Optical module and near-to-eye display equipment

Abstract

The embodiment of the invention provides an optical module and near-to-eye display equipment. The optical module is used for XR optical equipment and comprises a cemented prism and a lens which are adjacent and arranged at an interval. The cemented prism comprises a first prism, a polarization reflection element and a second prism which are arranged in sequence, the lens is located on the side, away from the first prism, of the second prism, and a phase retarder is arranged between the lens and the second prism; the lens comprises a fifth surface and a sixth surface, the sixth surface deviates from the cemented prism, and the sixth surface is a partial reflection surface; the cemented prism and the lens comprise at least two curved surfaces; the optical module meets the condition that EFL24 / EFL56 is more than or equal to 7.4 and less than or equal to 9.2; eFL24 is the effective focal length of the cemented prism, and EFL56 is the effective focal length of light which enters from the fifth surface, is reflected by the sixth surface and then exits 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 concept of the metaverse, XR technology has developed rapidly. XR technology covers AR technology, VR technology and MR technology. As the core component of XR technology, the performance of the near-eye display system directly affects the user experience. However, existing near-eye display devices still have some problems in the design of optical modules, such as large size, poor imaging quality and limited field of view. Therefore, how to design an optical module with small size, high imaging quality and large field of view has become a technical problem that needs to be solved urgently. 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 for an XR optical device, and includes a cemented prism and a lens that are adjacently and spaced apart;

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

[0006] The lens comprises a fifth surface and a sixth surface, the sixth surface faces away from the cemented prism, and the sixth surface is a partial reflection 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; where EFL 24 is the effective focal length of the cemented prism, EFL 56 It is the effective focal length of the 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 arranged 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 far away from the lens, and the second surface is a curved surface, and the curvature is 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 vector 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 by 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, wherein the near-eye display device comprises 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 embodiment of the present application is suitable for XR optical equipment, and has the beneficial effects of compact structure, optimized imaging quality and flexible optical architecture design. Through the combination of a cemented prism and a lens that are adjacent 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 polarized reflection elements and phase delayers, 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 various XR optical equipment 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 the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0032] Figure 1 One of the structural schematic diagrams of the optical module provided in the 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 A fourth structural diagram of an 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 A fifth structural diagram of an optical module provided in an embodiment of the present application;

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

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

[0042] Fig.11 for Fig.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. Polarization reflection 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 arrangement 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 application, 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 as 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 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.

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

[0052] According to one embodiment of the present application, an optical module is provided. Figure 1, the optical module includes adjacent and spaced cemented prisms and a lens 3; the cemented prism includes a first prism 1, a polarized reflection 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 is away from the cemented prism, and the sixth surface S6 is a partial reflection 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; where EFL 24 is the effective focal length of the cemented prism, EFL 56 It is the effective focal length of the light incident from the fifth surface S5, reflected from the sixth surface S6, and then emitted from the fifth surface S5.

[0053] The optical module provided in the 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 polarized 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 as a partial reflection 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 includes 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; where 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 It represents the effective focal length of the light incident from the fifth surface S5 of the lens 3, reflected by the sixth surface S6, and then emitted from the fifth surface S5 (the light is folded in the third lens 3). The setting of this proportional relationship helps to further optimize the transmission path of the light and the imaging quality.

[0056] The optical module provided in the embodiment 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 formed by gluing a first prism 1, a polarized reflection element 6 and a second prism 2 in sequence. Each element is closely adjacent to each other to ensure the normal transmission of light.

[0058] The polarized reflective element 6 is located between the first prism 1 and the second prism 2, and is used to achieve precise control of the polarization state of the light. It can selectively reflect or transmit light of a specific polarization direction, thereby optimizing the transmission path and imaging quality of the light. The design of the polarized reflective element needs to consider factors such as its reflectivity, transmittance and polarization performance. The polarized reflective element 6 is, for example, a polarized reflective film.

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

[0060] The optical module of the present embodiment includes a lens 3. Please refer to Figure 1 The lens 3 is specifically located on the side of the second prism 2 away from the first prism 1. It is another important optical element in the entire optical module. It is responsible for receiving the light from the cemented prism and focusing it onto the imaging surface. The design of the lens needs to consider factors such as its focal length, curvature, material and thickness to ensure imaging 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 is the entrance for light to enter the lens 3. The fifth surface S5 needs to consider factors such as its curvature and surface shape to optimize the refraction and focusing effect of light. The sixth surface S6 is a partial reflection surface, which is responsible for reflecting the light back into the lens 3 to achieve multiple reflections and refractions of the light. Its design needs to consider factors such as reflectivity, transmittance and surface shape to ensure that the light can be correctly transmitted and focused.

[0062] The optical module of the embodiment of the present application also includes a plurality of 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 achieve precise control of the phase difference of light. It can optimize the imaging quality and reduce problems such as aberration and distortion by adjusting the phase difference of light. Among them. The phase retarder 5 is, 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 the 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 control 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 range, EFL 24 With EFL 56 The proportional relationship between the two is adjusted more finely, which helps to reduce aberrations such as distortion, chromatic aberration, etc., thereby improving the overall imaging quality. The proportional control designed in the present application makes the transmission of light between the cemented prism and the lens 3 more stable, helps to reduce the scattering and loss of light, thereby improving the clarity of the image.

[0067] By optimizing EFL 24 With EFL 56 The ratio range can further compress the volume of the entire optical module while maintaining good imaging quality. This is especially 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 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 |≤63.5This wider ratio range provides greater design flexibility, allowing EFL to be adjusted according to specific needs in different application scenarios 24 With EFL 56This enables the optical module to be 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 optimization solution to balance image quality and volume within this large range. By optimizing the effective focal length ratio, a more compact optical design can be achieved while ensuring high-quality imaging.

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

[0072] The optical module provided in the embodiment of the present application has the characteristic of compact structure. Specifically, by using a cemented prism and a lens 3 disposed adjacently and spaced apart, and by designing at least two curved surfaces, the entire optical module can efficiently manipulate light while maintaining a compact structure, thereby achieving clear imaging at a large field of view.

[0073] The optical module provided in the embodiment of the present application has the characteristic of excellent imaging quality. Specifically, the sixth surface S6 of the lens 3 is designed as a partial reflection surface, which is used in conjunction with the cemented prism (including the polarized reflection element 6) and the phase retarder 5 to accurately control the reflection and refraction paths of light, thereby significantly improving the imaging quality. At the same time, by optimizing the effective focal length ratio, aberrations and distortions are further reduced, making the imaging clearer and more stable.

[0074] In the optical module provided by the embodiment of the present application, the polarization reflection 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, which helps to reduce the influence of stray light and improve the imaging quality of the optical module.

[0075] In addition, since the optical module includes at least two curved surfaces, and the optical performance can be optimized by adjusting the material, size and other parameters of the lens 3 and each prism, it has a high degree of design flexibility. This enables the optical module to adapt to different application scenarios and requirements, providing more possibilities for the development of XR optical equipment.

[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 arranged 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 , the purpose of which is to enable the light to be totally reflected on the fourth surface S4 .

[0079] Specifically, the presence of the air gap between the fourth surface S4 and the fifth surface S5 enables the light to encounter a medium interface with a different refractive index when propagating from the fourth surface S4 to the fifth surface S5. Due to the large difference in refractive index between air and prism material (such as EP8000), when light is incident from the prism material (high refractive index) into the air (low refractive index) and then back into the prism material, total reflection will occur if the incident angle is greater than the critical angle. This design is crucial to the light transmission path in the present application because it ensures that the light can be transmitted inside the prism according to the predetermined path.

[0080] By providing an air gap between the fourth surface S4 and the fifth surface S5, the transmission path of the light can be precisely controlled. This helps to reduce the scattering and loss of light inside the second prism 2 and improve the utilization efficiency of light. At the same time, the presence of the air gap can also make the transmission of light inside the second prism 2 more stable, reducing the light deviation and distortion caused by the change of the refractive index.

[0081] The realization of total reflection and the optimization of the light transmission path improve the imaging quality. Since 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 beam splitter 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 polarized reflection element 6 is provided on the third surface S3.

[0083] According to the example 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 can be realized by mounting or coating a beam splitter 4 thereon. The beam splitter 4 is, for example, a semi-transparent and semi-reflective film, which can split the 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 the 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 the light, thereby regulating the polarization state of the light. This is very critical in the entire optical module, because the control of the polarization state can optimize the folding and reflection of the light path, which is conducive to improving the clarity and brightness of the image.

[0085] Please continue to see Figure 1 The bonding surface of the first prism 1 and the second prism 2 is the third surface S3, which is a key part in the light path, and ensures that the light smoothly transitions between the two prisms. The polarized reflection element 6 is disposed on the third surface S3, and the polarized reflection element 6 is, for example, a polarized reflection film. The polarized reflection element 6 can reflect or transmit light according to the polarization state of the light.

[0086] In the optical module provided in the embodiment of the present application, the combination of the beam splitter 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 far 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, and its curvature is 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, and the curvature is CV6.

[0090] In this example of the present application, a proportional relationship is proposed, that is, 0.2≤|CV2 / CV6|≤2. This proportional range defines the relative size between the curvatures of the second surface S2 and the sixth surface S6, and provides guidance for the volume optimization 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 that light can maintain high efficiency and accuracy when propagating between the first prism 1 and the lens 3, reducing unnecessary scattering and loss. The optimized light path helps to improve the clarity of the image and enhance the user's visual experience.

[0092] The proper curvature ratio helps improve the image quality. When light passes through the prism and lens surfaces with reasonable curvature, it can better maintain its focusing performance and reduce aberration and distortion. This is especially important for optical modules, which are directly related to the image quality and visual experience observed by users. By improving the image quality, the optical module can provide users with a more immersive visual effect.

[0093] While maintaining the imaging 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. The reduction in volume is of great significance for improving the wearing comfort of near-eye display devices. Users can use the device more easily without sacrificing optical performance.

[0094] In addition, while maintaining a small size and high imaging quality, the field of view of the optical module can be expanded to a certain extent by optimizing the curved surface design (controlling the ratio of CV2 to CV6). The expansion of the field of view allows users to observe clear image content within a wider viewing angle, which is of great significance for enhancing the immersiveness 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 expanded as much as possible while ensuring a small volume and high-quality imaging.

[0096] In some examples of the present application, centers of the second surface S2 and the sixth surface S6 are both located on the first optical axis; the positive direction of the vector 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, and the straight line is the optical axis.

[0098] The 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 the direction away from the human eye S1 along the first optical axis. This means that when the human eye S1 looks at these two surfaces, their curved surface shapes are convex in the direction away from the human eye (the sagitta is positive).

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

[0100] In the present application, the design of the sagitta 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 design of the sagitta can control the refraction and reflection angles of the light when passing through the second surface S2 and the sixth surface S6, thereby optimizing the light path. This helps to ensure that the light propagates along the expected path, reduce unnecessary scattering and loss, and improve the light energy utilization rate 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 imaging clearer and more accurate.

[0102] By optimizing the light path and improving the 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 an optical module, 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 flexibility of optical module design: More curved surfaces mean more design parameters that 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 bring some defects, as follows:

[0110] (1) Multiple curved surfaces mean more complex optical designs, which require more calculations and optimization work. This may 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 higher 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 may 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 distortions 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 the number of curved surfaces in an optical module has its own advantages and disadvantages. In practical applications, it is necessary to comprehensively consider factors such as specific needs, design costs, production costs, and system performance to select the most appropriate number of curved surfaces.

[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 vector height of the seventh surface S7 is the direction along the second optical axis toward the first optical axis, see 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 vector 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, 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 also includes a display screen 7, and the display screen 7 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 layout means that after the light is emitted from the display screen 7, it can directly enter the seventh surface S7. Such a layout reduces the loss of light during transmission and improves the light energy utilization rate of the optical module. Whether the seventh surface S7 is a flat surface or a curved surface, it can effectively guide the light into the human eye S1, ensuring high-quality imaging effects.

[0127] The control of light by the seventh surface S7 (especially when it is a curved surface) can further reduce aberration and distortion, 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 by 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 the present 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 is emitted from the first prism to the second surface S2, since the angle θ1 is an acute angle, the light will be refracted when passing through the second surface S2, and the direction of the refracted light will be more in line with the observation requirements of the human eye S1. This optimization of the refraction path can reduce the loss of light inside the prism, improve the utilization rate of light energy, and thus enhance the brightness and clarity of the image.

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

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

[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 by 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 design of the angle θ2 helps to optimize the transmission path of light from the display screen 7 to the seventh surface S7. Specifically, when the light is emitted from the display screen 7, it is refracted by the seventh surface S7 to form a clearer image.

[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 larger range and enhances the immersion of the system.

[0141] Clear imaging, expanded field of view, and optimized light transmission paths together 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 that the angle θ1 between the second surface S2 and the vertical direction is an acute angle and the angle θ2 between the optical axis of the seventh surface S7 and the horizontal direction is an acute angle has produced significant technical effects in optimizing the light refraction path, reducing the module volume, enhancing the imaging effect, expanding the field of view, and improving the user's visual experience. These effects 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 deflections of prisms and lenses, it always remains in a coaxial optical path, that is, the light always passes through the optical axes of all elements instead of forming an off-axis system.

[0145] The main light of the 0-degree field of view coincides with the optical axis of all key surfaces, which ensures that the light has minimal aberration and distortion when passing through these surfaces. This design can significantly improve the imaging quality and make the image clearer. The design of the coaxial optical path greatly simplifies the optical design and calculation process of the optical module.

[0146] The light always propagates along the optical axis, reducing the loss at the edge of the prism and lens. This helps to improve the utilization of light energy, allowing more light to reach the human eye and enhance the imaging brightness of the optical module.

[0147] The design of the coaxial optical path 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. This helps reduce production costs.

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

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

[0152] In addition, the third surface S3 is the bonding surface of the first prism 1 and the second prism 2. Designing it as a plane can ensure the stability and accuracy of the two prisms during the bonding process. The flat bonding surface is easier to achieve precise docking and fixation, reducing the degradation of optical performance caused by shape mismatch or misalignment. The flat bonding surface can reduce the scattering and reflection of light on the prism interface and reduce 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 reflection efficiency: When light is incident from a denser medium to a less dense medium, total reflection will occur if the incident angle is greater than or equal to the critical angle. A flat total reflection surface can ensure that the light is incident at a constant angle, making it easier to meet the conditions for total reflection and improving the efficiency of total reflection.

[0155] (2) Reduce aberration and distortion: It is easier to control aberration and distortion on a flat total reflection surface than on a curved surface or other complex shapes. This helps ensure that the light still 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 in terms of structural stability and optical performance optimization; and 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 imaging quality. In this application, by setting a suitable effective focal length range, it can be ensured 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 usually means a smaller optical module volume. In this application, by setting the focal length range between 15.1 mm and 17.2 mm, the miniaturization of the optical module can be achieved while ensuring the imaging 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 serves as a protective barrier for the display screen 7 and can resist external damages such as scratches, impacts and abrasion, 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 also provided, and the near-eye display device 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 which 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 glued prism comprises a first prism 1, a polarized reflection element 6 and a second prism 2 which are glued 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 is away from the cemented prism. A beam splitter 4 is disposed on the sixth surface S6. The sixth surface S6 is a partial reflection 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 by 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 polarized 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 each optical element 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 specific 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 in 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 this embodiment 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 specific 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 in 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 specific 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 in 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 8, 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.

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

[0200] See also Fig. 9 The MTF diagram of the optical module is shown in Fig. 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 transmit these low-frequency details well.

[0201] Example 5

[0202] See also Fig.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 Fig.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 specific parameters such as |, |CV2 / CV6| and EFL, please refer to Table 6 shown after Example 5.

[0207] See also Fig.11 The MTF diagram of the optical module is shown in Fig.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 this embodiment 5 can well transmit these low-frequency details.

[0208] Table 6 Parameters in 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 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 for XR optical equipment, characterized in that: It comprises cemented prisms and a lens (3) which are adjacent and spaced apart; The cemented prism comprises a first prism (1), a polarized reflection element (6) and a second prism (2) which are 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 partial reflection 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; where 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, characterized in that: 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, characterized in that: A light splitting element (4) is arranged 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, characterized in that: The first prism (1) comprises 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, and the curvature is 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, characterized in that: 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, characterized in that: The cemented prism and the lens (3) include three curved surfaces.

7. The optical module according to claim 6, characterized in that: 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, characterized in that: 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 vector 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, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: The third surface (S3) and the fourth surface (S4) are planes.

14. The optical module according to claim 9, characterized in that: 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, characterized in that: 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: Comprising the optical module as described in any one of claims 1-15.

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