Optical module and intelligent head-mounted device

Abstract

The embodiment of the invention provides an optical module and intelligent head-mounted equipment. 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 human eye side to the image source side. The first optical assembly comprises a prescription lens, and the prescription lens has negative focal power; the second optical assembly comprises a first lens, and a reflective polarization element and a phase delay sheet which are arranged on at least one side of the first lens, and the first lens has positive focal power; the third optical assembly comprises a second lens and a light splitting element arranged on one side of the second lens, the second lens has positive focal power, and the phase delay piece is located between the light splitting element and the reflection polarization element; the distance between the surface, away from the first lens, of the prescription lens and the surface, close to the prescription lens, of the first lens in the optical axis direction is TD, and the center thickness of the prescription lens is CT1, 8.5 lt; tD / CT 1lt; 12.5, 12.5.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical display technology. More specifically, the embodiments of the present application relate to an optical module and a smart head-mounted device. Background Art

[0002] Currently, prescription lenses (R x The design of prescription lenses is mainly used to correct myopia, astigmatism and other vision problems. However, in VR head-mounted display devices, prescription lenses (R x The prescription lens (R x The focus of the prescription lens (R lens) is mainly on vision correction function, without considering its impact on the optical performance of the entire module after being added to the optical module. x When a VR lens is introduced into an already designed optical module such as a VR module, it may cause a decrease in performance indicators such as distortion and clarity, thus affecting the user's visual experience. Summary of the invention

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

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

[0005] The first optical component includes a prescription lens, the prescription lens has a negative optical power, and the prescription lens is 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 focal length, and the phase delay plate is located between the beam splitter and the reflective polarizing element;

[0008] 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 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: 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 from the second lens along the optical axis. The display screen is used to emit light for imaging and 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 32-46.

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

[0024] In a second aspect, the present application provides a smart head-mounted device. The smart head-mounted device includes:

[0025] casing; and

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

[0027] The beneficial effects of this application are:

[0028] The optical module provided in the embodiment of the present application is an optical module with a diopter adjustment function. The optical module can reduce the problem of a decrease in the performance index of the optical module due to the addition of prescription lenses while ensuring the vision correction function, and can improve the overall imaging quality. In addition, the optical module provided in the embodiment of the present application has a compact structure and high integration, and is suitable for various smart head-mounted devices.

[0029] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0031] Figure 1 One of the structures and optical path diagrams of the optical module provided in the embodiment of the present application;

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

[0033] Figure 3 for Figure 1 MTF diagram of the optical module shown;

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

[0035] Figure 5 for Figure 1 A vertical axis chromatic aberration diagram of the optical module shown;

[0036] Figure 6The second structure and optical path diagram of the optical module provided in the embodiment of the present application;

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

[0038] Figure 8 for Figure 2 MTF diagram of the optical module shown;

[0039] Fig. 9 for Figure 2 Field curvature distortion diagram of the optical module shown;

[0040] Fig.10 for Figure 2 A diagram of vertical axis chromatic aberration of the optical module is shown.

[0041] Description of reference numerals:

[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 retarder;

[0045] 5. second lens; 51. fifth surface; 52. sixth surface;

[0046] 6. Spectral element; 7. Display screen;

[0047] 01. Human eye. DETAILED DESCRIPTION

[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 of components and steps, numerical expressions and numerical values ​​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 in nature and is in no way intended to limit the present application, its application, or uses.

[0050] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0051] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0052] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0053] The optical module and the smart head-mounted device provided in the embodiments of the present application are described in detail below in conjunction with the accompanying drawings.

[0054] According to one embodiment of the present application, an optical module is provided. Figure 1 , the optical module 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 focal length, and the prescription lens 1 is 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 delay plate 4 arranged on at least one side of the first lens 2, the first lens 2 has a positive optical focal length; the third optical component includes a second lens 5 and a beam splitter 6 arranged on one side of the second lens 5, the second lens 5 has a positive optical focal length, and the phase delay plate 4 is located between the beam splitter 6 and the reflective polarizing element 3; the distance 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 along the optical axis direction is TD, and the center thickness of the prescription lens 1 is CT1,8.5 <TD / CT1<12.5。

[0055] The embodiment of the present application provides an optical module for a VR smart head mounted display device, wherein the optical module particularly comprises a prescription lens 1 (R x The optical module is described in detail, along with the optical architecture and focal length relationships between some components.

[0056] See also Figure 1 The optical module provided in the embodiment of the present application comprises 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; wherein the first optical component comprises a prescription lens 1 (R x The prescription lens 1 has a negative optical power and can be used to match the user's vision, that is, to achieve a vision (such as myopia) adjustment function.

[0057] Optionally, the diopter DS of the prescription lens 1 is -1.0 D to -8.0 D. The prescription lens 1 can be adapted to most myopic users within this diopter range.

[0058] In the optical module provided in the embodiment of the present application, the second optical component is designed to include a first lens 2 with positive optical power, a reflective polarizing element 3 and a phase retarder 4. These optical elements can act together on the polarization state and phase of light to achieve a specific optical effect.

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

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

[0061] In the optical module provided in the embodiment of the present application, 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 retarder 4 can be used to change the polarization state of light, such as to convert linearly polarized light into circularly polarized light, or to convert circularly polarized light into linearly polarized light.

[0063] The phase retarder 4 used in the present application is, for example, a quarter-wave plate, which is located between the beam splitter element 6 and the reflective polarization element 3 and ensures that the light can be reflected or transmitted in the subsequent path by adjusting the phase of the light.

[0064] In the optical module provided in the embodiment of the present application, 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 into different paths, and can be used to realize image projection or display.

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

[0066] The light splitting element 6 in the present application is, for example, a semi-transparent and semi-reflective film, which can allow a portion of light to pass through and another portion of light to reflect.

[0067] It should be noted that the reflectivity and transmittance of the light splitting element 6 can be flexibly adjusted according to specific needs, and this is not limited in the embodiments of the present application.

[0068] In the optical system of the embodiment of the present application, the phase retarder 4 is located between the beam splitter 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. The folded optical path is used in combination with the prescription lens 1 introduced near the human eye side to provide a good visual experience and can adapt to the vision of different users. 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 matching with the optical module under 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 value of TD / CT1 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 cause the distortion introduced by the prescription lens 1 in the optical module to increase. Distortion is a common optical problem in VR devices, which will cause image distortion and reduce the user's visual experience.

[0076] A smaller value of TD / CT1 may also make it difficult for the prescription lens 1 to maintain good matching with the optical module at different myopia degrees, which may cause the user to feel uncomfortable when using the optical module for visual experience, or the image quality may vary depending on the myopia degree.

[0077] If the distance between the prescription lens 1 and the first lens is too close, it may affect the reasonable distribution of the optical power in the optical module. Reasonable distribution of optical power is one of the keys to ensure the imaging quality of VR equipment, and unreasonable distribution may lead to a decrease in imaging quality.

[0078] When the value of TD / CT1 is too large, it means that the distance between the prescription lens 1 and the first lens 2 is relatively far, which may increase the overall volume of the optical module. The increased system volume may be inconvenient for users to wear and use, reducing the portability of the device. In addition, the distance between the prescription lens 1 and the first lens 2 is too far, which may affect the propagation path of light in the optical module, which may cause more loss and distortion of light during propagation, thereby reducing the overall performance of the optical module.

[0079] It can be seen that when the TD / CT1 value is between 8.5 and 12.5, it can achieve multiple technical effects such as reducing the impact of distortion, improving adaptability, optimizing optical power distribution, and maintaining a moderate module volume. If the ratio is less than 8.5 or greater than 12.5, it may cause problems such as increased distortion, poor adaptability, unreasonable optical power distribution, increased module volume, and decreased performance. Therefore, when designing and manufacturing optical modules, the TD / CT1 ratio must be controlled to ensure the overall performance of the optical module and user experience.

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

[0081] That is to say, the optical module provided in the embodiment of the present application is an optical module with a diopter adjustment function, which can reduce the problem of a decrease in the performance index of the optical module due to the addition of prescription lenses while ensuring the vision correction function, and can improve the overall imaging quality. In addition, the optical module provided in the embodiment of the present application has a compact structure and high integration, and is suitable for various smart head-mounted devices.

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

[0083] According to this example of the present 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 and CT2, the refraction angle and path of light passing through different lenses can be adjusted, thereby effectively reducing the distortion and aberration during imaging. This is especially important for systems that require high-precision imaging.

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

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

[0087] On the basis of satisfying 1.7<|(CT1+CT2) / (CT1-CT2)|<2.5, when the center thickness of the first lens 2 and the second lens 5 is designed to satisfy 9.5<|(CT2+CT3) / (CT2-CT3)|<10.5, by adjusting the ratio of CT2 and CT3, the optical performance of the optical module can be further optimized, especially for correcting higher-level aberrations.

[0088] 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 effects within a larger field of view, effectively reducing 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 equipment.

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

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

[0093] If the three lenses in the optical module cannot meet the conditions constrained by the above two examples, a series of adverse consequences will occur. Specifically, this will first cause problems in the control of distortion and aberration, making it difficult to guarantee the imaging quality. At the same time, in order to meet basic optical performance, it may be necessary to increase the volume of the optical module, which is contrary to the current design trend of pursuing miniaturization and lightweight. In addition, the difficulty of processing and manufacturing the lenses will also increase. It can be seen that ensuring that the thickness relationship of the three lenses meets the requirements of the above examples is crucial to maintaining the overall performance of the optical module, controlling the volume and reducing the difficulty of manufacturing.

[0094] In some examples of the present application, the optical module satisfies: 1.0<(L1+L2) / (L1-L2)<1.5; wherein 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 embodiment of the present 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 reasonably distribute the focal power and optimize the performance of the optical module.

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

[0097] Numerator (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] Denominator (L1-L2): represents the difference between the effective focal lengths of the two lenses, reflecting the distribution or difference of the focal lengths of different parts of the optical module.

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

[0100] This focal length relationship in the present application helps to reasonably distribute the optical focal length, so that the optical module maintains a balanced state in terms of the overall focal length. By adjusting the focal length ratio of L1 and L2, the refraction and focusing effect of light when passing through different lenses can be optimized, thereby improving the imaging quality.

[0101] Reasonable setting of focal length relationship helps to reduce aberration and distortion. Aberration and distortion are common problems in optical imaging systems, which will affect the clarity and accuracy of imaging. By adjusting the focal length ratio, the light can be more evenly focused on the image plane when passing through the lens, thereby reducing the occurrence of aberration and distortion.

[0102] For VR headsets, the quality of imaging directly affects the user's visual experience. By optimizing the focal length relationship of the optical module, the imaging quality can be improved, allowing users to obtain clearer and more realistic visual effects when using VR headsets.

[0103] In addition, the reasonable setting of the focal length relationship also helps to achieve the compactness and lightness of the optical module. Under the premise of maintaining a certain imaging quality, by optimizing the focal length ratio, the size and weight of the lens 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, which may lead to unreasonable distribution of optical power between the two elements, which may cause some parts of the optical module to be over-corrected or under-corrected, thereby affecting the overall imaging quality.

[0105] Reasonable optical power distribution and optical path refraction are the 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 cause the VR device to be too large and inconvenient to wear and use.

[0106] Small focal length differences may cause light to be more susceptible to interference when propagating in the optical module, such as stray light, aberrations, etc. These interferences may cause the performance of the optical module to deteriorate, such as reduced clarity, increased distortion, etc.

[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 and other parts to be undercorrected, affecting the overall imaging effect. A large difference in focal length may cause large aberrations and distortions when light propagates in the module, which may impair the image quality, such as blurred edges and color distortion.

[0108] It can be seen that when the ratio (L1+L2) / (L1-L2) is between 1.0 and 1.5, the optical power can be reasonably distributed, the length of the optical module can be compressed, and good imaging quality can be maintained. If the ratio is less than 1.0 or greater than 1.5, it may lead to unreasonable optical power distribution, difficulty in compressing the length of the optical module, performance degradation, and increased difficulty in processing and manufacturing.

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

[0110] The optical module provided in the embodiment of the present application 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] In some examples of this application, see Figure 1 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.

[0112] See also 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 to see Figure 1 The surface of the first lens 2 close to the prescription lens 1, that is, the third surface 21, is an aspheric surface. The surface of the second lens 5 away from the prescription lens 1, that is, the sixth surface 52, is also an aspheric surface. This design helps to improve the field curvature aberration and correct the astigmatism aberration.

[0114] Aspherical lenses have better curvature radius 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 adopting an aspherical design, the present application can significantly reduce field curvature aberration, making the image flatter and clearer throughout the field of view.

[0117] In addition to field curvature aberration, astigmatism aberration is also an important issue that needs to be paid attention to in optical modules. Astigmatism aberration will cause different degrees of blur and distortion of the image in different directions of the field of view. In this application, the use of aspherical lenses helps to correct astigmatism aberration and improve the clarity and sharpness of the image.

[0118] Aspheric design can also help optimize the distribution of optical power in the optical module. By adjusting the radius of curvature and other parameters of the aspheric lens, it is possible to ensure that the propagation path of light in the optical module is more reasonable and reduce the loss and distortion of light during the propagation process. This helps to improve the overall performance of the optical module, including contrast, resolution, and color reproduction.

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

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

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

[0122] In some examples of this application, see 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 close to the prescription lens 1 is C 21 , 0.8 <C 12 / C 21 <1.2.

[0123] The first lens 2 is located away from a surface of the prescription lens 1 , namely, a fourth surface 22 , and the second lens 5 is located close to a surface of the prescription lens 1 , namely, a 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 close to the prescription lens 1 is C 21In the example of this application, the two curvatures satisfy the proportional relationship: 0.8 <C 12 / C 21 <1.2. This ratio ensures the reasonable distribution of optical power in the optical module.

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

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

[0127] In the manufacturing process of optical modules, curved surface film lamination is a key process step. Too large a curvature difference may increase the difficulty and cost of film lamination, and even affect the final product quality.

[0128] By controlling the curvature ratio between 0.8 and 1.2, the present application reduces the difficulty of curved surface film application and improves the manufacturability and yield rate of the product.

[0129] The first lens 2 and the second lens 5 satisfying the curvature ratio relationship are helpful to improve the overall performance of the optical module, including improving the clarity, contrast, color reproduction of the image, and reducing distortion and aberration.

[0130] In addition, the optimized curvature ratio enables the optical module to better adapt to the eye shape and myopia degree of different users, providing a consistent and high-quality visual experience.

[0131] When C 12 / C 21 When the value of is small, such as 0.8, it means that the surface curvature of the first lens 2 away from the prescription lens 1 is too small relative to the surface curvature of the second lens 5 close to the prescription lens 1. This will lead to uneven distribution of optical power in the optical module, so that some light cannot be accurately focused on the retina, thereby reducing the image quality.

[0132] Too small a curvature ratio will increase the difficulty and cost of applying the film to the curved surface. During the manufacturing process, more complex processes and technologies may be required to ensure the accuracy and stability of the film.

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

[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 away 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 Both being less than 0.8 and greater than 1.2 may bring problems such as uneven distribution of optical power, increased difficulty in the curved surface film - sticking process, decreased system performance, reduced adaptability, over - concentration of optical power, reduced stability of the optical module, increased aberration and distortion, as well as 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 magnitudes 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 stable performance 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 of 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 value of f / EPD, 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 eyeball has a certain range of movement within the eye box. When f / EPD is too small, the optical module may be more sensitive to the slight movement of the eyeball, resulting in a significant decrease in the imaging quality as the eyeball moves.

[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 be required, 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, and 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 angular adaptation of controlling light and the display screen. This helps to avoid problems such as reflection and glare of the display screen 7 caused by too large an incident angle of light, thereby enhancing the visibility and comfort of the picture.

[0149] By controlling the ratio of f / BFL, various aberrations in the optical module can be effectively balanced. This includes spherical aberration, chromatic aberration, coma, astigmatism, etc. If these aberrations are not effectively controlled, they will seriously affect the image quality. By adjusting the ratio of focal length f and image plane distance BFL, the light can be better focused on the image plane after passing through the optical module to form a clear image.

[0150] By controlling the f / BFL ratio, the formation of stray light can also be avoided. Stray light refers to irregular light that is not propagated along the expected path but is reflected and scattered by internal or external components of the module. These lights will interfere with the normal imaging process, causing problems such as blurred images and reduced contrast. By setting the f / BFL ratio reasonably, the generation of stray light can be effectively reduced to ensure the purity and contrast of the imaging.

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

[0153] A smaller f / BFL ratio cannot balance the aberrations in the optical module, which will seriously affect the imaging quality and cause problems such as blurred images and edge distortion.

[0154] When the ratio of f to BFL is too small, the internal or external components of the optical module may be more likely to produce reflection and scattering, thereby forming stray light. The increase of stray light will interfere with the normal imaging process and reduce the purity and contrast of the picture.

[0155] When the ratio of f to BFL is too large, such as greater than 12.5, the overall length of the optical module may need to be increased in order to meet the requirements of the effective focal length f. This is contrary to the current design trend of pursuing miniaturization and lightweight, and may increase the wearing burden and discomfort of users.

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

[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 appropriate range of the f / BFL ratio. 11.5 < f / BFL < 12.5 can achieve the miniaturization and light weight 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 the user.

[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 splitting 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 retardation plate 4 are located between the first lens 2 and the second lens 5.

[0163] The beam splitting element 6 is located on the side of the second lens 5 away from the display screen 7. This position design of the beam splitting element 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 splitting element 6. Placing the beam splitting element 6 at a position away from the display screen 7 can reduce the interference of the light directly emitted from the display screen 7 on the beam splitting element 6, reduce the generation of stray light and reflected light, and thus improve the imaging quality.

[0164] The reflective polarizing element 3 and the phase retarder 4 are located between the first lens 2 and the second lens 5. The reflective polarizing element 3 can selectively reflect or transmit light of a specific polarization direction, while the phase retarder 4 can adjust the polarization state of the light. Placing these two elements between the first lens 2 and the second lens 5 can achieve polarization management of the light, thereby improving the contrast and clarity of the imaging.

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

[0166] In some examples of this application, see Figure 1 The spectroscopic element 6 is arranged on a side surface of the second lens 5 close to the display screen 7; the reflective polarizing element 3 and the phase delay plate 4 form a composite film material and are arranged on a side surface of the first lens 2 close to the display screen 7.

[0167] Directly arranging the key optical elements such as the beam splitter element 6, the reflective polarization element 3 and the phase delay plate 4 on the surfaces of different lenses has many advantages, as follows:

[0168] Placing optical elements directly on the lens surface can significantly reduce the volume of the optical module, making the VR headset lighter and more compact. This helps improve the user's wearing comfort and portability.

[0169] The lens is the main transmission and focusing element of light, and the optical elements arranged on its surface can more accurately control the path and polarization state of light. This helps to reduce the generation of stray light and reflected light and improve imaging quality.

[0170] Placing the optical element on the surface of the lens can simplify the assembly process of the optical module and enable multiple optical elements to be installed at one time.

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

[0172] See also Figure 1, the light emitted from the display screen 7 passes through the sixth surface 52 of the second lens 5, and penetrates the beam splitter 6 (semi-transparent and semi-reflective film) on this surface, and continues to reach the fifth surface 51 of the second lens 5; then, the light passes through the first lens 2, passes through the phase delay plate 4 on the fourth surface 22 of the first lens 2, and then reaches the reflective polarizing element 3, where the light is reflected and passes through the phase delay plate 4 again, and then passes through the fifth surface 51 of the second lens 5 again, reaches the beam splitter 6 on its sixth surface 52 and is reflected back; then, the light passes through the second lens 5 and the phase delay plate 4 on the first lens 2 in turn, and reaches the reflective polarizing element 3 again; finally, the light is emitted from the reflective polarizing element 3, passes through the prescription lens 1, and finally enters the human eye 01. In this process, the coordination and cooperation of each lens and optical element ensures the effective transmission of light and high-quality imaging.

[0173] In some examples of the present application, the refractive power DS of the prescription lens 1 is: -1.0D~-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 32~46.

[0174] In this example of the present application, the prescription lens 1 (R x The prescription lens has a specific parameter range: the diopter DS is -1.0D to -8.0D; the center thickness T1 is 1.4mm≤T1≤3.2mm; the refractive index n1 is 1.595≤n1≤1.74; and the Abbe number is 32 to 46. These parameters together define the physical and optical properties of the prescription lens 1, so that it can be suitable for users with different degrees of myopia and provide good visual effects in VR head-mounted display devices.

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

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

[0177] The prescription lens 1 has a moderate center thickness, which not only ensures sufficient structural strength but also avoids weight increase and wearing discomfort caused by excessive thickness of the lens.

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

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

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

[0181] By arranging a third lens between the second optical component and the third optical component, the optical focal length of the entire optical module can be more reasonably distributed, so that light can transition more smoothly when passing through each component, reducing energy loss and aberration generation.

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

[0183] The optical module provided in the embodiment of the present application 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 by the present application is described in detail below through Examples 1 to 3.

[0185] Example 1

[0186] The optical module provided in this embodiment 1 is shown in FIG. Figure 1 , comprising a first optical component, a second optical component, a third optical component and a display screen 7 which are arranged in sequence 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, the prescription lens 1 has a negative optical power, and the prescription lens 1 is 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 retarder 4 arranged on a surface of the first lens 2 close to the display screen 7 (i.e., the fourth surface 22), wherein 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 a surface of the second lens 5 close to the display screen 7, the second lens 5 has positive optical power, and the phase retarder 4 is located between the beam splitter 6 and the reflective polarizing element 3;

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

[0191] The refractive power DS of the prescription lens 1 is -2.5D, the refractive index n1 of the prescription lens 1 is 1.595, and the prescription lens 1 is a spherical lens. Please refer to Table 1 for its parameters; the prescription lens 1 includes a first surface 11 and a second surface 12, the first surface 11 is located on the side close to the human eye 01, and the second surface 12 is located on the side away from the human eye 01.

[0192] Table 1

[0193] <![CDATA[R of the first surface 11 > <![CDATA[R of the second surface 12 > <![CDATA[Central 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 30 mm.

[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 properties: Figures 2 to 5 As shown: Figure 2 is a schematic diagram of the point diagram. Figure 3 is the MTF curve graph, Figure 4 is the field curvature distortion diagram, Figure 5 This is the vertical axis chromatic aberration diagram.

[0199] The spot diagram refers to a diffuse diagram formed by the intersection of many light rays emitted from one point and the image plane after passing through the optical module. Due to aberration, the intersection points of the light rays with the image plane are no longer concentrated at the same point, but are spread over a certain range. It is used to evaluate the imaging quality of the projection optical module. Figure 2 In the optical module provided in the first embodiment, the maximum value of the image point in the point diagram is less than 16 μm.

[0200] The MTF curve is a modulation transfer function graph that characterizes the imaging clarity of an optical module through the contrast of black and white line pairs. Figure 3 The optical module provided in this embodiment 1 has an MTF of >0.1 at 35lp / mm.

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

[0202] Vertical axis chromatic aberration is also called magnification chromatic aberration. It mainly refers to the difference between the focal positions of blue light and red light on the image plane. Figure 5 , the optical module provided in this embodiment 1 has a maximum chromatic aberration value less than 110 μm.

[0203] Example 2

[0204] The optical module provided in this embodiment 2 is shown in FIG. Figure 6 , comprising a first optical component, a second optical component, a third optical component and a display screen 7 which are arranged in sequence 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, wherein the prescription lens 1 has a negative optical power;

[0206] The second optical component includes a first lens 2, and a reflective polarizing element 3 and a phase retarder 4 arranged on a surface of the first lens 2 close to the display screen 7 (i.e., the fourth surface 22), wherein 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 a surface of the second lens 5 close to the display screen 7, the second lens 5 has positive optical power, and the phase retarder 4 is located between the beam splitter 6 and the reflective polarizing element 3;

[0208] The surface of the first lens 2 close to the prescription lens 1 (ie, the third surface 21 ) and the surface of the second lens 5 far from the prescription lens 1 (ie, the sixth surface 52 ) are aspherical surfaces.

[0209] The refractive power DS of the prescription lens 1 is -8.0D, the refractive index n1 of the prescription lens 1 is 1.595, and the prescription lens 1 is a spherical lens. Please refer to Table 3 for its parameters; the prescription lens 1 includes a first surface 11 and a second surface 12, the first surface 11 is located on the side close to the human eye 01, and the second surface 12 is located on the side away from the human eye 01.

[0210] Table 3

[0211] <![CDATA[Radius of the first surface 11 > <![CDATA[R 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 30 mm.

[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 performance of the optical module provided in this embodiment 2 can be as follows: Figures 7 to 10 As shown: Figure 7 is a schematic diagram of the point diagram. Figure 8 is the MTF curve graph, Fig. 9 is the field curvature distortion diagram, Fig.10 This is the vertical axis chromatic aberration diagram.

[0217] The spot diagram refers to a diffuse diagram formed by the intersection of many light rays emitted from one point and the image plane after passing through the optical module. Due to aberration, the intersection points of the light rays with the image plane are no longer concentrated at the same point, but are spread over a certain range. It is used to evaluate the imaging quality of the projection optical module. Figure 7 In the optical module provided in the second embodiment, the maximum value of the image point in the point diagram is less than 20 μm.

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

[0219] See also Fig. 9 In the optical module provided in the second embodiment, the maximum distortion occurs in one field of view, and the absolute value is less than 20%.

[0220] Vertical axis chromatic aberration is also called magnification chromatic aberration. It mainly refers to the difference between the focal positions of blue light and red light on the image plane. Fig.10 , the optical module provided in this embodiment 2 has a maximum chromatic aberration value less than 110 μm.

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

[0222] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0223] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. An optical module, characterized in that: It includes a first optical component, a second optical component, and a third optical component that are sequentially arranged 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) far 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 central thickness CT1 of the prescription lens (1) and the central thickness CT2 of the first lens (2) satisfy: 1.7 < |(CT1 + CT2) / (CT1 - CT2)| < 2.

5.

3. The optical module according to claim 2, characterized in that: The central thickness CT2 of the first lens (2) and the central thickness CT3 of the second lens (5) satisfy: 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) far 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) close to 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 to 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 diopter 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, and the third lens 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 An optical module as claimed in any one of claims 1 to 13.

Images