WO2021199923A1

WO2021199923A1 - Imaging lens and imaging device

Info

Publication number: WO2021199923A1
Application number: PCT/JP2021/008823
Authority: WO
Inventors: 拓陸山田; 松岡　大
Original assignee: ソニーグループ株式会社
Priority date: 2020-03-31
Filing date: 2021-03-05
Publication date: 2021-10-07
Also published as: JPWO2021199923A1

Abstract

This imaging lens comprises a first lens group, an aperture stop, and a second lens group that are disposed in order from an object side to an image side. The first lens group comprises, in order from the object side to the image side, a fist negative meniscus lens having an aspherical shape on both sides or one side with a convex surface facing the object side, a second negative meniscus lens with a convex surface facing the object side, and a single lens having negative refractive power or a unit having a negative-positive arrangement in order from the object side to the image side. The second lens group has a positive lens group that moves from the image side to the object side from focusing on an infinite-distance object to focusing on a short-distance object. The imaging lens satisfies conditional expression (1) and conditional expression (2). (1): 40.00 < νdL1 < 96.00, (2): -10.0 < fL1/f < -2.0 where νdL1 is the Abbe number at the d line of the first negative meniscus lens, fL1 is the focal length of the first meniscus lens, and f is the focal length of the entire system at the time of infinite-distance focusing.

Description

Imaging lens and imaging device

The present technology relates to an image pickup lens having a first lens group and a second lens group arranged in order from an object side to an image side, and a technical field of an image pickup apparatus in which such an image pickup lens is used.

In digital cameras and the like, there is a demand for a function capable of capturing a wide angle of view for landscape and indoor photography, and various imaging lenses having a large diameter have been proposed (for example, Patent Document 1 and Patent Document 2). reference).

However, optical systems with a wide angle of view and high resolution from the center to the periphery of the screen tend to have worse chromatic aberration of magnification, coma, and sagittal coma flare. Further, in recent years, with the increase in the number of pixels of digital cameras and the like, correction of various aberrations is strictly required for the optical system used.

JP-A-2009-193053 JP-A-2018-18041

The retrofocus type imaging device that has been proposed conventionally has a high refractive index because the lens that exists on the object side is the strongest negative lens, although it is relatively easy to widen the angle while ensuring the flange back. It is necessary to use a glass material. Further, in general, the higher the refractive index of a glass material, the smaller the Abbe number. Therefore, it is difficult to satisfactorily correct the chromatic aberration of magnification.

In Patent Document 1, various aberrations associated with an increase in aperture are corrected by forming the rear group in a Gauss type configuration symmetrical to the aperture stop. On the other hand, since it is necessary to have a strong negative refractive power on the object side, a lens having a negative refractive power on the object side has a small Abbe number. Therefore, the configuration is disadvantageous for correcting chromatic aberration of magnification.

Further, in Patent Document 2, by adopting a retrofocus type, a large diameter of a wide-angle lens is realized while ensuring a flange back, while a negative refractive power is applied to the object side with respect to an aperture diaphragm. The front group with the lens is arranged, and the positive refractive power is arranged on the image side. However, since the refractive power is asymmetrically arranged across the aperture diaphragm, distortion and chromatic aberration of magnification tend to occur easily.

Therefore, it is an object of the present technology imaging lens and imaging device to provide a wide-angle lens capable of increasing the aperture by correcting various aberrations.

First, the imaging lens according to the present technology consists of a first lens group, an aperture aperture, and a second lens group arranged in order from the object side to the image side, and the first lens group is from the object side to the image side. In order, a first negative meniscus lens having an aspherical shape on both sides or one side and having a convex surface facing the object side, a second negative meniscus lens having a convex surface facing the object side, and a single lens having a negative refractive power. Alternatively, it has a unit in which negative and positive are arranged in order from the object side to the image side, and the second lens group moves from the image side to the object side when focusing from an infinity object to a short-range object. It has a lens group and satisfies the following conditional equations (1) and (2).
(1) 40.00 <νdL1 <96.00
(2) -10.0 <fL1 / f <-2.0
However,
νdL1: Abbe number of the d line of the first negative meniscus lens fL1: Focal length of the first negative meniscus lens f: Focal length of the entire system at infinity focusing.

As a result, the negative refractive power is divided on the object side, and the Abbe number of the first negative meniscus lens and the negative refractive power of the first negative meniscus lens are optimized.

Secondly, it is desirable that the above-mentioned imaging lens according to the present technology satisfies the following conditional expression (5).
(5) 1.5 <fG2F / f <8.5
However,
fG2F: Focal length of the positive lens group in the second lens group f: Focal length of the entire system at infinity focusing.

This optimizes the focal length of the positive lens group that functions as the focus group.

Thirdly, it is desirable that the above-mentioned imaging lens according to the present technology satisfies the following conditional expression (6).
(6) 3 <| fG1 / fG2 |
However,
fG1: Focal length of the first lens group fG2: Focal length of the second lens group.

As a result, the ratio of the refractive powers of the first lens group and the second lens group is optimized.

Fourth, it is desirable that the above-mentioned imaging lens according to the present technology satisfies the following conditional expression (7).
(7) 0.30 <fL1 / fL2 <2.50
However,
fL1: Focal length of the first negative meniscus lens fL2: Focal length of the second negative meniscus lens.

As a result, the refractive powers of the first negative meniscus lens and the second negative meniscus lens are optimized respectively.

Fifth, it is desirable that the above-mentioned imaging lens according to the present technology satisfies the following conditional expression (8).
(8) -1.5 <fG2 / fLA <-0.2
However,
fG2: Focal length of the second lens group fLA: Focal length of the negative air lens having the strongest refractive power in the second lens group.

As a result, the refractive power of the negative air lens with respect to the second lens group is optimized.

Sixth, in the image pickup lens according to the present technology described above, the distance from the image plane side surface to the image plane of the most image side lens in the second lens group is set as the back focus, and the following conditional expression (9) is used. It is desirable to satisfy.
(9) 0.3 <BF / f <2.5
However,
BF: The back focus f: The focal length of the entire system when focusing at infinity.

This shortens the total length.

Seventh, it is desirable that the above-mentioned imaging lens according to the present technology satisfies the following conditional expression (10).
(10) 2.3 <SL1 <4.6
However,
SL1: Specific gravity of the first negative meniscus lens [g / square centimeter]
And.

As a result, the refractive index of the first negative meniscus lens is optimized.

Eighth, in the above-mentioned imaging lens according to the present technology, it is desirable that the first lens group is fixed when focusing from an infinity object to a short-distance object.

As a result, the first lens group, which has a large volume and a large weight with respect to the entire system, is not moved in the optical axis direction during focus drive.

Ninth, the imaging device according to the present technology includes an imaging lens and an imaging element that converts an optical image formed by the imaging lens into an electrical signal, and the imaging lenses are arranged in order from the object side to the image side. The first lens group is composed of a first lens group, an aperture aperture, and a second lens group. The first lens group has an aspherical shape on both sides or one side in order from the object side to the image side, and the convex surface is directed toward the object side. It has one negative meniscus lens, a second negative meniscus lens with a convex surface facing the object side, and a single lens having a negative refractive force or a unit in which negative and positive are arranged in order from the object side to the image side. The second lens group has a positive lens group that moves from the image side to the object side when focusing from an infinity object to a short-range object, and the following conditional equations (1) and (2) are used. I am satisfied.
(1) 40.00 <νdL1 <96.00
(2) -10.0 <fL1 / f <-2.0
However,
νdL1: Abbe number of the d line of the first negative meniscus lens fL1: Focal length of the first negative meniscus lens f: Focal length of the entire system at infinity focusing.

As a result, in the imaging lens, the negative refractive power is divided on the object side, and the Abbe number of the first negative meniscus lens and the negative refractive power of the first negative meniscus lens are optimized.

Tenth, another imaging lens according to the present technology includes a first lens group, an aperture aperture, and a second lens group arranged in order from the object side to the image side, and the first lens group is an image from the object side. A first negative meniscus lens having a convex surface facing the object side and a second negative meniscus lens having a convex surface facing the object side are provided in this order, and the first lens group has an aspherical surface on both sides or one side. The second lens has a positive lens having a shape and a lens unit composed of a lens having a negative refractive force closest to the object side of the positive lens to a lens closest to the object side of the positive lens. The group has a positive lens group that moves from the image side to the object side when focusing from an infinity object to a short-range object, and satisfies the following conditional equations (3) and (4). be.
(3) -35.00 <fLN / fLP <-1.05
(4) 1.00 <dLP / dS <1.55
However,
fLN: Focal length of the lens unit fLP: Focal length of the positive lens in the first lens group dLP: Distance from the object-side surface to the image surface of the positive lens in the first lens group dS: From the aperture aperture The distance to the image plane.

This makes it easier for the upper ray with an off-axis angle of view to pass through the center of the lens and the lower ray to pass around the lens, and the refractive power of a positive lens having an aspherical shape on both sides or one side and the positive ray having an aspherical shape on both sides or one side. The distance from the lens to the aperture aperture is optimized.

Eleventh, it is desirable that the following conditional expression (5) is satisfied in the above-mentioned imaging lens according to the present technology.
(5) 1.5 <fG2F / f <8.5
However,
fG2F: Focal length of the positive lens group in the second lens group f: Focal length of the entire system at infinity focusing.

Twelvely, it is desirable that the following conditional expression (6) is satisfied in the above-mentioned imaging lens according to the present technology.
(6) 3 <| fG1 / fG2 |
However,
fG1: Focal length of the first lens group fG2: Focal length of the second lens group.

Thirteenth, it is desirable that the following conditional expression (7) is satisfied in the above-mentioned imaging lens according to the present technology.
(7) 0.30 <fL1 / fL2 <2.50
However,
fL1: Focal length of the first negative meniscus lens fL2: Focal length of the second negative meniscus lens.

Fourteenth, it is desirable that the following conditional expression (8) is satisfied in the above-mentioned imaging lens according to the present technology.
(8) -1.5 <fG2 / fLA <-0.2
However,
fG2: Focal length of the second lens group fLA: Focal length of the negative air lens having the strongest refractive power in the second lens group.

Fifteenth, in the above-mentioned imaging lens according to the present technology, the distance from the image plane side surface of the most image side lens in the second lens group to the image plane is set as the back focus, and the following conditional expression ( It is desirable to satisfy 9).
(9) 0.3 <BF / f <2.5
However,
BF: The back focus f: The focal length of the entire system when focusing at infinity.

This shortens the total length.

Sixteenth, it is desirable that the following conditional expression (10) is satisfied in the above-mentioned imaging lens according to the present technology.
(10) 2.3 <SL1 <4.6
However,
SL1: Specific gravity of the first negative meniscus lens [g / square centimeter]
And.

Seventeenth, in the above-mentioned imaging lens according to the present technology, it is desirable that the first lens group is fixed at the time of focusing from an infinity object to a short-distance object.

Eighteenth, another imaging device according to the present technology includes an imaging lens and an imaging element that converts an optical image formed by the imaging lens into an electrical signal, and the imaging lens moves from the object side to the image side. It consists of a first lens group, an aperture aperture, and a second lens group arranged in order. The first lens group consists of a first negative meniscus lens having a convex surface facing the object side and an object in order from the object side to the image side. It has a second negative meniscus lens with a convex surface facing side, and the first lens group includes a positive lens having an aspherical shape on both sides or one side, and a negative refractive force closest to the object side of the positive lens. It has a lens unit composed of a lens having a lens to a lens closest to the object side of the positive lens, and the second lens group is an object from the image side when focusing from an infinity object to a short-range object. It has a positive lens group that moves to the side, and satisfies the following conditional equations (3) and (4).
(3) -35.00 <fLN / fLP <-1.05
(4) 1.00 <dLP / dS <1.55
However,
fLN: Focal length of the lens unit fLP: Focal length of the positive lens in the first lens group dLP: Distance from the object-side surface to the image surface of the positive lens in the first lens group dS: From the aperture aperture The distance to the image plane.

As a result, in the imaging lens, the upper ray of the off-axis angle of view passes through the center of the lens and the lower ray easily passes around the lens, and the refractive power of the positive lens having an aspherical shape on both sides or one side and the aspherical force on both sides or one side. The distance from the positive lens with the shape to the aperture aperture is optimized.

2 to 31 show an embodiment of the image pickup lens and the image pickup apparatus of the present technology, and this figure is a diagram showing a lens configuration of the first embodiment of the image pickup lens. It is a longitudinal aberration diagram in the numerical example which applied the specific numerical value to the 1st Embodiment, and is the figure which shows spherical aberration, astigmatism and distortion. It is a lateral aberration diagram in the numerical example which applied the specific numerical value to the 1st Embodiment. It is a figure which shows the lens structure of the 2nd Embodiment of an image pickup lens. It is a longitudinal aberration diagram in the numerical example which applied the specific numerical value to the 2nd Embodiment, and is the figure which shows spherical aberration, astigmatism and distortion. It is a lateral aberration diagram in the numerical example which applied the specific numerical value to the 2nd Embodiment. It is a figure which shows the lens structure of the 3rd Embodiment of an image pickup lens. It is a longitudinal aberration diagram in the numerical example which applied the specific numerical value to the 3rd Embodiment, and is the figure which shows spherical aberration, astigmatism and distortion. It is a lateral aberration diagram in the numerical example which applied the specific numerical value to the 3rd Embodiment. It is a figure which shows the lens structure of the 4th Embodiment of an image pickup lens. It is a longitudinal aberration diagram in the numerical example which applied the specific numerical value to the 4th Embodiment, and is the figure which shows spherical aberration, astigmatism and distortion. It is a lateral aberration diagram in the numerical example which applied the specific numerical value to the 4th Embodiment. It is a figure which shows the lens structure of the 5th Embodiment of an image pickup lens. It is a longitudinal aberration diagram in the numerical example which applied the specific numerical value to the 5th Embodiment, and is the figure which shows spherical aberration, astigmatism and distortion. It is a lateral aberration diagram in the numerical example which applied the specific numerical value to the 5th Embodiment. It is a figure which shows the lens structure of the 6th Embodiment of an image pickup lens. It is a longitudinal aberration diagram in the numerical example which applied the specific numerical value to the 6th Embodiment, and is the figure which shows spherical aberration, astigmatism and distortion. It is a lateral aberration diagram in the numerical example which applied the specific numerical value to the 6th Embodiment. It is a figure which shows the lens structure of 7th Embodiment of an image pickup lens. It is a longitudinal aberration diagram in the numerical example which applied the specific numerical value to the 7th Embodiment, and is the figure which shows spherical aberration, astigmatism and distortion. It is a lateral aberration diagram in the numerical example which applied the specific numerical value to the 7th Embodiment. It is a figure which shows the lens structure of the 8th Embodiment of an image pickup lens. It is a longitudinal aberration diagram in the numerical example which applied the specific numerical value to the 8th Embodiment, and is the figure which shows spherical aberration, astigmatism and distortion. It is a lateral aberration diagram in the numerical example which applied the specific numerical value to the 8th Embodiment. It is a figure which shows the lens structure of the 9th Embodiment of an image pickup lens. It is a longitudinal aberration diagram in the numerical example which applied the specific numerical value to the 9th Embodiment, and is the figure which shows spherical aberration, astigmatism and distortion. It is a lateral aberration diagram in the numerical example which applied the specific numerical value to the 9th Embodiment. It is a figure which shows the lens structure of the tenth embodiment of an image pickup lens. FIG. 5 is a longitudinal aberration diagram in a numerical example in which specific numerical values are applied to the tenth embodiment, and is a diagram showing spherical aberration, astigmatism, and distortion. It is a lateral aberration diagram in the numerical example which applied the specific numerical value to the tenth embodiment. It is a block diagram which shows an example of an image pickup apparatus.

Hereinafter, a mode for implementing the present technology imaging lens and imaging device will be described.

[Configuration of imaging lens]
The imaging lens of the present technology consists of a first lens group, an aperture aperture and a second lens group arranged in order from the object side to the image side, and the first lens group is not arranged on both sides or one side in order from the object side to the image side. A first negative meniscus lens having a spherical shape with a convex surface facing the object side, a second negative meniscus lens having a convex surface facing the object side, and a single lens having a negative refractive power or from the object side to the image side. It has units arranged in negative and positive directions in order, and the second lens group has a positive lens group that moves from the image side to the object side when focusing from an infinity object to a short-range object. The conditional expression (1) and the conditional expression (2) are satisfied.
(1) 40.00 <νdL1 <96.00
(2) -10.0 <fL1 / f <-2.0
However,
νdL1: Abbe number of the d line of the first negative meniscus lens fL1: Focal length of the first negative meniscus lens f: Focal length of the entire system at infinity focusing.

The first lens group plays the role of a wide converter that secures sufficient back focus while increasing the angle of view in the entire optical system. The first lens group has a first negative meniscus lens whose convex surface is most oriented toward the object side. Since the first lens group plays the role of a wide converter, it is necessary to arrange the refractive power of the retrofocus type with the object side as the negative refractive power and the image side as the positive refractive power. In this case, by arranging the first negative meniscus lens having an aspherical shape such that the conic coefficient becomes smaller with respect to the aperture diaphragm, it becomes possible to satisfactorily correct distortion and curvature of field. It becomes possible to reduce the size of the first lens group.

Further, the first lens group includes a first negative meniscus lens having a convex surface facing the object side, a second negative meniscus lens having a convex surface facing the object side, and a negative refractive power in this order from the object side to the image side. It has a single lens with a lens or a unit in which negative and positive lenses are arranged in order from the object side to the image side. Since the first lens group plays the role of a wide converter, it is necessary to arrange the refractive power of the retrofocus type with the object side as the negative refractive power and the image side as the positive refractive power. By dividing the negative lens on the object side into a first negative meniscus lens, a second negative meniscus lens, and a unit, the negative refractive power can be divided, and various aberrations such as distortion and curvature of field can be satisfactorily reduced. It is possible to correct.

The conditional expression (1) defines the Abbe number of the first negative meniscus lens in a preferable range in order to satisfactorily correct the chromatic aberration of magnification.

If it falls below the lower limit of the conditional expression (1), the Abbe number of the first negative meniscus lens becomes small, and it becomes difficult to satisfactorily correct the chromatic aberration of magnification.

On the other hand, when the upper limit of the conditional equation (1) is exceeded, the Abbe number of the first negative meniscus lens increases, and in general, the refractive index tends to decrease, and the refractive index of the first negative meniscus lens decreases. This weakens the refractive power of the first negative meniscus lens, making it difficult to satisfactorily correct distortion and curvature of field.

Therefore, when the imaging lens satisfies the conditional equation (1), the Abbe number of the first negative meniscus lens is optimized, and chromatic aberration of magnification, distortion, and curvature of field can be satisfactorily corrected.

Note that distortion and curvature of field can be suppressed by setting the upper limit of the conditional expression (1) to 85.00, which is more preferable.

Further, by setting the lower limit value of the conditional expression (1) to 48.00, chromatic aberration of magnification can be suppressed, which is more preferable.

Conditional expression (2) plays the role of a wide converter of the first lens group, and in order to perform good aberration correction while increasing the angle of view of the first negative meniscus lens on the most object side of the first lens group. It defines a preferred range.

If it falls below the lower limit of the conditional expression (2), the negative refractive power of the first negative meniscus lens with respect to the refractive power of the entire system becomes weaker, so that the first negative lens group plays a role as a wide converter. The negative refractive power cannot be shared by the meniscus lens, the second negative meniscus lens, and the unit, and it becomes difficult to correct various aberrations such as distortion and curvature of field.

On the other hand, when the upper limit of the conditional equation (2) is exceeded, the refractive power of the first negative meniscus lens with respect to the refractive power of the entire system becomes strong, so that the negative refractive power of the first negative meniscus lens becomes extremely strong. , Distortion and astigmatism worsen, which is not preferable.

Therefore, when the imaging lens satisfies the condition equation (2), the negative refractive power of the first negative meniscus lens is optimized, and distortion, curvature of field, and astigmatism can be satisfactorily corrected. ..

It should be noted that by setting the lower limit value of the conditional expression (2) to -6.5, distortion and curvature of field can be suppressed, which is more preferable.

According to the imaging lens of this technology, by using a glass material with a high Abbe number for the lens having an aspherical surface and the most negative refractive power on the object side, various yields including chromatic aberration of magnification can be satisfactorily corrected. It is possible to provide a wide-angle lens capable of increasing the diameter.

[Structure of another imaging lens]
Another imaging lens of the present technology consists of a first lens group, an aperture aperture, and a second lens group arranged in order from the object side to the image side, and the first lens group is sequentially arranged from the object side to the image side to the object side. It has a first negative meniscus lens with a convex surface facing and a second negative meniscus lens with a convex surface facing the object side, and the first lens group includes a positive lens having an aspherical shape on both sides or one side and a positive lens. It has a lens unit composed of a lens having a negative refractive force closest to the object side of the lens to a lens closest to the object side of a positive lens, and the second lens group is from an infinity object to a short-range object. It has a positive lens group that moves from the image side to the object side when in focus, and satisfies the following conditional equations (3) and (4).
(3) -35.00 <fLN / fLP <-1.05
(4) 1.00 <dLP / dS <1.55
However,
fLN: Focal length of the lens unit fLP: Focal length of the positive lens in the first lens group dLP: Distance from the object side surface of the positive lens to the image plane in the first lens group dS: Distance from the aperture aperture to the image plane do.

Spherical aberration can be satisfactorily corrected by arranging a positive lens having an aspherical shape on both sides or one side of the first lens group near an aperture diaphragm having a high marginal ray with an axial angle of view. Further, by arranging this positive lens near the aperture diaphragm, the upper ray of the off-axis angle of view passes through the center of the lens and the lower ray passes around the lens, so that coma aberration can be satisfactorily corrected.

The first lens group has a lens unit composed of a lens having an aspherical shape on both sides or one side and having a negative refractive power closest to the object side of the positive lens to a lens closest to the object side of the positive lens. .. By arranging the lens unit on the object side of the positive lens having an aspherical shape on both sides or one side in this way, it is possible to enhance the correction effect of spherical aberration.

If it falls below the lower limit of the conditional expression (3), the refractive power of the positive lens having an aspherical shape on both sides or one side becomes extremely strong as compared with the lens unit, so that the spherical aberration in the whole system worsens. Further, in the vicinity of the aperture aperture, the refractive power of the positive lens having an aspherical shape on both sides or one side becomes too strong, so that the light rays incident on the second lens group are more converged, so that the spherical surface at the time of focusing Aberration fluctuation becomes large.

On the other hand, if the upper limit of the conditional expression (3) is exceeded, the refractive power of the positive lens having an aspherical shape on both sides or one side becomes extremely weak, and the effect as an aspherical lens becomes weak. Various aberrations cannot be corrected satisfactorily.

Therefore, when the imaging lens satisfies the condition equation (3), the refractive power of the positive lens having an aspherical shape on both sides or one side is optimized, and the fluctuation of spherical aberration during focusing can be suppressed and the spherical aberration can be suppressed. It is possible to satisfactorily correct various aberrations such as.

It is more preferable that the lower limit value of the conditional expression (3) is set to -35.00 to suppress chromatic aberration of magnification.

If the upper limit of the conditional expression (4) is exceeded, the distance from the positive lens having an aspherical shape on both sides or one side to the aperture diaphragm becomes long, and when a marginal ray having an axial angle of view is incident on this positive lens. In addition, since the light rays do not spread sufficiently, various aberrations such as spherical aberration cannot be satisfactorily corrected.

On the other hand, if it falls below the lower limit of the conditional expression (4), the distance from the positive lens having an aspherical shape on both sides or one side to the aperture diaphragm becomes too short, so that the lens structure cannot be established.

Therefore, when the imaging lens satisfies the condition equation (4), the distance from the positive lens having an aspherical shape on both sides or one side to the aperture diaphragm is optimized, and various aberrations such as spherical aberration are satisfactorily corrected. At the same time, the lens structure can be properly configured.

It should be noted that by setting the upper limit value of the conditional expression (4) to 1.50, various aberrations such as spherical aberration can be satisfactorily corrected, which is more preferable.

Further, by setting the upper limit value of the conditional expression (4) to 1.40, various aberrations such as spherical aberration can be corrected more satisfactorily, which is more preferable.

According to another imaging lens of the present technology, by appropriately defining the focal length of each lens in the first lens group, it is possible to increase the diameter while satisfactorily correcting various yields including chromatic aberration of magnification. It is possible to provide a wide-angle lens.

[Structure of an imaging lens according to one embodiment]
It is desirable that the following conditional expression (5) is satisfied for an imaging lens according to an embodiment of the present technology (including another present technology; the same shall apply hereinafter in the "imaging lens").
(5) 1.5 <fG2F / f <8.5
However,
fG2F: Focal length of the positive lens group in the second lens group f: Focal length of the entire system at infinity focusing.

The conditional expression (5) is a conditional expression for appropriately setting the focal length of the positive lens group that functions as the focus group in the second lens group.

If it falls below the lower limit of the conditional expression (5), the refractive power of the positive lens group becomes too strong, and the aberration generated in the positive lens group becomes large, and various aberrations such as spherical aberration cannot be corrected.

On the other hand, if the upper limit of the conditional expression (5) is exceeded, the refractive power of the positive lens group becomes too weak, so that the focus sensitivity cannot be obtained and the focus stroke becomes long, so that the image pickup lens must be miniaturized. Becomes difficult.

Therefore, when the imaging lens satisfies the condition equation (5), the focal length of the positive lens group that functions as the focus group is optimized, various aberrations such as spherical aberration can be satisfactorily corrected, and the focus stroke. Can be shortened to reduce the size of the imaging lens.

It should be noted that by setting the upper limit value of the conditional expression (5) to 6.5, the focus stroke can be shortened and the size can be reduced, which is more preferable.

Further, by setting the lower limit value of the conditional expression (5) to 2.5, various aberrations such as spherical aberration can be suppressed, which is more preferable.

It is desirable that the following conditional expression (6) is satisfied for the image pickup lens according to the embodiment of the present technology.
(6) 3 <| fG1 / fG2 |
However,
fG1: Focal length of the first lens group fG2: Focal length of the second lens group.

The conditional expression (6) is a conditional expression for appropriately setting the ratio of the refractive powers of the first lens group and the second lens group.

The first lens group plays the role of a wide converter that secures sufficient back focus while increasing the angle of view in the entire optical system, and emits incident light rays from the first lens group to the second lens group. By making it afocal, it is possible to suppress fluctuations in spherical aberration during focusing.

It should be noted that by setting the lower limit value of the conditional expression (6) to 4, various aberrations such as spherical aberration can be suppressed, which is more preferable.

It is desirable that the following conditional expression (7) is satisfied for the image pickup lens according to the embodiment of the present technology.
(7) 0.30 <fL1 / fL2 <2.50
However,
fL1: Focal length of the first negative meniscus lens fL2: Focal length of the second negative meniscus lens.

The first lens group acts as a wide converter, and the negative refractive power can be divided by dividing the negative lens on the object side into a first negative meniscus lens, a second negative meniscus lens, and a unit. , It is possible to correct various aberrations such as distortion and curvature of field. Further, the second negative meniscus lens must have a higher refractive power than the first negative meniscus lens.

If it falls below the lower limit of the conditional equation (7), the refractive power of one of the first negative meniscus lens and the second negative meniscus lens becomes weak, and distortion and curvature of field are corrected. I can't.

On the other hand, if the upper limit of the conditional expression (7) is exceeded, the refractive power of the first negative meniscus lens is weakened, so that it becomes difficult for the first negative meniscus lens to satisfactorily correct the chromatic aberration of magnification.

Therefore, when the imaging lens satisfies the conditional equation (7), the refractive powers of the first negative meniscus lens and the second negative meniscus lens are optimized, and distortion aberration and curvature of field are satisfactorily corrected. The first negative meniscus lens can satisfactorily correct the chromatic aberration of magnification.

It should be noted that by setting the upper limit value of the conditional expression (7) to 1.55, chromatic aberration of magnification can be suppressed, which is more preferable.

Further, by setting the lower limit value of the conditional expression (7) to 0.40, distortion and curvature of field can be suppressed, which is more preferable.

It is desirable that the following conditional expression (8) is satisfied for the image pickup lens according to the embodiment of the present technology.
(8) -1.5 <fG2 / fLA <-0.2
However,
fG2: Focal length of the second lens group fLA: Focal length of the negative air lens having the strongest refractive power in the second lens group.

In order to shorten the flange back and reduce the overall length, a negative refractive power is required in the second lens group, and the conditional equation (8) is based on the negative air lens in the second lens group and the second lens group. It is a condition for setting the ratio of.

If it falls below the lower limit of the conditional equation (8), the refractive power of the negative air lens in the second lens group becomes too strong with respect to the second lens group, so that spherical aberration and the like generated in the negative air lens occur. It becomes difficult to correct various aberrations.

On the other hand, if the upper limit of the conditional expression (8) is exceeded, the refractive power of the negative air lens in the second lens group becomes weaker than that in the second lens group. Therefore, the flange back should be shortened to reduce the size. Becomes difficult.

Therefore, when the imaging lens satisfies the condition equation (8), the refractive power of the negative air lens with respect to the second lens group is optimized, various aberrations such as spherical aberration can be satisfactorily corrected, and the flange back Can be shortened to reduce the size of the image pickup lens.

It should be noted that various aberrations such as spherical aberration can be suppressed by setting the lower limit value of the conditional expression (8) to −1.2, which is more preferable.

In the image pickup lens according to the embodiment of the present technology, the distance from the image plane side surface of the most image side lens in the second lens group to the image plane is set as the back focus, and the following conditional expression (9) is satisfied. It is desirable to do.
(9) 0.3 <BF / f <2.5
However,
BF: Back focus f: Focal length of the entire system when focusing at infinity.

If the upper limit of the conditional expression (9) is exceeded, the back focus becomes long, and the total length cannot be shortened.

On the other hand, if it falls below the lower limit of the conditional expression (9), it becomes difficult to secure a sufficient distance between the image plane and the lens on the image side, and the manufacturability deteriorates.

Therefore, if the image pickup lens satisfies the conditional expression (9), the back focus is shortened and the total length is shortened, so that the image pickup lens can be miniaturized.

It should be noted that by setting the upper limit value of the conditional expression (9) to 1.55, the back focus can be shortened and the total length can be shortened, which is more preferable.

Further, it is more preferable to set the lower limit value of the conditional expression (9) to 0.4 because a sufficient distance between the image plane and the lens on the image side can be secured and the manufacturability can be improved.

It is desirable that the following conditional expression (10) is satisfied for the image pickup lens according to the embodiment of the present technology.
(10) 2.3 <SL1 <4.6
However,
SL1: Specific density of the first negative meniscus lens [g / square centimeter]
And.

The specific gravity of glass glass material generally has a positive correlation with the refractive index, and the larger the specific gravity, the higher the refractive index tends to be. The conditional expression (10) is an expression for appropriately setting the specific gravity of the first negative meniscus lens in order to reduce the weight of the lens.

If it falls below the lower limit of the conditional equation (10), the refractive index of the first negative meniscus lens becomes too small, and the negative refractive power of the first negative meniscus lens becomes weak, so that the first negative Distortion and curvature of field cannot be properly corrected by the meniscus lens. On the other hand, if the upper limit of the conditional expression (10) is exceeded, the specific gravity of the first lens group, which occupies most of the volume in the entire system, becomes too high, and it becomes difficult to reduce the weight of the lens in the entire system.

Therefore, when the imaging lens satisfies the conditional equation (10), the refractive index of the first negative meniscus lens is optimized, distortion aberration and curvature of field can be satisfactorily corrected, and the lens in the entire system can be corrected. It is possible to reduce the weight of the lens.

In the imaging lens according to one embodiment of the present technology, it is desirable that the first lens group is fixed when focusing from an infinity object to a short-distance object.

The first lens group has a large volume and a large weight for the entire system, which is disadvantageous for speeding up focus drive.

Therefore, since the first lens group is fixed when focusing from an infinity object to a short-range object, the first lens group, which has a large volume and a large weight with respect to the entire system during focus drive, moves in the optical axis direction. Therefore, the focus drive can be speeded up.

[Numerical Example of Imaging Lens]
Hereinafter, specific embodiments of the imaging lens of the present technology and numerical examples in which specific numerical values are applied to the embodiments will be described with reference to drawings and tables.

The meanings of the symbols shown in the following tables and explanations are as shown below.

"R" is the paraxial radius of curvature of the i-th plane, "d" is the axial top-top spacing (thickness of the center of the lens or air spacing) between the i-th plane and the i + 1th plane, "nd" Is the refractive index on the d-line (λ = 587.6 nm) of the lens or the like starting from the i-th plane, and “νd” is the Abbe number on the d-line of the lens or the like starting from the i-th plane.

Regarding "r", "∞" indicates that the surface is a plane. Regarding "d", "variable" indicates that the interval is variable.

The aspherical surface is marked with * on the right side of the surface number, and the aperture diaphragm is marked with the description of "aperture" on the right side of the surface number.

"Κ" is a conical constant (conic constant), "A4", "A6", "A8", "A10", "A12" are 4th, 6th, 8th, 10th, and 12th aspherical coefficients, respectively. Is shown.

In each table showing the aspherical coefficient and the like below, "En" represents an exponential notation with a base of 10, that is, "10 minus nth power", for example, "0.12345E-05". "Represents" 0.12345 x (10 minus the fifth power) ".

Some of the imaging lenses used in each embodiment have an aspherical lens surface. For the aspherical shape, "x" is the distance (sag amount) in the optical axis direction from the apex of the lens surface, "y" is the height (image height) in the direction orthogonal to the optical axis direction, and "c" is the lens. Near-axis curvature at the apex (inverse of the radius of curvature), "κ" is the conical constant (conic constant), "A4", "A6", ... are the aspherical coefficients of the 4th, 6th, ... Then, it is defined by the following equation 1.

1, FIG. 4, FIG. 7, FIG. 10, FIG. 13, FIG. 16, FIG. 19, FIG. 22, FIG. 25, and FIG. 28 show the lens configuration at the infinity position of each embodiment.

2, FIG. 5, FIG. 8, FIG. 11, FIG. 14, FIG. 17, FIG. 20, FIG. 23, FIG. 26, and FIG. 29 show spherical aberration diagrams and astigmatism diagrams at the infinity position and the closest position of each embodiment. , Distortion aberration diagram is shown.

FIG. 3, FIG. 6, FIG. 9, FIG. 12, FIG. 15, FIG. 18, FIG. 21, FIG. 24, FIG. 27, and FIG. 30 show transverse aberration diagrams at the infinity position and the closest position of each embodiment. The left column shows the lateral aberration in the tangier luminous flux (meridional coma aberration), and the right column shows the lateral aberration in the sagittal luminous flux (sagittal coma aberration).

<First Embodiment>
FIG. 1 shows the lens configuration of the image pickup lens 1 according to the first embodiment of the present technology.

The imaging lens 1 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, which are arranged in order from the object side to the image side.

The first lens group G1 includes a first negative meniscus lens L1 having a convex surface facing the object side, a second negative meniscus lens L2 having a convex surface facing the object side, and a negative lens having concave surfaces on both sides, in order from the object side to the image side. It is composed of L3, a positive lens L4 having convex surfaces on both sides, a negative lens L5 having concave surfaces on both sides, a positive lens L6 having convex surfaces on both sides, and a positive lens L7 having convex surfaces on both sides.

The first negative meniscus lens L1 and the positive lens L7 are aspherical lenses having an aspherical shape formed on both sides. The negative lens L5 and the positive lens L6 are bonded together to form a bonded lens, and the negative lens L5 and the positive lens L6 form a lens unit LN. The positive lens L7 is configured as a positive lens LP having an aspherical shape formed on both sides.

The first lens group G1 consists of seven lenses and six lens components.

The second lens group G2 includes, in order from the object side to the image side, a positive lens L8 with convex surfaces on both sides, a positive lens L9 with convex surfaces on both sides, a negative lens L10 with concave surfaces on both sides, a positive lens L11 with convex surfaces on both sides, and a negative lens L12 with concave surfaces on both sides. It is composed of a negative lens L13 having concave surfaces on both sides and a positive meniscus lens L14 having a convex surface facing the image side.

The positive lens L9 and the negative lens L10 are bonded together to form a bonded lens. The negative lens L13 is an aspherical lens having an aspherical shape formed on both sides.

The second lens group G2 consists of seven lenses and six lens components.

The six lenses from the positive lens L8 to the negative lens L13 are configured as a positive lens group G2F that moves from the image side to the object side when focusing from an infinity object to a short-distance object. However, at the time of focusing, the front and rear may be moved at different movement ratios with an air interval formed in the second lens group G2.

Further, the air gap between the negative lens L12 and the negative lens L13 functions as a negative air lens LA having the strongest refractive power in the second lens group G2.

Table 1 shows the lens data of Numerical Example 1 in which specific numerical values are applied to the image pickup lens 1.

Table 2 shows the focal length f, the F number Fno, the half angle of view ω, the image height Y, and the total optical length L of Numerical Example 1.

When focusing between infinity and the closest (250 mm), the distance between the aperture stop S and the positive lens L8 and the distance between the negative lens L13 and the positive meniscus lens L14 change. Numerical values Table 3 shows the infinity and the closest variable spacing of each surface spacing in Example 1.

Numerical values Table 4 shows the 4th, 6th, 8th, 10th, and 12th aspherical coefficients A4, A6, A8, A10, and A12 of the aspherical surface in Example 1 together with the conical constant κ.

Numerical values Table 5 shows the focal lengths of each lens group in Example 1.

FIG. 2 is a longitudinal aberration diagram of Numerical Example 1, and FIG. 3 is a lateral aberration diagram of Numerical Example 1. In FIG. 2, the solid line shows the value of the d line (587.56 nm), the dotted line shows the value of the c line (656.27 nm), and the alternate long and short dash line shows the value of the g line (435.84 nm). In the astigmatism, the solid line shows the value of the sagittal image plane of the d line, the broken line shows the value of the meridional image plane of the d line, and the distortion shows the value of the d line. In FIG. 3, the solid line indicates the value of the d line, the dotted line indicates the value of the c line, the alternate long and short dash line indicates the value of the g line, and Y'is the image height on the imaging surface.

With the above configuration, the image pickup lens 1 is miniaturized while realizing a large aperture of F number 1.85.

Further, from each aberration diagram, it is clear that the numerical embodiment 1 has various aberrations corrected well and has excellent imaging performance.

<Second embodiment>
FIG. 4 shows the lens configuration of the image pickup lens 2 in the second embodiment of the present technology.

The imaging lens 2 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, which are arranged in order from the object side to the image side.

The first lens group G1 includes a first negative meniscus lens L1 having a convex surface facing the object side, a second negative meniscus lens L2 having a convex surface facing the object side, and a negative lens having concave surfaces on both sides, in order from the object side to the image side. It is composed of L3, a positive meniscus lens L4 with a convex surface facing the object side, a negative lens L5 with concave surfaces on both sides, a positive lens L6 with convex surfaces on both sides, and a positive lens L7 with convex surfaces on both sides.

The first negative meniscus lens L1 and the positive lens L7 are aspherical lenses having an aspherical shape formed on both sides. The negative lens L3 and the positive meniscus lens L4 are bonded together to form a bonded lens, and are configured as a unit in which negative and positive lenses are arranged in order from the object side to the image side. The negative lens L5 and the positive lens L6 are bonded together to form a bonded lens, and the negative lens L5 and the positive lens L6 form a lens unit LN. The positive lens L7 is configured as a positive lens LP having an aspherical shape formed on both sides.

The first lens group G1 consists of seven lenses and five lens components.

The second lens group G2 includes a positive lens L8 with convex surfaces on both sides, a positive lens L9 with convex surfaces on both sides, a negative lens L10 with concave surfaces on both sides, a positive lens L11 with convex surfaces on both sides, and a negative lens L12 with concave surfaces on both sides, in order from the object side to the image side. It is composed of negative lenses L13 having concave surfaces on both sides.

The second lens group G2 consists of 6 lenses and 5 lens components.

Table 6 shows the lens data of Numerical Example 2 in which specific numerical values are applied to the image pickup lens 2.

Table 7 shows the focal length f, the F number Fno, the half angle of view ω, the image height Y, and the total optical length L of Numerical Example 2.

When focusing between infinity and the closest (250 mm), the distance between the aperture stop S and the positive lens L8 and the distance between the negative lens L13 and the image plane IMG change. Numerical values Table 8 shows the infinity and the closest variable spacing of each surface spacing in Example 2.

Table 9 shows the 4th, 6th, 8th, 10th, and 12th aspherical coefficients A4, A6, A8, A10, and A12 of the aspherical surface in Numerical Example 2 together with the conical constant κ.

Numerical values Table 10 shows the focal lengths of each lens group in Example 2.

FIG. 5 is a longitudinal aberration diagram of Numerical Example 2, and FIG. 6 is a lateral aberration diagram of Numerical Example 2. In FIG. 5, the solid line shows the value of the d line (587.56 nm), the dotted line shows the value of the c line (656.27 nm), and the alternate long and short dash line shows the value of the g line (435.84 nm). In the astigmatism, the solid line shows the value of the sagittal image plane of the d line, the broken line shows the value of the meridional image plane of the d line, and the distortion shows the value of the d line. In FIG. 6, the solid line indicates the value of the d line, the dotted line indicates the value of the c line, the alternate long and short dash line indicates the value of the g line, and Y'is the image height on the imaging surface.

With the above configuration, the image pickup lens 2 is miniaturized while realizing a large aperture of F number 2.06.

Further, from each aberration diagram, it is clear that Numerical Example 2 has various aberrations corrected well and has excellent imaging performance.

<Third embodiment>
FIG. 7 shows the lens configuration of the image pickup lens 3 according to the third embodiment of the present technology.

The image pickup lens 3 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 arranged in order from the object side to the image side.

The first lens group G1 consists of seven lenses and six lens components.

The second lens group G2 includes, in order from the object side to the image side, a positive lens L8 with convex surfaces on both sides, a positive lens L9 with convex surfaces on both sides, a negative lens L10 with concave surfaces on both sides, a positive lens L11 with convex surfaces on both sides, and a negative lens L12 with concave surfaces on both sides. It is composed of a negative meniscus lens L13 with a convex surface facing the image side and a positive lens L14 with convex surfaces on both sides.

The positive lens L9 and the negative lens L10 are bonded together to form a bonded lens. The negative meniscus lens L13 is an aspherical lens having an aspherical shape formed on both sides.

The second lens group G2 consists of seven lenses and six lens components.

The six lenses from the positive lens L8 to the negative meniscus lens L13 are configured as a positive lens group G2F that moves from the image side to the object side when focusing from an infinity object to a short-range object. However, at the time of focusing, the front and rear may be moved at different movement ratios with an air interval formed in the second lens group G2.

Further, the air gap between the negative lens L12 and the negative meniscus lens L13 functions as a negative air lens LA having the strongest refractive power in the second lens group G2.

Table 11 shows the lens data of Numerical Example 3 in which specific numerical values are applied to the image pickup lens 3.

Table 12 shows the focal length f, the F number Fno, the half angle of view ω, the image height Y, and the total optical length L of Numerical Example 3.

When focusing between infinity and the closest (250 mm), the distance between the aperture stop S and the positive lens L8 and the distance between the negative meniscus lens L13 and the positive lens L14 change. Numerical values Table 13 shows the infinity and the closest variable spacing of each surface spacing in Example 3.

Numerical values Table 14 shows the 4th, 6th, 8th, 10th, and 12th aspherical coefficients A4, A6, A8, A10, and A12 of the aspherical surface in Example 3 together with the conical constant κ.

Numerical values Table 15 shows the focal lengths of each lens group in Example 3.

FIG. 8 is a longitudinal aberration diagram of Numerical Example 3, and FIG. 9 is a lateral aberration diagram of Numerical Example 3. In FIG. 8, the solid line shows the value of the d line (587.56 nm), the dotted line shows the value of the c line (656.27 nm), and the alternate long and short dash line shows the value of the g line (435.84 nm). In the astigmatism, the solid line shows the value of the sagittal image plane of the d line, the broken line shows the value of the meridional image plane of the d line, and the distortion shows the value of the d line. In FIG. 9, the solid line indicates the value of the d line, the dotted line indicates the value of the c line, the alternate long and short dash line indicates the value of the g line, and Y'is the image height on the imaging surface.

With the above configuration, the image pickup lens 3 is miniaturized while realizing a large aperture of F number 1.85.

Further, from each aberration diagram, it is clear that Numerical Example 3 has various aberrations corrected well and has excellent imaging performance.

<Fourth Embodiment>
FIG. 10 shows the lens configuration of the image pickup lens 4 according to the fourth embodiment of the present technology.

The image pickup lens 4 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 arranged in order from the object side to the image side.

The first lens group G1 consists of seven lenses and five lens components.

The second lens group G2 includes, in order from the object side to the image side, a positive lens L8 having convex surfaces on both sides, a positive lens L9 having convex surfaces on both sides, a negative lens L10 having concave surfaces on both sides, a positive lens L11 having convex surfaces on both sides, and a negative lens L12 having concave surfaces on both sides. It is composed of a negative lens L13 having concave surfaces on both sides and a positive meniscus lens L14 having a convex surface facing the image side.

The second lens group G2 consists of seven lenses and six lens components.

Table 16 shows the lens data of Numerical Example 4 in which specific numerical values are applied to the image pickup lens 4.

Table 17 shows the focal length f, the F number Fno, the half angle of view ω, the image height Y, and the total optical length L of Numerical Example 4.

When focusing between infinity and the closest (250 mm), the distance between the aperture stop S and the positive lens L8 and the distance between the negative lens L13 and the positive meniscus lens L14 change. Numerical values Table 18 shows the infinity and the closest variable spacing of each surface spacing in Example 4.

Table 19 shows the 4th, 6th, 8th, 10th, and 12th aspherical coefficients A4, A6, A8, A10, and A12 of the aspherical surface in Numerical Example 4 together with the conical constant κ.

Numerical values Table 20 shows the focal lengths of each lens group in Example 4.

FIG. 11 is a longitudinal aberration diagram of Numerical Example 4, and FIG. 12 is a transverse aberration diagram of Numerical Example 4. In FIG. 11, the solid line shows the value of the d line (587.56 nm), the dotted line shows the value of the c line (656.27 nm), and the alternate long and short dash line shows the value of the g line (435.84 nm). In the astigmatism, the solid line shows the value of the sagittal image plane of the d line, the broken line shows the value of the meridional image plane of the d line, and the distortion shows the value of the d line. In FIG. 12, the solid line indicates the value of the d line, the dotted line indicates the value of the c line, the alternate long and short dash line indicates the value of the g line, and Y'is the image height on the imaging surface.

With the above configuration, the image pickup lens 4 is miniaturized while realizing a large aperture of F number 2.11.

Further, from each aberration diagram, it is clear that the numerical embodiment 4 has various aberrations corrected well and has excellent imaging performance.

<Fifth Embodiment>
FIG. 13 shows the lens configuration of the image pickup lens 5 according to the fifth embodiment of the present technology.

The image pickup lens 5 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 arranged in order from the object side to the image side.

The first lens group G1 includes a first negative meniscus lens L1 having a convex surface facing the object side, a second negative meniscus lens L2 having a convex surface facing the object side, and negative lenses having concave surfaces on both sides, in order from the object side to the image side. It is composed of L3, a positive meniscus lens L4 having a convex surface facing the object side, a negative lens L5 having concave surfaces on both sides, a positive meniscus lens L6 having a convex surface facing the object side, and a positive lens L7 having convex surfaces on both sides.

The first negative meniscus lens L1 and the positive lens L7 are aspherical lenses having an aspherical shape formed on both sides. The negative lens L3 and the positive meniscus lens L4 are bonded together to form a bonded lens, and are configured as a unit in which negative and positive lenses are arranged in order from the object side to the image side. The negative lens L5 and the positive meniscus lens L6 are bonded together to form a bonded lens, and the negative lens L5 and the positive meniscus lens L6 form a lens unit LN. The positive lens L7 is configured as a positive lens LP having an aspherical shape formed on both sides.

The first lens group G1 consists of seven lenses and five lens components.

The second lens group G2 includes a positive lens L8 with convex surfaces on both sides, a positive meniscus lens L9 with convex surfaces facing the image side, a negative lens L10 with concave surfaces on both sides, a positive lens L11 with convex surfaces on both sides, and concave surfaces on both sides, in order from the object side to the image side. It is composed of a negative lens L12, a negative lens L13 with concave surfaces on both sides, and a positive meniscus lens L14 with a convex surface facing the image side.

The positive meniscus lens L9 and the negative lens L10 are bonded together to form a bonded lens. The negative lens L13 is an aspherical lens having an aspherical shape formed on both sides.

The second lens group G2 consists of seven lenses and six lens components.

Table 21 shows the lens data of Numerical Example 5 in which specific numerical values are applied to the image pickup lens 5.

Table 22 shows the focal length f, the F number Fno, the half angle of view ω, the image height Y, and the total optical length L of Numerical Example 5.

When focusing between infinity and the closest (250 mm), the distance between the aperture stop S and the positive lens L8 and the distance between the negative lens L13 and the positive meniscus lens L14 change. Numerical values Table 23 shows the infinity and the closest variable spacing of each surface spacing in Example 5.

Numerical values Table 24 shows the 4th, 6th, 8th, 10th, and 12th aspherical coefficients A4, A6, A8, A10, and A12 of the aspherical surface in Example 5 together with the conical constant κ.

Numerical values Table 25 shows the focal lengths of each lens group in Example 5.

FIG. 14 is a longitudinal aberration diagram of Numerical Example 5, and FIG. 15 is a transverse aberration diagram of Numerical Example 5. In FIG. 14, the solid line shows the value of the d line (587.56 nm), the dotted line shows the value of the c line (656.27 nm), and the alternate long and short dash line shows the value of the g line (435.84 nm). In the astigmatism, the solid line shows the value of the sagittal image plane of the d line, the broken line shows the value of the meridional image plane of the d line, and the distortion shows the value of the d line. In FIG. 15, the solid line indicates the value of the d line, the dotted line indicates the value of the c line, the alternate long and short dash line indicates the value of the g line, and Y'is the image height on the imaging surface.

With the above configuration, the image pickup lens 5 is miniaturized while realizing a large aperture of F number 2.47.

Further, from each aberration diagram, it is clear that the numerical embodiment 5 has various aberrations corrected well and has excellent imaging performance.

<Sixth Embodiment>
FIG. 16 shows the lens configuration of the image pickup lens 6 according to the sixth embodiment of the present technology.

The image pickup lens 6 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, which are arranged in order from the object side to the image side.

The first lens group G1 has a first negative meniscus lens L1 having a convex surface facing the object side, a second negative meniscus lens L2 having a convex surface facing the object side, and a convex surface toward the object side in order from the object side to the image side. It is composed of a negative meniscus lens L3 directed, a positive meniscus lens L4 with a convex surface facing the object side, a negative lens L5 with concave surfaces on both sides, a positive lens L6 with convex surfaces on both sides, and a positive lens L7 with convex surfaces on both sides.

The first lens group G1 consists of seven lenses and six lens components.

The second lens group G2 includes a positive lens L8 with convex surfaces on both sides, a positive lens L9 with convex surfaces on both sides, a negative lens L10 with concave surfaces on both sides, a positive lens L11 with convex surfaces on both sides, and a negative lens L12 with concave surfaces on both sides, in order from the object side to the image side. It is composed of a negative meniscus lens L13 with a convex surface facing the image side.

The second lens group G2 consists of 6 lenses and 5 lens components.

Table 26 shows the lens data of Numerical Example 6 in which specific numerical values are applied to the image pickup lens 6.

Table 27 shows the focal length f, the F number Fno, the half angle of view ω, the image height Y, and the total optical length L of Numerical Example 6.

When focusing between infinity and the closest (250 mm), the distance between the aperture stop S and the positive lens L8 and the distance between the negative meniscus lens L13 and the image plane IMG change. Numerical values Table 28 shows the infinity and the closest variable spacing of each surface spacing in Example 6.

Table 29 shows the 4th, 6th, 8th, 10th, and 12th aspherical coefficients A4, A6, A8, A10, and A12 of the aspherical surface in Numerical Example 6 together with the conical constant κ.

Numerical values Table 30 shows the focal lengths of each lens group in Example 6.

FIG. 17 is a longitudinal aberration diagram of Numerical Example 6, and FIG. 18 is a transverse aberration diagram of Numerical Example 6. In FIG. 17, the solid line shows the value of the d line (587.56 nm), the dotted line shows the value of the c line (656.27 nm), and the alternate long and short dash line shows the value of the g line (435.84 nm). In the astigmatism, the solid line shows the value of the sagittal image plane of the d line, the broken line shows the value of the meridional image plane of the d line, and the distortion shows the value of the d line. In FIG. 18, the solid line indicates the value of the d line, the dotted line indicates the value of the c line, the alternate long and short dash line indicates the value of the g line, and Y'is the image height on the imaging surface.

With the above configuration, the image pickup lens 6 is miniaturized while realizing a large aperture of F number 1.85.

Further, from each aberration diagram, it is clear that the numerical embodiment 6 has various aberrations corrected well and has excellent imaging performance.

<7th embodiment>
FIG. 19 shows the lens configuration of the image pickup lens 7 according to the seventh embodiment of the present technology.

The image pickup lens 7 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 arranged in order from the object side to the image side.

The first lens group G1 consists of seven lenses and six lens components.

The second lens group G2 consists of seven lenses and six lens components.

Table 31 shows the lens data of Numerical Example 7 in which specific numerical values are applied to the image pickup lens 7.

Table 32 shows the focal length f, the F number Fno, the half angle of view ω, the image height Y, and the total optical length L of Numerical Example 7.

When focusing between infinity and the closest (250 mm), the distance between the aperture stop S and the positive lens L8 and the distance between the negative meniscus lens L13 and the positive lens L14 change. Numerical values Table 33 shows the infinity and the closest variable spacing of each surface spacing in Example 7.

Numerical values Table 34 shows the 4th, 6th, 8th, 10th, and 12th aspherical coefficients A4, A6, A8, A10, and A12 of the aspherical surface in Example 7 together with the conical constant κ.

Numerical values Table 35 shows the focal lengths of each lens group in Example 7.

FIG. 20 is a longitudinal aberration diagram of Numerical Example 7, and FIG. 21 is a transverse aberration diagram of Numerical Example 7. In FIG. 20, the solid line shows the value of the d line (587.56 nm), the dotted line shows the value of the c line (656.27 nm), and the alternate long and short dash line shows the value of the g line (435.84 nm). In the astigmatism, the solid line shows the value of the sagittal image plane of the d line, the broken line shows the value of the meridional image plane of the d line, and the distortion shows the value of the d line. In FIG. 21, the solid line indicates the value of the d line, the dotted line indicates the value of the c line, the alternate long and short dash line indicates the value of the g line, and Y'is the image height on the imaging surface.

With the above configuration, the image pickup lens 7 is miniaturized while realizing a large aperture of F number 1.85.

Further, from each aberration diagram, it is clear that the numerical embodiment 7 has various aberrations corrected well and has excellent imaging performance.

<8th embodiment>
FIG. 22 shows the lens configuration of the image pickup lens 8 according to the eighth embodiment of the present technology.

The image pickup lens 8 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, which are arranged in order from the object side to the image side.

The first negative meniscus lens L1 and the positive lens L7 are aspherical lenses having an aspherical shape formed on both sides. The lens unit LN is composed of a negative lens L5 and a positive lens L6. The positive lens L7 is configured as a positive lens LP having an aspherical shape formed on both sides.

The first lens group G1 consists of seven lenses and seven lens components.

The second lens group G2 consists of seven lenses and six lens components.

Table 1 shows the lens data of Numerical Example 8 in which specific numerical values are applied to the image pickup lens 8.

Table 37 shows the focal length f, the F number Fno, the half angle of view ω, the image height Y, and the total optical length L of Numerical Example 8.

When focusing between infinity and the closest (250 mm), the distance between the aperture stop S and the positive lens L8 and the distance between the negative lens L13 and the positive meniscus lens L14 change. Numerical values Table 38 shows the infinity and the closest variable spacing of each surface spacing in Example 8.

Numerical values Table 39 shows the 4th, 6th, 8th, 10th, and 12th aspherical coefficients A4, A6, A8, A10, and A12 of the aspherical surface in Example 8 together with the conical constant κ.

Numerical values Table 40 shows the focal lengths of each lens group in Example 8.

FIG. 23 is a longitudinal aberration diagram of Numerical Example 8 and FIG. 24 is a lateral aberration diagram of Numerical Example 8. In FIG. 23, the solid line shows the value of the d line (587.56 nm), the dotted line shows the value of the c line (656.27 nm), and the alternate long and short dash line shows the value of the g line (435.84 nm). In the astigmatism, the solid line shows the value of the sagittal image plane of the d line, the broken line shows the value of the meridional image plane of the d line, and the distortion shows the value of the d line. In FIG. 24, the solid line indicates the value of the d line, the dotted line indicates the value of the c line, the alternate long and short dash line indicates the value of the g line, and Y'is the image height on the imaging surface.

With the above configuration, the image pickup lens 8 is miniaturized while realizing a large aperture of F number 1.86.

Further, from each aberration diagram, it is clear that the numerical embodiment 8 has various aberrations corrected well and has excellent imaging performance.

<9th embodiment>
FIG. 25 shows the lens configuration of the image pickup lens 9 according to the ninth embodiment of the present technology.

The image pickup lens 9 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 arranged in order from the object side to the image side.

The first lens group G1 consists of seven lenses and six lens components.

The second lens group G2 includes, in order from the object side to the image side, a positive lens L8 having convex surfaces on both sides, a positive lens L9 having convex surfaces on both sides, a negative lens L10 having concave surfaces on both sides, a positive lens L11 having convex surfaces on both sides, and a negative lens L12 having concave surfaces on both sides. It is composed of a negative lens L13 having concave surfaces on both sides and a positive lens L14 having convex surfaces on both sides.

The second lens group G2 consists of seven lenses and six lens components.

Table 41 shows the lens data of the numerical value Example 1 in which specific numerical values are applied to the image pickup lens 9.

Table 42 shows the focal length f, the F number Fno, the half angle of view ω, the image height Y, and the total optical length L of Numerical Example 1.

When focusing between infinity and the closest (250 mm), the distance between the aperture stop S and the positive lens L8 and the distance between the negative meniscus lens L13 and the positive meniscus lens L14 change. Numerical values Table 43 shows the infinity and the closest variable spacing of each surface spacing in Example 1.

Numerical values Table 44 shows the 4th, 6th, 8th, 10th, and 12th aspherical coefficients A4, A6, A8, A10, and A12 of the aspherical surface in Example 1 together with the conical constant κ.

Numerical values Table 45 shows the focal lengths of each lens group in Example 1.

FIG. 26 is a longitudinal aberration diagram of Numerical Example 1, and FIG. 27 is a transverse aberration diagram of Numerical Example 1. In FIG. 26, the solid line shows the value of the d line (587.56 nm), the dotted line shows the value of the c line (656.27 nm), and the alternate long and short dash line shows the value of the g line (435.84 nm). In the astigmatism, the solid line shows the value of the sagittal image plane of the d line, the broken line shows the value of the meridional image plane of the d line, and the distortion shows the value of the d line. In FIG. 27, the solid line indicates the value of the d line, the dotted line indicates the value of the c line, the alternate long and short dash line indicates the value of the g line, and Y'is the image height on the imaging surface.

With the above configuration, the image pickup lens 9 is miniaturized while realizing a large aperture of F number 1.85.

<10th embodiment>
FIG. 28 shows the lens configuration of the image pickup lens 10 according to the tenth embodiment of the present technology.

The imaging lens 10 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, which are arranged in order from the object side to the image side.

The first lens group G1 includes a first negative meniscus lens L1 having a convex surface facing the object side, a second negative meniscus lens L2 having a convex surface facing the object side, and negative lenses having concave surfaces on both sides, in order from the object side to the image side. It is composed of L3, a positive lens L4 with convex surfaces on both sides, a negative lens L5 with concave surfaces on both sides, a positive meniscus lens L6 with convex surfaces facing the object side, and a positive lens L7 with convex surfaces on both sides.

The first negative meniscus lens L1 and the negative lens L3 are aspherical lenses having an aspherical shape formed on both sides. The negative lens L5 and the positive lens L6 are bonded together to form a bonded lens.

The first lens group G1 consists of seven lenses and six lens components.

The second lens group G2 includes, in order from the object side to the image side, a positive lens L8 with convex surfaces on both sides, a negative lens L9 with concave surfaces on both sides, a positive lens L10 with convex surfaces on both sides, a negative lens L11 with concave surfaces on both sides, and a positive lens L12 with convex surfaces on both sides. It is composed of a negative lens L13 having concave surfaces on both sides, a negative meniscus lens L14 having a convex surface facing the image side, and a negative meniscus lens L15 having a convex surface facing the image side.

The positive lens L8 and the negative lens L9 are bonded together to form a bonded lens, and the positive lens L10 and the negative lens L11 are bonded together to form a bonded lens. The negative lens L14 is an aspherical lens having an aspherical shape formed on both sides.

The second lens group G2 consists of eight lenses and six lens components.

The seven lenses from the positive lens L8 to the negative lens L14 are configured as a positive lens group G2F that moves from the image side to the object side when focusing from an infinity object to a short-distance object. However, at the time of focusing, the front and rear may be moved at different movement ratios with an air interval formed in the second lens group G2.

Further, the air gap between the negative lens L13 and the negative lens L14 functions as a negative air lens LA having the strongest refractive power in the second lens group G2.

Table 46 shows the lens data of Numerical Example 10 in which specific numerical values are applied to the image pickup lens 10.

Table 47 shows the focal length f, the F number Fno, the half angle of view ω, the image height Y, and the total optical length L of Numerical Example 10.

When focusing between infinity and the closest (190 mm), the distance between the aperture stop S and the positive lens L8 and the distance between the negative lens L14 and the negative meniscus lens L15 change. Numerical values Table 48 shows the infinity and the closest variable spacing of each surface spacing in Example 10.

Numerical values Table 49 shows the 4th, 6th, 8th, 10th, and 12th aspherical coefficients A4, A6, A8, A10, and A12 of the aspherical surface in Example 10 together with the conical constant κ.

Numerical values Table 50 shows the focal lengths of each lens group in Example 10.

FIG. 29 is a longitudinal aberration diagram of Numerical Example 10, and FIG. 30 is a transverse aberration diagram of Numerical Example 10. In FIG. 29, the solid line shows the value of the d line (587.56 nm), the dotted line shows the value of the c line (656.27 nm), and the alternate long and short dash line shows the value of the g line (435.84 nm). In the astigmatism, the solid line shows the value of the sagittal image plane of the d line, the broken line shows the value of the meridional image plane of the d line, and the distortion shows the value of the d line. In FIG. 30, the solid line indicates the value of the d line, the dotted line indicates the value of the c line, the alternate long and short dash line indicates the value of the g line, and Y'is the image height on the imaging surface.

With the above configuration, the image pickup lens 10 is miniaturized while realizing a large aperture of F number 2.06.

Further, from each aberration diagram, it is clear that the numerical embodiment 10 has various aberrations corrected well and has excellent imaging performance.

[Each value of the conditional expression of the imaging lens]
Hereinafter, each value of the conditional expression of the imaging lens of the present technology will be described.

Table 51 shows the values of the conditional expressions (1) to (10) in the numerical examples 1 to 10 of the image pickup lens 1 to the image pickup lens 10.

As is clear from Table 51, the image pickup lens 1 to the image pickup lens 10 are designed to satisfy the conditional expression (1) to the conditional expression (10).

[Configuration of imaging device]
In the imaging device of the present technology, the imaging lens consists of a first lens group, an aperture aperture and a second lens group arranged in order from the object side to the image side, and the first lens group is arranged on both sides in order from the object side to the image side. Alternatively, a first negative meniscus lens having an aspherical shape on one side and having a convex surface facing the object side, a second negative meniscus lens having a convex surface facing the object side, and a single lens having a negative refractive power or the object side. The second lens group has a positive lens group that moves from the image side to the object side when focusing from an infinity object to a short-range object. Then, the following conditional expression (1) and conditional expression (2) are satisfied.
(1) 40.00 <νdL1 <96.00
(2) -10.0 <fL1 / f <-2.0
However,
νdL1: Abbe number of the d line of the first negative meniscus lens fL1: Focal length of the first negative meniscus lens f: Focal length of the entire system at infinity focusing.

Therefore, the image pickup device of the present technology distorts by arranging a first negative meniscus lens having an aspherical shape such that the conic coefficient becomes smaller with respect to the aperture diaphragm in the image pickup lens, similarly to the image pickup lens of the present technology. It is possible to satisfactorily correct aberrations and curvature of field, and it is possible to reduce the size of the first lens group.

Further, similarly to the image pickup lens of the present technology, in the image pickup lens, the negative refractive power can be divided by dividing the negative lens on the object side into a first negative meniscus lens, a second negative meniscus lens, and a unit. , It is possible to satisfactorily correct various aberrations such as distortion and curvature of field.

Further, in the image pickup apparatus, when the image pickup lens satisfies the condition equation (1), the Abbe number of the first negative meniscus lens is optimized, and the chromatic aberration of magnification, the distortion, and the curvature of field can be satisfactorily corrected. can.

Furthermore, in the imaging device, when the imaging lens satisfies the condition equation (2), the negative refractive power of the first negative meniscus lens is optimized, and distortion, curvature of field, and astigmatism are satisfactorily suppressed. It can be corrected.

As described above, according to the imaging device of the present technology, by using a glass material having a high Abbe number for a lens having a plurality of aspherical surfaces and having the most negative refractive power on the object side, various yields including chromatic aberration of magnification can be obtained. It is possible to provide a wide-angle lens capable of increasing the diameter while making good corrections.

[Structure of another imaging lens]
In another technology imaging lens, the imaging lens is composed of a first lens group, an aperture aperture and a second lens group arranged in order from the object side to the image side, and the first lens group is sequentially arranged from the object side to the image side. The first negative meniscus lens has a first negative meniscus lens with a convex surface facing the object side and a second negative meniscus lens with a convex surface facing the object side, and the first lens group has a positive spherical shape on both sides or one side. It has a lens and a lens unit composed of a lens having a negative refractive force closest to the object side of the positive lens to a lens closest to the object side of the positive lens, and the second lens group is close to an infinity object. It has a positive lens group that moves from the image side to the object side when focusing on a distance object, and satisfies the following conditional equations (3) and (4).
(3) -35.00 <fLN / fLP <-1.05
(4) 1.00 <dLP / dS <1.55
However,
fLN: Focal length of the lens unit fLP: Focal length of the positive lens in the first lens group dLP: Distance from the object side surface of the positive lens to the image plane in the first lens group dS: Distance from the aperture aperture to the image plane do.

Therefore, another image pickup device of the present technology is arranged in the vicinity of the positive lens aperture diaphragm having an aspherical shape on both sides or one side of the first lens group in the image pickup lens, similarly to another image pickup lens of the present technology. Since the upper light beam at the outer angle of view passes through the center of the lens and the lower light beam passes around the lens, coma can be satisfactorily corrected.

In addition, another technology imaging device, like another technology imaging lens, has spherical aberration by arranging the lens unit on the object side of a positive lens having an aspherical shape on both sides or one side of the imaging lens. It is possible to enhance the correction effect.

Further, in the image pickup apparatus, when the image pickup lens satisfies the condition equation (3), the refractive power of the positive lens having an aspherical shape on both sides or one side is optimized, and the fluctuation of spherical aberration during focusing can be suppressed. At the same time, various aberrations such as spherical aberration can be satisfactorily corrected.

Furthermore, in the imaging device, when the imaging lens satisfies the condition equation (4), the distance from the positive lens having an aspherical shape on both sides or one side to the aperture diaphragm is optimized, and various aberrations such as spherical aberration are eliminated. It can be corrected satisfactorily and an appropriate lens structure can be constructed.

As described above, according to another imaging device of the present technology, by appropriately defining the focal length of each lens or the like in the first lens group, various yields including chromatic aberration of magnification can be satisfactorily corrected. It is possible to provide a wide-angle lens capable of increasing the diameter.

[One Embodiment of an Imaging Device]
FIG. 31 shows a block diagram of a digital still camera according to an embodiment of the imaging device of the present technology.

The image pickup device (digital still camera) 100 includes an image pickup element 15 having a photoelectric conversion function for converting captured light into an electric signal, and a camera signal processing unit that performs signal processing such as analog-digital conversion of the captured image signal. 20 and an image processing unit 30 that performs recording / reproduction processing of an image signal. Further, the image pickup device 100 includes a display unit 40 for displaying a captured image and the like, an R / W (reader / writer) 50 for writing and reading an image signal to the memory 90, and the entire image pickup device 100. A CPU (Central Processing Unit) 60 to control, an input unit 70 such as various switches for which a user performs a required operation, and a lens for controlling the drive of an image pickup lens 1 (including an image pickup lens 2 to an image pickup lens 10). It includes a drive control unit 80.

The camera signal processing unit 20 performs various signal processing such as conversion of the output signal from the image pickup element 15 into a digital signal, noise removal, image quality correction, and conversion into a brightness / color difference signal.

The image processing unit 30 performs compression coding / decompression decoding processing of an image signal based on a predetermined image data format, conversion processing of data specifications such as resolution, and the like.

The display unit 40 has a function of displaying various data such as an operation state of the user's input unit 70 and a captured image.

The R / W 50 writes the image data encoded by the image processing unit 30 to the memory 90 and reads the image data recorded in the memory 90.

The CPU 60 functions as a control processing unit that controls each circuit block provided in the image pickup apparatus 100, and controls each circuit block based on an instruction input signal or the like from the input unit 70.

The input unit 70 outputs an instruction input signal according to the operation by the user to the CPU 60.

The lens drive control unit 80 controls a motor or the like (not shown) that drives a lens group based on a control signal from the CPU 60.

The memory 90 is, for example, a semiconductor memory that can be attached to and detached from the slot connected to the R / W 50. The memory 90 is not detachable from the slot and may be incorporated inside the image pickup apparatus 100.

The operation of the image pickup apparatus 100 will be described below.

In the shooting standby state, under the control of the CPU 60, the shot image signal is output to the display unit 40 via the camera signal processing unit 20 and displayed as a camera-through image.

When shooting is performed by the instruction input signal from the input unit 70, the shot image signal is output from the camera signal processing unit 20 to the image processing unit 30, compressed and encoded, and converted into digital data in a predetermined data format. Will be done. The converted data is output to the R / W 50 and written to the memory 90.

Focusing is performed by the lens drive control unit 80 moving the focus lens group based on the control signal from the CPU 60.

When the image data recorded in the memory 90 is reproduced, the R / W 50 reads out the predetermined image data from the memory 90 in response to the operation on the input unit 70, and the image processing unit 30 performs the decompression / decoding process. After that, the reproduced image signal is output to the display unit 40 and the reproduced image is displayed.

In the present technology, "imaging" means converting the photoelectric conversion process of converting the light captured by the image pickup element 15 into an electric signal to the digital signal of the output signal from the image pickup element 15 by the camera signal processing unit 20. , Noise removal, image quality correction, conversion to brightness / color difference signals, etc., compression coding / decompression decoding processing of image signals based on a predetermined image data format by the image processing unit 30, and conversion processing of data specifications such as resolution. , A process including only a part or all of a series of processes up to the process of writing an image signal to the memory 90 by the R / W 50.

That is, "imaging" may refer only to the photoelectric conversion process for converting the light captured by the imaging element 15 into an electric signal, and from the photoelectric conversion process for converting the light captured by the imaging element 15 into an electric signal. It may also refer to processing such as conversion of the output signal from the image pickup element 15 by the camera signal processing unit 20 into a digital signal, noise removal, image quality correction, and conversion into a brightness / color difference signal, and is captured by the image pickup element 15. After the photoelectric conversion process for converting light into an electric signal, the camera signal processing unit 20 converts the output signal from the image pickup element 15 into a digital signal, noise removal, image quality correction, conversion into a brightness / color difference signal, and the like. It may also refer to compression coding / decompression decoding processing of an image signal based on a predetermined image data format by the image processing unit 30 and conversion processing of data specifications such as resolution, and the light captured by the image pickup element 15 is an electric signal. The photoelectric conversion process of converting to It may be pointed out through compression coding / decompression decoding processing of an image signal based on a predetermined image data format, conversion processing of data specifications such as resolution, and writing processing of an image signal to the memory 90 by the R / W 50. You may point. In the above processing, the order of each processing may be changed as appropriate.

Further, in the present technology, the image pickup device 100 may be configured to include only a part or all of the image pickup element 15, the camera signal processing section 20, the image processing section 30, and the R / W 50 that perform the above processing. ..

[others]
In the present technology imaging lens and the present technology imaging device, in addition to the first lens group G1 and the second lens group G2, other optical elements such as a lens having no refractive power may be arranged. In this case, the lens configuration of the imaging lens of the present technology is substantially two groups of the first lens group G1 and the second lens group G2.

Although an example in which the image pickup device is applied to a digital still camera is shown above, the scope of application of the image pickup device is not limited to the digital still camera, and a digital video camera, a mobile phone having a built-in camera, etc. It can be widely applied as a camera unit of a digital input / output device in a mobile terminal.

[Technology]
The present technology can also have the following configurations.

<1>
It consists of a first lens group, an aperture diaphragm, and a second lens group arranged in order from the object side to the image side.
The first lens group includes a first negative meniscus lens having an aspherical shape on both sides or one side and having a convex surface facing the object side, and a second lens having a convex surface facing the object side, in order from the object side to the image side. It has a negative meniscus lens and a single lens having a negative refractive power or a unit in which negative and positive are arranged in order from the object side to the image side.
The second lens group has a positive lens group that moves from the image side to the object side when focusing from an infinite object to a short-distance object.
An imaging lens that satisfies the following conditional expression (1) and conditional expression (2).
(1) 40.00 <νdL1 <96.00
(2) -10.0 <fL1 / f <-2.0
However,
νdL1: Abbe number of the d line of the first negative meniscus lens fL1: Focal length of the first negative meniscus lens f: Focal length of the entire system at infinity focusing.

<2>
The imaging lens according to <1>, which satisfies the following conditional expression (5).
(5) 1.5 <fG2F / f <8.5
However,
fG2F: Focal length of the positive lens group in the second lens group f: Focal length of the entire system at infinity focusing.

<3>
The imaging lens according to <1> or <2>, which satisfies the following conditional expression (6).
(6) 3 <| fG1 / fG2 |
However,
fG1: Focal length of the first lens group fG2: Focal length of the second lens group.

<4>
The imaging lens according to any one of <1> to <3>, which satisfies the following conditional expression (7).
(7) 0.30 <fL1 / fL2 <2.50
However,
fL1: Focal length of the first negative meniscus lens fL2: Focal length of the second negative meniscus lens.

<5>
The imaging lens according to any one of <1> to <4>, which satisfies the following conditional expression (8).
(8) -1.5 <fG2 / fLA <-0.2
However,
fG2: Focal length of the second lens group fLA: Focal length of the negative air lens having the strongest refractive power in the second lens group.

<6>
The distance from the image plane side of the lens closest to the image plane to the image plane in the second lens group is set as the back focus.
The imaging lens according to any one of <1> to <5>, which satisfies the following conditional expression (9).
(9) 0.3 <BF / f <2.5
However,
BF: The back focus f: The focal length of the entire system when focusing at infinity.

<7>
The imaging lens according to any one of <1> to <6>, which satisfies the following conditional expression (10).
(10) 2.3 <SL1 <4.6
However,
SL1: Specific gravity of the first negative meniscus lens [g / square centimeter]
And.

<8>
The imaging lens according to any one of <1> to <7>, wherein the first lens group is fixed when focusing from an infinity object to a short-distance object.

<9>
It includes an image pickup lens and an image pickup element that converts an optical image formed by the image pickup lens into an electrical signal.
The image pickup lens is
It consists of a first lens group, an aperture diaphragm, and a second lens group arranged in order from the object side to the image side.
The first lens group includes a first negative meniscus lens having an aspherical shape on both sides or one side and having a convex surface facing the object side, and a second lens having a convex surface facing the object side, in order from the object side to the image side. It has a negative meniscus lens and a single lens having a negative refractive power or a unit in which negative and positive are arranged in order from the object side to the image side.
The second lens group has a positive lens group that moves from the image side to the object side when focusing from an infinite object to a short-distance object.
An imaging device that satisfies the following conditional expression (1) and conditional expression (2).
(1) 40.00 <νdL1 <96.00
(2) -10.0 <fL1 / f <-2.0
However,
νdL1: Abbe number of the d line of the first negative meniscus lens fL1: Focal length of the first negative meniscus lens f: Focal length of the entire system at infinity focusing.

<10>
It consists of a first lens group, an aperture diaphragm, and a second lens group arranged in order from the object side to the image side.
The first lens group includes a first negative meniscus lens having a convex surface facing the object side and a second negative meniscus lens having a convex surface facing the object side in order from the object side to the image side.
The first lens group is composed of a positive lens having an aspherical shape on both sides or one side, and a lens having a negative refractive power closest to the object side of the positive lens to a lens closest to the object side of the positive lens. Has a lens unit that is
The second lens group has a positive lens group that moves from the image side to the object side when focusing from an infinite object to a short-distance object.
An imaging lens that satisfies the following conditional expression (3) and conditional expression (4).
(3) -35.00 <fLN / fLP <-1.05
(4) 1.00 <dLP / dS <1.55
However,
fLN: Focal length of the lens unit fLP: Focal length of the positive lens in the first lens group dLP: Distance from the object-side surface to the image surface of the positive lens in the first lens group dS: From the aperture aperture The distance to the image plane.

<11>
The imaging lens according to <10>, which satisfies the following conditional expression (5).
(5) 1.5 <fG2F / f <8.5
However,
fG2F: Focal length of the positive lens group in the second lens group f: Focal length of the entire system at infinity focusing.

<12>
The imaging lens according to <10> or <11>, which satisfies the following conditional expression (6).
(6) 3 <| fG1 / fG2 |
However,
fG1: Focal length of the first lens group fG2: Focal length of the second lens group.

<13>
The imaging lens according to any one of <10> to <12>, which satisfies the following conditional expression (7).
(7) 0.30 <fL1 / fL2 <2.50
However,
fL1: Focal length of the first negative meniscus lens fL2: Focal length of the second negative meniscus lens.

<14>
The imaging lens according to any one of <10> to <13>, which satisfies the following conditional expression (8).
(8) -1.5 <fG2 / fLA <-0.2
However,
fG2: Focal length of the second lens group fLA: Focal length of the negative air lens having the strongest refractive power in the second lens group.

<15>
The distance from the image plane side of the lens closest to the image plane to the image plane in the second lens group is set as the back focus.
The imaging lens according to any one of <10> to <14>, which satisfies the following conditional expression (9).
(9) 0.3 <BF / f <2.5
However,
BF: The back focus f: The focal length of the entire system when focusing at infinity.

<16>
The imaging lens according to any one of <10> to <15>, which satisfies the following conditional expression (10).
(10) 2.3 <SL1 <4.6
However,
SL1: Specific gravity of the first negative meniscus lens [g / square centimeter]
And.

<17>
The imaging lens according to any one of <10> to <16>, wherein the first lens group is fixed when focusing from an infinity object to a short-distance object.

<18>
It includes an image pickup lens and an image pickup element that converts an optical image formed by the image pickup lens into an electrical signal.
The image pickup lens is
It consists of a first lens group, an aperture diaphragm, and a second lens group arranged in order from the object side to the image side.
The first lens group includes a first negative meniscus lens having a convex surface facing the object side and a second negative meniscus lens having a convex surface facing the object side in order from the object side to the image side.
The first lens group is composed of a positive lens having an aspherical shape on both sides or one side, and a lens having a negative refractive power closest to the object side of the positive lens to a lens closest to the object side of the positive lens. Has a lens unit that is
The second lens group has a positive lens group that moves from the image side to the object side when focusing from an infinite object to a short-distance object.
An imaging device that satisfies the following conditional expression (3) and conditional expression (4).
(3) -35.00 <fLN / fLP <-1.05
(4) 1.00 <dLP / dS <1.55
However,
fLN: Focal length of the lens unit fLP: Focal length of the positive lens in the first lens group dLP: Distance from the object-side surface to the image surface of the positive lens in the first lens group dS: From the aperture aperture The distance to the image plane.

1 to 10 Imaging Lens 100 Imaging Device G1 First Lens Group G2 Second Lens Group L1 First Negative Meniscus Lens L2 Second Negative Meniscus Lens L3 Lens LN Lens Unit LP Positive Lens G2F Positive Lens Group S Aperture Aperture

Claims

It consists of a first lens group, an aperture diaphragm, and a second lens group arranged in order from the object side to the image side.
The first lens group includes a first negative meniscus lens having an aspherical shape on both sides or one side and having a convex surface facing the object side, and a second lens having a convex surface facing the object side, in order from the object side to the image side. It has a negative meniscus lens and a single lens having a negative refractive power or a unit in which negative and positive are arranged in order from the object side to the image side.
The second lens group has a positive lens group that moves from the image side to the object side when focusing from an infinite object to a short-distance object.
An imaging lens that satisfies the following conditional expression (1) and conditional expression (2).
(1) 40.00 <νdL1 <96.00
(2) -10.0 <fL1 / f <-2.0
However,
νdL1: Abbe number of the d line of the first negative meniscus lens fL1: Focal length of the first negative meniscus lens f: Focal length of the entire system at infinity focusing.
The imaging lens according to claim 1, which satisfies the following conditional expression (5).
(5) 1.5 <fG2F / f <8.5
However,
fG2F: Focal length of the positive lens group in the second lens group f: Focal length of the entire system at infinity focusing.
The imaging lens according to claim 1, which satisfies the following conditional expression (6).
(6) 3 <| fG1 / fG2 |
However,
fG1: Focal length of the first lens group fG2: Focal length of the second lens group.
The imaging lens according to claim 1, which satisfies the following conditional expression (7).
(7) 0.30 <fL1 / fL2 <2.50
However,
fL1: Focal length of the first negative meniscus lens fL2: Focal length of the second negative meniscus lens.
The imaging lens according to claim 1, which satisfies the following conditional expression (8).
(8) -1.5 <fG2 / fLA <-0.2
However,
fG2: Focal length of the second lens group fLA: Focal length of the negative air lens having the strongest refractive power in the second lens group.
The distance from the image plane side of the lens closest to the image plane to the image plane in the second lens group is set as the back focus.
The imaging lens according to claim 1, which satisfies the following conditional expression (9).
(9) 0.3 <BF / f <2.5
However,
BF: The back focus f: The focal length of the entire system when focusing at infinity.
The imaging lens according to claim 1, which satisfies the following conditional expression (10).
(10) 2.3 <SL1 <4.6
However,
SL1: Specific gravity of the first negative meniscus lens [g / square centimeter]
And.
The imaging lens according to claim 1, wherein the first lens group is fixed when focusing from an infinity object to a short-distance object.
It includes an image pickup lens and an image pickup element that converts an optical image formed by the image pickup lens into an electrical signal.
The image pickup lens is
It consists of a first lens group, an aperture diaphragm, and a second lens group arranged in order from the object side to the image side.
The first lens group includes a first negative meniscus lens having an aspherical shape on both sides or one side and having a convex surface facing the object side, and a second lens having a convex surface facing the object side, in order from the object side to the image side. It has a negative meniscus lens and a single lens having a negative refractive power or a unit in which negative and positive are arranged in order from the object side to the image side.
The second lens group has a positive lens group that moves from the image side to the object side when focusing from an infinite object to a short-distance object.
An imaging device that satisfies the following conditional expression (1) and conditional expression (2).
(1) 40.00 <νdL1 <96.00
(2) -10.0 <fL1 / f <-2.0
However,
νdL1: Abbe number of the d line of the first negative meniscus lens fL1: Focal length of the first negative meniscus lens f: Focal length of the entire system at infinity focusing.
It consists of a first lens group, an aperture diaphragm, and a second lens group arranged in order from the object side to the image side.
The first lens group includes a first negative meniscus lens having a convex surface facing the object side and a second negative meniscus lens having a convex surface facing the object side in order from the object side to the image side.
The first lens group is composed of a positive lens having an aspherical shape on both sides or one side, and a lens having a negative refractive power closest to the object side of the positive lens to a lens closest to the object side of the positive lens. Has a lens unit that is
The second lens group has a positive lens group that moves from the image side to the object side when focusing from an infinite object to a short-distance object.
An imaging lens that satisfies the following conditional expression (3) and conditional expression (4).
(3) -35.00 <fLN / fLP <-1.05
(4) 1.00 <dLP / dS <1.55
However,
fLN: Focal length of the lens unit fLP: Focal length of the positive lens in the first lens group dLP: Distance from the object-side surface to the image surface of the positive lens in the first lens group dS: From the aperture aperture The distance to the image plane.
The imaging lens according to claim 10, which satisfies the following conditional expression (5).
(5) 1.5 <fG2F / f <8.5
However,
fG2F: Focal length of the positive lens group in the second lens group f: Focal length of the entire system at infinity focusing.
The imaging lens according to claim 10, which satisfies the following conditional expression (6).
(6) 3 <| fG1 / fG2 |
However,
fG1: Focal length of the first lens group fG2: Focal length of the second lens group.
The imaging lens according to claim 10, which satisfies the following conditional expression (7).
(7) 0.30 <fL1 / fL2 <2.50
However,
fL1: Focal length of the first negative meniscus lens fL2: Focal length of the second negative meniscus lens.
The imaging lens according to claim 10, which satisfies the following conditional expression (8).
(8) -1.5 <fG2 / fLA <-0.2
However,
fG2: Focal length of the second lens group fLA: Focal length of the negative air lens having the strongest refractive power in the second lens group.
The distance from the image plane side of the lens closest to the image plane to the image plane in the second lens group is set as the back focus.
The imaging lens according to claim 10, which satisfies the following conditional expression (9).
(9) 0.3 <BF / f <2.5
However,
BF: The back focus f: The focal length of the entire system when focusing at infinity.
The imaging lens according to claim 10, which satisfies the following conditional expression (10).
(10) 2.3 <SL1 <4.6
However,
SL1: Specific gravity of the first negative meniscus lens [g / square centimeter]
And.
The imaging lens according to claim 10, wherein the first lens group is fixed when focusing from an infinity object to a short-distance object.
It includes an image pickup lens and an image pickup element that converts an optical image formed by the image pickup lens into an electrical signal.
The image pickup lens is
It consists of a first lens group, an aperture diaphragm, and a second lens group arranged in order from the object side to the image side.
The first lens group includes a first negative meniscus lens having a convex surface facing the object side and a second negative meniscus lens having a convex surface facing the object side in order from the object side to the image side.
The first lens group is composed of a positive lens having an aspherical shape on both sides or one side, and a lens having a negative refractive power closest to the object side of the positive lens to a lens closest to the object side of the positive lens. Has a lens unit that is
The second lens group has a positive lens group that moves from the image side to the object side when focusing from an infinite object to a short-distance object.
An imaging device that satisfies the following conditional expression (3) and conditional expression (4).
(3) -35.00 <fLN / fLP <-1.05
(4) 1.00 <dLP / dS <1.55
However,
fLN: Focal length of the lens unit fLP: Focal length of the positive lens in the first lens group dLP: Distance from the object-side surface to the image surface of the positive lens in the first lens group dS: From the aperture aperture The distance to the image plane.