JP5914998B2 - Variable focal length lens device, imaging apparatus, and variable focal length lens device adjustment method - Google Patents

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.)

Patent No. 4466028

  In conventional variable focal length lens devices, if there are manufacturing errors such as lens center thickness, lens spacing, lens surface curvature, lens refractive index, etc., spherical aberration or astigmatism changes from the design value, resulting in degradation of imaging performance. There was a problem that caused. In order to prevent the deterioration of the imaging performance, a predetermined lens interval or lens group interval is intentionally shifted from the design value to correct the imaging performance deterioration. It has been difficult to satisfactorily correct the imaging performance in the focal length region.

  The present invention has been made in view of the above problems, and a variable focal length lens device and an imaging apparatus including the variable focal length lens device capable of achieving good optical performance in the entire focal length region of the variable focal length lens. An object of the present invention is to provide a method for adjusting a variable focal length lens device.

In order to solve the above problems, the present invention provides:
A lens barrel;
A holding member for holding a plurality of lens groups in the lens barrel;
Independent driving means for respectively moving at least three moving lens groups of the plurality of lens groups along the optical axis;
An operation unit for changing the focal length;
A focal length detection means for detecting the focal length changed by the operation unit;
Memory means for storing the position change of position relative to the prior SL designed value on the optical axis of at least two respective moving lens unit wide angle end state of the moving lens group for each of the focal length,
Based on the focal length information detected by the focal length detection means, the moving lens is moved to a position on the optical axis via the driving means based on the position change of the at least two moving lens groups. Control means for positioning each group;
A variable focal length lens apparatus is provided.

  The present invention also provides an imaging apparatus comprising the variable focal length lens device.

The present invention also provides:
A lens barrel;
A holding member for holding a plurality of lens groups in the lens barrel;
Independent driving means for respectively moving at least three moving lens groups of the plurality of lens groups along the optical axis;
An operation unit for changing the focal length;
A focal length detection means for detecting the focal length changed by the operation unit;
Memory means for storing the position change of position relative to the prior SL designed value on the optical axis of at least two respective moving lens unit wide angle end state of the moving lens group for each of the focal length,
Control means for controlling the drive means,
Based on the focal length information detected by the focal length detection means, the control means moves the at least two moving lens groups on the optical axis via the driving means based on the position changes. Provided is a variable focal length lens apparatus adjustment method characterized by positioning each of the moving lens groups at a position.

  According to the present invention, there are provided a variable focal length lens device capable of achieving good optical performance in the entire focal length region of the variable focal length lens, an imaging device equipped with the variable focal length lens device, and a variable focal length lens 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 shows the transmission relationship of the information and control of the variable focal length lens apparatus concerning 1st Embodiment. Sectional drawing which shows the lens structure of the variable focal-length lens apparatus concerning 1st Embodiment. FIG. 5A shows various aberration diagrams for the d-line (λ = 587.6 nm) in the infinitely focused state based on the design value of the variable focal length lens apparatus according to the first embodiment, (a) is a wide-angle end state, and (b). Indicates an intermediate focal length state, and (c) indicates a telephoto end state. An example of various aberration diagrams with respect to the d-line (λ = 587.6 nm) in the infinite focus state when a manufacturing error occurs even though the variable focal length lens device according to the first embodiment is assembled according to the design value. (A) shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state. As a result of correcting various aberrations by shifting the positions of the fourth lens group and the fifth lens group from the design value for each focal length from the state where the manufacturing error has occurred in the variable focal length lens apparatus according to the first embodiment. The aberration diagrams for the d-line (λ = 587.6 nm) in the infinity in-focus state, where (a) is the wide-angle end state, (b) is the intermediate focal length state, and (c) is the telephoto end state. Each is shown. The cross-sectional block diagram 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 concerning 2nd Embodiment. Sectional drawing which shows the lens structure of the variable focal-length lens apparatus concerning 2nd Embodiment. FIG. 5A shows various aberration diagrams for the d-line (λ = 587.6 nm) in the infinitely focused state based on the design value of the variable focal length lens apparatus according to the second embodiment, where FIG. Indicates an intermediate focal length state, and (c) indicates a telephoto end state. An example of various aberration diagrams with respect to the d-line (λ = 587.6 nm) in an infinitely focused state when a manufacturing error occurs even though the variable focal length lens apparatus according to the second embodiment is assembled according to the design value. (A) shows the wide-angle end state, (b) shows the intermediate focal length state, and (c) shows the telephoto end state. As a result of correcting various aberrations by shifting the positions of the fourth lens group and the fifth lens group from the design value for each focal length from the state in which the manufacturing error has occurred in the variable focal length lens apparatus according to the second embodiment. The aberration diagrams for the d-line (λ = 587.6 nm) in the infinity in-focus state, where (a) is the wide-angle end state, (b) is the intermediate focal length state, and (c) is the telephoto end state. Each is shown. The figure which shows an example of the imaging device carrying the variable focal distance lens apparatus concerning this embodiment.

  Hereinafter, 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.

  In FIG. 1, the variable focal length lens apparatus 10 according to the first embodiment has a first lens group G1 fixed to the lens barrel member 1 on the optical axis via a first lens group fixing portion 1a, and a third lens group fixed. The third lens group G3 is fixed on the optical axis via the portion 1b, and the second lens group G2 is located between the first lens group G1 and the third lens group G3 on the image side of the third lens group G3. The fourth lens group G4 and the fifth lens group G5 are held by members to be described later in the barrel member 1 so as to be independently movable along the optical axis.

  A mount member 2 is fixed to the image-side end 1c of the lens barrel member 1, and is fixed to an imaging device described later by the mount member 2.

  A pin 2b extending in the radial direction from the lens frame 2a holding the second lens group G2 is a cam groove formed in the operation member 31 for changing the focal length through the long hole 3 opened in the lens barrel member 1. It is engaged with 31a. When the operation member 31 is rotated, the pin 2b moves along the cam groove 31a formed on the inner wall of the operation member 31, and thereby the second lens group G2 moves along the optical axis.

  The operation member 31 is connected to the focal length detection means 32 disposed on the lens barrel member 1 through the interlocking means 32a. When the operation member 31 is operated, the focal length detection unit 32 detects it via the interlocking unit 32 a and detects the value of the focal length changed by the operation member 31.

  The fourth lens group G4 is held by a fourth lens group lens frame 4a, and this lens frame 4a is disposed on a first support member 23 disposed between the third lens group fixing portion 1b and the image side end portion 1c. It is supported so as to be slidable, and is configured to move along the optical axis by the first drive mechanism 21 on the basis of a control signal from a control means 35 described later shown in FIG.

  The fifth lens group G5 is held by a fifth lens group lens frame 5a, and this lens frame 5a is attached to a second support member 24 disposed between the third lens group fixing portion 1b and the image side end portion 1c. The second drive mechanism 22 is supported so as to be slidable and moves along the optical axis based on a control signal from the control means 35.

  In addition, when the variable focal length lens 10 according to the first embodiment is manufactured, when the variable focal length lens 10 is manufactured, the lens center thickness, the lens interval, the curvature of the lens surface, and the refractive index of the lens deviate from the design values of the lens. The positional information on the optical axis of each of the fourth lens group G4 and the fifth lens group G5 when various aberrations for each focal length are corrected well is stored in the storage means 34. As the position information of each of the fourth lens group G4 and the fifth lens group G5, the position change on the optical axis is stored with reference to the design value in the wide-angle end state. Further, it is acquired at a plurality of focal length positions in the total focal length region of the variable focal length lens apparatus 10 and stored in the storage means 34. Note that the position information of the fourth lens group G4 and the fifth lens group G5 at the focal length position that is not stored is set by the control means 35 performing processing such as interpolation processing based on the stored position information. Can do. Thus, the variable focal length lens apparatus 10 according to the first embodiment is configured.

  In the variable focal length lens apparatus 10 according to the first embodiment, as shown in FIG. 2, the focal length changed by operating the operation member 31 is detected by the focal length detection unit 32 via the interlocking member 32a. It is detected and transmitted to the control means 35. The control unit 35 reads position information on the optical axis of the fourth lens group G4 and the fifth lens group G5 corresponding to the transmitted focal length from the storage unit 34, and the fourth lens via the first driving mechanism 21. The fifth lens group G5 is independently moved to a predetermined optical axis position via the second drive mechanism 22 in the group.

  As a result, the variable focal length lens apparatus 10 according to the first embodiment controls the positions of the fourth lens group G4 and the fifth lens group G5 on the optical axis at each focal length obtained by operating the operation member 31. By correcting the means 35 based on the position information stored in the storage means 34, various aberrations can be corrected well over the entire focal length region.

  Next, various aberrations when the positions of the fourth lens group G4 and the fifth lens group G5 are changed so as to correct various aberrations and manufacturing errors in designing the variable focal length lens 10 according to the first embodiment. The comparison result will be described.

  FIG. 3 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. 3, each lens group of the variable focal length lens apparatus 10 according to the first embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power and a first lens group G1 having a negative refractive power. It consists of a two-lens group G2, a third lens group G3 having a positive refractive power, a stop S, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power.

  The image plane I is formed on an image sensor (not shown), and the image sensor is composed of a CCD, a CMOS, or the like.

  Table 1 below lists specifications 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.

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 First lens group 1 5 57.577
Second lens group 6 13 -10.550
Third lens group 14 21 16.309
Fourth lens group 23 27 -14.362
5th lens group 28 36 24.289

FIG. 4 is a diagram illustrating various aberrations with respect to the d-line (λ = 587.6 nm) in the infinite focus state based on the design value of the variable focal length lens apparatus 10 according to the first embodiment. (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 various aberration diagrams of the following examples, the same reference numerals as those of the present 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.

  On the other hand, in the variable focal length lens apparatus 10 according to the first embodiment, the lens center thickness, the lens interval, the curvature of the lens surface, and the refractive index of the lens deviate from the above design values due to manufacturing errors during assembly and manufacturing. As a result, various aberrations including astigmatism increase, resulting in degradation of imaging performance.

  FIG. 5 shows the d-line (λ = 587.6 nm) in the infinitely focused state when a manufacturing error occurs even though the variable focal length lens apparatus 10 according to the first embodiment is assembled according to the design value. An example of various aberration diagrams is shown. It can be seen that astigmatism is mainly deteriorated among various aberrations.

  FIG. 6 shows the state in which a manufacturing error has occurred in the variable focal length lens apparatus 10 according to the first embodiment, in which the control unit 35 and the fourth lens group G4 and the first lens unit G4 through the first driving unit 21 according to the above description. D line (λ = 587...) In the infinite focus state, which is the result of correcting various aberrations by shifting the position of the fifth lens group G5 from the design value for each focal length via the driving means 22 of No. 2. The aberration diagrams for 6 nm) are shown.

  Table 2 below shows the design values of the positional information of the fourth lens group G4 and the fifth lens group G5, the corrected values, the back focus in a state where a manufacturing error has occurred, and the corrected back focus. . In Table 2, f is the focal length, M4A is the position of the fourth lens group G4 at the design value, M5A is the position of the fifth lens group G5 at the design value, M4B is the position of the corrected fourth lens group G4, M5B is the corrected position of the fifth lens group G5, and each position is shown with the position of the design value in the wide-angle end state as a reference, and the movement toward the image side is positive and the movement toward the object side is negative. Bf1 represents a back focus in a state where a manufacturing error has occurred, and Bf2 represents a back focus value after correcting the positions of the fourth lens group G4 and the fifth lens group G5. dI1 is the value of the imaging position when a manufacturing error has occurred with respect to the imaging position at the design value, dI2 is the value of the corrected imaging position with respect to the imaging position at the design value, and the deviation to the object side Shown as negative. The description of the above symbols is the same in other embodiments, and the subsequent description is omitted.

(Table 2)

f 10.30000 45.00000 97.00000
M4A 0.00000 7.41033 12.31159
M5A 0.00000 0.36772 3.00696
M4B 0.13000 7.59000 12.60000
M5B 0.13000 0.73147 3.49047
Bf1 18.53660 18.21911 15.80965
Bf2 18.25865 17.66084 14.89724
dI1 0.14560 0.19611 0.42565
dI2 0.00235 0.00158 -0.00326

Comparing the various aberration diagrams of FIGS. 4, 5, and 6, in FIG. 6, the variable focal length lens apparatus 10 according to the first embodiment has good imaging performance degradation due to manufacturing errors in the entire focal length region. As can be seen from FIG. Further, from Table 2, it can be seen that the variable focal length lens apparatus 10 according to the first embodiment also corrects the deviation of the back focus Bf.

(Second Embodiment)
The configuration of the variable focal length lens apparatus according to the second embodiment will be described with reference to FIGS.

  As shown in FIG. 7, in the variable focal length lens device 100 of the second embodiment, the first lens group G1 is fixed on the optical axis via the first lens group fixing portion 101a to the lens barrel member 101, and the third The third lens group G3 is fixed on the optical axis via the lens group fixing unit 101b, and the second lens group G2 is an image of the third lens group G3 between the first lens group G1 and the third lens group G3. On the side, the fourth lens group G4 and the fifth lens group G5 are held by members to be described later in the barrel member 101 so as to be independently movable along the optical axis.

  In addition, a switch member 136 for changing the focal length is provided outside the lens barrel member 101. The lens barrel member 101 is provided with focal length detection means 132 that detects the focal length changed by the switch member 136.

  A mount member 102 is fixed to the image side end portion 101c of the lens barrel member 101, and is fixed to an imaging device described later by the mount member 102.

  The second lens group G2 is held by the second lens group lens frame 102a, and the third support member is disposed between the first lens group fixing part 101a and the third lens group fixing part 101b. 126 is slidably supported, and is configured to move along the optical axis by the third drive mechanism 125 based on a control signal from the control means 135 shown in FIG.

  The fourth lens group G4 is held by a fourth lens group lens frame 104a, and the lens frame 104a is attached to a first support member 123 disposed between the third lens group fixing portion 101b and the image side end portion 101c. It is supported so as to be slidable, and is configured to move along the optical axis by the first drive mechanism 121 based on a control signal from the control means 135.

  The fifth lens group G5 is held by a fifth lens group lens frame 105a, and this lens frame 5a is attached to a second support member 124 disposed between the third lens group fixing portion 101b and the image side end portion 101c. It is supported so as to be slidable, and is configured to move along the optical axis by the second drive mechanism 122 based on a control signal from the control means 135.

  Further, in the variable focal length lens 100 according to the second embodiment, when the variable focal length lens 100 is manufactured, the lens center thickness, the lens interval, the lens surface curvature, and the refractive index of the lens deviate from the design values of the lens. The positional information on the optical axis of each of the fourth lens group G4 and the fifth lens group G5 when the various aberrations for each focal length are corrected well is stored in the storage means 134. As the position information of each of the fourth lens group G4 and the fifth lens group G5, the position change on the optical axis is stored with reference to the design value in the wide-angle end state. The position information is acquired at a plurality of focal lengths in the total focal length region of the variable focal length lens apparatus 100 and stored in the storage unit 134. Note that the position information of the fourth lens group G4 and the fifth lens group G5 having a focal length that is not stored can be set by the control means 135 performing processing such as interpolation processing based on the stored position information. it can. Thus, the variable focal length lens apparatus 100 according to the second embodiment is configured.

  In the variable focal length lens apparatus 100 according to the second embodiment, as shown in FIG. 8, the focal length detected by the focal length detection unit 132 when the switch member 136 is operated is transmitted to the control unit 135. . The control means 135 reads position information on the optical axis of the second lens group G2, the fourth lens group G4, and the fifth lens group G5 corresponding to the transmitted focal length from the storage means 134, and the first drive mechanism The fourth lens group G 4 via 121, the fifth lens group G 5 via the second drive mechanism 122, and the second lens group G 2 via the third drive means 125 are each independently given a predetermined optical axis. Move to position.

  As a result, in the variable focal length lens apparatus 100 according to the second embodiment, when the focal length is changed by operating the switch member 136, the optical axes of the fourth lens group G4 and the fifth lens group G5 at each focal length. By correcting the upper position based on the position information stored in the storage unit 134 by the control unit 135, various aberrations can be corrected well over the entire focal length region.

  Next, various aberrations when the positions of the fourth lens group G4 and the fifth lens group G5 are changed so as to correct various aberrations and manufacturing errors in designing the variable focal length lens apparatus 100 according to the second embodiment. The comparison result will be described.

  FIG. 9 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. 9, each lens group of the variable focal length lens apparatus 100 according to the second embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power and a first lens group G1 having a negative refractive power. It consists of a two-lens group G2, a third lens group G3 having a positive refractive power, a stop S, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power.

  The image plane I is formed on an image sensor (not shown), and the image sensor is composed of a CCD, a CMOS, or the like.

Table 3 below lists specifications of the variable focal length lens apparatus 100 according to the second embodiment.
(Table 3)

(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 First lens group 1 5 57.577
Second lens group 6 13 -10.550
Third lens group 14 21 16.309
Fourth lens group 23 27 -14.362
5th lens group 28 36 24.289

FIG. 10 is a diagram illustrating various aberrations with respect to the d-line (λ = 587.6 nm) in an infinitely focused state based on the design value of the variable focal length lens apparatus 100 according to the second embodiment. (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.

  On the other hand, in the variable focal length lens apparatus 100 according to the second embodiment, the lens center thickness, the lens interval, the lens surface curvature, and the lens refractive index deviate from the above design values due to manufacturing errors during assembly and manufacturing. As a result, various aberrations including astigmatism increase, resulting in degradation of imaging performance.

  FIG. 11 shows the d-line (λ = 587.6 nm) in the infinitely focused state when a manufacturing error occurs even though the variable focal length lens apparatus 100 according to the second embodiment is assembled according to the design value. An example of various aberration diagrams is shown. It can be seen that astigmatism is mainly deteriorated among various aberrations.

  FIG. 12 illustrates a state in which a manufacturing error has occurred in the variable focal length lens apparatus 100 according to the second embodiment, in which the control unit 135 performs the fourth lens group G4 and the first lens unit G4 through the first driving unit 121 according to the above description. The d-line (λ = 587) in the infinite focus state, which is a result of correcting various aberrations by shifting the position of the fifth lens group G5 from the design value for each focal length via the second driving means 122. The aberration diagrams for .6 nm) are shown.

  Table 4 below shows the design values of the positional information of the fourth lens group G4 and the fifth lens group G5, the corrected values, the back focus in a state where a manufacturing error has occurred, and the corrected back focus. .

(Table 4)

f 10.30000 45.00000 97.00000
M4A 0.00000 7.41033 12.31159
M5A 0.00000 0.36772 3.00696
M4B 0.13000 7.59000 12.60000
M5B 0.13000 0.73147 3.49047
Bf1 18.53660 18.21911 15.80965
Bf2 18.25865 17.66084 14.89724
dI1 0.14560 0.19611 0.42565
dI2 0.00235 0.00158 -0.00326

10, 11, and 12 are compared. In FIG. 12, the variable focal length lens apparatus 100 according to the second embodiment shows that the imaging performance deteriorates due to manufacturing errors in the entire focal length range. As can be seen from FIG. Further, it can be seen from Table 4 that the variable focal length lens apparatus 100 according to the second embodiment also corrects the back focus shift well.

  As described above, the variable focal length lens apparatus according to the embodiment of the present invention stores in advance in the storage means the positions on the optical axis of the fourth lens group and the fifth lens group that favorably correct various aberrations at each focal length. The control means drives the fourth and fifth lens groups independently through the respective driving means based on the position information stored according to each focal length, and arranges them at a predetermined optical axis position. Various aberrations can be satisfactorily corrected in the entire focal length region.

  In each of the above-described embodiments, the variable focal length lens apparatus having a five-group configuration has been described. 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 unit can store the position information of the three or four moving lens groups, and thereby achieve the same effect as the embodiment.

  Next, an imaging apparatus equipped with the variable focal length lens apparatus according to the present embodiment will be described with reference to FIG. FIG. 13 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 embodiment.

  In FIG. 13, light from a subject (not shown) is collected by the variable focal length lens device 10, reflected by the quick return mirror 43 and imaged on the focusing screen 44. The subject image formed on the focusing screen 44 is reflected by the pentaprism 45 a plurality of times and can be viewed as an erect image by the photographer via the eyepiece 46.

  The photographer presses the release button fully after observing the subject image via the eyepiece lens 46 and determining the shooting composition while pressing the release button (not shown) halfway. When the release button is fully pressed, the quick return mirror 43 is flipped upward, the light from the subject is received by the image sensor 47, and a photographed image is acquired and recorded in a memory (not shown).

  In this manner, the camera 41 that is an imaging apparatus including the variable focal length lens apparatus 10 according to the present embodiment is configured. Note that the camera 41 shown in FIG. 13 may hold the variable focal length lens device 100 in a detachable manner, or may be formed integrally with the variable focal length lens device 10. The camera 10 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 Lens barrel member 2,102 Mount member 3 Long hole 10,100 Variable focal length lens apparatus 21,121 First drive mechanism 22,122 Second drive mechanism 23,123 First support member 24,124 First 2 support members 31 operation members 32, 132 focal length detection means 34, 134 storage means 35, 135 control means 41 imaging device (camera)
43 quick return mirror 44 focusing screen 45 pentaprism 46 eyepiece 47 image sensor 125 third drive mechanism 126 third support member 136 switch member 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

Claims (14)

A lens barrel;
A holding member for holding a plurality of lens groups in the lens barrel;
Independent driving means for respectively moving at least three moving lens groups of the plurality of lens groups along the optical axis;
An operation unit for changing the focal length;
A focal length detection means for detecting the focal length changed by the operation unit;
Memory means for storing the position change of position relative to the prior SL designed value on the optical axis of at least two respective moving lens unit wide angle end state of the moving lens group for each of the focal length,
Based on the focal length information detected by the focal length detection means, the moving lens is moved to a position on the optical axis via the driving means based on the position change of the at least two moving lens groups. Control means for positioning each group;
A variable focal length lens device comprising:   2. The variable focal length according to claim 1, wherein the storage unit stores the change in position of each of the at least two moving lens groups having the best imaging performance at each focal length. Lens device.   The variable focal length lens apparatus according to claim 1, wherein the storage unit is rewritable.   4. The operation unit according to claim 1, wherein the operation unit moves at least one moving lens group of the moving lens groups along an optical axis through the independent driving unit. 5. Variable focal length lens device.   5. The variable focal length lens device according to claim 1, wherein the operation unit is an operation ring that is disposed on an outer peripheral portion of the lens barrel and is rotatable about the optical axis. 6. .   5. The variable focal length lens device according to claim 1, wherein the operation unit is a switch disposed on an outer peripheral portion of the lens barrel. 6.   7. The variable focal length lens device according to claim 1, further comprising a mount member attached to and detached from the camera at one end of the lens barrel. The plurality of lens groups are, 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. And a fifth lens group having positive refractive power, substantially consisting of five lens groups,
The at least three moving lens groups include the second lens group, the fourth lens group, and the fifth lens group,
8. The variable focal length lens device according to claim 1, wherein the at least two moving lens groups include the fourth lens group and the fifth lens group. 9.   The variable according to claim 8, wherein the operation unit moves at least one of the second lens group, the fourth lens group, and the fifth lens group via the independent driving unit. Focal length lens device.   9. The operation unit according to claim 8, wherein the operation unit is an operation ring disposed on an outer peripheral part of a lens barrel and rotatable around an optical axis, and moves the second lens group via the driving unit. Variable focal length lens device.   The operation unit is a switch disposed on an outer periphery of a lens barrel, and moves the second lens group, the fourth lens group, and the fifth lens group via the driving unit. The variable focal length lens device according to claim 8.   An imaging apparatus comprising the variable focal length lens device according to any one of claims 1 to 11. A lens barrel;
A holding member for holding a plurality of lens groups in the lens barrel;
Independent driving means for respectively moving at least three moving lens groups of the plurality of lens groups along the optical axis;
An operation unit for changing the focal length;
A focal length detection means for detecting the focal length changed by the operation unit;
Memory means for storing the position change of position relative to the prior SL designed value on the optical axis of at least two respective moving lens unit wide angle end state of the moving lens group for each of the focal length,
Control means for controlling the drive means,
Based on the focal length information detected by the focal length detection means, the control means moves the at least two moving lens groups on the optical axis via the driving means based on the position changes. A method for adjusting a variable focal length lens apparatus, wherein each of the movable lens groups is positioned at a position. The plurality of lens groups are, 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. And a fifth lens group having positive refractive power, substantially consisting of five lens groups,
The at least three moving lens groups include the second lens group, the fourth lens group, and the fifth lens group,
The method of adjusting a variable focal length lens apparatus according to claim 13, wherein the at least two moving lens groups include the fourth lens group and the fifth lens group.

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