Low-distortion optical lens with large field of view from ultraviolet to visible

Abstract

The invention discloses an ultraviolet-to-visible large-view-field low-distortion optical lens, and belongs to the technical field of imaging lenses. Comprising a front lens group, an aperture diaphragm, a seventh lens, a balsaming lens group and a rear lens which are sequentially arranged at intervals from the object side to the imaging side along the optical axis, and the balsaming lens group comprises a first balsaming biconvex positive lens, a balsaming biconcave negative lens and a second balsaming biconvex positive lens which are sequentially arranged from the object side to the imaging side along the optical axis in an attached mode. The object side surface and the image side surface of the first cemented biconvex positive lens are convex surfaces, the object side surface and the image side surface of the cemented biconcave negative lens are concave surfaces, and the object side surface and the image side surface of the second cemented biconvex positive lens are convex surfaces. By reasonably distributing the focal power of the front lens group, the seventh lens, the balsaming lens group and the rear lens, the ultraviolet-to-near infrared large-view-field low-distortion imaging lens which is large in view field angle, low in distortion, telecentric in image space and good in imaging quality is formed, and the imaging lens is particularly suitable for the multispectral large-view-field imaging fields such as spectrometers and polarization cameras.

Description

Technical Field

[0001] The present invention relates to the technical field of imaging lenses, and in particular to an ultraviolet to visible large field of view low distortion optical lens. Background Art

[0002] In recent years, with the rapid development of remote sensing detection technology, the demand for large field of view, wide bandwidth, and multi-band detection has become increasingly urgent, which has also put forward higher requirements for the matching imaging lenses.

[0003] In order to meet the actual application requirements, imaging lenses are usually required to have large field of view, wide spectral range, long back intercept, low distortion, compact structure, etc. Due to the sharp increase in aberrations caused by the increase in field of view, it is very difficult to correct distortion, and aspheric surfaces are usually introduced at a position far away from the field stop to balance distortion and astigmatism.

[0004] For example, a Chinese patent application number CN112817119A discloses an optical lens for aerospace use, including the first lens to the tenth lens arranged in sequence from the object side to the image side, all lenses adopt a separate structure, wherein the first lens and the tenth lens adopt glass aspheric surface, and have the characteristics of large field of view, image side telecentricity, and good imaging quality, but the edge field of view distortion is about 40%, and the distortion value is large, which greatly increases the difficulty of geometric calibration and correction. The Xi'an Institute of Optics and Precision Mechanics of the Chinese Academy of Sciences proposed a large field of view low distortion lens, including an anti-telephoto group, a double Gaussian lens group and an output lens group coaxially arranged in sequence along the incident direction of the light, a total of 3 aspheric surfaces and 2 cemented lens groups are used, the maximum distortion is less than 4.7%, the size is ≤Φ28×56mm, the volume is small, and good imaging quality can be achieved under the temperature conditions of -40℃-60℃, but the lens does not have the characteristics of image side telecentricity, resulting in a significant decrease in edge illumination, and the maximum field of view is only 115°, which still needs to be improved.

[0005] Existing large-field-of-view imaging lenses have technical problems such as large distortion and low edge illumination, and are not suitable for multi-spectral large-field-of-view imaging fields such as spectrometers and polarization cameras. Summary of the invention

[0006] In order to solve the technical problems of large distortion and low edge illumination in existing large field of view imaging lenses, the purpose of the present invention is to provide an ultraviolet to near-infrared large field of view low distortion imaging lens with large field of view angle, low distortion, image space telecentricity and good imaging quality, which is particularly suitable for multi-spectral large field of view imaging fields such as spectrometers and polarization cameras.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] An ultraviolet to visible large field low distortion optical lens, comprising a front lens group, an aperture stop, a seventh lens, a cemented lens group and a rear lens arranged in sequence from the object side to the imaging side along the optical axis, the cemented lens group comprising a No. 1 cemented biconvex positive lens, a cemented biconcave negative lens and a No. 2 cemented biconvex positive lens which are bonded in sequence from the object side to the imaging side along the optical axis, the object side surface and the image side surface of the No. 1 cemented biconvex positive lens are both convex surfaces, the object side surface and the image side surface of the cemented biconcave negative lens are both concave surfaces, the object side surface and the image side surface of the No. 2 cemented biconvex positive lens are both convex surfaces, wherein the image side surface of the No. 1 cemented biconvex positive lens is bonded to the object side surface of the cemented biconcave negative lens, the image side surface of the cemented biconcave negative lens is bonded to the object side surface of the No. 2 cemented biconvex positive lens, and the optical power of the cemented lens group satisfies: 0.04≤absolute value of optical power≤0.08.

[0009] As a further solution of the present invention: the refractive index range of the No. 1 glued biconvex positive lens is 1.40≤n≤1.45, and the dispersion range is 80≤ν≤95; the refractive index range of the glued biconcave negative lens is 1.85≤n≤1.90, and the dispersion range is 30≤ν≤45; the refractive index range of the No. 2 glued biconvex positive lens is 1.40≤n≤1.45, and the dispersion range is 80≤ν≤95.

[0010] As a further solution of the present invention: the front lens group includes:

[0011] A first lens having negative optical power, whose object side surface is convex, image side surface is concave, 0.005≤optical power absolute value≤0.01, and the first lens has a clear aperture of less than 120 mm;

[0012] The second lens with negative optical power has a convex object side surface and a concave image side surface, and the absolute value of the optical power is 0.01≤≤0.03;

[0013] The third lens with negative optical power has a flat object side surface and a concave image side surface, and the absolute value of the optical power is 0.01≤≤0.02;

[0014] The fourth lens element has negative power, both the object side surface and the image side surface are concave, and the absolute value of the power is 0.02≤≤0.04;

[0015] A fifth lens having positive refractive power, whose object side surface is concave, whose image side surface is convex, and whose absolute value of refractive power is 0.01≤≤0.02;

[0016] The sixth lens element has positive refractive power, both the object side surface and the image side surface are convex, and the absolute value of the refractive power is 0.01≤≤0.02;

[0017] The first lens to the sixth lens are sequentially arranged from the object side to the imaging side along the optical axis.

[0018] As a further solution of the present invention: the refractive index range of the first lens is 1.40≤n≤1.55, and the dispersion range is 70≤ν≤90; the refractive index range of the second lens is 1.60≤n≤1.70, and the dispersion range is 55≤ν≤65; the refractive index range of the third lens is 1.60≤n≤1.70, and the dispersion range is 55≤ν≤65; the refractive index range of the fourth lens is 1.65≤n≤1.80, and the dispersion range is 25≤ν≤40; the refractive index range of the fifth lens is 1.60≤n≤1.70, and the dispersion range is 40≤ν≤45; the refractive index range of the sixth lens is 1.60≤n≤1.70, and the dispersion range is 40≤ν≤45.

[0019] As a further solution of the present invention: the image side surface of the second lens and the image side surface of the rear lens are both aspherical surfaces.

[0020] As a further solution of the present invention: the aspheric surface shapes of the second lens and the rear lens satisfy the equation:

[0021]

[0022] Among them, z is the aspheric surface sag, c is the aspheric surface vertex curvature, y is the aperture, k is the cone coefficient, A4 is the 4th aspheric surface coefficient, A6 is the 6th aspheric surface coefficient, A8 is the 8th aspheric surface coefficient, A 10 is the 10th-order aspheric coefficient.

[0023] As a further solution of the present invention: the seventh lens is a positive meniscus lens with positive optical power, 0.01≤absolute value of optical power≤0.04, the refractive index range of the seventh lens is 1.65≤n≤1.80, and the dispersion range is 25≤ν≤40.

[0024] As a further solution of the present invention: the rear lens is a double convex lens with negative optical power, and its object side and image side are both convex, 0.05≤optical power absolute value≤0.08, the refractive index range of the rear lens is 1.60≤n≤1.70, and the dispersion range is 55≤ν≤65.

[0025] As a further solution of the present invention: the effective focal length f of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 4≤f / EPD; the back focus BFL of the optical lens and the total optical length TTL of the optical lens satisfy: 0.08≤BFL / TTL≤0.15; the relative distortion DI ST of the optical lens satisfies: DI ST≤2.5%.

[0026] As a further solution of the present invention: the incident angle CRA of all the chief rays of the field of view on the image plane satisfies: CRA≤3°.

[0027] Beneficial effects of the present invention:

[0028] (1) The present invention provides an ultraviolet to visible wide field low distortion optical lens, comprising a front lens group, an aperture stop, a seventh lens, a cemented lens group and a rear lens arranged in sequence along the optical axis from the object side to the imaging side. By reasonably allocating the optical power of the front lens group, the seventh lens, the cemented lens group and the rear lens, an ultraviolet to near-infrared wide field low distortion imaging lens with a large field of view angle, low distortion, image telecentricity and good imaging quality is formed. The lens is particularly suitable for multi-spectral wide field imaging fields such as spectrometers and polarization cameras.

[0029] (2) In the present invention, both the second lens and the rear lens adopt a single-sided aspheric surface, which reduces the pressure of single-piece aspheric surface correction distortion and astigmatism aberration, and solves the problem of difficulty in aspheric surface processing caused by the large sag height of the traditional single-piece aspheric surface. The aspheric surface in the present invention meets the current aspheric surface processing technology and has strong engineering feasibility;

[0030] (3) The present invention solves the chromatic aberration problem caused by the wide-band optical system by using low-refractive index and low-dispersion materials, and the maximum lateral chromatic aberration is less than 15um. In addition, by constraining the incident angle of the main light of the edge field of view, the image telecentricity is achieved, and the illumination uniformity of the edge field of view is improved. The back intercept of the optical lens of the present invention is greater than 25mm, which reserves sufficient space for the installation of the detector;

[0031] (4) In the present invention, the focal length of the laminated lens is reasonably distributed so that the incident angle of the main light on each surface of the laminated lens is no more than 35°, and the aberration correction capability borne by each surface of the laminated lens is relatively balanced, thereby reducing the tolerance sensitivity of processing and assembly, and improving the yield of the imaging lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described below in conjunction with the accompanying drawings.

[0033] Figure 1 This is a schematic diagram of the structure of an ultraviolet to visible large field of view low distortion optical lens of the present invention;

[0034] Figure 2 It is a schematic diagram of the structure of the front lens group of the present invention;

[0035] Figure 3 It is a schematic diagram of the structure of the aperture stop, the seventh lens, the cemented lens group and the rear lens of the present invention;

[0036] Figure 4 It is a modulation transfer function (MTF) curve of an ultraviolet to visible large field of view low distortion optical lens of the present invention;

[0037] Figure 5It is a relative distortion curve of an ultraviolet to visible large field low distortion optical lens of the present invention;

[0038] Figure 6 It is a lateral chromatic aberration curve of an ultraviolet to visible large field low distortion optical lens of the present invention.

[0039] In the figure: 1, front lens group; 11, first lens; 12, second lens; 13, third lens; 14, fourth lens; 15, fifth lens; 16, sixth lens; 2, aperture stop; 3, seventh lens; 4, cemented lens group; 41, cemented biconvex positive lens No. 1; 42, cemented biconcave negative lens; 43, cemented biconvex positive lens No. 2; 5, rear lens. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] See also Figure 1 As shown, an embodiment of the present invention provides an ultraviolet to visible large field of view low distortion optical lens, including a front lens group 1, an aperture stop 2, a seventh lens 3, a cemented lens group 4 and a rear lens 5 arranged in sequence along the optical axis from the object side to the imaging side.

[0042] Specifically, see Figure 2 As shown, in this embodiment, the front lens group 1 includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15 and a sixth lens 16 which are sequentially arranged along the optical axis from the object side to the imaging side.

[0043] The first lens 11 is a meniscus lens with negative optical power, with a convex object side and a concave image side, 0.005≤absolute optical power≤0.01, and the aperture of the first lens 11 is less than 120 mm. In this embodiment, the absolute optical power of the first lens 1111 is preferably 0.0075, and may also be an optical power value within other optical power ranges. The refractive index range of the first lens 11 is 1.40≤n≤1.50, and the dispersion range is 70≤ν≤90. In this embodiment, the first lens 11 is preferably made of N-PK51 glass material, with a refractive index of 1.53 and a dispersion of 76.98, and may also be a glass material within other refractive index ranges and dispersion ranges.

[0044] The second lens 12 is a meniscus lens with negative optical power, with a convex object side and a concave image side, and the absolute value of the optical power is 0.01≤≤0.03. In this embodiment, the absolute value of the optical power of the second lens 12 is preferably 0.023, and it can also be an optical power value within other optical power ranges. The refractive index range of the second lens 1212 is 1.60≤n≤1.70, and the dispersion range is 50≤ν≤65. In this embodiment, the second lens 12 is preferably made of N-SK14 glass material, with a refractive index of 1.60 and a dispersion of 60.60, and it can also be a glass material within other refractive index ranges and dispersion ranges.

[0045] The third lens 13 is a plano-concave lens with negative optical power, whose object side surface is a plane and image side surface is a concave surface, 0.01≤absolute value of optical power≤0.03, and the third lens 13 of this embodiment preferably has an absolute value of optical power of 0.016, and may also have an optical power value within other optical power ranges. The refractive index range of the third lens 13 is 1.60≤n≤1.70, and the dispersion range is 50≤ν≤65. The third lens of this embodiment is preferably a 13N-SK14 model glass material, whose refractive index is 1.60 and dispersion is 60.60, and may also be a glass material within other refractive index ranges and dispersion ranges.

[0046] The fourth lens 14 is a double concave lens with negative optical power, and its object side surface and image side surface are both concave, 0.02≤optical power absolute value≤0.04, and the fourth lens 14 of this embodiment preferably has an optical power absolute value of 0.022, and can also be an optical power value within other optical power ranges. The refractive index range of the fourth lens 14 is 1.65≤n≤1.80, and the dispersion range is 25≤ν≤40. The fourth lens 14 of this embodiment is preferably a glass material of model N-SF15, with a refractive index of 1.70 and a dispersion of 30.20, and can also be a glass material within other refractive index ranges and dispersion ranges.

[0047] The fifth lens 15 is a meniscus lens with positive power, whose object side surface is concave and image side surface is convex, 0.01≤absolute value of power≤0.02, and the fifth lens 15 of this embodiment preferably has an absolute value of power of 0.011, and may also have a power value within other power ranges. The refractive index range of the fifth lens 15 is 1.60≤n≤1.70, and the dispersion range is 40≤ν≤45. The fifth lens 15 of this embodiment preferably has a glass material of model N-KZFS4, whose refractive index is 1.61 and dispersion is 44.49, and may also be a glass material within other refractive index ranges and dispersion ranges.

[0048] The sixth lens 16 is a biconvex lens with positive power, and its object side surface and image side surface are both convex, 0.01≤absolute value of power≤0.02, and the sixth lens 16 in this embodiment preferably has an absolute value of power of 0.011, and may also have a power value within other power ranges. The refractive index range of the sixth lens 16 is 1.60≤n≤1.70, and the dispersion range is 40≤ν≤45. The sixth lens 16 in this embodiment preferably has a glass material of model N-KZFS4, whose refractive index is 1.61 and dispersion is 44.49, and may also be a glass material within other refractive index ranges and dispersion ranges.

[0049] Specifically, in this embodiment, the seventh lens 3 is a positive meniscus lens with positive optical power, whose object side surface is concave and image side surface is convex, 0.01≤absolute value of optical power≤0.04, and the absolute value of optical power of the seventh lens 3 in this embodiment is preferably 0.014, and may also be an optical power value within other optical power ranges. The refractive index range of the seventh lens 3 is 1.65≤n≤1.80, and the dispersion range is 25≤ν≤40. The seventh lens 3 in this embodiment is preferably a glass material of model N-SF15, whose refractive index is 1.70, dispersion is 30.20, and dispersion is 44.49, and may also be a glass material within other refractive index ranges and dispersion ranges.

[0050] See also Figure 3 As shown, in this embodiment, the cemented lens group 4 includes a first cemented biconvex positive lens 41, a cemented biconcave negative lens 42, and a second cemented biconvex positive lens 43, which are sequentially bonded and arranged along the optical axis from the object side to the imaging side. The object side surface and the image side surface of the first cemented biconvex positive lens 41 are both convex surfaces, the object side surface and the image side surface of the cemented biconcave negative lens 42 are both concave surfaces, and the object side surface and the image side surface of the second cemented biconvex positive lens 43 are both convex surfaces. The image side surface of the first cemented biconvex positive lens 41 is bonded to the object side surface of the cemented biconcave negative lens 42, and the image side surface of the cemented biconcave negative lens 42 is bonded to the object side surface of the second cemented biconvex positive lens 43. The optical focal length of the cemented lens group 4 satisfies: 0.04≤absolute value of optical focal length≤0.08. The preferred absolute value of optical focal length of the cemented lens group 4 in this embodiment is 0.062, and it can also be an optical focal length value within other optical focal length ranges.

[0051] The refractive index range of the first cemented biconvex positive lens 41 is 1.40≤n≤1.45, and the dispersion range is 80≤ν≤95. In this embodiment, the first cemented biconvex positive lens 41 is preferably made of N-FK58 glass material, whose refractive index is 1.46 and dispersion is 90.90, and can also be glass materials within other refractive index ranges and dispersion ranges. The refractive index range of the cemented biconcave negative lens 42 is 1.85≤n≤1.90, and the dispersion range is 30≤ν≤45. In this embodiment, the cemented biconcave negative lens 42 is preferably made of N-LASF31A glass material, whose refractive index is 1.88 and dispersion is 40.76, and can also be glass materials within other refractive index ranges and dispersion ranges. The refractive index range of the second cemented biconvex positive lens 43 is 1.40≤n≤1.45, and the dispersion range is 80≤ν≤95. In this embodiment, the second cemented biconvex positive lens 43 is preferably made of N-FK58 glass material, which has a refractive index of 1.46 and a dispersion of 90.90. It can also be made of glass materials within other refractive index ranges and dispersion ranges.

[0052] Specifically, in this embodiment, the rear lens 5 is a double convex lens with negative optical power, and its object side and image side are both convex, 0.05≤optical power absolute value≤0.08, and the rear lens 5 of this embodiment preferably has an optical power absolute value of 0.076, and may also have an optical power value within other optical power ranges. The refractive index range of the rear lens 5 is 1.60≤n≤1.70, and the dispersion range is 55≤ν≤65. The rear lens 5 of this embodiment preferably has a glass material of model N-SK14, whose refractive index is 1.60 and dispersion is 60.60, and may also be a glass material within other refractive index ranges and dispersion ranges.

[0053] The surface parameters of all lenses in the embodiment of the present invention are as follows:

[0054] surface Surface type Radius of curvature Center thickness Material 1 Spherical 85.55 7.50 N-PK51 2 Spherical 37.12 18.76 3 Spherical 83.13 5.00 N-SK14 4 Aspheric 19.68 22.31 5 Spherical Infinity 4.13 N-SK14 6 Spherical 38.67 12.05 7 Spherical -36.89 9.30 N-SF15 8 Spherical 239.42 12.59 9 Spherical -115.90 11.71 N-KZFS4 10 Spherical -38.78 1.03 11 Spherical 57.32 9.23 N-KZFS4 12 Spherical -2795.61 69.30 13 (aperture stop) —— Infinity 1.12 14 Spherical -34.96 3.00 N-SF15 15 Spherical -21.23 1.00 16 Spherical 57.89 3.50 N-FK58 17 Spherical -8.54 5.07 N-LASF31A 18 Spherical 21.32 2.83 N-FK58 19 Spherical -34.07 0.26 20 Spherical 38.17 5.33 N-SK14 21 Aspheric -10.57 26

[0055] It is worth noting that in the embodiment of the present invention, the image side surface of the second lens and the image side surface of the rear lens are both aspherical surfaces, and the aspherical surface shapes of the second lens and the rear lens satisfy the equation, and the aspherical surface equation is

[0056]

[0057] Among them, z is the aspheric surface sag, c is the aspheric surface vertex curvature, y is the aperture, k is the cone coefficient, A4 is the 4th aspheric surface coefficient, A6 is the 6th aspheric surface coefficient, A8 is the 8th aspheric surface coefficient, A 10 is the 10th-order aspheric coefficient.

[0058] In this embodiment, the two aspheric coefficients are as follows:

[0059] Serial number Component Type k A4 A6 A8 A10 4 Aspheric -1.00 0 0 0 0 21 Aspheric -0.92 0 0 0 0

[0060] The effective focal length of the imaging lens of the present embodiment is f=3.5mm, the full field angle is 118°, the working band is 380-865nm, the aperture number, that is, the ratio of the effective focal length f to the entrance pupil diameter ENPD is 4.3, the total optical length is 230mm, the clear aperture of the first lens is 105mm, and the incident angle CRA of the chief light of all fields of view on the image plane is not greater than 2°, achieving a large field of view and image telecentricity, and the illumination of the edge field of view image plane is better than 85%. The imaging lens of the present embodiment can be applied to multi-spectral large-field imaging fields such as the front objective lens of a long slit imaging spectrometer and a multi-angle multi-spectral polarization camera.

[0061] like Figure 4 The figure shows a modulation transfer function (MTF) curve of a UV to visible wide field low distortion optical lens provided by this embodiment, in which the abscissa represents the spatial frequency in line pairs per millimeter (lp / mm), and the ordinate represents the MTF value. The figure shows that at a spatial frequency of 42l p / mm, the MTF of all fields of view is greater than 0.70, indicating that the optical lens has good imaging quality on the entire image plane.

[0062] like Figure 5 FIG. 1 is a distortion curve of an ultraviolet to visible large field of view low distortion optical lens provided in this embodiment, wherein the horizontal axis is relative distortion and the vertical axis is field of view. Figure 4 It is shown that the relative distortion DI ST of all fields of view is less than 2%.

[0063] like Figure 6 The figure shows a lateral chromatic aberration curve of an ultraviolet to visible large field of view low distortion optical lens provided by this embodiment. In the figure, the abscissa represents the lateral chromatic aberration, and the ordinate represents the normalized field of view. Figure 5 It is shown in the figure that the lateral chromatic aberration of the ultraviolet to visible wide field low distortion optical lens provided in this embodiment is less than 7um, and the lateral chromatic aberration is well corrected.

[0064] The above is a detailed description of the preferred embodiments of the present invention, which cannot be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. An ultraviolet to visible wide field low distortion optical lens, characterized by: The invention comprises a front lens group, an aperture stop, a seventh lens, a cemented lens group and a rear lens which are arranged in sequence from the object side to the imaging side along the optical axis. The cemented lens group comprises a No. 1 cemented biconvex positive lens, a cemented biconcave negative lens and a No. 2 cemented biconvex positive lens which are arranged in sequence from the object side to the imaging side along the optical axis. The object side surface and the image side surface of the No. 1 cemented biconvex positive lens are both convex surfaces, the object side surface and the image side surface of the cemented biconcave negative lens are both concave surfaces, and the object side surface and the image side surface of the No. 2 cemented biconvex positive lens are both convex surfaces, wherein the image side surface of the No. 1 cemented biconvex positive lens is cemented to the object side surface of the cemented biconcave negative lens, and the image side surface of the cemented biconcave negative lens is cemented to the object side surface of the No. 2 cemented biconvex positive lens. The optical power of the cemented lens group satisfies the following requirements: 0.04≤absolute value of optical power≤0.

08.

2. The ultraviolet to visible wide field low distortion optical lens according to claim 1, characterized in that: The refractive index range of the No. 1 glued biconvex positive lens is 1.40≤n≤1.45, and the dispersion range is 80≤ν≤95; the refractive index range of the glued biconcave negative lens is 1.85≤n≤1.90, and the dispersion range is 30≤ν≤45; the refractive index range of the No. 2 glued biconvex positive lens is 1.40≤n≤1.45, and the dispersion range is 80≤ν≤95.

3. The ultraviolet to visible wide field low distortion optical lens according to claim 1, characterized in that: The front lens group comprises: A first lens having negative optical power, whose object side surface is convex, image side surface is concave, 0.005≤optical power absolute value≤0.01, and the first lens has a clear aperture of less than 120 mm; The second lens with negative optical power has a convex object side surface and a concave image side surface, and the absolute value of the optical power is 0.01≤≤0.03; The third lens with negative optical power has a flat object side surface and a concave image side surface, and the absolute value of the optical power is 0.01≤≤0.02; The fourth lens element has negative power, both the object side surface and the image side surface are concave, and the absolute value of the power is 0.02≤≤0.04; A fifth lens having positive refractive power, whose object side surface is concave, whose image side surface is convex, and whose absolute value of refractive power is 0.01≤≤0.02; The sixth lens element has positive refractive power, both the object side surface and the image side surface are convex, and the absolute value of the refractive power is 0.01≤≤0.02; The first lens to the sixth lens are sequentially arranged from the object side to the imaging side along the optical axis.

4. The ultraviolet to visible wide field low distortion optical lens according to claim 3, characterized in that: The refractive index range of the first lens is 1.40≤n≤1.55, and the dispersion range is 70≤ν≤90; the refractive index range of the second lens is 1.60≤n≤1.70, and the dispersion range is 55≤ν≤65; the refractive index range of the third lens is 1.60≤n≤1.70, and the dispersion range is 55≤ν≤65; the refractive index range of the fourth lens is 1.65≤n≤1.80, and the dispersion range is 25≤ν≤40; the refractive index range of the fifth lens is 1.60≤n≤1.70, and the dispersion range is 40≤ν≤45; the refractive index range of the sixth lens is 1.60≤n≤1.70, and the dispersion range is 40≤ν≤45.

5. The ultraviolet to visible wide field low distortion optical lens according to claim 3, characterized in that: The image side surface of the second lens and the image side surface of the rear lens are both aspherical surfaces.

6. The ultraviolet to visible wide field low distortion optical lens according to claim 5, characterized in that: The aspheric surface shapes of the second lens and the rear lens satisfy the equation: Among them, z is the aspheric surface sag, c is the aspheric surface vertex curvature, y is the aperture, k is the cone coefficient, A4 is the 4th aspheric surface coefficient, A6 is the 6th aspheric surface coefficient, A8 is the 8th aspheric surface coefficient, A 10 is the 10th-order aspheric coefficient.

7. The ultraviolet to visible wide field low distortion optical lens according to claim 1, characterized in that: The seventh lens is a positive meniscus lens with positive optical power, whose object side surface is concave and image side surface is convex, and the absolute value of the optical power is 0.01≤≤0.

04. The refractive index range of the seventh lens is 1.65≤n≤1.80, and the dispersion range is 25≤ν≤40.

8. The ultraviolet to visible wide field low distortion optical lens according to claim 1, characterized in that: The rear lens is a double convex lens with negative optical power, the object side and the image side are both convex, the absolute value of the optical power is 0.05≤≤0.08, the refractive index range of the rear lens is 1.60≤n≤1.70, and the dispersion range is 55≤ν≤65.

9. The ultraviolet to visible wide field low distortion optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 4≤f / EPD; the back focus BFL of the optical lens and the total optical length TTL of the optical lens satisfy: 0.08≤BFL / TTL≤0.15; the relative distortion DI ST of the optical lens satisfies: DI ST≤2.5%.

10. The ultraviolet to visible wide field low distortion optical lens according to claim 1, characterized in that: The incident angle CRA of the chief rays of all fields of view on the image plane satisfies: CRA≤3°.

Images