Optical lens and near-to-eye display device

Abstract

The invention provides an optical lens and a near-to-eye display device, and the optical lens is composed of eight lenses which sequentially comprise a first group with positive focal power, a second group with positive focal power, and a third group with negative focal power from a human eye entrance pupil side to an image source side along the reverse direction of light transmission. The first group sequentially comprises a first lens with positive focal power and a second lens with focal power along the reverse direction of light transmission; the second group sequentially comprises a third lens with positive focal power, a fourth lens with positive focal power, a fifth lens with positive focal power and a sixth lens with positive focal power along the reverse direction of light transmission; and the third group sequentially comprises a seventh lens with focal power and an eighth lens with focal power along the reverse direction of light transmission. The optical lens and the near-to-eye display device provided by the invention have the advantage of excellent imaging quality through specific surface shape arrangement and reasonable focal power distribution.

Description

Technical Field

[0001] The present invention relates to the technical field of imaging lenses, and in particular to an optical lens and a near-eye display device. Background Art

[0002] Virtual reality (VR) technology has developed rapidly in recent years and has become one of the important areas of scientific and technological innovation. At present, the virtual reality industry is showing a booming development trend. It is not only widely used in consumer fields such as entertainment and games, but also shows great potential in education, medical, industrial, military and other industries. VR devices transmit the information of the display screen to the human eye through optical lenses, and magnify the displayed information several times, so that users can experience an immersive viewing experience. On the one hand, the current VR head-mounted display devices are developing in the direction of comfort and high imaging quality; on the other hand, VR head-mounted display devices can also be compatible with other devices for multimodal experience. In order to meet these requirements, the optical system needs to achieve technical indicators such as high imaging quality, large exit pupil distance, and large field of view at the same time. Therefore, meeting the above optical performance at the same time brings great challenges to the design and aberration optimization of the optical system. Summary of the invention

[0003] In view of the above problems, an object of the present invention is to provide an optical lens and a near-eye display device having the advantage of excellent imaging quality.

[0004] The technical solution adopted by the present invention is: An optical lens, composed of eight lenses, which sequentially include: a first group with positive optical power, a second group with positive optical power, and a third group with negative optical power from the entrance pupil side of a human eye to the image source side along the reverse direction of light transmission; The first group is composed of a first lens with positive refractive power and a second lens with positive refractive power in sequence along the reverse direction of light transmission; The second group is composed of a third lens with positive focal power, a fourth lens with positive focal power, a fifth lens with positive focal power, and a sixth lens with positive focal power in sequence along the reverse direction of light transmission; The third group is composed of a seventh lens having optical power and an eighth lens having optical power in sequence along the reverse direction of light transmission; The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens each include a light incident surface close to the image source side and a light exit surface close to the entrance pupil side of the human eye; The exit pupil distance ED of the optical lens and the effective focal length f of the optical lens satisfy: 0.5 <ED / f<0.95。

[0005] The present invention also provides a near-eye display device, which includes, in sequence along the direction of light signal transmission: an image source and the above-mentioned optical lens; the image source is used to emit a light signal, and the light signal includes image information; the optical lens is arranged in the light emitting direction of the image source, and the eighth lens is arranged closer to the image source than the first lens, and the optical lens is used to modulate the light signal emitted by the image source and transmit it to the human eye.

[0006] Compared with the prior art, the optical lens provided by the present invention has a large exit pupil distance and a large field of view through a specific surface shape setting and a reasonable optical focal length distribution. The large field of view can provide a wide field of view display effect, bringing a better experience to users. At the same time, the optical lens also has a larger image surface and a higher resolution, which can match a monocular 4K high-definition display to achieve high-definition imaging quality, improve imaging quality, and bring users an excellent sensory experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 It is a schematic diagram of the structure of a near-eye display device provided in an embodiment of the present invention.

[0008] Figure 2 Schematic diagram of the structure of the optical lens provided in Example 1 of the present invention.

[0009] Figure 3 This is a point diagram of the optical lens provided in Example 1 of the present invention.

[0010] Figure 4 This is an MTF curve diagram of the optical lens provided in Example 1 of the present invention.

[0011] Figure 5 Schematic diagram of the structure of the optical lens provided in Example 2 of the present invention.

[0012] Figure 6 This is a point diagram of the optical lens provided in Example 2 of the present invention.

[0013] Figure 7 This is an MTF curve diagram of the optical lens provided in Example 2 of the present invention.

[0014] Figure 8 Schematic diagram of the structure of the optical lens provided in Example 3 of the present invention.

[0015] Fig. 9 This is a point diagram of the optical lens provided in Example 3 of the present invention.

[0016] Fig.10This is an MTF curve diagram of the optical lens provided in Example 3 of the present invention.

[0017] Fig.11 This is a schematic diagram of the structure of the optical lens provided in Example 4 of the present invention.

[0018] Fig.12 This is a point diagram of the optical lens provided in Example 4 of the present invention.

[0019] Fig.13 This is an MTF curve diagram of the optical lens provided in Example 4 of the present invention.

[0020] Fig.14 This is a schematic diagram of the structure of the optical lens provided in Example 5 of the present invention.

[0021] Fig.15 This is a point diagram of the optical lens provided in Example 5 of the present invention.

[0022] Fig.16 This is an MTF curve diagram of the optical lens provided in Example 5 of the present invention.

[0023] Fig.17 This is a schematic diagram of the structure of the optical lens provided in Example 6 of the present invention.

[0024] Fig.18 This is a point diagram of the optical lens provided in Example 6 of the present invention.

[0025] Fig.19 This is an MTF curve diagram of the optical lens provided in Example 6 of the present invention.

[0026] Fig. 20 This is a schematic diagram of the optical path of the near-eye display device provided in Example 7 of the present invention.

[0027] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0028] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the embodiments of the present application, and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0029] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0030] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0031] In this article, the paraxial region refers to the region 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.

[0032] It should also be understood that the terms "comprises", "including", "having", "includes" and / or "comprising", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0033] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0034] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0035] The present invention provides an optical lens, which is used to modulate the light signal emitted by the image source and transmit it to the entrance pupil side of the human eye. The optical lens is arranged in the light emitting direction of the image source, that is, the emission surface of the image source is the light emitting side of the light signal. The image source emits light, and the optical lens can correct the light emitted by the image source to reduce or eliminate various aberrations, and observe a high-definition magnified virtual image on the human eye side.

[0036] Specifically, the optical lens is composed of eight lenses, which successively include, along the reverse direction of light transmission (i.e., from the entrance pupil side of the human eye to the image source): a first group with positive optical power, a second group with positive optical power, and a third group with negative optical power.

[0037] Among them, the first group successively includes, along the reverse direction of light transmission: a first lens with positive optical power and a second lens with optical power. The second group successively includes, along the reverse direction of light transmission: a third lens with positive optical power, a fourth lens with positive optical power, a fifth lens with positive optical power, and a sixth lens with positive optical power. The third group successively includes, along the reverse direction of light transmission: a seventh lens with optical power and an eighth lens with optical power; the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens each include an incident light surface close to the image source side and an exit light surface close to the entrance pupil side of the human eye. It can be understood that the surface of each lens close to the image source is called the incident light surface of the lens, and the surface of each lens close to the entrance pupil side of the human eye is called the exit light surface of the lens. It should be noted that the position of the entrance pupil of the human eye is the aperture stop of the optical lens. When the human eye is at the aperture stop position, the human eye can observe the best imaging effect.

[0038] In some embodiments, the first lens has positive optical power, the exit light surface of the first lens is convex, and the incident light surface of the first lens can be concave or convex. The second lens has optical power, the exit light surface of the second lens is convex, and the incident light surface of the second lens can be concave or convex. The third lens has positive optical power, the exit light surface of the third lens is convex, and the incident light surface of the third lens can be concave or convex. The fourth lens has positive optical power, the exit light surface of the fourth lens is convex, and the incident light surface of the fourth lens can be concave or convex. The fifth lens has positive optical power, the exit light surface of the fifth lens is convex, and the incident light surface of the fifth lens can be concave or convex. The sixth lens has positive optical power, the exit light surface of the sixth lens is convex, and the incident light surface of the sixth lens can be concave or convex. The seventh lens has optical power, the exit light surface of the seventh lens is convex, and the incident light surface of the seventh lens can be concave or convex. The eighth lens has optical power, the exit light surface of the eighth lens can be concave or convex, and the incident light surface of the eighth lens is concave.

[0039] In some embodiments, the exit pupil distance ED of the optical lens and the effective focal length f of the optical lens satisfy: 0.5 < ED / f < 0.95; the exit pupil distance ED of the optical lens satisfies: 24 mm < ED < 26 mm. The exit pupil distance ED represents the distance on the optical axis from the entrance pupil side of the human eye to the exit light surface of the first lens. Meeting the above conditions can ensure a large entrance pupil distance while achieving a large field of view, have enough space to accommodate the matching of other devices (such as an eye movement camera, self-matching myopia lenses, etc.), reduce the dizziness feeling when the human eye wears it, and improve the sensory experience.

[0040] In some embodiments, the length IH of the display area of the image source that the optical lens can match and the effective focal length f of the optical lens satisfy: 0.75 < IH / f < 1.2. Meeting the above conditions can enable the optical lens to match a larger-sized display screen to achieve high-definition imaging, bringing an excellent sensory experience to users. At the same time, it is beneficial to achieve the telephoto performance of the lens, being able to better present larger local details, making the picture more concentrated and compact, thus meeting the visual experience of the human eye.

[0041] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 2 < f1 / f < 11; the effective focal length f of the optical lens and the curvature radius R1 of the light-emitting surface of the first lens satisfy: 1 < R1 / f < 22. Meeting the above conditions, the first lens close to the entrance pupil side of the human eye has a positive optical power, which can effectively converge light, so that the outgoing light enters the human eye observation area at a relatively parallel angle of view. While ensuring a large eye movement range of the system, it provides a better immersive experience for users.

[0042] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 4 < f3 / f < 17. Meeting the above conditions, the third lens can have an appropriate positive optical power, which can further converge light, making the light enter the system at a relatively gentle angle of view, reducing the difficulty of correcting aberration and distortion, and improving the overall imaging quality.

[0043] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 2 < f4 / f < 11; the effective focal length f of the optical lens and the curvature radius R7 of the light-emitting surface of the fourth lens satisfy: 1 < R7 / f < 15. Meeting the above conditions is beneficial to converging the light emitted from the image source side, reducing the divergence degree of the light, and thus entering the human eye at an angle of view close to parallel, ensuring a large field of view while improving the overall imaging quality.

[0044] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 2.5 < f5 / f < 9.5; the effective focal length f of the optical lens and the curvature radius R9 of the light-emitting surface of the fifth lens satisfy: 2 < R9 / f < 23. Meeting the above conditions is beneficial to the convergence of light, enabling the light emitted from the image source side to smoothly enter the rear optical system, reducing the difficulty of correcting various aberrations, and better realizing the high-quality imaging of the lens.

[0045] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1 < f6 / f < 17; the effective focal length f of the optical lens and the radius of curvature R11 of the light-emitting surface of the sixth lens satisfy: 0.6 < R11 / f < 6. Satisfying the above conditions is beneficial to converging the light rays emitted from the image source side, reducing the divergence degree of the light rays, so as to enter the human eye at an angle close to parallel, ensuring a large field of view while improving the overall imaging quality.

[0046] In some embodiments, the clear aperture semi-diameter DM11 of the light-emitting surface of the first lens and the clear aperture semi-diameter DM82 of the light-incident surface of the eighth lens satisfy: 1 < DM11 / DM82 < 1.3. Satisfying the above conditions, by reasonably setting the aperture relationship of the first and last lenses, the light rays emitted by the display screen can enter the human eye observation area at a relatively parallel and wide angle, ensuring a large eye movement range of the system while providing a better immersive experience for the user.

[0047] In some embodiments, the combined focal length fa of the first group and the effective focal length f of the optical lens satisfy: 1 < fa / f < 45. Satisfying the above conditions is beneficial to converging the light rays emitted from the image source side, reducing the divergence degree of the light rays, so as to enter the human eye at an angle close to parallel, ensuring a large field of view while improving the overall imaging quality.

[0048] In some embodiments, the combined focal length fb of the second group and the effective focal length f of the optical lens satisfy: 0.8 < fb / f < 1.8. Satisfying the above conditions is beneficial to the smooth transition of light rays, and at the same time corrects various aberrations of the optical lens, improving the imaging quality of the optical lens.

[0049] In some embodiments, the combined focal length fc of the third group and the effective focal length f of the optical lens satisfy: -2.5 < fc / f < -0.5. Satisfying the above conditions can greatly diverge the light rays emitted from the image source side to increase the area of the projected virtual image, providing a better immersive experience for the user.

[0050] In some embodiments, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.25 < TTL / f < 1.8; the overall optical length TTL of the optical lens and the display area length IH of the image source that the optical lens can match satisfy: 1.4 < TTL / IH < 1.9. Satisfying the above conditions can make the lens have a relatively compact system and at the same time have a large image plane, be able to match a large-size 4K high-definition display screen to achieve high-definition imaging, and bring an excellent sensory experience to the user.

[0051] In some embodiments, the effective focal length f of the optical lens and the radius of curvature R3 of the light-emitting surface of the second lens satisfy: 2 < R3 / f < 8. Meeting the above conditions can reasonably set the surface type of the second lens, which is beneficial to the smooth transition of light and reduces the difficulty of aberration correction.

[0052] In some embodiments, the effective focal length f of the optical lens and the radius of curvature R13 of the light-emitting surface of the seventh lens satisfy: 0.6 < R13 / f < 3. Meeting the above conditions can reasonably set the surface type of the seventh lens, which is beneficial to the smooth transition of light and reduces the difficulty of aberration correction.

[0053] In some embodiments, the effective focal length f of the optical lens and the radius of curvature R16 of the light-incident surface of the eighth lens satisfy: 0.3 < R16 / f < 9. Meeting the above conditions, by reasonably setting the surface type of the eighth lens, light emitted from a large-size image source (display screen) can be received to a greater extent, improving the matching degree between the lens and the large-size display screen.

[0054] In some embodiments, the sum ∑CT of the central thicknesses of the first lens to the eighth lens along the optical axis respectively and the sum ∑AT of the distances between any two adjacent lenses of the first lens to the eighth lens on the optical axis satisfy: 2.5 < ∑CT / ∑AT < 19. Meeting the above conditions can make the structure of the lens more compact, which is beneficial to the miniaturization of the lens.

[0055] In some embodiments, the optical lens satisfies the conditional formula: 48mm < TTL < 65mm; 28mm < f < 45mm; 68° < FOV < 72°, 34mm < IH < 35mm; where TTL represents the overall optical length of the optical lens, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, and IH represents the display area length of the image source that the optical lens can match. Meeting the above conditions indicates that the optical lens provided by the embodiments of the present invention has the advantages of long focal length performance, large field of view angle, small overall length, and being able to match a 4K high-definition display screen to achieve the viewing effect of a giant screen image.

[0056] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. Additionally, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected due to the low dispersion characteristic of the glass itself. The first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, and eighth lens of the present invention can all be made of glass or plastic.

[0057] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens may be spherical lenses or aspherical lenses. Compared with spherical structures, aspherical structures can effectively reduce the aberration of the optical lens, thereby reducing the number of lenses and reducing the size of lenses, and better realizing miniaturization of lenses. More specifically, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens of the present invention may all be aspherical lenses.

[0058] In various embodiments of the present invention, when the lens is an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equations: ; Among them, z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the surface vertex, K is the quadratic surface coefficient, B, C, D, E, F, G, and H are the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surface coefficients respectively.

[0059] In addition, the present invention also provides a near-eye display device, which includes, in sequence along the direction of light signal transmission: an image source and the above-mentioned optical lens; the image source is used to emit a light signal, and the light signal includes image information; the optical lens is arranged in the light emitting direction of the image source, and the eighth lens is arranged closer to the image source than the first lens, and the optical lens is used to modulate the light signal emitted by the image source and transmit it to the human eye.

[0060] The present invention is further described below in multiple embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are different. For specific differences, please refer to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any other changes, substitutions, combinations or simplifications that do not deviate from the innovative points of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

[0061] Example 1 See also Figure 1 , which is a schematic diagram of the structure of a near-eye display device 700 provided in an embodiment of the present invention, please refer to Figure 2 , which is a schematic diagram of the structure of the optical lens 100 provided in Embodiment 1 of the present invention, is used to modulate the optical signal emitted by the image source 10 and transmit it to the entrance pupil side of the human eye. The optical lens 100 is arranged in the light emitting direction of the image source 10, that is, the emitting surface of the image source 10 is the light emitting side of the optical signal. Figure 2It can be seen that the optical lens 100 is sequentially provided with: an aperture ST, a first group with positive optical power, a second group with positive optical power, and a third group with negative optical power along the reverse direction of light transmission (i.e., from the entrance pupil side of the human eye to the image source surface).

[0062] The first group includes a first lens L1 and a second lens L2; ​​the second group includes a third lens L3, a fourth lens L4, a fifth lens L5 and a sixth lens L6; the third group includes a seventh lens L7 and an eighth lens L8.

[0063] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7 and the eighth lens L8 each include a light entrance surface and a light exit surface, and the light entrance surface and the light exit surface are arranged on the surface of each lens opposite to each other. It can be understood that the surface of each lens close to the image source 10 is called the light entrance surface of the lens, and the surface of each lens close to the entrance pupil side of the human eye is called the light exit surface of the lens. The aperture is the entrance pupil of the imaging of this optical system, and the human eye is at the aperture position, so that the human eye can observe the best imaging effect.

[0064] Specifically, the first lens L1 has positive refractive power, a light exiting surface S1 of the first lens is a convex surface, and a light incident surface S2 of the first lens is a concave surface; The second lens L2 has negative optical power, a light exiting surface S3 of the second lens is a convex surface, and a light incident surface S4 of the second lens is a concave surface; The third lens L3 has positive refractive power, a light exiting surface S5 of the third lens is a convex surface, and a light incident surface S6 of the third lens is a convex surface; The fourth lens L4 has positive refractive power, a light exiting surface S7 of the fourth lens is a convex surface, and a light incident surface S8 of the fourth lens is a concave surface at the near optical axis; The fifth lens L5 has positive refractive power, a light exiting surface S9 of the fifth lens L5 is a convex surface, and a light incident surface S10 of the fifth lens L5 is a convex surface; The sixth lens L6 has positive refractive power, a light exiting surface S11 of the sixth lens L6 is a convex surface, and a light incident surface S12 of the sixth lens L6 is a concave surface; The seventh lens L7 has negative refractive power, a light exiting surface S13 of the seventh lens L7 is a convex surface, and a light incident surface S14 of the seventh lens L7 is a concave surface; The eighth lens L8 has negative refractive power, a light-exiting surface S15 of the eighth lens L8 is a concave surface, and a light-incident surface S16 of the eighth lens L8 is a concave surface.

[0065] In order to better realize the small size of the lens and reduce the cost while making the lens have a better imaging effect, the second lens L2 and the eighth lens L8 are both plastic aspherical lenses, and the first lens L1, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are all glass aspherical lenses.

[0066] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0067] Table 1-1 The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0068] Table 1-2 Please refer to Figure 3 , which is a spot diagram of the optical lens 100. The scale in the figure is 200 (unit: μm), the field of view angle (unit: degree) is shown above each figure, and the corresponding image height (unit: mm) is shown below. It can be seen from the figure that the RMS (root mean square radius of the diffuse spot) is less than 30um, and this smaller value indicates that the imaging quality of the optical lens 100 is good.

[0069] Please refer to Figure 4 , which is a graph of the MTF (modulation transfer function) of the optical lens 100, where the horizontal axis represents the spatial frequency (unit: lp / mm) and the vertical axis represents the modulation degree of the optical transfer function. As can be seen from the figure, the MTF value of the entire field of view is greater than 0.45 at 20lp / mm, and the curve is compact and falls smoothly, indicating that the optical lens 100 has good resolution and contrast, and the imaging at the edge position and the center position has good consistency.

[0070] Example 2 See also Figure 5 , which is a schematic diagram of the structure of the optical lens 200 provided in Embodiment 2 of the present invention. Compared with Embodiment 1, the main differences of this embodiment are: the eighth lens L8 has positive focal power; the light-emitting surface S15 of the eighth lens L8 is a convex surface; the first lens L1, the third lens L3, the fourth lens L4, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are glass aspherical lenses; the second lens L2 and the fifth lens L5 are plastic aspherical lenses; and the optical parameters such as the curvature radius, lens thickness, and material of each lens surface are different.

[0071] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0072] Table 2-1 The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0073] Table 2-2 from Figure 6 As can be seen from the figure, the RMS (root mean square radius of the diffuse spot) is less than 30 um. This smaller value indicates that the imaging quality of the optical lens 200 is better.

[0074] from Figure 7 It can be seen that the MTF value of the whole field of view is greater than 0.4 at 20lp / mm, and the curve is compact and the decline is smooth, which means that the optical lens 200 has good resolution and contrast, and the imaging at the edge position and the center position has good consistency.

[0075] Example 3 See also Figure 8 , which is a schematic diagram of the structure of the optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, the main differences of this embodiment are: the second lens L2 has positive focal power; the seventh lens L7 has positive focal power; the light incident surface S2 of the first lens L1 is convex; the light incident surface S4 of the second lens L2 is convex; the light incident surface S6 of the third lens L3 is concave; the light incident surface S8 of the fourth lens L4 is convex; the light incident surface S10 of the fifth lens L5 is concave; the light incident surface S12 of the sixth lens L6 is convex; the first lens L1, the third lens L3, the sixth lens L6, and the seventh lens L7 are glass aspherical lenses; the second lens L2, the fourth lens L4, the fifth lens L5, and the eighth lens L8 are plastic aspherical lenses; the optical parameters such as the curvature radius, lens thickness, and material of each lens surface are different.

[0076] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0077] Table 3-1 The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0078] Table 3-2 from Fig. 9 As can be seen from the figure, the RMS (root mean square radius of the diffuse spot) is less than 30 um. This smaller value indicates that the imaging quality of the optical lens 300 is better.

[0079] from Fig.10It can be seen that the MTF value of the whole field of view is greater than 0.4 at 20lp / mm, and the curve is compact and the decline is smooth, which means that the optical lens 300 has good resolution and contrast, and the imaging at the edge position and the center position has good consistency.

[0080] Example 4 See also Fig.11 , which is a schematic diagram of the structure of an optical lens 400 provided in Example 4 of the present invention. Compared with Example 1, the main differences of this embodiment are: the second lens L2 has positive focal power; the seventh lens L7 has positive focal power; the light incident surface S2 of the first lens L1 is a convex surface; the light incident surface S4 of the second lens L2 is a convex surface; the light incident surface S12 of the sixth lens L6 is a convex surface; the light incident surface S14 of the seventh lens L7 is a convex surface; the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7 and the eighth lens L8 are all plastic aspherical lenses; the optical parameters such as the curvature radius, lens thickness, material and the like of the surface of each lens are different.

[0081] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0082] Table 4-1 The surface parameters of the aspheric lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0083] Table 4-2 from Fig.12 As can be seen from the figure, the RMS (root mean square radius of the diffuse spot) is less than 30um. This smaller value indicates that the imaging quality of the optical lens 400 is better.

[0084] from Fig.13 It can be seen that the MTF value of the whole field of view is greater than 0.3 at 20lp / mm, and the curve is compact and the decline is smooth, which means that the optical lens 400 has good resolution and contrast, and the imaging at the edge position and the center position has good consistency.

[0085] Example 5 See also Fig.14, which is a schematic diagram of the structure of an optical lens 500 provided in Example 5 of the present invention. Compared with Example 1, the main differences of this embodiment are: the second lens L2 has positive focal power; the seventh lens L7 has positive focal power; the light incident surface S2 of the first lens L1 is a convex surface; the light incident surface S4 of the second lens L2 is a convex surface; the light incident surface S8 of the fourth lens L4 is a convex surface; the light incident surface S10 of the fifth lens L5 is a concave surface; the light incident surface S14 of the seventh lens L7 is a convex surface; the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7 and the eighth lens L8 are all plastic aspherical lenses; the optical parameters such as the curvature radius, the lens thickness, and the material of each lens surface are different.

[0086] The relevant parameters of each lens in the optical lens 500 in Example 5 are shown in Table 5-1.

[0087] Table 5-1 The surface parameters of the aspheric lens of the optical lens 500 in Example 5 are shown in Table 5-2.

[0088] Table 5-2 from Fig.15 As can be seen from the figure, the RMS (root mean square radius of the diffuse spot) is less than 30um. This smaller value indicates that the imaging quality of the optical lens 500 is better.

[0089] from Fig.16 It can be seen that the MTF value of the whole field of view is greater than 0.58 at 20lp / mm, and the curve is compact and the decline is smooth, indicating that the optical lens 500 has good resolution and contrast, and the imaging at the edge position and the center position has good consistency.

[0090] Example 6 See also Fig.17 , which is a schematic diagram of the structure of an optical lens 600 provided in Example 6 of the present invention. Compared with Example 1, the main differences of this embodiment are: the second lens L2 has positive focal power; the seventh lens L7 has positive focal power; the light incident surface S2 of the first lens L1 is a convex surface; the light incident surface S4 of the second lens L2 is a convex surface; the light incident surface S8 of the fourth lens L4 is a convex surface; the light incident surface S10 of the fifth lens L5 is a concave surface; the eighth lens L8 is a plastic aspheric lens; the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are all glass aspheric lenses; the optical parameters such as the curvature radius, lens thickness, and material of each lens surface are different.

[0091] The relevant parameters of each lens in the optical lens 600 in Example 6 are shown in Table 6-1.

[0092] Table 6-1 The surface parameters of the aspheric lens of the optical lens 600 in Example 6 are shown in Table 6-2.

[0093] Table 6-2 from Fig.18 As can be seen from the figure, the RMS (root mean square radius of the diffuse spot) is less than 30um. This smaller value indicates that the imaging quality of the optical lens 600 is better.

[0094] from Fig.19 It can be seen that the MTF value of the whole field of view is greater than 0.6 at 20lp / mm, and the curve is compact and the decline is smooth, indicating that the optical lens 600 has good resolution and contrast, and the imaging at the edge position and the center position has good consistency.

[0095] Please refer to Table 7, which shows the optical characteristics corresponding to the above-mentioned embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the maximum field of view FOV, the entrance pupil diameter EPD, the exit pupil distance ED, the virtual image distance VID, and the display area length IH of the image source that the optical lens can match, and the numerical values ​​corresponding to each conditional expression in each embodiment.

[0096] Table 7 In summary, the optical lens provided by the present invention has at least the following advantages: (1) Through specific surface shape settings and reasonable optical focal length distribution, the optical lens has a larger field of view angle and a large exit pupil distance. The larger field of view angle can provide a wide field of view display effect, giving users a better experience. The lens has a telephoto characteristic, which can better present larger local details, making the picture more focused and compact, thus meeting the needs.

[0097] (2) The optical lens also has a larger image surface and higher resolution, which can be matched with a monocular 4K high-definition display to achieve high-definition imaging quality, improve imaging quality, and bring users an excellent sensory experience.

[0098] Example 7 See also Fig. 20, which is a schematic diagram of an optical path in a near-eye display device 700 provided by an embodiment of the present invention, the near-eye display device 700 includes an image source 10, an optical lens (such as the optical lens 100) in any of the aforementioned embodiments of the present application, and the optical lens is located between the human eye 20 and the image source 10. The image information emitted from the image source 10 enters the human eye 20 through the optical lens to form an image, and the human eye 20 can observe a high-definition magnified virtual image, which has an extremely realistic sensory experience.

[0099] The image source 10 is used to emit a light signal, and the light signal includes image information. Specifically, the image source 10 can be one of a display screen such as Micro LED, OLED, LCD, LCOS, M-OLED, etc. More specifically, in this embodiment, the image source 10 can use a 1.35-inch Micro OLED display screen, which can provide high-definition image information for the optical lens.

[0100] The optical lens is arranged in the light emitting direction of the image source 10 , and the eighth lens in the optical lens is arranged closer to the image source 10 than the first lens. The optical lens is used to modulate the light signal emitted by the image source 10 and transmit it to the human eye 20 .

[0101] The near-eye display device 700 may be VR glasses, VR helmets, head-mounted display devices, etc. Since the above optical lens has a large exit pupil distance, a large field of view angle, and a telephoto characteristic, the large field of view angle can provide a wide field of view display effect, improve the user's sense of immersion, and thus bring a better experience to the user. The lens has a telephoto characteristic, which can better present larger local details, making the picture more focused and compact, thereby meeting the needs. At the same time, the optical lens also has a larger image surface, a higher resolution, and a longer virtual image distance. The light signal image modulated by the optical lens is bright and clear, with better effects, and the picture projected to the human eye is clearer and wider. Therefore, the near-eye display device equipped with the optical lens has at least the characteristics of a wide field of view and high image quality, which can effectively improve the user's visual experience and comfort.

[0102] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0103] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An optical lens, consisting of eight lenses, characterized in that: The optical components include: a first group with positive optical power, a second group with positive optical power, and a third group with negative optical power, from the entrance pupil side of the human eye to the image source side in the reverse direction of light transmission; The first group is composed of a first lens with positive refractive power and a second lens with positive refractive power in sequence along the reverse direction of light transmission; The second group is composed of a third lens with positive focal power, a fourth lens with positive focal power, a fifth lens with positive focal power, and a sixth lens with positive focal power in sequence along the reverse direction of light transmission; The third group is composed of a seventh lens having optical power and an eighth lens having optical power in sequence along the reverse direction of light transmission; The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens each include a light incident surface close to the image source side and a light exit surface close to the entrance pupil side of the human eye; The exit pupil distance ED of the optical lens and the effective focal length f of the optical lens satisfy: 0.5 <ED / f<0.95。 2. The optical lens according to claim 1, characterized in that: The display area length IH of the image source that the optical lens can match and the effective focal length f of the optical lens satisfy: 0.75 <IH / f<1.2。 3. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: <f1 / f<11。 4. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: <f3 / f<17。 5. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: <f4 / f<11。 6. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 2.5 <f5 / f<9.5。 7. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 1 <f6 / f<17。 8. The optical lens according to claim 1, characterized in that: The semi-aperture DM11 of the light exiting surface of the first lens and the semi-aperture DM82 of the light incident surface of the eighth lens satisfy: 1 <DM11 / DM82<1.3。 9. The optical lens according to claim 1, characterized in that: The combined focal length fa of the first group and the effective focal length f of the optical lens satisfy: 1 <fa / f<45。 10. The optical lens according to claim 1, characterized in that: The combined focal length fb of the second group and the effective focal length f of the optical lens satisfy: 0.8 <fb / f<1.8。 11. The optical lens according to claim 1, characterized in that: The combined focal length fc of the third group and the effective focal length f of the optical lens satisfy: -2.5 <fc / f<-0.5。 12. The optical lens according to claim 1, characterized in that: The light exit surface of the first lens is convex; the light exit surface of the second lens is convex; the light exit surface of the third lens is convex; the light exit surface of the fourth lens is convex; the light exit surface of the fifth lens is convex; the light exit surface of the sixth lens is convex; the light exit surface of the seventh lens is convex; and the light incident surface of the eighth lens is concave.

13. A near-eye display device, characterized in that: The optical signal transmission direction includes: an image source, an optical lens according to any one of claims 1 to 12; The image source is used to emit a light signal, and the light signal includes image information; The optical lens is arranged in the light emitting direction of the image source, and the eighth lens is arranged closer to the image source than the first lens. The optical lens is used to modulate the light signal emitted by the image source and transmit it to the human eye.

Images