JP2003035868A - Variable power group for zoom lens, zoom lens and camera device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a zoom lens used for digital image photography while keeping its high performance. SOLUTION: This zoom lens where a 1st group I having a negative focal distance, a 2nd group II having a positive focal distance, and a 3rd group III having a positive focal distance are arranged in order from an object side has a diaphragm S moving integrally with the 2nd group on the object side of the 2nd group. In the zoom lens, the 2nd group monotonously moves from an image side to the object side in the case of variable power from a short focus end to a long focus end, and the 1st group moves to compensate the fluctuation of an image surface position associated with the variable power. A variable power group constituted as the 2nd group and performing substantial variable power is constituted by arranging three lenses, that is, a positive lens whose surface having large curvature faces to the object side, a negative lens whose surface having large curvature faces to the image side and a positive lens in order from the object side, and the surface nearest to the object side and the surface nearest to the image side are made aspherical.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable power group, a zoom lens and a camera device in a zoom lens. INDUSTRIAL APPLICABILITY The present invention can be suitably applied to various photographing devices such as a silver salt camera, particularly a digital camera, a video camera, and an information device having a digital image photographing function.

[0002]

2. Description of the Related Art Digital image capturing has spread not only to conventional digital cameras, but also to mobile information terminal devices such as mobile phones, and the demands of users are widespread. Above all, high image quality and miniaturization are always desired by the user, and the weight occupies a large part in various requests. Therefore, the zoom lens used as a photographing lens is required to have both "high performance and small size".

To reduce the size of the zoom lens, it is necessary to shorten the total lens length (the distance from the lens surface closest to the object side to the image surface). Further, in a so-called "collapsible type" camera device that is compact when the lens is housed, it is also important to reduce the thickness of each group that moves during zooming in the optical axis direction in order to reduce the size when the lens is housed.

As a type of zoom lens suitable for miniaturization, a first group having a negative focal length, a second group having a positive focal length, and a third group having a positive focal length are arranged in order from the object side. Then, on the object side of the second lens unit, “a diaphragm that moves integrally with the second lens unit”
When zooming from the short focus end to the long focus end,
It is known that the second lens group moves monotonically from the image side to the object side, and the first lens group moves so as to correct the change in the image plane position due to the magnification change.

Japanese Unexamined Patent Application Publication No. 10-039214 is the earliest proposed zoom lens of the above type and discloses all the basic structures, but it is not always sufficient in terms of downsizing. The zoom lens of the above-mentioned type is improved and downsized is disclosed in JP-A-11-28795.
As disclosed in Japanese Patent Publication No. 3, the second lens group has only one aspherical surface, so that miniaturization is still insufficient and aberration correction cannot be said to be sufficient. Also, Japanese Patent Laid-Open No. 2000-08
Japanese Patent No. 91102 discloses a second group with a second example.
Although it is disclosed that the aberration is satisfactorily corrected by using the aspherical surface, the second group has a large thickness and is not necessarily advantageous for downsizing.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, it is an object of the present invention to further downsize while maintaining the high performance of a zoom lens used for digital image capturing.

[0007]

The "magnifying power group in a zoom lens" of the present invention includes "a first lens group having a negative focal length, a second lens group having a positive focal length, and a positive lens group in order from the object side". A third lens unit having a focal length is provided, and an aperture stop that moves integrally with the second lens unit is provided on the object side of the second lens unit, and the second lens unit moves toward the image side when zooming from the short focal length end to the long focal length end. In the zoom lens that moves monotonically from the object side to the object side, and the first group moves so as to correct the change in the image plane position due to zooming, the zooming group configured as the second group and performing substantial zooming It is.

The variable power group according to claim 1 has the following features. That is, the variable power group configured as the second group includes, in order from the object side, a positive lens having a surface having a large curvature facing the object side, a negative lens having a surface having a large curvature facing the image side, and a positive lens. And the surface closest to the object and the surface closest to the image are aspherical surfaces.

In the variable power group according to the first aspect, the thickness in the optical axis direction: L ₂ and the maximum image height: Y ′ are as follows: (1) 1.0 <(L ₂ / Y ′) <2 It is preferable to satisfy 0.5 (claim 2).

In the variable power group according to claim 1 or 2, when the radiuses of curvature of the object-side surface and the image-side surface of the positive lens closest to the image side are R ₃₁ and R ₃₂ , respectively, these conditions are: ) —0.4 <(R ₃₁ + R ₃₂ ) / (R ₃₁ −R ₃₂ ) <0.0 is preferable (claim 3). In this case, since the image side surface is an aspherical surface, the above radius of curvature: R ₃₂
Is the paraxial radius of curvature.

In the variable power group according to claim 1, 2 or 3, a positive lens closest to the object side and a negative lens following the positive lens may be cemented to form a cemented lens (claim 4), 3 The lenses may be independent lenses (Claim 5).

The variable power group according to claim 6 has the following features. That is, in the variable power group which is configured as the second group and which performs substantial variable power, the most object side surface and the most image side surface are aspherical surfaces, the thickness in the optical axis direction: L ₂ , and the maximum image height: Y ′ satisfies the condition: (1) 1.0 <(L ₂ /Y′)<2.5.

According to a sixth aspect of the present invention, in the variable power group, in order from the object side, a positive lens having a surface having a large curvature facing the object side, a negative lens having a surface having a large curvature facing the image side, a positive lens, and a positive lens are arranged. It is possible to have a four-sheet configuration in which four sheets are arranged (claim 7). In this case, the four lenses constituting the variable power group may be independent of each other, but "a positive lens closest to the object side and a negative lens following the positive lens may be integrated as a cemented lens" ( Claim 8).

According to the zoom lens of the present invention, "a first group having a negative focal length, a second group having a positive focal length, and a third group having a positive focal length are arranged in order from the object side, and a second group On the object side of the lens unit, there is an aperture stop that moves integrally with the second lens unit, and when zooming from the short focus end to the long focus end, the second lens unit moves monotonically from the image side to the object side 9. A zoom lens that performs a variable magnification, and the first group moves so as to correct the variation in the image plane position due to the variable magnification, and the second group is any one of claims 1 to 8 above. It is characterized in that a variable power group of is used (claim 9).

A first aspect of the zoom lens according to the present invention.
The group is “in order from the object side, at least one negative lens having a large curvature surface facing the image side and at least one positive lens having a large curvature surface facing the object side are arranged and arranged on the object side. Among the one or more negative lenses, the image-side surface of the negative lens located closest to the image side is an aspherical surface ”(claim 10).

The first group in the zoom lens according to the tenth aspect is defined as "a negative meniscus lens having a convex surface facing the object side, a negative lens having a large curvature surface facing the image side, and a curvature facing the object side in order from the object side". The three-lens structure in which the positive lens having the large surface of is arranged is provided, and the image-side surface of the second negative lens arranged from the object side can be made aspheric (claim 11). In this case, the focal length of the negative meniscus lens arranged closest to the object side of the first group is f _L1 , and the focal length of the negative lens arranged second from the object side of the first group is f _L2 : 3) It is preferable that 0.7 <(f _L1 / f _L2 ) <2.0 is satisfied (claim 12).

In the zoom lens according to the tenth aspect of the present invention, the first lens group is arranged in order from the object side: a negative meniscus lens having a convex surface facing the object side and a positive lens having a large curvature surface facing the object side. The image-side surface of the negative meniscus lens can be an aspherical surface (claim 13).

The third group in the zoom lens according to any one of claims 9 to 13 is constituted by a positive lens having a surface having a large curvature facing the object side, and has at least one aspherical surface. It is possible (claim 14).

In the zoom lens according to any one of claims 9 to 14, it is preferable that the number of constituent lenses of the entire system is 8 or less (claim 15).

A camera device according to the present invention has the zoom lens according to any one of claims 9 to 15 as a "shooting zoom lens" (claim 1).
6). The camera device according to the sixteenth aspect of the present invention can be configured such that the zoom lens for photographing is housed in a retractable manner (the seventeenth aspect).

The camera device according to claim 16 or 17 can have a "function of using a photographed image as digital information" (claim 18), and in this case, the light receiving element for receiving the image by the zoom lens has 2 million pixels. It can be the above (claim 19).

The camera device according to claims 18 and 19 can be a "portable information terminal device" (claim 2).
0).

In a zoom lens composed of three groups of negative, positive, and positive like the zoom lens of the present invention, generally, when the magnification is changed from the short focal end to the long focal end, the second lens unit moves from the image side to the object side. It moves monotonically to the side, and the first group moves so as to correct the fluctuation of the image plane position due to the magnification change. Most of the zoom function is the second
The third group is mainly provided with a function of keeping the exit pupil away from the image plane.

In order to realize a zoom lens having a small number of various aberrations and a high resolution, it is necessary to suppress aberration fluctuations due to zooming, but in particular, a zooming group that performs substantial zooming,
That is, the second lens group, which is the "main zooming group", needs to be satisfactorily corrected for aberrations over the entire zooming range.

The good correction of the aberration of the second lens group is basically as follows.
This can be done by increasing the number of lenses forming the second group, but an increase in the number of constituent lenses leads to an “increase in the thickness in the optical axis direction” of the second group, and sufficient miniaturization cannot be achieved, resulting in cost reduction. Will also increase.

Therefore, according to the first to fifth aspects of the present invention, the second lens group, which is a main variable power group, includes, in order from the object side, a positive lens having a surface having a large curvature facing the object side and a surface having a large curvature facing the image side. A negative lens and a positive lens facing each other are arranged, and the most object side surface and the most image side surface of the second group are aspherical surfaces.

That is, the second group is made to be a triplet type and "minimum number of constituents capable of both correction of chromatic aberration and correction of curvature of field" is realized to realize miniaturization, and two aspherical surfaces are used to provide flexibility. It achieves high performance with high aberration correction.

The most object-side surface of the second group is "near the diaphragm".
Therefore, the on-axis and off-axis light flux passes with almost no separation,
The aspherical surface provided on this surface mainly contributes to correction of spherical aberration and coma. Since the most image-side surface of the second group is away from the diaphragm, the on-axis and off-axis light fluxes are separated to some extent. Therefore, the aspherical surface provided on this surface contributes to the correction of astigmatism and the like.

As described above, the two aspherical surfaces are used for the "most object-side surface and the most image-side surface", and the effects produced by the respective aspherical surfaces are made different, so that the degree of freedom in correction of monochromatic aberrations is increased. Can be dramatically increased, and even with a triplet configuration in which the number of sheets is small, it is possible to sufficiently correct various aberrations including chromatic aberration.

In the invention according to claim 1, since the second group has a three-element structure, it is well suited for downsizing. However, in order to achieve further downsizing, it is preferable that the condition (1) is satisfied. . If the parameter: L ₂ / Y 'is 2.5 or more, which is the upper limit value, the thickness of the second lens unit in the optical axis direction increases, and it becomes impossible to achieve sufficient miniaturization. On the contrary, when the parameter: L ₂ / Y 'becomes lower than 1.0 which is the lower limit value, the "most image side surface" of the second group approaches the diaphragm, and the above "correction of astigmatism" is performed. The effect of the aspherical surface cannot be sufficiently exerted, and it becomes difficult to correct various aberrations such as astigmatism.

[0031] If the second group and such as the "three-element", the condition (2) is narrower than the condition (1 ') satisfies 1.0 _<(L 2 /Y')<2.0 As a result, it becomes possible to realize further miniaturization.

If the configuration of the second group is a triplet type, the object-side surface (aspherical surface) of the positive lens closest to the object side of the second group and the image-side surface of the subsequent negative lens are “mutually opposite to each other”. There will be a large exchange of aberrations. " For this reason, the influence of the assembling error (decentering or the like) of these two lenses on the imaging performance tends to be large.

Regarding this point, by assembling these two lenses, it is possible to suppress the assembly error itself (claim 4).

However, according to the first aspect of the present invention, the aspherical surface is also used for the positive lens closest to the image side in the second group, and the assembling error of the positive lens closest to the image side has a great influence on the imaging performance. . The condition (2) should be satisfied in order to suppress the influence on the imaging performance due to the assembling error of the “most image side positive lens” of the second group.

The condition (2) is that "the exchange of aberrations is completed as much as possible between the object-side surface and the image-side surface (aspherical surface)" of the most image-side positive lens in the second lens group, and This is to prevent the positional relationship with the lens from becoming severe.

Parameter: (R ₃₁ + R ₃₂ ) / (R ₃₁ -R ₃₂ )
When the upper limit is 0.0 or more, the aberration generated on the image side surface of the positive lens closest to the image side is larger than the aberration generated on the object side surface, and the lower limit value is −0.4 or less. Then, the aberration generated on the object-side surface becomes larger than the aberration generated on the image-side surface, and in either case, "the exchange of aberrations with other lens surfaces" increases, so this (second group Of the positive lens on the most image side has a great influence on the imaging performance.

As described above, in the inventions according to claims 1 to 5, the second group is composed of three pieces. However, if the above condition (1) is satisfied, the condition (1) will change the size of the second group. Because of the limitation, even if the second group is configured with a configuration other than the three-element configuration, the requirements for high performance and miniaturization can be satisfied.

That is, in this case, as in the variable power groups according to claims 7 and 8, a positive lens having a surface with a large curvature facing the object side and a surface having a large curvature facing the image side are arranged in this order from the object side. 4 composed of four lenses, a negative lens, a positive lens, and a positive lens
It can be made up of a single lens element, and "a positive lens closest to the object side and a negative lens following it are integrated as a cemented lens".
You can also do it.

As described above, the zoom lens according to the ninth aspect is a variable magnification group of three groups, and any one of the first to eighth aspects.
Although the variable power group described in (1) is used, in order to “better correct” each aberration in the zoom lens, the first group is arranged “in order from the object side” as in the invention of claim 10. , Having at least one negative lens having a large curvature surface facing the image side and at least one positive lens having a large curvature surface facing the object side, and at least one negative lens arranged on the object side. Of the lenses, the image-side surface of the negative lens closest to the image side is aspherical. ”

By making the first group have such a constitution, "the curvature of field can be made small", and by making the "a surface having a large refraction angle of off-axis rays" an aspherical surface, a particularly short focal point can be obtained. It is possible to suppress distortion at the edges.

In this case, as in the zoom lens according to claim 11, the first group is composed of “a negative meniscus lens having a convex surface facing the object side and a negative lens having a large curvature surface facing the image side in order from the object side”. And a positive lens having a surface having a large curvature facing the object side is arranged, and the image side surface of the second negative lens arranged from the object side is an aspherical surface. "
By satisfying the condition (3) as in the invention described above, it is possible to reduce the influence of the aspherical surface forming error on the imaging performance and to effectively exhibit the effect of the aspherical surface.

That is, in condition (3), the parameters:
(f _L1 / f _L2 ) represents the “power ratio” of the two negative lenses in the first group, and this parameter has an upper limit value of 2.0.
In the above case, the power of the second negative lens having an aspherical surface becomes stronger, the influence of the manufacturing error of the aspherical surface on the imaging performance becomes large, and the thickness difference between the center and the periphery of the lens becomes large. The difficulty of forming a lens by molding becomes high. Meanwhile, the parameters:
When (f _L1 / f _L2 ) is lower than or equal to the lower limit value of 0.7, the power of the second negative lens having an aspherical surface becomes weak, and the refraction angle of the off-axis ray on the image side surface becomes small. The effect of the spherical surface is diminished.

More preferably, it is preferable that the following condition, which is narrower than the condition (3), is satisfied: (3 ') 0.7 <(f _L1 / f _L2 ) <1.5.

In the zoom lens according to the thirteenth aspect, the first lens unit is arranged in order from the object side: a negative meniscus lens having a convex surface facing the object side, and a positive lens having a large curvature surface facing the object side. The image-side surface of the negative meniscus lens can be an aspherical surface.
By forming the group into such a two-piece structure, it is advantageous in downsizing with a simpler structure. Further, the above claims 11 and 1
When the first group is composed of three lenses as in the zoom lens described in item 2, "the aberration correction capability is enhanced, which is advantageous for widening the field angle".

It is desirable that the third lens unit have a structure such as a zoom lens system according to claim 14 in which it is composed of a positive lens having a surface having a large curvature facing the object side and at least one surface thereof is an aspherical surface. With such a configuration, it is possible to more favorably correct off-axis aberrations such as astigmatism while minimizing the thickness of the third lens unit.

Although the third lens unit may be fixed during zooming, it can be "moved by a small amount to increase the degree of freedom of aberration correction".

[0047]

BEST MODE FOR CARRYING OUT THE INVENTION Specific numerical examples of the zoom lens of the present invention will be shown below. In each of the embodiments, the aberration is sufficiently corrected, and it is possible to deal with the light receiving element having 2 million pixels to 3 million pixels. It is apparent from the examples that by constructing the zoom lens as in the present invention, it is possible to secure a very small size while ensuring a very good image performance.

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 R: radius of curvature D: surface spacing Nd: refractive index νd: Abbe number K: aspherical conical constant A ₄ : fourth-order aspherical coefficient A ₆ : 6th-order aspherical coefficient A ₈ : 8th-order aspherical coefficient A ₁₀ : 10th-order aspherical coefficient A ₁₂ : 12th-order aspherical coefficient A ₁₄ : 14th-order aspherical coefficient A ₁₆ : 16th-order aspherical coefficient Spherical coefficient A ₁₈ : 18th-order aspherical coefficient For an aspherical surface, the reciprocal of the paraxial curvature radius (paraxial curvature) is C (= 1).
/ R), the height from the optical axis is H, and the depth in the optical axis direction is X, using the above-mentioned conical constant and aspherical coefficient, it is defined by the following well-known formula. X = CH ² / [1 + √ {1- (1 + K) C ² H ² }] + A ₄・ H ⁴ + A ₆・ H ⁶ + A ₈・ H ⁸ + A
₁₀・ H ¹⁰ + A ₁₂・ H ¹² + A ₁₄・ H ¹⁴ + A ₁₆・ H ¹⁶ + A ₁₈・ H ^{18 In} addition, "*" is added to the surface number for surfaces that have adopted an aspherical surface. Further, the unit of the quantity having the dimension of length is "mm".

[0049]

Examples Example 1 f = 4.33 to 10.28, F = 2.73 to 4.10, ω = 40.29 to 18.97 Surface number RD Nd νd Remark 01 40.685 1.00 1.77250 49.62 First lens 02 7.403 0.95 03 14.152 1.00 1.74330 49.33 Second lens 04 * 4.479 1.41 05 8.729 2.01 1.72825 28.32 3rd lens 06 ∞ Variable (A) 07 Aperture 1.00 08 * 5.652 3.87 1.74400 44.90 4th lens 09 -14.306 0.80 1.80518 25.46 5th lens 10 5.615 0.35 11 11.620 1.55 1.63854 55.45 6th lens 12 * -13.784 Variable (B) 13 * 13.554 1.65 1.48749 70.44 7th lens 14 -98.025 Variable (C) 15 ∞ 3.25 1.51680 64.20 Various filters 16 ∞ 1st to 3rd lenses make up the 1st group, and 4th to 4th The sixth lens constitutes the second group, and the seventh lens constitutes the third group. The fourth lens and the fifth lens in the second group are cemented lenses.

Aspherical fourth surface K = 0.0, A ₄ = -1.37618 × 10 ^-3 , A ₆ = -5.03401 × 10 ^-5 , A ₈ = 1.57384 × 10 ^-6 , A ₁₀ = -2.30976 × 10 ^-7 , A ₁₂ = -3.26464 × 10 ^-9 , A ₁₄ = 4.00882 × 10 ^-10 , A ₁₆ = 1.97709 × 10 ^-11 , A ₁₈ = -1.97909 × 10 ^-12 Eighth surface K = 0.0, A ₄ = -3.10301 × 10 ^-4 , A ₆ = -9.60865 × 10 ^-6 , A ₈ = 1.38603 × 10 ^-6 , A ₁₀ = -1.17724 × 10 ^-7 12th surface K = 0.0, A ₄ = 4.87200 × 10 ^-4 , A ^{_{6 = 4.48027 × 10 -5, A}} 8 = -1.67451 × 10 -6, A 10 = 4.32123 × 10 -7 13th surface _{K = 0.0, A 4 = -2.44272} × 10 -4, A 6 = 2.13490 × 10 - ⁵ , A ₈ = -1.60 140 × 10 ^-6 , A ₁₀ = 5.24693 × 10 ^-8 Variable amount Short focal length Intermediate focal length Long focal length f = 4.33 f = 6.64 f = 10.28 A 11.640 5.480 1.400 B 1.440 4.890 10.180 C 3.096 2.892 2.559 Conditional expression value (L ₂ /Y')=1.88 (R ₃₁ + R ₃₂ ) / (R ₃₁ -R ₃₂ ) =-0.085 (f _L1 / f _L2 ) = 1.29.

Example 2 f = 4.33 to 10.28, F = 2.71 to 4.06, ω = 40.30 to 18.94 Surface number RD Nd νd Remark 01 42.748 1.00 1.77250 49.62 1st lens 02 7.443 0.89 03 13.728 1.00 1.74330 49.33 2nd lens 04 * 4.394 1.50 05 8.857 2.00 1.72825 28.32 3rd lens 06 ∞ Variable (A) 07 Aperture 1.00 08 * 5.337 2.41 1.74400 44.90 4th lens 09 -198.170 0.52 10 -42.607 0.88 1.80518 25.46 5th lens 11 4.924 0.21 12 6.330 2.51 1.51680 64.20 4th lens 6 lenses 13 * -12.158 Variable (B) 14 * 13.923 1.68 1.48749 70.44 7th lens 15 -117.275 Variable (C) 16 ∞ 3.25 1.51680 64.20 Various filters 17 ∞ The 1st to 3rd lenses make up the 1st group, and the 1st group The fourth to sixth lenses constitute the second group, and the seventh lens constitutes the third group.

Aspherical fourth surface K = 0.0, A ₄ = -1.42635 × 10 ^-3 , A ₆ = -6.33122 × 10 ^-5 , A ₈ = 2.18856 × 10 ^-6 , A ₁₀ = -1.81517 × 10 ^-7 , A ₁₂ = -1.54734 × 10 ^-9 , A ₁₄ = 5.33510 × 10 ^-10 , A ₁₆ = 7.16 118 × 10 ^-11 , A ₁₈ = -4.28124 × 10 ^-12 8th surface K = 0.0, A ₄ = -2.71616 × 10 ^-4 , A ₆ = -1.37281 × 10 ^-5 , A ₈ = 2.07664 × 10 ^-6 , A ₁₀ = -1.81165 × 10 ^-7 13th surface K = 0.0, A ₄ = 9.17882 × 10 ^-4 , A ^{_{6 = 5.21195 × 10 -5, A}} 8 = -1.05410 × 10 -6, A 10 = 3.21835 × 10 -7 14th surface _{K = 0.0, A 4 = -2.69023} × 10 -4, A 6 = 3.06885 × 10 - ⁵ , A ₈ = -2.70949 × 10 ^-6 , A ₁₀ = 9.24 380 × 10 ^-8 Variable amount Short focal length Intermediate focal length Long focal length f = 4.33 f = 6.64 f = 10.28 A 11.680 5.480 1.400 B 1.440 4.850 10.180 C 3.044 2.873 2.528 Conditional expression value (L ₂ / Y ') = 1.87 (R ₃₁ + R ₃₂ ) / (R ₃₁ -R ₃₂ ) = -0.315 (f _L1 / f _L2 ) = 1.30.

Example 3 f = 4.33 to 10.28, F = 2.67 to 4.03, ω = 40.31 to 18.96 Surface number RD Nd νd Remark 01 52.284 1.00 1.77250 49.62 First lens 02 7.548 0.90 03 14.553 1.00 1.74330 49.33 Second lens 04 * 4.429 1.45 05 9.086 2.11 1.72825 28.32 3rd lens 06 -123.655 Variable (A) 07 Aperture 1.00 08 * 5.316 2.25 1.74400 44.90 4th lens 09 -545.787 0.47 10 -38.991 1.18 1.80518 25.46 5th lens 11 4.987 0.19 12 6.737 2.27 1.51680 64.20 6th lens 13 * -11.295 Variable (B) 14 * 13.622 1.73 1.48749 70.44 7th lens 15 -75.425 Variable (C) 16 ∞ 3.25 1.51680 64.20 Various filters 17 ∞ The 1st to 3rd lenses make up the 1st group, The fourth to sixth lenses form the second group, and the seventh lens forms the third group.

Aspherical fourth surface K = 0.0, A ₄ = -1.52225 × 10 ^-3 , A ₆ = -4.90276 × 10 ^-5 , A ₈ = -3.89047 × 10 ^-7 , A ₁₀ = 1.40729 × 10 ^-7 , A ₁₂ = -3.52907 × 10 ^-8 , A ₁₄ = 1.18808 × 10 ^-9 , A ₁₆ = 5.42840 × 10 ^-11 , A ₁₈ = -3.71221 × 10 ^-12 Eighth surface K = 0.0, A ₄ = -2.57172 × 10 ^-4 , A ₆ = -1.36917 × 10 ^-5 , A ₈ = 2.21542 × 10 ^-6 , A ₁₀ = -1.81900 × 10 ^-7 13th surface K = 0.0, A ₄ = 8.29889 × 10 ^-4 , A ^{_{6 = 4.54452 × 10 -5, A}} 8 = -2.92852 × 10 -7, A 10 = 3.36336 × 10 -7 14th surface _{K = 0.0, A 4 = -2.39053} × 10 -4, A 6 = 2.27231 × 10 - ⁵ , A ₈ = -1.86944 × 10 ^-6 , A ₁₀ = 6.13185 × 10 ^-8 Variable amount Short focal length Intermediate focal length Long focal length f = 4.33 f = 6.64 f = 10.28 A 11.600 5.420 1.380 B 1.440 5.040 10.700 C 3.191 2.996 2.556 Conditional expression value (L ₂ / Y ') = 1.82 (R ₃₁ + R ₃₂ ) / (R ₃₁ -R ₃₂ ) =-0.253 (f _L1 / f _L2 ) = 1.29.

Example 4 f = 4.33 to 10.30, F = 2.71 to 4.04, ω = 40.29 to 18.95 Surface number RD Nd νd Remark 01 29.129 1.00 1.77250 49.62 First lens 02 6.828 1.16 03 16.225 1.00 1.74330 49.33 Second lens 04 * 4.651 1.47 05 9.174 2.39 1.74077 27.76 3rd lens 06 ∞ Variable (A) 07 Aperture 1.00 08 * 5.233 2.76 1.72342 37.99 4th lens 09 -19.253 0.16 10 -13.695 0.80 1.80518 25.46 5th lens 11 4.961 0.18 12 6.324 2.98 1.51680 64.20 4th lens 6 lenses 13 * -10.432 Variable (B) 14 * 13.397 1.60 1.48749 70.44 7th lens 15 153.379 Variable (C) 16 ∞ 3.25 1.51680 64.20 Various filters 17 ∞ The 1st to 3rd lenses make up the 1st group, and the 4th group ~ The sixth lens constitutes the second group, and the seventh lens constitutes the third group.

Aspherical fourth surface K = 0.0, A ₄ = -1.27929 × 10 ^-3 , A ₆ = -4.75375 × 10 ^-5 , A ₈ = 1.78640 × 10 ^-6 , A ₁₀ = -2.09707 × 10 ^-7 , A ₁₂ = -3.99557 × 10 ^-9 , A ₁₄ = 8.29203 × 10 ^-10 , A ₁₆ = -2.46067 × 10 ^-11 , A ₁₈ = -3.28212 × 10 ^-13 8th surface K = 0.0, A ₄ =- 2.23927 × 10 ^-4 , A ₆ = -9.69866 × 10 ^-6 , A ₈ = 1.89347 × 10 ^-6 , A ₁₀ = -1.43 145 × 10 ^-7 13th surface K = 0.0, A ₄ = 8.10959 × 10 ^-4 , A ₆ = 4.46654 × 10 ^-5 , A ₈ = -1.33415 × 10 ^-6 , A ₁₀ = 3.10407 × 10 ^-7 14th surface K = 0.0, A ₄ = -2.22347 × 10 ^-4 , A ₆ = 2.09486 × 10 ^-5 , A ₈ = -1.79477 × 10 ^-6 , A ₁₀ = 6.32978 × 10 ^-8 Variable amount Short focal length Intermediate focal length Long focal length f = 4.33 f = 6.64 f = 10.30 A 11.700 5.410 1.300 B 1.450 5.040 10.740 C 3.520 3.254 2.651 Numerical value of conditional expression (L ₂ / Y ') = 1.97 (R ₃₁ + R ₃₂ ) / (R ₃₁ -R ₃₂ ) = -0.245 (f _L1 / f _L2 ) = 1.29.

Example 5 f = 4.33 to 10.28, F = 2.70 to 4.03, ω = 40.29 to 18.97 Surface number RD Nd νd Remark 01 26.338 1.00 1.77250 49.62 First lens 02 5.957 1.15 03 11.354 1.00 1.74330 49.33 Second lens 04 * 4.800 1.68 05 9.326 1.89 1.74077 27.76 3rd lens 06 76.543 Variable (A) 07 Aperture 1.00 08 * 5.240 2.97 1.72342 37.99 4th lens 09 -17.637 0.20 10 -11.727 0.81 1.80518 25.46 5th lens 11 5.109 0.17 12 6.368 2.50 1.51680 64.20 4th lens 6 lenses 13 * -10.112 Variable (B) 14 * 13.474 1.60 1.48749 70.44 7th lens 15 164.596 Variable (C) 16 ∞ 3.25 1.51680 64.20 Various filters 17 ∞ The 1st to 3rd lenses make up the 1st group, and the 4th group ~ The sixth lens constitutes the second group, and the seventh lens constitutes the third group.

Aspherical fourth surface K = 0.0, A ₄ = -1.18340 × 10 ^-3 , A ₆ = -5.15513 × 10 ^-5 , A ₈ = 2.55275 × 10 ^-6 , A ₁₀ = -2.44284 × 10 ^-7 , A ₁₂ = -3.45686 × 10 ^-9 , A ₁₄ = 1.00396 × 10 ^-9 , A ₁₆ = -4.09624 × 10 ^-11 , A ₁₈ = 2.60442 × 10 ^-13 Eighth surface K = 0.0, A ₄ = -2.06641 × 10 ^-4 , A ₆ = -6.64 406 × 10 ^-6 , A ₈ = 1.79604 × 10 ^-6 , A ₁₀ = -1.27500 × 10 ^-7 13th surface K = 0.0, A ₄ = 1.00672 × 10 ^-3 , A ^{_{6 = 5.77600 × 10 -5, A}} 8 = -1.35110 × 10 -6, A 10 = 4.73799 × 10 -7 14th surface _{K = 0.0, A 4 = -2.40787} × 10 -4, A 6 = 3.74236 × 10 - ⁵ , A ₈ = -3.77 197 × 10 ^-6 , A ₁₀ = 1.389 75 × 10 ^-7 Variable amount Short focal length Intermediate focal length Long focal length f = 4.33 f = 6.64 f = 10.28 A 11.840 5.630 1.530 B 1.660 5.160 10.570 C 3.306 3.072 2.665 numerical values in conditional expressions _{(L 2 / Y ') =} 1.90 (R 31 + R 32) / (R 31 -R 32) = -0.227 (f L1 / f L2) = 0.851.

Example 6 f = 4.33 to 10.28, F = 2.75 to 4.08, ω = 40.30 to 19.03 Surface number RD Nd νd Remark 01 18.512 1.00 1.77250 49.62 First lens 02 6.948 0.99 03 13.261 1.00 1.74330 49.33 Second lens 04 * 4.130 1.63 05 7.992 1.76 1.84666 23.78 3rd lens 06 21.770 Variable (A) 07 Aperture 1.00 08 * 5.666 3.23 1.72342 37.99 4th lens 09 -10.575 0.80 1.80518 25.46 5th lens 10 5.648 0.31 11 11.807 1.70 1.51680 64.20 6th lens 12- 11.807 0.10 13 ∞ 1.34 1.51680 64.20 7th lens 14 * -15.216 Variable (B) 15 * 11.050 1.64 1.48749 70.44 8th lens 16 47.539 Variable (C) 17 ∞ 3.25 1.51680 64.20 Various filters 18 ∞ 1st-3rd lens The first lens group constitutes the fourth lens group, the fourth lens group to the seventh lens group constitutes the second lens group, and the eighth lens group constitutes the third lens group. The fourth lens and the fifth lens in the second group are cemented lenses.

Aspherical fourth surface K = 0.0, A ₄ = -1.36732 × 10 ^-3 , A ₆ = -6.93407 × 10 ^-5 , A ₈ = -7.84082 × 10 ^-7 , A ₁₀ = 2.83 825 × 10 ^-7 , A ₁₂ = -5.78 120 × 10 ^-8 , A ₁₄ = -7.22 128 × 10 ^-10 , A ₁₆ = 4.13152 × 10 ^-10 , A ₁₈ = -1.85992 × 10 ^-11 8th surface K = 0.0, A ₄ =- 4.08236 × 10 ^-4 , A ₆ = -7.50989 × 10 ^-6 , A ₈ = 7.45071 × 10 ^-7 , A ₁₀ = -9.85596 × 10 ^-8 14th surface K = 0.0, A ₄ = 6.16408 × 10 ^-5 , A ₆ = 4.52472 × 10 ^-6 , A ₈ = 2.22316 × 10 ^-7 , A ₁₀ = -1.94698 × 10 ^-8 Fifteenth surface K = 0.0, A ₄ = -2.44412 × 10 ^-4 , A ₆ = 1.88531 × 10 ^-5 , A ₈ = -1.480 17 × 10 ^-6 , A ₁₀ = 4.92 294 × 10 ^-8 Variable amount Short focal length Intermediate focal length Long focal length f = 4.33 f = 6.64 f = 10.28 A 10.380 5.120 1.400 B 1.450 5.600 10.980 C 3.442 2.939 2.873 Conditional expression value (L ₂ / Y ') = 2.14 (f _L1 / f _L2 ) = 1.77.

Example 7 f = 4.33 to 10.18, F = 2.73 to 4.00, ω = 40.30 to 19.19 Surface number RD Nd νd Remark 01 29.593 1.25 1.77250 49.62 1st lens 02 7.058 1.20 03 17.247 1.10 1.74330 49.33 2nd lens 04 * 4.563 1.30 05 8.485 2.16 1.72825 28.32 3rd lens 06 ∞ Variable (A) 07 Aperture 1.00 08 * 5.283 2.61 1.72342 37.99 4th lens 09 -20.081 0.29 10 -12.075 0.81 1.80518 25.46 5th lens 11 5.253 0.31 12 8.812 1.35 1.58913 61.25 4th lens 6 lens 13 20.251 0.10 14 12.502 1.73 1.48749 70.44 7th lens 15 * -8.992 Variable (B) 16 * 13.337 1.65 1.48749 70.44 8th lens 17 463.779 Variable (C) 18 ∞ 3.25 1.51680 64.20 Various filters 19 ∞ 1st to 3rd The lenses form the first group, the fourth to seventh lenses form the second group, and the eighth lens forms the third group.

Aspherical fourth surface K = 0.0, A ₄ = -1.29720 × 10 ^-3 , A ₆ = -5.09824 × 10 ^-5 , A ₈ = 1.81023 × 10 ^-6 , A ₁₀ = -2.10769 × 10 ^-7 , A ₁₂ = -4.76553 × 10 ^-9 , A ₁₄ = 8.28677 × 10 ^-10 , A ₁₆ = -2.46190 × 10 ^-11 , A ₁₈ = -4.1997 8 × 10 ^-13 Eighth surface K = 0.0, A ₄ =- 1.98718 × 10 ^-4 , A ₆ = -947779 × 10 ^-6 , A ₈ = 2.05528 × 10 ^-6 , A ₁₀ = -1.77908 × 10 ^-7 15th surface K = 0.0, A ₄ = 5.86592 × 10 ^-4 , A ₆ = 3.85335 × 10 ^-5 , A ₈ = -2.22078 × 10 ^-6 , A ₁₀ = 1.73297 × 10 ^-7 16th surface K = 0.0, A ₄ = -1.97840 × 10 ^-4 , A ₆ = 1.55183 × 10 ^-5 , A ₈ = -1.27 195 × 10 ^-6 , A ₁₀ = 4.39912 × 10 ^-8 Variable amount Short focal length Intermediate focal length Long focal length f = 4.33 f = 6.63 f = 10.18 A 11.860 5.530 1.400 B 1.450 5.230 10.810 C 3.570 3.241 2.731 Numerical value of conditional expression (L ₂ / Y ') = 2.06 (f _L1 / f _L2 ) = 1.42.

Example 8 f = 5.46 to 10.29, F = 2.76 to 3.64, ω = 33.92 to 19.03 Surface number RD Nd νd Remark 01 128.673 1.00 1.80610 40.74 First lens 02 * 4.108 1.50 03 8.797 1.75 1.84666 23.78 Second lens 04 56.875 Variable (A) 05 Aperture 1.00 06 * 5.276 2.39 1.72342 37.99 3rd lens 07 -16.390 0.23 08 -10.483 0.80 1.80518 25.46 4th lens 09 5.803 0.21 10 7.974 2.29 1.51680 64.20 5th lens 11 * -9.846 Variable (B) 12 * 13.220 1.55 1.48749 70.44 6th lens 13 132.376 Variable (C) 14 ∞ 3.25 1.51680 4.20 Various filters 15 ∞ The first and second lenses form the first group, and the third to fifth lenses form the second group. , The sixth lens constitutes the third group.

Aspherical second surface K = 0.0, A ₄ = -1.41341 × 10 ^-3 , A ₆ = -8.23203 × 10 ^-5 , A ₈ = 3.51562 × 10 ^-6 , A ₁₀ = -4.08043 × 10 ^-7 , A ₁₂ = -2.02424 × 10 ^-8 , A ₁₄ = 1.46185 × 10 ^-9 , A ₁₆ = 8.49258 × 10 ^-11 , A ₁₈ = -8.85 489 × 10 ^-12 6th surface K = 0.0, A ₄ = -1.06275 × 10 ^-4 , A ₆ = 7.68066 × 10 ^-6 , A ₈ = 1.00953 × 10 ^-6 , A ₁₀ = -4.21879 × 10 ^-8 11th surface K = 0.0, A ₄ = 9.01094 × 10 ^-4 , A ₆ = 6.60691 × 10 ^-5 , A ₈ = -4.27954 × 10 ^-7 , A ₁₀ = 5.21148 × 10 ^-7 12th surface K = 0.0, A ₄ = -3.07368 × 10 ^-4 , A ₆ = 2.58407 × 10 ^-5 , A ₈ = -1.98853 × 10 ^-6 , A ₁₀ = 6.58622 × 10 ^-8 Variable amount Short focal length Intermediate focal length Long focal length f = 5.46 f = 7.50 f = 10.29 A 10.010 5.730 2.280 B 1.460 4.390 7.200 C 4.540 4.367 4.954 Conditional expression value (L ₂ / Y ') = 1.69 (R ₃₁ + R ₃₂ ) / (R ₃₁ -R ₃₂ ) = -0.105.

1 to 8 sequentially show the "lens arrangement at the short focal end" of the zoom lenses of Examples 1 to 8 and the movement of each group due to zooming to the long focal end. . In these figures, "I" is the first group and "II" is the second group.
Group, "III" shows the third group, "S" is the aperture, "F"
Indicates various filters. In each of the embodiments, in order to “increase the degree of freedom in aberration correction”, the third group III is moved by a small amount during zooming.

Aberration curve diagrams at the short focal length end, the intermediate focal length, and the long focal length end relating to Example 1 are sequentially shown in FIGS. Aberration curve diagrams at the short focal length end, the intermediate focal length, and the long focal length end relating to the second embodiment are sequentially shown in FIGS.

Aberration curve diagrams at the short focal length end, the intermediate focal length, and the long focal length end relating to Example 3 are sequentially shown in FIGS. Short focal length, intermediate focal length,
Aberration curve diagrams at the long focus end are sequentially shown in FIGS.

Aberration curve diagrams at the short focal length end, the intermediate focal length, and the long focal length end relating to the fifth embodiment are sequentially shown in FIGS. Short focal length, intermediate focal length,
Aberration curve diagrams at the long focus end are sequentially shown in FIGS.

Aberration curve diagrams at the short focal length end, the intermediate focal length, and the long focal length end relating to Example 7 are sequentially shown in FIGS. Short focal length, intermediate focal length,
Aberration curve diagrams at the long focus end are sequentially shown in FIGS.

In each aberration curve diagram, the broken line in the figure of spherical aberration represents the sine condition. The solid line in the diagram of astigmatism represents sagittal and the broken line represents meridional. “Y ′” is the maximum image height, and the unit is “mm”. Also, the unit of the horizontal axis in the diagrams of spherical aberration, astigmatism, and distortion is “m
m ”. In each example, the short focal end, the intermediate focal length,
At the long focus end, the aberration is well corrected and the performance is good.

Of the above Examples 1-8, Examples 1-5
The second lens group II in the zoom lens of Embodiment 8 includes
In order from the object side, a first group I having a negative focal length, a second group II having a positive focal length, and a third group I having a positive focal length
II is disposed, and an aperture stop S that moves integrally with the second lens group II is provided on the object side of the second lens group, and the second lens group II is moved from the image side to the object side during zooming from the short focus end to the long focus end. Monotonically move to the first
In the zoom lens in which the group I moves so as to correct the variation of the image plane position due to the magnification change, it is a variable magnification group that is configured as the second group II and performs substantial magnification change. It consists of three lenses: a positive lens with a large curvature surface facing the object side, a negative lens with a large curvature surface facing the image side, and a positive lens. The most object-side surface and the most image-side surface are It is an aspherical surface (claim 1).

In the second lens group II of the zoom lenses of Examples 1 to 5 and Example 8, the thickness in the optical axis direction is L ₂ , the maximum image height is Y ′, and the condition is: (1) 1.0 < When (L ₂ /Y′)<2.5 is satisfied (Claim 2) and the radiuses of curvature of the object-side surface and the image-side surface of the most image-side positive lens are R ₃₁ and R ₃₂ , respectively, these There condition: (2) -0.4 <(R 31 + R 32) / (R 31 -R 32) satisfies <0.0 (claim 3).

Further, the second lens group I of the zoom lens of the first embodiment.
In I, it is a cemented lens in which a positive lens (fourth lens) closest to the object side and a negative lens (fifth lens) following it are cemented (claim 4), and Examples 2 to 5 and 8 In the second group II of the zoom lens, the three lenses are independent lenses (Claim 5).

The second lens group II of the zoom lenses of the sixth and seventh embodiments comprises, in order from the object side, a first lens group I having a negative focal length, a second lens group II having a positive focal length, and a positive focal length. The third lens group III which is held is disposed, and the diaphragm S that moves integrally with the second lens group is provided on the object side of the second lens group, and the second lens group II is moved toward the image side during zooming from the short focus end to the long focus end. In the zoom lens that moves monotonically from the object side to the object side, and the first lens group I moves so as to correct the fluctuation of the image plane position due to the zooming, the zoom lens is configured as the second lens group II to perform substantial zooming. In the double group, the most object-side surface and the most image-side surface are aspherical surfaces, and the thickness in the optical axis direction:
L ₂ and maximum image height: Y ′ satisfy the condition: (1) 1.0 <(L ₂ /Y′)<2.5 (claim 6), and the curvature of the object side increases in order from the object side. There are four lenses: a positive lens with a large surface (fourth lens), a negative lens with a large curvature surface toward the image side (fifth lens), a positive lens (sixth lens), and a positive lens (seventh lens). In Example 6, the positive lens (fourth lens) closest to the object side and the subsequent negative lens (fifth lens) are integrated as a cemented lens (Claim 8). )
ing. Therefore, in each zoom lens of Examples 1 to 8, in order from the object side, the first group I having a negative focal length, the second group II having a positive focal length, and the third group II having a positive focal length.
I is provided with an aperture stop S that moves integrally with the second lens unit on the object side of the second lens unit II, and when zooming from the short focal length end to the long focal length end, the second lens unit II moves from the image side. In a zoom lens that moves monotonically to the object side to perform substantial zooming, and the first lens group I moves so as to correct the change in image plane position due to zooming,
As the second group II, the variable power group according to any one of claims 1 to 8 is used (claim 9).

The zoom lenses of Examples 1 to 8 also have the first
The group I includes, in order from the object side, at least one negative lens having a large curvature surface facing the image side and at least one positive lens having a large curvature surface facing the object side. The most image-side surface of one negative lens is an aspherical surface (claim 10).

The zoom lenses of Examples 1 to 7 are the first group I.
, In order from the object side, a negative meniscus lens with a convex surface facing the object side (first lens), a negative lens with a large curvature surface facing the image side (second lens), and a large curvature surface facing the object side. And a positive lens (third lens), the image-side surface (fourth surface) of the negative lens with the surface having a large curvature facing the image side is an aspherical surface. 11), the focal length of the negative meniscus lens (first lens) arranged closest to the object in the first group I: f _L1 , the second negative lens (second lens) arranged from the object side of the first group I Focal length of f _L2
Conditions: (3) 0.7 <(f _L1 / f _L2 ) <2.0 is satisfied (claim 12).

The first group I of the zoom lens of the eighth embodiment includes, in order from the object side, a negative meniscus lens (first lens) having a convex surface facing the object side, and a positive lens (having a large curvature surface facing the object side). The image-side surface (second surface) of the negative meniscus lens is an aspherical surface (claim 13).

In each of the zoom lenses of Examples 1 to 8, the third lens is used.
Group III is composed of a positive lens with a surface having a large curvature facing the object side, and has at least one aspherical surface (object side surface).
(Claim 14), the zoom lens of each of Examples 1 to 8 has a total number of constituent lenses of 8 or less (7 in Examples 1 to 5, 8 in Examples 6 and 7). This is a single-sheet structure, which is a six-sheet structure in the eighth embodiment (claim 15).

FIG. 33 is a diagram for explaining one embodiment of the "camera device" of the present invention. 33A is a diagram showing the front side and the upper face, and FIG. 33C is a diagram showing the back side. The camera device 30 has, as the photographing lens 31, the zoom lens according to any one of claims 9 to 15 described above (appropriate one of Examples 1 to 8) as a "shooting zoom lens" (claim). Item 16).

In FIG. 33A, reference numeral 32 is a flash and reference numeral 33 is a finder. Zoom lever 34
The shutter button 35 and the shutter button 35 are arranged on the upper surface side of the main body. FIG. 33B is a diagram showing a usage state of the taking lens 31. The photographic lens 31 is shown in FIG.
As shown in FIG. 3 (a), the camera device is housed in a "collapsed type" (claim 17). In each of the above-described embodiments of the zoom lens, the number of lenses is as small as 6 to 8 and the thickness of the second group is small, so that the lens can be stored in a thin camera body by retracting.

As shown in FIG. 33 (c), the power switch 35, the operation button 37, and the liquid crystal monitor 38 are arranged on the rear side of the camera body, and the communication card slot 39A is provided.
The memory card slot 39B is arranged on the side surface of the main body.

FIG. 34 shows the "system structure" of the camera device.
FIG. The camera device 30 is a morphological information terminal device (claim 20). As shown in FIG. 34, the camera device has a taking lens 31 and a light receiving element (area sensor) 45, and is configured to read an image of an object to be photographed formed by the taking lens 31 with the light receiving element 45. The output from the element 45 is processed by the signal processing device 42 under the control of the central processing unit 40 and converted into digital information. That is, the camera device 30 has a "function of using a captured image as digital information" (claim 18).

The image information digitized by the signal processing device 42 is subjected to predetermined image processing in the image processing device 41 under the control of the central processing unit 40, and then the semiconductor memory 44 (set in the memory card slot 39B). Recorded). On the liquid crystal monitor 38, it is possible to display the image that is being photographed or the image recorded in the semiconductor memory 44. Further, the image recorded in the semiconductor memory 44 can be transmitted to the outside by using the communication card 43 or the like (set in the communication card slot 39A).

As shown in FIG. 33A, the taking lens 3
1 is in the “collapsed state” when the camera device 30 is carried,
When the user operates the power switch 36 to turn on the power,
The lens barrel is extended as shown in FIG. At this time, each group of zoom lenses in the lens barrel is, for example, “arrangement at the short focal end”, and the arrangement of each group is changed by operating the zoom lever 34 to change the magnification to the long focal end. It can be performed. At this time, the viewfinder 33 also changes its magnification in association with the change in the angle of view of the taking lens.

Focusing is performed by "half-pressing" the shutter button 35. Focusing can be performed by moving the first group or the third group, or moving the light receiving element. When the shutter button 35 is further pressed from the half-pressed state, shooting is performed, and thereafter, the above image information processing is executed.

When the image recorded in the semiconductor memory 44 is displayed on the liquid crystal monitor 38 or transmitted to the outside using the communication card 43 or the like, the operation button 37 is operated. If any one of Examples 1 to 8 is used as the taking lens 31, these have good performance. Therefore, a high-quality and compact camera using the 2 to 3 million pixel class light receiving element 45. An apparatus can be realized (claim 19).

[0087]

As described above, according to the present invention, it is possible to realize a novel zoom lens, zoom lens, and camera device. In the variable power group according to the present invention, the thickness in the optical axis direction is effectively reduced, so that the zoom lens can be made compact, and in particular, the retractable size of the retractable camera device can be effectively reduced.

Further, the zoom lens of the present invention can achieve further miniaturization as compared with the conventional one while maintaining the high performance required for digital image photographing, and the zoom lens of the present invention is used. The camera device is small and can be realized with high performance.

[Brief description of drawings]

FIG. 1 is a diagram showing a lens arrangement at a short focal end of a zoom lens of Embodiment 1 and a movement of each group due to zooming.

FIG. 2 is a diagram showing a lens arrangement at a short focal length end of a zoom lens of Embodiment 2 and movement of each group due to zooming.

FIG. 3 is a diagram showing a lens arrangement at a short focal length end of a zoom lens of Embodiment 3 and movement of each group due to zooming.

FIG. 4 is a diagram showing a lens arrangement at a short focal end of a zoom lens of Embodiment 4 and movement of each group due to zooming.

FIG. 5 is a diagram showing a lens arrangement at a short focal end of a zoom lens of Embodiment 5 and movement of each group due to zooming.

FIG. 6 is a diagram showing a lens arrangement at a short focal end of a zoom lens of Embodiment 6 and movement of each group due to zooming.

FIG. 7 is a diagram showing a lens arrangement at a short focal length end of a zoom lens of Embodiment 7 and movement of each group due to zooming.

FIG. 8 is a diagram showing a lens arrangement at a short focal length end of a zoom lens of Embodiment 8 and movement of each group due to zooming.

FIG. 9 is an aberration curve diagram at a short focal length end of the zoom lens of Example 1.

FIG. 10 is an aberration curve diagram at an intermediate focal length of the zoom lens of Example 1.

FIG. 11 is an aberration curve diagram at a long focal length end of the zoom lens of Example 1.

FIG. 12 is an aberration curve diagram for a zoom lens according to a second example at a short focal length end.

FIG. 13 is an aberration curve diagram at an intermediate focal length of the zoom lens of Example 2.

FIG. 14 is an aberration curve diagram at a long focal length end of the zoom lens of Example 2.

FIG. 15 is an aberration curve diagram at a short focal end of the zoom lens in Example 3;

FIG. 16 is an aberration curve diagram at an intermediate focal length of the zoom lens of Example 3.

FIG. 17 is an aberration curve diagram at a long focal length end of the zoom lens of Example 3.

FIG. 18 is an aberration curve diagram at a short focus end of the zoom lens in Example 4;

FIG. 19 is an aberration curve diagram at an intermediate focal length of the zoom lens of Example 4.

FIG. 20 is an aberration curve diagram at a long focal length end of the zoom lens of Example 4.

FIG. 21 is an aberration curve diagram for a zoom lens according to Example 5 at a short focal length end.

FIG. 22 is an aberration curve diagram at an intermediate focal length of the zoom lens of Example 5.

FIG. 23 is an aberration curve diagram at a long focal length end of the zoom lens in Example 5;

FIG. 24 is an aberration curve diagram at a short focal end of the zoom lens in Example 6;

FIG. 25 is an aberration curve diagram at an intermediate focal length of the zoom lens of Example 6.

FIG. 26 is an aberration curve diagram at a long focal length end of the zoom lens in Example 6;

FIG. 27 is an aberration curve diagram at a short focus end of the zoom lens in Example 7.

FIG. 28 is an aberration curve diagram at an intermediate focal length of the zoom lens of Example 7.

FIG. 29 is an aberration curve diagram at a long focal length end of the zoom lens in Example 7;

FIG. 30 is an aberration curve diagram at a short focal end of the zoom lens in Example 8.

FIG. 31 is an aberration curve diagram at an intermediate focal length of the zoom lens of Example 8.

FIG. 32 is an aberration curve diagram at a long focal length end of the zoom lens in Example 8;

FIG. 33 is a diagram for explaining the first embodiment of the camera device.

FIG. 34 is a diagram for explaining the system configuration of the embodiment of FIG. 33.

[Explanation of symbols]

I Group 1 II Second group III Group 3 S aperture

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H087 KA03 PA06 PA07 PA08 PA17                       PA18 PB06 PB07 PB08 QA02                       QA06 QA07 QA17 QA21 QA22                       QA25 QA32 QA34 QA41 QA45                       QA46 RA05 RA12 RA13 RA36                       RA42 RA43 SA14 SA16 SA19                       SA62 SA63 SA64 SB03 SB04                       SB14 SB15 SB22                 2H101 BB07 DD62                 5C022 AB66 AC54 AC78

Claims (20)

[Claims] 1. A first lens unit having a negative focal length in order from the object side.
Group, a second group having a positive focal length, and a third group having a positive focal length are arranged, and an aperture for moving integrally with the second group is provided on the object side of the second group, and it is long from the short focal end. In the zoom lens in which the second lens unit monotonously moves from the image side to the object side during zooming to the focal point, and the first lens group moves so as to correct the change in the image plane position due to zooming, Is a zoom lens group that performs substantial zooming in order from the object side, a positive lens with a large curvature surface facing the object side, a negative lens with a large curvature surface facing the image side, and a positive lens. A zooming group in a zoom lens, which is configured by arranging three lenses, and the surface closest to the object and the surface closest to the image are aspherical surfaces. 2. The variable power group according to claim 1, wherein the thickness in the optical axis direction is L ₂ , and the maximum image height is Y ′, the condition is: (1) 1.0 <(L ₂ / Y ′) <2 A zooming group in a zoom lens, characterized by satisfying the following condition. 3. In the variable power group according to claim 1 or 2, when the radiuses of curvature of the object side and image side surfaces of the most image side positive lens are R ₃₁ and R ₃₂ , respectively, these conditions are: _{(2) -0.4 <(R 31} + R 32) / (R 31 -R 32) <0.
A zooming group of a zoom lens, characterized by satisfying 0. 4. The zoom lens according to claim 1, 2 or 3, wherein the positive lens closest to the object side and a negative lens following the positive lens are cemented together. Variable magnification group. 5. A variable power group in a zoom lens according to claim 1, 2 or 3, wherein the three lenses are independent lenses. 6. A first lens unit having a negative focal length in order from the object side.
Group, a second group having a positive focal length, and a third group having a positive focal length are arranged, and an aperture for moving integrally with the second group is provided on the object side of the second group, and it is long from the short focal end. In the zoom lens in which the second lens unit monotonously moves from the image side to the object side during zooming to the focal point, and the first lens group moves so as to correct the change in the image plane position due to zooming, Is a zooming group configured to perform substantial zooming, in which the most object-side surface and the most image-side surface are aspherical surfaces, the thickness in the optical axis direction: L ₂ , and the maximum image height: Y ′ are Conditions: (1) A variable power group in a zoom lens, which satisfies 1.0 <(L ₂ /Y′)<2.5. 7. The variable power group according to claim 6, wherein in order from the object side, a positive lens having a large curvature surface facing the object side, a negative lens having a large curvature surface facing the image side, a positive lens, and a positive lens. A variable power group in a zoom lens, which is configured by arranging four lenses. 8. A variable power group in a zoom lens according to claim 6 or 7, wherein a positive lens closest to the object side and a negative lens following the positive lens are integrated as a cemented lens. . 9. A first lens unit having a negative focal length in order from the object side.
Group, a second group having a positive focal length, and a third group having a positive focal length are arranged, and an aperture for moving integrally with the second group is provided on the object side of the second group. The second lens group moves monotonically from the image side to the object side during zooming from the focal length to the long focal point, and performs substantial zooming, and the first lens group corrects the variation in the image plane position due to zooming. In the zoom lens that moves to, the zoom lens according to any one of claims 1 to 8 is used as the second lens group. 10. The zoom lens according to claim 9, wherein the first lens group has at least one negative lens having a surface having a large curvature facing the image side, and the surface having a large curvature facing the object side in order from the object side. A zoom lens characterized in that at least one positive lens is arranged, and the most image-side surface of the at least one negative lens is an aspherical surface. 11. The zoom lens according to claim 10, wherein the first group comprises, in order from the object side, a negative meniscus lens having a convex surface directed toward the object side, a negative lens having a surface having a large curvature directed toward the image side, and an object side. A three-lens configuration in which a positive lens having a surface having a large curvature is arranged on the image side, and the image side surface of the negative lens having a surface having a large curvature facing the image side is an aspherical surface. Zoom lens. 12. The zoom lens according to claim 11, wherein the focal length of the negative meniscus lens disposed closest to the object side of the first lens group is f _L1 , and the negative lens disposed second from the object side of the first lens group. The zoom lens is characterized in that the focal length: f _L2 satisfies the condition: (3) 0.7 <(f _L1 / f _L2 ) <2.0. 13. The zoom lens according to claim 10, wherein the first group comprises, in order from the object side, a negative meniscus lens having a convex surface directed toward the object side and a positive lens having a surface having a large curvature directed toward the object side. A zoom lens having a double-lens structure, wherein the image-side surface of the negative meniscus lens is an aspherical surface. 14. The zoom lens according to any one of claims 9 to 13, wherein the third lens unit is composed of a positive lens having a surface having a large curvature facing the object side, and has at least one aspherical surface. This is a zoom lens. 15. The zoom lens according to claim 9, wherein the total number of constituent lenses is 8 or less. 16. A camera device having the zoom lens according to any one of claims 9 to 15 as a zoom lens for photographing. 17. The camera device according to claim 16, wherein the photographing zoom lens is retractably housed. 18. The camera device according to claim 16 or 17, wherein the camera device has a function of converting a captured image into digital information. 19. The camera device according to claim 18, wherein the light receiving element for receiving an image by the zoom lens has 2 million pixels or more. 20. The camera device according to claim 18, which is a portable information terminal device.