Eyepiece system and optical device

Abstract

This application provides an eyepiece system and optical device; wherein, the eyepiece system comprises, along the optical axis from the image source side to the human eye side, a second imaging element group, a third imaging element group, and a first imaging element group; the second imaging element group includes at least two lenses; the third imaging element group includes a third lens movable along the optical axis, at least one of its two surfaces being convex, a beam splitting element being disposed on the surface near the image source side, and a first optical functional film layer being disposed on the surface near the human eye side; the first imaging element group includes a second lens and a first lens arranged sequentially from the image source side to the human eye side and bonded together, and the first lens and the second lens satisfy the relationship: 0.02≤(1 / R)*|δ n |*|δ v |≤0.03, where R is the radius of curvature of the bonding surface between the two lenses, δ n δ represents the difference in refractive index between the two lenses. v This represents the difference in Abbe number between the two lenses.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of optical imaging technology, and more particularly, to an eyepiece system and an optical device. BACKGROUND

[0002] In the field of traditional eyepiece system optical design, straight-through optical scheme has long been dominant. It relies on light transmission through multiple lenses to achieve imaging. In order to achieve clear imaging, appropriate focal length and other specific optical performance indicators, a large number of lenses are often configured. However, this design has the following problems: the stacking of numerous lenses makes the eyepiece system bulky, which not only increases the weight of the device, but also limits its application in portable observation devices, head-mounted display devices and other scenes with strict space requirements; at the same time, the field of view of the straight-through eyepiece system is small, and the range of the user's field of view is limited, which is difficult to meet the needs of fields requiring wide observation. In the early stage, the straight-through design was relatively simple in design and manufacturing process, and could meet the basic optical observation needs and provide basic visual magnification and imaging functions. However, with the advancement of technology, the performance requirements of eyepiece systems in various industries have increased. In the pursuit of higher imaging quality, smaller device size and larger field of view, its limitations have become increasingly prominent, and it has been unable to adapt to modern diversified needs. It is urgent to develop a new type of eyepiece system that can overcome the above-mentioned defects. SUMMARY

[0003] The purpose of the present application is to provide a new technical solution for an eyepiece system and an optical device, which realizes large field of view, high imaging quality and diopter adjustment in a small volume.

[0004] In a first aspect, embodiments of the present application provide an eyepiece system, which comprises, in order from an image source side to a human eye side along an optical axis:

[0005] a second imaging element group comprising at least two lenses;

[0006] a third imaging element group comprising a third lens movable along the optical axis, at least one of two surfaces of the third lens being a convex surface, wherein a surface close to the image source side is provided with a light splitting element, and a surface close to the human eye side is provided with a first optical functional film layer, the first optical functional film layer comprising a first phase retarder and a polarization reflector stacked in order; and

[0007] a first imaging element group comprising a second lens and a first lens arranged in order from the image source side to the human eye side and bonded to each other, and the first lens and the second lens satisfy the relationship: 0.02≤(1 / R)*|δ n |*|δ v |≤0.03, wherein R is the radius of curvature of the bonding surface of the first lens and the second lens, δ n is the refractive index difference between the first lens and the second lens, and δv an Abbe number difference of the first lens and the second lens.

[0008] Optionally, the third lens is located in a folded optical path, both surfaces of the third lens are convex, and an optical path length L of the third lens satisfies: L≥18mm, the optical path length L being a product of a refractive index n3 of the third lens and a central thickness T3 of the third lens on an optical axis, where 12mm≤T3≤18mm.

[0009] Optionally, the third lens is configured to provide a diopter adjustment by moving along the optical axis:

[0010] moving towards the first imaging element group to accommodate a myopic state;

[0011] moving towards the second imaging element group to accommodate a hyperopic state.

[0012] Optionally, an optical power of the third lens φ3 satisfies: 0.004≤φ3≤0.005;

[0013] the third lens is configured to be movable from an initial position along the optical axis to provide a diopter adjustment by changing its relative position to the first imaging element group:

[0014] moving 7mm to 9.5mm towards the first imaging element group enables a diopter adjustment range of 0D to -5D;

[0015] moving 7mm to 9.5mm towards the second imaging element group enables a diopter adjustment range of 0D to +5D;

[0016] wherein, at the initial position, an air gap P of the third lens and the second lens on the optical axis satisfies: 9mm≤P≤10mm.

[0017] Optionally, a refractive index difference |δ n | of the first lens and the second lens satisfies: 0.2≤|δ n |≤0.6, and an Abbe number difference |δ v | of the first lens and the second lens satisfies: 5≤|δ v |≤10.

[0018] wherein the first lens has a positive optical power, the second lens has a negative optical power, a refractive index n2 of the second lens is greater than a refractive index n1 of the first lens, and an Abbe number v2 of the second lens is less than an Abbe number v1 of the first lens.

[0019] Optionally, the first phase retarder is located between the light splitting element and the polarized reflector.

[0020] The first optical functional film layer further comprises a first polarizer, which is stacked on a side surface of the polarized reflector away from the first phase retarder.

[0021] Optionally, the second imaging element group comprises, in sequence from the image source side to the human eye side along the optical axis, a sixth lens, a fifth lens, and a fourth lens.

[0022] The optical power φ of the second imaging element group G2 satisfies: 0.015 ≤ φ G2 ≤ 0.025.

[0023] Optionally, the combined optical power φ of the second imaging element group and the third imaging element group t satisfies: 0.015 ≤ φ t ≤ 0.025.

[0024] Optionally, the total effective focal length F of the eyepiece system satisfies: 30 mm ≤ F ≤ 32 mm.

[0025] Optionally, the eyepiece system further comprises a display screen, which is arranged on the image source side of the second imaging element group.

[0026] Optionally, the eyepiece system further comprises a second optical functional film layer, which comprises, in sequence from the image source side to the human eye side, a second phase retarder, a second polarizer, and a third phase retarder.

[0027] The second optical functional film layer is arranged on a side surface of the fourth lens close to the third imaging element group.

[0028] Optionally, the optical power φ1 of the first lens satisfies: 0.008 ≤ φ1 ≤ 0.01.

[0029] The optical power φ2 of the second lens satisfies: -0.02 ≤ φ2 ≤ -0.01.

[0030] Optionally, the optical power φ4 of the fourth lens satisfies: 0.002 ≤ φ4 ≤ 0.005.

[0031] The optical power φ5 of the fifth lens satisfies: -0.05 ≤ φ5 ≤ -0.01.

[0032] The optical power φ6 of the sixth lens satisfies: 0.02 ≤ φ6 ≤ 0.06.

[0033] Optionally, the surface of the sixth lens close to the human eye side is a convex surface, and the convex surface has at least one inflection point.

[0034] In a second aspect, an embodiment of the present application provides an optical device, which comprises:

[0035] The eyepiece system according to the first aspect; and

[0036] The objective lens system.

[0037] The beneficial effects of the present application are:

[0038] The eyepiece system provided by the embodiments of the present application adopts a layout design from the image source side to the human eye side along the optical axis, and sequentially configures a second imaging element group, a third imaging element group with zooming capability, and a first imaging element group composed of a first lens and a second lens that are bonded to each other. The third imaging element group serves as a zooming unit, internally integrates a light splitting element, a convex lens, and a first optical function film layer in which a first phase retarder and a polarization reflector are stacked, and constructs a folded light path through the synergistic effect of the light splitting element and the first optical function film layer, thereby significantly optimizing the optical transmission path while maintaining the compact structure of the system. The technical advantages of the eyepiece system provided by the present application are embodied in the following three aspects: first, the movement mechanism of the third lens along the optical axis can realize dynamic focal length adjustment for different observation distances (including near vision and far vision scenes), thereby giving the system flexible zooming capability; second, the first imaging element group effectively corrects chromatic aberration in a large field of view environment through a double-bonded lens structure combined with specific parameter conditions, thereby ensuring the imaging clarity of a field of view angle of 40° or more; and third, the folded light path design enables the eyepiece system to achieve a large field of view and high imaging quality while reasonably controlling the overall length, thereby achieving a balance between miniaturization and high performance. The eyepiece system provided by the present application realizes technical breakthroughs in field of view angle expansion, imaging quality improvement, and diopter adjustment in a limited volume through optical architecture innovation.

[0039] Other features of the present specification and its advantages will become apparent from the following detailed description of exemplary embodiments thereof, with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0040] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present specification and, together with the description, serve to explain the principles of the present specification.

[0041] Figure 1 An optical structure and a light path schematic diagram of the eyepiece system provided by the embodiments of the present application;

[0042] Figure 2 A first optical function film layer schematic diagram provided by the embodiments of the present application;

[0043] Figure 3 A second optical function film layer schematic diagram provided by the embodiments of the present application;

[0044] Figure 4 A point array diagram of the eyepiece system provided by the present application; Figure 1

[0045] ​Figure 5 MTF map of the eyepiece system provided in Figure 1

[0046] Figure 6 field curvature and distortion map of the eyepiece system provided in Figure 1

[0047] Figure 7 axial chromatic aberration map of the eyepiece system provided in Figure 1

[0048] Figure 8 optical structure and optical path schematic diagram of the eyepiece system provided in the embodiment of the present application

[0049] Figure 9 dot array map of the eyepiece system provided in Figure 2

[0050] Figure 10 MTF map of the eyepiece system provided in Figure 2

[0051] Figure 11 field curvature and distortion map of the eyepiece system provided in Figure 2

[0052] Figure 12 axial chromatic aberration map of the eyepiece system provided in Figure 2

[0053] BRIEF DESCRIPTION OF DRAWINGS

[0054] 1, display screen; 2, protective glass

[0055] G1, first imaging element group; G2, second imaging element group; G3, third imaging element group

[0056] 3, sixth lens; 31, eleventh surface; 32, twelfth surface

[0057] 4, fifth lens; 41, ninth surface; 42, tenth surface

[0058] 5, fourth lens; 51, seventh surface; 52, eighth surface

[0059] 6, third lens; 61, fifth surface; 62, sixth surface

[0060] 7, second lens; 71, third surface; 72, fourth surface

[0061] 8, first lens; 81, first surface; 82, second surface

[0062] 9, light splitting element

[0063] ​​​​​​​10, first optical functional film layer; 1001, first phase retarder; 1002, polarized reflector; 1003, polarizer; 1004, first anti-reflection film;

[0064] 11, second optical functional film layer; 1101, second phase retarder; 1102, second polarizer; 1103, third phase retarder; 1104, second anti-reflection film;

[0065] 01, human eye. DETAILED DESCRIPTION

[0066] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of the components and steps set forth in the examples, as well as the numerical expressions and numerical values, are not limiting to the scope of the present application unless specifically stated otherwise.

[0067] The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the application or its application or uses.

[0068] Techniques and equipment known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as part of the specification where appropriate.

[0069] In all examples shown and discussed herein, any specific value should be interpreted as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments can have different values.

[0070] It should be noted that like numbers and letters refer to like items throughout the drawings, and once an item is defined in one drawing, it need not be discussed further in subsequent drawings.

[0071] The eyepiece system and optical device provided by the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0072] According to one embodiment of the present application, an eyepiece system is provided, referring to Figure 1 and Figure 8 , the eyepiece system comprises, in order from the image source side to the human eye side along the optical axis: a second imaging element group G2, a third imaging element group G3, and a first imaging element group G1. The second imaging element group G2 comprises at least two lenses. The third imaging element group G3 comprises a third lens 6 that is movable along the optical axis, at least one of the two surfaces of the third lens 6 is convex, wherein the surface close to the image source side is provided with a light splitting element 9, and the surface close to the human eye side is provided with a first optical functional film layer 10, the first optical functional film layer 10 comprises a first phase retarder 1001 and a polarized reflector 1002 stacked in order, referring to Figure 2The first imaging element group G1 includes the second lens 7 and the first lens 8 arranged in sequence from the image source side to the human eye side and cemented to each other, and the first lens 8 and the second lens 7 satisfy the relationship: 0.02≤(1 / R)*|δ n |*|δ v |≤0.03, where R is the radius of curvature of the cemented surface of the first lens 8 and the second lens 7, δ n is the refractive index difference of the first lens 8 and the second lens 7, and δ v is the Abbe number difference of the first lens 8 and the second lens 7.

[0073] The eyepiece system provided in the embodiments of the present application has the second imaging element group G2, the third imaging element group G3 and the first imaging element group G1 arranged in sequence along the optical axis from the image source side to the human eye side, please refer to Figure 1 and Figure 8 . The second imaging element group G2 is designed to have positive focal power and includes at least two lenses, and the second imaging element group G2 provides the basic light converging capability of the entire eyepiece system and mainly performs aberration correction, which helps to effectively improve the imaging quality of the eyepiece system. The third imaging element group G3 includes a third lens 6 movable along the optical axis, the surface of the third lens 6 close to the human eye side (i.e. the sixth surface 62 shown in Figure 1 and Figure 8 ) is designed as a convex surface and integrated with a first optical functional film layer 10, and the surface of the third lens 6 close to the image source side (i.e. the fifth surface 61 shown in Figure 1 and Figure 8 ) is integrated with a light splitting element 9. By controlling the left and right movement of the third lens 6 along the optical axis, the zoom function of the entire eyepiece system can be realized, so the third imaging element group G3 is a zoom group. The first imaging element group G1 is mainly composed of the second lens 7 and the first lens 8 arranged in sequence from the image source side to the human eye side and cemented to each other, and the first imaging element group G1 as a whole can be located outside the folded light path and is mainly responsible for correcting chromatic aberration under large field of view. The field of view of the eyepiece system provided in the present application can reach 40° or more, realizing the perfect combination of high performance and compact structure.

[0074] The eyepiece system provided in the embodiments of the present application can be applied to, for example, sighting optical devices, observation optical devices and the like, and the specific type of optical device can be flexibly set as needed. The eyepiece system provided in the embodiments of the present application is described in detail below.

[0075] Please refer to Figure 1 and Figure 8The eyepiece system of the embodiment of the present application comprises three imaging element groups, which are respectively: a first imaging element group G1 located on one side of the human eye 01, a second imaging element group G2 located on one side of the image source, and a third imaging element group G3 located between the first imaging element group G1 and the second imaging element group G2. The three imaging element groups are described below.

[0076] The first imaging element group G1 is designed to be mainly composed of the second lens 7 and the first lens 8 arranged in order along the optical axis from the image source side to the human eye side and cemented with each other. In the present application, the first imaging element group G1 undertakes the important task of correcting chromatic aberration in a large field of view environment. Specifically, when the eyepiece system faces a field of view (FOV) of 40° or more, light rays are prone to dispersion due to wavelength differences, causing different color light rays to deviate and blur on the imaging plane, seriously affecting image quality. The first imaging element group G1 can effectively correct this dispersion phenomenon through its special lens design and cemented structure, ensuring that all types of light rays can be accurately focused on the imaging plane within a large field of view range, thereby presenting a clear and high color restoration degree image, significantly improving the overall imaging quality of the eyepiece system.

[0077] For the two lenses in the first imaging element group G1, i.e., the first lens 8 and the second lens 7, the present application also optimizes the mathematical relationship that they satisfy: 0.02≤(1 / R)*|δ n |*|δ v ≤0.03, which can bring the following technical effects:

[0078] (1) Optimizing chromatic aberration correction ability: By precisely controlling the product relationship of the curvature radius R, the refractive index difference δ n and the Abbe number difference δ v of the cemented surface of the first lens 8 and the second lens 7, this parameter design can more effectively correct chromatic aberration under a large field of view. Abbe number (also known as dispersion coefficient) reflects the material's ability to disperse light, which together with the refractive index can precisely control the focusing position of light rays of different wavelengths, thereby reducing dispersion and improving the color accuracy and clarity of imaging.

[0079] (2) Enhancing system imaging quality: This parameter range ensures that the cemented lens group can maintain high imaging quality while correcting chromatic aberration. By optimizing the refraction and dispersion characteristics between lenses, it also reduces aberrations such as spherical aberration and coma during light transmission, making the final image clearer and with higher contrast.

[0080] (3) Achieving a compact structural design: Under the premise of ensuring imaging quality, the parameter design of this application helps to achieve a compact optical structure of the eyepiece system. By reasonably controlling the difference in refractive index and Abbe number between the first lens 8 and the second lens 7, as well as the radius of curvature of their cemented surfaces, efficient light convergence and chromatic aberration correction can be achieved in a limited space, thereby reducing the volume and weight of the eyepiece system.

[0081] The above parameter range (0.02≤(1 / R)*|δ) n |*|δ v The design (≤0.03) also enhances the adaptability and flexibility of the eyepiece system for different application scenarios. Whether a large field of view or high-resolution imaging is required, the system can be optimized while meeting imaging quality requirements by adjusting parameters such as lens material and radius of curvature.

[0082] The second imaging element group G2 is designed with positive optical power characteristics, playing a crucial role in the eyepiece system by converging light from the image source. It effectively guides the light to the subsequent processing units, ensuring that the light propagates in the ideal direction and angle, thus laying a solid foundation for achieving clear imaging.

[0083] In this application, the optical design of the second imaging element group G2 places particular emphasis on aberration correction. Through further optimization of its optical power range, the second imaging element group G2 can reduce various aberration phenomena such as spherical aberration, coma, and astigmatism in the eyepiece system. This optimized design not only improves the overall imaging quality of the eyepiece system, making the final image clearer and sharper at the edges, but also enhances the detail representation of the image, bringing a high-quality visual experience to the observer.

[0084] The third imaging element group G3, as the zoom group of the entire eyepiece system, plays a crucial role in flexibly adjusting the focal length to adapt to different imaging needs. The third lens 6 is the core optical component of this third imaging element group G3, and its surface closest to the human eye (i.e., the...) Figure 1 and Figure 8 The sixth surface 62 shown can be designed as a convex surface, which can help to increase the field of view of the entire eyepiece system, for example, to 40° or even larger.

[0085] The surface of the third lens 6 near the image source side (i.e. Figure 1 and Figure 8 The fifth surface 61 shown in the figure is provided with a beam-splitting element 9, which is located on the surface closest to the human eye (i.e., the surface 61). Figure 1 and Figure 8The sixth surface 62 shown in FIG. 6 is provided with a first optical functional film layer 10, which comprises a first phase retarder 1001 and a polarization reflector 1002 arranged in sequence.

[0086] The light splitting element 9 can partially reflect and partially transmit the incident light. This light processing mode cooperates with the first optical functional film layer 10, and the two complement each other to achieve the folding function of the optical path. Through this folded optical path design, the light can be efficiently transmitted and imaged in a limited space, greatly optimizing the optical structure of the eyepiece system, so that the entire eyepiece system is more compact while maintaining high performance.

[0087] Especially noteworthy is that the third lens 6 is designed to move left and right along the optical axis. This design gives the eyepiece system a zoom function. In actual application, whether it is a myopia situation that requires zooming in on the focal length to clearly observe objects close up, or a hyperopia situation that requires zooming out on the focal length to focus on distant targets, simply moving the third lens 6 can adjust the focal length, thereby adapting to different distances and sizes of objects for imaging, providing users with a more convenient and flexible user experience.

[0088] The third imaging element group G3 serves as the zoom core of the eyepiece system, playing a key role in flexibly adjusting the focal length to accurately adapt to different observation distances and vision conditions, including hyperopia and myopia.

[0089] The third lens 6, as the core optical component of the third imaging element group G3, has a surface (i.e. Figure 1 and Figure 8 The sixth surface 62 shown in FIG. 6 is designed as a convex surface, which significantly expands the field of view of the eyepiece system, making the field of view angle up to 40° or even wider, thereby meeting the needs of wide-range observation.

[0090] In terms of optical function design, the surface of the third lens 6 close to the image source side (i.e. Figure 4 and Figure 9 The fifth surface 61 shown in FIG. 5 integrates a light splitting element 9, which can achieve partial reflection and partial transmission of light; while the surface close to the eye side (sixth surface 62) is provided with a first optical functional film layer 10, which is composed of a first phase retarder 1001 and a polarization reflector 1002 arranged in sequence. The light splitting element 9 and the first optical functional film layer 10 work together to achieve the folding function of the optical path through the partial reflection and transmission of light processing mechanism, combined with the selective reflection characteristics of the polarization reflector. This design enables efficient transmission and imaging of light in a limited space, significantly optimizing the optical structure of the entire eyepiece system, ensuring high performance while achieving compact design.

[0091] In particular, the third lens 6 is designed to move left and right along the optical axis. This feature gives the eyepiece system zoom capability: when the observer needs to clearly observe near objects (such as near field scenes), the focal length can be shortened by moving the third lens 6; when the need to focus on distant objects (such as far field scenes), the focal length can be lengthened. This adaptive focal length adjustment mechanism enables the eyepiece system to accurately adapt to the imaging needs of objects of different distances and sizes, providing clear and comfortable viewing experience for both far-sighted and near-sighted users, significantly improving the practicality and adaptability of the product.

[0092] The eyepiece system provided in the present application comprises a plurality of optical films for forming a folded optical path, for example, comprising a light splitting element 9, a first phase retarder 1001, and a polarization reflector 1002, etc.

[0093] The light splitting element 9, for example, is a thin film or coating with specific light splitting properties, which can be used to reflect and transmit incident light in a certain proportion.

[0094] Specifically, the light splitting element 9 used in the present application is a semi-transparent and semi-reflective film, which allows a portion of light to be transmitted and another portion of light to be reflected.

[0095] It should be noted that the reflectivity and transmissivity of the light splitting element 9 can be flexibly adjusted according to specific needs, which is not limited in the embodiments of the present application.

[0096] The first phase retarder 1001 can be used to change the polarization state of light, for example, to convert linearly polarized light into circularly polarized light, or to convert circularly polarized light into linearly polarized light.

[0097] The first phase retarder 1001 used in the present application, for example, is a quarter-wave plate, which is located between the light splitting element 9 and the polarization reflector 1002, and adjusts the phase of light to ensure that the light can be correctly reflected or transmitted in the subsequent path.

[0098] The polarization reflector 1002 is an optical device that reflects horizontally linearly polarized light and transmits vertically linearly polarized light, or any other specific angle linearly polarized light, and transmits linearly polarized light perpendicular to the angle. That is, the polarization reflector 1002 is responsible for reflecting or transmitting according to the polarization state of the light. In the present application, it interacts with the specific state of the polarized light (such as S-polarized light or P-polarized light) to achieve specific path control of the light.

[0099] The polarization reflector 1002 used in the present application, for example, is a polarization reflection film.

[0100] In the eyepiece system provided in the embodiments of the present application, the three imaging element groups work cooperatively to achieve high-performance optical imaging functions. Specifically, the second imaging element group G2 serves as a basic unit for light convergence, and is responsible for converging light emitted from the image source, laying a key foundation for subsequent light processing and imaging quality. The design ensures that light can enter the system in an ideal direction and angle, providing stable input conditions for subsequent optical elements.

[0101] The third imaging element group G3 serves as the zoom core of the eyepiece system, and the third lens 6 therein has the ability to move along the optical axis direction. This feature enables the system to accurately adjust the optical path according to different use scenarios (such as near vision or far vision). When the observer needs to clearly observe the near object (near vision scenario), the third lens 6 can be moved towards the image source to shorten the focal length; when the far target needs to be focused (far vision scenario), the third lens 6 can be moved away from the image source to lengthen the focal length. This dynamic zoom mechanism ensures that light always enters the subsequent optical elements in the best state, thereby achieving high-quality imaging effects.

[0102] At the same time, the first imaging element group G1 corrects the chromatic aberration problem in the large field of view environment through a double-cemented lens structure. This design effectively reduces the deviation and blurring of light of different wavelengths during imaging, ensuring that clear and color-accurate images can be presented within a large field of view range (such as a 40° field of view angle). Through the cooperation of the three imaging element groups, the eyepiece system of the present application realizes the perfect combination of high performance and compact structure, providing the observer with a clear, comfortable and multi-scene-adaptive visual experience.

[0103] Through the cooperative working mode of the above three imaging element groups, the eyepiece system of the present application realizes efficient correction of various aberrations, significantly reduces optical distortion, and can still maintain clear and high-quality imaging performance even in a larger field of view environment (such as a FOV of 40° or more).

[0104] Regarding the point spread function analysis, see Figure 5 and Figure 10 : the maximum image point is less than 37 μm. This indicates that the distribution of light on the image plane is highly concentrated, and the imaging clarity is significantly improved. This result verifies the precise control ability of the eyepiece system for light convergence.

[0105] Regarding the MTF performance, see Figure 6 and Figure 11 : the modulation transfer function (MTF) value is > 0.25 at a spatial frequency of 40 lp / mm, which indicates that the eyepiece system can still maintain excellent contrast transfer characteristics when high-resolution imaging is performed, ensuring that the image details are rich and distinct.

[0106] Regarding the optical distortion control, seeFigure 7 and Figure 12 The absolute value of optical distortion of the eyepiece system is less than 2%, which means that the image distortion is small, the object shape can be restored truly, and the high-precision observation requirement is met.

[0107] Regarding chromatic aberration correction, see Figure 1 and Figure 8 The maximum chromatic aberration value of the eyepiece system is less than 65pm, which effectively suppresses the image color deviation caused by the dispersion phenomenon, and ensures the authenticity and accuracy of color restoration.

[0108] The above performance indicators jointly prove that the eyepiece system of the present application realizes the breakthrough of comprehensive performance such as large field of view, high resolution, low distortion and low chromatic aberration through the new design of optical structure and the optimization of optical parameters, and provides the observer with clear, true and comfortable visual experience.

[0109] The eyepiece system of the present application adopts a folded optical path design, which utilizes the unique optical properties of the light splitting element 9 and the first optical functional film layer 10. The light splitting element 9 can partially reflect and partially transmit light, while the first optical functional film layer 10 further regulates light, so that light undergoes multiple reflections and refractions inside the eyepiece system. Through this complex and orderly light path folding, light can complete the transmission and imaging process from the image source to the human eye in a limited space.

[0110] Compared with the traditional straight-through optical scheme, the traditional scheme needs multiple lenses to be stacked in sequence to realize the transmission and imaging of light, resulting in a large volume of the formed eyepiece system, which occupies a large space. The folded optical path design of the eyepiece system provided by the present application effectively avoids this problem, realizing a more compact system volume. This compact optical structure design not only facilitates the miniaturization and portability of the device, but also provides more possibilities for the optimization of the device in other aspects, and is very suitable for scenes with extremely strict space requirements, such as portable observation devices, thereby improving the practicality and portability of the device.

[0111] It should be noted that the third lens 6 in the third imaging element group G3 provided by the present application has the function of moving along the optical axis to realize zooming. This feature not only enables the eyepiece system of the present application to adapt to the imaging requirements of objects of different distances and sizes, but also exhibits unique advantages in the adjustment and adaptation of myopia and hypermetropia.

[0112] When the third lens 6 moves along the optical axis towards the imaging surface, i.e. towards the first imaging element group G1, it changes the focal power of the eyepiece system. Just as a concave lens with a suitable power is used to correct myopia, by adjusting the position of the third lens 6 relative to the first imaging element group G1, light rays that would otherwise converge in front of the imaging surface are moved back and focused accurately on the imaging surface, allowing the observer to clearly see distant objects, effectively adapting to the imaging requirements in the case of myopia without the need for additional complex corrective lenses or components, simplifying the system structure.

[0113] When the third lens 6 moves along the optical axis away from the imaging surface, i.e. towards the second imaging element group G2, it increases the propagation path length of the light rays in the eyepiece system, while changing the refraction angle and convergence of the light rays. This is similar to using a convex lens to correct hyperopia, by this movement, the convergence ability of the eyepiece system to the light rays is enhanced, the light rays that would otherwise converge behind the imaging surface are moved forward and accurately fall on the imaging surface, allowing the observer to clearly observe the nearby objects, also in a simple way to achieve effective adaptation to the case of hyperopia.

[0114] The eyepiece system provided by the embodiments of the present application adopts a precise layout design from the image source side to the human eye side along the optical axis, and sequentially configures the second imaging element group G2, the third imaging element group G3 with dynamic zooming capability, and the first imaging element group G1 composed of the first lens 8 and the second lens 7 which are mutually glued. Among them, the third imaging element group G3 as the core zooming unit, integrates the light splitting element 9, the convex lens and the first optical function film layer 10 in which the first phase retarder 1001 and the polarization reflector 1002 are stacked. This group builds a folded light path through the synergistic effect of the light splitting element 9 and the first optical function film layer 10, while maintaining the compact structure of the system, significantly optimizing the optical transmission path.

[0115] The advantages of the eyepiece system of the present application can be manifested in three aspects: first, the movement mechanism of the third lens 6 along the optical axis can realize dynamic focal length adjustment for different observation distances (including myopia and hyperopia scenarios), giving the system flexible zooming capability; second, through the double-glued lens structure of the first imaging element group G1, combined with specific parameter conditions, the chromatic aberration in the large field of view environment is effectively corrected, ensuring the imaging clarity of 40° and above field of view; third, the folded light path design makes the overall length of the eyepiece system controlled within 52mm while realizing large field of view and high imaging quality, achieving the balance between miniaturization and high performance. Through optical architecture innovation, the eyepiece system realizes multiple technical breakthroughs in field of view expansion, imaging quality improvement and diopter adjustment in a limited volume.

[0116] In some examples of the present application, see Figure 1 and Figure 8, the third lens 6 is located in a folded optical path, both surfaces of the third lens 6 are convex, and an optical path L of the third lens 6 satisfies: L≥18mm, the optical path L is a product of a refractive index n3 of the third lens 6 and a central thickness T3 of the third lens 6 on an optical axis, and 12mm≤T3≤18mm.

[0117] In the examples provided in the present application, both surfaces of the third lens 6 are respectively provided with the light splitting element 9 and the first optical functional film layer 10, so that the third lens 6 is located in a folded optical path, see Figure 1 and Figure 8 .

[0118] The third lens 6 can adopt a double-convex surface design (that is, both surfaces of the third lens 6 are convex), and the optical path L can be calculated by the formula L=n3×T3 provided in the examples, where n3 is the refractive index of the material of the third lens 6, and T3 is the central thickness of the third lens 6 on the optical axis, also referred to as the central thickness of the third lens 6.

[0119] In the examples provided in the present application, the optical path L≥18mm, and the range of the central thickness T3 of the third lens 6 is optimized to be 12mm≤T3≤18mm. For example, when the refractive index n3 of the material of the third lens 6 is 1.5, the central thickness T3 needs to be≥12mm to meet the optical path requirement.

[0120] As a core component of the third imaging element group G3, the third lens 6 can move along the optical axis direction, and the system focal length can be changed by adjusting the lens position.

[0121] For the third lens 6, through the cooperative design of the double-convex surface design, the constraint of the optical path L, and the axial movement mechanism, the technical targets of diopter adjustment (±5D range), 40° field of view, and low optical distortion (<2%) are achieved in the system length of 45mm~52mm of the objective lens system of the present application, which is significantly superior to the volume and performance of the traditional objective lens.

[0122] In summary, the double-convex surface structure of the third lens 6 in the third imaging element group G3 cooperates with the folded optical path design to make the optical path complete multiple refraction and / or reflection in a limited space. The optical path L≥18mm ensures that the light is fully transmitted in the third lens 6 to maintain the imaging quality, and the total length of the entire objective lens system can be compressed to 45mm~52mm. Compared with the traditional straight-through objective lens (the length is usually >80mm), the optical design of the present application significantly reduces the volume while maintaining the 40° field of view and high imaging quality (MTF>0.25@40lp / mm).

[0123] In some examples of the present application, the third lens 6 is configured to provide power adjustment by moving along the optical axis, specifically as follows:

[0124] The third lens 6 moves towards the first imaging element group G1 to accommodate the myopic state.

[0125] The third lens 6 moves towards the second imaging element group G2 to accommodate the hyperopic state.

[0126] In this example provided by the present application, the third lens 6 achieves power adjustment by moving left and right along the optical axis to accommodate the myopic state and the hyperopic state respectively. This design ingeniously utilizes the optical principles and the effect of lens movement on the path of light propagation, which is explained below from the two states of myopia and hyperopia.

[0127] The third lens 6 moves towards the first imaging element group G1 to accommodate the myopic state.

[0128] Myopia is usually caused by the excessive length of the anterior-posterior diameter of the eyeball, or the excessive curvature of the lens that is not easily restored, resulting in the light reflected from a distant object being imaged in front of the retina after being refracted by the eyeball, rather than accurately falling on the retina, so that the myopic patient cannot see the distant object clearly. In an eyepiece system, simulating this situation means that the original convergence point of light from a distance (relative to the system) is in front of the imaging surface (simulating the retina).

[0129] The optical effect of the movement of the third lens 6 is that when the third lens 6 moves towards the first imaging element group G1, it changes the power distribution of the eyepiece system. The third lens 6 is equivalent to an element with specific optical properties, and its movement changes the refraction angle and path of light when passing through the lens. Specifically, when moving towards the first imaging element group G1, the third lens 6 enhances the divergence of light (because its position change affects the interaction of light and lens). This divergence is similar to wearing a suitable concave lens for myopic users to correct it, which can move the light that converges in front of the imaging surface backward, thereby accurately focusing the light on the imaging surface. In this way, the observer can clearly see the originally blurred distant objects, achieving accommodation for the myopic state.

[0130] The third lens 6 moves towards the second imaging element group G2 to accommodate the hyperopic state.

[0131] Hyperopia is caused by the shortness of the anterior-posterior diameter of the eyeball or the decrease in elasticity of the lens, resulting in the light reflected from a near object being refracted by the eyeball and then imaged behind the retina, so that the patient with hyperopia cannot see the near object clearly. In the eyepiece system of the present application, the corresponding situation is that the original convergence point of the light from the near object is behind the imaging surface.

[0132] The optical effect of the movement of the third lens 6: when the third lens 6 moves towards the second imaging element group G2, the change in its position changes the propagation path of the light in the eyepiece system. At this time, the converging effect of the third lens 6 on the light is relatively enhanced. It can move the light originally converged behind the imaging surface forward and then focus accurately on the imaging surface. This is like wearing a convex lens to correct the vision of a hyperopic user, which enhances the converging ability of the light so that the light from the near object can be clearly imaged on the retina (imaging surface).

[0133] This design of adjusting the diopter by moving the third lens 6 along the optical axis improves the versatility and adaptability of the eyepiece system. Without the need to replace lenses or complex optical components, it can meet the observation needs of users with different vision conditions (myopia and hyperopia) by simply moving the lens, reducing the cost and difficulty of operation. This design maintains the overall stability and optical performance of the eyepiece system, and does not significantly affect other optical parameters of the eyepiece system during the adjustment of the diopter, ensuring the stability of the imaging quality and providing the user with a clear and comfortable visual experience.

[0134] In some examples of the present application, the optical power of the third lens 6 φ3 satisfies: 0.004≤φ3≤0.005.

[0135] The third lens 6 is configured to be movable along the optical axis from an initial position to provide diopter adjustment by changing its relative position to the first imaging element group G1:

[0136] Moving 7mm to 9.5mm towards the first imaging element group G1 can achieve a diopter adjustment range of 0D to -5D;

[0137] Moving 7mm to 9.5mm towards the second imaging element group G2 can achieve a diopter adjustment range of 0D to +5D.

[0138] Wherein, at the initial position, the air gap P of the third lens 6 and the second lens 7 on the optical axis is: 9mm≤P≤10mm.

[0139] In the example of the present application, the optical power φ3 of the third lens 6 is designed to be in the range of 0.004 to 0.005 (φ3 includes the two end values 0.004 and 0.005). This specific range of optical power design is to match the folded optical path optical scheme adopted by the objective lens system of the present application. As the core element of the zoom group, the converging effect of the third lens 6 can accurately control the propagation direction and focusing position of the light, and form a synergistic effect with other lenses in the system to achieve the adjustment requirements of different myopia and hyperopia states.

[0140] For example, when correcting myopia, by adjusting the position of the third lens 6, the light originally converging in front of the imaging plane can be moved backward, thereby forming a clear image on the imaging plane.

[0141] The air gap P of the third lens 6 and the second lens 7 on the optical axis is designed to be between 9mm and 10mm. The setting of this air gap has a key influence on the overall performance of the objective lens system. If the air gap is too small (such as less than 9mm), it may cause interference and other adverse phenomena when the light propagates between the two lenses, thereby affecting the imaging quality; at the same time, too small gap will also limit the installation and adjustment space of the lens, increase the manufacturing difficulty. Conversely, if the air gap is too large (such as greater than 10mm), the volume of the objective lens system will increase, which does not meet the compact design requirement. Therefore, a suitable air gap can ensure that the light has enough space to transmit and optically adjust when propagating from the third lens 6 to the second lens 7, so as to ensure that the light can accurately enter the second lens 7 and follow the design requirements for subsequent refraction and focusing, and finally achieve clear and stable imaging effect.

[0142] In the example of the present application, the "initial position" has a clear definition, that is, when the observer's vision state is neither myopic nor hyperopic (the diopter adjustment is 0D), the position of the third lens 6. In this state, there is a specific air gap P between the third lens 6 and the second lens 7 in the first imaging element group G1. After optimization design, it is determined that the air gap P should meet the range requirement of 9mm≤P≤10mm.

[0143] In actual application, according to the specific design requirements and performance optimization direction, the air gap P of the third lens 6 and the second lens 7 on the optical axis can be set to different values, such as 9.1mm or 9.12mm, etc.

[0144] When the third lens 6 moves 7-9.5 mm towards the first imaging element group G1, the change of its position will change the refraction path of the light passing through the lens. Specifically, a 7 mm movement may correspond to a mild myopia correction requirement, suitable for cases with low myopia degree; while a 9.5 mm movement can achieve a 5D diopter adjustment, meeting the correction requirement of high myopia degree.

[0145] Similarly, when the third lens 6 moves 7-9.5 mm towards the second imaging element group G2, the change of its position will also affect the propagation path of the light in the system. A 7 mm movement may correspond to a mild hyperopia correction requirement, suitable for cases with low hyperopia degree; while a 9.5 mm movement can achieve a 5D diopter adjustment, meeting the correction requirement of high hyperopia degree.

[0146] This design makes the eyepiece system highly flexible and adaptable. By moving the third lens 6 along the optical axis by a limited distance, a wide range of diopter adjustment requirements from -5D to +5D can be covered, meeting the correction requirements of most myopia and hyperopia patients. At the same time, this adjustment method is relatively simple and reliable, without the need for complex mechanical structures or the replacement of multiple lenses, thereby reducing the cost and complexity of the eyepiece system and ensuring the stability and imaging quality of the system, providing a convenient and efficient visual correction solution for users.

[0147] In some examples of the present application, the refractive index difference |δ n | of the first lens 8 and the second lens 7 satisfies: 0.2≤|δ n |≤0.6, and the Abbe number difference |δ v | of the first lens 8 and the second lens 7 satisfies: 5≤|δ v |≤10; wherein the first lens 8 has positive optical power, the second lens 7 has negative optical power, the refractive index n2 of the second lens 7 is greater than the refractive index n1 of the first lens 8, and the Abbe number v2 of the second lens 7 is less than the Abbe number v1 of the first lens 8.

[0148] In examples of the present application, the optical properties of the first lens 8 and the second lens 7 in the first imaging element group G1 are optimally designed. Specifically, the refractive index difference |δ n | of the two lenses is controlled within the range of 0.2-0.6 (|δ n | includes the two end values 0.2 and 0.6), and the Abbe number difference |δ v | is controlled within the range of 5-10 (|δ v | includes the two end values 5 and 10). Wherein, see Figure 2 andFigure 2 The first lens 8 is designed to have positive optical power, and the second lens 7 is designed to have negative optical power. On the basis of the optical power design, the refractive index n2 of the second lens 7 is greater than the refractive index n1 of the first lens 8, and the Abbe number v2 of the second lens 7 is less than the Abbe number v1 of the first lens 8. The first imaging element group G1 thus formed mainly undertakes the task of correcting chromatic aberration at a large field of view in the eyepiece system.

[0149] Chromatic aberration is a common aberration in optical systems, which causes light rays of different wavelengths to not be focused on the same point when imaging, thereby affecting the imaging quality. In order to effectively correct chromatic aberration, the optical parameters of the lenses need to be reasonably designed.

[0150] In this application, by precisely controlling the refractive index difference |δ n | and the Abbe number difference |δ v | of the first lens 8 and the second lens 7, combining their respective optical power characteristics (one positive and one negative), and the relative size relationship of the refractive index and the Abbe number, such as n2>n1 and v2

[0151] This example in the application realizes efficient correction of chromatic aberration at a large field of view by precisely limiting and optimizing the optical characteristics of the first lens 8 and the second lens 7, and improves the overall imaging quality of the eyepiece system.

[0152] In some examples of the application, referring to Figure 1 The first phase retarder 1001 is located on the optical path between the light splitting element 9 and the polarized reflector 1002; and the first optical functional film layer 10 further includes a first polarizer 1003, which is stacked on the side surface of the polarized reflector 1002 away from the first phase retarder 1001.

[0153] The first polarizer 1003, such as a polarizing film, can selectively transmit or reflect light vibrations in a specific direction.

[0154] In the eyepiece system of the application, by introducing the first polarizer 1003 and arranging it on the side of the polarized reflector 1002 away from the first phase retarder 1001, this design can reduce the interference of stray light.

[0155] Specifically, stray light is usually unwanted light generated by the reflection, scattering or refraction of light on the interface. By placing the first polarizer 1003 on the side of the polarization reflector 1002 away from the first phase retarder 1001, stray light that is not consistent with the direction of the main light can be filtered out, reducing their interference with the imaging quality. This helps to improve the contrast and clarity of the image, making it more realistic and immersive for users to view virtual images.

[0156] The reduction of stray light directly improves the imaging quality. In virtual reality applications, high-contrast and high-clarity images are the basis for providing a high-quality visual experience. The introduction of the first polarizer 1003 enables the system to better control the propagation direction and state of light, reducing unnecessary light interference, thereby improving the overall presentation of the image.

[0157] In addition to directly improving image quality, the introduction of the first polarizer 1003 also helps to improve the overall efficiency of the optical module. By reducing the propagation and energy loss of stray light, the eyepiece system can more efficiently utilize light energy and concentrate more energy on the imaging process.

[0158] In this example of the present application, the first phase retarder 1001, the polarization reflector 1002 and the first polarizer 1003 are stacked in sequence to form the first optical functional film layer 10. By stacking multiple optical elements together, a highly integrated composite optical film material is formed, which not only simplifies the structure of the eyepiece system, but also significantly reduces the volume of the eyepiece system.

[0159] The close arrangement of the elements in the first optical functional film layer 10 helps to optimize the propagation path of light, reducing energy loss and aberration when light is transmitted between elements. In particular, the close cooperation of the first phase retarder 1001 with the first polarizer 1003 and the polarization reflector 1002 allows for more precise control of the polarization state and reflection direction of light, thereby improving the imaging quality.

[0160] Traditional optical modules require the installation and adjustment of each element one by one, while the design of the first optical functional film layer 10 simplifies the assembly process, allowing the composite film material to be installed as a whole unit into the system, thereby improving production efficiency.

[0161] Optionally, referring to Figure 8 A first anti-reflection film 1004 can also be introduced into the first optical functional film layer 10, which can reduce the reflection of light on the lens surface, thereby increasing the transmittance of light. This not only improves the brightness of the image, but also improves the overall optical performance of the eyepiece system.

[0162] In some examples of the present application, referring toFigure 1 and Figure 8 The second imaging element group G2 includes, in order from the image source side to the human eye side along the optical axis, a sixth lens 3, a fifth lens 4, and a fourth lens 5. The optical power φ G2 satisfies: 0.015 ≤ φ G2 ≤ 0.025.

[0163] The second imaging element group G2 adopts a design of at least two lenses. For example, three lenses are adopted in this example: the fourth lens 5, the fifth lens 4, and the sixth lens 3. This is to better achieve performance optimization of the eyepiece system. Different lenses have different optical properties, such as curvature, thickness, material, etc. By reasonably combining multiple lenses, the advantages of each lens can be brought into play to improve imaging quality.

[0164] Specifically, the second imaging element group G2 provided in this example is configured with the sixth lens 3, the fifth lens 4, and the fourth lens 5 in order from the image source side to the human eye side along the optical axis direction, ensuring the stability of light transmission and imaging quality.

[0165] Further, the optical power φ G2 of the second imaging element group G2 is also optimized, i.e., its value needs to satisfy the range of 0.015 to 0.025 (φ G2 including the two end values 0.015 and 0.025). This setting is based on in-depth consideration of the overall performance of the eyepiece system, aiming to achieve efficient aberration correction by controlling the optical power of the second imaging element group G2, thereby improving the imaging quality of the eyepiece system.

[0166] In this application, the role of the second imaging element group G2 is to correct aberrations to improve the image quality of the eyepiece system. Aberration is an important factor affecting the clarity of imaging in optical systems, including but not limited to spherical aberration, coma, astigmatism, field curvature, and distortion, etc. By reasonably designing the optical power of the second imaging element group G2, these aberrations can be effectively reduced, making the imaging clearer and more accurate.

[0167] For example, the optical power φ G2 of the second imaging element group G2 is set to 0.021 or 0.016.

[0168] In addition, the number of lenses in the second imaging element group G2 should not be less than 2. This requirement ensures that the second imaging element group G2 has sufficient optical adjustment capability to deal with aberration problems under different fields of view and wavelengths. In the example provided in this application, by configuring three lenses (the sixth lens 3, the fifth lens 4, and the fourth lens 5), the second imaging element group G2 not only maintains the compactness of the system, but also achieves efficient aberration correction and improvement of imaging quality.

[0169] The second imaging element group G2 provided by the present application is arranged in the order of the sixth lens 3, the fifth lens 4 and the fourth lens 5 from the image source side to the human eye side along the optical axis: this specific arrangement order is the result of optical design and optimization. The image source side is the starting point of the light entering the second imaging element group G2, and the human eye side is the final position of the light. Arranging the sixth lens 3, the fifth lens 4 and the fourth lens 5 in this order can properly regulate the light when passing through each lens, ensuring that the light can be accurately focused on the retina of the human eye in the subsequent process, forming a clear image.

[0170] In some examples of the present application, the combined optical power φ t satisfies: 0.015 ≤ φ t ≤ 0.025.

[0171] In examples of the present application, the combined optical power φ t of the second imaging element group G2 and the third imaging element group G3 is optimized, i.e. its value needs to satisfy the range of 0.015 to 0.025 (φ t including the two end values 0.015 and 0.025). This aims to achieve the reduction of the focal length and the increase of the magnification of the eyepiece system by controlling the combined optical power of the two groups of elements.

[0172] Specifically, the second imaging element group G2 is mainly responsible for aberration correction. The third imaging element group G3, as the zoom group of the eyepiece system, has the ability to move along the optical axis direction, and by adjusting its position, it can realize the adjustment of the system to different myopia and hyperopia conditions, and is the key part of the eyepiece system to realize the zoom function. Controlling the combined optical power of the second imaging element group G2 and the third imaging element group G3 to be 0.015 to 0.025 can effectively balance the aberration correction ability and zoom ability of the eyepiece system. The setting of this combined optical power helps to reduce the overall focal length of the eyepiece system while maintaining the imaging quality of the eyepiece system.

[0173] Through such design, the focal length of the eyepiece system of the present application can be reduced to not more than 31.5 mm, which greatly enhances the compactness and portability of the system.

[0174] At the same time, in addition to reducing the focal length, it also brings the effect of increasing the magnification of the eyepiece system. The increase of the magnification means that the system can present larger and clearer images, which is particularly important for application scenarios that require high-resolution imaging.

[0175] In some examples of the present application, the total effective focal length F of the eyepiece system satisfies: 30 mm ≤ F ≤ 32 mm.

[0176] The effective focal length F can balance the reasonable imaging size and clarity of the eyepiece system, ensure sufficient field of view, make the imaging clear and sharp, and adapt to different image sources, thereby improving the overall performance and use experience of the eyepiece system.

[0177] In some examples of the present application, referring to Figure 1 and Figure 3 , the eyepiece system further comprises a display screen 1 arranged on the image source side of the second imaging element group G2.

[0178] The eyepiece system provided by the embodiments of the present application is provided with a protective glass 2 on the light-emitting surface of the display screen 1. Specifically, the protective glass 2 in front of the display screen 1 can effectively isolate dust, fingerprints and other dirt from the outside, thereby keeping the surface of the display screen 1 clean. This is crucial for optical modules, because any dirt on the screen surface can affect light transmission and image quality. By introducing a protective glass 2 with a certain thickness, the tolerance of the eyepiece system to dirt on the surface of the display screen 1 is significantly improved, ensuring the stability and reliability of the optical module.

[0179] The protective glass 2 not only can isolate dirt, but also can effectively prevent the display screen 1 from being scratched, collided and other physical damage. This is of great significance to prolong the service life of the display screen 1 and improve the overall durability of the device.

[0180] In some examples of the present application, the eyepiece system further comprises a second optical functional film layer 11, referring to Figure 1 and Figure 8 , the second optical functional film layer 11 comprises a second phase retarder 1101, a second polarizer 1102 and a third phase retarder 1103 stacked in sequence from the image source side to the human eye side. The second optical functional film layer 11 is arranged on one side surface of the fourth lens 5 close to the third imaging element group G3, referring to Figure 3 and Figure 1 .

[0181] Among them, the second phase retarder 1101 and the third phase retarder 1103 are both quarter-wave plates. The second polarizer 1102 is a polarizing film.

[0182] Optionally, referring to Figure 8 , a second anti-reflection film 1104 can also be introduced in the second optical functional film layer 11. The arrangement of the second anti-reflection film 1104 can reduce the reflection of light on the lens surface, thereby increasing the transmittance of light. This not only can improve the brightness of the image, but also can improve the overall optical performance of the optical system.

[0183] In the examples provided in the present application, the display screen 1 is configured to emit circularly polarized light or natural light. In the case where the display screen 1 emits natural light, a second optical functional film layer 11 can be provided on the light emitting surface of the display screen 1 to convert the natural light into circularly polarized light.

[0184] In some examples of the present application, the optical power φ1 of the first lens 8 is 0.008≤φ1≤0.01. The optical power φ2 of the second lens 7 is -0.02≤φ2≤-0.01.

[0185] In the first imaging element group G1, the positive optical power of the first lens 8 (with an optical power φ1 satisfying 0.008≤φ1≤0.01) is matched with the negative optical power of the second lens 7 (with an optical power φ2 satisfying -0.02≤φ2≤-0.01), and the optical power ranges of the two are reasonably set. Such a combination of positive and negative optical powers can effectively compensate for aberrations and balance the convergence and divergence of light rays. Through such a design, the first imaging element group G1 can better focus light rays.

[0186] In some examples of the present application, the optical power φ4 of the fourth lens 5 is 0.002≤φ4≤0.005. The optical power φ5 of the fifth lens 4 is -0.05≤φ5≤-0.01. The optical power φ6 of the sixth lens 3 is 0.02≤φ6≤0.06.

[0187] In the examples of the present application, the positive optical power of the fourth lens 5 (0.002≤φ4≤0.005) is complementary to the negative optical power of the fifth lens 4 (-0.05≤φ5≤-0.01), effectively correcting on-axis aberrations, while the positive optical power of the sixth lens 3 (0.02≤φ6≤0.06) further balances the system optical power distribution. The three work together to significantly improve the aberration correction ability of the second imaging element group G2, ensuring that the imaging quality is optimized after the light rays are transmitted through the three lenses.

[0188] In some examples of the present application, referring to Figure 1 and Figure 8 , the surface of the sixth lens 3 close to the eye side is convex, and the convex surface has at least one inflection point.

[0189] From Figure 1 and Figure 8 , the surface of the sixth lens 3 close to the eye side (i.e. Figure 1 and Figure 2The twelfth surface 32 shown is designed as a convex surface with at least one inflection point. This inflection point design has significant advantages: it optimizes the curvature distribution of the lenses, enhancing aberration correction capabilities while maintaining system compactness. In particular, it allows for more precise control of light deflection over a wide field of view, effectively controlling distortion and improving the imaging quality of the edge fields of view. This structural design is highly compatible with the aberration correction function of the second imaging element group G2, and together with the optical power combination of other lenses, it optimizes the imaging quality of the eyepiece system.

[0190] In some examples of this application, the total optical length (TTL) of the eyepiece system satisfies: 45mm ≤ TTL ≤ 52mm.

[0191] The eyepiece system provided in this application embodiment can achieve a shorter overall optical length in a field of view of, for example, 40° or even larger, which effectively controls the size of the eyepiece system.

[0192] The eyepiece system provided in this application embodiment has the following refractive index: n and dispersive system v The range is: 1.4 < n <2.0, 20< v <90.

[0193] The eyepiece system provided in this application embodiment has a center thickness range of 1mm ≤ T ≤ 12mm for the sixth lens 3, the fifth lens 4, and the fourth lens 5. Each of these three lenses contains two surfaces, which can be aspherical or spherical, and their surfaces can be provided with an anti-reflective coating.

[0194] The eyepiece system provided in this application embodiment has a third lens 6 with a center thickness T3 ranging from 12mm to 18mm. The third lens 6 includes two surfaces, a fifth surface 61 and a sixth surface 62, which can be aspherical or planar. A first optical functional film layer 10 is provided on the sixth surface 62, and a beam splitter 9 is provided on the fifth surface 61.

[0195] The eyepiece system provided in this application embodiment has a center thickness T2 of the second lens 7 in the range of 1mm≤T2≤12mm. The second lens 7 includes two surfaces, namely a third surface 71 and a fourth surface 72. These two surfaces can be aspherical or spherical, and their surfaces can be provided with an anti-reflective coating.

[0196] The eyepiece system provided by the embodiments of the present application, wherein the central thickness T1 of the first lens 8 ranges from 5mm to 10mm, the first lens 8 comprises two surfaces, i.e. the first surface 81 and the second surface 82, and the two surfaces can be aspherical or spherical, and the surfaces can be provided with an anti-reflection film layer. Moreover, the first surface 81 of the first lens 8 is cemented with the fourth surface 72 of the second lens 7.

[0197] The eyepiece system provided by the present application is described below by way of Example 1 and Example 2 respectively.

[0198] Example 1

[0199] The eyepiece system provided by the embodiments of the present application, wherein the central thickness T1 of the first lens 8 ranges from 5mm to 10mm, the first lens 8 comprises two surfaces, i.e. the first surface 81 and the second surface 82, and the two surfaces can be aspherical or spherical, and the surfaces can be provided with an anti-reflection film layer. Moreover, the first surface 81 of the first lens 8 is cemented with the fourth surface 72 of the second lens 7. Figure 1

[0200] The display screen 1;

[0201] The second imaging element group G2 comprises the sixth lens 3, the fifth lens 4 and the fourth lens 5 arranged in sequence from the image source side to the human eye side along the optical axis;

[0202] The third imaging element group G3 comprises the third lens 6 which can move along the optical axis, the surface of the third lens 6 close to the image source side is a convex surface and is provided with the light splitting element 9, and the surface close to the human eye side is also a convex surface and is provided with the first optical function film layer 10; and

[0203] The first imaging element group G1 comprises the second lens 7 and the first lens 8 arranged in sequence from the image source side to the human eye side and cemented with each other;

[0204] The first optical function film layer 10 comprises the first anti-reflection film 1004, the first phase retarder 1001, the polarized reflector 1002 and the first polarizer 1003 arranged in sequence, as shown in Figure 3 The eyepiece system further comprises the second optical function film layer 11, which is arranged on the side surface of the fourth lens 5 close to the third imaging element group, i.e. the eighth surface 52 shown in

[0205] Figure 4 to Figure 7 The second optical function film layer 11 comprises the second phase retarder 1101, the second polarizer 1102, the third phase retarder 1103 and the second anti-reflection film 1104 arranged in sequence from the image source side to the human eye side, as shown in Figure 4

[0206] When the observer is neither myopic nor hyperopic, i.e. the exact setting of the diopter adjustment is 0D, the air gap P between the third surface 71 of the second lens 7 and the sixth surface 62 of the third lens 6 is 10mm; ​​​

[0207] When the observer needs to adapt -5D, the third lens 6 is configured to move along the optical axis to the first imaging element group G1, so that the air gap P between the third surface 71 of the second lens 7 and the sixth surface 62 of the third lens 6 is 6.4mm;

[0208] When the observer needs to adapt 5D, the third lens 6 is configured to move along the optical axis to the second imaging element group G2, so that the air gap P between the third surface 71 of the second lens 7 and the sixth surface 62 of the third lens 6 is 12.8mm;

[0209] The refractive index of the first lens 8 is n 1 is 1.67, and the dispersion coefficient v1 is 32;

[0210] The refractive index of the second lens 7 is n 2 is 1.91, and the dispersion coefficient v2 is 25;

[0211] The refractive index of the third lens 6 is n 3 is 1.55, and the dispersion coefficient v3 is 56;

[0212] The refractive index of the fourth lens 5 is n 4 is 1.65, and the dispersion coefficient v4 is 21.5;

[0213] The refractive index of the fifth lens 4 is n 5 is 1.53, and the dispersion coefficient v5 is 56;

[0214] The refractive index of the sixth lens 3 is n 6 is 1.53, and the dispersion coefficient v6 is 56.

[0215] The total effective focal length of the eyepiece system provided in Embodiment 1 is 31.5mm;

[0216] The total optical length of the eyepiece system provided in Embodiment 1 is 51.7mm.

[0217] The optical parameters of each lens in Embodiment 1 are shown in Table 1 below.

[0218] Table 1

[0219]

[0220] The optical power of the five lenses in Embodiment 1 is shown in Table 2 below.

[0221] Table 2

[0222]

[0223] The optical performance of the eyepiece system provided in Embodiment 1 is as followsFigure 5 As shown: Figure 6 It is a dot array diagram. Figure 7 It is an MTF curve. Figure 4 to Figure 7 This is a diagram of the curvature and distortion. Figure 4 This is a vertical axis chromatic aberration diagram. The following is about... Figure 5 Analysis:

[0224] See Figure 6 The eyepiece system provided in this embodiment 1 has a maximum image size of less than 37μm in the dot matrix diagram.

[0225] See Figure 7 The eyepiece system provided in this embodiment 1 has an MTF > 0.3 at 40 lp / mm.

[0226] See Figure 1 The eyepiece system provided in this embodiment has the maximum distortion occurring in the field of view of 1, with an absolute value of less than 2%.

[0227] See Figure 8 The eyepiece system provided in this embodiment 1 has a maximum chromatic difference value of less than 37μm.

[0228] See Figure 2 The light path diagram shown shows that the light emitted from the display screen 1 is transmitted through the protective glass 2, the sixth lens 3, the fifth lens 4, and the fourth lens 5. After passing through the second optical functional film layer 11 on the eighth surface 52 of the fourth lens 5, the light becomes circularly polarized light. After passing through the third lens 6, it becomes linearly polarized light (such as S-polarized light) after passing through the first phase delay 1001 on the sixth surface 62 of the third lens 6. After being reflected by the polarizing reflector 1002, it becomes circularly polarized light again after passing through the first phase delay 1001. After being reflected by the beam splitter 9 on the fifth surface 61 of the third lens 6, it becomes linearly polarized light (P-polarized light) after passing through the first phase delay 1001 for the third time. It is then transmitted through the second lens 7 and the first lens 8 and enters the human eye 01.

[0229] Example 2

[0230] The eyepiece system provided in this embodiment 2 is described in [reference]. Figure 8 Along the optical axis from the image source side to the human eye side, it includes, in sequence:

[0231] Display screen 1;

[0232] The second imaging element group G2 includes a sixth lens 3, a fifth lens 4 and a fourth lens 5 arranged sequentially along the optical axis from the image source side to the human eye side;

[0233] The third imaging element group G3 includes a third lens 6 movable along the optical axis. The surface of the third lens 6 near the image source is convex and has a beam splitter 9, while the surface near the human eye is also convex and has a first optical functional film layer 10.

[0234] The first imaging element group G1 includes a second lens 7 and a first lens 8 arranged sequentially from the image source side to the human eye side and glued together;

[0235] See Figure 3 The first optical functional film layer 10 includes a first anti-reflection film 1004, a first phase retarder 1001, a polarizing reflector 1002 and a first polarizer 1003, which are stacked sequentially.

[0236] The eyepiece system further includes a second optical functional coating layer 11, which is disposed on the side surface of the fourth lens 5 near the third imaging element group (i.e., Figure 9 to Figure 12 On the eighth surface 52 shown in the figure; wherein, the second optical functional film layer 11 includes a second phase retarder 1101, a second polarizer 1102, a third phase retarder 1103 and a second anti-reflection film 1104 stacked sequentially from the image source side to the human eye side, see Figure 9 .

[0237] When the observer is neither nearsighted nor farsighted, that is, when the diopter adjustment is precisely set to 0D, the air gap P between the third surface 71 of the second lens 7 and the sixth surface 62 of the third lens 6 is 12.7mm.

[0238] When the observer needs to adapt to -5D, the third lens 6 is configured to move along the optical axis to the first imaging element group G1 so that the air gap P between the third surface 71 of the second lens 7 and the sixth surface 62 of the third lens 6 is 7.2 mm.

[0239] When the observer needs to adapt to 5D, the third lens 6 is configured to move along the optical axis to the second imaging element group G2 so that the air gap P between the third surface 71 of the second lens 7 and the sixth surface 62 of the third lens 6 is 15.8 mm.

[0240] The refractive index of the first lens 8 n 1 is 1.67, and the dispersion coefficient v1 is 32;

[0241] The refractive index of the second lens 7 n 2 is 1.85, and the dispersion coefficient v2 is 24;

[0242] The refractive index of the third lens 6 n 3 is 1.55, and the dispersion coefficient v3 is 56;

[0243] The refractive index of the fourth lens 5 n The value of 4 is 1.65, and the dispersion coefficient v4 is 21.5;

[0244] The refractive index of the fifth lens 4 n 5 is 1.53, and the Abbe number v5 is 56;

[0245] The refractive index of the sixth lens 3 n 6 is 1.53, and the Abbe number v6 is 56.

[0246] The total effective focal length of the eyepiece system provided in Embodiment 2 is 31.5 mm.

[0247] The total optical length of the eyepiece system provided in Embodiment 2 is 51.5 mm.

[0248] The optical parameters of each lens in Embodiment 2 are shown in Table 3 below.

[0249] Table 3

[0250]

[0251] The optical powers of the six lenses in Embodiment 2 are shown in Table 4 below.

[0252] Table 4

[0253]

[0254] The optical performance of the eyepiece system provided in Embodiment 2 is shown in Figure 10 : Figure 11 is a schematic diagram of a spot diagram, Figure 12 is a diagram of MTF curves, Figure 9 to Figure 12 is a diagram of field curvature and distortion, Figure 9 is a diagram of axial chromatic aberration. The following analyzes Figure 10 :

[0255] Referring to Figure 11 , the maximum value of the image point in the spot diagram of the eyepiece system provided in Embodiment 2 is less than 17 μm.

[0256] Referring to Figure 12 , the MTF of the eyepiece system provided in Embodiment 2 is >0.1 at 40 lp / mm.

[0257] Referring to Figure 2 , the maximum distortion of the eyepiece system provided in Embodiment 2 occurs at 1 field of view, and the absolute value is less than 2%.

[0258] Referring to ​ , the maximum chromatic aberration value of the eyepiece system provided in Embodiment 2 is less than 37 m.

[0259] Referring to ​The light path diagram shows that the light emitted by the display screen 1 is transmitted through the surface protection glass 2, the sixth lens 3, the fifth lens 4 and the fourth lens 5, becomes circularly polarized light after passing through the second optical function film layer 11 on the eighth surface 52 of the fourth lens 5, becomes linearly polarized light (such as S polarized light) after passing through the third lens 6 and the first phase retarder 1001 on the sixth surface 62 of the third lens 6, is reflected by the polarized reflector 1002, becomes circularly polarized light again after passing through the first phase retarder 1001, is reflected by the light splitting element 9 on the fifth surface 61 of the third lens 6, becomes linearly polarized light (P polarized light) for the third time after passing through the first phase retarder 1001, is transmitted through the second lens 7 and the first lens 8, and enters the human eye 01.

[0260] According to another embodiment of the present application, there is provided an optical device comprising the eyepiece system as described above and an objective lens system.

[0261] The eyepiece system provided by the embodiments of the present application is suitable for optical devices such as sighting devices.

[0262] The specific implementation of the optical device of the embodiments of the present application can refer to the above-mentioned embodiments of the eyepiece system, and therefore has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described here in detail.

[0263] The above embodiments mainly describe the differences between the embodiments, and the different optimization features between the embodiments can be combined to form a better embodiment as long as they are not contradictory. In view of the brevity of the writing, this will not be described here in detail.

[0264] Although some specific embodiments of the present application have been described in detail by examples, those skilled in the art should understand that the above examples are only for illustration and are not intended to limit 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. An eyepiece system, characterized in that, Along the optical axis from the image source side to the human eye side, the following are included in sequence: The second imaging element group (G2) includes at least two lenses; The third imaging element group (G3) includes a third lens (6) movable along the optical axis. At least one of the two surfaces of the third lens (6) is convex. A beam splitter (9) is disposed on the surface near the image source, and a first optical functional film layer (10) is disposed on the surface near the human eye. The first optical functional film layer (10) includes a first phase retarder (1001) and a polarizing reflector (1002) stacked sequentially. The first imaging element group (G1) includes a second lens (7) and a first lens (8) arranged sequentially from the image source side to the human eye side and glued together, and the first lens (8) and the second lens (7) satisfy the relationship: 0.02≤(1 / R)*|δ n |*|δ v |≤0.03, where R is the radius of curvature of the bonding surface between the first lens (8) and the second lens (7), δ n δ is the refractive index difference between the first lens (8) and the second lens (7). v The difference in Abbe number between the first lens (8) and the second lens (7) is given.

2. The eyepiece system according to claim 1, characterized in that, The third lens (6) is located in the folded optical path. Both surfaces of the third lens (6) are convex, and the optical path L of the third lens (6) satisfies: L≥18mm. The optical path L is the product of the refractive index n3 of the third lens (6) and its center thickness T3 on the optical axis, where 12mm≤T3≤18mm.

3. The eyepiece system according to claim 1, characterized in that, The third lens (6) is configured to provide diopter adjustment by moving along the optical axis: Move toward the first imaging element group (G1) to adapt to the myopic state; It moves toward the second imaging element group (G2) to adapt to the farsighted state.

4. The eyepiece system according to claim 3, characterized in that, The optical power of the third lens (6) is φ3, which satisfies the following condition: 0.004≤φ3≤0.005; The third lens (6) is configured to move along the optical axis from an initial position to provide diopter adjustment by changing its relative position to the first imaging element group (G1): Moving the lens towards the first imaging element group (G1) by 7mm to 9.5mm enables a diopter adjustment range of 0D to -5D. Moving the lens toward the second imaging element group (G2) by 7mm to 9.5mm enables a diopter adjustment range of 0D to +5D. At the initial position, the air gap P between the third lens (6) and the second lens (7) on the optical axis is: 9mm≤P≤10mm.

5. The eyepiece system according to claim 1, characterized in that, The refractive index difference between the first lens (8) and the second lens (7) |δ n | Satisfies: 0.2 ≤ |δ n |≤0.6, the Abbe number difference between the first lens (8) and the second lens (7)|δ v | Satisfies: 5 ≤ |δ v |≤10; The first lens (8) has positive optical power, the second lens (7) has negative optical power, the refractive index n2 of the second lens (7) is greater than the refractive index n1 of the first lens (8), and the Abbe number v2 of the second lens (7) is less than the Abbe number v1 of the first lens (8).

6. The eyepiece system according to claim 1, characterized in that, The first phase delayer (1001) is located between the beam splitter (9) and the polarizing reflector (1002); The first optical functional film layer (10) also includes a first polarizer (1003), which is stacked on the side surface of the polarizing reflector (1002) away from the first phase delayer (1001).

7. The eyepiece system according to claim 1, characterized in that, The second imaging element group (G2) includes a sixth lens (3), a fifth lens (4) and a fourth lens (5) arranged sequentially along the optical axis from the image source side to the human eye side; The optical power φ of the second imaging element group (G2) G2 Satisfies: 0.015≤φ G2 ≤0.

025.

8. The eyepiece system according to claim 1, characterized in that, The combined optical power φ of the second imaging element group (G2) and the third imaging element group (G3) t Satisfies: 0.015≤φ t ≤0.

025.

9. The eyepiece system according to claim 8, characterized in that, The total effective focal length F of the eyepiece system satisfies: 30mm≤F≤32mm.

10. The eyepiece system according to claim 1, characterized in that, The eyepiece system also includes a display screen (1) disposed on the image source side of the second imaging element group (G2).

11. The eyepiece system according to claim 7, characterized in that, The eyepiece system also includes a second optical functional film layer (11), which includes a second phase retarder (1101), a second polarizer (1102) and a third phase retarder (1103) stacked sequentially from the image source side to the human eye side. The second optical functional film layer (11) is disposed on the side surface of the fourth lens (5) near the third imaging element group (G3).

12. The eyepiece system according to claim 1 or 5, characterized in that, The optical power φ1 of the first lens (8) is 0.008≤φ1≤0.01; The optical power φ2 of the second lens (7) is -0.02≤φ2≤-0.

01.

13. The eyepiece system according to claim 7, characterized in that, The optical power φ4 of the fourth lens (5) is 0.002≤φ4≤0.005; The optical power φ5 of the fifth lens (4) is -0.05≤φ5≤-0.01; The optical power φ6 of the sixth lens (3) is 0.02≤φ6≤0.

06.

14. The eyepiece system according to claim 7, characterized in that, The surface of the sixth lens (3) near the human eye is convex, and the convex surface has at least one inflection point.

15. An optical device, characterized in that, include: The eyepiece system as described in any one of claims 1-14; as well as, Objective lens system.

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