JP4722425B2 - Electronic imaging device - Google Patents

Description

  The present invention relates to an electronic imaging device, and more particularly, to a zoom lens whose depth is extremely thin when stored and an electronic imaging device having the same.

  In recent years, digital cameras (electronic cameras) have attracted attention as next-generation cameras that replace silver salt 35 mm film (commonly known as Leica version) cameras. Furthermore, it has come to have a number of categories in a wide range from high-functional types for business use to portable popular types. The present invention pays attention to the category of portable popular types in particular, and aims to provide a technology for realizing a video camera and a digital camera with a thin depth while ensuring high image quality.

The greatest bottleneck in reducing the depth direction of the camera is the thickness from the most object-side surface to the imaging surface of the optical system, particularly the zoom lens system. Recently, it has become a mainstream to employ a so-called collapsible lens barrel that projects an optical system from the camera body during shooting and stores the optical system in the camera body when carried. As such conventional examples, there are those disclosed in Patent Documents 1 to 4.
Japanese Patent Laid-Open No. 11-258507 JP 11-52246 A JP 9-33810 A JP-A-11-142734

  However, the thickness when the optical system is retracted varies greatly depending on the lens type and filter used. In particular, when considering setting high specifications such as a zoom ratio and F value, a so-called positive leading zoom lens in which the lens unit closest to the object side has a positive refractive power has a thickness and dead space of each lens element. However, even when retracted, the thickness does not decrease much (Patent Document 1). The negative leading type, especially the zoom lens having 2 to 3 groups, is advantageous in this respect, but it is retracted even when the number of elements in the group is large, the thickness of the element is large, or the most object side lens is a positive lens. (Patent Document 2).

  As an example of what is currently known, it is suitable for an electronic imaging device and has good imaging performance including zoom ratio, angle of view, F number, etc. Document 3 and Patent Document 4 are available.

  In the optical system in the above-mentioned patent document, when the entrance pupil position of the first lens group is made shallower, the diameter becomes smaller, and as a result, the first lens group itself can be made thinner. However, for this purpose, the magnification of the second lens group must be increased, that is, the refractive power must be increased. Therefore, there is no choice but to sacrifice imaging performance or sacrifice the depth by increasing the number of components.

  The present invention has been made in view of the above-described problems of the prior art, and its purpose is to form an image in the entire zooming range with a very small thickness in the depth direction when the lens is retracted (when retracted). It is an object of the present invention to provide a zoom lens having a highly stable performance and an electronic imaging apparatus having the same.

The electronic imaging device of the present invention that achieves the above object is a zoom lens comprising, in order from the object side, a first lens group G1 having a negative refractive power, an aperture stop, and a second lens group having a positive refractive power. And an electronic image sensor located on the image side of the zoom lens,
The distance between the lens groups of the first lens group G1 and the second lens group G2 is variable at the time of zooming or focusing, and the first lens group G1 has two components, a negative lens component having an aspheric surface and a positive lens component. An electronic image pickup device capable of processing image data obtained by picking up an image formed through the zoom lens with the electronic image pickup device and outputting the processed image data as image data having a changed shape There,
The zoom lens satisfies the following conditions.
(1) 0.7 <y ₀₈ ^* / (f _W · tan ω _08W ) <0.96
(4) "'0.3<d1 / y 10 * ≦ 0.44128
However, if the distance (maximum image height) from the center to the farthest point in the effective imaging plane (in the imaging-capable plane) of the electronic imaging device is y ₁₀ ^* , y ₀₈ ^* = 0.8 y ₁₀ ^* , ω _08W is an angle with respect to the optical axis in the object direction corresponding to the image point connected to the position of y ₀₈ ^* from the center on the imaging surface at the wide angle end, and y ₁₀ ^* is 0 <y ₁₀ ^* <6 (mm) D1 is an air interval on the optical axis of the negative lens component and the positive lens component of the first lens group G1, and the lens component is a thin lens having a thickness of less than 1 mm made of a resin or the like on the lens surface or the lens surface. It means a compound lens in which the lens is closely cured.

In this case, it is desirable to satisfy the following conditions.
(2) 1.2 <y ₁₀ ^* / a <6.0
Where y ₁₀ ^* is the distance (maximum image height) from the center to the farthest point in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging device, the unit is mm, and a is the long side of the electronic imaging device The distance between pixels in the direction, the unit is μm.
In addition, it is desirable that the negative lens component of the first lens group G1 satisfies both the shape factor and the medium refractive index satisfying the following conditions.
(6) 0.0 <(R _11F + R _11R ) / (R _11F −R _11R ) <1.5
(7) 1.55 <n1
Where R _11F and R _11R are the radiuses of curvature on the optical axis of the most object side surface and the most image side surface of the negative lens component of the most object side lens group G1, respectively, and n1 is the center of the negative lens component. It is the refractive index of a thick lens element.
Further, it is desirable that the thickness t1 on the optical axis from the most object side surface to the most image side surface of the first lens group G1 satisfies the following condition.
(8) 0.7 <t1 / y 10 * <1.35
However, the distance (maximum image height) y ₁₀ ^* from the center to the farthest point from the center in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging element is 0 <y ₁₀ ^* <6 (mm).
In addition, it is desirable that the second lens group G2 always moves toward the object side when zooming from the wide-angle side toward the telephoto side, and satisfies the following conditions.
(10) 0.7 <t2 / y10 * <1.6
Here, t2 is the distance on the optical axis from the most object-side surface to the most image-side surface of the second lens group G2. Here, the distance (maximum image height) y10 * from the center to the farthest point in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging device is 0 <y10 * <6 (mm).

Another electronic imaging device of the present invention that achieves the above object includes, in order from the object side, a first lens group G1 having negative refractive power, an aperture stop, and a second lens group having positive refractive power. A zoom lens and an electronic image sensor located on the image side of the zoom lens,
The distance between the lens groups of the first lens group G1 and the second lens group G2 is variable at the time of zooming or focusing, and the first lens group G1 has two components: a negative lens component having an aspheric surface and a positive lens component. An electronic imaging apparatus capable of processing image data obtained by imaging an image formed through the zoom lens with the electronic imaging device and outputting the processed image data as image data having a changed shape There,
The zoom lens satisfies the following conditions.
(1) 0.7 <y ₀₈ ^* / (f _W · tan ω _08W ) <0.96
(6) "'0.0 <( _R11F + _R11R ) / ( _{R11F- R11R} ) <0.9
(7) 1.55 <n1
However, if the distance (maximum image height) from the center to the farthest point in the effective imaging plane (in the imaging-capable plane) of the electronic imaging device is y ₁₀ ^* , y ₀₈ ^* = 0.8 y ₁₀ ^* , ω _08W is an angle with respect to the optical axis in the object direction corresponding to the image point connected to the position of y ₀₈ ^* from the center on the imaging surface at the wide angle end, and y ₁₀ ^* is 0 <y ₁₀ ^* <6 (mm) R _11F and R _11R are the radii of curvature on the optical axis of the most object side surface and the most image side surface of the negative lens component of the most object side lens group G1, respectively, and n1 is the negative lens component. The lens component means a compound lens in which a single lens or a thin lens made of resin or the like and having a thickness of less than 1 mm is adhered and cured to the lens surface.

  Below, the reason and effect | action which take the said structure in this invention are demonstrated.

  In the first lens group closest to the object side, the diameter tends to be the largest. Therefore, a large barrel distortion is intentionally generated at the focal length near the wide-angle end of the zoom lens, and an image is formed on the electronic image pickup device in this state. In this way, the effective diameter of the lens group G1 closest to the object can be reduced. As a result, the zoom lens itself can be thinned. Furthermore, it is assumed that the lens group G1 includes only two components, a negative lens component and a positive lens component. In this case, in order to correct distortion, the distance between the two lens components must be greater than a certain value. However, by allowing the amount of distortion, this distance becomes unnecessary. Therefore, by doing in this way, it can contribute also to thickness reduction here. By the way, an image distorted in a barrel shape is photoelectrically converted by an image sensor and obtained as image data. This electronic data is electrically processed in the signal processing system of the electronic imaging device. This process is a process corresponding to a shape change. By such processing, image data that is finally output from the electronic imaging device can be obtained. When this image data is reproduced on some display device, the distortion is corrected. That is, an image substantially similar to the subject shape is obtained.

  In this way, the purpose of introducing distortion correction intentionally in an optical system and correcting the distortion by electrically processing the image after imaging with an electronic image sensor is to reduce the size of the optical system or increase the angle (distortion). The vertical angle of view is 38 ° or more).

If there is no distortion in the image obtained by imaging an infinite object,
f = y ^* / tan ω = y / tan ω
Is established. Where y ^* is the height of the image point from the optical axis, y is the height of the ideal image point (image point when the optical system has no distortion) from the optical axis, f is the focal length of the imaging system, ω is an angle with respect to the optical axis in the object direction corresponding to the image point connected from the center on the imaging surface to the position of y ^* .

If the imaging system has barrel distortion,
f> y ^* / tanω
It becomes. That is, if f and y are constant, ω is a large value.

  Condition (1) defines the degree of barrel distortion at the zoom wide-angle end. If the upper limit of 0.96 is exceeded, it will be difficult to reduce the size and thickness. If the lower limit of 0.7 is not reached, when image distortion due to distortion of the optical system is corrected by image processing, the stretching ratio in the radial direction of the peripheral portion of the field angle becomes too high. As a result, the sharpness degradation at the periphery of the image becomes noticeable.

  Moreover, it is more preferable to satisfy the following.

(1) ′ 0.75 <y ₀₈ ^* / (f _W · tan ω _08W ) <0.94
Furthermore, it is most preferable to satisfy the following.

(1) ”0.80 <y ₀₈ ^* / (f _W · tan ω _08W ) <0.92
By the way, the actual image height y ^* is a function of the ideal image height y. Here, in the local y where the differential value dy ^* / dy becomes larger than a certain level, the local enlargement ratio at the time of distortion correction becomes too large. Therefore, it becomes difficult to obtain a predetermined resolving power at that portion. Therefore, it is more preferable to satisfy the following.

(1-2) 0.4 <(dy ^* / dy) _{y08 *} / (dy ^* / dy) _{y00 *} <0.9
_{^{However, (dy * / dy) y08}} * is, dy in the _{^{y 08 * = 0.8y 10 * *}} / dy, (dy * / dy) y00 * is dy in _{^{y 00 * = 0.0y 10 * *}} / dy It is.

  If the lower limit of 0.4 of the condition (1-2) is not reached, the local enlargement ratio at the time of distortion correction becomes too large, and it becomes difficult to obtain a predetermined resolving power at that portion. When the upper limit of 0.9 is exceeded, it becomes difficult to achieve the object of the present invention.

  Moreover, it is more preferable to satisfy the following.

(1-2) '0.5 <(dy ^* / dy) _{y08 *} / (dy ^* / dy) _{y00 *} <0.85
Furthermore, it is most preferable to satisfy at least the following.

(1-2) "0.55 <(dy ^* / dy) _{y08 *} / (dy ^* / dy) _{y00 *} <0.8
Note that the image forming ability of the zoom lens corresponds to an electronic imaging apparatus that satisfies the following condition (2).

(2) 1.2 <y ₁₀ ^* / a <6.0
Where y ₁₀ ^* is the distance (maximum image height) from the center to the farthest point in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging device, the unit is mm, and a is the long side of the electronic imaging device The distance between pixels in the direction, the unit is μm.

  In order to make the zoom lens thin, it is desirable not to use an optical low-pass filter as much as possible. Therefore, the following condition (3) should be satisfied.

(3) F _W ≧ 1.1a (μm)
Here, _FW is the release F value at the wide-angle end, a is the distance between pixels in the long side direction of the electronic image sensor, and the unit is μm.

  This utilizes the fact that when the pixel size is reduced to some extent, the component above the Nyquist frequency disappears due to the influence of diffraction. If the condition (3) is not satisfied, an optical low-pass filter is required.

  If this condition is satisfied, aliasing distortion can be tolerated without an optical low-pass filter. In order to ensure image quality, it is better that the aperture stop is only open and not narrowed down. Then, it becomes possible to reduce the size and thickness by the amount that can eliminate the narrowing mechanism.

  Further, it is more preferable to satisfy the condition (3) ′.

(3) 'F _W ≧ 1.2a (μm)
Further, the condition (3) "is most preferable.

(3) “F _W ≧ 1.3a (μm)
As described above, it is preferable to configure the zoom lens of the electronic imaging apparatus while allowing distortion to some extent. The air distance d1 on the optical axis of the negative lens component and the positive lens component of the lens group G1 closest to the object side should satisfy the following condition (4).

(4) 0.3 <d1 / y 10 * <0.6
However, the distance (maximum image height) y ₁₀ ^* from the center to the farthest point from the center in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging element is 0 <y ₁₀ ^* <6 (mm).

  If d1 is reduced for thinning, the optimum principal point position of the lens group G1 shifts to the image side. Therefore, when trying to return it, the curvature of the surface closest to the object side of the negative lens component moves in the negative direction (for example, a meniscus shape convex toward the image side). As a result, distortion or astigmatism worsens. In view of this, the distortion is corrected to the barrel shape by image processing. However, if d1 is reduced to be less than the lower limit of 0.3, the distortion when the astigmatism is corrected becomes too large. In this case, it is difficult to ensure the resolution at the periphery of the screen even if correction is performed by image processing. When the upper limit of 0.6 is exceeded, it is difficult to make the entire lens system thinner as in the prior art.

  Further, it is more preferable that the condition (4) ′ is satisfied.

(4) '0.33 <d1 / y 10 * <0.55
Further, it is most preferable that the condition (4) "is satisfied.

(4) "0.36 <d1 / y 10 * <0.5
Alternatively, the negative lens component and the positive lens component of the lens group G1 closest to the object may satisfy the following condition (5). This makes it easy to reduce d1.

(5) 0.55 <R _11R / R _12F <0.95
However, R _11R is the most image side surface of the negative lens component of the lens unit G1 closest to the object side, and R _12F is the curvature of the most object side surface of the positive lens component of the lens unit G1 closest to the object side on the optical axis. Radius.

  In this case, if the upper limit of 0.95 of the condition (5) is exceeded, the distortion when the astigmatism is corrected becomes too large, and the resolution of the peripheral portion of the screen is ensured even if it is corrected by image processing. It becomes difficult. If the lower limit of 0.55 is not reached, it is difficult to make the entire lens system thinner as in the prior art.

  Further, it is more preferable that the condition (5) ′ is satisfied.

(5) '0.6 <R _11R / R _12F <0.9
Further, it is most preferable that the condition (5) "is satisfied.

(5) ”0.65 <R _11R / R _12F <0.85
From another viewpoint, it is preferable that the negative lens component of the lens group G1 closest to the object side satisfies both of the following conditions (6) and (7) in terms of the shape factor and the medium refractive index.

(6) 0.0 <(R _11F + R _11R ) / (R _11F −R _11R ) <1.5
(7) 1.55 <n1
Where R _11F and R _11R are the radiuses of curvature on the optical axis of the most object side surface and the most image side surface of the negative lens component of the most object side lens group G1, respectively, and n1 is the center of the negative lens component. It is the refractive index of a thick lens element.

  When the lower limit value of 0.0 in the condition (6) is not reached, distortion when the astigmatism is corrected becomes too large. In this case, it is difficult to ensure the resolution at the periphery of the screen even if correction is performed by image processing. When the upper limit of 1.5 is exceeded, it is difficult to make the entire lens system thinner as in the prior art. Note that if the refractive index of the lens element with the thickest central thickness of the negative lens component of the lens group G1 satisfies the condition (7) and does not exceed a certain value, the desired resolution can be secured even if the condition (6) is satisfied. It becomes difficult.

  Further, it is more preferable that the conditions (6) ′ and (7) ′ are satisfied.

(6) ′ 0.3 <(R _11F + R _11R ) / (R _11F −R _11R ) <1.2
(7) '1.60 <n1
Further, it is most preferable that the conditions (6) "and (7)" are satisfied.

(6) ”0.5 <(R _11F + R _11R ) / (R _11F −R _11R ) <0.9
(7) "1.65 <n1
Alternatively, the thickness t1 on the optical axis from the most object-side surface of the most object-side lens group G1 to the most image-side surface may satisfy the following condition.

(8) 0.7 <t1 / y 10 * <1.35
However, the distance (maximum image height) y ₁₀ ^* from the center to the farthest point from the center in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging element is 0 <y ₁₀ ^* <6 (mm).

  If t1 is made smaller than the lower limit 0.7 of condition (8), the distortion aberration when correcting astigmatism becomes too large. In this case, it is difficult to ensure the resolution at the periphery of the screen even if correction is performed by image processing. When the upper limit of 1.35 is exceeded, it is difficult to make the entire lens system thinner as in the prior art.

  Further, it is more preferable that the condition (8) ′ is satisfied.

(8) '0.8 <t1 / y 10 * <1.3
Further, it is most preferable that the condition (8) "is satisfied.

(8) "0.85 <t1 / y 10 * <1.25
Note that the most object-side lens group G1 described above may be composed of only two lens elements, a negative lens and a positive lens, in order from the object side.

  Now, the lens group G2 adjacent to the image side of the lens group G1 closest to the object side always moves toward the object side when zooming from the wide angle side toward the telephoto side. The following condition (9) is satisfied.

(9) 1.3 <−β _T <2.1
Where β _T is the lateral magnification of the lens group G2 at the telephoto end. Here, the distance (maximum image height) y ₁₀ ^* from the center to the farthest point from the center in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging device is 0 <y ₁₀ ^* <6 (mm). .

  In order to reduce the size and thickness of the lens group G1, it is effective to reduce its effective diameter. For this purpose, the lateral magnification of the lens group G2 is important. If the lower limit of 1.3 of condition (9) is not reached, the total length at the wide-angle end becomes longer. Therefore, the mechanism for collapsing becomes complicated and large. In addition, the effective diameter of the lens group G1 is enlarged, which tends to be an obstacle to thinning. If the upper limit of 2.1 is exceeded, it is difficult to ensure a desired resolution unless the number of components of the second lens group G2 is increased.

  Further, it is more preferable that the condition (9) ′ is satisfied.

(9) ′ 1.35 <−β _T <2.0
Further, it is most preferable that the condition (9) "is satisfied.

(9) ”1.4 <−β _T <1.9
The lens group G2 adjacent to the image side of the lens group G1 closest to the object side always moves toward the object side when zooming from the wide-angle side to the telephoto side, and satisfies the following conditions.

(10) 0.7 <t2 / y 10 * <1.6
Here, t2 is the distance on the optical axis from the most object side surface of the lens group G2 to the most image side surface. Here, the distance (maximum image height) y ₁₀ ^* from the center to the farthest point from the center in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging device is 0 <y ₁₀ ^* <6 (mm). .

  If the lower limit of 0.7 of condition (10) is not reached, it will be difficult to correct astigmatism over the entire zoom range. On the other hand, if the upper limit of 1.6 is exceeded, there is no point in reducing the number of lenses in the lens group G2 by using many aspheric surfaces.

  Further, it is more preferable that the condition (10) ′ is satisfied.

(10) ′ 0.8 <t 2 / y ₁₀ ^* <1.5
Furthermore, it is most preferable that the condition (10) "is satisfied.

(10) "0.9 <t2 / y 10 * <1.4
In addition, it is preferable that the following conditions are satisfied with respect to how to move the lens group G2. This is good for thinning when retracted.

(11) 0.10 <D _12T / y ₁₀ ^* <0.7
Here, D _12T is the distance on the optical axis from the most image-side surface of the lens group G1 to the most object-side surface of the lens group G2 at the telephoto end and when focusing on an object point at infinity. Here, the distance (maximum image height) y ₁₀ ^* from the center to the farthest point from the center in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging device is 0 <y ₁₀ ^* <6 (mm). .

  If the upper limit of 0.7 of condition (11) is exceeded, the size of the optical system tends to increase. That is, the whole becomes thick and is contrary to the object of the invention. If the lower limit of 0.10 is not reached, the total thickness of the lens portion at the telephoto end can be reduced, so that it is easy to reduce the thickness when retracted. However, mechanical interference of the lens group tends to occur during zooming.

The aperture stop is adjacent to the object side of the lens group G2 and moves integrally with the lens group G2. Therefore, if D _12T is reduced, it becomes an obstacle. However, the most object-side surface of the lens group G2 is a convex surface on the object side. Therefore, if the aperture stop is arranged so that the lens surface penetrates the inner diameter portion of the aperture stop, the obstacle is eliminated.

  In the electronic image pickup apparatus of the present invention, since the pixel pitch is small, the diaphragm is not narrowed down in consideration of deterioration due to diffraction. In other words, the following conditions should be satisfied.

(12) -0.7 <ds / y 10 * <0
Here, ds is the distance between the intersection position of the surface including the aperture part (inner diameter part) of the aperture stop that determines the light beam on the outermost axis and the optical axis, and the top of the lens group G2 closest to the object side, and the negative value is This is a case where the latter is on the object side of the former.

  Condition (12) is set to make it easier to satisfy condition (11). Exceeding the upper limit of 0 makes it difficult to satisfy the condition (11), and even if the value falls below the lower limit of −0.7, the effect for satisfying the condition (11) does not increase and is meaningless.

  Further, it is more preferable that the conditions (11) ′ and (12) ′ are satisfied.

(11) ′ 0.15 <D _12T / y ₁₀ ^* <0.6
(12) ′ −0.6 <ds / y ₁₀ ^* <− 0.05
Furthermore, it is most preferable that the conditions (11) "and (12)" are satisfied.

(11) ”0.20 <D _12T / y ₁₀ ^* <0.5
(12) "-0.5 <ds / y 10 * <-0.1
As described above, the lens group closest to the object tends to be large. One of the major factors that determine the size of the lens group G1 is the position of the aperture stop as viewed from the most object side surface of the lens group G1. Although the aperture stop is located on the image side of the lens group G1, it is preferable to satisfy the following conditions.

(13) 4.0 <P _W / y ₁₀ ^* <6.5
Here, P _W is the distance on the optical axis from the most object-side surface to the aperture stop position at the wide-angle end. Here, the distance (maximum image height) y ₁₀ ^* from the center to the farthest point from the center in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging device is 0 <y ₁₀ ^* <6 (mm). .

  If the lower limit of 4.0 of the condition (13) is not reached, it is good for downsizing the lens group G1, but the burden (refractive power) of the lens group G2 increases, and the imaging performance is likely to deteriorate. If the upper limit of 6.5 is exceeded, the lens group tends to be large.

  Further, it is more preferable that the condition (13) ′ is satisfied.

(13) '4.2 <P _W / y ₁₀ ^* <6.0
Furthermore, it is most preferable that the condition (13) "is satisfied.

(13) "4.4 <P _W / y ₁₀ ^* <5.5
The lens group G2 adjacent to the image side of the lens group G1 closest to the object side can be composed of only two components, a positive lens component and a negative lens component, in order from the object side. Further, it can be configured with only two lens elements, a positive lens and a negative lens. In this case, it is preferable to satisfy the condition (14) regarding the negative lens component or the shape of the negative lens.

(14) -10 <( _R22F + _R22R ) / ( _{R22F- R22R} ) <0.5
Here, R _22F and R _22R are the radii of curvature on the optical axis of the most object side surface and the most image side surface in the negative lens component of the lens group G2, respectively.

  If the upper limit of 0.5 of the condition (14) is exceeded, the lens movement amount when retracted tends to be reduced, but coma aberration and the like are likely to deteriorate. Below the lower limit of −10, the amount of lens movement when retracted tends to increase.

  It is more preferable that the condition (14) ′ is satisfied.

(14) ′ − 8 <(R _22F + R _22R ) / (R _22F −R _22R ) <− 0.5
Further, it is most preferable that the condition (14) "is satisfied.

(14) "-6 <( _R22F + _R22R ) / ( _{R22F- R22R} ) < _-2
Regarding the above conditions (1) to (14), any two or more of them or any combination of lower conditions may be satisfied.

  According to the present invention, in order to make the thickness in the depth direction very thin when retracting the lens (when retracted), the imaging performance is extremely stable and high in all zooming ranges even if the total number of lenses is set to a minimum of four. An electronic imaging device equipped with a zoom lens can be obtained.

  Embodiments 1 to 4 of the zoom lens used in the electronic imaging apparatus of the present invention will be described below. Lens cross-sectional views of the wide-angle end (a), the intermediate state (b), and the telephoto end (c) when focusing on an object point at infinity in Examples 1 to 4 are shown in FIGS. In the figure, the first lens group is G1, the aperture stop is S, the second lens group is G2, the parallel plate constituting the low-pass filter with IR cut coat, etc. is L, and the parallel plate of the cover glass of the electronic image sensor is G. The image plane is indicated by I. In addition, a multilayer film for limiting the wavelength band may be applied to the surface of the cover glass G. Further, the cover glass G may have a low-pass filter function.

  As shown in FIG. 1, the zoom optical system according to the first exemplary embodiment includes, in order from the object side, a first lens group G1 having a negative refractive power, an aperture stop S, and a second lens group G2 having a positive refractive power. When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves along a locus convex toward the image side, and is located closer to the image side than the wide-angle end position at the telephoto end. The aperture stop S and the second lens group G2 move monotonously toward the object side while integrally reducing the distance between the first lens group G1.

  In order from the object side, the first lens group G1 includes a biconcave negative lens and a positive meniscus lens having a convex surface facing the object side, and the second lens group G2 has a biconvex positive lens and a convex surface facing the image side. It consists of a negative meniscus lens.

  Aspherical surfaces are used for eight of all lens surfaces.

  As shown in FIG. 2, the zoom optical system of Example 2 includes, in order from the object side, a first lens group G1 having a negative refractive power, an aperture stop S, and a second lens group G2 having a positive refractive power. When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves along a locus convex toward the image side, and is located closer to the image side than the wide-angle end position at the telephoto end. The aperture stop S and the second lens group G2 move monotonously toward the object side while integrally reducing the distance between the first lens group G1.

  In order from the object side, the first lens group G1 includes a biconcave negative lens and a positive meniscus lens having a convex surface facing the object side, and the second lens group G2 has a biconvex positive lens and a convex surface facing the image side. It consists of a negative meniscus lens.

  Aspherical surfaces are used for eight of all lens surfaces.

  As shown in FIG. 3, the zoom optical system according to the third exemplary embodiment includes, in order from the object side, a first lens group G1 having a negative refractive power, an aperture stop S, and a second lens group G2 having a positive refractive power. When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves along a locus convex toward the image side, and is located closer to the image side than the wide-angle end position at the telephoto end. The aperture stop S and the second lens group G2 move monotonously toward the object side while integrally reducing the distance between the first lens group G1.

  In order from the object side, the first lens group G1 includes a biconcave negative lens and a positive meniscus lens having a convex surface facing the object side, and the second lens group G2 has a biconvex positive lens and a convex surface facing the image side. It consists of a negative meniscus lens.

  Aspherical surfaces are used for eight of all lens surfaces.

  As shown in FIG. 4, the zoom optical system according to the fourth exemplary embodiment includes, in order from the object side, a first lens group G1 having a negative refractive power, an aperture stop S, and a second lens group G2 having a positive refractive power. When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves along a locus convex toward the image side, and is located closer to the image side than the wide-angle end position at the telephoto end. The aperture stop S and the second lens group G2 move monotonously toward the object side while integrally reducing the distance between the first lens group G1.

  In order from the object side, the first lens group G1 includes 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 G2 includes a biconvex positive lens, It consists of a biconcave negative lens.

  The aspheric surfaces are used for the six surfaces of the image side surface of the negative meniscus lens of the first lens group G1, the object side surface of the positive meniscus lens, and all the lens surfaces of the second lens group G2.

In the following, the numerical data of each of the above embodiments is shown. Symbols are the above, f is the total focal length, _FNO is the F number, WE is the wide angle end, ST is the intermediate state, TE is the telephoto end, r ₁ , R ₂ ... Are the radii of curvature of the lens surfaces, d ₁ , d ₂ ... _Are the distances between the lens surfaces, n _d1 , n _d2 are the refractive indices of the d-line of each lens, and ν _d1 , ν _d2 . It is the Abbe number of the lens. The aspherical shape is represented by the following formula, where x is an optical axis with the light traveling direction being positive, and y is a direction orthogonal to the optical axis.

x = (y ² / r) / [1+ {1- (K + 1) (y / r) ² } ^1/2 ]
+ A ₄ y ⁴ + A ₆ y ⁶ + A ₈ y ⁸
Here, r is a paraxial radius of curvature, K is a conical coefficient, and A ₄ , A ₆ , and A ₈ are fourth-order, sixth-order, and eighth-order aspheric coefficients, respectively.

Example 1
r ₁ = -80.3012 (aspherical surface) d ₁ = 1.0000 n _d1 = 1.74320 ν _d1 = 49.34
r ₂ = 6.1213 (aspherical surface) d ₂ = 1.5886
r ₃ = 7.8091 (aspherical surface) d ₃ = 1.6298 n _d2 = 1.84666 ν _d2 = 23.78
r ₄ = 12.6372 (aspherical surface) d ₄ = (variable)
r ₅ = ∞ (aperture) d ₅ = -0.5000
r ₆ = 4.5177 (aspherical surface) d ₆ = 2.1059 n _d3 = 1.58913 ν _d3 = 61.14
r ₇ = -11.6839 (aspherical surface) d ₇ = 0.5364
r ₈ = -4.0191 (aspherical surface) d ₈ = 1.0393 n _d4 = 1.84666 ν _d4 = 23.78
r ₉ = -6.9703 (aspherical surface) d ₉ = (variable)
r ₁₀ = ∞ d ₁₀ = 0.9600 n _d5 = 1.54771 ν _d5 = 62.84
r ₁₁ = ∞ d ₁₁ = 0.6000
r ₁₂ = ∞ d ₁₂ = 0.5000 n _d6 = 1.51633 ν _d6 = 64.14
r ₁₃ = ∞ d ₁₃ = 0.5000
r ₁₄ = ∞ (image plane)
Aspheric coefficient 1st surface K = 0
A ₄ = 9.0166 × 10 ^-5
A ₆ = 0.0000
Second side K = 0
A ₄ = -4.1100 × 10 ^-4
A ₆ = 2.6370 × 10 ^-5
Third side K = 0
A ₄ = -7.3294 × 10 ^-4
A ₆ = 2.6541 × 10 ^-5
4th surface K = 0
A ₄ = -5.6865 × 10 ^-4
A ₆ = 1.6975 × 10 ^-5
6th surface K = 0
A ₄ = 5.0962 × 10 ^-4
A ₆ = 0.0000
Surface 7 K = 0
A ₄ = 3.6845 × 10 ^-3
A ₆ = 0.0000
8th surface K = 0
A ₄ = 1.3837 × 10 ^-2
A ₆ = -2.1725 × 10 ^-4
9th surface K = 0
A ₄ = 9.2372 × 10 ^-3
A ₆ = 1.5395 × 10 ^-4
Zoom data (∞)
WE ST TE
f (mm) 6.00611 11.99361 17.91963
F _NO 3.1351 4.3092 5.5123
d ₄ 14.5657 4.8297 1.6000
d ₉ 9.3815 13.9712 18.5540.

Example 2
r ₁ = -48.0000 (aspherical surface) d ₁ = 1.0000 n _d1 = 1.74320 ν _d1 = 49.34
r ₂ = 5.6908 (aspherical surface) d ₂ = 1.4977
r ₃ = 7.4496 (aspherical surface) d ₃ = 1.5669 n _d2 = 1.84666 ν _d2 = 23.78
r ₄ = 12.8049 (aspherical surface) d ₄ = (variable)
r ₅ = ∞ (aperture) d ₅ = -0.5000
r ₆ = 4.7641 (aspherical surface) d ₆ = 2.3639 n _d3 = 1.49700 ν _d3 = 81.54
r ₇ = -7.9339 (aspherical surface) d ₇ = 0.8763
r ₈ = -4.2374 (aspherical surface) d ₈ = 1.0952 n _d4 = 1.84666 ν _d4 = 23.78
r ₉ = -6.5441 (aspherical surface) d ₉ = (variable)
r ₁₀ = ∞ d ₁₀ = 0.9600 n _d5 = 1.54771 ν _d5 = 62.84
r ₁₁ = ∞ d ₁₁ = 0.6000
r ₁₂ = ∞ d ₁₂ = 0.5000 n _d6 = 1.51633 ν _d6 = 64.14
r ₁₃ = ∞ d ₁₃ = 0.5000
r ₁₄ = ∞ (image plane)
Aspheric coefficient 1st surface K = 0
A ₄ = 1.4590 × 10 ^-4
A ₆ = 0.0000
Second side K = 0
A ₄ = -6.5163 × 10 ^-4
A ₆ = 4.4567 × 10 ^-5
Third side K = 0
A ₄ = -8.9735 × 10 ^-4
A ₆ = 4.6463 × 10 ^-5
4th surface K = 0
A ₄ = -6.1437 × 10 ^-4
A ₆ = 3.0689 × 10 ^-5
6th surface K = 0
A ₄ = -2.0881 × 10 ^-4
A ₆ = 0.0000
Surface 7 K = 0
A ₄ = 3.7741 × 10 ^-3
A ₆ = 0.0000
8th surface K = 0
A ₄ = 1.1838 × 10 ^-2
A ₆ = -1.4228 × 10 ^-4
9th surface K = 0
A ₄ = 7.3941 × 10 ^-3
A ₆ = 1.0081 × 10 ^-4
Zoom data (∞)
WE ST TE
f (mm) 6.00423 11.99020 17.93935
F _NO 3.0434 4.1365 5.2256
d ₄ 13.2974 4.5198 1.6000
d ₉ 9.4288 14.4655 19.5101.

Example 3
r ₁ = -33.6563 (aspherical surface) d ₁ = 1.0000 n _d1 = 1.74320 ν _d1 = 49.34
r ₂ = 6.2347 (aspherical surface) d ₂ = 1.4796
r ₃ = 8.8272 (aspherical surface) d ₃ = 1.6011 n _d2 = 1.82114 ν _d2 = 24.06
r ₄ = 18.7944 (aspherical surface) d ₄ = (variable)
r ₅ = ∞ (aperture) d ₅ = -0.5000
r ₆ = 4.6767 (aspherical surface) d ₆ = 2.0886 n _d3 = 1.49700 ν _d3 = 81.54
r ₇ = -6.7262 (aspherical surface) d ₇ = 0.7069
r ₈ = -3.9732 (aspherical surface) d ₈ = 1.4401 n _d4 = 1.58393 ν _d4 = 30.21
r ₉ = -9.3454 (aspherical surface) d ₉ = (variable)
r ₁₀ = ∞ d ₁₀ = 0.9600 n _d5 = 1.54771 ν _d5 = 62.84
r ₁₁ = ∞ d ₁₁ = 0.6000
r ₁₂ = ∞ d ₁₂ = 0.5000 n _d6 = 1.51633 ν _d6 = 64.14
r ₁₃ = ∞ d ₁₃ = 0.5000
r ₁₄ = ∞ (image plane)
Aspheric coefficient 1st surface K = 0
A ₄ = 1.3164 × 10 ^-4
A ₆ = 0.0000
Second side K = 0
A ₄ = -5.3057 × 10 ^-4
A ₆ = 3.3686 × 10 ^-5
Third side K = 0
A ₄ = -7.5233 × 10 ^-4
A ₆ = 2.8971 × 10 ^-5
4th surface K = 0
A ₄ = -5.1461 × 10 ^-4
A ₆ = 1.2110 × 10 ^-5
6th surface K = 0
A ₄ = -4.1026 × 10 ^-4
A ₆ = -5.9764 × 10 ^-5
Surface 7 K = 0
A ₄ = 2.7551 × 10 ^-3
A ₆ = 4.7060 × 10 ^-5
8th surface K = 0
A ₄ = 1.1630 × 10 ^-2
A ₆ = -3.4684 × 10 ^-5
9th surface K = 0
A ₄ = 7.6508 × 10 ^-3
A ₆ = 1.2631 × 10 ^-4
Zoom data (∞)
WE ST TE
f (mm) 6.00098 11.99744 17.94344
F _NO 3.0785 4.1576 5.2322
d ₄ 14.3857 4.7841 1.6000
d ₉ 9.2380 14.0573 18.8752.

Example 4
r ₁ = 75.3593 (aspherical surface) d ₁ = 1.0000 n _d1 = 1.74320 ν _d1 = 49.34
r ₂ = 4.8561 (aspherical surface) d ₂ = 1.5218
r ₃ = 7.4430 d ₃ = 1.7503 n _d2 = 1.90366 ν _d2 = 31.31
r ₄ = 13.6272 d ₄ = (variable)
r ₅ = ∞ (aperture) d ₅ = -0.3000
r ₆ = 4.6713 (aspherical surface) d ₆ = 3.5824 n _d3 = 1.49700 ν _d3 = 81.54
r ₇ = -6.6499 (aspherical surface) d ₇ = 0.2264
r ₈ = -18.5581 (aspherical surface) d ₈ = 1.0000 n _d4 = 1.68893 ν _d4 = 31.08
r ₉ = 15.0264 (aspherical surface) d ₉ = (variable)
r ₁₀ = ∞ d ₁₀ = 0.9600 n _d5 = 1.54771 ν _d5 = 62.84
r ₁₁ = ∞ d ₁₁ = 0.6000
r ₁₂ = ∞ d ₁₂ = 0.5000 n _d6 = 1.51633 ν _d6 = 64.14
r ₁₃ = ∞ d ₁₃ = 0.5000
r ₁₄ = ∞ (image plane)
Aspheric coefficient 1st surface K = 0
A ₄ = -5.9981 × 10 ^-5
A ₆ = 0.0000
Second side K = -0.6453
A ₄ = 2.3718 × 10 ^-4
A ₆ = 0.0000
6th surface K = 0
A ₄ = -1.1120 × 10 ^-3
A ₆ = 1.0075 × 10 ^-5
A ₈ = -1.6650 × 10 ^-5
Surface 7 K = 0
A ₄ = 3.2283 × 10 ^-3
A ₆ = -7.9085 × 10 ^-4
A ₈ = 3.2257 × 10 ^-5
8th surface K = 0
A ₄ = 4.5672 × 10 ^-3
A ₆ = -7.9080 × 10 ^-4
A ₈ = 2.1571 × 10 ^-5
Surface 9 K = 13.2252
A ₄ = 3.9321 × 10 ^-3
A ₆ = -1.0714 × 10 ^-4
Zoom data (∞)
WE ST TE
f (mm) 6.08056 11.78181 18.21488
F _NO 3.1976 4.2126 5.3670
d ₄ 14.5976 4.7205 1.0000
d ₉ 8.0615 12.0938 16.7288.

  Aberration diagrams at the time of focusing on an object point at infinity in Examples 1 to 4 are shown in FIGS. In these aberration diagrams, (a) is a wide-angle end, (b) is an intermediate state, (c) is spherical aberration (SA), astigmatism (AS), distortion (DT), and lateral chromatic aberration (CC) at the telephoto end. ). In each figure, “FIY” indicates the maximum image height.

Next, the angle of view and the parameter values related to the conditional expressions (1) to (14) in the above embodiments will be shown.

Conditional Example Example 1 Example 2 Example 3 Example 4
y ₁₀ ^* (maximum image height) (mm) 3.6 3.6 3.6 3.6
y ₁₀ ^* × 0.8 half angle of the corresponding <Note 1> 28.5 ° 28.3 ° 28.5 ° 27.0 °
Half field angle corresponding to y * 10 x0.6 <Note 1> 21.0 ° 20.9 ° 21.0 ° 20.3 °
WE half angle of view <Note 2> 32.6 ° 32.5 ° 32.6 ° 31.7 °
ST half angle of view 17.1 ° 17.1 ° 17.1 ° 17.2 °
TE half angle of view 11.4 ° 11.4 ° 11.4 ° 11.1 °
y ₀₈ ^* / (f _W · tanω _08W ) <Note 1> 0.88479 0.89253 0.88434 0.93045
( _Dy ^* / dy) _{y08 *} 0.69665 0.70875 0.68859 0.82344
( _Dy ^* / dy) _{y00 *} 1 1 1 1
a (μm) 2.25 2.25 2.25 2.25
y ₁₀ ^* / a 1.6 1.6 1.6 1.6
F _W / a 1.39 1.35 1.37 1.42
d1 / y ₁₀ ^* 0.44128 0.41603 0.41100 0.42272
R _11R / R _12F 0.78387 0.76391 0.70631 0.65244
(R _11F + R _11R ) / (R _11F −R _11R ) 0.85834 0.78802 0.68741 1.13776
n1 1.74320 1.74320 1.74320 1.74320
t1 / y ₁₀ ^* 1.17178 1.12906 1.13353 1.18670
β _T -1.45165 -1.60006 -1.49875 -1.37437
t2 / y ₁₀ ^* 1.02267 1.20428 1.17656 1.33578
D _12T / y ₁₀ ^* 0.44444 0.44444 0.44444 0.19444
ds / y ₁₀ ^* -0.13889 -0.13889 -0.13889 -0.08333
P _W / y ₁₀ ^* 5.21781 4.82278 5.12956 5.15219
(R _22F + R _22R ) / (R _22F −R _22R ) -3.72371 -4.67399 -2.47917 0.10516
<Note 1> Calculated before distortion correction.
<Note 2> Although the half angle of view corresponding to the maximum image height y ₁₀ ^* includes a value including distortion, in each embodiment, it is assumed that distortion is corrected by image processing near the wide angle end. Therefore, the corrected half angle of view is shown. In the correction, the half angle of view corresponding to y ₁₀ ^* × 0.6 is substantially unchanged before and after the correction.

  An example of an electronic photographing apparatus, particularly a digital camera, a video camera, and an information processing apparatus, which forms an object image with the zoom lens according to the present invention as described above and receives the image with an image sensor such as a CCD. It can be used for personal computers, telephones, especially mobile phones that are convenient to carry. The embodiment is illustrated below.

  9 to 11 are conceptual diagrams of a configuration in which a zoom lens according to the present invention is incorporated in a photographing optical system 41 of a digital camera. 9 is a front perspective view showing the appearance of the digital camera 40, FIG. 10 is a rear front view thereof, and FIG. 11 is a schematic perspective plan view showing the configuration of the digital camera 40. However, FIGS. 9 and 11 show a state in which the photographing optical system 41 is not retracted. In this example, the digital camera 40 includes a photographing optical system 41 having a photographing optical path 42, a finder optical system 43 having a finder optical path 44, a shutter 45, a flash 46, a liquid crystal display monitor 47, a focal length change button 61, a setting. When the photographing optical system 41 is retracted, including the change switch 62, the photographing optical system 41, the finder optical system 43, and the flash 46 are covered with the cover 60 by sliding the cover 60. When the cover 60 is opened and the camera 40 is set to the photographing state, the photographing optical system 41 enters the non-collapsed state shown in FIG. 11. When the shutter 45 arranged on the upper part of the camera 40 is pressed, the photographing optical system is linked. Photographing is performed through the system 41, for example, the zoom lens of the first embodiment. An object image formed by the photographic optical system 41 is formed on the imaging surface of the CCD 49 via a low-pass filter LF subjected to IR cut coating and a cover glass CG. The object image received by the CCD 49 is displayed as an electronic image on the liquid crystal display monitor 47 provided on the back of the camera via the processing means 51. Further, the processing means 51 is connected to a recording means 52 so that a photographed electronic image can be recorded. The recording means 52 may be provided separately from the processing means 51, or may be configured to perform recording / writing electronically using a floppy disk, memory card, MO, or the like. Further, it may be configured as a silver salt camera in which a silver salt film is arranged in place of the CCD 49.

  Further, a finder objective optical system 53 is disposed on the finder optical path 44. The finder objective optical system 53 includes a plurality of lens groups (three groups in the figure) and two prisms. The finder objective optical system 53 includes a zoom optical system whose focal length changes in conjunction with the zoom lens of the photographing optical system 41. The object image formed by the finder objective optical system 53 is formed on the field frame 57 of the erecting prism 55 that is an image erecting member. Behind the erecting prism 55 is an eyepiece optical system 59 that guides the erect image to the observer eyeball E. A cover member 50 is disposed on the exit side of the eyepiece optical system 59.

  In the digital camera 40 configured in this manner, the photographing optical system 41 has a high performance and a small size and can be retracted, so that a high performance and a small size can be realized.

  Next, a personal computer which is an example of an information processing apparatus in which the zoom lens according to the present invention is incorporated as an objective optical system is shown in FIGS. 12 is a front perspective view with the cover of the personal computer 300 opened, FIG. 13 is a sectional view of the photographing optical system 303 of the personal computer 300, and FIG. 14 is a side view of the state of FIG. As shown in FIGS. 12 to 14, the personal computer 300 includes a keyboard 301 for a writer to input information from the outside, information processing means and recording means not shown, and a monitor for displaying information to the operator. 302 and a photographing optical system 303 for photographing the operator himself and surrounding images. Here, the monitor 302 may be a transmissive liquid crystal display element that is illuminated from the back by a backlight (not shown), a reflective liquid crystal display element that reflects and displays light from the front, a CRT display, or the like. Further, in the drawing, the photographing optical system 303 is built in the upper right of the monitor 302. However, the imaging optical system 303 is not limited to the place, and may be anywhere around the monitor 302 or the keyboard 301.

  The photographic optical system 303 includes an objective lens 112 including a zoom lens (abbreviated in the drawing) according to the present invention and an image sensor chip 162 that receives an image on a photographic optical path 304. These are built in the personal computer 300.

  Here, an optical low-pass filter F is additionally attached on the image sensor chip 162 to be integrally formed as an image pickup unit 160, and can be fitted and attached to the rear end of the lens frame 113 of the objective lens 112 with one touch. Therefore, the center alignment of the objective lens 112 and the image sensor chip 162 and the adjustment of the surface interval are unnecessary, and the assembly is simple. A cover glass 114 for protecting the objective lens 112 is disposed at the tip of the lens frame 113. The zoom lens driving mechanism in the lens frame 113 is not shown.

  The object image received by the image sensor chip 162 is input to the processing means of the personal computer 300 via the terminal 166 and displayed on the monitor 302 as an electronic image. FIG. A rendered image 305 is shown. The image 305 can also be displayed on the personal computer of the communication partner from a remote location via the processing means, the Internet, or the telephone.

  Next, a telephone which is an example of an information processing apparatus in which the zoom lens according to the present invention is incorporated as a photographing optical system, particularly a portable telephone which is convenient to carry is shown in FIG. 15A is a front view of the mobile phone 400, FIG. 15B is a side view, and FIG. 15C is a cross-sectional view of the photographing optical system 405. As shown in FIGS. 15A to 15C, the mobile phone 400 includes a microphone unit 401 that inputs an operator's voice as information, a speaker unit 402 that outputs the voice of the other party, and an operator who receives information. An input dial 403 for inputting information, a monitor 404 for displaying information such as a photographed image and a telephone number of the operator and the other party, a photographing optical system 405, an antenna 406 for transmitting and receiving communication radio waves, and an image And processing means (not shown) for processing information, communication information, input signals, and the like. Here, the monitor 404 is a liquid crystal display element. In the drawing, the arrangement positions of the respective components are not particularly limited to these. The photographing optical system 405 includes an objective lens 112 including a zoom lens (abbreviated in the drawing) according to the present invention disposed on a photographing optical path 407, and an image sensor chip 162 that receives an object image. These are built in the mobile phone 400.

  Here, an optical low-pass filter F is additionally attached on the image sensor chip 162 to be integrally formed as an image pickup unit 160, and can be fitted and attached to the rear end of the lens frame 113 of the objective lens 112 with one touch. Therefore, the center alignment of the objective lens 112 and the image sensor chip 162 and the adjustment of the surface interval are unnecessary, and the assembly is simple. A cover glass 114 for protecting the objective lens 112 is disposed at the tip of the lens frame 113. The zoom lens driving mechanism in the lens frame 113 is not shown.

  The object image received by the imaging element chip 162 is input to the processing means (not shown) via the terminal 166 and displayed as an electronic image on the monitor 404, the monitor of the communication partner, or both. . Further, when transmitting an image to a communication partner, the processing means includes a signal processing function for converting information of an object image received by the image sensor chip 162 into a signal that can be transmitted.

  The electronic imaging apparatus of the present invention described above can be configured as follows, for example.

[1] It has a plurality of lens groups, and the distance between the lens groups is variable at the time of zooming or focusing, and the lens group G1 closest to the object has an aspherical surface and a negative lens component and a positive lens component. A zoom lens having two components and an electronic image sensor located on the image side thereof, and processing image data obtained by capturing an image formed through the zoom lens with the electronic image sensor In an electronic imaging device capable of outputting as image data with a changed shape,
An electronic imaging apparatus characterized in that the zoom lens satisfies the following conditions.

(1) 0.7 <y ₀₈ ^* / (f _W · tan ω _08W ) <0.96
However, if the distance (maximum image height) from the center to the farthest point in the effective imaging plane (in the imaging-capable plane) of the electronic imaging device is y ₁₀ ^* , y ₀₈ ^* = 0.8 y ₁₀ ^* , ω _08W is an angle with respect to the optical axis in the object direction corresponding to the image point connecting from the center on the imaging surface at the wide-angle end to the position of y ₀₈ ^* .

[2] It has a plurality of lens groups, and each lens group interval is variable at the time of zooming or focusing, and the lens group G1 closest to the object has an aspherical surface and a negative lens component and a positive lens component. A zoom lens having two components and an electronic image sensor located on the image side thereof, and processing image data obtained by capturing an image formed through the zoom lens with the electronic image sensor In an electronic imaging device capable of outputting as image data with a changed shape,
An electronic image pickup apparatus satisfying the following condition when the zoom lens is focused on any object distance of 50 times or more of f _W :

(1) 0.7 <y ₀₈ ^* / (f _W · tan ω _08W ) <0.96
However, if the distance (maximum image height) from the center to the farthest point in the effective imaging plane (in the imaging-capable plane) of the electronic imaging device is y ₁₀ ^* , y ₀₈ ^* = 0.8 y ₁₀ ^* , ω _08W is an angle with respect to the optical axis in the object direction corresponding to the image point connecting from the center on the imaging surface at the wide-angle end to the position of y ₀₈ ^* .

    [3] The electronic imaging apparatus as described in 1 or 2 above, wherein the following condition is satisfied.

(2) 1.2 <y ₁₀ ^* / a <6.0
Where y ₁₀ ^* is the distance (maximum image height) from the center to the farthest point in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging device, the unit is mm, and a is the long side of the electronic imaging device The distance between pixels in the direction, the unit is μm.

    [4] The electronic imaging apparatus as described in 1 or 2 above, wherein the following condition is satisfied.

(3) F _W ≧ 1.1a (μm)
Here, _FW is the release F value at the wide-angle end, a is the distance between pixels in the long side direction of the electronic image sensor, and the unit is μm.

    [5] The air gap d1 on the optical axis of the negative lens component and the positive lens component of the lens group G1 closest to the object in the zoom lens of the electronic imaging apparatus satisfies the following condition 1 or 2. The electronic imaging apparatus according to 2.

(4) 0.3 <d1 / y 10 * <0.6
However, the distance (maximum image height) y ₁₀ ^* from the center to the farthest point from the center in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging element is 0 <y ₁₀ ^* <6 (mm).

    [6] The electronic imaging device as described in [1] or [2], wherein the negative lens component and the positive lens component of the lens group G1 closest to the object in the zoom lens of the electronic imaging device satisfy the following conditions.

(5) 0.55 <R _11R / R _12F <0.95
However, R _11R is the most image side surface of the negative lens component of the lens unit G1 closest to the object side, and R _12F is the curvature of the most object side surface of the positive lens component of the lens unit G1 closest to the object side on the optical axis. Radius.

    [7] The negative lens component of the lens group G1 closest to the object side in the zoom lens of the electronic imaging apparatus has a shape factor and a medium refractive index that satisfy both of the following conditions: Electronic imaging device.

(6) 0.0 <(R _11F + R _11R ) / (R _11F −R _11R ) <1.5
(7) 1.55 <n1
Where R _11F and R _11R are the radiuses of curvature on the optical axis of the most object side surface and the most image side surface of the negative lens component of the most object side lens group G1, respectively, and n1 is the center of the negative lens component. It is the refractive index of a thick lens element.

    [8] The thickness t1 on the optical axis from the most object side surface to the most image side surface of the lens unit G1 closest to the object side in the zoom lens of the electronic imaging apparatus satisfies the following condition. 3. The electronic imaging apparatus according to 1 or 2 above.

(8) 0.7 <t1 / y 10 * <1.35
However, the distance (maximum image height) y ₁₀ ^* from the center to the farthest point from the center in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging element is 0 <y ₁₀ ^* <6 (mm).

    [9] The electronic imaging according to [1] or [2], wherein the lens group G1 closest to the object side in the zoom lens of the electronic imaging apparatus includes two lens elements, a negative lens and a positive lens, in order from the object side. apparatus.

    [10] The lens group G2 adjacent to the image side of the most object side lens group G1 in the zoom lens of the electronic imaging apparatus always moves toward the object side when zooming from the wide angle side to the telephoto side. 3. The electronic imaging apparatus as described in 1 or 2 above, wherein the following conditions are satisfied.

(9) 1.3 <−β _T <2.1
Where β _T is the lateral magnification of the lens group G2 at the telephoto end. Here, the distance (maximum image height) y ₁₀ ^* from the center to the farthest point from the center in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging device is 0 <y ₁₀ ^* <6 (mm). .

    [11] The lens group G2 adjacent to the image side of the most object side lens group G1 in the zoom lens of the electronic imaging apparatus always moves toward the object side when zooming from the wide-angle side to the telephoto side. 3. The electronic imaging apparatus as described in 1 or 2 above, wherein the following conditions are satisfied.

(10) 0.7 <t2 / y 10 * <1.6
Here, t2 is the distance on the optical axis from the most object side surface of the lens group G2 to the most image side surface. Here, the distance (maximum image height) y ₁₀ ^* from the center to the farthest point from the center in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging device is 0 <y ₁₀ ^* <6 (mm). .

    [12] The electronic imaging apparatus according to 1 or 2, wherein the lens group G2 adjacent to the image side of the lens group G1 closest to the object side in the zoom lens of the electronic imaging apparatus satisfies the following condition.

(11) 0.1 <D _12T / y ₁₀ ^* <0.7
(12) -0.7 <ds / y 10 * <0
Where D _12T is the distance on the optical axis from the most image-side surface of the lens group G1 to the object-side surface of the lens group G2 at the telephoto end and at infinity, and ds is the light beam on the outermost axis. The distance between the position of the intersection of the surface including the aperture part (inner diameter part) of the aperture stop and the optical axis and the top of the lens group G2 closest to the object side, and the negative value is the object side of the latter with respect to the former Is the case. Here, the distance (maximum image height) y ₁₀ ^* from the center to the farthest point from the center in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging device is 0 <y ₁₀ ^* <6 (mm). .

    [13] The electronic imaging according to 1 or 2, wherein the zoom lens of the electronic imaging apparatus has an aperture stop on the image side of the lens group G1 closest to the object side, and the aperture stop satisfies the following conditions: apparatus.

(13) 4.0 <P _W / y ₁₀ ^* <6.5
Here, P _W is the distance on the optical axis from the most object-side surface to the aperture stop position at the wide-angle end. Here, the distance (maximum image height) y ₁₀ ^* from the center to the farthest point from the center in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging device is 0 <y ₁₀ ^* <6 (mm). .

    [14] The lens group G2 adjacent to the image side of the lens group G1 closest to the object side in the zoom lens of the electronic imaging apparatus is composed of two components of a positive lens component and a negative lens component in order from the object side. 3. The electronic imaging apparatus according to 1 or 2 above.

    [15] The lens group G2 adjacent to the image side of the lens group G1 closest to the object side in the zoom lens of the electronic imaging apparatus is composed of two lens elements in order from the object side: a positive lens and a negative lens. 3. The electronic imaging apparatus according to 1 or 2 above.

    [16] The lens group G2 adjacent to the image side of the lens group G1 closest to the object side in the zoom lens of the electronic imaging apparatus is composed of two components of a positive lens component and a negative lens component in order from the object side. 3. The electronic imaging device as described in 1 or 2 above, wherein the lens component satisfies the following conditions.

(14) -10 <( _R22F + _R22R ) / ( _{R22F- R22R} ) <0.5
Here, R _22F and R _22R are the radii of curvature on the optical axis of the most object side surface and the most image side surface in the negative lens component of the lens group G2, respectively.

FIG. 3 is a lens cross-sectional view at the wide-angle end (a), an intermediate state (b), and a telephoto end (c) when focusing on an object point at infinity according to the first exemplary embodiment of the zoom lens used in the electronic imaging device of the present invention. FIG. 6 is a lens cross-sectional view similar to FIG. 1 of a zoom lens according to Embodiment 2. FIG. 6 is a lens cross-sectional view similar to FIG. 1 of a zoom lens according to Example 3. FIG. 6 is a lens cross-sectional view similar to FIG. 1 illustrating a zoom lens according to a fourth exemplary embodiment. FIG. 6 is an aberration diagram for Example 1 upon focusing on an object point at infinity. FIG. 6 is an aberration diagram for Example 2 upon focusing on an object point at infinity. FIG. 10 is an aberration diagram for Example 3 upon focusing on an object point at infinity. FIG. 10 is an aberration diagram for Example 4 upon focusing on an object point at infinity. It is a front perspective view which shows the external appearance of the digital camera incorporating the zoom lens by this invention. FIG. 10 is a rear perspective view of the digital camera of FIG. 9. It is sectional drawing of the digital camera of FIG. It is the front perspective view which opened the cover of the personal computer incorporating the zoom lens by this invention as an objective optical system. It is sectional drawing of the imaging optical system of a personal computer. It is a side view of the state of FIG. FIG. 2 is a front view (a), a side view (b), and a sectional view (c) of the photographing optical system of a mobile phone in which the zoom lens according to the present invention is incorporated as an objective optical system.

Explanation of symbols

G1 ... 1st lens group G2 ... 2nd lens group S ... Aperture stop L ... Low pass filter G ... Cover glass I ... Image plane E ... Observer eyeball F ... Optical low pass filter 40 ... Digital camera 41 ... Shooting optical system 42 ... Optical path for photographing 43 ... finder optical system 44 ... optical path for finder 45 ... shutter 46 ... flash 47 ... liquid crystal display monitor 49 ... CCD
DESCRIPTION OF SYMBOLS 50 ... Cover member 51 ... Processing means 52 ... Recording means 53 ... Finder objective optical system 55 ... Erect prism 57 ... Field frame 59 ... Eyepiece optical system 60 ... Cover 61 ... Focal length change button 62 ... Setting change switch 112 ... Objective Lens 113 ... Mirror frame 114 ... Cover glass 160 ... Imaging unit 162 ... Imaging element chip 166 ... Terminal 300 ... PC 301 ... Keyboard 302 ... Monitor 303 ... Shooting optical system 304 ... Shooting optical path 305 ... Image 400 ... Mobile phone 401 ... Microphone unit 402 ... Speaker unit 403 ... Input dial 404 ... Monitor 405 ... Shooting optical system 406 ... Antenna 407 ... Shooting optical path

Claims (6)

In order from the object side, a zoom lens composed of a first lens group G1 having negative refractive power, an aperture stop, and a second lens group having positive refractive power, and electronic imaging located on the image side of the zoom lens Having an element,
The distance between the lens groups of the first lens group G1 and the second lens group G2 is variable at the time of zooming or focusing, and the first lens group G1 has two components: a negative lens component having an aspheric surface and a positive lens component. Tona is, said image formed through the zoom lens by processing the image data obtained by imaging by the electronic image pickup device, the electronic imaging device capable of outputting the shape as image data obtained by changing the Because
An electronic imaging apparatus characterized in that the zoom lens satisfies the following conditions.
(1) 0.7 <y ₀₈ ^* / (f _W · tan ω _08W ) <0.96
(4) "'0.3<d1 / y 10 * ≦ 0.44128
However, if the distance (maximum image height) from the center to the farthest point in the effective imaging plane (in the imaging-capable plane) of the electronic imaging device is y ₁₀ ^* , y ₀₈ ^* = 0.8 y ₁₀ ^* , ω _08W is Ri angle der respect to the optical axis of the corresponding object point direction to image points connecting the y ₀₈ ^* position from a center on the imaging surface at the wide angle end, y ₁₀ ^{* _{is, 0 <y 10 * <6}} (mm D1 is an air space on the optical axis of the negative lens component and the positive lens component of the first lens group G1, and the lens component is a lens or a lens surface having a thickness of less than 1 mm made of resin or the like. This means a compound lens in which a thin lens is adhered and cured. Electronic imaging apparatus according to claim 1, characterized by satisfying the following condition.
(2) 1.2 <y ₁₀ ^* / a <6.0
Where y ₁₀ ^* is the distance (maximum image height) from the center to the farthest point in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging device, the unit is mm, and a is the long side of the electronic imaging device The distance between pixels in the direction, the unit is μm.
The negative lens component of the first lens group G1, the electronic imaging device according to claim 1, wherein the shape factor and the medium refractive index satisfies both the following conditions.
(6) 0.0 <(R _11F + R _11R ) / (R _11F −R _11R ) <1.5
(7) 1.55 <n1
Where R _11F and R _11R are the radiuses of curvature on the optical axis of the most object side surface and the most image side surface of the negative lens component of the most object side lens group G1, respectively, and n1 is the center of the negative lens component. It is the refractive index of a thick lens element. Electronic imaging device according to claim 1, wherein the thickness t1 of the optical axis to the surface of the most image side from the surface on the most object side of the first lens group G1 satisfies the following condition.
(8) 0.7 <t1 / y 10 * <1.35
However, the distance (maximum image height) y ₁₀ ^* from the center to the farthest point from the center in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging element is 0 <y ₁₀ ^* <6 (mm). Wherein the second lens group G2, in time of zooming toward the telephoto side from the wide angle side, always moves to the object side, the electronic imaging device according to claim 1, characterized by satisfying the following condition.
(10) 0.7 <t2 / y10 * <1.6
Here, t2 is the distance on the optical axis from the most object-side surface to the most image-side surface of the second lens group G2. Here, the distance (maximum image height) y10 * from the center to the farthest point in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging device is 0 <y10 * <6 (mm). In order from the object side, a zoom lens including a first lens group G1 having negative refractive power, an aperture stop, and a second lens group having positive refractive power, and electronic imaging located on the image side of the zoom lens Having an element,
The distance between the lens groups of the first lens group G1 and the second lens group G2 is variable at the time of zooming or focusing, and the first lens group G1 has two components, a negative lens component having an aspheric surface and a positive lens component. An electronic image pickup device capable of processing image data obtained by picking up an image formed through the zoom lens with the electronic image pickup device and outputting the processed image data as image data having a changed shape There,
An electronic imaging apparatus characterized in that the zoom lens satisfies the following conditions.
(1) 0.7 <y ₀₈ ^* / (F _W ・ Tanω _08W ) <0.96
(6) "'0.0 <(R _11F + R _11R ) / (R _11F -R _11R <0.9
(7) 1.55 <n1
However, the distance (maximum image height) from the center to the farthest point in the effective imaging plane (in the plane where imaging is possible) of the electronic imaging element is y _Ten ^* And y ₀₈ ^* = 0.8y _Ten ^* , Ω _08W Is y from the center on the imaging surface at the wide-angle end. ₀₈ ^* The angle with respect to the optical axis in the object direction corresponding to the image point connected to the position of y _Ten ^* Is 0 <y _Ten ^* <6 (mm), R _11F , R _11R Is the radius of curvature on the optical axis of the most object side surface and the most image side surface in the negative lens component of the most object side lens group G1, and n1 is the lens element with the thickest center thickness of the negative lens component. The lens component means a compound lens in which a single lens or a thin lens made of resin or the like and having a thickness of less than 1 mm is adhered and cured on the lens surface.

Images