JP5776441B2 - Zoom lens and information device - Google Patents

Description

The present invention relates to a zoom lens and an information device.
The zoom lens of the present invention can be implemented as a zoom lens for imaging in an imaging apparatus such as a silver halide photographic camera, a digital still camera, a video camera, and a digital video camera. The information device can be implemented as a digital still camera, a portable information terminal device, or the like.

In recent years, a zoom lens is generally used as a photographing optical system used for a digital still camera or the like. In particular, a “zoom lens including an angle of view of about 50 mm in terms of a 35 mm format in the focal length range” is generally known.
In these zoom lenses, there are strong user demands for downsizing, wide angle, and high speed auto-focus (hereinafter referred to as AF).

  In order from the object side to the image side, a so-called positive lead type zoom lens having a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a succeeding group following the first lens group has a variable magnification. It is easy to increase the ratio, and it is easy to reduce the overall length by the configuration of the front of the positive group, and various types are conventionally known (Patent Documents 1 to 5).

  The zoom lenses described in Patent Documents 1 to 5 are all of the so-called “inner focus type”, and the one described in Patent Document 1 performs focusing by moving the second lens group. In all of the described ones, focusing is performed by moving the third lens group.

In the case of the “zoom lens that performs focusing by moving the second lens group” described in Patent Document 1, since the weight of the second lens group to be moved is large during focusing, the motor and the actuator tend to be large, and the maximum diameter of the lens barrel Tends to grow.
Since the weight of the second lens group is large, there is no problem in terms of speeding up AF and “quieting during moving image shooting”.

  In the zoom lenses described in Patent Documents 2 to 5, focusing is performed by a third lens group having a negative refractive power.

However, in the zoom lenses described in Patent Documents 2 to 4, it is difficult to say that the focus group is sufficiently light.
In the zoom lens described in Patent Document 5, the third lens group that performs focusing is composed of “one negative lens”, the focus group is reduced in weight, the AF speed is increased, the lens barrel diameter is reduced, and the like. Can be planned. However, there is still room for improvement in the performance of the third lens group in terms of performance and zoom lens compactness.

  In view of the above, the present invention is an inner focus system that has a small amount of movement of the focus group, is small and high performance, has a half angle of view of 36.8 degrees or more at the wide angle end, and a zoom ratio of 2.8 times. It is an object of the present invention to make it possible to realize a zoom lens having a resolving power corresponding to an imaging element of about 5 times to 5 million to 10 million pixels.

  The present invention is also the above-described inner focus method, in which the amount of movement of the focus group is small, small size and high performance, the half angle of view at the wide angle end is 36.8 degrees or more, and the zoom ratio is about 2.8 to 5 times. It is an object of the present invention to realize a zoom lens having a resolving power corresponding to an image pickup element exceeding 5 to 10 million pixels.

  It is another object of the present invention to provide a compact, lightweight information device with a good performance equipped with such a zoom lens.

  The zoom lens according to claim 1 includes, in order from the object side along the optical axis, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a negative refractive power, A fourth lens group having a refracting power and a fifth lens group having a positive refracting power, and an aperture stop disposed between the third lens group and the fourth lens group, from the wide-angle end to the telephoto end. During zooming, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group increases, and the distance between the third lens group and the fourth lens group decreases. A zoom lens in which the distance between the fourth lens group and the fifth lens group is reduced, and is characterized by the following points.

  That is, the third lens group is composed of one negative lens, and this negative lens is a negative meniscus lens having a concave surface directed toward the object side, and focusing is performed by movement of the third lens group in the optical axis direction.

Radius of curvature of object side surface of third lens group: R31, Radius of curvature of image side surface of third lens group: R32, Focal length of third lens group: F3, Composite focal length of second and third lens groups at telephoto end : F23w, the combined focal length of the second and third lens groups at the telephoto end: F23t, the focal length at the wide-angle end: Fw, the focal length at the telephoto end: Ft, √ (Fw × Ft): Fm is a condition:
(1) 1.0 <(R31-R32) / | F23w | <10.0
(2) 1.0 <(R31-R32) / | F23t | <10.0
(3) 1.4 <| F3 | / Fm <2.5
Satisfied.

In the zoom lens according to claim 1, the maximum image height is Y ′, and the focal length at the wide angle end is Fw.
(5) 0.75 <Y ′ / Fw
Is preferably satisfied (claim 2).

Claims 1 and 2 The zoom lens according the focal length at the telephoto end: Ft, the focal length at the wide angle end: Fw is the condition:
(6) 2.8 <Ft / Fw
Satisfied.

The zoom lens according to claim 1 or 2, wherein the Abbe number νd of the material of one negative lens constituting the third lens group is:
(4) νd> 50
Is preferably satisfied ( Claim 3 ). Of course, it is also possible to use a material outside the range of the condition (4) as the material of the single lens.

The information apparatus of this invention has the zoom lens according to any one of claims 1 to 3 as a “photographing optical system” ( claim 4 ). Examples of such an information device include a silver salt camera and a video camera.

The information device according to claim 4 can be “an information device having a photographing function in which an object image by a zoom lens is formed on a light receiving surface of an image sensor” ( claim 5 ), and a digital still camera, It can be implemented as a digital video camera.

The information device according to claim 5 can also be configured as a “portable information terminal device” ( claim 6 ).

Supplement the explanation.
As described above, the zoom lens according to the present invention is an inner focus type in which focusing is performed by moving the third lens group. The “third lens group” as the focus group is composed of one negative lens, and the condition (1 ) To (3) and (6) .

Since there is only one focus group, it is lightweight, and it is possible to achieve “silence” during focusing, such as speeding up AF and reducing the diameter of the lens barrel.
However, since it is a “lens group that moves frequently” by the focusing operation, it is necessary to satisfactorily suppress the eccentricity error sensitivity. Decreasing the “power of the third lens group” in order to suppress the decentration error sensitivity is disadvantageous for downsizing.

Conditions (1) and (2) are conditions for determining “an appropriate range of power balance of each surface” of one negative lens constituting the third lens group.
If the range of the conditions (1) and (2) is exceeded, the burden on each surface increases, and not only the occurrence of various aberrations but also the decentration error sensitivity increases.
The numerator of the parameters of the conditions (1) and (2) is “(R31−R32)” is “positive value”. From this, one negative lens constituting the third lens group has “concave surface on the object side”. Negative meniscus lens ".

Condition (3) is a condition for determining an appropriate range of the focal length F3 of the third lens group.
Fm in the denominator of the parameter is “√ (Fw × Ft)”, which gives the “geometric mean” of the focal lengths at the wide-angle end and the telephoto end.

When the parameter: | F3 | / Fm decreases, the focal length of the third lens group decreases, and the negative power of the third lens group increases, which is advantageous for downsizing. However, if the lower limit of the condition (3) is exceeded, the decentration error sensitivity of the third lens group becomes large, which is disadvantageous in terms of workability.
If the upper limit of condition (3) is exceeded, the negative power of the third lens group becomes small, which is advantageous in terms of workability, but disadvantageous for miniaturization.

  Only by satisfying the conditions (1), (2), and (3) at the same time can a single lens be used for a focus group that is suitable for miniaturization, has low decentration error sensitivity, and is free from various aberrations. It becomes possible.

More preferably, the parameters of the above conditions (1) to (3) are as follows:
(1A) 1.5 <(R31-R32) / | F23w | <9.5
(2A) 1.5 <(R31-R32) / | F23t | <9.5
(3A) 1.5 <| F3 | / Fm <2.3
Is preferably satisfied.

  The zoom lens according to the present invention has a “five-group configuration” as described above, and the first to third lens groups located on the object side of the aperture stop are the “front group”, and the fourth and fifth lens groups are the “successive group”. Then, since the subsequent group is composed of two lens groups, the “burden on zooming” of the front group is reduced, and the degree of freedom in design is increased, which is advantageous in terms of aberration correction and workability.

  In zooming, all lens groups move and contribute to zooming, so the burden of zooming on each lens group is dispersed and reduced, which is advantageous in terms of aberration correction and workability. This makes it possible to efficiently reduce the “movement amount during zooming” of the first lens group, which is advantageous for downsizing.

  The condition (5) of claim 2 is a condition for regulating the angle of view, and a half angle of view at the wide angle end can be 36.8 degrees or more.

The parameter of the condition (5) is more preferably the condition:
(5A) 0.87 <Y ′ / Fw
Is preferably satisfied.

The condition (6) of claim 1 regulates the zoom ratio and can realize a zoom ratio of 2.8 times or more.

The zoom ratio is more preferably the following conditions:
(6A) 2.8 <Ft / Fw <5
Good to be satisfied.

  By configuring the third lens group with a material that satisfies the condition (4) of claim 4, further improvement in performance can be achieved.

  That is, since the third lens group is composed of a single lens, the use of “relatively low dispersion glass” for this lens can suppress the occurrence of various chromatic aberrations and reduce the burden on other groups. Thus, aberration correction can be performed more effectively.

Although it may be simple in terms of mechanism that the aperture diameter of the aperture stop is “constant regardless of zooming”, the change in F number is reduced by making the aperture diameter at the telephoto end larger than at the wide-angle end. You can also
If it is necessary to reduce the amount of light that reaches the image plane, the aperture may be made smaller. However, reducing the amount of light by inserting an ND filter or the like without greatly changing the aperture diameter lowers the resolving power due to the diffraction phenomenon. Is preferable.

  As described above, according to the zoom lens of the present invention, the focusing group for focusing is sufficiently compact, the amount of movement during focusing is small, the size can be reduced, and high-speed AF is possible.

  And, as in the embodiments described later, the half angle of view at the wide-angle end is 36.8 degrees or more, the zoom ratio is about 2.8 to 5 times, and the aberration is sufficiently corrected, and the imaging is small and has high resolution. This can be realized as a zoom lens having a resolution corresponding to the element.

  By mounting such a zoom lens, it is possible to realize a small and high-performance imaging device.

FIG. 3 is a diagram for explaining a zoom lens of Example 1; FIG. 3 is an aberration diagram at a wide angle end of the zoom lens according to Example 1; FIG. 4 is an aberration diagram for the zoom lens of Example 1 at an intermediate focal length. FIG. 4 is an aberration diagram at a telephoto end of the zoom lens in Example 1; 6 is a diagram for explaining a zoom lens according to Example 2. FIG. FIG. 6 is an aberration diagram at a wide-angle end of the zoom lens according to Example 2; 6 is an aberration diagram at an intermediate focal length of the zoom lens of Example 2. FIG. 6 is an aberration diagram at a telephoto end of a zoom lens in Example 2. FIG. 6 is a diagram for explaining a zoom lens according to Example 3. FIG. FIG. 10 is an aberration diagram at a wide-angle end of the zoom lens according to Example 3; FIG. 10 is an aberration diagram at an intermediate focal length of the zoom lens according to Example 3; 6 is an aberration diagram at a telephoto end of a zoom lens in Example 3; FIG. FIG. 10 is a diagram for explaining a zoom lens according to Example 4; FIG. 10 is an aberration diagram at a wide-angle end of the zoom lens according to Example 4; FIG. 10 is an aberration diagram at an intermediate focal length of the zoom lens according to Example 4; FIG. 10 is an aberration diagram at a telephoto end of a zoom lens in Example 4; FIG. 10 is a diagram for explaining a zoom lens according to Example 5; FIG. 10 is an aberration diagram at a wide-angle end of the zoom lens according to Example 5; FIG. 10 is an aberration diagram at an intermediate focal length of the zoom lens according to Example 5; 10 is an aberration diagram at a telephoto end of a zoom lens in Example 5. FIG. FIG. 10 is a diagram for explaining a zoom lens according to Example 6; FIG. 10 is an aberration diagram at a wide-angle end of the zoom lens according to Example 6; FIG. 10 is an aberration diagram at an intermediate focal length of the zoom lens according to Example 6; 10 is an aberration diagram at a telephoto end of a zoom lens in Example 6; FIG. FIG. 10 is a diagram for explaining a zoom lens according to Example 7; 10 is an aberration diagram at a wide-angle end of a zoom lens according to Example 7. FIG. 10 is an aberration diagram at an intermediate focal length of the zoom lens in Example 7. FIG. 10 is an aberration diagram at a telephoto end of a zoom lens in Example 7. FIG. FIG. 10 is a diagram for explaining a zoom lens according to Example 8; 10 is an aberration diagram at a wide-angle end of the zoom lens according to Example 8; FIG. FIG. 10 is an aberration diagram at an intermediate focal length of the zoom lens according to Example 8; 10 is an aberration diagram at a telephoto end of a zoom lens in Example 8. FIG. It is a figure for demonstrating one Embodiment of a portable information terminal device. It is a figure for demonstrating the system configuration | structure of the apparatus of FIG.

  Hereinafter, embodiments will be described.

  FIG. 1, FIG. 5, FIG. 9, FIG. 13, FIG. 17, FIG. 21, FIG. These embodiments correspond to Examples 1 to 8 described later in the above order.

  In order to avoid complications, the same reference numerals are used in the above drawings.

  That is, in FIGS. 1, 5, 9, 13, 13, 17, 21, 25, and 29, the left side is the object side and the right side is the image plane side.

  The zoom lens includes, in order from the object side along the optical axis, a first lens group I having a positive refractive power, a second lens group II having a negative refractive power, a third lens group III having a negative refractive power, and a positive refraction. A fourth lens group IV having a positive power and a fifth lens group V having a positive refractive power are disposed, and an aperture stop S is disposed between the third lens group III and the fourth lens group IV.

  In each figure, the upper diagram shows the lens arrangement at the wide angle end, the middle diagram shows the lens arrangement at the intermediate focal length, and the lower diagram shows the lens arrangement at the telephoto end. The “arrow” indicates the movement of each lens group accompanying zooming from the wide-angle end to the telephoto end.

As is clear from the above figures, in the zoom lens of the present invention, all the lens groups move during zooming from the wide-angle end to the telephoto end.
That is, the distance between the first lens group I and the second lens group II is increased, the distance between the second lens group II and the third lens group III is increased, and the third lens group III and the fourth lens group IV are increased. The interval decreases, and the interval between the fourth lens group IV and the fifth lens group V decreases. Further, at the time of zooming, the aperture stop S moves integrally with the fourth group.

  The third lens group III includes “one negative lens”, and this negative lens is a “negative meniscus lens having a concave surface facing the object side”. Then, focusing is performed by the movement of the third lens group III in the optical axis direction.

  In each of the above drawings, the symbol F drawn on the right side of the drawing is two transparent parallel plates.

  In a “camera apparatus using a solid-state image pickup device such as a CCD or CMOS” such as a digital still camera, a low-pass filter, an infrared cut glass, etc. are provided close to the light receiving surface of the solid-state image pickup device. The light receiving surface of the element is protected by a “cover glass”.

  The above-mentioned “transparent parallel plate” is obtained by virtually replacing various filters such as a low-pass filter and a cover glass with “two transparent parallel plates optically equivalent to these”.

In the zoom lens according to the embodiment shown in FIG. 1, the configuration of each lens group is as follows.
The first lens group I includes, in order from the object side, a cemented lens of a negative meniscus lens having a convex surface facing the object side and a positive meniscus lens having a convex surface facing the object side.

The second lens group II includes, in order from the object side, a negative meniscus lens having a convex surface directed toward the object side, a biconcave lens having both aspheric surfaces, and a biconvex lens.
The third lens group III includes one negative meniscus lens having a strong concave surface facing the object side.

  The fourth lens group IV includes, in order from the object side, a biconvex lens that is a double-sided aspheric surface having a stronger convex surface on the object side, and a cemented lens of the biconvex lens and the biconcave lens.

  The fifth lens unit V includes, in order from the object side, a biconvex lens that is a double-sided aspheric surface and a negative meniscus lens having a convex surface facing the object side.

In the zoom lens according to the embodiment shown in FIG. 5, the configuration of each lens group is as follows.
The first lens unit I includes, in order from the object side, a negative meniscus lens having a convex surface facing the object side and a cemented lens of a positive meniscus lens having a convex surface facing the object side.

  The second lens group II includes, in order from the object side, a negative meniscus lens having a convex surface directed toward the object side, a biconcave lens having both aspheric surfaces, and a biconvex lens.

  The third lens group III includes one negative meniscus lens having a strong concave surface facing the object side.

  The fourth lens group IV includes, in order from the object side, a biconvex lens that is a double-sided aspheric surface having a stronger convex surface on the object side, and a cemented lens of the biconvex lens and the biconcave lens.

  The fifth lens group V includes a biconvex lens having a double-sided aspheric surface and a negative meniscus lens having a convex surface directed toward the object side.

In the zoom lens shown in FIG. 9, the configuration of each lens group is as follows.
The first lens unit I includes, in order from the object side, a negative meniscus lens having a convex surface facing the object side and a cemented lens of a positive meniscus lens having a convex surface facing the object side.

  The second lens group II includes, in order from the object side, a negative meniscus lens having a convex surface directed toward the object side, a biconcave lens having both aspheric surfaces, and a biconvex lens.

  The third lens group III includes one negative meniscus lens having a strong concave surface facing the object side.

  The fourth lens group IV includes, in order from the object side, a biconvex lens that is a double-sided aspheric surface having a stronger convex surface on the object side, and a cemented lens of the biconvex lens and the biconcave lens.

  The fifth lens unit V includes, in order from the object side, a biconvex lens that is a double-sided aspheric surface and a negative meniscus lens having a convex surface facing the object side.

  In the zoom lens according to the embodiment shown in FIG. 13, the configuration of each lens group is as follows.

  The first lens unit I includes a negative meniscus lens having a convex surface directed toward the object side and a cemented lens of a positive meniscus lens having a convex surface directed toward the object side.

  The second lens group II includes, in order from the object side, a negative meniscus lens having a convex surface directed toward the object side, a biconcave lens having both aspheric surfaces, and a biconvex lens.

  The third lens group III includes one negative meniscus lens having a strong concave surface facing the object side.

  The fourth lens group IV includes, in order from the object side, a biconvex lens that is a double-sided aspheric surface having a stronger convex surface on the object side, and a cemented lens of the biconvex lens and the biconcave lens.

  The fifth lens unit V includes, in order from the object side, a biconvex lens that is a double-sided aspheric surface and a negative meniscus lens having a convex surface facing the object side.

  In the zoom lens according to the embodiment shown in FIG. 17, the configuration of each lens group is as follows.

  The first lens unit I includes, in order from the object side, a negative meniscus lens having a convex surface facing the object side and a cemented lens of a positive meniscus lens having a convex surface facing the object side.

  The second lens group II includes, in order from the object side, a negative meniscus lens having a convex surface directed toward the object side, a biconcave lens having both aspheric surfaces, and a biconvex lens.

  The third lens group III includes one negative meniscus lens having a strong concave surface facing the object side.

  The fourth lens group IV includes, in order from the object side, a biconvex lens that is a double-sided aspheric surface having a stronger convex surface on the object side, and a cemented lens of the biconvex lens and the biconcave lens.

  The fifth lens unit V includes, in order from the object side, a biconvex lens that is a double-sided aspheric surface and a negative meniscus lens having a convex surface facing the object side.

  In the zoom lens according to the embodiment shown in FIG. 21, the configuration of each lens group is as follows.

  The first lens unit I includes, in order from the object side, a negative meniscus lens having a convex surface facing the object side and a cemented lens of a positive meniscus lens having a convex surface facing the object side.

  The second lens group II includes, in order from the object side, a negative meniscus lens having a convex surface directed toward the object side, a biconcave lens having both aspheric surfaces, and a biconvex lens.

  The third lens group III includes one negative meniscus lens having a strong concave surface facing the object side.

  The fourth lens group IV includes, in order from the object side, a biconvex lens that is a double-sided aspheric surface having a stronger convex surface on the object side, and a cemented lens of the biconvex lens and the biconcave lens.

  The fifth lens unit V includes, in order from the object side, a biconvex lens that is a double-sided aspheric surface and a negative meniscus lens having a convex surface facing the object side.

  In the zoom lens according to the embodiment shown in FIG. 25, the configuration of each lens group is as follows.

  The first lens unit I includes, in order from the object side, a negative meniscus lens having a convex surface facing the object side and a cemented lens of a positive meniscus lens having a convex surface facing the object side.

  The second lens group II includes, in order from the object side, a negative meniscus lens having a convex surface directed toward the object side, a biconcave lens having both aspheric surfaces, and a biconvex lens.

  The third lens group III includes one negative meniscus lens having a strong concave surface facing the object side.

  The fourth lens group IV includes, in order from the object side, a biconvex lens that is a double-sided aspheric surface having a stronger convex surface on the object side, and a cemented lens of the biconvex lens and the biconcave lens.

  The fifth lens unit V includes, in order from the object side, a biconvex lens that is a double-sided aspheric surface and a negative meniscus lens having a convex surface facing the object side.

  In the zoom lens shown in FIG. 29, the configuration of each lens group is as follows.

  The first lens unit I includes, in order from the object side, a negative meniscus lens having a convex surface facing the object side and a cemented lens of a positive meniscus lens having a convex surface facing the object side.

  The second lens group II includes, in order from the object side, a negative meniscus lens having a convex surface directed toward the object side, a biconcave lens having both aspheric surfaces, and a biconvex lens.

  The third lens group III includes one negative meniscus lens having a strong concave surface facing the object side.

  The fourth lens group IV includes, in order from the object side, a biconvex lens that is a double-sided aspheric surface having a stronger convex surface on the object side, and a cemented lens of the biconvex lens and the biconcave lens.

  The fifth lens unit V includes, in order from the object side, a biconvex lens that is a double-sided aspherical surface with a stronger convex surface on the image side, and a negative meniscus lens with a convex surface on the object side.

One embodiment of a portable information terminal device will be described with reference to FIGS.
FIG. 32 shows the appearance of the camera device (camera function unit of the portable information terminal device), and FIG. 34 shows the system configuration of the portable information terminal device.
As shown in FIG. 34, the portable information terminal device 30 includes a photographing lens 31 and a light receiving element (a solid-state imaging device in which 5 to 10 million pixels are two-dimensionally arranged) 45, and is formed by the photographing lens 31. The “photographing object image” is read by the light receiving element 45. A finder 33 is also provided.

  As the photographic lens 31, the “imaging lens” according to any one of claims 1 to 4, more specifically, the imaging lens of Examples 1 to 8 described later is used.

  The output from the light receiving element 45 is processed by the signal processing device 42 under the control of the central processing unit 40, converted into digital information, and the digitized image information is received by the image processing device 41 under the control of the central processing unit 40. After being subjected to predetermined image processing, it is recorded in the semiconductor memory 44.

  The liquid crystal monitor 38 can display an image being image-processed by the image processing device 41 or can display an image recorded in the semiconductor memory 44. The image recorded in the semiconductor memory 44 can be transmitted to the outside using a communication card 43 or the like.

  The image processing apparatus 41 also has a function of performing “electrical shading correction”, “trimming of the image center”, and the like.

  As shown in FIG. 33, when the photographic lens 31 is carried, it is in a retracted state as shown in FIG. 33 (a). When the user operates the power switch 36 to turn on the power, the mirror 31 as shown in FIG. The torso is paid out.

  At this time, each group of zoom lenses in the lens barrel is “arranged at an infinite object distance”, and “focusing to a finite object distance” is performed by half-pressing the shutter button 35. Zooming is performed by operating the zooming adjustment unit 34, and the finder 33 performs scaling in conjunction with the zooming operation.

  The focusing operation is performed by “moving the third group” as described above.

  When an image recorded in the semiconductor memory 44 is displayed on the liquid crystal monitor 38 or transmitted to the outside using a communication card or the like, the operation button 37 shown in FIG. 33C is used. A semiconductor memory, a communication card, and the like are used by being inserted into dedicated or general-purpose slots 39A and 39B, respectively.

  When the photographing lens 31 is in the retracted state, the lens groups do not necessarily have to be aligned on the optical axis. For example, the first lens group and the second lens group are retracted from the optical axis, If the mechanism is “stored in parallel with the lens group”, the portable information terminal device can be further reduced in thickness.

  In the “portable information terminal apparatus having a camera device as a photographing unit” as described above, the imaging lens of Examples 1 to 8 can be used as the photographing lens 31, and 5 million to 10 million pixels can be used. A portable information terminal device having a high image quality and a small camera function using the light receiving element 45 exceeding can be realized.

  Hereinafter, eight specific examples will be given.

The meanings of the symbols in the examples are as follows.
f: Focal length of entire system F: F number ω: Half angle of view (deg)
Surface number: Surface number: Number of surface (lens surface, diaphragm surface, filter, light receiving surface) counted from the object side R: Radius of curvature (Paraxial radius of curvature for aspheric surfaces)
D: Surface spacing Nd: Refractive index νd: Abbe number K: Aspherical conical constant A4: Fourth-order aspherical constant A6: Sixth-order aspherical constant A8: Eighth-order aspherical constant A10: Tenth-order aspherical surface Constant A12: 12th-order aspherical constant A14: 14th-order aspherical constant

The aspherical shape is a reciprocal of the paraxial radius of curvature (paraxial curvature): C, height from the optical axis: H, conic constant: K, and the non-spherical coefficients of the above orders, where X is the non-axis in the optical axis direction. As a spherical quantity, the well-known formula X = CH ² / [1 + √ {1− (1 + K) C ² H ² }]
+ A4 · H ⁴ + A6 · H ⁶ + A8 · H ⁸ + A10 · H ¹⁰ + A12 · H ¹² + A14 · H ¹⁴
The shape is specified by giving a paraxial radius of curvature, a conic constant, and an aspherical coefficient.

"Example 1"
Example 1 is the zoom lens shown in FIG.
f = 16.146-53.852 F = 3.59-5.93 ω = 42.8-14.5
Surface number R D Nd νd
1 35.22784 1.30000 1.84666 23.7800
2 25.43981 5.58108 1.69680 55.5300
3 161.95730 Variable A
4 66.68463 0.97007 2.00100 29.1300
5 10.93000 6.31830
6 -29.18377 0.80000 1.69350 53.1800
7 26.19043 0.09955
8 25.80601 4.24896 1.84666 23.7800
9 -27.63060 Variable B
10 -20.24167 0.80000 1.60300 65.4400 (S-PHM53)
11 -50.23484 Variable C
12 ∞ (Aperture) 1.45001
13 15.31467 3.43574 1.51633 64.0600
14 -38.17926 0.10000
15 21.44923 3.93180 1.53172 48.8400
16 -17.87906 1.45000 1.83400 37.1600
17 19.58694 Variable D
18 19.29863 4.94809 1.58913 61.1500
19 -19.58674 0.23493
20 48.01352 0.80173 1.90366 31.3200
21 16.49362 Variable E
22 ∞ 0.70000 1.53770 66.6000
23 ∞ 1.50000
24 ∞ 0.70000 1.50000 64.0000
25 ∞.

"Aspherical data"
Aspherical data are shown below.

6th page
K = 0
A4 = -1.12571E-05
A6 = 1.21899E-07
A8 = 2.76874E-09
A10 = -4.5160E-11
A12 = 1.38009E-13
7th page
K = 0
A4 = -4.98762E-05
A6 = 3.02710E-07
A8 = -1.83352E-09
A10 = -4.9553E-12
Side 13
K = 0
A4 = -2.23034E-05
A6 = -3.30061E-08
A8 = 1.96596E-09
A10 = -4.33079E-11
14th page
K = 0
A4 = -6.86789E-06
A6 = 1.59127E-07
A8 = -8.05125E-10
A10 = -2.46291E-11
18th page
K = -4.76959
A4 = -2.06414E-06
A6 = -1.71695E-07
A8 = -2.33143E-09
A10 = 6.08643E-12
19th page
K = 0.25043
A4 = 3.72591E-05
A6 = -4.11291E-08
A8 = -2.02648E-09
A10 = 3.86766E-12
In the notation of the aspherical data described above, “E−n” represents “power of 10 (10 ⁻ⁿ )” (the same applies to the following examples).

The glass material of the lens of the third lens group is assumed to be “S-PHM53” manufactured by OHARA.
Νd and θg, F of S-PHM53 are as follows from the published catalog.
νd = 65.44
θg, F = 0.5401
"Variable amount"
Variable amounts of data are shown in Table 1.

  FIG. 2, FIG. 3, and FIG. 4 sequentially show aberration diagrams of the first embodiment at the wide-angle end, the intermediate focal length, and the telephoto end. The broken line in the spherical aberration diagram represents the sine condition, the solid line in the astigmatism diagram represents the sagittal, and the broken line represents the meridional. Further, “g” and “d” represent the g line and the d line, respectively. The same applies to the other aberration diagrams below.

"Example 2"
Example 2 is the zoom lens shown in FIG.
f = 16.146-53.851 F = 3.6-5.77 ω = 42.87-14.47
Surface number R D Nd νd
1 43.11718 1.29999 1.84666 23.78
2 31.73933 5.57706 1.69680 55.53
3 190.09719 Variable A
4 55.24695 0.97008 2.00100 29.13
5 10.53158 7.00758
6 -37.69153 0.80000 1.69350 53.18
7 39.79764 0.12000
8 35.75261 4.22772 1.84666 23.78
9 -27.02142 Variable B
10 -22.16816 0.80000 1.60300 65.44 (S-PHM53)
11 -68.86241 Variable C
12 ∞ (Aperture) 1.45020
13 17.70983 4.99510 1.51633 64.06
14 -25.76032 0.10000
15 24.82196 3.73181 1.53172 48.84
16 -18.83887 1.44999 1.83400 37.16
17 19.93203 Variable D
18 18.95445 5.30000 1.58913 61.15
19 -22.79198 0.10000
20 46.10650 0.80000 1.90366 31.32
21 16.80062 Variable E
22 ∞ 0.70000 1.53770 66.60
23 ∞ 1.50000
24 ∞ 0.70000 1.50000 64.00
25 ∞.

"Aspheric data"
Aspherical data are shown below.

6th page
K = 0
A4 = -6.13912E-05
A6 = 6.02764E-07
A8 = -3.68927E-09
A10 = -5.86282E-12
7th page
K = 0
A4 = -9.55771E-05
A6 = 6.67024E-07
A8 = -5.78157E-09
A10 = 3.44512E-12
Side 13
K = 0
A4 = -2.21195E-05
A6 = -1.07672E-06
A8 = 1.98544E-08
A10 = -3.47093E-10
14th page
K = 0
A4 = 5.12674E-06
A6 = -9.94310E-07
A8 = 1.53589E-08
A10 = -2.78900E-10
18th page
K = -1.2879
A4 = -1.57778E-05
A6 = -7.80973E-08
A8 = -8.69905E-10
A10 = 3.89552E-12
19th page
K = 0.98584
A4 = 4.43195E-05
A6 = 5.66872E-08
A8 = -2.64609E-09
A10 = 1.33387E-11.

The glass material of the lens of the third lens group is assumed to be S-PHM53 manufactured by OHARA.
Νd and θg, F of S-PHM53 are as follows from the published catalog.
νd = 65.44
θg, F = 0.5401
"Variable amount"
Variable amounts of data are shown in Table 2.

  FIG. 6, FIG. 7, and FIG. 8 show aberration diagrams of Example 2 at the wide-angle end, the intermediate focal length, and the telephoto end, respectively.

"Example 3"
Example 3 is the zoom lens shown in FIG.
f = 16.146 to 53.85 F = 3.62 to 5.67 ω = 42.8 to 14.46
Surface number R D Nd νd
1 44.83622 1.30000 1.84666 23.78
2 30.32788 5.80250 1.77250 49.60
3 152.20233 Variable A
4 55.56877 0.97009 2.00100 29.13
5 10.85110 6.67902
6 -40.92454 0.80000
7 36.32245 0.65885
8 30.89732 4.44422 1.84666 23.78
9 -26.99833 Variable B
10 -24.45877 0.80000 1.64850 53.02 (S-BSM71)
11 -103.58339 Variable C
12 ∞ (Aperture) 1.45008
13 16.52481 5.35383 1.51633 64.06
14 -25.99633 0.10000
15 23.78029 3.61747 1.51742 52.43
16 -22.01894 1.45000 1.83400 37.16
17 17.55937 Variable D
18 19.88520 5.30000 1.58913 61.15
19 -22.74438 0.10000
20 53.58387 0.80000 1.90366 31.32
21 18.67841 Variable E
22 ∞ 0.70000 1.53770 66.60
23 ∞ 1.50000
24 ∞ 0.70000 1.50000 64.00
25 ∞.

"Aspheric data"
The aspheric data is shown below.

6th page
K = 0
A4 = -8.18151E-06
A6 = -2.01833E-07
A8 = 2.53333E-09
A10 = -1.29107E-11
7th page
K = 0
A4 = -3.23283E-05
A6 = -1.88341E-07
A8 = 1.96755E-09
A10 = -1.43273E-11
Side 13
K = 0
A4 = -3.22004E-05
A6 = -9.60992E-07
A8 = 1.55589E-08
A10 = -2.82657E-10
14th page
K = 0
A4 = 3.53815E-06
A6 = -8.66214E-07
A8 = 1.17377E-08
A10 = -2.24402E-10
18th page
K = -1.27337
A4 = -1.58768E-05
A6 = -1.86624E-07
A8 = 6.94712E-10
A10 = -5.97184E-12
19th page
K = 0
A4 = 3.31640E-05
A6 = -1.06067E-07
A8 = -6.29723E-10
A10 = 0.

The glass material of the lens of the third lens group is assumed to be S-BSM 71 manufactured by OHARA.
Νd and θg, F of S-BSM71 are as follows from the published catalog.
νd = 53.02
θg, F = 0.5547
"Variable amount"
Variable amounts of data are shown in Table 3.

  FIG. 10, FIG. 11, and FIG. 12 sequentially show aberration diagrams of the third embodiment at the wide angle end, the intermediate focal length, and the telephoto end.

Example 4
Example 4 is the zoom lens shown in FIG.
f = 16.19450-45.75015 F = 3.62882-5.85754 ω = 42.69841-16.94375
Surface number R D Nd νd
1 33.04630 1.30000 1.84666 23.78
2 24.61909 5.03061 1.69680 55.53
3 136.08670 Variable A
4 66.82379 0.97000 2.00100 29.13
5 10.13620 6.58248
6 -27.08140 0.80000 1.69350 53.18
7 42.28382 0.10000
8 36.12687 4.06747 1.84666 23.78
9 -23.91703 Variable B
10 -19.22723 0.80000 1.60300 65.44 (S-PHM53)
11 -40.79376 Variable C
12 ∞ (Aperture) 1.45000
13 15.53437 3.73586 1.51633 64.06
14 -28.31772 0.10000
15 26.51545 3.96987 1.53172 48.84
16 -16.08335 1.45000 1.83400 37.16
17 21.49926 Variable D
18 18.61811 5.28649 1.58913 61.15
19 -19.32644 0.10000
20 50.34422 0.82401 1.90366 31.32
21 15.67976 Variable E
22 ∞ 0.70000 1.53770 66.60
23 ∞ 1.50000
24 ∞ 0.70000 1.50000 64.00
25 ∞.

"Aspheric data"
The aspheric data is shown below.

6th page
K = 0
A4 = -2.62797E-05
A6 = 2.15039E-07
A8 = 1.25881E-09
A10 = -3.37339E-11
A12 = -5.96466E-14
7th page
K = 0
A4 = -6.94415E-05
A6 = 2.98647E-07
A8 = -1.81245E-09
A10 = -2.26671E-11
Side 13
K = 0
A4 = -1.84404E-05
A6 = -9.86481E-08
A8 = 1.21421E-09
A10 = -2.38227E-11
14th page
K = 0
A4 = 9.50545E-06
A6 = 8.22895E-08
A8 = -9.41319E-10
A10 = -1.57178E-11
A12 = 0
18th page
K = -4.00213
A4 = 5.35275E-06
A6 = -6.14576E-08
A8 = -3.35757E-09
A10 = 3.63892E-11
19th page
K = -0.0203
A4 = 4.11207E-05
A6 = 6.45731E-08
A8 = -4.12993E-09
A10 = 4.1149E-11.

The glass material of the lens of the third lens group is assumed to be S-PHM53 manufactured by OHARA.
Νd and θg, F of S-PHM53 are as follows from the published catalog.
νd = 65.44
θg, F = 0.5401
"Variable amount"
Variable amounts of data are shown in Table 4.

  FIG. 14, FIG. 15, and FIG. 16 show aberration diagrams of Example 4 at the wide-angle end, intermediate focal length, and telephoto end, respectively.

"Example 5"
Example 5 is the zoom lens shown in FIG.
f = 16.146-53.84 F = 3.65-5.74 ω = 41.5-14.87
Surface number R D Nd νd
1 46.03179 1.30005 1.84666 23.78
2 31.22940 5.51888 1.77250 49.60
3 152.04501 Variable A
4 51.07120 0.97002 2.00100 29.13
5 10.77721 6.63709
6 -42.16678 0.79999 1.77030 47.40
7 38.75553 0.96368
8 30.38725 4.33203 1.84666 23.78
9 -29.02408 Variable B
10 -21.91807 0.80000 1.64850 53.02 (S-BSM71)
11 -79.56447 Variable C
12 ∞ (Aperture) 1.44994
13 18.62497 4.02774 1.51633 64.06
14 -25.81393 0.09995
15 20.81187 4.01271 1.51742 52.43
16 -19.74213 1.44999 1.83400 37.16
17 19.22015 Variable D
18 20.95766 5.30002 1.58913 61.15
19 -22.01066 0.10001
20 42.36060 0.79999 1.90366 31.32
21 16.44550 Variable E
22 ∞ 0.70000 1.53770 66.60
23 ∞ 1.50000
24 ∞ 0.70000 1.50000 64.00
25 ∞.

"Aspheric data"
The aspheric data is shown below.

6th page
K = 0
A4 = 5.52979E-05
A6 = -1.46723E-06
A8 = 1.40955E-08
A10 = -5.75258E-11
7th page
K = 0
A4 = 3.02092E-05
A6 = -1.53901E-06
A8 = 1.44769E-08
A10 = -6.26901E-11
Side 13
K = 0
A4 = -8.40542E-06
A6 = -4.37152E-07
A8 = 1.03740E-08
A10 = -2.45238E-10
14th page
K = 0
A4 = 2.47361E-05
A6 = -6.21729E-07
A8 = 1.37690E-08
A10 = -2.72842E-10
18th page
K = -0.92674
A4 = -1.83059E-05
A6 = -3.30349E-08
A8 = -2.28321E-09
A10 = -6.15846E-13
19th page
K = 0
A4 = 3.19375E-05
A6 = 3.31577E-08
A8 = -2.88956E-09
A10 = 0.

The glass material of the lens of the third lens group is assumed to be S-BSM 71 manufactured by OHARA.
Νd and θg, F of S-BSM71 are as follows from the published catalog.
νd = 53.02
θg, F = 0.5547
"Variable amount"
Variable amounts of data are shown in Table 5.

  FIG. 18, FIG. 19, and FIG. 20 show aberration diagrams in Example 5 at the wide-angle end, the intermediate focal length, and the telephoto end, respectively.

"Example 6"
Example 6 is the zoom lens shown in FIG.

f = 16.146 to 53.852 F = 3.62 to 5.77 ω = 41.53 to 14.87
Surface number R D Nd νd
1 52.97005 1.31000 1.84666 23.78
2 35.71101 5.48584 1.77250 49.60
3 189.65170 Variable A
4 57.34337 0.95497 2.00100 29.13
5 11.09490 6.36289
6 -52.53144 0.80001 1.77030 47.40
7 36.40322 1.16039
8 30.42534 4.23829 1.84666 23.78
9 -30.42507 Variable B
10 -22.85191 0.80000 1.64850 53.02 (S-BSM71)
11 -92.38759 Variable C
12 ∞ (Aperture) 1.40001
13 19.49107 3.32058 1.51633 64.06
14 -25.78639 0.11538
15 18.99577 4.01733 1.51742 52.43
16 -18.99577 1.40000 1.83400 37.16
17 18.99577 Variable D
18 19.38104 5.59999 1.58913 61.15
19 -23.21203 0.10000
20 34.69037 0.80000 1.90366 31.32
21 14.67162 Variable E
22 ∞ 0.70000 1.53770 66.60
23 ∞ 1.50000
24 ∞ 0.70000 1.50000 64.00
25 ∞.

"Aspheric data"
The aspheric data is shown below.

6th page
K = 0
A4 = 2.63554E-05
A6 = -1.09237E-06
A8 = 9.8447E-09
A10 = -3.41409E-11
7th page
K = 0
A4 = 2.93738E-06
A6 = -1.13624E-06
A8 = 1.01043E-08
A10 = -3.88306E-11
Side 13
K = 0
A4 = 3.21402E-07
A6 = -1.03872E-07
A8 = 6.34622E-09
A10 = -1.99948E-10
14th page
K = 0
A4 = 2.47699E-05
A6 = -2.4115E-07
A8 = 9.50458E-09
A10 = -2.36136E-10
18th page
K = -0.57855
A4 = -1.83484E-05
A6 = -2.90044E-08
A8 = -1.90061E-09
A10 = -5.50054E-12
19th page
K = -0.09961
A4 = 3.54974E-05
A6 = 3.43435E-08
A8 = -3.14805E-09.

The glass material of the lens of the third lens group is assumed to be S-BSM 71 manufactured by OHARA.
Νd and θg, F of S-BSM71 are as follows from the published catalog.
νd = 53.02
θg, F = 0.5547
"Variable amount"
The variable amount of data is shown in Table 6.

  FIG. 22, FIG. 23, and FIG. 24 sequentially show aberration diagrams of Example 6 at the wide-angle end, the intermediate focal length, and the telephoto end.

"Example 7"
Example 7 is the zoom lens shown in FIG.
f = 16.146-53.852 F = 3.61-5.76 ω = 41.53-14.87
Surface number R D Nd νd
1 53.02258 1.31000 1.84666 23.78
2 35.94362 5.46329 1.77250 49.60
3 188.67998 Variable A
4 54.87412 0.95512 2.00100 29.13
5 10.79646 6.44587
6 -51.91885 0.80000 1.74320 49.29
7 40.63394 1.06371
8 31.38598 4.08243 1.84666 23.78
9 -31.38598 Variable B
10 -23.00149 0.80000 1.65160 58.55 (S-LAL7)
11 -97.40089 Variable C
12 ∞ (Aperture) 1.39999
13 19.57334 3.29549 1.51633 64.06
14 -25.26589 0.10000
15 19.46405 3.89071 1.51742 52.43
16 -19.46405 1.40519 1.83400 37.16
17 19.46405 Variable D
18 19.69818 5.60000 1.58913 61.15
19 -22.10614 0.10000
20 38.97349 0.80019 1.90366 31.32
21 15.14672 Variable E
22 ∞ 0.70000 1.53770 66.60
23 ∞ 1.50000
24 ∞ 0.70000 1.50000 64.00
25 ∞.

"Aspheric data"
Aspheric data are listed below.

6th page
K = 0
A4 = 3.46877E-05
A6 = -1.27443E-06
A8 = 1.11921E-08
A10 = -4.40045E-11
7th page
K = 0
A4 = 6.8617E-06
A6 = -1.34447E-06
A8 = 1.13537E-08
A10 = -4.81564E-11
Side 13
K = 0
A4 = -1.2513E-06
A6 = -4.84014E-08
A8 = 5.40686E-09
A10 = -2.0620E-10
14th page
K = 0
A4 = 2.71708E-05
A6 = -2.3373E-07
A8 = 9.93932E-09
A10 = -2.54318E-10
18th page
K = -0.65075
A4 = -1.90482E-05
A6 = -3.34777E-08
A8 = -1.71693E-09
A10 = -5.56274E-12
19th page
K = -0.20854
A4 = 3.63343E-05
A6 = 2.45318E-08
A8 = -2.95008E-09.

The glass material of the lens of the third lens group is assumed to be S-LAL7 manufactured by OHARA.
Νd and θg, F of S-LAL7 are as follows from the published catalog.
νd = 58.55
θg, F = 0.5425
"Variable amount"
Variable amounts of data are shown in Table 7.

  FIG. 26, FIG. 27, and FIG. 28 sequentially show aberration diagrams of Example 7 at the wide-angle end, the intermediate focal length, and the telephoto end.

"Example 8"
Example 8 is the zoom lens shown in FIG.
f = 16.145 to 53.86 F = 3.64 to 5.75 ω = 41.53 to 15.0
Surface number R D Nd νd
1 51.57017 1.35033 1.84666 23.78
2 35.08789 5.69112 1.7725 49.6
3 182.91872 Variable A
4 44.57654 0.98972 2.001 29.13
5 10.55643 6.75921
6 -44.69477 0.80002 1.7432 49.29
7 47.5051 1.35366
8 32.75877 3.82977 1.84666 23.78
9 -32.75877 Variable B
10 -24.76086 0.8 1.6516 58.55 (S-LAL7)
11 -153.4119 Variable C
12 ∞ 1.40078
13 18.96748 3.75245 1.51633 64.06
14 -24.25341 0.09999
15 18.77954 4.04255 1.51742 52.43
16 -18.77954 1.3999 1.834 37.16
17 18.77954 Variable D
18 22.71409 5.00033 1.58913 61.15
19 -20.0266 0.10002
20 56.47649 0.79994 1.90366 31.32
21 17.45296 Variable E
22 ∞ 0.70000 1.53770 66.60
23 ∞ 1.50000
24 ∞ 0.70000 1.50000 64.00
25 ∞.

"Aspheric data"
The aspheric data is shown below.

The glass material of the lens of the third lens group is assumed to be S-LAL7 manufactured by OHARA.
Νd and θg, F of S-LAL7 are as follows from the published catalog.
νd = 58.55
θg, F = 0.5425
"Variable amount"
Variable amounts of data are shown in Table 8.

  FIG. 30, FIG. 31, and FIG. 32 sequentially show aberration diagrams of Example 8 at the wide-angle end, the intermediate focal length, and the telephoto end.

"Parameter values for conditional expressions"
Table 9 shows the values of the parameters of the conditional expressions in the above examples.

  As shown in Table 9, Examples 1 to 8 satisfy the conditions (1) to (6).

  In each example, the aberration is corrected well and the performance is good.

I First lens group II Second lens group
III Third lens group IV Fourth lens group
V 5th lens group
S Aperture stop

JP-A-3-228008 Japanese Patent No. 3716418 Japanese Patent No. 3397686 Japanese Patent No. 4401451 JP 2010-175594 A

Claims (6)

In order from the object side along the optical axis, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, A fifth lens unit having a positive refractive power, and an aperture stop disposed between the third lens unit and the fourth lens unit;
During zooming from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group is increased, the distance between the second lens group and the third lens group is increased, and the third lens group and the fourth lens are increased. The distance between the groups decreases, the distance between the fourth lens group and the fifth lens group decreases,
The third lens group is composed of one negative lens, and the negative lens is a negative meniscus lens having a concave surface facing the object side,
Focusing is performed by moving the third lens group in the optical axis direction
Radius of curvature of the object side surface of the third lens group: R31, Radius of curvature of the image side surface of the third lens group: R32: Focal length of the third lens group: F3, Composite focal length of the second and third lens groups at the telephoto end : F23w, combined focal length of the second and third lens groups at the telephoto end: F23t, focal length at the wide angle end: Fw, focal length at the telephoto end: Ft, √ (Fw × Ft): Fm, conditions:
(1) 1.0 <(R31-R32) / | F23w | <10.0
(2) 1.0 <(R31-R32) / | F23t | <10.0
(3) 1.4 <| F3 | / Fm <2.5
(6) 2.8 <Ft / Fw
A zoom lens characterized by satisfying The zoom lens according to claim 1.
Maximum image height: Y ′, focal length at wide angle end: Fw, conditions:
(5) 0.75 <Y ′ / Fw
A zoom lens characterized by satisfying The zoom lens according to claim 1 or 2,
Abbe number of material of one negative lens constituting the third lens group: νd is a condition:
(4) νd> 50
A zoom lens characterized by satisfying An information apparatus having a photographing function, comprising the zoom lens according to claim 1 as a photographing optical system. The information device according to claim 4, wherein
An information device having a photographing function, wherein an object image formed by a zoom lens is formed on a light receiving surface of an image sensor. The information device according to claim 5,
An information device having a photographing function, characterized by being configured as a portable information terminal device.

Images