JP6126431B2 - Optical system and imaging apparatus having the same - Google Patents

Description

  The present invention relates to a lens apparatus and an imaging apparatus having the same, and more particularly to a single-focus lens apparatus suitable for a surveillance camera, a vehicle-mounted camera, a video camera, a digital still camera, and the like and an imaging apparatus having the same.

  Conventionally, a single-focus wide-angle lens having high optical performance corresponding to an increase in the number of pixels of an image pickup device has been proposed for an image pickup apparatus such as a monitoring camera or a vehicle-mounted camera. For example, in Patent Documents 1, 2, and 3, a retrofocus single-focus wide-angle lens including a negative or positive first lens group, a stop, and a positive second lens group is known.

Japanese Patent No. 4186560 Japanese Patent No. 5045300 JP 2012-18422 A

  In recent years, there has been a demand for a single-focus lens with a wide angle of view in imaging apparatuses such as surveillance cameras and in-vehicle cameras.

  However, as in Patent Documents 1, 2, and 3, the peripheral portion of an image using a lens that achieves a wide angle of view by intentionally leaving negative distortion more than about -80% is distorted at the periphery. It becomes unnatural.

  With the development of image processing technology, an image pickup apparatus that electronically corrects distortion and suppresses image distortion has been proposed. However, since the compressed image is electronically stretched, the resolution is deteriorated at the peripheral angle of view.

  Further, in order to design with a wide angle of view and suppressing negative distortion, it is necessary to shorten the focal length. However, since the refractive power of each lens becomes strong, it is difficult to correct various aberrations.

In an optical system including a first lens group , an aperture stop , and a second lens group having a positive refractive power , which are arranged in order from the object side to the image side, the first lens group is arranged in order from the object side . , a negative meniscus lens having a convex surface directed toward the object side, a negative meniscus lens having a convex surface on the object side, and a positive lens, the second lens group, a negative lens and at least two positive lenses has a focal length of the entire system f, the focal length of the first lens group f1, .nu.1p the Abbe number of the material of the positive lens in the focal length of the second lens group f2, the first lens group The average value of the Abbe number of the negative lens material included in the first lens group is ν1n, the average value of the Abbe number of the material of the positive lens included in the second lens group is ν2p , and is included in the second lens group. Abbe number of the negative lens of the materials When the average value and Nyu2n, and satisfies the following conditional expression.
−0.25 <f / f1 <0.20
0.33 <f / f2 <0.60
0.20 <ν1p / ν1n <0.70
3.00 <ν2p / ν2n <6.00

  The present invention provides a single-focus lens device having a wide field angle, low distortion, and high optical performance corresponding to a high-definition imaging device, and an imaging device having the same.

Lens sectional view of Numerical Example 1 Aberration diagram at the object distance of 1 m in Numerical Example 1. Lens sectional view of Numerical Example 2 Aberration diagram at the object distance of 1 m in Numerical Example 2. Lens sectional view of Numerical Example 3 Aberration diagram at object distance 1 m in Numerical Example 3 Lens sectional view of Numerical Example 4 Aberration diagram at object distance 1 m in Numerical Example 4 Lens sectional view of Numerical Example 5 Aberration diagram at object distance 1 m in Numerical Example 5 Schematic diagram of main parts of an imaging apparatus of the present invention

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a lens cross-sectional view of a lens apparatus of Example 1 (Numerical Example 1) of the present invention. In FIG. 1, the lens apparatus according to the first exemplary embodiment includes, in order from the object side, a first lens group G1, an aperture stop SP, and a second lens group G2 having a positive refractive power. FL shown in FIG. 1 is a parallel plate corresponding to a low-pass filter, an IR cut filter, or the like. Reference numeral I denotes an imaging surface, which corresponds to an imaging surface such as a solid-state imaging device (photoelectric conversion device) that receives subject light from the imaging lens and performs photoelectric conversion. The above configuration is exactly the same in each embodiment.

  FIG. 2 is an aberration diagram of the numerical example 1 at an object distance of 1 m, and the unit is mm (distortion only%). In the longitudinal aberration diagram, spherical aberration indicates d-line (solid line) and g-line (two-dot chain line). Astigmatism indicates the sagittal image plane (solid line) and the meridional image plane (dotted line) of the d line. The lateral chromatic aberration represents the g-line (two-dot chain line). Fno represents an F number, and ω represents a shooting half angle of view. In the longitudinal aberration diagram, the spherical aberration is drawn on a scale of 0.1 mm, the astigmatism is 0.1 mm, the distortion is 10%, and the lateral chromatic aberration is drawn on a scale of 0.02 mm. In the lateral aberration diagram, sagittal ray aberration (solid line) and meridional ray aberration (dotted line) of d line are shown, and drawn on a scale of 0.02 mm. The notation and scale of the aberration diagrams are the same in the following examples.

The lens apparatus in each embodiment of the present invention includes, in order from the object side, a first lens group, an aperture stop, and a second lens group having a positive refractive power. The first lens group includes, in order from the object side, a first negative lens, a second negative lens, and a positive lens. The second lens group has at least one negative lens and at least two positive lenses. Each negative lens in the first lens group is a meniscus lens having a convex surface facing the object side. At least one surface of the second negative lens of the first lens group has an aspheric surface. The focal length of the entire system is f, the focal lengths of the first lens group and the second lens group are f1 and f2, respectively, and the average values of the Abbe numbers of the positive lens and negative lens of the first lens group are ν1p and ν1n, respectively. When the average values of Abbe numbers of the positive lens and negative lens in the lens group are ν2p and ν2n, respectively.
-0.25 <f / f1 <0.20 (1)
0.33 <f / f2 <0.60 (2)
0.20 <ν1p / ν1n <0.70 (3)
3.00 <ν2p / ν2n <6.00 (4)
It is characterized by satisfying the following conditions.

  The lens apparatus in each embodiment has a retrofocus configuration suitable for achieving a wide angle of view sufficient for monitoring applications, and the first lens group includes a first negative lens, a second negative lens, and a positive lens. It is preferable to use three sheets. Further, it is preferable that the second lens group as the imaging lens group includes at least two positive lenses and at least one negative lens for correcting chromatic aberration.

According to the aberration theory, the distortion aberration is proportional to the height h of the paraxial axial ray from the optical axis and proportional to the cube of the height hbar of the paraxial off-axis principal ray from the optical axis. Since the lens apparatus according to the present invention has a wide angle of view and off-axis incident light rays from the object have a large incident angle, negative lenses generated in the first negative lens and the second negative lens having the largest hbar far from the stop. It is important to suppress distortion. Therefore, it is preferable that the first negative lens and the second negative lens are meniscus lenses each having a convex surface facing the object side and having a shape that suppresses the refraction angle of off-axis rays on each surface.

Further, field curvature and astigmatism are proportional to the square of the height h of the paraxial light beam from the optical axis, and proportional to the square of the height hbar of the paraxial off-axis principal ray from the optical axis. . In the lens apparatus of the present invention, in order to effectively correct curvature of field and astigmatism in addition to suppressing negative distortion, hbar is not too small, and h is a second negative larger than the first negative lens. It is preferable to apply an aspherical surface to the lens.
Furthermore, in each embodiment, in order to more effectively correct curvature of field and astigmatism, it is more preferable that both surfaces of the second negative lens are aspherical surfaces.

  Conditional expression (1) defines the ratio between the focal length f of the entire system and the focal length f1 of the first lens group. Similarly, conditional expression (2) defines the ratio between the focal length f of the entire system and the focal length f2 of the second lens group. When the upper limit of conditional expression (1) is exceeded, the convergence of the light beam incident on the second lens group becomes too large, making it difficult to achieve sufficient back focus. If the lower limit of conditional expression (1) is exceeded, the divergence of the light beam incident on the second lens group becomes too large, making it difficult to correct various aberrations.

If the upper limit of conditional expression (2) is exceeded, the refractive power of the second lens group becomes too strong, making it difficult to correct various aberrations. If the lower limit of conditional expression (2) is exceeded, the refractive power becomes too weak, making it difficult to obtain a wide angle of view that is sufficient for monitoring purposes. More preferably, conditional expressions (1) and (2) are set as follows.
-0.19 <f / f1 <0.12 (1a)
0.35 <f / f2 <0.47 (2a)

Conditional expression (3) defines the ratio of the average values ν1p and ν1n of the Abbe numbers of the positive lens and the negative lens in the first lens group. Similarly, the conditional expression (4) defines the ratio between the average values ν2p and ν2n of the Abbe numbers of the positive lens and the negative lens in the second lens group. Since the lens apparatus according to the present invention corrects negative distortion well, it is necessary to reduce the focal length in order to widen the angle of view. For this reason, the refractive power of the second lens group, which plays a major role as an imaging lens group, increases, and accordingly, the refractive power of each lens in the second lens group also increases, so that the amount of various aberrations tends to increase. In order to reduce the individual lens refractive power in the second lens group having a positive refractive power, the first-order achromatic conditional expression φp / νp + φn / νn = 0 in the lens group.
(Φp and φn are the refractive powers of the positive lens and negative lens, νp and νn are positive lenses,
Abbe number of negative lens)
Therefore, it is preferable that the Abbe number ratio νp / νn of the positive lens and the negative lens be as large as possible.

  On the other hand, if the Abbe number ratio in the second lens group is increased, the axial chromatic aberration in the second lens group is overcorrected, and therefore the Abbe number ratio in the first lens group is overcorrected. It is preferable that the range is appropriately balanced.

If the upper limit of conditional expression (3) is exceeded, axial chromatic aberration will be overcorrected, and it will be difficult to achieve both lateral chromatic aberration correction. If the lower limit of conditional expression (3) is exceeded, the longitudinal chromatic aberration will be insufficiently corrected, or it will be difficult to achieve both lateral chromatic aberration correction. If the upper limit of conditional expression (4) is exceeded, axial chromatic aberration will be overcorrected. If the lower limit of conditional expression (4) is exceeded, the individual lens refractive power in the second lens group becomes too large, and various aberrations increase, making it difficult to obtain high optical performance. More preferably, conditional expressions (3) and (4) should be set as follows.
0.28 <ν1p / ν1n <0.57 (3a)
3.20 <ν2p / ν2n <4.80 (4a)

The lens apparatus in each embodiment of the present invention, when the half field angle of the incident light at the maximum image height Y is ω,
0.7 <Y / {f × tan (ω)} <1.0 (5)
It is characterized by satisfying the following conditions.

The calculation formula of imaginary height is
Y = f × tan (ω)
The image height and the tangent of the angle of view are proportional to each other, but nonlinearity occurs due to the influence of distortion. Since the lens apparatus of the present invention suppresses negative distortion as small as about −10%, conditional expression (5) takes a value close to 1.0, which means a proportional relationship.

When the upper limit of conditional expression (5) is exceeded, correction of off-axis aberrations such as halo and coma becomes difficult, and high optical performance cannot be achieved. If the lower limit of conditional expression (5) is exceeded, sufficient distortion suppression cannot be achieved.
More preferably, conditional expression (5) should be set as follows.
0.85 <Y / {f × tan (ω)} <0.95 (5a)

By the way, in an imaging apparatus such as a surveillance camera or an in-vehicle camera, there is a demand for a pan focus lens that does not have a focusing mechanism for high reliability, simplification of the mechanism, reduction in size and weight, cost reduction, and the like. The pan focus lens is within the depth of field range from infinity to the closest distance, and the closest distance is ε as the permissible circle of confusion.
sh = f ² / (ε × Fno)
It becomes half sh / 2 of the hyperfocal distance sh defined by. Therefore, it is preferable that the hyperfocal distance sh is small in order to perform in-focus shooting in a wider distance range. However, in a lens that achieves a wide angle of view due to a large negative distortion, the focal length becomes relatively long even at the same angle of view, so that the hyperfocal distance becomes long and the operation as a pan focus lens becomes difficult. . Furthermore, in surveillance applications, it is important to use a bright lens with a small F-number when shooting in a dark place. . As described above, in order to operate as a pan focus lens in a monitoring application or the like, it is necessary to appropriately set the focal length and the F number. In response to these problems, the lens device of the present invention has an F number at the infinity state of Fno,
0.50 <f ² /(Y×Fno)<2.50 (unit mm) (6)
It is characterized by satisfying the following conditions.

In the above-described hyperfocal distance sh, ε is proportional to the pixel pitch p in the diagonal direction of the image sensor I, and therefore has a relationship of ε∝p. Further, since the pixel pitch p is the number of pixels n in the diagonal direction of the image sensor and the maximum image height Y and can be expressed as p = 2 × Y / n, the hyperfocal distance sh is expressed as f ² / (Y × Fno). Can be replaced. That is, conditional expression (6) defines the hyperfocal distance, that is, the closest distance. If the upper limit of conditional expression (6) is exceeded, the closest distance will be long and operation as a pan focus lens will be difficult, or it will be difficult to obtain a sufficient angle of view for monitoring purposes. On the other hand, if the lower limit of conditional expression (6) is exceeded, it will be difficult to maintain sufficient brightness for monitoring applications, etc., or the refractive power of the lens will increase, making it difficult to achieve low distortion and improve performance. It becomes. More preferably, conditional expression (6) should be set as follows.
0.70 <f ² /(Y×Fno)<2.10 (unit mm) (6a)

The lens apparatus in each embodiment of the present invention preferably satisfies the following conditional expression when the refractive index at the d-line of the positive lens of the first lens group is n1p.
1.90 <n1p <2.30 (7)

By suppressing the occurrence of negative distortion in the first negative lens and the second negative lens, and generating positive distortion in the positive lens of the first lens group, it is possible to more effectively reduce the negative distortion. Yes. In order to generate a positive distortion, it is necessary to refract off-axis rays greatly, which causes higher-order halo and coma aberration in the peripheral image height. In order to suppress the occurrence of these higher-order aberrations, it is effective to increase the refractive index n1p and weaken the refractive power of the positive lens. If the upper limit of conditional expression (7) is exceeded, the Abbe number will be too small with existing lens materials, and axial chromatic aberration will be insufficiently corrected, or it will be difficult to achieve both lateral chromatic aberration correction. If the lower limit of conditional expression (7) is exceeded, the refractive power of the positive lens will increase, and higher-order halo and coma will increase, making it difficult to achieve good optical performance. More preferably, conditional expression (7) should be set as follows.
1.90 <n1p <2.15 (7a)

In the lens apparatus according to each embodiment of the present invention, the second lens group includes a cemented lens of a negative lens and a positive lens, and when the Abbe numbers of the negative lens and the positive lens of the cemented lens are νcn and νcp, Is preferably satisfied.
3.00 <νcp / νcn <6.00 (8)

By arranging the cemented lens in the second lens group, chromatic aberration can be corrected more effectively. For the same reason as described in the conditional expression (4), by increasing the Abbe number ratio between the negative lens and the positive lens of the cemented lens that greatly contributes to chromatic aberration, it is possible to effectively refract the individual lenses in the second lens group. The power can be reduced. If the upper limit of conditional expression (8) is exceeded, the axial chromatic aberration will be overcorrected. If the lower limit of conditional expression (8) is exceeded, the refractive power of each lens in the second lens group becomes too large, and various aberrations increase, making it difficult to obtain high optical performance. More preferably, conditional expression (8) should be set as follows.
3.70 <νcp / νcn <5.50 (8a)

In the lens apparatus according to each embodiment of the present invention, the second lens group includes a cemented lens of a negative lens and a positive lens, and when the refractive indexes of the negative lens and the positive lens of the cemented lens are ncn and ncp, the following conditional expression Is preferably satisfied.
0.30 <ncn−ncp <0.60 (9)

The cemented lens has a configuration that effectively corrects chromatic aberration, but by increasing the refractive index difference between the positive lens and the negative lens constituting the cemented lens in the second lens group, the reference wavelength (d line) on the cemented surface is increased. ) Can be increased to correct not only chromatic aberration but also spherical aberration and coma aberration. When the upper limit of conditional expression (9) is exceeded, with existing lens materials, the Abbe number ratio in the cemented lens becomes too large, and the axial chromatic aberration is overcorrected. If the lower limit of conditional expression (9) is exceeded, the refractive power of the cemented surface becomes too small, and various aberrations increase, making it difficult to obtain high optical performance. More preferably, conditional expression (9) should be set as follows.
0.36 <ncn-ncp <0.55 (9a)

  It is preferable that the lens apparatus in each embodiment of the present invention has the following lens configuration (A) or (B).

(A) The second lens group includes, in order from the object side, a cemented lens including a negative lens and a positive lens, a positive lens, and a positive lens.
In an imaging apparatus having a solid-state imaging element, if the angle of light incident on the imaging element is too large, the amount of peripheral light is reduced and shading occurs. Therefore, the exit pupil of the lens needs to be substantially telecentric as far as possible from the imaging surface.
In order to realize this, it is effective to make the second lens group located behind the aperture stop a retrofocus type like the above lens configuration.

(B) The second lens group includes, in order from the object side, a cemented lens including a positive lens and a negative lens, and a positive lens, and the positive lens closest to the image side has an aspherical surface.
As another lens configuration, it is possible to achieve both wide angle and off-axis aberration correction in the same manner by setting the number of lenses of the second lens group to three and disposing an aspherical surface on the most positive lens on the image side.

  Next, the features of the lens configuration of each example will be described.

  A specific lens configuration according to the first embodiment of the present invention will be described below with reference to FIG.

  FIG. 1 is a lens cross-sectional view of a lens apparatus of Example 1 (Numerical Example 1) of the present invention. The lens apparatus according to the first exemplary embodiment includes, in order from the object side, a first lens group G1, an aperture stop SP, and a second lens group G2 having a positive refractive power. The first lens group G1 includes, in order from the object side, a negative meniscus lens L1 that is convex toward the object side, a negative meniscus lens L2 that is convex toward the object side and is a double-sided aspheric surface, and a positive lens L3. The second lens group G2 includes, in order from the object side, a cemented lens in which a negative lens L4 and a positive lens L5 are cemented, a positive lens L6, and a positive lens L7. FL is a parallel plate corresponding to a low-pass filter, an IR cut filter, or the like. Reference numeral I denotes an imaging surface, which corresponds to an imaging surface such as a solid-state imaging device (photoelectric conversion device) that receives subject light from a lens and performs photoelectric conversion.

  Table 1 shows the corresponding values of Example 1 for the conditional expressions (1) to (9). Numerical Example 1 satisfies all the conditional expressions, and realizes a lens apparatus having a small F number, a wide angle of view, low distortion, and high optical performance corresponding to a high-definition image sensor.

  FIG. 3 is a lens cross-sectional view of a lens apparatus according to Embodiment 2 (Numerical Embodiment 2) of the present invention. The lens configuration is exactly the same as in Example 1.

  Table 1 shows the corresponding values of Example 2 for the conditional expressions (1) to (9). Numerical Example 2 satisfies all the conditional expressions, and realizes a lens apparatus having a small F number, a wide field angle, low distortion, and high optical performance corresponding to a high-definition image sensor.

  FIG. 5 is a lens cross-sectional view of a lens apparatus according to Embodiment 3 (Numerical Embodiment 3) of the present invention. The lens configuration is exactly the same as in Example 1.

  Table 1 shows corresponding values of Example 3 for the conditional expressions (1) to (9). Numerical Example 3 satisfies all the conditional expressions, and realizes a lens apparatus having a small F number, a wide angle of view, low distortion, and high optical performance corresponding to a high-definition image sensor.

  FIG. 7 is a lens cross-sectional view of a lens apparatus according to Example 4 (Numerical Example 4) of the present invention. The lens apparatus according to the fourth exemplary embodiment includes, in order from the object side, a first lens group G1, an aperture stop SP, and a second lens group G2 having a positive refractive power. The first lens group G1 includes a negative meniscus lens L1 that is convex on the object side, a negative meniscus lens L2 that is convex on the object side and is aspheric on both sides, and a positive lens L3. The second lens group G2 includes, in order from the object side, a cemented lens in which a positive lens L4 and a negative lens L5 are cemented, and a double-sided aspheric positive lens L6. FL is a parallel plate corresponding to a low-pass filter, an IR cut filter, or the like. Reference numeral I denotes an imaging surface, which corresponds to an imaging surface such as a solid-state imaging device (photoelectric conversion device) that receives subject light from a lens and performs photoelectric conversion.

  Table 1 shows the corresponding values of Example 4 for the conditional expressions (1) to (9). Numerical Example 4 satisfies all the conditional expressions, and realizes a lens apparatus having a small F number, a wide angle of view, low distortion, and high optical performance corresponding to a high-definition image sensor.

  FIG. 9 is a lens cross-sectional view of a lens apparatus according to Example 5 (Numerical Example 5) of the present invention. The lens configuration is exactly the same as in Example 4.

  Table 1 shows the corresponding values of Example 5 for the conditional expressions (1) to (9). Numerical Example 5 satisfies all of the conditional expressions, and realizes a lens apparatus having a small F-number, a wide angle of view, low distortion, and high optical performance corresponding to a high-definition image sensor.

  FIG. 11 is a schematic diagram of a main part of an image pickup apparatus 110 that uses the lens apparatus of Embodiments 1 to 5 as a photographing optical system. In FIG. 11, reference numeral 101 denotes a lens device according to any one of Examples 1 to 5, reference numeral 102 denotes a first lens group, SP denotes an aperture stop, and 103 denotes a second lens group. Reference numeral 109 denotes an imaging unit including an imaging element and the like.

Reference numeral 108 denotes driving means such as a motor for electrically driving the focusing portion and the aperture stop SP. Reference numeral 107 denotes detection means such as an encoder, a potentiometer, or a photosensor for detecting the position of the in-focus portion on the optical axis and the aperture diameter of the aperture stop SP. Reference numeral 104 denotes a glass block corresponding to a low-pass filter, an IR cut filter, or the like in the camera 109. Reference numeral 105 denotes a solid-state image sensor (photoelectric conversion element) such as a CCD sensor or a CMOS sensor that receives a subject image formed by the lens device 101. . Reference numeral 106 denotes a CPU that controls various types of driving of the lens apparatus 101 and calculation of image processing.
Thus, by applying the lens apparatus of the present invention to an imaging camera or the like, an imaging apparatus having high optical performance is realized.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

  Numerical examples 1 to 5 for Examples 1 to 5 of the present invention are shown below. In each numerical example, the surface number indicates the order of the surfaces from the object side, r is the radius of curvature, d is the lens thickness or surface interval, nd and νd are the refractive index and Abbe number of the optical member, and the effective diameter is the ray. This is the maximum effective area that passes through. Aspherical surfaces are marked with * next to the surface number.

The aspherical shape is the X axis in the optical axis direction, the H axis in the direction perpendicular to the optical axis, the light traveling direction is positive, R is the paraxial radius of curvature, k is the cone constant, When each of them is an aspheric coefficient, it is expressed by Equation 1. “E-Z” means “× 10 ^−Z ”.

Numerical example 1
Unit mm

Surface data surface number rd nd vd Effective diameter
1 9.506 0.80 1.80 400 46.6 10.60
2 4.605 1.06 7.94
3 * 5.351 0.80 1.58313 59.4 7.71
4 * 2.411 5.32 6.00
5 44.521 1.72 2.00069 25.5 4.45
6 -11.719 2.47 4.02
7 (Aperture) ∞ 1.87 3.67
8 23.066 0.80 1.95906 17.5 3.59
9 5.578 3.43 1.55332 71.7 3.49
10 -8.933 0.15 5.40
11 20.695 1.63 1.49700 81.5 5.98
12 -30.189 0.09 6.43
13 9.814 1.89 1.77250 49.6 6.81
14 184.683 3.99 6.69
15 ∞ 0.50 1.51633 64.1 10.00
16 ∞ 0.50 10.00
Image plane ∞

Aspheric data 3rd surface
K = -1.04978e + 000 A 4 = 1.81276e-003 A 6 = -2.22766e-004 A 8 = 1.40361e-005 A10 = -5.52816e-007 A12 = 1.00402e-008

4th page
K = -9.51025e-001 A 4 = 5.11349e-003 A 6 = -4.40018e-004 A 8 = 3.54637e-005 A10 = -3.15904e-006 A12 = 1.08491e-007

Various data focal length 2.90
F number 1.85
Half angle of view 48.98
Statue height 3.00
Total lens length 26.86
BF 4.82

Entrance pupil position 4.94
Exit pupil position -36.27
Front principal point position 7.61
Rear principal point position -2.40

Lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 32.59 9.71 23.19 43.94
2 7 6.70 9.86 5.50 -1.28
3 15 ∞ 0.50 0.16 -0.16

Single lens Data lens Start surface Focal length
1 1 -11.98
2 3 -8.36
3 5 9.41
4 8 -7.85
5 9 6.78
6 11 24.97
7 13 13.35
8 15 0.00

Numerical example 2
Unit mm

Surface data surface number rd nd vd Effective diameter
1 10.866 0.80 1.72916 54.7 10.84
2 4.803 1.11 8.12
3 * 5.693 0.80 1.55332 71.7 7.89
4 * 2.442 5.21 6.15
5 35.650 1.87 1.90366 31.3 4.91
6 -10.719 2.79 4.49
7 (Aperture) ∞ 1.98 3.71
8 29.399 0.80 1.92286 18.9 3.60
9 5.765 2.82 1.55332 71.7 3.67
10 -9.831 0.15 5.18
11 24.395 1.69 1.51633 64.1 5.71
12 -22.065 0.10 6.23
13 9.534 1.91 1.77250 49.6 6.66
14 132.428 3.99 6.55
15 ∞ 0.50 1.51633 64.1 10.00
16 ∞ 0.50 10.00
Image plane ∞

Aspheric data 3rd surface
K = -9.49449e-001 A 4 = 1.49704e-003 A 6 = -1.99514e-004 A 8 = 1.10616e-005 A10 = -3.91278e-007 A12 = 6.43519e-009

4th page
K = -9.17463e-001 A 4 = 4.58466e-003 A 6 = -4.11385e-004 A 8 = 3.09367e-005 A10 = -2.81263e-006 A12 = 9.70174e-008

Various data focal length 3.00
F number 1.85
Half angle of view 48.01
Statue height 3.00
Total lens length 26.87
BF 4.82

Entrance pupil position 5.07
Exit pupil position -29.37
Front principal point position 7.77
Rear principal point position -2.50

Lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 27.64 9.80 20.25 36.47
2 7 6.82 9.45 5.30 -1.26
3 15 ∞ 0.50 0.16 -0.16

Single lens Data lens Start surface Focal length
1 1 -12.50
2 3 -8.47
3 5 9.30
4 8 -7.90
5 9 7.02
6 11 22.72
7 13 13.21
8 15 0.00

Numerical Example 3
Unit mm

Surface data surface number rd nd vd Effective diameter
1 9.748 0.80 1.77250 49.6 11.17
2 5.255 1.19 8.70
3 * 5.981 0.80 1.69350 53.2 8.43
4 * 2.585 5.11 6.48
5 28.630 1.70 2.00100 29.1 5.24
6 -13.722 2.80 4.84
7 (Aperture) ∞ 2.47 4.74
8 22.518 0.80 1.95906 17.5 4.65
9 6.223 2.66 1.49700 81.5 4.52
10 -9.380 0.10 5.91
11 28.102 1.53 1.49700 81.5 6.58
12 -23.071 0.05 7.06
13 8.429 2.14 1.77250 49.6 7.71
14 376.608 3.97 7.50
15 ∞ 0.50 1.51633 64.1 10.00
16 ∞ 0.50 10.00
Image plane ∞

Aspheric data 3rd surface
K = -1.32242e + 000 A 4 = 5.20488e-004 A 6 = -1.48931e-004 A 8 = 1.11905e-005 A10 = -4.18229e-007 A12 = 6.39074e-009

4th page
K = -9.99466e-001 A 4 = 3.58264e-003 A 6 = -4.74680e-004 A 8 = 4.62609e-005 A10 = -2.61091e-006 A12 = 5.95543e-008

Various data focal length 3.00
F number 1.44
Half angle of view 48.02
Statue height 3.00
Total lens length 26.96
BF 4.80

Entrance pupil position 5.28
Exit pupil position -48.59
Front principal point position 8.10
Rear principal point position -2.50

Lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 45.11 9.61 29.49 55.08
2 7 6.53 9.75 5.67 -1.30
3 15 ∞ 0.50 0.16 -0.16

Single lens Data lens Start surface Focal length
1 1 -16.00
2 3 -7.27
3 5 9.46
4 8 -9.19
5 9 7.98
6 11 25.75
7 13 11.13
8 15 0.00

Numerical Example 4
Unit mm

Surface data surface number rd nd vd Effective diameter
1 13.048 0.80 1.72916 54.7 13.50
2 5.418 2.52 9.58
3 * 6.750 0.80 1.55332 71.7 8.68
4 * 2.058 2.98 6.35
5 19.995 4.45 2.00069 25.5 5.88
6 -18.928 2.24 4.22
7 (Aperture) ∞ 1.51 2.82
8 12.487 2.34 1.55332 71.7 3.36
9 -3.752 0.80 1.92286 18.9 4.24
10 -8.215 0.10 4.99
11 * 29.915 2.89 1.58313 59.4 5.33
12 * -3.987 3.90 6.35
13 ∞ 0.50 1.51633 64.1 10.00
14 ∞ 0.50 10.00
Image plane ∞

Aspheric data 3rd surface
K = -1.94531e + 000 A 4 = -3.09257e-004 A 6 = -1.06411e-004 A 8 = 7.59464e-006 A10 = -2.37906e-007 A12 = 3.10972e-009

4th page
K = -9.58691e-001 A 4 = 2.22709e-004 A 6 = -3.93665e-004 A 8 = 1.76771e-005 A10 = -3.48121e-007 A12 = 1.37046e-008

11th page
K = -1.10719e + 002 A 4 = -2.05379e-003 A 6 = -8.73467e-005 A 8 = 1.10319e-006 A10 = -1.01202e-006 A12 = 6.39237e-009

12th page
K = -3.25120e + 000 A 4 = -3.44869e-003 A 6 = 4.42330e-005 A 8 = 3.41073e-006 A10 = -9.32801e-007 A12 = 1.92139e-008

Various data focal length 2.00
F number 1.85
Half angle of view 59.91
Statue height 3.00
Total lens length 26.14
BF 4.73

Entrance pupil position 5.17
Exit pupil position -100.03
Front principal point position 7.13
Rear principal point position -1.50

Lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 -16.62 11.54 -4.98 -23.87
2 7 5.11 7.63 4.85 -1.00
3 13 ∞ 0.50 0.16 -0.16

Single lens Data lens Start surface Focal length
1 1 -13.30
2 3 -5.70
3 5 10.31
4 8 5.50
5 9 -8.19
6 11 6.23
7 13 0.00

Numerical Example 5
Unit mm

Surface data surface number rd nd vd Effective diameter
1 12.783 0.80 1.77250 49.6 13.50
2 5.451 2.19 9.64
3 * 6.519 0.80 1.55332 71.7 9.00
4 * 2.139 4.69 6.57
5 18.835 3.22 1.95906 17.5 5.10
6 -44.018 1.89 3.80
7 (Aperture) ∞ 0.71 4.06
8 8.237 3.40 1.43875 94.9 4.19
9 -4.044 0.80 1.95906 17.5 4.37
10 -7.680 0.53 5.10
11 * 9.309 3.13 1.55332 71.7 6.19
12 * -4.944 3.90 6.37
13 ∞ 0.50 1.51633 64.1 10.00
14 ∞ 0.50 10.00
Image plane ∞

Aspheric data 3rd surface
K = -2.13664e + 000 A 4 = -1.03063e-004 A 6 = -1.07352e-004 A 8 = 7.73577e-006 A10 = -2.29290e-007 A12 = 2.97657e-009

4th page
K = -9.60291e-001 A 4 = 2.24345e-004 A 6 = -3.85137e-004 A 8 = 2.07413e-005 A10 = -4.35811e-007 A12 = 2.73398e-008

11th page
K = -2.31297e + 000 A 4 = -3.55059e-004 A 6 = 2.80314e-005 A 8 = 6.45316e-006 A10 = -1.04930e-007 A12 = 1.40978e-009

12th page
K = -4.62509e + 000 A 4 = -1.10781e-003 A 6 = 1.05266e-004 A 8 = 4.66334e-006 A10 = -4.58068e-007 A12 = 4.11357e-008

Various data focal length 2.00
F number 1.44
Half angle of view 59.91
Statue height 3.00
Total lens length 26.88
BF 4.73

Entrance pupil position 5.06
Exit pupil position -83.03
Front principal point 7.01
Rear principal point position -1.50

Lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 -10.81 11.70 -1.94 -17.96
2 7 5.60 8.56 5.22 -1.91
3 13 ∞ 0.50 0.16 -0.16

Single lens Data lens Start surface Focal length
1 1 -12.92
2 3 -6.15
3 5 14.11
4 8 6.75
5 9 -9.98
6 11 6.33
7 13 0.00

L1 first lens, L2 second lens, L3 third lens, L4 fourth lens, L5 fifth lens, L6 sixth lens, L7 seventh lens, G1 first lens group, G2 second lens group, SP aperture stop

Claims (9)

In an optical system including a first lens group , an aperture stop , and a second lens group having a positive refractive power , which are arranged in order from the object side to the image side ,
Wherein the first lens group, disposed in order from the object side, a negative meniscus lens having a convex surface facing the object side, a negative meniscus lens having a convex surface on the object side, and a positive lens,
The second lens group has a negative lens and at least two positive lenses ,
The focal length of the entire system f, the first lens focal length of the group f1, the focal length of the second lens group f2, .nu.1p the Abbe number of the material of the positive lens included in the first lens group, the second An average value of Abbe number of the negative lens material included in one lens group is ν1n, an average value of Abbe number of the positive lens material included in the second lens group is ν2p , and the negative lens included in the second lens group when the average value of Abbe numbers of the materials and Nyu2n,
−0.25 <f / f1 <0.20
0.33 <f / f2 <0.60
0.20 <ν1p / ν1n <0.70
3.00 <ν2p / ν2n <6.00
An optical system that satisfies the following conditional expression: When the refractive index based on the d-line of the material of the positive lens included in the first lens group is n1p,
1.90 <n1p <2.30
The optical system according to claim 1, wherein the following conditional expression is satisfied . The second lens group has a cemented lens in which a negative lens and a positive lens are cemented ,
When the Abbe number of the material of the negative lens constituting the cemented lens is νcn and the Abbe number of the material of the positive lens constituting the cemented lens is νcp,
3.00 <νcp / νcn <6.00
Optical system according to claim 1 or 2, characterized by satisfying the conditional expression. The second lens group has a cemented lens in which a negative lens and a positive lens are cemented ,
When the refractive index of the negative lens material constituting the cemented lens is ncn and the refractive index of the positive lens material constituting the cemented lens is ncp,
0.30 <ncn-ncp <0.60
Optical system according to claim 1 or 2, characterized by satisfying the conditional expression. The second lens group, disposed in order from the object side, a cemented lens of a negative lens and a positive lens are bonded, a positive lens, any one of claims 1 to 4, characterized in that and a positive lens 1 The optical system according to item. The second lens group, disposed in order from the object side, a cemented lens of a positive lens and a negative lens are bonded, according to any one of claims 1 to 4, characterized in that and a positive lens Optical system . The claims 1 to optical system according to any one of 6, an imaging apparatus, characterized by chromatic an imaging element, a for receiving an image formed by the optical system. When the maximum image height in the image sensor is Y and the shooting half angle of view of the optical system is ω,
0.7 <Y / {f × tan (ω)} <1.0
The image pickup apparatus according to claim 7, wherein the following conditional expression is satisfied . When the Fno the F-number of the optical system in a state of focusing the maximum image height in the previous SL imaging element Y, on an infinite object,
0.50 <f ² /(Y×Fno)<2.50 (unit: mm)
The image pickup apparatus according to claim 7 or 8, wherein the following conditional expression is satisfied .

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