JP2004318107A - Zoom lens device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a zoom lens device suitable for a digital camera equipped with a zoom lens system which is bright even in the longest focal distance state though a zoom ratio is large, and whose length in an optical axis direction in housing is very short. <P>SOLUTION: In the zoom lens device equipped with the zoom lens system and an imaging device for converting an optical image formed by the zoom lens system into electric image data in order from an object side, the zoom lens system is constituted of a 1st group having negative power, a 2nd group having positive power, a 3rd group having positive power and a 4th group in order from the object side. In the case of zooming from the shortest focal distance state to the longest focal distance state, space between the respective groups is changed by moving the 2nd and the 3rd groups, especially, moving the 2nd group to the object side, and focusing in accordance with the change of an object distance is performed by moving the 3rd group. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a CCD (Charge Coupled Device) and a CMOS sensor (Complementary
The present invention relates to a zoom lens device having an image pickup device for converting an optical image formed on a light receiving surface such as a metal-oxide semiconductor (complementary metal oxide semiconductor sensor) into an electric signal, and in particular, a small zoom lens having a zoom lens system. Equipment related.

2. Description of the Related Art In recent years, a digital camera that converts an optical image into an electric signal by using an imaging device such as a CCD or a CMOS sensor instead of a silver halide film, digitizes the data, and records or transfers the digital image has become popular. In such digital cameras, CCD and CMOS sensors having high pixels such as 2 million pixels and 3 million pixels have recently been provided at relatively low cost.
The demand for a high-performance zoom lens device equipped with a high-pixel image sensor has been greatly increased. Among these zoom lens devices, in particular, a compact zoom lens device equipped with a zoom lens system capable of zooming without deteriorating image quality has been desired.

In recent years, with the improvement of image processing capability of semiconductor devices and the like, personal computers, mobile computers, mobile phones, and personal digital assistants (PDAs) have been developed.
ce) and the like, a zoom lens device is built in or externally attached, which has spurred demand for a high-performance zoom lens device.

As a zoom lens system used in such a zoom lens device, a number of so-called minus-lead zoom lens systems have been proposed in which the group arranged closest to the object side has negative power. The minus lead zoom lens system has features such as easy widening of the angle and easy securing of a lens back necessary for insertion of an optical low-pass filter.

As a minus lead zoom lens system, there is a zoom lens system conventionally proposed as a photographing lens system of a camera for a silver halide film. However, in these zoom lens systems, in particular, the exit pupil position of the lens system in the shortest focal length state is relatively close to the image plane,
In particular, there is a problem that the pupil of the microlens provided corresponding to each pixel of the image sensor having a high number of pixels does not match, and a sufficient amount of peripheral light cannot be secured. In addition, since the exit pupil position fluctuates greatly at the time of zooming, there is also a problem that it is difficult to set the pupil of the micro lens. Also,
In the first place, the required optical performance such as spatial frequency characteristics is completely different between the silver halide film and the imaging device, and thus sufficient optical performance required for the imaging device cannot be secured. Therefore, there is a need to develop a dedicated zoom lens system optimized for a zoom lens device having an image sensor.

As a minus lead zoom lens system for a zoom lens device having an imaging device, for example, US Pat. No. 5,745,301 discloses a two-component zoom composed of a first group of negative power and a second group of positive power. A lens system is disclosed.

Japanese Patent Application Laid-Open No. 1-191820 discloses a first group of negative power, a second group of positive power, and a third group of positive power.
A three-component zoom lens system for a video camera comprising a group is disclosed.

Japanese Patent Application Laid-Open No. 1-216310 discloses a first group of negative power, a second group of positive power, and a third group of negative power.
There is disclosed a zoom lens system for a video camera having a four-component configuration including a group and a fourth group having a positive power.

Further, Japanese Patent Application Laid-Open No. Hei 9-79026 discloses a zoom lens for an electronic still camera having a four-component configuration including a first group of negative power, a second group of positive power, a third group of negative power, and a fourth group of positive power. A system is disclosed.

U.S. Pat.No. 5,745,301

JP-A 1-191820 JP-A 1-216310 JP-A-9-79026

However, the above-mentioned U.S. Patent No. 5,745,301, JP-A-1-191820 or JP-A-1-21631
The zoom lens system disclosed in No. 0 has a problem that the zoom ratio is about twice and the zoom ratio is small.

Further, the zoom lens system disclosed in Japanese Patent Application Laid-Open No. 9-179026 has a zoom ratio of about three times, but has a problem that the F-number in the longest focal length state is as large as 7 and is not a bright zoom lens system. there were.

Further, each zoom lens system requires a large number of lens elements, and has a problem that it lacks compactness, particularly compactness in the optical axis direction when stored (when retracted).

SUMMARY OF THE INVENTION It is an object of the present invention to provide a zoom lens device including a zoom lens system having a sufficiently short length in the optical axis when stored, despite a large zoom ratio.

A further object of the present invention is to provide a zoom lens device including a zoom lens system that is bright even in the longest focal length state and has a sufficiently small length in the optical axis direction when housed.

In order to achieve the above object, the zoom lens system according to claim 1 includes, in order from the object side, a zoom lens system, and an image sensor that converts an optical image formed by the zoom lens system into electrical image data. Wherein the zoom lens system includes, in order from the object side, a first unit having negative power, a second unit having positive power, and a third unit having positive power.
A second group and a fourth group. When zooming from the shortest focal length state to the longest focal length state, the second and third groups are moved, and in particular, the second group is moved to the object side. In addition to changing the distance, focusing according to the change in the object distance is performed by moving the third lens unit.

Another aspect of the present invention is a digital camera including the zoom lens device. In the past, the term digital camera used to refer exclusively to those that record optical still images, but those that can simultaneously handle moving pictures and digital video cameras for home use have also been proposed, and at present there is no particular distinction between them. It is getting better. Therefore, the term digital camera used in this specification refers to a digital still camera, a digital movie camera, a web camera (
An open or private camera connected to a network that can transmit and receive images regardless of whether it is connected directly to the network or via a device having an information processing function such as a personal computer. And cameras connected to the optical device, and includes an image pickup device having an image pickup device that converts an optical image formed on a light receiving surface into an electric signal.

Another aspect of the present invention is a portable information device including the zoom lens device. Here, the portable information device is a mobile phone terminal or a PDA (Personal Digital Assistan
It means a small and portable information device terminal for personal use such as t).

As described above, according to the zoom lens device of the present invention, there is provided a zoom lens device including a zoom lens system having a sufficiently small length in the optical axis direction when housed, despite a large zoom ratio. can do.

Further, according to the zoom lens device of the present invention, it is possible to provide a zoom lens device including a zoom lens system which is bright even in the longest focal length state and has a sufficiently small length in the optical axis direction when housed.

    Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 16, for example, an imaging apparatus according to an embodiment of the present invention includes a zoom lens system, a TL, and an optical low-pass filter that sequentially form an optical image of an object in a variable order from the object side (subject side). It comprises an LPF and an image sensor SR for converting an optical image formed by the zoom lens system TL into an electric signal. The imaging device is a digital camera; a video camera; a personal computer, a mobile computer, a mobile phone, and a personal digital assistant (PDA).
l Assistance) is a main component of a camera that is built in or externally attached.

The optical low-pass filter LPF has a specific cutoff frequency for adjusting the spatial frequency characteristics of the taking lens system and eliminating color moiré generated in the image sensor. The optical low-pass filter according to the embodiment is a birefringent low-pass filter formed by laminating a birefringent material such as quartz whose crystal axis is adjusted in a predetermined direction, a wave plate that changes the plane of polarization, and the like. Note that, as the optical low-pass filter, a phase-type low-pass filter or the like that achieves the required optical cutoff frequency characteristic by the diffraction effect may be employed.

The image sensor SR is composed of a CCD having a plurality of pixels, and converts an optical image formed by a zoom lens system into a CCD.
Convert to an electric signal with CD. The signal generated by the image sensor SR is subjected to predetermined digital image processing and image compression processing as required, and is recorded as digital video signals in a memory (semiconductor memory, optical disk, etc.). The signal is transmitted to another device through the device or converted into an infrared signal. Note that instead of a CCD, a CMOS sensor (Complementary M
etal-oxide Semiconductor) may be used.

FIG. 1 is a lens configuration diagram illustrating a configuration of a zoom lens system according to the first embodiment. The zoom lens system includes, in order from the object side, a first group Gr1 including a biconcave first lens L1 and a positive meniscus second lens L2 convex on the object side, and a biconvex third lens L3, a second lens unit Gr2 including a negative meniscus fourth lens L4 having a concave surface facing the object side and an aperture ST, and a third lens unit Gr3 including only a biconvex fifth lens L5. A fourth lens unit Gr4 including only a positive meniscus sixth lens L6 with the convex surface facing the object side in the axial direction. During zooming from the shortest focal length state to the longest focal length state, the first group Gr1 moves while drawing a locus of a U-turn convex on the image side, and the second group Gr2 and the third group Gr3 narrow each other's distance. The fourth unit Gr4 is fixed with respect to the image plane while moving monotonously to the object side. In focusing from an infinity in-focus condition to a finite object in-focus condition, the fifth lens L5 is independently moved to the object side.

FIG. 2 is a lens configuration diagram illustrating a configuration of a zoom lens system according to a second embodiment. The zoom lens system includes, in order from the object side, a first group Gr1 including only a biconcave first lens L1,
A second group Gr2 composed of an aperture ST, a biconvex second lens L2, a biconcave third lens L3 and a biconvex fourth lens L4, a biconvex fifth lens L5 and an object side A third group Gr3 composed of a negative meniscus sixth lens L6 with a concave surface facing the fourth group Gr4 composed of only a negative meniscus seventh lens L7 with a concave surface facing the object side. Become. During zooming from the shortest focal length state to the longest focal length state, the first group Gr1 moves while drawing a locus of a U-turn convex to the image side, the second group Gr2 moves monotonously to the object side, and the third group Gr2. Gr3 moves while drawing a locus convex toward the object side, while the fourth unit Gr4 is fixed with respect to the image plane. In focusing from an infinity in-focus condition to a finite object in-focus condition, the entire third unit Gr3 is moved to the object side.

FIG. 3 is a lens configuration diagram illustrating a configuration of a zoom lens system according to a third embodiment. The zoom lens system includes, in order from the object side, a first group Gr1 including a biconcave first lens L1 and a positive meniscus second lens L2 convex on the object side, an aperture ST, and a biconvex shape. A second group Gr2 including a third lens L3, a biconcave fourth lens L4, and a biconvex fifth lens L5, and a biconvex sixth lens L6
A third unit Gr3 including only a negative meniscus seventh lens L7 having a concave surface facing the object side; During zooming from the shortest focal length state to the longest focal length state, the first group Gr1 moves while drawing a locus of a U-turn convex to the image side, the second group Gr2 moves monotonously to the object side, and the third group Gr2. Gr3 moves to the image side, while the fourth unit Gr4 is fixed with respect to the image plane. In focusing from an infinity in-focus condition to a finite object in-focus condition, the sixth lens L6 is independently moved to the object side.

FIG. 4 is a lens configuration diagram illustrating a configuration of a zoom lens system according to a fourth embodiment. The zoom lens system includes, in order from the object side, a first group Gr1 including a biconcave first lens L1 and a positive meniscus second lens L2 convex on the object side, an aperture ST, and a convex surface on the object side. A second lens group Gr2 including a positive meniscus third lens L3, a biconcave fourth lens L4, and a biconvex fifth lens L5, and a biconvex sixth lens and a biconcave The third lens unit includes a third lens unit Gr3 including a seventh lens L7 and a fourth lens unit Gr4 including only a negative meniscus eighth lens L8 having a concave surface facing the object side. During zooming from the shortest focal length state to the longest focal length state, the first group Gr1 moves while drawing a locus of a U-turn convex on the image side, the second group Gr2 moves monotonously to the object side, and the third group Gr2. Gr3 moves monotonously to the image side, while the fourth unit Gr4 is fixed with respect to the image plane. In focusing from an infinity in-focus condition to a finite object in-focus condition, the entire third unit Gr3 is moved to the object side.

FIG. 5 is a lens configuration diagram illustrating a configuration of a zoom lens system according to a fifth embodiment. The zoom lens system includes, in order from the object side, a first group Gr1 including a biconcave first lens L1 and a positive meniscus second lens L2 convex on the object side, an aperture ST, and a convex surface on the object side. A second lens unit Gr2 including a positive meniscus third lens L3 facing the lens, a negative meniscus fourth lens L4 having a convex surface facing the object side, and a biconvex fifth lens L5, and a biconvex sixth lens L2. Lens L6 and biconcave seventh lens L
And a fourth group Gr4 including only a negative meniscus eighth lens L8 having a concave surface facing the object side. During zooming from the shortest focal length state to the longest focal length state, the first group Gr1 moves while drawing a locus of a U-turn convex to the image side, the second group Gr2 moves monotonously to the object side, and the third group Gr2. Gr3 moves while drawing a locus of U-turn convex to the object side, while the fourth group Gr4
Is fixed with respect to the image plane. In focusing from an infinity in-focus condition to a finite object in-focus condition, the third unit Gr3 is moved to the object side.

The zoom lens system according to each embodiment includes, in order from the object side, a first unit having negative power, a second unit having positive power, a third unit having positive power, and a fourth unit. The zoom lens system is configured to move the second and third units, and in particular, move the second unit toward the object side to change the distance between the units during zooming from the shortest focal length state to the longest focal length state. . During zooming of the zoom lens system with the above configuration, particularly from the shortest focal length state to the longest focal length state, the second and third units are moved, and in particular, the second unit is moved toward the object side to change the distance between the units. By adopting the configuration, it is possible to satisfactorily correct spherical aberration, particularly spherical aberration generated in the longest focal length state, as compared with a negative, positive, and positive three-component system.

Each zoom lens system performs focusing according to a change in the object distance by moving the third lens unit. Usually, when the second lens unit is moved to the object side during focusing according to the change in the object distance, negative field curvature occurs due to strong positive power. Therefore, by moving the third lens group having relatively weak power, it is possible to suppress the occurrence of the field curvature. Further, when the moving group at the time of focusing is the third group, the lens elements are lighter than the second group, so that the load on the drive system can be reduced and the mechanical structure can be easily held. Become.

It is preferable that the fourth unit has a positive power, since it becomes easy to secure an incident angle of an off-axis ray to the image plane particularly in the shortest focal length state, and the image plane illuminance can be maintained.

In addition, it is preferable that the fourth unit has a negative power because the total length can be reduced and a compact zoom lens system can be achieved.

  The zoom lens system according to each embodiment satisfies the following conditions.

0.5 <f2 / f3 <2.5 (1)
However,
f2: focal length of the second group,
f3: focal length of the third group,
It is.

Conditional expression (1) defines the ratio of the second and third groups. If the lower limit of the conditional expression is exceeded, the power of the third lens unit will be too large, and it will be difficult to balance with the under spherical aberration generated in the second lens unit. On the other hand, when the value exceeds the upper limit, the power of the third lens unit becomes too small, and the outer diameter of the second lens unit becomes too large, which is not preferable.

In the zoom lens system according to each of the embodiments, it is preferable that the zoom lens system include a first group that is disposed closest to the object side and includes only one negative lens element. Normally, in a zoom lens in which the first group has negative power, the lens diameter of the first group in the direction perpendicular to the optical axis is the largest in order to secure the F-number. Here, if the first group is composed of a plurality of lens elements, the effective diameter of the lens elements of the first group will be large in order to secure light rays incident on the zoom lens system. Therefore, in order to reduce the outer diameter, it is desirable to configure the sheet with a minimum number of one sheet. Further, when a lens element having a large lens diameter has a curvature, the on-axis air gap between the lens elements increases accordingly. That is, the number of lenses in the first group is an important factor for increasing the overall length of the zoom lens system. In the zoom lens system according to each of the embodiments, since the negative lens group is constituted by one of the minimum number of components, the total length of the zoom lens system is reduced, and the thickness of the zoom lens system in a retracted state (hereinafter referred to as collapsed state). Can be reduced.

In the zoom lens system of each embodiment, it is preferable that the first group is composed of two lenses, because lateral chromatic aberration in the shortest focal length state can be favorably corrected.

It is desirable that the first unit moves while drawing a locus convex toward the image side during zooming, as in the zoom lens systems of the embodiments. By moving in this way, it is possible to satisfactorily correct the field curvature in the intermediate focal length state.

When the fourth unit adopts a configuration fixed to the image plane during zooming,
This is preferable because the lens barrel configuration can be simplified.

Each of the lens groups constituting the first to fifth embodiments described above includes only a refraction lens that deflects an incident light beam by refraction, but is not limited thereto. For example, each lens group may be composed of a diffractive lens that deflects an incident light beam by diffraction, a hybrid refraction / diffraction lens that deflects an incident light beam by a combination of a diffraction action and a refraction action, or the like.

Further, a reflecting member that bends the incident optical axis may be added by appropriately adjusting the air gap existing in each lens group or between the lens groups. Bending the incident optical axis is preferable because the degree of freedom of arrangement of the optical system can be improved and the thickness of the optical device in the direction of the incident optical axis can be reduced.

Hereinafter, the configuration of the zoom lens embodying the present invention will be described more specifically with reference to construction data, aberration diagrams, and the like. In addition, Examples 1 to 5 listed below are the first to fifth examples described above.
Lens configuration diagrams respectively corresponding to the fifth embodiment and representing the first to fifth embodiments
(Figures 1 to 5 http://www.ipdl.jpo-miti.go.jp/Tokujitu/tjitemdrw.ipdl?N0000=231&N05
00 = 1E_N /; >>=;=>: 6 /// & N0001 = 148 & N0552 = 9 & N0553 = 000012) shows the corresponding lens configurations of Examples 1 to 5, respectively.

In the construction data of each embodiment, ri (i = 1, 2, 3, ...) is the radius of curvature of the i-th surface counted from the object side, di (i = 1, 2, 3, ...) Indicates the i-th axial distance from the object side, and Ni (i = 1,2,3, ...) and νi (i = 1,2,3, ...) The refractive index (Nd) and Abbe number (νd) of the i-th optical element counted for the d-line are shown. In the construction data, the axial top surface interval (variable interval) that changes during zooming is from the shortest focal length state (short focal length end) [W] to the middle (intermediate focal length state) [M] to the longest focal length state (long). Focal length end) [T]
Is the axial air spacing between each lens group. The focal length f and the F-number FNO of the entire system corresponding to each focal length state [W], [M], [T] are also shown.

A surface with * added to the radius of curvature ri indicates a surface constituted by an aspheric surface, and is defined by the following formula (AS) representing the surface shape of the aspheric surface. The aspherical surface data of each example is shown together with other data.

Z (h) = r- (r ^ 2-ε ・ h ^ 2) ^ 1/2 + (A4 ・ h ^ 4 + A6 ・ h ^ 6 + A8 ・ h ^ 8 + ...) (AS)
r: radius of paraxial curvature of aspheric surface
ε: elliptic coefficient,
Ai: the i-th aspherical coefficient of the aspherical surface,

<Example 1>
f = 5.8-11.1-16.8 mm
FNo. = 2.95-3.81-4.83
[Curvature radius] [Shaft upper surface interval] [Refractive index (Nd)] [Abbe number]
r1 * = -39.975
d1 = 1.200 N1 = 1.55299 ν1 = 62.75
r2 * = 6.541
d2 = 0.755
r3 = 8.756
d3 = 1.873 N2 = 1.84666 ν2 = 23.78
r4 = 11.530
d4 = 18.755-5.409-0.900
r5 = 9.844
d5 = 4.269 N3 = 1.75291 ν3 = 51.62
r6 = -12.759
d6 = 1.000
r7 = -7.836
d7 = 1.000 N7 = 1.84666 ν4 = 23.78
r8 = -37.579
d8 = 1.000
r9 = ∞
d9 = 7.471-6.059-4.273
r10 * = 12.663
d10 = 1.741 N8 = 1.48749 ν5 = 70.44
r11 * = -32.883
d11 = 2.344-9.246-15.779
r12 * = 6.386
d12 = 1.599 N9 = 1.52510 ν6 = 56.38
r13 * = 8.384
d13 = 0.993
r14 = ∞
d14 = 2.000 N10 = 1.51680 ν7 = 64.20
r15 = ∞

[Aspheric coefficient]
r1
ε = 1.0000E + 00
A4 = 2.2080E-05
A6 = -8.1895E-06
A8 = 2.0365E-07
A10 = -1.1961E-09

r2
ε = 1.0000E + 00
A4 = -3.4828E-04
A6 = -1.4369E-05
A8 = 1.1602E-07
A10 = 2.6586E-10

r10
ε = 1.0000E + 00
A4 = 4.1991E-05
A6 = 3.4463E-06
A8 = -2.2840E-06
A10 = 1.4597E-07

r11
ε = 1.0000E + 00
A4 = 1.6750E-04
A6 = 8.2009E-06
A8 = -2.6592E-06
A10 = 1.5482E-07

r12
ε = 1.0000E + 00
A4 = 1.7501E-04
A6 = -9.2028E-05
A8 = -4.5108E-06
A10 = -5.1235E-08

r13
ε = 1.0000E + 00
A4 = 2.3030E-03
A6 = -2.3547E-04
A8 = -1.1690E-05
A10 = 5.0795E-07

<Example 2>
f = 5.8-10.4-16.6 mm
FNo. = 2.95-3.19-3.91
[Curvature radius] [Shaft upper surface interval] [Refractive index (Nd)] [Abbe number]
r1 * = -145.113
d1 = 1.000 N1 = 1.49310 ν1 = 83.58
r2 * = 7.808
d2 = 21.602-7.045-2.000
r3 = ∞
d3 = 0.600
r4 = 6.092
d4 = 2.735 N2 = 1.73480 ν2 = 47.86
r5 = -21.758
d5 = 1.541
r6 * = -7.582
d6 = 1.000 N3 = 1.84666 ν3 = 23.82
r7 * = 13.430
d7 = 3.942
r8 = 19.767
d8 = 2.520 N4 = 1.85000 ν4 = 40.04
r9 = -17.304
d9 = 1.000-4.384-11.701
r10 = 19.300
d10 = 2.861 N5 = 1.48749 ν5 = 70.44
r11 = -6.950
d11 = 0.100
r12 = -6.755
d12 = 0.800 N6 = 1.58340 ν6 = 30.23
r13 = -12.658
d13 = 1.073
r14 = -8.000
d14 = 0.800 N7 = 1.79850 ν7 = 22.60
r15 = -19.187
d15 = 0.425
r16 = ∞
d16 = 2.000 N8 = 1.51633 ν8 = 64.14
r17 = ∞
[Aspheric coefficient]
r1
ε = 1.0000E + 00
A4 = -8.4261E-04
A6 = 3.4843E-05
A8 = -5.3266E-07
A10 = 2.8481E-09

r2
ε = 1.0000E + 00
A4 = -1.2797E-03
A6 = 3.4368E-05
A8 = 1.0424E-07
A10 = -1.1871E-08

r6
ε = 1.0000E + 00
A4 = -4.0212E-04
A6 = 1.0262E-05
A8 = 7.3123E-06
A10 = -4.4336E-07

r7
ε = 1.0000E + 00
A4 = 6.2524E-04
A6 = 5.7678E-05
A8 = 1.6430E-06
A10 = -5.4369E-08

r13
ε = 1.0000E + 00
A4 = 3.5743E-04
A6 = -1.0838E-05
A8 = 2.8869E-07
A10 = -3.0988E-09

<Example 3>
f = 5.4-10.6-20.5 mm
FNo. = 2.95-3.59-5.05
[Curvature radius] [Shaft upper surface interval] [Refractive index (Nd)] [Abbe number]
r1 * = -62.388
d1 = 1.000 N1 = 1.67246 ν1 = 54.84
r2 * = 7.517
d2 = 2.033
r3 = 12.124
d3 = 2.242 N2 = 1.84666 ν2 = 23.78
r4 = 22.671
d4 = 26.346-8.841-1.000
r5 = ∞
d5 = 0.600
r6 = 8.414
d6 = 2.572 N3 = 1.75450 ν3 = 51.57
r7 = -214.826
d7 = 1.586
r8 * = -41.141
d8 = 1.000 N4 = 1.84666 ν4 = 23.82
r9 * = 12.338
d9 = 3.742
r10 = 19.804
d10 = 2.692 N5 = 1.56021 ν5 = 62.10
r11 = -14.550
d11 = 1.000
r12 * = 27.714
d12 = 1.409 N6 = 1.52510 ν6 = 56.38
r13 * = -51.224
d13 = 5.642
r14 = -9.076
d14 = 0.800 N7 = 1.58340 ν7 = 30.23
r15 = -14.938
d15 = 0.336
r16 = ∞
d16 = 2.000 N8 = 1.51633 ν8 = 64.14
r17 = ∞

[Aspheric coefficient]
r1
ε = 1.0000E + 00
A4 = 5.2949E-05
A6 = 2.4146E-06
A8 = -5.3199E-08
A10 = 3.0717E-10

r2
ε = 1.0000E + 00
A4 = -1.7266E-04
A6 = -5.2034E-07
A8 = 6.9605E-08
A10 = -3.3443E-09

r8
ε = 1.0000E + 00
A4 = 2.3478E-05
A6 = 5.5834E-06
A8 = -2.3522E-07
A10 = 3.5749E-09

r9
ε = 1.0000E + 00
A4 = 4.8852E-04
A6 = 1.5183E-05
A8 = -5.4123E-07
A10 = 2.2280E-08

r12
ε = 1.0000E + 00
A4 = -2.4043E-05
A6 = 1.3756E-05
A8 = -7.5488E-07
A10 = 4.3195E-08

r13
ε = 1.0000E + 00
A4 = 1.1110E-04
A6 = 4.2505E-06
A8 = -2.9448E-07
A10 = 4.0091E-08

<Example 4>
f = 5.6-10.9-21.2 mm
FNo. = 2.95-3.69-5.47
[Curvature radius] [Shaft upper surface interval] [Refractive index (Nd)] [Abbe number]
r1 * = -2206.921
d1 = 1.000 N1 = 1.70830 ν1 = 52.37
r2 * = 7.541
d2 = 2.035
r3 = 10.756
d3 = 2.244 N2 = 1.84666 ν2 = 23.78
r4 = 17.416
d4 = 23.473-7.610-1.000
r5 = ∞
d5 = 0.600
r6 = 8.203
d6 = 2.459 N3 = 1.78862 ν3 = 46.42
r7 = 35.013
d7 = 1.000
r8 * = -105.219
d8 = 1.000 N4 = 1.84666 ν4 = 23.82
r9 * = 11.626
d9 = 2.285
r10 = 20.288
d10 = 2.753 N5 = 1.57612 ν5 = 60.77
r11 = -13.148
d11 = 1.019-8.431-25.158
r12 = 21.425
d12 = 2.229 N6 = 1.82241 ν6 = 42.56
r13 = -15.290
d13 = 0.100
r14 = -15.623
d14 = 0.800 N7 = 1.58340 ν7 = 30.23
r15 = 22.445
d15 = 6.051-5.837-1.993
r16 = -8.000
d16 = 0.800 N8 = 1.79850 ν8 = 22.6
r17 = -8.795
d17 = 0.100
r18 = ∞
d18 = 2.000 N9 = 1.51633 ν9 = 64.14
r19 = ∞

[Aspheric coefficient]
r1
ε = 1.0000E + 00
A4 = 3.9901E-05
A6 = 3.3171E-06
A8 = -6.0759E-08
A10 = 3.0895E-10

r2
ε = 1.0000E + 00
A4 = -1.1359E-04
A6 = 9.2923E-07
A8 = 1.2155E-07
A10 = -4.1825E-09

r8
ε = 1.0000E + 00
A4 = 4.2490E-05
A6 = 1.1312E-05
A8 = -6.0790E-07
A10 = 1.4669E-08

r9
ε = 1.0000E + 00
A4 = 4.3056E-04
A6 = 1.8279E-05
A8 = -9.5543E-07
A10 = 3.2601E-08

r15
ε = 1.0000E + 00
A4 = 2.4936E-04
A6 = -1.4428E-05
A8 = 1.0190E-06
A10 = -2.5304E-08

<Example 5>
f = 5.4-11.9-25.6 mm
FNo. = 2.95-3.69-5.47
[Curvature radius] [Shaft upper surface interval] [Refractive index (Nd)] [Abbe number]
r1 * = -212.663
d1 = 1.000 N1 = 1.74449 ν1 = 51.91
r2 * = 8.320
d2 = 1.820
r3 = 11.906
d3 = 2.346 N2 = 1.84666 ν2 = 23.78
r4 = 20.694
d4 = 29.376-8.154-1.307
r5 = ∞
d5 = 0.600
r6 = 8.903
d6 = 2.426 N3 = 1.75450 ν3 = 51.57
r7 = 44.059
d7 = 1.023
r8 * = 91.082
d8 = 1.000 N4 = 1.84666 ν4 = 23.82
r9 * = 12.588
d9 = 4.473
r10 = 22.161
d10 = 2.756 N5 = 1.49756 ν5 = 69.00
r11 = -16.983
d11 = 1.212
r12 = 18.148
d12 = 2.161 N6 = 1.75450 ν6 = 51.57
r13 = -21.315
d13 = 0.100
r14 = -29.569
d14 = 0.800 N7 = 1.58340 ν7 = 30.23
r15 * = 23.902
d15 = 5.780
r16 = -10.181
d16 = 0.800 N8 = 1.84923 ν8 = 34.60
r17 = -14.581
d17 = 0.331
r18 = ∞
d18 = 2.000 N9 = 1.51633 ν9 = 64.14
r19 = ∞

[Aspheric coefficient]
r1
ε = 1.0000E + 00
A4 = 5.8268E-05
A6 = 7.7325E-07
A8 = -1.9659E-08
A10 = 1.0309E-10

r2
ε = 1.0000E + 00
A4 = -9.1108E-05
A6 = 7.2884E-08
A8 = 1.4570E-08
A10 = -1.1004E-09

r8
ε = 1.0000E + 00
A4 = 8.2459E-05
A6 = 1.1732E-05
A8 = -6.4586E-07
A10 = 1.2445E-08

r9
ε = 1.0000E + 00
A4 = 3.7619E-04
A6 = 1.8914E-05
A8 = -8.9674E-07
A10 = 2.2738E-08

r15
ε = 1.0000E + 00
A4 = 2.1626E-04
A6 = -1.1901E-05
A8 = 7.7472E-07
A10 = -1.6905E-08

6 to 15 are aberration diagrams of Examples 1 to 5, FIGS. 6 to 10 are aberrations of Examples 1 to 5 in an infinity in-focus state, and FIGS. 9 shows respective aberrations of Examples 1 to 5 in a focused state of a close object (object distance of 40 cm). In each aberration diagram, the upper part shows the shortest focal length state, the middle part shows the middle, and the lower part shows various aberrations in the longest focal state (from left to right, spherical aberration, astigmatism,
Distortion (Y ': image height). Further, the solid line (d) and the dashed-dotted line (g) in the spherical aberration diagram represent the spherical aberration with respect to the d-line and the g-line, respectively, and the dashed line (SC) represents the sine condition.
) And the solid line (DS) represent the astigmatism with respect to the d-line on the meridional surface and the sagittal surface, respectively.

1 is a lens configuration diagram illustrating a first embodiment (Example 1) of the present invention. FIG. 4 is a lens configuration diagram illustrating a second embodiment (Example 2) of the present invention. Lens configuration diagram showing a third embodiment (Example 3) of the present invention A lens configuration diagram illustrating a fourth embodiment (Example 4) of the present invention. A lens configuration diagram illustrating a fifth embodiment (Example 5) of the present invention. Aberration diagram of the first embodiment (Example 1) of the present invention when focused on infinity Aberration diagram of the second embodiment (Example 2) of the present invention when focused on infinity Aberration diagram of the third embodiment (Example 3) of the present invention when focused on infinity Aberration diagram of the fourth embodiment (Example 4) of the present invention in an infinity in-focus state Aberration diagram of the fifth embodiment (Example 5) of the present invention when focused on infinity Aberration diagram of the first embodiment (Example 1) of the present invention when a close object is in focus Aberration diagram of the second embodiment (Example 2) of the present invention in a state where a close object is in focus Aberration diagram of the third embodiment (Example 3) of the present invention when a close object is in focus 4A and 4B are aberration diagrams of a fourth embodiment (Example 4) of the present invention in a state where a close object is in focus. Aberration diagram of the fifth embodiment (Example 5) of the present invention in a state where a close object is in focus FIG. 1 is a diagram showing a schematic configuration of a zoom lens device according to the present invention.

Explanation of reference numerals

Zoom lens system (TL)
First lens group (Gr1)
Second lens group (Gr2)
Third lens group (Gr3)
4th lens group (Gr4)
Filter (LPF)
Image sensor (SR)

Claims (7)

A zoom lens device including, in order from the object side, a zoom lens system, and an imaging element that converts an optical image formed by the zoom lens system into electrical image data,
The zoom lens system includes, in order from the object side, a first group having negative power, a second group having positive power, a third group having positive power, and a fourth group,
At the time of zooming from the shortest focal length state to the longest focal length state, the second and third lens groups are moved, and in particular, the second lens group is moved to the object side to change the distance between the lens groups,
A zoom lens apparatus, wherein focusing according to a change in an object distance is performed by moving the third group. 2. The zoom lens device according to claim 1, wherein the fourth group has a positive power. The zoom lens apparatus according to claim 1, wherein the fourth group has a negative power. The zoom lens device according to claim 1, wherein the following condition is satisfied;
0.5 <f2 / f3 <2.5
However,
f2: focal length of the second group,
f3: focal length of the third group,
It is. 2. The zoom lens according to claim 1, wherein the fourth lens unit is fixed to an image plane during zooming.
The zoom lens device according to any one of the preceding claims. A digital camera comprising the zoom lens device according to claim 1. A portable information device comprising the zoom lens device according to claim 1.

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