JP2004318103A - 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 consists of a plurality of groups including a 1st group arranged nearest to the object side and having negative power and a 2nd group including a positive lens element and a negative lens element independent respectively and having positive power as a whole, and all the respective lens surfaces constituting the zoom lens system are refractive surfaces and zooming is performed by changing space between respective groups. The zoom lens system satisfies a specified conditional expression. <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 a first lens unit disposed closest to the object side and having a negative power, a lens element having a positive power, and a lens element having a negative power. The zoom lens system is composed of a plurality of groups including a second group having power.Each lens surface constituting the zoom lens system is a refracting surface, and zooming is performed by changing an interval between the respective groups. To be satisfied.

2.3 ≤ fw / ft ≤ 5.5
0.1 <T23w / fw <1.5
0.6 <Tsum / fw <1.8
However,
fw: focal length of the zoom lens system in the shortest focal length state,
ft: focal length of the zoom lens system in the longest focal length state,
T23w: axial top surface distance between the second group and the group adjacent to the image side in the shortest focal length state,
Tsum: Sum of the thicknesses of all the lens elements included in the zoom lens system,
It is.

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.

For example, as shown in FIG. 15, 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 form an optical image of an object so as to be variable in 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 unit 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 first cemented lens DL1 formed by cementing a third lens L3 and a biconcave fourth lens, and a second lens unit Gr2 including a positive meniscus fifth lens L5 having a convex surface facing the object side. A third lens unit Gr3 including only a negative meniscus sixth lens L6 having a concave 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 lens unit Gr1 moves while drawing a locus of a U-turn convex to the image side, and the second lens unit Gr2 moves monotonously to the object side, respectively. The third lens unit Gr3 is fixed to the image plane. 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,
The second lens L2 is composed of a biconvex second lens L2, a stop ST and a paraxially biconcave third lens L3.
A second lens unit Gr2, a third lens unit Gr3 including only a biconvex fourth lens L4, a negative meniscus fifth lens L5 having a convex surface facing the object side, and a positive meniscus lens having a convex surface facing the object side. And a fourth group Gr4 including the sixth lens L6. During zooming from the shortest focal length state to the longest focal length state, the first lens unit Gr1 moves while drawing a locus of a U-turn convex on the image side, and the second lens unit G1.
r2 and the third lens unit Gr3 monotonously move toward the object side while slightly widening the distance between each other,
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 fourth lens L4 alone 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 only a biconcave first lens L1,
A substantially plano-convex second lens L2 with the convex surface facing the object side, an aperture ST, and a paraxially biconcave third lens
A second group Gr2 composed of a lens L3 and a third group Gr composed solely of a biconvex fourth lens L4
And a fourth group Gr4 composed of only a negative meniscus fifth lens L5 with the convex surface facing the object side in a paraxial manner. During zooming from the shortest focal length state to the longest focal length state, the first group Gr1 moves to the image side, and the second group Gr2 and the third group Gr3 monotonously move to the object side while slightly changing the distance between each other. The fourth group Gr4 moves while drawing a locus of a U-turn convex to the object side. In focusing from an infinity in-focus condition to a finite object in-focus condition, the third lens unit fourth lens L4 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 having a convex surface facing the object side, and a biconvex third lens L3 and biconcave fourth
A first cemented lens DL1 formed by cementing the lens L4, a second lens unit Gr2 including a stop ST and a positive meniscus fifth lens L5 having a convex surface facing the object side, and a convex surface that is paraxially convex toward the object side. And a third unit Gr3 including only a positive meniscus sixth lens. During zooming from the shortest focal length state to the longest focal length state, the first group Gr1 moves to the image side, the second group Gr2 moves monotonously to the object side, and the third group Gr3 is fixed with respect to the image plane. ing. 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. 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 only a biconcave first lens L1, a biconvex second lens, a biconcave third lens L3, an aperture ST, and a biconvex lens. The second consisting of a shaped fourth lens L4
The lens unit includes a group Gr2 and a third group Gr3 including a negative meniscus fifth lens L5 having a convex surface facing the object side and a positive meniscus sixth lens L6 having a convex surface facing the object side. During zooming from the shortest focal length state to the longest focal length state, the first lens unit Gr1 moves while drawing a locus of a convex U-turn on the image side, and moves monotonically to the second lens unit Gr2 object side, while the third lens unit Gr3. Gr3 is fixed with respect to the image plane. In focusing from an infinity in-focus condition to a finite object in-focus condition, the fourth lens L4 alone is moved to the object side.

The zoom lens system according to each of the embodiments includes a second lens unit including a positive power lens element and a negative power lens element and having a positive power as a whole. In the negative lead type zoom lens system, the negative power of the second group contributes most to zooming. Therefore, the aberrations generated in the second lens unit, particularly the axial chromatic aberration, fluctuate greatly with zooming. In order to correct this, if at least the positive lens element and the negative lens element are included in the second group, it is impossible to balance axial chromatic aberration over the entire zoom range.

  Each zoom lens system satisfies the following conditional expressions.

Fnt ≤ 6.0 (1)
2.3 ≤ fw / ft ≤ 5.5 (2)
However,
Fnt: The minimum F-number of the zoom lens system at the longest focal length,
fw: focal length of the zoom lens system in the shortest focal length state,
ft: focal length of the zoom lens system in the longest focal length state,
It is.

Conditional expression (1) defines the minimum F-number in the longest focal length state of the zoom lens system. Minimum
If the f-number increases beyond 6.0, the image quality cannot be maintained enough to compete with silver halide film cameras. In particular, when the F-number exceeds 6.0, it becomes difficult to acquire moving images.

Conditional expression (2) defines the zoom ratio of the zoom lens system. Since the zoom lens system aimed at by the present invention is a small-sized zoom lens system having a central target of 3 to 4 times, this conditional expression (2) is defined. If the zoom ratio is smaller than the lower limit of the conditional expression (2), the significance of the optical zoom decreases, and the user benefit cannot be achieved. On the other hand, when the zoom ratio is larger than the upper limit of the conditional expression (2), the total length particularly in the longest focal length state becomes too large, and it is difficult to achieve the miniaturization of the zoom lens device. It is more desirable that the zoom ratio be a zoom lens system satisfying the following range.

3.1 ≤ fw / ft (2) '
Further, the zoom lens systems according to the embodiments satisfy the following conditional expression (3).

0.1 <T23w / fw <1.5 (3)
However,
T23w: axial top surface distance between the second group (most image side) and the group adjacent to the image side (most object side) in the shortest focal length state,
fw: focal length of the zoom lens system in the shortest focal length state,
It is.

Conditional expression (3) defines the axial distance between the second group of the zoom lens system and the group adjacent to the image side. If the lower limit of conditional expression (3) is exceeded, interference such as contact between the second and third lens elements in the shortest focal length state increases, and the lens barrel configuration becomes difficult and undesirable. . On the other hand, when the value exceeds the upper limit of the conditional expression (3), the total length in the optical axis direction in the shortest focal length state becomes long, and a compact zoom lens cannot be achieved. If the upper limit is exceeded, the distance between the first lens unit and the image plane increases due to the arrangement of power, so that the overall length in the optical axis direction increases, and the first lens unit is configured to ensure illuminance on the image plane. The lens diameter of the lens element becomes large, so that a compact zoom lens system cannot be achieved.

  Further, the zoom lens systems according to the embodiments satisfy the following conditional expression (4).

0.6 <Tsum / fw <1.8 (4)
However,
Tsum: Sum of the thicknesses of all the lens elements included in the zoom lens system,
fw: focal length of the zoom lens system in the shortest focal length state,
It is.

Conditional expression (4) defines the sum of the core thicknesses of all the lens elements included in the zoom lens system. The size in the optical axis direction of the zoom lens system when retracted is the largest factor that roughly determines the size in the thickness direction of a digital camera or a portable information device. The size in the optical axis direction at the time of collapsing cannot be physically smaller than the sum of the thicknesses of the lens elements. Therefore, if Tsum cannot be reduced, a compact zoom lens system cannot be achieved when retracted. Conditional expression (4) is exactly a conditional expression that defines the thickness when retracted. If the lower limit of the conditional expression is exceeded, it becomes difficult to physically configure the optical system. On the other hand, when the value exceeds the upper limit, the thickness of the lens becomes too large, which exceeds the limit allowed in digital cameras and portable information devices. It is to be noted that conditional expression (4) is more effective when it is set in the following range.

Tsum / fw <1.6 (4) '
Tsum / fw <1.5 (4) ''
It is preferable that the conditional expressions (3) and (4) be satisfied at the same time, so that the zoom lens system can be more effectively formed while achieving the respective effects.

It is desirable to have a first group which is arranged closest to the object side and is composed of 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. Also, if a lens element with a large lens diameter has a curvature,
Accordingly, the on-axis air gap between the lens elements also increases. 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.

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.

  Further, the zoom lens systems of the respective embodiments satisfy the following conditional expression (5).

ν1> 45 (5)
However,
ν1 is the Abbe number of one negative lens element constituting the first group.

Conditional expression (5) defines the Abbe number of the negative lens element forming the first unit. In a zoom lens system, a certain degree of aberration correction is usually performed for each group in order to minimize fluctuations in aberrations that occur during zooming. However, since the first group is constituted by a single negative lens element, it becomes extremely difficult to correct aberrations in the lens groups, particularly to correct axial chromatic aberration. Therefore, in the zoom lens according to the embodiment, it is necessary to balance the aberration by canceling the axial chromatic aberration generated in the first group by the other group. However, when the negative lens element of the first group is formed of a material having an Abbe number exceeding the lower limit of the conditional expression (5), it is preferable that the fluctuation of the axial chromatic aberration exceeds the allowable range that can be corrected by the other groups. Absent.

It is more preferable that the conditional expression (5) satisfies the ranges of the conditional expression (5) ′ and the conditional expression (5) ″.

ν1> 60 (5)
ν1> 80 (5) ''
Further, the negative lens element constituting the first group is desirably formed by using a material having an abnormally low dispersion so that further correction of chromatic aberration can be achieved. Further, since the negative lens element constituting the first group is desirably provided with an aspherical shape for the purpose of distortion correction or the like, it is preferable that the negative lens element be a resin lens element that satisfies the conditional expression (5) that facilitates formation of the aspherical surface. Is also good.

In the zoom lens systems according to the embodiments, the diaphragm is arranged on the object side or image side of the second group, and in the second group. If the stop is located on the image side of this position, the outer diameter of the first lens unit becomes too large, so that a compact zoom lens system cannot be achieved.

Further, the zoom lens system according to each of the embodiments moves the positive lens group or the single lens element, which is disposed at a position closer to the image side than the stop and not included in the group closest to the image side, on the optical axis. The focus is on. By making the focus group a positive lens group or a single lens element located on the image side of the stop and not included in the group closest to the image side, the weight is small and the movement amount during focusing is small. Since a small lens group or a single lens element can be focused, it is effective in reducing the load on the lens barrel configuration and the drive motor.

In addition, it is desirable that the group closest to the image side includes a positive lens element and a negative lens element, and has a configuration having a positive power as a whole. With such a configuration, there is an effect that a fluctuation due to zooming of the axial chromatic aberration generated by one negative lens element of the first group can be favorably corrected. In addition, it is also effective in correcting off-axis coma, particularly in the shortest focal length state. Further, by fixing the group closest to the image side with respect to the image plane, it is possible to more properly correct axial chromatic aberration caused by zooming, and to simplify the lens barrel configuration.

Each lens group constituting each of the embodiments described above includes only a refractive 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 9 listed below are the first to first examples described above.
Lens configuration diagrams respectively corresponding to the ninth embodiment and representing the first to ninth embodiments
(Figures 1 to 9 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 9, 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 = 6.0-11.4-17.3 mm
FNo. = 3.60-3.60-3.60
[Curvature radius] [Shaft upper surface interval] [Refractive index (Nd)] [Abbe number]
r1 * = -52.734
d1 = 1.200 N1 = 1.60046 ν1 = 58.26
r2 * = 5.737
d2 = 1.072
r3 = 7.771
d3 = 1.684 N2 = 1.84666 ν2 = 23.82
r4 = 10.891
d4 = 15.832-5.360-1.401
r5 = ∞
d5 = 0.600
r6 = 6.210
d6 = 4.583 N3 = 1.75314 ν3 = 51.62
r7 = -21.829
d7 = 0.800 N4 = 1.84666 ν4 = 23.82
r8 * = 12.477
d8 = 5.429
r9 = 11.255
d9 = 1.941 N5 = 1.68759 ν5 = 54.15
r10 = 74.056
d10 = 2.393-7.658-13.392
r11 * = 12.915
d11 = 0.905 N6 = 1.52510 ν6 = 56.38
r12 * = 15.606
d12 = 1.545
r13 = ∞
d13 = 2.000 N7 = 1.52510 ν7 = 56.38
r14 = ∞

[Aspheric coefficient]
r1
ε = 0.10000E + 01
A4 = -0.37415E-03
A6 = -0.18870E-05
A8 = 0.56110E-06
A10 = -0.24618E-07

r8
ε = 0.10000E + 01
A4 = 0.11120E-02
A6 = 0.43984E-04
A8 = -0.17238E-07
A10 = 0.18144E-06

r11
ε = 0.10000E + 01
A4 = -0.39690E-02
A6 = 0.72811E-03
A8 = -0.19568E-05
A10 = 0.96087E-07

r12
ε = 0.10000E + 01
A4 = -0.37358E-02
A6 = 0.996421E-05

<Example 2>
f = 5.6-12.9-16.1 mm
FNo. = 2.95-4.01-4.45
[Curvature radius] [Shaft upper surface interval] [Refractive index (Nd)] [Abbe number]
r1 * = -24.000
d1 = 1.200 N1 = 1.49310 ν1 = 83.58
r2 * = 8.123
d2 = 20.351-5.732-3.353
r3 = 6.991
d3 = 2.638 N2 = 1.72375 ν2 = 52.66
r4 = -34.740
d4 = 0.900
r5 = ∞
d5 = 1.000
r6 * = -9.988
d6 = 0.800 N3 = 1.84666 ν3 = 23.82
r7 * = 247.216
d7 = 6.049-6.611-6.879
r8 = 16.911
d8 = 1.806 N4 = 1.77436 ν4 = 48.39
r9 = -46.007
d9 = 0.800-9.345-13.337
r10 = 9.008
d10 = 0.800 N5 = 1.84666 ν5 = 23.82
r11 = 4.749
d11 = 0.301
r12 * = 5.048
d12 = 3.555 N6 = 1.52510 ν6 = 56.38
r13 * = 21.908
d13 = 0.800
r14 = ∞
d14 = 2.000 N7 = 1.51680 ν7 = 64.20
r15 = ∞

[Aspheric coefficient]
r1
ε = 0.10000E + 01
A4 = -0.63439E-04
A6 = 0.68501E-05
A8 = -0.66696E-07
A10 = -0.17038E-09

r2
ε = 0.10000E + 01
A4 = -0.47028E-03
A6 = 0.69477E-06
A8 = 0.66535E-06
A10 = -0.15800E-07

r6
ε = 0.10000E + 01
A4 = 0.59417E-03
A6 = 0.46685E-04
A8 = -0.77214E-05
A10 = 0.39203E-06

r7
ε = 0.10000E + 01
A4 = 0.12314E-02
A6 = 0.80651E-04
A8 = -0.10222E-04
A10 = 0.55470E-06

r12
ε = 0.10000E + 01
A4 = -0.59528E-03
A6 = -0.10325E-04
A8 = -0.14170E-06
A10 = -0.31345E-06

r13
ε = 0.10000E + 01
A4 = -0.55636E-03
A6 = 0.13842E-03
A8 = -0.20578E-04
A10 = 0.36116E-06

<Example 3>
f = 6.0-12.0-17.3 mm
FNo. = 2.95-3.60-3.84
[Curvature radius] [Shaft upper surface interval] [Refractive index (Nd)] [Abbe number]
r1 * = 72.689
d1 = 1.200 N1 = 1.49310 ν1 = 83.58
r2 * = 8.018
d2 = 28.005-8.738-1.125
r3 = 5.404
d3 = 2.577 N2 = 1.70206 ν2 = 53.53
r4 = -4231.909
d4 = 0.900
r5 = ∞
d5 = 1.271
r6 * = -10.108
d6 = 0.800 N3 = 1.84666 ν3 = 23.82
r7 * = 19.972
d7 = 4.900-5.414-4.248
r8 = 12.483
d8 = 2.589 N4 = 1.69005 ν4 = 54.04
r9 = -18.055
d9 = 0.800-2.578-8.087
r10 * = 7.794
d10 = 1.157 N5 = 1.80518 ν5 = 25.43
r11 * = 5.486
d11 = 0.800-2.807-1.046
r12 = ∞
d12 = 2.000 N6 = 1.51680 ν6 = 64.20
r13 = ∞

[Aspheric coefficient]
r1
ε = 0.10000E + 01
A4 = -0.15783E-03
A6 = 0.29784E-05
A8 = -0.83049E-07
A10 = 0.69898E-09

r2
ε = 0.10000E + 01
A4 = -0.37748E-03
A6 = 0.46708E-05
A8 = -0. 33213E-06
A10 = 0.30433E-08

r6
ε = 0.10000E + 01
A4 = -0.36757E-02
A6 = 0.36847E-03
A8 = -0.10565E-04
A10 = -0.20504E-05

r7
ε = 0.10000E + 01
A4 = -0.21103E-02
A6 = 0.46641E-03
A8 = -0.26240E-04

r10
ε = 0.10000E + 01
A4 = -0.57224E-02
A6 = -0.62282E-05
A8 = 0.46111E-05
A10 = -0.39249E-06

r11
ε = 0.10000E + 01
A4 = -0.81522E-02
A6 = 0.16684E-03
A8 = -0.53316E-05

<Example 4>
f = 7.5-9.9-21.6 mm
FNo. = 2.90-3.26-4.98
[Curvature radius] [Shaft upper surface interval] [Refractive index (Nd)] [Abbe number]
r1 * = -78.144
d1 = 1.500 N1 = 1.75354 ν1 = 51.60
r2 * = 8.785
d2 = 1.320
r3 = 12.547
d3 = 2.440 N2 = 1.84666 ν2 = 23.82
r4 = 24.990
d4 = 22.790-15.111-2.112
r5 = 8.616
d5 = 6.588 N3 = 1.75450 ν3 = 51.57
r6 = -24.529
d6 = 1.100 N4 = 1.84666 ν4 = 23.82
r7 * = 17.941
d7 = 1.000
r8 = ∞
d8 = 5.775
r9 = 14.333
d9 = 2.283 N5 = 1.64307 ν5 = 56.35
r10 = 141.468
d10 = 4.835-7.156-18.471
r11 * = 6.848
d11 = 1.058 N6 = 1.52510 ν6 = 56.38
r12 * = 7.139
d12 = 0.800
r13 = ∞
d13 = 2.500 N7 = 1.51680 ν6 = 64.20
r14 = ∞

[Aspheric coefficient]
r1
ε = 0.10000E + 01
A4 = 0.45575E-04
A6 = -0.27870E-06

r2
ε = 0.10000E + 01
A4 = -0.78792E-04
A6 = -0.22581E-05
A8 = 0.30224E-07
A10 = -0.68640E-09

r7
ε = 0.10000E + 01
A4 = 0.46811E-03
A6 = -0.25786E-05
A8 = 0.19297E-05
A10 = -0.11089E-06

r11
ε = 0.10000E + 01
A4 = -0.40664E-03
A6 = -0.15107E-03
A8 = 0.17297E-05
A10 = -0.56102E-07

r12
ε = 0.10000E + 01
A4 = 0.35021E-03
A6 = -0.22774E-03
A8 = 0.35741E-05
A10 = -0.18748E-07

<Example 5>
f = 5.6-16.1-21.2 mm
FNo. = 2.95-4.51-5.27
[Curvature radius] [Shaft upper surface interval] [Refractive index (Nd)] [Abbe number]
r1 * = -39.852
d1 = 1.200 N1 = 1.49310 ν1 = 83.58
r2 * = 7.943
d2 = 27.324-5.086-2.210
r3 = 9.089
d3 = 2.617 N2 = 1.75450 ν2 = 57.57
r4 = -26.827
d4 = 1.220
r5 * = -45.076
d5 = 0.800 N3 = 1.84666 ν3 = 23.82
r6 * = 18.718
d6 = 1.188
r7 = ∞
d7 = 8.466
r8 = 19.274
d8 = 1.710 N4 = 1.76213 ν4 = 50.28
r9 = -79.564
d9 = 1.000-13.487-19.631
r10 = 19.602
d10 = 0.800 N5 = 1.79850 ν5 = 22.60
r11 = 6.499
d11 = 0.100
r12 * = 5.624
d12 = 3.076 N6 = 1.52510 ν6 = 56.38
r13 * = 67.250
d13 = 1.000
r14 = ∞
d14 = 2.000 N7 = 1.51680 ν7 = 64.20
r15 = ∞

[Aspheric coefficient]
r1
ε = 0.10000E + 01
A4 = -0.64385E-03
A6 = 0.20445E-04
A8 = -0.22702E-06
A10 = 0.79381E-09

r2
ε = 0.10000E + 01
A4 = -0.10137E-02
A6 = 0.90231E-05
A8 = 0.49260E-06
A10 = -0.10596E-07

r5
ε = 0.10000E + 01
A4 = -0.61443E-03
A6 = 0.40451E-04
A8 = -0.38476E-05
A10 = 0.18991E-06

r6
ε = 0.10000E + 01
A4 = -0.28745E-03
A6 = 0.58066E-04
A8 = -0.54298E-05
A10 = 0.27306E-06

r12
ε = 0.10000E + 01
A4 = 0.65072E-03
A6 = -0.30424E-03
A8 = 0.28044E-04
A10 = -0.12221E-05

r13
ε = 0.10000E + 01
A4 = 0.27656E-02
A6 = -0.45141E-03
A8 = 0.33907E-04
A10 = -0.12549E-05

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 (6)

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:
A first group having a negative power disposed closest to the object side, a lens element having a positive power, a second group having a positive power as a whole including a lens element having a negative power, comprising a plurality of groups including
A zoom lens apparatus characterized in that all lens surfaces constituting the zoom lens system are refracting surfaces, and zooming is performed by changing the distance between the groups, and the following conditional expressions are satisfied;
2.3 ≤ ft / fw ≤ 5.5
0.1 <T23w / fw <1.5
0.6 <Tsum / fw <1.8
However,
fw: focal length of the zoom lens system in the shortest focal length state,
ft: focal length of the zoom lens system in the longest focal length state,
T23w: axial top surface distance between the second group and the group adjacent to the image side in the shortest focal length state,
Tsum: Sum of the thicknesses of all the lens elements included in the zoom lens system,
It is. The zoom lens apparatus according to claim 1, wherein the first group of the zoom lens system moves during zooming. The zoom lens system includes, in order from the object side, a first group, a second group having a positive power as a whole provided adjacent to the first group, and an overall group provided adjacent to the second group. The zoom lens apparatus according to claim 1, comprising a plurality of groups including a third group having a positive power. The zoom lens apparatus according to claim 1, wherein the optically power group disposed closest to the image side of the zoom lens system includes two or more lens elements.   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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