Optical waveguide device and AR display device

Abstract

The present invention discloses an optical waveguide device, comprising a light coupling unit and a plurality of waveguide units; the plurality of waveguide units are sequentially arranged along the outgoing light path of the light coupling unit; wherein, the surface of each waveguide unit for reflecting the projection light beam is provided with a plurality of discretely distributed reflective elements; and the farther the waveguide unit is from the light coupling unit, the greater the proportion of the total area of ​​the reflective elements on the corresponding surface to the surface area of ​​the waveguide unit, so that the reflectivity of each waveguide unit to the projection light beam reaches the target reflectivity; the present application only arranges a plurality of uniformly distributed small-area reflective elements on the surface of the optical waveguide unit; and the farther from the light coupling unit, the greater the proportion of the area of ​​the reflective elements, so that the optical waveguide unit simplifies the preparation process of the optical waveguide device and reduces the device cost on the basis of ensuring the uniformity of the projection light beam outcoupling. The present application also provides an AR display device having the above-mentioned beneficial effects.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, and in particular to an optical waveguide device and an AR display device. Background Art

[0002] Augmented Reality (AR) is a technology that superimposes virtual images on real scenes. People at home and abroad are paying attention to and studying it, and corresponding products have appeared. The augmented reality display device combines the virtual images generated by the computer with the real scene and displays it to the user, so that the user can receive virtual information while also observing the real scene, thus achieving a sensory experience beyond reality. Therefore, this technology is applied to all walks of life and is becoming a research hotspot.

[0003] There are many technologies for realizing AR at present. Generally speaking, in order to realize AR glasses with a large field of view, geometric array optical waveguides are used. In order to make the image light transmitted in the waveguide evenly incident on the human eye, the dielectric film on each optical waveguide unit needs to be designed separately, so that each optical waveguide unit is plated with a dielectric film with different reflectivity. This optical waveguide unit brings inconvenience to the production and processing of the optical waveguide unit, and also greatly increases the production cost. Summary of the invention

[0004] The purpose of the present invention is to provide an optical waveguide device and an AR display device, which solves the problem that the reflectivity of each waveguide unit is different, resulting in high production cost of the waveguide unit.

[0005] In order to solve the above technical problems, the present invention provides an optical waveguide device, comprising a light coupling unit and a plurality of waveguide units; the plurality of waveguide units are arranged in sequence along the outgoing light path of the light coupling unit;

[0006] A surface of each waveguide unit for reflecting the projection light beam is provided with a plurality of discretely distributed reflective elements; and the farther the waveguide unit is from the light coupling unit, the greater the proportion of the total area of ​​the reflective elements on the corresponding surface to the surface area of ​​the waveguide unit, so that the reflectivity of each waveguide unit to the projection light beam reaches the target reflectivity.

[0007] In an optional embodiment of the present application, the multiple reflective elements on the surface of each of the waveguide units are evenly distributed.

[0008] In an optional embodiment of the present application, the reflective element on the waveguide unit is any one or more film layers of a circular reflective element, an elliptical reflective element, a square reflective element, and a regular polygonal reflective element.

[0009] In an optional embodiment of the present application, the diameter of each reflective element distributed in a dot matrix on the waveguide unit is no more than 4 mm.

[0010] In an optional embodiment of the present application, the reflective element is a metal film or a reflective grating.

[0011] In an optional embodiment of the present application, the reflective elements on each of the waveguide units are distributed in an array.

[0012] In an optional embodiment of the present application, the reflective element is a film layer formed on the surface of each waveguide unit using different mask plates;

[0013] Wherein, the mask plate is provided with evenly distributed open through holes set according to the target reflectivity of each of the waveguide units.

[0014] In an optional embodiment of the present application, each of the waveguide units is used to reflect the surface of the projection light beam transmitted by the light coupling unit, and is also provided with an anti-reflection dielectric film, and the reflective elements are uniformly arranged on the surface of the anti-reflection dielectric film.

[0015] The present application also provides an AR display device, comprising the optical waveguide device as described in any one of the above items, and a projection device for emitting a projection light beam to an incident surface of a light coupling unit in the optical waveguide device.

[0016] The optical waveguide device provided by the present invention comprises a light coupling unit and a plurality of waveguide units; the plurality of waveguide units are sequentially arranged along the outgoing light path of the light coupling unit; a surface of each waveguide unit for reflecting a projection light beam is provided with a plurality of discretely distributed reflective elements; the farther the waveguide unit is from the light coupling unit, the greater the proportion of the total area of ​​the reflective elements on the corresponding surface to the surface area of ​​the waveguide unit, so that the reflectivity of each waveguide unit to the projection light beam reaches a target reflectivity;

[0017] In this embodiment, when a reflective element is set on the surface of each optical waveguide unit, compared with the method of directly setting a reflective element on the entire surface of the optical waveguide unit in the prior art, the present application only sets a plurality of reflective elements with a small area on the surface of the waveguide unit, and the plurality of reflective elements are discretely distributed on the surface of the optical waveguide unit; in addition, in each optical waveguide unit, the farther away from the light coupling-in unit, the greater the area ratio occupied by the reflective element on the surface of the optical waveguide unit. It can be seen that the reflectivity of the reflective elements on each waveguide unit in the present application can be exactly the same, and when actually forming the reflective elements, it is not necessary to form a reflective element with a reflectivity for each waveguide unit. It is only necessary to control the different area ratios of the reflective elements, so that the reflectivity of each optical waveguide unit can be different according to the requirements of projection uniformity, so that the optical waveguide unit simplifies the preparation process of the optical waveguide device and reduces the device cost on the basis of ensuring the uniformity of the projection light beam coupling-out.

[0018] The present application also provides an AR display device having the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic diagram of the structure of an optical waveguide device provided in an embodiment of the present application;

[0021] Figure 2 A schematic diagram of the arrangement of reflective elements on a waveguide unit provided in an embodiment of the present application;

[0022] Figure 3 Another schematic diagram of the three-dimensional structure of the waveguide device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] like Figures 1 to 3 As shown, Figure 1 A schematic top view of an optical waveguide device provided in an embodiment of the present application, Figure 2A schematic diagram of the three-dimensional structure of a waveguide device provided in an embodiment of the present application; Figure 3 Another schematic diagram of the three-dimensional structure of the waveguide device provided in the embodiment of the present application; the optical waveguide device may include:

[0025] A light coupling unit 1 and a plurality of waveguide units 2; the plurality of waveguide units 2 are sequentially arranged along an outgoing light path of the light coupling unit 1;

[0026] Specifically, in actual application, the projection device first projects a projection light beam to the light coupling unit 1. The projection light beam is transmitted in the light coupling unit 1 and emitted to the first waveguide unit 2 closest to the light coupling unit 1. The first waveguide unit reflects part of the incident projection light beam into the human eye, and transmits part of it to the second waveguide unit 2 closest to the first waveguide unit 2. The second waveguide unit 2 also reflects part of the incident projection light beam into the human eye and transmits part of it to the third waveguide unit 2. And so on. Each waveguide unit 2 reflects part of the projection light beam in turn, and the human eye sees the projection picture through the light reflected by each waveguide unit 2.

[0027] like Figure 1 and Figure 2 As shown, the light coupling unit 1 and each waveguide unit 2 and the adjacent waveguide units 2 can be glued and connected in sequence to form an integral plate-shaped light guide element, and the light coupling unit 1 and the waveguide unit 2 have the same refractive index. A reflective element 4 with a relatively small area is arranged on the reflective interface 3 between the light coupling unit 1 and the waveguide unit 2, and the reflective element 4 can reflect the incident light beam; similarly, the interface between the waveguide units 2 is also provided with a reflective element 4.

[0028] like Figure 3 As shown, in actual application, the light coupling unit 1 and the waveguide unit 2 and the waveguide units 2 may not be glued together, but a certain gap may be left between them, that is, a certain distance is pulled apart along the direction perpendicular to the incident light beam to the human eye, and the surfaces facing the light coupling unit 1 and the waveguide unit 2 and the surfaces facing adjacent waveguide units 2 are parallel to each other.

[0029] based on Figure 1 It can be seen that in order to make the projection image viewed by the human eye more uniform in brightness, it is necessary to require that the energy of the reflected light reflected by each waveguide unit 2 into the human eye is roughly the same. Therefore, it is also required that the reflectivity of the light beam of each waveguide unit 2 from near to far distances between the waveguide unit 2 and the light coupling unit 1 needs to be increased one by one; and the reflective surface 3 is the surface of the waveguide unit 2 that receives the incident projection light beam.

[0030] In conventional optical waveguide devices, a reflective film covering the entire surface needs to be set for the reflective surface of each waveguide unit, and the reflective film of each waveguide unit has a different reflectivity, so that the reflectivity of each waveguide unit meets the requirements of the brightness of the projection screen. However, this setting method makes the design of the reflective film too complicated. In the actual production process, when preparing the reflective film for each waveguide unit, the preparation process also needs to be adjusted for different waveguide units, which makes the process of preparing the reflective film more complicated, and further increases the use cost of the optical waveguide device.

[0031] Therefore, another method of setting the reflective element is provided in the present application. Figure 2 and Figure 3 As shown, in this embodiment, a plurality of discretely distributed reflective elements 4 are provided on the reflective surface 3 of each waveguide unit 2 for reflecting the projection light beam transmitted through the light coupling unit 1; the farther the waveguide unit 2 is from the light coupling unit 1, the greater the proportion of the total area of ​​each reflective element 4 on the corresponding reflective surface 3 to the area of ​​the reflective surface 3 of the waveguide unit 2, so that the reflectivity of each waveguide unit 2 to the projection light beam reaches the target reflectivity.

[0032] That is to say, in the present application, the reflective element 4 is set on the waveguide unit 2, and a plurality of discretely distributed small-area reflective elements 4 with the same reflectivity are set on the reflective surface, and the reflectivity of the entire waveguide unit 2 is changed by changing the area ratio of the reflective element 4.

[0033] Optionally, a plurality of reflective elements 4 on the same waveguide unit 2 may be evenly distributed on the surface of the waveguide unit 2 , thereby making the light reflected from the surface of the waveguide unit 2 uniform.

[0034] To sum up, compared with the prior art in which each waveguide unit adopts a reflective film with different reflectivity, the reflective element in the present application can adopt a reflective film layer with the same reflectivity, and the reflectivity of the waveguide units is made different only by the area ratio of the reflective element. There is no need to design a separate reflective film for each waveguide unit, which greatly reduces the difficulty in designing and preparing the reflective film.

[0035] Optionally, the area ratio of the reflective element of each waveguide unit can be controlled by combining the density and area size of the reflective element, which will not be described in detail.

[0036] In an optional embodiment of the present application, the target reflectivity of each waveguide unit 2 may specifically satisfy: Among them, k i is the target reflectivity of the i-th waveguide unit from the nearest to the light coupling unit, and N is the total number of waveguide units.

[0037] Based on the target reflectivity, the reflectivity and area ratio of each reflective element 4 on the waveguide unit 2 can be set.

[0038] In an optional embodiment of the present application, the shape of each reflective element 4 is not specifically limited in the present application, and can be a square, triangle, ellipse, circle or regular polygon, etc. Of course, in practical applications, reflective elements with central symmetric shapes should be used as much as possible.

[0039] It should be noted that in practical applications, a variety of reflective elements 4 of different shapes may be arranged alternately, as long as the uniformity of distribution of the reflective elements 4 on the reflective surface of the entire waveguide unit 2 can be ensured.

[0040] In an optional embodiment of the present application, the diameter of each reflective element 4 may be no greater than 4 mm. The recognition degree of the human eye is between 4 mm and 6 mm. By setting the size of the reflective element to be lower than the range that the human eye can recognize, the human eye can be prevented from recognizing the discretely distributed non-reflective elements on the waveguide unit 2, thereby improving the visual effect of the projection picture.

[0041] Similarly, the size of the reflective elements on the entire waveguide unit 2 may not be completely uniform, and reflective elements 4 of multiple different sizes may be arranged alternately. For example, an isosceles triangle reflective element may be arranged at the center of three circular reflective elements that are symmetrically distributed around the three centers, and so on. This is not limited in the present application.

[0042] Of course, in the present application, each waveguide unit may also use a reflective element with a completely uniform shape and size. Figure 2 and Figure 3 As shown, all circular reflective elements are used, and the reflective elements are distributed in an array.

[0043] When actually preparing the reflective element, various preparation processes may be used, such as electroplating and stamping, or chemical etching. Specifically, when forming the reflective element 4 on the surface of each waveguide unit 2, a corresponding mask plate may be designed for each waveguide unit 2 according to the target reflectivity, an opening through hole may be set on each mask plate, and then the mask plate may be covered on the waveguide unit 2, and the reflective element 4 may be formed at the position of the waveguide unit 2 corresponding to the opening through hole.

[0044] In addition, the material of the reflective element 4 is more preferably a metal reflective film with better reflective effect, such as a metal copper film or a metal aluminum film; it can also be a reflective grating or other optical elements that can deflect the direction of light transmission, and this is not specifically limited in the present application.

[0045] In the present application, a plurality of discrete and evenly distributed reflective elements are arranged on the surface of the waveguide unit and each waveguide unit, and the area proportion of the reflective elements increases one by one, thereby increasing the reflectivity of each waveguide unit to the projection light beam one by one; accordingly, the effect of uniform reflection of the projection light beam by the plurality of waveguide units is achieved. When each waveguide unit forms a reflective element, it is not necessary to arrange a reflective film layer with different reflectivity for each waveguide unit 2, which reduces the coating complexity of the reflective element layer on the waveguide unit to a certain extent, thereby reducing the cost of the optical waveguide device.

[0046] In another optional embodiment of the present application, an anti-reflection dielectric film is further provided on each waveguide unit.

[0047] It should be noted that when the optical waveguide device is used in an augmented reality device, it is necessary to superimpose a real virtual projection image on the real image. Therefore, the light of the real scene in the environment needs to be transmitted through the waveguide unit to enter the human eye. Therefore, in order to observe the scene in the environment more clearly, an anti-reflection dielectric film can be set on the surface of the waveguide unit 2.

[0048] Optionally, the waveguide unit 2 is first provided with an anti-reflection dielectric film, and then a plurality of reflective elements 4 are evenly distributed on the surface of the anti-reflection dielectric film.

[0049] The present application also provides an embodiment of an AR display device, which includes the optical waveguide device in any of the above embodiments, and a projection device for transmitting a projection light beam to a light coupling unit in the optical waveguide device.

[0050] The optical waveguide device used in the AR display device used in the present application adopts a plurality of discrete and uniformly distributed reflective elements as the reflective elements in each waveguide unit, and the reflectivity of each waveguide unit reaches the target reflectivity by controlling the area ratio of the reflective elements on each waveguide unit, thereby greatly reducing the coating cost of the reflective elements of each waveguide unit, thereby reducing the cost of the entire AR display device.

[0051] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment that includes a series of elements are inherent to the elements. In the absence of more restrictions, the elements limited by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or equipment that includes the elements. In addition, the above-mentioned technical solution provided in the embodiment of the present application is consistent with the corresponding technical solution in the prior art in principle, and the part is not described in detail, so as not to repeat too much.

[0052] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. An optical waveguide device, characterized in that: It comprises a light coupling unit and a plurality of waveguide units; the plurality of waveguide units are sequentially arranged along the outgoing light path of the light coupling unit; A surface of each waveguide unit for reflecting the projection light beam is provided with a plurality of discretely distributed reflective elements; and the farther the waveguide unit is from the light coupling unit, the greater the proportion of the total area of ​​the reflective elements on the corresponding surface to the surface area of ​​the waveguide unit, so that the reflectivity of each waveguide unit to the projection light beam reaches the target reflectivity.

2. The optical waveguide device according to claim 1, wherein The multiple reflective elements on the surface of each waveguide unit are evenly distributed.

3. The optical waveguide device according to claim 1, wherein The reflective element on the waveguide unit is any one or more film layers of a circular reflective element, an elliptical reflective element and a regular polygonal reflective element.

4. The optical waveguide device according to claim 3, wherein: The diameter of each of the reflective elements on the waveguide unit is no greater than 4 mm.

5. The optical waveguide device according to claim 1, wherein The reflective element is a metal film or a reflective grating.

6. The optical waveguide device according to claim 1, wherein The reflective elements on each of the waveguide units are distributed in an array.

7. The optical waveguide device according to claim 1, wherein: The reflective element is a film layer formed on the surface of each waveguide unit using different mask plates; Wherein, the mask plate is provided with an opening through hole set according to the target reflectivity of each of the waveguide units.

8. The optical waveguide device according to claim 1, wherein Each of the waveguide units is used for reflecting the surface of the projection light beam conducted by the light coupling unit, and is also provided with an anti-reflection medium film, and the reflective elements are uniformly arranged on the surface of the anti-reflection medium film.

9. An AR display device, characterized in that: The optical waveguide device comprises the optical waveguide device according to any one of claims 1 to 8, and a projection device for emitting a projection light beam to an incident surface of a light coupling unit in the optical waveguide device.

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