Optical assembly and near-eye display device
By introducing composite film groups and semi-reflective and semi-transparent layers into the optical components, light is folded in the optical mirror, extending the focal length. This solves the imaging quality and thickness problems caused by heavy lenses, and achieves the thinning of optical components and high imaging quality.
Patent Information
- Application Number
- CN202423166646.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-19
- Publication Date
- 2025-11-21
- Estimated Expiration
- 2034-12-19
AI Technical Summary
Existing catadioptric optical components have increased lens thickness due to increased focal length, which affects image quality and overall weight. Furthermore, thinning the lens will sacrifice some optical performance.
The design employs a combination of composite film and semi-reflective layer to fold light within the optical mirror, extending the focal length. Thinner lenses are used instead of heavy lenses to ensure high image quality.
It achieves a thinner and lighter optical component while maintaining or improving image quality and enhancing display performance.
Smart Images
Figure CN223582245U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to near eye display technical field especially relates to an optical assembly and near eye display device. BACKGROUND
[0002] In recent years, augmented reality glasses (AR glasses) have rapidly emerged and successfully penetrated into many fields such as military equipment, industrial production, medical diagnosis and daily life. The magic of such glasses is that they can cleverly combine virtual images with real-world scenes and project them into the user's eyes, allowing the observer to see virtual elements embedded in the real scene. There are many types of AR glasses on the market based on flat semi-transparent semi-reflective, free-form surface semi-transparent semi-reflective, geometric waveguide, catadioptric structure (commonly known as Birdbath), and diffractive waveguide. Among them, the catadioptric structure has been widely used in commercial products due to its excellent optical resolution and low distortion characteristics.
[0003] However, the current optical assembly using catadioptric structure faces a significant challenge: in order to magnify the display image projected by the light engine and deliver it to the light deflection assembly, a lens with a larger focal length must be used. The increase in focal length directly leads to an increase in lens thickness, which in turn makes the entire optical assembly thick and heavy. In order to control the overall thickness, it is often necessary to sacrifice some optical performance and adopt a thinning lens approach, but this inevitably affects the imaging quality and makes the image performance poor. SUMMARY
[0004] The present application provides an optical assembly and a near-eye display device that can improve imaging quality without increasing thickness.
[0005] The present application provides an optical assembly, comprising:
[0006] a first optical mirror;
[0007] a first semi-reflective semi-transmissive layer disposed on the light entrance side of the first optical mirror;
[0008] a composite film group disposed on the side of the first optical mirror away from the first semi-reflective semi-transmissive layer, the composite film group and the first semi-reflective semi-transmissive layer causing the light rays to be emitted from the composite film group after being folded back in the first optical mirror;
[0009] a light deflection assembly disposed on the light exit side of the composite film group.
[0010] In some embodiments, the composite film set includes a first quarter wave plate disposed on a side of the first optical mirror away from the first half reflective half transmissive layer, and a first polarized reflective sheet disposed on a side of the first quarter wave plate away from the first optical mirror.
[0011] In some embodiments, the first optical mirror includes a first sub-lens and a second sub-lens disposed on an out-coupling side of the first sub-lens, and the first half reflective half transmissive layer is disposed on an in-coupling side of the first sub-lens; and the composite film set is disposed on a side of the second sub-lens away from the first sub-lens.
[0012] In some embodiments, the optical assembly further includes a second optical mirror disposed on an out-coupling side of the first optical mirror, and the composite film set is disposed between the first optical mirror and the second optical mirror.
[0013] In some embodiments, the light deflection assembly includes a prism having a first surface, a second surface and a third surface connected to each other, the first surface facing an out-coupling side of the composite film set; a second quarter wave plate disposed on the second surface; a second half reflective half transmissive layer disposed on a side of the second quarter wave plate away from the prism; and a second polarized reflective sheet disposed on the third surface.
[0014] In some embodiments, the second half reflective half transmissive layer includes a flat mirror and a second half reflective half transmissive film disposed on the flat mirror.
[0015] In some embodiments, the second half reflective half transmissive layer includes a first lens and a second half reflective half transmissive film disposed on the first lens.
[0016] In some embodiments, the first optical mirror is a flat mirror or a lens.
[0017] Embodiments of the present application also provide a near-eye display device, including:
[0018] a light engine;
[0019] an optical assembly, the optical assembly being the optical assembly described above, the optical assembly disposed on an out-coupling side of the light engine.
[0020] In some embodiments, the near-eye display device further includes a first linear polarized sheet disposed on an out-coupling side of the light engine, and a third quarter wave plate disposed on a side of the first linear polarized sheet away from the light engine.
[0021] In the optical assembly and the near-eye display device provided by the embodiments of the present application, the optical assembly comprises a first optical lens, a first half-reflection half-transmission layer, and a composite film group. The first half-reflection half-transmission layer is arranged on the light-incident side of the first optical lens, and the composite film group is arranged on the side of the first optical lens away from the first half-reflection half-transmission layer. Under the joint action of the composite film group and the first half-reflection half-transmission layer, the light is folded in the first optical lens, which substantially increases the propagation distance of the light, and thus the focal length is virtually lengthened. This makes it possible to replace the traditional thick lens with a thinner lens, thereby realizing the lightness and thinness of the optical assembly while ensuring high imaging quality. BRIEF DESCRIPTION OF DRAWINGS
[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.
[0023] Figure 1 The first structural schematic diagram of the optical assembly provided by the embodiments of the present application.
[0024] Figure 2 The second structural schematic diagram of the optical assembly provided by the embodiments of the present application.
[0025] Figure 3 The third structural schematic diagram of the optical assembly provided by the embodiments of the present application.
[0026] Figure 4 The fourth structural schematic diagram of the optical assembly provided by the embodiments of the present application.
[0027] Figure 5 The fifth structural schematic diagram of the optical assembly provided by the embodiments of the present application.
[0028] Figure 6 The MTF diagram of the optical assembly provided by the embodiments of the present application.
[0029] Figure 7 The first structural schematic diagram of the near-eye display device provided by the embodiments of the present application.
[0030] Figure 8 The second structural schematic diagram of the near-eye display device provided by the embodiments of the present application. DETAILED DESCRIPTION
[0031] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.
[0032] The optical assembly and the near-eye display device provided by the embodiments of the present application can improve the imaging quality without increasing the thickness. The specific description will be made below with reference to the drawings.
[0033] Please refer to Figure 1 , Figure 1 The first structural schematic diagram of the optical assembly provided by the embodiments of the present application is shown.
[0034] The optical assembly 10 provided by the embodiments of the present application includes a first optical mirror 11, a first half-reflection half-transmission layer, a composite film group 13 and a light deflection assembly 14. The first half-reflection half-transmission layer is arranged on the light-incident side of the first optical mirror 11. The composite film group 13 is arranged on the side of the first optical mirror 11 away from the first half-reflection half-transmission layer, and the composite film group 13 and the first half-reflection half-transmission layer make the light rays exit from the composite film group 13 after the light rays are folded in the first optical mirror 11. The light deflection assembly 14 is arranged on the light-emitting side of the composite film group 13.
[0035] The first optical mirror 11 can be a flat mirror or a lens. The first optical mirror 11 can carry and support the first half-reflection half-transmission layer and the composite film group 13. When the first optical mirror 11 is a lens, the lens has a certain positive focal power and can magnify the image emitted by the light engine.
[0036] The first half-reflection half-transmission layer can transmit part of the light rays and reflect part of the light rays. The first half-reflection half-transmission layer can be used as a light splitting element. When the light rays encounter the half-reflection half-transmission film, part of the light rays will be reflected by the film and return along a specific direction according to the law of reflection, and the other part of the light rays will penetrate the half-reflection half-transmission film and continue to advance along the original propagation direction or after a certain refraction.
[0037] The composite film group 13 can change the polarization direction of the light rays and selectively reflect the light rays transmitted through a specific polarization direction. For example, the composite film group 13 can convert circularly polarized light into linearly polarized light, and can also convert first linearly polarized light into second linearly polarized light, the polarization directions of the first linearly polarized light and the second linearly polarized light being perpendicular to each other.
[0038] With the above characteristics of the first semi-reflective semi-transmissive layer and the composite film group 13, the light can be folded in the first optical mirror 11 and then emitted from the composite film group 13, as follows: the first circularly polarized light at least partially passes through the first semi-reflective semi-transmissive layer and the first optical mirror 11, and is converted into the first linearly polarized light at the composite film group 13 and reflected, and the polarization state of the reflected light changes, i.e., the first linearly polarized light is converted into the second circularly polarized light, which continues to propagate to the first semi-reflective semi-transmissive layer, at least partially reflected by the first semi-reflective semi-transmissive layer back to the composite film group 13, continues to pass through the composite film group 13 and is converted into the second linearly polarized light, and then enters the light deflection assembly 14. The handedness of the first circularly polarized light and the second circularly polarized light can be the same or opposite.
[0039] Therefore, under the joint action of the composite film group 13 and the first semi-reflective semi-transmissive layer, the light is folded in the first optical mirror 11, which substantially increases the propagation distance of the light, thereby virtually extending the focal length. This makes it possible to replace the traditional thick lens with a thinner lens, thereby realizing the lightness and thinness of the optical assembly 10 while ensuring high imaging quality.
[0040] The composite film group 13 includes a first quarter-wave plate 131 and a first polarized reflective sheet 132, the first quarter-wave plate 131 is arranged on the side of the first optical mirror 11 away from the first semi-reflective semi-transmissive layer, and the first polarized reflective sheet 132 is arranged on the side of the first quarter-wave plate 131 away from the first optical mirror 11.
[0041] The quarter-wave plate can change the polarization state of the light. For example, the circularly polarized light passes through the quarter-wave plate once to be converted into linearly polarized light; for another example, the linearly polarized light passes through the quarter-wave plate twice to be converted into circularly polarized light; for another example, the linearly polarized light passes through the first quarter-wave plate 131 twice to be converted into linearly polarized light perpendicular to the original polarization direction.
[0042] The polarized reflective sheet is an optical thin film that can selectively reflect and transmit light of a specific polarization direction. In the embodiment of the present application, the first polarized reflective sheet 132 can reflect the first linearly polarized light and transmit the second linearly polarized light.
[0043] Under the action of the first quarter-wave plate 131 and the first polarized reflection sheet 132, the propagation process of the light in the optical assembly 10 can be: the first circularly polarized light at least partially passes through the first half-reflective half-transmissive layer, the first optical mirror 11, and the first quarter-wave plate 131, and is converted into first linearly polarized light. After the first linearly polarized light is reflected by the first polarized reflection sheet 132, it passes through the first quarter-wave plate 131 again, and at this time, the first linearly polarized light is converted into second circularly polarized light. The second circularly polarized light continues to propagate to the first half-reflective half-transmissive layer and is at least partially reflected by the first half-reflective half-transmissive layer back to the first quarter-wave plate 131. The first quarter-wave plate 131 can convert the circularly polarized light into second linearly polarized light. The second linearly polarized light continues to pass through the first polarized reflection sheet 132 and enters the light deflection assembly 14.
[0044] Referring to Figure 2 , Figure 2 A second structural schematic diagram of an optical assembly provided by an embodiment of the present application is shown. In some embodiments, the first optical mirror 11 includes a first sub-lens 111 and a second sub-lens 112. The second sub-lens 112 is arranged on the light-outgoing side of the first sub-lens 111, and the first half-reflective half-transmissive layer is arranged on the light-ingoing side of the first sub-lens 111. The composite film set 13 is arranged on the side of the second sub-lens 112 away from the first sub-lens 111. The first sub-lens 111 and the second sub-lens 112 can each be a convex lens with positive focal power. The first half-reflective half-transmissive layer is arranged on the first sub-lens 111, and the composite film set 13 is arranged on the second sub-lens 112. In this way, the distance between the first sub-lens 111 and the second sub-lens 112 can be adjusted to achieve long-focus adjustment. This is suitable for flexible adjustment of the optical path and can significantly improve the display quality.
[0045] In other embodiments, the optical assembly 10 further includes a second optical mirror arranged on the light-outgoing side of the first optical mirror 11, and the composite film set 13 is arranged between the first optical mirror 11 and the second optical mirror. The second optical mirror can further adjust the light propagating from the first optical mirror 11 and timely adjust the propagation direction of the light, thereby improving the stability of the light propagation. The second optical mirror can be a lens.
[0046] Referring to Figure 3 , Figure 3A third structure diagram of the optical assembly provided in the embodiments of the present application is shown. In some embodiments, the light deflection assembly 14 includes a prism 141, a second quarter-wave plate 142, a second semi-reflective and semi-transmissive layer 143, and a second polarized reflective sheet 144. The prism 141 has a first surface 1411, a second surface 1412, and a third surface 1413 connected to each other, and the first surface 1411 faces the light exit side of the composite film set 13. The second quarter-wave plate 142 is arranged on the second surface 1412. The second semi-reflective and semi-transmissive layer 143 is arranged on a side of the second quarter-wave plate 142 away from the prism 141. The second polarized reflective sheet 144 is arranged on the third surface 1413.
[0047] The second linearly polarized light propagating from the first optical mirror 11 enters the first surface 1411 of the prism 141, and then is reflected from the second surface 1412 to the third surface 1413. The second linearly polarized light is reflected by the second polarized reflective sheet 144 back to the second surface 1412, and then passes through the second surface 1412 and the second quarter-wave plate 142. At this time, the second linearly polarized light is converted into first circularly polarized light. The first circularly polarized light continues to propagate to the second semi-reflective and semi-transmissive layer 143, and at least part of the first circularly polarized light is reflected by the second semi-reflective and semi-transmissive layer 143 back to the second quarter-wave plate 142. The second quarter-wave plate 142 can convert the first circularly polarized light into first linearly polarized light. The first linearly polarized light continues to pass through the second polarized reflective sheet 144 and enters the light deflection assembly 14.
[0048] Please refer to Figure 4 , Figure 4 A fourth structure diagram of the optical assembly provided in the embodiments of the present application is shown. In some cases, the second semi-reflective and semi-transmissive layer 143 includes a flat mirror 1431 and a second semi-reflective and semi-transmissive film arranged on the flat mirror 1431. The flat mirror 1431 is in the form of a flat plate, and is easy to manufacture and has a low cost.
[0049] Please refer to Figure 3 In other cases, the second semi-reflective and semi-transmissive layer 143 includes a first lens 1432 and a second semi-reflective and semi-transmissive film arranged on the first lens 1432. The first lens 1432 has optical power. When the optical power of the first lens 1432 is positive, the first lens 1432 can effectively converge light rays, which greatly enhances the definition of an image and provides a user with a more delicate and realistic visual experience. When the optical power of the first lens 1432 is negative, the lens can help myopic users clearly observe the surrounding environment without wearing glasses, greatly improving the convenience and comfort of use.
[0050] In some embodiments, please refer to Figure 5, Figure 5 A fifth structural schematic diagram of an optical assembly provided in an embodiment of the present application is provided. The light deflection assembly 14 further comprises a compensating lens 145 for eliminating aberration generated when the prism 141 transmits ambient light. The compensating lens 145 and the prism 141 can use the same material so that the refractive index and Abbe number remain consistent. The compensating lens 145 is consistent with the surface shape of the second surface 1412 of the prism 141, and the second polarized reflection sheet 144 is clamped between the compensating lens 145 and the prism 141. The side of the compensating lens 145 close to the human eye is approximately parallel to the side of the prism 141 away from the human eye, so as to maintain the light propagating in the same direction.
[0051] In some embodiments, please refer to Figure 5 The light polarization assembly further comprises a second linear polarized sheet 146, which is arranged on the side of the second polarized reflection sheet 144 away from the prism 141, and the second linear polarized sheet 146 can block the first linear polarized light and prevent the second linear polarized light. It can be understood that when the second polarized reflection sheet 144 reflects the second linear polarized light, part of the second linear polarized light can still pass through the second polarized reflection sheet 144, and the second linear polarized sheet 146 can block this part of light to prevent the second linear polarized light from entering the human eye.
[0052] Please refer to Figure 6 , Figure 6 The MTF (Modulation Transfer Function) diagram of the optical assembly provided in an embodiment of the present application is provided. The MTF diagram of the optical assembly 10 can show that the average MTF of the full field of view of the optical assembly 10 is greater than 0.5 at 20 lp / mm. The field of view angle of the optical assembly 10 is 40° to 60°, which is significantly increased compared with the field of view angle of the optical assembly in the prior art. The distortion of the displayed image of the optical assembly 10 is less than 1%.
[0053] Please refer to Figure 7 , Figure 7 A first structural schematic diagram of a near-eye display device provided in an embodiment of the present application is provided. The embodiment of the present application further provides a near-eye display device, which comprises a light engine and an optical assembly 10, the optical assembly 10 being the optical assembly 10 described above, and the optical assembly 10 being arranged on the light-outgoing side of the light engine.
[0054] The near-eye display device further comprises a first linear polarized sheet 30 and a third quarter-wave plate 40, the first linear polarized sheet 30 being arranged on the light-outgoing side of the light engine, and the third quarter-wave plate 40 being arranged on the side of the first linear polarized sheet 30 away from the light engine.
[0055] In order to optimize the light emitted by the light engine, the first linear polarizer 30 and the third quarter-wave plate 40 are also introduced in this embodiment. They are arranged on the light-emitting side of the light engine to convert the light emitted by the light engine into circularly polarized light, thereby ensuring the brightness of the display image and reducing light leakage. At the same time, these two components also have the effect of eliminating reflected stray light, further reducing aberrations and ghost images caused by optical gaps.
[0056] The near-eye display device is a device configured to present display content directly in front of the user's eyes within a certain distance (usually 2-5 cm), such as a head-mounted display in a virtual reality (VR) device, optical see-through glasses in an augmented reality (AR) device, etc. The near-eye display device includes but is not limited to head-mounted devices such as AR glasses, AR headsets, etc., which have a wide range of applications and are flexible.
[0057] The light engine is responsible for emitting light and forming images. The light engine in this embodiment can include Micro LED display screens, Micro OLED display screens, laser beam scanning display screens (LBS display screens), digital mirror display screens (DMD display screens), and other types. These advanced display screen technologies ensure high resolution and color accuracy of virtual images, providing users with a more realistic and vivid visual experience. The light engine is also known as a micro projection light machine, a micro display screen, a light machine, etc. These terms can be used interchangeably in this application unless otherwise specified. The display screen size of the light engine can be 0.3 to 0.6 inches.
[0058] The optical assembly 10 adopts the innovative design in the above-mentioned embodiments, including lenses, beam splitters, half-mirrors, quarter-wave plates, and supporting lenses, etc. These components work together not only to achieve clear imaging of virtual images but also to ensure smooth transmission of real scene light, thereby realizing real-time superimposition of virtual information and real scene and providing users with an immersive virtual-real fusion experience.
[0059] In addition, please refer to Figure 8 , Figure 8 The second structural diagram of the near-eye display device provided by the embodiments of the present application is shown. The near-eye display device is also equipped with a processor, a fixing member 50, and other key components. The processor is responsible for accepting instructions, data processing, and controlling other components to ensure smooth overall operation of the device. The fixing member 50 includes a glasses leg 51 and a glasses frame 52, which are used to mount, fix, or carry the above-mentioned optical assembly 10, ensuring the stability and comfort of the entire device, and facilitating long-term wear by users.
[0060] The near-eye display device can also include sensors, circuits, output devices, and components such as batteries or solar cells. The sensors can monitor the user's head movements or eye movements in real time, adjusting the position and angle of the virtual image to further enhance the user experience. The circuit is responsible for connecting various components to achieve information transmission and processing. The output device is used to display virtual images or issue sound prompts to the user. The battery or solar cell provides continuous power support for the device to ensure long-term operation of the device.
[0061] In addition, the near-eye display device can also adopt a wraparound lens, adaptive glasses or auxiliary frame design to meet the wearing needs of different users. At the same time, the device can be equipped with a belt for fixing to ensure that the user can maintain stability and comfort during use.
[0062] The optical assembly 10 and the near-eye display device provided by the embodiments of the present application include a first optical mirror 11, a first half-reflection half-transmission layer, and a composite film group 13. The first half-reflection half-transmission layer is arranged on the light-in side of the first optical mirror 11, and the composite film group 13 is arranged on the side of the first optical lens away from the first half-reflection half-transmission layer. Under the joint action of the composite film group 13 and the first half-reflection half-transmission layer, the light is folded in the first optical mirror 11, which substantially increases the propagation distance of the light, thereby virtually extending the focal length. This makes it possible to replace the traditional thick and heavy lens with a thinner lens, thereby realizing the thinness of the optical assembly 10 while ensuring high imaging quality.
[0063] In the above embodiments, the description of each embodiment focuses on different aspects. The parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.
[0064] In the description of the present application, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more features.
[0065] The optical assembly and the near-eye display device provided by the embodiments of the present application are described in detail above. The principles and implementation modes of the present application are described by applying specific examples in this paper. The above description of the embodiments is only used to help understand the present application. Meanwhile, for those skilled in the art, the specific implementation modes and application scope of the present application will be changed according to the idea of the present application. In summary, the content of the specification should not be understood as a limitation of the present application.
Claims
1. An optical assembly comprising: Comprising: a first optical mirror; a first half reflective half transmissive layer, the first half reflective half transmissive layer being disposed on a light entrance side of the first optical mirror; a composite film set, the composite film set being disposed on a side of the first optical mirror away from the first half reflective half transmissive layer, the composite film set and the first half reflective half transmissive layer being such that light rays are emitted from the composite film set after being folded back in the first optical mirror; a light deflection assembly, the light deflection assembly being disposed on a light exit side of the composite film set.
2. The optical assembly of claim 1, wherein, The composite film set comprises a first quarter wave plate and a first polarized reflective sheet, the first quarter wave plate being disposed on a side of the first optical mirror away from the first half reflective half transmissive layer, the first polarized reflective sheet being disposed on a side of the first quarter wave plate away from the first optical mirror.
3. The optical assembly of claim 1 or 2, wherein, The first optical mirror comprises a first sub-lens and a second sub-lens, the second sub-lens being disposed on a light exit side of the first sub-lens, the first half reflective half transmissive layer being disposed on a light entrance side of the first sub-lens; the composite film set being disposed on a side of the second sub-lens away from the first sub-lens.
4. The optical assembly of claim 1 or 2, wherein, Further comprising a second optical mirror, the second optical mirror being disposed on a light exit side of the first optical mirror, the composite film set being disposed between the first optical mirror and the second optical mirror.
5. The optical assembly of claim 1 or 2, wherein, The light deflection assembly comprises a prism, a second quarter wave plate, a second half reflective half transmissive layer and a second polarized reflective sheet, the prism having a first surface, a second surface and a third surface connected to each other, the first surface being directed towards the light exit side of the composite film set; the second quarter wave plate being disposed on the second surface; the second half reflective half transmissive layer being disposed on a side of the second quarter wave plate away from the prism; the second polarized reflective sheet being disposed on the third surface.
6. The optical assembly of claim 5, wherein, The second half reflective half transmissive layer comprises a flat mirror and a second half reflective half transmissive film, the second half reflective half transmissive film being disposed on the flat mirror.
7. The optical assembly of claim 5, wherein, The second half reflective half transmissive layer comprises a first lens and a second half reflective half transmissive film, the second half reflective half transmissive film being disposed on the first lens.
8. The optical assembly of claim 1 or 2, wherein, The first optical mirror is a flat mirror or a lens.
9. A near-eye display device, comprising: Comprising: a light engine; an optical assembly, the optical assembly being any one of claims 1 to 8, the optical assembly being disposed on a light exit side of the light engine.
10. The near-eye display device of claim 9, wherein, Further comprising a first linear polarized sheet and a third quarter wave plate, the first linear polarized sheet being disposed on the light exit side of the light engine, the third quarter wave plate being disposed on a side of the first linear polarized sheet away from the light engine.