AR (Augmented Reality) optical module, imaging display method thereof and AR display equipment

Abstract

The embodiment of the invention provides an AR optical module, an imaging display method thereof and AR display equipment. The AR optical module comprises an optical prism assembly, a polarization optical assembly and a screen. Wherein the optical prism assembly comprises a first prism and a second prism which are glued along the same optical axis, and the first prism and the second prism are free-form surface prisms; the polarization optical assembly comprises a polarization reflection element and a first phase delayer which are arranged between the first prism and the second prism, and a light splitting element which is arranged on the side, deviating from the first prism, of the second prism, and the first phase delayer is located on a light path between the light splitting element and the polarization reflection element; the screen is located on the light incident side of the second prism, the central axis of the screen is perpendicular to the optical axis, virtual imaging light emitted by the screen penetrates through the second prism three times in total, and the folding thickness Ft of the virtual imaging light penetrating through the second prism three times and the total focal length F of the AR optical module meet the condition that Ft / F is larger than or equal to 1 and smaller than or equal to 4.

Description

Technical Field

[0001] This application relates to the field of augmented reality (AR) technology, and more specifically, to an AR optical module, an AR display device, and an imaging display method for an AR optical module. Background Technology

[0002] Traditional AR optical modules suffer from problems such as complex structure, small field of view (FOV), and high cost. Existing optical solutions typically require the combination of multiple optical elements to achieve optical path folding, resulting in excessively large module size and difficulties in aberration correction. Furthermore, existing polarization optical path designs suffer from low energy efficiency and severe stray light interference. Therefore, there is an urgent need to develop an AR optical solution that is compact, has high imaging quality, and optimizes light energy utilization. Summary of the Invention

[0003] The purpose of this application is to provide a new technical solution for an AR optical module, its imaging and display method, and an AR display device.

[0004] In a first aspect, this application provides an AR optical module. The AR optical module includes:

[0005] An optical prism assembly includes a first prism and a second prism bonded together along the same optical axis. Both the first prism and the second prism are freeform surface prisms. The optical prism assembly is used to transmit real ambient light and fold virtual imaging light from a screen.

[0006] A polarization optical component includes a polarization reflecting element and a first phase retarder disposed between a first prism and a second prism, and a beam splitting element disposed on the side of the second prism away from the first prism, wherein the first phase retarder is located in the optical path between the beam splitting element and the polarization reflecting element.

[0007] The screen, located on the light-incident side of the second prism, has its central axis perpendicular to the optical axis. The virtual imaging light emitted from the screen passes through the following paths in sequence:

[0008] After entering the second prism, it is reflected by the polarization reflection element and the first phase delayer to the beam splitter. After being reflected by the beam splitter, it passes through the second prism, enters the first prism, and finally exits.

[0009] The virtual imaging light rays pass through the second prism a total of three times, and the folding thickness F of the light rays passing through the second prism three times is... t The total focal length F of the AR optical module satisfies: 1 ≤ F t / F≤4.

[0010] Optionally, an aperture is provided along the optical axis on the side of the first prism opposite to the second prism;

[0011] The surfaces of the first prism near the aperture, the second prism away from the aperture, and the second prism near the screen are all freeform surfaces, and the radius of curvature R of each freeform surface is... i The ratio of the total focal length F of the AR optical module to the total focal length F of the AR optical module satisfies: -10 ≤ R i / F≤5.

[0012] Optionally, the ratio of the effective focal length F2 of the second prism to the total focal length F of the AR optical module satisfies: 0.1≤F2 / F≤7.

[0013] Optionally, the surface of the first prism near the aperture and the surface of the second prism away from the aperture are both freeform surfaces concave towards the aperture.

[0014] Optionally, the bonding interface between the first prism and the second prism has the same surface shape, and the surface of the second prism away from the aperture has the same surface shape as the surface of the first prism near the aperture. The optical prism assembly formed by bonding the first prism and the second prism has zero transmittance.

[0015] Optionally, the AR optical module further includes a first polarizing element, which is disposed on the surface of the first prism near the aperture, and its transmission axis is parallel to the transmission axis of the polarizing reflective element.

[0016] Optionally, the polarization reflection element and the first phase retarder are stacked at the cemented interface between the first prism and the second prism, and the beam splitting element is disposed on the surface of the second prism away from the aperture.

[0017] Optionally, the AR optical module further includes a second phase delayer and a second polarizing element, wherein the second phase delayer and the second polarizing element are stacked on the surface of the second prism away from the aperture.

[0018] Optionally, a third polarizing element and a third phase delayer are sequentially stacked on the light-emitting surface of the screen, and the third polarizing element is perpendicular to the transmission axis direction of the polarizing reflective element;

[0019] The virtual imaging light emitted from the screen passes sequentially through the third polarizing element and the third phase delayer, becoming circularly polarized light.

[0020] Secondly, this application provides an AR display device, the AR display device comprising:

[0021] The outer casing; and

[0022] The AR optical module as described in the first aspect.

[0023] Thirdly, this application provides an imaging display method for an AR optical module, the imaging display method comprising:

[0024] The screen displays a virtual image, and the virtual imaging light emitted by the screen is circularly polarized light;

[0025] The virtual imaging light is guided to a second prism on the side away from the aperture stop. After entering the second prism, the virtual imaging light is reflected by a first phase delayer and a polarization reflection element located on the side of the second prism near the aperture stop.

[0026] The reflected virtual imaging light is further guided to the beam splitter on the side of the second prism away from the aperture, and the beam splitter reflects the virtual imaging light again and makes it pass through the second prism and enter the first prism;

[0027] The virtual imaging light rays passing through the second prism are guided to the first prism, and enter the aperture through the first polarizing element located on the side of the first prism near the aperture, ultimately achieving image display;

[0028] The virtual imaging light rays pass through the second prism a total of three times, and its folding thickness F t The total focal length F of the AR optical module satisfies the following relationship: 1 ≤ F t / F≤4.

[0029] The beneficial effects of this application are as follows:

[0030] The AR optical module provided in this application embodiment achieves efficient superposition of virtual and real images through the combination of freeform prisms and polarization optical components, and brings the following significant beneficial effects:

[0031] Compact structure: The freeform prism design effectively reduces the size of the AR optical module, making it more portable and easier to integrate;

[0032] High-efficiency optical path: By combining optical prism components with polarization reflection elements, phase delayers and beam splitters, the utilization rate of light and display brightness are significantly improved, ensuring efficient optical path transmission;

[0033] Large field of view: The design of the freeform prism not only optimizes the light transmission path, but also expands the field of view of the AR optical module, providing users with a wider visual experience.

[0034] High imaging quality: At wavelengths of 450nm, 550nm and 610nm, the modulation transfer function (MTF) value of this AR optical module is greater than 0.6 at a spatial frequency of 15lp / mm, ensuring high-definition display effect and enhancing the user's visual experience.

[0035] In summary, the AR optical module of this application embodiment achieves multiple advantages such as compact structure, efficient optical path, large field of view and high imaging quality, bringing users an excellent visual experience.

[0036] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0037] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0038] Figure 1 A schematic diagram of an optical architecture for an AR optical module provided in an embodiment of this application;

[0039] Figure 2 This is a schematic diagram of the optical architecture of the AR optical module provided in Embodiment 1 of this application;

[0040] Figures 3a-3c They are respectively Figure 2 The diagram shows the modulation transfer function (MTF) curves of the AR optical module at wavelengths of 450nm, 550nm, and 610nm.

[0041] Figures 4a-4c They are respectively Figure 2 The distortion curves of the AR optical module at wavelengths of 450nm, 550nm, and 610nm are shown.

[0042] Figures 5a-5c They are respectively Figure 2 The dot array diagrams of the AR optical module at wavelengths of 450nm, 550nm and 610nm are shown.

[0043] Figure 6 This is a schematic diagram of the optical architecture of the AR optical module provided in Embodiment 2 of this application;

[0044] Figures 7a-7c They are respectively Figure 6 The diagram shows the modulation transfer function (MTF) curves of the AR optical module at wavelengths of 450nm, 550nm, and 610nm.

[0045] Figures 8a-8c They are respectively Figure 6The distortion curves of the AR optical module at wavelengths of 450nm, 550nm, and 610nm are shown.

[0046] Figures 9a-9c They are respectively Figure 6 The dot array diagram of the AR optical module at wavelengths of 450nm, 550nm and 610nm is shown.

[0047] Figure 10 This is a schematic diagram of the optical architecture of the AR optical module provided in Embodiment 3 of this application;

[0048] Figures 11a-11c They are respectively Figure 10 The diagram shows the modulation transfer function (MTF) curves of the AR optical module at wavelengths of 450nm, 550nm, and 610nm.

[0049] Figures 12a-12c They are respectively Figure 10 The distortion curves of the AR optical module at wavelengths of 450nm, 550nm, and 610nm are shown.

[0050] Figures 13a-13c They are respectively Figure 10 The diagram shows the dot array of the AR optical module at wavelengths of 450nm, 550nm, and 610nm.

[0051] Explanation of reference numerals in the attached figures:

[0052] 1. Optical axis; 2. Aperture; 3. First prism; 4. Second prism; 5. Screen; 6. Virtual imaging ray; 7. First polarizing element; 8. Polarizing reflection element; 9. First phase delayer; 10. Beam splitter; 11. Second phase delayer; 12. Second polarizing element; 13. Third polarizing element; 14. Third phase delayer. Detailed Implementation

[0053] 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, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0054] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0055] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0056] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0057] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0058] The AR optical module, its imaging and display method, and the AR display device provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0059] According to one embodiment of this application, an AR optical module is provided, see [link to relevant documentation]. Figure 1 The AR optical module includes an optical prism assembly, a polarizing optical assembly, and a screen 5. The optical prism assembly includes a first prism 3 and a second prism 4 bonded together along the same optical axis 1. Both the first prism 3 and the second prism 4 are freeform prisms. The optical prism assembly is used to transmit ambient light and fold virtual imaging light 6 from the screen 5. The polarizing optical assembly includes a polarizing reflective element 8 and a first phase delayer 9 disposed between the first prism 3 and the second prism 4, and a beam splitter 10 disposed on the side of the second prism 4 facing away from the first prism 3. The first phase delayer 9 is located in the optical path between the beam splitter 10 and the polarizing reflective element 8. The screen 5 is located on the light-incident side of the second prism 4, and its central axis is perpendicular to the optical axis 1. The virtual imaging light 6 emitted from the screen 5 passes through the following paths sequentially:

[0060] After entering the second prism 4, it is reflected by the polarization reflection element 8 and the first phase delayer 9 to the beam splitter 10. After being reflected by the beam splitter 10, it passes through the second prism 4, enters the first prism 3, and finally exits.

[0061] The virtual imaging ray 6 passes through the second prism 4 a total of three times, and its folding thickness F passes through the second prism 4 three times. t The total focal length F of the AR optical module satisfies: 1 ≤ F t / F≤4.

[0062] The AR optical module provided in this application embodiment is a design that achieves the superposition of virtual and real images by combining freeform prisms and polarizing optical elements. Specifically, the first prism 3 and the second prism 4 in the AR optical module provided in this application embodiment are paired with a series of optical films. They can not only efficiently transmit ambient light but also fold the virtual imaging light 6 emitted from the screen 5. See [link to relevant documentation]. Figure 1This allows these rays of light to be projected into the user's eyes to form an image. Through this series of optical processes, the AR optical module achieves the goal of integrating virtual information with the real environment, bringing users a good immersive visual experience.

[0063] The AR optical module provided in this application includes a specially designed optical prism assembly, which includes a first prism 3 and a second prism 4 glued together. Specifically, the first prism 3 and the second prism 4 are both freeform prisms, and they are glued together along the same optical axis 1. See [link to relevant documentation]. Figure 1 This allows light to travel along a predetermined path.

[0064] Based on the optical architecture design provided in this application embodiment, the first prism 3 and the second prism 4 are used to transmit ambient light and fold the virtual imaging light ray 6 from the screen 5. Specifically, the first prism 3 is mainly used to receive and transmit ambient light. The second prism 4 is used to fold the virtual imaging light ray 6, so that the virtual imaging light ray 6 can be reflected and propagated multiple times within the module.

[0065] By employing the freeform surface design of two prisms and their bonding, the AR optical module structure of this application achieves a significant reduction in size. It is more compact and lightweight compared to traditional optical architectures. The multiple folds of light within the second prism 4 ensure efficient superposition of virtual and real images, thereby providing users with a more realistic AR experience.

[0066] The optical axis 1 is the central axis of the light path propagation in the AR optical module provided in this application. The main optical elements (such as prisms, reflective elements, beam splitting elements, etc.) are arranged along the optical axis 1 in a specific order to ensure the collimation of the light path and the accurate propagation of the light.

[0067] In the design of the AR optical module provided in this application embodiment, a variety of optical films are also incorporated. Among them, the polarization reflection element 8, the first phase delayer 9, and the beam splitter 10 play important roles. They work together with the prism (especially the second prism 4) to achieve two folds in the optical path. The following is a detailed description of the functions of these three core optical films.

[0068] The polarization reflective element 8, a key optical component in the light path folding process, is positioned between the first prism 3 and the second prism 4 to reflect light with a specific polarization direction. The polarization reflective characteristics of the element 8 allow for precise control of the polarization direction and propagation path of the light. It is responsible for reflecting light with a specific polarization state, guiding it along a predetermined light path, and effectively filtering out interfering light such as stray light, thereby ensuring image clarity.

[0069] In the embodiments of this application, the polarization reflective element 8 is, for example, a polarization reflective film.

[0070] The first phase delayer 9 is mainly used to adjust the polarization state of light. It can change the phase of the light, ensuring that the reflected and refracted light maintains a consistent polarization direction. See [link to documentation] for details on how the first phase delayer 9 is adjusted. Figure 1 This ensures that the virtual imaging light 6 from screen 5 can still be accurately projected into the user's eyes after being folded multiple times (such as twice) inside the second prism 4, thus guaranteeing a high-quality visual experience.

[0071] In this application, the first phase delayer 9 is, for example, a quarter-wave plate.

[0072] The beam splitter 10 is key to achieving the overlay of virtual and real images. For example, it can split light into two paths: one for transmitting ambient light from the real world, and the other for carrying virtual imaging light. After being processed by the optical prism assembly and optical film, these two paths of light are ultimately merged in front of the user, providing a good AR visual experience.

[0073] In this application, the beam splitter 10 is, for example, a semi-transparent and semi-reflective film.

[0074] In this application, the polarization reflection element 8, the first phase delayer 9, and the beam splitter 10 work together with the two prisms to construct a highly efficient and stable optical path folding system, providing excellent optical performance and visual experience for the AR optical module.

[0075] The AR optical module provided in this embodiment also includes a screen 5, see [link]. Figure 1 The screen 5 is designed to be located on one side of the second prism 4, and the central axis of the screen 5 is perpendicular (or orthogonal) to the optical axis 1 of the optical prism assembly. The screen 5 can be used to display images, and the virtual imaging light 6 emitted by it, after being folded and reflected by the optical prism assembly and the optical film, finally enters the user's eye, that is, enters the aperture 2 (see Figure 1 The aperture 2 shown on the left side of the middle section.

[0076] The central axis of screen 5 refers to the axis that passes through the center of screen 5 and is perpendicular to the plane on which the screen is located.

[0077] According to the AR optical module provided in the embodiments of this application, see [link to relevant documentation]. Figure 1The virtual imaging light ray 6 emitted by the screen 5 will be folded twice within the second prism 4. During this process, the virtual imaging light ray 6 passes through the second prism 4 a total of three times, and the virtual imaging light ray passes through the second prism 4 three times with a folding thickness F. t The total focal length F of the AR optical module satisfies the following relationship: 1 ≤ F t / F≤4.

[0078] It should be noted that the virtual imaging ray 6 passes through the second prism 4 through a folded thickness F three times. t This refers to the effective path length accumulated by the virtual imaging ray 6 after entering the second prism 4 and sequentially undergoing the following three transmission (and accompanying reflection) processes:

[0079] See Figure 1 The virtual imaging ray 6 first enters the second prism 4 and is then reflected by the polarization reflection element 8 and the first phase delayer 9;

[0080] The reflected virtual imaging ray 6 will re-enter the second prism 4 and propagate to the beam splitter 10;

[0081] After being reflected by the beam splitter 10, the virtual imaging light 6 will pass through the second prism 4 for the third time and finally enter the first prism 3.

[0082] During these three transmission processes, the virtual imaging ray 6 is "folded" and propagates within the second prism 4 due to multiple reflections and transmissions, forming an effective path length longer than the straight-line distance, i.e., a folding thickness F. t The fold thickness F t There is a specific proportional relationship between the total focal length F of the AR optical module and the total focal length F of the AR optical module, i.e., 1 ≤ F. t / F≤4, this ratio is of great significance for optimizing the size and optical performance of AR modules.

[0083] When F t / F is within the above range (i.e., 1≤F) t When / F≤4), it is beneficial to reduce the overall size of the AR optical module. Specifically, this design can effectively compress the total optical length of the AR optical module, thereby reducing its size.

[0084] In this embodiment, through a reasonable light folding design, the space required in the AR optical module can be reasonably reduced without sacrificing image quality, making it more compact and lightweight.

[0085] Since AR display devices typically require a lightweight and compact design, especially in head-mounted devices, the reduction in the size of AR optical modules is a significant advantage.

[0086] When F t The value of / F is within the range mentioned above (i.e., 1≤F). t ( / F≤4) Even after multiple refractions and reflections by the second prism 4, the virtual imaging light emitted from screen 5 still maintains high imaging quality. This is thanks to the specially designed freeform prism combination and optical film material, which can control the path and polarization state of the light, thereby reducing distortion and chromatic aberration.

[0087] The AR optical module of this application adopts an optical path folding design, which makes full use of the optical element surface of the prism. By folding the virtual imaging ray 6 twice within the second prism 4, not only is excellent optical performance ensured, but the utilization rate of light energy is also significantly improved.

[0088] Specifically, when the virtual imaging light 6 emitted by the screen 5 is folded twice within the second prism 4 and passes through the second prism 4 a total of three times, the ratio between the folded thickness of the virtual imaging light 6 passing through the second prism 4 three times and the total focal length F of the AR optical module is optimized, that is, 1 ≤ F is ensured. t / F≤4. This ratio range allows more light to travel along a predetermined path to the user's eyes. Therefore, light utilization is significantly improved, thereby enhancing the brightness and clarity of the display.

[0089] In summary, through reasonable optical path folding design and optimized F... t With its F-value, the AR optical module of this application embodiment achieves more efficient light path propagation, bringing users a brighter and clearer visual experience.

[0090] When F t The value of / F is within the range mentioned above (i.e., 1 ≤ F). t / F≤4) helps control the propagation path of the virtual imaging ray 6, ensuring that the propagation direction of the virtual imaging ray 6 within the second prism 4 meets design requirements and avoids light scattering or distortion. This helps improve the modulation transfer function (MTF) value of the AR optical module, ensuring image resolution and sharpness.

[0091] Furthermore, by reducing the number of optical elements and simplifying the optical path design, the aforementioned ratio range (i.e., 1 ≤ F) can be achieved. t / F≤4) also helps reduce the manufacturing cost of AR optical modules. Fewer components mean lower material and assembly costs, while also reducing errors and complexity in the manufacturing process.

[0092] When Ft The value of / F is not within the range mentioned above, such as F t / F<1, or F t When / F > 4, it leads to two problems: a larger module size and a decrease in module imaging quality and optical path efficiency. Specifically:

[0093] If F t A value of / F less than 1 means that the optical path length of the virtual imaging ray 6 within the second prism 4 will be too long. This will increase the size of the AR optical module, making the AR display device bulky and affecting the user experience. Especially in head-mounted devices, excessive size may lead to discomfort when worn.

[0094] If F t A / F value greater than 4 means that the propagation path of the virtual imaging ray 6 within the second prism 4 is too short, increasing the risk of light distortion. This will reduce the MTF value of the AR optical module and affect the clarity and resolution of the image.

[0095] In addition, if F t If the / F value is not within a reasonable range, more optical components or a more complex optical path design are required, which increases the difficulty and cost of manufacturing. At the same time, a complex optical path design may also increase errors in the assembly process, affecting the product yield.

[0096] In general, when F t The value of / F satisfies: 1≤F t The requirement of / F≤4 plays a crucial role in the AR optical module design provided in this application embodiment, effectively compressing the size of the AR optical module while ensuring optimized optical performance. Through this design, the AR optical module can achieve a lightweight and compact structure while maintaining high performance, meeting users' high requirements for AR display devices.

[0097] The AR optical module provided in this application embodiment achieves efficient superposition of virtual and real images through the combination of freeform prisms and polarization optical components, and brings the following significant beneficial effects:

[0098] Compact structure: The freeform prism design effectively reduces the size of the AR optical module, making it more portable and easier to integrate;

[0099] High-efficiency optical path: By combining optical prism components with polarization reflection elements, phase delayers and beam splitters, the utilization rate of light and display brightness are significantly improved, ensuring efficient optical path transmission;

[0100] Large field of view: The design of the freeform prism not only optimizes the light transmission path, but also expands the field of view of the AR optical module, providing users with a wider visual experience.

[0101] High imaging quality: At wavelengths of 450nm, 550nm and 610nm, the modulation transfer function (MTF) value of this AR optical module is greater than 0.6 at a spatial frequency of 15lp / mm, ensuring high-definition display effect and enhancing the user's visual experience.

[0102] In summary, the AR optical module of this application embodiment achieves multiple advantages such as compact structure, efficient optical path, large field of view and high imaging quality, bringing users an excellent visual experience.

[0103] See some examples in this application. Figure 1 An aperture stop 2 is provided along the optical axis 1 on the side of the first prism 3 facing away from the second prism 4; the surfaces of the first prism 3 near the aperture stop 2, the second prism 4 away from the aperture stop 2, and the second prism 4 near the screen 5 are all freeform surfaces, and the radius of curvature R of each freeform surface is... i The ratio of the total focal length F of the AR optical module to the total focal length F of the AR optical module satisfies: -10mm ≤ R i / F≤5mm.

[0104] In the example provided in this application, an AR optical module with a specific freeform prism structure is designed.

[0105] See Figure 1 The side of the first prism 3 facing away from the second prism 4 is the aperture stop 2.

[0106] Furthermore, the surfaces of the first prism 3 near the aperture 2, the second prism 4 away from the aperture 2, and the second prism 4 near the screen 5 are designed as freeform surfaces. And these three freeform surfaces R... i (For example, defined as R1, R2, R3 respectively) have a specific ratio relationship with the total focal length F of the entire AR optical module, that is, the ratio between their respective radii of curvature and the total focal length F of the AR optical module satisfies: -10mm≤R i / F≤5mm.

[0107] In the above description, the surfaces of the first prism 3 near the aperture 2, the second prism 4 away from the aperture 2, and the second prism 4 near the screen 5 are designed as freeform surfaces to achieve efficient light folding and transmission, compression of the overall module volume, and improvement of display performance. Other surfaces can be designed as planes or spheres for manufacturing feasibility and cost control considerations. This design choice in this application reflects a balance and optimization between performance, size, manufacturing difficulty, and cost.

[0108] In this example of the application, some surfaces of the first prism 3 and the second prism 4 are designed as freeform surfaces, and the radius of curvature R of these freeform surfaces is... i The ratio between the total focal length F of the AR optical module and the total focal length R is in the range of -10mm ≤ R. i / F≤5mm. This design has significant advantages in the entire AR optical module, and the following is an analysis of this ratio range.

[0109] When R i The value of / F is within the above range (-10mm ≤ R). i When / F≤5mm), that is, when all three freeform surfaces meet this parameter design, the optical path design of the AR optical module can be optimized, while reducing the overall size of the AR optical module. Specifically, the design of freeform surfaces can flexibly control the propagation path of light, allowing virtual imaging light to undergo multiple refractions and reflections within a limited space.

[0110] By reasonably setting the ratio of the radius of curvature of the freeform surface to the total focal length F of the AR optical module, the range of -10mm ≤ R is satisfied. i With an aperture size of ≤5mm, the size of the AR optical module can be effectively reduced, making it more compact and lightweight. This is especially important for head-mounted AR devices, as the reduction in size and weight can significantly improve user comfort.

[0111] When R i The value of / F is within the above range (-10mm ≤ R). i When / F≤5mm), that is, when all three freeform surfaces meet this design requirement, it also helps to improve the optical performance of the AR optical module and reduce aberrations. Specifically, the design of freeform surfaces can better correct aberrations (such as spherical aberration) in the module, thereby improving image quality. This is achieved by controlling the radius of curvature R of the freeform surfaces. i The ratio of the total focal length F of the AR optical module to the total focal length R must satisfy -10mm ≤ R. i With an aperture of F≤5mm, it is possible to ensure that the light maintains high image quality during propagation, reduce distortion and blur, and improve the user's visual experience.

[0112] When Ri The value of / F is within the above range (-10mm ≤ R). i When the radius of curvature of the freeform surface is -10mm ≤ F ≤ 5mm, meaning all three freeform surfaces satisfy this design, the ability to control light is enhanced. Specifically, the freeform surface design allows the AR optical module to more precisely control the direction of light propagation, especially since the superposition of virtual and real images in the AR optical module requires precise optical path control. By reasonably controlling the ratio of the radius of curvature of the freeform surface to the total focal length F of the AR optical module, the range of -10mm ≤ R ≤ 5mm is achieved. i / F≤5mm ensures that the propagation path of light within the prism meets design requirements, avoiding light scattering and energy loss.

[0113] Furthermore, when R i The value of / F is not within the range mentioned above (i.e., R). i / F < -10mm, or R i When / F>5mm), that is, when the three freeform surfaces do not meet the design requirements, the following problems will arise:

[0114] (1) The overall size of the module is too large:

[0115] If R i A small absolute value for / F indicates an excessively large radius of curvature and a too-smooth curvature of the freeform surface. This prevents the optical path from folding effectively, increasing its length and consequently the size of the AR optical module. This makes AR display devices bulky and negatively impacts the user experience.

[0116] (2) Degradation of the module's optical performance:

[0117] If R i An excessively large absolute value of / F indicates that the radius of curvature of the freeform surface is too small, and the curvature of the freeform surface is too steep. This leads to an overly complex light propagation path, increasing the risk of aberrations and distortions, and reducing the imaging quality of the module. Especially in AR optical modules, the superposition of virtual and real images requires high-precision optical design, and excessive curvature can cause image distortion or blurring.

[0118] (3) The module's ability to control light has decreased:

[0119] If R i When the / F value is outside a reasonable range, the propagation path of light cannot be effectively controlled, leading to increased light scattering and energy loss. This reduces display brightness and contrast, negatively impacting the user's visual experience.

[0120] Furthermore, if R iIf the value of / F is not within a reasonable range, the design of the freeform surface will be overly complex, increasing the difficulty and cost of manufacturing. In particular, when the radius of curvature is too small or too large, the manufacturing process may face higher precision requirements, increasing errors and defect rates in production.

[0121] Through this design in the example of this application, the AR optical module can achieve a lightweight and compact structure while maintaining high performance, meeting users' high requirements for AR display devices.

[0122] In some examples of this application, the ratio of the effective focal length F2 of the second prism 4 to the total focal length F of the AR optical module satisfies: 0.1≤F2 / F≤7.

[0123] This example of the application proposes a specific range for the ratio between the effective focal length F2 of the second prism 4 and the total focal length F of the entire AR optical module, namely 0.1 ≤ F2 / F ≤ 7. This choice of optical design parameter is based on optimization considerations for the imaging quality of the AR module. Specifically:

[0124] The ratio of the effective focal length F2 of the second prism 4 to the total focal length F of the AR optical module directly affects the focusing ability of light and the sharpness of the image. When F2 / F is in the range of 0.1 to 7, it can be ensured that the light can be accurately focused at the expected position after passing through the second prism 4, thereby reducing aberrations (such as spherical aberration, coma, etc.) and improving the sharpness and contrast of the image. By reasonably setting the range of the F2 / F ratio, the optical path design inside the AR module can also be optimized, making the propagation of light inside the module more efficient and accurate, thereby further improving the image quality.

[0125] In addition, a well-designed focal length ratio helps to reduce the overall size of the AR module while maintaining image quality. This is because by optimizing the focal length ratio, unnecessary lens elements can be reduced or their size adjusted, thereby miniaturizing the entire module.

[0126] See some examples in this application. Figure 1 The surface of the first prism 3 near the aperture 2 and the surface of the second prism 4 away from the aperture 2 are both free-form surfaces concave towards the aperture 2.

[0127] When the surface of the first prism 3 is concave (or bent) towards the aperture 2, the first prism 3 can more effectively receive the virtual imaging light 6 from a light source such as the screen 5 and guide the virtual imaging light 6 to the aperture 2 through refraction. This design helps to reduce light loss because the incident angle of the virtual imaging light 6 on the surface (freeform surface) of the first prism 3 can be better controlled, thereby reducing reflection and scattering.

[0128] The design that the surface of the first prism 3 near the aperture 2 and the surface of the second prism 4 away from the aperture 2 are both concave (or curved) towards the aperture 2 optimizes the light propagation path, thereby reducing stray light interference and improving image clarity. Simultaneously, it also helps reduce aberrations and distortion, thus enhancing the display quality of the AR optical module.

[0129] See some examples in this application. Figure 1 The bonding interface between the first prism 3 and the second prism 4 has the same surface shape. The surface of the second prism 4 away from the aperture 2 has the same surface shape as the surface of the first prism 3 near the aperture 2. The optical prism assembly formed by bonding the first prism 3 and the second prism 4 has zero transmittance.

[0130] By bonding the first prism 3 and the second prism 4 together, the number of individual components in the AR optical module can be reduced, simplifying the overall structure. This design not only reduces assembly complexity but also reduces air gaps between optical components, thereby reducing light reflection and scattering and improving the overall optical efficiency of the AR optical module.

[0131] The interface surface profile between the first prism 3 and the second prism 4 is identical, and the surface profile of the second prism 4 away from the aperture 2 is identical to the surface profile of the first prism 3 near the aperture 2. This consistent surface profile design helps reduce light distortion and aberrations, improving image quality. In particular, in AR optical modules, the superposition of virtual and real images requires high-precision optical design, and the cemented lens assembly design can effectively improve the performance of the optical system.

[0132] In this example of the application, the transmitted optical power of the cemented lens assembly is zero. This design means that the cemented lens assembly does not introduce additional optical power, thus not affecting the focal length design of the entire AR optical module. This design allows for more precise focal length control of the AR optical module, ensuring accurate superposition of virtual and real images and enhancing the user's visual experience.

[0133] Zero optical power means that the cemented lens assembly has no converging or diverging effect on light; that is, the direction of light propagation remains unchanged after passing through the cemented lens assembly. This characteristic is crucial for AR optical modules because it ensures visual consistency between virtual images and the real world, and users will not perceive image distortion or displacement caused by optical elements. Furthermore, the zero optical power design simplifies the design of AR optical modules because it eliminates the need for additional lenses or prisms to compensate for aberrations that the cemented lens assembly may introduce, thereby reducing the complexity and cost of AR optical modules.

[0134] See some examples in this application. Figure 1 The AR optical module further includes a first polarizing element 7, which is disposed on the surface of the first prism 3 near the aperture 2, and the transmission axis of the first polarizing element 7 is parallel to the transmission axis of the polarizing reflection element 8.

[0135] The first polarizing element 7 is, for example, a polarizing film. Specifically, a polarizing film (such as a polarizer) is an optical element that can selectively transmit light polarized in a specific direction.

[0136] In this application, the first polarizing element 7 is used to control the polarization state of light.

[0137] In this application, by setting the first polarizing element 7 parallel to the transmission axis of the polarizing reflective element 8, stray light can be filtered out, thereby improving the contrast of the virtual image. This is very important for AR optical modules because virtual images need to be superimposed on the light in the real environment, and high contrast ensures the clarity of the virtual image.

[0138] See some examples in this application. Figure 1 The polarization reflection element 8 and the first phase delayer 9 are stacked at the bonding interface between the first prism 3 and the second prism 4, and the beam splitter 10 is disposed on the surface of the second prism 4 away from the aperture 2.

[0139] The polarization reflecting element 8 and the first phase retarder 9 are stacked at the cemented interface between the first prism 3 and the second prism 4. This design effectively controls the polarization state and propagation direction of light. The first phase retarder 9 is, for example, a quarter-wave plate. The combination of the polarization reflecting element 8 and the first phase retarder 9 enables selective reflection and transmission of light, thereby improving light utilization.

[0140] The beam splitter 10 is disposed on the surface of the second prism 4 away from the aperture 2. The beam splitter 10 is a semi-transparent and semi-reflective film, which can further divide the light into two parts: transmission and reflection, to ensure the separation of the light paths of the virtual image and the real image, and improve the overall efficiency of the AR optical module.

[0141] The combination of the polarization reflection element 8 and the first phase delayer 9 effectively filters out unwanted polarized light, ensuring that the light from the virtual image can pass clearly through the AR optical module. The beam splitter 10 further enhances the light separation effect, reduces stray light interference, and thus improves the clarity of the virtual image.

[0142] The stacked design of the polarization reflective element 8 and the first phase retarder 9 effectively reduces light reflection and scattering, thus minimizing light energy loss. The arrangement of the beam-splitting element 10 optimizes the light propagation path. This design enhances the user's visual experience.

[0143] In this example design, the polarization reflective element 8 and the first phase retarder 9 are stacked on the adhesive interface, and the beam splitter 10 is disposed on the surface of the second prism 4. This design reduces the number of individual components in the AR optical module and simplifies the overall structure. This not only reduces assembly complexity but also reduces air gaps between AR optical modules, thereby reducing light reflection and scattering and improving the overall efficiency of the AR optical module. Simultaneously, this design also reduces manufacturing costs and improves production efficiency and product yield.

[0144] By rationally configuring the positions and functions of the polarization reflection element 8, the first phase delayer 9, and the beam splitter 10, the polarization state and optical path propagation of the AR optical module can be ensured to be more stable. This design can reduce performance fluctuations caused by changes in polarization state or optical path offset during the use of the AR optical module, thereby improving the long-term stability and reliability of the AR optical module.

[0145] See some examples in this application. Figure 1 The AR optical module further includes a second phase delay unit 11 and a second polarizing element 12, which are stacked on the surface of the second prism 4 away from the aperture 2.

[0146] The second phase delayer 11 is, for example, a quarter-wave plate.

[0147] The second polarizing element 12 is, for example, a polarizing film. A polarizing film (such as a polarizer) is an optical element that can selectively transmit light polarized in a specific direction.

[0148] In this example of the application, a second phase delayer 11 and a second polarizing element 12 are introduced, both of which are optical films specifically located on the surface of the second prism 4 away from the aperture 2. The combination of the second phase delayer 11 and the second polarizing element 12 can further control the polarization state of the light. Specifically, the second phase delayer 11 can adjust the phase delay of the light, while the second polarizing element 12 can selectively transmit light with a specific polarization direction. This design ensures that the light maintains the required polarization state during propagation, thereby optimizing the polarization management of the AR optical module, reducing polarization interference, and improving optical performance.

[0149] The combination of the second phase delayer 11 and the second polarizing element 12 effectively filters out unwanted polarized and stray light, ensuring that the light from the virtual image can pass clearly through the AR optical module. This design not only significantly improves the clarity of the virtual image but also prevents screen image leakage.

[0150] The stacked design of the second phase delayer 11 and the second polarizing element 12 effectively reduces light reflection and scattering, thus minimizing light energy loss. This design ensures that more light is effectively utilized, improving the overall efficiency of the AR optical module, thereby enhancing display brightness and image quality, and improving the user's visual experience.

[0151] In this application, by stacking the second phase retarder 11 and the second polarizing element 12 on the surface of the second prism 4 away from the aperture 2, the number of independent components in the AR optical module can be reduced, simplifying the overall structure. This design not only reduces assembly complexity but also reduces air gaps between optical components, thereby reducing light reflection and scattering and improving the overall efficiency of the optical system.

[0152] The combination of the second phase delayer 11 and the second polarizing element 12 ensures a more stable polarization state and optical path propagation of the AR optical module. This design reduces performance fluctuations caused by changes in polarization state or optical path offset during use, improving the long-term stability and reliability of the AR optical module.

[0153] It should be noted that, in this application, the combination of the first polarizing element 7, the second phase delayer 11, and the second polarizing element 12 can be used to filter stray light.

[0154] See some examples in this application. Figure 1 A third polarizing element 13 and a third phase delayer 14 are stacked sequentially on the light-emitting surface of the screen 5. The third polarizing element 13 is perpendicular to the transmission axis of the polarizing reflection element 8. The virtual imaging light 6 emitted by the screen 5 passes through the third polarizing element 13 and the third phase delayer 14 in sequence and becomes circularly polarized light.

[0155] Through the combination of the third polarizing element 13 and the third phase delayer 14, the virtual imaging light 6 emitted by the screen 5 is converted into circularly polarized light. Circularly polarized light has a uniform polarization state, enabling better control of the light propagation direction within the AR optical module and reducing polarization interference. This design ensures that the light maintains the required polarization state during propagation, thereby improving the light control accuracy of the AR optical module and reducing aberrations and light energy loss.

[0156] Circularly polarized light effectively reduces interference from stray and unwanted polarized light, ensuring that the light from virtual images can pass clearly through the AR optical module. This design significantly improves the clarity of virtual images, especially in AR optical modules where virtual images need to be superimposed on the light in the real environment; high clarity ensures the visibility and realism of the virtual images.

[0157] Through the combination of the third polarizing element 13 and the third phase delayer 14, the virtual imaging light 6 emitted by the screen 5 is converted into circularly polarized light. This design effectively reduces light reflection and scattering, thus minimizing light energy loss. Circularly polarized light has higher propagation efficiency in the AR optical module, ensuring that more light is effectively utilized, improving the overall efficiency of the AR optical module, thereby enhancing display brightness and image quality, and improving the user's visual experience.

[0158] By directly stacking the third polarizing element 13 and the third phase delayer 14 on the light-emitting surface of the screen 5, the number of independent components in the AR optical module can be reduced, simplifying the overall structure.

[0159] The circularly polarized light design ensures a more stable polarization state for the AR optical module, reducing performance fluctuations caused by polarization changes during use. This design improves the long-term stability and reliability of the AR optical module, ensuring the device maintains high performance during operation.

[0160] Of course, if the screen 5 can directly emit circularly polarized light, the aforementioned third polarizing element 13 and third phase delayer 14 can be omitted.

[0161] According to the AR optical module provided in the embodiments of this application, its modulation transfer function (MTF) values ​​at wavelengths of 450nm, 550nm and 610nm are all greater than 0.6 at a spatial frequency of 15lp / mm.

[0162] The modulation transfer function (MTF) is an important indicator of the imaging quality of an optical system, reflecting its ability to resolve details at different spatial frequencies. A higher MTF value indicates that the optical system can resolve details more clearly.

[0163] In this example of the application, the MTF values ​​of the AR optical module at wavelengths of 450nm, 550nm and 610nm are all greater than 0.6 at a spatial frequency of 15lp / mm, indicating that the AR optical module has extremely high resolution and can clearly display the details of virtual and real images, ensuring that users obtain a high-quality visual experience.

[0164] The AR optical module of this application exhibits MTF values ​​greater than 0.6 at three typical wavelengths: 450nm (blue light), 550nm (green light), and 610nm (red light), demonstrating excellent optical performance across a wide wavelength range. This design ensures that the AR optical module maintains high resolution and clear imaging under various lighting conditions (such as different colored light sources or ambient light), enhancing the user's visual experience.

[0165] A high MTF value indicates that the AR optical module has effectively controlled chromatic aberration and aberrations (such as spherical aberration) during the design and manufacturing process. By optimizing the design of optical components and the selection of materials, the AR optical module can maintain a high MTF value at different wavelengths, reducing image distortion and blurring, and ensuring that the superposition of virtual and real images is clearer and more accurate.

[0166] A high MTF value not only reflects the imaging quality of the AR optical module, but also indicates that the AR optical module has high stability and reliability in its design.

[0167] In this example of the application, the modulation transfer function (MTF) values ​​of the AR optical module at wavelengths of 450nm, 550nm, and 610nm are all greater than 0.6 at a spatial frequency of 15lp / mm. This design plays a crucial role in the AR optical module, ensuring not only high-resolution imaging and excellent optical performance over a wide wavelength range, but also reducing chromatic aberration and aberrations, enhancing the user experience, and improving the stability and reliability of the optical system. Through this design, the AR optical module can achieve a lightweight and compact structure while maintaining high performance, meeting users' high requirements for AR display devices.

[0168] The AR optical module provided in this application embodiment can achieve good imaging quality while miniaturizing its size, and can also achieve a field of view of 50° or even larger.

[0169] According to another embodiment of this application, an AR display device is provided, the AR display device including a housing and an AR optical module as described above.

[0170] The AR display device is, for example, a smart head-mounted device, such as AR smart glasses or AR smart helmet.

[0171] According to another embodiment of this application, an imaging display method for an AR optical module is provided, wherein the virtual imaging display method specifically includes the following steps 100 to 400:

[0172] Step 100: Display a virtual image on screen 5, wherein the virtual imaging light 6 emitted by screen 5 is circularly polarized light;

[0173] Step 200: Guide the virtual imaging ray 6 to the second prism 4 on the side away from the aperture 2. After the virtual imaging ray 6 enters the second prism 4, it is reflected by the first phase delay 9 and the polarization reflection element 8 set on the side of the second prism 4 near the aperture 2.

[0174] Step 300: The reflected virtual imaging light ray 6 is further guided to the beam splitter 10 on the side of the second prism 4 away from the aperture 2. The beam splitter 10 reflects the virtual imaging light ray 6 again and makes it pass through the second prism 4 and enter the first prism 3.

[0175] Step 400: The virtual imaging light 6 passing through the second prism 4 is guided to the first prism 3, and enters the aperture 2 through the first polarizing element 7 set on the side of the first prism 3 near the aperture 2, and finally realizes the image display.

[0176] The virtual imaging ray 6 passes through the second prism 4 a total of three times, and its folding thickness F t The total focal length F of the AR optical module satisfies the following relationship: 1 ≤ F t / F≤4.

[0177] According to step 100 above: the virtual image is displayed through the screen 5, and the virtual imaging light 6 emitted by the screen 5 can be directly circularly polarized light or processed to become circularly polarized light. That is, this step 100 mainly generates and emits circularly polarized light containing virtual image information as the basic light source for imaging display.

[0178] Optionally, when the virtual imaging light 6 emitted by the screen 5 is non-circularly polarized light, before the virtual imaging light 6 enters the second prism 4, the virtual imaging light 6 is made to pass through the third polarizing element 13 and the third phase delayer 14 in sequence, thereby converting the non-circularly polarized light into circularly polarized light.

[0179] According to step 200 above: the virtual imaging light ray 6 emitted from the screen 5 is guided to the second prism 4. After entering the second prism 4, the virtual imaging light ray 6 is reflected by the first phase delay unit 9 and the polarization reflection element 8, which are located on the side of the second prism 4 near the aperture 2. This step 200 guides the light ray through the second prism 4 and uses the first phase delay unit 9 and the polarization reflection element 8 to reflect and adjust the phase of the light ray, preparing for the subsequent light path and imaging effect.

[0180] According to step 300 above: the reflected virtual imaging light 6 is guided to the beam splitter 10 on the side of the second prism 4 away from the aperture 2. The beam splitter 10 reflects the light again, allowing it to pass through the second prism 4 and enter the first prism 3. The function of this step 300 is to reflect the reflected light again through the beam splitter 10, see [link to previous steps]. Figure 1 This changes the direction of light propagation, allowing it to pass through the second prism 4 and enter the first prism 3, further adjusting the path of the light.

[0181] According to step 400 above: the virtual imaging light 6 passing through the second prism 4 is guided to the first prism 3, and enters the aperture 2 through the first polarizing element 7 located on the side of the first prism 3 near the aperture 2, thus achieving image display. The function of this step is: the virtual imaging light 6 passes through the second prism 4 and enters the first prism 3, then undergoes polarization processing by the first polarizing element 7, and finally enters the aperture 2, completing the image display of the virtual image.

[0182] The virtual imaging ray 6 is folded twice within the second prism 4, and passes through the second prism 4 a total of three times, with a folding thickness F. t The total focal length F of the AR optical module satisfies the following relationship: 1 ≤ F t / F≤4. By controlling the number of folds and transmissions of the virtual imaging ray 6 within the second prism 4, and adjusting the focal length ratio (F... t / F) is used to optimize the imaging effect and performance of the AR optical module, ensuring that the virtual image can be displayed clearly and accurately in the user's field of vision.

[0183] The AR optical module of this application will be described in detail below through Examples 1 to 3.

[0184] Example 1

[0185] See Figure 2 The AR optical module provided in this embodiment 1 includes the following optical elements:

[0186] An optical prism assembly includes a first prism 3 and a second prism 4 bonded together along the same optical axis 1, wherein both the first prism 3 and the second prism 4 are freeform prisms; an aperture 2 is provided on the side of the first prism 3 facing away from the second prism 4; wherein the surface of the first prism 3 near the aperture 2, the surface of the second prism 4 away from the aperture 2, and the surface of the second prism 4 near the screen 5 are freeform surfaces, and the surface of the first prism 3 near the aperture 2 and the surface of the second prism 4 away from the aperture 2 are both concave towards the aperture 2;

[0187] The AR optical module further includes a polarization reflection element 8, a first phase retarder 9, and a beam splitter 10; wherein: the polarization reflection element 8 and the first phase retarder 9 are stacked on the bonding interface between the first prism 3 and the second prism 4, and the beam splitter 10 is disposed on the surface of the second prism 4 away from the aperture 2.

[0188] The AR optical module also includes a screen 5, which is located on one side of the second prism 4, and the central axis of the screen 5 is perpendicular to the optical axis 1; the virtual imaging light 6 emitted by the screen 5 is folded twice within the second prism 4, and passes through the second prism 4 a total of three times, and the virtual imaging light 6 passes through the second prism 4 through a folding thickness F three times. t The ratio of the total focal length F of the entire AR optical module is 2.6;

[0189] Wherein, the bonding interface surface type F of the first prism 3 and the second prism 4 is the same, and the surface of the second prism 4 away from the aperture 2 is the same as the surface of the first prism 3 near the aperture 2. The transmitted light power of the bonding lens group is zero.

[0190] The AR optical module further includes a first polarizing element 7, which is disposed on the surface of the first prism 3 near the aperture 2, and the transmission axis of the first polarizing element 7 is parallel to the transmission axis of the polarizing reflection element 8.

[0191] The AR optical module also includes a second phase delayer 11 and a second polarizing element 12, which are stacked on the surface of the second prism 4 away from the aperture 2.

[0192] A third polarizing element 13 and a third phase delayer 14 are stacked sequentially on the light-emitting surface of the screen 5. The third polarizing element 13 is perpendicular to the transmission axis of the polarizing reflective element 8. The light 6 emitted by the screen 5 passes through the third polarizing element 13 and the third phase delayer 14 sequentially and becomes circularly polarized light.

[0193] Please refer to Table 1 below for the optical parameters of the AR optical module provided in this embodiment 1.

[0194] Table 1

[0195]

[0196]

[0197] Figures 3a-3cThe modulation transfer function (MTF) curves of the AR optical module provided in Example 1 are shown at 450nm, 550nm, and 610nm, respectively. Figures 3a-3c It can be seen that at a spatial frequency of 15 lp / mm, the MTF value of the AR optical module is higher than 0.8 at a wavelength of 450 nm, at a wavelength of 550 nm, and at a wavelength of 610 nm.

[0198] Figures 4a-4c Distortion curves of the AR optical module provided in Example 1 at 450nm, 550nm, and 610nm are shown below. Figures 4a-4c It can be seen that: at a wavelength of 450nm, the distortion value of the AR optical module is less than 5%; at a wavelength of 550nm, the distortion value of the AR optical module is less than 5%; and at a wavelength of 610nm, the distortion value of the AR optical module is less than 5%.

[0199] Figures 5a-5c The dot plots of the AR optical module provided in Embodiment 1 at 450nm, 550nm, and 610nm are shown below. Figures 5a-5c It can be seen that at a wavelength of 450nm, the RMS radius of the AR optical module is less than 9mm; at a wavelength of 550nm, the RMS radius of the AR optical module is less than 7mm; and at a wavelength of 610nm, the RMS radius of the AR optical module is less than 8mm.

[0200] Example 2

[0201] The optical architecture provided in this embodiment 2 is described in [reference]. Figure 6 Its optical architecture is the same as that of Embodiment 1 above, except that the virtual imaging ray 6 passes through the folded thickness F three times within the second prism 4. t The total focal length F-ratio of the entire AR optical module is 4; and the optical parameters are designed as follows, please refer to Table 2 for details;

[0202] Table 2

[0203]

[0204]

[0205]

[0206] Figures 7a-7c The modulation transfer function (MTF) curves of the AR optical module provided in Example 2 are shown at 450nm, 550nm, and 610nm, respectively. Figures 7a-7cIt can be seen that at a spatial frequency of 15 lp / mm, the MTF value of the AR optical module is higher than 0.6 at a wavelength of 450 nm, at a wavelength of 550 nm, and at a wavelength of 610 nm.

[0207] Figures 8a-8c The distortion curves of the AR optical module provided in Example 2 are shown at 450nm, 550nm, and 610nm, respectively. Figures 8a-8c It can be seen that: at a wavelength of 450nm, the distortion value of the AR optical module is less than 13%; at a wavelength of 550nm, the distortion value of the AR optical module is less than 13%; and at a wavelength of 610nm, the distortion value of the AR optical module is less than 13%.

[0208] Figures 9a-9c Dot plots of the AR optical module provided in Embodiment 2 at 450nm, 550nm, and 610nm respectively, from Figures 9a-9c It can be seen that at a wavelength of 450nm, the RMS radius of the AR optical module is less than 12mm; at a wavelength of 550nm, the RMS radius of the AR optical module is less than 12mm; and at a wavelength of 610nm, the RMS radius of the AR optical module is less than 13mm.

[0209] Example 3

[0210] The optical architecture provided in this embodiment 3 is described in [reference]. Figure 10 Its optical architecture is the same as that of Embodiment 1 above, except that the virtual imaging ray 6 passes through the folded thickness F three times within the second prism 4. t The total focal length F-ratio of the entire AR optical module is 1.0; and the optical parameters are designed as follows, please refer to Table 3 for details;

[0211] Table 3

[0212]

[0213]

[0214] Figures 11a-11c The modulation transfer function (MTF) curves of the AR optical module provided in Example 3 are shown at 450nm, 550nm, and 610nm, respectively. Figures 11a-11c It can be seen that at a spatial frequency of 15 lp / mm, the MTF value of the AR optical module is higher than 0.7 at a wavelength of 450 nm, higher than 0.6 at a wavelength of 550 nm, and higher than 0.7 at a wavelength of 610 nm.

[0215] Figures 12a-12cThe distortion curves of the AR optical module provided in Example 3 at 450nm, 550nm, and 610nm are shown respectively. Figures 12a-12c It can be seen that: at a wavelength of 450nm, the distortion value of the AR optical module is less than 13%; at a wavelength of 550nm, the distortion value of the AR optical module is less than 13%; and at a wavelength of 610nm, the distortion value of the AR optical module is less than 13%.

[0216] Figures 13a-13c Dot plots of the AR optical module provided in this embodiment 3 at 450nm, 550nm, and 610nm, respectively. Figures 13a-13c It can be seen that: at a wavelength of 450nm, the RMS radius value of the AR optical module is less than 11mm; at a wavelength of 550nm, the RMS radius value of the AR optical module is less than 10mm; and at a wavelength of 610nm, the RMS radius value of the AR optical module is less than 10mm.

[0217] The specific implementation methods of the AR display device and AR optical module of this application can refer to the various embodiments of the AR optical module described above. Therefore, they have at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0218] The above embodiments mainly describe 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. For the sake of brevity, they will not be elaborated here.

[0219] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. An AR optical module, characterized in that, include: An optical prism assembly includes a first prism (3) and a second prism (4) bonded together along the same optical axis (1). Both the first prism (3) and the second prism (4) are freeform prisms. The optical prism assembly is used to transmit real ambient light and fold virtual imaging light (6) from a screen (5). The polarization optical component includes a polarization reflection element (8) and a first phase retarder (9) disposed between the first prism (3) and the second prism (4), and a beam splitter (10) disposed on the side of the second prism (4) away from the first prism (3), wherein the first phase retarder (9) is located in the optical path between the beam splitter (10) and the polarization reflection element (8). The screen (5) is located on the light-incident side of the second prism (4), and its central axis is perpendicular to the optical axis (1). The virtual imaging light rays (6) emitted by the screen (5) pass through the following paths in sequence: After entering the second prism (4), it is reflected by the polarization reflection element (8) and the first phase delayer (9) to the beam splitter (10), and after being reflected by the beam splitter (10), it passes through the second prism (4), enters the first prism (3), and finally exits. The virtual imaging ray (6) passes through the second prism (4) a total of three times, and the folding thickness F of the ray passing through the second prism (4) three times is... t The total focal length F of the AR optical module satisfies: 1 ≤ F t / F≤4.

2. The AR optical module according to claim 1, characterized in that, An aperture stop (2) is provided along the optical axis (1) on the side of the first prism (3) facing away from the second prism (4); The surface of the first prism (3) near the aperture (2), the surface of the second prism (4) away from the aperture (2), and the surface of the second prism (4) near the screen (5) are all freeform surfaces, and the radius of curvature R of each freeform surface is... i The ratio of the total focal length F of the AR optical module to the total focal length F of the AR optical module satisfies: -10 ≤ R i / F≤5.

3. The AR optical module according to claim 1 or 2, characterized in that, The ratio of the effective focal length F2 of the second prism (4) to the total focal length F of the AR optical module satisfies: 0.1≤F2 / F≤7.

4. The AR optical module according to claim 2, characterized in that, The surface of the first prism (3) near the aperture (2) and the surface of the second prism (4) away from the aperture (2) are both free-form surfaces concave towards the aperture (2).

5. The AR optical module according to claim 4, characterized in that, The bonding interface between the first prism (3) and the second prism (4) has the same surface shape. The surface of the second prism (4) away from the aperture (2) has the same surface shape as the surface of the first prism (3) near the aperture (2). The optical prism assembly formed by bonding the first prism (3) and the second prism (4) has zero transmittance.

6. The AR optical module according to claim 5, characterized in that, The AR optical module further includes a first polarizing element (7), which is disposed on the surface of the first prism (3) near the aperture (2), and its transmission axis is parallel to the transmission axis of the polarizing reflection element (8).

7. The AR optical module according to claim 5, characterized in that, The polarization reflection element (8) and the first phase delayer (9) are stacked at the bonding interface between the first prism (3) and the second prism (4), and the beam splitter (10) is disposed on the surface of the second prism (4) away from the aperture (2).

8. The AR optical module according to claim 7, characterized in that, The AR optical module further includes a second phase delay (11) and a second polarizing element (12), which are stacked on the surface of the second prism (4) away from the aperture (2).

9. The AR optical module according to claim 1, characterized in that, A third polarizing element (13) and a third phase delayer (14) are stacked sequentially on the light-emitting surface of the screen (5). The third polarizing element (13) is perpendicular to the transmission axis of the polarizing reflective element (8). The virtual imaging light (6) emitted by the screen (5) passes through the third polarizing element (13) and the third phase delayer (14) in sequence, and becomes circularly polarized light.

10. An AR display device, characterized in that, include: shell; and The AR optical module as described in any one of claims 1-9.

11. An imaging and display method for an AR optical module, characterized in that, include: The virtual image is displayed on the screen (5), and the virtual imaging light (6) emitted by the screen (5) is circularly polarized light; The virtual imaging ray (6) is guided to the second prism (4) on the side away from the aperture (2). After the virtual imaging ray (6) enters the second prism (4), it is reflected by the first phase delay (9) and polarization reflection element (8) set on the side of the second prism (4) near the aperture (2). The reflected virtual imaging light (6) is further guided to the beam splitter (10) on the side of the second prism (4) away from the aperture (2), and the beam splitter (10) reflects the virtual imaging light (6) again and makes it pass through the second prism (4) into the first prism (3); The virtual imaging light (6) passing through the second prism (4) is guided to the first prism (3), and enters the aperture (2) through the first polarizing element (7) set on the side of the first prism (3) near the aperture (2), and finally realizes the imaging display; The virtual imaging ray (6) passes through the second prism (4) a total of three times, and its folding thickness F t The total focal length F of the AR optical module satisfies the following relationship: 1 ≤ F t / F≤4.

Images