AR optical module and head-mounted display device

Abstract

The embodiment of the invention discloses an AR optical module and a head-mounted display device. Wherein the AR optical module comprises a first lens and a second lens which are arranged along a first optical axis, and the first lens comprises a first surface, a second surface and a third surface; the AR optical module further comprises a liquid lens and a display screen which are arranged along a second optical axis, the liquid lens and the display screen are located on one side of the first surface, the display screen is configured to be capable of moving along the second optical axis relative to the liquid lens, and the liquid lens and the display screen are used for displaying the liquid lens according to the diopter of a user. Adjusting the focal length of the AR optical module; the second lens is located on one side of the second surface, and a polarization reflector is arranged between the second lens and the first lens.

Description

Technical Field

[0001] The present application belongs to the field of optical display technology. Specifically, the present application relates to an AR optical module and a head-mounted display device. Background Art

[0002] In the existing field of AR (augmented reality) technology, traditional AR optical modules generally face a significant technical limitation, namely the lack of a flexible diopter adjustment mechanism. This deficiency directly leads to the fact that myopic or hyperopic users must wear glasses to correct their vision when using AR devices, which undoubtedly increases the user's wearing burden. More importantly, this multi-level visual correction method may introduce additional optical errors, such as increased aberrations, limited field of view, and image distortion, which in turn has an adverse effect on the overall display effect of the AR device and the user's visual comfort. Summary of the invention

[0003] The purpose of this application is to provide a new technical solution for an AR optical module and a head-mounted display device.

[0004] According to a first aspect of the present application, an embodiment of the present application provides an AR optical module, the AR optical module comprising a first lens and a second lens arranged along a first optical axis, wherein the first lens comprises a first surface, a second surface and a third surface;

[0005] The AR optical module further includes a liquid lens and a display screen arranged along a second optical axis, and the liquid lens and the display screen are located on one side of the first surface, and the display screen is configured to be movable along the second optical axis relative to the liquid lens, and the liquid lens and the display screen are used to adjust the focal length of the AR optical module according to the user's vision;

[0006] The second lens is located on one side of the second surface, and a polarizing reflector is arranged between the second lens and the first lens.

[0007] Optionally, the AR optical module further includes a polarizer, which is disposed on the light-emitting surface of the display screen and is used to convert the light emitted by the display screen into linearly polarized light.

[0008] Optionally, the incident light is folded twice in the first lens, thereby passing through the first lens three times, the focal length of the light passing through the first lens three times is L1, the focal length of the AR optical module is L, and 0.8≤L1 / L≤1.2.

[0009] Optionally, the first surface, the second surface and the third surface are free-form surfaces.

[0010] Optionally, the second surface is a surface of the first lens away from the aperture, the second surface is bent toward the aperture, and a radius of curvature of the second surface is -200 mm to -50 mm.

[0011] Optionally, the polarized reflector is arranged on the second surface;

[0012] The third surface is a surface of the first lens close to the aperture, and the third surface is a total reflection surface.

[0013] Optionally, the focal length of the liquid lens is L3, 40mm≤L3≤80mm, and the moving distance of the display screen along the second optical axis is A, 0mm≤|A|≤3mm.

[0014] Optionally, the first lens and the second lens are glued together to form a glued lens set, and the transmitted light focal length of the glued lens is 0.

[0015] Optionally, a surface of the second lens facing away from the first lens has the same surface shape as the third surface, wherein the third surface is the surface of the first lens close to the aperture.

[0016] Optionally, the transmission axis of the polarizer is perpendicular to the transmission axis of the polarizing reflector.

[0017] According to a second aspect of the present application, an embodiment of the present application provides a head-mounted display device, the head-mounted display device comprising:

[0018] casing; and

[0019] An AR optical module as described in the first aspect.

[0020] One beneficial effect of the embodiments of the present application is:

[0021] The embodiment of the present application provides a new AR optical module design, which has the characteristics of simple structure, high imaging clarity and adjustable diopter. Specifically, the AR optical module of the present application realizes adaptive adjustment for users with different myopia through the design of liquid lens and movable display screen, which greatly improves the applicability and user experience of AR equipment.

[0022] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments of the present application with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.

[0024] Figure 1A schematic diagram of the structure of an AR optical module provided in an embodiment of the present application;

[0025] Figure 2 One of the MTF diagrams of the AR optical module provided in the embodiment of the present application;

[0026] Figure 3 The second MTF diagram of the AR optical module provided in the embodiment of the present application;

[0027] Figure 4 This is the third MTF diagram of the AR optical module provided in an embodiment of the present application.

[0028] Description of reference numerals:

[0029] 1. First optical axis; 2. Aperture; 3. First lens; 31. First surface; 32. Second surface; 33. Third surface; 4. Display screen; 5. Light; 6. Second lens; 7. Polarizing reflector; 8. Polarizer; 9. Liquid lens. DETAILED DESCRIPTION

[0030] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0031] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present application, its application, or uses.

[0032] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0033] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0034] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0035] The AR optical module and head-mounted display device provided in the embodiments of the present application are described in detail below in conjunction with the accompanying drawings.

[0036] According to an embodiment of the present application, an AR optical module is provided. Figure 1The AR optical module includes a first lens 3 and a second lens 6 arranged along a first optical axis 1, wherein the first lens 3 includes a first surface 31, a second surface 32 and a third surface 33; the AR optical module also includes a liquid lens 9 and a display screen 4 arranged along the second optical axis, and the liquid lens 9 and the display screen 4 are located on one side of the first surface 31, and the display screen 4 is configured to be movable along the second optical axis relative to the liquid lens 9, and the liquid lens 9 and the display screen 4 are used to adjust the focal length of the AR optical module according to the user's vision; the second lens 6 is located on one side of the second surface 32, and a polarizing reflector 7 is arranged between the second lens 6 and the first lens 3.

[0037] The AR optical module provided in the embodiment of the present application mainly includes the following key components.

[0038] First lens 3: The first lens 3 has at least three surfaces, see Figure 1 , namely a first surface 31, a second surface 32 and a third surface 33; wherein the third surface 33 (the side away from the aperture 2) is, for example, a free-form surface and bends toward the aperture 2, which helps to compress the volume of the AR optical module.

[0039] The first lens 3 is used to participate in the transmission and folding of light, display the virtual image at a specific distance, and perform multiple reflections and transmissions of light through its surface to achieve a clear imaging effect.

[0040] The second lens 6 : the second lens 6 is located on one side of the second surface 32 of the first lens 3 in the entire optical structure, and a polarizing reflector 7 is disposed between the second lens 6 and the first lens 3 .

[0041] Polarized reflector 7: Polarized reflector 7 is disposed between first lens 3 and second lens 6. Polarized reflector 7 is used to reflect light, and cooperates with the total reflection surface (third surface 33) of first lens 3 to realize folding and transmission of light, thereby improving energy utilization of virtual optical path.

[0042] Liquid lens 9: see Figure 1 The liquid lens 9 is arranged along another optical axis, namely the second optical axis, and is located on one side of the first surface 31 of the first lens 3 (which is the light incident surface of the first lens 3 ).

[0043] Display screen 4: Also located on one side of the first surface 31 of the first lens 3, it is adjacent to the liquid lens 9 and arranged along the second optical axis. Display screen 4 is used to display images, and the light emitted by it should be linearly polarized light, otherwise it is necessary to process the light emitted by it and convert it into linearly polarized light. Then the linearly polarized light is folded and transmitted through the liquid lens 9 and the first lens 3.

[0044] The present application introduces a dynamic adjustment mechanism of the liquid lens 9 and the display screen 4, which can realize a personalized diopter adjustment function based on the user's myopia. The liquid lens 9 is an advanced adjustable focus element, and its focal length can be flexibly adjusted to meet the needs of users with different vision conditions. At the same time, the display screen 4 is designed to move forward and backward in a direction perpendicular to its surface, which further enhances the accuracy of focal length adjustment.

[0045] When a user wears the AR optical module of the present application for visual experience, the system including the AR optical module, such as the AR system, first identifies and records the user's myopia degree; then, by precisely controlling the focal length change of the liquid lens 9 and the front and rear position adjustment of the display screen 4, the AR optical module can present a clear, distortion-free image to the user in real time. In this process, the focal length of the liquid lens 9 is intelligently adjusted according to the user's myopia degree, and the fine adjustment of the display screen 4 ensures the optimal focus state of the image, thereby realizing personalized diopter adjustment.

[0046] This design not only greatly improves the applicability and user experience of the AR optical module, but also breaks the limitations of the traditional AR optical module in terms of vision adaptability. Users with different vision can get a clear visual experience through the AR optical module of this application.

[0047] It should be noted that the first lens 3 and the second lens 6 are arranged in series along the first optical axis 1, the liquid lens 9 and the display screen 4 are arranged in series along the second optical axis, and the first optical axis 1 and the second optical axis form a certain angle.

[0048] The AR optical module provided in the embodiment of the present application is shown in FIG. Figure 1 When the display screen 4 emits light, the light is first converted into linear polarized light, and then passes through the liquid lens 9 to enter the first lens 3. In the first lens 3, the light is folded twice and passes through the first lens 3 three times, and finally undergoes total reflection on the third surface 33 of the first lens 3, and is reflected back to the first lens 3 by the polarizing reflector 7, and finally enters the aperture 2 (or the human eye). By adjusting the focal length of the liquid lens 9 and the front and rear positions of the display screen 4, clear imaging can be achieved for users with different myopia degrees.

[0049] The AR optical module provided in the embodiment of the present application has a liquid lens 9 disposed on the light-emitting side of the display screen 4. The liquid lens 9 can adapt to the myopia or hyperopia of different users by virtue of its dynamic adjustment capability, adjust the focal length of the module in real time, and achieve diopter matching. This feature avoids the inconvenience of users having to wear extra glasses.

[0050] The focal length adjustment function of the liquid lens 9 forms a coordinated effect with the display screen 4 and the first lens 3 (whose unique three-surface design is particularly critical), ensuring that the light can be optimally processed at each stage of the propagation path, which not only improves the transmittance of the light, but also helps to reduce aberrations and distortions, thereby ensuring excellent image quality.

[0051] The AR optical module provided in the embodiment of the present application has achieved diversified functions and optimized structural design to maintain overall compactness and meet the needs of portable devices.

[0052] In some examples of this application, see Figure 1 The AR optical module also includes a polarizer 8, which is arranged on the light-emitting surface of the display screen 4 and is used to convert the light emitted by the display screen 4 into linearly polarized light.

[0053] According to this example of the present application, a polarizer 8 is also introduced into the AR optical module, and the function of the polarizer 8 is to convert the natural light emitted by the display screen 4 into linearly polarized light. This conversion step is critical in the AR optical module because it enables subsequent optical elements (such as liquid lens 9, first lens 3, etc.) to process and utilize these lights more effectively. When linearly polarized light passes through polarization-sensitive elements such as polarizing reflector 7, it can reduce light scattering and loss, thereby improving the utilization rate of light and the clarity of imaging.

[0054] In the present application, the introduction of the polarizer 8 can also enhance the fusion effect of virtual and real images. Specifically, in AR (augmented reality) applications, good fusion of virtual images and real images is crucial. The polarizer 8 converts the light of the display screen 4 into linear polarized light, and cooperates with other components in the AR optical module to better control the propagation direction and intensity of the light, thereby achieving a natural transition and fusion between virtual images and real scenes, and improving user experience.

[0055] It should be noted that natural light contains light of various directions and wavelengths. If these lights are not processed and directly irradiated into the human eye or optical module, glare or interference may occur. In this application, a polarizer 8 is introduced, which effectively reduces the interference of light in other directions by selectively transmitting light in a specific direction (i.e., linearly polarized light), thereby improving the anti-interference ability and stability of the AR optical module.

[0056] In some examples of this application, see Figure 1 The incident light is folded twice in the first lens 3, and thus passes through the first lens 3 three times. The focal length of the light passing through the first lens 3 three times is L1, and the focal length of the AR optical module is L, 0.8≤L1 / L≤1.2.

[0057] According to this example of the present application, see Figure 1 , the incident light first passes through the first surface 31 of the first lens 3 and then enters its third surface 33, and then reflects from the third surface 33 to the second surface 32, and then passes through the first lens 3 again after being reflected by the polarizing reflector 7 on one side of the second surface 32, and then exits to the aperture 2 (that is, the human eye) through the third surface 33. This means that after the light is emitted from the display screen 4, it is reflected twice inside the first lens 3 before entering the aperture 2 (human eye), thereby forming a folded path for the light. This design helps to reduce the volume of the AR optical module while ensuring that the light can be transmitted to the user's eyes along a predetermined path and ensuring imaging quality.

[0058] According to this example of the present application, see Figure 1 , the light emitted by the display screen 4 needs to pass through the first lens 3 three times during the transmission process. This is because after the light is reflected inside the first lens 3, it needs to pass through the first lens 3 again to reach the human eye. This design can achieve specific optical effects such as increasing the viewing angle, adjusting the direction of light or improving the imaging quality.

[0059] According to this example of the present application, the ratio of the focal length of the incident light passing through the first lens 3 three times to the focal length of the AR light module is in the range of 0.8 to 1.2 (including the two endpoint values ​​of 0.8 and 1.2). This ratio describes the influence of the focal length of the first lens 3 during the light transmission process on the focal length of the entire AR optical module. Specifically, it refers to the ratio between the total focal length of the light passing through the first lens 3 three times and the focal length of the AR optical module. This ratio ranges from 0.8 to 1.2, which means that the focal length of the first lens 3 occupies a relatively important proportion in the focal length of the AR optical module. At the same time, this ratio is also controlled within a reasonable range to ensure the overall optical performance and imaging quality.

[0060] According to the ratio range design in this example of the present application, at least the following technical effects can be achieved:

[0061] (1) Reduce the size of the AR optical module:

[0062] The design that the light is folded twice and transmitted three times in the first lens 3 enables the AR optical module to reduce the overall volume while maintaining the imaging quality. This is particularly important for AR devices that pursue portability and lightweight.

[0063] (2) Optimize imaging quality:

[0064] The light propagation path and imaging quality can be optimized by precisely controlling the number of times the light is folded and transmitted in the first lens 3, as well as the range of the focal ratio L1 / L. In this specific focal ratio range, the light propagates more stably in the first lens 3, reducing aberrations and distortions, thereby improving the clarity and accuracy of imaging.

[0065] It should be noted that although this design itself does not directly involve the vision adjustment function, it can be used in conjunction with components such as the liquid lens 9 to achieve clear imaging for users with different vision. The liquid lens 9 adjusts the focal length according to the user's vision, and the folding and transmission design of the light in the first lens 3 ensures the stability and clarity of the light during transmission. The combination of the two improves the applicability and user experience of the AR optical module.

[0066] In some examples of the present application, the first surface 31 , the second surface 32 , and the third surface 33 are free-form surfaces.

[0067] Designing the three surfaces of the first lens 3 as free-form surfaces is a technical highlight of this application. This design not only improves the imaging quality and the flexibility of the optical path design, but also adapts to the needs of different application scenarios and improves the user experience. The specific analysis is as follows:

[0068] Free-form surfaces have a higher degree of design freedom than traditional spherical or aspherical lenses, and can more accurately control the light path and reduce aberrations and distortions. In the present application, the three surfaces of the first lens 3 are all free-form surfaces, so that the first lens 3 can better control the propagation of light, thereby improving the clarity and sharpness of the image. This is crucial for AR optical modules because it is directly related to the quality of the image seen by the user.

[0069] The design of the free-form surface makes the optical path design more flexible and precise. By adjusting the parameters of the free-form surface (such as the radius of curvature, surface shape, etc.), the light transmission path can be optimized to achieve more complex optical functions. In the present application, this design helps to achieve the folding and multiple transmission of light in the first lens 3, thereby reducing the volume of the AR optical module and improving the imaging quality.

[0070] High-quality imaging and optimized optical path design directly enhance the user's visual experience when using AR devices. Users can see clearer and more stable images. In addition, free-form lenses may also help reduce problems such as glare and ghosting, further improving user comfort.

[0071] In some examples of this application, see Figure 1The second surface 32 is the surface of the first lens 3 away from the aperture 2, the second surface 32 is bent toward the aperture 2, and the curvature radius of the second surface 32 is -200 mm to -50 mm.

[0072] The second surface 32 of the first lens 3 is designed to be curved toward the aperture 2, and its radius of curvature is designed to be in the range of -200 mm to -50 mm. This design helps to reduce the volume of the AR optical module.

[0073] Since the bending direction of the second surface 32 of the first lens 3 is opposite to the line of sight of the human eye, the propagation path of light inside the lens is more compact, thereby realizing the miniaturization and lightness of the AR optical module. This is of great significance for improving the portability and wearing comfort of AR devices.

[0074] Specifically, when the third surface 33 of the first lens 3 is bent toward the aperture 2 (actually the direction of the human eye), it can reduce the thickness of the first lens 3 (the thickness along the first optical axis) while maintaining the necessary optical performance, thereby effectively compressing the volume of the entire AR optical module. This is crucial for AR devices that pursue lightness and portability. The free-form surface that bends toward the aperture 2 (human eye) can better guide light into the human eye, reduce the transmission distance and number of reflections of light inside the AR optical module, reduce light loss, and improve light path efficiency.

[0075] In addition, the free-form surface that bends toward the human eye also helps to expand the field of view of the AR optical module, allowing users to observe a wider virtual image.

[0076] In this example of the present application, by precisely controlling the radius of curvature of the second surface 32 of the first lens 3, the refraction and reflection paths of the light can be optimized, the loss and distortion of the light can be reduced, and the imaging effect can be improved. This design makes the light more evenly distributed inside the first lens 3, reducing problems such as light intensity attenuation and imaging blur caused by the long light propagation path. In addition, the specific curvature design of the second surface 32 also helps to enhance the stability of the entire AR optical module.

[0077] For this example of the present application, although this design itself mainly focuses on optimizing the volume and imaging quality of the AR optical module, it can be combined with adjustment elements such as the liquid lens 9 to achieve adaptation to users with different vision. The liquid lens 9 is responsible for adjusting the focal length according to the user's diopter, while the precise design of the surface of the first lens 3 ensures the stability and clarity of the light during transmission. The two complement each other and improve the applicability and user experience of the AR optical module.

[0078] In some examples of this application, see Figure 1, the polarizing reflector 7 is arranged on the second surface 32; the third surface 33 is the surface of the first lens 3 close to the aperture 2, and the third surface 33 is a total reflection surface.

[0079] The light is totally reflected on the third surface 33 of the first lens 3 to the polarized reflector 7 provided on the second surface 32, and then re-transmitted through the first lens 3 after being reflected by the polarized reflector 7, and finally enters the aperture 2. In this process, the utilization rate of the light is significantly improved. The third surface 33 of the first lens 3 is a totally reflecting surface, and this design ensures that the light is reflected with almost no loss, while the polarized reflector 7 selectively reflects according to the polarization state of the light, further enhancing the utilization rate of the light. This design helps to improve the optical efficiency of the entire AR optical module and make the virtual image brighter and clearer.

[0080] For example, in this application, a 50% energy utilization rate of the virtual light path is achieved by combining the total reflection surface and the polarized reflector 7. By combining the total reflection surface and the polarized reflector 7, a high energy utilization rate of the virtual light path is achieved, and the overall performance of the AR optical module is improved.

[0081] The third surface 33 (total reflection surface) of the first lens 3 is combined with the polarizing reflector 7 provided on the second surface 32 to achieve multiple folding and reflection of the linearly polarized light emitted by the display screen 4. This design makes the optical path more compact, which is conducive to reducing the volume and weight of the AR optical module.

[0082] In the present application, the third surface 33 of the first lens 3 is designed as a total reflection surface, which ensures the stability and consistency of the light during the reflection process. At the same time, the introduction of the polarizing reflector 7 also increases the ability to control the polarization state of the light, which helps to reduce the interference and distortion caused by the mismatch of the polarization state of the light. These measures together improve the imaging quality and make the image clearer.

[0083] In some examples of the present application, the focal length of the liquid lens 9 is L3, 40 mm ≤ L3 ≤ 80 mm, and the moving distance A of the display screen 4 along the second optical axis 10 is 0 mm ≤ |A| ≤ 3 mm.

[0084] The parameter settings of the focal length of the liquid lens 9 (denoted as L3) and the moving distance A of the display screen 4 along the second optical axis 10 reflect the consideration of user adaptability. Specifically, the focal length L3 of the liquid lens 9 is set at 40mm to 80mm (including the two endpoints of 40mm and 80mm), which can fully cover the myopia adjustment needs of most users (the diopter of general users is between -5D and 0D). At the same time, the moving distance A of the display screen 4 is limited to ±3mm, ensuring that when the focal length is adjusted to adapt to different users, the image can still maintain high clarity and stability.

[0085] According to the AR optical module provided in the embodiment of the present application, by adjusting the focal length L3 of the liquid lens 9, the AR optical module can adapt to the myopia or hyperopia of different users in real time to provide clear imaging. The limitation of the moving distance A of the display screen 4 reduces the imaging jitter and blur caused by the change of the display screen position. Fine-tuning the position of the display screen 4 within a limited range can further optimize the optical path and ensure that the light remains stable during transmission, thereby reducing aberrations and distortions and improving imaging quality.

[0086] Users can clearly view virtual images through the AR optical module provided in this application without wearing additional glasses, which greatly improves the convenience and comfort of use.

[0087] In addition, the focal length of the liquid lens 9 and the position of the display screen 4 can have an automatic adjustment function, which also eliminates the need for users to perform cumbersome manual adjustments during use, further enhancing the user experience.

[0088] In some examples of this application, see Figure 1 The first lens 3 and the second lens 6 are glued together to form a glued lens group, and the focal length of the glued lens through which light is transmitted is 0.

[0089] In the AR optical module provided by the present application, the first lens 3 and the second lens 6 form a cemented lens group. The design focus of this cemented lens group is that its transmitted light focal length is 0, which means that the cemented lens group does not produce additional convergence or divergence effects on the passing light, thereby maintaining the original path and characteristics of the light. In addition, the design of the cemented lens group helps to reduce aberrations introduced by a single lens, such as spherical aberration, coma, etc.

[0090] It should be noted that, since the transmitted light focal length of the cemented lens group composed of the first lens 3 and the second lens 6 is 0, it will not produce additional focusing or diverging effects on the light, thereby avoiding the aberration problem caused by the mismatch of the lens focal length. This helps to improve the clarity of the AR optical module when displaying images, so that users can get a more realistic visual experience.

[0091] The design of the glued lens group reduces the number of components in the AR optical module and reduces the imaging quality problems caused by loose or misaligned components. At the same time, the tight bonding of the glued surface also helps to improve the stability and reliability of the entire AR optical module.

[0092] In addition, the bonding design of the first lens 3 and the second lens 6 can also simplify the structure of the AR optical module, which is beneficial to the assembly of the AR optical module.

[0093] In the AR optical module provided in the present application, the second lens 6 is glued to the first lens 3 to form a glued lens group, and the focal length of the glued lens through which light is transmitted is 0, which helps to improve the overall imaging quality; at the same time, the bonding surface shape of the second lens 6 and the first lens 3 is matched to ensure the stability of light transmission.

[0094] In some examples of the present application, a surface of the second lens 6 facing away from the first lens 3 has the same surface shape as the third surface 33 , and the third surface 33 is the surface of the first lens 3 close to the aperture 2 .

[0095] The second lens 6 matches the first lens 3 on a specific surface, which means that the two surfaces are consistent in shape and curvature. This design helps to reduce light scattering and aberration caused by surface mismatch, thereby improving the imaging quality of the AR optical module.

[0096] When light enters the second lens 6 from the first lens 3, due to the similarity of the surface shapes, the light can transition more smoothly, reducing light loss and imaging distortion caused by sudden changes in surface shapes.

[0097] In some examples of the present application, the transmission axis of the polarizer 8 is perpendicular to the transmission axis of the polarizing reflector 7 .

[0098] The polarizer 8 and the polarization reflector 7 are both elements for controlling the direction of polarized light. The polarizer 8 allows polarized light in a specific direction to pass through, while blocking polarized light in other directions. The polarization reflector 7 reflects polarized light in a specific direction.

[0099] The polarizer 8 is, for example, a polarizing film, and the polarizing reflector 7 is, for example, a polarizing reflective film.

[0100] The transmission axis of the polarizer 8 and the transmission axis of the polarizing reflector 7 are designed to be perpendicular, which means that after the light emitted from the display screen 4 passes through the polarizer 8 and becomes linearly polarized light, its polarization direction will be perpendicular to the reflection direction of the polarizing reflector 7. This design can ensure that the light maintains efficient polarization state control during the subsequent transmission process.

[0101] When light passes through the polarizer 8 and enters the polarized reflector 7 with a specific polarization direction, most of the light can be reflected back into the AR optical module as expected, thereby achieving efficient light energy utilization.

[0102] The AR optical module of the present application is described below through a specific example.

[0103] For a specific example, see Figure 1 The AR optical module includes a first lens 3 and a second lens 6 arranged along a first optical axis 1, wherein the first lens 3 includes a first surface 31, a second surface 32 and a third surface 33, and the first surface 31, the second surface 32 and the third surface 33 are all free-form surfaces, the second surface 32 of the first lens 3 is glued to the second lens, and a polarizing reflector 7 is provided on the glued surface of the two; the second surface 32 is bent toward the aperture 2; the third surface 33 is a total reflection surface;

[0104] The first lens 3 and the second lens 6 are glued together to form a glued lens set, and the transmitted light focal length of the glued lens is 0; the surface of the second lens 6 facing away from the first lens 3 is the same as the surface shape of the third surface 33;

[0105] The incident light is folded twice in the first lens 3, and thus passes through the first lens 3 three times. The focal length of the light passing through the first lens 3 three times is L1, the focal length of the AR optical module is L, and 0.8≤L1 / L≤1.2;

[0106] The AR optical module further includes a liquid lens 9 and a display screen 4 arranged along the second optical axis. The liquid lens 9 and the display screen 4 are located on one side of the first surface 31. A polarizer 8 is arranged on the light-emitting surface of the display screen 4. The display screen 4 can move along the second optical axis relative to the liquid lens 9. The liquid lens 9 and the display screen 4 are used to adjust the focal length of the AR optical module according to the user's vision.

[0107] The focal length of the liquid lens 9 is L3, 40 mm ≤ L3 ≤ 80 mm, and the moving distance of the display screen 4 along the second optical axis 10 is A, 0 mm ≤ |A| ≤ 3 mm;

[0108] The transmission axis of the polarizer 8 is perpendicular to the transmission axis of the polarizing reflector 7 .

[0109] Table 1 below shows the optical parameters of this specific example.

[0110] Table 1

[0111]

[0112] Figure 2 , Figure 3 , Figure 4 The modulation transfer function MTF curves of the AR optical module shown in this specific example at 450nm, 540nm, and 610nm are respectively Figures 2 to 4 It can be seen that:

[0113] At a spatial frequency of 15lp / mm and a wavelength of 450nm, the MTF value of the AR optical module is higher than 0.7; at a wavelength of 540nm, the value of the AR optical module is higher than 0.7; and at a wavelength of 610nm, the MTF of the AR optical module is higher than 0.7.

[0114] Specifically, the MTF value (modulation transfer function value) is an important indicator to measure the optical performance of AR optical modules. It reflects the module's ability to transmit image details (i.e. high-frequency information). The higher the MTF value, the stronger the module's ability to transmit image details and the better the imaging quality.

[0115] MTF value at 450nm wavelength: At 15lp / mm spatial frequency, the MTF value of the AR optical module is higher than 0.7. This shows that in the blue light region (450nm is close to the wavelength of blue light), the AR optical module can well transmit the high-frequency details of the image and has high imaging clarity.

[0116] MTF value at 540nm wavelength: At 15lp / mm spatial frequency, the MTF value of the AR optical module is higher than 0.7. In the green light region (540nm is within the green light wavelength range), the AR optical module maintains a high imaging quality, further verifying its excellent performance in a wide spectral range.

[0117] MTF value at 610nm wavelength: In the red light region (610nm is close to the wavelength of red light), the MTF value of the AR optical module at a spatial frequency of 15lp / mm is still higher than 0.7. This shows that the AR optical module can also effectively transmit the high-frequency information of the image in the red light band, ensuring the clarity and color reproduction of the full-color image.

[0118] In summary, Figures 2 to 4 The MTF curve analysis in the figure shows that the AR optical module has excellent imaging performance in the visible light range (especially at the three wavelengths of 450nm, 540nm, and 610nm), and can maintain a high MTF value at different wavelengths, thereby ensuring the clarity and color accuracy of the imaging. This is crucial for augmented reality (AR) applications, as it requires the AR optical module to accurately and clearly reproduce the fusion effect of virtual information and the real world.

[0119] According to another embodiment of the present application, a head mounted display device is provided, wherein the head mounted display device comprises a housing and the AR optical module as described above.

[0120] The head-mounted display device provided in the embodiments of the present application is, for example, AR smart glasses or an AR smart helmet.

[0121] The specific implementation of the head-mounted display device of the embodiment of the present application can refer to the above-mentioned AR optical module embodiments, so it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0122] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0123] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. An AR optical module, characterized in that: It comprises a first lens (3) and a second lens (6) arranged along a first optical axis (1), wherein the first lens (3) comprises a first surface (31), a second surface (32) and a third surface (33); The AR optical module further comprises a liquid lens (9) and a display screen (4) arranged along a second optical axis, wherein the liquid lens (9) and the display screen (4) are located on one side of the first surface (31), and the display screen (4) is configured to be movable along the second optical axis relative to the liquid lens (9), and the liquid lens (9) and the display screen (4) are used to adjust the focal length of the AR optical module according to the user's vision; The second lens (6) is located on one side of the second surface (32), and a polarizing reflector (7) is arranged between the second lens (6) and the first lens (3).

2. The AR optical module according to claim 1, characterized in that: The AR optical module further comprises a polarizer (8), which is arranged on the light-emitting surface of the display screen (4) and is used for converting the light emitted by the display screen (4) into linearly polarized light.

3. The AR optical module according to claim 2, characterized in that: The incident light is folded twice in the first lens (3), thereby passing through the first lens (3) three times, the focal length of the light passing through the first lens (3) three times is L1, the focal length of the AR optical module is L, and 0.8≤L1 / L≤1.

2.

4. The AR optical module according to claim 1, characterized in that: The first surface (31), the second surface (32) and the third surface (33) are free-form surfaces.

5. The AR optical module according to claim 4, characterized in that: The second surface (32) is the surface of the first lens (3) away from the aperture (2), the second surface (32) is bent toward the aperture (2), and the curvature radius of the second surface (32) is -200 mm to -50 mm.

6. The AR optical module according to claim 5, characterized in that: The polarizing reflector (7) is arranged on the second surface (32); The third surface (33) is a surface of the first lens (3) close to the aperture (2), and the third surface (33) is a total reflection surface.

7. The AR optical module according to claim 1, characterized in that: The focal length of the liquid lens (9) is L3, 40 mm ≤ L3 ≤ 80 mm, and the moving distance of the display screen (4) along the second optical axis (10) is A, 0 mm ≤ |A| ≤ 3 mm.

8. The AR optical module according to claim 1, characterized in that: The first lens (3) and the second lens (6) are glued together to form a glued lens set, and the transmitted light focal length of the glued lens is 0.

9. The AR optical module according to claim 8, characterized in that: The surface of the second lens (6) facing away from the first lens (3) has the same surface shape as the third surface (33), wherein the third surface (33) is the surface of the first lens (3) close to the aperture (2).

10. The AR optical module according to claim 2, characterized in that: The transmission axis of the polarizer (8) is perpendicular to the transmission axis of the polarizing reflector (7).

11. A head mounted display device, characterized in that: include: shell; and An AR optical module as described in any one of claims 1 to 10.

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