Imaging lens and imaging device
阅读说明：本技术 拍摄透镜以及拍摄装置 (Imaging lens and imaging device ) 是由 下枝享博 于 2018-06-28 设计创作，主要内容包括：本发明提供一种车载广角透镜,其能够同时满足测量所需要的高分辨率、可车载的尺寸以及廉价格。拍摄透镜(10)从物体侧依次具备具有负的放大率且像侧具有凹面的第1透镜(L1)、具有负的放大率且像侧具有凹面的第2透镜(L2)、具有正的放大率且物体侧具有凸面的第3透镜(L3)、光圈、具有正的放大率且像侧是凸面的第4透镜(L4)、第5透镜(L5)、物体侧与第5透镜(L5)的像侧贴合的第6透镜(L6)、具有负的放大率且像侧具有凸面的第7透镜(L7),第4透镜(L4)是非球面玻璃透镜。(The invention provides a vehicle-mounted wide-angle lens which can simultaneously meet the requirements of high resolution, vehicle-mounted size and low price required by measurement. The imaging lens (10) includes, in order from the object side, a 1 st lens (L1) having a negative power and a concave surface on the image side, a 2 nd lens (L2) having a negative power and a concave surface on the image side, a 3 rd lens (L3) having a positive power and a convex surface on the object side, a diaphragm, a 4 th lens (L4) having a positive power and a convex surface on the image side, a 5 th lens (L5), a 6 th lens (L6) bonded to the object side of the 5 th lens (L5), and a 7 th lens (L7) having a negative power and a convex surface on the image side, and the 4 th lens (L4) is an aspherical glass lens.)
1. A photographic lens is characterized in that,
the object side sequentially comprises: a 1 st lens having a negative magnification and a concave surface on an image side; a 2 nd lens having a negative magnification and a concave surface on the image side; a 3 rd lens having a positive power and a convex surface on the object side; an aperture; a 4 th lens element having a positive power and having a convex image side; a 5 th lens; a 6 th lens having an object side bonded to the image side of the 5 th lens; and a 7 th lens having a negative magnification and a convex surface on the image side,
the 4 th lens is an aspherical glass lens.
2. The taking lens according to claim 1,
among the lenses having positive power from the 1 st lens to the 7 th lens, the 4 th lens has the largest power.
3. The photographing lens according to claim 1 or 2,
when the focal length of the 4 th lens is defined as f4 and the focal length of the entire lens optical system is defined as f, the following formula (2) is satisfied,
2.8＜f4/f＜3.5 (2)。
4. the taking lens according to any one of claims 1 to 3,
when the focal length of the 5 th lens is defined as f5 and the focal length of the entire lens optical system is defined as f, the following formula (1) is satisfied,
-3.0＜f5/f＜-2.2 (1)。
5. the taking lens according to any one of claims 1 to 4,
the image side of the 5 th lens and the object side of the 6 th lens are aspheric.
6. The taking lens according to any one of claims 1 to 5,
the 2 nd lens, the 3 rd lens, the 5 th lens, the 6 th lens, and the 7 th lens are plastic lenses.
7. A camera device is characterized in that a camera body is provided,
the disclosed device is provided with:
the photographing lens system according to any one of claims 1 to 6;
a flat plate-like cover glass disposed on the object side of the imaging lens system; and
and an imaging element disposed at a focal position of the imaging lens system.
Technical Field
The invention relates to an imaging lens and an imaging device.
Background
In recent years, the use of wide-angle lenses mounted on automobiles has changed from observation to measurement. In the measurement, a resolution required for image analysis is required, and therefore, a high-resolution image corresponding to a megapixel is required. In addition, in the vehicle-mounted wide-angle lens, attention is also paid to a performance change due to temperature. For example, patent document 1 describes a wide-angle lens for vehicle mounting.
On the other hand, a small-sized and inexpensive wide-angle lens is also required for the on-vehicle wide-angle lens. Thus, a market demand for a vehicle-mounted wide-angle lens having high performance, small size, and low cost is generated.
Disclosure of Invention
Problems to be solved by the invention
However, in the vehicle-mounted wide-angle lens, a glass lens is generally used when high resolution and performance improvement due to high temperature are required, and there is a problem that the camera has a large-sized structure and is expensive. As such, a vehicle-mounted wide-angle lens that satisfies the high resolution, the vehicle-mountable size, and the low price required for the measurement at the same time cannot be realized.
Means for solving the problems
The imaging lens system according to one embodiment includes, in order from an object side, a 1 st lens having a negative power and a concave surface on an image side, a 2 nd lens having a negative power and a concave surface on an image side, a 3 rd lens having a positive power and a convex surface on an object side, a stop, a 4 th lens having a positive power and a convex surface on an image side, a 5 th lens, a 6 th lens having an object side bonded to the image side of the 5 th lens, and a 7 th lens having a negative power and a convex surface on an image side, and the 4 th lens is an aspheric glass lens.
Preferably, in the photographing lens system according to an embodiment, the magnification of the 4 th lens is the largest among lenses having positive magnifications from the 1 st lens to the 7 th lens.
Preferably, the imaging lens system according to one embodiment satisfies the following expression (2) when the focal length of the 4 th lens is defined as f4 and the focal length of the entire lens optical system is defined as f.
2.8＜f4/f＜3.5 (2)
Preferably, the imaging lens system according to one embodiment satisfies the following expression (1) when the focal length of the 5 th lens is defined as f5 and the focal length of the entire lens optical system is defined as f.
-3.0＜f5/f＜-2.2 (1)
Preferably, the image side of the 5 th lens and the object side of the 6 th lens of the photographing lens system according to an embodiment are aspheric.
Preferably, the 2 nd lens, the 3 rd lens, the 5 th lens, the 6 th lens, and the 7 th lens of the imaging lens system according to an embodiment are plastic lenses.
An imaging device according to an embodiment includes the imaging lens system described in any one of the above, a lens barrel that holds the imaging lens system, a flat plate-like cover glass that is arranged on an object side of the imaging lens system, and an imaging element that is arranged at a focal position of the imaging lens system.
Effects of the invention
According to the vehicle-mounted wide-angle lens and the shooting device, high resolution, vehicle-mounted size and low cost required by measurement can be met simultaneously.
Drawings
Fig. 1 is a sectional view of a photographing lens system of embodiment 1.
Fig. 2A is a longitudinal aberration diagram in the photographing lens system of embodiment 1.
Fig. 2B is an image plane curvature diagram in the photographing lens system of embodiment 1.
Fig. 2C is a distortion correction diagram in the photographing lens system of example 1.
Fig. 3 is a sectional view of a taking lens system of embodiment 2.
Fig. 4A is a longitudinal aberration diagram in the photographing lens system of embodiment 2.
Fig. 4B is an image plane curvature diagram in the photographing lens system of embodiment 2.
Fig. 4C is a distortion correction diagram in the photographing lens system of example 2.
Fig. 5 is a sectional view of a taking lens system of embodiment 3.
Fig. 6A is a longitudinal aberration diagram in the photographing lens system of embodiment 3.
Fig. 6B is an image plane curvature diagram in the photographing lens system of embodiment 3.
Fig. 6C is a distortion correction diagram in the photographing lens system of example 3.
Fig. 7 is a sectional view of a taking lens system of embodiment 4.
Fig. 8A is a longitudinal aberration diagram in the photographing lens system of embodiment 4.
Fig. 8B is an image plane curvature diagram in the photographing lens system of embodiment 4.
Fig. 8C is a distortion correction diagram in the photographing lens system of example 4.
Fig. 9 is a sectional view in a taking lens system of embodiment 5.
Fig. 10A is a longitudinal aberration diagram in the photographing lens system of embodiment 5.
Fig. 10B is an image plane curvature diagram in the photographing lens system of embodiment 5.
Fig. 10C is a distortion correction diagram in the imaging lens system of example 5.
Fig. 11 is a sectional view of the imaging apparatus according to embodiment 6.
Detailed Description
The following describes the imaging lens system and the imaging apparatus according to the present embodiment.
(embodiment 1: photographic lens System)
Fig. 1 is a sectional view of a photographing lens system of embodiment 1. In fig. 1, the photographing lens system 11 includes, in order from the object side, a 1 st lens L1 having a negative magnification and a concave surface on the image side, a 2 nd lens L2 having a negative magnification and a concave surface on the image side, a 3 rd lens L3 having a positive magnification and a convex surface on the object side, a STOP, a 4 th lens L4 having a positive magnification and a convex surface on the image side, a 5 th lens L5, a 6 th lens L6 attached to the object side of the 5 th lens, and a 7 th lens L7 having a negative magnification and a convex surface on the image side. The imaging lens system 11 is provided with an IR cut filter 12. In addition, the IMG denotes an imaging plane.
The 1 st lens L1 is a lens having a negative power. The object side lens surface S1 of the 1 st lens L1 includes a convex curved surface portion protruding toward the object side. The image side lens surface S includes a concave curved surface portion that is concave toward the object side. The 1 st lens L1 is preferably made of polished glass.
The 2 nd lens L2 is an aspherical lens having a negative power. The object side lens surface image S4 of the 2 nd lens L2 includes a convex curved surface portion protruding toward the object side, and the image side lens surface S5 includes a concave curved surface portion recessed toward the object side. The 2 nd lens L2 is preferably formed of a plastic lens.
The 3 rd lens L3 is an aspherical lens having a positive power. The object side lens surface S6 of the 3 rd lens L3 includes a convex curved surface portion protruding toward the object side, and the image side lens surface S7 includes a convex curved surface portion protruding toward the image side. The 3 rd lens L3 is preferably formed of a plastic lens.
The STOP adjusts the amount of light passing through. For example, it is suitable that the STOP has a plate shape having an aperture.
The 4 th lens L4 is an aspherical lens having a positive power. The object-side lens surface S9 of the 4 th lens L4 includes a concave curved surface portion that is concave toward the image side, and the image-side lens surface S10 includes a convex curved surface portion that is convex toward the image side. The 4 th lens L4 is preferably formed of an aspherical glass lens.
The 5 th lens L5 is an aspherical lens having a negative power. The object-side lens surface S11 of the 5 th lens L5 includes a convex curved surface portion protruding toward the object side, and the image-side lens surface S12 includes a concave curved surface portion recessed toward the object side. The 5 th lens L5 is preferably formed of a plastic lens.
The 6 th lens L6 is an aspherical lens having a positive power. The object side lens surface S13 of the 6 th lens L6 includes a convex curved surface portion protruding toward the object side, and the image side lens surface S14 includes a convex curved surface portion protruding toward the image side. The 6 th lens L6 is preferably formed of a plastic lens.
The image side lens surface of the 5 th lens L5 and the object side lens surface of the 6 th lens L6 are bonded to each other with an ultraviolet curable adhesive, and a bonded lens is formed by the 5 th lens L5 and the 6 th lens L6. The distance between the image side lens surface of the 5 th lens L5 and the object side lens surface of the 6 th lens L6 gradually increases from the optical axis toward the outer peripheral surface, and bubbles in the adhesive easily overflow to the outside. The combined magnification of the 5 th lens L5 and the 6 th lens L6 is a positive magnification.
The 7 th lens L7 is an aspherical lens having a negative power. The object-side lens surface S15 of the 7 th lens L7 includes a concave curved surface portion that is concave toward the image side, and the image-side lens surface S16 includes a convex curved surface portion that is convex toward the image side. The 7 th lens L7 is preferably formed of a plastic lens.
The IR cut filter 12 is a filter for cutting off infrared rays.
Hereinafter, the characteristic data of the photographing lens system 11 will be described.
First, table 1 shows lens data of each lens surface of the photographing lens system 11. Table 1 shows lens data of each lens surface of the photographing lens system 11. The curvature radius, surface interval, refractive index, and abbe number of each surface are shown in table 1 as lens data. The surface marked with a "+" sign "is denoted as an aspherical surface.
[ Table 1]
Lens parameters
The aspherical shape adopted by the lens surface is expressed by the following equation, where Z is a sag, c is a reciprocal of a curvature radius, k is a conical coefficient, and r is a ray height from the optical axis Z, and aspherical coefficients of 4, 6, 8, 10, 12, 14, and 16 times are α 4, α 6, α 8, α 10, α 12, α 14, and α 16, respectively.
[ number 1]
Table 2 shows aspheric coefficients for defining an aspheric shape of a lens surface to be an aspheric surface in the photographing lens system 11 of example 1. In Table 2, for example "-6.522528E-03" means "-6.522528X 10-3”。
[ Table 2]
Coefficient of aspheric surface
No. 3 surface
No. 4 surface
The 5 th plane
The 6 th plane
The 9 th plane
The 10 th side
k
0.000000E+00
-0.584698029
0
0.000000E+00
0.000000E+00
-0.014941829
α4
-3.212063E-03
1.537786E-03
5.007120E-03
8.551597E-03
-8.173230E-03
5.043637E-03
α6
9.514080E-05
-1.067514E-03
-2.332544E-04
-2.371804E-03
-1.237787E-03
-3.462408E-04
α8
-1.138907E-06
3.593001E-06
1.323046E-04
1.184827E-03
-1.891273E-04
5.526840E-05
α10
-1.865120E-08
0.000000E+00
0.000000E+00
-1.454256E-04
0.000000E+00
0.000000E+00
α12
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
α12
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
α16
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
The 11 th plane
The 12 th surface
The 13 th side
The 14 th side
The 15 th surface
The 16 th surface
k
0
-2.095437E-01
-2.095437E-01
0
0.000000E+00
0
α4
2.779169E-03
6.975202E-03
9.975202E-03
2.363654E-02
1.150292E-02
-1.331737E-02
α6
1.548943E-04
1.125342E-04
1.125342E-04
-4.434208E-03
-2.329412E-03
3.993663E-03
α8
0.000000E+00
-1.626998E-04
-1.626998E-04
6.404750E-04
5.690953E-05
-9.674284E-04
α10
0.000000E+00
0.000000E+00
0.000000E+00
-2.956144E-05
0.000000E+00
9.632779E-05
α12
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
-3.320306E-06
α12
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
6.930747E-09
α16
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
0.000000E+00
Fig. 2A is a longitudinal aberration diagram in the photographing lens system of embodiment 1. Fig. 2B is an image plane curvature diagram in the photographing lens system of embodiment 1. Fig. 2C is a distortion correction diagram in the photographing lens system of example 1. As shown in fig. 2A to 2C, in the photographing lens system 11 of example 1, the half angle of view is 99 °, and the F value is 2.0. In the vertical convergence diagram of fig. 2A, the horizontal axis represents the position where the light ray intersects the optical axis Z, and the vertical axis represents the height in the pupil diameter.
In the field curvature diagram of fig. 2B, the horizontal axis represents the distance in the optical axis Z direction, and the vertical axis represents the image height (field angle). In the field curvature diagram of fig. 2B, Sag represents field curvature in the radial plane, and Tan represents field curvature in the tangential plane. As shown in the field curvature diagram of fig. 2B, according to the photographing lens system 11 of the present embodiment, field curvature can be corrected well. Therefore, the photographing lens system 11 is high-resolution.
In the distortion correction map of fig. 2C, the horizontal axis represents the amount of distortion (%) of the image, and the vertical axis represents the image height (angle of view). The results of simulation with light having a wavelength of 588nm are shown in the image plane curvature diagram of FIG. 2B and the distortion collection diagram of FIG. 2C.
Next, table 3 shows the results of calculating the characteristic values of the imaging lens system 11 of example 1. Table 3 shows that f is the focal length of the entire lens system and f is the focal length of the 1 st lens L1 in the photographing lens system 111F is the focal length of the 2 nd lens L22F is the focal length of the 3 rd lens L33F is the focal length of the 4 th lens L44F is the focal length of the 5 th lens L55F is the focal length of the 6 th lens L66F is the focal length of the 7 th lens L77Characteristic values of these (combined focal length f of the 1 st lens L1 and the 2 nd lens L2)12And a combined focal length f of the 2 nd lens and the 3 rd lens L323And a combined focal length f of the 3 rd lens L3 and the 4 th lens L434And a combined focal length f of the 4 th lens L4 and the 5 th lens L545And a combined focal length f between the 5 th lens L5 and the 6 th lens L656And a combined focal length f between the 6 th lens L6 and the 7 th lens L767)、f4F and f5And/f. The various focal distances were calculated using light at 588nm wavelength.
[ Table 3]
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