JPWO2014103695A1 - Zoom lens and imaging device - Google Patents

Abstract

Provided are a zoom lens that achieves a zoom ratio of 30 times or more, is made compact, and has various aberrations corrected favorably, and an imaging apparatus using the zoom lens. In a zoom lens having five lens groups, during zooming, the respective lens groups from the first lens group to the fourth lens group move, and the fifth lens group does not move during zooming or focusing, The following conditional expression is satisfied. 1.90 <(β2T / β2W) / (β3T / β3W) <3.40 (1) 3.00 <f3 / fw <4.50 (2) where β2W: lateral magnification at the wide angle end of the second lens group β2T: Lateral magnification at the telephoto end of the second lens group β3W: Lateral magnification at the wide-angle end of the third lens group β3T: Lateral magnification at the telephoto end of the third lens group f3: Focal length (mm) fw of the third lens group Focal length of the entire system at the wide angle end (mm)

Description

  The present invention relates to a zoom lens and an image pickup apparatus. For example, the present invention is used in an optical unit for capturing a still image or a moving image of a subject with a solid-state image pickup device. The present invention relates to a zoom lens having a wide angle of field of view and an imaging device including the zoom lens.

  In recent years, digital still cameras and video cameras using solid-state imaging devices such as CCD (Charge Coupled Device) type image sensors or CMOS (Complementary Metal Oxide Semiconductor) type image sensors have become more compact and highly variable, such as being smaller and thinner. There is an increasing demand for zoom lenses that can achieve double magnification.

  As measures for these demands, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a positive lens A zoom lens which has a fourth lens group having a refractive power and achieves a high zoom ratio is proposed in Patent Document 1. Further, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a first lens group having a negative refractive power. Patent Documents 2 and 3 propose a zoom lens in which four lens groups and a fifth lens group having a positive refractive power are arranged to achieve a high zoom ratio.

JP 2011-28238 JP JP 2011-232542 JP 2012-159579 A

  However, the zoom lens described in Patent Document 1 has a problem that the zoom ratio is as small as 9 to 12 times and the total length at the telephoto end is large. When the total length is large, it is disadvantageous for making the lens barrel compact, particularly thin. In addition, since the final lens group is movable at the time of zooming, if the total length is shortened, when the distance between the final lens group and the solid-state image sensor approaches, the captured image is easily affected by dust and scratches on the final lens group. In other words, the zoom type of the four-group configuration in which the first group is positive, the second group is negative, the third group is positive, and the fourth group is positive (hereinafter referred to as positive, negative, positive) is a compact and high zoom ratio. It can be said that coexistence is difficult.

  On the other hand, in the zoom lenses described in Patent Documents 2 and 3, the zoom ratio is 10 to 23 times, which is higher than that of Patent Document 1, but in recent years, higher zoom ratios have been achieved. There is a fact that there is a need to make it.

  The present invention has been made in view of such problems, and a zoom lens that achieves a zoom ratio of 30 times or more, is compact, and has various aberrations corrected satisfactorily, and the zoom lens. The object is to provide an imaging device.

The zoom lens according to claim 1 is a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens having a positive refractive power, which are arranged in order from the object side. In a zoom lens that includes a lens group, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power, and performs zooming by changing the interval between the lens groups,
At the time of zooming, the respective lens groups from the first lens group to the fourth lens group move, and the fifth lens group does not move at the time of zooming or focusing, and satisfies the following conditional expression: It is characterized by that.
1.90 <(β2T / β2W) / (β3T / β3W) <3.40 (1)
3.00 <f3 / fw <4.50 (2)
However,
β2W: Lateral magnification at the wide-angle end of the second lens group β2T: Lateral magnification at the telephoto end of the second lens group β3W: Lateral magnification at the wide-angle end of the third lens group β3T: Telephoto end of the third lens group Lateral magnification f3: focal length (mm) of the third lens group
fw: focal length of the entire system at the wide-angle end (mm)

  The zoom lens according to the present invention includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, arranged in order from the object side, It is composed of five lens groups, a fourth lens group having refractive power and a fifth lens having positive refractive power. With this configuration, there are two groups having negative refractive power, so the refractive power configuration of the entire lens system becomes symmetrical, and various aberrations such as coma, distortion, and lateral chromatic aberration are applied. It is possible to correct effectively by the symmetrical arrangement.

  In addition, the fourth lens group is moved from the first lens group, and the focal position change correction associated with zooming and zooming is performed, thereby achieving a zoom lens that is compact in both length and front lens diameter.

  The fifth lens group is the lens group closest to the solid-state image sensor. If the fifth lens group is configured to move during zooming and focusing, the distance from the solid-state image sensor approaches and the captured image becomes the fifth. There is a risk of being easily affected by dust and scratches on the lens group. In particular, in a miniaturized zoom lens, since the distance between the final lens and the solid-state image sensor is closer, the tendency is prominent. Therefore, in the present invention, by fixing the fifth lens group without moving in the optical axis direction, it becomes possible to seal the space between the final lens and the solid-state imaging device, thereby preventing dust and scratches. The influence can be suppressed.

Conditional expression (1) is an expression that prescribes the variable magnification burden of the second lens group and the third lens group. If the value of conditional expression (1) is less than the upper limit, the variable magnification load of the second lens group does not become too large, and the difference in the incident angle when the entire luminous flux around the screen enters the lens surface in the second lens group is a wide angle. Small at the end and at the telephoto end. Therefore, the field curvature change due to zooming does not become too large, and the field curvature can be corrected well over the entire zoom range. On the other hand, if the value of conditional expression (1) exceeds the lower limit, the zooming burden of the third lens group does not become too large, and it is not necessary to set the refractive power of the third lens group to be large. Thereby, since the radius of curvature of each lens surface in the third lens group does not become too small, coma can be corrected well over the entire zoom range.
It is more preferable that the following conditional expression (1) ′ is satisfied.
2.0 ≦ (β2T / β2W) / (β3T / β3W) ≦ 2.90 (1) ′

Conditional expression (2) defines the refractive power of the third lens group. If the value of conditional expression (2) is less than the upper limit, the refractive power of the third lens group will not be too small, and the refractive power of the second lens group will not be too strong to secure the zoom ratio. It is possible to correct spherical aberration at a good level. On the other hand, when the value of conditional expression (2) exceeds the lower limit, the refractive power of the third lens group does not become too strong, and it becomes possible to correct coma at the telephoto end.
It is more preferable that the following conditional expression (2) ′ is satisfied.
3.20 ≦ f3 / fw ≦ 4.30 (2) ′

The zoom lens according to claim 2 is characterized in that, in the invention according to claim 1, the following conditional expression is satisfied.
7.0 <| f1 / f2 | <12.0 (3)
However,
f1: Focal length (mm) of the first lens group
f2: Focal length (mm) of the second lens group

Conditional expression (3) defines the ratio of the focal lengths of the first lens group and the second lens group. When the value of conditional expression (3) exceeds the lower limit value, the refractive power of the first lens group does not become too strong, and it is possible to correct field curvature and lateral chromatic aberration at the telephoto end. On the other hand, if the upper limit of conditional expression (3) is not reached, the refractive power of the second lens group will not be too strong, and it will be possible to satisfactorily correct off-axis aberration fluctuations, particularly distortion and astigmatism associated with zooming. .
It is more preferable that the following conditional expression (3) ′ is satisfied.
7.5 ≦ | f1 / f2 | ≦ 10.0 (3) ′

A zoom lens according to a third aspect of the present invention is the zoom lens according to the first or second aspect, wherein the first lens group is a first lens having a negative refractive power arranged in order from the object side, a positive lens It has a first lens 1-2 having a refractive power and a first-3 lens having a positive refractive power, and at least one of the lenses having a positive refractive power satisfies the following conditional expression: .
ν1P> 75 (4)
However,
ν1P: Abbe number of at least one lens having positive refractive power in the first lens group

  The first lens group includes, in order from the object side, a 1-1 lens having a negative refractive power, a 1-2 lens having a positive refractive power, and a 1-3 lens having a positive refractive power. By adopting such a configuration, the principal point position of the first lens group is located on the second lens group side, and the principal point interval between the first lens and the second lens group at the wide angle end is made short. Therefore, the size of the first lens is reduced.

Conditional expression (4) is an expression that prescribes the Abbe number of lenses having positive refractive power constituting the first lens group. By including a lens having a negative refractive power in the first lens group having a positive refractive index as a whole and a lens having a positive refractive power using a glass material that satisfies the conditional expression (4), The secondary spectrum can be removed, and the longitudinal chromatic aberration generated near the telephoto end can be reduced. If the Abbe number is increased so as to exceed the lower limit of the conditional expression (4), the correction of chromatic aberration near the telephoto end is improved.
It is more preferable that the following conditional expression (4) ′ is satisfied.
ν1P ≧ 80 (4) ′

  A zoom lens according to a fourth aspect of the present invention is the zoom lens according to any one of the first to third aspects, wherein the third lens group is a third lens having a positive refractive power arranged in order from the object side. , A 3-2 lens having a positive refractive power, a 3-3 lens having a negative refractive power, and a 3-4 lens having a positive refractive power, of which the 3-2 lens and the The 3rd-3 lens is cemented.

  The third lens group includes, in order from the object side, a 3-1 lens having a positive refractive index, a 3-2 lens having a positive refractive index, a 3-3 lens having a negative refractive index, It is composed of a 3-4 lens having a positive refractive index, and among these, the 3-2 lens and the 3-3 lens are cemented. The conventional third lens group is often composed of three elements such as an arrangement of a positive single lens and a pair of positive and negative cemented lenses and a positive and negative triplet type. However, when a zoom lens having a high zoom ratio is used, the three-lens configuration has insufficient aberration correction power and may cause many off-axis aberrations such as coma. Therefore, in the present invention, by adding another positive single lens to the image side of the positive single lens and one pair of positive and negative cemented lenses, generation of off-axis aberration is suppressed, and good optical performance is obtained. Can be done.

A zoom lens according to a fifth aspect of the present invention is the zoom lens according to any one of the first to fourth aspects, wherein the third lens group moves in a direction perpendicular to the optical axis, thereby blurring an image on the image plane. It is a camera shake correction group that optically corrects.

  By moving the third lens group in the direction perpendicular to the optical axis, it is possible to correct blurring of the captured image when the entire zoom lens is tilted. By moving the entire third lens group, it is possible to suppress the occurrence of chromatic aberration due to decentering during image stabilization, and good optical performance can be obtained even when large camera shake occurs.

  A zoom lens according to a sixth aspect of the present invention is the zoom lens according to any one of the first to fifth aspects, wherein the fourth lens group is composed of one negative lens.

  Since the fourth lens group is disposed at a position where the axial ray height is low, the amount of spherical aberration and coma generated tends to be relatively small. Therefore, the configuration can be made with only one single lens, and the cost can be reduced.

  A zoom lens according to a seventh aspect is characterized in that, in the invention according to any one of the first to sixth aspects, focusing is performed by moving the fourth lens group in an optical axis direction.

  It is desirable to perform focusing by moving the fourth lens along the optical axis. Since the fourth lens can be composed of a single lens, it is lightweight, and when used as a focus group, there are advantages in terms of miniaturization of the actuator to be driven and power consumption.

A zoom lens according to an eighth aspect of the present invention is the zoom lens according to any one of the first to seventh aspects, wherein the fourth lens group satisfies the following conditional expression.
3.8 <| f4 / fw | <6.0 (5)
However,
f4: Focal length (mm) of the fourth lens group
fw: focal length of the entire system at the wide-angle end (mm)

Conditional expression (5) defines the refractive power of the fourth lens group. If the value of conditional expression (5) exceeds the lower limit value, the power of the fourth lens group does not become too weak, and it is possible to avoid an increase in the size of the optical system. On the other hand, if the value of the conditional expression (5) is less than the upper limit, the effect of downsizing the optical system is diminished, but the power of the fourth lens group does not become too strong, and balance with aberrations occurring in other lens groups. Can be kept.
It is more preferable that the following conditional expression (5) ′ is satisfied.
4.0 ≦ | f4 / fw | ≦ 5.2 (5) ′

  A zoom lens according to a ninth aspect of the present invention is the zoom lens according to any one of the first to eighth aspects, wherein the second lens group is a 2-1 lens having a negative refractive power arranged in order from the object side. And a second lens having a negative refractive power and a second lens having a positive refractive power.

  The second lens group is a second lens having a negative refractive power, a second lens having a negative refractive power, a second lens having a positive refractive power, and a second lens having a positive refractive power, which are arranged in order from the object side. It is configured. By disposing two negative lenses, such as a 2-1 lens having negative refractive power on the object side and a 2-2 lens having negative refractive power, the first lens having a large diameter is arranged at a large angle. The incident light beam can be relaxed quickly, and field curvature and distortion can be effectively corrected. Furthermore, by arranging the second and third lenses having positive refractive power on the image side, it is possible to effectively correct the lateral chromatic aberration at the wide angle end and the axial chromatic aberration at the telephoto end.

A zoom lens according to a tenth aspect is characterized in that, in the invention according to any one of the first to ninth aspects, the following conditional expression is satisfied.
0.01 <| f2 / ft | <0.15 (6)
However,
f1: Focal length (mm) of the second lens group
ft: focal length of the entire system at the telephoto end (mm)

Conditional expression (6) defines the refractive power of the second lens group. When the value of conditional expression (6) exceeds the lower limit value, the focal length of the second lens group does not become too small, the Petzval sum does not become too large in the negative direction, and the field curvature becomes small. On the other hand, when the value of conditional expression (6) is less than the upper limit, the amount of movement during zooming of the second lens does not become too large when zooming in high, and the total lens length at the telephoto end increases. Never too much.
It is more preferable that the following conditional expression (6) ′ is satisfied.
0.03 ≦ | f2 / ft | ≦ 0.08 (6) ′

  A zoom lens according to an eleventh aspect is characterized in that, in the invention according to any one of the first to tenth aspects, the fifth lens group is constituted by a single lens.

  Since the fifth lens is disposed at a position where the axial ray height is low, the generation amount of spherical aberration and coma aberration is relatively small. Therefore, a configuration with only one single lens is possible. It is desirable to configure the fifth lens group with a single positive lens in order to achieve cost reduction and downsizing of the optical system.

  A zoom lens according to a twelfth aspect is characterized in that in the invention according to any one of the first to eleventh aspects, the lens has substantially no refractive power. Such a zoom lens is also within the scope of the present invention.

  An image pickup apparatus according to a thirteenth aspect includes the zoom lens according to any one of the first to twelfth aspects and a solid-state image pickup device that photoelectrically converts an image formed by the zoom lens.

  According to the present invention, it is possible to provide a zoom lens that achieves a zoom ratio of 30 times or more, is made compact, and has various aberrations corrected favorably, and an imaging apparatus using the zoom lens.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an external view of a digital camera that is an example of an imaging apparatus including a zoom lens according to the present embodiment, in which (a) is a front view of the digital camera and (b) is a rear view. 2A and 2B are cross-sectional views of the zoom lens according to the first exemplary embodiment, in which FIG. 1A is a cross-sectional view at a wide-angle end, FIG. 2B is a cross-sectional view at an intermediate position, and FIG. FIG. 4 is an aberration diagram (spherical aberration, astigmatism, distortion) of the zoom lens of Example 1, (a) is an aberration diagram at the wide-angle end, (b) is an aberration diagram at the middle, and (c) is an aberration at the telephoto end. FIG. FIG. 4 is a cross-sectional view of a zoom lens according to a second embodiment, where (a) is a cross-sectional view at the wide-angle end, (b) is a cross-sectional view at the middle, and (c) is a cross-sectional view at the telephoto end. FIG. 4 is aberration diagrams (spherical aberration, astigmatism, distortion) of the zoom lens of Example 2, (a) is an aberration diagram at the wide-angle end, (b) is an aberration diagram at the middle, and (c) is an aberration at the telephoto end. FIG. FIG. 4 is a cross-sectional view of a zoom lens according to Embodiment 3, where (a) is a cross-sectional view at the wide angle end, (b) is a cross-sectional view at the middle, and (c) is a cross-sectional view at the telephoto end. FIG. 4 is an aberration diagram (spherical aberration, astigmatism, distortion) of the zoom lens of Example 3, (a) is an aberration diagram at the wide angle end, (b) is an aberration diagram at the middle, and (c) is an aberration at the telephoto end. FIG. FIG. 4 is a cross-sectional view of a zoom lens according to a fourth exemplary embodiment, where (a) is a cross-sectional view at the wide-angle end, (b) is a cross-sectional view at the middle, and (c) is a cross-sectional view at the telephoto end. FIG. 7A is an aberration diagram (spherical aberration, astigmatism, distortion) of the zoom lens of Example 4; (a) is an aberration diagram at the wide-angle end; (b) is an aberration diagram at the middle; and (c) is an aberration at the telephoto end. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an external view of a digital camera that is an example of an imaging apparatus including a zoom lens according to the present embodiment. FIG. 1A is a front view of the digital camera 1, and FIG. 1B is a rear view.

  As shown in FIG. 2, the digital camera 1 includes a lens barrel that holds a zoom lens, an imaging unit 2 having an imaging element, and a camera body unit 3.

  The imaging unit 2 includes a lens barrel that holds a zoom lens capable of zooming operation and a solid-state imaging device such as a CCD or a CMOS as shown in the embodiments described later, and forms an image via the zoom lens in the lens barrel. The subject image thus converted is converted into an image signal by a solid-state imaging device.

  The camera body unit 3 includes an LCD display unit 6 including an LCD (Liquid Crystal Display), an EVF (Electronic View Finder) 7, and external connection terminals for connecting the digital camera 1 to a personal computer (not shown). The image signal captured by the imaging unit 2 is subjected to predetermined signal processing, image display on the LCD display unit 6 and EVF 7, image recording on a recording medium such as a memory card (not shown), or a personal computer Processing such as transferring an image to.

  On the front surface of the camera body 3, a flash light emitting unit 4 is provided at an appropriate upper position. Further, an LCD display unit 6 and an EVF 7 are provided on the back side of the camera body unit 3 for displaying captured images and reproducing and displaying recorded images.

  On the upper surface of the camera body 3, there are provided a shutter button 5 and a shooting mode changeover switch (not shown) that switches between “recording mode” and “reproduction mode” near the shutter button 5. The recording mode is a mode for taking a picture from the shooting standby state through the exposure control process, and the playback mode is a mode for reproducing and displaying the shot image recorded on the memory card on the LCD display unit 6 and the EVF 7. is there.

  On the back surface of the camera body 3, a playback frame advance switch / zoom switch 9 is provided for frame playback of playback images and zoom operations during shooting. The frame advance of the playback image by the playback frame advance switch / zoom switch 9 is a mode in which the camera is set to the playback mode and the images recorded on the memory card 13 are sequentially displayed on the LCD display unit 6 together with the frame number. . Note that it is possible to instruct to change the image display on the LCD display unit 6 in the ascending order direction (direction of photographing order) or the descending order direction (direction opposite to the photographing order). The zoom operation at the time of shooting is performed by operating the playback frame advance switch / zoom switch 9 to change the zoom lens in the tele direction or the wide direction.

  Further, an EVF changeover switch 8 for selecting an LCD display unit 6 and an EVF 7 for displaying an image is provided on the back surface of the camera body unit 3.

  In addition, a battery (not shown) as a power source for operating the digital camera 1 is provided inside the bottom surface of the camera body 3.

(Example)
Next, examples of the zoom lens suitable for the above-described embodiment will be described. However, the present invention is not limited to the following examples. Symbols used in each example are as follows.
f: Focal length (mm) of the entire imaging lens system
Fno: F number 2Y: diagonal length of imaging surface of solid-state imaging device (mm)
R: radius of curvature (mm)
D: Shaft upper surface distance (mm)
Nd: Refractive index with respect to d-line of lens material νd: Abbe number of lens material

  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 represented by the following “Equation 1”.

但し、
Ａｉ：ｉ次の非球面係数
Ｒ ：曲率半径
Ｋ ：円錐定数

However,
Ai: i-order aspheric coefficient R: radius of curvature K: conic constant

Example 1
Table 1 shows lens data of Example 1. 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-02). 4 is a cross-sectional view of the imaging lens of Example 1. FIG.

(Table 1)
Example 1

f = 4.10-23.24-139.41
Fno = 3.04-4.95-6.09
Zoom ratio = 34.0

Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 60.403 1.700 1.90370 31.3 17.75
2 36.825 4.690 1.49700 81.6 16.17
3 345.746 0.200 15.96
4 38.281 3.715 1.58910 61.3 15.65
5 159.724 d1 15.43
6 126.496 0.800 1.91080 35.3 9.21
7 8.671 5.580 6.87
8 -18.228 0.700 1.48750 70.4 6.72
9 13.454 2.535 1.92290 20.9 6.82
10 59.019 d2 6.70
11 (Aperture) ∞ 0.620 3.64
12 * 15.625 2.035 1.69350 53.2 3.82
13 * -31.735 1.295 3.85
14 11.472 2.990 1.48750 70.4 3.66
15 -30.261 0.965 1.90370 31.3 3.31
16 11.057 0.660 3.15
17 34.698 1.555 1.49700 81.6 3.18
18 -15.223 d3 3.20
19 * 105.000 1.100 1.54470 56.2 3.07
20 * 10.055 d4 2.99
21 * 106.000 3.770 1.54470 56.2 5.80
22 * -10.295 1.057 4.88
23 ∞ 0.300 1.52310 54.4 4.58
24 ∞ 3.830 4.55
25 ∞ 0.500 1.51680 64.2 3.98
26 ∞ 0.370 3.93

Aspheric coefficient

Surface 12 Surface 20
K = -0.17400E + 01 K = 0.00000E + 00
A4 = -0.48364E-04 A4 = 0.22309E-03
A6 = -0.99412E-05 A6 = 0.18532E-03
A8 = 0.26178E-06 A8 = -0.28544E-04
A10 = -0.10520E-07 A10 = 0.14473E-05

Side 13 Side 21
K = 0.00000E + 00 K = 0.00000E + 00
A4 = -0.43199E-04 A4 = 0.26754E-03
A6 = -0.10917E-04 A6 = 0.10252E-04
A8 = 0.32197E-06 A8 = -0.23897E-06
A10 = -0.11353E-07 A10 = 0.19391E-08

19th page 22nd page
K = 0.00000E + 00 K = 0.00000E + 00
A4 = -0.23121E-04 A4 = 0.38959E-03
A6 = 0.12091E-03 A6 = 0.53157E-05
A8 = -0.19058E-04 A8 = -0.35990E-07
A10 = 0.95342E-06 A10 = -0.56749E-09

Focal length of each position, F number, between groups

f Fno angle of view 2Y d1 d2 d3 d4
4.10 3.04 86.9 6.46 0.576 43.829 2.700 4.325
23.24 4.95 19 7.71 26.429 14.741 7.787 11.491
139.41 6.09 3.2 7.716 48.504 1.150 12.489 13.094

Lens group data

Lens group Start surface Focal length (mm)
1 1 70.39
2 6 -8.80
3 11 14.63
4 19 -20.50
5 21 17.43

  2 is a cross-sectional view of the zoom lens of Example 1, FIG. 2 (a) is a cross-sectional view at the wide-angle end, FIG. 2 (b) is a cross-sectional view at the middle, and FIG. 2 (c) is the telephoto end. FIG. In the figure, Gr1 is a first lens group having a positive refractive power, Gr2 is a second lens group having a negative refractive power, Gr3 is a third lens group having a positive refractive power, and Gr4 is a first lens group having a negative refractive power. 4 lens group, Gr5 is a fifth lens group having positive refractive power, L1 is a first lens, L2 is a second lens, L3 is a third lens, L4 is a fourth lens, L5 is a fifth lens, and L6 is a fifth lens 6 lenses, L7 is the 7th lens, L8 is the 8th lens, L9 is the 9th lens, L10 is the 10th lens, L11 is the 11th lens, L12 is the 12th lens, S is the aperture stop, I is the imaging surface . Further, F1 and F2 indicate parallel flat plates assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, and the like. The first lens L1 is a 1-1 lens having a negative refractive power, the second lens L2 is a 1-2 lens having a positive refractive power, and the third lens is a first lens having a positive refractive power. -3 lens. The fourth lens L4 is a 2-1 lens having a negative refractive power, the fifth lens L5 is a 2-2 lens having a negative refractive power, and the sixth lens L6 has a positive refractive power. It is the 2nd-3 lens which has. Furthermore, the seventh lens L7 is a 3-1 lens having a positive refractive power, the eighth lens L8 is a third-2 lens having a positive refractive power, and the ninth lens L9 has a negative refractive power. The tenth lens L10 is a third lens having a positive refractive power, and the eighth lens L8 and the ninth lens L9 are cemented. The fourth lens group Gr4 and the fifth lens group GR5 are each composed of a single lens.

  FIG. 3 is an aberration diagram (spherical aberration, astigmatism, distortion) of the zoom lens of Example 1. Here, FIG. 3A is an aberration diagram at the wide-angle end. FIG. 3B is an aberration diagram in the middle. FIG. 3C is an aberration diagram at the telephoto end. In the spherical aberration diagram, the dotted line represents the amount of spherical aberration with respect to the g line, and the solid line represents the amount of spherical aberration with respect to the d line. In the astigmatism diagram, the solid line S represents the sagittal plane, and the dotted line M represents the meridional plane (the same applies hereinafter).

In the zoom lens of Example 1, during zooming, the first lens group Gr1, the second lens group Gr2, the third lens group Gr3, and the fourth lens group Gr4 move along the optical axis direction, and the intervals between the lens groups. It is possible to change the magnification by changing. The fifth lens group Gr5 is fixed.
Further, by moving the fourth lens group Gr4, focusing in a range from infinity to a finite distance can be performed. It is assumed that the seventh lens L7 is a glass mold lens, the eleventh lens L11 and the twelfth lens L12 are plastic lenses, and the other lenses are polished lenses made of a glass material. The eleventh lens L11 and the twelfth lens L12 are lenses arranged relatively on the image side, and since the light flux passing through the lens is also thin, the influence on the optical performance due to temperature change is small, so a plastic lens is used. By doing so, the cost can be reduced. Moreover, since the plastic lens by injection molding can easily manufacture an aspherical lens, each aspherical lens can effectively correct each aberration such as field curvature and distortion.

(Example 2)
Table 2 shows lens data of Example 2.

(Table 2)
Example 2

f = 4.41-25.00-132.33
Fno = 3.29-5.25-6.08
Zoom ratio = 30.0

Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 62.646 1.500 1.90370 31.3 16.70
2 37.661 4.500 1.49700 81.6 16.27
3 343.135 0.200 16.20
4 39.208 3.710 1.62041 60.3 16.00
5 155.568 d1 15.78
6 579.307 0.800 1.95375 32.3 8.05
7 9.153 4.889 6.39
8 -17.370 0.700 1.48750 70.4 6.25
9 14.023 2.658 1.92290 20.9 6.40
10 114.604 d2 6.30
11 (Aperture) ∞ 0.620 3.43
12 * 15.678 2.035 1.69350 53.2 3.60
13 * -35.208 1.653 3.62
14 12.141 2.830 1.48750 70.4 3.47
15 -34.449 2.000 1.90370 31.3 3.19
16 10.457 0.660 2.98
17 21.034 1.550 1.49700 81.6 3.03
18 -15.312 d3 3.06
19 * 1000.000 1.000 1.54470 56.2 2.95
20 * 9.846 d4 2.90
21 * 87.163 3.810 1.54470 56.2 5.80
22 * -9.757 1.057 4.87
23 ∞ 0.300 1.52310 54.4 4.58
24 ∞ 3.830 4.55
25 ∞ 0.500 1.51680 64.2 4.01
26 ∞ 0.370 3.96

Aspheric coefficient

Surface 12 Surface 20
K = 0.00000E + 00 K = 0.00000E + 00
A4 = -0.11929E-04 A4 = -0.26532E-03
A6 = -0.33487E-04 A6 = 0.23591E-03
A8 = 0.48919E-05 A8 = -0.30144E-04
A10 = -0.33194E-06 A10 = 0.14179E-05
A12 = 0.80529E-08

Side 13 Side 21
K = 0.00000E + 00 K = 0.00000E + 00
A4 = 0.54509E-04 A4 = 0.23947E-03
A6 = -0.36133E-04 A6 = 0.95083E-05
A8 = 0.53434E-05 A8 = -0.19630E-06
A10 = -0.36712E-06 A10 = 0.18544E-08
A12 = 0.90422E-08

19th page 22nd page
K = 0.00000E + 00 K = 0.00000E + 00
A4 = -0.37917E-03 A4 = 0.50000E-03
A6 = 0.16311E-03 A6 = -0.50372E-06
A8 = -0.20399E-04 A8 = 0.12529E-06
A10 = 0.93808E-06 A10 = -0.14867E-08

Focal length of each position, F number, between groups

f Fno angle of view 2Y d1 d2 d3 d4
4.41 3.29 82.8 6.46 0.550 41.866 2.700 4.033
25.00 5.25 17.7 7.788 27.988 13.805 8.086 10.320
132.33 6.08 3.4 7.8 49.638 1.150 10.993 11.794

Lens group data

Lens group Start surface Focal length (mm)
1 1 71.13
2 6 -9.12
3 11 14.63
4 19 -18.26
5 21 16.34

  4 is a cross-sectional view of the zoom lens of Example 2, FIG. 4 (a) is a cross-sectional view at the wide-angle end, FIG. 4 (b) is a cross-sectional view at the middle, and FIG. 4 (c) is the telephoto end. FIG. In the figure, Gr1 is a first lens group having a positive refractive power, Gr2 is a second lens group having a negative refractive power, Gr3 is a third lens group having a positive refractive power, and Gr4 is a first lens group having a negative refractive power. 4 lens group, Gr5 is a fifth lens group having positive refractive power, L1 is a first lens, L2 is a second lens, L3 is a third lens, L4 is a fourth lens, L5 is a fifth lens, and L6 is a fifth lens 6 lenses, L7 is the 7th lens, L8 is the 8th lens, L9 is the 9th lens, L10 is the 10th lens, L11 is the 11th lens, L12 is the 12th lens, S is the aperture stop, I is the imaging surface . Further, F1 and F2 indicate parallel flat plates assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state imaging device, and the like. The first lens L1 is a 1-1 lens having a negative refractive power, the second lens L2 is a 1-2 lens having a positive refractive power, and the third lens is a first lens having a positive refractive power. -3 lens. The fourth lens L4 is a 2-1 lens having a negative refractive power, the fifth lens L5 is a 2-2 lens having a negative refractive power, and the sixth lens L6 has a positive refractive power. It is the 2nd-3 lens which has. Furthermore, the seventh lens L7 is a 3-1 lens having a positive refractive power, the eighth lens L8 is a third-2 lens having a positive refractive power, and the ninth lens L9 has a negative refractive power. The tenth lens L10 is a third lens having a positive refractive power, and the eighth lens L8 and the ninth lens L9 are cemented. The eleventh lens L11 is a single negative lens. The fourth lens group Gr4 and the fifth lens group GR5 are each composed of a single lens.

  FIG. 5 is an aberration diagram (spherical aberration, astigmatism, distortion) of the zoom lens of Example 2. Here, FIG. 5A is an aberration diagram at the wide-angle end. FIG. 5B is an aberration diagram in the middle. FIG. 5C is an aberration diagram at the telephoto end.

In the zoom lens of Example 2, when zooming, the first lens group Gr1, the second lens group Gr2, the third lens group Gr3, and the fourth lens group Gr4 move along the optical axis direction, and the intervals between the lens groups. It is possible to change the magnification by changing. The fifth lens group Gr5 is fixed.
Further, by moving the fourth lens group Gr4, focusing in a range from infinity to a finite distance can be performed. It is assumed that the seventh lens L7 is a glass mold lens, the eleventh lens L11 and the twelfth lens L12 are plastic lenses, and the other lenses are polished lenses made of a glass material.

(Example 3)
Table 3 shows lens data of Example 3.

(Table 3)
Example 3

f = 4.10-25.93-164
Fno = 3.39-5.63-6.09
Zoom ratio = 40.0

Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 73.296 1.700 1.88300 40.8 21.80
2 40.977 6.474 1.49700 81.6 18.68
3 2062.174 0.200 17.44
4 39.118 4.999 1.49700 81.6 16.00
5 155.256 0.500 15.59
6 137.739 0.800 1.90366 31.3 10.71
7 9.801 6.845 7.95
8 -18.662 0.700 1.48750 70.4 7.81
9 16.213 3.031 1.92290 20.9 8.09
10 110.762 61.208 8.00
11 (Aperture) ∞ 0.500 3.76
12 * 13.760 2.035 1.69350 53.2 3.92
13 * -51.637 2.496 3.89
14 16.056 1.552 1.48750 70.4 3.58
15 -82.464 0.964 1.90370 31.3 3.43
16 10.917 0.660 3.28
17 21.988 2.400 1.49700 81.6 3.32
18 -18.666 4.827 3.35
19 * 800.000 2.129 1.54470 56.2 3.08
20 * 9.369 4.660 2.98
21 * 106.000 3.021 1.54470 56.2 5.70
22 * -8.698 2.000 4.84
23 ∞ 0.300 1.52310 54.4 4.39
24 ∞ 2.000 4.37
25 ∞ 0.500 1.51680 64.2 4.08
26 ∞ 0.370 4.04

Aspheric coefficient

Surface 12 Surface 20
K = 0.00000E + 00 K = 0.00000E + 00
A4 = -0.21253E-04 A4 = -0.55144E-03
A6 = -0.25495E-04 A6 = 0.16019E-03
A8 = 0.31974E-05 A8 = -0.15749E-04
A10 = -0.18579E-06 A10 = 0.63676E-06
A12 = 0.37546E-08

Side 13 Side 21
K = 0.00000E + 00 K = 0.00000E + 00
A4 = 0.52264E-04 A4 = -0.85893E-04
A6 = -0.29299E-04 A6 = 0.14012E-04
A8 = 0.38399E-05 A8 = -0.17880E-06
A10 = -0.23177E-06 A10 = 0.94970E-09
A12 = 0.49031E-08

19th page 22nd page
K = 0.00000E + 00 K = 0.00000E + 00
A4 = -0.40111E-03 A4 = 0.50000E-03
A6 = 0.82201E-04 A6 = -0.38358E-05
A8 = -0.73160E-05 A8 = 0.28582E-06
A10 = 0.26878E-06 A10 = -0.33323E-08

Focal length of each position, F number, between groups

f Fno angle of view 2Y d1 d2 d3 d4
4.10 3.39 86.9 6.46 0.500 61.208 4.827 4.66
25.93 5.63 17.0 7.9 29.280 16.592 12.362 10.386
164.00 6.09 2.7 7.948 59.483 1.200 14.343 11.013

Lens group data

Lens group Start surface Focal length (mm)
1 1 83.77
2 6 -10.27
3 11 17.05
4 19 -17.42
5 21 14.90

  6A and 6B are cross-sectional views of the zoom lens according to the third exemplary embodiment. FIG. 6A is a cross-sectional view at the wide-angle end, FIG. 6B is a cross-sectional view at the middle, and FIG. FIG. In the figure, Gr1 is a first lens group having a positive refractive power, Gr2 is a second lens group having a negative refractive power, Gr3 is a third lens group having a positive refractive power, and Gr4 is a first lens group having a negative refractive power. 4 lens group, Gr5 is a fifth lens group having positive refractive power, L1 is a first lens, L2 is a second lens, L3 is a third lens, L4 is a fourth lens, L5 is a fifth lens, and L6 is a fifth lens 6 lenses, L7 is the 7th lens, L8 is the 8th lens, L9 is the 9th lens, L10 is the 10th lens, L11 is the 11th lens, L12 is the 12th lens, S is the aperture stop, I is the imaging surface . F denotes a parallel plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state image sensor, or the like. The first lens L1 is a 1-1 lens having a negative refractive power, the second lens L2 is a 1-2 lens having a positive refractive power, and the third lens is a first lens having a positive refractive power. -3 lens. The fourth lens L4 is a 2-1 lens having a negative refractive power, the fifth lens L5 is a 2-2 lens having a negative refractive power, and the sixth lens L6 has a positive refractive power. It is the 2nd-3 lens which has. Furthermore, the seventh lens L7 is a 3-1 lens having a positive refractive power, the eighth lens L8 is a third-2 lens having a positive refractive power, and the ninth lens L9 has a negative refractive power. The tenth lens L10 is a third lens having a positive refractive power, and the eighth lens L8 and the ninth lens L9 are cemented. The eleventh lens L11 is a single negative lens. The fourth lens group Gr4 and the fifth lens group GR5 are each composed of a single lens.

  FIG. 7 is an aberration diagram (spherical aberration, astigmatism, distortion) of the zoom lens of Example 3. Here, FIG. 7A is an aberration diagram at the wide-angle end. FIG. 7B is an aberration diagram in the middle. FIG. 7C is an aberration diagram at the telephoto end.

In the zoom lens of Example 3, during zooming, the first lens group Gr1, the second lens group Gr2, the third lens group Gr3, and the fourth lens group Gr4 move along the optical axis direction, and the intervals between the lens groups. It is possible to change the magnification by changing. The fifth lens group Gr5 is fixed.
Further, by moving the fourth lens group Gr4, focusing from the infinity range to the finite distance range can be performed. It is assumed that the seventh lens L7 and the eleventh lens L11 are glass mold lenses, the twelfth lens L12 is a plastic lens, and the other lenses are polished lenses made of a glass material.

Example 4
Table 4 shows lens data of Example 4.

(Table 4)
Example 4

f = 4.10-27.47-184.48
Fno = 3.28-5.56-6.97
Zoom ratio = 45

Surface number R (mm) D (mm) Nd νd Effective radius (mm)
1 75.926 1.700 1.88300 40.8 20.88
2 47.704 6.000 1.43700 95.1 19.37
3 5879.798 0.200 19.17
4 45.704 5.000 1.49700 81.6 18.90
5 148.226 d1 18.52
6 117.289 0.800 1.90366 31.3 10.42
7 9.985 6.812 7.90
8 -18.419 0.700 1.48750 70.4 7.72
9 16.629 2.675 1.92290 20.9 7.97
10 130.552 d2 7.90
11 (Aperture) ∞ 0.620 3.70
12 * 13.543 2.066 1.69350 53.2 3.87
13 * -49.097 0.928 3.82
14 12.759 3.817 1.48750 70.4 3.66
15 -28.129 1.366 1.90370 31.3 3.15
16 10.199 0.660 2.95
17 33.368 1.550 1.49700 81.6 2.98
18 -15.130 d3 3.00
19 * 500.000 1.709 1.54470 56.2 2.90
20 * 8.870 d4 2.84
21 * 43.550 3.978 1.54470 56.2 6.15
22 * -9.052 1.000 5.04
23 ∞ 0.300 1.52310 54.4 4.64
24 ∞ 1.000 4.61
25 ∞ 0.500 1.51680 64.2 4.43
26 ∞ 2.500 4.37

Aspheric coefficient

Surface 12 Surface 20
K = 0.00000E + 00 K = 0.00000E + 00
A4 = 0.50704E-04 A4 = -0.46497E-03
A6 = -0.22690E-04 A6 = 0.19108E-03
A8 = 0.32768E-05 A8 = -0.24110E-04
A10 = -0.19307E-06 A10 = 0.11871E-05
A12 = 0.41985E-08

Side 13 Side 21
K = 0.00000E + 00 K = 0.00000E + 00
A4 = 0.12790E-03 A4 = 0.41124E-04
A6 = -0.26446E-04 A6 = 0.11758E-04
A8 = 0.39638E-05 A8 = -0.15479E-06
A10 = -0.24375E-06 A10 = 0.10787E-08
A12 = 0.55207E-08

19th page 22nd page
K = 0.00000E + 00 K = 0.00000E + 00
A4 = -0.40111E-03 A4 = 0.50000E-03
A6 = 0.10829E-03 A6 = 0.17682E-06
A8 = -0.12878E-04 A8 = 0.16938E-06
A10 = 0.61419E-06 A10 = -0.18913E-08

Focal length of each position, F number, between groups

f Fno angle of view 2Y d1 d2 d3 d4
4.10 3.28 86.7 6.46 0.550 57.471 2.700 4.70
27.47 5.56 16.1 7.82 40.873 16.709 9.010 11.355
184.48 6.97 2.4 7.808 74.049 1.100 13.869 13.400

Lens group data

Lens group Start surface Focal length (mm)
1 1 101.89
2 6 -10.68
3 11 15.90
4 19 -16.60
5 21 14.14

  FIG. 8 is a cross-sectional view of the zoom lens of Example 4, FIG. 8 (a) is a cross-sectional view at the wide-angle end, FIG. 8 (b) is a cross-sectional view at the middle, and FIG. 8 (c) is the telephoto end. FIG. In the figure, Gr1 is a first lens group having a positive refractive power, Gr2 is a second lens group having a negative refractive power, Gr3 is a third lens group having a positive refractive power, and Gr4 is a first lens group having a negative refractive power. 4 lens group, Gr5 is a fifth lens group having positive refractive power, L1 is a first lens, L2 is a second lens, L3 is a third lens, L4 is a fourth lens, L5 is a fifth lens, and L6 is a fifth lens 6 lenses, L7 is the 7th lens, L8 is the 8th lens, L9 is the 9th lens, L10 is the 10th lens, L11 is the 11th lens, L12 is the 12th lens, S is the aperture stop, I is the imaging surface . F denotes a parallel plate assuming an optical low-pass filter, an IR cut filter, a seal glass of a solid-state image sensor, or the like. The first lens L1 is a 1-1 lens having a negative refractive power, the second lens L2 is a 1-2 lens having a positive refractive power, and the third lens is a first lens having a positive refractive power. -3 lens. The fourth lens L4 is a 2-1 lens having a negative refractive power, the fifth lens L5 is a 2-2 lens having a negative refractive power, and the sixth lens L6 has a positive refractive power. It is the 2nd-3 lens which has. Furthermore, the seventh lens L7 is a 3-1 lens having a positive refractive power, the eighth lens L8 is a third-2 lens having a positive refractive power, and the ninth lens L9 has a negative refractive power. The tenth lens L10 is a third lens having a positive refractive power, and the eighth lens L8 and the ninth lens L9 are cemented. The eleventh lens L11 is a single negative lens. The fourth lens group Gr4 and the fifth lens group GR5 are each composed of a single lens.

  FIG. 9 is an aberration diagram (spherical aberration, astigmatism, distortion) of the zoom lens of Example 4. Here, FIG. 9A is an aberration diagram at the wide-angle end. FIG. 9B is an aberration diagram in the middle. FIG. 9C is an aberration diagram at the telephoto end.

In the zoom lens of Example 4, when zooming, the first lens group Gr1, the second lens group Gr2, the third lens group Gr3, and the fourth lens group Gr4 move along the optical axis direction, and the interval between the lens groups. It is possible to change the magnification by changing. The fifth lens group Gr5 is fixed.
Further, by moving the fourth lens group Gr4, focusing from the infinity range to the finite distance range can be performed. It is assumed that the seventh lens L7 and the eleventh lens L11 are glass mold lenses, the twelfth lens L12 is a plastic lens, and the other lenses are polished lenses made of a glass material.

  Table 5 shows values of the respective examples corresponding to the respective conditional expressions.

  The present invention is not limited to the embodiments described in the specification, and includes other embodiments and modifications for those skilled in the art from the embodiments and technical ideas described in the present specification. it is obvious. The description and examples are for illustrative purposes only, and the scope of the invention is indicated by the following claims. For example, even when a dummy lens having substantially no power is further provided, it is within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Digital camera 2 Image pick-up part 3 Camera main-body part 4 Flash light emission part 5 Shutter button 6 Display part 7 EVF
8 switch 9 zoom switch Gr1-Gr5 lens group L1-L12 lens

Claims (13)

A first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a negative refractive power, which are arranged in order from the object side. In a zoom lens that includes a fourth lens group and a fifth lens group having positive refractive power, and performs zooming by changing the interval between the lens groups,
At the time of zooming, the respective lens groups from the first lens group to the fourth lens group move, and the fifth lens group does not move at the time of zooming or focusing, and satisfies the following conditional expression: A zoom lens characterized by that.
1.90 <(β2T / β2W) / (β3T / β3W) <3.40 (1)
3.00 <f3 / fw <4.50 (2)
However,
β2W: Lateral magnification at the wide-angle end of the second lens group β2T: Lateral magnification at the telephoto end of the second lens group β3W: Lateral magnification at the wide-angle end of the third lens group β3T: Telephoto end of the third lens group Lateral magnification f3: focal length (mm) of the third lens group
fw: focal length of the entire system at the wide-angle end (mm) The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
7.0 <| f1 / f2 | <12.0 (3)
However,
f1: Focal length (mm) of the first lens group
f2: Focal length (mm) of the second lens group The first lens group includes, in order from the object side, a first lens having a negative refractive power, a first lens having a positive refractive power, and a first lens having a positive refractive power. 3. The zoom lens according to claim 1, wherein at least one of the lenses having positive refractive power satisfies the following conditional expression: 4.
ν1P> 75 (4)
However,
ν1P: Abbe number of at least one lens having positive refractive power in the first lens group   The third lens group includes, in order from the object side, a 3-1 lens having positive refractive power, a 3-2 lens having positive refractive power, and a 3-3 lens having negative refractive power. 4. The lens according to claim 1, further comprising a third lens having a positive refractive power, wherein the third lens and the third lens are cemented. 5. The zoom lens according to item.   5. The camera shake correction group according to claim 1, wherein the third lens group is a camera shake correction group that optically corrects image blur on an image plane by moving in a direction perpendicular to the optical axis. The zoom lens according to item.   The zoom lens according to any one of claims 1 to 5, wherein the fourth lens group includes one negative lens.   The zoom lens according to claim 1, wherein focusing is performed by moving the fourth lens group in an optical axis direction. The zoom lens according to claim 1, wherein the fourth lens group satisfies the following conditional expression.
3.8 <| f4 / fw | <6.0 (5)
However,
f4: Focal length (mm) of the fourth lens group
fw: focal length of the entire system at the wide-angle end (mm)   The second lens group includes, in order from the object side, a 2-1 lens having a negative refractive power, a 2-2 lens having a negative refractive power, and a second-3 lens having a positive refractive power. The zoom lens according to claim 1, wherein the zoom lens is configured as follows. The zoom lens according to any one of claims 1 to 9, wherein the following conditional expression is satisfied.
0.01 <| f2 / ft | <0.15 (6)
However,
f1: Focal length (mm) of the second lens group
ft: focal length of the entire system at the telephoto end (mm)   The zoom lens according to claim 1, wherein the fifth lens group includes a single lens.   The zoom lens according to claim 1, further comprising a lens having substantially no refractive power.   An image pickup apparatus comprising: the zoom lens according to claim 1; and a solid-state image pickup device that photoelectrically converts an image formed by the zoom lens.

Images