JP2015114505A - Imaging lens and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging lens suited for an imaging device mounted in a mobile information terminal or the like and capable of sufficiently correcting various aberrations even during focusing on a short-distance subject, and an imaging device using the same.SOLUTION: An imaging lens including five or more lenses for forming a subject image on an imaging surface of a solid-state imaging element, comprises a front group L1 to L3 and a rear group L4 to L6 in order from an object, the lens (A) L1 arranged near the object and having positive refractive power and the lens (B) L2 arranged near the image and having negative refractive power being arranged adjacent to each other in the front group L1 to L3, an image-side surface of the lens (C) L6 closest to the image having extrema within an effective diameter in the rear group L4 to L6, the front group L1 to L3 and the rear group L4 to L6 moving toward the object during focusing on a short-distance subject relative to focusing on a long-distance subject, and positional variations during moving satisfying the following conditional expression: 1.00<MF/MR<1.80(1), where MF indicates the positional variation of the front group L1 to L3, and MR indicates the positional variation of the rear group L4 to L6.

Description

  The present invention relates to an imaging lens suitable for an imaging apparatus using a solid-state imaging device such as a CCD (Charge Coupled Devices) type image sensor or a CMOS (Complementary Meta 1-Oxide Semiconductor) type image sensor, and an imaging apparatus using the imaging lens. It is.

  2. Description of the Related Art In recent years, mobile phones and personal digital assistants equipped with an image pickup device are becoming popular as an image pickup device using a solid-state image pickup device such as a CCD image sensor or a CMOS image sensor becomes higher in performance and smaller. More recently, the displays mounted on such portable information terminals have been increased in size and definition in order to appeal high added value to users, and in response to this, the number of pixels in the image sensor has increased. Is required. However, only high performance of the display and the imaging device is insufficient to meet the user's request, and the demand for the imaging function is increasing. As a request for such an imaging function, there is a need to enable macro shooting so as to be able to focus on a short-distance subject. However, if focusing is performed on a short-distance subject by extending the imaging lens integrally, there is a problem that aberration fluctuation tends to be excessive.

  On the other hand, Patent Document 1 describes a technique that suppresses aberration fluctuations due to focusing by dividing the imaging lens into a front group and a rear group and using different feeding amounts when focusing on a short-distance subject. ing.

Japanese Patent Laid-Open No. 2004-240074

  On the other hand, there is a strong demand for downsizing of an imaging device in order to reduce the thickness of a portable information terminal or the like equipped with the imaging device. In response to such a demand, an image sensor having a small pixel size has been developed in order to reduce the size while increasing the number of pixels. However, when the pixel size of the image sensor is reduced, the amount of light that can be received by one pixel is reduced accordingly, so noise due to a decrease in the S / N ratio and image degradation due to camera shake that occurs due to a longer exposure time are problems. It becomes.

  As a countermeasure against such a problem, it is conceivable to combine a brighter imaging lens (for example, a large-diameter lens of F1.9 or less) with an imaging element having a small pixel size. However, while increasing the diameter of the lens contributes to an increase in the amount of received light, it may cause monochromatic aberrations such as spherical aberration and coma aberration, which may degrade optical performance. In addition, the large-diameter imaging lens has a problem that aberration variation is large because the light beam passage position during focusing on a short-distance subject is easily changed.

  Here, in the imaging lens described in Patent Document 1, the front group is arranged in the order of the positive first lens, the diaphragm, and the positive second lens from the object side. If you try to increase the aperture of this imaging lens as it is, spherical aberration and coma, which are greatly affected by the size of the aperture, will increase and it will be difficult to improve the performance. However, if the front group contains only a positive lens, aberration correction Is difficult. The imaging lens of Patent Document 1 is composed of three lenses in the entire system. However, when trying to increase the diameter, it is generally difficult to correct aberrations with the three-lens configuration, which may hinder high performance. There is.

  The present invention has been made in view of such problems, and is suitable for an imaging device mounted on a portable information terminal or the like, and various aberrations are corrected well even when the aperture is increased, and a short distance is achieved. An object of the present invention is to provide an imaging lens in which various aberrations are sufficiently corrected even when focusing on a subject, and an imaging apparatus using the imaging lens.

Here, although it is a scale of a small imaging lens, the present invention aims at miniaturization at a level satisfying the following expression. By satisfying this range, the entire imaging apparatus can be reduced in size and weight.
L / 2Y <1.00 (5)
However,
L: Distance on the optical axis from the lens surface closest to the object side to the image-side focal point of the entire imaging lens system 2Y: diagonal length of the imaging surface of the solid-state imaging device (diagonal length of the rectangular effective pixel region of the solid-state imaging device)
Here, the image-side focal point refers to an image point when a parallel light beam parallel to the optical axis is incident on the imaging lens.
When a parallel plate such as an optical low-pass filter, an infrared cut filter, or a seal glass of a solid-state image sensor package is disposed between the image-side surface of the imaging lens and the image-side focal position, the imaging lens is parallel. The flat plate portion is calculated as the above L value after the air conversion distance. More preferably, the range of the following formula is good.
L / 2Y <0.95 (5) '

The imaging lens according to claim 1 is an imaging lens having five or more lenses for forming a subject image on an imaging surface of a solid-state imaging device,
In order from the object side, it consists of a front group and a rear group,
In the front group, a lens (A) having a positive refractive power arranged on the object side and a lens (B) having a negative refractive power arranged on the image side from the lens (A) are adjacent to each other. Lined up
In the rear group, the image side surface of the lens (C) closest to the image side has an extreme value within the effective diameter,
The positional change amounts of the front group and the rear group satisfy the following conditional expressions when shooting a subject at a long distance and shooting a subject at a short distance.
1.00 <MF / MR <1.80 (1)
However, MF: Position change amount of the front group (mm)
MR: Position change amount of the rear group (mm)

  An imaging lens that forms a subject image on the imaging surface of a solid-state imaging device needs to suppress the incident angle of light on the imaging surface to be small in order to improve the light receiving efficiency of the solid-state imaging device. In the case of a lens with a shortened optical total length, such as an imaging lens suitable for an imaging device mounted on a relatively thin portable information terminal or the like, the exit pupil position becomes close to the image plane, so the image is formed at the peripheral image height. It becomes difficult to keep the incident angle of the incident light on the imaging surface small. According to the present invention, by providing an extreme value within the effective diameter of the image side surface of the lens (C) closest to the image in the rear group, a positive refractive power can be obtained with respect to a light beam formed at the peripheral image height. Therefore, the light incident angle on the imaging surface can be kept small.

  Conditional expression (1) defines the ratio of the amount of advance of the front group and the amount of advance of the rear group when photographing a short-distance subject with respect to photographing a long-distance subject. When photographing a short-distance subject, if the forcing by the so-called all-group equivalent feeding, in which the front group and the rear group move by the same distance, the light beam formed at the peripheral image height is applied to the near-distance subject. At the time of focusing, the lens passes through a position closer to the optical axis than at the time of focusing on an infinitely far distance (or far-distance subject) in each lens. Therefore, aberration fluctuation is likely to occur due to a change in the light beam passing position, and optical performance may be deteriorated. . Further, when the image side surface of the lens (C) closest to the image side in the rear group has an extreme value within the effective diameter, the power changes greatly from the vicinity of the center to the periphery, so the lens (C) closest to the image side. If the light passing position passing through the inside fluctuates, the generated aberration fluctuations also increase, and the optical performance may be greatly deteriorated. It should be noted that “a long-distance subject” refers to a subject at a distance exceeding 60 cm from the imaging lens, and “a short-distance subject” refers to a subject within 60 cm from the imaging lens.

On the other hand, when the value of conditional expression (1) exceeds the lower limit, the position change amount of the front group becomes larger than the position change amount of the rear group, and the front group and the rear group are focused during focusing on a short-distance subject. Since the distance between the groups is increased, the light passing position of the rear group can be separated from the optical axis. Accordingly, the light beam passing position of the rear group at the time of focusing on a short-distance subject is brought close to the position at the time of focusing on an infinitely far distance (or a long-distance subject), and therefore aberration fluctuations accompanying changes in the light ray passing position are suppressed to a small level. be able to. On the other hand, when the value of conditional expression (1) is less than the upper limit, the amount of feeding of the front group does not become too large with respect to the amount of feeding of the rear group, so the light passing position of the rear group does not change too much. Thus, it is possible to prevent the performance from deteriorating by suppressing the fluctuation of aberration. In addition, it is possible to prevent the angle of view from changing greatly between when shooting a long distance subject and when shooting a short distance subject. Preferably, the following formula is satisfied.
1.05 <MF / MR <1.60 (1 ′)

  In this way, by changing the position change amount of the front group and the rear group, it becomes possible to improve the optical performance at the time of focusing on a short-distance subject, but on the other hand, as the imaging lens is enlarged, Aberration correction tends to be difficult regardless of the distance of the subject. Therefore, by including a lens (A) having a positive refractive power in the front group, the principal point position of the entire system is brought closer to the object side, which is advantageous for shortening the optical total length, and further in the front group. By including the lens (B) having the refracting power, chromatic aberration generated in the lens (A) can be corrected. In general, spherical aberration is more prominent in a large aperture imaging lens because it is more prominent as the height of light passing through the lens is higher. According to the present invention, by arranging the lens (A) and the lens (B) next to each other, the height of the light beam passing through the lens (A) and the lens (B) becomes close, so that the lens (A ) Is easily corrected by the lens (B), which is effective in increasing the diameter of the imaging lens. The F number of the imaging lens is preferably 1.9 or less, but the present invention is effective even with an F number higher than that.

  The imaging lens according to claim 2 is the imaging lens according to claim 1, wherein the most image-side lens (C) in the rear group has a negative refractive power near the optical axis and a positive refractive power around the optical axis. It is characterized by having.

  The most image side lens (C) has a negative refractive power in the vicinity of the optical axis and has a positive refractive power in the periphery, so that it has a positive refractive power with respect to a light beam formed at the peripheral image height. Therefore, the light incident angle on the imaging surface of the solid-state imaging device can be kept small.

According to a third aspect of the present invention, in the invention of the first or second aspect, the positive refractive power of the lens (A) is the largest among the positive refractive powers of other lenses in the front group. And the following conditional expression is satisfied.
0.6 <fp / f <1.2 (2)
Where fp: focal length (mm) of the front lens group (A)
f: Focal length (mm) of the imaging lens when shooting a long-distance subject

  Conditional expression (2) defines the ratio of the focal length of the lens (A) to the focal length of the entire system. When the value of conditional expression (2) exceeds the lower limit, the lens (A) can have a strong positive refractive power, so that the principal point position of the entire system can be brought closer to the object side, and the optical total length It becomes advantageous for shortening. On the other hand, when the value of conditional expression (2) is less than the upper limit, the refractive power of the lens (A) does not become too strong, thereby suppressing the occurrence of aberrations.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the lens (B) satisfies the following conditional expression.
−2.0 <fn / f <−0.8 (3)
Where fn: focal length (mm) of the front lens group (B)
f: Focal length (mm) of the imaging lens when shooting a long-distance subject

  Conditional expression (3) defines the ratio of the focal length of the lens (B) to the focal length of the entire system. The lens (B) is disposed on the image side of the lens (A) and has a function of correcting aberrations generated in the lens (A). When the value of conditional expression (3) exceeds the lower limit, the negative refractive power of the lens (B) does not become too strong, and overcorrection of aberration can be prevented. On the other hand, when the value of conditional expression (3) is below the upper limit, the lens (B) can have a strong negative refractive power, and the aberration generated in the lens (A) can be corrected appropriately. it can.

According to a fifth aspect of the present invention, in the invention of any one of the first to fourth aspects, the following conditional expression is satisfied.
−1.0 <fp / fn <−0.3 (4)
Where fp: focal length (mm) of the front lens group (A)
fn: focal length (mm) of the lens (B) in the front group

  Conditional expression (4) defines the ratio of the focal lengths of the lens (A) and the lens (B). By satisfying the range of the conditional expression (4), the refractive power of the lens (B) becomes appropriate with respect to the refractive power of the lens (A), thereby preventing undercorrection and overcorrection of aberrations, and appropriately correcting aberrations. It can be corrected.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the lens (A) is disposed on the most object side in the front group, and the lens (B) It is arranged second from the side.

  By disposing the lens (A) and the lens (B) on the most object side, the principal point position of the entire system can be moved to the object side, which is advantageous for shortening the optical total length.

  According to a seventh aspect of the present invention, in the invention of any one of the first to sixth aspects, the imaging lens has a lens that does not substantially have refractive power. That is, even when a dummy lens having substantially no refractive power is added to the configuration of claim 1, it is within the scope of application of the present invention.

  An imaging device according to an eighth aspect includes the imaging lens according to any one of the first to seventh aspects.

  According to the present invention, it is suitable for an imaging device mounted on a portable information terminal or the like, and various aberrations are corrected well even when the aperture is increased, and the various aberrations are sufficiently corrected even when focusing on a short-distance subject. An imaging lens and an imaging apparatus using the imaging lens can be provided.

1 is a perspective view of an imaging unit (imaging device) 50 according to the present embodiment. 3 is a diagram schematically showing a cross section along the optical axis of an imaging lens of the imaging unit 50. FIG. It is the front view (a) of the smart phone as a portable terminal to which an imaging unit is applied, and the back view (b) of the smart phone to which the imaging unit is applied. It is a control block diagram of the smart phone of FIG. 3 is a cross-sectional view in the optical axis direction of the imaging lens of Example 1. FIG. 6 is a cross-sectional view in the optical axis direction of the imaging lens of Comparative Example 1. FIG. FIG. 6 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), meridional coma aberration (d), (e)) during infinite distance focusing in Example 1 and Comparative Example 1. . FIG. 4 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion (c), meridional coma aberration (d), (e)) at the time of focusing on a short-distance subject in Example 1. FIG. 7A is an aberration diagram (spherical aberration (a), astigmatism (b), distortion (c), meridional coma aberration (d), (e)) at the time of short-distance object focusing in Comparative Example 1; FIG. 6 is a cross-sectional view in the optical axis direction of the imaging lens of Example 2. 6 is a cross-sectional view in the optical axis direction of an imaging lens of Comparative Example 2. FIG. FIG. 6 is aberration diagrams (spherical aberration (a), astigmatism (b), distortion aberration (c), meridional coma aberration (d), (e)) during focusing on infinity according to Example 2 and Comparative Example 2. . FIG. 6 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion (c), meridional coma aberration (d), (e)) at the time of focusing on a short-distance subject in Example 2. FIG. 9A is an aberration diagram (spherical aberration (a), astigmatism (b), distortion (c), meridional coma aberration (d), (e)) at the time of short-distance object focusing in Comparative Example 2. 6 is a cross-sectional view in the optical axis direction of the imaging lens of Embodiment 3. FIG. 10 is a cross-sectional view in the optical axis direction of an imaging lens of Comparative Example 3. FIG. FIG. 6 is aberration diagrams (spherical aberration (a), astigmatism (b), distortion aberration (c), meridional coma aberration (d), (e)) during focusing on infinity according to Example 3 and Comparative Example 3. . FIG. 10 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion (c), meridional coma aberration (d), (e)) at the time of focusing on a short distance object according to the third embodiment. FIG. 7A is an aberration diagram (spherical aberration (a), astigmatism (b), distortion (c), meridional coma aberration (d), (e)) at the time of short-distance object focusing in Comparative Example 3; 6 is a cross-sectional view in the optical axis direction of an imaging lens of Example 4. FIG. 10 is a cross-sectional view in the optical axis direction of an imaging lens of Comparative Example 4. FIG. FIG. 6 is aberration diagrams (spherical aberration (a), astigmatism (b), distortion aberration (c), meridional coma aberration (d), (e)) during focusing on infinity according to Example 4 and Comparative Example 4. . FIG. 9A is an aberration diagram (spherical aberration (a), astigmatism (b), distortion (c), meridional coma aberration (d), (e)) at the time of focusing on a short distance object according to the fourth example. FIG. 9A is an aberration diagram (spherical aberration (a), astigmatism (b), distortion (c), meridional coma aberration (d), (e)) at the time of short-distance object focusing in Comparative Example 4; 6 is a cross-sectional view in the optical axis direction of the imaging lens of Example 5. FIG. 10 is a cross-sectional view in the optical axis direction of an imaging lens of Comparative Example 5. FIG. FIG. 6 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), meridional coma aberration (d), (e)) during focusing on infinity according to Example 5 and Comparative Example 5. . FIG. 9A is an aberration diagram (spherical aberration (a), astigmatism (b), distortion (c), meridional coma aberration (d), (e)) at the time of focusing on a short distance object according to the fifth embodiment. FIG. 9A is an aberration diagram (spherical aberration (a), astigmatism (b), distortion (c), meridional coma aberration (d), (e)) at the time of short-distance object focusing in Comparative Example 5.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of an imaging unit (imaging device) 50 according to the present embodiment, and FIG. 2 is a diagram schematically showing a cross section along the optical axis of the imaging lens of the imaging unit 50.

  As shown in FIG. 2, the imaging unit 50 includes a CMOS type imaging device 51 as a solid-state imaging device having a photoelectric conversion unit 51a, an imaging lens 10 that causes the photoelectric conversion unit 51a of the imaging device 51 to capture a subject image, A lens barrel 53 that holds the imaging lens 10, a parallel plate-like optical filter 54 disposed between the imaging lens 10 and the imaging element 51, a first actuator 55 that drives the front group of the imaging lens 10, and an imaging lens 10 includes a second actuator 56 that drives the rear group 10, a substrate 52 on which the image sensor 51 is mounted, and a base member 57 that holds the optical filter 54 and connects the lens barrel 53 and the substrate 52.

  As shown in FIG. 2, the imaging element 51 has a photoelectric conversion part 51 a as a light receiving part in which pixels (photoelectric conversion elements) are two-dimensionally arranged at the center of the plane on the light receiving side. A signal processing circuit (not shown) is formed around the periphery. Such a signal processing circuit includes a drive circuit unit that sequentially drives each pixel to obtain a signal charge, an A / D conversion unit that converts each signal charge into a digital signal, and a signal that forms an image signal output using the digital signal. It consists of a processing unit and the like. In addition, a large number of pads (not shown) are arranged in the vicinity of the outer edge of the plane on the light receiving side of the image sensor 51, and are connected to the substrate 52 via wires (not shown). The image sensor 51 converts the signal charge from the photoelectric conversion unit 51a into an image signal such as a digital YUV signal, and outputs it to a predetermined circuit on the substrate 52 through a wire. Here, Y is a luminance signal, U (= R−Y) is a color difference signal between red and the luminance signal, and V (= BY) is a color difference signal between blue and the luminance signal. Note that the image sensor is not limited to the above CMOS image sensor, and other devices such as a CCD may be used.

  On the object side of the lens barrel 53, an object side wall 53a provided with a small opening (here, an aperture stop) S is formed.

The imaging lens 10 disposed in the lens barrel 53 includes, in order from the object side, a first lens L1 having positive refractive power (here, lens A) and a second lens L2 having negative refractive power (here, lens B). ), The third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 (here, the lens C) in which the image side surface has an extreme value within the effective diameter. The lenses L1 to L3 constituting the front group have a flange portion held by the first holder HD1 and can be moved in the optical axis direction by the first actuator 55. Further, the lenses L4 to L6 constituting the rear group have flange portions held by the second holder HD2, and can be moved in the optical axis direction by the second actuator 56. The imaging lens 10 moves toward the object side in the optical axis direction so that the front group and the rear group satisfy the following conditional expression when shooting a short-distance subject when shooting a long-distance subject.
1.00 <MF / MR <1.80 (1)
However, MF: Position change amount of front group (mm)
MR: Rear group position change (mm)

  The operation of the imaging unit 50 described above will be described. FIG. 3 is a diagram illustrating a state in which the imaging unit 50 is mounted on the smartphone 100 as a mobile terminal. FIG. 4 is a control block diagram of the smartphone 100.

  In the imaging unit 50, for example, the object-side end surface of the lens barrel 53 is provided on the back surface of the smartphone 100 (see FIG. 3B), and is disposed at a position corresponding to the back side of the touch panel 70.

  The imaging unit 50 is connected to the control unit 101 of the smartphone 100 and outputs an image signal such as a luminance signal or a color difference signal to the control unit 101 side.

  On the other hand, as shown in FIG. 4, the smartphone 100 performs overall control of each unit, and also inputs a control unit (CPU) 101 that executes a program corresponding to each process, and inputs a number and the like with a key. Unit 60, liquid crystal display unit 70 for displaying captured images and the like in addition to predetermined data, wireless communication unit 80 for realizing various information communications with an external server, and system programs and various types of smartphone 100 A storage unit (ROM) 91 that stores necessary data such as a processing program and a terminal ID, and various processing programs and data executed by the control unit 101, or processing data, or imaging obtained by the imaging unit 50 And a temporary storage unit (RAM) 92 that is used as a work area for temporarily storing data and the like.

  The smartphone 100 operates by operating the input key unit 60, and touches an icon 71 or the like displayed on the touch panel (display unit) 70, whereby the imaging unit 50 can be operated to perform imaging. At this time, by driving the actuators 55 and 56, it is possible to perform focusing from an infinite distance to a short distance subject. The image signal input from the imaging unit 50 is subjected to image processing to be described later in the control unit 101, stored in the storage unit 92 or displayed on the touch panel 70 by the control system of the smartphone 100, and wirelessly It is transmitted to the outside as video information via the communication unit 80.

(Example)
Next, examples suitable for the above-described embodiment will be described. However, the present invention is not limited to the following examples. The meaning of each code | symbol in an Example is as follows (a unit of length is mm other than a wavelength).
FL: Focal length of the entire imaging lens system (mm)
Fno: F number w: Half angle of view (°)
Ymax: half the diagonal length of the imaging surface of the solid-state imaging device (maximum image height: mm)
BF: Back focus (mm) (distance on the optical axis from the lens surface closest to the object side to the image plane in the entire imaging lens system)
TL: Optical total length (mm)
BFa: Back focus (mm) (distance from the lens surface closest to the object side of the entire imaging lens system to the image plane. However, the distance on the optical axis to the paraxial image plane when the cover glass is an air conversion length)
TLa: optical total length (mm) (distance on the optical axis from the lens surface closest to the object side of the entire imaging lens system to the image plane. However, the optical axis to the paraxial image plane when the cover glass is an air-converted length. Distance above)
r: radius of curvature of refractive surface (mm)
d: Distance between shaft upper surfaces (mm)
nd: Refractive index of lens material at d-line at room temperature vd: Abbe number of lens material STO: Aperture stop

  In each embodiment, the surface described with “*” after each surface number is a surface having an aspheric shape, and the shape of the aspheric surface has the vertex of the surface as the origin and the X axis in the optical axis direction. The height in the direction perpendicular to the optical axis is h, and is expressed by the following “Equation 1”.

ただし、
Ａｉ：ｉ次の非球面係数
Ｒ ：曲率半径
Ｋ ：円錐定数
である。

However,
Ai: i-th order aspherical coefficient R: radius of curvature K: conic constant.

In the following (including the lens data in the table), a power of 10 (for example, 2.5 × 10 ⁻⁰² ) is expressed using E (for example, 2.5e−002). The surface number of the lens data was given in order with the object side of the first lens as one surface. In addition, the unit of the numerical value showing the length as described in an Example shall be mm.

  In addition, regarding the implication of the paraxial radius of curvature described in the claims and examples, in the actual lens measurement scene, in the vicinity of the center of the lens (specifically, the central region within 10% of the lens effective diameter). The approximate radius of curvature when the measured shape of the shape is fitted by the method of least squares can be regarded as the paraxial radius of curvature. For example, when a secondary aspherical coefficient is used, a radius of curvature that takes into account the secondary aspherical coefficient in the reference curvature radius of the aspherical definition formula can be regarded as a paraxial curvature radius. (For example, see references 41 to 42 of Yoshiya Matsui's “Lens Design Method” (Kyoritsu Publishing Co., Ltd.) for reference)

(Example 1 and Comparative Example 1)
Table 1 shows lens data in Example 1 and Comparative Example 1. FIG. 5 is a cross-sectional view of the lens of Example 1, and FIG. 6 is a cross-sectional view of the lens of Comparative Example 1. The lens shape is the same as in Example 1 and Comparative Example 1, and the lens position when focusing to infinity is also common. However, when focusing on a short-distance subject, Example 1 differs in the amount of extension of the front group and the rear group, and Comparative Example 1 has the same amount of extension for all groups. 5 and 6, the solid line indicates the lens position, the imaging surface position, and the optical path when focusing on a short-distance subject (10 cm from the imaging lens), and the alternate long and short dash line indicates the lens position, imaging surface position, and optical path when focusing on infinity. Yes. For easy comparison, FIGS. 5 and 6 show that the imaging lens side (lenses L4 to L6 in FIG. 5) is fixed and the imaging surface is relatively moved.

  The imaging lenses of Example 1 and Comparative Example 1 have an aperture stop S, a first lens L1 having a positive refractive power (lens A), and a second lens L2 having a negative refractive power (lens B) in order from the object side. The third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 (lens C) whose image side surface has an extreme value within the effective diameter. The positive refractive power of the first lens L1 is the strongest in the front group, and the sixth lens L6 has a negative refractive power in the vicinity of the optical axis and a positive refractive power in the periphery. F is a parallel plate assuming a cover glass or an IR cut filter, and I is an imaging surface of the solid-state imaging device. In Example 1, the lenses L1 to L3 constitute the front group, and the lenses L4 to L6 constitute the rear group.

[table 1]
[Example 1]
Reference Wave Length = 587.56 nm

Surface data surface number rd nd vd Effective diameter
STO INFINITY 0.0500 2.700
2 * 2.0164 0.7001 1.54470 56.2 2.625
3 * -9.8401 0.0681 2.489
4 * 1.9159 0.1548 1.63469 23.9 2.263
5 * 1.1239 0.4595 2.046
6 INFINITY 0.2000 2.002
7 * -20.2537 0.4142 1.54470 56.2 2.203
8 * -6.3415 VARIABLE 2.532
9 * 2.4936 0.2000 1.63469 23.9 3.088
10 * 1.9276 0.3004 3.406
11 * 7.8447 0.9846 1.54470 56.2 3.597
12 * -1.3875 0.3194 3.847
13 * 7.4959 0.3225 1.54470 56.2 5.062
14 * 1.0490 0.7000 5.336
15 INFINITY 0.1100 1.51633 64.1 6.000
16 INFINITY VARIABLE 6.000

Aspheric coefficient
2: K = 5.34931e-001, A4 = -1.69769e-003, A6 = 1.63552e-003, A8 = -1.19855e-002, A10 = 1.49150e-002, A12 = -8.23861e-003, A14 = 1.86134 e-003
3: K = -7.50627e + 001, A4 = 9.15739e-002, A6 = -1.12007e-001, A8 = 1.14533e-001, A10 = -7.65568e-002, A12 = 2.95866e-002, A14 =- 4.87500e-003
4: K = -1.59992e + 001, A4 = 1.39545e-002, A6 = -3.81141e-002, A8 = 5.61809e-002, A10 = -4.79593e-002, A12 = 1.90519e-002, A14 =- 3.54001e-003
5: K = -4.86945e + 000, A3 = -1.12825e-002, A4 = 1.09747e-002, A5 = 2.78450e-002, A6 = 4.62375e-002, A8 = -1.16515e-001, A10 = 1.49399 e-001, A12 = -1.01912e-001, A14 = 2.83205e-002
7: K = -4.82385e + 001, A3 = -1.07910e-002, A4 = 4.07725e-002, A5 = -1.40323e-001, A6 = 1.33801e-001, A8 = -1.67791e-001, A10 = 1.83451e-001, A12 = -1.11716e-001, A14 = 2.51870e-002
8: K = -8.00000e + 001, A3 = -2.10832e-002, A4 = -6.64680e-002, A5 = 9.42365e-002, A6 = -1.18450e-001, A8 = 3.68282e-002, A10 = -8.95217e-004, A12 = -5.41019e-003
9: K = 1.32838e-001, A3 = -1.75807e-002, A4 = -3.09421e-001, A5 = 3.68096e-001, A6 = -2.67632e-001, A8 = 9.92310e-002, A10 =- 2.69240e-002, A12 = 2.68515e-003
10: K = 5.46443e-002, A3 = -2.69423e-002, A4 = -2.49595e-001, A5 = 1.56177e-001, A6 = -5.38703e-002, A8 = 1.57095e-003, A10 = 6.10817 e-003, A12 = -2.46515e-003, A14 = 2.16168e-004
11: K = -5.85358e + 001, A3 = -2.30635e-002, A4 = 8.25686e-002, A5 = -1.48628e-001, A6 = 9.27047e-002, A8 = -3.86835e-002, A10 = 1.64803e-002, A12 = -3.56651e-003, A14 = 3.08117e-004
12: K = -8.00463e + 000, A3 = -6.22701e-002, A4 = -8.42285e-002, A5 = 8.55637e-002, A6 = -1.52955e-002, A8 = -1.44000e-002, A10 = 7.06880e-003, A12 = -1.15541e-003, A14 = 5.92561e-005
13: K = 5.78031e + 000, A3 = -1.64712e-001, A4 = -9.25534e-002, A5 = 4.02699e-002, A6 = 2.35776e-002, A8 = -2.78645e-003, A10 =- 3.66823e-004, A12 = 8.01289e-005, A14 = -4.00882e-006
14: K = -5.94778e + 000, A3 = -3.08084e-002, A4 = -1.18894e-001, A5 = 9.88842e-002, A6 = -2.71705e-002, A8 = 9.54064e-004, A10 = -1.17795e-004, A12 = 2.49313e-005, A14 = -1.55834e-006

FL 3.784
Fno 1.44
w 75.43
Ymax 2.921
BF 0.909
TL 5.183
BFa 0.872
TLa 5.145

Focusing distance INF 10cm 10cm all groups extended (comparative example)
d8 0.1000 0.1451 0.1000
d16 0.0992 0.2196 0.2459

Elem Surfs Focal Length Diameter
1 2- 3 3.1376 2.625
2 4- 5 -4.6355 2.263
3 7-8 16.7730 2.532
4 9-10 -15.5096 3.406
5 11-12 2.2490 3.847
6 13-14 -2.2794 5.336

  FIG. 7 is an aberration diagram at the time of infinity focusing in Example 1 and Comparative Example 1 (spherical aberration (a), astigmatism (b), distortion (c), meridional coma (d), (e). ). FIG. 8 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), meridional coma aberration (d), (e)) at the time of focusing on a short distance object in Example 1. . FIG. 9 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), meridional coma aberration (d), (e)) at the time of short-distance object focusing in Comparative Example 1. . Here, in the spherical aberration diagram and the meridional coma aberration diagram, the solid line represents the amount of spherical aberration with respect to the d-line and the dotted line, respectively, and in the astigmatism diagram, the solid line S represents the sagittal surface and the dotted line M represents the meridional surface. Represent (hereinafter the same).

  Comparing FIGS. 5 and 6, in Example 1 in which the feeding amount of the front group is larger than that of the rear group compared to Comparative Example 1 in which all groups are fed out, the optical path (solid line) during infinitely far focusing is The amount of fluctuation in the direction perpendicular to the optical axis of the optical path (one-dot chain line) during short-distance subject focusing is small. Therefore, fluctuations in the light incident position of each lens are suppressed regardless of the subject distance. As a result, as is apparent from a comparison between FIGS.

(Example 2 and Comparative Example 2)
Table 2 shows lens data in Example 2 and Comparative Example 2. 10 is a cross-sectional view of the lens of Example 2, and FIG. 11 is a cross-sectional view of the lens of Comparative Example 2. In Example 2 and Comparative Example 2, the lens shape is common, and the lens position when focusing to infinity is also common. However, when focusing on a short-distance subject, the amount of extension in the front group and the rear group is different in Example 2, and the amount of extension in all groups is equal in Comparative Example 2. 10 and 11, the solid line indicates the lens position, the imaging surface position, and the optical path when focusing on a short-distance subject (10 cm from the imaging lens), and the alternate long and short dash line indicates the lens position, imaging surface position, and optical path when focusing on infinity. Yes. For easy comparison, in FIGS. 10 and 11, the imaging lens side (lenses L5 to L6 in FIG. 10) is fixed and the imaging surface is relatively moved.

  The imaging lenses of Example 2 and Comparative Example 2 have an aperture stop S, a first lens L1 having a positive refractive power (lens A), and a second lens L2 having a negative refractive power (lens B) in order from the object side. The third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 (lens C) whose image side surface has an extreme value within the effective diameter. The positive refractive power of the first lens L1 is the strongest in the front group, and the sixth lens L6 has a negative refractive power in the vicinity of the optical axis and a positive refractive power in the periphery. F is a parallel plate assuming a cover glass or an IR cut filter, and I is an imaging surface of the solid-state imaging device. In Example 2, the lenses L1 to L4 constitute the front group, and the lenses L5 to L6 constitute the rear group.

[Table 2]
[Example 2]
Surface data surface number rd nd vd Effective diameter
STO INFINITY 0.0500 2.625
2 * 2.0091 0.6952 1.54470 56.2 2.640
3 * -10.4799 0.0740 2.512
4 * 1.9937 0.1542 1.63469 23.9 2.291
5 * 1.1620 0.4005 2.074
6 INFINITY 0.1400 2.129
7 * 4208.7895 0.4097 1.54470 56.2 2.244
8 * -56.7294 0.1000 2.490
9 * 2.5035 0.2000 1.63469 23.9 2.625
10 * 2.3858 VARIABLE 2.943
11 * 12.6375 0.9737 1.54470 56.2 3.367
12 * -1.3092 0.3286 3.814
13 * 8.3099 0.3223 1.54470 56.2 5.126
14 * 1.0423 0.7000 5.375
15 INFINITY 0.1100 1.51633 64.1 5.763
16 INFINITY VARIABLE 5.810

Aspheric coefficient
2: K = 1.57279e-001, A4 = 3.94752e-003, A6 = 2.83183e-003, A8 = -9.37735e-003, A10 = 1.29937e-002, A12 = -7.46045e-003, A14 = 1.83372e -003
3: K = -5.50362e + 001, A4 = 9.45062e-002, A6 = -1.13062e-001, A8 = 1.15232e-001, A10 = -7.80785e-002, A12 = 3.06439e-002, A14 =- 5.06147e-003
4: K = -1.69116e + 001, A4 = 1.64439e-002, A6 = -3.75357e-002, A8 = 5.35850e-002, A10 = -4.41587e-002, A12 = 1.82114e-002, A14 =- 3.54001e-003
5: K = -5.56093e + 000, A3 = 6.26744e-004, A4 = 2.34287e-002, A5 = 1.53577e-002, A6 = 3.01794e-002, A8 = -1.01448e-001, A10 = 1.55943e -001, A12 = -1.15852e-001, A14 = 3.41357e-002
7: K = 8.00000e + 001, A3 = -1.63174e-002, A4 = 6.28962e-002, A5 = -1.50417e-001, A6 = 1.34480e-001, A8 = -1.60432e-001, A10 = 1.78874 e-001, A12 = -1.14292e-001, A14 = 2.61146e-002
8: K = 8.00000e + 001, A3 = -8.56030e-002, A4 = -1.93295e-002, A5 = 8.80337e-002, A6 = -1.29806e-001, A8 = 2.75352e-002, A10 = 3.20224 e-003, A12 = -6.07380e-003
9: K = -3.39979e + 000, A3 = -7.07642e-002, A4 = -3.45283e-001, A5 = 3.77120e-001, A6 = -2.87979e-001, A8 = 8.54697e-002, A10 = -2.20272e-002, A12 = 5.44002e-003
10: K = 1.26619e + 000, A3 = -3.55406e-002, A4 = -2.77981e-001, A5 = 1.26735e-001, A6 = -5.06670e-002, A8 = 3.83498e-003, A10 = 4.81753 e-003, A12 = -2.53396e-003, A14 = 2.04537e-004
11: K = -8.00000e + 001, A3 = -1.80134e-002, A4 = 5.24632e-002, A5 = -1.07760e-001, A6 = 7.59798e-002, A8 = -4.05601e-002, A10 = 1.80609e-002, A12 = -4.19070e-003, A14 = 3.13615e-004
12: K = -7.51540e + 000, A3 = -7.10944e-002, A4 = -8.92430e-002, A5 = 9.31586e-002, A6 = -1.36116e-002, A8 = -1.59368e-002, A10 = 7.09451e-003, A12 = -1.07278e-003, A14 = 3.14152e-005
13: K = 7.73185e + 000, A3 = -1.55686e-001, A4 = -9.05406e-002, A5 = 3.86140e-002, A6 = 2.28519e-002, A8 = -2.77300e-003, A10 =- 3.55190e-004, A12 = 8.08088e-005, A14 = -4.15519e-006
14: K = -6.01675e + 000, A3 = -1.64177e-002, A4 = -1.32244e-001, A5 = 1.01778e-001, A6 = -2.65959e-002, A8 = 8.39264e-004, A10 = -1.30386e-004, A12 = 2.55692e-005, A14 = -1.40288e-006

FL 3.778
Fno 1.44
w 75.42
Ymax 2.921
BF 0.914
TL 5.172
BFa 0.877
TLa 5.135

Focusing distance INF 10cm 10cm all groups extended (comparative example)
d10 0.4099 0.4514 0.4099
d16 0.1043 0.2386 0.2495

Elem Surfs Focal Length Diameter
1 2- 3 3.1570 2.640
2 4- 5 -4.7290 2.291
3 7- 8 102.7664 2.490
4 9-10 -234.7668 2.943
5 11-12 2.2329 3.814
6 13-14 -2.2227 5.375

  FIG. 12 is an aberration diagram in Example 2 and Comparative Example 2 during focusing at infinity (spherical aberration (a), astigmatism (b), distortion (c), meridional coma (d), (e). ). FIG. 13 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), meridional coma aberration (d), (e)) at the time of focusing on a short distance object in Example 2. . FIG. 14 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), meridional coma aberration (d), (e)) at the time of short-distance object focusing in Comparative Example 2. .

  When comparing FIGS. 10 and 11, in Example 2 in which the feeding amount of the front group is larger than that of the rear group, compared to Comparative Example 2 in which all groups are fed out, the optical path (solid line) during infinitely far focusing is The amount of fluctuation in the direction perpendicular to the optical axis of the optical path (one-dot chain line) during short-distance subject focusing is small. Therefore, fluctuations in the light incident position of each lens are suppressed regardless of the subject distance. As a result, as is apparent from a comparison between FIGS.

(Example 3 and Comparative Example 3)
Table 3 shows lens data in Example 3 and Comparative Example 3. 15 is a cross-sectional view of the lens of Example 3, and FIG. 16 is a cross-sectional view of the lens of Comparative Example 3. In Example 3 and Comparative Example 3, the lens shape is common, and the lens position when focusing to infinity is also common. However, when focusing on a short-distance subject, the amount of extension in the front group and the rear group is different in Example 3, and the amount of extension in all groups is equal in Comparative Example 3. 15 and 16, the solid line indicates the lens position, the imaging surface position, and the optical path when focusing on a short-distance subject (10 cm from the imaging lens), and the alternate long and short dash line indicates the lens position, imaging surface position, and optical path when focusing on infinity. Yes. For ease of comparison, in FIGS. 15 and 16, the imaging lens side (lenses L4 to L5 in FIG. 15) is fixed and the imaging surface is relatively moved.

  The imaging lenses of Example 3 and Comparative Example 3 have an aperture stop S, a first lens L1 having a positive refractive power (lens A), and a second lens L2 having a negative refractive power (lens B) in order from the object side. The third lens L3, the fourth lens L4, and the fifth lens L5 (lens C) whose image side surface has an extreme value within the effective diameter. The positive refractive power of the first lens L1 is the strongest in the front group, and the fifth lens L5 has a negative refractive power in the vicinity of the optical axis and a positive refractive power in the periphery. F is a parallel plate assuming a cover glass or an IR cut filter, and I is an imaging surface of the solid-state imaging device. In Example 3, the lenses L1 to L3 constitute the front group, and the lenses L4 to L5 constitute the rear group.

[Table 3]
[Example 3]
Surface data surface number rd nd vd Effective diameter
STO INFINITY 0.0500 1.966
2 INFINITY -0.3683 1.966
3 * 1.5591 0.5338 1.54470 56.2 1.968
4 * 33.4902 0.0778 1.862
5 * 4.6119 0.1700 1.63469 23.9 1.864
6 * 1.8613 0.4656 1.857
7 * 8.9390 0.4826 1.54470 56.2 2.185
8 * INFINITY VARIABLE 2.448
9 * -17.0704 0.7113 1.54470 56.2 2.765
10 * -1.2674 0.4855 3.361
11 * -1.4052 0.3142 1.54470 56.2 4.761
12 * 3.6294 0.4090 5.008
13 INFINITY 0.1100 1.51633 64.1 5.653
14 INFINITY VARIABLE 5.706

Aspheric coefficient
3: K = 9.16290e-002, A4 = 2.03102e-003, A6 = 1.96915e-002, A8 = -3.07399e-002, A10 = 2.63591e-000
4: K = -1.00000e + 000, A4 = -6.23278e-002, A6 = 2.39862e-001, A8 = -3.66397e-001, A10 = 3.20886e-001, A12 = -1.18037e-001
5: K = 1.00000e + 000, A4 = -2.46567e-001, A6 = 5.69834e-001, A8 = -7.16893e-001, A10 = 5.32203e-001, A12 = -1.92818e-001
6: K = -2.27497e + 001, A4 = 1.99084e-001, A6 = -3.16574e-001, A8 = 6.64830e-001, A10 = -6.33466e-001, A12 = 2.48060e-001
7: K = 8.66996e + 000, A4 = -7.91911e-002, A6 = -7.64850e-002, A8 = 2.73329e-001, A10 = -4.46972e-001, A12 = 3.43230e-001, A14 =- 9.00657e-002
8: K = 0.00000e + 000, A4 = -9.58045e-002, A6 = 5.96433e-002, A8 = -1.34169e-001, A10 = 1.45786e-001, A12 = -9.36522e-002, A14 = 2.77093 e-002
9: K = 1.00000e + 000, A4 = -8.88838e-002, A6 = 4.32356e-002, A8 = -3.56913e-002, A10 = 1.35533e-002, A12 = -4.27958e-003,
10: K = -3.09525e + 000, A3 = 3.51468e-002, A4 = -1.11481e-001, A5 = 1.44454e-002, A6 = 2.95663e-002, A8 = 2.84472e-003, A10 = -2.85087 e-003, A12 = -1.56050e-005, A14 = 8.26462e-005
11: K = -1.03625e + 000, A3 = 5.10144e-002, A4 = 7.28045e-003, A5 = 2.58949e-003, A6 = 2.03721e-003, A8 = -2.00746e-004, A10 = -2.56243 e-005, A12 = 3.09141e-006, A14 = 1.52126e-008
12: K = -4.00000e + 001, A3 = 3.23445e-003, A4 = -2.08383e-002, A5 = -1.42851e-003, A6 = 3.01963e-003, A8 = -6.14877e-004, A10 = -4.68535e-006, A12 = 4.94715e-006, A14 = 2.73261e-007

FL 3.719
Fno1.85
w 75.78
Ymax 2.921
BF 0.740
TL 4.500
BFa 0.703
TLa 4.462

Focusing distance INF 10cm 10cm all groups extended (comparative example)
d8 0.5190 0.5504 0.5190
d14 0.2210 0.3390 0.3640

Elem Surfs Focal Length Diameter
1 3- 4 2.9844 1.968
2 5- 6 -5.0380 1.864
3 7-8 16.4109 2.448
4 9-10 2.4741 3.361
5 11-12 -1.8197 5.008

  FIG. 17 is an aberration diagram in Example 3 and Comparative Example 3 during focusing at infinity (spherical aberration (a), astigmatism (b), distortion (c), meridional coma (d), (e). ). FIG. 18 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), meridional coma aberration (d), (e)) at the time of focusing on a short distance object in Example 3. . FIG. 19 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), meridional coma aberration (d), (e)) at the time of short-distance object focusing in Comparative Example 3. .

  15 and 16, in Example 3 in which the amount of feeding of the front group is larger than that of the rear group, compared to Comparative Example 3 in which all the groups are fed out equally, with respect to the optical path (solid line) at infinity focusing, The amount of fluctuation in the direction perpendicular to the optical axis of the optical path (one-dot chain line) during short-distance subject focusing is small. Therefore, fluctuations in the light incident position of each lens are suppressed regardless of the subject distance. This makes it possible to suppress fluctuations in aberrations as is apparent when comparing FIGS.

(Example 4 and Comparative Example 4)
Table 4 shows lens data in Example 4 and Comparative Example 4. 20 is a cross-sectional view of the lens of Example 4, and FIG. 21 is a cross-sectional view of the lens of Comparative Example 4. The lens shape is the same as in Example 4 and Comparative Example 4, and the lens position when focusing to infinity is also common. However, when focusing on a short-distance subject, the amount of extension in the front group and the rear group is different in Example 4, and the amount of extension in all groups is equal in Comparative Example 4. 20 and 21, a solid line indicates a lens position, an imaging surface position, and an optical path at the time of focusing on a short-distance subject (10 cm from the imaging lens), and an alternate long and short dash line indicates a lens position, an imaging surface position, and an optical path at the time of infinity focusing. Yes. For easy comparison, in FIGS. 20 and 21, the imaging lens side (lenses L4 to L7 in FIG. 20) is fixed and the imaging surface is relatively moved.

  The imaging lenses of Example 4 and Comparative Example 4 have an aperture stop S, a first lens L1 having a positive refractive power (lens A), and a second lens L2 having a negative refractive power (lens B) in order from the object side. The third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 (lens C) whose image side surface has an extreme value within the effective diameter. The positive refractive power of the first lens L1 is the strongest in the front group, and the seventh lens L7 has a negative refractive power in the vicinity of the optical axis and a positive refractive power in the periphery. F is a parallel plate assuming a cover glass or an IR cut filter, and I is an imaging surface of the solid-state imaging device. In Example 4, the lenses L1 to L3 constitute the front group, and the lenses L4 to L7 constitute the rear group.

[Table 4]
[Example 4]
Surface data surface number rd nd vd Effective diameter
STO INFINITY -0.2468 3.137
2 * 2.5005 0.8252 1.54470 56.2 3.137
3 * -10.5043 0.0718 2.988
4 * 2.6081 0.2266 1.63469 23.9 2.737
5 * 1.4393 0.5242 2.453
6 INFINITY 0.2000 2.400
7 * 23.9779 0.4466 1.54470 56.2 2.632
8 * 7.8472 VARIABLE 3.002
9 * 3.2992 0.5111 1.54470 56 3.333
10 * 7.5547 0.2288 3.635
11 * 10.3299 0.2138 1.63469 23.9 3.873
12 * 4.9745 0.2789 4.120
13 * 5.5829 0.8481 1.54470 56.2 4.741
14 * -1.5801 0.4134 5.020
15 * -836.4626 0.2500 1.54470 56.2 5.810
16 * 1.3124 0.5000 6.427
17 INFINITY 0.1100 1.51633 64.1 6.871
18 INFINITY VARIABLE 6.906

Aspheric coefficient
2: K = -8.58477e-001, A4 = 1.03455e-002, A6 = 1.30099e-003, A8 = -1.42416e-003, A10 = 1.44662e-003, A12 = -5.38962e-004, A14 = 8.43901 e-005
3: K = -2.78060e + 001, A4 = 5.39696e-002, A6 = -4.34311e-002, A8 = 2.93926e-002, A10 = -1.32923e-002, A12 = 3.38565e-003, A14 =- 3.54697e-004
4: K = -1.78152e + 001, A4 = 1.12075e-002, A6 = -1.45352e-002, A8 = 1.38363e-002, A10 = -8.31398e-003, A12 = 2.47222e-003, A14 =- 2.69677e-004
5: K = -5.50379e + 000, A3 = 6.89480e-003, A4 = 6.89728e-003, A5 = 8.71157e-003, A6 = 1.76812e-002, A8 = -3.27725e-002, A10 = 2.87104e -002, A12 = -1.28716e-002, A14 = 2.37434e-003
7: K = -8.00000e + 001, A3 = -8.41064e-003, A4 = 8.77150e-003, A5 = -8.63565e-002, A6 = 8.73777e-002, A8 = -5.06460e-002, A10 = 2.24718e-002, A12 = -5.61849e-003, A14 = 1.30266e-004
8: K = 6.45596e + 000, A3 = -2.79513e-002, A4 = -9.44470e-002, A5 = 1.61763e-003, A6 = 2.29949e-002, A8 = -1.03711e-002, A10 = 1.18597 e-003, A12 = 7.46164e-004, A14 = -3.05680e-004
9: K = 4.93077e-001, A3 = -4.30472e-002, A4 = -8.12464e-002, A5 = 3.87714e-003, A6 = -5.61064e-003, A8 = 5.94585e-004, A10 = 1.11085 e-003, A12 = 1.53276e-004, A14 = -9.17525e-005
10: K = 5.73009e + 000, A3 = -4.20274e-002, A4 = -2.87745e-002, A5 = 2.26675e-002, A6 = -4.77060e-002, A8 = 1.42891e-002, A10 =- 2.19953e-003, A12 = 1.49437e-004
11: K = 1.83030e + 001, A3 = -3.41979e-002, A4 = -1.86978e-001, A5 = 1.62864e-001, A6 = -9.99240e-002, A8 = 2.52099e-002, A10 =- 3.20768e-003, A12 = 1.09667e-004
12: K = -1.22428e + 001, A3 = -2.82690e-002, A4 = -1.46417e-001, A5 = 7.21508e-002, A6 = -1.80970e-002, A8 = 1.49407e-003, A10 = 1.07675e-003, A12 = -2.46954e-004, A14 = 1.19441e-005
13: K = -9.05324e + 000, A3 = -7.57649e-003, A4 = 6.71306e-003, A5 = -5.41252e-002, A6 = 4.40156e-002, A8 = -1.17892e-002, A10 = 2.49719e-003, A12 = -3.02804e-004, A14 = 1.58749e-005
14: K = -8.67402e + 000, A3 = -4.68660e-002, A4 = -3.51226e-002, A5 = 4.50630e-002, A6 = -2.89400e-003, A8 = -4.45024e-003, A10 = 1.08800e-003, A12 = -1.25626e-004, A14 = 5.87838e-006
15: K = 8.00000e + 001, A3 = -8.52558e-002, A4 = -5.10832e-002, A5 = 1.76136e-002, A6 = 8.35488e-003, A8 = -7.35427e-004, A10 =- 5.72577e-005, A12 = 9.52801e-006, A14 = -3.35765e-007
16: K = -6.86618e + 000, A3 = -2.59968e-003, A4 = -8.41405e-002, A5 = 5.06798e-002, A6 = -1.06962e-002, A8 = 3.36219e-004, A10 = -3.93849e-005, A12 = 2.90683e-006, A14 = -6.28292e-008

FL 4.589
Fno 1.43
w 75.43
Ymax 3.564
BF 1.071
TL 6.247
BFa 1.034
TLa 6.209

Focusing distance INF 10cm 10cm all groups extended (comparative example)
d8 0.1370 0.1480 0.1370
d18 0.4625 0.6767 0.6844

Elem Surfs Focal Length Diameter
1 2- 3 3.7928 3.137
2 4- 5 -5.4719 2.737
3 7- 8 -21.6261 3.002
4 9-10 10.3157 3.635
5 11-12 -15.3560 4.120
6 13-14 2.3595 5.020
7 15-16 -2.4054 6.427

  FIG. 22 is an aberration diagram of Example 4 and Comparative Example 4 during focusing at infinity (spherical aberration (a), astigmatism (b), distortion (c), meridional coma (d), (e). ). FIG. 23 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), meridional coma aberration (d), (e)) at the time of focusing on a short distance object in Example 4. . FIG. 24 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), meridional coma aberration (d), (e)) at the time of short-distance object focusing in Comparative Example 4. .

  When comparing FIGS. 20 and 21, in Example 4 in which the feeding amount of the front group is larger than that of the rear group, compared to Comparative Example 4 in which all the groups are fed out, the optical path (solid line) during infinitely far focusing is The amount of fluctuation in the direction perpendicular to the optical axis of the optical path (one-dot chain line) during short-distance subject focusing is small. Therefore, fluctuations in the light incident position of each lens are suppressed regardless of the subject distance. This makes it possible to suppress aberration fluctuations, as is apparent when comparing FIGS.

(Example 5 and Comparative Example 5)
Table 5 shows lens data in Example 5 and Comparative Example 5. 25 is a sectional view of the lens of Example 5, and FIG. 26 is a sectional view of the lens of Comparative Example 5. In Example 5 and Comparative Example 5, the lens shape is common, and the lens position when focusing to infinity is also common. However, when focusing on a short-distance subject, the amount of extension in the front group and the rear group is different in Example 5, and the amount of extension in all groups is equal in Comparative Example 5. 25 and 26, a solid line indicates a lens position, an imaging surface position, and an optical path at the time of focusing on a short-distance subject (10 cm from the imaging lens), and an alternate long and short dash line indicates a lens position, an imaging surface position, and an optical path at the time of infinite distance focusing. Yes. For easy comparison, in FIGS. 20 and 21, the imaging lens side (lenses L6 to L7 in FIG. 25) is fixed and the imaging surface is relatively moved.

  The imaging lenses of Example 5 and Comparative Example 5 have an aperture stop S, a first lens L1 having a positive refractive power (lens A), and a second lens L2 having a negative refractive power (lens B) in order from the object side. The third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 (lens C) whose image side surface has an extreme value within the effective diameter. The positive refractive power of the first lens L1 is the strongest in the front group, and the seventh lens L7 has a negative refractive power in the vicinity of the optical axis and a positive refractive power in the periphery. F is a parallel plate assuming a cover glass or an IR cut filter, and I is an imaging surface of the solid-state imaging device. In Example 5, the lenses L1 to L5 constitute the front group, and the lenses L6 to L7 constitute the rear group.

[Table 5]
[Example 5]
Surface data surface number rd nd vd Effective diameter
STO INFINITY -6e-014 3.145
2 * 2.3584 0.8775 1.54470 56.2 3.145
3 * -8.7068 0.0795 2.984
4 * 3.2329 0.1902 1.63469 23.9 2.746
5 * 1.5687 0.3795 2.472
6 INFINITY 0.2348 2.470
7 * 15.8127 0.4320 1.54470 56.2 2.758
8 * 5.1333 0.0507 2.985
9 * 3.4454 0.2865 1.54470 56 3.143
10 * 11.5711 0.1000 3.327
11 * 4.6112 0.2000 1.63469 23.9 3.374
12 * 5.2562 VARIABLE 3.655
13 * -51.6053 0.9109 1.54470 56.2 3.823
14 * -2.0064 0.7278 4.397
15 * -4.3137 0.2500 1.54470 56.2 5.630
16 * 2.4134 0.5000 6.380
17 INFINITY 0.1100 1.51633 64.1 7.031
18 INFINITY VARIABLE 7.072

Aspheric coefficient
2: K = -8.61315e-001, A4 = 1.02536e-002, A6 = 9.54919e-004, A8 = -1.24245e-003, A10 = 1.47468e-003, A12 = -6.08125e-004, A14 = 9.94100 e-005
3: K = -8.00000e + 001, A4 = 5.21648e-002, A6 = -4.63698e-002, A8 = 3.11854e-002, A10 = -1.32148e-002, A12 = 3.08132e-003, A14 =- 2.91252e-004
4: K = -3.81042e + 001, A4 = 1.28097e-002, A6 = -1.49742e-002, A8 = 1.59088e-002, A10 = -8.71021e-003, A12 = 2.38371e-003, A14 =- 2.73296e-004
5: K = -7.42846e + 000, A3 = 9.90410e-003, A4 = -6.53069e-004, A5 = 1.24090e-002, A6 = 2.36058e-002, A8 = -3.47183e-002, A10 = 2.81168 e-002, A12 = -1.18281e-002, A14 = 2.12695e-003
7: K = 5.15208e + 001, A3 = -1.72409e-002, A4 = 2.55000e-002, A5 = -9.08703e-002, A6 = 8.29896e-002, A8 = -4.56691e-002, A10 = 2.20733 e-002, A12 = -6.91010e-003, A14 = 7.67117e-004
8: K = 7.75683e + 000, A3 = -5.61277e-002, A4 = -8.72367e-002, A5 = -5.80313e-003, A6 = 1.89488e-002, A8 = -1.12208e-002, A10 = 1.51008e-003, A12 = 1.05088e-003, A14 = -4.46082e-004
9: K = 1.62623e-001, A3 = -5.04031e-002, A4 = -7.07126e-002, A5 = 8.37182e-003, A6 = -1.19683e-002, A8 = -1.70341e-003, A10 = 1.37591e-003, A12 = 3.27545e-004, A14 = -7.54779e-005
10: K = 3.99231e + 001, A3 = -4.67223e-002, A4 = -6.90028e-003, A5 = 2.20342e-002, A6 = -4.40329e-002, A8 = 1.55571e-002, A10 =- 2.75737e-003, A12 = -2.08057e-004
11: K = 4.96873e + 000, A3 = -1.63028e-002, A4 = -1.97867e-001, A5 = 1.70761e-001, A6 = -9.66890e-002, A8 = 2.37360e-002, A10 =- 3.80127e-003, A12 = -9.92589e-005
12: K = 1.96649e + 000, A3 = 3.31162e-003, A4 = -1.34551e-001, A5 = 6.91107e-002, A6 = -2.04651e-002, A8 = 6.55348e-004, A10 = 8.87569e -004, A12 = -2.41822e-004, A14 = 1.40847e-005
13: K = 7.98748e + 001, A3 = -1.14749e-002, A4 = 2.33949e-002, A5 = -6.15964e-002, A6 = 3.92405e-002, A8 = -1.19550e-002, A10 = 2.59773 e-003, A12 = -2.30155e-004, A14 = -2.02946e-005
14: K = -8.75176e + 000, A3 = -2.35641e-002, A4 = -6.26544e-002, A5 = 3.57659e-002, A6 = -1.76844e-003, A8 = -3.93870e-003, A10 = 1.08225e-003, A12 = -1.29351e-004, A14 = 6.444420e-006
15: K = -3.02596e + 000, A3 = -3.46216e-002, A4 = -5.44880e-002, A5 = 1.45521e-002, A6 = 7.87924e-003, A8 = -6.49846e-004, A10 = -5.22505e-005, A12 = 8.78889e-006, A14 = -3.16845e-007
16: K = -1.22818e + 001, A3 = 5.28702e-003, A4 = -7.56527e-002, A5 = 4.70156e-002, A6 = -1.10815e-002, A8 = 3.88675e-004, A10 =- 3.77309e-005, A12 = 2.85396e-006, A14 = -6.92262e-008

FL 4.628
Fno 1.45
w 74.22
Ymax 3.564
BF 0.757
TL 6.000
BFa 0.720
TLa 5.963

Focusing distance INF 10cm 10cm all groups extended (comparative example)
d12 0.5234 0.6382 0.5234
d18 0.1471 0.3013 0.3740

Elem Surfs Focal Length Diameter
1 2- 3 3.5049 3.145
2 4- 5 -5.0243 2.746
3 7-8 -14.1561 2.985
4 9-10 8.8966 3.327
5 11-12 52.8437 3.655
6 13-14 3.8078 4.397
7 15-16 -2.8044 6.380

  FIG. 27 is an aberration diagram in Example 5 and Comparative Example 5 during focusing at infinity (spherical aberration (a), astigmatism (b), distortion (c), meridional coma (d), (e). ). FIG. 28 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), meridional coma aberration (d), (e)) at the time of focusing on a short-distance subject in Example 5. . FIG. 29 is an aberration diagram (spherical aberration (a), astigmatism (b), distortion aberration (c), meridional coma aberration (d), (e)) at the time of short-distance object focusing in Comparative Example 5. .

  When comparing FIGS. 25 and 26, in Example 5 in which the feeding amount of the front group is larger than that of the rear group, compared to Comparative Example 5 in which all the groups are fed out, the optical path (solid line) during infinitely far focusing is The amount of fluctuation in the direction perpendicular to the optical axis of the optical path (one-dot chain line) during short-distance subject focusing is small. Therefore, fluctuations in the light incident position of each lens are suppressed regardless of the subject distance. This makes it possible to suppress fluctuations in aberrations as is apparent when comparing FIGS.

  Table 6 summarizes the values of the examples corresponding to the respective conditional expressions.

[Table 6]
Example 1 Example 2 Example 3 Example 4 Example 5
(1) 1.37458 1.30901 1.26610 1.05135 1.74449
(2) 0.82925 0.83574 0.80241 0.82655 0.75738
(3) -1.22516 -1.25187 -1.35455 -1.19247 -1.08572
(4) -0.67685 -0.66759 -0.59238 -0.69314 -0.69758

  Further, the present invention is not limited to the embodiments described in the specification, and it is understood that other embodiments and modifications are included in the art from the embodiments and ideas described in the present specification. It is obvious to For example, even when a dummy lens having substantially no refractive power is further provided, it is within the scope of application of the present invention.

DESCRIPTION OF SYMBOLS 10 Imaging lens 50 Imaging unit 51 Imaging element 51a Photoelectric conversion part 52 Substrate 53 Lens barrel 53a Object side wall 54 Optical filter 55 First actuator 56 Second actuator 57 Base member 60 Input key part 70 Liquid crystal display part 71 Icon 80 Wireless communication part 92 Storage unit 100 Smartphone 101 Control unit HD1 First holder HD2 Second holder L1-L7 Lens

Claims (8)

An imaging lens having five or more lenses for forming a subject image on an imaging surface of a solid-state imaging device,
In order from the object side, it consists of a front group and a rear group,
In the front group, a lens (A) having a positive refractive power arranged on the object side and a lens (B) having a negative refractive power arranged on the image side from the lens (A) are adjacent to each other. Lined up
In the rear group, the image side surface of the lens (C) closest to the image side has an extreme value within the effective diameter,
An imaging lens, wherein a positional change amount of the front group and the rear group satisfies the following conditional expression when shooting a subject at a long distance and shooting a subject at a short distance.
1.00 <MF / MR <1.80 (1)
However, MF: Position change amount of the front group (mm)
MR: Position change amount of the rear group (mm)   The imaging lens according to claim 1, wherein the most image side lens (C) in the rear group has a negative refractive power near the optical axis and a positive refractive power around the optical axis. The positive refractive power of the lens (A) is the maximum among the positive refractive powers of the other lenses in the front group, and satisfies the following conditional expression. Imaging lens.
0.6 <fp / f <1.2 (2)
Where fp: focal length (mm) of the front lens group (A)
f: Focal length (mm) of the imaging lens when shooting a long-distance subject The imaging lens according to claim 1, wherein the lens (B) satisfies the following conditional expression.
−2.0 <fn / f <−0.8 (3)
Where fn: focal length (mm) of the front lens group (B)
f: Focal length (mm) of the imaging lens when shooting a long-distance subject The imaging lens according to claim 1, wherein the following conditional expression is satisfied.
−1.0 <fp / fn <−0.3 (4)
Where fp: focal length (mm) of the front lens group (A)
fn: focal length (mm) of the lens (B) in the front group   6. The lens according to claim 1, wherein in the front group, the lens (A) is disposed closest to the object side, and the lens (B) is disposed second from the object side. Imaging lens.   The imaging lens according to claim 1, comprising a lens having substantially no refractive power.   An imaging apparatus comprising the imaging lens according to claim 1.

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