JP2022054357A - Lens system, image capturing device, and mobile body - Google Patents

Abstract

To provide an image capturing lens with a relatively wide angle.SOLUTION: A lens system provided herein comprises a first lens group G1, an aperture stop S, and a second lens group G2 in order from the object side. The first lens group G1 comprises a first lens L1 with negative refractive power disposed on the most object side, and at least one lens with positive refractive power disposed on the image side of the first lens L1. The second lens group G2 comprises a lens having positive refractive power, a lens having negative refractive power, and a lens having positive refractive power in order from the object side, and has a bi-aspherical lens on the most image side. The lens system satisfies the following conditional expressions: 1.00<|f1|/f<4.00, -0.2<f/fL<0.2, where f1 represents a focal length of the lens L1 on the most object side, f represents a focal length of the entire system, and fL represents a focal length of the lens L7 on the most image side.SELECTED DRAWING: Figure 1

Description

The present invention relates to a lens system, an image pickup device, and a moving body.

In Patent Document 1 and Patent Document 2, as an image pickup lens having a relatively wide angle, the first lens having a negative refractive power is in order from the object side, the image plane side is closer to the image plane side than the first lens, and the aperture aperture is higher than the aperture aperture. A configuration in which a lens having a positive refractive power, an aperture aperture, a lens having a positive refractive power on the image plane side of the aperture aperture, a lens having a negative refractive power, and a lens having a positive refractive power are arranged on the object side. Have been described.
[Prior Art Document]
[Patent Document]
[Patent Document 1] Japanese Patent No. 6335332 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-194653

The lens system according to one aspect of the present invention includes a first lens group, an aperture diaphragm, and a second lens group in order from the object side. The first lens group includes a first lens having the most negative refractive power on the object side, and at least one lens having a positive refractive power on the image plane side of the first lens. The second lens group includes a lens having a positive refractive power, a lens having a negative refractive power, and a lens having a positive refractive power in order from the object side, and a lens having aspherical surfaces on both sides on the most image plane side. Be prepared. Assuming that the focal length of the lens on the most object side is f1, the focal length of the entire system is f, and the focal length of the lens on the image plane side is fL, the conditional expression 1.00 << | f1 | / f <4.00
-0.2 <f / fL <0.2
To be satisfied.

The lens on the image plane side has a convex shape at the center of both the surface on the object side and the surface on the image plane side, and has an inflection point once up to the peripheral part, and the peripheral part is on the object side. It may have a concave shape.

Conditional expression 1.5 / f_1G / f <10, where the focal length of the first lens group is f_1G.
May be satisfied.

Conditional expression 1.5 / f_2G / f <5.0, where the focal length of the second lens group is f_2G.
May be satisfied.

The lens having the positive refractive power, the lens having the negative refractive power, and the lens having the positive refractive power, which the second lens group has in order from the object side, has the positive refractive power on the object side. The focal distance of is f_p1, and the focal distance of the lens having a positive refractive power on the image plane side is f_p2, and the conditional equation 1.3 <f_p1 / f <2.6
1.1 <f_p2 / f <5.0
May be satisfied.

Conditional expression 2.7 <TTL / Y < 3.6
May be satisfied.

Conditional expression 1.2 <L_sto / Y <2.0, where the distance on the optical axis from the aperture stop to the image plane is L_sho and the maximum image height is Y.
May be satisfied.

The conditional expression 23.0 <v1 <42.0, where v1 is the Abbe number of the lens having a positive refractive power of the first lens group.
May be satisfied.

The conditional equation -1.6 <fn / f <-0.8, where fn is the combined focal length of the lens on the object side of the lens having the positive refractive power of the first lens group.
May be satisfied.

The first lens group may include three or more consecutively adjacent glass lens groups in order from the object side. The second lens group may include four or more consecutive adjacent plastic lenses.

The image pickup apparatus according to one aspect of the present invention includes the above lens system. The image pickup device includes an image sensor.

The moving body according to one aspect of the present invention is provided with the above lens system and moves.

The mobile object may be an unmanned aerial vehicle.

According to the above lens system, it is possible to provide a high-performance lens system having a short optical total length including back focus and a small lens diameter.

The outline of the above invention does not list all the necessary features of the present invention. A subcombination of these feature groups can also be an invention.

The lens configuration of the lens system 100 in the first embodiment is shown together with the optical member P and the image plane IM. It shows spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the lens system 100 in a state of being in focus on an infinity subject. The lens configuration of the lens system 200 in the second embodiment is shown together with the optical member P and the image plane IM. It shows spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the lens system 200 in a state of being in focus on an infinity subject. The lens configuration of the lens system 300 in the third embodiment is shown together with the optical member P and the image plane IM. The spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the lens system 300 in a state of being in focus on an infinity subject are shown. The lens configuration of the lens system 400 in the first reference example is shown together with the optical member P and the image plane IM. The spherical aberration, astigmatism, and distortion in the state of being in focus on the infinity subject of the lens system 400 are shown. The lens configuration of the lens system 500 in the second reference example is shown together with the optical member P and the image plane IM. The spherical aberration, astigmatism, and distortion in the state of being in focus on the infinity subject of the lens system 500 are shown. The lens configuration of the lens system 600 in the third reference example is shown together with the optical member P and the image plane IM. The spherical aberration, astigmatism, and distortion in the state of being in focus on the infinity subject of the lens system 600 are shown. The lens configuration of the lens system 700 in the fourth reference example is shown together with the optical member P and the image plane IM. It shows spherical aberration, astigmatism, and distortion in a state where the lens system 700 is focused on an infinity subject. The lens configuration of the lens system 800 in the fifth reference example is shown together with the optical member P and the image plane IM. The spherical aberration, astigmatism, and distortion in the state of being in focus on the infinity subject of the lens system 800 are shown. The lens configuration of the lens system 900 in the sixth reference example is shown together with the optical member P and the image plane IM. The spherical aberration, astigmatism, and distortion in the state of being in focus on the infinity subject of the lens system 900 are shown. An example of an external perspective view of an image pickup apparatus 2000 including a lens system according to the above embodiment is shown. It is a figure which shows the functional block of the image pickup apparatus 2000. An example of a mobile system 10 including an unmanned aerial vehicle (UAV) 40 and a controller 50 is schematically shown. It is an external perspective view which shows an example of a stabilizer 3000.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential to the means of solving the invention. It will be apparent to those skilled in the art that various changes or improvements can be made to the following embodiments. It is clear from the description of the claims that the form with such changes or improvements may be included in the technical scope of the present invention.

The claims, description, drawings, and abstracts include matters subject to copyright protection. The copyright holder will not object to any person's reproduction of these documents as long as they appear in the Patent Office files or records. However, in other cases, all copyrights are reserved.

When the terms "consisting of", "consisting of", and "consisting of" are used in the present specification and the like, in addition to the listed components, a lens having substantially no refractive power, It may include optical elements other than lenses that have substantially refractive power, such as apertures, filters and cover glass, and / or mechanical elements such as lens flanges, image sensors and runout correction mechanisms. For example, when the terms "consisting of X", "consisting of X", and "consisting of X" are used, in addition to X, an optical element other than a lens having substantially refractive power, and / or a mechanism. Can contain elements.

In the present specification, examples and reference examples in which specific numerical values are applied to specific embodiments of a lens system will be described. First, the meanings of symbols and the like used in the description of each embodiment and reference example of the lens system will be described.

As lens data, a table including the surface number, the radius of curvature, the surface spacing, the refractive index and the Abbe number is disclosed. In the lens data table, the surface number column shows the surface number when the surface on the most object side is the first surface and the number is increased one by one toward the image side. In the column of R, the radius of curvature of each surface is shown. In the column D, the surface distance on the optical axis between each surface and the surface adjacent to the image side is shown. In the column of Nd, the refractive index of each optical element with respect to the d line (wavelength 587.6 nm (nanometer)) is shown. In the column of νd, the Abbe number with respect to the d-line of each optical element is shown. Here, the sign of the radius of curvature is positive when the surface shape is convex toward the object side and negative when the surface shape is convex toward the image plane side. "INF" in the radius of curvature indicates that the surface is a plane.

The lens data includes the aperture stop S. “STO” in the surface number column represents the opening surface of the aperture stop S.

In the lens data, the surface number of the aspherical surface is marked with *, and the value of the radius of curvature of the paraxial axis is shown in the column of radius of curvature. Further, for the embodiment of the lens system having an aspherical surface, a table of aspherical surface data including the surface number of the aspherical surface, the aspherical surface coefficient for each aspherical surface, and the conical constant is attached. In the table of aspherical data, the numerical value "E ± n" (n: natural number) of the aspherical coefficient represents an exponential notation with a base of 10. That is, "E ± n" represents "× 10 ^{± n} ". For example, "0.12345E-05" represents "0.12345 × ^10-5 ". For the aspherical shape, "zd" is the distance (sag amount) in the optical axis direction from the apex of the lens surface, "h" is the distance (height) in the direction perpendicular to the optical axis direction, and "c" is the apex of the lens. Assuming that the near-axis curvature (inverse number of the radius of curvature), "κ" is a conical constant (conic constant), and "Am" is an aspherical coefficient of order m, it is defined by the following equation.
zd = ch ² / (1 + (1- (1 + κ) c ² h ² ) ^1/2 ) + ΣAm × h ^m
Note that Σ indicates the sum of m.

In the lens data table, the material that forms the lens may be shown in association with the surface number on the object side.

In addition, a table of specification data of the lens system of each example and reference example is attached. In the table of specification data, "f" indicates the focal length. "Fno" indicates an F number. “Ω” indicates a half angle of view (maximum half angle of view). "Y" indicates the maximum image height. "TT" indicates the total optical length at the time of focusing. "Dex" indicates the exit pupil distance.

In the table of lens data and lens system specification data, "degree" is used as the unit of angle, and "mm" is used as the unit of length. However, since the lens system can be used even if it is proportionally expanded or contracted, any other unit can be used.

When the lens system is mounted on the image pickup apparatus as an image pickup lens, it is preferable to include various filters such as a low-pass filter according to the specifications of the image pickup apparatus and optical elements such as a protective cover glass. However, as the lens system, a form having or not having such an optical element can be adopted. It can be said that a lens system having such an optical element and a lens system not having an optical element are equivalent lens systems.

"Gi" indicates a lens group. In "Gi", i following the letter G is a natural number for the purpose of identifying the lens group included in the lens system in each Example and Reference Example. The lens group comprises one or more lenses. In the description of each Example and Reference Example, it means that the lens group to which the symbol Gi is assigned and the lens group to which the same symbol Gi is assigned in the other Examples and Reference Examples are lens groups having the same lens configuration. It's not something to do. "Lj" indicates one lens. In "Lj", j following the letter L is a natural number for the purpose of identifying the lens included in the lens system in each embodiment and reference example. In the description of each Example and Reference Example, it does not mean that the lens to which the symbol Lj is assigned and the lens to which the same symbol Lj is assigned in the other Examples and Reference Examples are the same lens.

Examples of the lens system according to the present invention are disclosed in connection with FIGS. 1 to 6. As disclosed in the first to third embodiments, the lens system of one embodiment includes a first lens group, an aperture diaphragm, and a second lens group in order from the object side. The first lens group includes a first lens having the most negative refractive power on the object side, and at least one lens having a positive refractive power on the image plane side of the first lens. The second lens group includes a lens having a positive refractive power, a lens having a negative refractive power, and a lens having a positive refractive power in order from the object side, and a lens having aspherical surfaces on both sides on the most image plane side. Prepare. Assuming that the focal length of the lens on the most object side is f1, the focal length of the entire system is f, and the focal length of the lens on the image plane side is fL, the conditional expression 1.00 << | f1 | / f <4.00.・ ・ (1)
-0.2 <f / fL <0.2 ... (2)
To be satisfied.

By arranging the first lens having the most negative refractive power on the object side, the entrance pupil can be brought to the object side, so that the diameter of the first lens can be suppressed while widening the angle. By arranging a lens having a positive refractive power in the first lens group, it is possible to correct distortion and chromatic aberration of magnification generated by the first lens having a negative refractive power. The occurrence of spherical aberration can be suppressed by having a configuration in the second lens group, which is a lens having a positive refractive power, a lens having a negative refractive power, and a lens having a positive refractive power in order from the object side. .. By arranging a lens having aspherical surfaces on both sides on the most image plane side, it is possible to correct distortion and astigmatism generated by the first lens.

Conditional expression (1) defines the relationship between the absolute value of the focal length of the lens on the most object side and the focal length of the entire system. When the upper limit of the conditional equation (1) is exceeded, the refractive power of the lens on the object side becomes weaker and the entrance pupil position is located closer to the image plane side, so that the lens on the object side cannot be miniaturized. .. On the other hand, when the value is below the lower limit of the conditional expression (1), the refractive power of the lens on the object side becomes too strong, so that distortion and chromatic aberration of magnification occur in the lens on the object side, which makes it difficult to improve the performance. Become.

Further, the above-mentioned effect becomes more remarkable by satisfying the following conditional expression (1-1).
1.1 <| f1 | / f <3.0 ... (1-1)

Further, the above-mentioned effect becomes more remarkable by satisfying the following conditional expression (1-2).
1.2 <| f1 | / f <2.5 ... (1-2)

Conditional expression (2) defines the relationship between the focal length of the lens closest to the image plane and the focal length of the entire system. When the upper limit of the conditional expression (2) or more is exceeded, the positive refractive power of the lens on the image plane side becomes stronger, spherical aberration occurs, and it becomes difficult to improve the performance. On the other hand, when it becomes less than the lower limit of the conditional expression, the negative refractive power of the lens on the image plane side becomes stronger, spherical aberration occurs, and it becomes difficult to improve the performance. Further, the above-mentioned effect becomes more remarkable by satisfying the following conditional expression (2-1).
-0.10 <f / fL <0.10 ... (2-1)

Further, the above-mentioned effect becomes more remarkable by satisfying the following conditional expression (2-2).
-0.07 <f / fL <0.07 ... (2-2)

The lens on the image plane side has a convex shape on both the R1 and R2 planes at the center, and has an inflection point once up to the peripheral portion, and the peripheral portion has a concave shape on the object side. good. As a result, astigmatism can be corrected without aggravating spherical aberration.

The focal length of the first lens group is f_1G, the conditional expression 1.5 / f_1G / f <10 ... (3)
May be satisfied.

Conditional expression (3) defines the relationship between the focal length of the first lens group and the focal length of the entire system. If it exceeds the upper limit of the conditional expression (3), the refractive power of the first lens group becomes weak and the total length becomes large, so that the size cannot be reduced. On the other hand, when it becomes less than the lower limit of the conditional equation (3), the refractive power of the first lens group becomes too strong, so astigmatism and spherical aberration occur in the first lens group, and it becomes difficult to improve the performance. ..

Further, the above-mentioned effect becomes more remarkable by satisfying the following conditional expression (3-1).
2.0 <f_1G | / f <8.0 ... (3-1)

Conditional expression 1.5 / f_2G / f <5.0 ... (4), where the focal length of the second lens group is f_2G.
May be satisfied.

The conditional expression (4) defines the relationship between the focal length of the second lens group and the focal length of the entire system. If it exceeds the upper limit of the conditional expression (4), the refractive power of the second lens group becomes weak and the total length becomes large, so that the size cannot be reduced. On the other hand, when it becomes less than the lower limit of the conditional equation (4), the refractive power of the second lens group becomes too strong, so astigmatism and spherical aberration occur in the second lens group, and it becomes difficult to improve the performance. ..

Further, the above-mentioned effect becomes more remarkable by satisfying the following conditional expression (4-1).
2.0 <f_2G | / f <3.5 ... (4-1)

Of the positive refractive power lens, the negative refractive power lens, and the positive refractive power lens provided by the second lens group in order from the object side, the lens having the positive refractive power on the object side. The focal distance of is f_p1, and the focal distance of the lens having a positive refractive power on the image plane side is f_p2, and the conditional equation 1.3 <f_p1 / f <2.6 ... (5).
1.1 <f_p2 / f <5.0 ... (6)
May be satisfied.

The conditional expression (5) is a positive refractive power on the object side in a lens having a positive refractive power, a lens having a negative refractive power, and a lens having a positive refractive power, which the second lens group has in order from the object side. It defines the relationship between the focal length of a lens having a lens and the focal length of the entire system. When the upper limit of the conditional expression (5) or more is exceeded, the refractive power of the lens having a positive refractive power on the object side in the second lens group becomes weak and the total length becomes large, so that the size cannot be reduced. On the other hand, when the value is equal to or less than the lower limit of the conditional equation (5), the refractive power of the lens having a positive refractive power on the object side becomes too strong in the second lens group, so that astigmatism and spherical aberration occur in the second lens group. Therefore, it becomes difficult to improve the performance.

Further, the above-mentioned effect becomes more remarkable by satisfying the following conditional expression (5-1).
1.50 <f_p1 / f <2.30 ... (5-1)

The conditional expression (6) is a positive refractive power on the image plane side in a lens having a positive refractive power, a lens having a negative refractive power, and a lens having a positive refractive power, which the second lens group has in order from the object side. It defines the relationship between the focal length of a lens having a lens and the focal length of the entire system. When the upper limit of the conditional expression (6) is exceeded, the refractive power of the lens having a positive refractive power on the image plane side in the second lens group becomes weak and the total length becomes large, so that the size cannot be reduced. On the other hand, when the value is equal to or less than the lower limit of the conditional equation (6), the refractive power of the lens having a positive refractive power on the image plane side becomes too strong in the second lens group, so that astigmatism and spherical aberration occur in the second lens group. It will occur and it will be difficult to improve the performance.

Further, the above-mentioned effect becomes more remarkable by satisfying the following conditional expression (6-1).
1.30 <f_p2 / f <4.50 ... (6-1)

Conditional expression 2.7 <TTL / Y <3, where the distance on the optical axis from the lens surface on the most object side of the first lens group when the object is in focus at infinity is TTL and the maximum image height is Y. .6 ・ ・ ・ (7)
May be satisfied.

Conditional expression (7) defines the relationship between the distance on the optical axis from the lens surface on the most object side of the first lens group to the image plane when the object is in focus at infinity and the maximum image height. When the upper limit of the conditional expression (7) is exceeded, the distance on the optical axis from the lens surface on the most object side of the first lens group at the time of focusing on an object at infinity is long with respect to the maximum image height, and the lens is lensed. The diameter becomes large. On the other hand, when the value is equal to or less than the lower limit of the conditional equation (7), the distance on the optical axis from the lens surface on the most object side of the first lens group to the image plane when the object is in focus at infinity is short with respect to the maximum image height. As a result, the number of lenses with a shorter focal length increases, making it difficult to correct spherical aberration.

Further, the above-mentioned effect becomes more remarkable by satisfying the following conditional expression (7-1).
2.9 <TTL / Y <3.4 ... (7-1)

Conditional expression 1.2 <L_sto / Y <2.0 ... (8), where the distance on the optical axis from the aperture stop to the image plane is L_sho and the maximum image height is Y.
May be satisfied.

The conditional expression (8) defines the relationship between the distance on the optical axis from the aperture stop to the image plane and the maximum image height. When the upper limit of the conditional expression (8) is exceeded, the distance on the optical axis from the aperture diaphragm to the image plane becomes longer with respect to the maximum image height, and the total lens length cannot be reduced. On the other hand, when the lower limit of the conditional equation (8) is exceeded, the distance on the optical axis from the aperture stop to the image plane becomes shorter with respect to the maximum image height, and the focal length becomes shorter in the second lens group. Therefore, it becomes difficult to correct spherical aberration.

Further, the above-mentioned effect becomes more remarkable by satisfying the following conditional expression (8-1).
1.4 <L_sto / Y <1.8 ... (8-1)

Conditional expression 23.0 <v1 <42.0 ... (9), where v1 is the Abbe number of the lens having a positive refractive power of the first lens group.
May be satisfied.

The conditional expression (9) defines the Abbe number of the lens having a positive refractive power of the first lens group. When the upper limit of the conditional equation (9) is reached, the Abbe number of the lens having a positive refractive power of the first lens group becomes large and the dispersion becomes too weak, so that the chromatic aberration of magnification generated in the first lens can be corrected. Can not. On the other hand, when the value is equal to or less than the lower limit of the conditional equation (9), the Abbe number of the lens having a positive refractive power of the first lens group is not small, the dispersion becomes too strong, and axial chromatic aberration occurs.

Further, the above-mentioned effect becomes more remarkable by satisfying the following conditional expression (9-1).
29.9 <v1 <38.0 ... (9-1)

Conditional expression -1.6 <fn / f <-0.8 ... (10), where the combined focal length of the lens on the object side of the lens having the positive refractive power of the first lens group is fn.
May be satisfied.

Conditional expression (10) defines the relationship between the combined focal length of the lens on the object side of the lens having the positive refractive power of the first lens group and the focal length of the entire system. When the upper limit of the conditional equation (10) is exceeded, the combined focal length of the lens on the object side becomes longer than that of the lens having a positive refractive power of the first lens group, and the entrance pupil position is located closer to the image plane side. Therefore, the lens diameter of the first lens group cannot be reduced. On the other hand, when the value is equal to or less than the lower limit of the conditional equation (10), the combined focal length of the lens on the object side is too short compared to the lens having a positive refractive power of the first lens group, so that distortion and chromatic aberration of magnification occur. Therefore, it becomes difficult to improve the performance.

Further, the above-mentioned effect becomes more remarkable by satisfying the following conditional expression (10-1).
-1.4 <fn / f <-0.9 ... (10-1)

The first lens group may include three or more consecutively adjacent glass lens groups in order from the object side. The second lens group may include four or more consecutive adjacent plastic lenses.

According to the above lens system, it is possible to provide a high-performance lens system having a short optical total length including back focus and a small lens diameter.

FIG. 1 shows the lens configuration of the lens system 100 in the first embodiment together with the optical member P and the image plane IM.

The lens system 100 is composed of a first lens group G1 having a positive refractive power, an aperture stop S, and a second lens group G2 having a positive refractive power in order from the object side. The first lens group G1 has an aspherical negative meniscus lens L1 having a convex surface facing the object side, an aspherical negative meniscus lens L2 having a convex surface facing the object side, and a biconvex shape in order from the object side. It is composed of a positive lens L3 and a junction lens of a negative meniscus lens L4 having a convex surface facing the image plane side. In the first lens group G1, the negative refractive power required for wide-angle lens sharing is shared by at least two negative components, whereby off-axis aberrations are satisfactorily corrected. The positive junction lens of the first lens group G1 corrects the chromatic aberration of magnification while suppressing the occurrence of axial chromatic aberration.

The second lens group G2 includes a biconvex aspherical positive lens L5, a biconcave aspherical negative lens L6, and an aspherical positive lens L6 having a convex surface facing the image plane side, in order from the object side. It is composed of a meniscus lens L7, an aspherical negative meniscus lens L8 having a convex surface facing the image plane side, and an aspherical positive lens L9 having a convex shape toward the object side near the optical axis. By frequently using aspherical lenses in the second lens group G2, spherical aberration and astigmatism can be corrected.

Table 1 shows the lens data of the lens system 100. Table 2 is a table showing the aspherical surface data of the lens system 100.

Table 3 is a table of specification data showing the focal length f, the F number Fno, the half angle of view ω, the image height Y, and the optical total length TT when focusing on the infinity subject of the lens system 100.

FIG. 2 shows spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the lens system 100 in a state of being in focus on an infinity subject. In spherical aberration, the alternate long and short dash line indicates the value of the C line (656.27 nm), the solid line indicates the value of the d line (587.56 nm), and the broken line indicates the value of the g line (435.84 nm). In astigmatism, the solid line shows the value of the sagittal image plane of the d line, and the alternate long and short dash line shows the value of the meridional image plane of the d line. In distortion, the solid line indicates the value of the d line. In the chromatic aberration of magnification, the solid line shows the value of the C line (656.27 nm), and the broken line shows the value of the g line (435.84 nm). From each aberration diagram, it is clear that the lens system 100 has various aberrations corrected well and has excellent imaging performance.

FIG. 3 shows the lens configuration of the lens system 200 in the second embodiment together with the optical member P and the image plane IM.

The lens system 200 is composed of a first lens group G1 having a positive refractive power, an aperture stop S, and a second lens group G2 having a positive refractive power in order from the object side. The first lens group G1 includes an aspherical negative meniscus lens L1 having a convex surface facing the object side, an aspherical negative meniscus lens L2 having a convex surface facing the object side, a biconvex positive lens L3, and an image. It is composed of a junction lens of a negative meniscus lens L4 with a convex surface facing the surface side. In the lens system 200, off-axis aberrations are satisfactorily corrected by sharing the negative refractive power required for wide-angle lensing with at least two negative components. The positive junction lens of the first lens group G1 corrects the chromatic aberration of magnification while suppressing the occurrence of axial chromatic aberration.

The second lens group G2 includes a biconvex aspherical positive lens L5, a biconcave aspherical negative lens L6, and an aspherical positive meniscus lens L7 with the convex surface facing the image plane side. It is composed of an aspherical negative meniscus lens L8 having a convex surface facing the image plane side and an aspherical positive lens L9 having a convex shape toward the object side near the optical axis. By using a large number of aspherical lenses in the second lens group G2, spherical aberration and astigmatism can be corrected.

Table 4 shows the lens data of the lens system 200. Table 5 is a table showing the aspherical surface data of the lens system 200.

Table 6 is a table of specification data showing the focal length f, the F number Fno, the half angle of view ω, the image height Y, and the optical total length TT when focusing on the infinity subject of the lens system 200.

FIG. 4 shows spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the lens system 200 in a state of being in focus on an infinity subject. In spherical aberration, the alternate long and short dash line indicates the value of the C line (656.27 nm), the solid line indicates the value of the d line (587.56 nm), and the broken line indicates the value of the g line (435.84 nm). In astigmatism, the solid line shows the value of the sagittal image plane of the d line, and the alternate long and short dash line shows the value of the meridional image plane of the d line. In distortion, the solid line indicates the value of the d line. In the chromatic aberration of magnification, the solid line shows the value of the C line (656.27 nm), and the broken line shows the value of the g line (435.84 nm). From each aberration diagram, it is clear that the lens system 200 has various aberrations corrected well and has excellent imaging performance.

FIG. 5 shows the lens configuration of the lens system 300 in the third embodiment together with the optical member P and the image plane IM.

The lens system 300 is composed of a first lens group G1 having a positive refractive power, an aperture stop S, and a second lens group G2 having a positive refractive power in order from the object side. The first lens group G1 is composed of an aspherical negative meniscus lens L1 having a convex surface facing the object side and a biconvex aspherical positive lens L2. The positive lens L2 corrects the chromatic aberration of magnification.

The second lens group G2 includes a positive meniscus lens L3 with a convex surface facing the image plane side, a biconvex aspherical positive lens L4, a biconcave aspherical negative lens L5, and biconvex. It is composed of an aspherical positive meniscus lens L6 and an aspherical positive lens L7 having a convex shape toward an object near the optical axis. By frequently using aspherical lenses in the second lens group G2, spherical aberration and astigmatism can be corrected.

Table 7 shows the lens data of the lens system 300. Table 8 is a table showing the aspherical surface data of the lens system 300.

Table 9 is a table of specification data showing the focal length f, the F number Fno, the half angle of view ω, the image height Y, and the optical total length TT when focusing on the infinity subject of the lens system 300.

FIG. 6 shows spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the lens system 300 in a state of being in focus on an infinity subject. In spherical aberration, the alternate long and short dash line indicates the value of the C line (656.27 nm), the solid line indicates the value of the d line (587.56 nm), and the broken line indicates the value of the g line (435.84 nm). In astigmatism, the solid line shows the value of the sagittal image plane of the d line, and the alternate long and short dash line shows the value of the meridional image plane of the d line. In distortion, the solid line indicates the value of the d line. In the chromatic aberration of magnification, the solid line shows the value of the C line (656.27 nm), and the broken line shows the value of the g line (435.84 nm). From each aberration diagram, it is clear that the lens system 300 has various aberrations corrected well and has excellent imaging performance.

Table 10 shows the numerical values calculated by the mathematical formulas (1) to (10) in the lens system of the first to third embodiments.

The configuration provided in the above-mentioned lens system can be any combination, and can be appropriately selectively adopted according to the required specifications. For example, the lens system according to the above embodiment has conditional expressions (1) to (10), (1-1), (1-2), (2-1), (3-1), (4-1), ( It is assumed that 5-1), (6-1), (7-1), (8-1), (9-1) and (10-1) are satisfied, but conditional expressions (1) to (10) are satisfied. ), (1-1), (1-2), (2-1), (3-1), (4-1), (5-1), (6-1), (7-1), It may satisfy any one of (8-1), (9-1) and (10-1)), and may satisfy any combination of these conditional expressions. ..

As described above, according to the lens configuration provided in the lens systems according to the first to third embodiments, the total optical length including the back focus is used as a lens system having a relatively wide angle and a large image circle. It is possible to provide a high-performance lens system having a short lens diameter and a small lens diameter.

It is desirable that the lens system for imaging has a small size (the overall length is short and the lens diameter is small) and has high performance (that various aberrations are well corrected) that can handle high resolution. ing. The image pickup lens described in Patent Document 1 has only a lens having a positive refractive power, a lens having a negative refractive power, and a lens having a positive refractive power arranged on the image plane side of the aperture diaphragm. , Astigmatism cannot be sufficiently corrected when trying to support an imaging format of a larger size. In the image pickup lens described in Patent Document 2, a lens having a positive refractive power, a lens having a negative refractive power, a lens having a positive refractive power, and an aspherical lens are arranged on the image plane side of the aperture aperture. Although it is possible to correct the non-point aberration to some extent, the refractive power of the first lens, which has a negative refractive power with respect to the focal distance of the entire system, is weak, so it is possible to use a larger size imaging format. The diameter of the first lens cannot be reduced when trying to cope with it. On the other hand, according to the lens system according to the above embodiment, the problem can be alleviated.

Next, an embodiment of the first invention will be described with reference to FIGS. 7 to 12, using examples of the lens system according to the first invention as a reference example. The lens system according to the other first invention may have the configurations described in the following items A1 to A5.

[Item A1]
A positive first lens group, an aperture diaphragm, and a positive second lens group are provided in order from the object side to the image side.
The first lens group and the second lens group are composed of seven or more lenses in total.
The first lens group includes three or less glass glass lenses.
The second lens group includes a lens composed of a surface having two inflection points from the center of the optical axis to the peripheral portion on the most image plane side.
The second lens group is composed entirely of plastic glass lenses.
The focal length of the first lens group is fg1, the focal length of the second lens group is fg2, and the focal length of the first lens group is on the optical axis from the lens surface to the image plane on the most object side of the first lens group when the object is in focus at infinity. The condition formula 0 <fg1 / fg2 <5, where the distance is TTL, the maximum image height is Y, the maximum half angle of view is HFOV, and the distance from the ejection pupil to the image plane is EPD.
1.95 <TTL / Y <3.8
TAN (HFOV)> 1.75
2.5 <EPD <15
A lens system that satisfies.
[Item A2]
The lens system according to item A1, wherein the second lens group includes a positive lens having a surface having at least one inflection point from the center of the optical axis to the peripheral portion on the most image plane side.
[Item A3]
Let fL be the focal length of the lens on the image side of the second lens group, and f be the focal length of the entire lens system.
Conditional expression | fL / f |> 4.8
The lens system according to item A1 or item A2 that satisfies the above.
[Item A4]
Conditional expression 1 <fg1 / f <10, where the focal length of the first lens group is fg1, the focal length of the second lens group is fg2, and the focal length of the entire lens system is f.
1.8 <fg2 / f <5
The lens system according to any one of items A1 to A3, which satisfies the above.
[Item A5]
The focal length of the positive lens arranged on the image side of the first lens group is fg1p, the focal length of the positive lens arranged on the object side of the second lens group is fg2p, and the focal length of the first lens group is fg2p. Is fg1, and the focal length of the second lens group is fg2, and the conditional expression 0.15 <fg1p / fg1 <0.9.
0.3 <fg2p / fg2 <1.3
The lens system according to any one of items A1 to A4, which satisfies the above.

As described above, the lens system may include a positive first lens group, an aperture diaphragm, and a positive second lens group in order from the object side to the image side. The first lens group and the second lens group may be composed of seven or more lenses in total. The first lens group may include three or less glass glass lenses. The second lens group may include a lens composed of a surface having two inflection points from the center of the optical axis to the peripheral portion on the most image plane side. The second lens group may be composed entirely of a plastic glass lens. The focal length of the first lens group is fg1, the focal length of the second lens group is fg2, and the distance on the optical axis from the lens surface on the most object side of the first lens group to the image plane when the object is in focus at infinity. Conditional expression 0 <fg1 / fg2 <5 ... (a1), where TTL, maximum image height is Y, maximum half angle of view is HFOV, and the distance from the ejection pupil to the image plane is EPD.
1.95 <TTL / Y <3.8 ... (a2)
TAN (HFOV)> 1.75 ... (a3)
2.5 <EPD <15 ... (a4)
May be satisfied.

By adopting the above configuration, it is possible to reduce the size of a lens that uses a large sensor size and has a wide angle of view while maintaining a shorter back focus with respect to the sensor size. Further, in a wide-angle lens, the lens diameter on the most object side of the first lens group tends to be very large, but by adopting the above configuration, the first lens group can maintain aberration performance and manufacturable robustness. The lens diameter on the object side can be made the smallest.

The conditional expression (a1) defines the ratio of the focal lengths of the first lens group and the second lens group. Generally, in the case of a wide-angle lens, the power of the first lens group is lower than the power of the second lens group because a light ray having a wide angle of view is incident, and the first lens group has a negative power. However, in the case of a fixed focus type lens, it is necessary to improve environmental reliability such as focus shift due to temperature change, and in the case of a wide-angle and compact lens with strong power such as the lens system having the above configuration, the conditional expression (a1) ) Is desirable.

The conditional expression (a2) defines the ratio between the total length and the image height. When it becomes less than the lower limit of the conditional expression (a2), the angle of incidence on the sensor becomes large and it becomes difficult to maintain the peripheral light amount. Further, although the entire system of the lens can be made smaller, the manufacturing sensitivity becomes very high and the manufacturing becomes difficult. On the other hand, when the upper limit of the conditional expression (a2) is exceeded, the total length of the entire lens becomes larger than the sensor size, the manufacturing difficulty is lowered and it is advantageous for aberration correction, but the size can be reduced to near the manufacturing limit. It will not be easy.

Further, by satisfying the conditional expression (a2-1), the above-mentioned effect becomes more remarkable.
2 <TTL / Y <3 ... (a2-1)

The conditional expression (a3) defines the angle of view. By satisfying the conditional expression (a3), a wider-angle lens configuration can be realized.

The conditional expression (a4) defines the distance between the exit pupil and the image plane. When it becomes less than the lower limit of the conditional expression (a4), it is not possible to maintain an appropriate angle of incidence on the image sensor. On the other hand, if it exceeds the upper limit of the conditional expression (a4), it does not contribute to the miniaturization of the lens.

The second lens group may be provided with a positive lens having a surface having at least one inflection point from the center of the optical axis to the peripheral portion on the most image plane side.

Conditional expression | fL / f |> 4.8 ... (a5), where fL is the focal length of the lens on the image side of the second lens group and f is the focal length of the entire lens system.
May be satisfied.

The conditional expression (a5) defines the ratio of the refractive power of the entire lens system to the refractive power of the lens on the image side of the second lens group. When it becomes less than the lower limit of this conditional expression, the refractive power of the lens on the image side of the second lens group becomes large. If the entire lens system is miniaturized, the lens on the image side of the second lens group approaches the image plane, and the volume tends to increase in order to avoid this. Further, if the refractive power of the lens on the image side of the second lens group is large, it fluctuates greatly when the environment changes, and the environmental reliability becomes low. Therefore, it is desirable to satisfy the conditional expression (a5).

Further, the above-mentioned effect becomes more remarkable by satisfying the following conditional expression (a5-1).
｜ fL / f ｜ ＞ 20 ・ ・ ・ (a5-1)

Conditional expression 1 <fg1 / f <10 ... (a6), where the focal length of the first lens group is fg1, the focal length of the second lens group is fg2, and the focal length of the entire lens system is f.
1.8 <fg2 / f <5 ... (a7)
May be satisfied.

The conditional expression (a6) defines the ratio of the refractive power of the first lens group to the entire lens system. When the value is equal to or less than the lower limit of the conditional expression (a6), the refractive power of the first lens group becomes relatively strong, which contributes to miniaturization but makes it difficult to correct off-axis aberrations. On the other hand, when the upper limit of the conditional equation (a6) is exceeded, the refractive power of the first lens group becomes relatively small, and the focus change generated on the second lens group side composed of the plastic lens when the environment changes is absorbed. It becomes difficult.

The conditional expression (a7) defines the ratio of the refractive power of the second lens group to the entire lens system. When the value is equal to or less than the lower limit of the conditional expression (a7), the refractive power of the second lens group composed of the plastic lens becomes relatively strong, and the focus change becomes large when the environment changes. On the other hand, when the upper limit of the conditional expression (a7) is exceeded, the refractive power of the second lens group becomes relatively small, and it becomes necessary to give the first lens group a refractive power, so that it is difficult to correct off-axis aberrations. Become.

The focal length of the positive lens placed on the image side of the first lens group is fg1p, the focal length of the positive lens placed on the object side of the second lens group is fg2p, and the focal length of the first lens group is fg1. Assuming that the focal length of the second lens group is fg2, the conditional expression 0.15 <fg1p / fg1 <0.9 ... (a8)
0.3 <fg2p / fg2 <1.3 ... (a9)
May be satisfied.

The conditional equation (a8) defines the ratio between the focal length of the positive lens arranged on the image side of the first lens group and the focal length of the first lens group. When it becomes less than the lower limit of the conditional equation (a8), it is advantageous for reliability at the time of environmental change such as focus shift at the time of temperature change, but it is arranged on the image side of the first lens group with respect to the refractive power of the first lens group. Since the ratio of the refractive power of the positive lens is increased, it becomes difficult to correct the off-axis aberration, and the aberration performance tends to deteriorate. On the other hand, if it exceeds the upper limit of this conditional expression (a8), the reliability at the time of environmental change tends to be low.

Further, by satisfying the conditional expression (a8-1), the above-mentioned effect becomes more remarkable.
0.2 <fg1p / fg1 <0.65 ... (a8-1)

The conditional equation (a9) defines the ratio between the focal length of the positive lens arranged on the closest object side of the second lens group and the focal length of the second lens group. When the value exceeds the lower limit of the conditional equation (a9), the refractive power of the positive lens arranged on the most object side of the second lens group becomes relatively large, and the balance of the refractive power in the second lens group tends to be lost, resulting in aberration. Performance tends to deteriorate. On the other hand, when the upper limit of the conditional expression (a9) is exceeded, the reliability at the time of environmental change tends to be low.

Further, by satisfying the conditional expression (a9-1), the above-mentioned effect becomes more remarkable.
0.35 <fg2p / fg2 <0.8 ... (a9-1)

As described above, according to another embodiment of the first invention, the image circle is large and the total optical length including the back focus is small, but the influence on environmental changes is small. It is possible to provide a photographing lens having high optical performance.

FIG. 7 shows the lens configuration of the lens system 400 in the first reference example together with the optical member P and the image plane IM. The lens system 400 is composed of a first lens group G1 having a positive refractive power, an aperture stop S, and a second lens group G2 having a positive refractive power in order from the object side.

The first lens group G1 is composed of two negative glass aspherical meniscus lenses L1 and L2 having concave surfaces facing the image side and a biconvex glass spherical lens L3 in total, in order from the object side. .. With this configuration, in an optical system with a small total lens length, the two lenses preceded by a negative component can satisfactorily correct off-axis aberrations of high FOV rays, and a positive biconvex spherical lens near the aperture aperture. By arranging L3, spherical aberration can be corrected and environmental reliability can be improved.

The second lens group G2 includes a positive meniscus aspherical lens L4 with a convex surface facing the image side, a biconcave negative aspherical lens L5, a biconvex positive aspherical lens L6, and an object side. It is composed of a total of four lenses with a positive aspherical lens L7 in the paraxial region with the concave surface facing the convex surface and the concave surface.

Plastic glass material with a relatively high Abbe number is used for the first and third biconvex positive aspherical lenses L4 and L6 from the object side in the second lens group G2, and the negative non-concave shape is used. By using a plastic glass material having a low Abbe number for the spherical lens L5, it is possible to appropriately correct aberrations for each angle beam and to correct axial aberrations, off-axis aberrations, and chromatic aberration of magnification in a good balance. The aspherical lens L7 on the image plane side is the lens having the largest lens diameter in the second lens group, has a low refractive power with respect to the entire system refractive power, and has at least 1 from the center of the optical axis to the peripheral portion. Has a turning point of times. As a result, the environmental reliability is improved, and the curvature of field is appropriately corrected by the aspherical shape having the above-mentioned inflection point.

Table 11 shows the lens data of the lens system 400 . Table 12 is a table showing the aspherical surface data of the lens system 400 .

Table 13 is a table of specification data showing the focal length f, F number Fno, half angle of view ω, image height Y, and exit pupil distance Dex of the entire system when focusing on an infinity subject of the lens system 400 . ..

FIG. 8 shows spherical aberration, astigmatism, and distortion in a state of being in focus on an infinity subject of the lens system 400 . In spherical aberration, the alternate long and short dash line indicates the value of the C line (656.27 nm), the solid line indicates the value of the d line (587.56 nm), and the broken line indicates the value of the g line (435.84 nm). In astigmatism, the solid line shows the value of the sagittal image plane of the d line, and the broken line shows the value of the meridional image plane of the d line. In distortion, the solid line indicates the value of the d line. From each aberration diagram, it is clear that the lens system 400 has various aberrations corrected well and has excellent imaging performance.

FIG. 9 shows the lens configuration of the lens system 500 in the second reference example together with the optical member P and the image plane IM. The lens system 500 is composed of a first lens group G1 having a positive refractive power, an aperture stop S, and a second lens group G2 having a positive refractive power in order from the object side.

The first lens group G1 is a negative glass aspherical lens L1 that is biconcave in the paraxial region and has a convex surface toward the object side, and a negative glass aspherical meniscus lens L2 that has a concave surface facing the image side in order from the object side. And a biconvex glass spherical lens L3, a total of three lenses. In addition to arranging the negative component in advance, this lens configuration makes it possible to satisfactorily correct spherical aberration and off-axis aberration in an optical system having a small lens diameter. Further, by using the negative meniscus lens L2 having a convex surface facing the object side second from the object side, the declination angle of the high FOB light beam is reduced and the occurrence of aberration is suppressed. Further, by arranging the positive biconvex spherical lens L3 at a position close to the aperture stop S, spherical aberration can be corrected and environmental reliability can be improved.

The second lens group G2 includes a positive meniscus aspherical lens L4 having a convex surface facing the image side, a negative aspherical meniscus lens L5 having a biconcave shape, and a positive meniscus aspherical lens L6 having a convex surface facing the image side. A negative aspherical lens L7 in the near-axis region with the concave surface on the object side and the convex surface on the image side surface, and a positive aspherical lens L8 in the near-axis region with the convex surface on the object side and the concave surface on the image side surface. It consists of a total of 5 sheets.

Plastic glass material with a relatively high Abbe number is used for the first and third biconvex positive aspherical lenses L4 and L6 from the object side in the second lens G2 group, and the biconcave negative non-spherical lens is used. By using a plastic glass material with a low Abbe number for the spherical meniscus lens L5, aberration correction can be appropriately performed for each angle beam, and axial aberration, aspherical aberration, and magnification chromatic aberration can be corrected in a good balance. ..

Further, the two aspherical lenses L7 and L8 arranged on the image plane side are the two lenses having the largest lens diameter in the second lens group, have a low refractive power with respect to the entire system refractive power, and have optical power. It has a surface with at least one turning point from the center of the axis to the peripheral part. As a result, the environmental reliability is improved, and the curvature of field and other off-axis aberrations are appropriately corrected by the aspherical shape having the above-mentioned inflection point.

Table 14 shows the lens data of the lens system 500 . Tables 15A and 15B are tables showing aspherical data of the lens system 400 .

Table 16 is a table of specification data showing the focal length f, F number Fno, half angle of view ω, image height Y, and exit pupil distance Dex of the entire system when focusing on an infinity subject of the lens system 500 . ..

FIG. 10 shows spherical aberration, astigmatism, and distortion in a state where the lens system 500 is focused on an infinity subject. In spherical aberration, the alternate long and short dash line indicates the value of the C line (656.27 nm), the solid line indicates the value of the d line (587.56 nm), and the broken line indicates the value of the g line (435.84 nm). In astigmatism, the solid line shows the value of the sagittal image plane of the d line, and the broken line shows the value of the meridional image plane of the d line. In the distortion aberration, the solid line shows the value of the d line. From each aberration diagram, it is clear that the lens system 500 has various aberrations corrected well and has excellent imaging performance.

FIG. 11 shows the lens configuration of the lens system 600 in the third reference example together with the optical member P and the image plane IM. The lens system 600 is composed of a first lens group G1 having a positive refractive power, an aperture diaphragm S, and a second lens group G2 having a positive refractive power in order from the object side.

The first lens group G1 is composed of two negative glass aspherical meniscus lenses L1 and L2 having concave surfaces facing the image side and a biconvex glass spherical lens L3 in total, in order from the object side. .. With this configuration, in an optical system with a small total lens length, the two lenses with the leading negative component satisfactorily correct the off-axis aberrations of high FOV rays, and a positive biconvex spherical lens L3 is placed near the aperture. By arranging the lens, spherical aberration can be corrected and environmental reliability can be improved. Further, by using the negative meniscus lens L2 facing the convex surface toward the object side as the second lens from the object side, the declination angle of the high FOB light ray is reduced and the occurrence of aberration is suppressed.

The second lens group G2 includes a biconvex positive aspherical lens L4, a biconcave negative aspherical lens L5, a biconvex positive aspherical lens L6, and a convex / image side surface on the object side. It is composed of a total of four lenses with a positive aspherical lens L7 in the paraxial region with the concave surface facing. Plastic glass material with a relatively high Abbe number is used for the first and third biconvex positive aspherical lenses L4 and L6 from the object side in the second lens group G2, and the negative non-concave shape is used. By using a plastic glass material with a low Abbe number for the spherical lens L7, it is possible to appropriately correct aberrations for each angle beam and to correct axial aberrations, off-axis aberrations, and chromatic aberration of magnification in a good balance. ..

The aspherical lens L7 arranged on the image plane side is a lens having the largest lens diameter in the second lens group, has a low refractive power with respect to the entire system refractive power, and has at least a refractive power from the center of the optical axis to the peripheral portion. It has a surface with one turning point. As a result, the environmental reliability is improved, and the curvature of field is appropriately corrected by the aspherical shape having the above-mentioned inflection point.

Table 17 shows the lens data of the lens system 600 . Table 18 is a table showing the aspherical surface data of the lens system 600.

Table 19 is a table of specification data showing the focal length f, F number Fno, half angle of view ω, image height Y, and exit pupil distance Dex of the entire system when focusing on an infinity subject of the lens system 600. be.

FIG. 12 shows spherical aberration, astigmatism, and distortion in a state of focusing on an infinity subject of the lens system 600. In spherical aberration, the alternate long and short dash line indicates the value of the C line (656.27 nm), the solid line indicates the value of the d line (587.56 nm), and the broken line indicates the value of the g line (435.84 nm). In astigmatism, the solid line shows the value of the sagittal image plane of the d line, and the broken line shows the value of the meridional image plane of the d line. In the distortion aberration, the solid line shows the value of the d line. From each aberration diagram, it is clear that the lens system 600 has various aberrations corrected well and has excellent imaging performance.

Table 20 shows the numerical values calculated by the mathematical formulas (a1) to (a9) in the lens system of the first reference example to the third reference example.

The configuration provided in the above-mentioned lens system can be any combination, and can be appropriately selectively adopted according to the required specifications. For example, the lens system according to the above reference example satisfies any one of the conditional expressions (a1) to (a9), (a2-1), (a5-1), (a8-1) and (a9-1). It may be any combination of these conditional expressions.

As described above, according to the lens configuration provided in the lens system according to the first reference example to the third reference example, the lens configuration has a large image circle and the total optical length including the back focus is small, but the environmental change. It is possible to provide a photographing lens having a high optical performance that has little influence on the subject.

As a lens system for an image pickup device, a large image size, a wide angle, a short front lens diameter and a short lens overall length, a small size of the entire system, and high optical performance are required. The following documents are disclosed as an image pickup lens.
[Patent Document 3] Japanese Patent No. 5045300 [Patent Document 4] Japanese Patent No. 6538201 [Patent Document 5] Japanese Patent No. 6626515 [Patent Document 6] US Patent Application Publication No. 2019/0250380

The lens of Example 1 described in Patent Document 3 has a relatively wide angle of FOV 155 °, but it is necessary to reduce the declination angle of the light beam by each lens in order to suppress the occurrence of aberration. When such an optical design is carried out, the lens on the most object side is generally designed with a lens having a diameter larger than that of the image circle, and the total length becomes long. For example, in Example 1 of Patent Document 3, the total length is 7 times or more the image height.

In Patent Document 4 and Patent Document 5, a plurality of glass aspherical lenses or plastic aspherical lenses are used in spite of having a relatively wide angle to suppress aberrations, and to prevent aberration deterioration and image formation position fluctuations due to environmental changes. It is said that the total volume was made relatively small by reducing the number of lenses while suppressing it. However, because a glass spherical lens is used for the lens on the most object side, the front lens diameter cannot be reduced and the total length is long. For example, in Example 1 of Patent Document 4, it can be seen that the total length is about four times or more the image height. Patent Document 5 discloses a configuration in which the first lens group has a negative refractive power, but when the total length is further shortened, the focus shift at the time of environmental change unless the first lens group has a refractive power. Cannot be corrected.

Patent Document 6 states that the FOV has a relatively wide angle of 120 to 146 °, and all plastic aspherical lenses are used to realize low profile and suppression of aberrations. For example, in Example 1 of Patent Document 3, since the image height is an optical system of 2.24 mm, the lens thickness is made thin by using all plastic lenses, the volume of the lens itself is small, and aberrations due to environmental fluctuations. It is said that deterioration and image position fluctuation are suppressed. However, when a larger FOV and image circle are required, the volume of the lens becomes large, so if the entire system is configured with only plastic lenses, there are problems that aberrations deteriorate due to environmental changes and the imaging position is more likely to fluctuate. There is. On the other hand, according to the lens system according to the embodiment described in relation to the above reference example, the problem can be alleviated.

Next, an embodiment of the second invention will be described with reference to FIGS. 13 to 18, using examples of the lens system according to the second invention as a reference example. The lens system according to the other second invention may have the configurations described in the following items B1 to B5.

[Item B1]
A first lens group on the object side of the diaphragm and a second lens group on the image plane side of the diaphragm are provided in order from the object side.
The first lens group has a negative power, and the second lens group has a positive power.
The first lens group is composed of two or more lenses, and a glass lens having aspherical surfaces on both sides having the most negative power on the object side is arranged in the first lens group.
The second lens group includes one positive glass lens and a plurality of resin lenses.
The negative glass lens on the most object side of the first lens group has the strongest negative power among the lenses included in the first lens group.
The positive glass lens in the second lens group has the strongest positive power among the lenses included in the second lens group.
The lens closest to the image plane has a convex shape on the object side near the optical axis and a convex shape on the image plane side with an inflection once as it moves away from the axis. It is an aspherical resin lens with
The distance from the ejection pupil to the image plane is Lexp, the diagonal image height is Y, the focal length of the negative glass lens on the most object side of the first lens group is f1 g, and the positive glass lens of the second lens group. With the focal length of f2g and the half angle of view in the diagonal direction as HFOV, the conditional expression | Lensp / Y | <1.25 ... (b1)
0.5 <| f2g / f1g | <1.5 ... (b2)
TAN (HFOV)> 2.5 ... (b3)
A lens system that satisfies.
[Item B2]
The first lens group includes a negative glass lens and a positive lens in order from the object side.
Conditional expression 1.5 <TTL / Y <3.2, where the distance from the object-side surface of the most object-side lens of the first lens group to the image pickup surface is TTL and the distance from the aperture to the image pickup surface is Lso. ... (b4)
0.5 <Lst o / TTL <0.85 ・ ・ ・ (b5)
The lens system according to item B1 that satisfies the above.
[Item B3]
The surface of the positive lens of the first lens group on the object side has a shape in which a convex is directed toward the object near the optical axis, and has at least one inflection point.
Conditional expression 0.5 <Tg2 / Y <1 ... (b6), where the center thickness of the second lens group is Tg2.
The lens system according to item B1 or item B2 that satisfies the above.
[Item B4]
Assuming that the focal length of the first lens group is f1, the focal length of the first lens group is f2, and the focal length of the entire system is f, the conditional equation 1.2 << | f1 / f | <4 ... (b7)
1.0 <| f2 / f | <3 ... (b8)
The lens system according to any one of items B1 to B3, which satisfies the above.
[Item B5]
Conditional expression 55 <Vg1 ... (B9), where the Abbe number of the glass lens included in the first lens group is Vg1 and the Abbe number of the glass lens included in the second lens group is Vg2.
55 <Vg2 ... (b10)
The lens system according to any one of items B1 to B4, which satisfies the above.

As described above, the lens system includes a first lens group on the object side of the diaphragm and a second lens group on the image plane side of the diaphragm in order from the object side. The first lens group may have a negative power and the second lens group may have a positive power. The first lens group is composed of two or more lenses, and a glass lens having aspherical surfaces on both sides may be arranged in the first lens group, which has the most negative power on the object side. The second lens group may include one positive glass lens and a plurality of resin lenses. The negative glass lens on the most object side of the first lens group may have the strongest negative power among the lenses included in the first lens group. The positive glass lens in the second lens group may have the strongest positive power among the lenses included in the second lens group. The lens closest to the image plane has a convex shape on the object side near the optical axis and a convex shape on the image plane side with an inflection once as it moves away from the axis. It may be an aspherical resin lens having. The distance from the ejection pupil to the image plane is Lexp, the diagonal image height is Y, the focal length of the negative glass lens on the most object side of the first lens group is f1 g, and the positive glass lens of the second lens group. With the focal length of f2g and the half angle of view in the diagonal direction as HFOV, the conditional expression | Lensp / Y | <1.25 ... (b1)
0.5 <| f2g / f1g | <1.5 ... (b2)
TAN (HFOV)> 2.5 ... (b3)
May be satisfied.

By adopting the above configuration, it is possible to reduce the size of a lens having a wide angle of view while maintaining a shorter back focus with respect to the sensor size. The lens on the most object side of the first lens group is a glass aspherical surface with negative power, one regular glass lens is placed in the second lens group, and each glass lens has the most power in each group. By arranging them so that they can be held, it is possible to achieve both miniaturization and high performance while strengthening the power of each group. Further, with such a configuration, it is possible to suppress performance deterioration due to environmental changes while maintaining miniaturization. Furthermore, the lens closest to the image plane has a convex shape toward the object near the optical axis on both the surface on the object side and the surface on the image plane side, and the shape changes to the image plane side once with an inflection as it moves away from the axis. By using an aspherical resin lens with a convex shape, it is possible to maintain high performance while shortening the ejection pupil distance.

The conditional expression (b1) defines the ratio between the exit pupil distance and the image height. When the upper limit of the conditional expression (b1) is exceeded, the total length of the entire lens becomes larger than the sensor size, and it becomes difficult to achieve both an ultra-wide angle and an extremely small size. Further, by satisfying the conditional expression (b2), the above-mentioned effect becomes more remarkable. When the upper limit of the conditional expression (b2) is exceeded, the power of the first lens group becomes too strong with respect to the second lens group, and it becomes difficult to maintain the peripheral performance. Further, when it becomes less than the lower limit of the conditional expression (b2), the negative power of the first lens group becomes too weak, and it becomes difficult to achieve both high performance and small diameter. The conditional expression (b3) shows an angle of view in which the effect is particularly remarkable.

The first lens group may include a negative glass lens and a positive lens in order from the object side. Conditional expression 1.5 <TTL / Y <3.2. The distance from the object-side surface of the lens on the most object-side of the first lens group to the image pickup surface is TTL, and the distance from the aperture to the image pickup surface is Lso.・ ・ (B4)
0.5 <Lst o / TTL <0.85 ・ ・ ・ (b5)
May be satisfied.

By forming the first lens group into two lenses, the first lens group can be made thinner, which contributes to both shortening of the optical total length and reduction of the front lens diameter. If the upper limit of the conditional expression (b4) is exceeded, the total length becomes too long for the sensor size, and miniaturization becomes difficult. On the other hand, when it becomes less than the lower limit of the conditional expression (b4), the total length becomes too short with respect to the sensor size, and it becomes difficult to secure robustness in manufacturing. When it becomes less than the lower limit of the conditional expression (b5), it becomes difficult to reduce the diameter of the front lens. On the other hand, when the upper limit of the conditional expression (b5) is exceeded, the thickness of the first lens group becomes too thin, and it becomes difficult to maintain the performance both on and off the axis.

The surface of the positive lens of the first lens group on the object side has a shape in which the surface on the object side is oriented toward the object near the optical axis, and may have at least one inflection point. Conditional expression 0.5 <Tg2 / Y <1 ... (b6), where the center thickness of the second lens group is Tg2.
May be satisfied.

By providing an inflection point on the surface of the positive lens of the first lens group on the object side as described above, it is possible to reduce the thickness of the positive lens of the first lens group and maintain the peripheral performance at the same time. When the upper limit of the conditional expression (b6) is exceeded, the thickness of the first lens group becomes too thick, and it becomes difficult to maintain the overall length reduction. On the other hand, when it becomes less than the lower limit of the conditional expression (b6), the positive lens of the first lens group becomes too thin, and it becomes difficult to maintain the peripheral performance.

Assuming that the focal length of the first lens group is f1, the focal length of the first lens group is f2, and the focal length of the entire system is f, the conditional equation 1.2 << | f1 / f | <4 ... (b7)
1.0 <| f2 / f | <3 ... (b8)
May be satisfied.

When the upper limit of the conditional expression (b7) is exceeded, the power of the first lens group becomes weak with respect to the angle of view, and it becomes difficult to reduce the diameter and shorten the total length. On the other hand, when it becomes less than the lower limit of the conditional expression (b7), the power of the first lens group becomes too strong, and it becomes difficult to maintain the off-axis performance in particular.

When the upper limit of the conditional expression (b8) is exceeded, the power of the second lens group becomes weak with respect to the angle of view, and it becomes difficult to shorten the total length. On the other hand, when it becomes less than the lower limit of the conditional expression (b8), the power of the second lens group becomes too strong, and it becomes difficult to maintain the performance both on-axis and off-axis.

As described above, according to another embodiment of the second invention, the optical overall length including the front lens diameter and the back focus is small, but high optical performance with little influence on environmental changes is achieved. It is possible to provide a wide-angle lens having a lens.

FIG. 13 shows the lens configuration of the lens system 700 in the fourth reference example together with the optical member P and the image plane IM. The lens system 700 is composed of a first lens group G1 having a negative refractive power, an aperture stop S, and a second lens group G2 having a positive refractive power in order from the object side.

The first lens group G1 is composed of a total of two lenses, one negative aspherical glass lens L1 with a concave surface facing the image side and a positive resin positive aspherical lens L2. Further, a positive glass spherical lens L3 having the strongest positive power in the group is arranged on the most object side of the second lens group G2, and the other lenses L4 to L8 are resin lenses. With this configuration, the power of the first lens group G1 and the second lens group G2 is strengthened while suppressing the aberration fluctuation at the time of environmental change, and the spherical aberration and the off-axis aberration are good in the lens system having a short total length and a small lens diameter. It is possible to correct to.

The second lens group G2 includes a biconvex positive glass spherical lens L3, a positive aspherical meniscus lens L4 with a concave surface facing the object side, a negative aspherical lens L5, and a positive aspherical lens L6. , A total of 6 lenses, a negative aspherical lens L7 and a negative aspherical lens L8. By using a glass glass material with a high Abbe number for the positive glass spherical lens L3 in the second lens group G2, aberration correction is appropriately performed for each angle of view ray, and axial chromatic aberration and magnification chromatic aberration are well corrected. It can be achieved with a good balance. Further, by using a plastic glass material having a low Abbe number for the fifth and sixth lenses from the object side in the second lens group G2, the chromatic aberration of magnification is particularly well corrected. Further, as described above, by configuring the lens having the strongest power in each lens group of the first lens group and the second lens group with glass, it is possible to suppress aberration fluctuations due to environmental changes, and while reducing the size, It improves the environmental reliability of the entire lens system.

Table 21 shows the lens data of the lens system 700. Table 22 is a table showing the aspherical surface data of the lens system 700.

Table 23 is a table of specification data showing the focal length f, F number Fno, half angle of view ω, and image height Y of the entire system when the lens system 700 is focused on the infinity subject.

FIG. 14 shows spherical aberration, astigmatism, and distortion in a state where the lens system 700 is focused on an infinity subject. In spherical aberration, the alternate long and short dash line indicates the value of the C line (656.27 nm), the solid line indicates the value of the d line (587.56 nm), and the broken line indicates the value of the g line (435.84 nm). In astigmatism, the solid line shows the value of the sagittal image plane of the d line, and the broken line shows the value of the meridional image plane of the d line. In distortion, the solid line indicates the value of the d line. From each aberration diagram, it is clear that the lens system 700 has various aberrations corrected well and has excellent imaging performance.

FIG. 15 shows the lens configuration of the lens system 800 in the fifth reference example together with the optical member P and the image plane IM. The lens system 800 is composed of a first lens group G1 having a negative refractive power, an aperture stop S, and a second lens group G2 having a positive refractive power in order from the object side.

The first lens group G1 is composed of a total of two lenses, one negative aspherical glass lens L1 with a concave surface facing the image side and a positive aspherical glass lens L2. Further, a positive glass spherical lens L3 having the strongest positive power in the group is arranged on the most object side of the second lens group G2, and the other lenses are resin lenses. With this configuration, it is possible to enhance the power of the first lens group G1 and the second lens group G2 to satisfactorily correct spherical aberration and off-axis aberration in a lens system having a short overall length and a small lens diameter.

The second lens group G2 includes a biconvex positive glass spherical lens L3, a positive aspherical lens L4, a negative aspherical lens L5, a positive aspherical lens L6, and a negative aspherical lens L7. It is composed of a total of 5 sheets. By using a glass glass material with a high Abbe number for the positive glass spherical lens L3 in the second lens group G2, aberration correction is appropriately performed for each angle of view ray, and axial chromatic aberration and magnification chromatic aberration are well corrected. It can be achieved with a good balance. Further, by using a plastic glass material having a low Abbe number for the fifth lens from the object side in the second lens group G2, the chromatic aberration of magnification is particularly well corrected. Further, as described above, by using glass as the lens having the strongest power in each of the first lens group and the second lens group, it is possible to suppress aberration fluctuations due to environmental changes, resulting in miniaturization and overall lens size. It achieves both improved environmental reliability in the system.

Table 24 shows the lens data of the lens system 800. Table 25 is a table showing the aspherical surface data of the lens system 800.

Table 26 is a table of specification data showing the focal length f, F number Fno, half angle of view ω, and image height Y of the entire system when the lens system 800 is focused on the infinity subject.

FIG. 16 shows spherical aberration, astigmatism, and distortion in a state where the lens system 800 is focused on an infinity subject. In spherical aberration, the alternate long and short dash line indicates the value of the C line (656.27 nm), the solid line indicates the value of the d line (587.56 nm), and the broken line indicates the value of the g line (435.84 nm). In astigmatism, the solid line shows the value of the sagittal image plane of the d line, and the broken line shows the value of the meridional image plane of the d line. In distortion, the solid line indicates the value of the d line. From each aberration diagram, it is clear that the lens system 800 has various aberrations corrected well and has excellent imaging performance.

FIG. 17 shows the lens configuration of the lens system 900 in the sixth reference example together with the optical member P and the image plane IM. The lens system 900 is composed of a first lens group G1 having a negative refractive power, an aperture stop S, and a second lens group G2 having a positive refractive power in order from the object side.

The first lens group G1 is a total of three lenses, a negative aspherical glass lens L1 with a concave surface facing the image side, a negative aspherical glass lens L2 with a concave surface facing the object side, and a positive spherical glass lens L3. It is composed. A positive glass aspherical lens L4 having the strongest positive power in the group is arranged on the most object side of the second lens group G2, and the other lenses are resin lenses. With this configuration, it is possible to enhance the power of the first lens group G1 and the second lens group G2 to satisfactorily correct spherical aberration and off-axis aberration in a lens system having a short overall length and a small lens diameter.

The second lens group G2 includes a biconvex positive glass aspherical lens L4, a negative aspherical lens L5, a negative aspherical lens L6, a positive aspherical lens L7, and a negative aspherical lens L8. It is composed of a total of 5 sheets. By using a glass glass material with a high Abbe number for the positive glass aspherical lens L4 in the second lens group G2, aberration correction is appropriately performed for each angle of view ray, and axial chromatic aberration and magnification chromatic aberration are corrected. It can be achieved with a good balance. Further, by using a plastic glass material having a low Abbe number for the fifth lens from the object side in the second lens group G2, axial chromatic aberration is particularly well corrected. Further, as described above, by using glass as the lens having the strongest power among the lens groups of the first lens group G1 and the second lens group G2, it is possible to suppress aberration fluctuations due to environmental changes, resulting in miniaturization. It achieves both improved environmental reliability in the entire lens system.

Table 27 shows the lens data of the lens system 900. Table 28 is a table showing the aspherical surface data of the lens system 900.

Table 29 is a table of specification data showing the focal length f, F number Fno, half angle of view ω, and image height Y of the entire system when the lens system 900 is focused on the infinity subject.

FIG. 18 shows spherical aberration, astigmatism, and distortion in a state where the lens system 900 is focused on an infinity subject. In spherical aberration, the alternate long and short dash line indicates the value of the C line (656.27 nm), the solid line indicates the value of the d line (587.56 nm), and the broken line indicates the value of the g line (435.84 nm). In astigmatism, the solid line shows the value of the sagittal image plane of the d line, and the broken line shows the value of the meridional image plane of the d line. In distortion, the solid line indicates the value of the d line. From each aberration diagram, it is clear that the lens system 900 has various aberrations corrected well and has excellent imaging performance.

Table 30 shows the numerical values calculated by the mathematical formulas (b1) to (b10) in the lens system of the 4th reference example to the 6th reference example. Since the sixth reference example is not subject to the evaluation of the conditional expressions (b4) to (b10), the description of the numerical values of the conditional expressions (b4) to (b10) of the sixth reference example is omitted.

The configuration provided in the above-mentioned lens system can be any combination, and can be appropriately selectively adopted according to the required specifications. For example, the lens system according to the above reference example may satisfy any one of the conditional expressions (b1) to (b10), or may satisfy any combination of these conditional expressions. ..

As described above, according to the lens configuration provided in the lens system according to the 4th reference example to the 6th reference example, the total optical length including the front lens diameter and the back focus is small, but it has an influence on environmental changes. It is possible to provide an ultra-wide-angle lens having a small amount of high optical performance.

As a lens system for an image pickup device, a wide-angle lens, a short front lens diameter and a short lens length, a small size of the entire system, and high optical performance are required. The following documents are disclosed as an image pickup lens.

[Patent Document 7] Japanese Patent Application Laid-Open No. 2016-206223 [Patent Document 8] Japanese Patent Application Laid-Open No. 6335332

Patent Document 7 describes an imaging lens composed of a glass lens and a resin lens, but the HFOV is 60 ° or less and the angle of view is not wide, and the group before the aperture (first lens group) is all a resin lens. It is difficult to sufficiently increase the power of the first lens group while maintaining the optical performance, and the lens is not sufficiently miniaturized with respect to the angle of view. Further, in order to further widen the angle of view, it is necessary to strengthen the refractive power of the first lens group, but when the first lens group is all made of resin, the refractive power of the first lens group is maintained while maintaining the performance and size. It is difficult to strengthen. Therefore, the lens group tends to be large. In addition, there is a limit to strengthening the power of the lens group composed of only resin in terms of suppressing aberration fluctuations when the environment changes. Further, the exit pupil distance with respect to the image height is long, and it cannot be said that it is a small image pickup lens. Patent Document 8 describes an imaging lens composed of a glass lens and a resin lens, but the rear group (second lens group) behind the aperture is entirely composed of a resin lens, while maintaining optical performance. It becomes difficult to increase the power of the first lens group and the second lens group. Further, in terms of suppressing aberration fluctuations when the environment changes, there is a limit to strengthening the power of the lens group composed of only resin. On the other hand, according to the lens system according to the embodiment described in relation to the above reference example, the problem can be alleviated.

Although the embodiments, examples and reference examples have been described above, the present invention is not limited to the above-described embodiments, examples and reference examples, and various modifications are possible. For example, the radius of curvature, the interplanar spacing, the refractive index, and the Abbe number of each lens are not limited to the values shown in each of the above embodiments, and may take other values.

The lens system according to the above embodiment described in relation to the first to third embodiments and the first to sixth reference examples is a lens system for an image pickup device such as a digital camera or a video camera. Applicable. The lens system according to the present embodiment can be applied to a lens system that does not have a zoom mechanism. The lens system according to the present embodiment can be applied to a lens system such as an aerial photography camera and a surveillance camera. The lens system according to the present embodiment can be applied to an image pickup lens included in a non-interchangeable lens image pickup device. The lens system according to this embodiment can be applied to an interchangeable lens of an interchangeable lens camera such as a single-lens reflex camera. The lens system according to the present embodiment can be applied to an image pickup device of a mobile phone or a mobile information terminal having an image pickup function.

FIG. 19 shows an example of an external perspective view of an image pickup apparatus 2000 including the lens system according to the above embodiment. FIG. 20 is a diagram showing a functional block of the image pickup apparatus 2000.

The image pickup apparatus 2000 includes an image pickup unit 2100 and a lens unit 2200. The image pickup unit 2100 includes an image sensor 2120, a control unit 2110, a memory 2130, an instruction unit 2162, a display unit 2160, and a communication unit 2170.

The image sensor 2120 may be configured by CCD or CMOS. The image sensor 2120 receives light via the image pickup lens system 2210 included in the lens unit 2200. The image sensor 2120 outputs the image data of the optical image imaged via the image pickup lens system 2210 to the control unit 2110. The image pickup lens system 2210 includes the lens system according to the above-described embodiment.

The control unit 2110 may be configured by a microprocessor such as a CPU or MPU, a microcontroller such as an MCU, or the like. The memory 2130 may be a computer-readable recording medium and may include at least one of flash memories such as SRAM, DRAM, EPROM, EEPROM, and USB memory. The control unit 2110 corresponds to the circuit. The memory 2130 stores programs and the like necessary for the control unit 2110 to control the image sensor 2120 and the like. The memory 2130 may be provided inside the housing of the image pickup apparatus 2000. The memory 2130 may be provided so as to be removable from the housing of the image pickup apparatus 2000.

The instruction unit 2162 is a user interface that receives instructions from the user to the image pickup apparatus 2000. The display unit 2160 displays an image captured by the image sensor 2120 and processed by the control unit 2110, various setting information of the image pickup device 2000, and the like. The display unit 2160 may be composed of a touch panel.

The control unit 2110 controls the image sensor 2120. The control unit 2110 outputs a control command to the image sensor 2120 based on the information indicating the user's instruction acquired through the instruction unit 2162 or the like, thereby executing the control including the control of the image pickup operation to the image sensor 2120. The control unit 2110 acquires an image captured by the image sensor 2120. The control unit 2110 performs image processing on the image acquired from the image sensor 2120 and stores it in the memory 2130.

The communication unit 2170 is responsible for communication with the outside. The communication unit 2170 transmits the information generated by the control unit 2110 to the outside through the communication network. The communication unit 2170 provides the control unit 2110 with information received from the outside through the communication network.

Next, an embodiment of a mobile body system including a mobile body including the lens system according to the above embodiment will be described.

FIG. 21 schematically shows an example of a mobile system 10 including an unmanned aerial vehicle (UAV) 40 and a controller 50. The UAV 40 includes a UAV main body 1101, a gimbal 1110, a plurality of image pickup devices 1230, and an image pickup device 1220. The image pickup device 1220 includes a lens device 1160 and an image pickup unit 1140. The lens device 1160 includes the lens system described above. The UAV 40 is an example of a moving body provided with an image pickup apparatus having the above-mentioned lens system. The moving body is a concept including UAV, other aircraft moving in the air, vehicles moving on the ground, ships moving on the water, and the like.

The UAV main body 1101 includes a plurality of rotor blades. The UAV main body 1101 flies the UAV 40 by controlling the rotation of a plurality of rotor blades. The UAV main body 1101 flies the UAV 40 using, for example, four rotor blades. The number of rotor blades is not limited to four. The UAV40 may be a fixed-wing aircraft without rotary wings.

The image pickup apparatus 1230 is an image pickup camera that captures an image of a subject included in a desired image pickup range. The plurality of image pickup devices 1230 are cameras for sensing that image the surroundings of the UAV 40 in order to control the flight of the UAV 40. The image pickup apparatus 1230 may be fixed to the UAV main body 1101. The image pickup lens system included in the image pickup apparatus 1230 may include the above-mentioned lens system.

Two image pickup devices 1230 may be provided in front of the nose of the UAV 40. Yet two other imaging devices 1230 may be provided on the bottom surface of the UAV 40. The two image pickup devices 1230 on the front side may be paired and function as a so-called stereo camera. The two image pickup devices 1230 on the bottom side may also be paired and function as a stereo camera. Three-dimensional spatial data around the UAV 40 may be generated based on the images captured by the plurality of image pickup devices 1230. The distance to the subject imaged by the plurality of image pickup devices 1230 can be specified by the stereo cameras by the plurality of image pickup devices 1230.

The number of image pickup devices 1230 included in the UAV 40 is not limited to four. The UAV 40 may include at least one image pickup device 1230. The UAV 40 may be equipped with at least one image pickup device 1230 on each of the nose, tail, side surface, bottom surface, and ceiling surface of the UAV 40. In the description of the UAV 40, the plurality of image pickup devices 1230 may be simply collectively referred to as the image pickup device 1230.

The controller 50 includes a display unit 54 and an operation unit 52. The operation unit 52 receives an input operation for controlling the posture of the UAV 40 from the user. The controller 50 transmits a signal for controlling the UAV 40 based on the user's operation received by the operation unit 52.

The controller 50 receives an image captured by at least one of the image pickup device 1230 and the image pickup device 1220. The display unit 54 displays the image received by the controller 50. The display unit 54 may be a touch-type panel. The controller 50 may accept an input operation from the user through the display unit 54. The display unit 54 may accept a user operation or the like in which the user specifies the position of the subject to be imaged by the image pickup apparatus 1220.

The image pickup unit 1140 generates and records image data of an optical image imaged by the lens device 1160. The lens device 1160 may be provided integrally with the image pickup unit 1140. The lens device 1160 may be a so-called interchangeable lens. The lens device 1160 may be detachably provided with respect to the image pickup unit 1140. The lens device 1160 may include the lens system described above.

The gimbal 1110 has a support mechanism that movably supports the image pickup apparatus 1220. The image pickup apparatus 1220 is attached to the UAV main body 1101 via the gimbal 1110. The gimbal 1110 rotatably supports the image pickup apparatus 1220 about the pitch axis. The gimbal 1110 rotatably supports the image pickup device 1220 about a roll axis. The gimbal 1110 rotatably supports the image pickup device 1220 about the yaw axis. The gimbal 1110 may rotatably support the image pickup device 1220 about at least one axis, a pitch axis, a roll axis, and a yaw axis. The gimbal 1110 may rotatably support the image pickup device 1220 around each of the pitch axis, roll axis, and yaw axis. The gimbal 1110 may hold the imaging unit 1140. The gimbal 1110 may hold the lens device 1160. The gimbal 1110 may change the imaging direction of the imaging device 1220 by rotating the imaging unit 1140 and the lens device 1160 around at least one of the yaw axis, the pitch axis, and the roll axis.

Next, a stabilizer as an example of the system including the lens system according to the above embodiment will be described.

FIG. 22 is an external perspective view showing an example of the stabilizer 3000. The stabilizer 3000 is another example of a moving body. For example, the camera unit 3013 included in the stabilizer 3000 may include an image pickup device having the same configuration as the image pickup device 1220. The camera unit 3013 may include a lens device having the same configuration as the lens device 1160.

The stabilizer 3000 includes a camera unit 3013, a gimbal 3020, and a handle portion 3003. The gimbal 3020 rotatably supports the camera unit 3013. The gimbal 3020 has a pan shaft 3009, a roll shaft 3010, and a tilt shaft 3011. The gimbal 3020 rotatably supports the camera unit 3013 around the pan shaft 3009, the roll shaft 3010, and the tilt shaft 3011. The gimbal 3020 is an example of a support mechanism.

The camera unit 3013 is an example of an image pickup device. The camera unit 3013 has a slot 3014 for inserting a memory. The gimbal 3020 is fixed to the handle portion 3003 via the holder 3007.

The handle portion 3003 has various buttons for operating the gimbal 3020 and the camera unit 3013. The handle portion 3003 includes a shutter button 3004, a recording button 3005, and an operation button 3006. When the shutter button 3004 is pressed, the camera unit 3013 can record a still image. By pressing the record button 3005, the camera unit 3013 can record a moving image.

The device holder 3001 is fixed to the handle portion 3003. The device holder 3001 holds a mobile device 3002 such as a smartphone. The mobile device 3002 is communicably connected to the stabilizer 3000 via a wireless network such as WiFi. As a result, the image captured by the camera unit 3013 can be displayed on the screen of the mobile device 3002.

Also in the stabilizer 3000, the camera unit 3013 may include the lens system according to the above embodiment.

In the above, the UAV 40 and the stabilizer 3000 have been taken up and described as examples of the moving body. An image pickup device having the same configuration as the image pickup device 1220 may be attached to a moving body other than the UAV 40 and the stabilizer 3000.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that the form with such changes or improvements may be included in the technical scope of the present invention.

The order of execution of each process such as operation, procedure, step, and step in the apparatus, system, program, and method shown in the claims, the specification, and the drawing is particularly "before" and "prior to". It should be noted that it can be realized in any order unless the output of the previous process is used in the subsequent process. Even if the scope of claims, the specification, and the operation flow in the drawings are explained using "first", "next", etc. for convenience, it means that it is essential to carry out in this order. It's not a thing.

100, 200, 300, 400, 500, 600, 700, 800, 900 Lens system 2000 image pickup device, 2100 image pickup unit, 2110 control unit, 2120 image sensor, 2130 memory, 2160 display unit, 2162 indicator unit, 2170 communication unit, 2200 lens unit, 2210 imaging lens system, 10 mobile system, 40 UAV, 50 controller, 52 operation unit, 54 display unit, 1101 UAV main unit, 1110 gimbal, 1140 imaging unit, 1160 lens device, 1220, 1230 imaging device, 3000 Stabilizer, 3001 device holder, 3002 mobile device, 3003 handle, 3004 shutter button 3005 record button, 3006 operation button, 3007 holder, 3009 pan axis, 3010 roll axis, 3011 tilt axis, 3013 camera unit, 3014 slot, 3020 gimbal

Claims (13)

A first lens group, an aperture diaphragm, and a second lens group are provided in order from the object side.
The first lens group includes a first lens having the most negative refractive power on the object side, and at least one lens having a positive refractive power on the image plane side of the first lens.
The second lens group includes a lens having a positive refractive power, a lens having a negative refractive power, and a lens having a positive refractive power in order from the object side, and a lens having aspherical surfaces on both sides on the most image plane side. Equipped with
A conditional expression, where f1 is the focal length of the lens on the most object side, f is the focal length of the entire system, and fL is the focal length of the lens on the image plane side.
1.00 <| f1 | / f <4.00
-0.2 <f / fL <0.2
A lens system that satisfies. The lens on the most image plane side has a central portion that is convex toward the object side on both the surface on the object side and the surface on the image plane side, and has an inflection point once up to the peripheral portion, and the peripheral portion is on the object side. The lens system according to claim 1, which has a concave shape. Conditional expression 1.5 / f_1G / f <10, where the focal length of the first lens group is f_1G.
The lens system according to claim 1 or 2. Conditional expression 1.5 / f_2G / f <5.0, where the focal length of the second lens group is f_2G.
The lens system according to claim 1 or 2. Of the lens having a positive refractive power, the lens having a negative refractive power, and the lens having a positive refractive power, which the second lens group has in order from the object side, the lens has the positive refractive power on the object side. The conditional expression 1.3 <f_p1 / f <2.6, where the focal distance of the lens is f_p1 and the focal distance of the lens having a positive refractive power on the image plane side is f_p2.
1.1 <f_p2 / f <5.0
The lens system according to claim 1 or 2. Conditional expression 2.7 <TTL / Y < 3.6
The lens system according to claim 1 or 2. Conditional expression 1.2 <L_sto / Y <2.0, where the distance on the optical axis from the aperture stop to the image plane is L_sho and the maximum image height is Y.
The lens system according to claim 1 or 2. The conditional expression 23.0 <v1 <42.0, where v1 is the Abbe number of the lens having a positive refractive power of the first lens group.
The lens system according to claim 1 or 2. The conditional equation -1.6 <fn / f <-0.8, where fn is the combined focal length of the lens on the object side of the lens having a positive refractive power of the first lens group.
The lens system according to claim 1 or 2. The first lens group includes three or more consecutively adjacent glass lens groups in order from the object side.
The lens system according to claim 1 or 2, wherein the second lens group includes four or more consecutively adjacent plastic lenses. The lens system according to claim 1 or 2,
An image pickup device equipped with an image sensor. A moving body that moves with the lens system according to claim 1 or 2. The mobile body according to claim 12, wherein the mobile body is an unmanned aerial vehicle.

Images