should still be sufficient to ensure that all light incident on the light guide 110 can reach the reflecting surface 120 and be coupled through the reflecting surface 120.

[0056] In one alternative embodiment, when specifically configuring the connecting surface 113, the connecting surface 113 is inclined relative to the second total internal reflection surface 112, and the angle between the connecting surface 113 and the reflecting surface 120 is an obtuse angle. That is, the connecting surface 113 is inclined to the outside of the light guide 110, so that when light enters the light guide 110 at an inclined angle, it can illuminate the second end of the reflecting surface 120, thereby reducing the length of the reflecting surface 120.

[0057] In one specific feasible implementation, the optical device further includes a polyhedral structure, where the reflecting surface, the extinction surface, and the connecting surface are all surfaces of the polyhedral structure. This polyhedral structure is bonded to the light guide to facilitate the fabrication of the optical device. Different bonding methods can be used in the specific bonding process. For example... Figure 8 and Figure 9As shown, the reflective surface 120, the matting surface 114, and the connecting surface 113 are fabricated on a polyhedral structure 140 made of the same material as the light guide 110. According to... Figure 8 As shown by the dashed lines, the entire optical device is divided into a light guide 110 and a polyhedral structure 140. The light guide 110 and the polyhedral structure 140 are made of the same material. The first total internal reflection surface 111 and the second total internal reflection surface 112 are formed on the light guide 110, while the reflective surface 120, the matting surface 114, and the connecting surface 113 are formed on the polyhedral structure 140. During the formation of the optical device, the light guide 110 and the polyhedral structure 140 are bonded and fixed, thereby connecting the reflective surface 120, the matting surface 114, and the connecting surface 113 to the first total internal reflection surface 111 and the second total internal reflection surface 112, respectively. Similarly, refer to... Figure 9 As shown by the dashed line in the image, Figure 9 The example illustrates another way of dividing the light guide 110 and the polyhedral structure 140, the principle of which is the same as... Figure 8 The principle shown is the same, so it will not be repeated here.

[0058] Of course, in addition to the above methods, other methods can be used to set the reflective surface 120, the matte surface 114 and the connecting surface 113, which will not be illustrated here.

[0059] This application also provides a near-eye display device, which includes a light generator and the optical components described above; wherein, The light generated by the light generator only enters the light guide 110 at the light incident end.

[0060] In the above technical solution, by adopting the reflective surface 120 to be inclined relative to the first total internal reflection surface 111, the light incident on 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, by setting the first end and the second end of the reflective surface 120, the reflected light can be spread throughout the light guide 110, thereby achieving uniform light distribution. In addition, stray light reflected by the reflective surface 120 can be filtered out, thereby improving the optical performance of the optical device and improving the effect of the light guide 110 in achieving near-eye display.

[0061] 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 within the scope of protection of this disclosure.

[0062] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An optical device, characterized in that, include: Light guides and reflective surfaces; among which, The light guide includes a first total internal reflection surface and a second total internal reflection surface that are parallel to each other; the second total internal reflection surface has a light incident end and an exit end facing each other. The reflective surface is inclined relative to the first total internal reflective surface and is close to the light incident end; The first end of the reflective surface is located on the side of the first fully internal reflective surface that is away from the second fully internal reflective surface, and the second end of the reflective surface is located between the first fully internal reflective surface and the second fully internal reflective surface; and there is a set distance between the second end of the reflective surface and the second fully internal reflective surface. The length direction of the first total internal reflective surface is the first direction; The distance L between the endpoint of the first total internal reflective surface near the reflective surface and the second end of the reflective surface in the first direction satisfies: ;and ; Alternatively, the distance L between the endpoint of the first total internal reflective surface near the reflective surface and the second end of the reflective surface in the first direction satisfies: ； ； Alternatively, the distance L between the endpoint of the first total internal reflection surface near the reflecting surface and the second end of the reflecting surface in the first direction satisfies: ； ； Where H is the vertical distance between the second end of the reflecting surface and the second total internal reflecting surface; b is the angle between the reflecting surface and the second total internal reflecting surface; 'a' is half the angle of maximum incident angle; d is the vertical distance between the first total internal reflective surface and the second total internal reflective surface; j is a coefficient, and 50% ≤ j ≤ 1; k and l are redundant values.

2. The optical device according to claim 1, characterized in that, It also includes an matte surface, one end of which is connected to the first end of the reflective surface, and the other end is fixedly connected to the end of the first total internal reflective surface near the reflective surface, and is used to absorb light that has been reflected twice by the reflective 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 matting 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 matting surface is inclined relative to the first total internal reflection surface, and the matting surface forms an obtuse angle with the first total internal reflection surface.

5. The optical device according to any one of claims 2 to 4, characterized in that, It also includes a connecting surface, one end of which is connected to the second end of the reflective surface, and the other end of which is connected to the end of the second total internal reflective surface near the second end of the reflective surface.

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

7. The optical device according to claim 1, characterized in that, The first fully internal reflective surface is connected to the reflective surface through two or three exposed surfaces; the second fully internal reflective surface is connected to the reflective surface through two or three exposed surfaces.

8. A near-eye display device, characterized in that, Includes a light generator and an optical device as described in any one of claims 1 to 7; wherein, The light generated by the light generator enters the light guide only at the light incident end.

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