Optical module with reduced distortion and head-mounted display device
By optimizing the structure of the optical module and the light propagation path, the problem of large distortion in the AR module was solved, achieving a compact design and high-quality imaging of the optical module, thus improving the user experience.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU HONGYI PHOTOELECTRIC TECH CO LTD
- Filing Date
- 2025-09-10
- Publication Date
- 2026-06-16
AI Technical Summary
Existing AR modules suffer from problems such as large distortion and excessive thickness, which negatively impact the user experience.
An optical module was designed, including a display unit and multiple optical elements. By combining specific structures and film layers, the light propagation path is optimized to reduce distortion. The prism structure and polarization beam splitter are used to achieve effective control and compensation of light.
It achieves small size, light weight, low distortion, good imaging quality, and large field of view of the optical module, thus improving the user experience.
Smart Images
Figure CN224366269U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of optical imaging technology, specifically relating to an optical module and head-mounted display device for reducing distortion. Background Technology
[0002] Augmented display optical display technology is a technology that can project and magnify display images. This technology not only expands upon traditional display technologies but also introduces entirely new experiences: merging the real and virtual worlds, making life more convenient and enriching entertainment. It is currently widely used in education, healthcare, aerospace, and many other fields.
[0003] As augmented reality (AR) display technology continues to develop and its application areas expand, the requirements for display devices are also increasing. Current AR modules commonly suffer from problems such as large distortion and excessive thickness, significantly impacting the user experience. Utility Model Content
[0004] The purpose of this invention is to provide an optical module that reduces distortion. It is small in size, light in weight, has low stray lightness, low distortion, good imaging quality, and a large field of view, which greatly improves the user experience.
[0005] Another objective of this invention is to provide a head-mounted display device that is lightweight and easy to wear.
[0006] The embodiments of this utility model are implemented as follows:
[0007] The present invention provides an optical module for reducing distortion, comprising a display unit, a first optical element, a second optical element, a third optical element, a fourth optical element, and a fifth optical element;
[0008] The first optical element is disposed in the light-emitting path of the display unit;
[0009] The second optical element is disposed on the transmitted light path of the first optical element. The second optical element is a prism structure with its upper surface facing the first optical element. A first quarter-wave plate and an AR anti-reflection film are sequentially disposed on its front surface, and its rear surface is an inclined surface that slopes from top to bottom and forward.
[0010] The third optical element is disposed in front of the second optical element;
[0011] The fourth optical element is disposed on the rear side of the second optical element. The fourth optical element has a prism structure, and its front surface is an inclined surface that slopes from top to bottom and corresponds to the rear surface of the second optical element. A polarizing beam splitter is provided between the front surface of the fourth optical element and the rear surface of the second optical element. A polarizing reflective film and a second quarter-wave plate are provided sequentially on the rear surface of the fourth optical element.
[0012] The fifth optical element is disposed on the rear side of the fourth optical element, and a semi-transparent and semi-reflective film is provided on the side of the fifth optical element away from the fourth optical element.
[0013] Furthermore, the AR antireflective film is used to reflect light with an incident angle greater than or equal to 40° and to transmit light with an incident angle less than or equal to 25°.
[0014] Furthermore, a polarizer is provided between the display unit and the first optical element.
[0015] Furthermore, the first optical element is a transmission mirror.
[0016] Furthermore, the third optical element is a reflector.
[0017] Furthermore, the polarization beam splitter is a composite functional film layer composed of one or more of the following: a polarizing reflector, a linear polarizer, a quarter-wave plate, a half-wave plate, and a reflective film layer.
[0018] Furthermore, the fifth optical element is a transmission mirror.
[0019] Furthermore, the optical surfaces of the first optical element and the second optical element are planar, spherical, aspherical, or freeform surfaces.
[0020] Furthermore, the optical surface of the fifth optical element is either a plane or a curved surface.
[0021] An embodiment of this utility model also provides a head-mounted display device, including a wearable component and the aforementioned optical module, wherein the optical module is disposed on the wearable component.
[0022] The beneficial effects of this utility model are as follows:
[0023] The distortion-reducing optical module provided by this utility model has a compact structure, small size, light weight, low stray lightness, low distortion, good imaging quality, and a field of view of over 46°, which greatly improves the user experience.
[0024] The head-mounted display device provided by this utility model has a simple manufacturing process, low cost, light weight, and is easy to wear, greatly improving the user's wearing experience. Attached Figure Description
[0025] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.
[0026] Figure 1 This is an architectural diagram of the distortion-reducing optical module in Embodiment 1;
[0027] In the figure: 1-First optical element; 2-Second optical element; 21-First quarter-wave plate; 22-AR anti-reflection coating; 3-Third optical element; 4-Fourth optical element; 41-Polarization beam splitter; 42-Polarization reflective coating; 43-Second quarter-wave plate; 5-Fifth optical element; 51-Semi-transparent and semi-reflective coating; 6-Display unit; 7-Polarization element. Detailed Implementation
[0028] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can typically be arranged and designed in various different configurations.
[0029] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0030] It should be noted that, where there is no conflict, the embodiments and features in the embodiments of this utility model can be combined with each other.
[0031] In the description of this utility model, it should be noted that the terms "upper," "front," "rear," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this utility model. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. Example 1
[0032] refer to Figure 1 As shown, Embodiment 1 of this utility model provides an optical module for reducing distortion, including a display unit 6, a first optical element 1, a second optical element 2, a third optical element 3, a fourth optical element 4, and a fifth optical element 5.
[0033] The display unit 6 mainly functions to emit light. The display unit 6 can display 2D or 3D images or videos, and can be an OLED display, LCD display, LCOS display, micro-LED display, or mini-LED display.
[0034] The first optical element 1 is a transmission mirror. The first optical element 1 is disposed in the light output path of the display unit 6. The number of first optical elements 1 can be one or a group of multiple lenses.
[0035] The first optical element 1 is used to control light, improve image quality parameters such as image distortion and resolution, and reduce the module size.
[0036] The two optical surfaces of the first optical element 1 can be processed into planar, spherical, aspherical, or freeform surfaces.
[0037] A polarizing element 7 is provided between the display unit 6 and the first transmission mirror. The polarizing element 7 can be disposed on the light-emitting surface of the display unit 6 or on one side surface of the first optical element 1. The polarizing element 7 is a linear polarizing film or a circular polarizing film, and its function is to change the polarization state of the light emitted from the display unit 6.
[0038] The second optical element 2 is disposed on the transmitted light path of the first optical element 1. The second optical element 2 is a prism structure, which is a triangular prism structure in this embodiment. Its upper surface faces the first optical element 1, and its front surface is provided with a first quarter-wave plate 21 and an AR anti-reflection film 22 in sequence. Its rear surface is an inclined surface that slopes from top to bottom and forward.
[0039] Since the refractive index of the first quarter-wave plate 21 is the same as or similar to that of the second optical element 2, light will not be reflected when it reaches the front surface of the second optical element 2. If the refractive index of the second optical element 2 is n, then the refractive index of the first quarter-wave plate 21 can be selected as 0.9n to 1.1n.
[0040] The AR antireflective coating 22 is a special coating layer that enables light rays with an incident angle greater than or equal to 40° to be reflected by the AR antireflective coating 22, while light rays with an incident angle less than or equal to 25° can be transmitted through the AR antireflective coating 22.
[0041] The upper, front, and rear surfaces of the second optical element 2 can be processed into planar, spherical, aspherical, or freeform surfaces.
[0042] The third optical element 3 is disposed in front of the second optical element 2. The third optical element 3 is a reflective lens or a group of reflective lenses, and its function is to reflect the light transmitted from the AR anti-reflection film 22 of the second optical element 2 and reaching the third optical element 3.
[0043] When light is incident on the AR antireflection film 22 from the direction of the third optical element 3, light with an incident angle of less than or equal to 25° can pass through the AR antireflection film 22 and enter the first quarter-wave plate 21.
[0044] The fourth optical element 4 is disposed on the rear side of the second optical element 2. The fourth optical element 4 is a prism structure, which is a triangular prism structure in this embodiment. Its front surface is an inclined surface that slopes from top to bottom and forward. The front surface of the fourth optical element 4 corresponds to the rear surface of the second optical element 2. A polarizing beam splitter 41 is also provided between the front surface of the fourth optical element 4 and the rear surface of the second optical element 2. A polarizing reflective film 42 and a second quarter-wave plate 43 are sequentially provided on the rear surface of the fourth optical element 4.
[0045] The fourth optical element 4 is a compensation lens, which is used to compensate for the optical path and reduce the distortion when viewing the outside world.
[0046] The two side surfaces of the polarization beam splitter 41 are respectively bonded, glued or otherwise combined with the rear surface of the second optical element 2 and the front surface of the fourth optical element 4.
[0047] The function of the polarization beam splitter 41 is to perform transmission and reflection beam splitting, phase control, and stray light absorption.
[0048] The polarization beam splitter 41 can be a polarization beam splitter, a polarization reflector, a composite film made of a linear polarizer and a polarization reflector, a composite film made of a linear polarizer, a polarization reflector and a phase retardation film, or a composite film made of a linear polarizer, a phase retardation film and a reflective film, depending on the requirements.
[0049] The upper, front, and rear surfaces of the fourth optical element 4 can be processed into planar, spherical, aspherical, or freeform surfaces.
[0050] The fifth optical element 5 is disposed on the rear side of the fourth optical element 4, and a semi-transparent and semi-reflective film 51 is provided on the side of the fifth optical element 5 away from the fourth optical element 4.
[0051] The fifth optical element 5 is a transmission mirror, which adjusts the image quality and adjusts the incident light rays that are nearly parallel in each field of view into outgoing light rays at a large angle, thereby achieving a large field of view.
[0052] It should be noted that the dashed arrows in the diagram represent the propagation path of the imaging light rays.
[0053] The imaging principle of the optical system provided in this embodiment is as follows:
[0054] The light emitted from display unit 6 is converted into linearly polarized light by polarizing element 7, then enters the first optical element 1, is processed, and is transmitted out. The light transmitted from the first optical element 1 enters the interior of the second optical element 2 from its upper surface, propagates inside, reaches its front surface for the first time, and is transmitted out. After being processed into circularly polarized light by the first quarter-wave plate 21, it reaches the AR anti-reflection film 22 and is reflected for the first time. The light reflected from the first quarter-wave plate 21 becomes orthogonally linearly polarized light and enters the second optical element 2. It then propagates inside the second optical element 2, reaches its rear surface, and is transmitted out to the polarizing beam splitter 41. It is reflected a second time at the polarizing beam splitter 41, and the reflected light enters the interior of the second optical element 2 from its rear surface. It then propagates inside the second optical element 2, reaches its front surface, passes through the first quarter-wave plate 21 and the AR anti-reflection film 22, and is transmitted out to the third optical element 3. It is reflected a third time by the third optical element 3. The reflected light passes sequentially through the AR antireflection film 22 and the first quarter-wave plate 21, then enters the interior of the first optical element 1 from the front surface of the first optical element 1, propagates inside the first optical element 1 to its rear surface, and then is transmitted out from the rear surface of the first optical element 1 into the polarizing beam splitter 41, and then is transmitted out from the polarizing beam splitter 41 into the fourth optical element 4. The light propagates inside the fourth optical element 4 towards its rear surface, and then is transmitted out from the rear surface of the fourth optical element 4, passing sequentially through the polarizing reflection film 42 and the second quarter-wave plate 43 into the fifth optical element 5. Then it is reflected for the fourth time at the semi-transparent and semi-reflective film 51 on the rear surface of the fifth optical element 5. The light reflected at the semi-transparent and semi-reflective film passes sequentially through the fifth optical element 5 and the second quarter-wave plate 43 to the polarizing reflection film 42, and is reflected for the fifth time on the polarizing reflection film 42. The light reflected for the fifth time passes sequentially through the second quarter-wave plate 43 and the fifth optical element 5, and then is transmitted out from the semi-transparent and semi-reflective film 51 on the rear surface of the fifth optical element 5 to reach the human eye, forming a virtual image with a specific magnification.
[0055] This invention also analyzes imaging distortion using the following design parameters:
[0056] The display unit 6 has a screen size of 0.44 mm, a design eyelid of 14 mm, an eyebox of 12 × 6 mm, and a field of view (FOV) of 46.4°. The final image shows a maximum TV distortion of 5.26% at the center (EB) and 5.713% at the edge (EB). Example 2
[0057] Embodiment 2 of the present invention also provides a head-mounted display device, including wearable components and an optical module.
[0058] It should be noted that the optical path system in this embodiment can adopt the optical module in Embodiment 1. Its structure, working principle and technical effects are the same as those in Embodiment 1, and will not be repeated here.
[0059] The optical module is mounted on the wearable component. This wearable component can be a helmet or eyeglass frame, making it convenient for people to wear on their heads. Of course, the head-mounted display also includes a control unit and a storage unit; the control unit is used to control the device, and the storage unit is used to store images, videos, etc.
[0060] It should be noted that this application does not limit the application of the optical module to head-mounted display devices. The module can also be used in other devices. In one possible application scenario, it can also be integrated into desktop optical display devices and automotive optical display devices. Its virtual image distance is relatively far, which can realize eye protection function and improve the viewing experience.
[0061] This utility model is not limited to the optional embodiments described above, and anyone can derive other various forms of products under the guidance of this utility model. The specific embodiments described above should not be construed as limiting the scope of protection of this utility model. The scope of protection of this utility model shall be determined by the claims, and the description can be used to interpret the claims.
Claims
1. An optical module for reducing distortion, characterized in that: It includes a display unit, a first optical element, a second optical element, a third optical element, a fourth optical element, and a fifth optical element; The first optical element is disposed in the light-emitting path of the display unit; The second optical element is disposed on the transmitted light path of the first optical element. The second optical element is a prism structure with its upper surface facing the first optical element. A first quarter-wave plate and an AR anti-reflection film are sequentially disposed on its front surface, and its rear surface is an inclined surface that slopes from top to bottom and forward. The third optical element is disposed in front of the second optical element; The fourth optical element is disposed on the rear side of the second optical element. The fourth optical element has a prism structure, and its front surface is an inclined surface that slopes from top to bottom and corresponds to the rear surface of the second optical element. A polarizing beam splitter is provided between the front surface of the fourth optical element and the rear surface of the second optical element. A polarizing reflective film and a second quarter-wave plate are provided sequentially on the rear surface of the fourth optical element. The fifth optical element is disposed on the rear side of the fourth optical element, and a semi-transparent and semi-reflective film is provided on the side of the fifth optical element away from the fourth optical element.
2. The distortion-reducing optical module according to claim 1, characterized in that: The AR antireflective film is used to reflect light with an incident angle greater than or equal to 40° and to transmit light with an incident angle less than or equal to 25°.
3. The distortion-reducing optical module according to claim 1, characterized in that: A polarizer is provided between the display unit and the first optical element.
4. The distortion-reducing optical module according to claim 1, characterized in that: The first optical element is a transmission mirror.
5. The distortion-reducing optical module according to claim 1, characterized in that: The third optical element is a reflector.
6. The distortion-reducing optical module according to claim 1, characterized in that: The polarization beam splitter is a composite functional film layer composed of one or more of the following: polarizing reflector, linear polarizer, quarter-wave plate, half-wave plate, and reflective film layer.
7. The distortion-reducing optical module according to claim 1, characterized in that: The fifth optical element is a transmission mirror.
8. The distortion-reducing optical module according to claim 1, characterized in that: The optical surfaces of the first optical element and the second optical element are planes, spheres, aspherical surfaces, or freeform surfaces.
9. The distortion-reducing optical module according to claim 1, characterized in that: The optical surface of the fifth optical element is either a plane or a curved surface.
10. A head-mounted display device, characterized in that: It includes a wearable component and a distortion-reducing optical module as described in any one of claims 1-9, the optical module being disposed on the wearable component.