Near-eye optical display system and intelligent head-mounted device

Abstract

The invention provides a near-eye optical display system and intelligent head-mounted equipment. The near-eye optical display system comprises a first lens, a second lens and a third lens which are sequentially arranged at intervals along an optical axis, wherein a light splitting element is arranged on the surface of one side, close to the first lens, of the second lens; a composite film material is arranged on the surface of the side, close to the first lens, of the third lens and comprises a first phase retarder and a polarization reflection element which are arranged in a stacked mode, and the first phase retarder is located on a light path between the light splitting element and the polarization reflection element. The near-eye optical display system further comprises a circularly polarized light generation assembly used for converting light in a specific polarization state into circularly polarized light, the circularly polarized light generation assembly is arranged on the side, away from the second lens, of the light splitting element, and a medium exists between the circularly polarized light generation assembly and the light splitting element. And the medium refractive index n2 between the circularly polarized light generation assembly and the light splitting element meets the condition that n2 is greater than or equal to 1.3.

Description

Technical Field

[0001] Embodiments of the present application relate to the technical field of optical display systems. More specifically, embodiments of the present application relate to a near-eye optical display system and an intelligent head-mounted device. Background Art

[0002] With the rapid development of virtual reality technology, high definition has become an important trend in the development of VR. However, the imaging quality and ghosting problems of the optical system have always been key factors affecting the user experience. Ghosting is usually caused by reflections between the lens surfaces. To reduce ghosting, traditional methods mostly use lens gluing, but this method will lose design variables and is not conducive to further optimizing the imaging quality.

[0003] Therefore, how to effectively reduce ghosting while ensuring the imaging quality has become an important challenge in the current design of VR optical systems. Summary of the Invention

[0004] The purpose of the present application is to provide a new technical solution for a near-eye optical display system and an intelligent head-mounted device.

[0005] In a first aspect, embodiments of the present application provide a near-eye optical display system. The near-eye optical display system includes a first lens, a second lens, and a third lens that are sequentially spaced along the optical axis. Among them: A beam splitting element is provided on a surface of the second lens close to the first lens. The beam splitting element is used for partially reflecting and partially transmitting incident light. A composite film material is provided on a surface of the third lens close to the first lens. The composite film material includes a first phase retarder and a polarization reflection element that are stacked, and the first phase retarder is located on the optical path between the beam splitting element and the polarization reflection element. The distance P between the second lens and the third lens satisfies 0.2 mm ≤ P ≤ 0.5 mm. The near-eye optical display system further includes a circularly polarized light generation component for converting light with a specific polarization state into circularly polarized light. The circularly polarized light generation component is provided on a side of the beam splitting element away from the second lens. There is a medium between the circularly polarized light generation component and the beam splitting element, and the refractive index n2 of the medium between the circularly polarized light generation component and the beam splitting element satisfies: n2 ≥ 1.3.

[0006] Optionally, the beam splitting element is a semi-transmissive and semi-reflective film layer, and the refractive indices n1 of the media in contact with both sides thereof satisfy: 1.3 ≤ n1 ≤ 1.8.

[0007] Optionally, the medium between the circularly polarized light generation component and the beam splitting element includes at least one of optical glue and a lens.

[0008] Optionally, the composite film material further includes a first polarization element, and the first polarization element is stacked on a surface of the polarization reflection element facing away from the first phase retarder.

[0009] Optionally, the circularly polarized light generating assembly includes a second phase retarder, a third phase retarder, and a second polarization element disposed between the second phase retarder and the third phase retarder.

[0010] Optionally, the surface of the second lens facing away from the first lens is a concave surface, and the radius of curvature ranges from -60 mm to -40 mm.

[0011] Optionally, the optical power φ1 of the first lens satisfies 0.014 ≤ φ1 ≤ 0.016; The optical power φ2 of the second lens satisfies 0.007 ≤ φ2 ≤ 0.008; The optical power φ3 of the third lens satisfies -0.02 ≤ φ3 ≤ -0.001.

[0012] Optionally, the near-eye optical display system further includes a display screen, the display screen is located on a side of the first lens facing away from the second lens, and the air gap B between the display screen and the first lens satisfies: 0.4 mm ≤ B ≤ 0.7 mm.

[0013] Optionally, the ratio of the maximum effective optical diameter Dmax of the lens in the near-eye optical display system to the optical total length TTL of the near-eye optical display system satisfies: 2.5 ≤ Dmax / TTL ≤ 3.

[0014] Optionally, the optical total length TTL of the near-eye optical display system satisfies: 15 mm ≤ TTL ≤ 17 mm.

[0015] Optionally, the number n of lenses between the circularly polarized light generating assembly and the display screen satisfies n ≥ 1.

[0016] In a second aspect, an embodiment of the present application provides an intelligent head-mounted device, and the intelligent head-mounted device includes: A housing; and The near-eye optical display system as described in the first aspect.

[0017] The beneficial effects of the present application are as follows: The near-eye optical display system provided by the embodiment of the present application proposes an effective solution to the technical problem of difficult to balance high imaging quality and low ghosting in the field of VR imaging display, and achieves the dual optimization goals of image quality improvement and ghosting suppression.

[0018] Specifically, in the present application, by designing the refractive index n2 of the medium between the beam splitting element and the circularly polarized light generating component to be n2≥1.3, an optical refractive index difference of at least 0.3 can be formed between this medium and air (refractive index n≈1). This design in the present application can significantly reduce the reflected light energy of the key optical interfaces on the optical path between the beam splitting element and the circularly polarized light generating component. According to experimental data, the reduction in the reflected light energy can exceed 50%, thereby effectively suppressing the generation of the "ghost image" phenomenon, greatly improving the purity and visual clarity of the image, and being able to bring a clear visual experience to users. Moreover, in the optical architecture design of the present application, a non-glued optical path design is adopted, and each lens is independent of each other, which abandons the aberration problem introduced by the glue layer between the lenses in the traditional solution. For example, each lens in the present application is independently arranged. In particular, there is a certain interval between the second lens and the third lens. The advantage of this design compared to gluing is that there is one more degree of freedom for the aspherical surface, which is beneficial to the correction of aberration and the improvement of image quality.

[0019] Other features and advantages of the present specification will become clear through the following detailed description of the exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings incorporated in and constituting a part of this specification illustrate embodiments of the present specification and, together with the description, are used to explain the principles of the present specification.

[0021] Figure 1 One of the schematic structural diagrams of the near-eye optical display system provided by the embodiment of the present application; Figure 2 The schematic diagram of the composite film material of the near-eye optical display system provided by the embodiment of the present application; Figure 3 Is Figure 1 The dot array diagram of the near-eye optical display system shown; Figure 4 Is Figure 1 The MTF diagram of the near-eye optical display system shown; Figure 5 Is Figure 1 The field curvature and optical distortion diagram of the near-eye optical display system shown; Figure 6 Is Figure 1 The vertical chromatic aberration diagram of the near-eye optical display system shown; Figure 7 Another schematic structural diagram of the near-eye optical display system provided by the embodiment of the present application; Figure 8 Is Figure 7 The dot array diagram of the near-eye optical display system shown; Figure 9 Is Figure 7MTF diagram of the near-eye optical display system shown; Figure 10 is Figure 7 Field curvature and optical distortion diagram of the near-eye optical display system shown; Figure 11 is Figure 7 Axial chromatic aberration diagram of the near-eye optical display system shown; Figure 12 Figure 3 is a schematic structural diagram of the near-eye optical display system provided by an embodiment of the present application; Figure 13 is Figure 12 Dot array diagram of the near-eye optical display system shown; Figure 14 is Figure 12 MTF diagram of the near-eye optical display system shown; Figure 15 is Figure 12 Field curvature and optical distortion diagram of the near-eye optical display system shown; Figure 16 is Figure 12 Axial chromatic aberration diagram of the near-eye optical display system shown; Figure 17 is the ghost energy distribution of the conventional optical path; Figure 18 is the ghost energy distribution of the near-eye optical display system provided by an embodiment of the present application.

[0022] Description of reference numerals: 1. Display screen; 2. First lens; 21. First surface; 22. Second surface; 3. Second lens; 31. Third surface; 32. Fourth surface; 311. Beam splitter element; 4. Third lens; 41. Fifth surface; 411. Anti-reflection film; 412. Polarizing element; 413. Polarizing reflection element; 414. Phase retarder; 42. Sixth surface; 5. Circularly polarized light generating assembly; 01. Human eye. Detailed Description of the Embodiment

[0023] Now, various exemplary embodiments of the present application will 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.

[0024] 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 or its application or use.

[0025] Technologies and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies and devices should be regarded as part of the specification.

[0026] In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments may have different values.

[0027] It should be noted that like reference numerals and letters denote like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

[0028] The near-eye optical display system and the intelligent head-mounted device provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0029] According to an embodiment of the present application, a near-eye optical display system is provided. Refer to Figure 1 and Figure 2 , the near-eye optical display system includes a first lens 2, a second lens 3, and a third lens 4 that are sequentially and spaced apart along the optical axis. Among them: a beam splitting element 311 is provided on one surface of the second lens 3 close to the first lens 2, and the beam splitting element 311 is used for partially reflecting and partially transmitting incident light; a composite film material is provided on one surface of the third lens 4 close to the first lens 2, and the composite film material includes a first phase retarder 414 and a polarization reflection element 413 that are stacked, and the first phase retarder 414 is located on the optical path between the beam splitting element 311 and the polarization reflection element 413. The distance P between the second lens 3 and the third lens 4 is 0.2 mm ≤ P ≤ 0.5 mm; the near-eye optical display system further includes a circularly polarized light generating component 5 for converting light of a specific polarization state into circularly polarized light. The circularly polarized light generating component 5 is provided on the side of the beam splitting element 311 away from the second lens 3. There is a medium between the circularly polarized light generating component 5 and the beam splitting element 311, and the refractive index n2 of the medium between the circularly polarized light generating component 5 and the beam splitting element 311 satisfies: n2 ≥ 1.3.

[0030] The near-eye optical display system provided by the embodiments of the present application has broad expandability in the application field, and is particularly suitable for the VR (virtual reality) optical display field. Thanks to its unique optical design and excellent optical performance, the near-eye optical display system provided by the embodiments of the present application also has the potential to be applied in other near-eye optical display fields such as AR (augmented reality).

[0031] Aiming at the problem that it is difficult to balance high imaging quality and low ghosting in the prior art, the embodiments of the present application propose a new design of a near-eye optical display system, which will be elaborated in detail below.

[0032] The near-eye optical display system provided by the embodiments of the present application. Refer toFigure 1 , which includes three lenses: a first lens 2, a second lens 3, and a third lens 4. As can be observed from the Figure 1 optical layout shown in, these three lenses are not bonded in the traditional way, but are each independently arranged and there is a certain air gap (such as 0.3 mm to 0.4 mm) between each pair. This non-bonded design effectively avoids the aberration problems that may be introduced by the bonding layer.

[0033] Optionally, the near-eye optical display system provided by the embodiments of the present application includes, but is not limited to, three lenses, and may also be two lenses or other numbers of lenses.

[0034] For example, when the near-eye optical display system of the present application includes only two lenses, the third lens 4 on the side close to the human eye 01 can be cancelled.

[0035] For example, when the near-eye optical display system of the present application includes four lenses, a lens can be provided between the beam splitting element 311 and the circularly polarized light generating component 5.

[0036] The following will describe in detail each optical element in the near-eye optical display system provided by the embodiments of the present application.

[0037] First lens 2: As the starting lens element of the near-eye optical display system provided by the embodiments of the present application, the first lens 2 plays the role of guiding and adjusting the imaging display light emitted from the display screen 1. It ensures that the light can enter the subsequent optical path at an appropriate angle and direction, laying the foundation for the optical performance of the entire near-eye optical display system.

[0038] Second lens 3, beam splitting element 311, and circularly polarized light generating component 5: The second lens 3 is located on the side of the first lens 2 away from the display screen 1, and the beam splitting element 311 and the circularly polarized light generating component 5 are provided on the surface of the second lens 3 close to the first lens 2.

[0039] Specifically, referring to Figure 1 , the beam splitting element 311 is provided on the surface of the second lens 3 close to the first lens 2 (i.e., the third surface 31). The beam splitting element 311 is, for example, a semi-transmissive and semi-reflective film layer. In the embodiments of the present application, the main function of the beam splitting element 311 is to partially reflect and partially transmit the incident light, and this characteristic is crucial for realizing the optical path control of the optical display system. Further, on the side of the beam splitting element 311 away from the second lens 3, the circularly polarized light generating component 5 is further introduced. The circularly polarized light generating component 5 is mainly used to convert light with a specific polarization state into circularly polarized light. The circularly polarized light generating component 5 and the beam splitting element 311 can work together to jointly optimize the optical performance of the optical display system.

[0040] There is a medium between the beam splitting element 311 and the circularly polarized light generating assembly 5. This medium is, for example, an optical adhesive, such as OCA adhesive or UV adhesive.

[0041] Of course, one or more lenses with a specific refractive index can also be provided between the beam splitting element 311 and the circularly polarized light generating assembly 5.

[0042] The third lens 4, the first phase retarder 414, and the polarization reflection element 413: The third lens 4, as the last lens element in the optical path, is responsible for further adjusting and focusing the light rays processed by the first two lenses (i.e., the first lens 2 and the second lens 3), ensuring that these light rays can enter the human eye 01 and finally form a clear visual image.

[0043] The first phase retarder 414, which is, for example, a quarter-wave plate, is mainly used to perform phase retardation on light rays, thereby changing the polarization state of the light rays. The polarization reflection element 413, which is, for example, a polarization reflection film, can reflect or transmit according to the polarization state of the light rays. In the near-eye optical display system provided in the embodiments of the present application, the polarization reflection element 413 and the first phase retarder 414 work together to ensure that only light rays with a specific polarization state can be effectively utilized, which is beneficial to improving the clarity and purity of the picture.

[0044] The polarization reflection element 413, the first phase retarder 414, and the beam splitting element 311 can also cooperate with each other to form a folded optical path.

[0045] In the near-eye optical display system provided in the embodiments of the present application, the design of the refractive index n2 of the medium is a key technical point, which refers to the design of the refractive index of the medium existing between the circularly polarized light generating assembly 5 and the beam splitting element 311. The following is an analysis of the design of the refractive index n2 of this medium.

[0046] In the present application, by controlling the refractive index n2 of the medium between the beam splitting element 311 and the circularly polarized light generating assembly 5 to meet the optical parameter design requirement of n2≥1.3, it is ensured that there is a significant difference (for example, at least a refractive index difference of 0.3) between the refractive index of this medium n2 and the refractive index of air (n≈1). This refractive index difference can be used to reduce the reflectivity of the key optical interfaces on the optical path between the beam splitting element 311 and the circularly polarized light generating assembly 5, thereby effectively reducing the generation of reflected light rays. Due to the reduction of reflected light rays, the "ghosting" phenomenon is effectively suppressed, because ghosting is usually caused by the reflection between the lens surfaces. Through this optical parameter design in the present application, the purity and visual clarity of the finally formed image are greatly improved.

[0047] In the present application, the spacing P between the second lens 3 and the third lens 4 is such that 0.2 mm ≤ P ≤ 0.5 mm. That is to say, a certain air gap is maintained between these two lenses. The advantage compared to traditional glued lenses is that there is an additional degree of freedom for aspheric surfaces, which is beneficial for correcting aberrations and improving image quality.

[0048] Optionally, the spacing P between the second lens 3 and the third lens 4 is 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm.

[0049] It should be noted that the interval P between the second lens 3 and the third lens 4 refers to the air gap between these two lenses in the optical axis direction.

[0050] In addition, the design of the medium refractive index n2 in the present application not only focuses on ghost suppression but also fully considers the optimization of the overall optical performance. For example, by adopting a non-glued optical path design, the independence and better optical performance among the first lens 2, the second lens 3, the third lens 4, etc. are ensured, and the aberration problems that may be introduced in the traditional gluing scheme are avoided. This design enables each lens to fully exert its optical characteristics, thereby further improving the overall imaging quality.

[0051] In summary, the design of the medium refractive index n2 in the embodiments of the present application is a key design point in the near-eye optical display system. By optimizing the selection of the medium refractive index between the beam splitter element 311 and the circularly polarized light generating component 5, the dual goals of ghost suppression and imaging quality improvement are achieved, providing users with a clearer and purer visual experience.

[0052] In some examples of the present application, the beam splitter element 311 is a semi-transmissive and semi-reflective film layer, and the refractive index n1 of the media in contact with its two sides satisfies: 1.3 ≤ n1 ≤ 1.8.

[0053] In this example provided by the present application, the beam splitter element 311 is a semi-transmissive and semi-reflective film layer, and the refractive index of the media in contact with its two sides is set as n1, and this n1 is designed within the range of 1.3 to 1.8. This design of optical parameters forms a collaborative optimization with the requirement that the refractive index n2 ≥ 1.4 of the medium between the aforementioned circularly polarized light generating component 5 and the beam splitter element 311, and at the same time brings the following significant technical effects: By maintaining a reasonable refractive index of the media on both sides of the beam splitter element 311, the stability of light propagation within the near-eye optical display system is ensured. It should be noted that refer to Figure 1The left side of the spectroscopic element 311 is the second lens 3, and the right side of the spectroscopic element 311 is the medium between the spectroscopic element 311 and the circularly polarized light generating component 5. On this basis, the refractive index of the second lens 3 and the medium can be controlled within the above-mentioned range of 1.3~1.8.

[0054] The optical design in this example significantly reduces the reflectivity of the interfaces on both sides of the beam splitter element 311. This reduction in reflectivity lays the foundation for reducing ghosting, as ghosting is often caused by reflections between lens surfaces. Combined with the application of the circularly polarized light generating assembly 5, the total ghosting energy of the near-eye optical display system provided in this embodiment of the application is further reduced, providing users with a clearer and purer visual experience.

[0055] The refractive index range of 1.3 to 1.8 ensures a sufficient refractive index difference to achieve effective ghost suppression while avoiding the problem of increased dispersion of optical materials that may be caused by an excessively high refractive index.

[0056] This example of the present application achieves efficient synergistic optimization with the overall optical design of the optical display system by controlling the refractive index parameters on both sides of the beam splitter element 311. While maintaining optical performance, the optical design in this example takes ghost suppression to a new level. For example, ghost visibility is reduced to a level that is almost imperceptible to the human eye, providing users with an excellent visual experience.

[0057] In summary, the present application optimizes the light propagation path by controlling the refractive index parameters on both sides of the spectroscopic element 311, effectively reduces the ghosting phenomenon, improves the clarity and purity of the picture, and brings users a better visual experience.

[0058] In some examples of the present application, the medium between the circularly polarized light generating component 5 and the light splitting element 311 includes at least one of optical glue and a lens.

[0059] As media, optical adhesives and lenses themselves have certain optical properties, such as refractive index and transmittance. By selecting appropriate media materials and parameters, the imaging quality of the optical display system can be further optimized.

[0060] When optical glue is selected as the medium, the circularly polarized light generating assembly 5 and the light splitting element 311 can be bonded together to form a stable optical whole. The optical glue is, for example, OCA glue or UV glue.

[0061] In some cases, lenses can also be used as the medium. This choice can achieve specific optical functions, such as focusing, etc. By rationally designing the shape and parameters of the lens, the performance of the optical system can be further optimized to meet specific application requirements.

[0062] It should be noted that using the optical adhesive and the lens as the medium between the beam splitting element 311 and the circularly polarized light generating assembly 5 can meet the refractive index n2 requirement set in this application. Specifically, by selecting the type of the optical adhesive and the material of the lens, the refractive index of this region can be adjusted to ensure that when light travels between the beam splitting element 311 and the circularly polarized light generating assembly 5, it can follow the designed optical path, effectively reducing light scattering and reflection, thereby optimizing the imaging quality and ghosting suppression effect of the entire near-eye optical display system.

[0063] In some examples of this application, referring to Figure 1 and Figure 2 , the composite film material further includes a first polarization element 412, and the first polarization element 412 is stacked on a surface of the polarization reflection element 413 facing away from the first phase retarder 414.

[0064] A polarization element (i.e., a polarization film) is an optical element that can filter out light with a specific polarization direction. In the composite film material of this application, the first polarization element 412 can be used to further purify the light reflected by the polarization reflection element 413 to ensure that only light with a specific polarization direction can continue to propagate.

[0065] In the design of this application, the first phase retarder 414, the polarization reflection element 413, and the first polarization element 412 are integrated together to form a stacked structure. Among them, the first phase retarder 414 converts incident light into light with a specific polarization direction, the polarization reflection element 413 selectively reflects the light with this polarization direction, and the first polarization element 412 further purifies the reflected light, reducing light loss and improving the overall light utilization efficiency.

[0066] In addition, integrating the first phase retarder 414, the polarization reflection element 413, and the first polarization element 412 together to form a stacked structure can also simplify the optical design.

[0067] Optionally, the composite film material further includes an antireflection film 411, referring to Figure 2 .

[0068] An antireflection film is an optical thin film coated on the surface of an optical element to reduce light reflection and increase light transmittance. It improves the light transmission efficiency by reducing the reflection caused by the refractive index difference when light travels from one medium to another.

[0069] In the composite film material provided by the present application, the anti-reflection film 411 can effectively reduce the reflection loss of light on the surface of the optical element (such as the third lens 4). The application of the anti-reflection film 411 can significantly improve the light transmittance, enabling more light to propagate along the designed path and ultimately enter the human eye 01, thereby improving the imaging brightness and contrast.

[0070] The reduction of the reflected light not only improves the light transmittance but also helps to reduce the generation of glare and stray light. Glare and stray light will reduce the clarity and contrast of the image, affecting the user's visual experience. The application of the anti-reflection film 411 can effectively suppress the generation of these adverse lights and improve the purity and quality of the image.

[0071] The anti-reflection film 411 can also serve as a protective layer, providing an additional layer of protection for the optical element and extending its service life.

[0072] In some examples of the present application, referring to Figure 1 , the circularly polarized light generating component 5 includes a second phase retarder, a third phase retarder, and a second polarization element disposed between the second phase retarder and the third phase retarder.

[0073] The circularly polarized light generating component 5 is mainly composed of a second phase retarder, a second polarization element, and a third phase retarder stacked in sequence, and is integrally integrated with the beam splitting element 311 on the surface of the second lens 3 close to the first lens 2 (referring to Figure 1 the third surface 31 in ).

[0074] The circularly polarized light generating component 5 provided in the present application realizes precise phase retardation and polarization state selection of light through the combination of a double phase retarder and a polarization element. This design not only improves the generation efficiency and quality of circularly polarized light but also can reduce the generation of ghosting phenomena, bringing a clearer and purer visual experience to the near-eye optical display system.

[0075] Stray light and ghosting are common problems in near-eye optical systems, which will reduce the clarity and contrast of the image. The circularly polarized light generating component 5 formed in this example of the present application effectively reduces the generation of stray light and ghosting by selectively reflecting and transmitting light with a specific polarization direction, thereby improving the purity and clarity of the image.

[0076] In some examples of the present application, referring to Figure 1 , the surface of the second lens 3 facing away from the first lens 2 is a concave surface, and the range of its radius of curvature is -60 mm to -40 mm.

[0077] As the key refracting surface of the near-eye optical display system, this concave surface effectively compensates for the astigmatism introduced by the front surface beam splitter 311 first, thus improving the overall imaging clarity. At the same time, this concave surface works in cooperation with the first lens 2 to jointly correct the field curvature of the near-eye optical display system, ensuring the uniformity of the image across the entire field of view. In addition, by precisely controlling the radius of curvature of the concave surface, the distortion control of the near-eye optical display system can be reduced to provide a more realistic and distortion-free visual experience.

[0078] The combination of the radius of curvature of this concave surface and the refractive index design (n2≥1.4) achieves effective deflection of stray light, guiding it to the non-imaging area, thereby reducing the interference of stray light on the imaging quality.

[0079] At the same time, this design of this example in the present application also significantly reduces the surface reflectivity, further improving the contrast and purity of the image, bringing a clearer visual effect to the user.

[0080] In some examples of the present application, the optical power φ1 of the first lens 2 is 0.014≤φ1≤0.016; the optical power φ2 of the second lens 3 is 0.007≤φ2≤0.008; the optical power φ3 of the third lens 4 is -0.02≤φ3≤-0.001.

[0081] In the example of the present application, the three lenses of the near-eye optical display system adopt a specific optical power configuration. Specifically, the optical power φ1 of the first lens 2 is positive and is designed to be in the range of 0.014 to 0.016; the optical power φ2 of the second lens 3 is also positive and is designed to be in the range of 0.007 to 0.008; the optical power φ3 of the third lens 4 is designed to be negative, and its optical power range is between -0.02 and -0.001. This distribution of optical power is based on a comprehensive consideration of the imaging quality, ghosting suppression, and overall performance optimization of the entire near-eye optical display system.

[0082] By reasonably distributing the optical powers of these three lenses, the near-eye optical display system of the present application can more effectively control the propagation path and polarization state of light, thereby reducing the reflection of light on the lens surface. Especially when the first lens 2 and the second lens 3 maintain positive optical powers, while the third lens 4 has a negative optical power, this configuration helps to form a more reasonable optical path structure, enabling light to propagate more smoothly when passing through the lens group, and thus reducing the surface reflectivity.

[0083] Specific optical power configurations help correct aberrations in optical systems, such as spherical aberration and coma, thereby improving image clarity and contrast. In this application, the positive optical power design of the first lens 2 and the second lens 3 enables them to better focus light, while the negative optical power of the third lens 4 helps correct aberrations that may be introduced by the first two lenses, jointly achieving high-quality imaging effects.

[0084] Ghosting is often associated with light reflection and scattering within an optical system. By optimizing the focal power configuration of the three lenses, we can reduce light reflection on lens surfaces, particularly Fresnel reflection at key interfaces like the beam splitter, effectively suppressing ghosting.

[0085] In addition, a reasonable optical power configuration not only helps improve image quality and ghost suppression, but also optimizes the overall performance of the system, including improving the system's light energy utilization, reducing the system's size and weight, and enhancing the system's stability and reliability.

[0086] In some examples of this application, see Figure 1 The near-eye optical display system also includes a display screen 1, which is located on the side of the first lens 2 away from the second lens 3, and the air gap B between the display screen 1 and the first lens 2 satisfies: 0.4mm≤B≤0.7mm.

[0087] In the example provided in this application, the optical design of the near-eye optical display system also focuses on the size of the air gap B between the display screen 1 and the first lens 2, and designs it within the range of 0.4 mm to 0.7 mm.

[0088] Proper setting of air gap B helps correct aberrations of near-eye optical display systems, such as field curvature and distortion. When air gap B is within the range of 0.4mm to 0.7mm, it can better match the overall design of the near-eye optical display system, making imaging more accurate and clear, and reducing image distortion and blur.

[0089] An appropriate air gap B can reduce reflection and scattering of light at the interface between the display screen 1 and the first lens 2, thereby reducing ghosting and stray light. This is crucial for improving the user experience, as ghosting and stray light can interfere with the user's visual experience and reduce image contrast and clarity.

[0090] In addition, reasonable control of the air gap B can also control the size of the near-eye optical display system.

[0091] In some examples of the present application, the ratio of the maximum effective optical diameter Dmax of the lens in the near-eye optical display system to the total optical length TTL of the near-eye optical display system satisfies: 2.5 ≤ Dmax / TTL ≤ 3.

[0092] When the ratio of Dmax / TTL is in the range of 2.5 to 3, the lens in the near-eye optical display system can effectively capture and focus the light from the display screen 1, reducing the loss and scattering of light, thereby improving the clarity and contrast of the image. Moreover, this reasonable ratio design helps to correct the aberrations of the near-eye optical display system, such as spherical aberration, coma aberration, etc., further improving the imaging quality.

[0093] In addition, by controlling the ratio of Dmax to TTL, the overall length of the near-eye optical display system can be reduced on the premise of ensuring optical performance, realizing a compact design of the system. The compact design of the near-eye optical display system helps to reduce the volume and weight of the device, improving the wearing comfort of users.

[0094] In some examples of the present application, the total optical length TTL of the near-eye optical display system satisfies: 15 mm ≤ TTL ≤ 17 mm.

[0095] Controlling TTL within the range of 15 mm to 17 mm helps to reduce the overall length of the system, realizing a compact design of the system. The compact system design not only reduces the volume and weight of the device, but also improves the wearing comfort and portability of users.

[0096] In some examples of the present application, the number of lenses n between the circularly polarized light generating component 5 and the display screen 1 satisfies n ≥ 1.

[0097] In an optical system, aberration is one of the key factors affecting imaging quality. In the near-eye optical display system provided by the embodiments of the present application, by setting at least one lens between the circularly polarized light generating component 5 and the display screen 1, the aberrations generated during the transmission of light, such as spherical aberration, coma aberration, astigmatism, etc., can be effectively corrected and compensated. This correction effect makes the image finally projected onto the display screen 1 clearer, greatly improving the overall image quality.

[0098] The addition of the lens not only changes the propagation path of the light, but also focuses and shapes the light through its specific optical properties (such as curvature, refractive index, etc.). This optimized design helps to reduce the loss of light during transmission and improve the utilization rate of light energy.

[0099] The near-eye optical display system design provided by the embodiments of the present application includes three lenses: the first lens 2, the second lens 3, and the third lens 4. The refractive index n and dispersion coefficient v of these three lenses are in the range of: 1.4 < n < 2.0, 20 < v < 75.

[0100] The optical path design of the near-eye optical display system provided by the embodiments of the present application is carefully optimized to achieve high-quality imaging effects and ghosting suppression. The specific optical path is described as follows. Refer to Figure 1 : The light emitted by the display screen 1 first passes through the protective glass on its surface for transmission, and then the light passes through the first lens 2 and the second lens 3 in sequence. Next, the light reaches the fifth surface 41 of the third lens 4 and is reflected, and then is reflected again by the third surface 31 of the second lens 3. After that, the light processed by the second lens 3 continues to propagate, passes through the third lens 4 for transmission, and finally enters the human eye 01, so that the user can clearly observe the image.

[0101] Among them, when the light emitted from the display screen 1 encounters the circularly polarized light generating component 5 on the third surface 31 of the second lens 3, it will become circularly polarized light.

[0102] In the above process, an antireflection film layer can be coated on the sixth surface 42 of the third lens 4 to reduce the loss of light during transmission. Finally, a clear image is formed at the human eye 01. At the same time, due to the optimization of the optical path design, the ghosting phenomenon is effectively suppressed.

[0103] The near-eye optical display system provided by the embodiments of the present application has achieved remarkable results in ghosting suppression. For specific effects, please refer to Figure 17 and Figure 18 the comparison diagram of the ghost energy distribution shown.

[0104] Figure 17 shows the ghost energy distribution under the conventional optical path. It can be clearly observed from Figure 17 that there are obvious circular high-energy ghost regions (such as the circled regions on the outside in Figure 17 ). The peak intensity of these ghosts is as high as 8% to 12% of the main image brightness, and the energy distribution range is wide, occupying 35% to 40% of the field of view area. Such a ghosting phenomenon seriously affects the user's visual experience and reduces the clarity and purity of the image.

[0105] Figure 18 shows the ghost energy distribution diagram of the near-eye optical display system of the present application. Compared with the conventional optical path, the system of the present application almost completely eliminates the circular ghosting phenomenon, and the ghost energy is reduced to an invisible level. The remaining ghost intensity is less than 0.5% of the main image brightness, and the energy distribution is more concentrated, only accounting for 5% to 8% of the field of view area. This improvement means that the ghost energy is significantly reduced, and the ghost contrast is strictly controlled below the threshold that is difficult for the human eye to detect.

[0106] The near-eye optical display system of the present application will be described below through Embodiment 1 to Embodiment 3 respectively.

[0107] Embodiment 1 The near-eye optical display system provided in this Embodiment 1 is shown in Figure 3 , and includes a display screen 1, a first lens 2, a circularly polarized light generating component 5, a beam splitting element 311, a second lens 3, a composite film material, and a third lens 4 that are sequentially arranged along the same optical axis. An OCA adhesive is provided between the circularly polarized light generating component 5 and the beam splitting element 311, and the refractive index of this OCA adhesive is 1.54, that is, the refractive index n2 of the medium in this Embodiment 1 is 1.54; Among them, the display screen 1 is used to provide light for imaging display, and a protective glass is provided on the light emitting surface of the display screen 1; The first lens 2 includes a first surface 21 (close to the display screen 1) and a second surface 22 (away from the display screen 1); the optical power φ1 of the first lens 2 is designed to be 0.015; The second lens 3 includes a third surface 31 close to the first lens 2 and a fourth surface 32 away from the first lens 2. The beam splitting element 311 and the circularly polarized light generating component 5 are provided on the third surface 31; the optical power φ2 of the second lens 3 is designed to be 0.0075; The third lens 4 includes a fifth surface 41 and a sixth surface 42, and the composite film material is provided on the fifth surface 41; the optical power φ3 of the third lens 4 is designed to be -0.018; The interval P between the second lens 3 and the third lens 4 is 0.3 mm; As shown in Figure 2 , the composite film material includes a first phase retarder 414, a polarization reflection element 4, a first polarization element 412, and an anti-reflection film 411 that are sequentially arranged on the fifth surface 41 along the optical axis, and the first phase retarder 414 is located on the optical path between the beam splitting element 311 and the polarization reflection element 413; The circularly polarized light generating component 5 includes a second phase retarder, a third phase retarder, and a second polarization element provided between the second phase retarder and the third phase retarder.

[0108] The optical parameters of the near-eye optical display system provided in this Embodiment 1 are shown in Table 1 below.

[0109] Table 1

[0110] The optical performance of the near-eye optical display system provided in this Embodiment 1 is as shown in Figures 3 to 6 : Figure 3It is a schematic diagram of a spot diagram. Figure 4 It is an MTF curve graph. Figure 5 It is a field curvature and distortion graph. Figure 6 It is a lateral chromatic aberration graph.

[0111] A spot diagram refers to a dispersion pattern formed by many rays emitted from a point after passing through a near-eye optical display system. Due to aberration, the intersection points of these rays with the image plane are no longer concentrated at the same point but are scattered within a certain range, which is used to evaluate the imaging quality of the projection near-eye optical display system. See Figure 3 , for the near-eye optical display system provided in Embodiment 1, the maximum value of the image points in the spot diagram is less than 71 μm.

[0112] An MTF curve graph is a modulation transfer function graph, which characterizes the imaging sharpness of a near-eye optical display system through the contrast of black and white line pairs. See Figure 4 , for the near-eye optical display system provided in Embodiment 1, MTF > 0.4 at 20 lp / mm See Figure 5 , for the near-eye optical display system provided in Embodiment 1, the maximum distortion occurs at a 1° field of view, and its absolute value is less than 46%.

[0113] Lateral chromatic aberration is also called magnification chromatic aberration. It mainly refers to the difference in the focal positions of blue and red light on the image plane when a principal polychromatic ray in the object space becomes multiple rays when exiting the refraction system due to dispersion. See Figure 6 , for the near-eye optical display system provided in Embodiment 1, its maximum chromatic aberration value is less than 300 μm.

[0114] Embodiment 2 The near-eye optical display system provided in Embodiment 2, see Figure 7 , includes a display screen 1, a first lens 2, a circularly polarized light generating component 5, a beam splitting element 311, a second lens 3, a composite film material, and a third lens 4 arranged in sequence along the same optical axis. And a UV glue is provided between the circularly polarized light generating component 5 and the beam splitting element 311, and the refractive index of this UV glue is 1.6, that is, the refractive index n2 of the medium in Embodiment 2 is 1.6; Among them, the display screen 1 is used to provide light for imaging display, and a protective glass is provided on the light-emitting surface of the display screen 1; The first lens 2 includes a first surface 21 (close to the display screen 1) and a second surface 22 (away from the display screen 1); the optical power φ1 of the first lens 2 is designed to be 0.016; The second lens 3 includes a third surface 31 close to the first lens 2 and a fourth surface 32 away from the first lens 2. The beam splitting element 311 and the circularly polarized light generating component 5 are provided on the third surface 31; the optical power φ2 of the second lens 3 is designed to be 0.0072; The third lens 4 includes a fifth surface 41 and a sixth surface 42, and the composite film material is disposed on the fifth surface 41; the optical power φ3 of the third lens 4 is designed to be -0.004; The interval P between the second lens 3 and the third lens 4 is 0.2 mm; See Figure 2 , the composite film material includes a first phase retarder 414, a polarization reflection element 413, a first polarization element 412, and an antireflection film 411 that are sequentially disposed on the fifth surface 41 along the optical axis, and the first phase retarder 414 is located on the optical path between the beam splitting element 311 and the polarization reflection element 413; The circularly polarized light generating assembly 5 includes a second phase retarder, a third phase retarder, and a second polarization element disposed between the second phase retarder and the third phase retarder.

[0115] The optical parameters of the near-eye optical display system provided in Embodiment 2 are shown in Table 2 below.

[0116] Table 2

[0117] The near-eye optical display system provided in Embodiment 2 has optical performance as Figures 8 to 11 shown: Figure 8 is a spot diagram schematic, Figure 9 is an MTF curve graph, Figure 10 is a field curvature and distortion graph, Figure 11 is a lateral chromatic aberration graph.

[0118] See Figure 8 , for the near-eye optical display system provided in Embodiment 2, the maximum value of the image points in the spot diagram is less than 26 μm.

[0119] See Figure 9 , for the near-eye optical display system provided in Embodiment 2, the MTF is >0.4 at 20 lp / mm.

[0120] See Figure 10 , for the near-eye optical display system provided in Embodiment 2, the maximum distortion occurs at 1 field of view, and the absolute value is less than 46%.

[0121] See Figure 11 , for the near-eye optical display system provided in Embodiment 2, the maximum chromatic aberration value is less than 300 μm.

[0122] Embodiment 3 For the near-eye optical display system provided in Embodiment 3, see Figure 12, including a display screen 1, a first lens 2, a circularly polarized light generating component 5, a beam splitting element 311, a second lens 3, a composite film material, and a third lens 4 arranged in sequence along the same optical axis. A UV glue is provided between the circularly polarized light generating component 5 and the beam splitting element 311, and the refractive index of the UV glue is 1.7, that is, the refractive index n2 of the medium in this Embodiment 2 is 1.7; Among them, the display screen 1 is used to provide light for imaging display, and a protective glass is provided on the light emitting surface of the display screen 1; The first lens 2 includes a first surface 21 (close to the display screen 1) and a second surface 22 (away from the display screen 1); the optical power φ1 of the first lens 2 is designed to be 0.014; The second lens 3 includes a third surface 31 close to the first lens 2 and a fourth surface 32 away from the first lens 2. The beam splitting element 311 and the circularly polarized light generating component 5 are provided on the third surface 31; the optical power φ2 of the second lens 3 is designed to be 0.0077; The third lens 4 includes a fifth surface 41 and a sixth surface 42, and the composite film material is provided on the fifth surface 41; the optical power φ3 of the third lens 4 is designed to be -0.0017; The interval P between the second lens 3 and the third lens 4 is 0.4 mm; See Figure 2 , the composite film material includes a first phase retarder 414, a polarization reflection element 413, a first polarization element 412, and an anti-reflection film 411 arranged in sequence along the optical axis on the fifth surface 41, and the first phase retarder 414 is located on the optical path between the beam splitting element 311 and the polarization reflection element 413; The circularly polarized light generating component 5 includes a second phase retarder, a third phase retarder, and a second polarization element provided between the second phase retarder and the third phase retarder.

[0123] The optical parameters of the near-eye optical display system provided in this Embodiment 3 are shown in Table 3 below.

[0124] Table 3

[0125] The near-eye optical display system provided in this Embodiment 3 has optical performance as Figures 13 to 16 shown: Figure 13 is a spot diagram schematic diagram, Figure 14 is an MTF curve graph, Figure 15 is a field curvature and distortion graph, Figure 16 is a lateral chromatic aberration graph.

[0126] See Figure 13, for the near-eye optical display system provided in Embodiment 3 of the present invention, the maximum value of the image points in the spot diagram is less than 20 μm.

[0127] See Figure 14 , for the near-eye optical display system provided in Embodiment 3 of the present invention, the MTF is > 0.4 at 20 lp / mm.

[0128] See Figure 15 , for the near-eye optical display system provided in Embodiment 3 of the present invention, the maximum distortion occurs at 1 field of view, and the absolute value is less than 46%.

[0129] See Figure 16 , for the near-eye optical display system provided in Embodiment 3 of the present invention, the maximum chromatic aberration is less than 300 μm.

[0130] According to another embodiment of the present application, an intelligent head-mounted device is provided. The intelligent head-mounted device includes a housing and the near-eye optical display system as described above. The near-eye optical display system is disposed in the housing.

[0131] The intelligent head-mounted device provided in the embodiments of the present application is, for example, a VR head-mounted display device.

[0132] The specific implementation manners of the intelligent head-mounted device in the embodiments of the present application may refer to the respective embodiments of the above-mentioned near-eye optical display system. Therefore, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated herein one by one.

[0133] What was mainly described in the above embodiments is 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 more optimal embodiment. Considering the simplicity of the writing, it will not be elaborated herein.

[0134] Although some specific embodiments of the present application have been described in detail by way of examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present application. Those skilled in the art should understand that the above embodiments can 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. A near-eye optical display system, characterized in that, It includes a first lens (2), a second lens (3), and a third lens (4) that are sequentially arranged at intervals along the optical axis, where: On one side surface of the second lens (3) close to the first lens (2), there is a beam-splitting element (311), and the beam-splitting element (311) is used for partially reflecting and partially transmitting incident light; On one side surface of the third lens (4) close to the first lens (2), there is a composite film material, and the composite film material includes a first phase retarder (414) and a polarization reflection element (413) that are stacked, and the first phase retarder (414) is located on the optical path between the beam-splitting element (311) and the polarization reflection element (413); The distance P between the second lens (3) and the third lens (4) satisfies: 0.2 mm ≤ P ≤ 0.5 mm; The near-eye optical display system further includes a circularly polarized light generating component (5) for converting light of a specific polarization state into circularly polarized light. The circularly polarized light generating component (5) is arranged on the side of the beam-splitting element (311) away from the second lens (3). There is a medium between the circularly polarized light generating component (5) and the beam-splitting element (311), and the refractive index n2 of the medium between the circularly polarized light generating component (5) and the beam-splitting element (311) satisfies: n2 ≥ 1.

3.

2. The near-eye optical display system according to claim 1, wherein The beam-splitting element (311) is a semi-transmissive and semi-reflective film layer, and the refractive index n1 of the media in contact on both sides of it satisfies: 1.3 ≤ n1 ≤ 1.

8.

3. The near-eye optical display system according to claim 1 or 2, characterized in that, The medium between the circularly polarized light generating component (5) and the beam-splitting element (311) includes at least one of optical glue and a lens.

4. The near-eye optical display system according to claim 1, wherein The composite film material further includes a first polarization element (412), and the first polarization element (412) is stacked on one side surface of the polarization reflection element (413) facing away from the first phase retarder (414).

5. The near-eye optical display system according to claim 1, wherein The circularly polarized light generating component (5) includes a second phase retarder, a third phase retarder, and a second polarization element arranged between the second phase retarder and the third phase retarder.

6. The near-eye optical display system according to claim 1, wherein The surface of the second lens (3) facing away from the first lens (2) is a concave surface, and its radius of curvature ranges from -60 mm to -40 mm.

7. The near-eye optical display system according to claim 1, characterized in that, The optical power φ1 of the first lens (2) satisfies: 0.014 ≤ φ1 ≤ 0.016; The optical power φ2 of the second lens (3) satisfies: 0.007 ≤ φ2 ≤ 0.008; The optical power φ3 of the third lens (4) satisfies: -0.02 ≤ φ3 ≤ -0.

001.

8. The near-eye optical display system according to claim 7, wherein The near-eye optical display system further includes a display screen (1), and the display screen (1) is located on the side of the first lens (2) away from the second lens (3). The air gap B between the display screen (1) and the first lens (2) satisfies: 0.4 mm ≤ B ≤ 0.7 mm.

9. The near-eye optical display system according to claim 8, wherein The ratio of the maximum effective optical diameter Dmax of the lens in the near-eye optical display system to the optical total length TTL of the near-eye optical display system satisfies: 2.5 ≤ Dmax / TTL ≤ 3.

10. The near-eye optical display system according to claim 8 or 9, characterized in that, The optical total length TTL of the near-eye optical display system satisfies: 15 mm ≤ TTL ≤ 17 mm.

11. The near-eye optical display system according to claim 8, characterized in that, The number of lenses n between the circularly polarized light generating component (5) and the display screen (1) is n ≥ 1.

12. An intelligent head-mounted device, characterized in that, Comprising: A housing; And The near-eye optical display system according to any one of claims 1-11.

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