JP6836211B2 - Imaging optical system, lens unit, and imaging device - Google Patents

Description

The present invention relates to an image pickup optical system, a lens unit, and an image pickup apparatus for, for example, in-vehicle use and surveillance use.

In recent years, there has been a demand for an imaging optical system, particularly an in-vehicle optical system, which is compact, has high resolution, has a wide angle, and has a bright F number, which can withstand sensing applications such as automatic driving. Patent Document 1 discloses an optical system having seven lenses and an angle of view of about 180 °.

The optical system in Patent Document 1 has dimensions and an angle of view suitable for automobiles, but has an optical performance such as a dark F number of 2.8 and insufficient contrast around the screen due to chromatic aberration and coma. Is inadequate.

Japanese Unexamined Patent Publication No. 2014-102291

In view of the above circumstances, it is an object of the present invention to provide an imaging optical system which is compact, has an angle of view of 180 ° or more, is bright as about F2, and has various aberrations satisfactorily corrected.

Another object of the present invention is to provide a lens unit and an imaging device provided with the above-mentioned imaging optical system.

In order to achieve at least one of the above-mentioned objects, the imaging optical system reflecting one aspect of the present invention is, in order from the object side, a first lens having a negative refractive power and a first lens having a negative refractive power. A first lens group consisting of two lenses, a third lens having a positive refractive power, and a fourth lens having a positive refractive power, an aperture aperture, and a fifth lens having a positive refractive power. a sixth lens having negative refractive power, a second lens group consisting essentially seventh lens having a positive refractive power and a meniscus shape fourth lens having a concave surface on the object side have a, satisfy the following conditional expression.
8 ≦ f4 / f ≦ 15… (1)
However, the value f4 is the focal length of the fourth lens, and the value f is the focal length of the entire lens system.

Further, the lens unit reflecting one aspect of the present invention includes the above-mentioned imaging optical system and a lens barrel that holds the imaging optical system.

Further, the image pickup apparatus reflecting one aspect of the present invention includes the above-mentioned image pickup optical system and an image pickup element for detecting an image obtained from the image pickup optical system.

It is a figure explaining the lens unit and the image pickup apparatus which include the image pickup optical system of one Embodiment of this invention. FIG. 2A is a cross-sectional view showing the imaging optical system of the first embodiment, and FIGS. 2B and 2C are aberration diagrams. FIG. 3A is a cross-sectional view showing the imaging optical system and the like of the second embodiment, and FIGS. 3B and 3C are aberration diagrams. 4A is a cross-sectional view showing the imaging optical system and the like of the third embodiment, and FIGS. 4B and 4C are aberration diagrams. 5A is a cross-sectional view showing the imaging optical system and the like of Example 4, and FIGS. 5B and 5C are aberration diagrams. FIG. 6A is a cross-sectional view showing the imaging optical system of Example 5, and FIGS. 6B and 6C are aberration diagrams. FIG. 7A is a cross-sectional view showing the imaging optical system of Example 6, and FIGS. 7B and 7C are aberration diagrams. 8A is a cross-sectional view showing the imaging optical system and the like of Example 7, and FIGS. 8B and 8C are aberration diagrams. 9A is a cross-sectional view showing the imaging optical system and the like of Example 8, and FIGS. 9B and 9C are aberration diagrams.

FIG. 1 is a cross-sectional view showing an image pickup apparatus 100 according to an embodiment of the present invention. The image pickup device 100 includes a camera module 30 for forming an image signal, and a processing unit 60 that exerts a function as the image pickup device 100 by operating the camera module 30.

The camera module 30 includes a lens unit 40 having a built-in imaging optical system 10 and a sensor unit 50 that converts a subject image formed by the imaging optical system 10 into an image signal.

The lens unit 40 includes an imaging optical system 10 which is a wide-angle optical system, and a lens barrel 41 incorporating the imaging optical system 10. The imaging optical system 10 is composed of the first to seventh lenses L1 to L7. The lens barrel 41 is made of resin, metal, a mixture of resin and glass fiber, or the like, and houses and holds a lens or the like inside. When the lens barrel 41 is formed of a metal or a resin mixed with glass fiber, it is less likely to expand thermally than the resin, and the imaging optical system 10 can be stably fixed. The lens barrel 41 has an opening OP for incident light from the object side.

The total angle of view of the imaging optical system 10 is 180 ° or more. The first to seventh lenses L1 to L7 constituting the imaging optical system 10 are directly or indirectly held on the inner surface side of the lens barrel 41 at their flanges or outer peripheral portions, and are directly or indirectly held in the optical axis AX direction and light. Positioning is done in the direction perpendicular to the axis AX.

The sensor unit 50 includes an image pickup element (solid-state image pickup element) 51 that photoelectrically converts a subject image formed by the image pickup optical system (wide-angle optical system) 10, and a substrate 52 that supports the image pickup element 51. The image sensor 51 is, for example, a CMOS type image sensor. The substrate 52 includes wiring, peripheral circuits, and the like for operating the image pickup device 51. The image sensor 51 and the like are positioned and fixed with respect to the optical axis AX by a holder member (not shown). This holder member is fixed in a positioned state so as to fit into the lens barrel 41 of the lens unit 40.

The image sensor 51 has a photoelectric conversion unit 51a provided with an image pickup surface I, and a signal processing circuit (not shown) is formed around the photoelectric conversion unit 51a. Pixels, that is, photoelectric conversion elements are two-dimensionally arranged in the photoelectric conversion unit 51a. The image sensor 51 is not limited to the above-mentioned CMOS type image sensor, and may incorporate another image sensor such as a CCD.

A filter F or the like can be arranged between the lenses constituting the lens unit 40 or between the lens unit 40 and the sensor unit 50. In the example of FIG. 1, the filter F is arranged between the seventh lens L7 of the image pickup optical system 10 and the image pickup element 51. The filter F is a parallel flat plate assuming an optical low-pass filter, an IR cut filter, a seal glass of the image sensor 51, and the like. The filter F can be arranged as a separate filter member, but it is not arranged as a separate body, and the function can be imparted to any lens surface constituting the imaging optical system 10. For example, in the case of an infrared cut filter, an infrared cut coat may be applied on the surface (optical surface) of one or a plurality of lenses.

The processing unit 60 includes an element driving unit 61, an input unit 62, a storage unit 63, a display unit 64, and a control unit 68. The element drive unit 61 outputs a YUV or other digital pixel signal to an external circuit (specifically, a circuit attached to the image sensor 51 or the like), or drives a voltage or clock signal from the control unit 68 to drive the image sensor 51. The image sensor 51 is operated by receiving the supply of the image sensor 51. The input unit 62 is a part that receives a user's operation or a command from an external device, and the storage unit 63 is a part that stores information necessary for the operation of the image pickup device 100, image data acquired by the camera module 30, and the like. Yes, the display unit 64 is a portion that displays information to be presented to the user, a captured image, and the like. The control unit 68 comprehensively controls the operations of the element drive unit 61, the input unit 62, the storage unit 63, and the like, and can perform various image processing on the image data obtained by the camera module 30, for example. ..

Although detailed description is omitted, the specific function of the processing unit 60 is appropriately adjusted according to the application of the device in which the image pickup apparatus 100 is incorporated. The image pickup device 100 can be mounted on devices for various purposes such as an in-vehicle camera and a surveillance camera.

Hereinafter, the imaging optical system (wide-angle optical system) 10 and the like of the first embodiment will be described with reference to FIG. The imaging optical system 10 illustrated in FIG. 1 has substantially the same configuration as the imaging optical system 10A of the first embodiment described later.

The illustrated imaging optical system (wide-angle optical system) 10 includes a first lens group Gr1, an aperture diaphragm ST, and a second lens group Gr2 in order from the object side. The first lens group Gr1 includes a first lens L1 having a negative refractive power, a second lens L2 having a negative refractive power, a third lens L3 having a positive refractive power, and positive lenses in this order from the object side. It becomes substantially from the fourth lens L4 having an optical power. The second lens group Gr2 is substantially composed of a fifth lens L5 having a positive refractive power, a sixth lens L6 having a negative refractive power, and a seventh lens L7 having a positive refractive power in order from the object side. become. In the above, the fourth lens L4 has a meniscus shape with a concave surface facing the object side.

Further, the sixth lens L6 has a biconcave shape. As a result, the negative refractive power is not concentrated too much on one side as compared with the case where only one side has a negative refractive power as in the case of a negative meniscus lens, and non-point aberration and lateral chromatic aberration generated in the sixth lens L6 are suppressed. At the same time, since sufficient negative refractive power can be obtained on both sides of the sixth lens L6, spherical aberration, coma aberration, and axial aberration generated by the positive fifth lens L5 and the positive seventh lens L7 before and after the force can be obtained. , And non-point aberration and chromatic aberration of magnification can be satisfactorily corrected.

Further, the object side surface of the second lens L2 has a concave shape on the object side in the vicinity of the optical axis AX, and is located on the image side of the surface apex at the effective diameter position. In this case, by making the shape of the region near the optical axis AX concave on the side surface of the object of the second lens L2, the angle of incidence of the axial light beam on the lens surface can be reduced, so that the light beam is generated by the axial light beam. Spherical aberration can be suppressed. Further, by locating the side surface of the object of the second lens L2 at the effective diameter position on the image side of the surface apex, the side surface of the object can be formed into a convex shape in a region outside the region near the optical axis AX, and thus is incident on this region. The incident angle of the off-axis light rays can be suppressed, and the coma aberration and the like generated by the second lens L2 can be reduced.

The imaging optical system (wide-angle optical system) 10 satisfies the following conditional expression (1).
8 ≦ f4 / f ≦ 15… (1)
However, the value f4 is the focal length of the fourth lens L4, and the value f is the focal length of the entire lens system.

By setting the value f4 / f of the conditional expression (1) to the lower limit value or more, the refractive power of the fourth lens L4 does not become too strong, and the occurrence of spherical aberration, coma aberration, and axial aberration and error sensitivity can be suppressed. .. On the other hand, by setting the value to or less than the upper limit of the conditional expression (1), it is possible to prevent the imaging optical system 10 from becoming large. That is, miniaturization can be maintained.

Further, the imaging optical system 10 further satisfies the following conditional expression (2).
1.9 ≤ d23 / f ≤ 3 ... (2)
However, the value d23 is the air distance between the second lens L2 and the third lens L3 on the optical axis AX.

By setting the value d23 / f of the conditional expression (2) to the lower limit value or more, the second lens L2 and the third lens L3 do not come too close to each other, and the refractive powers strengthen each other to generate astigmatism and chromatic aberration of magnification. It is possible to prevent the lens from becoming large and the lenses from interfering with each other. On the other hand, by setting the value to or less than the upper limit of the conditional expression (2), it is possible to prevent the overall length of the imaging optical system 10 and the diameter of the front lens from becoming large.

Further, the imaging optical system 10 further satisfies the following conditional expression (3).
0.3 ≤ d34 / f ≤ 0.8 ... (3)
However, the value d34 is the air distance between the third lens L3 and the fourth lens L4 on the optical axis AX.

By setting the value d34 / f of the conditional expression (3) to the lower limit value or more, the third lens L3 and the fourth lens L4 do not come too close to each other, and the refractive powers of the third lens L3 and the fourth lens L4 are strengthened to strengthen spherical aberration, coma aberration, and axial chromatic aberration. It is possible to prevent the amount of chromatic aberration generated, the aberration sensitivity from becoming large, and the lenses from interfering with each other. On the other hand, by setting the value to or less than the upper limit of the conditional expression (3), it is possible to prevent the overall length of the imaging optical system 10 and the diameter of the front lens from becoming large.

Further, the imaging optical system 10 further satisfies the following conditional expression (4).
0.2 ≦ d67 / f ≦ 0.4… (4)
However, the value d67 is the air distance between the sixth lens L6 and the seventh lens L7 on the optical axis AX.

By setting the value d67 / f of the conditional expression (4) to the lower limit value or more, the sixth lens L6 and the seventh lens L7 do not come too close to each other, and the refractive powers strengthen each other to generate astigmatism and chromatic aberration of magnification. It is possible to prevent the lens from becoming large and the lenses from interfering with each other. On the other hand, by setting the value to or less than the upper limit of the conditional expression (4), it is possible to prevent the overall length of the imaging optical system 10 and the diameter of the front lens from becoming large.

Further, the imaging optical system 10 further satisfies the following conditional expression (5).
0.5 ≤ f1 / f2 ≤ 5 ... (5)
However, the value f1 is the focal length of the first lens L1, and the value f2 is the focal length of the second lens L2.

By setting the value f1 / f2 of the conditional expression (5) to the lower limit value or more, the refractive power of the first lens L1 does not become too strong with respect to the refractive power of the second lens L2, and the burden on the first lens L1 is reduced. Therefore, astigmatism and chromatic aberration of magnification generated by the first lens L1 can be reduced, and the error sensitivity of the first lens L1 can be suppressed. On the other hand, by setting the value to the upper limit of the conditional expression (5) or less, the refractive power of the second lens L2 does not become too strong with respect to the refractive power of the first lens L1, and the burden on the second lens L2 is reduced. Astigmatism and chromatic aberration of magnification generated by the two lens L2 can be reduced, and the error sensitivity of the second lens L2 can be suppressed.

Further, the imaging optical system 10 further satisfies the following conditional expression (6).
-12 ≤ (r4i + r4o) / (r4i-r4o) <-1 ... (6)
However, the value r4i is the radius of curvature of the image side surface of the fourth lens L4, and the value r4o is the radius of curvature of the object side surface of the fourth lens L4.

By setting the value (r4i + r4o) / (r4i-r4o) of the conditional expression (6) to the lower limit value or more, the front main point position of the fourth lens L4 is not too close to the third lens L3 side, and the fourth lens L4 Since the combined refractive power of the third lens L3 and the fourth lens L4 can be strongly maintained without making the refractive power excessively strong, imaging optics can be suppressed while suppressing aberration generation and error sensitivity in the fourth lens L4. The miniaturization of the system 10 can be achieved. On the other hand, by falling below the upper limit of the conditional expression (6), the curvature of the side surface of the object of the fourth lens L4 is not made too large, and the performance deteriorates due to spherical aberration, coma, etc. generated on this surface and eccentricity error. And can be suppressed.

Further, the imaging optical system 10 further satisfies the following conditional expression (7).
-12 ≤ (r4i + r4o) / (r4i-r4o) ≤ -1.5 ... (7)

By satisfying the range of the conditional expression (7), the effect of suppressing the spherical aberration and coma aberration generated on the side surface of the object of the fourth lens L4 and the performance deterioration due to the eccentricity error is further enhanced.

Further, the imaging optical system 10 further satisfies the following conditional expression (8).
2 ≦ f7 / f ≦ 4 ... (8)
However, the value f7 is the focal length of the seventh lens L7.

By setting the value f7 / f of the conditional expression (8) to the lower limit value or more, the refractive power of the 7th lens L7 does not become too strong, and the chromatic aberration of magnification generated in the 7th lens L7 and the performance fluctuation due to the eccentricity error can be determined. It can be suppressed. On the other hand, by setting the value to the upper limit of the conditional expression (8) or less, the refractive power of the seventh lens L7 does not become too weak, the miniaturization of the imaging optical system 10 is maintained, and the angle of light incident on the image sensor is suppressed. Can be done.

Further, the imaging optical system 10 further satisfies the following conditional expression (9).
-6 ≤ f6 / f ≤ -2 ... (9)
However, the value f6 is the focal length of the sixth lens L6.

By setting the value f6 / f of the conditional expression (9) to the lower limit value or more, the refractive power of the sixth lens L6 does not become too weak, and the positive fifth lens L5 and the positive seventh lens L7 before and after that do not become too weak. A sufficient refractive power can be obtained to satisfactorily correct spherical aberration, coma, axial chromatic aberration, astigmatism, and lateral chromatic aberration generated in the lens. Further, the miniaturization of the imaging optical system 10 can be maintained. On the other hand, when the value is equal to or less than the upper limit of the conditional expression (9), the refractive power of the sixth lens L6 does not become too strong, and astigmatism, chromatic aberration of magnification, and performance fluctuation due to eccentricity error generated in the sixth lens L6 Can be suppressed.

Further, out of the four lenses of the first lens group Gr1, three lenses are made of plastic (or resin lens). In the case of the example of FIG. 1, the second to fourth lenses L2 to L4 are plastic lenses. Further, the second lens group Gr2 has one lens having a positive refractive power made of plastic (or a resin lens) and one lens having a negative refractive power made of plastic (or a resin lens). .. In the case of the example of FIG. 1, the sixth and seventh lenses L6 and L7 are plastic lenses. In this case, the imaging optical system 10 further satisfies the following conditional expression (10).
−0.32 ≦ f × Σ (1 / fplk) ≦ 0.32… (10)
However, the value fplk is the focal length of the kth (k is a natural number) plastic lens from the object side.

In the first lens group Gr1, the weight of the imaging optical system 10 can be reduced by using three plastic lenses. Further, an aspherical surface can be added by injection molding or the like, the degree of freedom in shape is increased as compared with the spherical surface, and spherical aberration, coma aberration and the like can be satisfactorily corrected. Furthermore, sufficient degrees of freedom can be obtained to offset focus shifts and aberration fluctuations when the temperature changes. In addition, by using a plastic lens for the second lens group Gr2, it is possible to achieve weight reduction and secure optical performance due to the aspherical surface, as in the case of the first lens group Gr1, and offset the focus shift and aberration fluctuation during temperature changes. You have enough freedom to do it. The conditional equation (10) is an equation obtained by summing the powers (refractive powers) of the plastic lenses in the imaging optical system 10 and multiplying the focal lengths of the entire imaging optical system 10. When using a plastic lens, if the power of the plastic lens is not set appropriately, the amount of focus movement and the amount of change in aberration when the temperature changes will be large, and the imaging position will change significantly and the performance will be large. It deteriorates. Therefore, in order to suppress focus movement and aberration fluctuation due to temperature change, it is preferable that the combined powers of the positive plastic lens and the negative plastic lens cancel each other out, and it is necessary to reduce the difference. By setting the value f × Σ (1 / fplk) of the conditional expression (10) to the upper limit or less, it is possible to suppress an increase in back focus due to the positive combined power becoming too strong when the temperature changes to the high temperature side. Can be done. Further, by setting the value to the upper limit value or less of the conditional expression (10), it is possible to suppress a decrease in back focus due to the positive combined power becoming too strong when the temperature changes to the low temperature side. On the other hand, by setting the condition value to the lower limit value or more of the conditional expression (10), it is possible to suppress a decrease in back focus due to the negative combined power becoming too strong when the temperature changes to the high temperature side. Further, by setting the condition value to the lower limit value or more of the conditional expression (10), it is possible to suppress an increase in back focus due to the negative combined power becoming too strong when the temperature changes to the low temperature side.

The imaging optical system 10 may further include other optical elements (for example, a lens, a filter member, etc.) having substantially no power.

In the imaging optical system 10 and the like described above, regarding setting the lens configuration of the first lens group Gr1 which is the object side group from the aperture diaphragm ST to negative and negative positive and negative, first, the first and second lenses L1 and L2 are negative. By making it negative, the entrance pupil can be arranged on the object side, so that the back focus can be secured even if the front lens has a small diameter and the focal length is short, and the installation space for filters and the like can be secured. By using two negative lenses instead of one, the refractive power can be divided to ensure good performance and suppress error sensitivity. Further, the positive and negative aberrations of the first and second lenses L1 and L2 can be canceled by the positive and negative of the third and fourth lenses L3 and L4. By changing the number of lenses from one to two, the refractive power can be divided to ensure good performance and suppress error sensitivity. In this way, by setting the lens configuration of the object side group from the aperture stop ST to negative, negative, positive and positive, the front lens diameter is small despite the wide angle, and while ensuring the back focus, aberration correction in the object side group from the aperture stop ST Can be done well. Further, good aberration correction can be performed by setting the lens configuration of the second lens group Gr2, which is the image side group from the aperture diaphragm ST, to a so-called triplet of positive and negative positive. In this way, by providing the aperture aperture ST between the fourth lens L4 and the fifth lens L5, both the first lens group Gr1 on the object side and the second lens group Gr2 on the image side of the aperture aperture ST have spherical aberration. , Aberrations such as coma aberration, non-point aberration, and chromatic aberration can be suppressed to a small value, and good optical performance can be obtained in the entire optical system. Further, by turning the concave surface of the fourth lens L4 immediately before the aperture stop ST toward the object side, the front principal point can be arranged on the image side, and the distance between the principal points and the third lens L3 can be widened. As a result, the combined refractive power with the third lens L3 can be increased while reducing the refractive power of the fourth lens L4, so that the first lens group Gr1 can be miniaturized while suppressing the occurrence of aberration in the fourth lens L4. As a result, the entire optical system can be miniaturized.

Although the lens unit 40 and the imaging device 10 incorporating the above imaging optical system 10 are compact, they have an angle of view of 180 ° or more, are bright as about F2, and enable imaging in a state in which various aberrations are well corrected. To do.

ただし、
Ａｉ：ｉ次の非球面係数
Ｒ ：基準曲率半径
Ｋ ：円錐定数〔Example〕
Hereinafter, examples of the imaging optical system and the like of the present invention will be shown. The symbols used in each embodiment are as follows.
f: Focal length of the entire imaging optical system Fno: F number w: Half angle of view ymax: Maximum image height TL: Total length of lens (total length of optical) (distance on the optical axis from the lens surface on the most object side to the imaging surface)
BF: Back focus PDΔ + 100: Focus movement amount due to temperature change of plastic lens from normal temperature (20 ° C) to 100 ° C high temperature PDΔ-65: Focus movement amount due to temperature change of plastic lens from normal temperature (20 ° C) to 65 ° C low temperature R: Radius of curvature D: Shaft top spacing nd: Refractive coefficient of lens material with respect to d line vd: Abbe number of lens material In each embodiment, the surface in which "*" is described after each surface number has an aspherical shape. The shape of the aspherical surface is represented by the following "Equation 1" with the aspherical surface as the origin, the X-axis in the optical axis direction, and the height in the direction perpendicular to the optical axis as h.

However,
Ai: i-order aspherical coefficient R: reference radius of curvature K: conical constant

(Example 1)
The overall specifications of the imaging optical system of Example 1 are shown below.
f: 0.80 (mm)
Fno: 2.00
w: 100.0 (°)
ymax: 1.78 (mm)
TL: 16.72 (mm)
BF: 1.76 (mm)
PDΔ + 00: 00.010 (mm)
PDΔ-65: -0.007 (mm)

The data of the lens surface of the imaging optical system of Example 1 is shown in Table 1 below. In Table 1 and the like below, the surface number is represented by "Surf. N", the aperture stop is represented by "ST", and infinity is represented by "INF". Further, "image" represents the imaging surface I (or the imaging surface of the imaging optical system) of the image pickup device.
[Table 1]
Surf. NR (mm) D (mm) nd vd
1 20.057 1.44 1.79085 46.3
2 4.814 3.50
3 * -3.899 0.70 1.54438 55.9
4 * 2.581 1.63
5 * 4.693 1.38 1.63469 23.9
6 * -9.569 0.62
7 * -2.603 1.47 1.54438 55.9
8 * -2.197 0.23
9 ST INF 0.30
10 10.548 1.56 1.72916 54.7
11 -2.279 0.10
12 * -2.723 0.50 1.63469 23.9
13 * 3.194 0.17
14 * 2.873 1.13 1.54438 55.9
15 * -2.110 1.06
16 INF 0.70 1.51680 64.0
17 INF 0.23
image

The aspherical coefficients of the lens surface of Example 1 are shown in Table 2 below. In the following it (including lens data in Tables), and represents an exponent of 10 (for example, 2.5 × ^{10 -02)} with E (e.g. 2.5E-02).
[Table 2]
Third side
K = -25.077, A3 = 4.1509E-04, A4 = 2.6686E-02, A5 = -3.5274E-06,
A6 = -4.1268E-03, A7 = -1.4243E-06, A8 = 2.3534E-04, A9 = -1.5344E-09,
A10 = -3.0521E-06, A11 = 3.8578E-09, A12 = -8.8504E-08
4th side
K = -0.811, A3 = -3.1773E-03, A4 = 2.9340E-02, A5 = 3.0006E-04,
A6 = 1.0939E-02, A7 = 7.0688E-05, A8 = -1.7602E-03, A9 = 1.3531E-07,
A10 = -7.6839E-04, A11 = -2.3277E-06, A12 = 1.3366E-04
Side 5
K = -37.166, A3 = 0.000E + 00, A4 = 2.4528E-02, A5 = 0.000E + 00,
A6 = 3.6392E-03, A7 = 0.000E + 00, A8 = -7.2690E-04, A9 = 0.000E + 00,
A10 = -1.8210E-05, A11 = 0.000E + 00, A12 = 0.000E + 00
Side 6
K = 23.563, A3 = 0.000E + 00, A4 = 1.0997E-03, A5 = 0.000E + 00,
A6 = 1.4216E-02, A7 = 0.000E + 00, A8 = -5.4242E-03, A9 = 0.000E + 00,
A10 = 7.1859E-04, A11 = 0.000E + 00, A12 = 0.000E + 00
7th page
K = -0.018, A3 = 0.000E + 00, A4 = -1.3978E-02, A5 = 0.000E + 00,
A6 = 3.5903E-03, A7 = 0.000E + 00, A8 = 2.5845E-03, A9 = 0.000E + 00,
A10 = -4.8319E-04, A11 = 0.000E + 00, A12 = 0.000E + 00
8th page
K = -0.223, A3 = 0.000E + 00, A4 = 1.5099E-02, A5 = 0.000E + 00,
A6 = 2.9600E-03, A7 = 0.000E + 00, A8 = 8.3464E-04, A9 = 0.000E + 00,
A10 = 5.9837E-06, A11 = 0.000E + 00, A12 = 0.000E + 00
12th page
K = 3.265, A3 = -5.1410E-03, A4 = -6.7048E-02, A5 = -4.2070E-04,
A6 = 9.0069E-02, A7 = -3.1044E-05, A8 = -1.4354E-02, A9 = 3.2311E-04,
A10 = -2.0751E-02, A11 = -3.8932E-05, A12 = 1.2127E-02
Page 13
K = -25.945, A3 = 3.9543E-03, A4 = -8.8412E-02, A5 = -3.9549E-04,
A6 = 5.0067E-02, A7 = -1.6999E-04, A8 = -6.4724E-03, A9 = -5.7314E-05,
A10 = -5.5126E-03, A11 = 5.4156E-05, A12 = 1.4799E-03
Page 14
K = 0.097, A3 = 0.000E + 00, A4 = -3.8507E-02, A5 = 0.000E + 00,
A6 = 1.3087E-02, A7 = 0.000E + 00, A8 = -1.4666E-03, A9 = 0.000E + 00,
A10 = -5.0820E-04, A11 = 0.000E + 00, A12 = -2.8403E-04
Page 15
K = -0.007, A3 = 0.000E + 00, A4 = 1.1312E-01, A5 = 0.000E + 00,
A6 = -8.0008E-03, A7 = 0.000E + 00, A8 = -4.5930E-03, A9 = 0.000E + 00,
A10 = 1.2483E-03, A11 = 0.000E + 00, A12 = -1.7207E-04

FIG. 2A is a cross-sectional view of the imaging optical system 10A and the like according to the first embodiment. The imaging optical system 10A includes a first lens L1 having a negative refractive power, a second lens L2 having a negative refractive power, and a third lens L3 having a positive refractive power as the first lens group Gr1. It is provided with a fourth lens L4 having a refractive power of. Further, the imaging optical system 10A includes a fifth lens L5 having a positive refractive power, a sixth lens L6 having a negative refractive power, and a seventh lens L7 having a positive refractive power as the second lens group Gr2. To be equipped with. The first and fifth lenses L1 and L5 are made of glass. The second, third, fourth, sixth, and seventh lenses L2, L3, L4, L6, and L7 are made of plastic. An aperture diaphragm ST is arranged between the fourth lens L4 and the fifth lens L5. A filter F having an appropriate thickness is arranged between the seventh lens L7 and the image sensor 51. The filter F is a parallel flat plate assuming an optical low-pass filter, an IR cut filter, a seal glass of the image sensor 51, and the like. Reference numeral I indicates an image pickup surface which is a projection plane of the image pickup device 51. The same applies to the reference numerals F and I in the following examples.

2B and 2C show aberration diagrams (spherical aberration and astigmatism) of the imaging optical system 10A of the first embodiment.

(Example 2)
The overall specifications of the imaging optical system of Example 2 are shown below.
f: 0.79 (mm)
Fno: 2.00
w: 109.0 (°)
ymax: 1.93 (mm)
TL: 17.58 (mm)
BF: 1.69 (mm)
PDΔ + 00: 00.010 (mm)
PDΔ-65: -0.007 (mm)

The data of the lens surface of the imaging optical system of Example 2 is shown in Table 3 below.
[Table 3]
Surf. NR (mm) D (mm) nd vd
1 15.270 0.90 1.80279 44.5
2 4.091 3.29
3 * -3.531 0.70 1.54438 55.9
4 * 2.593 1.84
5 * 5.364 1.41 1.63469 23.9
6 * -6.701 0.37
7 * -3.586 2.50 1.54438 55.9
8 * -2.622 0.46
9 ST INF 0.30
10 11.609 1.53 1.71858 55.3
11 -2.274 0.10
12 * -2.768 0.50 1.63469 23.9
13 * 2.854 0.28
14 * 2.933 1.47 1.54438 55.9
15 * -2.268 1.00
16 INF 0.70 1.51680 64.0
17 INF 0.24
image

The aspherical coefficients of the lens surface of Example 2 are shown in Table 4 below.
[Table 4]
Third side
K = -19.437, A3 = 4.9863E-03, A4 = 2.5428E-02, A5 = 8.9511E-05,
A6 = -4.0374E-03, A7 = 2.7811E-05, A8 = 2.3840E-04, A9 = -2.1963E-06,
A10 = -4.3776E-06, A11 = -3.6092E-07, A12 = 5.9175E-08
4th side
K = -0.382, A3 = -8.8600E-03, A4 = 4.0427E-02, A5 = -7.0662E-03,
A6 = 1.0877E-02, A7 = 8.5756E-04, A8 = -1.4503E-03, A9 = 3.5320E-05,
A10 = -7.7782E-04, A11 = -1.3482E-05, A12 = 1.1987E-04
Side 5
K = -47.864, A3 = 0.000E + 00, A4 = 1.5994E-02, A5 = 0.000E + 00,
A6 = 4.5968E-03, A7 = 0.000E + 00, A8 = -6.4438E-04, A9 = 0.000E + 00,
A10 = -6.4480E-05, A11 = 0.000E + 00, A12 = 0.000E + 00
Side 6
K = 8.693, A3 = 0.000E + 00, A4 = 8.0564E-03, A5 = 0.000E + 00,
A6 = 1.3186E-02, A7 = 0.000E + 00, A8 = -4.6153E-03, A9 = 0.000E + 00,
A10 = 5.4267E-04, A11 = 0.000E + 00, A12 = 0.000E + 00
7th page
K = 0.453, A3 = 0.000E + 00, A4 = 1.1615E-02, A5 = 0.000E + 00,
A6 = -2.2558E-03, A7 = 0.000E + 00, A8 = 4.8023E-04, A9 = 0.000E + 00,
A10 = 6.6170E-05, A11 = 0.000E + 00, A12 = 0.000E + 00
8th page
K = -0.631, A3 = 0.000E + 00, A4 = 1.2246E-02, A5 = 0.000E + 00,
A6 = -7.4430E-04, A7 = 0.000E + 00, A8 = 6.3921E-04, A9 = 0.000E + 00,
A10 = -8.6881E-05, A11 = 0.000E + 00, A12 = 0.000E + 00
12th page
K = -3.041, A3 = -2.0645E-02, A4 = -5.2684E-02, A5 = -2.7546E-02,
A6 = 9.9184E-02, A7 = -1.8769E-02, A8 = -3.8630E-02, A9 = -1.4754E-02,
A10 = -2.0615E-02, A11 = 6.1857E-02, A12 = -2.3738E-02
Page 13
K = -45.765, A3 = 5.6264E-02, A4 = -4.2659E-02, A5 = -4.9907E-03,
A6 = 2.6031E-02, A7 = -1.0363E-02, A8 = -2.6244E-03, A9 = 2.2607E-03,
A10 = -2.6797E-03, A11 = 1.9979E-04, A12 = 7.6732E-04
Page 14
K = -0.903, A3 = 0.000E + 00, A4 = -4.9819E-02, A5 = 0.000E + 00,
A6 = 2.2349E-02, A7 = 0.000E + 00, A8 = -2.8134E-03, A9 = 0.000E + 00,
A10 = -2.8972E-04, A11 = 0.000E + 00, A12 = 1.0945E-04
Page 15
K = 0.108, A3 = 0.000E + 00, A4 = 5.2170E-02, A5 = 0.000E + 00,
A6 = -9.2593E-03, A7 = 0.000E + 00, A8 = -1.6750E-04, A9 = 0.000E + 00,
A10 = 2.0133E-03, A11 = 0.000E + 00, A12 = -3.0057E-04

FIG. 3A is a cross-sectional view of the imaging optical system 10B and the like according to the second embodiment. The imaging optical system 10B includes a first lens L1 having a negative refractive power, a second lens L2 having a negative refractive power, and a third lens L3 having a positive refractive power as the first lens group Gr1. It is provided with a fourth lens L4 having a refractive power of. Further, the imaging optical system 10B includes a fifth lens L5 having a positive refractive power, a sixth lens L6 having a negative refractive power, and a seventh lens L7 having a positive refractive power as the second lens group Gr2. To be equipped with. The first and fifth lenses L1 and L5 are made of glass. The second, third, fourth, sixth, and seventh lenses L2, L3, L4, L6, and L7 are made of plastic. An aperture diaphragm ST is arranged between the fourth lens L4 and the fifth lens L5. A filter F having an appropriate thickness is arranged between the seventh lens L7 and the image sensor 51.

3B and 3C show aberration diagrams (spherical aberration and astigmatism) of the imaging optical system 10B of the second embodiment.

(Example 3)
The overall specifications of the imaging optical system of Example 3 are shown below.
f: 0.80 (mm)
Fno: 2.00
w: 109.0 (°)
ymax: 1.88 (mm)
TL: 18.38 (mm)
BF: 1.76 (mm)
PDΔ + 100: 0.012 (mm)
PDΔ-65: -0.008 (mm)

The data of the lens surface of the imaging optical system of Example 3 is shown in Table 5 below.
[Table 5]
Surf. NR (mm) D (mm) nd vd
1 22.006 2.31 1.79080 46.3
2 4.631 3.07
3 * -4.695 0.70 1.54438 55.9
4 * 2.230 1.85
5 * 6.283 1.28 1.63469 23.9
6 * -8.024 0.38
7 * -4.595 2.72 1.54438 55.9
8 * -2.559 0.20
9 ST INF 0.30
10 11.142 1.59 1.71047 55.7
11 -2.235 0.10
12 * -2.417 0.50 1.63469 23.9
13 * 3.303 0.22
14 * 3.141 1.16 1.54438 55.9
15 * -2.280 1.06
16 INF 0.70 1.51680 64.0
17 INF 0.24
image

The aspherical coefficients of the lens surface of Example 3 are shown in Table 6 below.
[Table 6]
Third side
K = -43.995, A4 = 2.7253E-02, A6 = -4.0502E-03, A8 = 2.2958E-04,
A10 = -4.1245E-06, A12 = -2.8666E-08, A14 = 0.000E + 00
4th side
K = -0.514, A4 = 3.4588E-02, A6 = 1.0951E-02, A8 = -2.0186E-03,
A10 = -8.0314E-04, A12 = 1.3334E-04, A14 = 0.000E + 00
Side 5
K = -50.000, A4 = 1.6824E-02, A6 = 4.4598E-03, A8 = -4.0892E-04,
A10 = -1.0623E-04, A12 = 0.000E + 00, A14 = 0.000E + 00
Side 6
K = 13.039, A4 = -2.3680E-03, A6 = 1.4067E-02, A8 = -4.3421E-03,
A10 = 5.2746E-04, A12 = 0.000E + 00, A14 = 0.000E + 00
7th page
K = -1.290, A4 = -1.4352E-02, A6 = 2.9914E-03, A8 = -5.5569E-05,
A10 = 8.8188E-05, A12 = 0.000E + 00, A14 = 0.000E + 00
8th page
K = -0.447, A4 = 1.5161E-02, A6 = -6.6790E-04, A8 = 1.6586E-03,
A10 = -4.9605E-04, A12 = 0.000E + 00, A14 = 0.000E + 00
12th page
K = 2.102, A4 = -3.2293E-02, A6 = 5.7594E-02, A8 = -1.7848E-02,
A10 = -4.3111E-03, A12 = 5.8077E-03, A14 = 0.000E + 00
Page 13
K = -5.879, A4 = -7.9747E-02, A6 = 4.7202E-02, A8 = -8.1966E-03,
A10 = -5.7734E-03, A12 = 2.1106E-03, A14 = 0.000E + 00
Page 14
K = 0.311, A4 = -3.7298E-02, A6 = 1.5815E-02, A8 = -5.6439E-04,
A10 = -9.0989E-04, A12 = -2.5118E-04, A14 = 2.0159E-05
Page 15
K = 0.307, A4 = 7.1796E-02, A6 = 1.1905E-04, A8 = 2.4355E-04,
A10 = 1.2749E-03, A12 = -8.1303E-04, A14 = 7.4716E-05

FIG. 4A is a cross-sectional view of the imaging optical system 10C and the like according to the third embodiment. The imaging optical system 10C includes a first lens L1 having a negative refractive power, a second lens L2 having a negative refractive power, and a third lens L3 having a positive refractive power as the first lens group Gr1. It is provided with a fourth lens L4 having a refractive power of. Further, the imaging optical system 10C includes a fifth lens L5 having a positive refractive power, a sixth lens L6 having a negative refractive power, and a seventh lens L7 having a positive refractive power as the second lens group Gr2. To be equipped with. The first and fifth lenses L1 and L5 are made of glass. The second, third, fourth, sixth, and seventh lenses L2, L3, L4, L6, and L7 are made of plastic. An aperture diaphragm ST is arranged between the fourth lens L4 and the fifth lens L5. A filter F having an appropriate thickness is arranged between the seventh lens L7 and the image sensor 51.

4B and 4C show aberration diagrams (spherical aberration and astigmatism) of the imaging optical system 10C of the third embodiment.

(Example 4)
The overall specifications of the imaging optical system of Example 4 are shown below.
f: 0.89 (mm)
Fno: 2.00
w: 109.0 (°)
ymax: 1.91 (mm)
TL: 18.59 (mm)
BF: 1.90 (mm)
PDΔ + 100: 0.009 (mm)
PDΔ-65: -0.010 (mm)

The data of the lens surface of the imaging optical system of Example 4 is shown in Table 7 below.
[Table 7]
Surf. NR (mm) D (mm) nd vd
1 17.628 1.85 1.77250 49.6
2 4.267 3.54
3 * -8.977 0.91 1.54438 55.9
4 * 2.154 1.73
5 * 5.464 1.35 1.63469 23.9
6 * -8.851 0.43
7 * -4.020 2.51 1.54438 55.9
8 * -2.625 0.55
9 ST INF 0.19
10 7.840 1.32 1.72916 54.7
11 -2.480 0.10
12 * -2.218 0.50 1.63469 23.9
13 * 3.572 0.23
14 * 3.472 1.25 1.54438 55.9
15 * -2.205 1.12
16 INF 0.70 1.51680 64.0
17 INF 0.32
image

The aspherical coefficients of the lens surface of Example 4 are shown in Table 8 below.
[Table 8]
Third side
K = -49.998, A3 = -1.0581E-03, A4 = 2.7633E-02, A5 = 1.8548E-04,
A6 = -3.9424E-03, A7 = 6.4290E-06, A8 = 2.2756E-04, A9 = -1.0998E-06,
A10 = -5.1477E-06, A11 = -4.0259E-08, A12 = 3.1999E-08, A13 = 0.000E + 00,
A14 = 0.000E + 00
4th side
K = -0.559, A3 = -1.6913E-02, A4 = 3.8109E-02, A5 = 2.3290E-04,
A6 = 1.0715E-02, A7 = -1.7913E-04, A8 = -1.8609E-03, A9 = 3.5529E-05,
A10 = -7.3099E-04, A11 = 7.4857E-06, A12 = 1.1418E-04, A13 = 0.000E + 00,
A14 = 0.000E + 00
Side 5
K = -35.725, A3 = 0.000E + 00, A4 = 1.3648E-02, A5 = 0.000E + 00,
A6 = 4.3986E-03, A7 = 0.000E + 00, A8 = -5.5820E-04, A9 = 0.000E + 00,
A10 = -8.4976E-05, A11 = 0.000E + 00, A12 = -7.5787E-07, A13 = 0.000E + 00,
A14 = 0.000E + 00
Side 6
K = 13.667, A3 = 0.000E + 00, A4 = 1.0876E-04, A5 = 0.000E + 00,
A6 = 1.4886E-02, A7 = 0.000E + 00, A8 = -4.3582E-03, A9 = 0.000E + 00,
A10 = 5.2028E-04, A11 = 0.000E + 00, A12 = -1.7726E-06, A13 = 0.000E + 00,
A14 = 0.000E + 00
7th page
K = -5.778, A3 = 0.000E + 00, A4 = -7.6930E-03, A5 = 0.000E + 00,
A6 = 3.8230E-03, A7 = 0.000E + 00, A8 = -1.1120E-03, A9 = 0.000E + 00,
A10 = 1.4666E-04, A11 = 0.000E + 00, A12 = 2.5484E-05, A13 = 0.000E + 00,
A14 = 0.000E + 00
8th page
K = -0.152, A3 = 0.000E + 00, A4 = 1.1415E-02, A5 = 0.000E + 00,
A6 = -1.4935E-03, A7 = 0.000E + 00, A8 = 8.4573E-04, A9 = 0.000E + 00,
A10 = -1.9663E-04, A11 = 0.000E + 00, A12 = 2.2336E-05, A13 = 0.000E + 00,
A14 = 0.000E + 00
12th page
K = 1.931, A3 = 0.000E + 00, A4 = -1.5545E-02, A5 = 0.000E + 00,
A6 = 4.7387E-02, A7 = 0.000E + 00, A8 = -2.0169E-02, A9 = 0.000E + 00,
A10 = 2.7025E-03, A11 = 0.000E + 00, A12 = 5.8141E-03, A13 = 0.000E + 00,
A14 = 2.9816E-04
Page 13
K = 0.705, A3 = 0.000E + 00, A4 = -6.6780E-02, A5 = 0.000E + 00,
A6 = 3.4333E-02, A7 = 0.000E + 00, A8 = -1.3643E-02, A9 = 0.000E + 00,
A10 = -9.0842E-04, A11 = 0.000E + 00, A12 = 2.0765E-03, A13 = 0.000E + 00,
A14 = -2.9158E-04
Page 14
K = 0.986, A3 = 7.8709E-03, A4 = -3.0507E-02, A5 = -1.2686E-03,
A6 = 1.2926E-02, A7 = -8.1322E-04, A8 = -3.9591E-04, A9 = 1.2353E-04,
A10 = -1.2914E-03, A11 = 1.6489E-04, A12 = 5.1176E-05, A13 = 3.4655E-05,
A14 = 1.9999E-05
Page 15
K = 0.244, A3 = -3.1161E-03, A4 = 5.5250E-02, A5 = -2.0293E-03,
A6 = -7.7412E-03, A7 = 5.6340E-06, A8 = 3.4746E-03, A9 = 1.3149E-04,
A10 = 2.1851E-03, A11 = 2.2870E-05, A12 = -1.3919E-03, A13 = 1.3934E-05,
A14 = 1.9594E-04

FIG. 5A is a cross-sectional view of the imaging optical system 10D and the like according to the fourth embodiment. The imaging optical system 10D includes a first lens L1 having a negative refractive power, a second lens L2 having a negative refractive power, a third lens L3 having a positive refractive power, and a positive lens group Gr1 as the first lens group Gr1. It is provided with a fourth lens L4 having a refractive power of. Further, the imaging optical system 10D includes a fifth lens L5 having a positive refractive power, a sixth lens L6 having a negative refractive power, and a seventh lens L7 having a positive refractive power as the second lens group Gr2. To be equipped with. The first and fifth lenses L1 and L5 are made of glass. The second, third, fourth, sixth, and seventh lenses L2, L3, L4, L6, and L7 are made of plastic. An aperture diaphragm ST is arranged between the fourth lens L4 and the fifth lens L5. A filter F having an appropriate thickness is arranged between the seventh lens L7 and the image sensor 51.

5B and 5C show aberration diagrams (spherical aberration and astigmatism) of the imaging optical system 10D of the fourth embodiment.

(Example 5)
The overall specifications of the imaging optical system of Example 5 are shown below.
f: 0.81 (mm)
Fno: 2.00
w: 109.0 (°)
ymax: 1.88 (mm)
TL: 18.04 (mm)
BF: 1.76 (mm)
PDΔ + 100: 0.011 (mm)
PDΔ-65: -0.008 (mm)

The data of the lens surface of the imaging optical system of Example 5 is shown in Table 9 below.
[Table 9]
Surf. NR (mm) D (mm) nd vd
1 20.422 1.70 1.77250 49.6
2 4.682 2.91
3 * -6.850 0.72 1.54438 55.9
4 * 2.059 2.19
5 * 6.649 1.22 1.63469 23.9
6 * -8.845 0.41
7 * -4.188 2.49 1.54438 55.9
8 * -2.556 0.46
9 ST INF 0.30
10 12.317 1.56 1.72916 54.7
11 -2.225 0.10
12 * -2.349 0.50 1.63469 23.9
13 * 3.873 0.23
14 * 3.598 1.24 1.54438 55.9
15 * -2.245 1.06
16 INF 0.70 1.51680 64.0
17 INF 0.24
image

The aspherical coefficients of the lens surface of Example 5 are shown in Table 10 below.
[Table 10]
Third side
K = -43.326, A3 = -1.3463E-03, A4 = 2.7568E-02, A5 = 1.6996E-04,
A6 = -3.9462E-03, A7 = 5.4976E-06, A8 = 2.2756E-04, A9 = -1.1389E-06,
A10 = -5.1485E-06, A11 = -3.5966E-08, A12 = 3.5308E-08, A13 = 0.000E + 00,
A14 = 0.000E + 00
4th side
K = -0.556, A3 = -1.9453E-02, A4 = 3.8281E-02, A5 = 3.6781E-04,
A6 = 1.0732E-02, A7 = -1.9297E-04, A8 = -1.8747E-03, A9 = 2.7190E-05,
A10 = -7.3481E-04, A11 = 6.2702E-06, A12 = 1.1416E-04, A13 = 0.000E + 00,
A14 = 0.000E + 00
Side 5
K = -50.000, A3 = 0.000E + 00, A4 = 1.5736E-02, A5 = 0.000E + 00,
A6 = 4.5509E-03, A7 = 0.000E + 00, A8 = -6.0222E-04, A9 = 0.000E + 00,
A10 = -9.7002E-05, A11 = 0.000E + 00, A12 = 3.0655E-08, A13 = 0.000E + 00,
A14 = 0.000E + 00
Side 6
K = 14.606, A3 = 0.000E + 00, A4 = -1.4220E-03, A5 = 0.000E + 00,
A6 = 1.4574E-02, A7 = 0.000E + 00, A8 = -4.4709E-03, A9 = 0.000E + 00,
A10 = 4.8044E-04, A11 = 0.000E + 00, A12 = -1.4399E-06, A13 = 0.000E + 00,
A14 = 0.000E + 00
7th page
K = -2.153, A3 = 0.000E + 00, A4 = -1.1274E-02, A5 = 0.000E + 00,
A6 = 4.3360E-03, A7 = 0.000E + 00, A8 = -7.0573E-04, A9 = 0.000E + 00,
A10 = 1.6174E-04, A11 = 0.000E + 00, A12 = -1.9886E-06, A13 = 0.000E + 00,
A14 = 0.000E + 00
8th page
K = -0.504, A3 = 0.000E + 00, A4 = 1.4891E-02, A5 = 0.000E + 00,
A6 = -7.3587E-04, A7 = 0.000E + 00, A8 = 6.0145E-04, A9 = 0.000E + 00,
A10 = -1.3697E-04, A11 = 0.000E + 00, A12 = 1.3287E-07, A13 = 0.000E + 00,
A14 = 0.000E + 00
12th page
K = 2.019, A3 = 0.000E + 00, A4 = -1.2223E-02, A5 = 0.000E + 00,
A6 = 4.3372E-02, A7 = 0.000E + 00, A8 = -2.0768E-02, A9 = 0.000E + 00,
A10 = 2.0672E-03, A11 = 0.000E + 00, A12 = 4.9736E-03, A13 = 0.000E + 00,
A14 = -1.6863E-04
Page 13
K = 1.091, A3 = 0.000E + 00, A4 = -6.6179E-02, A5 = 0.000E + 00,
A6 = 3.7370E-02, A7 = 0.000E + 00, A8 = -1.2891E-02, A9 = 0.000E + 00,
A10 = -1.8344E-03, A11 = 0.000E + 00, A12 = 1.5207E-03, A13 = 0.000E + 00,
A14 = -1.5548E-05
Page 14
K = 0.756, A3 = -6.5893E-04, A4 = -3.2252E-02, A5 = -1.4431E-04,
A6 = 1.4249E-02, A7 = -5.9184E-05, A8 = -1.6694E-04, A9 = 6.1069E-05,
A10 = -1.4542E-03, A11 = 9.2060E-06, A12 = -5.2478E-05, A13 = -8.5175E-06,
A14 = 2.9261E-05
Page 15
K = 0.226, A3 = 5.2029E-04, A4 = 5.9132E-02, A5 = -1.4943E-04,
A6 = -7.0942E-03, A7 = 8.1693E-05, A8 = 3.3660E-03, A9 = 1.7558E-05,
A10 = 2.1182E-03, A11 = -5.1723E-06, A12 = -1.4048E-03, A13 = -1.4693E-06,
A14 = 1.7112E-04

FIG. 6A is a cross-sectional view of the imaging optical system 10E and the like according to the fifth embodiment. The imaging optical system 10E includes a first lens L1 having a negative refractive power, a second lens L2 having a negative refractive power, and a third lens L3 having a positive refractive power as the first lens group Gr1. It is provided with a fourth lens L4 having a refractive power of. Further, the imaging optical system 10E includes a fifth lens L5 having a positive refractive power, a sixth lens L6 having a negative refractive power, and a seventh lens L7 having a positive refractive power as the second lens group Gr2. To be equipped with. The first and fifth lenses L1 and L5 are made of glass. The second, third, fourth, sixth, and seventh lenses L2, L3, L4, L6, and L7 are made of plastic. An aperture diaphragm ST is arranged between the fourth lens L4 and the fifth lens L5. A filter F having an appropriate thickness is arranged between the seventh lens L7 and the image sensor 51.

6B and 6C show aberration diagrams (spherical aberration and astigmatism) of the imaging optical system 10E of Example 5.

(Example 6)
The overall specifications of the imaging optical system of Example 6 are shown below.
f: 0.73 (mm)
Fno: 2.00
w: 109.0 (°)
ymax: 2.03 (mm)
TL: 19.56 (mm)
BF: 1.64 (mm)
PDΔ + 00: 0.006 (mm)
PDΔ-65: -0.004 (mm)

The data of the lens surface of the imaging optical system of Example 6 is shown in Table 11 below.
[Table 11]
Surf. NR (mm) D (mm) nd vd
1 15.491 2.25 1.77250 49.6
2 4.024 3.95
3 * -5.041 0.82 1.54438 55.9
4 * 1.948 1.94
5 * 4.788 1.79 1.63469 23.9
6 * -9.289 0.37
7 * -4.139 2.51 1.54438 55.9
8 * -2.566 0.63
9 ST INF 0.15
10 8.111 1.13 1.72916 54.7
11 -2.285 0.10
12 * -2.284 0.50 1.63469 23.9
13 * 3.895 0.18
14 * 3.754 1.35 1.54438 55.9
15 * -2.398 1.00
16 INF 0.70 1.51680 64.0
17 INF 0.18
image

The aspherical coefficients of the lens surface of Example 6 are shown in Table 12 below.
[Table 12]
Third side
K = -50.000, A3 = -9.1548E-04, A4 = 2.7579E-02, A5 = 1.6370E-04,
A6 = -3.9497E-03, A7 = 4.2265E-06, A8 = 2.2727E-04, A9 = -1.2283E-06,
A10 = -5.1621E-06, A11 = -3.5802E-08, A12 = 3.6978E-08, A13 = 0.000E + 00,
A14 = 0.000E + 00
4th side
K = -0.564, A3 = -1.7505E-02, A4 = 3.8270E-02, A5 = 4.4551E-06,
A6 = 1.0609E-02, A7 = -2.0844E-04, A8 = -1.8642E-03, A9 = 3.8521E-05,
A10 = -7.2849E-04, A11 = 8.5372E-06, A12 = 1.1428E-04, A13 = 0.000E + 00,
A14 = 0.000E + 00
Side 5
K = -30.526, A3 = 0.000E + 00, A4 = 1.2311E-02, A5 = 0.000E + 00,
A6 = 4.5118E-03, A7 = 0.000E + 00, A8 = -4.9406E-04, A9 = 0.000E + 00,
A10 = -6.9409E-05, A11 = 0.000E + 00, A12 = 2.9296E-06, A13 = 0.000E + 00,
A14 = 0.000E + 00
Side 6
K = -3.752, A3 = 0.000E + 00, A4 = 3.5615E-03, A5 = 0.000E + 00,
A6 = 1.5732E-02, A7 = 0.000E + 00, A8 = -4.3476E-03, A9 = 0.000E + 00,
A10 = 5.3509E-04, A11 = 0.000E + 00, A12 = 9.3207E-06, A13 = 0.000E + 00,
A14 = 0.000E + 00
7th page
K = -10.730, A3 = 0.000E + 00, A4 = -3.091E-03, A5 = 0.000E + 00,
A6 = 4.7784E-03, A7 = 0.000E + 00, A8 = -1.0003E-03, A9 = 0.000E + 00,
A10 = 1.6854E-04, A11 = 0.000E + 00, A12 = 5.1899E-05, A13 = 0.000E + 00,
A14 = 0.000E + 00
8th page
K = -0.505, A3 = 0.000E + 00, A4 = 1.5424E-02, A5 = 0.000E + 00,
A6 = -4.0302E-03, A7 = 0.000E + 00, A8 = 2.7348E-03, A9 = 0.000E + 00,
A10 = -9.6336E-04, A11 = 0.000E + 00, A12 = 1.6312E-04, A13 = 0.000E + 00,
A14 = 0.000E + 00
12th page
K = 2.458, A3 = 0.000E + 00, A4 = -1.7669E-02, A5 = 0.000E + 00,
A6 = 5.8714E-02, A7 = 0.000E + 00, A8 = -5.6091E-02, A9 = 0.000E + 00,
A10 = 7.3150E-03, A11 = 0.000E + 00, A12 = 5.3075E-02, A13 = 0.000E + 00,
A14 = -2.5266E-02
Page 13
K = 2.224, A3 = 0.000E + 00, A4 = -6.0265E-02, A5 = 0.000E + 00,
A6 = 2.4575E-02, A7 = 0.000E + 00, A8 = -1.8429E-02, A9 = 0.000E + 00,
A10 = 1.0305E-03, A11 = 0.000E + 00, A12 = 4.4917E-03, A13 = 0.000E + 00,
A14 = -1.0437E-03
Page 14
K = 2.728, A3 = 1.6170E-02, A4 = -2.3219E-02, A5 = 2.6594E-03,
A6 = 1.4892E-02, A7 = 1.7039E-05, A8 = -3.2703E-04, A9 = -2.5749E-04,
A10 = -1.8105E-03, A11 = -2.5470E-04, A12 = -1.4293E-04, A13 = 9.6073E-05,
A14 = 3.0211E-04
Page 15
K = 0.140, A3 = 1.3489E-02, A4 = 5.9266E-02, A5 = -9.3661E-04,
A6 = -6.6899E-03, A7 = 1.3560E-03, A8 = 4.8167E-03, A9 = 1.1933E-03,
A10 = 2.8629E-03, A11 = 3.4374E-04, A12 = -1.3350E-03, A13 = -8.7402E-05,
A14 = 2.3891E-05

FIG. 7A is a cross-sectional view of the imaging optical system 10F and the like according to the sixth embodiment. The imaging optical system 10F includes a first lens L1 having a negative refractive power, a second lens L2 having a negative refractive power, a third lens L3 having a positive refractive power, and a positive lens group Gr1 as the first lens group Gr1. It is provided with a fourth lens L4 having a refractive power of. Further, the imaging optical system 10F includes a fifth lens L5 having a positive refractive power, a sixth lens L6 having a negative refractive power, and a seventh lens L7 having a positive refractive power as the second lens group Gr2. To be equipped with. The first and fifth lenses L1 and L5 are made of glass. The second, third, fourth, sixth, and seventh lenses L2, L3, L4, L6, and L7 are made of plastic. An aperture diaphragm ST is arranged between the fourth lens L4 and the fifth lens L5. A filter F having an appropriate thickness is arranged between the seventh lens L7 and the image sensor 51.

7B and 7C show aberration diagrams (spherical aberration and astigmatism) of the imaging optical system 10F of the sixth embodiment.

(Example 7)
The overall specifications of the imaging optical system of Example 7 are shown below.
f: 0.84 (mm)
Fno: 1.99
w: 100.0 (°)
ymax: 1.84 (mm)
TL: 19.57 (mm)
BF: 1.59 (mm)
PDΔ + 00: 0.000 (mm)
PDΔ-65: -0.001 (mm)

The data of the lens surface of the imaging optical system of Example 7 is shown in Table 13 below.
[Table 13]
Surf. NR (mm) D (mm) nd vd
1 20.000 2.50 1.72916 54.7
2 5.203 4.08
3 * -8.321 0.71 1.54438 55.9
4 * 1.509 2.00
5 * 6.106 1.76 1.63469 23.9
6 * -10.400 0.26
7 * -5.980 1.92 1.54438 55.9
8 * -2.757 0.98
9 ST INF 0.20
10 5.017 1.42 1.72916 54.7
11 -2.134 0.10
12 * -1.974 0.45 1.63469 23.9
13 * 2.801 0.26
14 * 2.971 1.10 1.54438 55.9
15 * -2.584 0.96
16 INF 0.70 1.51680 64.0
17 INF 0.17
image

The aspherical coefficients of the lens surface of Example 7 are shown in Table 14 below.
[Table 14]
Third side
K = -50.000, A3 = 1.8697E-02, A4 = 1.9301E-02, A5 = 1.2271E-04,
A6 = -3.7715E-03, A7 = 3.9243E-05, A8 = 2.2534E-04, A9 = -2.2663E-06,
A10 = -4.8304E-06, A11 = -7.2830E-08, A12 = 2.6580E-08, A13 = 0.000E + 00,
A14 = 0.000E + 00
4th side
K = -0.659, A3 = -3.3934E-02, A4 = 3.9438E-02, A5 = 2.4686E-03,
A6 = 9.3074E-03, A7 = -9.8364E-04, A8 = -2.1815E-03, A9 = 5.5271E-05,
A10 = -6.7812E-04, A11 = 3.1759E-05, A12 = 1.0921E-04, A13 = 0.000E + 00,
A14 = 0.000E + 00
Side 5
K = -59.852, A3 = 0.000E + 00, A4 = 3.5244E-03, A5 = 0.000E + 00,
A6 = 4.6005E-03, A7 = 0.000E + 00, A8 = -3.7101E-04, A9 = 0.000E + 00,
A10 = -8.6812E-05, A11 = 0.000E + 00, A12 = 0.000E + 00, A13 = 0.000E + 00,
A14 = 0.000E + 00
Side 6
K = 25.756, A3 = 0.000E + 00, A4 = 8.9415E-03, A5 = 0.000E + 00,
A6 = 1.6607E-02, A7 = 0.000E + 00, A8 = -4.3929E-03, A9 = 0.000E + 00,
A10 = 5.2797E-04, A11 = 0.000E + 00, A12 = 0.000E + 00, A13 = 0.000E + 00,
A14 = 0.000E + 00
7th page
K = -10.285, A3 = 0.000E + 00, A4 = 6.0512E-03, A5 = 0.000E + 00,
A6 = 2.3644E-03, A7 = 0.000E + 00, A8 = -1.9557E-03, A9 = 0.000E + 00,
A10 = 3.9852E-04, A11 = 0.000E + 00, A12 = 0.000E + 00, A13 = 0.000E + 00,
A14 = 0.000E + 00
8th page
K = 0.047, A3 = 0.000E + 00, A4 = 1.7068E-03, A5 = 0.000E + 00,
A6 = -7.3218E-04, A7 = 0.000E + 00, A8 = 3.7586E-04, A9 = 0.000E + 00,
A10 = -5.2854E-05, A11 = 0.000E + 00, A12 = 0.000E + 00, A13 = 0.000E + 00,
A14 = 0.000E + 00
12th page
K = 1.658, A3 = 0.000E + 00, A4 = -2.8576E-02, A5 = 0.000E + 00,
A6 = 5.7440E-02, A7 = 0.000E + 00, A8 = -2.1242E-02, A9 = 0.000E + 00,
A10 = -3.6782E-03, A11 = 0.000E + 00, A12 = 1.6001E-02, A13 = 0.000E + 00,
A14 = 0.000E + 00
Page 13
K = 1.123, A3 = 0.000E + 00, A4 = -8.4925E-02, A5 = 0.000E + 00,
A6 = 5.0238E-02, A7 = 0.000E + 00, A8 = -2.5685E-02, A9 = 0.000E + 00,
A10 = 2.6685E-03, A11 = 0.000E + 00, A12 = 1.0534E-03, A13 = 0.000E + 00,
A14 = 0.000E + 00
Page 14
K = 0.444, A3 = 0.000E + 00, A4 = -3.6392E-02, A5 = 0.000E + 00,
A6 = -1.9949E-03, A7 = 0.000E + 00, A8 = 5.1362E-03, A9 = 0.000E + 00,
A10 = -1.0195E-03, A11 = 0.000E + 00, A12 = -5.7271E-04, A13 = 0.000E + 00,
A14 = 5.3799E-05
Page 15
K = 0.632, A3 = 0.000E + 00, A4 = 3.3360E-02, A5 = 0.000E + 00,
A6 = -1.5096E-02, A7 = 0.000E + 00, A8 = -3.3330E-05, A9 = 0.000E + 00,
A10 = 3.3871E-03, A11 = 0.000E + 00, A12 = -6.5761E-04, A13 = 0.000E + 00,
A14 = -7.7693E-05

FIG. 8A is a cross-sectional view of the imaging optical system 10G and the like according to the seventh embodiment. The imaging optical system 10G includes a first lens L1 having a negative refractive power, a second lens L2 having a negative refractive power, and a third lens L3 having a positive refractive power as the first lens group Gr1. It is provided with a fourth lens L4 having a refractive power of. Further, the imaging optical system 10G includes a fifth lens L5 having a positive refractive power, a sixth lens L6 having a negative refractive power, and a seventh lens L7 having a positive refractive power as the second lens group Gr2. To be equipped with. The first and fifth lenses L1 and L5 are made of glass. The second, third, fourth, sixth, and seventh lenses L2, L3, L4, L6, and L7 are made of plastic. An aperture diaphragm ST is arranged between the fourth lens L4 and the fifth lens L5. A filter F having an appropriate thickness is arranged between the seventh lens L7 and the image sensor 51.

8B and 8C show aberration diagrams (spherical aberration and astigmatism) of the imaging optical system 10G of Example 7.

(Example 8)
The overall specifications of the imaging optical system of Example 8 are shown below.
f: 0.72 (mm)
Fno: 1.99
w: 100.0 (°)
ymax: 1.84 (mm)
TL: 17.68 (mm)
BF: 1.28 (mm)
PDΔ + 100: 0.013 (mm)
PDΔ-65: -0.009 (mm)

The data of the lens surface of the imaging optical system of Example 8 is shown in Table 15 below.
[Table 15]
Surf. NR (mm) D (mm) nd vd
1 19.000 2.50 1.72916 54.7
2 3.293 2.84
3 * -8.644 0.70 1.54438 55.9
4 * 6.516 1.64
5 * 3.708 2.51 1.63469 23.9
6 * 6.456 0.34
7 * -10.061 1.39 1.54438 55.9
8 * -3.033 0.87
9 ST INF 0.50
10 13.490 0.86 1.72916 54.7
11 -2.000 0.10
12 * -12.875 0.40 1.63469 23.9
13 * 3.032 0.26
14 * -2.437 1.26 1.54438 55.9
15 * -0.791 0.60
16 INF 0.70 1.51680 64.0
17 INF 0.22
image

The aspherical coefficients of the lens surface of Example 8 are shown in Table 16 below.
[Table 16]
Third side
K = 4.215, A3 = -5.4339E-04, A4 = 3.2110E-02, A5 = 4.2523E-03,
A6 = -5.2070E-03, A7 = -1.6994E-04, A8 = 5.2299E-04, A9 = -5.9794E-06,
A10 = -4.4408E-05, A11 = 7.4808E-06, A12 = -2.8997E-07, A13 = 0.000E + 00,
A14 = 0.000E + 00
4th side
K = -13.696, A3 = -2.8757E-02, A4 = 7.0697E-02, A5 = -2.1760E-02,
A6 = 7.9989E-03, A7 = 6.6484E-04, A8 = -6.5989E-04, A9 = 9.5381E-04,
A10 = -6.2938E-04, A11 = -1.3947E-05, A12 = 3.8557E-05, A13 = 0.000E + 00,
A14 = 0.000E + 00
Side 5
K = 0.542, A3 = 0.000E + 00, A4 = 7.2782E-04, A5 = 0.000E + 00,
A6 = 2.7095E-03, A7 = 0.000E + 00, A8 = -1.1735E-03, A9 = 0.000E + 00,
A10 = 8.8907E-05, A11 = 0.000E + 00, A12 = 0.000E + 00, A13 = 0.000E + 00,
A14 = 0.000E + 00
Side 6
K = -5.780, A3 = 0.000E + 00, A4 = 4.4477E-03, A5 = 0.000E + 00,
A6 = 7.3008E-03, A7 = 0.000E + 00, A8 = -3.4235E-03, A9 = 0.000E + 00,
A10 = 3.7816E-04, A11 = 0.000E + 00, A12 = 0.000E + 00, A13 = 0.000E + 00,
A14 = 0.000E + 00
7th page
K = -23.012, A3 = 0.000E + 00, A4 = 3.0402E-02, A5 = 0.000E + 00,
A6 = 7.3484E-03, A7 = 0.000E + 00, A8 = -3.1278E-03, A9 = 0.000E + 00,
A10 = 3.4053E-04, A11 = 0.000E + 00, A12 = 0.000E + 00, A13 = 0.000E + 00,
A14 = 0.000E + 00
8th page
K = -0.884, A3 = 0.000E + 00, A4 = 4.4666E-02, A5 = 0.000E + 00,
A6 = -1.4394E-02, A7 = 0.000E + 00, A8 = 4.7762E-03, A9 = 0.000E + 00,
A10 = -5.4736E-04, A11 = 0.000E + 00, A12 = 0.000E + 00, A13 = 0.000E + 00,
A14 = 0.000E + 00
12th page
K = -42.497, A3 = 0.000E + 00, A4 = -2.9253E-01, A5 = 0.000E + 00,
A6 = 1.3887E-01, A7 = 0.000E + 00, A8 = -1.1445E-01, A9 = 0.000E + 00,
A10 = 9.8885E-02, A11 = 0.000E + 00, A12 = -3.3092E-02, A13 = 0.000E + 00,
A14 = 0.000E + 00
Page 13
K = -17.046, A3 = 0.000E + 00, A4 = -1.0270E-01, A5 = 0.000E + 00,
A6 = 4.4604E-02, A7 = 0.000E + 00, A8 = -6.9698E-03, A9 = 0.000E + 00,
A10 = -2.5803E-03, A11 = 0.000E + 00, A12 = 3.6186E-04, A13 = 0.000E + 00,
A14 = 0.000E + 00
Page 14
K = -10.267, A3 = 0.000E + 00, A4 = 8.5878E-02, A5 = 0.000E + 00,
A6 = -4.4656E-03, A7 = 0.000E + 00, A8 = -4.1451E-03, A9 = 0.000E + 00,
A10 = 1.1863E-03, A11 = 0.000E + 00, A12 = 2.6443E-06, A13 = 0.000E + 00,
A14 = -4.2861E-06
Page 15
K = -0.810, A3 = 0.000E + 00, A4 = 2.4853E-01, A5 = 0.000E + 00,
A6 = -9.2429E-02, A7 = 0.000E + 00, A8 = 3.7925E-02, A9 = 0.000E + 00,
A10 = 3.3610E-03, A11 = 0.000E + 00, A12 = -3.7038E-03, A13 = 0.000E + 00,
A14 = 6.8361E-04

FIG. 9A is a cross-sectional view of the imaging optical system 10H and the like according to the eighth embodiment. The imaging optical system 10H includes a first lens L1 having a negative refractive power, a second lens L2 having a negative refractive power, a third lens L3 having a positive refractive power, and a positive lens group Gr1 as the first lens group Gr1. It is provided with a fourth lens L4 having a refractive power of. Further, the imaging optical system 10H includes a fifth lens L5 having a positive refractive power, a sixth lens L6 having a negative refractive power, and a seventh lens L7 having a positive refractive power as the second lens group Gr2. To be equipped with. The first and fifth lenses L1 and L5 are made of glass. The second, third, fourth, sixth, and seventh lenses L2, L3, L4, L6, and L7 are made of plastic. An aperture diaphragm ST is arranged between the fourth lens L4 and the fifth lens L5. A filter F having an appropriate thickness is arranged between the seventh lens L7 and the image sensor 51.

9B and 9C show aberration diagrams (spherical aberration and astigmatism) of the imaging optical system 10H of Example 8.

Table 17 below summarizes the values of Examples 1 to 8 corresponding to the conditional expressions (1) to (10) for reference.
[Table 17]

In the above, in the actual lens measurement scene, the radius of curvature of the lens surface referred to in the present application is a shape measurement value in the vicinity of the center of the lens (specifically, the central region within 10% of the outer diameter of the lens). Refers to the approximate radius of curvature when the lens is fitted by the minimum self-squared method. Further, for example, when a quadratic aspherical coefficient is used, the radius of curvature in consideration of the quadratic aspherical coefficient is included in the reference curvature radius of the aspherical surface definition formula.

Although the image pickup optical system and the like have been described above according to the embodiment, the image pickup optical system according to the present invention is not limited to the above embodiment or the embodiment and can be variously modified.

Further, in the above embodiment, the filter F may be configured to be switched at the time of imaging with visible light or near-infrared light in applications such as in-vehicle cameras and surveillance cameras.

Further, in the above embodiment, the lenses L1 to L7 are fixed to the lens barrel 41, but they can be appropriately moved for focusing or the like.

Claims (15)

From the object side, the first lens having a negative refractive power, the second lens having a negative refractive power, the third lens having a positive refractive power, and the fourth lens having a positive refractive power are substantially. With the first lens group that becomes the target
Aperture aperture and
A fifth lens having a positive refractive power, a sixth lens having a negative refractive power, and a second lens group substantially consisting of a seventh lens having a positive refractive power.
Consists of
The fourth lens have a meniscus shape with a concave surface on the object side, the following conditional expression is satisfied, the imaging optical system.
8 ≦ f4 / f ≦ 15… (1)
However,
f4: Focal length of the fourth lens
f: Focal length of the entire lens system The imaging optical system according to claim 1, which satisfies the following conditional expression.
1.9 ≤ d23 / f ≤ 3 ... (2)
However,
d23: Air distance between the second lens and the third lens on the optical axis f: Focal length of the entire lens system The imaging optical system according to any one of claims 1 and 2 , which satisfies the following conditional expression.
0.3 ≤ d34 / f ≤ 0.8 ... (3)
However,
d34: Air distance between the third lens and the fourth lens on the optical axis f: Focal length of the entire lens system The imaging optical system according to any one of claims 1 to 3 , which satisfies the following conditional expression.
0.2 ≦ d67 / f ≦ 0.4… (4)
However,
d67: Air distance between the 6th lens and the 7th lens on the optical axis f: Focal length of the entire lens system The imaging optical system according to any one of claims 1 to 4 , which satisfies the following conditional expression.
0.5 ≤ f1 / f2 ≤ 5 ... (5)
However,
f1: Focal length of the first lens f2: Focal length of the second lens The imaging optical system according to any one of claims 1 to 5 , which satisfies the following conditional expression.
-12 ≤ (r4i + r4o) / (r4i-r4o) <-1 ... (6)
However,
r4i: Radius of curvature of the image side surface of the fourth lens r4o: Radius of curvature of the object side surface of the fourth lens The imaging optical system according to any one of claims 1 to 5 , which satisfies the following conditional expression.
-12 ≤ (r4i + r4o) / (r4i-r4o) ≤ -1.5 ... (7)
However,
r4i: Radius of curvature of the image side surface of the fourth lens r4o: Radius of curvature of the object side surface of the fourth lens The imaging optical system according to any one of claims 1 to 7 , which satisfies the following conditional expression.
2 ≦ f7 / f ≦ 4 ... (8)
However,
f7: Focal length of the 7th lens f: Focal length of the entire lens system The imaging optical system according to any one of claims 1 to 8 , wherein the sixth lens has a biconcave shape. The imaging optical system according to any one of claims 1 to 9 , which satisfies the following conditional expression.
-6 ≤ f6 / f ≤ -2 ... (9)
However,
f6: Focal length of the sixth lens f: Focal length of the entire lens system Of the four lenses in the first lens group, three lenses are made of plastic.
The second lens group has one lens having a positive refractive power made of plastic and one lens having a negative refractive power made of plastic.
The imaging optical system according to any one of claims 1 to 10 , which satisfies the following conditional expression.
−0.32 ≦ f × Σ (1 / fplk) ≦ 0.32… (10)
However,
f: Focal length of the entire lens system fplk: Focal length of the kth plastic lens from the object side The aspect of any one of claims 1 to 11 , wherein the side surface of the object of the second lens has a concave shape on the object side in the vicinity of the optical axis and is located on the image side of the surface apex at the effective diameter position. Imaging optical system. The imaging optical system according to any one of claims 1 to 12.
A lens barrel that holds the imaging optical system and
Lens unit equipped with. The imaging optical system according to any one of claims 1 to 12.
An image sensor that detects an image obtained from the image pickup optical system,
An imaging device comprising. The imaging device according to claim 14 , further comprising a lens barrel that holds the imaging optical system.

Images