JP2022049359A - Lens system, image capturing device, and mobile body - Google Patents

Abstract

To provide a lens system which features a wide view angle, compactness, and high resolution.SOLUTION: A lens system comprises a first lens L1 with negative refractive power having an object-side surface that is concave near an optical axis and an image-side surface that is convex, a second lens L2 with positive refractive power, a third lens L3 with positive refractive power, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8 with negative refractive power having an image-side surface that is concave near the optical axis, and satisfies the following conditional expression: 1.3<f12/f<4.5, where f12 represents a composite focal length of the first lens L1 and the second lens L2 and f represents a focal length of the entire system.SELECTED DRAWING: Figure 1

Description

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

Patent Document 1 describes a lens system having a six-element configuration and having a half angle of view exceeding 45 degrees. Patent Document 2 describes a lens system having eight elements.
[Prior Art Document]
[Patent Document]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2018-526661 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-116594

The lens system according to one aspect of the present invention has a first lens having a negative refractive force in which the shape near the optical axis has a concave surface on the object side and a convex surface on the image side in order from the object side, and a positive refractive force. The second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, which have a positive refractive force, have a concave surface facing the image side near the optical axis and exert a negative refractive force. It may be provided with an eighth lens to have. Conditional expression 1.3 <f12 / f <4.5, where the combined focal length of the first lens and the second lens is f12 and the focal length of the entire system is f.
May be satisfied.

The conditional expression 65 <v4 + v5 + v6 <125, where v4 is the Abbe number on the d-line of the fourth lens, v5 is the Abbe number on the d-line of the fifth lens, and v6 is the Abbe number on the d-line of the sixth lens.
May be satisfied.

Conditional expression D23 / TT <0.15, where the air gap between the second lens and the third lens is D23 and the total optical length is TT.
May be satisfied.

Conditional expression 1 <TT / Y <2.2, where the maximum image height is Y and the total optical length is TT.
May be satisfied.

Assuming that the focal length of the second lens is f2 and the focal length of the third lens is f3, the conditional expression 0.6 <f2 / f3 <2.5
May be satisfied.

Assuming that the focal length of the 4th lens is f4, the focal length of the 5th lens is f5, and the focal length of the 6th lens is f6, the conditional expression 1.5 << f4 / f |
1.5 << | f5 / f |
1.5 << | f6 / f |
May be satisfied.

Let v1 be the Abbe number on the d-line of the first lens.
v1> 40
May be satisfied.

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 lens system having a wide angle of view. According to the above lens system, a compact lens system can be provided. According to the above lens system, it is possible to provide a lens system having a high resolving power.

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. The spherical aberration, astigmatism, and distortion of the lens system 100 in a state of being in focus on an infinity subject are shown. 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. The spherical aberration, astigmatism, and distortion of the lens system 200 in a state of being in focus on an infinity subject are shown. 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, and distortion of the lens system 300 in the state of being in focus on the infinity subject are shown. The lens configuration of the lens system 400 in Example 4 is shown together with the optical member P and the image plane IM. The spherical aberration, astigmatism, and distortion of the lens system 400 in the state of being in focus on the infinity subject are shown. The lens configuration of the lens system 500 in Example 5 is shown together with the optical member P and the image plane IM. The spherical aberration, astigmatism, and distortion of the lens system 500 in the state of being in focus on the infinity subject are shown. The lens configuration of the lens system 600 in Example 6 is shown together with the optical member P and the image plane IM. The spherical aberration, astigmatism, and distortion of the lens system 600 in the state of being in focus on the infinity subject are shown. An example of an external perspective view of an image pickup apparatus 2000 including a lens system according to the present 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.

Examples of the lens system are disclosed in connection with FIGS. 1 to 12. As disclosed in each embodiment, in the lens system of one embodiment, the first lens system has a negative refractive force in which the shape near the optical axis has a concave surface on the object side and a convex surface on the image side in order from the object side. An image of a lens, a second lens having a positive refractive force, a third lens having a positive refractive force, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an image near the optical axis. It is equipped with an eighth lens having a negative refraction force with a concave surface facing to the side. Conditional expression 1.3 <f12 / f <4.5 ... (1), where the combined focal length of the first lens and the second lens is f12 and the focal length of the entire system is f.
To be satisfied.

The conditional expression (1) defines the relationship between the combined focal length of the first lens and the second lens and the focal length of the entire system. When the upper limit of the conditional expression (1) or more is exceeded, the combined refractive power of the first lens and the second lens becomes weak, and it becomes difficult to shorten the total length of the lens system. On the other hand, when it becomes less than the lower limit of the conditional expression (1), the combined refractive power of the first lens and the second lens becomes too strong, so that aberration correction becomes difficult and the performance deterioration of the lens system due to the eccentricity error becomes large. ..

Further, the above-mentioned effect becomes more remarkable by satisfying the following conditional expression (1-1).
1.6 <f12 / f <4.0 ... (1-1)

The conditional expression 65 <v4 + v5 + v6 <125 ... (2), where the Abbe number on the d-line of the fourth lens is v4, the Abbe number on the d-line of the fifth lens is v5, and the Abbe number on the d-line of the sixth lens is v6.
To be satisfied.

The conditional expression (2) defines the sum of the Abbe numbers on the d-line of each of the fourth lens, the fifth lens, and the sixth lens. By satisfying the conditional expression (2), chromatic aberration can be satisfactorily corrected.

Conditional expression D23 / TT <0.15 ... (3), where the air gap between the second lens and the third lens is D23 and the total optical length is TT.
To be satisfied.

The conditional expression (3) defines the relationship between the air gap between the second lens and the third lens and the optical total length. When the upper limit of the conditional expression (3) is exceeded, the air gap between the second lens and the third lens becomes large, and it becomes difficult to reduce the size of the lens system. Further, if the height of the off-axis light rays passing through the lenses before and after the aperture is increased in order to widen the angle of view, it becomes difficult to correct the off-axis aberrations.

Conditional expression 1 <TT / Y <2.2 ... (4), where the maximum image height is Y and the total optical length is TT.
To be satisfied.

The conditional expression (4) defines the relationship between the maximum image height and the total optical length. When the upper limit of the conditional expression (4) or more is exceeded, the total optical length of the lens system becomes long, and it becomes difficult to reduce the size of the lens system. On the other hand, when it is equal to or less than the lower limit of the conditional expression (4), the total optical length becomes short, but the refractive power of each lens becomes strong, it becomes difficult to correct the aberration, and the performance deterioration of the lens system due to the eccentricity error becomes large.

Further, the above-mentioned effect becomes more remarkable by satisfying the following conditional expression (4-1).
1.3 <TT / Y <1.9 ... (4-1)

Assuming that the focal length of the second lens is f2 and the focal length of the third lens is f3, the conditional expression 0.6 <f2 / f3 <2.5 ... (5)
To be satisfied.

The conditional expression (5) defines the relationship between the focal length of the second lens and the focal length of the third lens. By satisfying the conditional expression (5), the refractive power required for wide-angle lensing can be shared between the second lens and the third lens, and axial aberration correction can be performed satisfactorily. If the conditional expression (5) is not satisfied, the refractive power required for wide-angle lensing is biased to either lens, which makes it difficult to correct aberrations in a lens with a strong refractive power and deteriorates the performance of the lens system due to eccentricity error. growing.

Further, the above-mentioned effect becomes more remarkable by satisfying the following conditional expression (5-1).
0.9 <f2 / f3 <2.1 ... (5-1)

Assuming that the focal length of the 4th lens is f4, the focal length of the 5th lens is f5, and the focal length of the 6th lens is f6, the conditional equation 1.5 << | f4 / f | ... (6a)
1.5 << | f5 / f | ... (6b)
1.5 << | f6 / f | ... (6c)
To be satisfied.

The conditional expressions (6a) to (6c) define the relationship between the focal lengths of the 4th to 6th lenses and the focal lengths of the entire system. When it is equal to or less than the lower limit of each of the conditional expressions (6a) to (6c), the refractive power of each lens becomes too strong, it becomes difficult to correct the aberration, and the performance deterioration of the lens system due to the eccentricity error becomes large.

Let v1 be the Abbe number on the d-line of the first lens.
v1> 40 ... (7)
To be satisfied.

The conditional expression (7) defines the Abbe number of the first lens, and when the number is equal to or less than the lower limit of the conditional expression (7), it becomes difficult to correct the chromatic aberration of the off-axis light.

According to the above lens system, it is possible to provide a lens system having a wide angle of view. Further, it is possible to provide a small lens system. Further, it is possible to provide a lens system having a high resolving power.

In addition, when the terms "consisting of", "consisting of", and "consisting of" are used in the present specification and the like, they have substantially no refractive power in addition to the listed components. It may include optical elements other than lenses that have substantially refractive power, such as lenses, diaphragms, filters and cover glasses, 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.

Next, an example in which a specific numerical value is applied to a specific embodiment of the lens system will be described. First, the meanings of symbols and the like used in the description of each embodiment of the lens system will be described.

As lens data, a table showing 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 addition, a table of specification data of the lens system of each embodiment 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 when focusing on an infinity subject. "BF" indicates back focus.

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. As the lens system of the present embodiment, 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.

"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. In the description of each embodiment, 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 embodiments are the same lens.

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 includes a first lens L1, a second lens L2, an aperture aperture S, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and a seventh lens in order from the object side. It is composed of eight lenses of eight lenses L8. The first lens L1 has a negative refractive power. The second lens L2 has a positive refractive power. The third lens L3 has a positive refractive power. The fourth lens L4 has a negative refractive power. The fifth lens L5 has a negative refractive power. The sixth lens L6 has a positive refractive power. The seventh lens L7 has a positive refractive power. The eighth lens L8 has a negative refractive power.

The shape of the first lens L1 near the optical axis is a meniscus shape with a concave surface on the object side and a convex surface on the image side. The second lens L2 has a shape in which the shape near the optical axis faces a convex surface toward the object side. The third lens L3 has a shape in the vicinity of the optical axis facing a convex surface toward the image side. The fourth lens L4 has a shape in which the shape near the optical axis faces the concave surface toward the image side. The fifth lens L5 has a shape in which the shape near the optical axis faces the concave surface toward the object side. The sixth lens L6 has a shape in the vicinity of the optical axis with a concave surface facing the object side and a convex surface facing the image side. The seventh lens L7 has a shape in the vicinity of the optical axis with a convex surface facing the object side. The eighth lens L8 has a shape in the vicinity of the optical axis with a convex surface facing the object side and a concave surface facing the image side. It is desirable that the lens surface on the image plane side of the eighth lens L8 has an aspherical shape having an inflection point in which the uneven shape changes in the middle from the central portion to the peripheral portion, and the shape in the peripheral portion is convex. By doing so, the angle of incidence of the light emitted from the eighth lens L8 on the image pickup surface is suppressed.

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 shows the focal length f, F-number Fno, half angle of view ω, image height Y, total optical length TTL when focusing on the infinity subject, and the back when focusing on the infinity subject of the lens system 100. It is a table of specification data which shows a focus BF.

FIG. 2 shows spherical aberration, astigmatism, and distortion 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 broken line shows the value of the meridional image plane of the d line. In the distortion aberration, the value of the d line is shown. 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.

In the lens system 200, the first lens L1, the second lens L2, the aperture aperture S, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the seventh lens are arranged in this order from the object side. It is composed of eight lenses of eight lenses L8. The first lens L1 has a negative refractive power. The second lens L2 has a positive refractive power. The third lens L3 has a positive refractive power. The fourth lens L4 has a negative refractive power. The fifth lens L5 has a positive refractive power. The sixth lens L6 has a negative refractive power. The seventh lens L7 has a positive refractive power. The eighth lens L8 has a negative refractive power.

The shape of the first lens L1 near the optical axis is a meniscus shape with a concave surface on the object side and a convex surface on the image side. The second lens L2 has a shape in which the shape near the optical axis faces a convex surface toward the object side. The third lens L3 has a shape in the vicinity of the optical axis facing a convex surface toward the image side. The fourth lens L4 has a shape in which the shape near the optical axis faces the concave surface toward the image side. The fifth lens L5 has a shape in which the shape near the optical axis faces the concave surface toward the object side. The sixth lens L6 has a shape in the vicinity of the optical axis with a concave surface facing the object side and a convex surface facing the image side. The seventh lens L7 has a shape in the vicinity of the optical axis with a convex surface facing the object side. The eighth lens L8 has a shape in the vicinity of the optical axis with a convex surface facing the object side and a concave surface facing the image side. It is desirable that the lens surface on the image plane side of the eighth lens L8 has an aspherical shape having an inflection point in which the uneven shape changes in the middle from the central portion to the peripheral portion, and the shape in the peripheral portion is convex. By doing so, the angle of incidence of the light emitted from the eighth lens L8 on the image pickup surface is suppressed.

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 shows the focal length f, F-number Fno, half angle of view ω, image height Y, total optical length TTL when focusing on the infinity subject, and the back when focusing on the infinity subject of the lens system 200. It is a table of the specification data which shows the focus BF.

FIG. 4 shows spherical aberration, astigmatism, and distortion 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 broken line shows the value of the meridional image plane of the d line. In the distortion aberration, the value of the d line is shown. 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.

In the lens system 300, the first lens L1, the second lens L2, the aperture aperture S, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the seventh lens are arranged in this order from the object side. It is composed of eight lenses of eight lenses L8. The first lens L1 has a negative refractive power. The second lens L2 has a positive refractive power. The third lens L3 has a positive refractive power. The fourth lens L4 has a negative refractive power. The fifth lens L5 has a negative refractive power. The sixth lens L6 has a positive refractive power. The seventh lens L7 has a positive refractive power. The eighth lens L8 has a negative refractive power.

The shape of the first lens L1 near the optical axis is a meniscus shape with a concave surface on the object side and a convex surface on the image side. The second lens L2 has a shape in which the shape near the optical axis faces a convex surface toward the object side. The third lens L3 has a shape in the vicinity of the optical axis facing a convex surface toward the image side. The fourth lens L4 has a shape in which the shape near the optical axis faces the concave surface toward the image side. The fifth lens L5 has a shape in which the shape near the optical axis faces the concave surface toward the object side. The sixth lens L6 has a shape in the vicinity of the optical axis with a concave surface facing the object side and a convex surface facing the image side. The seventh lens L7 has a shape in the vicinity of the optical axis with a convex surface facing the object side. The eighth lens L8 has a shape in the vicinity of the optical axis with a convex surface facing the object side and a concave surface facing the image side. It is desirable that the lens surface on the image plane side of the eighth lens L8 has an aspherical shape having an inflection point in which the uneven shape changes in the middle from the central portion to the peripheral portion, and the shape in the peripheral portion is convex. By doing so, the angle of incidence of the light emitted from the eighth lens L8 on the image pickup surface is suppressed.

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 shows the focal length f, F-number Fno, half angle of view ω, image height Y, total optical length TTL when focusing on the infinity subject, and the back when focusing on the infinity subject of the lens system 300. It is a table of the specification data which shows the focus BF.

FIG. 6 shows spherical aberration, astigmatism, and distortion 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 broken line shows the value of the meridional image plane of the d line. In the distortion aberration, the value of the d line is shown. From each aberration diagram, it is clear that the lens system 300 has various aberrations corrected well and has excellent imaging performance.

FIG. 7 shows the lens configuration of the lens system 400 in the fourth embodiment together with the optical member P and the image plane IM.

In the lens system 400, the first lens L1, the second lens L2, the aperture aperture S, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the seventh lens are arranged in this order from the object side. It is composed of eight lenses of eight lenses L8. The first lens L1 has a negative refractive power. The second lens L2 has a positive refractive power. The third lens L3 has a positive refractive power. The fourth lens L4 has a negative refractive power. The fifth lens L5 has a negative refractive power. The sixth lens L6 has a positive refractive power. The seventh lens L7 has a positive refractive power. The eighth lens L8 has a negative refractive power.

The shape of the first lens L1 near the optical axis is a meniscus shape with a concave surface on the object side and a convex surface on the image side. The second lens L2 has a shape in which the shape near the optical axis faces a convex surface toward the object side. The third lens L3 has a shape in the vicinity of the optical axis facing a convex surface toward the image side. The fourth lens L4 has a shape in which the shape near the optical axis faces the concave surface toward the image side. The fifth lens L5 has a shape in which the shape near the optical axis faces the concave surface toward the object side. The sixth lens L6 has a shape in the vicinity of the optical axis with a concave surface facing the object side and a convex surface facing the image side. The seventh lens L7 has a shape in the vicinity of the optical axis with a convex surface facing the object side. The eighth lens L8 has a shape in the vicinity of the optical axis with a convex surface facing the object side and a concave surface facing the image side. It is desirable that the lens surface on the image plane side of the eighth lens L8 has an aspherical shape having an inflection point in which the uneven shape changes in the middle from the central portion to the peripheral portion, and the shape in the peripheral portion is convex. By doing so, the angle of incidence of the light emitted from the eighth lens L8 on the image pickup surface is suppressed.

Table 10 shows the lens data of the lens system 400. Table 11 is a table showing the aspherical surface data of the lens system 400.

Table 12 shows the focal length f, F-number Fno, half angle of view ω, image height Y, total optical length TTL when focusing on the infinity subject, and the back when focusing on the infinity subject of the lens system 400. It is a table of specification data which shows a focus BF.

FIG. 8 shows spherical aberration, astigmatism, and distortion of the lens system 400 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 broken line shows the value of the meridional image plane of the d line. In the distortion aberration, the value of the d line is shown. 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 fifth embodiment together with the optical member P and the image plane IM.

The lens system 500 includes a first lens L1, a second lens L2, an aperture aperture S, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and a seventh lens in order from the object side. It is composed of eight lenses of eight lenses L8. The first lens L1 has a negative refractive power. The second lens L2 has a positive refractive power. The third lens L3 has a positive refractive power. The fourth lens L4 has a negative refractive power. The fifth lens L5 has a negative refractive power. The sixth lens L6 has a positive refractive power. The seventh lens L7 has a positive refractive power. The eighth lens L8 has a negative refractive power.

The shape of the first lens L1 near the optical axis is a meniscus shape with a concave surface on the object side and a convex surface on the image side. The second lens L2 has a shape in which the shape near the optical axis faces a convex surface toward the object side. The third lens L3 has a shape in the vicinity of the optical axis facing a convex surface toward the image side. The fourth lens L4 has a shape in which the shape near the optical axis faces the concave surface toward the image side. The fifth lens L5 has a shape in which the shape near the optical axis faces the concave surface toward the object side. The sixth lens L6 has a shape in the vicinity of the optical axis with a concave surface facing the object side and a convex surface facing the image side. The seventh lens L7 has a shape in the vicinity of the optical axis with a convex surface facing the object side. The eighth lens L8 has a shape in the vicinity of the optical axis with a convex surface facing the object side and a concave surface facing the image side. It is desirable that the lens surface on the image plane side of the eighth lens L8 has an aspherical shape having an inflection point in which the uneven shape changes in the middle from the central portion to the peripheral portion, and the shape in the peripheral portion is convex. By doing so, the angle of incidence of the light emitted from the eighth lens L8 on the image pickup surface is suppressed.

Table 13 shows the lens data of the lens system 500. Table 14 is a table showing the aspherical surface data of the lens system 500.

Table 15 shows the focal length f, F-number Fno, half angle of view ω, image height Y, total optical length TTL when focusing on the infinity subject, and the back when focusing on the infinity subject of the lens system 500. It is a table of specification data which shows a focus BF.

FIG. 10 shows spherical aberration, astigmatism, and distortion of the lens system 500 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 broken line shows the value of the meridional image plane of the d line. In the distortion aberration, the value of the d line is shown. 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 sixth embodiment together with the optical member P and the image plane IM.

The lens system 600 includes a first lens L1, a second lens L2, an aperture aperture S, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and a seventh lens in order from the object side. It is composed of eight lenses of eight lenses L8. The first lens L1 has a negative refractive power. The second lens L2 has a positive refractive power. The third lens L3 has a positive refractive power. The fourth lens L4 has a negative refractive power. The fifth lens L5 has a negative refractive power. The sixth lens L6 has a positive refractive power. The seventh lens L7 has a positive refractive power. The eighth lens L8 has a negative refractive power.

The shape of the first lens L1 near the optical axis is a meniscus shape with a concave surface on the object side and a convex surface on the image side. The second lens L2 has a shape in which the shape near the optical axis faces a convex surface toward the object side. The third lens L3 has a shape in the vicinity of the optical axis facing a convex surface toward the image side. The fourth lens L4 has a shape in which the shape near the optical axis faces the concave surface toward the image side. The fifth lens L5 has a shape in which the shape near the optical axis faces the concave surface toward the object side. The sixth lens L6 has a shape in the vicinity of the optical axis with a concave surface facing the object side and a convex surface facing the image side. The seventh lens L7 has a shape in the vicinity of the optical axis with a convex surface facing the object side. The eighth lens L8 has a shape in the vicinity of the optical axis with a convex surface facing the object side and a concave surface facing the image side. It is desirable that the lens surface on the image plane side of the eighth lens L8 has an aspherical shape having an inflection point in which the uneven shape changes in the middle from the central portion to the peripheral portion, and the shape in the peripheral portion is convex. By doing so, the angle of incidence of the light emitted from the eighth lens L8 on the image pickup surface is suppressed.

Table 16 shows the lens data of the lens system 600. Table 17 is a table showing the aspherical surface data of the lens system 600.

Table 18 shows the focal length f, F-number Fno, half angle of view ω, image height Y, total optical length TTL when focusing on the infinity subject, and the back when focusing on the infinity subject of the lens system 600. It is a table of specification data which shows a focus BF.

FIG. 12 shows spherical aberration, astigmatism, and distortion of the lens system 600 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 broken line shows the value of the meridional image plane of the d line. In the distortion aberration, the value of the d line is shown. From each aberration diagram, it is clear that the lens system 600 has various aberrations corrected well and has excellent imaging performance.

Table 19 shows the numerical values calculated by the mathematical formulas (1) to (7) in the lens system of Examples 1 to 6. Table 20 shows the numerical values of the variables of each of the mathematical formulas (1) to (7) in the lens system of Examples 1 to 6.

As described above, according to the lens configuration according to the lens system of the above embodiment, it is possible to provide a lens system having a high angle of view of 45 degrees, a small size, and a high resolution optimized for high pixel count. can.

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 satisfies the conditional expressions (1) to (7), (1-1), (4-1), and (5-1), but the conditional expression (1). Any one of (7), (1-1), (4-1), and (5-1) may be satisfied, and any combination of these conditional expressions may be satisfied. May be.

Although the present invention has been described above with reference to embodiments and examples, the present invention is not limited to the above embodiments and 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.

In recent years, in mobile terminals such as digital still cameras and mobile phones, there is a demand for further miniaturization of image pickup devices and lens systems in order to make the terminals themselves thinner and to secure a space for mounting multiple functions. In addition, at the same time as the miniaturization of image pickup devices such as CCDs and CMOSs, the number of pixels is increasing due to the miniaturization of the pixel pitch of the image pickup devices, and along with this, high performance is required for the lens system used in these image pickup devices. There is. In the image pickup lens described in Patent Document 1 described above, aberration correction is not sufficient for a high pixel image pickup device, and there is a problem in dealing with further increase in resolution. The image pickup lens described in Patent Document 2 has a narrow half-angle of view of about 35 degrees, and there is a problem in achieving both a wider angle of view and a smaller size. On the other hand, according to the lens system according to the above embodiment, the problem can be alleviated.

The lens system according to the present embodiment can be applied to a lens system for an image pickup device such as a digital camera or a video camera. 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. 13 shows an example of an external perspective view of the image pickup apparatus 2000 including the lens system according to the present embodiment. FIG. 14 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 formed through 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, EEPROM, 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 a lens system according to the present embodiment will be described.

FIG. 15 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 UAV 40 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-described embodiment and embodiment will be described.

FIG. 16 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 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 (10)

From the object side,
The first lens having a negative refractive power with the shape near the optical axis facing concave on the object side and convex on the image side,
A second lens with positive refractive power,
A third lens with positive refractive power,
With the 4th lens
With the 5th lens
With the 6th lens
With the 7th lens
It is equipped with an eighth lens having a negative refractive power with the concave surface facing the image side near the optical axis.
Conditional expression 1.3 <f12 / f <4.5, where the combined focal length of the first lens and the second lens is f12 and the focal length of the entire system is f.
A lens system that satisfies. The conditional expression 65 <v4 + v5 + v6 <125, where v4 is the Abbe number on the d-line of the fourth lens, v5 is the Abbe number on the d-line of the fifth lens, and v6 is the Abbe number on the d-line of the sixth lens.
The lens system according to claim 1. Conditional expression D23 / TT <0.15, where the air gap between the second lens and the third lens is D23 and the total optical length is TT.
The lens system according to claim 1 or 2. Conditional expression 1 <TT / Y <2.2, where the maximum image height is Y and the total optical length is TT.
The lens system according to claim 1 or 2. Assuming that the focal length of the second lens is f2 and the focal length of the third lens is f3, the conditional expression 0.6 <f2 / f3 <2.5.
The lens system according to claim 1 or 2. Assuming that the focal length of the fourth lens is f4, the focal length of the fifth lens is f5, and the focal length of the sixth lens is f6, the conditional expression 1.5 << f4 / f |
1.5 << | f5 / f |
1.5 << | f6 / f |
The lens system according to claim 1 or 2. Let v1 be the Abbe number on the d-line of the first lens.
v1> 40
The lens system according to claim 1 or 2. 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 9, wherein the mobile body is an unmanned aerial vehicle.

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