CN221079070U - Optical assembly and augmented reality display device - Google Patents

Abstract

The present application provides an optical assembly and an augmented reality display device, comprising a primary mirror configured to allow reflection of light; the secondary reflectors are arranged at intervals at the opposite ends of the primary reflector and face the primary reflector, and the secondary reflector is configured to receive light reflected by the primary reflector; the incident window is arranged at the center of the secondary reflector and aligned with the primary reflector, and is configured to allow light to be incident into a space formed by the primary reflector and the secondary reflector; and an exit window disposed in parallel with the entrance window and surrounding the primary mirror, the exit window configured to allow light to exit within a space formed by the primary mirror and the secondary mirror; the incident window is used for installing the micro-display, light rays of the micro-display are incident to the primary reflector through the incident window, are emitted through the emergent window after being reflected to the secondary reflector through the primary reflector, and the light path folding is realized through the primary reflector and the secondary reflector, so that the whole volume is effectively reduced.

Description

Optical assembly and augmented reality display device

Technical Field

The application belongs to the technical field of augmented reality display, and particularly relates to an optical assembly and augmented reality display equipment.

Background

Augmented reality (augmented reality, AR) is a technique that calculates in real time the position and angle of an image projected by a light engine system (also called projector or optomechanical) and adds the corresponding image. The augmented reality technology can realize that the virtual world is sleeved on the real world on a screen and interacted, namely, entity information (such as visual information, sound, touch and the like) which is difficult to experience in the real world time space range can be overlapped after simulated and simulated by a computer and the like, and the virtual information is applied to the real world. Since the augmented reality technology makes interaction between the virtual world and the real world possible, the method is widely applied to augmented reality display devices, such as AR glasses, capable of projecting a virtual image into human eyes to realize superposition of the virtual image and the real image.

Wherein, the core components of the AR display device mainly comprise a micro-display and an optical element. Optical elements include prisms, free-form surfaces, optical waveguides, and the like. However, the optical technical scheme is complex, and has the problems of large volume and the like.

Disclosure of Invention

The embodiment of the application aims to provide an optical assembly, an augmented reality display device and a head-mounted display device, which can solve the problems of complex optical path, large volume and the like in the prior art and effectively reduce the overall size.

In order to achieve the above object, according to a first aspect of the present application, a technical scheme is as follows: there is provided an optical assembly for use in an augmented reality display device, comprising:

a primary mirror configured to allow reflection of light;

A secondary mirror disposed at opposite ends of the primary mirror at intervals and facing the primary mirror, the secondary mirror being configured to receive light reflected from the primary mirror;

An incident window disposed at the center of the secondary mirror and aligned with the primary mirror, the incident window configured to allow light to be incident into a space formed by the primary mirror and the secondary mirror; and

An exit window disposed in parallel with the entrance window and surrounding the primary mirror, the exit window configured to allow light to exit from a space formed by the primary mirror and the secondary mirror;

The incident window is used for installing the micro-display, and light rays of the micro-display are incident to the primary reflecting mirror from the incident window, reflected to the secondary reflecting mirror from the primary reflecting mirror and then emitted out through the emergent window.

In one possible implementation, the primary mirror is any one of an inclined plane, a spherical plane, an aspherical plane, or a free-form surface; the secondary reflector is any one of an inclined plane, a spherical plane, an aspheric plane or a free curved plane, and the primary reflector and the secondary reflector are provided with reflecting materials.

In one possible implementation, the optical assembly further includes a side wall, one end of the side wall is connected to the exit window, and the opposite end of the side wall is connected to the secondary mirror, wherein an area enclosed between the primary mirror, the exit window, the side wall, the secondary mirror, and the entrance window is a solid uniform light-transmitting medium, and reflective materials of the primary mirror and the secondary mirror are disposed on a side facing away from the solid light-transmitting medium.

In one possible implementation, the optical assembly further includes a side wall, one end of the side wall is connected to the exit window, and the opposite end of the side wall is connected to the secondary mirror, wherein an area enclosed between the primary mirror, the exit window, the side wall, the secondary mirror, and the entrance window is hollow, a reflective material of the primary mirror is coated on a side facing the hollow area, and a reflective material of the secondary mirror is disposed on a side facing or facing away from the hollow area.

In one possible implementation, the lateral dimension of the primary reflector is greater than or equal to the lateral dimension of the incident window, the primary reflector is aligned with the center of the incident window, the lateral dimension of the primary reflector is greater than or equal to the lateral dimension of the micro display, and the surrounding dimensions of the primary reflector, the emergent window, the side wall, the secondary reflector and the incident window are between 1 cubic millimeter and 1 cubic centimeter.

In one possible implementation, the optical assembly further comprises a first non-transmissive layer that does not allow light to pass through, the first non-transmissive layer covering the side walls, the first non-transmissive layer being flush with the secondary mirror, the exit window, and allowing the entrance window, the exit window to leak out of the first non-transmissive layer, the exit window having a lateral dimension equal to a lateral dimension of the secondary mirror.

To achieve the above object, in a second aspect, there is provided an augmented reality display device comprising a micro display and an optical assembly as described above, wherein the micro display is provided at an entrance window.

In one possible implementation, the augmented reality display device further includes an intermediate layer positioned between the microdisplay and the entrance window to bond the microdisplay to the entrance window.

In one possible implementation, the display device further includes a back plate, the back plate is located at a side of the micro display facing away from the incident window and is electrically connected to the micro display, the back plate is used for being connected to a driving power supply, the augmented reality display device further includes a second non-transmissive layer passing through the back plate, the second non-transmissive layer fills a gap between the micro display, the back plate, the middle layer and the secondary mirror, and the second non-transmissive layer allows at least part of the back plate to leak out.

In a possible implementation, a protective layer is further included, which is arranged at the end face of the exit window, and which covers the exit window and the primary mirror.

The application has the beneficial effects that the primary reflector is configured to allow the reflected light; the secondary reflectors are arranged at intervals at the opposite ends of the primary reflector and face the primary reflector, and the secondary reflector is configured to receive light reflected by the primary reflector; an incident window disposed at the center of the secondary mirror and aligned with the primary mirror, the incident window configured to allow light to be incident into a space formed by the primary mirror and the secondary mirror; and an exit window disposed in parallel with the entrance window and surrounding the primary mirror, the exit window configured to allow light to exit within a space formed by the primary mirror and the secondary mirror; the incident window is used for installing the micro-display, and the light of the micro-display is incident to the primary reflector from the incident window, reflected to the secondary reflector from the primary reflector and then exits through the exit window. The light path folding is realized through the primary and secondary reflectors, so that the whole volume is effectively reduced, and meanwhile, the tiny volume is assembled on other equipment, so that the overlarge influence on the other equipment is not easy to cause.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of an embodiment of an optical assembly according to an embodiment of the present application;

FIG. 2 is a schematic diagram of an optical component according to another embodiment of the present application;

FIG. 3 is a schematic view of an optical component according to another embodiment of the present application;

fig. 4 is a schematic structural diagram of an embodiment of an augmented reality display device according to an embodiment of the present application;

fig. 5 is a schematic structural diagram of an embodiment of a partial enlarged view of an augmented reality display device according to an embodiment of the present application;

Fig. 6 is a schematic structural diagram of another embodiment of an augmented reality display device according to an embodiment of the present application.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are merely for convenience in describing and simplifying the description based on the orientation or positional relationship shown in the drawings, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

An optical assembly and an augmented reality display device provided by embodiments of the present application will now be described.

Referring to fig. 1, the present application provides an optical assembly 10 for use in an augmented reality display device, comprising: the primary mirror 2 is configured to allow reflection of light; the secondary mirrors 4 are disposed at intervals at opposite ends of the primary mirror 2 and face the primary mirror 2, and the secondary mirrors 4 are configured to receive light reflected from the primary mirror 2. It will be appreciated that primary mirror 2 and secondary mirror 4 may be coated with an associated reflective material to reflect light, which may be spherical, aspherical, curved, non-curved (specular), etc. in shape, for example. The entrance window 5 is arranged at the center of the secondary reflector 4 and is aligned with the primary reflector 2, i.e. the entrance window 5 and the primary reflector 2 are also aligned centrally; the entrance window 5 is configured to allow light to be incident into a space formed by the primary mirror 2 and the secondary mirror 4; and an exit window 3 arranged parallel to the entrance window 5 and surrounding the primary mirror 2, the exit window 3 being configured to allow light rays to exit from a space formed by the primary mirror 2 and the secondary mirror 4, which space may be solid or hollow.

The incident window 5 is used for mounting the micro display 6, and the light of the micro display 6 is incident to the primary reflector 2 through the incident window 5, reflected to the secondary reflector 4 by the primary reflector 2, and then exits through the exit window 3. It will be appreciated that the entrance window 5 and the exit window 3 may be solid and of the same material, e.g. the material used for the optical assembly as a whole may be a transparent or light-transmitting hard machinable material, e.g. PMMA (polymethyl methacrylate ), PC (polycarbonate, polycarbonate) plastic, resin, glass, etc., it being understood that the entrance window 5, the exit window 3 may also be understood as a virtual body, e.g. as an opening of a solid part, as long as the corresponding light entrance and light exit is fulfilled. The optical assembly 10 may be a cylindrical, prismatic, or truncated cone, etc. regular shape, or irregular shape, etc. and may have opposite parallel first and second ends 11 and 12.

It is understood that the primary mirror 2 may be any one of an inclined surface, a spherical surface, an aspherical surface, or a free-form surface; wherein the primary reflecting mirror 2 and the emergent window 3 are arranged in a non-coplanar manner, the secondary reflecting mirror 4 can be any one of an inclined plane, a spherical plane, an aspherical plane or a free curved plane, and the secondary reflecting mirror 4 and the incident window 5 are arranged in a non-coplanar manner; the primary mirror 2 and the secondary mirror 4 may be formed by injection molding, turning, photolithography, or the like. The schematic diagram of the present application is only a schematic diagram of cross section reference, so that the primary reflecting mirror 2 is arc-shaped in the illustration, and the secondary reflecting mirror 4 can be an aspheric inclined plane, and can be arc-shaped.

The Micro display 6 may be a Micro-LED (Micro Light-Emitting Diode), uLED (Micro Light-Emitting Diode), micro-oled (Micro Organic Light-Emitting Diode), LCoS (Liquid Crystal On Silicon ), LCD (Liquid CRYSTAL DISPLAY, liquid crystal display), DMD (Digital Micromirror Device )/DLP (DIGITAL LIGHT Processing) or LBS (Laser Beam Scanning ), or the like, or any combination of these technologies. The micro-display 6 may provide an image source such as text, video, information cues, and the like.

After entering through the entrance window 5, the light L is reflected by the primary mirror 2 to the secondary mirror 4 and then exits through the exit window 3. The light transmission can be unaffected in this folded light path. The light path folding is realized through the primary and secondary reflectors, so that the whole volume is effectively reduced, and meanwhile, the tiny volume is assembled on other equipment, so that the tiny volume is not easy to cause excessive influence on the other equipment (such as the appearance or structure of the equipment before being changed, etc.).

In some embodiments, the reflective material coated on primary mirror 2 and secondary mirror 4 may be a reflective material such as a metal or metal alloy, for example, aluminum, silver, or a mixture of aluminum and silver, or the like.

In some embodiments, referring to fig. 1, the optical component set 10 further includes a side wall 1, one end of the side wall 1 is connected to the exit window 3, and the opposite end of the side wall 1 is connected to the secondary reflector 4, where the primary reflector 2, the exit window 3, the side wall 1, the secondary reflector 4, and the entrance window 5 are surrounded by a solid uniform transparent (or transparent) medium, such as transparent PMMA (polymethyl methacrylate ), PC (polycarbonate, polycarbonate) plastic, plexiglass, and the reflective material of the primary reflector 2 and the secondary reflector 4 is disposed on a side facing away from the solid transparent medium. It will be appreciated that the primary mirror 2 may be formed by recessing a relatively solid transparent substrate, for example, the shapes of the primary mirror 2 and the secondary mirror 4 may be formed by cutting, injection molding, or the like, and then the reflective material may be directly disposed on the surfaces thereof by coating or filming, or the like, for example, in fig. 1, the primary mirror 2 is disposed in a solid recession, and the reflective material is disposed toward the plane of the exit window 3, where a solid uniform transparent or transparent medium may ensure that the light L propagates (reflects) in a uniform same medium without refraction or dispersion, or the like, and may further ensure that the entire optical assembly 10 is more firm.

In some embodiments, referring to fig. 2, the optical assembly 10 further includes a side wall 1, one end of the side wall 1 is connected to the exit window 3, and the opposite end of the side wall 1 is connected to the secondary mirror 4, where an area enclosed between the primary mirror 2, the exit window 3, the side wall 1, the secondary mirror 4, and the entrance window 5 is hollow, the reflective material of the primary mirror 2 is disposed on a side facing the hollow area, and the reflective material of the secondary mirror 4 is disposed on a side facing or facing away from the hollow area. It will be appreciated that the solid primary mirror 2 and the exit window 3 may be formed by injection molding or turning, the reflective material may be subsequently provided on the surface of the primary mirror 2 by a coating or plating process, and then the solid secondary mirror 4 may be formed by a similar process to the solid secondary mirror 4 by a side wall 1, the reflective material may be subsequently provided on the front side or the rear side of the secondary mirror 4 by a coating or plating process, and finally the two integral parts of the reflective material are fixed, for example, by adhesive connection, to form the hollow optical assembly. For example, in fig. 2, primary mirror 2 is positioned within the hollow region, and the reflective material is also oriented toward the hollow region (i.e., facing the entrance window); the hollow arrangement allows to reduce the weight of the optical component 1, further facilitating its assembly to other wearable devices, but of course also allows to reduce the material, and on the other hand also improves the overall production process from another point of view.

The transverse dimension of the primary reflector 2 is larger than or equal to the transverse dimension of the incident window 5, the centers of the primary reflector 2 and the incident window 5 are aligned, the transverse dimension of the primary reflector 2 is larger than or equal to the transverse dimension of the micro display 6, and the surrounding dimensions among the primary reflector 2, the emergent window 3, the side wall 1, the secondary reflector 4 and the incident window 5 are between 1 cubic millimeter and 1 cubic centimeter. The size of the device is relatively small in visual sense, and the device is easy to integrate into various other devices, such as glasses and the like, without affecting the appearance or large-area structure of the original device, and has a good adaptation space.

In some embodiments, referring to fig. 1, 2 and 4 in combination, the lateral dimension of primary mirror 2 is equal to or greater than the lateral dimension of entrance window 5, and primary mirror 2 is aligned with the center of entrance window 5, and the lateral dimension of primary mirror 2 is equal to or greater than the lateral dimension of microdisplay 6. I.e. it is satisfied that the light L coming from the entrance window 5 can be totally reflected onto the primary mirror 2, it is also acceptable that the light coming in from the entrance window 5 directly coming out of the exit window 3 overlaps with the light coming in from the entrance window 5 through the primary mirror 2 and the secondary mirror directly coming out of the exit window 3, provided that the primary mirror 2 has a lateral dimension smaller than the entrance window 5 (or the mounted micro-display 6, e.g. fig. 4), which affects the final imaging, if such an effect is acceptable, the lateral dimension of the primary mirror 2 is suitably smaller than the lateral dimension of the micro-display 6.

The microdisplay 6 has a resolution of no less than 2 minutes of arc per pixel of the wearer's field of view and a pixel-to-pixel spacing of no more than 5 microns.

In some embodiments, microdisplay 6 can emit an array of light pixels, in some embodiments, with a pixel-to-pixel spacing of no more than 4 microns, and the magnification of the projected image of microdisplay 6 is no less than 2.5, e.g., the image source is magnified 3, 4, or 10 times before reaching the retina, ensuring that the contents of the projected image are clearly visible, as measured from the projected image of microdisplay 6 to the retina of the wearer. The projected image of the micro-display 6 covers at least an 8 ° field angle of view of the wearer, for example 8 °, 15 °, 20 °, etc.; the device does not occupy the field angle of about 60 degrees of the whole human eyes, so that the wearer can see the projected image and the image in the real situation.

In some embodiments, in combination with figures 3, 5 and 6, the optical assembly further comprises a first non-transmissive layer 71 which does not allow light to pass through, the first non-transmissive layer 71 covering the shielding sidewall 1, allowing only the entrance window 5, the exit window 3 to escape with respect to the first non-transmissive layer 71. The first opaque layer 71 may be formed integrally with the sidewall 1, for example, the outside of the sidewall 1 is opaque; alternatively, the first opaque layer 71 may be disposed on the sidewall 1 by a separate application such as coating, plating, or other encapsulation. The first opaque layer 71 may be black or other opaque material, and may be black epoxy or black silicone rubber, for example. The first non-transmissive layer 71 is flush with the secondary mirror 4, the exit window 3 and allows the entrance window 5, the exit window 3 to leak out with respect to the first non-transmissive layer 71, ensuring that the entire circumferential side wall 1 is omnidirectionally wrapped and does not allow light rays L to exit from the side wall 1, reducing the loss of light eventually exiting the exit window 3, of course the lateral dimension of the entrance window exit window 3 being equal to the lateral dimension of the secondary mirror 4, facilitating the formation of a regular shape, facilitating the adaptation of subsequent packages or other devices. Of course, the non-reflecting surface of the secondary mirror 4 may also be covered by the first opaque layer 71 in order to achieve an omnidirectional shielding. Fig. 3 is for convenience only in terms of an example of the first non-transmissive layer 71, and the first non-transmissive layer 71 may be a coating or material such as black epoxy, black silicone rubber, carbon black, nickel black, black chrome or tower of Hanoi black, or may be an opaque sealing sleeve, or the like.

Referring to fig. 4-6 in combination, the present application also provides an augmented reality display device comprising a micro-display 6 and an optical assembly 10 as described above, wherein the micro-display 6 is disposed at the entrance window 5, and the micro-display 6 can provide an image source. The augmented reality display device may be applied in head-mounted devices (e.g., smart glasses, sunglasses, sports glasses, myopia glasses, etc.), heads-up displays, or other devices in the optical or display field. The description of the optical assembly 10 and the micro display 6 can be referred to the above embodiments and will not be repeated here.

In some embodiments, the augmented reality display device further comprises an intermediate layer 62, the intermediate layer 62 being located between the microdisplay 6 and the entrance window 5 to bond the microdisplay 6 to the entrance window 5. The intermediate layer may be transparent optical glue and the intermediate layer 62 may serve to fix the micro-display 6 to the optical assembly 1, which also does not cause optical losses. Of course, if the press fit between the microdisplay 6 and the entrance window 5 is sufficiently tight, the intermediate layer may not be present. In some embodiments, the intermediate layer may also be air or the like, and the microdisplay 6 may be secured by an external package or sleeve.

In some embodiments, the micro-display device further includes a back plate 61, where the back plate 61 is located on a side of the micro-display device 6 facing away from the incident window 5 and is electrically connected to the micro-display device 6, and the back plate 61 may be a driving board such as a circuit board, which may be rigid or flexible. The back plate 61 is used for connecting a driving power supply to provide electric driving for the micro display 61. The back plate 61 may be larger than or equal to the microdisplay 6 (e.g., light emitting device), although the size of the back plate 61 is preferably matched to the overall size to ensure a more regular shape or to facilitate subsequent packaging.

In some embodiments, the augmented reality display device further comprises a second non-transmissive layer 72, the second non-transmissive layer 72 filling the gap between the micro-display 6, the back plate 61, the intermediate layer 62, the secondary mirror 4, the second non-transmissive layer 72 allowing at least part of the back plate 61 to leak out to facilitate connection to external circuitry (e.g. drive or power supply, etc.). The second non-transmissive layer 72 can realize integral positioning and packaging of the optical assembly 10 and the microdisplay 6, the back plate 61, and the intermediate layer 62, and reduce the probability of positional misalignment of the components. Of course, the micro display 6 and the intermediate layer 62 may be appropriately packaged to prevent light leakage. The second non-transmissive layer 72 may be the same material as the first non-transmissive layer 71, and may be, for example, black epoxy, black silicone rubber, or the like. It is understood that the first non-transmissive layer 71 and the second non-transmissive layer 72 may be integral, for example, the non-transmissive layer 71 may not be disposed in the optical component 10 first, but the non-transmissive layer may be disposed directly in the augmented reality display device 100, i.e., it may be integrally formed.

In some embodiments, the augmented reality display device 100 further comprises a protective layer 8, the protective layer 8 being arranged at an end face of the exit window 3, and the protective layer 8 covering the exit window 3 and the primary mirror 2. It can be appreciated that the protection layer 8 may be fixed by, for example, gluing, and the protection layer 8 may be made of a light-transmitting material, which may not change the propagation path of the original light, and may protect the exit window 3 and the primary reflector 2, reduce abrasion to the exit window and reduce impurities such as dust entering the primary reflector 2 to affect the reflection efficiency of the primary reflector.

The foregoing description of the preferred embodiments of the application is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the application.

Claims (13)

1. An optical assembly (10) for use in an augmented reality display device, comprising:

a primary mirror (2) configured to allow reflected light rays;

A secondary mirror (4) disposed at an opposite end of the primary mirror (2) at intervals and directed toward the primary mirror (2), the secondary mirror (4) being configured to receive light reflected from the primary mirror (2);

An entrance window (5) disposed at the center of the secondary mirror (4) and aligned with the primary mirror (2), the entrance window (5) being configured to allow light to be incident into a space formed by the primary mirror (2) and the secondary mirror (4); and

-An exit window (3) arranged parallel to the entrance window (5) and surrounding the primary mirror (2), the exit window (3) being configured to allow light rays to exit within a space formed by the primary mirror (2) and the secondary mirror (4);

The incidence window (5) is used for installing a micro display (6), and light rays of the micro display (6) are incident to the primary reflecting mirror (2) through the incidence window (5), reflected to the secondary reflecting mirror (4) through the primary reflecting mirror (2) and then emitted through the emergent window (3).

2. The optical assembly (10) according to claim 1, wherein the primary mirror (2) is any one of an inclined surface, a spherical surface, an aspherical surface or a free-form surface; the secondary reflector (4) is any one of an inclined plane, a spherical plane, an aspheric plane or a free curved plane, and the primary reflector (2) and the secondary reflector (4) are provided with reflecting materials which comprise metal.

3. The optical assembly (10) according to claim 2, wherein the optical assembly (10) further comprises a side wall (1), one end of the side wall (1) is connected with the exit window (3), the opposite end of the side wall (1) is connected with the secondary mirror (4), wherein the primary mirror (2), the exit window (3), the side wall (1), the secondary mirror (4) and the entrance window (5) are surrounded by a solid uniform light-transmitting medium, and the reflective materials of the primary mirror (2) and the secondary mirror (4) are arranged on one side facing away from the solid light-transmitting medium.

4. The optical assembly (10) according to claim 2, wherein the optical assembly (10) further comprises a side wall (1), one end of the side wall (1) is connected with the exit window (3), the opposite end of the side wall (1) is connected with the secondary reflector (4), wherein an area enclosed between the primary reflector (2), the exit window (3), the side wall (1), the secondary reflector (4) and the entrance window (5) is hollow, the reflective material of the primary reflector (2) is coated on one side facing the hollow area, and the reflective material of the secondary reflector (4) is arranged on one side facing or departing from the hollow area.

5. The optical assembly (10) according to claim 3 or 4, wherein the lateral dimension of the primary mirror (2) is greater than or equal to the lateral dimension of the entrance window (5), the primary mirror (2) and the entrance window (5) are aligned in the center, the lateral dimension of the primary mirror (2) is greater than or equal to the lateral dimension of the micro-display (6), and the enclosure dimensions of the primary mirror (2), the exit window (3), the side wall (1), the secondary mirror (4) and the entrance window (5) are between 1 cubic millimeter and 1 cubic centimeter.

6. An optical assembly (10) as claimed in claim 3 or 4, characterized in that the optical assembly further comprises a first non-transmissive layer (71) which does not allow light to pass through, the first non-transmissive layer (71) covering the side wall (1), the first non-transmissive layer (71) being flush with the secondary mirror (4), the exit window (3) and allowing the entrance window (5), the exit window (3) to leak out with respect to the first non-transmissive layer (71), the exit window (3) having a lateral dimension equal to the lateral dimension of the secondary mirror (4).

7. The optical assembly (10) of claim 6, wherein the first non-transmissive layer (71) comprises any of a black epoxy, a black silicone rubber, carbon black, nickel black, black chrome, or tower of Hanoi black coating.

8. An augmented reality display device (100) comprising a micro-display (6) and an optical assembly (10) according to any one of claims 1 to 7, wherein the micro-display (6) is provided to the entrance window (5) for projecting an image.

9. The augmented reality display device (100) according to claim 8, further comprising an intermediate layer (62), the intermediate layer (62) being located between the micro-display (6) and the entrance window (5) to connect the micro-display (6) and the entrance window (5).

10. The augmented reality display device (100) according to claim 9, further comprising a back plate (61), the back plate (61) being located at a side of the micro display (6) facing away from the entrance window (5) and being electrically connected to the micro display (6), the back plate (61) being adapted to be connected to a driving power source, the augmented reality display device further comprising a second non-transmissive layer (72), the second non-transmissive layer (72) filling a gap between the micro display (6), the back plate (61), the intermediate layer (62), the secondary mirror (4), the second non-transmissive layer (72) allowing at least part of the back plate (61) to leak out.

11. The augmented reality display device (100) according to claim 8, characterized in that it further comprises a protective layer (8), the protective layer (8) being arranged at an end face of the exit window (3), and the protective layer (8) covering the exit window (3) and the primary mirror (2).

12. The augmented reality display device (100) of claim 8, wherein the micro-display (6) has a resolution of no less than 2 arc minutes per pixel of the wearer's field of view, and the micro-display has a pixel-to-pixel pitch of no more than 5 microns.

13. The augmented reality display device (100) according to claim 8, characterized in that the projected image of the micro display (6) covers at least an 8 ° field angle of view of the wearer, the magnification of the projected image being not less than 2.5.