CN117192740A - Wide angle lens - Google Patents

Wide angle lens Download PDF

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Publication number
CN117192740A
CN117192740A CN202210610059.7A CN202210610059A CN117192740A CN 117192740 A CN117192740 A CN 117192740A CN 202210610059 A CN202210610059 A CN 202210610059A CN 117192740 A CN117192740 A CN 117192740A
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China
Prior art keywords
lens
wide
angle
image side
present
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CN202210610059.7A
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Chinese (zh)
Inventor
小宫山忠史
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Nidec Instruments Corp
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Nidec Sankyo Corp
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Priority to CN202210610059.7A priority Critical patent/CN117192740A/en
Publication of CN117192740A publication Critical patent/CN117192740A/en
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Abstract

A wide-angle lens is provided which contributes to reducing the variation in focal position and angle of view due to temperature variation while reducing the size in the optical axis direction. In the wide-angle lens of the present invention, the front lens group is composed of a first lens, a second lens, and a third lens arranged in order from the object side toward the image side, the rear lens group is composed of a fourth lens, a fifth lens, and a sixth lens arranged in order from the object side toward the image side, the first lens is a negative lens having a concave lens surface toward the image side, the second lens is a negative lens having a concave lens surface toward the object side, the third lens is a lens having a concave lens surface toward the object side and a convex lens surface toward the image side, the fourth lens is a glass lens having a convex lens surface toward the object side and a convex lens surface toward the image side, the fifth lens is a lens having a concave lens surface toward the image side, and the sixth lens is a lens having a convex lens surface toward the object side and a convex lens surface toward the image side.

Description

Wide angle lens
Technical Field
The present invention relates to a wide angle lens.
Background
In a vehicle or the like, a wide-angle lens may be used, which generally includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens, which are arranged in this order from an object side toward an image side, and a seven-lens structure is formed, wherein the seventh lens is a single lens made of plastic and is separate from the sixth lens.
However, in practice, there are cases where the space for mounting the above-described wide-angle lens on the vehicle is limited in length in the optical axis direction of the wide-angle lens, and therefore, it is desirable to be able to reduce the optical axis direction dimension of the wide-angle lens.
In practice, the temperature of the environment in which the wide-angle lens is located may vary greatly, and therefore, it is desirable to reduce the variation in focal position and angle of view due to the temperature variation.
Disclosure of Invention
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a wide-angle lens that contributes to reducing the size in the optical axis direction and reducing the fluctuation of the focal position and the angle of view due to the temperature change.
In order to achieve the above object, the present invention provides a wide-angle lens including, in order from an object side toward an image side, a front lens group composed of a first lens, a second lens, and a third lens arranged in order from the object side toward the image side, a rear lens group composed of a fourth lens, a fifth lens, and a sixth lens arranged in order from the object side toward the image side, the first lens being a negative lens having a concave lens surface toward the image side, the second lens being a negative lens having a concave lens surface toward the object side, the third lens being a lens having a concave lens surface toward the object side and a convex lens surface toward the image side, the fourth lens being a glass lens having a convex lens surface toward the object side and a convex lens surface toward the image side, the fifth lens being a lens having a concave lens surface toward the image side, and the sixth lens having a convex lens surface toward the object side and a convex lens surface toward the image side.
According to the wide-angle lens of the present invention, the wide-angle lens includes, in order from the object side toward the image side, a front lens group composed of a first lens, a second lens, and a third lens arranged in order from the object side toward the image side, and a rear lens group composed of a fourth lens, a fifth lens, and a sixth lens arranged in order from the object side toward the image side, the first lens being a negative lens having a concave lens surface toward the image side, the second lens being a negative lens having a concave lens surface toward the object side, the third lens being a lens having a concave lens surface toward the object side and a convex lens surface toward the image side, the fourth lens being a glass lens having a convex lens surface toward the object side and a convex lens surface toward the image side, and the fifth lens being a lens having a convex lens surface toward the object side and a convex lens surface toward the image side, and therefore contributing to reducing the variation in focal position and angle of view due to the temperature change while reducing the size in the optical axis direction.
In the wide-angle lens of the present invention, when the radius of curvature of the object-side lens surface of the fourth lens is R41 and the radius of curvature of the image-side lens surface of the fourth lens is R42, the following relationship is preferably satisfied: 10.000 < (R41+R42)/(R41-R42) < 1.000.
According to the wide-angle lens of the present invention, when the radius of curvature of the object-side lens surface of the fourth lens is R41 and the radius of curvature of the image-side lens surface of the fourth lens is R42, the following relationship is satisfied: since 10.000 < (R41+R42)/(R41-R42) < 1.000, various deviations such as curvature of field, chromatic aberration of magnification and coma can be appropriately corrected.
In the wide-angle lens of the present invention, when the entire focal distance is f0 and the focal distance of the fourth lens is f4, the following relationship is preferably satisfied: 2.000 < f4/f0 < 3.000.
According to the wide-angle lens of the present invention, when the entire focal distance is set to f0 and the focal distance of the fourth lens is set to f4, the following relationship is satisfied: by making f4/f0 larger than 2.000 as the lower limit, the optical power of the fourth lens can be prevented from becoming too strong, and various deviations can be appropriately corrected, while by making f4/f0 smaller than 3.000 as the upper limit, the lens diameter and the inter-object distance can be reduced, and thus the wide-angle lens can be miniaturized.
In the wide-angle lens of the present invention, when the focal length of the entire lens is f0 and the radius of curvature of the image-side lens surface of the fourth lens is R42, the following relationship is preferably satisfied: -3.000 < R42/f0 < -1.800.
According to the wide-angle lens of the present invention, when the entire focal distance is set to f0 and the radius of curvature of the image-side lens surface of the fourth lens is set to R42, the following relationship is satisfied: by making R42/f0 larger than-3.000 as the lower limit, various deviations can be appropriately corrected, while by making R42/f0 smaller than-1.800 as the upper limit, the radius of curvature of the image side lens surface of the fourth lens can be suppressed from becoming too small, whereby the image side lens surface of the fourth lens can be easily molded.
In the wide-angle lens of the present invention, when the total focal length is f0 and the combined focal length of the first lens, the second lens, and the third lens is f123, the following relationship is preferably satisfied: -4.000 < f123/f0 < -1.000.
According to the wide-angle lens of the present invention, when the entire focal distance is set to f0 and the combined focal distance of the first lens, the second lens, and the third lens is set to f123, the following relationship is satisfied: by making f123/f0 larger than-4.000 as the lower limit, it is possible to avoid excessively weak optical power of the front lens group, thereby enabling miniaturization of the wide-angle lens, while by making f123/f0 smaller than-1.000 as the upper limit, it is possible to avoid excessively strong optical power of the front lens group, thereby enabling correction of various deviations appropriately, thereby enabling excellent optical performance.
In the wide-angle lens of the present invention, when the combined focal distance of the first lens, the second lens, and the third lens is f123 and the combined focal distance of the fourth lens, the fifth lens, and the sixth lens is f456, the following relationship is preferably satisfied: -2.500 < f123/f456 < -1.000.
According to the wide-angle lens of the present invention, when the combined focal distance of the first lens, the second lens, and the third lens is set to f123 and the combined focal distance of the fourth lens, the fifth lens, and the sixth lens is set to f456, the following relationship is satisfied: by making f123/f456 smaller than-2.500, the optical power of the front lens group can be prevented from becoming too weak, and thus the wide-angle lens can be miniaturized, while by making f123/f456 smaller than-1.000, the optical power of the front lens group can be prevented from becoming too strong, and thus various deviations can be appropriately corrected, and excellent optical performance can be achieved.
In the wide-angle lens of the present invention, it is preferable that the third lens and the fourth lens are both positive lenses.
According to the wide-angle lens of the present invention, the third lens and the fourth lens are both positive lenses, and therefore, negative optical powers of the first lens and the second lens can be enhanced, whereby lens diameters of the first lens and the second lens can be reduced, thereby achieving miniaturization of the lens system.
Further, in the wide-angle lens of the present invention, it is preferable that the first lens is a glass lens or a plastic lens, and the second lens, the third lens, the fifth lens, and the sixth lens are plastic lenses, respectively.
(effects of the invention)
According to the present invention, the lens system includes, in order from the object side toward the image side, a front lens group composed of a first lens, a second lens, and a third lens arranged in order from the object side toward the image side, and a rear lens group composed of a fourth lens, a fifth lens, and a sixth lens arranged in order from the object side toward the image side, the first lens being a negative lens having a concave lens surface toward the image side, the second lens being a negative lens having a concave lens surface toward the object side, the third lens being a lens having a concave lens surface toward the object side and a convex lens surface toward the image side, the fourth lens being a glass lens having a convex lens surface toward the object side and a convex lens surface toward the image side, the fifth lens being a lens having a convex lens surface toward the image side, and the sixth lens being a lens having a convex lens surface toward the object side, so that it is advantageous to reduce variations in focal position and angle of view due to temperature variations while reducing the size in the optical axis direction.
Drawings
Fig. 1 is an explanatory diagram showing a wide-angle lens according to embodiment 1 of the present invention.
Fig. 2A is an explanatory diagram showing curvature of field of the wide-angle lens of embodiment 1 of the present invention.
Fig. 2B is an explanatory diagram showing distortion of the wide-angle lens according to embodiment 1 of the present invention.
Fig. 3A is an explanatory diagram showing a vertical chromatic aberration (lateral chromatic aberration) of the wide-angle lens of embodiment 1 of the present invention.
Fig. 3B is an explanatory diagram showing spherical aberration (longitudinal aberration) of the wide-angle lens of embodiment 1 of the present invention.
Fig. 4A to 4G are explanatory views showing lateral aberrations of the wide-angle lens according to embodiment 1 of the present invention.
Fig. 5 is an explanatory diagram showing a wide-angle lens according to embodiment 2 of the present invention.
Fig. 6A is an explanatory diagram showing curvature of field of the wide-angle lens of embodiment 2 of the present invention.
Fig. 6B is an explanatory diagram showing distortion of the wide-angle lens according to embodiment 2 of the present invention.
Fig. 7A is an explanatory diagram showing a vertical chromatic aberration (lateral chromatic aberration) of the wide-angle lens of embodiment 2 of the present invention.
Fig. 7B is an explanatory diagram showing spherical aberration (longitudinal aberration) of the wide-angle lens of embodiment 2 of the present invention.
Fig. 8A to 8G are explanatory views showing lateral aberrations of the wide-angle lens according to embodiment 2 of the present invention.
Fig. 9 is an explanatory diagram showing a wide-angle lens according to embodiment 3 of the present invention.
Fig. 10A is an explanatory diagram showing curvature of field of the wide-angle lens of embodiment 3 of the present invention.
Fig. 10B is an explanatory diagram showing distortion of the wide-angle lens according to embodiment 3 of the present invention.
Fig. 11A is an explanatory diagram showing a vertical chromatic aberration (lateral chromatic aberration) of the wide-angle lens of embodiment 3 of the present invention.
Fig. 11B is an explanatory diagram showing spherical aberration (longitudinal aberration) of the wide-angle lens of embodiment 3 of the present invention.
Fig. 12A to 12G are explanatory views showing lateral aberrations of the wide-angle lens according to embodiment 3 of the present invention.
Fig. 13 is an explanatory diagram showing a wide-angle lens according to embodiment 4 of the present invention.
Fig. 14A is an explanatory diagram showing curvature of field of the wide-angle lens of embodiment 4 of the present invention.
Fig. 14B is an explanatory diagram showing distortion of the wide-angle lens according to embodiment 4 of the present invention.
Fig. 15A is an explanatory diagram showing a vertical chromatic aberration (lateral chromatic aberration) of the wide-angle lens of embodiment 4 of the present invention.
Fig. 15B is an explanatory diagram showing spherical aberration (longitudinal aberration) of the wide-angle lens of embodiment 4 of the present invention.
Fig. 16A to 16G are explanatory views showing lateral aberrations of the wide-angle lens according to embodiment 4 of the present invention.
Fig. 17 is an explanatory diagram showing a wide-angle lens according to embodiment 5 of the present invention.
Fig. 18A is an explanatory diagram showing curvature of field of the wide-angle lens according to embodiment 5 of the present invention.
Fig. 18B is an explanatory diagram showing distortion of the wide-angle lens according to embodiment 5 of the present invention.
Fig. 19A is an explanatory diagram showing a vertical chromatic aberration (lateral chromatic aberration) of the wide-angle lens of embodiment 5 of the present invention.
Fig. 19B is an explanatory diagram showing spherical aberration (longitudinal aberration) of the wide-angle lens of embodiment 5 of the present invention.
Fig. 20A to 20G are explanatory views showing lateral aberrations of the wide-angle lens according to embodiment 5 of the present invention.
(symbol description)
1000. Wide angle lens
110. First lens
120. Second lens
130. Third lens
140. Fourth lens
150. Fifth lens
160. Sixth lens
FR front lens group
RR rear lens group
AP aperture
FD aperture
FL filter
SE image pickup element
FP focal plane
Detailed Description
Embodiments of the wide-angle lens of the present invention will be described below with reference to the drawings. In the following description, the object side is denoted by L1 and the image side is denoted by L2 in the extending direction of the optical axis L.
(embodiment 1)
Fig. 1 is an explanatory view showing a wide-angle lens according to embodiment 1 of the present invention, fig. 2A is an explanatory view showing a field curvature of the wide-angle lens according to embodiment 1 of the present invention, fig. 2B is an explanatory view showing distortion of the wide-angle lens according to embodiment 1 of the present invention, fig. 3A is an explanatory view showing a vertical chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to embodiment 1 of the present invention, fig. 3B is an explanatory view showing spherical aberration (longitudinal aberration) of the wide-angle lens according to embodiment 1 of the present invention, and fig. 4A to 4G are explanatory views showing lateral aberration of the wide-angle lens according to embodiment 1 of the present invention. Here, in fig. 2A, 2B, 3A, 3B, and 4A to 4G, a correlation curve of red light R (wavelength: 656 nm) is denoted by R, a correlation curve of green light G (wavelength: 546 nm) is denoted by G, a correlation curve of blue light B (wavelength: 486 nm) is denoted by B, a correlation with a meridian plane is denoted by T, a correlation with a sagittal plane is denoted by S, and a Maximum size of a vertical axis (Maximum Scale) is ±50.000 μm in fig. 4A to 4G.
As shown in fig. 1, the wide-angle lens 100 includes, in order from the object side (L1 side) toward the image side (L2 side), a front lens group FR composed of a first lens 110, a second lens 120, and a third lens 130 arranged in order from the object side toward the image side, an aperture stop AP, and a rear lens group RR composed of a fourth lens 140, a fifth lens 150, and a sixth lens 160 arranged in order from the object side toward the image side.
Here, the first lens 110 is a negative lens (i.e., has negative optical power) having a concave lens surface facing the image side. Specifically, the first lens 110 is a negative lens having a convex lens surface (first surface 1) facing the object side L1 and a concave lens surface (second surface 2) facing the image side L2. The first lens 110 is a glass lens having spherical surfaces on the first surface 1 and the second surface 2.
The second lens 120 is a negative lens having a concave lens surface facing the object side. Specifically, the second lens 120 is a negative lens having a concave lens surface (third surface 3) facing the object side L1 and a convex lens surface (fourth surface 4) facing the image side L2. The second lens 120 is a plastic lens having aspherical third and fourth surfaces 3 and 4.
The third lens 130 is a lens having a concave lens surface facing the object side and a convex lens surface facing the image side. Specifically, the third lens 130 is a positive lens (i.e., has positive optical power) having a concave lens surface (fifth surface 5) toward the object side L1 and a convex lens surface (sixth surface 6) toward the image side L2. The third lens 130 is a plastic lens having aspherical surfaces on the fifth surface 5 and the sixth surface 6.
The fourth lens 140 is a lens having a convex lens surface facing the object side and a convex lens surface facing the image side. Specifically, the fourth lens 140 is a positive lens (i.e., has positive optical power) having a convex lens surface (eighth surface 8) toward the object side L1 and a convex lens surface (ninth surface 9) toward the image side L2. The fourth lens 140 is a glass lens having spherical surfaces on the eighth surface 8 and the ninth surface 9.
The fifth lens 150 is a lens having a concave lens surface facing the image side. Specifically, the fifth lens 150 is a lens having a convex lens surface (tenth surface 10) facing the object side L1 and a concave lens surface (tenth surface 11) facing the image side. The fifth lens 150 is a plastic lens having aspherical surfaces on the tenth surface 10 and the tenth surface 11.
The sixth lens 160 is a lens having a convex lens surface facing the object side and a convex lens surface facing the image side. Specifically, the sixth lens 160 is a lens having a convex lens surface (tenth surface 11) facing the object side L1 and a convex lens surface (tenth surface 12) facing the image side. The sixth lens 160 is a plastic lens having an aspherical surface on the eleventh surface 11 and the twelfth surface 12.
The fifth lens 150 and the sixth lens 160 are joined lenses in which a surface of the fifth lens 150 facing the image side and a surface of the sixth lens 160 facing the object side are joined.
In the present embodiment, as shown in fig. 1, a diaphragm AP (specifically, an aperture stop) is provided between the third lens 130 and the fourth lens 140, a diaphragm FD (specifically, a field stop) is provided between the fourth lens 140 and the fifth lens 150, a filter FL is disposed on the image side of the sixth lens 160, and an image pickup element SE is disposed on the image side of the filter FL. Also shown in fig. 1 is the focal plane FP.
In the present embodiment, the focal distance F (Effective Focal Length) of the entire lens system is 5.428mm, the inter-object-Image distance d (Total Track) is 34.063mm, the F-number (Image Space F/#) is 1.800, the maximum half Angle (max. Field of Angle) is 66.085 degrees, the entrance pupil diameter HEP is 3.015mm, and the distance between the object-side lens surface of the first lens 110 and the Image-side lens surface of the sixth lens 160 is 27.365mm.
Physical properties of each surface of wide-angle lens 1000 of the present embodiment are shown in table 1, and aspherical coefficients of each surface of wide-angle lens 1000 of the present embodiment are shown in tables 2-1 and 2-2.
(Table 1)
In table 1 above, the unit of the radius of curvature, thickness, focal distance, and effective radius is mm, nd is the refractive index for 546 nm light, vd is abbe number, and x represents an aspherical surface.
(Table 2-1)
Flour with a plurality of grooves c (1/radius of curvature) K A4 A6
3 -8.96766E-02 0.00000E+00 3.09047E-04 -3.76848E-05
4 -3.59868E-02 0.00000E+00 1.14574E-03 -9.16714E-05
5 -1.04721E-01 0.00000E+00 2.28123E-04 -6.72814E-05
6 -1.18755E-01 0.00000E+00 1.51721E-04 -1.83994E-05
10 5.31784E-02 0.00000E+00 -1.67645E-05 -1.58259E-05
11 2.08243E-01 -2.60000E+00 3.19833E-03 -1.40522E-04
12 -6.12703E-02 0.00000E+00 -3.53144E-05 8.25539E-07
(Table 2-2)
Flour with a plurality of grooves A8 A10 A12 A14 A16
3 1.31045E-06 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
4 2.01955E-06 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
5 4.21755E-07 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
6 4.78109E-07 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
10 1.50817E-07 9.05225E-10 0.00000E+00 0.00000E+00 0.00000E+00
11 2.38759E-06 -2.81618E-08 0.00000E+00 0.00000E+00 0.00000E+00
12 -2.68454E-08 2.51424E-09 0.00000E+00 0.00000E+00 0.00000E+00
In tables 2-1 and 2-2 above, the radius of curvature is set to a positive value when the lens surface is a convex lens surface protruding toward the object side or a concave lens surface recessed toward the object side, and the radius of curvature is set to a negative value when the lens surface is a convex lens surface protruding toward the image side or a concave lens surface recessed toward the image side.
Table 2-1 and table 2-2 above show the aspherical coefficients A4, A6, A8, a10, a12, a14, and a16 when the aspherical shape of each surface is expressed by the following expression (expression 1). In the following expression, the sagittal height (the axis in the optical axis direction) is Z, the height in the direction perpendicular to the optical axis (the light ray height) is r, the conic coefficient is K, and the inverse of the radius of curvature is c.
[ mathematics 1]
(main effects of the present embodiment)
According to the wide-angle lens 100 of the present embodiment, the front lens group FR is composed of the first lens 110, the second lens 120, and the third lens 130 arranged in this order from the object side toward the image side, the rear lens group RR is composed of the fourth lens 140, the fifth lens 150, and the sixth lens 160 arranged in this order from the object side toward the image side, the first lens 110 is a negative lens having a concave lens surface toward the image side, the second lens 120 is a negative lens having a concave lens surface toward the object side, the third lens 130 is a lens having a concave lens surface toward the object side and a convex lens surface toward the image side, the fourth lens 140 is a glass lens having a convex lens surface toward the object side and a convex lens surface toward the image side, the fifth lens 150 is a lens having a concave lens surface toward the image side, and the sixth lens 160 is a lens having a convex lens surface toward the object side and a convex lens surface toward the image side, and therefore, it is advantageous to reduce the focal point position fluctuation due to the dimensional change in the optical axis direction at the same time.
Further, according to the wide-angle lens 100 of the present embodiment, when the radius of curvature of the object-side lens surface of the fourth lens 140 is R41 and the radius of curvature of the image-side lens surface of the fourth lens 140 is R42, the following relationship is satisfied: since (R41+R42)/(R41-R42) < 1.000, as shown in FIGS. 2A to 4G, various deviations such as curvature of field, chromatic aberration of magnification and coma can be appropriately corrected.
Further, according to the wide-angle lens 100 of the present embodiment, when the focal distance of the entire is set to f0 and the focal distance of the fourth lens 140 is set to f4, the following relationship is satisfied: as shown in fig. 2A to 4G, by making f4/f0 larger than 2.000 as a lower limit, as a result, excessive optical power of the fourth lens 140 can be avoided, and various deviations can be appropriately corrected, while by making f4/f0 smaller than 3.000 as an upper limit, the lens diameter and the inter-object distance can be reduced, and thus, miniaturization of the wide-angle lens can be achieved.
Further, according to the wide-angle lens 100 of the present embodiment, when the focal length of the whole is set to f0 and the radius of curvature of the image-side lens surface of the fourth lens 140 is set to R42, the following relationship is satisfied: as shown in fig. 2A to 4G, by making R42/f0 larger than-3.000 as a lower limit, various deviations can be appropriately corrected, while by making R42/f0 smaller than-1.800 as an upper limit, the radius of curvature of the image side lens surface of the fourth lens 140 can be suppressed from becoming too small, and thus, the image side lens surface of the fourth lens 140 can be easily molded.
Further, according to the wide-angle lens 100 of the present embodiment, when the overall focal distance is set to f0 and the combined focal distance of the first lens 110, the second lens 120, and the third lens 130 is set to f123, the following relationship is satisfied: as shown in fig. 2A to 4G, by making f123/f0 larger than-4.000 as a lower limit, it is possible to avoid excessively weak optical power of the front lens group FR, thereby enabling miniaturization of the wide-angle lens, while by making f123/f0 smaller than-1.000 as an upper limit, it is possible to avoid excessively strong optical power of the front lens group FR, thereby enabling appropriate correction of various deviations, thereby achieving excellent optical performance.
Further, according to the wide-angle lens 100 of the present embodiment, when the combined focal distance of the first lens 110, the second lens 120, and the third lens 130 is set to f123, and the combined focal distance of the fourth lens 140, the fifth lens 150, and the sixth lens 160 is set to f456, the following relationship is satisfied: as shown in fig. 2A to 4G, f123/f456 is set to be greater than-2.500, which is a lower limit, whereby the optical power of the front lens group FR can be prevented from becoming too weak, and thus the wide-angle lens can be miniaturized, while f123/f456 is set to be less than-1.000, which is an upper limit, whereby the optical power of the front lens group FR can be prevented from becoming too strong, and thus various deviations can be appropriately corrected, and excellent optical performance can be achieved.
Further, according to the wide-angle lens 100 of the present embodiment, the third lens 130 and the fourth lens 140 are both positive lenses, and therefore, negative optical powers of the first lens 110 and the second lens 120 can be enhanced, whereby lens diameters of the first lens 110 and the second lens 120 can be reduced, thereby achieving miniaturization of the lens system.
(embodiment 2)
Fig. 5 is an explanatory view showing a wide-angle lens according to embodiment 2 of the present invention, fig. 6A is an explanatory view showing a field curvature of the wide-angle lens according to embodiment 2 of the present invention, fig. 6B is an explanatory view showing distortion of the wide-angle lens according to embodiment 2 of the present invention, fig. 7A is an explanatory view showing a vertical chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to embodiment 2 of the present invention, fig. 7B is an explanatory view showing spherical aberration (longitudinal aberration) of the wide-angle lens according to embodiment 2 of the present invention, and fig. 8A to 8G are explanatory views showing lateral aberration of the wide-angle lens according to embodiment 2 of the present invention. Here, in fig. 6A, 6B, 7A, 7B, and 8A to 8G, a correlation curve of red light R (wavelength: 656 nm) is denoted by R, a correlation curve of green light G (wavelength: 546 nm) is denoted by G, a correlation curve of blue light B (wavelength: 486 nm) is denoted by B, correlation with a meridian plane is denoted by T, correlation with a sagittal plane is denoted by S, and in fig. 8A to 8G, a Maximum size of a vertical axis (Maximum Scale) is ±50.000 μm.
As shown in fig. 5, the wide-angle lens 100 includes, in order from the object side (L1 side) toward the image side (L2 side), a front lens group FR composed of a first lens 110, a second lens 120, and a third lens 130 arranged in order from the object side toward the image side, an aperture stop AP, and a rear lens group RR composed of a fourth lens 140, a fifth lens 150, and a sixth lens 160 arranged in order from the object side toward the image side.
Here, since the basic structure of the wide-angle lens 1000 in the present embodiment (i.e., whether the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, and the sixth lens 160 have positive or negative optical power, whether it is a glass lens or a plastic lens, whether the object-side surface and the image-side surface are convex or concave lens surfaces, and whether they are spherical or aspherical) is the same as that of the wide-angle lens in embodiment 1, it will not be explained in detail here.
As shown in fig. 5, as in embodiment 1, a diaphragm AP (specifically, an aperture stop) is provided between the third lens 130 and the fourth lens 140, a diaphragm FD (specifically, a field stop) is provided between the fourth lens 140 and the fifth lens 150, a filter FL is disposed on the image side of the sixth lens 160, and an image pickup element SE is disposed on the image side of the filter FL. Also shown in fig. 5 is the focal plane FP.
In the present embodiment, the focal distance F (Effective Focal Length) of the entire lens system is 5.428mm, the inter-object-Image distance d (Total Track) is 33.784mm, the F-number (Image Space F/#) is 1.800, the maximum half Angle (max. Field of Angle) is 66.092 degrees, the entrance pupil diameter HEP is 3.015mm, and the distance between the object-side lens surface of the first lens 110 and the Image-side lens surface of the sixth lens 160 is 27.030mm.
Physical properties of each surface of wide-angle lens 1000 of the present embodiment are shown in table 3, and aspherical coefficients of each surface of wide-angle lens 1000 of the present embodiment are shown in tables 4-1 and 4-2.
(Table 3)
In table 3 above, the unit of radius of curvature, thickness, focal distance, and effective radius is mm, nd is the refractive index for 546 nm light, vd is abbe number, and x represents an aspherical surface.
(Table 4-1)
Flour with a plurality of grooves c (1/radius of curvature) K A4 A6
3 -8.78484E-02 0.00000E+00 3.16200E-04 -3.55808E-05
4 -3.74400E-02 0.00000E+00 1.12608E-03 -8.49463E-05
5 -1.03397E-01 0.00000E+00 2.80959E-04 -7.02314E-05
6 -1.15180E-01 0.00000E+00 1.55139E-04 -1.75462E-05
10 5.31876E-02 0.00000E+00 -3.11203E-05 -1.59159E-05
11 2.10997E-01 -2.60000E+00 3.33189E-03 -1.39862E-04
12 -5.84747E-02 0.00000E+00 -2.36312E-05 -6.75230E-07
(Table 4-2)
Flour with a plurality of grooves A8 A10 A12 A14 A16
3 1.09738E-06 -6.60946E-11 0.00000E+00 0.00000E+00 0.00000E+00
4 1.76653E-06 -2.11013E-10 0.00000E+00 0.00000E+00 0.00000E+00
5 5.89136E-07 -2.99835E-10 0.00000E+00 0.00000E+00 0.00000E+00
6 4.00576E-07 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
10 2.34739E-07 -1.96763E-09 0.00000E+00 0.00000E+00 0.00000E+00
11 2.38920E-06 -2.80668E-08 0.00000E+00 0.00000E+00 0.00000E+00
12 -1.02840E-09 2.72932E-09 0.00000E+00 0.00000E+00 0.00000E+00
In tables 4-1 and 4-2 above, the radius of curvature is set to a positive value when the lens surface is a convex lens surface protruding toward the object side or a concave lens surface recessed toward the object side, and the radius of curvature is set to a negative value when the lens surface is a convex lens surface protruding toward the image side or a concave lens surface recessed toward the image side.
Table 4-1 and table 4-2 show aspherical coefficients A4, A6, A8, a10, a12, a14, and a16 when the aspherical shape of each surface is expressed by the above equation 1.
(main effects of the present embodiment)
According to the wide-angle lens 100 of the present embodiment, the front lens group FR is composed of the first lens 110, the second lens 120, and the third lens 130 arranged in this order from the object side toward the image side, the rear lens group RR is composed of the fourth lens 140, the fifth lens 150, and the sixth lens 160 arranged in this order from the object side toward the image side, the first lens 110 is a negative lens having a concave lens surface toward the image side, the second lens 120 is a negative lens having a concave lens surface toward the object side, the third lens 130 is a lens having a concave lens surface toward the object side and a convex lens surface toward the image side, the fourth lens 140 is a glass lens having a convex lens surface toward the object side and a convex lens surface toward the image side, the fifth lens 150 is a lens having a concave lens surface toward the image side, and the sixth lens 160 is a lens having a convex lens surface toward the object side and a convex lens surface toward the image side, and therefore, it is advantageous to reduce the focal point position fluctuation due to the dimensional change in the optical axis direction at the same time.
Further, according to the wide-angle lens 100 of the present embodiment, when the radius of curvature of the object-side lens surface of the fourth lens 140 is R41 and the radius of curvature of the image-side lens surface of the fourth lens 140 is R42, the following relationship is satisfied: since (R41+R42)/(R41-R42) < 1.000, as shown in FIGS. 6A to 8G, various deviations such as curvature of field, chromatic aberration of magnification and coma can be appropriately corrected.
Further, according to the wide-angle lens 100 of the present embodiment, when the focal distance of the entire is set to f0 and the focal distance of the fourth lens 140 is set to f4, the following relationship is satisfied: as shown in fig. 6A to 8G, by making f4/f0 larger than 2.000 as a lower limit, as a result, excessive optical power of the fourth lens 140 can be avoided, and various deviations can be appropriately corrected, while by making f4/f0 smaller than 3.000 as an upper limit, the lens diameter and the inter-object distance can be reduced, and thus, miniaturization of the wide-angle lens can be achieved.
Further, according to the wide-angle lens 100 of the present embodiment, when the focal length of the whole is set to f0 and the radius of curvature of the image-side lens surface of the fourth lens 140 is set to R42, the following relationship is satisfied: as shown in fig. 6A to 8G, by making R42/f0 larger than-3.000 as a lower limit, various deviations can be appropriately corrected, while by making R42/f0 smaller than-1.800 as an upper limit, the radius of curvature of the image side lens surface of the fourth lens 140 can be suppressed from becoming too small, and thus, the image side lens surface of the fourth lens 140 can be easily molded.
Further, according to the wide-angle lens 100 of the present embodiment, when the overall focal distance is set to f0 and the combined focal distance of the first lens 110, the second lens 120, and the third lens 130 is set to f123, the following relationship is satisfied: as shown in fig. 6A to 8G, by making f123/f0 larger than-4.000 as a lower limit, it is possible to avoid excessively weak optical power of the front lens group FR, thereby enabling miniaturization of the wide-angle lens, while by making f123/f0 smaller than-1.000 as an upper limit, it is possible to avoid excessively strong optical power of the front lens group FR, thereby enabling appropriate correction of various deviations, thereby achieving excellent optical performance.
Further, according to the wide-angle lens 100 of the present embodiment, when the combined focal distance of the first lens 110, the second lens 120, and the third lens 130 is set to f123, and the combined focal distance of the fourth lens 140, the fifth lens 150, and the sixth lens 160 is set to f456, the following relationship is satisfied: as shown in fig. 6A to 8G, by making f123/f456 greater than-2.500 as the lower limit, it is possible to avoid excessively weak optical power of the front lens group FR, thereby enabling miniaturization of the wide-angle lens, while by making f123/f456 smaller than-1.000 as the upper limit, it is possible to avoid excessively strong optical power of the front lens group FR, thereby enabling appropriate correction of various deviations, thereby achieving excellent optical performance.
Further, according to the wide-angle lens 100 of the present embodiment, the third lens 130 and the fourth lens 140 are both positive lenses, and therefore, negative optical powers of the first lens 110 and the second lens 120 can be enhanced, whereby lens diameters of the first lens 110 and the second lens 120 can be reduced, thereby achieving miniaturization of the lens system.
Embodiment 3
Fig. 9 is an explanatory view showing a wide-angle lens according to embodiment 3 of the present invention, fig. 10A is an explanatory view showing a field curvature of the wide-angle lens according to embodiment 3 of the present invention, fig. 10B is an explanatory view showing distortion of the wide-angle lens according to embodiment 3 of the present invention, fig. 11A is an explanatory view showing a vertical chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to embodiment 3 of the present invention, fig. 11B is an explanatory view showing spherical aberration (longitudinal aberration) of the wide-angle lens according to embodiment 3 of the present invention, and fig. 12A to 12G are explanatory views showing lateral aberration of the wide-angle lens according to embodiment 3 of the present invention. Here, in fig. 10A, 10B, 11A, 11B, and 12A to 12G, a correlation curve of red light R (wavelength: 656 nm) is denoted by R, a correlation curve of green light G (wavelength: 546 nm) is denoted by G, a correlation curve of blue light B (wavelength: 486 nm) is denoted by B, correlation with a meridian plane is denoted by T, correlation with a sagittal plane is denoted by S, and in fig. 12A to 12G, a Maximum size of a vertical axis (Maximum Scale) is ±50.000 μm.
As shown in fig. 9, the wide-angle lens 100 includes, in order from the object side (L1 side) toward the image side (L2 side), a front lens group FR composed of a first lens 110, a second lens 120, and a third lens 130 arranged in order from the object side toward the image side, an aperture stop AP, and a rear lens group RR composed of a fourth lens 140, a fifth lens 150, and a sixth lens 160 arranged in order from the object side toward the image side.
Here, since the basic structure of the wide-angle lens 1000 in the present embodiment (i.e., whether the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, and the sixth lens 160 have positive or negative optical power, whether it is a glass lens or a plastic lens, whether the object-side surface and the image-side surface are convex or concave lens surfaces, and whether they are spherical or aspherical) is the same as that of the wide-angle lens in embodiment 1, it will not be explained in detail here.
As shown in fig. 9, as in embodiment 1, a diaphragm AP (specifically, an aperture stop) is provided between the third lens 130 and the fourth lens 140, a diaphragm FD (specifically, a field stop) is provided between the fourth lens 140 and the fifth lens 150, a filter FL is disposed on the image side of the sixth lens 160, and an image pickup element SE is disposed on the image side of the filter FL. Also shown in fig. 9 is the focal plane FP.
In the present embodiment, the focal distance F (Effective Focal Length) of the entire lens system is 5.432mm, the inter-object-Image distance d (Total Track) is 34.503mm, the F-number (Image Space F/#) is 1.800, the maximum half Angle (max. Field of Angle) is 66.172 degrees, the entrance pupil diameter HEP is 3.018mm, and the distance between the object-side lens surface of the first lens 110 and the Image-side lens surface of the sixth lens 160 is 27.405mm.
Physical properties of each surface of wide-angle lens 1000 of the present embodiment are shown in table 5, and aspherical coefficients of each surface of wide-angle lens 1000 of the present embodiment are shown in tables 6-1 and 6-2.
(Table 5)
In table 5 above, the unit of the radius of curvature, thickness, focal distance, and effective radius is mm, nd is the refractive index for 546 nm light, vd is abbe number, and x represents an aspherical surface.
(Table 6-1)
Flour with a plurality of grooves c (1/radius of curvature) K A4 A6
3 -8.73998E-02 0.00000E+00 3.46307E-04 -4.66241E-05
4 -3.83887E-02 0.00000E+00 1.06809E-03 -1.03308E-04
5 -1.01730E-01 0.00000E+00 2.51483E-04 -7.72186E-05
6 -1.25806E-01 0.00000E+00 6.59475E-05 -1.89348E-05
10 6.70258E-02 0.00000E+00 -6.96272E-05 -1.49854E-05
11 2.48103E-01 -2.60000E+00 3.48314E-03 -1.47215E-04
12 -6.31506E-02 0.00000E+00 6.75221E-05 1.35458E-06
(Table 6-2)
Flour with a plurality of grooves A8 A10 A12 A14 A16
3 2.20084E-07 4.35613E-08 0.00000E+00 0.00000E+00 0.00000E+00
4 7.56810E-07 3.81402E-08 0.00000E+00 0.00000E+00 0.00000E+00
5 2.82025E-08 -1.53691E-08 0.00000E+00 0.00000E+00 0.00000E+00
6 1.11878E-07 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
10 3.02035E-07 -3.05174E-09 0.00000E+00 0.00000E+00 0.00000E+00
11 1.78323E-06 -2.53413E-08 0.00000E+00 0.00000E+00 0.00000E+00
12 -1.28320E-07 1.05286E-08 0.00000E+00 0.00000E+00 0.00000E+00
In tables 6-1 and 6-2 above, the radius of curvature is set to a positive value when the lens surface is a convex lens surface protruding toward the object side or a concave lens surface recessed toward the object side, and the radius of curvature is set to a negative value when the lens surface is a convex lens surface protruding toward the image side or a concave lens surface recessed toward the image side.
Table 6-1 and table 6-2 show aspherical coefficients A4, A6, A8, a10, a12, a14, and a16 when the aspherical shape of each surface is expressed by the above equation 1.
(main effects of the present embodiment)
According to the wide-angle lens 100 of the present embodiment, the front lens group FR is composed of the first lens 110, the second lens 120, and the third lens 130 arranged in this order from the object side toward the image side, the rear lens group RR is composed of the fourth lens 140, the fifth lens 150, and the sixth lens 160 arranged in this order from the object side toward the image side, the first lens 110 is a negative lens having a concave lens surface toward the image side, the second lens 120 is a negative lens having a concave lens surface toward the object side, the third lens 130 is a lens having a concave lens surface toward the object side and a convex lens surface toward the image side, the fourth lens 140 is a glass lens having a convex lens surface toward the object side and a convex lens surface toward the image side, the fifth lens 150 is a lens having a concave lens surface toward the image side, and the sixth lens 160 is a lens having a convex lens surface toward the object side and a convex lens surface toward the image side, and therefore, it is advantageous to reduce the focal point position fluctuation due to the dimensional change in the optical axis direction at the same time.
Further, according to the wide-angle lens 100 of the present embodiment, when the radius of curvature of the object-side lens surface of the fourth lens 140 is R41 and the radius of curvature of the image-side lens surface of the fourth lens 140 is R42, the following relationship is satisfied: since (R41+R42)/(R41-R42) < 1.000, as shown in FIGS. 10A to 12G, various deviations such as curvature of field, chromatic aberration of magnification and coma can be appropriately corrected.
Further, according to the wide-angle lens 100 of the present embodiment, when the focal distance of the entire is set to f0 and the focal distance of the fourth lens 140 is set to f4, the following relationship is satisfied: as shown in fig. 10A to 12G, by making f4/f0 larger than 2.000 as a lower limit, as a result, excessive optical power of the fourth lens 140 can be avoided, and various deviations can be appropriately corrected, while by making f4/f0 smaller than 3.000 as an upper limit, the lens diameter and the inter-object distance can be reduced, and thus, miniaturization of the wide-angle lens can be achieved.
Further, according to the wide-angle lens 100 of the present embodiment, when the focal length of the whole is set to f0 and the radius of curvature of the image-side lens surface of the fourth lens 140 is set to R42, the following relationship is satisfied: as shown in fig. 10A to 12G, by making R42/f0 larger than-3.000 as a lower limit, various deviations can be appropriately corrected, while by making R42/f0 smaller than-1.800 as an upper limit, the radius of curvature of the image side lens surface of the fourth lens 140 can be suppressed from becoming too small, and thus, the image side lens surface of the fourth lens 140 can be easily molded.
Further, according to the wide-angle lens 100 of the present embodiment, when the overall focal distance is set to f0 and the combined focal distance of the first lens 110, the second lens 120, and the third lens 130 is set to f123, the following relationship is satisfied: as shown in fig. 10A to 12G, by making f123/f0 larger than-4.000 as a lower limit, it is possible to avoid excessively weak optical power of the front lens group FR, thereby enabling miniaturization of the wide-angle lens, while by making f123/f0 smaller than-1.000 as an upper limit, it is possible to avoid excessively strong optical power of the front lens group FR, thereby enabling appropriate correction of various deviations, thereby achieving excellent optical performance.
Further, according to the wide-angle lens 100 of the present embodiment, when the combined focal distance of the first lens 110, the second lens 120, and the third lens 130 is set to f123, and the combined focal distance of the fourth lens 140, the fifth lens 150, and the sixth lens 160 is set to f456, the following relationship is satisfied: as shown in fig. 10A to 12G, by making f123/f456 greater than-2.500 as the lower limit, it is possible to avoid excessively weak optical power of the front lens group FR, thereby enabling miniaturization of the wide-angle lens, while by making f123/f456 smaller than-1.000 as the upper limit, it is possible to avoid excessively strong optical power of the front lens group FR, thereby enabling appropriate correction of various deviations, thereby achieving excellent optical performance.
Further, according to the wide-angle lens 100 of the present embodiment, the third lens 130 and the fourth lens 140 are both positive lenses, and therefore, negative optical powers of the first lens 110 and the second lens 120 can be enhanced, whereby lens diameters of the first lens 110 and the second lens 120 can be reduced, thereby achieving miniaturization of the lens system.
Embodiment 4
Fig. 13 is an explanatory view showing a wide-angle lens according to embodiment 4 of the present invention, fig. 14A is an explanatory view showing a field curvature of the wide-angle lens according to embodiment 4 of the present invention, fig. 14B is an explanatory view showing distortion of the wide-angle lens according to embodiment 4 of the present invention, fig. 15A is an explanatory view showing a vertical chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to embodiment 4 of the present invention, fig. 15B is an explanatory view showing spherical aberration (longitudinal aberration) of the wide-angle lens according to embodiment 4 of the present invention, and fig. 16A to 16G are explanatory views showing lateral aberration of the wide-angle lens according to embodiment 4 of the present invention. Here, in fig. 14A, 14B, 15A, 15B, and 16A to 16G, a correlation curve of red light R (wavelength: 656 nm) is denoted by R, a correlation curve of green light G (wavelength: 546 nm) is denoted by G, a correlation curve of blue light B (wavelength: 486 nm) is denoted by B, a correlation with a meridian plane is denoted by T, a correlation with a sagittal plane is denoted by S, and a Maximum size of a vertical axis (Maximum Scale) is ±50.000 μm in fig. 16A to 16G.
As shown in fig. 13, the wide-angle lens 100 includes, in order from the object side (L1 side) toward the image side (L2 side), a front lens group FR composed of a first lens 110, a second lens 120, and a third lens 130 arranged in order from the object side toward the image side, an aperture stop AP, and a rear lens group RR composed of a fourth lens 140, a fifth lens 150, and a sixth lens 160 arranged in order from the object side toward the image side.
Here, since the basic structure of the wide-angle lens 1000 in the present embodiment (i.e., whether the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, and the sixth lens 160 have positive or negative optical power, whether it is a glass lens or a plastic lens, whether the object-side surface and the image-side surface are convex or concave lens surfaces, and whether they are spherical or aspherical) is the same as that of the wide-angle lens in embodiment 1, it will not be explained in detail here.
As shown in fig. 13, as in embodiment 1, a diaphragm AP (specifically, an aperture stop) is provided between the third lens 130 and the fourth lens 140, a diaphragm FD (specifically, a field stop) is provided between the fourth lens 140 and the fifth lens 150, a filter FL is disposed on the image side of the sixth lens 160, and an image pickup element SE is disposed on the image side of the filter FL. Also, the focal plane FP is shown in fig. 13.
In the present embodiment, the focal distance F (Effective Focal Length) of the entire lens system is 5.070mm, the inter-object-Image distance d (Total Track) is 33.741mm, the F-number (Image Space F/#) is 1.800, the maximum half Angle (max. Field of Angle) is 76.936 degrees, the entrance pupil diameter HEP is 2.817mm, and the distance between the object-side lens surface of the first lens 110 and the Image-side lens surface of the sixth lens 160 is 27.535mm.
Physical properties of each surface of wide-angle lens 1000 of the present embodiment are shown in table 7, and aspherical coefficients of each surface of wide-angle lens 1000 of the present embodiment are shown in tables 8-1 and 8-2.
(Table 7)
In table 7 above, the unit of the radius of curvature, thickness, focal length, and effective radius is mm, nd is the refractive index for 546 nm light, vd is abbe number, and x represents an aspherical surface.
(Table 8-1)
Flour with a plurality of grooves c (1/radius of curvature) K A4 A6
3 -1.08462E-01 0.00000E+00 4.75915E-04 -6.21271E-05
4 -3.45924E-02 0.00000E+00 1.19463E-03 -1.10547E-04
5 -1.05999E-01 0.00000E+00 -3.09234E-05 -7.24479E-05
6 -1.31538E-01 0.00000E+00 1.30122E-04 -2.14345E-05
10 6.27877E-02 0.00000E+00 -1.27256E-04 -8.59203E-06
11 2.38916E-01 -2.62000E+00 3.39665E-03 -1.67608E-04
12 -5.49909E-02 0.00000E+00 1.28744E-05 2.48936E-06
(Table 8-2)
Flour with a plurality of grooves A8 A10 A12 A14 A16
3 1.95540E-06 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
4 2.69734E-06 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
5 4.70471E-07 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
6 4.61346E-07 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
10 7.61753E-08 1.27662E-09 0.00000E+00 0.00000E+00 0.00000E+00
11 4.90282E-06 -6.26444E-08 0.00000E+00 0.00000E+00 0.00000E+00
12 -2.01152E-07 3.66429E-09 0.00000E+00 0.00000E+00 0.00000E+00
In tables 8-1 and 8-2 above, the radius of curvature is set to a positive value when the lens surface is a convex lens surface protruding toward the object side or a concave lens surface recessed toward the object side, and the radius of curvature is set to a negative value when the lens surface is a convex lens surface protruding toward the image side or a concave lens surface recessed toward the image side.
Table 8-1 and table 8-2 above show the aspherical coefficients A4, A6, A8, a10, a12, a14, and a16 when the aspherical shapes of the respective surfaces are expressed by the above equation 1.
(main effects of the present embodiment)
According to the wide-angle lens 100 of the present embodiment, the front lens group FR is composed of the first lens 110, the second lens 120, and the third lens 130 arranged in this order from the object side toward the image side, the rear lens group RR is composed of the fourth lens 140, the fifth lens 150, and the sixth lens 160 arranged in this order from the object side toward the image side, the first lens 110 is a negative lens having a concave lens surface toward the image side, the second lens 120 is a negative lens having a concave lens surface toward the object side, the third lens 130 is a lens having a concave lens surface toward the object side and a convex lens surface toward the image side, the fourth lens 140 is a glass lens having a convex lens surface toward the object side and a convex lens surface toward the image side, the fifth lens 150 is a lens having a concave lens surface toward the image side, and the sixth lens 160 is a lens having a convex lens surface toward the object side and a convex lens surface toward the image side, and therefore, it is advantageous to reduce the focal point position fluctuation due to the dimensional change in the optical axis direction at the same time.
Further, according to the wide-angle lens 100 of the present embodiment, when the radius of curvature of the object-side lens surface of the fourth lens 140 is R41 and the radius of curvature of the image-side lens surface of the fourth lens 140 is R42, the following relationship is satisfied: since 10.000 < (R41+R42)/(R41-R42) < 1.000, various deviations such as image plane curvature, chromatic aberration of magnification and coma can be appropriately corrected as shown in FIGS. 14A to 16G.
Further, according to the wide-angle lens 100 of the present embodiment, when the focal distance of the entire is set to f0 and the focal distance of the fourth lens 140 is set to f4, the following relationship is satisfied: as shown in fig. 14A to 16G, by making f4/f0 larger than 2.000 as a lower limit, as a result, excessive optical power of the fourth lens 140 can be avoided, and various deviations can be appropriately corrected, while by making f4/f0 smaller than 3.000 as an upper limit, the lens diameter and the inter-object distance can be reduced, and thus, miniaturization of the wide-angle lens can be achieved.
Further, according to the wide-angle lens 100 of the present embodiment, when the focal length of the whole is set to f0 and the radius of curvature of the image-side lens surface of the fourth lens 140 is set to R42, the following relationship is satisfied: as shown in fig. 14A to 16G, by making R42/f0 larger than-3.000 as a lower limit, various deviations can be appropriately corrected, while by making R42/f0 smaller than-1.800 as an upper limit, the radius of curvature of the image side lens surface of the fourth lens 140 can be suppressed from becoming too small, and thus, the image side lens surface of the fourth lens 140 can be easily molded.
Further, according to the wide-angle lens 100 of the present embodiment, when the overall focal distance is set to f0 and the combined focal distance of the first lens 110, the second lens 120, and the third lens 130 is set to f123, the following relationship is satisfied: as shown in fig. 14A to 16G, by making f123/f0 larger than-4.000 as a lower limit, it is possible to avoid excessively weak optical power of the front lens group FR, thereby enabling miniaturization of the wide-angle lens, while by making f123/f0 smaller than-1.000 as an upper limit, it is possible to avoid excessively strong optical power of the front lens group FR, thereby enabling appropriate correction of various deviations, thereby achieving excellent optical performance.
Further, according to the wide-angle lens 100 of the present embodiment, when the combined focal distance of the first lens 110, the second lens 120, and the third lens 130 is set to f123, and the combined focal distance of the fourth lens 140, the fifth lens 150, and the sixth lens 160 is set to f456, the following relationship is satisfied: as shown in fig. 14A to 16G, by making f123/f456 greater than-2.500 as a lower limit, it is possible to avoid excessively weak optical power of the front lens group FR, thereby enabling miniaturization of the wide-angle lens, while by making f123/f456 smaller than-1.000 as an upper limit, it is possible to avoid excessively strong optical power of the front lens group FR, thereby enabling appropriate correction of various deviations, thereby achieving excellent optical performance.
Further, according to the wide-angle lens 100 of the present embodiment, the third lens 130 and the fourth lens 140 are both positive lenses, and therefore, negative optical powers of the first lens 110 and the second lens 120 can be enhanced, whereby lens diameters of the first lens 110 and the second lens 120 can be reduced, thereby achieving miniaturization of the lens system.
Embodiment 5
Fig. 17 is an explanatory view showing a wide-angle lens according to embodiment 5 of the present invention, fig. 18A is an explanatory view showing a field curvature of the wide-angle lens according to embodiment 5 of the present invention, fig. 18B is an explanatory view showing distortion of the wide-angle lens according to embodiment 5 of the present invention, fig. 19A is an explanatory view showing a vertical chromatic aberration (lateral chromatic aberration) of the wide-angle lens according to embodiment 5 of the present invention, fig. 19B is an explanatory view showing spherical aberration (longitudinal aberration) of the wide-angle lens according to embodiment 5 of the present invention, and fig. 20A to 20 are explanatory views showing lateral aberration of the wide-angle lens according to embodiment 5 of the present invention. Here, in fig. 18A, 18B, 19A, 19B, and 20A to 20G, a correlation curve of red light R (wavelength: 656 nm) is denoted by R, a correlation curve of green light G (wavelength: 546 nm) is denoted by G, a correlation curve of blue light B (wavelength: 486 nm) is denoted by B, a correlation with a meridian plane is denoted by T, a correlation with a sagittal plane is denoted by S, and a Maximum size of a vertical axis (Maximum Scale) is ±50.000 μm in fig. 20A to 20G.
As shown in fig. 17, the wide-angle lens 100 includes, in order from the object side (L1 side) toward the image side (L2 side), a front lens group FR composed of a first lens 110, a second lens 120, and a third lens 130 arranged in order from the object side toward the image side, an aperture stop AP, and a rear lens group RR composed of a fourth lens 140, a fifth lens 150, and a sixth lens 160 arranged in order from the object side toward the image side.
Here, since the basic structure of the wide-angle lens 1000 in the present embodiment (i.e., whether the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, and the sixth lens 160 have positive or negative optical power, whether it is a glass lens or a plastic lens, whether the object-side surface and the image-side surface are convex or concave lens surfaces, and whether they are spherical or aspherical) is the same as that of the wide-angle lens in embodiment 1, it will not be explained in detail here.
As shown in fig. 17, as in embodiment 1, a diaphragm AP (specifically, an aperture stop) is provided between the third lens 130 and the fourth lens 140, a diaphragm FD (specifically, a field stop) is provided between the fourth lens 140 and the fifth lens 150, a filter FL is disposed on the image side of the sixth lens 160, and an image pickup element SE is disposed on the image side of the filter FL. Also, the focal plane FP is shown in fig. 17.
In the present embodiment, the focal distance F (Effective Focal Length) of the entire lens system is 5.849mm, the inter-object-Image distance d (Total Track) is 33.393mm, the F-number (Image Space F/#) is 1.800, the maximum half Angle (max. Field of Angle) is 56.183 degrees, the entrance pupil diameter HEP is 3.249mm, and the distance between the object-side lens surface of the first lens 110 and the Image-side lens surface of the sixth lens 160 is 28.956mm.
Physical properties of each surface of wide-angle lens 1000 of the present embodiment are shown in table 9, and aspherical coefficients of each surface of wide-angle lens 1000 of the present embodiment are shown in tables 10-1 and 10-2.
(Table 9)
In table 9 above, the unit of the radius of curvature, thickness, focal length, and effective radius is mm, nd is the refractive index for 546 nm light, vd is abbe number, and x represents an aspherical surface.
(Table 10-1)
Flour with a plurality of grooves c (1/radius of curvature) K A4 A6
3 -8.68579E-02 0.00000E+00 2.83191E-04 -2.56796E-05
4 -3.10130E-02 0.00000E+00 8.75569E-04 -6.11635E-05
5 -9.60597E-02 0.00000E+00 1.69715E-04 -4.45772E-05
6 -1.10026E-01 0.00000E+00 1.29090E-04 -7.86617E-06
10 4.94913E-02 0.00000E+00 1.79734E-05 -8.85412E-06
11 2.00908E-01 -2.62000E+00 2.57783E-03 -8.76250E-05
12 -5.54289E-02 0.00000E+00 6.08162E-05 9.98176E-08
(Table 10-2)
Flour with a plurality of grooves A8 A10 A12 A14 A16
3 3.90082E-07 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
4 8.41896E-07 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
5 5.73085E-07 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
6 2.59118E-07 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
10 1.00575E-07 3.55790E-10 0.00000E+00 0.00000E+00 0.00000E+00
11 1.32347E-06 -3.01079E-09 0.00000E+00 0.00000E+00 0.00000E+00
12 2.77669E-08 -6.40450E-10 0.00000E+00 0.00000E+00 0.00000E+00
In tables 10-1 and 10-2 above, the radius of curvature is set to a positive value when the lens surface is a convex lens surface protruding toward the object side or a concave lens surface recessed toward the object side, and the radius of curvature is set to a negative value when the lens surface is a convex lens surface protruding toward the image side or a concave lens surface recessed toward the image side.
Table 10-1 and table 10-2 above show aspherical coefficients A4, A6, A8, a10, a12, a14, and a16 when the aspherical shape of each surface is expressed by the above equation 1.
(main effects of the present embodiment)
According to the wide-angle lens 100 of the present embodiment, the front lens group FR is composed of the first lens 110, the second lens 120, and the third lens 130 arranged in this order from the object side toward the image side, the rear lens group RR is composed of the fourth lens 140, the fifth lens 150, and the sixth lens 160 arranged in this order from the object side toward the image side, the first lens 110 is a negative lens having a concave lens surface toward the image side, the second lens 120 is a negative lens having a concave lens surface toward the object side, the third lens 130 is a lens having a concave lens surface toward the object side and a convex lens surface toward the image side, the fourth lens 140 is a glass lens having a convex lens surface toward the object side and a convex lens surface toward the image side, the fifth lens 150 is a lens having a concave lens surface toward the image side, and the sixth lens 160 is a lens having a convex lens surface toward the object side and a convex lens surface toward the image side, and therefore, it is advantageous to reduce the focal point position fluctuation due to the dimensional change in the optical axis direction at the same time.
Further, according to the wide-angle lens 100 of the present embodiment, when the radius of curvature of the object-side lens surface of the fourth lens 140 is R41 and the radius of curvature of the image-side lens surface of the fourth lens 140 is R42, the following relationship is satisfied: since 10.000 < (R41+R42)/(R41-R42) < 1.000, various deviations such as image plane curvature, chromatic aberration of magnification and coma can be appropriately corrected as shown in FIGS. 18A to 20G.
Further, according to the wide-angle lens 100 of the present embodiment, when the focal distance of the entire is set to f0 and the focal distance of the fourth lens 140 is set to f4, the following relationship is satisfied: as shown in fig. 18A to 20G, by making f4/f0 larger than 2.000 as a lower limit, as a result, excessive optical power of the fourth lens 140 can be avoided, and various deviations can be appropriately corrected, while by making f4/f0 smaller than 3.000 as an upper limit, the lens diameter and the inter-object distance can be reduced, and thus, miniaturization of the wide-angle lens can be achieved.
Further, according to the wide-angle lens 100 of the present embodiment, when the focal length of the whole is set to f0 and the radius of curvature of the image-side lens surface of the fourth lens 140 is set to R42, the following relationship is satisfied: as shown in fig. 18A to 20G, by making R42/f0 larger than-3.000 as the lower limit, various deviations can be appropriately corrected, while by making R42/f0 smaller than-1.800 as the upper limit, the radius of curvature of the image side lens surface of the fourth lens 140 can be suppressed from becoming too small, and thus, the image side lens surface of the fourth lens 140 can be easily molded.
Further, according to the wide-angle lens 100 of the present embodiment, when the overall focal distance is set to f0 and the combined focal distance of the first lens 110, the second lens 120, and the third lens 130 is set to f123, the following relationship is satisfied: as shown in fig. 18A to 20G, by making f123/f0 larger than-4.000 as a lower limit, it is possible to avoid excessively weak optical power of the front lens group FR, thereby enabling miniaturization of the wide-angle lens, while by making f123/f0 smaller than-1.000 as an upper limit, it is possible to avoid excessively strong optical power of the front lens group FR, thereby enabling appropriate correction of various deviations, thereby achieving excellent optical performance.
Further, according to the wide-angle lens 100 of the present embodiment, when the combined focal distance of the first lens 110, the second lens 120, and the third lens 130 is set to f123, and the combined focal distance of the fourth lens 140, the fifth lens 150, and the sixth lens 160 is set to f456, the following relationship is satisfied: as shown in fig. 18A to 20G, by making f123/f456 greater than-2.500 as the lower limit, it is possible to avoid excessively weak optical power of the front lens group FR, thereby enabling miniaturization of the wide-angle lens, while by making f123/f456 smaller than-1.000 as the upper limit, it is possible to avoid excessively strong optical power of the front lens group FR, thereby enabling appropriate correction of various deviations, thereby achieving excellent optical performance.
Further, according to the wide-angle lens 100 of the present embodiment, the third lens 130 and the fourth lens 140 are both positive lenses, and therefore, negative optical powers of the first lens 110 and the second lens 120 can be enhanced, whereby lens diameters of the first lens 110 and the second lens 120 can be reduced, thereby achieving miniaturization of the lens system.
The invention has been described above by way of example with reference to the accompanying drawings, it being apparent that the invention is not limited to the embodiments described above.
For example, in the above embodiment, the materials of the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, and the sixth lens 160 may be appropriately selected according to need, and may be glass or plastic.
It is to be understood that the present invention can freely combine the respective portions in the embodiment, or appropriately modify and omit the respective portions in the embodiment within the scope thereof.

Claims (8)

1. A wide-angle lens is characterized in that,
comprising a front lens group, an aperture and a rear lens group in order from an object side toward an image side,
the front lens group is composed of a first lens, a second lens and a third lens which are arranged in order from the object side toward the image side,
the rear lens group is composed of a fourth lens, a fifth lens and a sixth lens which are arranged in order from the object side toward the image side,
The first lens is a negative lens having a concave lens surface facing the image side,
the second lens is a negative lens having a concave lens surface facing the object side,
the third lens is a lens having a concave lens surface facing the object side and a convex lens surface facing the image side,
the fourth lens is a glass lens having a convex lens surface facing the object side and a convex lens surface facing the image side,
the fifth lens is a lens having a concave lens surface facing the image side,
the sixth lens is a lens having a convex lens surface facing the object side and a convex lens surface facing the image side.
2. The wide angle lens of claim 1 wherein,
when the radius of curvature of the object-side lens surface of the fourth lens is R41 and the radius of curvature of the image-side lens surface of the fourth lens is R42, the following relationship is satisfied:
10.000<(R41+R42)/(R41-R42)<1.000。
3. the wide angle lens of claim 1 wherein,
when the entire focal distance is f0 and the focal distance of the fourth lens is f4, the following relationship is satisfied:
2.000<f4/f0<3.000。
4. the wide angle lens of claim 1 wherein,
when the focal length of the entire lens is f0 and the radius of curvature of the image-side lens surface of the fourth lens is R42, the following relationship is satisfied:
-3.000<R42/f0<-1.800。
5. The wide angle lens of claim 1 wherein,
when the overall focal distance is f0 and the combined focal distance of the first lens, the second lens, and the third lens is f123, the following relationship is satisfied:
-4.000<f123/f0<-1.000。
6. the wide angle lens of claim 1 wherein,
when the combined focal distance of the first lens, the second lens, and the third lens is set to f123 and the combined focal distance of the fourth lens, the fifth lens, and the sixth lens is set to f456, the following relationship is satisfied:
-2.500<f123/f456<-1.000。
7. the wide angle lens of claim 1 wherein,
the third lens and the fourth lens are both positive lenses.
8. The wide angle lens of claim 1 wherein,
the first lens is a glass lens or a plastic lens,
the second lens, the third lens, the fifth lens, and the sixth lens are plastic lenses, respectively.
CN202210610059.7A 2022-05-31 2022-05-31 Wide angle lens Pending CN117192740A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210610059.7A CN117192740A (en) 2022-05-31 2022-05-31 Wide angle lens

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210610059.7A CN117192740A (en) 2022-05-31 2022-05-31 Wide angle lens

Publications (1)

Publication Number Publication Date
CN117192740A true CN117192740A (en) 2023-12-08

Family

ID=88996593

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210610059.7A Pending CN117192740A (en) 2022-05-31 2022-05-31 Wide angle lens

Country Status (1)

Country Link
CN (1) CN117192740A (en)

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