Optical lens and optical display device

Abstract

The embodiment of the invention provides an optical lens and optical display equipment. The optical lens sequentially comprises a first group, a second group, a third group, a fourth group and an imaging chip group from an imaging side to an image source side along an optical axis, the first group is a doublet lens group and comprises two glass spherical lenses, the first lens is a positive lens, and the second lens is a negative lens; the second group comprises at least two lenses; the third group comprises at most one glass spherical lens with positive focal power; the fourth group comprises at least one plastic aspheric lens with negative focal power; the imaging chip group is arranged on the side closest to an image source.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of optical imaging, and more particularly, to an optical lens and an optical display device. BACKGROUND

[0002] With the rapid development of artificial intelligence technology, AR glasses, as a highly potential intelligent display carrier, are gradually moving towards practicality. As the core optical component of AR glasses, the optical lens is responsible for transmitting the information of the image processing chip to the optical waveguide device, and its performance directly determines the user's visual experience.

[0003] At present, the field of view (FOV) of AR lenses on the market is mostly concentrated in about 30°, resulting in poor immersion of users. Although the optical waveguide technology can support a larger FOV, the optical lens matched therewith still has technical challenges to maintain a large FOV, high resolution, low aberration and controllable cost. Common optical lens architectures often face difficulties in aberration (such as chromatic aberration, field curvature, distortion) correction, excessive system size or cost, etc. when achieving a large FOV.

[0004] Therefore, there is an urgent need in the art for an optical lens that can achieve a large FOV and high imaging quality under the premise of ensuring a compact structure and reasonable cost. SUMMARY

[0005] The purpose of the present application is to provide a new technical solution for an optical lens and an optical display device to solve the problem of small field of view, poor immersion, and difficulty in balancing cost and performance of AR optical lenses in the prior art.

[0006] In a first aspect, embodiments of the present application provide an optical lens, which comprises, in order along an optical axis from an imaging side to an image source side: a first group, which is a double-cemented lens group, and contains two glass spherical lenses, wherein the first lens is a positive lens and the second lens is a negative lens; a second group, which contains at least two lenses and contains a positive lens and a negative lens; a third group, which contains at most one glass spherical lens with positive optical power; a fourth group, which contains at least one plastic aspherical lens with negative optical power; and an imaging chip group, which is arranged closest to the image source side.

[0007] Optionally, the first lens is a double-convex lens, and the refractive index Nd 101 satisfies 1.80 < Nd 101 < 1.85, and the Abbe number Vd 101 > 40; The second lens is a double-concave lens, and its refractive index Nd 102 <1.65, and Abbe number Vd 102 <34.

[0008] Optionally, the focal length f1 of the first lens satisfies: 5.3mm≤f1≤5.7mm. The focal length f2 of the second lens satisfies: -9.0mm≤f2≤-9.6mm.

[0009] Optionally, the second group is a double-cemented lens group, which comprises a third lens and a fourth lens cemented with each other, and the third lens and the fourth lens are both glass spherical lenses; wherein the third lens is a double-concave negative lens, and the fourth lens is a double-convex positive lens.

[0010] Optionally, the second group is composed of two single lenses arranged at intervals, and at most one of them is a glass aspherical lens. The two single lenses comprise a third lens and a fourth lens, wherein: The third lens is a negative lens, and the surface close to the first group is concave; The fourth lens is a positive lens, and the surface close to the imaging chip group is convex.

[0011] Optionally, the refractive index Nd of the negative lens in the second group satisfies: Nd<1.65, and Abbe number Vd<34. The refractive index Nd of the positive lens in the second group satisfies: 1.71<Nd<1.85, and Abbe number Vd>40.

[0012] Optionally, the focal length f3 of the negative lens in the second group satisfies: -4.5mm≤f3≤-5.5mm. The focal length f4 of the positive lens in the second group satisfies: 5mm≤f4≤6mm.

[0013] Optionally, the third group comprises a fifth lens, which is a double-convex glass spherical lens, and the focal length f5 of the fifth lens satisfies: 11.0mm≤f5≤11.5mm.

[0014] Optionally, the fourth group comprises a sixth lens, which is a plastic aspherical lens, at least one surface of which is aspherical, and the focal length f6 of the sixth lens satisfies: -9mm≤f6≤-8mm. The minimum air gap between the sixth lens and the imaging chip group is 0.3mm~0.5mm.

[0015] Optionally, the aspherical surface of the aspherical lens is an even aspherical surface, and the sag of the aspherical surface is defined by the following formula: ; wherein z is the surface sag, c is the reciprocal of the curvature radius, k is the conic constant, and a1-a8 are even-order aspheric coefficients.

[0016] Optionally, the focal length f of any lens in the optical lens satisfies: 0.5 i and the total focal length F of the optical lens satisfies: 0.56 i / F|≤1.5; wherein the total focal length F of the optical lens satisfies: 7.9mm

[0017] Optionally, the total length TTL of the optical lens satisfies: TTL≤13.5mm.

[0018] Optionally, the total length TTL of the optical lens and the maximum optical effective diameter Ømax in all lenses satisfy: 1 max < TTL / Ømax

[0019] Optionally, the optical effective diameter Ø of any lens in the optical lens and the center thickness T thereof satisfy: 2

[0020] Optionally, the overall transmittance T of the optical lens satisfies: T≥90%.

[0021] Optionally, the optical lens further comprises a diaphragm located on the imaging side of the first group. The aperture of the diaphragm is 2.4mm-2.8mm, and the axial distance between the diaphragm and the first lens closest to the imaging side in the first group is 0.2mm-0.8mm.

[0022] In a second aspect, an embodiment of the present application provides an optical display device, which comprises the optical lens according to the first aspect.

[0023] The present application has the following beneficial effects: The optical lens provided by the present application adopts an asymmetric glass-plastic hybrid optical architecture composed of a double-cemented glass group, a multi-piece group containing positive and negative lenses, a single positive lens glass group, and a plastic aspheric group, effectively increases the field of view of the optical lens (for example, the field of view can reach at least 60°) without relying on too many lenses or expensive materials, and at the same time, the correction of aberration and the miniaturization of the system are taken into account, thereby improving the imaging quality and user experience as a whole. The optical design provided by the present application overcomes the technical bottleneck in the traditional optical design, and achieves an excellent balance between a large field of view FOV, high-performance image quality, small size, and low cost.

[0024] Other features of the present application and its advantages will become apparent from the following detailed description of exemplary embodiments thereof, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0025] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present specification and, together with the description, serve to explain the principles of the present specification.

[0026] Figure 1 Structure schematic view of optical lens provided by an embodiment of the present application; Figure 2 Structure schematic view of optical lens provided by an embodiment of the present application; Figure 1 Optical path schematic view of optical lens shown in the figure; Figure 3 Point spread diagram of optical lens provided by an embodiment of the present application; Figure 4 Modulation transfer function diagram of optical lens provided by an embodiment of the present application; Figure 5 MTF curve diagram of optical lens provided by an embodiment of the present application under different fields of view; Figure 6 Field curvature and distortion diagram of optical lens provided by an embodiment of the present application; Figure 7 Relative illumination diagram of optical lens provided by an embodiment of the present application; Figure 8 Defocus modulation transfer function diagram of optical lens provided by an embodiment of the present application; Figure 9 Structure schematic view of optical lens provided by an embodiment of the present application; Figure 10 Structure schematic view of optical lens provided by an embodiment of the present application; Figure 9 Optical path schematic view of optical lens shown in the figure; Figure 11 Point spread diagram of optical lens provided by an embodiment of the present application; Figure 12 Modulation transfer function diagram of optical lens provided by an embodiment of the present application; Figure 13 MTF curve diagram of optical lens provided by an embodiment of the present application under different fields of view; Figure 14 Field curvature and distortion diagram of optical lens provided by an embodiment of the present application; Figure 15 Relative illumination diagram of optical lens provided by an embodiment of the present application; Figure 16 Defocus modulation transfer function diagram of optical lens provided by an embodiment of the present application.

[0027] Explanation of reference signs: 100, first group; 101, first lens; 102, second lens; 200, second group; 201, third lens; 202, fourth lens; 300, third group; 301, fifth lens; 400, fourth group; 401, sixth lens; 500, imaging chip group; 01, diaphragm. DETAILED DESCRIPTION

[0028] 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.

[0029] The following description of at least one example embodiment is merely exemplary in nature and is in no way intended to limit the application or its application or uses.

[0030] Techniques and equipment known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered part of the specification where appropriate.

[0031] 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.

[0032] 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.

[0033] The optical lens and optical display device provided by the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0034] According to one embodiment of the present application, an optical lens is provided, referring to Figure 1 and Figure 2 , the optical lens comprises, in order from the imaging side to the image source side along the optical axis, a first group 100, a second group 200, a third group 300, a fourth group 400, and an imaging chip group 500. The first group 100 is a double cemented lens group, comprising two glass spherical lenses, wherein the first lens 101 is a positive lens and the second lens 102 is a negative lens. The second group 200 comprises at least two lenses, including a positive lens and a negative lens. The third group 300 comprises at most one glass spherical lens with positive optical power. The fourth group 400 comprises at least one plastic aspherical lens with negative optical power. The imaging chip group 500 is disposed closest to the image source side.

[0035] The optical lens provided by the embodiments of the present application comprises a plurality of lens groups with specific optical powers and functions and an imaging chip group 500 in sequence along an optical axis. The optical lens provided by the embodiments of the present application adopts an asymmetric glass-plastic hybrid optical architecture, and through the synergistic effect of each group, excellent optical performance is achieved. In other words, the optical architecture provided by the present application aims to efficiently achieve a large field of view and high-level aberration correction through the different roles and synergistic cooperation of each group in the optical path.

[0036] The optical lens provided by the embodiments of the present application comprises a first group 100 located on the image source side of the stop 01. Referring to Figure 1 and Figure 2 , the first group 100 is a double-cemented glass lens group, which comprises a positive lens (i.e. a first lens 101) and a negative lens (i.e. a second lens 102) adjacent to the stop 01 on the optical axis. In the optical path, the imaging light from the imaging chip group 500 enters the first group 100 after passing through the fourth group 400, the third group 300 and the second group 200 in sequence, and finally passes through the stop 01 to exit to the external optical waveguide device to enter the human eye.

[0037] The first group 100, as the last lens group through which the light passes before entering the stop 01, mainly undertakes the function of correcting the axial chromatic aberration of the system, and lays the foundation for the optical lens to achieve a large field of view through the converging effect of the light. Among them, the first lens 101 is a positive lens, which is designed to have a high refractive index characteristic, and the second lens 102 is a negative lens, which is designed to have a low refractive index characteristic. This combination of materials constitutes an effective means of correcting chromatic aberration.

[0038] The optical lens provided by the embodiments of the present application comprises a second group 200, which undertakes the core aberration correction and light path regulation in the optical lens. The second group 200 is designed to comprise at least two lenses, and at least one positive lens and one negative lens, referring to Figure 1 and Figure 2 . Through its specific optical power combination, the second group 200 becomes the key part of correcting the axial aberrations such as field curvature, astigmatism and coma, effectively flattening the image plane, thereby ensuring that high-quality clear imaging can be obtained in the entire field of view from the center to the edge.

[0039] In terms of light path conduction, the second group 200 receives light from the third group 300 and manages the beam aperture and propagation angle in the lens through its reasonable optical power distribution, laying the foundation for efficient light transmission to the subsequent first group 100, and ensuring the smoothness and stability of the entire optical path system.

[0040] In addition, the second group 200 has significant design flexibility. Referring to Figure 1As shown, it can be implemented as a double-cemented lens set; or see Figure 3 As shown, two single-lens structures can be used, which are spaced apart and allow a glass aspheric lens to be introduced therebetween. This flexible configuration provides additional aberration correction freedom for optical design, which is particularly advantageous for targeted correction of high-order aberrations, thereby further optimizing the overall imaging performance of the optical lens without significantly increasing the cost.

[0041] The optical lens provided by the embodiments of the present application includes a third group 300, which plays a key role in converging core light rays and balancing residual aberrations in the optical lens. The third group 300 contains at most one glass spherical lens with positive optical power, as shown in Figure 1 and Figure 3 In the optical path, the light rays from the fourth group 400 enter the third group 300.

[0042] The third group 300, as a key light converging unit in the optical lens, is responsible for effectively converging the light rays from the fourth group, laying the necessary optical path foundation for the light beam to enter the subsequent second group 200 and finally form an image.

[0043] While achieving light convergence, the third group 300 is also used to correct residual aberrations such as spherical aberration in the optical lens. Its optical power and position are optimized to be able to cooperate with the front and rear optical groups, further improving the optical performance, which is specifically manifested in optimizing the spot diagram to reduce the size of the diffraction spot and improving the consistency of the MTF curve.

[0044] In addition, the third group 300 is designed as at most one lens, which is a key consideration for balancing the performance and cost of the optical lens. It effectively controls the total number of lenses and the complexity and production cost of the system while ensuring the necessary converging light and correcting residual aberrations.

[0045] The optical lens provided by the embodiments of the present application includes a fourth group 400, which plays a key role in flattening the image surface and integrating the system. The fourth group 400 contains at least one plastic aspheric lens with negative optical power, as shown in Figure 1 and Figure 2 In the optical path, the light rays from the imaging chip group 500 first enter the fourth group 400.

[0046] The fourth group 400, as the first optical lens group in the light propagation path, is crucial for flattening the image surface with its negative optical power, which can effectively compensate for the field curvature that may be generated by the subsequent positive optical power group. At the same time, the at least one aspheric surface it adopts is the most effective means to correct optical distortion and spherical aberration, ensuring that the projected image has low distortion characteristics and maintains high definition from the center to the edge.

[0047] The fourth group 400 directly determines the back focal length size of the optical lens, i.e. the axial distance between it and the imaging chip group 500, in terms of the volume of the optical lens. Optimization of this distance is the key to miniaturization of the overall structure of the lens and ensures good matching with the display chip. The fourth group 400 acts as the starting control unit of the optical lens, responsible for the preliminary shaping and correction of the light rays emitted by the imaging chip group 500, laying a good foundation for further processing by subsequent groups.

[0048] In addition, the fourth group 400 uses a plastic aspherical lens, which realizes complex surface processing while taking into account the manufacturing cost and lightweighting requirements, reflecting the optimization balance between performance and cost of the optical lens.

[0049] The optical lens provided by the embodiments of the present application includes an imaging chip group 500, which serves as the image source and physical protection unit of the optical lens, located at the starting position of the optical path, as shown in Figure 2 .

[0050] The imaging chip group 500 includes a display chip (such as LCD, DLP or LCOS, etc.), which functions to convert input electrical signals into optical signals carrying image information, constituting the starting point of the entire optical imaging process. In terms of structure, the imaging chip group 500 can also include protective glass, etc. This flat panel optical element does not participate in imaging, but provides critical sealing and dust protection, preventing contaminants from directly contacting the surface of the display chip, thereby ensuring the imaging reliability and stability of the optical lens during long-term use.

[0051] In the complete optical path, the image light generated by the imaging chip group 500 passes through the transmission and correction of the fourth group 400, the third group 300, the second group 200 and the first group 100 in turn, and finally enters the waveguide device through the aperture 01 and reaches the human eye, completing the optical display process.

[0052] Among them, the display chip size is 0.49 inches, and the pixel size is 5.6 microns.

[0053] The optical lens provided by the embodiments of the present application, through the cooperation of the above five groups, constitutes a functional optical system as a whole. Each group plays a specific role in the optical path and forms an effective complement: the imaging chip group 500 serves as the starting point of the system and provides the original image light signal; the fourth group 400 is the key to image plane flattening and integration optimization, and corrects the initial distortion of the light; the third group 300 undertakes the core light convergence function; the second group 200 is the main force for correcting off-axis aberrations, ensuring uniform image quality across the field of view; and the first group 100 mainly corrects chromatic aberration and completes the final aberration balance. Through this innovative asymmetric glass-plastic hybrid architecture, the optical lens provided by the present application integrates multiple core performance advantages. Specifically: Large field of view: The diagonal field of view (FOV) is realized to be 60° or more, far exceeding the about 30° of traditional AR lenses, significantly improving the visual immersion.

[0054] High resolution: The full-field MTF is greater than 0.6 at a high spatial frequency of 89 lp / mm, close to the diffraction limit, ensuring clear reproduction of picture details.

[0055] Compact size: The total length TTL of the optical lens is controlled to be within 13.5 mm, and the optical architecture meets the requirements of compact size and length-diameter ratio, effectively supporting the miniaturization design of AR devices.

[0056] Reasonable cost: The hybrid scheme of mainly using glass spherical lenses and using plastic aspherical lenses at key positions is adopted, which realizes excellent cost control while ensuring high performance.

[0057] In summary, the present application provides an optical solution for AR display devices that achieves an excellent balance between immersion, clarity, volume, and cost through architectural innovation and parameter optimization.

[0058] In summary, the optical lens provided by the embodiments of the present application overcomes the technical bottlenecks in traditional optical design by adopting an asymmetric glass-plastic hybrid architecture composed of a double-cemented glass group, a multi-piece group containing positive and negative lenses, a single positive lens glass group, and a plastic aspherical group. This optical design significantly expands the field of view of the optical lens to more than 60° without relying on excessive lenses or special expensive materials, while achieving a high resolution performance with an MTF value greater than 0.6 at a spatial frequency of 89 lp / mm in the full field of view. Through precise allocation of the focal power of each group and effective use of aspherical technology, the system ensures excellent aberration correction ability while controlling the total optical length to be within 13.5 mm, achieving an excellent balance between large field of view, high imaging quality, compact size, and reasonable cost. The present application provides an optical solution for AR display devices with excellent comprehensive performance.

[0059] In some examples of the present application, referring to Figure 1 The first lens 101 is a double convex lens with a refractive index Nd 101 satisfying 1.80 < Nd 101 < 1.85 and an Abbe number Vd 101 > 40. Please continue to refer to Figure 1 The second lens 102 is a double concave lens with a refractive index Nd 102 < 1.65 and an Abbe number Vd 102 < 34.

[0060] In this example provided by the present application, the first group 100 is designed as a double cemented lens group, and the specific composition and material selection thereof embodies a precise optical design. Specifically: The first lens 101 is designed as a double convex positive lens, and the optical material thereof has the characteristics of high refractive index (such as the refractive index Nd 101 satisfying 1.80 < Nd 101 < 1.85) and high Abbe number (such as the Abbe number Vd 101 > 40). Such material selection enables the first lens 101 to effectively control the influence of chromatic dispersion on the imaging quality while providing the necessary positive focal power.

[0061] The second lens 102 is designed as a double concave negative lens, and the optical material thereof has the characteristics of low refractive index (such as the refractive index Nd 102 < 1.65) and low Abbe number (such as the Abbe number Vd 102 < 34). Such material exhibits relatively high chromatic dispersion characteristics, which is in sharp contrast to the material of the first lens 101.

[0062] In the first group 100, two glass lenses with opposite focal powers and significantly different chromatic dispersion characteristics are combined through a cementing process to form an achromatic cemented group. When light passes through the cemented interface between the two lenses, the significant difference in Abbe number of the two materials can effectively make different wavelengths of chromatic light converge to the same point after passing through the group, thereby achieving excellent chromatic aberration correction effect.

[0063] The specific optical design in this example can bring the following beneficial effects to the optical lens: By adopting the first group 100 composed of high Abbe number and low Abbe number materials, the optical lens effectively corrects the axial chromatic aberration caused by the focal length difference of different wavelengths of light in the final stage of light propagation. This design eliminates the chromatic dispersion phenomenon in imaging, and provides an important guarantee for the optical system to achieve high resolving power of MTF > 0.6 at a spatial frequency of 89 lp / mm.

[0064] The doublet structure not only helps to correct spherical aberration, but also the positive and negative lens power distribution creates conditions for controlling the propagation path of large-angle light rays. This optical architecture enables the optical lens to support a large field of view FOV of more than 60°, while maintaining good illumination uniformity across the image plane.

[0065] As the last mirror group in the light ray propagation path, the first group 100 undertakes the main chromatic aberration correction function, which enables the front mirror groups to focus on the correction of other aberrations. This aberration correction distribution strategy enhances the overall robustness of the optical lens, while reducing the sensitivity to manufacturing tolerances, thereby improving product consistency and production yield.

[0066] Compared with solutions that use special ultra-low dispersion glass or increase the number of lenses, this design scheme based on the optimized combination of the characteristics of conventional glass materials effectively controls the material cost and processing complexity while ensuring excellent optical performance, and is an innovative technical path to achieve a balance between high performance and low cost.

[0067] This optical design enables the light rays emitted from the imaging chip group 500 to pass through each mirror group in turn and finally form a high-quality optical image, meeting the strict requirements of AR display devices for optical performance.

[0068] In some examples of the present application, the focal length f1 of the first lens 101 satisfies: 5.3mm≤f1≤5.7mm; the focal length f2 of the second lens 102 satisfies: -9.0mm≤f2≤-9.6mm.

[0069] This example of the present application optimizes the power of the two lenses in the first group 100.

[0070] The positive focal length (5.3mm≤f1≤5.7mm) of the first lens 101 and the negative focal length (-9.0mm≤f2≤-9.6mm) of the second lens 102 form an optimized power ratio. This specific combination ensures that the first group 100 can accurately control the deflection angle of light rays when completing its optical function as the final correction unit, laying the foundation for good aberration balance of the optical lens.

[0071] Under the power configuration in this example, the first group 100 can effectively handle large-angle light rays from the second group 200, ensuring that these light rays enter the aperture 01 at the appropriate angle. This control is crucial for maintaining the flatness of the image plane and the edge quality of the optical lens at a large field of view (such as FOV≥60°), while ensuring that the light rays can be successfully coupled into the subsequent waveguide device.

[0072] This specific focal length range selection allows the first group 100 to achieve the optimal optical correction effect in a limited space. Precise focal length control not only helps control the total length of the optical lens TTL (e.g., TTL≤13.5mm), but also improves the tolerance of the optical lens to manufacturing tolerances, enhancing the consistency and stability of the product.

[0073] By limiting the focal length to this optimized range, the optical lens can achieve the design requirements without relying on special optical materials or complex lens structures. This design effectively controls the manufacturing cost while ensuring optical performance, providing a feasible technical solution for mass production.

[0074] This focal length design presented in this example ensures that the light emitted from the imaging chip group 500 can ultimately form a high-quality optical image that meets the requirements after undergoing step-by-step regulation by each lens group, meeting the strict requirements of AR display devices for optical performance.

[0075] In some examples of the present application, referring to Figure 1 and Figure 2 , the second group 200 is a double-cemented lens group, which includes a third lens 201 and a fourth lens 202 cemented to each other, and both the third lens 201 and the fourth lens 202 are glass spherical lenses; wherein the third lens 201 is a double-concave negative lens, and the fourth lens 202 is a double-convex positive lens.

[0076] In this example of the present application, referring to Figure 1 and Figure 2 , the second group 200 is specifically implemented as a double-cemented lens group formed by the third lens 201 and the fourth lens 202 cemented to each other, and both are glass spherical lenses. Among them, the third lens 201 is a double-concave negative lens, and the fourth lens 202 is a double-convex positive lens.

[0077] The optical design in this example constitutes a correction unit. The cemented structure can effectively correct chromatic aberration, and the negative-positive focal length combination and spherical surface shape mainly aim to correct field curvature and astigmatism and other axial aberrations, which are the main force to ensure uniform image quality across the entire field of view. In this configuration, the second group 200 assumes an important aberration correction function, so the third group 300 (i.e., the fifth lens 301) is needed to further converge light and balance residual aberrations, and the entire optical lens requires a total of six lenses, as shown in Figure 1 . In the optical path, it receives light from the third group 300, corrects aberrations, and then transmits the light to the first group 100.

[0078] In some examples of the present application, referring to Figure 9 and Figure 10The second group 200 is composed of two single lenses, and at most one of them is a glass aspheric lens. The two single lenses include a third lens 201 and a fourth lens 202, wherein the third lens 201 is a negative lens with a concave surface close to the first group 100, and the fourth lens 202 is a positive lens with a convex surface close to the imaging chip group 500.

[0079] In this example of the present application, referring to Figure 9 and Figure 10 , the second group 200 adopts another implementation, which is composed of two single lenses. The two lenses include a third lens 201 and a fourth lens 202, wherein the third lens 201 is a negative lens with a concave surface close to the first group 100, and the fourth lens 202 is a positive lens with a convex surface close to the imaging chip group 500. The key point is that one of the third lens 201 and the fourth lens 202 is a glass aspheric lens.

[0080] The core advantage of the optical design in this example is the introduction of aspheric technology. Aspheric lenses provide powerful and precise control capabilities for correcting high-order aberrations such as distortion and coma. Due to the addition of aspheric surfaces, the aberration correction capability and design freedom of the second group 200 itself are greatly enhanced, and the optical performance has been fully optimized, so in this embodiment, the original third group 300 can be omitted, thereby reducing the total number of lenses in the entire optical lens to five, achieving further miniaturization and cost control. In the optical path, it directly receives light from the fourth group 400, completes more efficient aberration correction, and then transmits the light to the first group 100.

[0081] Referring to Figure 1 and Figure 9 respectively, two examples of the present application demonstrate different technical paths and design flexibility that the second group 200 takes in achieving the system optical target: Figure 1 The implementation shown in the figure adopts mature spherical cementing technology to build a stable and reliable aberration correction module. Figure 9 The implementation shown in the figure, on the other hand, innovatively introduces aspheric technology, optimizing optical performance while reducing the number of lenses. These two differentiated solutions reflect the design idea of the present application to precisely balance and optimize between optical performance, system size, and manufacturing cost.

[0082] In some examples of the present application, referring to Figure 9 and Figure 10The optical architecture shown, the refractive index Nd of the negative lens in the second group 200 is less than 1.65, and the Abbe number Vd is less than 34; the refractive index Nd of the positive lens in the second group 200 satisfies 1.71 < Nd < 1.85, and the Abbe number Vd is greater than 40.

[0083] In this example of the present application, referring to Figure 9 and Figure 10 The optical architecture shown, the refractive index Nd of the negative lens in the second group 200 is less than 1.65, and the Abbe number Vd is less than 34; the refractive index Nd of the positive lens in the second group 200 satisfies 1.71 < Nd < 1.85, and the Abbe number Vd is greater than 40.

[0084] The material combination design in this example aims to build a chromatic and aberration balance unit inside the second group 200. By using the significant difference between the Abbe numbers of the two materials, the second group 200 can effectively correct the axial chromatic aberration such as magnification chromatic aberration generated by the optical lens during the expansion of the field of view; at the same time, the use of high refractive index positive lens helps to reduce the lens curvature while maintaining the optical power, thereby effectively controlling the spherical aberration and high-order aberration, and providing a key guarantee for the optical lens to maintain high imaging quality after simplifying the number of lenses.

[0085] In some examples of the present application, referring to Figure 9 and Figure 10 The optical architecture shown, the focal length f3 of the negative lens in the second group 200 satisfies -4.5mm ≤ f3 ≤ -5.5mm; the focal length f4 of the positive lens in the second group 200 satisfies 5mm ≤ f4 ≤ 6mm.

[0086] In this example of the present application, referring to Figure 9 and Figure 10 The optical architecture shown, the focal length f3 of the negative lens in the second group 200 satisfies -4.5mm ≤ f3 ≤ -5.5mm; the focal length f4 of the positive lens in the second group 200 satisfies 5mm ≤ f4 ≤ 6mm.

[0087] This focal length ratio is the key to achieve the core optical function of the second group 200. The specific power of the negative lens is mainly responsible for flat image surface and control of field curvature; while the specific power of the positive lens is responsible for light convergence and balancing the total power of the system. The two work together to ensure that the light can be transmitted to the first group 100 in the best state after passing through the second group 200. This design enables the second group 200 to still efficiently undertake the core functions of off-axis aberration correction and light path transfer in the simplified architecture of omitting the third group 300, which is the core design to achieve the balance of high performance, small size and low cost of the optical lens.

[0088] In some examples of the present application, referring to Figure 1 , the third group 300 includes a fifth lens 301 which is a biconvex glass spherical lens with a focal length f5 satisfying 11.0mm≤f5≤11.5mm.

[0089] In this example of the present application, referring to Figure 1 , the third group 300 contains a fifth lens 301 which is designed as a biconvex glass spherical lens with a long positive focal length (11.0mm≤f5≤11.5mm). In the light path, the light from the fourth group 400 enters this fifth lens 301. Its core role is to converge the light and collect the light beam transmitted from the front lens group, i.e. the fourth group 400, to create the best conditions for the light to enter the subsequent second group 200 and perform aberration correction.

[0090] In the third group 300, the fifth lens 301 acts as a positive lens, performing the function of convergence while also undertaking the key task of balancing and correcting the residual aberration of the system. Its specific focal length range and biconvex spherical form, after system optimization, can effectively compensate for part of the astigmatism and field curvature generated by the front lens group (i.e. the fourth group 400), and help to control the spherical aberration, thereby synergistically improving the overall imaging quality of the optical lens, specifically manifested as optimizing the spot diagram and improving the consistency of the MTF curve, referring to Figure 3 and Figure 4 .

[0091] Optimizing the design of the third group 300 to have a glass spherical lens with an optimized focal length is a design trade-off: it provides the necessary optical function and ensures stable optical performance while avoiding the cost increase caused by the use of aspherical surfaces or special materials. This design ensures an excellent balance between optical performance, structural complexity and manufacturing cost of the optical lens.

[0092] In some examples of the present application, referring to Figure 1 and Figure 2 , and Figure 9 andFigure 10 The fourth group 400 includes a sixth lens 401, which is a plastic aspheric lens with at least one aspheric surface, and the focal length f6 of the sixth lens 401 satisfies -9mm≤f6≤-8mm; the minimum air gap between the sixth lens 401 and the imaging chip group 500 is 0.3mm~0.5mm.

[0093] The fourth group 400 includes a sixth lens 401, which is designed as a plastic aspheric lens and has a specific negative focal length (the focal length f6 satisfies -9mm≤f6≤-8mm). In the optical path, the fourth group 400 serves as the first regulating unit of the imaging light beam and directly receives the initial light from the imaging chip group 500. Its negative focal length can be used to balance the total focal length of the optical lens, and also preliminarily corrects the curvature of the image plane, laying a foundation for subsequent aberration control of the optical path.

[0094] The fourth group 400 includes a sixth lens 401, which is designed as a plastic aspheric lens and has a specific negative focal length (the focal length f6 satisfies -9mm≤f6≤-8mm). In the optical path, the fourth group 400 serves as the first regulating unit of the imaging light beam and directly receives the initial light from the imaging chip group 500. Its negative focal length plays a dual role in the optical system: on the one hand, it balances the total focal length of the optical lens, and on the other hand, it compensates for the inherent field curvature of the lens through its specific focal length distribution, making the image plane tend to be flat. This image field correction at the front end lays an important foundation for subsequent aberration control of the lens group.

[0095] The minimum air gap of 0.3mm~0.5mm between the sixth lens 401 and the imaging chip group 500 is an optimized back focal length parameter. This design ensures the physical space of the display chip while greatly compressing the total length TTL of the optical lens (TTL≤13.5mm), achieving the synergy of optical performance and mechanical compactness, and is an important guarantee for the overall miniaturization and high integration of the optical lens.

[0096] The aspheric lens is formed by plastic material, which has flexibility in complex surface type and controllability in cost. This choice fully utilizes the correction ability of aspheric technology while effectively reducing the system manufacturing cost and weight.

[0097] In some examples of the present application, the aspheric surface of the aspheric lens is an even aspheric surface, and the sag of the surface type is defined by the following formula: ; Wherein z is the sag of the surface type, c is the reciprocal of the radius of curvature, k is the conic coefficient, and a1 to a8 are even aspheric coefficients.

[0098] In different examples of the present application, all aspheric lenses (including the plastic aspheric lenses of the fourth group 400 and the glass aspheric lenses possibly existing in the second group 200) adopt even aspheric design. The aspheric surface is defined by a standard even aspheric formula, and the high-order mathematical control of the sag of the lens surface is realized through the conic coefficient k and a plurality of even aspheric coefficients (a1 to a8, see Table 2 of Example 1 and Table 4 of Example 2 for specific values). This coefficient configuration provides sufficient control dimensions for the optical lens, can accurately correct various aberrations, and is a key technical means to achieve excellent imaging quality.

[0099] In specific implementation, the configuration of the aspheric lens has design flexibility: referring to Example 1 shown in Figure 1 and Figure 2 , only one aspheric lens is provided in the fourth group 400 in the optical lens; and referring to Example 2 shown in Figure 9 and Figure 10 , a double-aspheric configuration is adopted in the optical lens, including an aspheric lens (the second lens 202) in the second group 200 and an aspheric lens (the sixth lens 401) in the fourth group 400. This differentiated aspheric configuration strategy embodies the diversified solutions provided by the present application to balance the complexity of the optical lens and the manufacturing cost while meeting the optical performance requirements.

[0100] Referring to Table 3 in Example 1 and Table 6 in Example 2, the conic coefficient and aspheric coefficient of each aspheric surface are systematically optimized and assigned. By accurately configuring these parameters (for example, the conic coefficient k of the tenth surface in Table 2 is -15.956, and the fourth-order coefficient a1 is -1.04E-02), the aspheric lens can accurately correct specific aberrations in a large field angle optical lens, including distortion, spherical aberration, and astigmatism. This precise coefficient optimization enables the system to achieve high resolution (MTF>0.6) while keeping the number of lenses minimized.

[0101] In the complete imaging light path, the light from the imaging chip group 500 first passes through the fourth group 400 with aspheric surfaces. The aspheric surfaces of the fourth group 400 undertake the functions of initial image field flattening and distortion correction; when the second group 200 contains aspheric lenses, they further play a role in correcting astigmatism and coma. This multi-aspheric collaborative design strategy enables the optical lens to achieve a large field angle of 60° while effectively controlling the field curvature and maintaining a high relative luminance, ensuring the uniformity and clarity of the imaging quality in the full field of view.

[0102] In some examples of the present application, the focal length f i of any lens in the optical lens satisfies: 0.56≤|fi |f1 / F|≤1.5; wherein the total focal length F of the optical lens is 7.9mm≤F≤8.1mm.

[0103] In the optical lens design of the present application, the focal length f of each lens i The proportional relationship with the total focal length F of the optical lens is optimized and designed, and the focal length f of any lens i The total focal length F of the optical lens satisfies: 0.85≤|f i |F|≤3, and the total focal length F of the optical lens is controlled within the range of 7.9mm to 8.1mm. This proportional relationship ensures the reasonable distribution of the refractive power of each lens in the system.

[0104] In the first group 100: the ratio of the focal length f1 of the first lens 101 to the total focal length F of the optical lens is 0.65≤|f1 / F|≤0.72; the ratio of the focal length f2 of the second lens 102 to the total focal length F of the optical lens is 1.11≤|f2 / F|≤1.21.

[0105] In the second group 200: the ratio of the focal length f3 of the third lens 201 to the total focal length F of the optical lens is 0.56≤|f3 / F|≤0.70; the ratio of the focal length f4 of the fourth lens 202 to the total focal length F of the optical lens is 0.62≤|f4 / F|≤0.76.

[0106] In the third group 300: the ratio of the focal length f5 of the fifth lens 301 to the total focal length F of the optical lens is 1.36≤|f5 / F|≤1.45; In the fourth group 400: the ratio of the focal length f6 of the sixth lens 401 to the total focal length F of the optical lens is 0.99≤|f6 / F|≤1.14.

[0107] The proportion of the focal length of each lens to the total focal length of the optical lens is optimized and configured to avoid lenses with excessively strong or weak refractive power, thereby ensuring smooth transition of light in the optical lens.

[0108] By limiting the refractive power of each lens within a reasonable range, the optical lens can achieve the best aberration correction effect. Excessively strong refractive power is easy to introduce high-order aberrations, while excessively weak refractive power is difficult to effectively participate in aberration correction. This matching design makes each lens work together to share the task of aberration correction.

[0109] The parameter design in this example effectively controls the total length (TTL≤13.5mm) of the optical lens under the premise of ensuring the optical performance. The precise total focal length F control (F≈8mm) combined with reasonable power distribution enables the optical lens to achieve a large field of view of 60° while maintaining excellent optical performance (MTF>0.6@89lp / mm) and compact structure size.

[0110] This focal ratio scheme reflects the innovation of the present application at the optical architecture level and is one of the key technical features to achieve a high-performance, small-size, and high-yield optical lens.

[0111] In some examples of the present application, the total length TTL of the optical lens is ≤13.5mm.

[0112] The present application controls the total length TTL of the optical lens to be within 13.5mm, which has the beneficial effect of directly contributing to the miniaturization and light weight of the optical lens, which is crucial for wearable devices such as AR glasses with limited space, enabling them to have excellent wearing comfort and product portability while ensuring large field of view and high-resolution imaging performance.

[0113] In some examples of the present application, the total length TTL of the optical lens and the maximum optical effective diameter Ømax of all lenses satisfy: 1 max <2.

[0114] In this example of the present application, the ratio of the total length TTL of the optical lens to the maximum lens effective diameter is controlled to be between 1 and 2, ensuring the coordinated optimization of the size of the optical lens in the radial and axial directions, so that the optical lens maintains balanced optical performance and excellent mechanical stability while achieving a compact structure, providing a more flexible and reliable optical solution for AR optical display devices.

[0115] If the ratio of the total length TTL of the optical lens to the maximum optical effective diameter Ømax is not 1 max <2, the following defects will occur: When TTL / Ø max ≤1, the optical lens is too short and thick. This means that the lens curvature is too steep or the power is too concentrated, which will introduce high-order aberrations that are difficult to correct, while causing a sharp decline in edge field illumination and deterioration of image flatness. In addition, the lens spacing is excessively compressed, which easily causes stray light and significantly increases the assembly difficulty.

[0116] When TTL / Ø max ≥2, the optical lens is too long and thin. Although the difficulty of aberration correction may be reduced, the total optical length is significantly increased, which violates the core requirement of compact volume for AR devices.

[0117] Therefore, controlling the ratio between 1 and 2 is the key to balance the optical performance and compactness of the optical lens.

[0118] In some examples of the present application, the ratio of the optical effective diameter Ø of any lens in the optical lens to the center thickness T thereof satisfies 2 < Ø / T < 6.

[0119] This example of the present application can bring the following effects by limiting the ratio of the optical effective diameter Ø of any lens in the optical lens to the center thickness T thereof to between 2 and 6: Avoiding grinding deformation caused by too thin lens (Ø / T is too large), while preventing optical material waste and weight increase caused by too thick lens (Ø / T is too small); Within this ratio range, the light propagation path in the lens is reasonably controlled, effectively suppressing the spherical aberration, coma and other aberrations introduced by the lens shape factor, providing a basis for the lens to achieve high resolving power of MTF > 0.6; This ratio takes into account the feasibility of molding / grinding process, avoiding yield reduction caused by extreme ratio, improving the production economy while ensuring optical performance.

[0120] As can be seen, this design enables the optical lens to pursue large field of view and miniaturization while taking into account the comprehensive optimization of reliability, performance and cost.

[0121] In some examples of the present application, the overall transmittance of the optical lens is T ≥ 90%.

[0122] The present application improves the overall transmittance of the optical lens to 90% and above, which significantly improves the light energy utilization, not only directly enhances the display brightness and energy efficiency of the AR device, reduces the power consumption, but also effectively avoids the picture contrast and stray light problems caused by light loss, thereby providing users with brighter, more colorful and clearer visual experience.

[0123] In some examples of the present application, referring to Figure 1 and Figure 9 , the optical lens further comprises a diaphragm 01 located on the imaging side of the first group 100; the aperture of the diaphragm 01 is 2.4mm-2.8mm, and the axial distance between the diaphragm 01 and the first lens 101 closest to the imaging side in the first group 100 is 0.2mm-0.8mm.

[0124] The diaphragm 01 is arranged on the imaging side of the first group 100 (the diaphragm 01 is a front diaphragm), and the aperture of the diaphragm 01 is limited to 2.4mm~2.8mm, and the axial distance between the diaphragm 01 and the first lens 101 is controlled to be 0.2mm~0.8mm. This design has multiple benefits: first, the accurate aperture size effectively controls the amount of light and matches the optical lens F number, balancing aberration and lens brightness; second, the position and distance can best define the optical lens aperture diaphragm, effectively suppress axial aberration (such as coma, astigmatism), and ensure the imaging quality of the edge field under a large field angle; third, this compact layout reserves space for the subsequent light path of the diaphragm 01 to the waveguide, which is the key to realizing the compactness and performance optimization of the entire optical system structure.

[0125] The optical lens of the present application is specifically described below through Example 1 and Example 2.

[0126] Example 1 Referring to FIGS. 1 and 2, the optical lens comprises, along the optical axis from the imaging side to the image source side, a first group 100, a second group 200, a third group 300, a fourth group 400, and an imaging chip group 500; wherein the imaging chip group 500 is arranged closest to the image source side. Figure 1 The first group 100 is a double-cemented lens group, comprising two glass spherical lenses, wherein the first lens 101 is a biconvex positive lens, and the second lens 102 is a biconcave negative lens. Figure 2 The second group 200 is a double-cemented lens group, comprising a third lens 201 and a fourth lens 202 cemented with each other, and the third lens 201 and the fourth lens 202 are both glass spherical lenses; wherein the third lens 201 is a biconcave negative lens, and the fourth lens 202 is a biconvex positive lens. The third group 300 comprises a fifth lens 301, and the fifth lens 301 is a biconvex glass spherical lens with positive optical power. The fourth group 400 comprises a sixth lens 401, and the sixth lens 401 is a plastic aspherical lens with negative optical power, and at least one surface of the sixth lens 401 is aspherical.

[0127] In this embodiment 1, by reasonably allocating the optical power of each group and optimizing the lens material, the performance indicators and aberration suppression of the optical lens can be balanced, and the optimized design indicators are shown in Table 1: Table 1: Design parameter table

[0128]

[0129] ​​Please refer to Table 2 below for the optical parameters of the six lenses in this embodiment 1. This embodiment 1 includes an aspherical lens, which is the sixth lens 401 (including the ninth and eleventh surfaces) in the fourth group 400. Please refer to Table 3 for the aspherical coefficient of the sixth lens 401.

[0130] Table 2: Optical Parameter Table

[0131] Table 3: Aspheric Coefficients

[0132] Figure 3 This is a dot array diagram of the optical lens provided in Embodiment 1. Due to aberrations, when light rays converge on the image plane, they are not a single point, but rather a diffuse spot distributed within a certain range. The diameter of this diffuse spot and the concentration of light rays represent the magnitude of the aberration. From... Figure 3 As can be seen, the root mean square radius of the diffuse spot is ≤1.6 micrometers (0.3 pixels), indicating that the aberrations have been well corrected.

[0133] from Figure 4 and Figure 5 The adjusted transfer function plot shows that at a cutoff frequency of 89 lp / mm, the MTF of each field of view is close to the diffraction limit, and the MTF > 0.6, indicating that this optical lens has strong resolution and can reproduce the details of the image very well.

[0134] See Figure 6 The optical distortion of this lens is ≤10%, the field curvature is less than or equal to 0.06mm, and the aberrations are suppressed to a low level. Figure 7 In the relative illumination map, a relative illumination greater than 68% is a high value, which can effectively avoid the phenomenon of uneven brightness distribution (bright center and dark edges) caused by edge light loss. Figure 8 The graph shows the defocus modulation transfer function at room temperature (20℃). Figure 8 As can be seen, Through focus MTF > 0.6, the image quality is high and it can well represent the details of the projected image.

[0135] Example 2 See Figure 9 and Figure 10 As shown, the optical lens includes, along the optical axis from the imaging side to the image source side, the following components in sequence: a first group 100, a second group 200, a fourth group 400, and an imaging chip group 500; wherein, the imaging chip group 500 is located closest to the image source side. The first group 100 is a double glass aspherical lens group, comprising two glass aspherical lenses, wherein the first lens 101 is a double-convex positive lens, and the second lens 102 is a double-concave negative lens. The second group 200 is composed of two single lenses which are spaced apart, and at most one of which is a glass aspherical lens; the two single lenses include a third lens 201 and a fourth lens 202, wherein the third lens 201 is a negative lens, and the surface close to the first group 100 is concave, and the fourth lens 202 is a positive lens, and the surface close to the imaging chip group 500 is convex. The fourth group 400 comprises a sixth lens 401 which is a plastic aspherical lens with negative power, and at least one surface of which is aspherical.

[0136] In this embodiment 2, by reasonably allocating the power of each group and optimizing the material of the lens, the performance index and aberration suppression of the optical lens can be balanced, and the optimized design index is shown in Table 4: Table 4: Design parameter table

[0137] The optical parameters of the five lenses in this embodiment 2 are shown in Table 5 below. This embodiment 2 comprises two aspherical lenses, i.e. the fourth lens 202 (including the seventh surface and the eighth surface) in the second group 200 and the sixth lens 401 (including the ninth surface and the eleventh surface) in the fourth group 400. The aspherical coefficients of the fourth lens 202 and the sixth lens 401 are shown in Table 6.

[0138] Table 5: Optical parameter table

[0139] Table 6: Aspherical coefficients

[0140] Figure 11 The spot array diagram of the optical lens provided in this embodiment 2 shows that, due to the existence of aberration, the light converges on the image plane is not a point, but a diffraction spot distributed within a certain range. The diameter of the diffraction spot and the light concentration degree represent the size of the aberration. From Figure 11 it can be seen that the root mean square radius of the diffraction spot is ≤1.8 microns (0.3 pixels), which indicates that the aberration is well corrected.

[0141] From Figure 12 and Figure 13It can be seen from the adjustment transfer function diagram that the MTF of each field is close to the diffraction limit at the cut-off frequency of 89 lp / mm, and the MTF is greater than 0.6, indicating that the resolving power of the optical lens is strong, and the details of the picture can be well presented.

[0142] Referring to Figure 14 The optical distortion of the optical lens is less than or equal to 10%, the field curvature is less than or equal to 0.06 mm, and the aberration is suppressed at a low level. Figure 15 In the relative luminance diagram, the relative luminance is greater than 68%, which is at a high value, and can effectively avoid the phenomenon of uneven brightness distribution of the picture (bright in the middle and dark in the four corners) caused by loss of edge light. Figure 16 The defocus modulation transfer function diagram is at room temperature (20℃), and it can be seen from Figure 16 that the Though focus MTF is greater than 0.6, the imaging quality is high, and the details of the projection picture can be well presented.

[0143] According to another embodiment of the application, an optical display device is provided, which includes the optical lens as described above.

[0144] The optical lens can be used to project image light to the coupling-in region of the optical waveguide device, and through the conduction and beam expansion effect of the optical waveguide device, the enlarged virtual image is finally transmitted to the human eye.

[0145] The optical display device provided in the embodiments of the application is, for example, an AR optical device, such as AR smart glasses.

[0146] The specific implementation of the optical display device of the embodiments of the application can refer to the above-mentioned embodiments of the optical lens, and therefore at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described here.

[0147] In the above embodiments, the differences between the embodiments are mainly described, and the different optimization features between the embodiments can be combined to form a better embodiment as long as they are not contradictory. Considering the brevity of the writing, it will not be described here.

[0148] Although some specific embodiments of the application have been described in detail by examples, those skilled in the art should understand that the above examples are only for illustration, but not for limiting the scope of the application. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the application. The scope of the application is defined by the appended claims.

Claims

1. An optical lens characterized in that, In order from the imaging side to the image source side along the optical axis, the optical lens comprises: a first group (100), which is a double-cemented lens group and comprises two glass spherical lenses, wherein a first lens (101) is a positive lens and a second lens (102) is a negative lens; a second group (200), which comprises at least two lenses and comprises a positive lens and a negative lens; a third group (300), which comprises at most one glass spherical lens with positive optical power; a fourth group (400), which comprises at least one plastic aspherical lens with negative optical power; and an imaging chip group (500) arranged closest to the image source side.

2. The optical lens of claim 1, wherein, The first lens (101) is a biconvex lens, with a refractive index Nd 101 satisfying 1.80 < Nd 101 < 1.85, and an Abbe number Vd 101 > 40; The second lens (102) is a biconcave lens with a refractive index Nd 102 < 1.65, Abbe number Vd 102 < 34.

3. The optical lens according to claim 1 or 2, characterized in that, The focal length f1 of the first lens (101) satisfies 5.3 mm≤f1≤5.7 mm. The focal length f2 of the second lens (102) satisfies -9.0 mm≤f2≤-9.6 mm.

4. The optical lens of claim 1, wherein, The second group (200) is a double-cemented lens group comprising a third lens (201) and a fourth lens (202) cemented to each other, and the third lens (201) and the fourth lens (202) are both glass spherical lenses; wherein the third lens (201) is a double-concave negative lens, and the fourth lens (202) is a double-convex positive lens.

5. The optical lens of claim 1, wherein, The second group (200) is composed of two single lenses arranged at intervals, and at most one of the two single lenses is a glass aspherical lens. The two single lenses comprise a third lens (201) and a fourth lens (202), wherein: The third lens (201) is a negative lens, and the surface close to the first group (100) is a concave surface. The fourth lens (202) is a positive lens, and the surface close to the imaging chip group (500) is a convex surface.

6. The optical lens of claim 1, 4 or 5, wherein, The refractive index Nd of the negative lens in the second group (200) is less than 1.65, and the Abbe number Vd is less than 34. The refractive index Nd of the positive lens in the second group (200) satisfies 1.71<Nd<1.85, and the Abbe number Vd is greater than 40.

7. The optical lens of claim 6, wherein, The focal length f3 of the negative lens in the second group (200) satisfies -4.5 mm≤f3≤-5.5 mm. The focal length f4 of the positive lens in the second group (200) satisfies 5 mm≤f4≤6 mm.

8. The optical lens of claim 4, wherein, The third group (300) comprises a fifth lens (301), which is a double-convex glass spherical lens, and the focal length f5 of the fifth lens (301) satisfies 11.0 mm≤f5≤11.5 mm.

9. The optical lens of claim 1, wherein, The fourth group (400) comprises a sixth lens (401), which is a plastic aspherical lens, at least one surface of the sixth lens (401) is an aspherical surface, and the focal length f6 of the sixth lens (401) satisfies -9 mm≤f6≤-8 mm. The minimum air gap between the sixth lens (401) and the imaging chip group (500) is 0.3 mm-0.5 mm.

10. The optical lens according to claim 5 or 9, characterized in that, The aspherical surface of the aspherical lens is an even aspherical surface, and the sag of the aspherical surface is defined by the following formula: ； wherein z is the sag, c is the reciprocal of the radius of curvature, k is the conic coefficient, and α1-α8 are even aspherical coefficients.

11. The optical lens of claim 1, wherein, a focal length f of any lens in the optical lens i satisfies: 0.56≤|f i / F|≤1.5; wherein the total focal length F of the optical lens satisfies: 7.9mm≤F≤8.1mm.

12. The optical lens of claim 1, wherein, The total length TTL of the optical lens is less than or equal to 13.5 mm.

13. The optical lens of claim 12, wherein, The total track length TTL of the optical lens and the maximum effective optical diameter Ømax in all lenses satisfy: 1 < TTL / Ømax < 2 max <2.

14. The optical lens of claim 1, wherein, An optical effective diameter Ø of any lens in the optical lens and a center thickness T thereof satisfy: 2 < Ø / T < 6.

15. The optical lens of claim 1, wherein, An overall transmittance T of the optical lens is ≥ 90%.

16. The optical lens of claim 1, wherein, The optical lens further comprises a diaphragm (01) located on an imaging side of the first group (100). An aperture of the diaphragm (01) is 2.4 mm ~ 2.8 mm, and an axial distance between the diaphragm (01) and a first lens (101) closest to the imaging side in the first group (100) is 0.2 mm ~ 0.8 mm.

17. An optical display device, characterized by The optical lens according to any one of claims 1-16. The optical lens according to any one of claims 1-16.

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