Optical lens and near-to-eye display device

Abstract

The invention provides an optical lens and near-to-eye display equipment. The optical lens sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens in the reverse direction of light transmission. The first lens has positive focal power; the second lens has negative focal power, and the light emitting surface of the second lens is a concave surface; the third lens has positive focal power, the emergent surface of the third lens is a convex surface, and the incident surface of the third lens is a convex surface; the fourth lens has focal power, the light-emitting surface of the fourth lens is a concave surface near the optical axis, and the light-incident surface of the fourth lens is a convex surface near the optical axis; the fifth lens has focal power; the sixth lens has positive focal power, and the light emitting surface of the sixth lens is a convex surface; the seventh lens has negative focal power, the light-out surface of the seventh lens is a convex surface, and the light-in surface of the seventh lens is a concave surface. 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] With the continuous advancement of optoelectronic devices and communication technology, virtual reality (VR) technology, as the forefront of the new generation of information technology, has achieved leapfrog development, and its forms and types are becoming increasingly diverse, and it is constantly being used in military, medical, education and consumer fields. Among them, head-mounted display devices usually transmit and amplify the information on the display screen through an optical system, and finally output it to the human eye. Therefore, the human eye receives the enlarged virtual image of the display screen, thereby achieving the purpose of large-screen viewing. At present, head-mounted display devices are developing in the direction of being more miniaturized, thinner, easier to wear, and lighter. At the same time, large field of view, low distortion and visual comfort have also become key evaluation indicators for the quality of head-mounted displays. Large field of view brings better immersion, low distortion and high image quality determine the visual comfort.

[0003] In order to meet these requirements, the optical system needs to achieve large field of view, low distortion, high image quality and other indicators at the same time. However, an increase in the field of view often leads to an increase in distortion. Therefore, meeting the above optical performance at the same time poses a huge challenge to the design of the optical system and the optimization of aberrations. Summary of the invention

[0004] 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.

[0005] The technical solution adopted by the present invention is: An optical lens is composed of seven lenses, which sequentially include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens from the human eye entrance pupil side to the image source side along the reverse direction of light transmission; each of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens includes a light incident surface close to the image source side and a light exit surface close to the human eye entrance pupil side; the first lens has a positive optical power; the second lens has a negative optical power, and the light exit surface of the second lens is concave; the third lens has a positive optical power, the light exit surface of the third lens is convex, and the light incident surface of the third lens is convex; the fourth lens has an optical power, the light exit surface of the fourth lens is concave near the optical axis, and the light incident surface of the fourth lens is convex near the optical axis; the fifth lens has an optical power; the sixth lens has a positive optical power, and the light exit surface of the sixth lens is convex; the seventh lens has a negative optical power, the light exit surface of the seventh lens is convex, and the light incident surface of the seventh lens is concave; wherein, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.2 < TTL / f < 3.2; the total optical length TTL of the optical lens and the display area length IH of the image source that the optical lens can match satisfy: 1.5 < TTL / IH < 2.2.

[0006] The present invention also provides a near-eye display device, which sequentially includes: an image source, and the above-mentioned optical lens along the light signal transmission direction; the image source is used for emitting a light signal, and the light signal includes image information; the optical lens is arranged in the light exit direction of the image source, and the seventh lens is arranged closer to the image source than the first lens, and the optical lens is used for modulating the light signal emitted by the image source and transmitting it to the human eye.

[0007] Compared with the prior art, the optical lens provided by the present invention, through specific surface shape settings and reasonable optical power distribution, enables the optical lens to have a large field of view angle. The large field of view angle can provide a wide-field display effect, bringing a better experience to users. At the same time, the optical lens also has a large image plane and high resolution, and can match a large-size 4K high-definition display screen to achieve the viewing effect of a giant screen image, improving the imaging quality and bringing an excellent sensory experience to users. Description of the Drawings

[0008] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, where: Figure 1 It is a schematic structural diagram of the near-eye display device provided in the embodiment of the present invention.

[0009] Figure 2 It is a schematic structural diagram of the optical lens provided in Embodiment 1 of the present invention.

[0010] Figure 3 This is a point diagram of the optical lens provided in Example 1 of the present invention.

[0011] Figure 4 This is an MTF curve diagram of the optical lens provided in Example 1 of the present invention.

[0012] Figure 5 This is a field curvature curve diagram of the optical lens provided in Example 1 of the present invention.

[0013] Figure 6 Schematic diagram of the structure of the optical lens provided in Example 2 of the present invention.

[0014] Figure 7 This is a point diagram of the optical lens provided in Example 2 of the present invention.

[0015] Figure 8 This is an MTF curve diagram of the optical lens provided in Example 2 of the present invention.

[0016] Fig. 9 This is a field curvature curve diagram of the optical lens provided in Example 2 of the present invention.

[0017] Fig.10 Schematic diagram of the structure of the optical lens provided in Example 3 of the present invention.

[0018] Fig.11 This is a point diagram of the optical lens provided in Example 3 of the present invention.

[0019] Fig.12 This is an MTF curve diagram of the optical lens provided in Example 3 of the present invention.

[0020] Fig.13 This is a field curvature curve diagram of the optical lens provided in Example 3 of the present invention.

[0021] Fig.14 This is a schematic diagram of the structure of the optical lens provided in Example 4 of the present invention.

[0022] Fig.15 This is a point diagram of the optical lens provided in Example 4 of the present invention.

[0023] Fig.16 This is an MTF curve diagram of the optical lens provided in Example 4 of the present invention.

[0024] Fig.17 This is a field curvature curve diagram of the optical lens provided in Example 4 of the present invention.

[0025] Fig.18 This is a schematic diagram of the structure of the optical lens provided in Example 5 of the present invention.

[0026] Fig.19 This is a point diagram of the optical lens provided in Example 5 of the present invention.

[0027] Fig. 20 This is an MTF curve diagram of the optical lens provided in Example 5 of the present invention.

[0028] Fig.21 This is a field curvature curve diagram of the optical lens provided in Example 5 of the present invention.

[0029] Fig. 22 This is a schematic diagram of the optical path of the near-eye display device provided in Example 6 of the present invention.

[0030] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] Specifically, the optical lens is composed of seven lenses, which include the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens in the reverse direction of light transmission (i.e., from the entrance pupil side of the human eye to the image source side); the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens each include a light entrance surface close to the image source side and a light exit 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 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. It should be noted that the entrance pupil position of the human eye is the aperture of the optical lens. When the human eye is at the aperture position, the human eye can observe the best imaging effect.

[0040] In some embodiments, the first lens has a positive focal power. The light-emitting surface of the first lens can be concave or convex, and the light-incident surface of the first lens can be concave or convex. The second lens has a negative focal power. The light-emitting surface of the second lens is concave, and the light-incident surface of the second lens can be concave or convex. The third lens has a positive focal power. The light-emitting surface of the third lens is convex, and the light-incident surface of the third lens is convex. The fourth lens can have a positive or negative focal power. The light-emitting surface of the fourth lens is concave near the optical axis, and the light-incident surface of the fourth lens is convex near the optical axis. The fifth lens can have a positive or negative focal power. The light-emitting surface of the fifth lens can be concave or convex, and the light-incident surface of the fifth lens can be concave or convex. The sixth lens has a positive focal power. The light-emitting surface of the sixth lens is convex, and the light-incident surface of the sixth lens can be concave or convex. The seventh lens can have a negative focal power. The light-emitting surface of the seventh lens is convex, and the light-incident surface of the seventh lens is concave.

[0041] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.2 < TTL / f < 3.2; the total optical length TTL of the optical lens and the display area length IH of the image source that the optical lens can match satisfy: 1.5 < TTL / IH < 2.2. Meeting the above conditions can make the lens have a relatively compact system, and at the same time make the lens have a larger image plane, be able to match a larger-sized image source (display screen) to achieve high-definition imaging, and bring an excellent sensory experience to users.

[0042] In some embodiments, 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: 1.25 < IH / f < 1.7. Meeting the above conditions can make the optical lens match a larger-sized image source (display screen) to achieve high-definition imaging, bring an excellent sensory experience to users, and at the same time be beneficial to realizing the telephoto performance of the lens, being able to better present larger local details, making the picture more concentrated and compact, so as to meet the visual experience of the human eye.

[0043] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.2 < f1 / f < 5.5. Meeting the above conditions can converge light to a large extent, making the outgoing light better converge into the human eye observation area, and providing a better immersion experience for users while ensuring that the system provides a large eye movement range.

[0044] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3.5 < f2 / f < -0.6. Meeting the above conditions can appropriately slow down the turning degree of light, and diverge the light better into the human eye, so as to provide a wide-field display effect and improve the immersion of users.

[0045] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 2 < f3 / f < 7; the radius of curvature R5 of the light-emitting surface of the third lens and the radius of curvature R6 of the light-incident surface of the third lens satisfy: -15 < R5 / R6 < -1. Meeting 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 almost parallel viewing angle, ensuring a large viewing angle while improving the overall imaging quality.

[0046] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: 0.6 < f6 / f < 2.6. Meeting the above conditions is beneficial to the convergence of light rays, enabling the light rays emitted from the image source side to smoothly enter the rear optical system, reducing the correction difficulty of various aberrations, and better realizing the high-quality imaging of the lens.

[0047] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -6 < f7 / f < -0.8. Meeting 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 users.

[0048] In some embodiments, the radius of curvature R13 of the light-emitting surface of the seventh lens and the radius of curvature R14 of the light-incident surface of the seventh lens satisfy: 1.1 < R13 / R14 < 10. Meeting the above conditions, by reasonably setting the meniscus shape of the seventh lens, the light rays emitted from a large-size image source (display screen) can be received to a large extent, improving the matching degree between the lens and the large-size display screen.

[0049] In some embodiments, the back focal length BFL of the optical lens and the total optical length TTL of the optical lens satisfy: 0.16 < BFL / TTL < 0.26; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.45 < BFL / f < 0.65. Meeting the above conditions can make the lens have a large optical back focal length, which is beneficial to reducing the interference between different components and improving the yield. At the same time, it can enable the seventh lens to better and more comprehensively receive the light rays emitted from the large-size display screen, improving the imaging quality.

[0050] In some embodiments, the sum ∑CT of the central thicknesses of the first lens to the seventh lens along the optical axis respectively and the sum ∑AT of the distances between any two adjacent lenses of the first lens to the seventh lens on the optical axis satisfy: 9 < ∑CT / ∑AT < 35. Meeting the above conditions can make the structure of the lens more compact, which is beneficial to realizing the miniaturization of the lens.

[0051] In some embodiments, the combined focal length f345 of the third lens, the fourth lens, and the fifth lens and the effective focal length f of the optical lens satisfy: 0.9 < f345 / f < 6.8. Meeting the above conditions can effectively converge light, enabling the light to enter the system at a relatively gentle angle of view, reducing the difficulty of correcting aberration and distortion, and improving the overall imaging quality.

[0052] 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 < 0.8. The exit pupil distance ED represents the distance on the optical axis from the entrance pupil side of the human eye to the light-emitting surface of the first lens. Meeting the above conditions can ensure a relatively large entrance pupil distance while achieving a relatively large field of view angle, reducing the sense of dizziness when the human eye wears it, and improving the sensory experience.

[0053] In some embodiments, the effective focal length f of the optical lens, the maximum field of view angle FOV of the optical lens, and the display area length IH of the image source that the optical lens can match satisfy: 42° < (f × FOV) / IH < 58°. Meeting the above conditions can enable the lens to have a relatively large field of view angle while having a relatively large image plane, being able to match a relatively large-sized display screen to achieve high-definition imaging, and improving the user's sense of immersion.

[0054] In some embodiments, the curvature radius R7 of the light-emitting surface of the fourth lens and the curvature radius R8 of the light-incident surface of the fourth lens satisfy: 0.2 < R7 / R8 < 1.8. Meeting the above conditions can better correct the edge distortion and aberration of the lens, and improve the imaging quality of the lens.

[0055] In some embodiments, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: -2.5 < f1 / f2 < -1. Meeting the above conditions is conducive to the smooth transition of light, and at the same time corrects various aberrations of the optical lens, improving the imaging quality of the optical lens.

[0056] In some embodiments, the focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: -2.5 < f6 / f7 < -0.1. Meeting the above conditions can better converge the light emitted from the display screen, enabling the light to enter the subsequent system at a relatively gentle angle of view, reducing the difficulty of correcting aberration and distortion, and improving the overall imaging quality.

[0057] In some embodiments, the clear aperture semi-diameter DM11 of the light-emitting surface of the first lens and the clear aperture semi-diameter DM72 of the light-incident surface of the seventh lens satisfy: 0.58 < DM11 / DM72 < 0.82. Meeting the above conditions, by reasonably setting the aperture relationship of the first and last lenses, the light emitted from the display screen can enter the human eye observation area at a relatively parallel and wide angle of view. While ensuring that the system provides a relatively large eye movement range, it can also match a relatively large-sized 4K high-definition display screen to achieve high-definition imaging, and can provide a better sense of immersion experience for users.

[0058] In some embodiments, the optical lens satisfies the conditional formula: 50 mm < TTL < 72 mm; 18 mm < f < 28 mm; 63° < FOV < 75°; 33 mm < IH < 35 mm; 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 length of the display area 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 a long focal length, a large field of view angle, and the ability to match a display screen with a relatively large size (1.33 inches) to achieve the viewing effect of a giant screen image.

[0059] 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 by the low-dispersion characteristics of the glass itself. The first lens, the fourth lens, the fifth lens, and the seventh lens of the present invention can be made of glass or plastic; the second lens can be made of plastic; the third lens and the sixth lens can be made of glass.

[0060] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens can adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the first lens and the seventh lens of the present invention can adopt spherical or aspherical lenses, and the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens can all adopt aspherical lenses.

[0061] In various embodiments of the present invention, when the lens adopts an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equation: ; where z is the distance between the curved surface and the vertex of the curved surface in the optical axis direction, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the conic coefficient, and B, C, D, E, F, G, and H are the surface coefficients of the fourth order, sixth order, eighth order, tenth order, twelfth order, fourteenth order, and sixteenth order, respectively.

[0062] In addition, the present invention also provides a near-eye display device, which sequentially includes, along the optical signal transmission direction: an image source, and the above-mentioned optical lens; the image source is used for emitting an optical signal, and the optical signal includes image information; the optical lens is arranged in the light-emitting direction of the image source, and the seventh lens is arranged closer to the image source than the first lens, and the optical lens is used for modulating the optical signal emitted by the image source and transmitting it to the human eye.

[0063] 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.

[0064] Example 1 See also Figure 1 , which is a schematic diagram of the structure of a near-eye display device 600 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 2 It can be seen that the optical lens 100 is sequentially provided with the following components along the reverse direction of light transmission (i.e., from the entrance pupil side of the human eye to the image source side): the aperture ST, 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. 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 each include a light entrance surface close to the image source side and a light exit 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 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 the optical system, and the human eye is at the aperture position, so that the human eye can observe the best imaging effect.

[0065] 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 convex surface; The second lens L2 has negative optical power, a light exiting surface S3 of the second lens is a concave 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 negative optical power, a light exiting surface S7 of the fourth lens is concave at the near optical axis, and a light incident surface S8 of the fourth lens is convex; The fifth lens L5 has negative 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 concave 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 convex 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; 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 third lens L3 and the sixth lens L6 are both glass aspherical lenses, and the first lens L1, the second lens L2, the fourth lens L4, the fifth lens L5 and the seventh lens L7 are all plastic 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 400 (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) in the 0.9 field of view is less than 15um, 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 0.55 at 16lp / 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] Please refer to Figure 5 , which is a field curvature curve of the optical lens 100, indicating the degree of curvature of light in the meridian image plane and the sagittal image plane, the horizontal axis indicates the offset (unit: mm), and the vertical axis indicates the field angle (unit: °). It can be seen from the figure that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±2.5mm, indicating that the optical lens 100 can correct the field curvature well.

[0071] Example 2 See also Figure 6, which is a schematic diagram of the structure of the optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, the main differences of this embodiment are: the fourth lens L4 has positive focal power; the fifth lens L5 has positive focal power; the light exit surface S9 of the fifth lens L5 is a concave surface; the light incident surface S10 of the fifth lens L5 is a convex surface; the first lens L1, the third lens L3, and the sixth lens L6 are glass aspheric lenses; the second lens L2, the fourth lens L4, the fifth lens L5, and the seventh lens L7 are all plastic aspheric lenses; the optical parameters such as the curvature radius, lens thickness, and material of each lens surface are different.

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

[0073] Table 2-1 The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0074] Table 2-2 from Figure 7 It can be seen that the RMS (root mean square radius of the diffuse spot) in the 0.9 field of view is less than 15 um. This smaller value indicates that the imaging quality of the optical lens 200 is better.

[0075] from Figure 8 It can be seen that the MTF value of the whole field of view is greater than 0.68 at 16lp / 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.

[0076] from Fig. 9 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within -6mm~2mm, indicating that the optical lens 200 can correct the field curvature well.

[0077] Example 3 See also Fig.10 , 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 fifth lens L5 has positive focal power; the light incident surface S2 of the first lens L1 is concave; the light exit surface S9 of the fifth lens L5 is concave; the light incident surface S10 of the fifth lens L5 is convex; the light incident surface S12 of the sixth lens L6 is concave; the seventh lens L7 is a glass spherical lens; the second lens L2 is a plastic aspherical lens; the first lens L1, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are all glass aspherical lenses; the optical parameters such as the curvature radius, lens thickness, and material of each lens surface are different.

[0078] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0079] Table 3-1 The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0080] Table 3-2 from Fig.11 It can be seen that the RMS (root mean square radius of the diffuse spot) in the 0.9 field of view is less than 15um. This smaller value indicates that the imaging quality of the optical lens 300 is better.

[0081] from Fig.12 It can be seen that the MTF value of the whole field of view is greater than 0.58 at 16lp / 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.

[0082] from Fig.13 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±1.5 mm, indicating that the optical lens 300 can correct the field curvature well.

[0083] Example 4 See also Fig.14 , 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 fourth lens L4 has positive focal power; the fifth lens L5 has positive focal power; the light exit surface S1 of the first lens L1 is a concave surface; the light incident surface S4 of the second lens L2 is a convex surface; the light incident surface S10 of the fifth lens L5 is a convex surface; the light incident surface S12 of the sixth lens L6 is a concave surface; the first lens L1 and the seventh lens L7 are glass spherical lenses; the second lens L2 is a plastic aspherical lens; the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are all glass aspherical lenses; the optical parameters such as the curvature radius, lens thickness, and material of each lens surface are different.

[0084] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0085] Table 4-1 The surface parameters of the aspheric lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0086] Table 4-2 from Fig.15 It can be seen that the RMS (root mean square radius of the diffuse spot) in the 0.9 field of view is less than 15um. This small value indicates that the imaging quality of the optical lens 400 is better.

[0087] from Fig.16 It can be seen that the MTF value of the whole field of view is greater than 0.48 at 16lp / 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.

[0088] from Fig.17 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±1mm, indicating that the optical lens 400 can correct the field curvature well.

[0089] Example 5 See also Fig.18 , 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 fourth lens L4 has positive focal power; the fifth lens L5 has positive focal power; the light exit surface S1 of the first lens L1 is a concave surface; the light incident surface S4 of the second lens L2 is a convex surface; the light incident surface S10 of the fifth lens L5 is a convex surface; the light incident surface S12 of the sixth lens L6 is a concave surface; the first lens L1 and the seventh lens L7 are glass spherical lenses; the second lens L2 is a plastic aspherical lens; the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are all glass aspherical lenses; the optical parameters such as the curvature radius, lens thickness, and material of each lens surface are different.

[0090] The relevant parameters of each lens in the optical lens 500 in Example 5 are shown in Table 5-1.

[0091] Table 5-1 The surface parameters of the aspheric lens of the optical lens 500 in Example 5 are shown in Table 5-2.

[0092] Table 5-2 from Fig.19 It can be seen that the RMS (root mean square radius of the diffuse spot) in the 0.9 field of view is less than 15um. This small value indicates that the imaging quality of the optical lens 500 is good.

[0093] from Fig. 20It can be seen that the MTF value of the whole field of view is greater than 0.48 at 16lp / 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.

[0094] from Fig.21 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±1mm, indicating that the optical lens 500 can correct the field curvature well.

[0095] Please refer to Table 6, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the maximum field of view FOV, the back focal length BFL, and the display area length IH of the image source that the optical lens can match and the corresponding values ​​of each conditional expression in each embodiment.

[0096] Table 6 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 telephoto characteristics. 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 larger 4K high-definition display to achieve a giant screen image effect, improve imaging quality, and bring users an excellent sensory experience.

[0098] Example 6 See also Fig. 22 , which is a schematic diagram of an optical path in a near-eye display device 600 provided by an embodiment of the present invention, the near-eye display device 600 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 1.33-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 seventh 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 600 may be VR glasses, VR helmets, head-mounted display devices, etc. Since the above optical lens has a large field of view angle and telephoto characteristics, 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 and a higher resolution. 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. 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 seven lenses, characterized in that: It successively includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens from the side of the entrance pupil of the human eye to the side of the image source in the reverse direction of the light transmission; the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens each include an incident light surface close to the side of the image source and an emergent light surface close to the side of the entrance pupil of the human eye; The first lens has a positive optical power; The second lens has a negative optical power, and the emergent light surface of the second lens is a concave surface; The third lens has a positive optical power, the emergent light surface of the third lens is a convex surface, and the incident light surface of the third lens is a convex surface; The fourth lens has an optical power, the emergent light surface of the fourth lens is a concave surface near the optical axis, and the incident light surface of the fourth lens is a convex surface near the optical axis; The fifth lens has an optical power; The sixth lens has a positive optical power, and the emergent light surface of the sixth lens is a convex surface; The seventh lens has a negative optical power, the emergent light surface of the seventh lens is a convex surface, and the incident light surface of the seventh lens is a concave surface; Wherein, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2.2 < TTL / f < 3.2; The total optical length TTL of the optical lens and the display area length IH of the image source that the optical lens can match satisfy: 1.5 < TTL / IH < 2.

2.

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: 1.25 < IH / f < 1.

7.

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: 1.2 < f1 / f < 5.

5.

4. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3.5 < f2 / f < -0.

6.

5. 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: 2 < f3 / f < 7; the curvature radius R5 of the emergent light surface of the third lens and the curvature radius R6 of the incident light surface of the third lens satisfy: -15 < R5 / R6 < -1.

6. 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: 0.6 < f6 / f < 2.

6.

7. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -6 < f7 / f < -0.8; the curvature radius R13 of the emergent light surface of the seventh lens and the curvature radius R14 of the incident light surface of the seventh lens satisfy: 1.1 < R13 / R14 < 10.

8. The optical lens according to claim 1, characterized in that: The back focal length BFL of the optical lens and the total optical length TTL of the optical lens satisfy: 0.16 < BFL / TTL < 0.26; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.45 < BFL / f < 0.

65.

9. The optical lens according to claim 1, characterized in that: The sum ∑CT of the central thicknesses of the first lens to the seventh lens along the optical axis respectively and the sum ∑AT of the distances between any two adjacent lenses of the first lens to the seventh lens on the optical axis satisfy: 9 < ∑CT / ∑AT < 35.

10. The optical lens according to claim 1, characterized in that: The combined focal length f345 of the third lens, the fourth lens and the fifth lens and the effective focal length f of the optical lens satisfy: 0.9 <f345 / f<6.8。 11. 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 10; 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 seventh 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.

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