CN116107065B

CN116107065B - Optical lens and near-eye display system

Info

Publication number: CN116107065B
Application number: CN202310400886.8A
Authority: CN
Inventors: 于笑枝; 闻振宇; 曾昊杰
Original assignee: Jiangxi Lianhao Photoelectric Co ltd
Current assignee: Jiangxi Lianhao Photoelectric Co ltd
Priority date: 2023-04-14
Filing date: 2023-04-14
Publication date: 2023-08-11
Anticipated expiration: 2043-04-14
Also published as: CN116107065A

Abstract

The application discloses an optical lens and a near-eye display system, wherein the optical lens is sequentially provided with the following components along an optical axis from the opposite direction of optical signal transmission: a diaphragm, a first lens, a second lens, a third lens and a prism; the first lens has positive focal power, the light emergent surface is a convex surface, and the light incident surface is a convex surface at a paraxial region; the second lens has negative focal power, the light emergent surface is concave at a paraxial region, and the light incident surface is convex at the paraxial region; the light emergent surface of the third lens is a concave surface and the light incident surface is a convex surface. The optical lens satisfies the following conditional expression: 1< TTL/f <1.4, wherein TTL represents the total optical length of the optical lens, and f represents the focal length of the optical lens. The optical lens provided by the application has the advantages that the miniaturization, large aperture and high image quality balance of the lens are better realized by reasonably matching the shape and focal power of three lenses with specific refractive power.

Description

Optical lens and near-eye display system

Technical Field

The present application relates to the field of imaging lenses, and in particular, to an optical lens and a near-to-eye display system.

Background

Near-Eye Display (NED) refers to that image light emitted by a miniature image light source is guided to a pupil of a user through an eyepiece system by an optical technology, a Virtual and enlarged image is realized in a Near-Eye range of the user, visual image, video or text information is provided for the user, and currently, near-Eye Display technology in the market is generally widely applied to a Virtual Reality (VR) system, an augmented Reality (Augmented Reality, AR) system, a Mixed Reality (MR) system and the like, and related Near-Eye Display devices such as a head-mounted Display, AR glasses and VR helmets are more favored by people along with the increasing demands of the user for interactivity and immersiveness of information such as Virtual images and text. Meanwhile, the AR wearing equipment is required to have a small-sized and light-weighted optical engine, and the technical level requirements of the projection optical lens products on imaging quality, optical distortion, light quantity, volume and the like are also increasingly improved.

The projection lens of the optical engine of the AR wearing equipment popular in the market at present has large volume and insufficient luminous flux, so that a clearer picture is difficult to obtain in a darker environment, and the actual requirement cannot be met well; and the number of the lenses of many projection lenses is large, and even the lenses made of all-glass materials are adopted, so that the cost and the volume of the lenses are high, and the projection lenses are not beneficial to popularization and application in the market.

Disclosure of Invention

Therefore, an object of the present application is to provide an optical lens and a near-eye display system for solving the above problems.

The embodiment of the application realizes the aim through the following technical scheme.

In one aspect, the present application provides an optical lens for modulating an optical signal emitted from an image source; the optical lens is sequentially provided with: a diaphragm, a first lens, a second lens, a third lens and a prism; the first lens, the second lens and the third lens respectively comprise a light incident surface and a light emergent surface, and the light incident surface and the light emergent surface are oppositely arranged on the surface of each lens; the first lens has positive focal power, the light emergent surface of the first lens is a convex surface, and the light incident surface of the first lens is a convex surface at a paraxial region; the second lens has negative focal power, the light emergent surface of the second lens is concave at a paraxial region, and the light incident surface of the second lens is convex at the paraxial region; the light emergent surface of the third lens is a concave surface, and the light incident surface of the third lens is a convex surface; the optical lens satisfies the following conditional expression: 1< TTL/f <1.4, wherein TTL represents the total optical length of the optical lens, and f represents the focal length of the optical lens.

In another aspect, the present application also provides a near-eye display system, including: an image source, an optical lens as described above, an optical waveguide; wherein the image source is configured to emit an optical signal, the optical signal including image information; the optical lens is arranged in the light emitting direction of the image source, and the third lens is arranged closer to the image source than the first lens, and is used for modulating the light signals emitted by the image source; the optical waveguide piece is arranged on one side of the optical lens, which is away from the image source, and is used for transmitting the optical signals modulated by the optical lens.

Compared with the prior art, the optical lens provided by the application has the advantages that the lens has smaller optical distortion and larger light flux by reasonably matching the shape and the focal power of three lenses with specific refractive power, so that the brightness of the lens is improved; meanwhile, the light signal image modulation device has the advantages of compact structure, shorter total length, better imaging quality and smaller chromatic aberration under different wavelengths of RGB (three optical primary colors), and better realization of miniaturization, large aperture and high-image-quality balance of the lens, so that the light signal image modulated by the optical lens is bright and clear, better in effect and better in accordance with the development trend of near-eye display equipment.

Drawings

The foregoing and/or additional aspects and advantages of the application will become apparent and may be readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

fig. 1 is a schematic structural diagram of an optical lens according to a first embodiment of the present application.

Fig. 2 is an astigmatic chart of an optical lens according to a first embodiment of the present application.

Fig. 3 is a graph of f-tan (θ) distortion of an optical lens in a first embodiment of the present application.

Fig. 4 is a graph showing a vertical axis chromatic aberration of an optical lens according to a first embodiment of the present application.

Fig. 5 is a schematic structural diagram of an optical lens according to a second embodiment of the present application.

Fig. 6 is an astigmatic chart of an optical lens according to a second embodiment of the present application.

Fig. 7 is a graph of f-tan (θ) distortion of an optical lens in a second embodiment of the present application.

Fig. 8 is a vertical axis chromatic aberration diagram of an optical lens according to a second embodiment of the present application.

Fig. 9 is a schematic structural diagram of an optical lens according to a third embodiment of the present application.

Fig. 10 is an astigmatic chart of an optical lens according to a third embodiment of the present application.

Fig. 11 is a graph of f-tan (θ) distortion of an optical lens in a third embodiment of the present application.

Fig. 12 is a vertical axis chromatic aberration diagram of an optical lens according to a third embodiment of the present application.

Fig. 13 is a schematic structural diagram of a near-eye display system according to a fourth embodiment of the application.

Detailed Description

In order that the objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Several embodiments of the application are presented in the figures. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Like reference numerals refer to like elements throughout the specification.

In this context, near the optical axis means the area near the optical axis. If the lens surface is convex and the convex position is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region.

The application provides an optical lens which can be used for an near-to-eye display system, such as an intelligent AR wearing device such as a head-mounted display, AR glasses and a VR helmet, and can modulate an optical signal emitted from an image source.

The optical lens is provided with, in order along an optical axis from an opposite direction (entrance pupil side to image source side) of optical signal transmission: a diaphragm, a first lens, a second lens, a third lens and a prism; the first lens, the second lens and the third lens respectively comprise a light incident surface and a light emergent surface, and the light incident surface and the light emergent surface are oppositely arranged on the surface of each lens.

The first lens has positive focal power, the light emergent surface is a convex surface, and the light incident surface is a convex surface at a paraxial region; the first lens adopts biconvex plane type setting, is favorable to the incidence of wide-angle light, reduces the head size of camera lens when realizing wide-angle imaging scope.

The second lens has negative focal power, the light emergent surface is concave at a paraxial region, and the light incident surface is convex at the paraxial region; the second lens adopts a concave-convex surface design, which is beneficial to enabling light to enter the system more gradually and correcting aberration generated by the first lens due to light with a large angle of view.

The third lens has positive focal power or negative focal power, the light emergent surface is a concave surface, and the light incident surface is a convex surface; the third lens adopts a concave-convex design, so that aberration brought by the front lens can be better corrected, incident light rays at the edge can be effectively converged, and the overall imaging quality is improved.

The prism is positioned between the third lens and the image source, and can effectively adjust the light rays emitted by the image source so as to realize the combination of different colors and then enter the optical lens, and the light rays enter human eyes after being modulated by the optical lens, so that color image information is presented.

As one embodiment, the optical lens satisfies the following conditional expression: 1< TTL/f <1.4, wherein TTL represents the total optical length of the optical lens, and f represents the focal length of the optical lens. The above conditions are satisfied, and the optical lens can have a short optical total length by reasonably controlling the focal length and the total length of the optical lens, thereby realizing miniaturization of the lens volume.

The optical lens provided by the application has the advantages that three lenses with specific shapes and optical power are reasonably matched, so that the lens has larger aperture, smaller size, lighter weight, smaller chromatic aberration and smaller optical distortion, the large aperture, miniaturization and high-image-quality balance of the lens are better realized, and the development directions of miniaturization, light weight and high-image-quality of near-eye display equipment are well met.

As an embodiment, the third lens may have negative optical power, and the optical lens satisfies the conditional expression: -10< f3/f < -2, wherein f3 represents the focal length of the third lens. The third lens has proper negative focal power, so that the vertical axis chromatic aberration of the system can be better corrected, the chromatic aberration of the marginal view field under different wavelengths of RGB (red, green and blue) is reduced, and the resolving power of the lens in the full view field is improved.

As one embodiment, the optical lens satisfies the following conditional expression: IH/f <0.24, wherein IH represents the actual half-image height of the optical lens. The lens has long focal length and can be matched with a larger image surface, so that an image source with higher pixels can be matched, high-definition imaging is realized, and the lens can obtain the same high-definition imaging effect as that of short-distance shooting when in long-range shooting.

As one embodiment, the optical lens satisfies the following conditional expression: 5< TTL/IH <7, wherein IH represents the actual half-image height of the optical lens. Under the premise of ensuring the imaging quality of the lens, the total length of the lens is reduced to the greatest extent, and miniaturization and large-image-plane balance of the lens are realized, so that the lens has a small volume and simultaneously can have a large enough imaging plane to match with an image source with high pixels, and further more details can be displayed.

As one embodiment, the optical lens satisfies the following conditional expression: f/EPD <2.0, wherein EPD represents an entrance pupil diameter of the optical lens. The range is satisfied, the aperture of the optical lens is favorably enlarged, the large aperture characteristic of the lens is realized, the realization of the large aperture characteristic is favorable for improving the problem that the relative brightness of the edge view field is fast reduced, thereby being favorable for acquiring more scene information and improving the imaging definition of the lens in a bright and dark environment.

As one embodiment, the optical lens satisfies the following conditional expression: -1.3< f1/f2< -0.1, wherein f1 represents the focal length of the first lens and f2 represents the focal length of the second lens. The focal length ratio of the first lens and the second lens can be reasonably controlled by meeting the conditions, the optical lens is favorable for being compatible with RGB wavelength bands to enable the optical lens to have smaller aberration, and the resolving power of the lens in the full view field is improved.

As one embodiment, the optical lens satisfies the following conditional expression: 0.5< DM1/f1<1, wherein DM1 represents the maximum effective aperture of the first lens and f1 represents the focal length of the first lens. The lens has smaller caliber and better realizes miniaturization of the lens volume by reasonably setting the effective caliber and focal length ratio of the first lens.

As one embodiment, the optical lens satisfies the following conditional expression: 0.5< BFL/TTL <0.6, wherein BFL represents the back focal length of the optical lens. The lens has longer optical back focus, so that the three lenses have enough space during assembly, collision between adjacent lenses is avoided, the assembly difficulty is reduced, and the production yield is improved; meanwhile, the lens can have enough back focal length, so that the placement of the prism and the turning of light are facilitated, and the overall imaging quality is improved.

As one embodiment, the optical lens satisfies the following conditional expression: 2< CT1/CT12<3,1< CT2/CT23<2, wherein CT1 represents a center thickness of the first lens, CT2 represents a center thickness of the second lens, CT12 represents an air space on an optical axis of the first lens and the second lens, and CT23 represents an air space on an optical axis of the second lens and the third lens. The light distribution can be effectively regulated by reasonably controlling the thickness of each lens and the air interval ratio between adjacent lenses, so that the sensitivity of the optical lens is reduced, and meanwhile, the structure of the lens is more compact.

As one embodiment, the optical lens satisfies the following conditional expression: 0.2< f1/f <0.6, -3< R1/R2< -0.3, wherein f1 represents a focal length of the first lens, R1 represents a radius of curvature of a light-emitting surface of the first lens, and R2 represents a radius of curvature of a light-entering surface of the first lens. The lens has the advantages that the surface type and the focal length of the first lens can be reasonably controlled, the tortuosity of light can be effectively slowed down, the optical distortion of the optical lens can be corrected, the caliber of the subsequent lens and the volume of the optical lens can be reduced, and the miniaturization of the lens can be realized.

As one embodiment, the optical lens satisfies the following conditional expression: 0.1< R3/R4<1, wherein R3 represents a radius of curvature of the light exit surface of the second lens, and R4 represents a radius of curvature of the light entrance surface of the second lens. The surface type of the second lens can be reasonably controlled, the incident angle of light entering the second lens can be reasonably controlled, the field curvature can be corrected, the resolution quality of the optical lens can be improved, the total optical length can be shortened, and the miniaturization of the system volume can be realized.

As one embodiment, the optical lens satisfies the following conditional expression: 3< |f3/f2| <8, wherein f2 represents a focal length of the second lens and f3 represents a focal length of the third lens. The above conditions are met, and the focal length ratio of the second lens and the third lens is reasonably controlled, so that the lens has good imaging quality under different RGB wavelengths, chromatic aberration of the RGB wavelengths is corrected, and the resolving power of the lens in the full view field is improved.

As one embodiment, the optical lens satisfies the following conditional expression: 0.79< R1/f1<1.5, wherein f1 represents a focal length of the first lens, and R1 represents a radius of curvature of a light-emitting surface of the first lens. The light-emitting surface of the first lens can be reasonably controlled to meet the conditions, the light-passing quantity of the optical lens can be increased, the large aperture characteristic of the lens is realized, and the imaging quality of the lens is effectively improved.

As one embodiment, the optical lens satisfies the following conditional expression: -5< (R1-R2)/(r3+r4) < -0.5, wherein R1 represents a radius of curvature of the light-exiting surface of the first lens, R2 represents a radius of curvature of the light-entering surface of the first lens, R3 represents a radius of curvature of the light-exiting surface of the second lens, and R4 represents a radius of curvature of the light-entering surface of the second lens. The surface types of the first lens and the second lens can be reasonably controlled to be beneficial to improving the resolution quality of a paraxial view field, and meanwhile, the tortuosity of light rays can be reduced to be beneficial to correcting optical distortion and improving the resolution quality of the optical lens.

As an embodiment, the first lens, the second lens and the third lens may be spherical lenses or aspherical lenses, respectively. The aspherical lenses are adopted, so that the number of lenses can be effectively reduced, aberration can be corrected, and better optical performance can be provided.

As an embodiment, when the lens in the optical lens is an aspherical lens, each aspherical surface type may satisfy the following equation:

，

where z is the distance sagittal height from the aspherical surface vertex when the aspherical surface is at a position of height h in the optical axis direction, c is the paraxial curvature of the surface, k is the quadric coefficient conic, A _2i The aspherical surface profile coefficient of the 2 i-th order.

The application is further illustrated in the following examples. In each of the following embodiments, the thickness and radius of curvature of each lens in the optical lens are different, and specific differences can be seen from the parameter table in each embodiment.

First embodiment

Referring to fig. 1, a schematic structural diagram of an optical lens 100 according to a first embodiment of the present application is shown, where the optical lens 100 sequentially includes, along an optical axis, from an opposite direction of optical signal transmission (i.e. from an entrance pupil side of a human eye to an image source surface): a diaphragm ST, a first lens L1, a second lens L2, a third lens L3, and a prism L4; the first lens L1, the second lens L2 and the third lens L3 are plastic aspherical lenses.

The first lens L1 has positive optical power, the light-emitting surface S1 of the first lens is convex, and the light-entering surface S2 of the first lens is convex at a paraxial region.

The second lens L2 has negative focal power, the light-emitting surface S3 of the second lens is concave at a paraxial region, and the light-entering surface S4 of the second lens is convex at a paraxial region.

The third lens L3 has negative focal power, the light-emitting surface S5 of the third lens is concave, and the light-entering surface S6 of the third lens is convex.

The light exit surface S7 and the light entrance surface S8 of the prism L4. The image source is a Micro LED monochromatic light emitting display screen, the light emitting surface is S9, the prism L4 is formed by combining four triangular prisms, the surfaces corresponding to the red light emitting display unit R, the green light emitting display unit G and the blue light emitting display unit B are the light incident surface S8 of the prism, the light is emitted from the light emitting surface S7, and the specific light incidence process is as follows: the red light-emitting display unit R, the green light-emitting display unit G and the blue light-emitting display unit B respectively project light rays onto the prism L4, then the four-gluing prism L4 mixes the light rays with three colors projected by the R, G, B into colors, and then the colored light rays sequentially pass through the third lens L3, the second lens L2 and the first lens L1, enter the optical waveguide (not shown in the figure) and are projected on human eyes through transmission, so that a clear color picture is presented.

Referring to table 1, the parameters of each lens in the optical lens 100 according to the first embodiment of the present application are shown.

TABLE 1

Referring to table 2, the surface coefficients of each aspheric surface of the optical lens 100 according to the first embodiment of the present application are shown.

TABLE 2

Referring to fig. 2, 3 and 4, an astigmatism curve, an optical distortion curve and a vertical chromatic aberration curve of the optical lens 100 according to the first embodiment are shown.

The astigmatism curves in fig. 2 show the degree of curvature of the meridional image plane and the sagittal image plane, and the horizontal axis in the figure shows the amount of shift (in mm) and the vertical axis shows the angle of view (in degrees). As can be seen from fig. 2, the astigmatism of the meridional image plane (broken line in the figure) and the sagittal image plane (solid line in the figure) is controlled within ±0.05 mm, indicating that the astigmatism correction of the optical lens 100 is good.

The distortion curve of fig. 3 shows distortion at different image heights on the imaging plane, in which the horizontal axis shows the f-tan (θ) distortion value and the vertical axis shows the angle of view (in degrees). As can be seen from fig. 3, the optical distortion at different image heights on the imaging plane is controlled within ±1.5%, which means that the distortion of the optical lens 100 is well corrected.

The vertical axis color difference curve of fig. 4 shows the color difference at different image heights on the imaging plane for each center wavelength of RGB with respect to the G center wavelength (0.525 um), and the horizontal axis in fig. 4 shows the vertical axis difference (in microns) for each wavelength with respect to the G center wavelength, and the vertical axis shows the normalized field angle. As can be seen from fig. 4, the vertical chromatic aberration of each center wavelength of RGB with respect to the center wavelength of G is controlled within ±0.4 microns, which indicates that the optical lens 100 can effectively correct the aberration of the fringe field of view and the secondary spectrum of the entire image plane.

Second embodiment

As shown in fig. 5, a schematic structural diagram of an optical lens 200 according to a second embodiment of the present application is provided, the structure of the optical lens 200 in this embodiment is substantially the same as that of the optical lens 100 in the first embodiment, and the difference is that the third lens L3 has negative focal power, the curvature radius, aspheric coefficients, thickness and material of each lens are different, and the image source is a self-luminous full-color display screen, and the prism L4 can be replaced by a flat glass.

Referring to table 3, the parameters of each lens in the optical lens 200 according to the second embodiment of the application are shown.

TABLE 3 Table 3

Referring to table 4, the surface coefficients of each aspheric surface of the optical lens 200 according to the second embodiment of the present application are shown.

TABLE 4 Table 4

Fig. 6, fig. 7 and fig. 8 show an astigmatism curve, an optical distortion curve and a vertical chromatic aberration curve of the optical lens 200 according to the second embodiment.

The astigmatism curves of fig. 6 represent the extent of curvature of the meridional and sagittal image surfaces. As can be seen from fig. 6, the astigmatism of the meridional image plane and the sagittal image plane is controlled within ±0.2 millimeters, indicating that the astigmatism correction of the optical lens 200 is good.

Fig. 7 shows distortion curves for different image heights on the imaging plane. As can be seen from fig. 7, the optical distortion at different image heights on the imaging plane is controlled within ±2%, which means that the distortion of the optical lens 200 is well corrected.

The vertical axis color difference curve of fig. 8 shows the color difference of each center wavelength of RGB at different image heights on the imaging plane with respect to the G center wavelength (0.525 um). As can be seen from fig. 8, the vertical chromatic aberration of each center wavelength of RGB with respect to the center wavelength of G is controlled within ±0.9 microns, which indicates that the optical lens 200 can effectively correct the aberration of the fringe field of view and the secondary spectrum of the entire image plane.

Third embodiment

As shown in fig. 9, a schematic structural diagram of an optical lens 300 according to a third embodiment of the present application is provided, and the structure of the optical lens 300 in this embodiment is substantially the same as that of the optical lens 100 in the first embodiment, and the difference is mainly that the curvature radius, the aspheric coefficients, the thickness and the materials of the lenses are different, and the image source is a self-luminous full-color display screen, and the prism L4 can be replaced by a flat glass.

Referring to table 5, the parameters of each lens in the optical lens according to the third embodiment of the application are shown.

TABLE 5

Referring to table 6, the surface coefficients of each aspheric surface of the optical lens 300 according to the third embodiment of the present application are shown.

TABLE 6

Referring to fig. 10, 11 and 12, an astigmatism curve, an optical distortion curve and a vertical chromatic aberration curve of the optical lens 300 according to the third embodiment are shown.

The astigmatism curves of fig. 10 represent the extent of curvature of the meridional image plane and the sagittal image plane. As can be seen from fig. 10, the astigmatism of the meridional image plane and the sagittal image plane are controlled within ±0.05 mm, indicating that the astigmatism correction of the optical lens 300 is good.

Fig. 11 shows distortion curves for different image heights on the imaging plane. As can be seen from fig. 11, the optical distortion at different image heights on the imaging plane is controlled within ±1.5%, which means that the distortion of the optical lens 300 is well corrected.

The vertical axis color difference curve of fig. 12 shows the color difference of each center wavelength of RGB at different image heights on the imaging plane with respect to the G center wavelength (0.525 um). As can be seen from fig. 12, the vertical chromatic aberration of each center wavelength of RGB with respect to the center wavelength of G is controlled within ±0.5 microns, which indicates that the optical lens 300 can effectively correct the aberration of the fringe field of view and the secondary spectrum of the entire image plane.

Referring to table 7, the optical characteristics of the optical lens provided by the above three embodiments are shown, and the optical characteristics mainly include the focal length F, f#, the total optical length TTL, the field angle FOV, the actual half image height IH of the optical lens, and the related values corresponding to each of the above conditional expressions.

TABLE 7

In summary, the optical lens provided by the application has the following advantages:

(1) Three lens structures with specific refractive power are adopted, the total length of the lens is effectively shortened, the volume of the lens is reduced, high-definition imaging can be realized by matching with an image source (such as a display screen) with 0.13 inch, and miniaturization of the system volume and weight reduction of the quality are better realized.

(2) Through the reasonable collocation of the specific surface shape and the focal power of each lens, the optical lens has larger light flux, and effectively corrects optical distortion, so that the lens has smaller chromatic aberration in different wavelengths of RGB, thereby meeting the requirements of large field angle and high-definition imaging in different wavelengths of RGB.

Fourth embodiment

Referring to fig. 13, a near-eye display system 400 according to an embodiment of the application includes an image source 410, an optical lens (e.g., optical lens 100) according to any of the above embodiments of the application, and an optical waveguide 430. In the near-eye display system 400, light is emitted from the image source 410 side, modulated by an optical lens, and transmitted by the optical waveguide 430 into the entrance pupil side of the human eye.

The image source 410 is configured to emit an optical signal, which includes image information. Specifically, the image source 410 may be one of Micro LED, OLED, LCD, LCOS, M-OLED, etc., and more specifically, in this embodiment, the image source 410 may use a Micro LED display screen of 0.13 inches, which can provide high-definition image information for the optical lens.

The optical lens 100 is disposed in the light emitting direction of the image source 410, and the third lens L3 in the optical lens 100 is disposed closer to the image source 410 than the first lens L1, and the optical lens 100 is configured to modulate the light signal emitted from the image source 410.

The prism L4 is located between the third lens L3 and the image source 410, and the prism L4 can effectively adjust the light emitted by the image source 410 to realize that the light enters the optical lens after being combined with different colors, and the light enters the human eye after being modulated by the optical lens, so as to present color image information.

As an embodiment, as shown in fig. 13, the image source side 410 may be a Micro LED monochromatic light emitting display screen, such as red (R), green (G), and blue (B) light emitting sources, and the prism L4 is a four-glued light splitting prism, which is a combination of four triangular prisms, and can mix RGB three colors into color. The specific light incidence process in the near-eye display system 400 is as follows: the red light-emitting display unit R, the green light-emitting display unit G and the blue light-emitting display unit B respectively project light rays onto the prism L4, then the four-gluing prism L4 mixes the light rays with three colors projected by the R, G, B into colors, and then the colored light rays sequentially pass through the third lens L3, the second lens L2 and the first lens L1, enter the optical waveguide 430 and are projected and imaged on human eyes through transmission, so that a clear color picture is presented.

As an implementation manner, the image source side 410 may also be an LCOS display screen, and since an external auxiliary light source is generally required for LCOS, the prism L4 is a two-glued beam-splitting prism, which is formed by combining two triangular right-angle prisms, and is matched with the auxiliary light source, so as to achieve full-color display.

As an embodiment, the image source side 410 may also be a self-luminous full-color display screen, such as an OLED, where a prism is not required and a flat glass may be used instead.

The optical waveguide 430 is disposed on a side of the optical lens 100 facing away from the image source 410, and is configured to transmit an optical signal modulated by the optical lens 100. The optical waveguide member 430 may be one of a geometric optical waveguide, a diffractive optical waveguide, and the like, but is not limited thereto.

The near-eye display system 400 may be near-eye display devices such as AR glasses, AR helmets, and head-mounted display devices, and the optical lens has the characteristics of small volume, large aperture, and high image quality, and has a compact structure, a shorter total length, good imaging quality and small chromatic aberration at different wavelengths of RGB (three primary colors), and bright and clear optical signal images modulated by the optical lens, better effect, and clearer picture projected to human eyes, so that the near-eye display system with the optical lens has at least the characteristics of small volume, large aperture, and high image quality, and can effectively improve the wearing experience of users.

The foregoing examples illustrate only a few embodiments of the application and are described in detail herein without thereby limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.

Claims

1. An optical lens, characterized in that, along an optical axis, from a direction opposite to optical signal transmission, there are sequentially: a diaphragm, a first lens, a second lens, a third lens and a prism; the first lens, the second lens and the third lens respectively comprise a light incident surface and a light emergent surface, and the light incident surface and the light emergent surface are oppositely arranged on the surface of each lens;

the first lens has positive focal power, the light emergent surface of the first lens is a convex surface, and the light incident surface of the first lens is a convex surface at a paraxial region;

the second lens has negative focal power, the light emergent surface of the second lens is concave at a paraxial region, and the light incident surface of the second lens is convex at the paraxial region;

the light emergent surface of the third lens is a concave surface, and the light incident surface of the third lens is a convex surface;

the optical lens satisfies the following conditional expression: 1< TTL/f <1.4, wherein TTL represents the total optical length of the optical lens, and f represents the focal length of the optical lens;

the optical lens satisfies the following conditional expression: 0.5< DM1/f1<1, wherein DM1 represents the maximum effective aperture of the first lens and f1 represents the focal length of the first lens.

2. The optical lens of claim 1, wherein the third lens has negative optical power and the optical lens satisfies the conditional expression: -10< f3/f < -2, wherein f3 represents the focal length of the third lens.

3. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: IH/f <0.24, wherein IH represents the actual half-image height of the optical lens.

4. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 5< TTL/IH <7, wherein IH represents the actual half-image height of the optical lens.

5. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: f/EPD <2.0, wherein EPD represents an entrance pupil diameter of the optical lens.

6. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: -1.3< f1/f2< -0.1, wherein f1 represents the focal length of the first lens and f2 represents the focal length of the second lens.

7. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.5< BFL/TTL <0.6, wherein BFL represents the back focal length of the optical lens.

8. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 2< CT1/CT12<3,1< CT2/CT23<2, wherein CT1 represents a center thickness of the first lens, CT2 represents a center thickness of the second lens, CT12 represents an air space on an optical axis of the first lens and the second lens, and CT23 represents an air space on an optical axis of the second lens and the third lens.

9. The optical lens according to claim 1, wherein the optical lens satisfies a conditional expression: 0.1< R3/R4<1, wherein R3 represents a radius of curvature of the light exit surface of the second lens, and R4 represents a radius of curvature of the light entrance surface of the second lens.

10. A near-eye display system, comprising:

an image source for emitting an optical signal, the optical signal comprising image information;

the optical lens according to any one of claims 1 to 9, wherein the optical lens is disposed in a light-emitting direction of the image source, and the third lens is disposed closer to the image source than the first lens, and the optical lens is configured to modulate an optical signal emitted from the image source; and

the optical waveguide piece is arranged on one side, away from the image source, of the optical lens and is used for transmitting the optical signals modulated by the optical lens.