3D fisheye lens and camera and video camera using same

Abstract

The 3D fisheye lens sequentially comprises a first lens group G1 with positive diopter, an aperture stop and a second lens group G2 with positive diopter from an object side to an image plane side, the first lens group G1 is divided into two parts, the object side is a front part G1a with negative diopter, the image plane side is a rear part G1b with positive diopter, and the second lens group G2 is divided into two parts. Wherein the G1a of the front part is composed of three continuous negative lenses, and the G1b of the rear part is a biconvex double-sided aspheric surface. The fisheye lens provided by the invention has the advantages of miniaturization, high performance, large image field, a field angle exceeding 200 degrees, enough gentle curvature radius of the first glass, enough small mutual shielding, enough small effective aperture, and capability of simulating the visual effect of eyes.

Description

Technical Field

[0001] The present invention is a full-circle fisheye lens with a field of view of more than 190 degrees, which can be widely used in digital camera lenses, video camera lenses, drone cameras, and especially in the field of shooting 3D scenes. Background Art

[0002] At present, there are many known fisheye lenses with an angle of view exceeding 180 degrees. However, when applied to the VR field, splicing is required, and the viewing angle needs to exceed 180 degrees, preferably more than 190 degrees. In addition, when shooting 3D effects, it is necessary to imitate the visual effect of the human eye. The distance between the two fisheye lenses needs to be close to the distance between the pupils of the human eye. The distance between the pupils of the human eye is between 50-70mm, and the average value of 60-65mm is usually used as the standard. The shooting is most in line with the human eye effect. For 8k ultra-high definition, covering the full-frame (24mm×36mm) inscribed circular image field, the fisheye lens needs to be small enough, with an image field diameter close to 24mm and a field angle of The requirement must be greater than 190 degrees. At the same time, during 3D shooting, the two lenses placed side by side should not block each other as much as possible, and the curvature radius of the first lens must be sufficiently gentle. However, there is basically no fisheye lens in the prior art that meets the requirements of a field of view angle of more than 190 degrees, a sufficiently small size, a sufficiently high performance, and a sufficiently large image field. For example, the well-known Japanese Patent No. 2004-258515 has a large enough image field, but the outer diameter of the glass at the front end is too large. If two fisheye lenses are placed side by side, the diameter will be much larger than 70mm, which does not meet the distance between the human eye's binocular pupils. At the same time, the field of view angle is only 180 degrees, and the effect of application will be very unsatisfactory.

[0003] There is also the well-known Japanese Patent Application No. 2016-184136. Although the image field size is appropriate and the field of view angle exceeds 190 degrees and is close to 200 degrees, the outer diameter of the first piece of glass is too large, and the radius of curvature is too strong. If the two lenses are arranged in parallel, the optical axis distance between them will be greater than 70 mm, which exceeds the pupil distance of the human eye. At the same time, because the radius of curvature of the first piece of glass is less than 50 mm, it will be very abrupt and the mutual vision will be seriously blocked. Therefore, the effect of 3D shooting is not ideal and there are still many problems. Summary of the invention

[0004] In order to overcome the problem that the above-mentioned known fisheye lens cannot be miniaturized, have a large image field, a field of view angle exceeding 190 degrees, and the curvature radius of the first glass is sufficiently gentle, the present invention will provide a fisheye lens with miniaturization, high performance, a large image field, a field of view angle exceeding 190 degrees, and a curvature radius of the first glass being sufficiently gentle.

[0005] To achieve the above object, the technical solution of the present invention is: a 3D fisheye lens, which comprises, from the object side to the image side, a first lens group G1 with positive refractive power and a second lens group G2 with positive refractive power in sequence;

[0006] The aperture Stop is disposed between the first lens group G1 and the second lens group G2.

[0007] Furthermore, the lens satisfies the following conditions (1), (2), and (3):

[0008] 1.2≤F2 / F1≤2.0 (1)

[0009] 1.5≤F1 / FL≤2.5 (2)

[0010] 190≤2ω≤230 (3)

[0011] in,

[0012] ω: half field of view of the optical system;

[0013] FL: focal length of the entire optical system;

[0014] F1: focal length of the first lens group G1;

[0015] F2: focal length of the second lens group G2.

[0016] If the lower limit of the conditional expression 1.2≤F2 / F1≤2.0(1) is exceeded, the refractive power of the first lens group G2 is too strong, the light convergence ability at the edge becomes stronger, the exit pupil distance of the optical system is far away, and the angle of the edge exit light tends to be flat. Although the edge illumination will be very favorable, the volume of the optical system is difficult to control, the diameter of the rear lens will be large, and the length of the entire optical system will also be large. If the upper limit of the conditional expression (1) is exceeded, although the length of the optical system can be effectively controlled, the final exit pupil distance is too close, the angle of the edge light exiting to the edge is too large, and the vignetting will be very serious.

[0017] If the lower limit of the conditional expression 1.5≤F1 / FL≤2.5(2) is exceeded, the refractive power of the first lens group G1 will be very strong. Although the volume of the first lens group can be effectively controlled, various aberrations are difficult to control due to the strong refractive power, and high performance is difficult. If the upper limit of the conditional expression (2) is exceeded, the refractive power of the first lens group G1 is too weak, the light convergence ability at the edge is weakened, the volume of the entire optical system is difficult to control, and the diameter of the lens at the front end will be very large.

[0018] If the lower limit of the conditional expression 190≤2ω≤230(3) is exceeded, the field of view is not wide enough. If splicing is required, the overlap is insufficient and discontinuities are likely to occur. If the upper limit of the conditional expression (3) is exceeded, splicing is easy but the design difficulty increases too much and the edge performance is difficult to guarantee.

[0019] Furthermore, the first lens group G1 is divided into two parts, a front part G1a with negative refractive power on the object side and a rear part G1b with positive refractive power on the image side.

[0020] Furthermore, the first lens group G1 satisfies the following conditions (4), (5), and (6):

[0021] 0.3≤|F1a / F1b|≤0.6 (4)

[0022] 0.85≤D i / G1R1≤1.1 (5)

[0023] 7.0≤FL / G1R1≤10 (6)

[0024] in,

[0025] D i: effective aperture of the surface of the first lens group G1 most on the object side;

[0026] G1 R1: the radius of curvature of the surface of the first lens group G1 most on the object side;

[0027] F1a: focal length of the front portion of the first lens group G1a;

[0028] F1 b: focal length of the rear portion G1b of the first lens group G1.

[0029] If the lower limit of the conditional expression 0.3≤|F1a / F1b|≤0.6(4) is exceeded, the refractive power of the front half G1a of the first lens group G1 is too strong. Although it is easy to achieve the effective aperture D i of the lens on the most object side, the refractive power is too strong, which makes it difficult to control various aberrations and achieve high performance. If the upper limit of the conditional expression (4) is exceeded, although it is beneficial to correct aberrations, it is very difficult to design a miniaturized lens, resulting in a large volume, which is not conducive to the space requirement for placing two lenses side by side during 3D shooting.

[0030] If the lower limit of the conditional expression 0.85≤D i / G1R1≤1.1(5) is exceeded, the radius of curvature G1R1 of the lens closest to the object side is very gentle, but it is difficult to achieve a viewing angle exceeding 200 degrees. If the upper limit of the conditional expression (5) is exceeded, the radius of curvature G1R1 of the lens closest to the object side is too convex, or the effective aperture Di is too large, and the curvature of G1R1 is too strong and convex. Although the performance is easy to achieve, it will cause the two lenses to block each other during 3D shooting, or the effective aperture Di of the lens closest to the object side is too large, exceeding the pupil distance of the human eye, and the shooting result cannot achieve an effect similar to that of human eye observation.

[0031] If the lower limit of the conditional expression 7.0≤FL / G1R1≤10(6) is exceeded, the radius of curvature G1R1 of the lens surface closest to the object side is very gentle, but it is difficult to achieve a viewing angle exceeding 200 degrees. If the upper limit of the conditional expression (6) is exceeded, the radius of curvature G1R1 of the lens surface closest to the object side is too convex, and the curvature of G1R1 is too strong. Although the performance is easy to achieve, it will cause the two lenses to block each other's viewing angle, making the observation field range not wide enough.

[0032] Furthermore, the front part G1a is composed of three consecutive negative lenses.

[0033] Furthermore, the rear portion G1 b adopts a double-convex double-sided aspherical surface.

[0034] The invention also provides a camera having the 3D fisheye lens.

[0035] The invention also provides a camera having the 3D fisheye lens.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention provides a fisheye lens which is miniaturized, high-performance, has a large image field, a field of view angle of more than 200 degrees, a sufficiently gentle radius of curvature of the first glass, minimal mutual occlusion, and a sufficiently small effective aperture, and can imitate the visual effect of binocular vision of the human eye. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is an optical structure diagram of Embodiment 1 of the present invention;

[0039] Figure 2 The spherical aberration, field curvature aberration, distortion aberration and chromatic aberration of magnification at infinity of Example 1;

[0040] Figure 3 is an optical structure diagram of Embodiment 2 of the present invention;

[0041] Figure 4The spherical aberration, field curvature aberration, distortion aberration and chromatic aberration of magnification at infinity of Example 2;

[0042] Figure 5 is an optical structure diagram of Embodiment 3 of the present invention;

[0043] Figure 6 These are the spherical aberration, field curvature, distortion, and lateral chromatic aberration at infinity in Example 3. DETAILED DESCRIPTION

[0044] The present invention is further described below in conjunction with the accompanying drawings and embodiments. The present invention includes but is not limited to the following embodiments.

[0045] Example 1: Figure 1 As shown, from the object side to the image side, it includes a first lens group G1 with positive refractive power, an aperture stop and a second lens group G2 with positive refractive power. The above-mentioned first lens group G1 is divided into two parts, the object side is a front part G1a with negative refractive power, and the image side is a rear part G1b with positive refractive power, wherein the front part G1a is composed of 3 consecutive negative lenses, and the rear part G1b is a double-convex double-sided aspheric surface.

[0046] The spherical aberration, field curvature aberration, distortion aberration and chromatic aberration of magnification at infinity of Example 1 are as follows: Figure 2 shown.

[0047] The data of Example 1 are as follows.

[0048] R (mm): radius of curvature of each surface;

[0049] D (mm): the distance between lenses and the thickness of lenses;

[0050] Nd: refractive index of each glass at d line;

[0051] Vd: Abbe number of glass;

[0052] Focal length: 7.563;

[0053] FNO: 3.6;

[0054] Half-frame angle ω: 106°.

[0055] NS R D Nd ABV 1 62.0000 4.5716 1.92286 20.88 2 17.5954 8.5156 3 52.8532 2.0000 1.72916 54.67 4 17.6444 8.1577 5 -31.7071 1.5000 1.45860 90.19 6 19.2200 6.9370 7ASPH 20.7983 6.8701 1.88982 34.90 8ASPH -35.4245 9.8970 9STOP inf 1.0000 10 -35.7231 1.0000 1.80906 23.44 11 16.5801 2.3130 1.49700 81.61 12 -20.2560 1.5320 13 236.7912 2.0904 1.74523 52.47 14 -42.5360 0.1500 15 18.4235 6.4902 1.49700 81.61 16 -15.0920 1.0000 1.75702 24.91 17 -45.1668 1.0000 18 inf 2.0000 1.51680 64.20 19 inf 11.0012

[0056]

[0057]

[0058] Example 2: Figure 3As shown, from the object side to the image side, it includes a first lens group G1 with positive refractive power, an aperture stop and a second lens group G2 with positive refractive power. The above-mentioned first lens group G1 is divided into two parts, the object side is a front part G1a with negative refractive power, and the image side is a rear part G1b with positive refractive power, wherein the front part G1a is composed of 3 consecutive negative lenses, and the rear part G1b is a double-convex double-sided aspheric surface.

[0059] The spherical aberration, field curvature aberration, distortion aberration and chromatic aberration of magnification at infinity of Example 2 are as follows: Figure 4 shown.

[0060] The data of Example 2 are as follows:

[0061] R (mm): radius of curvature of each surface;

[0062] D (mm): the distance between lenses and the thickness of lenses;

[0063] Nd: refractive index of each glass at d line;

[0064] Vd: Abbe number of glass;

[0065] Focal length: 7.3643;

[0066] FNO:3.0;

[0067] Half-screen angle ω: 105°.

[0068]

[0069]

[0070]

[0071] Example 3: Figure 5 As shown, from the object side to the image side, it includes a first lens group G1 with positive refractive power, an aperture stop and a second lens group G2 with positive refractive power. The above-mentioned first lens group G1 is divided into two parts, the object side is a front part G1a with negative refractive power, and the image side is a rear part G1b with positive refractive power, wherein the front part G1a is composed of 3 consecutive negative lenses, and the rear part G1b is a double-convex double-sided aspheric surface.

[0072] The spherical aberration, field curvature aberration, distortion aberration and chromatic aberration of magnification at infinity of Example 3 are as follows: Figure 6 shown.

[0073] The data of Example 3 are as follows:

[0074] R (mm): radius of curvature of each surface;

[0075] D (mm): the distance between each lens and the thickness of the lens; Nd: the refractive index of each glass of the d line; Vd: the Abbe number of the glass;

[0076] Focal length: 7.6380;

[0077] FNO:4.0;

[0078] Half-frame angle ω: 104°.

[0079] NS R D Nd ABV 1 65.0000 3.0000 1.92286 20.88 2 19.8467 8.6105 3 55.7588 2.6097 1.72916 57.00 4 18.5035 8.7790 5 -36.9990 1.0000 1.45860 90.19 6 22.1486 8.9711 7ASPH 22.0853 6.9006 1.91082 35.25 8ASPH -44.3444 10.4419 9STOP inf 1.0000 10 -22.7771 1.0000 1.76639 24.59 11 18.2380 2.3552 1.49700 81.61 12 -18.4065 1.5055 13 -1482.1249 2.0000 1.81783 47.74 14 -33.9984 0.1500 15 18.2809 6.5731 1.49700 81.61 16 -15.2511 1.1034 1.75378 24.34 17 -49.6402 1.0000 18 inf 2.0000 1.51680 64.20 19 inf 11.0054

[0080]

[0081]

[0082] In the above embodiment, the aspherical shape is defined as:

[0083] y: radial coordinate from the optical axis.

[0084] z: The offset in the direction of the optical axis from the intersection of the aspheric surface and the optical axis. r: The radius of curvature of the reference spherical surface of the aspheric surface.

[0085] K, 4th, 6th, 8th, 10th, 12th aspheric coefficients

[0086]

[0087] Conditional summary table:

[0088]

[0089]

[0090]

[0091] The 3D fisheye lens provided by any of the above embodiments can be applied to cameras and camcorders.

[0092] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. 3D fisheye lens, characterized in that: The lens group includes a first lens group G1 with positive refractive power and a second lens group G2 with positive refractive power in order from the object side to the image side. The aperture Stop is disposed between the first lens group G1 and the second lens group G2.

2. The 3D fisheye lens according to claim 1, characterized in that: The lens satisfies the following conditions (1), (2), and (3): 1.2≤F2 / F1≤2.0 (1) 1.5≤F1 / FL≤2.5 (2) 190≤2ω≤230 (3) in, ω: half field of view of the optical system; FL: focal length of the entire optical system; F1: focal length of the first lens group G1; F2: focal length of the second lens group G2.

3. The 3D fisheye lens according to claim 1, characterized in that: The first lens group G1 is divided into two parts: a front part G1 a with negative refractive power on the object side and a rear part G1 b with positive refractive power on the image side.

4. The 3D fisheye lens according to claim 3, characterized in that: The first lens group G1 satisfies the following conditions (4), (5), and (6): 0.3≤|F1 a / F1 b|≤0.6 (4) 0.85≤Di / G1 R1≤1.1 (5) 7.0≤FL / G1 R1≤10 (6) in, Di: the effective aperture of the surface of the first lens group G1 most on the object side; G1 R1: the radius of curvature of the surface of the first lens group G1 most on the object side; F1 a: focal length of the front portion of the first lens group G1 a; F1 b: focal length of the rear portion of the first lens group G1 b.

5. The 3D fisheye lens according to claim 3, characterized in that: The front part G1a is composed of three consecutive negative lenses.

6. The 3D fisheye lens according to claim 3, characterized in that: The rear portion G1 b adopts a double convex double-sided aspherical surface.

7. A camera having the 3D fisheye lens according to any one of claims 1 to 6.

8. A camera having the 3D fisheye lens according to any one of claims 1 to 6.

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