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

Abstract

The present application provides a near-eye optical display system and an intelligent head-mounted device; the near-eye optical display system includes a first lens, a second lens and a third lens arranged in sequence along the optical axis, wherein: a surface of the second lens close to the first lens is provided with a spectroscopic element; a surface of the third lens close to the first lens is provided with a composite film material, the composite film material includes a first phase retarder and a polarization reflection element arranged in a stacked manner, and the first phase retarder is located on the optical path between the spectroscopic element and the polarization reflection element; the near-eye optical display system also includes a circularly polarized light generating component for converting light of a specific polarization state into circularly polarized light, the circularly polarized light generating component is arranged on the side of the spectroscopic element away from the second lens, there is a medium between the circularly polarized light generating component and the spectroscopic element, and the refractive index n2 of the medium between the circularly polarized light generating component and the spectroscopic element satisfies: n2 ≥ 1.3.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of optical display systems. More specifically, the 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 a key trend in VR development. However, image quality and ghosting in optical systems remain key factors affecting user experience. Ghosting is often caused by reflections between lens surfaces. To reduce ghosting, traditional methods often use lens bonding. However, this approach loses design variables and is not conducive to further optimizing image quality.

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

[0004] The purpose of this 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, an embodiment of the present application provides a near-eye optical display system, the near-eye optical display system comprising a first lens, a second lens, and a third lens sequentially spaced apart along an optical axis, wherein:

[0006] A beam splitter is provided on a surface of the second lens close to the first lens, and the beam splitter is used to partially reflect and partially transmit incident light;

[0007] A composite film is provided on a surface of the third lens on a side close to the first lens, wherein the composite film includes a first phase retarder and a polarizing reflective element stacked together, and the first phase retarder is located on an optical path between the beam splitting element and the polarizing reflective element;

[0008] The distance P between the second lens and the third lens is 0.2 mm ≤ P ≤ 0.5 mm;

[0009] The near-eye optical display system also includes a circularly polarized light generating component for converting light of a specific polarization state into circularly polarized light. The circularly polarized light generating component is arranged on the side of the spectroscopic element away from the second lens. There is a medium between the circularly polarized light generating component and the spectroscopic element, and the refractive index n2 of the medium between the circularly polarized light generating component and the spectroscopic element satisfies: n2 ≥ 1.3.

[0010] Optionally, the light splitting element is a semi-transparent and semi-reflective film layer, and the refractive index n1 of the medium in contact with the two sides of the light splitting element satisfies: 1.3≤n1≤1.8.

[0011] Optionally, the medium between the circularly polarized light generating component and the beam splitting element includes at least one of optical glue and a lens.

[0012] Optionally, the composite film further includes a first polarizing element, and the first polarizing element is stacked on a surface of the polarizing reflective element that is away from the first phase retarder.

[0013] Optionally, the circularly polarized light generating component 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.

[0014] Optionally, a surface of the second lens facing away from the first lens is a concave surface, and a curvature radius thereof ranges from -60 mm to -40 mm.

[0015] Optionally, the optical power φ1 of the first lens is 0.014≤φ1≤0.016;

[0016] The optical power φ2 of the second lens is 0.007≤φ2≤0.008;

[0017] The optical power φ3 of the third lens is -0.02≤φ3≤-0.001.

[0018] Optionally, the near-eye optical display system further includes a display screen, which is located on a side of the first lens facing away from the second lens, and an air gap B between the display screen and the first lens satisfies: 0.4 mm ≤ B ≤ 0.7 mm.

[0019] Optionally, a ratio of a maximum effective optical diameter Dmax of a lens in the near-eye optical display system to a total optical length TTL of the near-eye optical display system satisfies: 2.5≤Dmax / TTL≤3.

[0020] Optionally, a total optical length TTL of the near-eye optical display system satisfies: 15 mm ≤ TTL ≤ 17 mm.

[0021] Optionally, the number n of lenses between the circularly polarized light generating component and the display screen is ≥1.

[0022] In a second aspect, an embodiment of the present application provides a smart head-mounted device, the smart head-mounted device comprising:

[0023] casing; and

[0024] A near-eye optical display system as described in the first aspect.

[0025] The beneficial effects of this application are:

[0026] The near-eye optical display system provided in the embodiment of the present application proposes an effective solution to the technical problem of the difficulty in achieving both high imaging quality and low ghosting in the field of VR imaging display, thereby achieving the dual optimization goals of improving image quality and suppressing ghosting.

[0027] Specifically, the present invention employs a design that ensures a refractive index n2 ≥ 1.3 for the medium between the beam splitter and the circularly polarized light generating assembly, creating a refractive index difference of at least 0.3 between this medium and air (refractive index n≈1). This design significantly reduces reflected light energy at the critical optical interface between the beam splitter and the circularly polarized light generating assembly. Experimental data shows that the reduction in reflected light energy can exceed 50%, effectively suppressing ghosting and significantly improving image purity and clarity, delivering a clearer visual experience for users. Furthermore, the present invention utilizes a non-cemented optical path design, with each lens element independent from the others. This eliminates the aberrations introduced by the cemented layers between the lenses in traditional solutions. For example, the lenses in this application are independently positioned, with a certain spacing between the second and third lenses. This design offers the advantage of an additional aspheric degree of freedom over cemented lenses, facilitating aberration correction and improving image quality.

[0028] 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

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0030] Figure 1 One of the structural schematic diagrams of the near-eye optical display system provided in an embodiment of the present application;

[0031] Figure 2 A schematic diagram of a composite film material for a near-eye optical display system provided in an embodiment of the present application;

[0032] Figure 3 for Figure 1 A dot array diagram of a near-eye optical display system is shown;

[0033] Figure 4 for Figure 1 MTF diagram of the near-eye optical display system shown;

[0034] Figure 5 for Figure 1 The field curvature and optical distortion diagram of the near-eye optical display system shown;

[0035] Figure 6 for Figure 1The vertical axis chromatic aberration diagram of the near-eye optical display system is shown;

[0036] Figure 7 This is a second structural diagram of the near-eye optical display system provided in an embodiment of the present application;

[0037] Figure 8 for Figure 7 A dot array diagram of a near-eye optical display system is shown;

[0038] Figure 9 for Figure 7 MTF diagram of the near-eye optical display system shown;

[0039] Figure 10 for Figure 7 The field curvature and optical distortion diagram of the near-eye optical display system shown;

[0040] Figure 11 for Figure 7 The vertical axis chromatic aberration diagram of the near-eye optical display system is shown;

[0041] Figure 12 The third structural diagram of the near-eye optical display system provided in an embodiment of the present application;

[0042] Figure 13 for Figure 12 A dot array diagram of a near-eye optical display system is shown;

[0043] Figure 14 for Figure 12 MTF diagram of the near-eye optical display system shown;

[0044] Figure 15 for Figure 12 The field curvature and optical distortion diagram of the near-eye optical display system shown;

[0045] Figure 16 for Figure 12 The vertical axis chromatic aberration diagram of the near-eye optical display system is shown;

[0046] Figure 17 This is the ghost energy distribution of the conventional optical path;

[0047] Figure 18 Ghost energy distribution of the near-eye optical display system provided in an embodiment of the present application.

[0048] Description of reference numerals:

[0049] 1. Display screen; 2. First lens; 21. First surface; 22. Second surface; 3. Second lens; 31. Third surface; 32. Fourth surface; 311. Beam splitter; 4. Third lens; 41. Fifth surface; 411. Anti-reflection film; 412. Polarization element; 413. Polarized reflection element; 414. Phase retarder; 42. Sixth surface; 5. Circularly polarized light generating component; 01. Human eye. DETAILED DESCRIPTION

[0050] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0051] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0052] 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.

[0053] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0054] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0055] The near-eye optical display system and smart head-mounted device provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0056] According to one embodiment of the present application, a near-eye optical display system is provided. Figure 1 and Figure 2The near-eye optical display system includes a first lens 2, a second lens 3, and a third lens 4 arranged in sequence along the optical axis, wherein: the second lens 3 is provided with a beam splitter 311 on a side surface close to the first lens 2, and the beam splitter 311 is used to partially reflect and partially transmit the incident light; the third lens 4 is provided with a composite film on a side surface close to the first lens 2, and the composite film includes a first phase retarder 414 and a polarization reflection element 413 stacked, and the first phase retarder 414 is located between the beam splitter 311 and the polarization reflection element 413. On the optical path between the elements 413, the spacing P between the second lens 3 and the third lens 4 is 0.2mm≤P≤0.5mm; the near-eye optical display system also includes a circularly polarized light generating component 5, which is used to convert light of a specific polarization state into circularly polarized light, and the circularly polarized light generating component 5 is arranged on the side of the spectroscopic element 311 away from the second lens 3. There is a medium between the circularly polarized light generating component 5 and the spectroscopic element 311, and the refractive index n2 of the medium between the circularly polarized light generating component 5 and the spectroscopic element 311 satisfies: n2≥1.3.

[0057] The near-eye optical display system provided in the embodiments of this application has broad application potential, particularly in the field of VR (virtual reality) optical display. Thanks to its unique optical design and excellent optical performance, the near-eye optical display system provided in the embodiments of this application also has the potential for application in other near-eye optical display fields, such as AR (augmented reality).

[0058] In response to the problem in the prior art of achieving both high imaging quality and low ghosting, the embodiments of the present application propose a new design of a near-eye optical display system, which will be described in detail below.

[0059] The near-eye optical display system provided in the embodiment of the present application is shown in FIG. Figure 1 , which includes three lenses: a first lens 2, a second lens 3 and a third lens 4. Figure 1 As can be seen in the optical layout shown in Figure 2, the three lenses are not bonded together using the traditional method. Instead, they are independently positioned with a certain air gap (e.g., 0.3mm-0.4mm) between each lens. This non-bonded design effectively avoids the aberration issues that could be introduced by bonding layers.

[0060] Optionally, the near-eye optical display system provided in the embodiment of the present application includes but is not limited to three lenses, and may also be two lenses or other numbers of lenses.

[0061] 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 eliminated.

[0062] For example, when the near-eye optical display system of the present application includes four lenses, a lens can be arranged between the light splitting element 311 and the circularly polarized light generating component 5 .

[0063] The following is a detailed description of each optical element in the near-eye optical display system provided in the embodiments of the present application.

[0064] First lens 2: As the starting lens element of the near-eye optical display system provided in an embodiment of the present application, the first lens 2 is responsible for 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.

[0065] The second lens 3, the spectroscopic element 311 and the 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 spectroscopic element 311 and the circularly polarized light generating component 5 are arranged on the surface of the second lens 3 on the side close to the first lens 2.

[0066] Specifically, see Figure 1 , the spectroscopic element 311 is arranged on a side surface (i.e., the third surface 31) of the second lens 3 close to the first lens 2, and the spectroscopic element 311 adopts, for example, a semi-transparent and semi-reflective film layer. In an embodiment of the present application, the main function of the spectroscopic element 311 is to partially reflect and partially transmit the incident light. This characteristic is crucial for realizing the light path control of the optical display system. Furthermore, the circularly polarized light generating component 5 is also introduced on the side of the spectroscopic element 311 away from the second lens 3. The circularly polarized light generating component 5 is mainly used to convert light of a specific polarization state into circularly polarized light. The circularly polarized light generating component 5 and the spectroscopic element 311 can work together to jointly optimize the optical performance of the optical display system.

[0067] There is a medium between the light splitting element 311 and the circularly polarized light generating component 5 , and the medium is, for example, optical glue, and the optical glue is, for example, OCA glue or UV glue.

[0068] Of course, one or more lenses with a specific refractive index may also be arranged between the light splitting element 311 and the circularly polarized light generating component 5 .

[0069] The third lens 4, the first phase retarder 414 and the polarized reflection element 413: The third lens 4 is the last lens element in the optical path. It is responsible for further adjusting and focusing the light processed by the first two lenses (i.e., the first lens 2 and the second lens 3), ensuring that these rays can enter the human eye 01 and ultimately form a clear visual image.

[0070] The first phase retarder 414, which may be, for example, a quarter-wave plate, is primarily used to phase-delay light, thereby changing the polarization state of the light. The polarized reflective element 413, which may be, for example, a polarized reflective film, is capable of reflecting or transmitting light according to its polarization state. In the near-eye optical display system provided in an embodiment of the present application, the polarized reflective element 413 and the first phase retarder 414 work in conjunction to ensure that only light of a specific polarization state is effectively utilized, which helps improve the clarity and purity of the image.

[0071] The polarization reflection element 413 , the first phase retarder 414 and the light splitting element 311 cooperate with each other to form a folded optical path.

[0072] In the near-eye optical display system provided in the embodiment of the present application, the design of the medium refractive index n2 is a key technical point, which refers to the design of the medium refractive index between the circularly polarized light generating component 5 and the spectroscopic element 311. The following is an analysis of the design of the medium refractive index n2.

[0073] In this application, the refractive index n2 of the medium between the beam splitter element 311 and the circularly polarized light generating assembly 5 is controlled to meet the optical parameter design requirement of n2 ≥ 1.3, ensuring a significant difference (e.g., a refractive index difference of at least 0.3) between the medium's refractive index n2 and the refractive index of air (n ≈ 1). This refractive index difference can be used to reduce the reflectivity of key optical interfaces in the optical path between the beam splitter element 311 and the circularly polarized light generating assembly 5, thereby effectively reducing the generation of reflected light. The reduction in reflected light directly leads to the effective suppression of "ghosting," which is typically caused by reflections between lens surfaces. Through this optical parameter design in this application, the purity and visual clarity of the resulting image are greatly improved.

[0074] In this application, the spacing P between the second lens 3 and the third lens 4 is 0.2 mm ≤ P ≤ 0.5 mm. This means that a certain air gap is maintained between the two lenses. Compared to traditional cemented lenses, this provides an additional aspheric degree of freedom, which facilitates aberration correction and improves image quality.

[0075] Optionally, a distance 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, or 0.5 mm.

[0076] It should be noted that the interval P between the second lens 3 and the third lens 4 refers to the air interval between the two lenses in the optical axis direction.

[0077] Furthermore, the design of the medium refractive index n2 in this application not only focuses on ghost image suppression but also fully considers the optimization of overall optical performance. For example, by adopting a non-cemented optical path design, the independence and optimal optical performance of each lens, such as the first lens 2, the second lens 3, and the third lens 4, are ensured, avoiding the aberration issues that may be introduced in traditional cemented solutions. This design allows each lens to fully utilize its optical properties, further improving overall imaging quality.

[0078] In summary, the design of the medium refractive index n2 in the embodiments of this application is a key design point in near-eye optical display systems. By optimizing the medium refractive index between the beam splitter element 311 and the circularly polarized light generating assembly 5, it achieves the dual goals of ghost suppression and improved imaging quality, providing users with a clearer and purer visual experience.

[0079] In some examples of the present application, the light splitting element 311 is a semi-transparent and semi-reflective film layer, and the refractive index n1 of the medium in contact with the two sides of the light splitting element 311 satisfies: 1.3≤n1≤1.8.

[0080] In the example provided herein, the beam splitter element 311 is a semi-transparent, semi-reflective film layer, and the refractive index of the medium in contact with it on both sides is set to n1, and n1 is designed to be within the range of 1.3 to 1.8. This optical parameter design is synergistically optimized with the requirement that the refractive index of the medium between the circularly polarized light generating component 5 and the beam splitter element 311 be n2 ≥ 1.4, and also brings the following significant technical effects:

[0081] By maintaining a reasonable refractive index of the medium on both sides of the light splitting element 311, the stability of light propagation inside the near-eye optical display system is ensured. Figure 1 The 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] It should be noted that the use of optical adhesive and lenses as the medium between the beam splitter element 311 and the circularly polarized light generating assembly 5 can meet the refractive index n2 requirement set forth in this application. Specifically, by selecting the type of optical adhesive and the material of the lens, the refractive index of this region can be adjusted, ensuring that light follows the designed optical path when transmitted between the beam splitter element 311 and the circularly polarized light generating assembly 5, effectively reducing light scattering and reflection, thereby optimizing the imaging quality and ghosting suppression of the entire near-eye optical display system.

[0091] In some examples of this application, see Figure 1 and Figure 2 The composite film further includes a first polarizing element 412 , which is stacked on a surface of the polarizing reflective element 413 facing away from the first phase retarder 414 .

[0092] A polarizing element (i.e., a polarizing film) is an optical element that filters out light with a specific polarization direction. In the composite film material of this application, the first polarizing element 412 can be used to further purify the light reflected by the polarized reflective element 413, ensuring that only light with a specific polarization direction continues to propagate.

[0093] The present application is designed to integrate the first phase retarder 414, the polarized reflecting element 413 and the first polarizing element 412 to form a stacked structure, wherein the first phase retarder 414 converts the incident light into a specific polarization direction, the polarized reflecting element 413 selectively reflects the light in this polarization direction, and the first polarizing element 412 further purifies the reflected light, reduces light loss, and improves the overall light utilization efficiency.

[0094] In addition, the first phase retarder 414 , the polarization reflection element 413 and the first polarization element 412 are integrated together to form a stacked structure, which can also simplify the optical design.

[0095] Optionally, the composite film further comprises an anti-reflection film 411, see Figure 2 .

[0096] Anti-reflection coatings are thin films applied to the surface of optical components to reduce light reflection and increase light transmittance. They improve light transmission efficiency by reducing reflections caused by differences in refractive index when light travels from one medium to another.

[0097] In the composite film provided herein, the anti-reflection film 411 can effectively reduce light reflection losses on the surface of optical elements (such as the third lens 4). The application of the anti-reflection film 411 can significantly increase light transmittance, allowing more light to travel along the designed path and ultimately enter the human eye 01, thereby improving image brightness and contrast.

[0098] Reducing reflected light not only improves light transmittance but also helps reduce glare and stray light. Glare and stray light can reduce image clarity and contrast, affecting the user's visual experience. The application of the anti-reflective film 411 can effectively suppress the generation of these undesirable light rays, improving the purity and quality of the image.

[0099] The anti-reflection film 411 can also serve as a protective layer to provide an additional layer of protection for the optical element and extend its service life.

[0100] In some examples of this application, see Figure 1 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.

[0101] The circularly polarized light generating assembly 5 is mainly composed of a second phase retarder, a second polarizing element, and a third phase retarder stacked in sequence, and is integrated together with the light splitting element 311 on the side surface of the second lens 3 close to the first lens 2 (see Figure 1 On the third surface 31).

[0102] The circularly polarized light generation assembly 5 provided in this application achieves precise phase retardation and polarization state selection of light through the combination of a dual phase retarder and a polarizing element. This design not only improves the efficiency and quality of circularly polarized light generation, but also reduces the occurrence of ghosting, providing a clearer and purer visual experience for near-eye optical display systems.

[0103] Stray light and ghosting are common problems in near-eye optical systems, reducing image clarity and contrast. The circularly polarized light generating assembly 5 in this example effectively reduces these issues by selectively reflecting and transmitting light with a specific polarization direction, thereby improving image purity and clarity.

[0104] In some examples of this application, see Figure 1 The surface of the second lens 3 facing away from the first lens 2 is a concave surface, and its curvature radius ranges from -60mm to -40mm.

[0105] This concave surface, a key refractive surface in the near-eye optical display system, effectively compensates for the astigmatism introduced by the front-surface beam splitter 311, thereby improving overall image clarity. Simultaneously, this concave surface works in conjunction with the first lens 2 to correct the field curvature of the near-eye optical display system, ensuring image uniformity across the entire field of view. Furthermore, by precisely controlling the radius of curvature of the concave surface, the distortion of the near-eye optical display system can be reduced, providing a more realistic, distortion-free visual experience.

[0106] The combination of the concave curvature radius and the refractive index design (n2 ≥ 1.4) achieves effective deflection of stray light, directing it to the non-imaging area, thereby reducing the interference of stray light on imaging quality.

[0107] 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, and bringing clearer visual effects to users.

[0108] In some examples of the present application, the focal power φ1 of the first lens 2 is 0.014≤φ1≤0.016; the focal power φ2 of the second lens 3 is 0.007≤φ2≤0.008; and the focal power φ3 of the third lens 4 is -0.02≤φ3≤-0.001.

[0109] In the examples of this 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; and 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 optical power distribution is based on a comprehensive consideration of the imaging quality, ghost image suppression, and overall performance optimization of the entire near-eye optical display system.

[0110] By rationally allocating the focal power 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 light reflection on the lens surface. In particular, when the first lens 2 and the second lens 3 maintain positive focal power, while the third lens 4 has a negative focal power, this configuration helps to form a more reasonable optical path structure, allowing light to propagate more smoothly when passing through the lens group, thereby reducing surface reflectivity.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] In addition, reasonable control of the air gap B can also control the size of the near-eye optical display system.

[0119] In some examples of the present application, a ratio of a maximum effective optical diameter Dmax of a lens in the near-eye optical display system to a total optical length TTL of the near-eye optical display system satisfies: 2.5≤Dmax / TTL≤3.

[0120] When the Dmax / TTL ratio is within the range of 2.5 to 3, the lenses in the near-eye optical display system can effectively capture and focus light from the display screen 1, reducing light loss and scattering, thereby improving image clarity and contrast. Furthermore, this reasonable ratio design helps correct aberrations in the near-eye optical display system, such as spherical aberration and coma, further improving image quality.

[0121] Furthermore, by controlling the ratio of Dmax to TTL, the overall length of the near-eye optical display system can be reduced while maintaining optical performance, achieving a more compact system design. A compact near-eye optical display system design helps reduce the size and weight of the device, improving user comfort.

[0122] 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.

[0123] Keeping the TTL within the range of 15mm to 17mm helps reduce the overall length of the system and achieve a compact design. The compact system design not only reduces the size and weight of the device, but also improves user comfort and portability.

[0124] In some examples of the present application, the number n of lenses between the circularly polarized light generating component 5 and the display screen 1 is ≥1.

[0125] In optical systems, aberration is a key factor affecting image quality. In the near-eye optical display system provided by the present embodiment, by disposing at least one lens between the circularly polarized light generating assembly 5 and the display screen 1, aberrations generated during light transmission, such as spherical aberration, coma, and astigmatism, can be effectively corrected and compensated. This correction makes the image ultimately projected onto the display screen 1 clearer, significantly improving overall image quality.

[0126] The addition of lenses not only changes the propagation path of light but also focuses and shapes it through its specific optical properties (such as curvature and refractive index). This optimized design helps reduce light loss during transmission and improves the utilization of light energy.

[0127] The near-eye optical display system design provided in the embodiment of the present application includes three lenses: a first lens 2, a second lens 3 and a third lens 4. The refractive index n and the dispersion coefficient v of these three lenses are in the range of: 1.4 <n<2.0,20<v<75。

[0128] The optical path design of the near-eye optical display system provided in the embodiment of the present application has been carefully optimized to achieve high-quality imaging effects and ghost suppression. The specific optical path is described as follows, see Figure 1 :

[0129] Light emitted by the display screen 1 first passes through the protective glass on its surface, then sequentially passes through the first lens 2 and the second lens 3. The light then reaches the fifth surface 41 of the third lens 4 and is reflected, before being reflected again by the third surface 31 of the second lens 3. After being processed by the second lens 3, the light continues to propagate, passing through the third lens 4 and ultimately entering the human eye 01, allowing the user to clearly observe the image.

[0130] The light emitted from the display screen 1 will be converted into circularly polarized light when encountering the circularly polarized light generating component 5 on the third surface 31 of the second lens 3 .

[0131] During this process, the sixth surface 42 of the third lens 4 may be coated with an anti-reflection coating to reduce light loss during transmission. Ultimately, the light forms a clear image at the human eye 01, and ghosting is effectively suppressed due to the optimized optical path design.

[0132] The near-eye optical display system provided in the embodiment of the present application has achieved remarkable results in suppressing ghost images. For specific results, please refer to Figure 17 and Figure 18The ghost energy distribution comparison diagram is shown.

[0133] Figure 17 Shows the ghost energy distribution under the conventional optical path. Figure 17 It can be clearly observed that there is an obvious ring-shaped high-energy ghost area (such as Figure 17 These ghost images (shown in the circled area on the center outer edge) have peak intensities as high as 8% to 12% of the main image brightness, and their energy is distributed widely, occupying 35% to 40% of the field of view. This ghosting phenomenon severely impacts the user's visual experience, reducing image clarity and purity.

[0134] Figure 18 The figure shows the ghost energy distribution of the near-eye optical display system of this application. Compared with conventional optical paths, the system of this application almost completely eliminates the ring ghost phenomenon, reducing the ghost energy to an invisible level. The residual ghost intensity is less than 0.5% of the main image brightness, and the energy distribution is more concentrated, accounting for only 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.

[0135] The near-eye optical display system of the present application is described below through Examples 1 to 3.

[0136] Example 1

[0137] The near-eye optical display system provided in this embodiment 1 is shown in FIG. Figure 3 , comprising a display screen 1, a first lens 2, a circularly polarized light generating component 5, a beam splitter 311, a second lens 3, a composite film material, and a third lens 4, which are sequentially arranged along the same optical axis, and an OCA glue is provided between the circularly polarized light generating component 5 and the beam splitter 311. The refractive index of the OCA glue is 1.54, that is, the refractive index n2 of the medium in this embodiment 1 is 1.54;

[0138] 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;

[0139] 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;

[0140] 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 splitter 311 and the circularly polarized light generating assembly 5 are disposed on the third surface 31. The optical power φ2 of the second lens 3 is designed to be 0.0075.

[0141] The third lens 4 includes a fifth surface 41 and a sixth surface 42 , and the composite film is disposed on the fifth surface 41 ; the focal power φ3 of the third lens 4 is designed to be -0.018;

[0142] The interval P between the second lens 3 and the third lens 4 is 0.3 mm;

[0143] See also Figure 2 The composite film material includes a first phase retarder 414, a polarizing reflective element 413, a first polarizing element 412, and an anti-reflection film 411 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 polarizing reflective element 413;

[0144] 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.

[0145] The optical parameters of the near-eye optical display system provided in this embodiment 1 are shown in Table 1 below.

[0146] Table 1

[0147]

[0148] The near-eye optical display system provided in this embodiment 1 has optical performance such as Figures 3 to 6 As shown: Figure 3 is a point diagram diagram. Figure 4 is the MTF curve graph, Figure 5 It is the field curvature and distortion diagram, Figure 6 This is a diagram of vertical chromatic aberration.

[0149] A spot diagram is a diffuse pattern formed when many light rays emitted from one point pass through a near-eye optical display system. Due to aberration, their intersection with the image plane is no longer concentrated at the same point, but is spread over a certain range. It is used to evaluate the imaging quality of the projection near-eye optical display system. Figure 3 In the near-eye optical display system provided in this embodiment 1, the maximum value of the image point in the point array diagram is less than 71 μm.

[0150] The MTF curve is a modulation transfer function graph that characterizes the imaging clarity of a near-eye optical display system through the contrast of black and white line pairs. Figure 4 The near-eye optical display system provided in this embodiment 1 has an MTF of >0.4 at 20lp / mm.

[0151] See also Figure 5 In the near-eye optical display system provided in this embodiment 1, the maximum distortion occurs in 1 field of view, and the absolute value is less than 46%.

[0152] Vertical axial chromatic aberration is also called chromatic aberration of magnification. It mainly refers to the difference in the focal position of blue light and red light on the image plane when a complex main light on the object side is transformed into multiple light rays due to the dispersion of the refraction system. Figure 6 The near-eye optical display system provided in this embodiment 1 has a maximum color difference value of less than 300 μm.

[0153] Example 2

[0154] The near-eye optical display system provided in this embodiment 2 is shown in FIG. Figure 7 , comprising a display screen 1, a first lens 2, a circularly polarized light generating component 5, a beam splitter 311, a second lens 3, a composite film material, and a third lens 4, which are sequentially arranged along the same optical axis, and a UV adhesive is provided between the circularly polarized light generating component 5 and the beam splitter 311. The refractive index of the UV adhesive is 1.6, that is, the refractive index n2 of the medium in this embodiment 2 is 1.6;

[0155] 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;

[0156] 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;

[0157] 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 splitter 311 and the circularly polarized light generating assembly 5 are disposed on the third surface 31. The optical power φ2 of the second lens 3 is designed to be 0.0072.

[0158] The third lens 4 includes a fifth surface 41 and a sixth surface 42 , and the composite film is disposed on the fifth surface 41 ; the optical power φ3 of the third lens 4 is designed to be -0.004;

[0159] The interval P between the second lens 3 and the third lens 4 is 0.2 mm;

[0160] See also Figure 2 The composite film material includes a first phase retarder 414, a polarizing reflective element 413, a first polarizing element 412, and an anti-reflection film 411 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 polarizing reflective element 413;

[0161] 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.

[0162] The optical parameters of the near-eye optical display system provided in this embodiment 2 are shown in Table 2 below.

[0163] Table 2

[0164]

[0165] The near-eye optical display system provided in this embodiment 2 has optical performance such as Figures 8 to 11 As shown: Figure 8 is a point diagram diagram. Figure 9 is the MTF curve graph, Figure 10 It is the field curvature and distortion diagram, Figure 11 This is a diagram of vertical chromatic aberration.

[0166] See also Figure 8 In the near-eye optical display system provided in this embodiment 2, the maximum value of the image point in the point array diagram is less than 26 μm.

[0167] See also Figure 9 The near-eye optical display system provided in this embodiment 2 has an MTF of >0.4 at 20lp / mm.

[0168] See also Figure 10 In the near-eye optical display system provided in Example 2, the maximum distortion occurs in 1 field of view, and the absolute value is less than 46%.

[0169] See also Figure 11 The near-eye optical display system provided in this embodiment 2 has a maximum color difference value of less than 300 μm.

[0170] Example 3

[0171] The near-eye optical display system provided in this embodiment 3 is shown in FIG. Figure 12 , comprising a display screen 1, a first lens 2, a circularly polarized light generating component 5, a beam splitter 311, a second lens 3, a composite film material, and a third lens 4, which are sequentially arranged along the same optical axis, and a UV adhesive is provided between the circularly polarized light generating component 5 and the beam splitter 311, and the refractive index of the UV adhesive is 1.7, that is, the refractive index n2 of the medium in this embodiment 2 is 1.7;

[0172] 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;

[0173] 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;

[0174] 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 splitter 311 and the circularly polarized light generating assembly 5 are disposed on the third surface 31. The optical power φ2 of the second lens 3 is designed to be 0.0077.

[0175] The third lens 4 includes a fifth surface 41 and a sixth surface 42 , and the composite film is disposed on the fifth surface 41 ; the optical power φ3 of the third lens 4 is designed to be -0.0017;

[0176] The interval P between the second lens 3 and the third lens 4 is 0.4 mm;

[0177] See also Figure 2 The composite film material includes a first phase retarder 414, a polarizing reflective element 413, a first polarizing element 412, and an anti-reflection film 411 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 polarizing reflective element 413;

[0178] 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.

[0179] The optical parameters of the near-eye optical display system provided in this embodiment 3 are shown in Table 3 below.

[0180] Table 3

[0181]

[0182] The near-eye optical display system provided in this embodiment 3 has optical performance such as Figures 13 to 16 As shown: Figure 13 is a point diagram diagram. Figure 14 is the MTF curve graph, Figure 15 It is the field curvature and distortion diagram, Figure 16 This is a diagram of vertical chromatic aberration.

[0183] See also Figure 13 In the near-eye optical display system provided in this embodiment 3, the maximum value of the image point in the point array diagram is less than 20 μm.

[0184] See also Figure 14 The near-eye optical display system provided in Example 3 has an MTF of >0.4 at 20lp / mm.

[0185] See also Figure 15In the near-eye optical display system provided in Example 3, the maximum distortion occurs in 1 field of view, and the absolute value is less than 46%.

[0186] See also Figure 16 The near-eye optical display system provided in this embodiment 3 has a maximum color difference value of less than 300 μm.

[0187] According to another embodiment of the present application, a smart head-mounted device is provided, comprising a housing and the above-described near-eye optical display system, wherein the near-eye optical display system is disposed in the housing.

[0188] The smart head-mounted device provided in the embodiment of the present application is, for example, a VR head-mounted display device.

[0189] The specific implementation of the intelligent head-mounted device of the embodiment of the present application can refer to the various embodiments of the above-mentioned near-eye optical display system, and therefore has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0190] 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.

[0191] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It should be understood by those skilled in the art that the above examples may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A near-eye optical display system, characterized in that: It comprises a first lens (2), a second lens (3) and a third lens (4) which are sequentially spaced apart along the optical axis, wherein: A light splitting element (311) is provided on a surface of the second lens (3) on one side close to the first lens (2), and the light splitting element (311) is used to partially reflect and partially transmit incident light; A composite film is provided on a surface of the third lens (4) on one side close to the first lens (2), the composite film comprising a first phase retarder (414) and a polarized reflective element (413) arranged in a stacked manner, and the first phase retarder (414) is located on an optical path between the light splitting element (311) and the polarized reflective element (413); The spacing 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 comprises a circularly polarized light generating component (5) for converting light of a specific polarization state into circularly polarized light, wherein the circularly polarized light generating component (5) is arranged on a side of the beam splitting element (311) away from the second lens (3), a medium is present between the circularly polarized light generating component (5) and the beam splitting element (311), and a refractive index n2 of the medium between the circularly polarized light generating component (5) and the beam splitting element (311) satisfies the following condition: n2 ≥ 1.

3.

2. The near-eye optical display system according to claim 1, wherein: The light splitting element (311) is a semi-transparent and semi-reflective film layer, and the refractive index n1 of the medium in contact with the two sides of the light splitting element (311) satisfies the following conditions: 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 light 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 polarizing element (412), which is stacked on a surface of the polarizing reflective 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) comprises 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 curvature radius ranges from -60 mm to -40 mm.

7. The near-eye optical display system according to claim 1, wherein: 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.

8. The near-eye optical display system according to claim 7, wherein: The near-eye optical display system further comprises a display screen (1), wherein the display screen (1) is located on a side of the first lens (2) facing away from the second lens (3), and an air gap B between the display screen (1) and the first lens (2) satisfies the following conditions: 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 total optical 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 total optical 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, wherein: The number of lenses between the circularly polarized light generating component (5) and the display screen (1) is n≥1.

12. A smart head-mounted device, characterized in that: include: shell; and The near-eye optical display system according to any one of claims 1 to 11.

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