Optical lens

Abstract

The application discloses an optical lens, which comprises, along an optical axis from an object side to an imaging surface, a first lens with positive focal power, the image side of which is a convex surface; a second lens with positive focal power, the image side of which is a convex surface; a third lens with positive focal power, the object side of which is a convex surface; a fourth lens with focal power, the image side of which is a convex surface; a fifth lens with negative focal power, the image side of which is a convex surface; a sixth lens with positive focal power, the image side of which is a convex surface; a seventh lens with negative focal power, the image side of which is a convex surface; and an eighth lens with positive focal power, the object side of which is a convex surface. The optical lens has the advantages of good imaging quality, a large field of view, a large aperture and a small window.

Description

Technical Field

[0001] This invention relates to the field of imaging lens technology, and in particular to an optical lens. Background Technology

[0002] In recent years, with the commercial promotion of 5G, the VR / AR industry has been developing at an accelerated pace, and it has been widely used in many fields such as gaming, social networking, education, and healthcare.

[0003] With the development of Virtual Reality (VR) technology, VR devices are becoming increasingly diverse in form and type, and their applications are expanding. Meanwhile, the vast user base is demanding higher and higher levels of sensory experience from VR users. Many existing social VR applications appear to support realistic eye movements, including blinking, saccades, and object focusing, but all of this is achieved through animation and programming logic. This illusion helps reduce the robotic feel of virtual characters, but when you actually interact with someone face-to-face, the actual nonverbal information is lost. Eye tracking—capable of quickly and accurately detecting the user's gaze direction within a VR headset and rapidly and accurately monitoring eye movements—provides a wealth of eye movement data. Because eye movements are closely related to cognition and can be used to study human cognitive processes, eye tracking is considered a potential new input method. Applied to VR, it can provide users with a more realistic experience and enable new interaction methods. Currently, it is a technology that many manufacturers are actively researching and using. Summary of the Invention

[0004] Therefore, the purpose of this invention is to provide an optical lens that has at least the advantages of good image quality, large field of view, large aperture and small window.

[0005] This invention provides an optical lens comprising, along the optical axis from the object side to the imaging plane, the following components in sequence: a first lens with positive optical power, the image side of which is convex; a second lens with positive optical power, the image side of which is convex; a third lens with positive optical power, the object side of which is convex; a fourth lens with optical power, the image side of which is convex; a fifth lens with negative optical power, the image side of which is convex; a sixth lens with positive optical power, the image side of which is convex; a seventh lens with negative optical power, the image side of which is convex; and an eighth lens with positive optical power, the object side of which is convex.

[0006] Compared to existing technologies, the optical lens provided by this invention employs eight lenses with specific optical powers. By rationally allocating the thickness and optical power of each lens and rationally controlling the surface shape of each lens, the optical lens possesses advantages such as excellent image quality, a large field of view, a large aperture, and a small window. When applied to VR devices, it can be used for eye tracking and can obtain clearer eye images, improving the accuracy of eye tracking and bringing users an excellent sensory experience. At the same time, by rationally allocating the spacing between each lens, the total optical length of the optical lens can reach 90mm to 120mm, which can better meet the customer's need for the image plane to be farther away from the human eye. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of the structure of the optical lens according to the first embodiment of the present invention.

[0008] Figure 2 This is a distortion curve diagram of the optical lens according to the first embodiment of the present invention.

[0009] Figure 3 This is a chromatic aberration curve of the optical lens according to the first embodiment of the present invention.

[0010] Figure 4 This is a schematic diagram of the structure of the optical lens according to the second embodiment of the present invention.

[0011] Figure 5 This is a distortion curve diagram of the optical lens according to the second embodiment of the present invention.

[0012] Figure 6 This is a chromatic aberration curve of the optical lens according to the second embodiment of the present invention.

[0013] Figure 7 This is a schematic diagram of the structure of the optical lens according to the third embodiment of the present invention.

[0014] Figure 8 This is a distortion curve diagram of the optical lens according to the third embodiment of the present invention.

[0015] Figure 9 This is a chromatic aberration curve of the optical lens according to the third embodiment of the present invention. Detailed Implementation

[0016] To make the objectives, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present invention will be thorough and complete.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Throughout this specification, the same reference numerals refer to the same elements.

[0018] The present invention proposes an optical lens, which comprises, in sequence along the optical axis from the object side to the imaging plane: an aperture stop, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a filter.

[0019] The first lens has positive optical power, its object-side surface is concave, and its image-side surface is convex; the second lens has positive optical power, its object-side surface is concave, and its image-side surface is convex; the third lens has positive optical power, its object-side surface is convex, and its image-side surface is concave; the fourth lens has either positive or negative optical power, its object-side surface is concave, and its image-side surface is convex; the fifth lens has negative optical power, its object-side surface is concave, and its image-side surface is convex; the sixth lens has positive optical power, its object-side surface is either convex or concave, and its image-side surface is convex; the seventh lens has negative optical power, its object-side surface is concave, and its image-side surface is convex; and the eighth lens has positive optical power, its object-side surface is convex, and its image-side surface is convex.

[0020] In some embodiments, the optical lens satisfies the following condition:

[0021] 50 < FOV / FNO < 80; (1)

[0022] Wherein, FOV represents the maximum field of view of the optical lens, and FNO represents the aperture number of the optical lens. Satisfying the above condition (1) can achieve a balance between a large field of view and a large aperture, increase the amount of light transmitted, make the overall illumination uniform, and improve the imaging quality of the optical lens.

[0023] In some embodiments, the optical lens satisfies the following condition:

[0024] 0.007<D11 / TTL<0.018; (2)

[0025] Where D11 represents the effective aperture of the first lens side surface, and TTL represents the total optical length of the optical lens. Satisfying the above condition (2) allows for a smaller window opening in the optical lens, reducing the head volume of the optical lens and facilitating the miniaturization of the optical lens.

[0026] In some embodiments, the optical lens satisfies the following condition:

[0027] -18 < f1 / f < -10; (3)

[0028] Where f1 represents the effective focal length of the first lens, and f represents the effective focal length of the optical lens. Satisfying the above condition (3) is beneficial for converging incident light rays, controlling the light path, and expanding the field of view of the optical lens.

[0029] In some embodiments, the optical lens satisfies the following condition:

[0030] -95 < TTL / f < -70; (4)

[0031] Where TTL represents the total optical length of the optical lens, and f represents the effective focal length of the optical lens. Satisfying the above condition (4) can better meet the customer's need for the imaging surface of the optical lens to be farther away from the human eye.

[0032] In some embodiments, the optical lens satisfies the following condition:

[0033] -15 < f34 / f < -10; (5)

[0034] Where f34 represents the combined focal length of the third lens and the fourth lens, and f represents the effective focal length of the optical lens. Satisfying the above condition (5) can effectively increase the degree of light refraction, giving the optical lens a larger field of view.

[0035] In some embodiments, the optical lens satisfies the following condition:

[0036] Vd4-Vd3>25; (6)

[0037] Wherein, Vd4 represents the Abbe number of the fourth lens, and Vd3 represents the Abbe number of the third lens. Satisfying the above condition (6), by selecting a combination of high and low dispersion coefficients between two adjacent lenses, it is beneficial to correct chromatic aberration, improve the image quality of the optical lens, and avoid purple fringing at the edge of the field of view.

[0038] In some embodiments, the optical lens satisfies the following condition:

[0039] 0.3 < R31 / R32 < 0.5; (7)

[0040] 0.7 < R41 / R42 < 0.9; (8)

[0041] Wherein, R31 represents the radius of curvature of the object-side surface of the third lens, R32 represents the radius of curvature of the image-side surface of the third lens, R41 represents the radius of curvature of the object-side surface of the fourth lens, and R42 represents the radius of curvature of the image-side surface of the fourth lens. Satisfying the above conditions (7) and (8) is beneficial for correcting the distortion of the optical lens, ensuring that the imaging result is not distorted, and improving the image quality of the optical lens.

[0042] In some embodiments, the optical lens satisfies the following condition:

[0043] 2.5 < CT45 / D51 < 5.0; (9)

[0044] Wherein, CT45 represents the distance on the optical axis between the fourth lens and the fifth lens, and D51 represents the effective aperture of the object side of the fifth lens. Satisfying the above condition (9) is beneficial to increasing the total optical length of the optical lens and meeting the customer's need for the imaging surface of the human eye to be far away from the optical lens.

[0045] In some embodiments, the optical lens satisfies the following condition:

[0046] -15 < f3 / f < -10; (10)

[0047] Where f3 represents the effective focal length of the third lens, and f represents the effective focal length of the optical lens. Satisfying the above condition (10) enables the optical lens to have a larger field of view, while the distortion of the optical lens can be better corrected, thereby improving the overall imaging effect of the optical lens.

[0048] In some embodiments, the optical lens satisfies the following condition:

[0049] 1.0 < f2 / f3 < 1.5; (11)

[0050] Where f2 represents the effective focal length of the second lens, and f3 represents the effective focal length of the third lens. Satisfying the above condition (11) is beneficial for correcting aberrations in the optical lens and improving the imaging quality of the optical lens.

[0051] In some embodiments, the optical lens satisfies the following condition:

[0052] -0.4<SAG22 / SAG31<-0.1; (12)

[0053] Wherein, SAG22 represents the sagitta of the image-side surface of the second lens, and SAG31 represents the sagitta of the object-side surface of the third lens. Satisfying the above condition (12) is beneficial for converging the light rays entering the optical system, correcting spherical aberration and coma in each field of view, and improving the resolving power of the optical lens.

[0054] In some embodiments, the optical lens satisfies the following condition:

[0055] 30 < f7 / f < 80; (13)

[0056] -15 < f8 / f < -10; (14)

[0057] Where f7 represents the effective focal length of the seventh lens, f8 represents the effective focal length of the eighth lens, and f represents the effective focal length of the optical lens. Satisfying the above conditions (13) and (14) is beneficial for controlling aberrations, reducing tolerance sensitivity, and improving the image quality of the optical lens.

[0058] In some embodiments, the optical lens satisfies the following condition:

[0059] 0.4 < f12 / f34 < 0.7; (15)

[0060] Where f12 represents the combined focal length of the first lens and the second lens, and f34 represents the combined focal length of the third lens and the fourth lens. Satisfying the above condition (15) is beneficial for controlling the overall length of the optical lens and better meeting customer needs.

[0061] In some embodiments, the optical lens satisfies the following condition:

[0062] -5.0 < f5 / f8 < -2.0; (16)

[0063] Where f5 represents the effective focal length of the fifth lens and f8 represents the effective focal length of the eighth lens. Satisfying the above condition (16) can slow down the turning trend of light, which is beneficial to reducing the difficulty of correcting optical lens distortion and advanced aberrations, and improving the imaging quality of the optical lens.

[0064] In this application, in order to reduce the manufacturing difficulty of the optical lens, an eight-spherical glass lens combination is adopted. By reasonably allocating the optical power of each lens, the optical lens has at least the advantages of good image quality, large field of view, large aperture and small window, which can be used to be mounted on VR devices to be used for eye tracking and to obtain clear eye images, bringing users an excellent sensory experience.

[0065] The present invention will be further described below with reference to several 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 tables of each embodiment. The following embodiments are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention.

[0066] First Embodiment

[0067] Please see Figure 1 The diagram shown is a schematic diagram of the structure of the optical lens 100 provided in the first embodiment of the present invention. The optical lens 100 includes, along the optical axis from the object side to the imaging plane, the following components in sequence: aperture ST, first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, sixth lens L6, seventh lens L7, eighth lens L8, and filter G1.

[0068] Specifically, the first lens L1 has positive optical power, its object-side surface S1 is concave, and its image-side surface S2 is convex; the second lens L2 has positive optical power, its object-side surface S3 is concave, and its image-side surface S4 is convex; the third lens L3 has positive optical power, its object-side surface S5 is convex, and its image-side surface S6 is concave; the fourth lens L4 has negative optical power, its object-side surface S7 is concave, and its image-side surface S8 is convex; the fifth lens L5 has negative optical power, its object-side surface S7 is concave, and its image-side surface S8 is convex; S9 is concave, and the image-side surface S10 of the fifth lens is convex; the sixth lens L6 has positive optical power, the object-side surface S11 of the sixth lens is concave, and the image-side surface S12 of the sixth lens is convex; the seventh lens L7 has negative optical power, the object-side surface S13 of the seventh lens is concave, and the image-side surface S14 of the seventh lens is convex; the eighth lens L8 has positive optical power, the object-side surface S15 of the eighth lens is convex, and the image-side surface S16 of the eighth lens is concave; the object-side surface of filter G1 is S17, and the image-side surface is S18; the imaging surface is adjacent to the image-side surface S18 of filter G1. Among these, 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 glass spherical lenses.

[0069] Specifically, the design parameters of the optical lens 100 provided in this embodiment are shown in Table 1.

[0070] Table 1

[0071]

[0072]

[0073] Please refer to Figure 2 and Figure 3 The figures shown are the distortion curve and chromatic aberration curve of the optical lens 100, respectively. Figure 2 As can be seen, the distortion is controlled within ±5.0mm, indicating that the distortion correction of the optical lens 100 is good; from Figure 3 As can be seen, the chromatic aberration is controlled within ±3.0%, indicating that the chromatic aberration of the optical lens 100 is well corrected. From Figure 2 , Figure 3 It can be seen that the aberrations of the optical lens 100 are well balanced, resulting in good image quality.

[0074] Second Embodiment

[0075] Please see Figure 4 The figure shows a schematic diagram of the structure of the optical lens 200 provided in the second embodiment of the present invention. The optical lens 200 in this embodiment is roughly the same as that in the first embodiment above. The main differences are: the fourth lens L4 has positive optical power, the object side surface S11 of the sixth lens L6 is convex, and the curvature radius and thickness of each lens are different.

[0076] Specifically, the design parameters of the optical lens 200 provided in this embodiment are shown in Table 2.

[0077] Table 2

[0078]

[0079] Please refer to Figure 5 and Figure 6 The figures shown are the distortion curve and chromatic aberration curve of the optical lens 200, respectively. Figure 5 As can be seen, the distortion is controlled within ±5.0mm, indicating that the distortion correction of the optical lens 200 is good; from Figure 6 As can be seen, the chromatic aberration is controlled within ±6%, indicating that the chromatic aberration of the optical lens 200 is well corrected. From Figure 5 , Figure 6 It can be seen that the aberrations of the optical lens 200 are well balanced, resulting in good image quality.

[0080] Third Embodiment

[0081] Please see Figure 7 The figure shows a schematic diagram of the structure of the optical lens 300 provided in the third embodiment of the present invention. The optical lens 300 in this embodiment is roughly the same as that in the first embodiment above. The main difference is that the fourth lens L4 has positive optical power, and the curvature radius and thickness of each lens are different.

[0082] Specifically, the design parameters of the optical lens 300 provided in this embodiment are shown in Table 3.

[0083] Table 3

[0084]

[0085] Please refer to Figure 8 and Figure 9 The figures shown are the distortion curve and chromatic aberration curve of optical lens 300, respectively. Figure 8 As can be seen, the distortion is controlled within ±4.0mm, indicating that the distortion correction of the 300mm optical lens is good; from Figure 9 This shows that the chromatic aberration is controlled within ±5%, indicating that the chromatic aberration of the 300mm optical lens is well corrected. From... Figure 8 and Figure 9 It can be seen that the aberrations of the 300mm optical lens are well balanced, resulting in good image quality.

[0086] Please refer to Table 4, which shows the optical characteristics of the optical lenses provided in the three embodiments above, including the maximum field of view (FOV), total optical length (TTL), half-image height (IH), effective focal length (f), and the relevant values ​​corresponding to each of the aforementioned conditional expressions.

[0087] Table 4

[0088] Example First Embodiment Second Embodiment Third Embodiment f(mm) -1.217 -1.285 -1.127 FNO 1.500 1.200 1.200 TTL(mm) 110.010 94.101 91.915 FOV (°) 90.000 84.000 92.000 IH(mm) 1.200 1.200 1.200 FOV / FNO 60.000 70.000 76.667 D11 / TTL 0.009 0.016 0.016 f1 / f -10.970 -15.021 -17.341 TTL / f -90.405 -73.237 -81.555 f34 / f -14.537 -11.111 -13.956 Vd4-Vd3 31.643 31.643 31.643 R31 / R32 0.464 0.368 0.387 R41 / R42 0.745 0.812 0.820 CT45 / D51 4.752 2.704 3.184 f3 / f -13.823 -11.304 -14.118 f2 / f3 1.213 1.313 1.182 SAG22 / SAG31 -0.209 -0.215 -0.261 f7 / f 33.579 31.361 77.623 f8 / f -12.901 -10.343 -11.400 f12 / f34 0.462 0.679 0.616 f5 / f8 -2.629 -2.714 -3.672

[0089] As can be seen from the distortion curves and chromatic aberration curves of the above embodiments, the distortion value of the optical lens in each embodiment is controlled within ±5.0mm and the chromatic aberration is controlled within ±6%, indicating that the optical lens provided by the present invention has good imaging quality.

[0090] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. An optical lens comprising eight lenses with optical power, characterized in that, Along the optical axis from the object side to the imaging plane, the following are included in sequence: A first lens having positive optical power, wherein the image-side surface of the first lens is convex; A second lens with positive optical power, wherein the image-side surface of the second lens is convex; A third lens with positive optical power, wherein the object side of the third lens is convex; A fourth lens with optical power, wherein the image-side surface of the fourth lens is convex; A fifth lens with negative optical power, wherein the image-side surface of the fifth lens is convex; A sixth lens with positive optical power, wherein the image-side surface of the sixth lens is convex; A seventh lens with negative optical power, wherein the image-side surface of the seventh lens is convex; An eighth lens having positive optical power, wherein the object side of the eighth lens is convex; The optical lens satisfies the following condition: -95 < TTL / f < -70; Wherein, TTL represents the total optical length of the optical lens, and f represents the effective focal length of the optical lens.

2. The optical lens according to claim 1, characterized in that, The optical lens satisfies the following condition: 50° < FOV / FNO < 80°; Wherein, FOV represents the maximum field of view of the optical lens, and FNO represents the aperture number of the optical lens.

3. The optical lens according to claim 1, characterized in that, The optical lens satisfies the following condition: 0.007 < D11 / TTL < 0.018; Wherein, D11 represents the effective aperture of the side of the first lens, and TTL represents the total optical length of the optical lens.

4. The optical lens according to claim 1, characterized in that, The optical lens satisfies the following condition: -18 < f1 / f < -10; Where f1 represents the effective focal length of the first lens, and f represents the effective focal length of the optical lens.

5. The optical lens according to claim 1, characterized in that, The optical lens satisfies the following condition: -90.405≤TTL / f≤-73.237; Where TTL represents the total optical length of the optical lens, and f represents the effective focal length of the optical lens; The optical lens also satisfies: The object-side surface of the first lens is concave. The object-side surface of the second lens is concave. The image-side surface of the third lens is concave. The object-side surface of the fourth lens is concave. The object-side surface of the fifth lens is concave. The object-side surface of the seventh lens is concave. The image-side surface of the eighth lens is convex.

6. The optical lens according to claim 1, characterized in that, The optical lens satisfies the following condition: -15 < f34 / f < -10; Wherein, f34 represents the combined focal length of the third lens and the fourth lens, and f represents the effective focal length of the optical lens.

7. The optical lens according to claim 1, characterized in that, The optical lens satisfies the following condition: 2.5 < CT45 / D51 < 5.0; Wherein, CT45 represents the distance on the optical axis between the fourth lens and the fifth lens, and D51 represents the effective aperture of the object side of the fifth lens.

8. The optical lens according to claim 1, characterized in that, The optical lens satisfies the following condition: -15 < f3 / f < -10; Where f3 represents the effective focal length of the third lens, and f represents the effective focal length of the optical lens.

9. The optical lens according to claim 1, characterized in that, The optical lens satisfies the following condition: 1.0 < f2 / f3 < 1.5; Where f2 represents the effective focal length of the second lens and f3 represents the effective focal length of the third lens.

10. The optical lens according to claim 1, characterized in that, The optical lens satisfies the following condition: 30 < f7 / f < 80; -15 < f8 / f < -10; Wherein, f7 represents the effective focal length of the seventh lens, f8 represents the effective focal length of the eighth lens, and f represents the effective focal length of the optical lens.

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