Optical modules and near-eye display devices

Abstract

An embodiment of the present application provides an optical module and a near-eye display device; the optical module is used for an XR optical device, and the optical module includes adjacent and spaced-apart cemented prisms and a lens; the cemented prism includes a first prism, a polarized reflective element, and a second prism arranged in sequence, the lens is located on a side of the second prism away from the first prism, and a phase retarder is provided between the lens and the second prism; the lens includes a fifth surface and a sixth surface, the sixth surface faces away from the cemented prism, and the sixth surface is a partially reflective surface; the cemented prism and the lens include at least two curved surfaces; the optical module satisfies 7.4≤|EFL 24 / EFL 56 |≤9.2; EFL 24 is the effective focal length of the cemented prism, EFL 56 It is the effective focal length of light incident from the fifth surface, reflected by the sixth surface, and then emitted from the fifth surface.

Description

Technical Field

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

[0002] With the rise of the metaverse, XR technology has rapidly developed, encompassing AR, VR, and MR technologies. Near-eye display systems, as a core component of XR technology, have a direct impact on user experience. However, existing near-eye display devices still face challenges in optical module design, such as excessive size, poor image quality, and a limited field of view. Therefore, designing an optical module that is compact, offers high image quality, and a wide field of view has become a pressing technical challenge. Summary of the Invention

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

[0004] In a first aspect, the present application provides an optical module. The optical module is used in an XR optical device and includes adjacent and spaced cemented prisms and a lens;

[0005] The cemented prism includes a first prism, a polarized reflective element, and a second prism arranged in sequence, the lens is located on a side of the second prism away from the first prism, and a phase retarder is provided between the lens and the second prism;

[0006] The lens includes a fifth surface and a sixth surface, the sixth surface faces away from the cemented prism, and the sixth surface is a partially reflective surface;

[0007] The cemented prism and the lens include at least two curved surfaces;

[0008] The optical module satisfies: 7.4≤|EFL 24 / EFL 56 |≤9.2; among which, EFL 24 is the effective focal length of the cemented prism, EFL 56 It is the effective focal length of light incident from the fifth surface, reflected by the sixth surface, and then emitted from the fifth surface.

[0009] Optionally, the second prism includes a fourth surface, and an air gap is provided between the fourth surface and the fifth surface.

[0010] Optionally, a light splitting element is provided on the sixth surface;

[0011] The phase retarder is disposed on the fifth surface;

[0012] The bonding surface between the first prism and the second prism is a third surface, and the polarized reflection element is disposed on the third surface.

[0013] Optionally, the first prism includes a second surface, and the second surface is away from the lens, and the second surface is a curved surface with a curvature of CV2;

[0014] The sixth surface is a curved surface, and the curvature is CV6, 0.2≤|CV2 / CV6|≤2.

[0015] Optionally, centers of the second surface and the sixth surface are both located on the first optical axis;

[0016] The positive direction of the sag of the second surface and the sixth surface is a direction away from the human eye along the first optical axis.

[0017] Optionally, the cemented prism and the lens include three curved surfaces.

[0018] Optionally, the second prism includes a seventh surface, and the seventh surface is a curved surface or a flat surface.

[0019] Optionally, the seventh surface is a curved surface, the center of the seventh surface is located on the second optical axis, and the positive direction of the sagittal height of the seventh surface is a direction along the second optical axis toward the first optical axis.

[0020] Optionally, the optical module further includes a display screen, and the display screen is located on one side of the seventh surface.

[0021] Optionally, an angle θ1 formed between the second surface and the vertical direction is an acute angle.

[0022] Optionally, an angle θ2 formed between the optical axis of the seventh surface and the horizontal direction is an acute angle.

[0023] Optionally, the chief ray of the 0-degree field of view coincides with the optical axes of the second surface, the sixth surface, and the seventh surface.

[0024] Optionally, the third surface and the fourth surface are planes.

[0025] Optionally, the effective focal length EFL of the optical module is 15.1 mm ≤ EFL ≤ 17.2 mm.

[0026] Optionally, a protective glass is provided on the light emitting surface of the display screen.

[0027] In a second aspect, the present application provides a near-eye display device, which includes the optical module as described in the first aspect.

[0028] The beneficial effects of this application are:

[0029] The optical module design provided in the embodiments of the present application is suitable for XR optical devices and has the advantages of compact structure, optimized imaging quality, and flexible optical architecture design. By combining a cemented prism and a lens arranged adjacently and spaced apart, a relatively small volume is achieved at a large field of view while maintaining good imaging quality. In addition, by precisely controlling the effective focal length ratio, setting a polarized reflective element and a phase retarder, and adjusting the shape and parameters of the curved surface, the performance and design freedom of the optical module in complex lighting environments are further improved, making it suitable for a variety of XR optical devices and capable of responding to future new technologies and application requirements.

[0030] 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

[0031] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0032] Figure 1 This is one of the structural diagrams of the optical module provided in an embodiment of the present application;

[0033] Figure 2 The second structural diagram of the optical module provided in the embodiment of the present application;

[0034] Figure 3 for Figure 2 MTF diagram of the optical module shown;

[0035] Figure 4 The third structural diagram of the optical module provided in the embodiment of the present application;

[0036] Figure 5 for Figure 4 MTF diagram of the optical module shown;

[0037] Figure 6 This is a fourth structural diagram of the optical module provided in an embodiment of the present application;

[0038] Figure 7 for Figure 6 MTF diagram of the optical module shown;

[0039] Figure 8 This is a fifth structural diagram of the optical module provided in an embodiment of the present application;

[0040] Figure 9 for Figure 8 MTF diagram of the optical module shown;

[0041] Figure 10 The sixth structural diagram of the optical module provided in the embodiment of the present application;

[0042] Figure 11 for Figure 10 MTF diagram of the optical module is shown.

[0043] Description of reference numerals:

[0044] 1. First prism; 2. Second prism; 3. Lens; 4. Beam splitter; 5. Phase retarder; 6. Polarized reflective element; 7. Display screen; 8. Protective glass;

[0045] S1, human eye; S2, second surface; S3, third surface; S4, fourth surface; S5, fifth surface; S6, sixth surface; S7, seventh surface. DETAILED DESCRIPTION

[0046] 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 arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0047] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0048] 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.

[0049] 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.

[0050] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0051] The optical module and near-eye display device provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0052] According to one embodiment of the present application, an optical module is provided. Figure 1The optical module includes adjacent and spaced cemented prisms and a lens 3; the cemented prism includes a first prism 1, a polarizing reflective element 6, and a second prism 2 arranged in sequence, the lens 3 is located on the side of the second prism 2 away from the first prism 1, and a phase retarder 5 is provided between the lens 3 and the second prism 2; the lens 3 includes a fifth surface S5 and a sixth surface S6, the sixth surface S6 faces away from the cemented prism, and the sixth surface S6 is a partially reflecting surface; the cemented prism and the lens 3 include at least two curved surfaces; the optical module satisfies: 7.4≤|EFL 24 / EFL 56 |≤9.2; among them, EFL 24 is the effective focal length of the cemented prism, EFL 56 It is the effective focal length of light incident from the fifth surface S5, reflected by the sixth surface S6, and then emitted from the fifth surface S5.

[0053] The optical module provided in an embodiment of the present application is mainly composed of a glued prism and a lens 3; wherein the glued prism is mainly formed by gluing the first prism 1, the polarizing reflection element 6 and the second prism 2 in sequence. The glued prism and the lens 3 are adjacent to each other but maintain a certain interval. The lens 3 is specifically located on the side of the second prism 2 away from the first prism 1, and a phase retarder 5 is also provided between the lens 3 and the second prism 2. The lens 3 has a fifth surface S5 and a sixth surface S6, wherein the sixth surface S6 is away from the glued prism and is designed to be a partially reflecting surface. The optical module provided in the present application includes at least two curved surfaces to achieve precise manipulation of light.

[0054] The optical module provided in the embodiments of the present application can be applied to, for example, the field of XR technology, which covers VR technology, AR technology, and MR technology.

[0055] The optical module provided in the embodiment of the present application also satisfies a specific effective focal length ratio relationship, namely 7.4≤|EFL 24 / EFL 56 |≤9.2; among them, EFL 24 represents the effective focal length of the cemented prism, i.e. Figure 1 , EFL 24 represents the effective focal length of the light incident from the second surface S2 of the first prism 1 and emitted from the fourth surface S4 of the second prism 2; and EFL 56 = represents the effective focal length of light incident from the fifth surface S5 of the lens 3, reflected from the sixth surface S6, and then emitted from the fifth surface S5 (the light is folded within the third lens 3). Setting this proportional relationship helps further optimize the light transmission path and imaging quality.

[0056] The optical module provided in the embodiments of the present application includes multiple optical elements, and each optical element is analyzed below.

[0057] The optical module of the embodiment of the present application includes a cemented prism. Figure 1 The glued prism is one of the core optical elements of the entire optical module. It is composed of a first prism 1, a polarizing reflection element 6 and a second prism 2 glued together in sequence. The elements are closely adjacent to each other to ensure the normal transmission of light.

[0058] The polarizing reflective element 6 is located between the first prism 1 and the second prism 2 and is used to precisely control the polarization state of light. It selectively reflects or transmits light of a specific polarization direction, thereby optimizing the light transmission path and imaging quality. The design of the polarizing reflective element requires consideration of factors such as its reflectivity, transmittance, and polarization performance. For example, the polarizing reflective element 6 may be a polarizing reflective film.

[0059] The first prism 1 , the second prism 2 and the polarized reflective element 6 are combined to ensure that light can be accurately transmitted to the human eye S1 .

[0060] The optical module of the embodiment of the present application includes a lens 3, please continue to refer to Figure 1 Specifically, the lens 3 is located on the side of the second prism 2 away from the first prism 1. It is another important optical component in the entire optical module, responsible for receiving light from the cemented prisms and focusing it onto the imaging surface. The design of the lens requires consideration of factors such as focal length, curvature, material, and thickness to ensure image quality.

[0061] Specifically, see Figure 1 The lens 3 includes two surfaces: a fifth surface S5 and a sixth surface S6. The fifth surface S5 serves as the entrance for light to enter the lens 3. Factors such as its curvature and surface shape must be considered to optimize the refraction and focusing effects of the light. The sixth surface S6 is a partially reflective surface responsible for reflecting light back into the lens 3 to achieve multiple reflections and refractions. Its design must consider factors such as reflectivity, transmittance, and surface shape to ensure that light can be properly transmitted and focused.

[0062] The optical module of the present embodiment also includes several key optical film materials, such as a phase retarder 5. Specifically, the phase retarder 5 is located between the lens 3 and the second prism 2 and is used to precisely control the phase difference of light. By adjusting the phase difference of light, it can optimize imaging quality and reduce problems such as aberrations and distortion. The phase retarder 5 can be, for example, a quarter-wave plate.

[0063] Of course, the phase retarder 5 can be adjusted to a half-wave plate or the like according to requirements, and this application does not impose any limitation on this.

[0064] The optical module provided in an embodiment of the present application includes a first prism 1, a second prism 2 and a lens 3, wherein the first prism 1 and the second prism 2 are glued to each other, and the lens 3 is independently arranged on one side of the second prism 2. The glued prism and the lens 3 contain at least two curved surfaces, which are designed to achieve precise manipulation of light. For example, by adjusting factors such as the curvature, shape and position of the curved surface, the refraction, reflection and focusing effects of light can be optimized, thereby improving the imaging quality. The curved surface design can also increase the design flexibility and adaptability of the optical module.

[0065] The optical module provided in the embodiment of the present application satisfies a specific effective focal length ratio relationship, namely 7.4≤|EFL 24 / EFL 56 |≤9.2. This ratio helps to better optimize the light transmission path and imaging quality. The specific analysis is as follows:

[0066] Within the above scope, EFL 24 with EFL 56 The proportional relationship between the two is finely adjusted, which helps reduce aberrations such as distortion and chromatic aberration, thereby improving overall imaging quality. This proportional control designed in this application makes the transmission of light between the cemented prism and the lens 3 more stable, helps reduce light scattering and loss, and thus improves image clarity.

[0067] By optimizing EFL 24 with EFL 56 The ratio range can further reduce the volume of the entire optical module while maintaining good image quality. This is particularly important for near-eye display systems because it helps reduce the weight and volume of the device and improves wearing comfort.

[0068] The specific effective focal length ratio relationship of the optical module provided in the embodiment of the present application can also be extended to 7.5≤|EFL 24 / EFL 56 |≤63.5.

[0069] Compared with the small range of ratios, 7.5≤|EFL 24 / EFL 56 The wider ratio range of |≤63.5 provides greater design flexibility, allowing EFL to be adjusted according to specific needs in different application scenarios. 24 with EFL 56This makes the optical module applicable to a wider range of near-eye display systems, including devices of different sizes, resolutions and performance requirements.

[0070] The small range of ratios described in this application (i.e., 7.4≤|EFL 24 / EFL 56 |≤9.2) is an optimized solution that balances image quality and size within this wide range. By optimizing the effective focal length ratio, a more compact optical design can be achieved while maintaining high-quality imaging.

[0071] In summary, the ratio in a small range (7.4≤|EFL 24 / EFL 56 |≤9.2) provides a refined optical design that helps optimize imaging quality and volume. A wide range of ratios (7.5≤|EFL 24 / EFL 56 |≤63.5) provides wider applicability and design flexibility. The small range of ratios is the result of fine-tuning the optical module over a large range.

[0072] The optical module provided in the embodiments of the present application has a compact structure. Specifically, by using a cemented prism and a lens 3 disposed adjacently and spaced apart, combined with at least two curved surfaces, the entire optical module maintains a compact structure while efficiently manipulating light and achieving clear imaging at a wide field of view.

[0073] The optical module provided by the embodiments of the present application features excellent imaging quality. Specifically, the sixth surface S6 of the lens 3 is designed as a partially reflective surface. This, in conjunction with the cemented prism (including the polarizing reflective element 6) and the phase retarder 5, precisely controls the reflection and refraction paths of light, significantly improving imaging quality. Furthermore, by optimizing the effective focal length ratio, aberrations and distortion are further reduced, resulting in clearer and more stable imaging.

[0074] In the optical module provided by the embodiment of the present application, the polarization reflective element 6 in the cemented prism is used in conjunction with the phase retarder 5 to achieve precise control of the polarization state of light. This helps to reduce the influence of stray light and improve the imaging quality of the optical module.

[0075] Furthermore, because the optical module includes at least two curved surfaces and optical performance can be optimized by adjusting parameters such as the material and size of the lens 3 and each prism, it offers a high degree of design flexibility. This allows the optical module to adapt to different application scenarios and requirements, providing more possibilities for the development of XR optical devices.

[0076] In summary, the optical module provided in this embodiment has technical effects such as compact structure, excellent imaging quality and high design flexibility, and provides new technology for the development of XR optical equipment.

[0077] In some examples of this application, see Figure 1 The second prism 2 includes a fourth surface S4, and an air gap is set between the fourth surface S4 and the fifth surface S5.

[0078] In the example of the present application, an air gap is intentionally provided between the fourth surface S4 of the second prism 2 and the fifth surface S5 of the lens 3 , so as to enable light to be totally reflected on the fourth surface S4 .

[0079] Specifically, the presence of an air gap between the fourth surface S4 and the fifth surface S5 allows light to encounter interfaces with media of different refractive indices when propagating from the fourth surface S4 to the fifth surface S5. Due to the large difference in refractive index between air and the prism material (such as EP8000), when light is incident from the prism material (high refractive index) into air (low refractive index) and then back into the prism material, total internal reflection occurs if the angle of incidence is greater than the critical angle. This design is crucial to the light transmission path in this application because it ensures that light can be transmitted within the prism according to the predetermined path.

[0080] By providing an air gap between the fourth surface S4 and the fifth surface S5, the light transmission path can be precisely controlled. This helps reduce light scattering and loss within the second prism 2, thereby improving light utilization efficiency. Furthermore, the presence of the air gap further stabilizes light transmission within the second prism 2, reducing light deviation and distortion caused by changes in refractive index.

[0081] The realization of total internal reflection and the optimization of the light transmission path jointly improve the imaging quality. Because the light can be transmitted along the predetermined path, the clarity of the image can be ensured during the transmission process.

[0082] In some examples of this application, see Figure 1 The sixth surface S6 is provided with a spectroscopic element 4, the phase retarder 5 is provided on the fifth surface S5, the bonding surface between the first prism 1 and the second prism 2 is the third surface S3, and the polarizing reflection element 6 is provided on the third surface S3.

[0083] According to the examples of this application, see Figure 1The sixth surface S6 is a surface of the reflective lens, i.e., the lens 3, and is a partially reflective surface. The partial reflective function of the sixth surface S6 enables mounting or coating a beam splitter 4 thereon. The beam splitter 4, such as a semi-transparent and semi-reflective film, can split light from the display screen 7 into different paths to achieve a specific display effect.

[0084] See also Figure 1 The fifth surface S5 is another surface of the lens 3, and the phase retarder 5 can be mounted on this fifth surface S5. The phase retarder 5 is, for example, a quarter-wave plate. The phase retarder 5 is used to change the phase of light, thereby regulating the polarization state of the light. This is very critical in the entire optical module, as controlling the polarization state can optimize the folding and reflection of the light path, which helps improve image clarity and brightness.

[0085] Please continue to see Figure 1 The bonding surface between the first prism 1 and the second prism 2 forms a third surface S3. This bonding surface is a critical portion of the light path, ensuring a smooth transition of light between the two prisms. The polarizing reflective element 6, such as a polarizing reflective film, is disposed on the third surface S3. The polarizing reflective element 6 can reflect or transmit light depending on its polarization state.

[0086] In the optical module provided in the embodiment of the present application, the combination of the spectroscopic element 4, the phase retarder 5 and the polarized reflective element 6 realizes precise control and optimization of light, thereby improving the display effect, image quality and user experience of the optical module.

[0087] In addition, in the present application, the light splitting element 4, the phase retarder 5 and the polarization reflection element 6 are attached to the lens and the prism, which can reduce the assembly process and improve the assembly efficiency.

[0088] In some examples of the present application, the first prism 1 includes a second surface S2, and the second surface S2 is away from the lens 3, the second surface S2 is a curved surface, and the curvature is CV2; the sixth surface S6 is a curved surface, and the curvature is CV6, 0.2≤|CV2 / CV6|≤2.

[0089] In the example of the present application, the second surface S2 of the first prism 1 is located on the side away from the lens 3 and is designed as a curved surface with a curvature marked as CV2. At the same time, the sixth surface S6 of the lens 3, as a part of the lens 3, can also be designed as a curved surface with a curvature of CV6.

[0090] In this example, a proportional relationship is proposed, namely 0.2≤|CV2 / CV6|≤ 2. This proportional range defines the relative size of the curvatures of the second surface S2 and the sixth surface S6, providing guidance for optimizing the volume of the optical module.

[0091] By precisely controlling the curvature ratio of the second surface S2 and the sixth surface S6, the light path can be significantly optimized. This optimization ensures high efficiency and accuracy of light propagating between the first prism 1 and the lens 3, reducing unnecessary scattering and loss. The optimized light path helps improve image clarity and enhance the user's visual experience.

[0092] Proper curvature ratios help improve image quality. When light passes through prism and lens surfaces with appropriate curvature, it better maintains its focus, reducing aberrations and distortion. This is particularly important for optical modules, as it directly impacts the image quality and visual experience perceived by the user. By improving image quality, optical modules can provide users with a more immersive visual experience.

[0093] While maintaining image quality, by optimizing the curved surface design of the first prism 1 and the lens 3 (i.e., controlling the ratio of CV2 to CV6), the volume of the optical module can be reduced to a certain extent. This volume reduction is crucial for improving the wearing comfort of near-eye display devices. Users can use the device more easily without sacrificing optical performance.

[0094] Furthermore, while maintaining a compact size and high image quality, the optical module's field of view can be expanded to a certain extent by optimizing the curved surface design (controlling the ratio of CV2 to CV6). This expanded field of view allows users to observe clear image content within a wider viewing angle, which is crucial for enhancing the immersive experience of near-eye display devices.

[0095] Furthermore, 1.64≤|CV2 / CV6|≤1.86. By further optimizing this range, the field of view of the optical module can be maximized while ensuring a small size and high-quality imaging.

[0096] In some examples of the present application, the centers of the second surface S2 and the sixth surface S6 are both located on the first optical axis; the positive direction of the sag height of the second surface S2 and the sixth surface S6 is the direction away from the human eye S1 along the first optical axis.

[0097] The centers of the second surface S2 and the sixth surface S6 are both located on the first optical axis, which means that the center points of the two surfaces are on the same straight line, which is the optical axis.

[0098] Sagitta is a parameter used to describe the shape of a curved surface. In this example of the present application, the second surface S2 and the sixth surface S6 are both curved surfaces, and the positive direction of the sagitta of the second surface S2 and the sixth surface S6 is along the first optical axis, away from the human eye S1. This means that when the human eye S1 views these two surfaces, their curved shapes are convex away from the human eye (the sagitta is positive).

[0099] Combine Figure 1 , the positive direction of the sagittal height of the second surface S2 and the sixth surface S6 is to the right.

[0100] In this application, the design of the sagittal height of the second surface S2 of the first prism 1 and the sixth surface S6 of the lens 3 can optimize the light path. Specifically, the sagittal height design can control the angles of refraction and reflection of light when passing through the second surface S2 and the sixth surface S6, thereby optimizing the light path. This helps ensure that light propagates along the intended path, reduces unnecessary scattering and loss, and improves the light energy utilization efficiency of the entire optical module.

[0101] According to this example of the present application, a reasonable sag design can also reduce aberrations and distortions, thereby improving imaging quality. Specifically, when light passes through a surface with a reasonable sag, its focusing performance can be better maintained, making the image clearer and more accurate.

[0102] By optimizing the light path and improving imaging quality, the sag design of the second surface S2 and the sixth surface S6 can enhance the user's visual experience. The user will be able to observe clearer and more immersive images, which is particularly important for near-eye display devices.

[0103] In addition, the design of the vector height in this example of the present application helps to improve the overall performance of the optical module, including optical parameters such as field of view, resolution, and contrast.

[0104] In some examples of the present application, the cemented prism and the lens 3 include three curved surfaces.

[0105] In optical modules, the advantages of having multiple curved surfaces include many aspects, which are described below.

[0106] (1) From the perspective of improving imaging quality, multiple curved surfaces can more accurately control the refraction and reflection paths of light, thereby reducing aberrations and distortions and improving imaging quality.

[0107] (2) From the perspective of enhancing the design flexibility of optical modules: More curved surfaces mean more design parameters can be adjusted, thereby enhancing the design flexibility of the module. For example, the performance of the module, such as field of view and resolution, can be optimized by adjusting the curved surface parameters.

[0108] In addition, in some complex application scenarios, such as near-eye display devices that require a large field of view or high resolution, multiple curved surfaces can provide better optical performance.

[0109] However, in optical modules, too many curved surfaces can also lead to some defects, as detailed below:

[0110] (1) Multiple curved surfaces mean more complex optical designs, requiring more calculations and optimization work. This can lead to longer optical design cycles and increased design costs.

[0111] (2) Multiple curved surfaces increase the difficulty of processing and assembly, requiring higher precision and more complex processes. This will lead to increased production costs and a certain risk of processing errors.

[0112] (3) The increase in the number of curved surfaces may lead to an increase in the weight and volume of optical components, which is not conducive to lightweight and miniaturized near-eye display devices.

[0113] The optical module provided in the embodiment of the present application reasonably controls the number of curved surfaces. Specifically, the optical module includes at least two curved surfaces and can include at most three curved surfaces. That is, the optical module of the present application includes 2 to 3 curved surfaces. This design can bring the following technical effects:

[0114] (1) The design of 2 to 3 curved surfaces can optimize the light path while ensuring effective light transmission, reduce unnecessary refraction and reflection, and thus reduce light loss. By precisely designing the shape and parameters of the curved surfaces, aberrations and distortion can be reduced, image quality can be improved, and a clearer visual experience can be provided to users.

[0115] (2) Compared with designs with more curved surfaces, optical modules with 2 to 3 curved surfaces are simpler to design and process. This not only reduces design costs, but also reduces the complexity and potential errors in the processing process, thereby improving production efficiency and yield rate.

[0116] (3) The design of 2 to 3 curved surfaces enables the optical module to have better flexibility and adaptability while maintaining certain performance.

[0117] It should be noted that having more or fewer curved surfaces in an optical module has its advantages and disadvantages. In practical applications, the optimal number of curved surfaces should be selected based on a comprehensive consideration of factors such as specific requirements, design costs, production costs, and system performance.

[0118] In some examples of this application, see Figure 1 The second prism 2 includes a seventh surface S7, and the seventh surface S7 is a curved surface or a flat surface.

[0119] The top surface of the second prism 2 is a seventh surface S7 . The design of the seventh surface S7 is relatively flexible, and it can be a flat surface or a curved surface.

[0120] It should be noted that when the optical module includes three curved surfaces, one curved surface is the second surface S2 of the first prism 1 , another curved surface is the sixth surface S6 of the lens 3 , and the third curved surface is the seventh surface S7 of the second prism 2 .

[0121] In some examples of the present application, the seventh surface S7 is a curved surface, the center of the seventh surface S7 is located on the second optical axis, and the positive direction of the sag height of the seventh surface S7 is along the second optical axis toward the first optical axis. Figure 1 .

[0122] In the optical module of the present application, the seventh surface S7 serves as the curved surface portion of the second prism 2 and can cooperate with other optical elements to achieve more complex light control.

[0123] When the seventh surface S7 is a curved surface, based on the position of the seventh surface S7, its center is located on another optical axis, namely the second optical axis, and the positive direction of the sagittal height is designed to be toward the first optical axis. This design can more effectively guide light from the external display screen 7 into the human eye S1, while improving the imaging quality and the optical performance of the optical module.

[0124] The design of the seventh surface S7 of the second prism 2 in this example of the present application can enhance the ability to control light. This is because the curved surface can provide more flexible light control, help optimize the light path, reduce light loss, and improve imaging quality.

[0125] In some examples of this application, see Figure 1 The optical module further includes a display screen 7, which is located on one side of the seventh surface S7.

[0126] The display screen 7 is located on one side of the seventh surface S7. This arrangement means that light emitted from the display screen 7 can directly enter the seventh surface S7. This arrangement reduces light loss during transmission and improves the optical module's light energy utilization. Whether the seventh surface S7 is flat or curved, it can effectively guide this light into the human eye S1, ensuring high-quality imaging results.

[0127] The control of light by the seventh surface S7 (especially when it is a curved surface) can further reduce aberrations and distortions, thereby improving the overall imaging quality.

[0128] It should be noted that the light emitted by the display screen 7 should be polarized light when entering the second prism 2 from the seventh surface S7.

[0129] In some examples of this application, see Figure 1 , the angle θ1 formed between the second surface S2 and the vertical direction is an acute angle.

[0130] See also Figure 1 , the vertical direction in this example of the present application refers to the direction perpendicular to the first optical axis.

[0131] In the example of this application, the angle θ1 formed between the second surface S2 and the vertical direction is an acute angle. This design means that the second surface S2 is not parallel or perpendicular to the vertical direction, but has a certain inclination angle. This design can bring the following technical effects:

[0132] (1) Optimize the light refraction path:

[0133] When light travels from the interior of the first prism toward the second surface S2, due to the acute angle θ1, the light is refracted upon passing through the second surface S2, and the direction of the refracted light is more consistent with the observation requirements of the human eye S1. This optimized refraction path reduces light loss within the prism, improves light energy utilization, and thus enhances image brightness and clarity.

[0134] (2) Reduce the volume of the optical module:

[0135] By adjusting the angle θ1, the volume of the prism can be appropriately reduced while maintaining image quality. This is of great significance for the lightweight and miniaturized design of the optical module, helping to improve user wearing comfort.

[0136] In some examples of this application, see Figure 1 The angle θ2 formed by the optical axis of the seventh surface S7 and the horizontal direction is an acute angle.

[0137] See also Figure 1 , the horizontal direction in this example of the present application refers to the direction parallel to the first optical axis.

[0138] In this example of the present application, it is mentioned that the angle θ2 formed between the optical axis of the seventh surface S7 and the horizontal direction is an acute angle. This design indicates that the seventh surface S7 is not parallel or perpendicular to the horizontal direction, but has a certain inclination angle. This design can bring the following technical effects:

[0139] The acute angle θ2 helps optimize the transmission path of light from the display screen 7 to the seventh surface S7. Specifically, when light is emitted from the display screen 7 and refracted by the seventh surface S7, a clearer image can be formed.

[0140] By adjusting the angle θ2, the field of view of the optical module can be expanded to a certain extent. This allows users to observe clear images in a wider range, enhancing the immersiveness of the system.

[0141] The clear imaging, expanded field of view, and optimized light transmission path enhance the overall user experience. Users can wear near-eye display devices more comfortably and conveniently, and enjoy a more realistic and immersive visual experience.

[0142] In summary, the design of the second surface S2 with an acute angle θ1 with the vertical direction and the design of the seventh surface S7 with an acute angle θ2 with the optical axis with the horizontal direction have produced significant technical benefits in optimizing the light refraction path, reducing module volume, enhancing imaging effects, expanding the field of view, and improving the user visual experience. These benefits have jointly promoted the development of near-eye optical display technology.

[0143] In some examples of the present application, the chief ray of the 0-degree field of view coincides with the optical axes of the second surface S2 , the sixth surface S6 , and the seventh surface S7 .

[0144] According to this example of the present application, during the propagation process, although the light passes through the prism and lens, it always remains in a coaxial optical path, that is, the light always passes through the optical axis of all elements instead of forming an off-axis system.

[0145] The principal ray at a zero-degree field of view coincides with the optical axes of all critical surfaces, ensuring minimal aberration and distortion as the light passes through these surfaces. This design significantly improves image quality, resulting in clearer images. The coaxial optical path design greatly simplifies the optical design and calculation process of the optical module.

[0146] Light always propagates along the optical axis, reducing losses at the edges of prisms and lenses. This helps improve light energy utilization, allowing more light to reach the human eye and enhancing the imaging brightness of the optical module.

[0147] The coaxial optical path design simplifies the manufacturing and assembly process of optical components. Optical components can be positioned and fixed more accurately, thereby improving the stability and reliability of the entire optical module.

[0148] In some examples of the present application, the third surface S3 and the fourth surface S4 are planes.

[0149] Flat surfaces are easier to machine and manufacture than curved surfaces or other complex shapes, which helps reduce production costs.

[0150] By designing the third surface S3 and the fourth surface S4 as planes, the aberration and distortion generated when light passes through these surfaces can be reduced, thereby improving the imaging quality.

[0151] The flat design makes the light propagation path inside the prism more stable and controllable. This helps ensure that light can propagate along the predetermined path, reducing light loss and improving light energy utilization.

[0152] Furthermore, the third surface S3 serves as the bonding surface between the first prism 1 and the second prism 2. Designing it as a flat surface ensures stability and accuracy during the bonding process. A flat bonding surface facilitates precise docking and fixation, minimizing optical performance degradation caused by shape mismatch or misalignment. A flat bonding surface also reduces light scattering and reflection at the prism interface, minimizing light energy loss.

[0153] The fourth surface S4 is a total reflection surface. The advantages of designing it as a plane are:

[0154] (1) Improved total internal reflection efficiency: When light travels from a denser medium to a less dense medium, total internal reflection occurs if the incident angle is greater than or equal to the critical angle. A flat total internal reflection surface ensures that light enters at a constant angle, making it easier to meet the conditions for total internal reflection and improving the efficiency of total internal reflection.

[0155] (2) Reduce aberration and distortion: A flat total reflection surface is easier to control aberration and distortion than a curved surface or other complex shapes. This helps ensure that light maintains its original directionality and imaging quality after total reflection.

[0156] In summary, designing the third surface S3 as a planar bonding surface can bring benefits such as structural stability and optical performance optimization; while designing the fourth surface S4 as a planar total reflection surface can improve total reflection efficiency, reduce aberration and distortion, etc.

[0157] In some examples of the present application, the effective focal length EFL of the optical module is 15.1 mm ≤ EFL ≤ 17.2 mm.

[0158] Focal length is one of the key factors affecting image quality. In this application, by setting an appropriate effective focal length range, it is possible to ensure that light can form a clear, distortion-free image after passing through the optical module.

[0159] In addition, the focal length is closely related to the volume of the optical module. A shorter focal length generally means a smaller optical module. In this application, by setting the focal length range between 15.1mm and 17.2mm, the optical module can be miniaturized while ensuring image quality and field of view, thereby improving the portability and comfort of the product.

[0160] In some examples of the present application, a protective glass 8 is provided on the light emitting surface of the display screen 7 .

[0161] The display screen 7 is an important component of the optical module, and its display effect directly affects the user experience. The protective glass 8 acts as a protective barrier for the display screen 7, which can resist external damage such as scratches, impacts, and wear, thereby extending the service life of the display screen 7.

[0162] According to another embodiment of the present application, a near-eye display device is provided, which includes the optical module as described above.

[0163] The near-eye display device is, for example, an AR device or an XR device.

[0164] The optical module provided by the present application is described in detail below through Examples 1 to 5.

[0165] Example 1

[0166] See also Figure 2 The optical module provided in this embodiment 1 includes a cemented prism and a lens 3 that are adjacently and spaced apart, and also includes a display screen 7, and a protective glass 8 is provided on the light emitting surface of the display screen 7;

[0167] The cemented prism comprises a first prism 1, a polarized reflective element 6, and a second prism 2 that are cemented in sequence, and the lens 3 is located on a side of the second prism 2 away from the first prism 1;

[0168] The lens 3 includes a fifth surface S5 and a sixth surface S6. The sixth surface S6 faces away from the cemented prism. A beam splitter 4 is disposed on the sixth surface S6. The sixth surface S6 is a partially reflective surface. A phase retarder 5 is disposed on the fifth surface S5.

[0169] The second prism 2 includes a fourth surface S4 and a seventh surface S7; an air gap is provided between the fourth surface S4 and the fifth surface S5 so that the fourth surface S4 forms a total reflection surface; the seventh surface S7 is a curved surface, and an angle θ2 formed between the optical axis of the seventh surface S7 and the horizontal direction is an acute angle;

[0170] The bonding surface between the first prism 1 and the second prism 2 is a third surface S3, and the polarizing reflective element 6 is disposed on the third surface S3; the first prism 1 includes a second surface S2, and an angle θ1 formed between the second surface S2 and the vertical direction is an acute angle;

[0171] Wherein, the third surface S3 and the fourth surface S4 are planes;

[0172] The chief ray of the 0-degree field of view coincides with the optical axes of the second surface S2 , the sixth surface S6 , and the seventh surface S7 .

[0173] The parameters of the optical elements in the optical module provided in this embodiment 1 are shown in Table 1.

[0174] Table 1

[0175]

[0176]

[0177] For Table 1, see Figure 1 The distance from S0 to S1 is t0, the distance from S1 to S2 is t1, the distance from S2 to S3 is t2, the distance from S3 to S4 is t3, the distance from S4 to S5 is t4, the distance from S5 to S6 is t5, the distance from S3 to S7 is t6, the distance from S7 to S8 is t7, and the distance from S8 to S9 is t8.

[0178] Other parameters in this embodiment 1, such as |EFL 24 / EFL 56 For details on parameters such as |, |CV2 / CV6| and EFL, please refer to Table 6 shown after Example 5.

[0179] See also Figure 3 The MTF diagram of the optical module is shown. Figure 3 It can be seen that at lower spatial frequencies, the MTF value may be close to 1, which means that the optical module of Example 1 can well transmit these low-frequency details.

[0180] Example 2

[0181] See also Figure 4 The optical module shown in this embodiment 2 has an optical architecture that is the same as that of the above-mentioned embodiment 1. The difference between the two lies in the optical parameters in the optical module. Please refer to Table 2 for the optical parameters of the optical module provided in this embodiment 2.

[0182] Table 2

[0183]

[0184] For Table 2, see Figure 4 The distance from S0 to S1 is t0, the distance from S1 to S2 is t1, the distance from S2 to S3 is t2, the distance from S3 to S4 is t3, the distance from S4 to S5 is t4, the distance from S5 to S6 is t5, the distance from S3 to S7 is t6, the distance from S7 to S8 is t7, and the distance from S8 to S9 is t8.

[0185] Other parameters in this embodiment 2, such as |EFL 24 / EFL 56 For details on parameters such as |, |CV2 / CV6| and EFL, please refer to Table 6 shown after Example 5.

[0186] See also Figure 5 The MTF diagram of the optical module is shown. Figure 5 It can be seen that at lower spatial frequencies, the MTF value may be close to 1, which means that the optical module of the second embodiment can well transmit these low-frequency details.

[0187] Example 3

[0188] See also Figure 6 The optical module shown in this embodiment 3 has an optical architecture that is the same as that of embodiment 1. The difference between the two lies in the optical parameters in the optical module. Please refer to Table 3 for the optical parameters of the optical module provided in this embodiment 3.

[0189] Table 3

[0190]

[0191] For Table 3, see Figure 6 The distance from S0 to S1 is t0, the distance from S1 to S2 is t1, the distance from S2 to S3 is t2, the distance from S3 to S4 is t3, the distance from S4 to S5 is t4, the distance from S5 to S6 is t5, the distance from S3 to S7 is t6, the distance from S7 to S8 is t7, and the distance from S8 to S9 is t8.

[0192] Other parameters in this embodiment 3, such as |EFL 24 / EFL 56 For details on parameters such as |, |CV2 / CV6| and EFL, please refer to Table 6 shown after Example 5.

[0193] See also Figure 7 The MTF diagram of the optical module is shown. Figure 7 It can be seen that at lower spatial frequencies, the MTF value may be close to 1, which means that the optical module of this embodiment 3 can well transmit these low-frequency details.

[0194] Example 4

[0195] See also Figure 8 The optical module shown in this embodiment 4 has an optical architecture that is the same as that of embodiment 1. The difference between the two lies in the optical parameters in the optical module. Please refer to Table 4 for the optical parameters of the optical module provided in this embodiment 4.

[0196] Table 4

[0197]

[0198] For Table 4, see Figure 8The distance from S0 to S1 is t0, the distance from S1 to S2 is t1, the distance from S2 to S3 is t2, the distance from S3 to S4 is t3, the distance from S4 to S5 is t4, the distance from S5 to S6 is t5, the distance from S3 to S7 is t6, the distance from S7 to S8 is t7, and the distance from S8 to S9 is t8.

[0199] Other parameters in this embodiment 4, such as |EFL 24 / EFL 56 For details on parameters such as |, |CV2 / CV6| and EFL, please refer to Table 6 shown after Example 5.

[0200] See also Figure 9 The MTF diagram of the optical module is shown. Figure 9 It can be seen that at lower spatial frequencies, the MTF value may be close to 1, which means that the optical module of Example 4 can well transmit these low-frequency details.

[0201] Example 5

[0202] See also Figure 10 The optical module shown in this embodiment 5 has an optical architecture that is the same as that of embodiment 1. The difference between the two lies in the optical parameters in the optical module. Please refer to Table 5 for the optical parameters of the optical module provided in this embodiment 5.

[0203] Table 5

[0204]

[0205] For Table 5, see Figure 10 The distance from S0 to S1 is t0, the distance from S1 to S2 is t1, the distance from S2 to S3 is t2, the distance from S3 to S4 is t3, the distance from S4 to S5 is t4, the distance from S5 to S6 is t5, the distance from S3 to S7 is t6, the distance from S7 to S8 is t7, and the distance from S8 to S9 is t8.

[0206] Other parameters in this embodiment 5, such as |EFL 24 / EFL 56 For details on parameters such as |, |CV2 / CV6| and EFL, please refer to Table 6 shown after Example 5.

[0207] See also Figure 11 The MTF diagram of the optical module is shown. Figure 11 It can be seen that at lower spatial frequencies, the MTF value may be close to 1, which means that the optical module of Example 5 can well transmit these low-frequency details.

[0208] Table 6 Parameters of Examples 1 to 5

[0209] <![CDATA[CV2]]> CV6 <![CDATA[CV2 / CV6]]> <![CDATA[EFL 24 ]]> <![CDATA[EFL 56 ]]> <![CDATA[EFL 24 / EFL 56 ]]> EFL Example 1 0.029 -0.0176 -1.6436 167.676 18.3365 9.1444 15.1767 Example 2 0.0298 -0.0161 -1.8551 163.1085 20.1321 8.1019 16.0837 Example 3 0.0297 -0.0148 -2.0054 163.5391 21.8213 7.4945 16.9458 Example 4 0.0049 -0.0204 -0.2423 1005.7909 15.8813 63.3317 17.1268 Example 5 0.0119 -0.0196 -0.6101 415.7195 16.5285 25.1517 16.8944

[0210] 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.

[0211] 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 for illustration only and are not intended to limit the scope of the present application. It should be understood by those skilled in the art that the above examples 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 for XR optical equipment, characterized in that: It comprises cemented prisms and a lens (3) that are adjacent and spaced apart; The cemented prism comprises a first prism (1), a polarized reflection element (6), and a second prism (2) arranged in sequence; the lens (3) is located on a side of the second prism (2) away from the first prism (1); and a phase retarder (5) is provided between the lens (3) and the second prism (2); The lens (3) comprises a fifth surface (S5) and a sixth surface (S6), the sixth surface (S6) faces away from the cemented prism, and the sixth surface (S6) is a partially reflecting surface; The cemented prism and the lens (3) include at least two curved surfaces; The optical module satisfies: 7.4≤|EFL 24 / EFL 56 |≤9.2; among them, EFL 24 is the effective focal length of the cemented prism, EFL 56 It is the effective focal length of light incident from the fifth surface (S5), reflected from the sixth surface (S6), and then emitted from the fifth surface (S5).

2. The optical module according to claim 1, wherein: The second prism (2) comprises a fourth surface (S4), and an air gap is provided between the fourth surface (S4) and the fifth surface (S5).

3. The optical module according to claim 2, wherein: A light splitting element (4) is provided on the sixth surface (S6); The phase retarder (5) is arranged on the fifth surface (S5); The bonding surface between the first prism (1) and the second prism (2) is a third surface (S3), and the polarized reflection element (6) is arranged on the third surface (S3).

4. The optical module according to claim 3, wherein: The first prism (1) includes a second surface (S2), and the second surface (S2) is far away from the lens (3), and the second surface (S2) is a curved surface with a curvature CV2; The sixth surface (S6) is a curved surface, and the curvature is CV6, 0.2≤|CV2 / CV6|≤2.

5. The optical module according to claim 4, wherein: The centers of the second surface (S2) and the sixth surface (S6) are both located on the first optical axis; The positive direction of the sagittal height of the second surface (S2) and the sixth surface (S6) is a direction away from the human eye (S1) along the first optical axis.

6. The optical module according to claim 5, wherein: The cemented prism and the lens (3) include three curved surfaces.

7. The optical module according to claim 6, wherein: The second prism (2) comprises a seventh surface (S7), and the seventh surface (S7) is a curved surface or a flat surface.

8. The optical module according to claim 7, wherein: The seventh surface (S7) is a curved surface, the center of the seventh surface (S7) is located on the second optical axis, and the positive direction of the sagittal height of the seventh surface (S7) is the direction along the second optical axis toward the first optical axis.

9. The optical module according to claim 7, wherein: The optical module further comprises a display screen (7), and the display screen (7) is located on one side of the seventh surface (S7).

10. The optical module according to claim 9, wherein: An angle θ1 formed between the second surface (S2) and the vertical direction is an acute angle.

11. The optical module according to claim 10, wherein: An angle θ2 formed between the optical axis of the seventh surface (S7) and the horizontal direction is an acute angle.

12. The optical module according to claim 11, wherein: The chief ray of the 0-degree field of view coincides with the optical axes of the second surface (S2), the sixth surface (S6) and the seventh surface (S7).

13. The optical module according to claim 3, wherein: The third surface (S3) and the fourth surface (S4) are planes.

14. The optical module according to claim 9, wherein: The effective focal length EFL of the optical module is 15.1 mm ≤ EFL ≤ 17.2 mm.

15. The optical module according to claim 9, wherein: A protective glass (8) is provided on the light-emitting surface of the display screen (7).

16. A near-eye display device, characterized in that: The optical module comprises the optical module as claimed in any one of claims 1 to 15.

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