Ar optical module, imaging display method thereof and ar display device

Abstract

The embodiment of the application provides an AR optical module, an imaging display method thereof and an AR display device; the AR optical module comprises an optical prism assembly, a polarized optical assembly and a screen; the optical prism assembly comprises a first prism and a second prism which are cemented along the same optical axis and are used for transmitting real environment light and folding virtual imaging light; the polarized optical assembly comprises a polarized reflection element and a phase retarder which are arranged between the first prism and the second prism, and a light splitting element which is arranged on one side of the lower surface of the first prism, and the phase retarder is located between the light splitting element and the polarized reflection element; the screen is arranged on one side of the upper surface of the second prism and is opposite to the lower surface of the first prism, and the central axis thereof is perpendicular to the optical axis; the virtual imaging light emitted by the screen is folded twice in the first prism and totally passes through the first prism three times, and the folding thickness F t of the virtual imaging light passing through the first prism three times satisfies 1<=F t / F<=1.6.

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] Augmented Reality (AR) technology provides users with an immersive visual experience by overlaying virtual images onto real-world scenes. As a core component of AR devices, the performance of the AR optical module directly impacts the display quality and user experience. Currently, traditional AR optical modules mainly suffer from the following problems:

[0003] (1) Complex structure: Traditional AR optical modules usually use a combination of multiple lenses, and the optical path design is complex, resulting in a large module size, which makes it difficult to meet the requirements of lightweighting.

[0004] (2) Small field of view (FOV): Due to the limitations of optical design, the field of view of traditional AR modules is small, which limits the user's field of vision and affects the sense of immersion.

[0005] (3) High cost: Traditional AR modules use a large number of optical components and require high processing precision, resulting in high manufacturing costs.

[0006] To address these issues, the industry has been developing new AR optical module designs to simplify structure, expand field of view, and reduce costs. However, no existing technology has yet proposed an AR optical module that can meet the requirements of lightweight design while also achieving a large field of view and cost-effectiveness. Summary of the Invention

[0007] 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.

[0008] In a first aspect, this application provides an AR optical module. The AR optical module includes:

[0009] 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.

[0010] A polarization optical component includes a polarization reflecting element and a phase retarder disposed between a first prism and a second prism, and a beam splitter disposed on one side of the lower surface of the first prism, wherein the phase retarder is located in the optical path between the beam splitter and the polarization reflecting element;

[0011] A screen is disposed on one side of the upper surface of the second prism and opposite to the lower surface of the first prism, and the central axis of the screen is perpendicular to the optical axis;

[0012] The virtual imaging light emitted from the screen is folded twice within the first prism, passing through the first prism a total of three times, and the virtual imaging light passes through the first prism for a total folding thickness F. t The ratio between the total focal length F of the AR optical module and the total focal length F of the AR optical module satisfies: 1 ≤ F t / F≤1.6.

[0013] Optionally, the lower surface of the first prism and the upper surface of the second prism are both freeform surfaces, and the radius of curvature R of each freeform surface is... i The total focal length F of the AR optical module satisfies the following condition: -2≤R i / F≤5.

[0014] Optionally, the AR optical module includes an aperture stop, which is disposed along the optical axis on the side of the first prism away from the second prism;

[0015] The bonding interface of 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 transmittance of the optical prism assembly composed of the first prism and the second prism is zero.

[0016] 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 the transmission axis of the first polarizing element is perpendicular to the transmission axis of the polarizing reflection element.

[0017] Optionally, the polarization reflection element and the phase retarder are stacked and form a composite element, which is disposed at the bonding interface between the first prism and the second prism;

[0018] The beam splitter is disposed on the lower surface of the first prism.

[0019] Optionally, the effective focal length F1 of the first prism and the total focal length F of the AR optical module satisfy: 1≤F1 / F≤1.5.

[0020] Optionally, a second polarizing element is disposed on the light-emitting surface of the screen, the second polarizing element being configured to convert the virtual imaging light emitted by the screen into linearly polarized light.

[0021] Optionally, the virtual imaging light emitted from the screen is converted into linearly polarized light and then enters the second prism. The linearly polarized light is converted into circularly polarized light after passing through the polarization reflection element and the phase retarder. The circularly polarized light is incident on the beam splitter on one side of the lower surface of the first prism and is reflected. The reflected circularly polarized light is converted into linearly polarized light again after passing through the phase retarder, and after being reflected by the polarization reflection element, it finally exits through the first prism. In this process, the virtual imaging light is folded twice inside the first prism and passes through the first prism a total of three times.

[0022] Secondly, this application provides an AR display device, the AR display device comprising:

[0023] The outer casing; and

[0024] The AR optical module as described in the first aspect.

[0025] Thirdly, this application provides an imaging display method for an AR optical module, the imaging display method comprising:

[0026] The virtual imaging light emitted from the screen passes through the second polarizing element and becomes linearly polarized light;

[0027] After the linearly polarized light enters the second prism, it becomes circularly polarized light after passing through the polarization reflection element and the phase retarder.

[0028] The circularly polarized light is incident on the beam-splitting element on the lower surface of the first prism and is reflected;

[0029] The circularly polarized light, after being reflected, passes through the phase delayer again to become linearly polarized light. This linearly polarized light is then reflected by the polarization reflection element and finally exits through the first prism.

[0030] The virtual imaging light emitted from the screen is folded twice within the first prism, passing through the first prism a total of three times, and the virtual imaging light passes through the first prism for a total folding thickness F. t The ratio between the total focal length F of the AR optical module and the total focal length F of the AR optical module satisfies: 1 ≤ F t / F≤1.6.

[0031] The beneficial effects of this application are as follows:

[0032] This application provides an AR optical module that simplifies the optical structure through the design of two freeform prisms (first prism 3 and second prism 4) bonded together. This design significantly reduces the module's size, promotes the compact development of optical modules, and fully utilizes the advantages of freeform surfaces to significantly expand the field of view (FOV), providing users with a more immersive visual experience.

[0033] The application of freeform prisms optimizes the light propagation path and improves light energy utilization, enabling virtual images to be transmitted to the human eye more efficiently. Simultaneously, through the synergistic effect of polarization reflection elements, phase delayers, and beam splitters, this application achieves efficient energy transfer and utilization in the virtual optical path, significantly improving energy utilization and imaging performance.

[0034] In terms of optical performance, the AR optical module of this application exhibits excellent performance. The modulation transfer function (MTF) values ​​of the module at wavelengths of 450nm, 550nm and 610nm are all greater than 0.8 at a spatial frequency of 15lp / mm. This performance fully guarantees the clarity of the image.

[0035] Furthermore, the virtual imaging light folds twice within the first prism and passes through a total of three times. This design not only optimizes the optical path but also improves the imaging performance of the module by controlling the ratio between the folding thickness Ft of the virtual imaging light passing through the first prism three times and the total focal length F of the AR optical module.

[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 6 The 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. Light ray; 7. First polarizing element; 8. Polarizing reflection element; 9. Phase delayer; 10. Beam splitter; 11. Second polarizing element. 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 rays 6 from the screen 5. The polarizing optical assembly includes a polarizing reflective element 8 and a phase retarder 9 disposed between the first prism 3 and the second prism 4, and a beam splitter 10 disposed on one side of the lower surface of the first prism 3. The phase retarder 9 is located in the optical path between the beam splitter 10 and the polarizing reflective element 8. The screen 5 is disposed on one side of the upper surface of the second prism 4, opposite the lower surface of the first prism 3, and the central axis of the screen 5 is perpendicular to the optical axis 1. The virtual imaging light rays 6 emitted from the screen 5 are folded twice within the first prism 3, passing through the first prism 3 a total of three times. The virtual imaging light rays 6 pass through the first prism 3 three times with a folding thickness F. t The ratio between the total focal length F of the AR optical module and the total focal length F of the AR optical module satisfies: 1 ≤ F t / F≤1.6.

[0060] The AR optical module provided in this application embodiment is a design based on two freeform prisms bonded together and combined with polarizing optical components, aiming to achieve efficient superposition of virtual and real images. Specifically, the AR optical module provided in this application embodiment, through the synergistic effect of the first prism 3 and the second prism 4 with various optical films, can not only efficiently transmit ambient light, but also perform multiple refractions and reflections on the virtual imaging light 6 from the screen 5, thereby projecting the virtual imaging light 6 into the user's eyes. Through the above series of optical designs, this AR optical module achieves the fusion of virtual information and the real environment, providing users with an immersive AR visual experience. This design not only improves the image display effect, but also significantly reduces the size and weight of the module by optimizing the optical path structure, making it have broad application potential in augmented reality devices.

[0061] The AR optical module provided in this application includes an optical prism assembly. Specifically, see... Figure 1 The optical prism assembly mainly consists of a first prism 3 and a second prism 4 bonded together along the same optical axis 1, forming a single integral component. Both the first prism 3 and the second prism 4 are freeform surface prisms. This embodiment reduces the number of independent optical elements in the module through the bonding design of the optical prism assembly, lowering the assembly complexity of the entire module and facilitating a reduction in the overall module size. The design of the optical prism assembly not only facilitates the folding of the virtual imaging light ray 6 but also efficiently transmits ambient light, ensuring good superposition and fusion of virtual and real images, thus providing users with a more realistic AR visual experience.

[0062] To further optimize the size of the AR optical module, the screen 5 is positioned perpendicular to the optical axis 1. This design avoids the AR optical module being too long along the optical axis 1, thus effectively reducing the overall size of the module. By aligning the screen 5 perpendicular to the optical axis 1, not only is the optical path design simplified, but the AR optical module becomes more compact, facilitating integration into AR devices, while ensuring optical path propagation efficiency and imaging quality.

[0063] In the design of the AR optical module provided in this application embodiment, various optical films are also incorporated, including a polarization reflection element 8, a phase delayer 9, and a beam splitter 10. These optical films play an important role together, working in conjunction with the optical prism assembly (first prism 3 and second prism 4) to achieve the double folding of the virtual imaging light ray 6 emitted from the screen 5. The specific double folding process of the virtual imaging light ray 6 in this application is as follows:

[0064] See Figure 1The virtual imaging light 6 emitted from the screen 5 (becoming linearly polarized light) enters the second prism 4. This virtual imaging light 6 (i.e., linearly polarized light) then passes through the polarization reflection film 8 and phase retarder 9 on the side of the second prism 4 near the aperture 2, converting into circularly polarized light, and then incident on the lower surface of the first prism 3, where the beam splitter 10 is located. This allows for the reflection of the virtual imaging light 6, performing the first light folding. The reflected virtual imaging light 6 passes again through the phase retarder 9 and is converted back into linearly polarized light, then reflected again by the polarization reflection film 8, and finally exits through the first prism 3 into the human eye (see...). Figure 1 (Medium aperture 2) to complete the second light folding.

[0065] The following is a detailed explanation of the functions of the three optical film materials mentioned above.

[0066] The polarization reflection element 8 and the phase delayer 9 are sequentially disposed between the first prism 3 and the second prism 4, and the phase delayer 9 is located in the optical path between the beam splitter 10 and the polarization reflection element 8.

[0067] The synergistic effect of the polarization reflection element 8 and the phase delayer 9 enables the virtual imaging light 6 emitted by the screen 5 to be efficiently converted into circularly polarized light, which is then reflected by the beam splitter 10, ultimately achieving high light energy utilization of the virtual optical path.

[0068] The combination of the polarization reflection element 8, the phase delayer 9, and the beam splitter 10 enables multiple reflections of light, making the optical path more compact and further reducing the size of the AR optical module.

[0069] The polarization reflective element 8, as one of the key optical components in the optical 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 polarization reflective element 8 can accurately control the polarization direction and propagation path of light. It is responsible for reflecting light with a specific polarization state, guiding it along a preset optical path, and effectively filtering out interfering light such as stray light, thereby ensuring image clarity.

[0070] In this application, the polarization reflective element 8 is, for example, a polarization reflective film.

[0071] The phase retarder 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 phase retarder 9 is adjusted. Figure 1 This ensures that the virtual imaging light 6 can still be accurately projected into the user's eyes after being folded multiple times (such as twice) inside the first prism 3, thus guaranteeing a high-quality visual experience.

[0072] In this application, the first phase delayer 9 is, for example, a quarter-wave plate.

[0073] The beam-splitting element 10 is disposed on one side of the lower surface of the first prism 3, see [reference]. Figure 1 It is used to reflect some light while transmitting some light, enabling the superposition of virtual and real images.

[0074] In this application, the beam splitter 10 is, for example, a semi-transparent and semi-reflective film.

[0075] In this application, the polarization reflection element 8, the first phase delayer 9, and the beam splitter 10 work together with the first prism 3 and the second prism 4 to construct a highly efficient and stable optical path folding system, providing excellent optical performance and visual experience for the AR optical module.

[0076] The AR optical module provided in this embodiment also includes a screen 5, see [link]. Figure 1 From a positional layout perspective, the screen 5 is positioned on one side of the upper surface of the second prism 4, opposite the lower surface of the first prism 3, and the central axis of the screen 5 is perpendicular to the optical axis 1. The central axis of the screen 5 refers to the axis passing through the center of the screen 5 and perpendicular to the plane containing the screen. This layout offers the following advantages:

[0077] (1) Optimize the optical path propagation path: The layout of the screen 5 enables the virtual imaging light 6 emitted by it to enter the second prism 4 efficiently, and be converted and reflected by the polarization reflection element 8 and the phase delayer 9, ensuring smooth propagation of the optical path.

[0078] (2) Compact module layout: The plane where the screen 5 is located is arranged perpendicular to the optical axis 1, which reduces the size of the module along the optical axis 1 and makes the module more compact.

[0079] The screen 5 is used to display images, and the virtual imaging light 6 emitted from it passes through an optical prism assembly consisting of the first prism 3 and the second prism 4, as well as a series of optical films (polarizing optical components). During this process, the virtual imaging light 6 undergoes two crucial refractions and reflections between the lower surface of the first prism 3 and the cemented interface between the first prism 3 and the second prism 4. It is worth noting that in the design of this application, the virtual imaging light 6 does not pass through the surface of the second prism 4 away from the aperture 2 during these two folding processes. This characteristic means that there is no need to additionally set optical films (such as quarter-wave plates and polarizing films) on the surface of the second prism 4 for filtering stray light. This design not only simplifies the structure of the AR module but also reduces manufacturing costs while maintaining excellent optical performance.

[0080] In the AR optical module provided in this application embodiment, the virtual imaging light 6 emitted by the screen 5 is folded twice within the first prism 3, and passes through the first prism 3 a total of three times. The virtual imaging light 6 passes through the first prism 3 three times with a folding thickness F. t The ratio between the total focal length F of the AR optical module and the total focal length F of the AR optical module satisfies: 1 ≤ F t / F≤1.6.

[0081] In this embodiment, the virtual imaging ray 6 is designed to be folded twice within the first prism 3, which not only reduces the size of the AR optical module but also ensures efficient light transmission. The focal length ratio range is 1 ≤ F. t The design with an F-value of ≤1.6 helps to further optimize the optical performance of the AR optical module, especially by maintaining or improving image quality while reducing size.

[0082] The combined use of the beam splitter 10 (semi-transparent and semi-reflective film), the phase delayer 9 (quarter-wave plate), and the polarization reflective element 8 (polarization reflective film) achieves an energy utilization rate of at least 50% for the virtual optical path. This allows more light to be effectively utilized, improving the brightness and contrast of the entire AR optical module.

[0083] The AR optical module provided in this application embodiment satisfies 1≤F t With / F≤1.6, this design range ensures a balance between module size, optical performance, energy efficiency, and cost.

[0084] If F t / F < 1 will lead to a decrease in the optical performance of the module. This is because:

[0085] When F tWhen the value of / F is too small, it means that the folding and transmission path of light in the first prism 3 is too compact, which may lead to an increase in optical aberrations (such as chromatic aberration, spherical aberration, etc.), thereby affecting the image quality.

[0086] Although the smaller F t The / F value helps to further reduce the module size, but if it exceeds the design limits, it may make the layout of other optical components (such as lenses, films, etc.) difficult, or even fail to meet the requirements of the overall structural design. Furthermore, an overly compact optical path may place higher demands on manufacturing precision, increasing production difficulty and cost.

[0087] If F t / F > 1.6 leads to an increase in module size. Specifically:

[0088] When F t When the value of / F is too large, the folding and transmission path of light within the first prism 3 becomes lengthy, resulting in an unnecessary increase in module size, which contradicts the design goal of miniaturization. Increased module size may mean the need for more materials and more complex manufacturing processes, leading to higher costs.

[0089] In conclusion, F t The design of the / F value requires finding a balance between ensuring optical performance, module size, manufacturing difficulty, and cost. Values ​​exceeding 1 ≤ F t A ratio of / F ≤ 1.6 can lead to a series of problems, affecting the overall performance of the AR optical module and the user's visual experience. Therefore, this ratio should be carefully controlled during the design and manufacturing process to meet optical design requirements.

[0090] It should be noted that the virtual imaging ray 6 passes through the first prism 3 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 first prism 3 and sequentially undergoing the following three transmission (and accompanying reflection) processes:

[0091] See Figure 1 The first transmission and reflection: After the virtual imaging ray 6 is emitted from the screen 5, it first becomes linearly polarized light, and then enters the second prism 4 (the folding thickness calculation starts from entering the first prism 3). After entering the second prism 4, the light is converted into circularly polarized light by the polarization reflection element 8 and the phase delayer 9, and then shines on the first prism 3. On the lower surface of the first prism 3, the light first passes through, and then encounters the beam splitter 10 and is reflected. This reflection marks the end of the first effective transmission and reflection process of the virtual imaging ray 6 in the first prism 3. The path length traversed in this process is the first part of the folding thickness Ft.

[0092] Second transmission and reflection: The reflected virtual imaging ray 6 continues to propagate inside the first prism 3, reaching the phase retarder 9 on the side of the first prism 3 away from the aperture 2. It passes through the phase retarder 9 again and then encounters the polarization reflection element 8, resulting in a second reflection. After this reflection, the virtual imaging ray 6 changes direction and propagates again towards the lower surface of the first prism 3. The path length traversed in this process is the second part of the fold thickness Ft.

[0093] Third transmission: The reflected virtual imaging ray 6 reaches the lower surface of the first prism 3 again, passes through the surface, and finally enters the aperture 2. This transmission marks the end of the third effective transmission process of light within the first prism 3, and the path length traversed in this process is the third part of the fold thickness Ft.

[0094] During these three transmission processes, the virtual imaging ray 6 is "folded" and propagates within the first prism 3 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≤1.6, this ratio is of great significance for optimizing the size and optical performance of AR modules.

[0095] This application provides an AR optical module that simplifies the optical structure through the design of two freeform prisms (first prism 3 and second prism 4) bonded together. This design significantly reduces the module's size, promotes the compact development of optical modules, and fully utilizes the advantages of freeform surfaces to significantly expand the field of view (FOV), providing users with a more immersive visual experience.

[0096] The application of freeform prisms optimizes the light propagation path and improves light energy utilization, enabling virtual images to be transmitted to the human eye more efficiently. Simultaneously, through the synergistic effect of polarization reflection elements, phase delayers, and beam splitters, this application achieves efficient energy transfer and utilization in the virtual optical path, significantly improving energy utilization and imaging performance.

[0097] In terms of optical performance, the AR optical module of this application exhibits excellent performance. The modulation transfer function (MTF) values ​​of the module at wavelengths of 450nm, 550nm and 610nm are all greater than 0.8 at a spatial frequency of 15lp / mm. This performance fully guarantees the clarity of the image.

[0098] Furthermore, the virtual imaging light folds twice within the first prism and passes through a total of three times. This design not only optimizes the optical path but also improves the imaging performance of the module by controlling the ratio between the folding thickness Ft of the virtual imaging light passing through the first prism three times and the total focal length F of the AR optical module.

[0099] In summary, the AR optical module of this application demonstrates advantages in terms of structural simplification and performance improvement. Its design concept and superior performance provide support for the development of AR technology.

[0100] In some examples of this application, the lower surface of the first prism 3 and the upper surface of the second prism 4 are both freeform surfaces, and the radius of curvature R of each freeform surface is... i The total focal length F of the AR optical module satisfies the following condition: -2≤R i / F≤5.

[0101] The freeform surface design facilitates the correction of various aberrations, such as spherical aberration, thereby improving image quality. The freeform surface design also effectively expands the module's field of view, reaching 50° or even greater, which enhances the user's immersive experience. Furthermore, the freeform surface design reduces light distortion and aberrations, ensuring high definition and color fidelity in virtual images.

[0102] In the example provided in this application, by optimizing the ratio range of the radii of curvature of the two freeform surfaces in the AR optical module to the total focal length of the AR optical module, the thickness and volume of the AR optical module can be significantly reduced while ensuring optical performance, thereby achieving a thinner and lighter AR optical module. This is crucial for AR display devices that prioritize portability and a comfortable wearing experience.

[0103] By rationally designing R i The value of / F can further optimize the modulation transfer function (MTF) of the AR optical module, ensuring high-resolution images across a wide spectral range. For example, the AR optical module provided in this application has an MTF value greater than 0.8 at a spatial frequency of 15 lp / mm at wavelengths of 450 nm, 550 nm, and 610 nm, guaranteeing image clarity and color reproduction.

[0104] If R i The value of / F exceeds the above range, such as: R i / F < -2 or R i If the f-value is greater than 5, the light path cannot be effectively folded, and the size of the AR optical module will increase, which is detrimental to portability and comfort. In addition, it may lead to insufficient aberration correction, affecting image quality, and MTF performance will decrease, resulting in problems such as reduced image resolution and color distortion.

[0105] See some examples in this application. Figure 1 The AR optical module includes an aperture 2, which is disposed along the optical axis 1 on the side of the first prism 3 away from the second prism 4. The bonding interface of the first prism 3 and the second prism 4 has the same surface shape, and 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 composed of the first prism 3 and the second prism 4 has zero transmittance.

[0106] By bonding the first prism 3 and the second prism 4 together to form an optical prism assembly, the number of individual optical elements in the AR optical module can be reduced, simplifying the integrated structure of the module's core components. This design not only reduces assembly complexity but also reduces air gaps between optical elements, thereby reducing light reflection and scattering and improving the overall optical efficiency of the AR optical module.

[0107] See Figure 1 The AR optical module further includes an aperture stop 2, which serves as an exit pupil stop and is positioned along the optical axis 1 on the side of the first prism 3 facing away from the second prism 4. In this application, the primary function of the aperture stop 2, as the exit pupil stop, is to determine the position and size of the exit pupil of the AR optical module. The exit pupil is the position where the user's eyes can see a clear image; its size and position directly affect the user's visual comfort and the application range of the AR optical module.

[0108] The aperture 2 provided in this application example can limit the range of light entering the user's eye, ensuring that light is evenly distributed at the exit pupil. This helps reduce glare and ghosting, and improves the comfort and clarity of the visual experience.

[0109] 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 design of the optical prism assembly can effectively improve the performance of the optical system.

[0110] The identical surface design of the bonding interface allows the first prism 3 and the second prism 4 to form a tighter and more stable structure during bonding. This helps to resist the effects of external environmental factors (such as changes in temperature and humidity) on the module's performance, ensuring that the AR optical module maintains stable optical performance under various conditions.

[0111] In addition, matching the face shape helps reduce errors and deviations that may occur during prism assembly, because prisms with the same face shape are easier to align and fix precisely.

[0112] In the AR optical module provided in this application, light needs to be folded through a prism and optical film to display virtual images. The matching surface design helps optimize the folding path of the light, allowing it to be transmitted to the user's eyes more efficiently. This not only improves the brightness of the virtual image but also reduces light loss and interference during transmission, thereby enhancing the visual experience.

[0113] In this example of the application, the transmittance of the optical prism assembly is zero. Zero transmittance means that the prism assembly does not produce any additional focusing or diverging effect on light. This helps eliminate aberrations and distortions caused by improper prism material or surface design, thereby ensuring that the AR optical module can provide clear and accurate virtual image display.

[0114] When the transmittance of the optical prism assembly is zero, light rays maintain their original propagation direction and energy distribution as they pass through the prism. This helps reduce light loss due to reflection, scattering, and absorption within the prism, thereby improving light transmission efficiency. This is significant for enhancing the brightness and contrast of virtual images.

[0115] The design of optical prism components with zero optical power facilitates the miniaturization and weight reduction of AR optical modules. Since the prism does not produce additional focusing effect on light, the size and weight of the module can be reduced by optimizing the size and shape of the prism while maintaining optical performance.

[0116] 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 perpendicular to the transmission axis of the polarizing reflection element 8.

[0117] The AR optical module further includes a first polarizing element 7, which is directly disposed on the surface of the first prism 3 near the aperture 2, and the transmission axis of the first polarizing element 7 is perpendicular to the transmission axis of the polarizing reflective element 8. The first polarizing element 7 is, for example, a polarizing film. A polarizing film (such as a polarizer) is an optical element capable of selectively transmitting light polarized in a specific direction.

[0118] In the AR optical module provided in this application, the first polarizing element 7 is used to control the polarization state of the light 6.

[0119] In this application, the transmission axis of the first polarizing element 7 is perpendicular to the transmission axis of the polarizing reflective element 8. This design allows for control of the polarization state of light. This orthogonal polarization design effectively separates and filters light rays with different polarization directions, ensuring that only light rays with specific polarization directions can pass through or be reflected, thereby improving the light control accuracy of the AR optical module.

[0120] In this application, by setting the first polarizing element 7 perpendicular to the transmission axis of the polarizing reflective element 8, stray light and unwanted polarized light can be effectively 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.

[0121] The orthogonal polarization design of the first polarizing element 7 and the polarizing reflective element 8 effectively reduces light reflection and scattering, thus lowering light energy loss. This design ensures that more light is effectively utilized, improving the overall efficiency of the AR optical module and thereby enhancing display brightness and image quality.

[0122] In the AR optical module provided in this application embodiment, the superposition of virtual and real images requires precise polarization management. By setting the first polarizing element 7 perpendicular to the transmission axis of the polarizing reflective element 8, it can be ensured that the light from the virtual image and the light from the real environment are effectively separated in polarization, avoiding polarization interference and improving the overall performance of the module.

[0123] See some examples in this application. Figure 1 The polarization reflection element 8 and the phase delayer 9 are stacked and form a composite element, and the composite element is disposed at the bonding interface between the first prism 3 and the second prism 4; the beam splitter 10 is disposed on the lower surface of the first prism 3.

[0124] In this application, the arrangement of the superimposed element (which mainly consists of a polarization reflector 8 and a phase retarder 9) enables light to undergo polarization state conversion and reflection when passing through the optical prism assembly (especially the first prism 3), thereby achieving effective light folding. This design helps guide virtual image light to the correct position in the user's eye while maintaining the polarization state of the light to reduce stray light interference.

[0125] The polarization reflector 8 can selectively reflect light with a specific polarization direction, while the phase delayer 9 can change the polarization state of the light. This combination allows the light to undergo a complex polarization conversion process inside the prism, thereby enhancing the AR module's ability to control the polarization state of the light.

[0126] By designing the positions and parameters of the superimposed element and the beam splitter 10, light loss inside the prism can be minimized. The arrangement of the superimposed element helps ensure that light maintains a high energy level during reflection and transmission, while the beam splitter 10 can rationally distribute light energy to achieve the superimposed display of virtual and real images.

[0127] Furthermore, the combination of the polarization reflective element 8 and the phase delayer 9 helps to reduce the reflection and scattering loss of light at the cemented interface of the two prisms, further improving the light energy utilization rate.

[0128] Combining the polarizing reflective element 8 and the phase retarder 9 into a stacked element and placing it on the cemented interface of the two prisms helps simplify the structure of the AR optical module. This design reduces the number of individual optical elements in the module and the complexity of assembly, lowers manufacturing costs, and improves the reliability and stability of the module.

[0129] In some examples of this application, the effective focal length F1 of the first prism 3 and the total focal length F of the AR optical module satisfy: 1≤F1 / F≤1.5.

[0130] When the ratio of the effective focal length F1 of the first prism 3 to the total focal length F of the AR optical module is between 1 and 1.5, the propagation path of light within the module is optimized, reducing aberrations and distortions, thereby improving the clarity and accuracy of the image. This ratio helps balance the focusing and diffusion of light, allowing the virtual image to be presented more accurately to the user.

[0131] By properly controlling the ratio of F1 to F, the optical performance of the module can be optimized to a certain extent, including key indicators such as modulation transfer function (MTF), distortion, and spot diagram. Improvements in these indicators mean that the module performs better in terms of image quality, color reproduction, and contrast, providing users with a superior visual experience.

[0132] While maintaining image quality, adjusting the ratio of F1 to F can reduce the module's size to some extent. This is because a reasonable focal length ratio helps optimize the optical path design, reducing unnecessary space occupation and thus achieving a compact and lightweight module. This is especially important for AR devices, as a compact module design helps improve the device's portability and comfort.

[0133] The optimized module offers a wider field of view (FOV) and a more immersive visual experience. Users will experience a more realistic fusion of virtual and real-world visuals when using AR devices, thus enhancing the overall user experience.

[0134] See some examples in this application. Figure 1 A second polarizing element 11 is provided on the light-emitting surface of the screen 5 to convert the virtual imaging light 6 emitted by the screen 5 into linearly polarized light.

[0135] The second polarizing element 11 is 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 the AR optical module provided in this application, the second polarizing element 11 is used to control the polarization state of light in order to achieve specific optical effects.

[0137] The virtual imaging light 6 emitted by the screen 5 is converted into linearly polarized light after passing through the second polarizing element 11. This conversion process helps reduce stray components in the light, allowing more effective light to be utilized by subsequent optical elements, thereby improving the light utilization rate of the entire AR optical module.

[0138] In the AR optical module of this application, polarization management is one of the key factors for achieving high-quality display. The setting of the second polarizing element 11 ensures that the virtual imaging light 6 emitted by the screen 5 has a defined polarization state, providing stable input conditions for subsequent optical elements such as the polarization reflection element 8 and the phase delayer 9. This helps optimize the polarization performance of the entire AR optical module and ensures the correct display of the virtual image.

[0139] Of course, if the screen 5 can directly emit linearly polarized light, the second polarizing element 11 mentioned above can be omitted.

[0140] In some examples of this application, the virtual imaging light 6 emitted by the screen 5 is converted into linearly polarized light and then enters the second prism 4. The linearly polarized light is converted into circularly polarized light after passing through the polarization reflection element 8 and the phase delayer 9. The circularly polarized light is incident on the beam splitter 10 on one side of the lower surface of the first prism 3 and is reflected. The reflected circularly polarized light is converted into linearly polarized light again after passing through the phase delayer 9, and after being reflected by the polarization reflection element 8, it finally exits through the first prism 3. In this process, the virtual imaging light 6 is folded twice in the first prism 3 and passes through the first prism 3 a total of three times.

[0141] Based on the example provided in this application, see [link / reference]. Figure 1 The path of light can be divided into the following steps.

[0142] (1) Light conversion and entry into the prism:

[0143] The virtual imaging light 6 emitted by the screen 5 is first processed by optical elements and converted into linearly polarized light. The converted linearly polarized light then enters the second prism 4.

[0144] (2) Light processing within the prism:

[0145] The virtual imaging light 6, within the second prism 4 near the aperture 2, is converted into circularly polarized light by the polarization reflection element 8 (polarization reflection film) and the phase delayer 9 (1 / 4 phase delay film or 1 / 4 wave plate). The circularly polarized light is then incident on the beam splitter 10 (semi-transparent and semi-reflective film) on the lower surface of the first prism 3.

[0146] (3) Reflection and further processing of light:

[0147] The circularly polarized light is reflected by the beam splitter 10, and then passes through the phase delayer 9 again, where it is converted into linearly polarized light. The converted linearly polarized light is then reflected by the polarization reflection element 8, ready for emission.

[0148] (4) Folding and transmission of light:

[0149] During this process, the virtual imaging ray 6 is folded twice within the first prism 3, passing through the first prism 3 a total of three times. In this embodiment, the focal length F of the virtual imaging ray 6 from the screen 5 passing through the first prism 3 three times is designed to be... t The total focal length F of the AR optical module must satisfy a specific ratio range, i.e., 1 ≤ F. t / F≤1.6.

[0150] By designing the lower surface of the first prism 3 and the upper surface of the second prism 4 as freeform surfaces, the size of the module can be effectively reduced while maintaining its optical performance. This is because the freeform surface design allows for more flexible control of the light path, making the module more structurally compact.

[0151] The AR optical module provided in this application has a modulation transfer function (MTF) value greater than 0.8 at wavelengths of 450nm, 550nm, and 610nm at a spatial frequency of 15lp / mm.

[0152] The modulation transfer function (MTF) is an important indicator of the imaging quality of an optical system, reflecting its ability to transmit object details at different spatial frequencies. A higher MTF value (closer to 1) indicates a stronger ability to transmit details and a clearer image. In this example, the AR optical module of this application has MTF values ​​greater than 0.8 at wavelengths of 450nm, 550nm, and 610nm. This means that the module can transmit image details with high fidelity and achieve high-resolution imaging.

[0153] 450nm, 550nm, and 610nm represent the main component wavelengths of blue, green, and red light, respectively, covering the main range of visible light. The AR optical module of this application exhibits excellent MTF performance at all three wavelengths, ensuring image clarity and consistency across different color channels, thereby improving color reproduction.

[0154] A high MTF value typically indicates effective control of distortion and aberrations in an optical system. In this application, the AR optical module maintains a high MTF value across different wavelengths, reflecting the module design's excellent performance in reducing distortion and aberrations. Low distortion and low aberrations contribute to improving the realism of virtual images and the viewer's visual comfort.

[0155] By testing MTF values ​​at multiple key wavelengths, this application demonstrates the AR optical module's adaptability to a wide spectrum. This means that the optical module can maintain stable imaging quality under different lighting conditions.

[0156] High resolution, high color fidelity, and low distortion imaging quality are key factors in augmented reality (AR) applications. The AR optical module provided in this application, by offering excellent MTF performance, helps to improve the visual experience of AR applications, making virtual images more realistic and natural, and enhancing their integration with the real world.

[0157] 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.

[0158] The AR display device is, for example, a smart head-mounted device, such as AR smart glasses or AR smart helmet.

[0159] According to another embodiment of this application, an imaging display method for an AR optical module is provided, comprising the following steps 100 to 400:

[0160] Step 100: The virtual imaging light 6 emitted from screen 5 passes through the second polarizing element 11 and becomes linearly polarized light;

[0161] Step 200: After the linearly polarized light enters the second prism 4, it becomes circularly polarized light after passing through the polarization reflection element 8 and the phase retarder 9.

[0162] Step 300: The circularly polarized light is incident on the beam-splitting element 10 on the lower surface of the first prism 3 and is reflected;

[0163] Step 400: The circularly polarized light that has been reflected passes through the phase delayer 9 again to become linearly polarized light. This linearly polarized light is then reflected by the polarization reflection element 8 and finally exits through the first prism 3.

[0164] The virtual imaging light 6 emitted by the screen 5 is folded twice within the first prism 3, passing through the first prism 3 a total of three times, and the virtual imaging light 6 passes through the first prism 3 three times with a folding thickness F. t The ratio between the total focal length F of the AR optical module and the total focal length F of the AR optical module satisfies: 1 ≤ F t / F≤1.6.

[0165] Regarding the imaging and display method of the AR optical module provided in the embodiments of this application, the following is an analysis of each step and a description of its technical effects or functions.

[0166] Regarding step 100, it is described that the virtual imaging light 6 emitted by the screen 5 passes through the second polarizing element 11 and becomes linearly polarized light. Here, the screen 5 acts as an image source, and the virtual imaging light 6 emitted by it is first converted into linearly polarized light after passing through the second polarizing element 11. This design ensures that subsequent optical elements can correctly process and reflect the light. After processing by the second polarizing element 11, it helps reduce stray light interference and improve the clarity and contrast of the image.

[0167] Regarding step 200, it is described that after the linearly polarized light enters the second prism 4, it becomes circularly polarized light after passing through the polarization reflection element 8 and the phase delayer 9. Circularly polarized light has advantages in terms of anti-reflection and glare reduction.

[0168] In this application, by using specific polarization and phase delay processing, light can be effectively utilized, light loss can be reduced, and the overall efficiency of the AR optical module can be improved.

[0169] Regarding step 300, it is described that the circularly polarized light is incident on the beam-splitting element 10 on the lower surface of the first prism 3 and is reflected. This step achieves light folding, that is, guiding the light from one direction to another, thereby allowing complex AR optical modules to be built in a smaller space.

[0170] Through the reflection of the beam splitter 10, light is effectively guided into the user's eyes, forming a virtual image display effect.

[0171] Regarding step 400, it is described that the reflected circularly polarized light passes through the phase retarder 9 on the side of the first prism 3 away from the aperture 2, becoming linearly polarized light. That is, the reflected circularly polarized light passes through the phase retarder 9 again and is converted into linearly polarized light. This step provides the necessary conditions for subsequent polarized reflection. By converting it back into linearly polarized light, it is ensured that the light maintains a consistent polarization state during subsequent propagation, thereby improving the stability and sharpness of the image.

[0172] Step 400 further describes how the formed linearly polarized light, after being reflected by the polarization reflection element 8, is reflected by the first polarizing element 7 on the side of the first prism 3 near the aperture 2, and then exits to the aperture 2, ultimately forming an image. This step is the final step in the AR optical module imaging process, ensuring that the virtual image can be correctly displayed in the user's field of vision.

[0173] Through precise light processing and reflection, AR optical modules can provide users with clear and realistic virtual images, thereby enhancing their visual experience.

[0174] The imaging and display method of the AR optical module provided in this application achieves high-quality virtual image display through a series of light processing and reflection steps. Each step plays an important role and together constitutes a complete and efficient AR optical module.

[0175] The AR optical module of this application will be described in detail below through Examples 1 to 3.

[0176] Example 1

[0177] See Figure 1 The AR optical module provided in this embodiment 1 includes the following optical elements:

[0178] An optical prism assembly, including a first prism 3 and a second prism 4 bonded together along the same optical axis 1, is used to transmit real images and fold virtual imaging rays 6 from a screen;

[0179] The polarization reflective element 8 and the phase retarder 9 form a superimposed element and are disposed on the adhesive interface between the first prism 3 and the second prism 4.

[0180] The beam splitter 10 is disposed on the lower surface of the first prism 3, and the phase delayer 9 is located in the optical path between the beam splitter 10 and the polarization reflection element 8;

[0181] Screen 5 is disposed on one side of the upper surface of the second prism 4 and opposite to the lower surface of the first prism 3, and the central axis of the screen 5 is perpendicular to the optical axis 1;

[0182] Aperture 2 is disposed along the optical axis 1 on the side of the first prism 3 opposite to the second prism 4;

[0183] The lower surface of the first prism 3 and the upper surface of the second prism 4 are both freeform surfaces;

[0184] The virtual imaging light 6 emitted from the screen 5 is converted into linearly polarized light and then enters the second prism 4. The virtual imaging light 6 is converted into circularly polarized light by the polarization reflection element 8 and the phase retarder 9. The circularly polarized light is incident on the beam splitter 10 on the lower surface of the first prism 3, reflected, and then converted back into linearly polarized light by the phase retarder 9. After being reflected by the polarization reflection element 8, it exits. During this process, the virtual imaging light 6 is folded twice within the first prism 3 and passes through the first prism 3 a total of three times. The folding thickness F of the virtual imaging light 6 passing through the first prism 3 three times is... t The ratio of the total focal length F of the entire AR optical module is 1.6;

[0185] The bonding interface of 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 transmittance of the optical prism assembly composed of the first prism 3 and the second prism 4 is zero.

[0186] The AR optical module includes a first polarizing element 7, which is disposed on the surface of the first prism 3 near the aperture 2. The transmission axis of the first polarizing element 7 is perpendicular to the transmission axis of the polarizing reflection element 8.

[0187] A second polarizing element 11 is provided on the light-emitting surface of the screen 5 to convert the light 6 emitted by the screen 5 into linearly polarized light.

[0188] Please refer to Table 1 below for the optical parameters of the AR optical module provided in this embodiment 1.

[0189] Table 1

[0190]

[0191] Document Classification: Confidential

[0192]

[0193] Figures 3a-3c The modulation transfer function (MTF) curves of the AR optical module provided in Example 1 are shown at 450nm, 550nm, and 610nm, respectively. Figures 3a-3cIt can be seen that at a spatial frequency of 15 lp / mm, the MTF value of the AR optical module is higher than 0.9 at a wavelength of 450 nm, at a wavelength of 550 nm, and at a wavelength of 610 nm.

[0194] 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%.

[0195] 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 As can be seen, at a wavelength of 450nm, the RMS radius of the AR optical module is less than 4mm; at a wavelength of 550nm, the RMS radius of the AR optical module is less than 4mm; and at a wavelength of 610nm, the RMS radius of the AR optical module is less than 6mm.

[0196] Example 2

[0197] 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 1.0; and the optical parameters are designed as follows, please refer to Table 2 for details;

[0198] Table 2

[0199]

[0200]

[0201] 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-7c It can be seen that at a spatial frequency of 15 lp / mm, the MTF value of the AR optical module is higher than 0.9 at a wavelength of 450 nm, higher than 0.9 at a wavelength of 550 nm, and higher than 0.8 at a wavelength of 610 nm.

[0202] Figures 8a-8cThe 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%.

[0203] Figures 9a-9c Dot plots of the AR optical module provided in Embodiment 2 at 450nm, 550nm, and 610nm respectively, from Figures 9a-9c As can be seen, at a wavelength of 450nm, the RMS radius of the AR optical module is less than 3mm; at a wavelength of 550nm, the RMS radius of the AR optical module is less than 4mm; and at a wavelength of 610nm, the RMS radius of the AR optical module is less than 5mm.

[0204] Example 3

[0205] 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 1.3; and the optical parameters are designed as follows, please refer to Table 3 for details;

[0206] Table 3

[0207]

[0208]

[0209] Figures 11a-11c The modulation transfer function (MTF) curves of the AR optical module provided in this embodiment 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 0.9 at a wavelength of 450 nm, at a wavelength of 550 nm, and at a wavelength of 610 nm.

[0210] Figures 12a-12c The distortion curves of the AR optical module provided in Example 3 at 450nm, 550nm, and 610nm are shown respectively. Figures 12a-12cIt can be seen that: at a wavelength of 450nm, the distortion value of the AR optical module is less than 3%; at a wavelength of 550nm, the distortion value of the AR optical module is less than 3%; and at a wavelength of 610nm, the distortion value of the AR optical module is less than 3%.

[0211] 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 of the AR optical module is less than 3mm; at a wavelength of 550nm, the RMS radius of the AR optical module is less than 4mm; and at a wavelength of 610nm, the RMS radius of the AR optical module is less than 5mm.

[0212] 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.

[0213] 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.

[0214] 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). The lower surface of the first prism (3) and the upper surface of the second prism (4) are both freeform surfaces, and the radius of curvature of each freeform surface is... R i Total focal length of the AR optical module F The following condition must be met: -2≤ R i / F ≤5, the optical prism assembly is used to transmit real ambient light and fold virtual imaging light (6) from the screen (5); The polarization optical component includes a polarization reflection element (8) and a phase retarder (9) disposed between the first prism (3) and the second prism (4), and a beam splitter (10) disposed on one side of the lower surface of the first prism (3), wherein the phase retarder (9) is located in the optical path between the beam splitter (10) and the polarization reflection element (8); The screen (5) is disposed on one side of the upper surface of the second prism (4) and opposite to the lower surface of the first prism (3), 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 first prism (3), and passes through the first prism (3) a total of three times. The virtual imaging light (6) passes through the first prism (3) three times in terms of folding thickness. F t Total focal length of the AR optical module F The ratio between them satisfies: 1 ≤ F t / F ≤1.

6.

2. The AR optical module according to claim 1, characterized in that, The AR optical module includes an aperture stop (2), which is disposed along the optical axis (1) on the side of the first prism (3) away from the second prism (4); The bonding interface of the first prism (3) and the second prism (4) has the same surface shape, and 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 composed of the first prism (3) and the second prism (4) has zero transmittance.

3. The AR optical module according to claim 2, 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 the transmission axis of the first polarizing element (7) is perpendicular to the transmission axis of the polarizing reflection element (8).

4. The AR optical module according to claim 1, characterized in that, The polarization reflection element (8) and the phase delayer (9) are stacked and form a composite element, which is disposed at the bonding interface between the first prism (3) and the second prism (4). The beam splitting element (10) is disposed on the lower surface of the first prism (3).

5. The AR optical module according to claim 1, characterized in that, The effective focal length of the first prism (3) F 1 and the total focal length of the AR optical module F Satisfy: 1≤ F 1 / F ≤1.

5.

6. The AR optical module according to claim 1, characterized in that, A second polarizing element (11) is provided on the light-emitting surface of the screen (5), and the second polarizing element (11) is configured to convert the virtual imaging light (6) emitted by the screen (5) into linearly polarized light.

7. The AR optical module according to claim 1 or 6, characterized in that, The virtual imaging light (6) emitted by the screen (5) is converted into linearly polarized light and then enters the second prism (4). The linearly polarized light is converted into circularly polarized light by the polarization reflection element (8) and the phase delayer (9). The circularly polarized light is incident on the beam splitter (10) on one side of the lower surface of the first prism (3) and is reflected. The reflected circularly polarized light is converted into linearly polarized light again by the phase delayer (9), and after being reflected by the polarization reflection element (8), it finally exits through the first prism (3). In this process, the virtual imaging light (6) is folded twice in the first prism (3) and passes through the first prism (3) a total of three times.

8. An AR display device, characterized in that, include: shell; and The AR optical module as described in any one of claims 1-7.

9. An imaging display method for an AR optical module as described in any one of claims 1-7, characterized in that, include: The virtual imaging light (6) emitted from the screen (5) passes through the second polarizing element (11) and becomes linearly polarized light; After the linearly polarized light enters the second prism (4), it becomes circularly polarized light after passing through the polarization reflection element (8) and the phase retarder (9); The circularly polarized light is incident on the beam-splitting element (10) on the lower surface of the first prism (3) and is reflected; The circularly polarized light that has been reflected passes through the phase delayer (9) again and becomes linearly polarized light. This linearly polarized light is then reflected by the polarization reflection element (8) and finally exits through the first prism (3). The virtual imaging light (6) emitted by the screen (5) is folded twice within the first prism (3), and passes through the first prism (3) a total of three times. The virtual imaging light (6) passes through the first prism (3) three times in terms of folding thickness. F t Total focal length of the AR optical module F The ratio between them satisfies: 1 ≤ F t / F ≤1.6.

Images