Micro-projection light engine and near-eye display equipment

Abstract

The utility model provides a micro-projection light engine and near-to-eye display equipment. The micro-projection light engine comprises a plurality of display screens; and the color combining device is provided with a plurality of light incident surfaces and a light emergent surface, the plurality of light incident surfaces are in one-to-one correspondence with the plurality of display screens, and the color combining device is configured to couple light rays. The at least one light extinction part is arranged at the light incident surface, and the light extinction part is configured to block reflection and propagation of light rays; and the projection lens is arranged at the light emitting surface, and the projection lens is configured to receive the light coupled by the color combination device. The micro-projection light engine can reduce the generation of stray light.

Description

Technical Field

[0001] The utility model relates to the technical field of near-eye display, and in particular to a micro-projection light engine and a near-eye display device. Background Art

[0002] Micro-projection light engines are key components in optical waveguide near-eye display devices such as AR glasses. Their size and image quality determine the quality of the user experience. Micro-LED light engines use Micro-LED displays as the light source for the entire light engine, offering advantages such as high brightness, high contrast, and miniaturization. To achieve color projection, current full-color Micro-LED light engines use three panels to emit red, green, and blue light respectively, which are then projected through a color combiner and optical lens to create a color image. To achieve ultra-miniaturization of Micro-LED light engines, the key component, the color combiner, must first be miniaturized. This causes the light emitted by the screen to be fully emitted from the sides of the color combiner, which ultimately forms stray light and affects display quality. Utility Model Content

[0003] Embodiments of the present application provide a micro-projection light engine and a near-eye display device, wherein the micro-projection light engine can reduce the generation of stray light.

[0004] The present invention provides a micro-projection light engine, comprising:

[0005] Multiple displays;

[0006] A color combining device has multiple light incident surfaces and light emitting surfaces, the multiple light incident surfaces correspond one-to-one to the multiple display screens, and the color combining device is configured to couple light.

[0007] at least one light-removing element, the light-removing element being disposed at the light incident surface and configured to block reflection and propagation of light;

[0008] A projection lens is disposed at the light-emitting surface and is configured to receive the light coupled by the color combining device.

[0009] An embodiment of the present application also provides a near-eye display device, comprising the above-mentioned micro-projection light engine.

[0010] The micro-projection light engine and near-eye display device provided in embodiments of the present application include multiple display screens, a color combining device, at least one light-exiting element, and a projection lens. The color combining device has multiple light-entry surfaces and light-exiting surfaces, each corresponding to a plurality of display screens. The color combining device is configured to couple light. The light-exiting element is provided on the color combining device, positioned at the light-entry surface of the color combining device to block the reflected propagation of light, thereby preventing the reflected light from entering the projection lens, ultimately reducing or even eliminating stray light. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] To more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present application. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0012] Figure 1 This is a schematic diagram of the first structure of the micro-projection light engine provided in an embodiment of the present application.

[0013] Figure 2 This is a schematic diagram of the first structure of a micro-projection light engine in the prior art.

[0014] Figure 3 Schematic diagram of stray light and display screen in the prior art.

[0015] Figure 4 A schematic diagram of a display screen provided in an embodiment of the present application.

[0016] Figure 5 A schematic diagram of the structure of the color combining device provided in an embodiment of the present application.

[0017] Figure 6 This is a schematic diagram of the second structure of a micro-projection light engine in the prior art.

[0018] Figure 7 This is a schematic diagram of the second structure of the micro-projection light engine provided in an embodiment of the present application.

[0019] Figure 8 This is a schematic diagram of the third structure of a micro-projection light engine in the prior art.

[0020] Figure 9 This is a schematic diagram of the third structure of the micro-projection light engine provided in an embodiment of the present application.

[0021] Figure 10 This is a fourth structural diagram of the micro-projection light engine provided in an embodiment of the present application.

[0022] Figure 11This is a fifth structural diagram of the micro-projection light engine provided in an embodiment of the present application.

[0023] Figure 12 This is a sixth structural diagram of the micro-projection light engine provided in an embodiment of the present application. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0025] See also Figure 1 , Figure 1 This is a schematic diagram of the first structure of a micro-projection light engine provided in an embodiment of the present application. This embodiment of the present application provides a micro-projection light engine 100 and a near-eye display device. The micro-projection light engine 100 includes multiple display screens 10, a color combining device 20, at least one extinction element 50, and a projection lens 60.

[0026] The color combining device 20 has multiple light entrance surfaces 21 and light exit surfaces 22, each corresponding to a plurality of display screens 10. Light emitted from each display screen 10 enters the color combining device 20 through the light entrance surface 21 and is guided by the color combining device 20 to enter the projection lens 60 through the light exit surface 22. This eliminates the need for light processing and guidance components for each display screen 10, resulting in a compact micro-projection light engine structure, significantly reducing its size and weight, and thus enabling near-eye display devices to meet wearable ergonomic requirements.

[0027] At least one matting element 50 is provided at the light incident surface 21 .

[0028] Understandably, see Figure 2 as well as Figure 3 , Figure 2 This is a schematic diagram of the first structure of a micro-projection light engine in the prior art. Figure 3 Figure 1 is a schematic diagram illustrating stray light and a display screen in the prior art. Under existing circumstances, a portion of light emitted from pixels at the edge of display screen 10 reaches the side of color combiner 20 at an incident angle β greater than the angle of total internal reflection (i.e., β > arcsin(1 / n), where n is the refractive index of the material of color combiner 20). At this point, the light undergoes total internal reflection, which is projected through projection lens 60 and forms stray light 300 on both sides of display screen 200.

[0029] In the examples of this application, please continue to refer to Figure 1 as well as Figure 4 , Figure 4 Schematic diagram of a display screen provided by an embodiment of the present application. The micro-projection light engine 100 includes at least one light-reflecting element 50, which is disposed at the light incident surface 21 and is configured to block the reflected propagation of light, thereby reducing or even eliminating stray light 300 formed on both sides of the display screen 200 by totally reflected light.

[0030] Among them, the light incident surface 21 has a reflective area, and part of the light emitted by the display screen 10 can be reflected on the reflective area of ​​the light incident surface 21 and then pass through the projection lens 60. The matte element 50 is set in the reflective area to absorb the stray light caused by the above-mentioned total reflection, and can also absorb the stray light caused by the reflection of the glue, optical parts, and structural parts, thereby greatly improving the display quality of the projection picture.

[0031] In order not to affect the brightness of the final image and not to block the emission of normal light, the light-extinguishing element 50 is disposed near the edge of the reflective area of ​​the light incident surface 21 .

[0032] The light-removing element 50 can effectively absorb stray light. Figure 5 , Figure 5 This is a schematic diagram of the structure of a color combining device according to an embodiment of the present application. In some embodiments, the matte element 50 is an aperture; in some embodiments, the matte element 50 is a layer of black ink at the edge of the light incident surface 21 of the color combining device 20. The matte element 50 can be formed by one or more of spray painting, ink coating, silk screen printing, and photolithography.

[0033] In other cases, see Figure 6 , Figure 6 This is a schematic diagram of a second structural embodiment of a conventional micro-projection light engine. A portion of light emitted from pixels at the edge of display screen 10 reaches the side of color combiner 20 at an incident angle β less than the angle of total internal reflection (i.e., β < arcsin(1 / n), where n is the refractive index of the material of color combiner 20). In this case, total internal reflection (TOR) does not occur. Instead, the TOR light is refracted through color combiner 20 but does not pass through the lens.

[0034] In some embodiments, see Figure 7 , Figure 7 This is a schematic diagram of a second structural embodiment of a micro-projection light engine provided by an embodiment of the present application. The micro-projection light engine 100 includes multiple display screens 10 and a color combining device 20. The color combining device 20 has multiple light incident surfaces 21 and a light emitting surface 22. The multiple light incident surfaces 21 correspond one-to-one with the multiple display screens 10, and each display screen 10 is fixed to a light incident surface 21. The color combining device 20 is configured to couple light, and the coupled light is emitted from the light emitting surface 22.

[0035] See also Figure 8 , Figure 8 This is a schematic diagram of the third structure of a micro-projection light engine in the prior art. In the prior art, a color combining device 102 is fixed in a bracket 103 to form a prism mount. Multiple display screens 101 are mounted on three sides of the bracket 103 and secured with glue.

[0036] The display screen 10 in the embodiment of the present application is directly fixed on the light incident surface 21 of the color combining device 20 , that is, the distance between the display screen 10 and the color combining device 20 is shortened, which is conducive to miniaturization of the micro-projection light engine 100 .

[0037] Please continue reading Figure 7 The micro-projection light engine 100 also includes a projection lens 60, which is disposed on one side of the light-emitting surface 22 of the color-combining device 20. Light emitted from each display screen 10 enters the color-combining device 20 through the light-incident surface 21 and is guided by the color-combining device 20 until it enters the projection lens 60 via the light-emitting surface 22. This eliminates the need for light processing and guidance components for each display screen 10, resulting in a compact near-eye display device. This significantly reduces the size and weight of the near-eye display device, ensuring that the near-eye display meets ergonomic requirements.

[0038] In some embodiments, there are various ways to fix the display screen 10 and the color combining device 20, such as fastening the display screen 10 and the color combining device 20 by snaps or bolts. These fixing methods may cause surface damage to the color combining device 20. Figure 7 In the embodiment of the present application, the micro-projection light engine 100 further includes an adhesive layer 30 , which is disposed between the display screen 10 and the color combining device 20 . The adhesive layer 30 can fix the relative positions of the display screen 10 and the color combining device 20 without damaging the surface of the color combining device 20 .

[0039] In some embodiments, see Figure 9 , Figure 9 This is a third structural diagram of the micro-projection light engine provided in an embodiment of the present application. The micro-projection light engine 100 further includes a bracket 40, which is provided with a receiving space 41. The color combining device 20 is disposed in the receiving space 41. The bracket 40 is provided with a plurality of openings 42, which are connected to the receiving space 41. The plurality of openings 42 correspond one-to-one to the plurality of display screens 10, and each display screen 10 is disposed in an opening 42. Please continue to refer to Figure 8 In the prior art, the display screen 101 is mounted on the side of the bracket 103 away from the color combining device 102, which is equivalent to the display screen 101 being mounted on the surface of the prism mounting body, which undoubtedly increases the thickness of the micro-projection light engine 1. Figure 9In the present application, a plurality of openings 42 are provided on the bracket 40, and each display screen 10 is provided in an opening 42, so that the thickness of the bracket 40 and the display screen 10 can overlap, and the distance between the bracket 40 and the display screen 10 can be compressed. At the same time, the bracket 40 can fix the relative position of the display screen 10.

[0040] The thickness of the display screen 10 is less than or equal to the thickness of the bracket 40 , and the display screen 10 can be further embedded in the bracket 40 to shorten the distance between the display screen 10 and the color combining device 20 .

[0041] The inner wall of the bracket 40 is black to prevent light leakage.

[0042] Under the existing circumstances, a portion of the light emitted by the edge pixels of the display screen 10 reaches the side of the color combining device 102 at an incident angle β that is greater than the total reflection angle, that is, β>arcsin(1 / n), where n is the refractive index of the material of the color combining device 102. At this time, the light will undergo total internal reflection, and the totally reflected light will be projected through the projection lens, forming stray light on both sides of the display screen.

[0043] See also Figure 10 , Figure 10 This is a fourth structural diagram of the micro-projection light engine provided in an embodiment of the present application.

[0044] In an embodiment of the present application, the micro-projection light engine 100 includes at least one extinction element 50, which is arranged on the light incident surface 21 of the color combining device 20. The extinction element 50 is configured to block the reflection and propagation of light, thereby reducing or even eliminating the stray light formed by the totally reflected light on both sides of the display screen.

[0045] Specifically, the orthographic projection of the matte element 50 on the color combining device 20 is arranged around the orthographic projection of the display screen 10 on the color combining device 20 to absorb the stray light caused by the above-mentioned total reflection. It can also absorb the stray light caused by the reflection of the glue, optical parts, and the surface of the structural parts, which greatly improves the display quality of the projected image without affecting the brightness of the final image or blocking the emission of normal light.

[0046] In other cases, see Figure 1 The micro-projection light engine 100 further includes a bracket 40 having a receiving space 41. The display screen 10, the color combining device 20, and the at least one extinction element 50 are all disposed in the receiving space 41. The inner wall of the bracket 40 is configured to absorb light, so that the light is absorbed by the bracket 40 and will not be reflected or transmitted on the bracket 40, resulting in the generation of stray light 300.

[0047] The inner wall of the bracket 40 may be made of a color with a low reflectivity such as black.

[0048] In some embodiments, see Figure 11 as well as Figure 12 , Figure 11 This is a fifth structural diagram of the micro-projection light engine provided in an embodiment of the present application. Figure 12 This is a sixth structural diagram of a micro-projection light engine provided in an embodiment of the present application. The color combining device 20 includes a plurality of light-input prisms and a light-output prism 24. The light-input prisms are interconnected, with the connecting surface between adjacent light-input prisms forming a coupling port. The light-output prism 24 is connected to at least one light-input prism and has a light-output surface 22. It will be understood that light emitted from the display screen 10 enters the light-input prism, couples with it, and is then guided through the light-output prism 24 to enter the projection lens 60.

[0049] The plurality of display screens 10 include a first display screen 11, a second display screen 12, and a third display screen 13. The first display screen 11, the second display screen 12, and the third display screen 13 can all be Micro-LED display screens 10. The first display screen 11 can emit red light, the second display screen 12 can emit blue light, and the third display screen 13 can emit green light.

[0050] The multiple light incident prisms include a first light incident prism 231, a second light incident prism 232 and a third light incident prism 233. The third light incident prism 233 is connected between the first light incident prism 231 and the second light incident prism 232. The side of the first light incident prism 231 close to the third light incident prism 233 is a first coupling inlet, the side of the second light incident prism 232 close to the third light incident prism 233 is a second coupling inlet, and the side of the third light incident prism 233 close to the first coupling inlet and the second coupling inlet is a third coupling inlet. The first display screen 11 corresponds to the first coupling inlet, the second display screen 12 corresponds to the second coupling inlet, and the third display screen 13 corresponds to the third coupling inlet.

[0051] The light emitted by the first display screen 11 can be totally reflected when entering the first coupling port, the light emitted by the second display screen 12 can be totally reflected when entering the second coupling port, and the light emitted by the third display screen 13 can be transmitted when entering the third coupling port, which is beneficial to improving the utilization rate of light.

[0052] An embodiment of the present application provides a near-eye display device, which includes the above-mentioned micro-projection light engine 100. Specifically, the near-eye display device can be an extended reality (XR) device, wherein the extended reality device includes virtual reality (VR), augmented reality (AR), and mixed reality (MR) devices. More specifically, the extended reality device can be a wearable electronic device in the form of glasses or a head-mounted display. More specifically, it can be an optical see-through AR glasses in the form of glasses. The AR glasses include a wearable bracket and a diffraction waveguide module, which is connected to the wearable bracket. The wearable bracket includes temples and a frame, the temples are connected to the frame, and the frame is connected to the diffraction waveguide module. The frame is used to support the diffraction waveguide module, and the temples are used to be worn on the user's head. The micro-projection light engine can be located in the cavity of the temples or in the cavity of the frame. It can be understood that the miniaturization of the micro-projection light engine facilitates more possibilities in the structural design of the glasses. AR glasses can also include electronic components such as batteries, sensors, speakers, cameras, circuit boards, etc.

[0053] In the micro-projection light engine 100 and near-eye display device provided in the embodiments of the present application, the micro-projection light engine 100 includes multiple display screens 10, a color combining device 20, at least one light extinction element 50, and a projection lens 60. The color combining device 20 has multiple light entrance surfaces 21 and light exit surfaces 22, each corresponding one-to-one with the multiple display screens 10. The color combining device 20 is configured to couple light. The light extinction element 50 is provided on the color combining device 20, located at the light entrance surface 21 of the color combining device 20, to block the reflected propagation of light. This prevents the reflected light from entering the projection lens, ultimately reducing or even eliminating stray light 300.

[0054] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0055] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, features specified as "first" or "second" may explicitly or implicitly include one or more features.

[0056] The above describes in detail the micro-projection light engine and near-eye display device provided in the embodiments of this application. Specific examples are used herein to illustrate the principles and implementation methods of this application. The description of the above embodiments is intended only to facilitate understanding of this application. Furthermore, those skilled in the art will appreciate that variations in the specific implementation methods and scope of application may occur based on the concepts of this application. In summary, the contents of this specification should not be construed as limiting this application.

Claims

1. A micro-projection light engine, characterized in that: include: Multiple displays; a color combining device, the color combining device having a plurality of light incident surfaces and a light emitting surface, the plurality of light incident surfaces corresponding one-to-one to the plurality of display screens, the color combining device being configured to couple light; at least one light-removing element, the light-removing element being disposed at the light incident surface and configured to block reflection and propagation of light; A projection lens is disposed at the light-emitting surface and is configured to receive the light coupled by the color combining device.

2. The micro-projection light engine according to claim 1, wherein: The light incident surface has a reflective area, and part of the light emitted from the display screen can be reflected on the reflective area of ​​the light incident surface and then pass through the projection lens. The light extinction element is arranged in the reflective area.

3. The micro-projection light engine according to claim 2, wherein: The matte element is arranged near an edge of the reflective area of ​​the light incident surface.

4. The micro-projection light engine according to any one of claims 1 to 3, wherein: The matting element is an aperture.

5. The micro-projection light engine according to any one of claims 1 to 3, characterized in that: Each of the display screens is fixed on one of the light incident surfaces.

6. The micro-projection light engine according to claim 5, wherein: It also includes an adhesive layer, which is arranged between the display screen and the color combining device.

7. The micro-projection light engine according to claim 5, wherein: The orthographic projection of the matte element on the color combining device is arranged around the orthographic projection of the display screen on the color combining device.

8. The micro-projection light engine according to claim 5, wherein: It also includes a bracket, which is provided with a storage space, and the color combining device is arranged in the storage space. The bracket is provided with multiple openings, and the openings are connected to the storage space. The multiple openings correspond one-to-one to multiple display screens, and each display screen is arranged in one of the openings.

9. The micro-projection light engine according to any one of claims 1 to 3, characterized in that: It also includes a bracket having a receiving space, wherein the display screen, the color combining device and at least one of the light-extinguishing components are all arranged in the receiving space; and the inner wall of the bracket is configured to absorb light.

10. A near-eye display device, characterized in that: The micro-projection light engine comprises the micro-projection light engine according to any one of claims 1 to 9.

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