Optical module and smart head-mounted device

Abstract

The embodiment of the present application provides an optical module and an intelligent head-mounted device; the optical module comprises a first optical assembly, a second optical assembly and a third optical assembly which are arranged along the same optical axis from the side of a human eye to the side of an image source; the first optical assembly comprises a prescription lens, and the prescription lens has a negative optical power; the second optical assembly comprises a first lens, a reflective polarizing element arranged on at least one side of the first lens and a phase retardation plate, and the first lens has a positive optical power; the third optical assembly comprises a second lens and a light splitting element arranged on one side of the second lens, and the second lens has a positive optical power; the phase retardation plate is located between the light splitting element and the reflective polarizing element; the distance between the surface of the prescription lens away from the first lens and the surface of the first lens close to the prescription lens along the optical axis direction is TD, the center thickness of the prescription lens is CT1, and 8.5 < TD / CT1 < 12.5.

Description

Technical Field

[0001] This application relates to the field of optical display technology, and more specifically, to an optical module and a smart head-mounted device. Background Technology

[0002] Currently, prescription lenses (R) x Prescription lenses are primarily designed for correcting vision problems such as myopia and astigmatism. However, in VR head-mounted display devices, prescription lenses (R) are... x Prescription lenses (R) and VR optical modules are usually designed separately. x The focus of prescription lenses is primarily on vision correction, without considering their impact on the overall optical performance of the module when integrated into it. In reality, when prescription lenses (R...)... x When a lens is introduced into a pre-designed VR optical module, it may lead to a decrease in performance indicators such as distortion and sharpness, thereby affecting the user's visual experience. Summary of the Invention

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

[0004] In a first aspect, this application provides an optical module. The optical module includes a first optical component, a second optical component, and a third optical component arranged sequentially along the same optical axis from the human eye side to the image source side;

[0005] The first optical component includes a prescription lens having negative power, the prescription lens being used to match the user's vision.

[0006] The second optical component includes a first lens and a reflective polarizing element and a phase retarder disposed on at least one side of the first lens, wherein the first lens has positive optical power;

[0007] The third optical component includes a second lens and a beam splitter disposed on one side of the second lens. The second lens has positive optical power, and the phase retarder is located between the beam splitter and the reflective polarizing element.

[0008] The distance along the optical axis between the surface of the prescription lens furthest from the first lens and the surface of the first lens closest to the prescription lens is TD, and the center thickness of the prescription lens is CT1, 8.5. <TD / CT1<12.5。

[0009] Optionally, the center thickness CT1 of the prescription lens and the center thickness CT2 of the first lens satisfy the following condition: 1.7 < |(CT1+CT2) / (CT1-CT2)| < 2.5.

[0010] Optionally, the following condition is satisfied between the central thickness CT2 of the first lens and the central thickness CT3 of the second lens: 9.5 < |(CT2 + CT3) / (CT2 - CT3)| < 10.5.

[0011] Optionally, the following condition is satisfied for the optical module: 1.0 < (L1 + L2) / (L1 - L2) < 1.5; where L1 is the effective focal length of the first lens and L2 is the effective focal length of the second lens.

[0012] Optionally, the surface of the first lens close to the prescription lens and the surface of the second lens far from the prescription lens are aspherical surfaces.

[0013] Optionally, the curvature of the surface of the first lens far from the prescription lens is C 12 and the curvature of the surface of the second lens close to the prescription lens is C 21 , 0.8 < C 12 / C 21 < 1.2.

[0014] Optionally, the following condition is satisfied for the optical module: 4.5 < f / EPD < 6.0; where f is the effective focal length of the optical module and EPD is the entrance pupil diameter of the optical module.

[0015] Optionally, the following condition is satisfied for the optical module: 11.5 < f / BFL < 12.5; where f is the effective focal length of the optical module and BFL is the distance from the second lens to the image plane.

[0016] Optionally, the optical module further includes a display screen. The display screen is located on the image source side. The display screen is adjacent to and spaced apart from the second lens along the optical axis. The display screen is used to emit light for imaging display.

[0017] Optionally, the beam splitting element is located on the side of the second lens close to the display screen;

[0018] The reflective polarization element and the phase retardation plate are located between the first lens and the second lens.

[0019] Optionally, the beam splitting element is disposed on the surface of the second lens on the side close to the display screen;

[0020] The reflective polarization element and the phase retardation plate form a composite film material and are disposed on the surface of the first lens on the side close to the display screen.

[0021] Optionally, the diopter DS of the prescription lens is: -1.0D to -8.0D, and the central thickness T1 of the prescription lens is 1.4 mm ≤ T1 ≤ 3.2 mm;

[0022] The refractive index n1 of the prescription lens is 1.595≤n1≤1.74, and the Abbe number of the prescription lens is 32 to 46.

[0023] Optionally, the optical module further includes a third lens, which is disposed between the second optical component and the third optical component along the optical axis.

[0024] Secondly, this application provides a smart head-mounted device. The smart head-mounted device includes:

[0025] The outer casing; and

[0026] The optical module as described in the first aspect.

[0027] The beneficial effects of this application are as follows:

[0028] The optical module provided in this application is an optical module with diopter adjustment function. This optical module can reduce the decline in optical module performance caused by the addition of prescription lenses while ensuring vision correction function, thereby improving overall image quality. Furthermore, the optical module provided in this application has a compact structure and high integration, making it suitable for various smart head-mounted devices.

[0029] 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

[0030] 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.

[0031] Figure 1 This is one of the structures and optical path diagrams of the optical module provided in the embodiments of this application;

[0032] Figure 2 for Figure 1 The dot array diagram of the optical module is shown;

[0033] Figure 3 for Figure 1 The MTF diagram of the optical module is shown.

[0034] Figure 4 for Figure 1 The field curvature distortion diagram of the optical module is shown;

[0035] Figure 5 for Figure 1 The transverse chromatic aberration diagram of the optical module is shown;

[0036] Figure 6This is the second structure and optical path diagram of the optical module provided in the embodiments of this application;

[0037] Figure 7 for Figure 2 The dot array diagram of the optical module is shown;

[0038] Figure 8 for Figure 2 The MTF diagram of the optical module is shown.

[0039] Figure 9 for Figure 2 The field curvature distortion diagram of the optical module is shown;

[0040] Figure 10 for Figure 2 The transverse chromatic aberration diagram of the optical module is shown.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1. Prescription lens; 11. First surface; 12. Second surface;

[0043] 2. First lens; 21. Third surface; 22. Fourth surface;

[0044] 3. Reflective polarizing element; 4. Phase retardation plate;

[0045] 5. Second lens; 51. Fifth surface; 52. Sixth surface;

[0046] 6. Beam splitter; 7. Display screen;

[0047] 01. The human eye. Detailed Implementation

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] The optical module and smart head-mounted device provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0054] According to one embodiment of this application, an optical module is provided, see [link to relevant documentation]. Figure 1 The optical module includes a first optical component, a second optical component, and a third optical component arranged sequentially along the same optical axis from the human eye side to the image source side. The first optical component includes a prescription lens 1 with negative optical power, used to match the user's vision. The second optical component includes a first lens 2 and a reflective polarizing element 3 and a phase retarder 4 disposed on at least one side of the first lens 2, the first lens 2 having positive optical power. The third optical component includes a second lens 5 and a beam splitter 6 disposed on one side of the second lens 5, the second lens 5 having positive optical power, and the phase retarder 4 located between the beam splitter 6 and the reflective polarizing element 3. The distance along the optical axis between the surface of the prescription lens 1 away from the first lens 2 and the surface of the first lens 2 near the prescription lens 1 is TD, and the center thickness of the prescription lens 1 is CT1, 8.5. <TD / CT1<12.5。

[0055] This application provides an optical module for a VR smart head-mounted display device, which specifically includes a prescription lens 1 (R) for diopter (e.g., myopia) adjustment. x The document describes the optical architecture of the optical module and the focal length relationships between some components.

[0056] See Figure 1 The optical module provided in this application includes a first optical component, a second optical component, and a third optical component arranged sequentially along the same optical axis from the human eye side to the image source side; wherein, the first optical component includes a prescription lens 1 (R x The prescription lens 1 has negative optical power and can be used to match the user's vision, that is, to realize the vision adjustment function (such as myopia).

[0057] Optionally, the refractive power (DS) of the prescription lens 1 is -1.0D to -8.0D. The prescription lens 1 can fit most myopic users within this range of vision.

[0058] In the optical module provided in this application embodiment, the second optical component design includes a first lens 2 with positive optical power, a reflective polarizing element 3, and a phase retardation plate 4. These optical elements can work together to affect the polarization state and phase of light to achieve specific optical effects.

[0059] The reflective polarization element 3 is, for example, a polarization reflective film.

[0060] A polarizing reflective film is a type of polarizing reflector that reflects horizontally linearly polarized light and transmits vertically linearly polarized light, or reflects linearly polarized light at any other specific angle and transmits linearly polarized light perpendicular to that angle. In other words, a polarizing reflective film can reflect or transmit light according to its polarization state.

[0061] In the optical module provided in this application embodiment, the reflective polarization element 3 interacts with a specific state of polarized light (such as S-light or P-light) to achieve specific path control of the light.

[0062] The phase delay plate 4 can be used to change the polarization state of light, such as converting linearly polarized light into circularly polarized light, or converting circularly polarized light into linearly polarized light.

[0063] The phase delay plate 4 used in this application is, for example, a quarter-wave plate, which is located between the beam splitter 6 and the reflective polarizing element 3 to ensure that the light can be reflected or transmitted in subsequent paths by adjusting the phase of the light.

[0064] In the optical module provided in this application embodiment, the third optical component includes a second lens 5 with positive optical power and a beam splitter 6. The beam splitter 6 is used to split light rays into different paths, which can be used to realize image projection or display.

[0065] The beam-splitting element 6 is, for example, a thin film or coating with specific beam-splitting characteristics, which can be used to reflect and transmit incident light in a certain proportion.

[0066] The beam-splitting element 6 in this application is, for example, a semi-transparent and semi-reflective film, which allows a portion of light to pass through while reflecting the other portion.

[0067] It should be noted that the reflectivity and transmittance of the beam splitter 6 can be flexibly adjusted according to specific needs, and this embodiment does not impose any restrictions on this.

[0068] In the optical system of this embodiment, the phase retardation film 4 is located between the beam-splitting element 6 and the reflective polarizing element 3. These three optical elements, together with the first lens 2 and the second lens 5, can form a folded optical path. This folded optical path, when used with a prescription lens 1 introduced near the human eye, provides a good visual experience and can adapt to different users' vision. See also... Figure 1 , the prescription lens 1 includes two surfaces, namely a first surface 11 and a second surface 12. Among them, the first surface 11 is the surface away from the first lens 2, and the second surface 12 is the surface close to the first lens 2.

[0069] See Figure 1 , the first lens 2 includes two surfaces, namely a third surface 21 and a fourth surface 22. Among them, the third surface 21 is the surface close to the prescription lens 1, and the fourth surface 22 is the surface away from the prescription lens 1.

[0070] The distance along the optical axis between the surface of the prescription lens 1 away from the first lens 2 and the surface of the first lens 2 close to the prescription lens 1 is TD. Note that TD here includes the central thickness CT1 of the prescription lens 1.

[0071] The specific ratio range provided in the embodiments of the present application is: 8.5 < TD / CT1 < 12.5. By controlling the ratio of TD to CT1, the present application can effectively reduce the distortion introduced by the prescription lens 1 (R x Lens) in the optical module.

[0072] Distortion is one of the common optical problems in VR devices. It can cause image distortion and affect the user's visual experience. By optimizing the ratio of TD to CT1, the present application can minimize the occurrence of distortion while maintaining the myopia correction function, thereby improving the overall imaging quality.

[0073] The range of the value of TD / CT1 provided in the embodiments of the present application enables the prescription lens 1 to better adapt to the optical module. Specifically, different users may have different myopia degrees, and the thickness and position of the introduced prescription lens 1 have an important impact on its performance in the optical module. By adjusting the ratio of TD to CT1, the present application can ensure that the prescription lens 1 can maintain a good match with the optical module at different myopia degrees, thereby providing a consistent and high-quality visual experience.

[0074] A reasonable ratio of TD to CT1 helps to achieve a more reasonable distribution of optical power in the optical module. A reasonable distribution of optical power is one of the keys to ensuring the imaging quality of VR devices. By adjusting this ratio, the present application can optimize the propagation path of light in the optical module, reduce the loss and distortion of light during propagation, and thus improve the overall performance of the optical module.

[0075] When the TD / CT1 value is too small, such as less than 8.5, it means that the distance between the prescription lens 1 and the first lens 2 is relatively close, which will lead to an increase in distortion introduced by the prescription lens 1 in the optical module. Distortion is a common optical problem in VR devices, which can cause image distortion and reduce the user's visual experience.

[0076] A smaller TD / CT1 value may also make it difficult for the prescription lens 1 to maintain a good match with the optical module at different myopia degrees. This may cause discomfort for the user when using the optical module, or result in differences in image quality due to different myopia degrees.

[0077] The close proximity between the prescription lens 1 and the first lens may affect the proper allocation of optical power within the optical module. Proper allocation of optical power is crucial for ensuring the imaging quality of VR devices; improper allocation can lead to a decline in image quality.

[0078] When the TD / CT1 value is too high, it means that the distance between the prescription lens 1 and the first lens 2 is relatively large, which may lead to an increase in the overall size of the optical module. An increased system size may make it inconvenient for users to wear and use, reducing the portability of the device. Furthermore, an excessively large distance between the prescription lens 1 and the first lens 2 may affect the propagation path of light within the optical module, potentially causing more light loss and distortion during propagation, thereby reducing the overall performance of the optical module.

[0079] Therefore, a TD / CT1 ratio between 8.5 and 12.5 can achieve multiple technical benefits, including reducing distortion, improving adaptability, optimizing optical power distribution, and maintaining a suitable module size. However, a ratio less than 8.5 or greater than 12.5 may lead to increased distortion, poor adaptability, unreasonable optical power distribution, increased module size, and decreased performance. Therefore, it is crucial to control the TD / CT1 ratio during the design and manufacturing of optical modules to ensure overall performance and user experience.

[0080] The optical module provided in this application not only realizes the myopia adjustment function, but also improves the wearing comfort and visual experience of the VR headset by optimizing optical performance and reducing the size of the optical module.

[0081] In other words, the optical module provided in this application embodiment is an optical module with diopter adjustment function. This optical module can reduce the decline in optical module performance caused by the addition of prescription lenses while ensuring vision correction function, thereby improving overall image quality. In addition, the optical module provided in this application embodiment has a compact structure and high integration, making it suitable for various smart head-mounted devices.

[0082] In some examples of this application, the center thickness CT1 of the prescription lens 1 and the center thickness CT2 of the first lens 2 satisfy the following: 1.7 < |(CT1+CT2) / (CT1-CT2)| < 2.5.

[0083] According to this example of the application, the condition 1.7 < |(CT1+CT2) / (CT1-CT2)| < 2.5 sets the relative relationship between the center thickness CT1 of the prescription lens 1 and the center thickness CT2 of the first lens 2. This specific ratio range is designed to achieve specific optical performance in the optical module, such as controlling primary aberrations such as spherical aberration and chromatic aberration, while maintaining the overall compactness of the optical module.

[0084] Specifically, by precisely controlling the ratio of CT1 to CT2, the refraction angle and path of light passing through different lenses can be adjusted, thereby effectively reducing distortion and aberrations during imaging. This is especially important for systems requiring high-precision imaging.

[0085] A suitable thickness ratio helps to minimize the overall system length of the optical module while maintaining its optical performance. This is an important consideration for optical display devices that aim for miniaturization and portability.

[0086] In some examples of this application, the center thickness CT2 of the first lens 2 and the center thickness CT3 of the second lens 5 satisfy the following condition: 9.5 < |(CT2+CT3) / (CT2-CT3)| < 10.5.

[0087] Based on the condition that 1.7 < |(CT1+CT2) / (CT1-CT2)| < 2.5, when the center thickness design of the first lens 2 and the second lens 5 satisfies 9.5 < |(CT2+CT3) / (CT2-CT3)| < 10.5, the optical performance of the optical module can be further optimized by adjusting the ratio of CT2 and CT3, especially for correcting more advanced aberrations.

[0088] By combining the center thickness designs of the three lenses in the optical module of this application, the following technical effects can be achieved:

[0089] (1) Control of distortion and aberration: By simultaneously satisfying the center thickness relationship in the two examples above, the optical module can maintain high-quality imaging effect in a larger field of view and effectively reduce the impact of various aberrations on imaging quality.

[0090] (2) The system length of the optical module has been optimized: While maintaining excellent optical performance, the system length of the optical module can be minimized by controlling the center thickness relationship of each lens, which is of great significance for the design of miniaturized and lightweight optical devices.

[0091] (3) Convenience of lens processing and manufacturing: Although there are strict requirements for thickness relationship, this precise design actually provides clearer guidance for lens processing, which helps to improve processing accuracy and efficiency and reduce production costs.

[0092] In summary, the center thickness relationship in the two examples above is not only to meet specific optical performance requirements, but also to strike a balance between distortion and aberration control, system length optimization of the optical module, and ease of lens processing and manufacturing, which is the key to achieving high-performance optical modules.

[0093] If the three lenses in the optical module fail to meet the constraints of the two examples described above, a series of adverse consequences will occur. Specifically, this will first cause problems in controlling distortion and aberrations, making it difficult to guarantee image quality. Simultaneously, to meet basic optical performance requirements, the size of the optical module may need to be increased, which contradicts the current design trend towards miniaturization and lightweighting. Furthermore, the manufacturing difficulty of the lenses will also increase. Therefore, ensuring that the thickness relationship of the three lenses meets the requirements of the examples above is crucial for maintaining the overall performance of the optical module, controlling its size, and reducing manufacturing difficulty.

[0094] In some examples of this application, the optical module satisfies: 1.0 < (L1 + L2) / (L1 - L2) < 1.5; where L1 is the effective focal length of the first lens 2 and L2 is the effective focal length of the second lens 5.

[0095] According to the focal length relationship provided in the embodiments of this application: 1.0 < (L1 + L2) / (L1 - L2) < 1.5; where L1 is the effective focal length of the first lens 2 and L2 is the effective focal length of the second lens 5. This relationship helps to rationally allocate optical power and optimize the performance of the optical module.

[0096] The aforementioned focal length relationship imposes a specific proportional constraint on the effective focal lengths of the two key imaging lenses in the optical module: the first lens 2 and the second lens 5. Specifically:

[0097] The molecule (L1+L2) represents the sum of the effective focal lengths of the two lenses, reflecting the overall focal length characteristics of the optical module.

[0098] The denominator (L1-L2) represents the difference in the effective focal length of the two lenses, reflecting the distribution or difference in focal length in different parts of the optical module.

[0099] By setting upper and lower limits for this ratio (i.e., greater than 1.0 and less than 1.5), the focal length allocation of the optical module can be optimized and constrained to achieve better imaging quality and performance.

[0100] This focal length relationship in this application helps to rationally allocate optical power, allowing the optical module to maintain a balanced state in terms of overall focal length. By adjusting the focal length ratio of L1 and L2, the refraction and focusing effects of light passing through different lenses can be optimized, thereby improving image quality.

[0101] Properly setting the focal length ratio helps reduce aberrations and distortions. Aberrations and distortions are common problems in optical imaging systems, affecting image sharpness and accuracy. By adjusting the focal length ratio, light can be focused more evenly onto the image plane as it passes through the lens, thereby reducing aberrations and distortions.

[0102] For VR headsets, image quality directly impacts the user's visual experience. Optimizing the focal length relationship of the optical module can improve image quality, allowing users to obtain a clearer and more realistic visual effect when using VR headsets.

[0103] Furthermore, a well-defined focal length ratio contributes to the compactness and portability of the optical module. By optimizing the focal length ratio while maintaining a certain level of image quality, the size and weight of the lenses can be reduced, making the entire VR headset lighter and easier to carry.

[0104] When the value of (L1+L2) / (L1-L2) is too small, such as less than 1.0, it means that the focal length difference between L1 and L2 is relatively small. This may result in an unreasonable distribution of optical power between the two elements, which may lead to over-correction or under-correction of some parts of the optical module, thus affecting the overall imaging quality.

[0105] Reasonable optical power distribution and optical path reflection are key to compressing the size of VR optical modules along the optical axis. If the value of (L1+L2) / (L1-L2) is less than 1.0, it will be difficult to further compress the size of the optical module along the optical axis, which will result in VR devices being too large and inconvenient to wear and use.

[0106] Small focal length differences can make light more susceptible to interference as it propagates within the optical module, such as stray light and aberrations. These interferences can lead to a decrease in the performance of the optical module, such as reduced sharpness and increased distortion.

[0107] When the value of (L1+L2) / (L1-L2) is too large, such as greater than 1.5, it means that the focal length difference between L1 and L2 is too large, which may lead to an imbalance in the distribution of optical power between the two elements. This may also cause some parts of the optical module to be overcorrected while others are undercorrected, affecting the overall imaging effect. Excessive focal length difference may cause significant aberrations and distortions as light propagates within the module, which can impair image quality, such as blurred edges and color distortion.

[0108] Therefore, when the ratio (L1+L2) / (L1-L2) is between 1.0 and 1.5, the optical power can be reasonably allocated, the length of the optical module can be compressed, and good image quality can be maintained. If the ratio is less than 1.0 or greater than 1.5, it may lead to problems such as unreasonable allocation of optical power, difficulty in compressing the length of the optical module, performance degradation, and increased processing and manufacturing difficulty.

[0109] The optical module provided in this application embodiment has a myopia adjustment function. By including a prescription lens 1 with negative optical power, the optical module of this application can match the user's vision and realize the myopia adjustment function, so that myopic users can use VR headsets without wearing additional myopia glasses.

[0110] The optical module provided in this application embodiment can optimize the optical power distribution of the optical module by reasonably configuring the effective focal length ratio of the first lens 2 and the second lens 5, thereby improving the imaging quality and reducing distortion and aberration.

[0111] See some examples in this application. Figure 1 The surface of the first lens 2 near the prescription lens 1 and the surface of the second lens 5 away from the prescription lens 1 are aspherical.

[0112] See Figure 1 The second lens 5 includes a fifth surface 51 close to the prescription lens 1 and a sixth surface 52 away from the prescription lens 1.

[0113] Please continue reading Figure 1 The surface of the first lens 2 closest to the prescription lens 1, i.e., the third surface 21, is aspherical. The surface of the second lens 5 furthest from the prescription lens 1, i.e., the sixth surface 52, is also aspherical. This design helps to improve field curvature aberration and correct astigmatism.

[0114] Aspherical lenses have better radius of curvature characteristics and can effectively correct field curvature aberrations.

[0115] Field curvature aberration is one of the common problems in VR optical modules. It causes the image to bend to varying degrees in different areas of the field of view, affecting the user's visual experience.

[0116] By employing an aspherical design, this application can significantly reduce field curvature aberration, resulting in a flatter and clearer image throughout the entire field of view.

[0117] Besides field curvature aberration, astigmatism is another important issue to consider in optical modules. Astigmatism causes varying degrees of blurring and distortion in different directions of the field of view. In this application, the use of aspherical lenses helps correct astigmatism, improving image sharpness and clarity.

[0118] Aspherical design also helps optimize the distribution of optical power within the optical module. By adjusting the radius of curvature and other parameters of the aspherical lens, a more rational propagation path for light within the optical module can be ensured, reducing light loss and distortion during propagation. This contributes to improving the overall performance of the optical module, including contrast, resolution, and color reproduction.

[0119] The use of aspherical lenses also improves the compatibility between the prescription lens 1 and the optical module. Different users may have different myopia degrees and eye shapes, and the aspherical design can better accommodate these differences, providing a consistent and high-quality visual experience.

[0120] In addition, aspherical lenses can reduce the reflection and scattering of light on the lens surface, reducing glare and ghosting, thereby improving user comfort.

[0121] In summary, this application achieves multiple technical effects, such as improving field curvature aberration, correcting astigmatism aberration, optimizing optical power distribution, and enhancing adaptability and comfort, by employing an aspherical first lens 2 and a second lens 5. These effects collectively improve the overall performance of the optical module, providing users with a clearer, more realistic, and more comfortable visual experience.

[0122] See some examples in this application. Figure 1 The curvature of the surface of the first lens 2 away from the prescription lens 1 is C. 12 The curvature of the surface of the second lens 5 near the prescription lens 1 is C. 21 0.8 <C 12 / C 21 <1.2.

[0123] The first lens 2 is located away from the surface of the prescription lens 1, i.e., the fourth surface 22, and the second lens 5 is located close to the surface of the prescription lens 1, i.e., the fifth surface 51.

[0124] The curvature of the surface of the first lens 2 away from the prescription lens 1 is C. 12 The curvature of the surface of the second lens 5 near the prescription lens 1 is C. 21In the example of this application, the two curvatures satisfy a proportional relationship: 0.8 <C 12 / C 21 <1.2. This ratio ensures the proper distribution of optical power within the optical module.

[0125] By adjusting the curvature ratio of the first lens 2 and the second lens 5, the propagation path of light in the entire optical module can be optimized, allowing the light to be focused more accurately on the retina, thereby improving image quality.

[0126] The curvature ratio in this example also takes into account the difficulty requirements of curved surface film application.

[0127] Curved surface lamination is a critical process in the manufacturing of optical modules. Excessive curvature differences can increase the difficulty and cost of lamination, and even affect the final product quality.

[0128] By controlling the curvature ratio between 0.8 and 1.2, this application reduces the difficulty of applying film to curved surfaces and improves the manufacturability and yield of the product.

[0129] The first lens 2 and the second lens 5, which satisfy this curvature ratio, help improve the overall performance of the optical module. This includes improving image sharpness, contrast, color reproduction, and reducing distortion and aberrations.

[0130] In addition, the optimized curvature ratio allows the optical module to better adapt to different users' eye shapes and myopia levels, providing a consistent and high-quality visual experience.

[0131] When C 12 / C 21 When the value is small, such as 0.8, it means that the surface curvature of the first lens 2, which is away from the prescription lens 1, is too small compared to the surface curvature of the second lens 5, which is close to the prescription lens 1. This will result in uneven distribution of optical power in the optical module, causing some light rays to fail to focus accurately on the retina, thereby reducing image quality.

[0132] Too small a curvature ratio increases the difficulty and cost of applying film to curved surfaces. More complex processes and technologies may be required during manufacturing to ensure the accuracy and stability of the film application.

[0133] An unreasonable curvature ratio may lead to a decrease in the overall performance of a VR optical system, including a reduction in image sharpness, contrast, and color reproduction, as well as an increase in distortion and aberrations.

[0134] In addition, an overly small curvature ratio may also make it difficult for the optical module to adapt to the eye shapes and myopia degrees of different users, which may cause visual discomfort or poor imaging effects for some users during use.

[0135] When the value of C 12 / C 21 is relatively large, such as greater than 1.2, it means that the surface curvature of the first lens 2 far from the prescription lens 1 is too large relative to the surface curvature of the second lens 5 close to the prescription lens 1. This will cause the optical power to be overly concentrated in a certain area in the optical module, making the light in other areas unable to be effectively utilized. The overly large curvature ratio will also reduce the stability of the optical module. The unreasonable curvature ratio may also lead to an increase in aberration and distortion, which will affect the clarity and accuracy of the image and reduce the user's visual experience.

[0136] Thus, it can be seen that C 12 / C 21 being less than 0.8 or greater than 1.2 may bring problems such as uneven distribution of optical power, increased difficulty in the surface film pasting process, decreased system performance, reduced adaptability, overly concentrated optical power, reduced stability of the optical module, increased aberration and distortion, and increased manufacturing difficulty and cost. Therefore, when designing the optical module, it is necessary to reasonably control the curvature ratio relationship between the first lens 2 and the second lens 5 to ensure the overall performance of the optical module and the user's visual experience.

[0137] In some examples of the present application, the optical module satisfies: 4.5 < f / EPD < 6.0; where f is the effective focal length of the optical module, and EPD is the entrance pupil diameter of the optical module.

[0138] In this example of the present application, the effective focal length f and the entrance pupil diameter EPD of the optical module satisfy the proportional relationship: 4.5 < f / EPD < 6.0. This proportional relationship restricts the relative sizes between the effective focal length f and the entrance pupil diameter EPD, ensuring that they are within a reasonable range.

[0139] By controlling the proportional relationship between the effective focal length f and the entrance pupil diameter EPD of the optical module, the entrance pupil diameter EPD can be appropriately increased. The increased entrance pupil diameter can allow more light to enter the optical module, thereby increasing the luminous flux and brightness of the optical module.

[0140] According to the ratio relationship between f and EPD provided in this example of the present application, the performance degradation caused by the eye ball at different positions in the eye box can be improved. When the user's eye ball moves within the eye box (i.e., the minute movement of the eye ball), the increased entrance pupil diameter helps to maintain the performance stability of the optical system. This can reduce the degradation of the imaging quality caused by the eye ball movement and improve the adaptability of the optical module.

[0141] An increased entrance pupil diameter and a reasonable ratio relationship between the effective focal length contribute to improving the resolution of the optical module. The improvement of resolution means that the optical module can present the details and textures of objects more clearly, enhancing the user's visual experience.

[0142] When the value of f / EPD is less than 4.5, it means that the entrance pupil diameter EPD is too large relative to the effective focal length f. This will cause the optical module to be unable to effectively collect and focus sufficient light, thereby reducing the light flux and brightness of the optical module. An overly small f / EPD value, such as less than 4.5, may lead to an increase in aberrations and distortions of the optical system. These aberrations and distortions will affect the clarity and accuracy of the image, reducing the user's visual experience.

[0143] In a VR headset, the user's eyeballs have a certain range of movement within the eye box. When f / EPD is too small, the optical module may be more sensitive to the minute movements of the eyeballs, resulting in a significant decline in the imaging quality as the eyeballs move.

[0144] When the value of f / EPD is greater than 6, it means that the effective focal length f is too large relative to the entrance pupil diameter EPD. This will cause the FOV of the optical module to be limited, and the user cannot see a sufficiently wide picture. To meet a larger f / EPD ratio, higher-precision manufacturing processes and materials may need to be adopted, which will increase the manufacturing difficulty and cost of the optical module, and is not conducive to the market competitiveness and popularity of the product.

[0145] When using a VR headset for a long time, an overly large f / EPD ratio may cause the user's eyeballs to feel fatigued and uncomfortable. This is because the system may not be able to provide the user with a sufficiently clear and comfortable visual experience, increasing the user's visual burden.

[0146] It can be seen from this that both f / EPD less than 4.5 and greater than 6 may bring problems such as insufficient light collection ability, decreased imaging quality, reduced eye movement tolerance, increased volume and weight of the optical module, limited field of view, increased manufacturing difficulty and cost, as well as eyeball fatigue and discomfort. Therefore, when designing the optical module, it is necessary to reasonably control the ratio relationship of f / EPD to ensure the overall performance of the optical module and the user's visual experience.

[0147] In some examples of the present application, the optical module satisfies: 11.5 < f / BFL < 12.5; where f is the effective focal length of the optical module, and BFL is the distance from the second lens 5 to the image plane.

[0148] According to the ratio range of f / BFL provided by this example of the present application, it ensures the adaptation of the angle of control light to the display screen. This helps to avoid problems such as reflection and glare of the display screen 7 caused by an overly large light incident angle, thereby enhancing the visibility and comfort of the picture.

[0149] By controlling the f / BFL ratio, various aberrations in the optical module can be effectively balanced. These include spherical aberration, chromatic aberration, coma, astigmatism, etc., which, if not effectively controlled, will seriously affect image quality. By adjusting the ratio of focal length f to image plane distance BFL, light can be better focused onto the image plane after passing through the optical module, forming a clear image.

[0150] By controlling the f / BFL ratio, stray light formation can be avoided. Stray light refers to irregular light rays that do not travel along the expected path but are reflected or scattered by internal or external components of the module. These rays interfere with the normal imaging process, leading to problems such as blurry images and reduced contrast. By properly setting the f / BFL ratio, stray light generation can be effectively reduced, ensuring image purity and contrast.

[0151] By adjusting the focal length f and image plane distance BFL while keeping other design parameters constant, the performance of the optical module can be flexibly adjusted within a certain range to meet different application requirements. This helps to achieve miniaturization, weight reduction, and effective cost control of the optical module.

[0152] When the ratio of f to BFL is too small, such as less than 11.5, it means that the effective focal length of the optical module is relatively short, while the distance from the second lens 5 to the image plane is relatively long. This will cause the light emitted from the optical module to strike the display screen 7 at a larger angle, thereby increasing the possibility of reflection and glare on the display screen 7, which will reduce the visibility and comfort of the image.

[0153] A small f-to-BFL ratio cannot balance aberrations in the optical module, which will seriously affect the image quality and cause problems such as blurry images and edge distortion.

[0154] When the f-to-BFL ratio is too small, the internal or external components of the optical module may be more prone to reflection and scattering, resulting in stray light. Increased stray light can interfere with the normal imaging process, reducing image clarity and contrast.

[0155] When the ratio of f to BFL is too large, such as greater than 12.5, it may be necessary to increase the overall length of the optical module in order to meet the requirements of the effective focal length f. This contradicts the current design trend of pursuing miniaturization and lightweighting, and may increase the user's wearing burden and discomfort.

[0156] A large f / BFL value may cause the image plane to shift relative to the ideal position, which will affect the accuracy and sharpness of the image.

[0157] When the value of f / BFL is too large, the light emitted from the light source may not be effectively captured and utilized by the optical module. This will result in an increase in light loss and a decrease in the brightness of the image.

[0158] It can be seen that the selection of the f / BFL ratio has an important impact on the performance and design of the optical module. During the design process, factors such as the light incident angle, aberration control, stray light suppression, and the volume of the optical module need to be comprehensively considered to determine the most suitable range of the f / BFL ratio. 11.5 < f / BFL < 12.5 can achieve the miniaturization and lightweight of the optical module while ensuring the imaging quality.

[0159] In some examples of the present application, referring to Figure 1 , the optical module further includes a display screen 7, the display screen 7 is located on the image source side, the display screen 7 is adjacent to and spaced from the second lens 5 along the optical axis, and the display screen 7 is used to emit light for imaging display.

[0160] The light emitted from the display screen 7 can directly enter the folded optical path. This design reduces the loss of light during transmission and improves the overall light utilization rate. Moreover, the adjacent and spaced arrangement helps to reduce the imaging interference caused by possible stray light or reflected light between the display screen 7 and the second lens 5. This helps to improve the clarity and purity of the image and provides a more realistic visual experience for users.

[0161] The display screen 7 is used to emit light for imaging display.

[0162] In some examples of the present application, referring to Figure 1 , the beam splitter 6 is located on the side of the second lens 5 close to the display screen 7; the reflective polarizing element 3 and the phase retardation plate 4 are located between the first lens 2 and the second lens 5.

[0163] The beam splitter 6 is located on the side of the second lens 5 away from the display screen 7. This position design of the beam splitter 6 helps to more effectively manage the light emitted from the display screen 7. After the light is preliminarily focused and adjusted by the second lens 5, it is then split by the beam splitter 6. Placing the beam splitter 6 at a position away from the display screen 7 can reduce the interference of the light directly emitted by the display screen 7 on the beam splitter 6, reduce the generation of stray light and reflected light, and thus improve the imaging quality.

[0164] The reflective polarization element 3 and the phase retardation plate 4 are located between the first lens 2 and the second lens 5. The reflective polarization element 3 can selectively reflect or transmit light with a specific polarization direction, while the phase retardation plate 4 can adjust the polarization state of the light. Placing these two elements between the first lens 2 and the second lens 5 enables polarization management of the light, thereby improving the contrast and sharpness of the image.

[0165] Among them, the reflective polarization element 3 is a polarization reflective film, the phase delay plate 4 is a quarter-wave plate, and the beam splitter 6 is a semi-transparent and semi-reflective film.

[0166] See some examples in this application. Figure 1 The beam splitter 6 is disposed on the side surface of the second lens 5 near the display screen 7; the reflective polarizing element 3 and the phase delay film 4 form a composite film and are disposed on the side surface of the first lens 2 near the display screen 7.

[0167] Directly mounting key optical components such as the beam splitter 6, the reflective polarizing element 3, and the phase retardation plate 4 onto the surfaces of different lenses offers several advantages, as detailed below:

[0168] Placing optical components directly on the lens surface can significantly reduce the size of the optical module, making VR headsets lighter and more compact. This helps improve user comfort and portability.

[0169] As the primary element for light transmission and focusing, the optical elements on the lens surface allow for more precise control over the path and polarization of light. This helps reduce stray and reflected light, thus improving image quality.

[0170] Placing optical components on the surface of a lens simplifies the assembly process of optical modules, allowing multiple optical components to be installed at once.

[0171] The light propagation path of the optical module provided in this embodiment is as follows:

[0172] See Figure 1Light emitted from the display screen 7 passes through the sixth surface 52 of the second lens 5 and through the beam splitter 6 (semi-transparent and semi-reflective film) on this surface, continuing to the fifth surface 51 of the second lens 5. Subsequently, the light passes through the first lens 2, through the phase retarder 4 on the fourth surface 22 of the first lens 2, and then reaches the reflective polarization element 3. At the reflective polarization element 3, the light is reflected and passes through the phase retarder 4 again, then passes through the fifth surface 51 of the second lens 5 again, reaching the beam splitter 6 on its sixth surface 52 and being reflected back. Afterward, the light passes sequentially through the second lens 5, the phase retarder 4 on the first lens 2, and again reaches the reflective polarization element 3. Finally, the light exits from the reflective polarization element 3, passes through the prescription lens 1, and ultimately enters the human eye 01. In this process, the cooperation and coordinated operation of the lenses and optical elements ensures efficient light transmission and high-quality imaging.

[0173] In some examples of this application, the refractive power DS of the prescription lens 1 is -1.0D to -8.0D, the center thickness T1 of the prescription lens 1 is 1.4mm≤T1≤3.2mm, the refractive index n1 of the prescription lens 1 is 1.595≤n1≤1.74, and the Abbe number of the prescription lens 1 is 32 to 46.

[0174] In this example of the application, the prescription lens 1 (R) x The lens has specific parameter ranges: diopter DS is -1.0D to -8.0D; center thickness T1 is 1.4mm ≤ T1 ≤ 3.2mm; refractive index n1 is 1.595 ≤ n1 ≤ 1.74; and Abbe number is 32 to 46. These parameters collectively define the physical and optical properties of the prescription lens 1, making it suitable for users with different degrees of myopia and providing good visual effects in VR headsets.

[0175] The refractive power range of the prescription lens 1 covers a wide range of people, from low to high myopia, making the VR headset suitable for more users.

[0176] By selecting appropriate refractive index and Abbe number, the prescription lens 1 can reduce optical aberrations such as chromatic aberration and distortion while ensuring clarity, thereby improving the user's visual experience.

[0177] The central thickness of the prescription lens 1 is moderate, which ensures sufficient structural strength while avoiding increased weight and discomfort caused by excessive lens thickness.

[0178] A proper selection of refractive index helps balance lens thickness and image quality. A higher refractive index can reduce lens thickness but may increase dispersion; while a lower refractive index may result in an excessively thick lens. In the example of this application, a good balance between thickness and image quality is achieved by carefully selecting the refractive index range.

[0179] In some examples of this application, the optical module further includes a third lens disposed between the second optical component and the third optical component along the optical axis.

[0180] In this example of the application, the optical module not only includes the previously mentioned prescription lens 1, first lens 2, and second lens 5, but also adds a third lens, which is disposed between the second and third optical components and arranged along the optical axis. The introduction of the third lens can be seen as a supplement and fine-tuning to the original optical module, aiming to further improve image quality, reduce aberrations, and may help to better adapt to users with different degrees of myopia.

[0181] By setting a third lens between the second optical component and the third optical component, the optical power of the entire optical module can be allocated more rationally, so that the light can transition more smoothly when passing through each component, reducing energy loss and aberration.

[0182] The optical module provided in this application embodiment can use 1 to 3 lenses to realize a folded optical path.

[0183] The optical module provided in this application embodiment has a virtual image distance (VID) of 0.5D to 1.5D and an eye relief of 15mm to 30mm.

[0184] The optical module provided in this application is described in detail below through Examples 1 to 3.

[0185] Example 1

[0186] The optical module provided in this embodiment 1 is referred to... Figure 1 It includes a first optical component, a second optical component, a third optical component, and a display screen 7 arranged sequentially along the same optical axis from the human eye side to the image source side;

[0187] The first optical component includes a prescription lens 1 having negative optical power, the prescription lens 1 being used to match the user's vision.

[0188] The second optical component includes a first lens 2, and a reflective polarizing element 3 and a phase retardation plate 4 disposed on the surface of the first lens 2 near the display screen 7 (i.e., the fourth surface 22). The first lens 2 has positive optical power.

[0189] The third optical component includes a second lens 5 and a beam splitter 6 disposed on the surface of the second lens 5 near the display screen 7. The second lens 5 has positive optical power, and the phase retardation plate 4 is located between the beam splitter 6 and the reflective polarizing element 3.

[0190] The surface of the first lens 2 near the prescription lens 1 (i.e., the third surface 21) and the surface of the second lens 5 away from the prescription lens 1 (i.e., the sixth surface 52) are aspherical.

[0191] The prescription lens 1 has a refractive power DS of -2.5D and a refractive index n1 of 1.595. The prescription lens 1 is a spherical lens, and its parameters are shown in Table 1. The prescription lens 1 includes a first surface 11 and a second surface 12. The first surface 11 is located on the side closer to the human eye O1, and the second surface 12 is located on the side farther away from the human eye O1.

[0192] Table 1

[0193] R of the first surface 11 ]]> R of the second surface 12 ]]> center thickness T1 <![CDATA[Refractive index n1]]> Abbe number 283.333mm 129.075mm 1.6mm 1.595 40

[0194] The effective focal length f of the optical module is 30mm.

[0195] For other optical parameters in this embodiment 1, please refer to Table 2.

[0196] Table 2

[0197] # Type Radius Thickness Material Conic A04 A06 A08 A10 A12 A14 1 EVENASPH -1.29E+02 1.60E+00 TRIBRID 0.127 9.14E-12 -1.29E-14 1.54E-17 -9.52E-21 2.72E-24 -2.91E-28 2 STANDARD -2.83E+02 1.29E+01 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 3 EVENASPH 3.80E+02 5.73E+00 K26R_0 0.00E+00 -1.31E-09 2.17E-12 -2.00E-15 8.09E-19 0.00E+00 0.00E+00 4 STANDARD 4.92E+02 6.85E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 5 STANDARD 4.92E+02 7.07E+00 APL5014GH 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

[0198] The optical module of this embodiment 1 has the following optical performance: Figures 2 to 5 As shown: Figure 2 This is a schematic diagram of a dot-matrix diagram. Figure 3 It is an MTF curve. Figure 4 It is a distortion diagram. Figure 5 It is a vertical axis color difference diagram.

[0199] A dot pattern refers to a diffuse pattern formed by numerous rays emanating from a single point. Due to aberrations, these rays intersect the image plane at a point other than a single point, creating a scattered pattern over a certain area. This pattern is used to evaluate the imaging quality of the projection optical module. See also... Figure 2 The optical module provided in this embodiment 1 has a maximum image size of less than 16μm in the dot matrix diagram.

[0200] The MTF curve is a modulation transfer function graph, which characterizes the imaging sharpness of the optical module through the contrast of black and white line pairs. See also Figure 3 The optical module provided in this embodiment has an MTF > 0.1 at 35 lp / mm.

[0201] See Figure 4In the optical module provided in this embodiment 1, the maximum distortion occurs in 1 field of view, and the absolute value is less than 20%.

[0202] Transverse chromatic aberration, also known as magnification chromatic aberration, mainly refers to the difference in focal positions between blue and red light on the image plane when a single polychromatic principal ray from the object side is emitted as multiple rays due to dispersion in the refraction system. (See also...) Figure 5 The optical module provided in this embodiment 1 has a maximum color difference value of less than 110μm.

[0203] Example 2

[0204] The optical module provided in this embodiment 2 is described in [reference]. Figure 6 It includes a first optical component, a second optical component, a third optical component, and a display screen 7 arranged sequentially along the same optical axis from the human eye side to the image source side;

[0205] The first optical component includes a prescription lens 1, which has negative optical power;

[0206] The second optical component includes a first lens 2, and a reflective polarizing element 3 and a phase retardation plate 4 disposed on the surface of the first lens 2 near the display screen 7 (i.e., the fourth surface 22). The first lens 2 has positive optical power.

[0207] The third optical component includes a second lens 5 and a beam splitter 6 disposed on the surface of the second lens 5 near the display screen 7. The second lens 5 has positive optical power, and the phase retardation plate 4 is located between the beam splitter 6 and the reflective polarizing element 3.

[0208] The surface of the first lens 2 near the prescription lens 1 (i.e., the third surface 21) and the surface of the second lens 5 away from the prescription lens 1 (i.e., the sixth surface 52) are aspherical.

[0209] The prescription lens 1 has a refractive power DS of -8.0D and a refractive index n1 of 1.595. The prescription lens 1 is a spherical lens, and its parameters are shown in Table 3. The prescription lens 1 includes a first surface 11 and a second surface 12. The first surface 11 is located on the side closer to the human eye O1, and the second surface 12 is located on the side farther away from the human eye O1.

[0210] Table 3

[0211] <![CDATA[Radius of the first surface 11 > <![CDATA[Radius of the second surface 12 > <![CDATA[Central thickness T1]]> <![CDATA[Refractive index n1]]> Abbe number 72.76mm 558.3mm 1.6mm 1.595 440

[0212] The effective focal length f of the optical module is 30mm.

[0213] For other optical parameters in this embodiment 2, please refer to Table 4.

[0214] Table 4

[0215] # Type Radius Thickness Material Conic A04 A06 A08 A10 A12 A14 1 EVENASPH -5.583E+02 1.60 TRIBRID 0.172 -1.1E-8 1.48E-11 -2.08E-14 -1.53E-17 -6.5E-21 1.45E-24 2 STANDARD -7.276E+02 1.29E+01 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 3 EVENASPH 3.80E+02 5.73E+00 K26R_0 0.00E+00 -1.31E-09 2.17E-12 -2.00E-15 8.09E-19 0.00E+00 0.00E+00 4 STANDARD 4.92E+02 6.85E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 5 STANDARD 4.92E+02 7.07E+00 APL5014GH 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

[0216] The optical module provided in this embodiment 2 has the following optical performance: Figures 7 to 10 As shown: Figure 7 This is a schematic diagram of a dot-matrix diagram. Figure 8 It is an MTF curve. Figure 9 It is a distortion diagram. Figure 10 It is a vertical axis color difference diagram.

[0217] A dot pattern refers to a diffuse pattern formed by numerous rays emanating from a single point. Due to aberrations, these rays intersect the image plane at a point other than a single point, creating a scattered pattern over a certain area. This pattern is used to evaluate the imaging quality of the projection optical module. See also... Figure 7 The optical module provided in this embodiment 2 has a maximum image size of less than 20μm in the dot matrix diagram.

[0218] The MTF curve is a modulation transfer function graph, which characterizes the imaging sharpness of the optical module through the contrast of black and white line pairs. See also Figure 8 The optical module provided in this embodiment 2 has an MTF of >0.15 at 21 lp / mm.

[0219] See Figure 9 In the optical module provided in this embodiment 2, the maximum distortion occurs in 1 field of view, and the absolute value is less than 20%.

[0220] Transverse chromatic aberration, also known as magnification chromatic aberration, mainly refers to the difference in focal positions between blue and red light on the image plane when a single polychromatic principal ray from the object side is emitted as multiple rays due to dispersion in the refraction system. (See also...) Figure 10 The optical module provided in this embodiment 2 has a maximum color difference value of less than 110μm.

[0221] According to another embodiment of this application, a smart head-mounted device is provided, including a housing and an optical module as described above.

[0222] 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.

[0223] 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 optical module, characterized in that, It includes a first optical component, a second optical component, and a third optical component arranged in sequence along the same optical axis from the human eye side to the image source side; The first optical component includes a prescription lens (1), the prescription lens (1) has a negative optical power, and the prescription lens (1) is used to match the visual acuity of the user; The second optical component includes a first lens (2), a reflective polarization element (3), and a phase retarder (4) disposed on at least one side of the first lens (2), and the first lens (2) has a positive optical power; The third optical component includes a second lens (5) and a beam splitter element (6) disposed on one side of the second lens (5), the second lens (5) has a positive optical power, and the phase retarder (4) is located between the beam splitter element (6) and the reflective polarization element (3); The distance along the optical axis between the surface of the prescription lens (1) away from the first lens (2) and the surface of the first lens (2) close to the prescription lens (1) is TD, the central thickness of the prescription lens (1) is CT1, and 8.5 < TD / CT1 < 12.

5.

2. The optical module according to claim 1, characterized in that, The relationship between the central thickness CT1 of the prescription lens (1) and the central thickness CT2 of the first lens (2) satisfies: 1.7 < |(CT1 + CT2) / (CT1 - CT2)| < 2.

5.

3. The optical module according to claim 2, characterized in that, The relationship between the central thickness CT2 of the first lens (2) and the central thickness CT3 of the second lens (5) satisfies: 9.5 < |(CT2 + CT3) / (CT2 - CT3)| < 10.

5.

4. The optical module according to claim 1, characterized in that, The optical module satisfies: 1.0 < (L1 + L2) / (L1 - L2) < 1.5; where L1 is the effective focal length of the first lens (2), and L2 is the effective focal length of the second lens (5).

5. The optical module according to claim 1, characterized in that, The surface of the first lens (2) close to the prescription lens (1) and the surface of the second lens (5) away from the prescription lens (1) are aspherical surfaces.

6. The optical module according to claim 1, characterized in that, The curvature of the surface of the first lens (2) away from the prescription lens (1) is C. 12 The curvature of the surface of the second lens (5) near the prescription lens (1) is C. 21 0.8 <C 12 / C 21 <1.

2.

7. The optical module according to claim 1, characterized in that, The optical module satisfies: 4.5 < f / EPD < 6.0; where f is the effective focal length of the optical module, and EPD is the entrance pupil diameter of the optical module.

8. The optical module according to claim 7, characterized in that, The optical module satisfies: 11.5 < f / BFL < 12.5; where f is the effective focal length of the optical module, and BFL is the distance from the second lens (5) to the image plane.

9. The optical module according to any one of claims 1-8, characterized in that, The optical module further includes a display screen (7), the display screen (7) is located on the image source side, the display screen (7) is adjacent to and spaced from the second lens (5) along the optical axis, and the display screen (7) is used to emit light for imaging display.

10. The optical module according to claim 9, characterized in that, The beam splitter element (6) is located on the side of the second lens (5) close to the display screen (7); The reflective polarization element (3) and the phase retarder (4) are located between the first lens (2) and the second lens (5).

11. The optical module according to claim 10, characterized in that, The beam splitter element (6) is disposed on the surface of the second lens (5) close to the display screen (7); The reflective polarization element (3) and the phase retarder (4) form a composite film material and are disposed on the surface of the first lens (2) close to the display screen (7).

12. The optical module according to claim 1, characterized in that, The refractive power DS of the prescription lens (1) is -1.0D to -8.0D, and the center thickness T1 of the prescription lens (1) is 1.4mm≤T1≤3.2mm; The refractive index n1 of the prescription lens (1) is 1.595≤n1≤1.74, and the Abbe number of the prescription lens (1) is 32~46.

13. The optical module according to claim 1, characterized in that, The optical module further includes a third lens, which is disposed between the second optical component and the third optical component along the optical axis.

14. A smart head-mounted device, characterized in that, include: shell; and The optical module as described in any one of claims 1-13.

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