JP2012255828A - Variable focal length lens device, imaging apparatus, adjustment method of variable focal length lens device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost variable focal length lens device capable of achieving excellent optical performance, an imaging apparatus, and an adjustment method of the variable focal length lens device.SOLUTION: The variable focal length lens device includes: an inner cylindrical member 2 which holds a first lens group including a plurality of lens groups G1, G2 and G3; an outer cylindrical member 1 which holds a second lens group including a plurality of lens groups G4 and G5 and to which the inner cylindrical member 2 is internally fitted; focal length adjustment means for adjusting the focal length by moving at least one movable lens group G2 in the first lens group and at least one movable lens group among the movable lens groups G4 and G5 in the second lens group along an optical axis O; and axis adjustment means for adjusting the optical axis of the first lens group in a direction substantially perpendicular to the optical axis of the second lens group.

Description

  The present invention relates to a variable focal length lens device, an imaging device, and a method for adjusting a variable focal length lens device.

  Conventionally, various photographing lenses suitable for a photographic camera, an electronic still camera, a video camera, and the like have been proposed. (For example, see Patent Document 1.)

Japanese Patent No. 4466028

  The conventional variable focal length lens device has a problem in that when an eccentric error occurs, the imaging performance deteriorates. Further, in order to prevent the deterioration of the imaging performance, it is necessary to increase the shape accuracy of each lens, lens chamber, and mechanism part to reduce the eccentric error, but it is difficult to reduce the cost because the demand for processing accuracy increases.

  The present invention has been made in view of the above problems, and can achieve good optical performance by minimizing decentration error, and adjustment of a low-cost variable focal length lens device, imaging device, and variable focal length lens device. It aims to provide a method.

  In order to solve the above-described problems, the present invention provides an inner cylinder member that holds a first lens group that includes a plurality of lens groups, and a second lens group that includes the plurality of lens groups by fitting the inner cylinder member therein. And moving at least one moving lens group in the first lens group and at least one moving lens group in the second lens group along the optical axis. A focal length adjusting means for adjusting the distance; and an aligning means for adjusting the optical axis of the first lens group in a direction substantially orthogonal to the optical axis of the second lens group. A variable focal length lens device is provided.

  In addition, the present invention provides an imaging device having the variable focal length lens.

  In addition, the present invention provides an inner cylinder member that holds a first lens group that includes a plurality of lens groups, and an outer cylinder that internally fits the inner cylinder member and holds a second lens group that includes a plurality of lens groups. A focal point for adjusting a focal length by moving a member, at least one moving lens group in the first lens group, and at least one moving lens group in the second lens group along the optical axis. An adjustment method of a variable focal length lens apparatus having a distance adjusting means, wherein the optical axis of the first lens group is adjusted in a direction substantially orthogonal to the optical axis of the second lens group. A variable focal length lens device adjustment method is provided.

  ADVANTAGE OF THE INVENTION According to this invention, a decentration error can be minimized and good optical performance can be achieved, and a low-cost variable focal length lens device, an imaging device, and a variable focal length lens device adjustment method can be provided.

1 is a cross-sectional configuration diagram of a variable focal length lens apparatus according to a first embodiment. The figure which looked at the variable focal length lens apparatus concerning a 1st embodiment from the object side. The figure which shows the transmission relationship of the information and control of the variable focal length lens apparatus of 1st Embodiment. Sectional drawing which shows the lens structure of the variable focal-length lens apparatus concerning 1st Embodiment. The aberration diagram with respect to d line ((lambda) = 587.6nm) in the infinite focus state of the variable focal-length lens apparatus concerning 1st Embodiment when the decentration error at the time of manufacture does not generate | occur | produce is shown, (a). Is the wide-angle end state, (b) is the intermediate focal length state, and (c) is the telephoto end state. An example of a coma aberration diagram with respect to the d-line (λ = 587.6 nm) in the infinite focus state of the variable focal length lens apparatus according to the first embodiment when an eccentric error occurs during manufacturing is shown. (A) Is the wide-angle end state, (b) is the intermediate focal length state, and (c) is the telephoto end state. In the variable focal length lens apparatus according to the first embodiment, a coma aberration diagram in the case where the position of the front lens group is adjusted in the direction orthogonal to the optical axis from the state where the eccentric error due to the manufacturing error has occurred is shown. Is the wide-angle end state, (b) is the intermediate focal length state, and (c) is the telephoto end state. Sectional drawing in the surface containing the optical axis of the variable focal-length lens apparatus concerning 2nd Embodiment. The figure which shows the transmission relationship of the information and control of the variable focal distance lens apparatus of the 2nd embodiment. Sectional drawing which shows the lens structure of the variable focal-length lens apparatus concerning 2nd Embodiment. The aberration diagram with respect to d line ((lambda) = 587.6nm) in the infinite focus state of the variable focal-length lens apparatus concerning 2nd Embodiment when the eccentric error at the time of manufacture does not generate | occur | produce is shown, (a). Is the wide-angle end state, (b) is the intermediate focal length state, and (c) is the telephoto end state. An example of a coma aberration diagram with respect to the d-line (λ = 587.6 nm) in the infinite focus state of the variable focal length lens apparatus according to the second embodiment when an eccentricity error occurs during manufacturing is shown. Is the wide-angle end state, (b) is the intermediate focal length state, and (c) is the telephoto end state. In the variable focal length lens apparatus according to the second embodiment, a coma aberration diagram in the case where the position of the rear lens group is adjusted in the direction orthogonal to the optical axis from the state where the eccentric error due to the manufacturing error has occurred is shown. Is the wide-angle end state, (b) is the intermediate focal length state, and (c) is the telephoto end state. 1 is a schematic configuration diagram of an imaging apparatus (single-lens reflex camera) equipped with a variable focal length lens apparatus according to a first embodiment.

  Hereinafter, each embodiment of a variable focal length lens device according to an embodiment of the present application will be described with reference to the drawings. The following embodiments are only for facilitating the understanding of the invention, and excluding additions and substitutions that can be performed by those skilled in the art without departing from the technical idea of the present invention. It is not intended.

(First embodiment)
The configuration of the variable focal length lens apparatus according to the first embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view of the variable focal length lens apparatus according to the first embodiment on a plane including the optical axis, and FIG. 2 is a view of the variable focal length lens apparatus according to the first embodiment as viewed from the object side. is there.

  As shown in FIGS. 1 and 2, the variable focal length lens device 10 according to the first embodiment includes an outer cylinder member 1 and an inner cylinder member 2 built in the object side of the outer cylinder member 1.

  The inner cylinder member 2 has a plurality (three in this embodiment) of through holes 2p formed in the object side end 2a of the inner cylinder member 2, and the screws 4 inserted into the through holes 2p are connected to the outer cylinder member 1. It is fixed by screwing into a screw hole 1s formed in the object side end 1a. The number of through holes 2p may be three or more. The diameter of the through hole 2p is formed larger than the diameter of the shaft portion of the screw 4.

  Further, the mount member 3 is fixed to the image side end 1c of the outer cylinder member 1 with a screw or the like (not shown), and is configured to be fixed to an imaging device described later by the mount member 3.

  A first lens group G1 is fixed to a lens frame 2aa formed at the object side end 2a of the inner cylinder member 2 so as to extend in the central axis (hereinafter referred to as the optical axis) O side direction of the outer cylinder member 1. ing. A third lens group G3 is fixed to a lens frame 2bb formed to extend in the direction of the optical axis O at the image side end 2b of the inner cylinder member 2. A first support member 21 is fixed between the object-side end 2a and the image-side end 2b near the inner periphery of the inner cylinder member 2.

  The second lens group G2 is fixed to the lens frame 12, and the lens frame 12 is supported by the first support member 21 so as to be movable along the optical axis O direction. The lens frame 12 is moved along the optical axis O by a first drive mechanism 31 fixed to the object side of the image side end 2b of the inner cylinder member 2.

  A diaphragm 24 is fixed to a fixing member 1b formed on the image side of the image side end 2b of the inner cylinder member 2 so as to extend from the outer cylinder member 1 toward the optical axis O direction.

  A second support member 22 is fixed near the inner periphery of the outer cylindrical member 1 between the fixing member 1b and the image side end 1c.

  The fourth lens group G4 is fixed to the lens frame 13, and the lens frame 13 is supported by the second support member 22 so as to be movable along the optical axis O. The lens frame 13 is moved along the optical axis O by a drive mechanism 32 fixed to the object side of the image side end 1c of the outer cylinder member 1.

  The third support member 23 is fixed at a position near the inner periphery of the outer cylinder member 1 between the fixing member 1b and the image side end portion 1c so that the lens frame 14 does not interfere with the lens frame 13.

  The fifth lens group G5 is fixed to the lens frame 14, and the lens frame 14 is supported by the third support member 23 so as to be movable along the optical axis O. Further, the lens frame 14 is moved along the optical axis O by the driving mechanism 33 fixed to the image side of the fixing member 1b.

  As described above, in the variable focal length lens apparatus 10 according to the first embodiment, the front lens group GF includes the first lens group G1, the second lens group G2, and the third lens group G3 arranged in the inner cylindrical member 2. The rear lens group GR is composed of the fourth lens group G4 and the fifth lens group G5 arranged in the outer cylinder member 1.

  Further, a switch member 40 for changing the focal length is provided outside the outer cylinder member 1. The outer cylinder member 1 is provided with a focal length detection means 41 for detecting the focal length changed by the switch member 40.

  FIG. 3 is a diagram showing the information / control transmission relationship of the variable focal length lens apparatus 10 according to the first embodiment.

  As shown in FIG. 3, the focal length is changed by the switch member 40, the changed focal length is detected by the focal length detection means 41, and this focal length information is transmitted to the control means 42. The control means 42 reads the position information of the second lens group G2, the fourth lens group G4, and the fifth lens group G5 corresponding to the focal length information from the storage means 43, and the first drive mechanism 31 is the second lens. In the group G2, the second driving mechanism 32 moves the fourth lens group G4, and the third driving mechanism 33 moves the fifth lens group G5.

  In the variable focal length lens apparatus 10 according to the first embodiment, when a decentration error occurs in each lens and each lens group due to a manufacturing error, a decentration aberration occurs, resulting in deterioration of imaging performance.

  As shown in FIGS. 1 and 2, the inner cylinder member 2 is provided with three through holes 2p, and the outer cylinder member 1 is provided with three screw holes 1s. The screw 4 is screwed into the screw hole 1s through the through hole 1p, and can be fixed after adjusting the position so that the inner cylinder member 2 is slightly decentered with respect to the outer cylinder member 1.

  In other words, the variable focal length lens apparatus 10 according to the first embodiment has the light of the front lens group GF composed of the first lens group G1, the second lens group G2, and the third lens group G3 held by the inner cylinder member 2. Adjustment is possible in which the axis is moved in a direction perpendicular to the optical axis of the rear lens group GR composed of the fourth lens group G4 and the fifth lens group G5 held by the outer cylinder member 1.

  In the variable focal length lens apparatus 10 according to the first embodiment, when it is found that the imaging performance is deteriorated due to decentration aberration after the variable focal length lens apparatus 10 is assembled, the screw 4 is loosened and the outer cylinder member 1 is removed. The inner cylinder member 2 is attached to the outer cylinder by adjusting the eccentric state of the optical axis of the front lens group GF of the inner cylinder member 2 with respect to the optical axis of the rear lens group GR and tightening the screw 4 at a position where the imaging performance is good. Secure to member 1.

  That is, the variable focal length lens device 10 according to the first embodiment can adjust and fix the position of the optical axis of the front lens group GF in the direction orthogonal to the optical axis of the rear lens group GR. Thereby, the variable focal length lens apparatus 10 according to the first embodiment can satisfactorily correct the deterioration of the imaging performance due to the decentration aberration.

  Next, comparison results of various aberrations when the variable focal length lens 10 according to the first embodiment is designed, when there is an eccentric error at the time of manufacture, and after adjustment of the eccentric error will be described.

  FIG. 4 is a cross-sectional view showing the lens configuration of the variable focal length lens apparatus 10 according to the first embodiment.

  As shown in FIG. 4, the lens system of the variable focal length lens apparatus 10 according to the first embodiment includes a front lens group GF, a diaphragm S, and a rear lens group GR in order from the object side. The front lens group GF is disposed in the inner cylinder member 2 in FIG. 1, and the rear lens group GR is disposed between the fixing member 1b of the outer cylinder member 1 and the image side end 1c. The front lens group GF can be adjusted in eccentricity with the configuration described above with respect to the rear lens group GR.

  The front lens group GF includes a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens group G3 having a positive refractive power, and the rear lens group GR. Consists of a fourth lens group G4 having negative refractive power and a fifth lens group G5 having positive refractive power.

  When changing the focal length from the wide-angle end state (W) to the telephoto end state (T), the second lens group G2, the fourth lens group G4, and the fifth lens group G5 are respectively moved in the optical axis direction.

  The image plane I is formed on an image pickup device of an image pickup device described later, and the image pickup device is composed of a CCD, a CMOS, or the like.

  Table 1 lists the specifications of the lens system of the variable focal length lens apparatus 10 according to the first embodiment. In (surface data) in the table, the object surface is the object surface, the surface number is the surface number from the object side, r is the radius of curvature, d is the surface spacing, and nd is the refraction with respect to the d-line (wavelength λ = 587.6 nm). The ratio, νd represents the Abbe number with respect to the d-line (wavelength λ = 587.6 nm), (aperture) represents the iris diaphragm S, and the image plane represents the image plane I. “R = ∞” indicates a plane. , Nd = 1.00000 (refractive index of air) is omitted.

In (Aspherical data), an aspherical surface is expressed by the following equation.
X (y) = (y ² / r) / [1+ {1−κ (y ² / r ² )} ^(1/2) ] + A4 · y ⁴ + A6 · y ⁶ + A8 · y ⁸ + A10 · y ¹⁰
Note that the height in the direction perpendicular to the optical axis is y, and the amount of displacement in the optical axis direction at the height y (the distance along the optical axis from the tangential plane of the apex of each aspheric surface to each aspheric surface) is X (y ), The curvature radius (paraxial curvature radius) of the reference spherical surface is r, the conic constant is κ, and the n-th order aspherical coefficient is An.

  In (various data), f is the focal length, FNO is the F number, 2ω is the angle of view, Y is the image height, TL is the total lens length, d5, d13, d22, and d27 are variable intervals, and Bf is the back focus. .

  (Lens group data) indicates the start surface number and end surface number of each lens group and the focal length of the lens group.

  In all the following specification values, “mm” is generally used as the focal length f, radius of curvature r, surface interval d and other lengths, etc. unless otherwise specified, but the optical system is proportional. Even if it is enlarged or proportionally reduced, the same optical performance can be obtained. Further, the unit is not limited to “mm”, and other appropriate units may be used. Furthermore, the description of these symbols is the same in other embodiments below, and the description thereof is omitted.

(Table 1)

(Surface data)
Surface number r d nd νd
Object ∞ ∞
1 74.1356 1.8000 1.850260 32.35
2 36.0351 7.0000 1.497820 82.51
3 3038.1597 0.1000
4 36.3362 5.0000 1.729157 54.66
5 170.0064 (d5)

6 159.7676 1.0000 1.816000 46.62
7 11.1111 5.7573
8 -57.3031 0.8000 1.816000 46.62
9 32.0791 0.2020
10 18.8298 4.0000 1.846660 23.78
11 -127.9381 0.3170
12 -90.0599 1.0000 1.816000 46.62
13 41.7316 (d13)

14 22.5107 0.8000 1.834000 37.16
15 12.0861 2.5000 1.603001 65.46
16 -69.1710 1.0000
17 864.1596 1.0000 1.850260 32.35
18 16.8557 2.2000 1.603001 65.46
19 -47.4738 0.1000
20 24.2921 1.8000 1.729157 54.66
21 -67.1681 1.0000
22 (Aperture) ∞ (d22)

23 -43.6868 0.8000 1.834807 42.72
24 22.6901 0.8000
25 -25.0831 0.8000 1.834807 42.72
26 11.7100 1.8000 1.846660 23.78
27 -48.7106 (d27)

28 24.1884 2.5000 1.497820 82.51
29 -58.4609 0.2000
30 40.9485 1.0000 1.834807 42.72
31 15.4156 3.5000 1.497820 82.51
32 -46.0872 8.5639
33 28.3973 2.5000 1.497820 82.51
34 -123.1319 3.7652
35 -20.5259 1.0000 1.846660 23.78
36 -54.7499 (Bf)
Image plane ∞

(Aspherical data)
6th surface κ = -20.0
A4 = + 4.26826E-06
A6 = -9.97395E-09
A8 = + 1.52813E-11
A10 = -3.70867E-14

(Various data)
f 10.30000 45.00000 97.00000
FNO 4.60 5.15 5.89
2ω 78.28 19.65 9.16
Y 8.00 8.00 8.00
TL 128.784 128.784 128.784
d5 0.80000 20.35470 28.02928
d13 28.05215 8.49747 0.82283
d22 0.80000 8.21034 13.11160
d27 16.13553 9.09292 6.83090
Bf 18.39100 18.02300 15.38400

(Lens group data)
Group Start surface End surface Focal length Front lens group 1 21 7.062 (wide-angle end state) to 55.262 (telephoto end state)
First lens group 1 5 57.577
Second lens group 6 13 -10.550
Third lens group 14 21 16.309
Rear lens group 23 36 51.294 (wide-angle end state) to -139.304 (telephoto end state)
Fourth lens group 23 27 -14.362
5th lens group 28 36 24.289

FIG. 5 is a diagram showing various aberrations with respect to the d-line (λ = 587.6 nm) in the infinitely focused state of the variable focal length lens apparatus 10 according to the first embodiment when no eccentric error occurs during manufacturing. (A) shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state. In each aberration diagram, FNO represents an F number, and Y represents an image height. In the astigmatism diagrams, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane. In addition, in the aberration diagrams of other embodiments described below, the same reference numerals as in this embodiment are used, and the following description is omitted.

  It can be seen that the variable focal length lens device 10 according to the first embodiment has high imaging performance with various aberrations corrected well.

  In the variable focal length lens apparatus 10 according to the first embodiment, when an eccentric error occurs during manufacture, decentration aberration occurs, resulting in deterioration of imaging performance. FIG. 6 is an example of a coma aberration diagram for the d-line (λ = 587.6 nm) in the infinite focus state of the variable focal length lens apparatus 10 according to the first embodiment when an eccentric error occurs during manufacturing. (A) shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state.

  FIG. 7 is a coma aberration diagram when the position of the front lens group GF is adjusted in a direction orthogonal to the optical axis from the state where an eccentricity error due to a manufacturing error has occurred, (a) is a wide-angle end state, (b). Indicates an intermediate focal length state, and (c) indicates a telephoto end state.

  Comparing the coma aberration diagrams of FIGS. 5, 6, and 7, it can be seen that in FIG. 7, the deterioration of the imaging performance due to the decentration error is well corrected and high imaging performance is obtained.

(Second Embodiment)
Next, a variable focal length lens apparatus according to a second embodiment of the present application will be described with reference to FIG. FIG. 8 is a cross-sectional view of the variable focal length lens apparatus according to the second embodiment on the plane including the optical axis.

  As shown in FIG. 8, the variable focal length lens device 100 includes an outer cylinder member 101 and an inner cylinder member 102 built in the image side of the outer cylinder member 101.

  The first lens group G1 is fixed to a lens frame 101a formed at the object side end of the outer cylinder member 101.

  In the middle of the outer cylinder member 101, there is provided a fixing member 101b formed to extend in the central axis (hereinafter referred to as the optical axis) O direction of the outer cylinder member 101. The fixing member 101b is provided with a lens frame 101bb on the object side, and the third lens group G3 is fixed. In addition, the stop S is disposed on the image side of the third lens group G3 in the fixed member 101b.

  A first support member 121 is fixed in the vicinity of the inner periphery of the outer cylinder member 101 between the object-side end 101a and the fixing member 101b.

  The second lens group G2 is fixed to the lens frame 112, and the lens frame 112 is supported by the first support member 121 so as to be movable along the optical axis O direction. The lens frame 112 is moved along the optical axis O by the first driving mechanism 131 fixed to the object side of the fixing member 101b.

  In the space between the fixed member 101b and the image side end portion 101c of the outer cylinder member 101, the inner cylinder member 102 is disposed.

  The inner cylinder member 102 has a plurality (three in this embodiment) of through holes 102p formed in the image side end portion 102b of the inner cylinder member 102, and screws 104 inserted into the through holes 102p are connected to the outer cylinder member 101. It is fixed by screwing into a screw hole 101s formed in the image side end portion 101d. The number of through holes 102p may be three or more. The diameter of the through hole 102p is formed larger than the diameter of the shaft portion of the screw 4.

  Further, the image side end portion 101c is fixed to the end portion of the portion 101e extending to the image side on the outer periphery of the image side end portion 101d of the outer cylinder member 101 with a screw or the like (not shown). A mount member 103 is fixed to the image-side end portion 101c with a screw or the like (not shown), and is fixed to an imaging apparatus described later by the mount member 103.

  A through hole 101f used when the screw 104 is rotated is formed in the image side end 101c at a position facing the screw hole 101s formed in the image side end 101d. The through hole 101f is closed by a hole filling member (not shown) after eccentricity adjustment, which will be described later.

  A second support member 122 is fixed near the inner periphery of the inner cylinder member 102 between the object-side end 102a and the image-side end 102b of the inner cylinder member 102.

  The fourth lens group G4 is fixed to the lens frame 113, and the lens frame 113 is supported by the second support member 122 so as to be movable along the optical axis O. The lens frame 113 is moved along the optical axis O by a drive mechanism 132 fixed to the object side of the image side end portion 102b of the inner cylinder member 101.

  The third support member 123 is fixed at a position near the inner periphery of the inner cylinder member 102 between the object-side end portion 102a and the image-side end portion 102b and at a position where the lens frame 114 does not interfere with the lens frame 113. Yes.

  The fifth lens group G5 is fixed to the lens frame 114, and the lens frame 114 is supported by the third support member 123 so as to be movable along the optical axis O. The lens frame 114 is moved along the optical axis O by a drive mechanism 133 fixed to the image side of the fixing member 102a.

  As described above, in the variable focal length lens device 100 according to the second embodiment, the front lens group GF includes the first lens group G1, the second lens group G2, and the third lens group G3 arranged in the outer cylinder member 1. The rear lens group GF is configured by the fourth lens group G4 and the fifth lens group G5 arranged in the inner cylinder member 2.

  Further, a switch member 140 for changing the focal length is provided outside the outer cylinder member 101. The outer cylinder member 101 is provided with focal length detection means 141 that detects the focal length changed by the switch member 140.

  FIG. 9 is a diagram showing the information / control transmission relationship of the variable focal length lens apparatus 100 according to the second embodiment.

  As shown in FIG. 9, the focal length is changed by the switch member 140, the changed focal length is detected by the focal length detection unit 141, and this focal length information is transmitted to the control unit 142. The control unit 142 reads the position information of the second lens group G2, the fourth lens group G4, and the fifth lens group G5 corresponding to the focal length information from the storage unit 143, and the first drive mechanism 131 is the second lens group. The group G2, the second drive mechanism 132 moves the fourth lens group G4, and the third drive mechanism 133 moves the fifth lens group G5.

  In the variable focal length lens apparatus 100 according to the second embodiment, when a decentration error occurs in each lens and each lens group due to a manufacturing error, decentration aberration occurs, resulting in deterioration of imaging performance.

  As shown in FIG. 8, the inner cylinder member 102 is provided with three through holes 102p, and the outer cylinder member 101 is provided with three screw holes 101s. The screw 4 is screwed into the screw hole 101s through the through hole 102p, and can be fixed after adjusting the position so that the inner cylinder member 102 is slightly decentered with respect to the outer cylinder member 101.

  In other words, the variable focal length lens apparatus 100 according to the second embodiment uses the optical axis of the rear lens group GR, which includes the fourth lens group G4 and the fifth lens group G5, held by the inner cylinder member 102 as the outer cylinder member. Adjustment is possible in which the lens is moved in a direction perpendicular to the optical axis of the front lens group GF including the first lens group G1, the second lens group G2, and the third lens group G3 held by the lens 101.

  When the variable focal length lens device 100 according to the second embodiment is found to have deteriorated imaging performance due to decentration aberration after the variable focal length lens device 100 is assembled, the screw 104 shown in FIG. 8 is loosened. The inner cylinder member is adjusted by adjusting the eccentricity of the optical axis of the rear lens group GR of the inner cylinder member 102 with respect to the optical axis of the front lens group GF of the outer cylinder member 101 and tightening the screw 104 at a position where the imaging performance is good. 102 is fixed to the outer cylinder member 101.

  That is, the variable focal length lens apparatus 100 according to the second embodiment can adjust and fix the position of the optical axis of the rear lens group GR in the direction orthogonal to the optical axis of the front lens group GF. Thereby, the variable focal length lens apparatus 100 according to the second embodiment can satisfactorily correct the deterioration of the imaging performance due to the decentration aberration.

  Next, comparison results of various aberrations when the variable focal length lens 100 according to the second embodiment is designed, when there is an eccentric error at the time of manufacture, and after adjustment of the eccentric error will be described.

  FIG. 10 is a cross-sectional view showing the lens configuration of the variable focal length lens apparatus 100 according to the second embodiment.

  As shown in FIG. 10, the lens system of the variable focal length lens apparatus 100 according to the second embodiment includes a front lens group GF, a stop S, and a rear lens group GR in order from the object side. Further, the front lens group GF is disposed between the object side end 101a of the outer cylinder member 101 and the fixing member 101b, and the rear lens group GR is disposed in the inner cylinder member 102 of FIG. The rear lens group GR can be adjusted in eccentricity with the above-described configuration with respect to the front lens group GF.

  The front lens group GF includes a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens group G3 having a positive refractive power, and the rear lens group GR. Consists of a fourth lens group G4 having negative refractive power and a fifth lens group G5 having positive refractive power.

  When changing the focal length from the wide-angle end state (W) to the telephoto end state (T), the second lens group G2, the fourth lens group G4, and the fifth lens group G5 are moved in the optical axis direction.

  The image plane I is formed on an image pickup device of an image pickup device described later, and the image pickup device is composed of a CCD, a CMOS, or the like.

  Table 2 lists the specifications of the lens system of the variable focal length lens apparatus 100 according to the second embodiment.

(Table 2)

(Surface data)
Surface number r d nd νd
Object ∞ ∞
1 74.1356 1.8000 1.850260 32.35
2 36.0351 7.0000 1.497820 82.51
3 3038.1597 0.1000
4 36.3362 5.0000 1.729157 54.66
5 170.0064 (d5)

6 159.7676 1.0000 1.816000 46.62
7 11.1111 5.7573
8 -57.3031 0.8000 1.816000 46.62
9 32.0791 0.2020
10 18.8298 4.0000 1.846660 23.78
11 -127.9381 0.3170
12 -90.0599 1.0000 1.816000 46.62
13 41.7316 (d13)

14 22.5107 0.8000 1.834000 37.16
15 12.0861 2.5000 1.603001 65.46
16 -69.1710 1.0000
17 864.1596 1.0000 1.850260 32.35
18 16.8557 2.2000 1.603001 65.46
19 -47.4738 0.1000
20 24.2921 1.8000 1.729157 54.66
21 -67.1681 1.0000
22 (Aperture) ∞ (d22)

23 -43.6868 0.8000 1.834807 42.72
24 22.6901 0.8000
25 -25.0831 0.8000 1.834807 42.72
26 11.7100 1.8000 1.846660 23.78
27 -48.7106 (d27)

28 24.1884 2.5000 1.497820 82.51
29 -58.4609 0.2000
30 40.9485 1.0000 1.834807 42.72
31 15.4156 3.5000 1.497820 82.51
32 -46.0872 8.5639
33 28.3973 2.5000 1.497820 82.51
34 -123.1319 3.7652
35 -20.5259 1.0000 1.846660 23.78
36 -54.7499 (Bf)
Image plane ∞

(Aspherical data)
6th surface κ = -20.0
A4 = + 4.26826E-06
A6 = -9.97395E-09
A8 = + 1.52813E-11
A10 = -3.70867E-14

(Various data)
f 10.30000 45.00000 97.00000
FNO 4.60 5.15 5.89
2ω 78.28 19.65 9.16
Y 8.00 8.00 8.00
TL 128.784 128.784 128.784
d5 0.80000 20.35470 28.02928
d13 28.05215 8.49747 0.82283
d22 0.80000 8.21034 13.11160
d27 16.13553 9.09292 6.83090
Bf 18.39100 18.02300 15.38400

(Lens group data)
Group Start surface End surface Focal length Front lens group 1 21 7.062 (wide-angle end state) to 55.262 (telephoto end state)
First lens group 1 5 57.577
Second lens group 6 13 -10.550
Third lens group 14 21 16.309
Rear lens group 23 36 51.294 (wide-angle end state) to -139.304 (telephoto end state)
Fourth lens group 23 27 -14.362
5th lens group 28 36 24.289

FIG. 11 is a diagram showing various aberrations with respect to the d-line (λ = 587.6 nm) in the infinitely focused state of the variable focal length lens apparatus 100 according to the second embodiment when no eccentric error occurs during manufacturing. (A) shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state.

  It can be seen that the variable focal length lens apparatus 100 according to the second embodiment has high imaging performance with various aberrations corrected well.

  In the variable focal length lens apparatus 100 according to the second embodiment, when an eccentric error occurs during manufacture, decentering aberration occurs, resulting in deterioration of imaging performance. FIG. 12 is an example of a coma aberration diagram for the d-line (λ = 587.6 nm) in the infinite focus state of the variable focal length lens apparatus 100 according to the second embodiment when an eccentric error occurs during manufacturing. (A) shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state.

  FIG. 13 is a coma aberration diagram in the case where the position of the rear lens group GR is adjusted in the direction orthogonal to the optical axis from the state where the eccentric error due to the manufacturing error occurs, (a) is the wide-angle end state, (b) Indicates an intermediate focal length state, and (c) indicates a telephoto end state.

  Comparing the coma aberration diagrams of FIGS. 11, 12, and 13, it can be seen that in FIG. 13, the deterioration of the imaging performance due to the decentration error is well corrected and high imaging performance is obtained.

  As described above, the variable focal length lens device according to the embodiment of the present application makes it possible to adjust the eccentricity of one of the front lens group and the rear lens group, thereby adjusting the eccentric error generated during the manufacturing process, thereby achieving high image formation. Performance can be achieved.

  In each of the above-described embodiments, the variable focal length lens apparatus having the five-group configuration has been described. However, the present invention is applicable to variable focal length lens apparatuses having six or more groups. Further, in the variable focal length lens apparatus having six or more groups, the number of moving lens groups is not limited to three, and four or more moving lens groups can be applied. In the case where there are four or more moving lens groups, the storage means stores the position information of three or four moving lens groups.

  Next, an imaging apparatus equipped with the variable focal length lens apparatus according to the embodiment will be described with reference to FIG. FIG. 14 is a schematic configuration diagram of an imaging apparatus (single-lens reflex camera) equipped with the variable focal length lens apparatus 10 according to the first or second embodiment.

  In FIG. 14, light from a subject (not shown) is collected by the variable focal length lens devices 10 and 100, reflected by the quick return mirror 53 and imaged on the focusing screen 54. The subject image formed on the focusing screen 54 is reflected by the pentaprism 55 a plurality of times, and can be viewed as an erect image by the photographer via the eyepiece lens 56.

  The photographer observes the subject image through the eyepiece lens 56 while half-pressing a release button (not shown), determines the shooting composition, and then fully presses the release button. When the release button is fully pressed, the quick return mirror 53 is flipped upward, the light from the subject is received by the image sensor 57, and a captured image is acquired and recorded in a memory (not shown).

  Thus, the camera 51 which is an imaging device including the variable focal length lens devices 10 and 100 according to the embodiment is configured. The camera 51 shown in FIG. 14 may be one that holds the variable focal length lens devices 10 and 100 in a detachable manner, or may be formed integrally with the variable focal length lens devices 10 and 100. The camera 51 may be a so-called single-lens reflex camera or a compact camera that does not have a quick return mirror or the like.

DESCRIPTION OF SYMBOLS 1,101 Outer cylinder member 2,102 Inner cylinder member 3,103 Mount member 4,104 Screw 10,100 Variable focal length lens apparatus 12,112 Lens frame 13,113 Lens frame 14,114 Lens frame 21,121 1st Support member 22, 122 Second support member 23, 123 Third support member 31, 131 First drive mechanism 32, 132 Second drive mechanism 33, 133 Third drive mechanism 40, 140 Switch member 41, 141 Focal length detection means 42, 142 Control means 43, 143 Storage means 51 Imaging device (camera)
53 Quick Return Mirror 54 Focusing Plate 55 Penta Prism 56 Eyepiece 57 Image Sensor G1 First Lens Group G2 Second Lens Group G3 Third Lens Group G4 Fourth Lens Group G5 Fifth Lens Group S Aperture I Image Surface O Optical Axis

Claims (10)

An inner cylinder member that holds a first lens group including a plurality of lens groups;
An outer cylinder member that internally fits the inner cylinder member and holds a second lens group including a plurality of lens groups;
Focal length adjusting means for adjusting the focal length by moving at least one moving lens group in the first lens group and at least one moving lens group in the second lens group along the optical axis. When,
A variable focal length lens apparatus comprising: an aligning unit that adjusts an optical axis of the first lens group in a direction substantially orthogonal to the optical axis of the second lens group.   The alignment means includes a plurality of holes formed in the inner cylinder member, a plurality of screw holes corresponding to the plurality of holes formed in the outer cylinder member, and the holes inserted into the holes. The variable focal length lens device according to claim 1, comprising a plurality of screws to be screwed together. The inner cylinder member is fitted on the object side of the outer cylinder member,
The alignment means includes a plurality of holes formed at the object side end of the inner cylinder member, a plurality of screw holes corresponding to the plurality of holes formed at the object side end of the outer cylinder member, The variable focal length lens device according to claim 1 or 2, comprising a plurality of screws inserted into the holes and screwed into the screw holes. The inner cylinder member is fitted on the image side of the outer cylinder member,
The alignment means includes a plurality of holes formed at the image side end of the inner cylinder member, and a plurality of screw holes corresponding to the plurality of holes formed at the image side end of the outer cylinder member; The variable focal length lens device according to claim 1 or 2, comprising a plurality of screws inserted into the holes and screwed into the screw holes. The focal length adjusting means is
Detecting means for detecting a change in focal length;
Storage means for storing positions on the optical axis for each of the focal lengths of the plurality of moving lens groups;
A plurality of independent drive means for respectively driving the plurality of moving lens groups;
Control means for moving a plurality of the moving lens groups to the positions stored in the storage means via the plurality of driving means based on the output from the detection means, respectively. The variable focal length lens apparatus according to claim 1.   6. The variable focal length lens device according to claim 5, wherein each of the plurality of driving means is mechanically disposed independently of each other. In order from the object side, 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 fourth lens group having a negative refractive power; A fifth lens unit having positive refractive power,
The first lens group includes the first lens group, the second lens group, and the third lens group,
The second lens group includes the fourth lens group and the fifth lens group,
The moving lens group in the first lens group consists of the second lens group,
The variable focal length lens apparatus according to claim 1, wherein the movable lens group in the second lens group includes the fourth lens group and the fifth lens group. . In order from the object side, 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 fourth lens group having a negative refractive power; A fifth lens unit having positive refractive power,
The second lens group includes the first lens group, the second lens group, and the third lens group,
The first lens group includes the fourth lens group and the fifth lens group,
The moving lens group in the second lens group consists of the second lens group,
7. The variable focal length lens device according to claim 1, wherein the moving lens group in the first lens group includes the fourth lens group and the fifth lens group. 8. .   An imaging apparatus comprising the variable focal length lens according to claim 1. An inner cylinder member that holds a first lens group including a plurality of lens groups;
An outer cylinder member that internally fits the inner cylinder member and holds a second lens group including a plurality of lens groups;
Focal length adjusting means for adjusting the focal length by moving at least one moving lens group in the first lens group and at least one moving lens group in the second lens group along the optical axis. A method for adjusting a variable focal length lens device having:
An adjustment method for a variable focal length lens apparatus, wherein the optical axis of the first lens group is adjusted in a direction substantially orthogonal to the optical axis of the second lens group.

Images