JP2003344767A - Zoom lens and electronic image pickup device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a zoom lens which does not require start-up time for a usable state found in a collapsible mount type lens barrel, which is desirable in terms of water-proof and dust-proof effects, and which realizes a camera whose depth direction is extremely thin, and which has high optical specification performance, and an electronic image pickup device having the zoom lens. <P>SOLUTION: The zoom lens is provided with a 1st negative lens group G1 including a catoptric element R1 for bending an optical path and fixed at the time of varying power, a 2nd negative lens group G2 moving only to an object side in the case of varying power from a wide angle end to a telephoto end, a 3rd lens group G3 moving differently from the 2nd lens group G2 in the case of varying power, and a 4th lens group G4 having an aspherical surface in order from the object side. Then, two lens groups, that is, the 2nd and the 3rd lens groups G2 and G3 are constituted of three or less lens components in total including one or more doublet components, and the zoom lens satisfies a following conditional expression; 1.0<-βR<SB>t</SB><2.6. Where βR<SB>t</SB>is the synthetic magnification of the 2nd lens group G2 and succeeding lens groups at the telephoto end at the time of focusing on an infinity object point. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens and an electronic image pickup apparatus having the zoom lens, and particularly to a video camera and a digital camera which are thinned in a depth direction by devising an optical system portion such as a zoom lens. The present invention relates to an electronic image pickup device and a zoom lens used therein.

[0002]

2. Description of the Related Art In recent years, a digital camera (electronic camera) has been attracting attention as a next-generation camera that replaces a silver salt 35 mm film (135 format) camera. further,
It has come to have several categories in a wide range from high-performance types for business to popular types that are portable. In the present invention, attention is particularly paid to a portable popular type category, and it is an object of the present invention to provide a technique for realizing a video camera and a digital camera which are thin and have good usability while ensuring high image quality.

The biggest bottleneck in thinning the depth direction of a camera is the thickness from the most object side surface to the image pickup surface of an optical system, particularly a zoom lens system. The mainstream of recent technology for thinning a camera body is to employ a so-called collapsible lens barrel that has an optical system protruding from the inside of the camera body at the time of shooting, but is housed when carrying. As an example of an optical system having a possibility of effectively reducing the thickness by adopting a retractable lens barrel, JP-A-11-194274, JP-A-11-287953, and JP-A-2000-
There is one described in Japanese Patent Publication No. 9997. These have, in order from the object side, a first group having a negative refractive power and a second group having a positive refractive power, and both the first group and the second group move during zooming.

[0004]

However, if a retractable lens barrel is used, it takes time to start the lens from the housed state to the used state, which is not preferable in terms of usability. If the lens unit closest to the object side is movable, it is not preferable in terms of waterproof and dustproof.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to set up a camera in a use state as seen in a collapsible lens barrel (lens extension time). ), It is also waterproof and dustproof,
Further, since the camera has an extremely thin depth direction, it is easy to adopt a configuration in which the optical path (optical axis) of the optical system is bent by a reflective optical element, and has high optical specification performance such as zoom ratio, angle of view, F value, and small aberration. An object of the present invention is to provide a zoom lens and an electronic image pickup apparatus having the same.

[0006]

In order to achieve the above object, the zoom lens according to the first aspect of the present invention has, in order from the object side, a negative refractive power, and a zoom lens including a reflective optical element for bending an optical path. A first lens unit that is fixed at the time of zooming, a second lens unit that has a positive refractive power, and that moves only to the object side when zooming from the wide-angle end to the telephoto end, and the second lens unit when zooming It has a third lens group that moves differently from the lens group, and a fourth lens group having an aspherical surface, and two lens groups of the second lens group and the third lens group It is characterized by being composed of a total of three or less lens components including the above-mentioned cemented lens components and satisfying the following conditional expression (1). 1.0 <−β _Rt <2.6 (1) where β _Rt is a composite magnification at the telephoto end when focusing on an object point at infinity after the second lens unit.

The zoom lens according to the second aspect of the present invention has, in order from the object side, a first lens group having a negative refracting power and fixed during zooming, which includes a reflective optical element for bending the optical path, and a positive lens group. A second lens group having a refracting power of 2 and moving only to the object side when zooming from the wide-angle end to the telephoto end, and a third lens that moves differently from the second lens group when zooming. And a fourth lens group having an aspherical surface, wherein
The lens unit is composed of, in order from the object side, a front sub-group having a negative lens with a convex surface facing the object side, a reflective optical element for bending the optical path, and a rear sub-group having negative refracting power. , The following conditional expressions (7) and (8) are satisfied. 0.5 <(R _11F + R _11R ) / (R _11F −R _11R ) <5.0 (7) 0 <f ₁₁ / f ₁₂ <1.2 (8) where R _11F is the first lens group. R _11R is the radius of curvature on the optical axis of the object side surface of the negative lens of the front side subgroup of, and R _11R is the radius of curvature of the image side surface of the negative lens of the front side subgroup of the first lens group,
f ₁₁ is the focal length of the front sub-group of the first lens group, and f ₁₂ is the focal length of the rear sub-group of the first lens group.

An electronic image pickup apparatus according to the third aspect of the present invention is characterized by including the zoom lens of the second aspect of the present invention and an electronic image pickup element arranged on the image side thereof.

In the electronic image pickup apparatus according to the fourth aspect of the present invention, the first lens group includes a front subgroup having a negative lens having a convex surface directed toward the object side, and the optical path bent in order from the object side. A zoom lens according to the first aspect of the present invention, which includes a reflective optical element and a rear subgroup having a negative refractive power, and satisfies the following conditional expressions (3) and (4), and is disposed on the image side thereof. And an electronic image pickup device. 0 <L / R _21C <1.4 (3) 15 <ν _21F −ν _21R (4) where L is the diagonal length of the effective image pickup area of the electronic image pickup device, R
_21C is the radius of curvature of the cemented surface in the second lens group on the optical axis, ν _21F is the Abbe number of the medium of the lens on the object side of the cemented surface in the second lens group on the d-line basis, and ν _21R is the second It is the Abbe number on the d-line basis of the medium of the lens on the image side of the cemented surface in the lens group.

Also, in the electronic image pickup device according to the fifth aspect of the present invention, the front side sub-group is composed of a negative lens having one aspherical surface, and the rear side sub-group has two lens components having different signs of refractive power. And the second condition that satisfies the following conditional expression (9)
Alternatively, the zoom lens according to the fourth aspect of the invention and the electronic image pickup device arranged on the image side thereof are provided. 0.4 <(R _12R / R _13F ) ^P <1.6 (9) where R _12R is the object side surface of the air lens formed between the two lens components of the rear subgroup of the first lens group. The radius of curvature on the optical axis, R _13F is the radius of curvature on the optical axis of the image side surface of the air lens formed between the two lens components of the rear sub-group of the first lens group, and P is 2 The order of the lens components from the object side is P = 1 when the negative lens component and the positive lens component are arranged in this order, and P = −1 when the positive lens component and the negative lens component are arranged in this order. To do.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of the embodiments, the reasons and effects of adopting the above-mentioned configuration in the present invention will be described. In the electronic imaging device of the present invention, in order from the object side, it has a negative refractive power, has a first lens group that is fixed during zooming and includes a reflective optical element for bending the optical path, and has a positive refractive power.
A second lens group that moves only to the object side when zooming from the wide-angle end to the telephoto end, a third lens group that moves differently from the second lens group when zooming, and a fourth lens group having an aspherical surface. The lens group and the lens system constitute a zoom lens system in which the optical path is bent, and this is used. In this way, by providing the reflective optical element for bending the optical path in the first lens group closest to the object side, the depth direction of the camera can be made thin. If the lens group having the bending function is fixed during zooming, mechanical complexity can be avoided.

Further, according to the present invention, the second lens group and the third lens group are configured to move differently, mainly for the purpose of correcting the magnification change and the image point position variation due to the magnification change. . In particular, since the second lens group is a lens group having a main variable magnification function, when the magnification is changed from the wide-angle end to the telephoto end, it is moved only to the object side. Also, the fourth
The lens group has a role of correcting residual off-axis aberrations generated in the first to third lens groups, and it is effective to introduce an aspherical surface. Further, in the case of the zoom lens system having such a configuration, the total of the two lens groups of the second lens group and the third lens group including one or more cemented lens components in total is 3
Even with a small number of lens components such as the following, it is possible to correct fairly off-axis aberrations (in the present application, the lens component means that only the lens surface closest to the object and the lens surface closest to the image are A lens that is in contact with the space and does not include an air space between them.
Use as a unit. ).

Further, it is preferable that the following conditional expression (1) is satisfied. 1.0 <−β _Rt <2.6 (1) where β _Rt is a composite magnification at the telephoto end when focusing on an object point at infinity after the second lens unit. If the upper limit value or the lower limit value of the conditional expression (1) is exceeded, the amount of change in the relative distance between the second lens group and the third lens group becomes large and the moving lens group is moved. It is easy to waste space for the work. It is even better to satisfy the following conditional expression (1 ′). 1.2 <-β _Rt <2.3 (1 ') Furthermore, it is best if the following conditional expression (1 ") is satisfied: 1.4 <-β _Rt <2.0 (1")

In particular, the second lens group, in order from the object side,
By constructing a cemented lens component of a positive lens having an aspherical surface and a negative lens, and a positive lens, conditional expression (1) is satisfied with a small number of lenses, and aberration changes from the wide-angle end to the telephoto end are extremely small. It becomes possible to do. At the same time, it is advantageous in terms of F-number change during zooming, the exit pupil position does not become too close to the image plane, and the exit pupil position does not vary much during zooming. Although the degree of aberration deterioration per unit amount of relative eccentricity (decentering sensitivity) between the two lens components in the second lens group tends to be large, it is preferable to satisfy the following conditional expression (2). 0.7 <R _21R / R _21F <1.6 (2) where R _21R is the radius of curvature on the optical axis of the most image-side surface of the cemented lens component of the second lens group, and R _21F is the second It is the radius of curvature on the optical axis of the surface of the cemented lens component of the lens unit closest to the object side.

When the value exceeds the upper limit of conditional expression (2), it is advantageous for correction of spherical aberration, coma aberration, and astigmatism of the entire system, but the effect of mitigating decentration sensitivity due to cementing is small. On the other hand, when the value goes below the lower limit of conditional expression (2), it becomes difficult to correct spherical aberration, coma aberration, and astigmatism of all system aberrations. It is even better to satisfy the following conditional expression (2 ′). 0.75 <R _21R / R _21F <1.3 (2 ') Further, it is best if the following conditional expression (2 ") is satisfied: 0.8 <R _21R / R _21F <1.3 (2) ")

In addition to the above, if the following conditional expressions (3) and (4) are satisfied, it is good for chromatic aberration correction. 0 <L / R _21C <1.4 (3) 15 <ν _21F −ν _21R (4) where L is the diagonal length (mm) of the image sensor used, R
_21C is the radius of curvature on the optical axis of the cemented surface of the cemented lens component of the second lens group. It is assumed that the image sensor is used so that the angle of view at the wide-angle end includes 55 degrees or more. ν _21F is the Abbe number of the medium of the object side lens of the cemented lens component of the second lens group, and ν _21R is the Abbe number of the medium of the image side lens of the cemented lens component of the second lens group.

When the value goes below the lower limit of conditional expression (3), it is advantageous for correction of longitudinal chromatic aberration and lateral chromatic aberration, but chromatic aberration of spherical aberration is likely to occur, and particularly spherical aberration at the reference wavelength can be satisfactorily corrected. However, short-wavelength spherical aberration is not preferable because it causes an overcorrection state and causes color bleeding in an image. On the other hand, if the upper limit of conditional expression (3) is exceeded, axial chromatic aberration and lateral chromatic aberration will be undercorrected, or short-wave spherical aberration will be undercorrected. When the value goes below the lower limit of conditional expression (4), axial chromatic aberration is likely to be undercorrected. On the other hand, there is no combination of media that exceeds the upper limit of conditional expression (4) in nature. The following conditional expression
It is even better to satisfy at least one of (3 ') and (4'). 0.2 <L / R _21C <1.2 (3 ') 20 <ν _21F −ν _21R (4') Furthermore, at least one of the following conditional expressions (3 ") and (4") The best is to meet one. 0.4 <L / R _21C <1.0… (3 ") 25 <ν _21F −ν _21R … (4")

For the fourth lens group, the following conditional expression (5) should be satisfied. −0.4 <L / fD <0.6 (5) where L is the diagonal length of the effective image pickup area of the electronic image pickup device, and f
D is the focal length of the fourth lens group. When the value goes below the lower limit of conditional expression (5), the exit pupil position at the wide-angle end easily approaches the image plane. Is too large, and both are likely to cause shading. It is even better if the following conditional expression (5 ') is satisfied. -0.2 <L / fD <0.4 (5 ') Further, it is best if the following conditional expression (5 ") is satisfied: 0 <L / fD <0.2 (5")

Further, if the fourth lens unit is composed of two lenses, a positive lens and a negative lens, and the following conditional expression (6) is satisfied, chromatic aberration correction is good. 15 <ν _4P −ν _4N (6) where ν _4P is the Abbe number of the positive lens medium of the fourth lens group at the d-line standard, and ν _4N is the d-line reference of the negative lens medium of the fourth lens group. Is the Abbe number in. When the value goes below the lower limit of conditional expression (6), lateral chromatic aberration is likely to be undercorrected. on the other hand,
There is no natural combination of media that exceeds the upper limit of conditional expression (6). It is even better to satisfy the following conditional expression (6 ′). 20 <ν _4P −ν _4N (6 ′) Furthermore, it is best if the following conditional expression (6 ″) is satisfied: 25 <ν _4P −ν _4N (6 ”)

Next, the first lens group of the zoom lens of the present invention will be described in detail. In the zoom lens of the present invention, the first lens group has, in order from the object side, a front side sub group having a negative lens having a convex surface facing the object side, a reflective optical element for bending the optical path, and a negative refractive power. It consists of a rear subgroup. Since the optical path bending optical element requires a certain amount of optical path length, the entrance pupil tends to be deep, while in order to secure the magnification, the focal length after the second lens group tends to be long and the moving space tends to be large, The two are in conflict. For this reason, it is advisable to dispose the negative refracting power of the first lens group by the two optical elements and arrange them in front of and behind the optical path bending optical element. In that case, the following conditional expressions (7) and (8) should be satisfied. 0.5 <(R _11F + R _11R ) / (R _11F −R _11R ) <5.0 (7) 0 <f ₁₁ / f ₁₂ <1.2 (8) where R _11F is the first lens group. R _11R is the radius of curvature on the optical axis of the object side surface of the negative lens of the front side subgroup of, and R _11R is the radius of curvature of the image side surface of the negative lens of the front side subgroup of the first lens group,
f ₁₁ is the focal length of the front sub-group of the first lens group, and f ₁₂ is the focal length of the rear sub-group of the first lens group.

Conditional expression (7) is a conditional expression which defines the shape factor of the negative lens of the front sub-group of the first lens group.
If the upper limit of conditional expression (7) is exceeded, interference with the optical path bending optical element tends to occur, and avoiding interference increases the depth dimension, which is not preferable. On the other hand, when the value goes below the lower limit of conditional expression (7), it becomes difficult to correct aberrations such as distortion. Conditional expression
(8) is a conditional expression that defines the ratio of the focal lengths of the front sub-group and the rear sub-group of the first lens group. If the upper limit of conditional expression (8) is exceeded, the entrance pupil tends to become deep. On the other hand, when the value goes below the lower limit of the conditional expression (8), the focal length after the second lens group becomes long in order to secure the magnification, and the moving space tends to become large. It is even better to satisfy the following conditional expressions (7 ′) and (8 ′). 0.8 <(R _11F + R _11R ) / (R _11F −R _11R ) <4.0 (7 ′) 0 <f ₁₁ / f ₁₂ <1.0 (8 ′) Further, the following conditional expression ( It is best to satisfy 7 ") and (8"). _{1.0 <(R 11F + R 11R} ) / (R 11F -R 11R) <3.0 ... (7 ") 0 <f 11 / f 12 <0.8 ... (8")

In order to make the depth dimension thin, the front side sub-group is composed of one negative lens, so that an aspherical surface is introduced into the front side sub-group mainly for the purpose of correcting off-axis aberrations. It is preferable that the rear sub-group be made to bear the correction of the spherical aberration on the telephoto side, and that it be configured by two lens components. Furthermore, 2
Regarding the air lens portion formed by the two lens components, the following conditional expression (9) may be satisfied. 0.4 <(R _12R / R _13F ) ^P <1.6 (9) where R _12R is the object side surface of the air lens formed between the two lens components of the rear subgroup of the first lens group. The radius of curvature on the optical axis, R _13F, is the radius of curvature on the optical axis of the image side surface of the air lens formed between the two lens components of the rear sub-group of the first lens group. When the order of the two lens components from the object side is the negative lens component and the positive lens component in this order, P = 1, and when the positive lens component and the negative lens component are in the order, P = 1. = -1.

When the value goes below the lower limit of conditional expression (9), the higher-order component of the spherical aberration on the telephoto side becomes large, and the contrast of the image tends to be deteriorated. On the other hand, if the upper limit of conditional expression (9) is exceeded,
It tends to cause insufficient correction of spherical aberration on the telephoto side. It is better if the following conditional expression (9 ") is satisfied: 0.5 <(R _12R / R _13F ) ^P <1.4 (9 ') Further, if the following conditional expression (9") is satisfied, The best. 0.6 <(R _12R / R _13F ) ^P <1.2 (9 ")

At least one of the two lens components constituting the rear subgroup of the first lens unit is a cemented lens component in which a positive lens and a negative lens are cemented, and the positive lens constituting the cemented lens has a high refractive index. It is preferable to use a dispersion medium and a low dispersion medium for the negative lens. Further, it is preferable that the following conditional expressions (10) and (11) are satisfied. 3 <ν _A2N −ν _A2P <40 (10) 0.2 <Q · L / R _A2C <1.0 (11) where ν _A2N is a cemented lens component in the rear subgroup of the first lens group. _Is the Abbe number of the medium of the negative lens in the d-line standard, ν _A2P is the Abbe number of the medium of the positive lens of the cemented lens component in the rear subgroup of the first lens group in the d-line standard,
L is the diagonal length of the effective image pickup area of the electronic image pickup device, and R _A2C is the radius of curvature on the optical axis of the cemented surface of the cemented lens component in the rear subgroup of the first lens group. Further, when the cemented lens component in the rear subgroup of the first lens group is a negative lens and a positive lens in order from the object side, Q = 1, and when the object side is a positive lens and a negative lens, Q = -1. To do.

If the lower limit of conditional expression (10) is exceeded or the upper limit of conditional expression (10) is exceeded, it becomes difficult to simultaneously correct axial chromatic aberration and lateral chromatic aberration. If the lower limit of conditional expression (11) is not reached, chromatic aberration of spherical aberration is likely to occur, and even if spherical aberration at the reference wavelength can be corrected well, short-wavelength spherical aberration becomes an undercorrected state, causing color bleeding in the image. It is not preferable because it causes On the other hand, conditional expression (11)
If the value exceeds the upper limit of, the eccentricity sensitivity of joining increases, which is not preferable. It is even better if the following conditional expressions (10 ') and (11') are satisfied. 6 <ν _A2N −ν _A2P <35 (10 ') 0.3 <Q · L / R _A2C <0.8 (11') Further, the following conditional expressions (10 ") and (11") are satisfied. And the best. 9 <ν _A2N −ν _A2P <30 (10 ”) 0.4 <Q · L / R _A2C <0.65 (11”)

Focusing in the zoom lens of the present invention is preferably performed by moving the third lens group forward and backward on the optical axis. Also, if the fourth lens group is always fixed,
This is also preferable from the viewpoint of simplifying the mechanism and reducing aberration fluctuations during zooming and focusing.

By the way, in the case of the optical path bending type zoom lens as in the present invention, the rate of downsizing of the optical system accompanying the downsizing of the image pickup device is larger than that of the above-mentioned lens barrel collapsible zoom lens. Therefore, in order to make the camera thinner, the horizontal pixel pitch a (μm) of the electronic image sensor is set to the open F value at the wide angle end of the zoom lens by the following conditional expression (12) F ≧ a ... (12) It is effective to use the zoom lens of the present invention by using an electronic image pickup device that is small enough to satisfy the relationship. In that case, it is better to make the following measures.

As the image pickup device becomes smaller, the pixel pitch also becomes smaller proportionally, and the image quality deterioration due to the influence of diffraction cannot be ignored. In particular, when the relationship between the open F value at the wide-angle end and the horizontal pixel pitch a (μm) of the electronic image sensor to be used is reduced to satisfy the above conditional expression (12), only the open can be used. . Therefore, the inner diameter of the aperture stop that determines the F value is fixed, and the aperture stop is neither inserted nor removed or replaced. Then, at least one of the refracting surfaces adjacent to the aperture stop has a convex surface directed toward the aperture stop (corresponding to the refracting surface adjacent to the image side in the present invention), and a perpendicular line drawn from the aperture stop to the optical axis. Is located within 0.5 mm from the top of the convex surface, or the convex surface intersects or contacts the inner diameter of the aperture stop member including the back surface of the aperture stop portion. In this way, the space for the aperture stop, which has taken up a lot more space than before, becomes unnecessary,
It can save a lot of space and contribute significantly to downsizing.

For adjusting the light quantity, it is preferable to use a transmittance varying means instead of the aperture stop. The transmittance varying means is
Since there is no problem in putting it in any position of the optical path, it is better to put it in a space with a large margin. Especially in the case of the present invention,
It is preferable to insert it between the lens group that moves for zooming and the image pickup device. As the transmittance varying means, one whose transmittance is variable by voltage or the like may be used, or a plurality of filters having different transmittances may be combined by inserting / removing / inserting / removing. Further, it is preferable to dispose a shutter for adjusting the light receiving time of the light flux guided to the electronic image pickup device in a space different from the aperture stop.

Further, regarding the relationship between the open F value at the wide-angle end and the horizontal pixel pitch a (μm) of the electronic image sensor used,
If the conditional expression (12) (F ≧ a) is satisfied, the optical low-pass filter may be omitted. That is, the medium on the optical path between the zoom lens system and the image pickup element may be only air or an amorphous medium. This is because there are almost no frequency components that can cause aliasing distortion due to deterioration of the imaging characteristics due to diffraction and geometrical aberration. Alternatively, each of the optical elements between the zoom lens system and the electronic image pickup element has a medium boundary surface that is substantially flat and has no spatial frequency characteristic conversion action such as an optical low-pass filter. It may be configured.

The zoom lens used in the present invention preferably satisfies the following conditional expression (13). 1.8 <fT / fw (13) where fT is the focal length of the entire zoom lens system at the telephoto end, and fw is the focal length of the entire zoom lens system at the wide angle end. When the value goes below the lower limit of the conditional expression (13), the zoom ratio of the entire zoom lens system becomes smaller than 1.8. Furthermore, it is more preferable that fT / fw does not exceed 5.5. If it exceeds 5.5, the zoom ratio becomes large,
Since the amount of movement of the lens group that moves during zooming becomes too large, the size in the direction in which the optical path is bent increases, making it impossible to achieve a compact imaging device.

In the electronic image pickup device used in the present invention, it is premised that the total angle of view at the wide-angle end is 55 degrees or more. 55 degrees is the full angle of view at the wide-angle end that is usually required for electronic image pickup devices. Further, the wide-angle end angle of view in the electronic image pickup device is preferably 80 degrees or less. The wide-angle end angle of view is 80
If it exceeds the above range, distortion is likely to occur, and it becomes difficult to make the first lens group small. Therefore, it is difficult to reduce the thickness of the electronic image pickup device.

Finally, the requirements for making the infrared cut filter thinner will be described. In an electronic image pickup device, an infrared absorption filter having a certain thickness is usually inserted closer to the object side than the image pickup element so that infrared light does not enter the image pickup surface. To make the optical system short or thin,
Consider replacing the infrared absorption filter with a thin coating. Then, of course, the thickness is reduced by that amount, but there is a secondary effect. The transmittance at a wavelength of 600 nm is 80% closer to the object side than the image sensor behind the zoom lens system.
As described above, when a near infrared sharp cut coat having a transmittance at a wavelength of 700 nm of 8% or less is introduced, the transmittance in the near infrared region at a wavelength of 700 nm or more is lower than that of the absorption type, and
The transmittance on the red side is relatively high. Then, the magenta tendency on the bluish purple side, which is a drawback of a solid-state image sensor such as a CCD having a complementary color mosaic filter, is alleviated by gain adjustment, and color reproduction similar to that of a solid-state image sensor such as a CCD having a primary color filter can be obtained. Further, the color reproduction of not only primary colors and complementary colors but also those having a strong reflectance in the near infrared region such as plants and human skin is improved.

That is, it is desirable to satisfy the following conditional expressions (14) and (15). τ600 / τ550 ≧ 0.8 (14) τ700 / τ550 ≦ 0.08 (15) where τ600 is the transmittance at a wavelength of 600 nm, τ55
0 is the transmittance at the wavelength of 550 nm, τ700 is the wavelength of 700
It is the transmittance in nm. The following conditional expressions (14 ') and (15')
It is even better to meet. τ600 / τ550 ≧ 0.85 (14 ′) τ700 / τ550 ≦ 0.05 (15 ′) Further, it is best to satisfy the following conditional expressions (14 ″) and (15 ″). τ600 / τ550 ≧ 0.9… (14 ") τ700 / τ550 ≦ 0.03… (15")

Another drawback of the solid-state image pickup device such as CCD is that the sensitivity to the wavelength of 550 nm in the near ultraviolet region is considerably higher than that of the human eye. This also highlights the color fringing at the edge of the image due to the chromatic aberration in the near ultraviolet region. In particular, it is fatal to downsize the optical system. Therefore,
Wavelength 550n of transmittance (τ400) at wavelength 400nm
The ratio to the transmittance (τ550) at m is less than 0.08, and the transmittance (τ440) at a wavelength of 440 nm is wavelength 55.
If an absorber or reflector whose ratio to the transmittance (τ550) at 0 nm exceeds 0.4 is inserted in the optical path, the wavelength range necessary for color reproduction is not lost (while maintaining good color reproduction). ) Noise such as color fringing is significantly reduced.

That is, it is desirable that the following conditional expressions (16) and (17) are satisfied. τ400 / τ550 ≦ 0.08 (16) τ440 / τ550 ≧ 0.4 (17) It is more preferable to satisfy the following conditional expressions (16 ′) and (17 ′). τ400 / τ550 ≤ 0.06 (16 ') τ440 / τ550 ≥ 0.5 (17') Further, it is best to satisfy the following conditional expressions (16 ") and (17"). .tau.400 / .tau.550.ltoreq.0.04 (16 ") .tau.440 / .tau.550 .gtoreq.0.6 (17") It should be noted that these filters should be installed between the imaging optical system and the image sensor.

On the other hand, the complementary color filter has substantially higher sensitivity than the CCD with the primary color filter due to its high transmitted light energy and is advantageous in resolution, and therefore, when a small CCD is used. The merit is great.

It should be noted that a better electronic image pickup device can be constructed by appropriately combining the above-mentioned conditional expressions and respective configurations. Further, in each conditional expression, only the upper limit value or only the lower limit value thereof may be limited by the corresponding upper limit value and lower limit value of the more preferable conditional expression. Further, the corresponding values of the conditional expressions described in each of the examples described later may be the upper limit value or the lower limit value.

[0039]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIG. 1 is a sectional view along an optical axis showing an optical configuration according to a first embodiment of a zoom lens used in an electronic image pickup apparatus according to the present invention. It shows the state. FIG. 2 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens according to Example 1 when focused on an object point at infinity. (A) is the wide-angle end, (b) is the middle, and (c) is It shows the state at the telephoto end. 3 to 5 are diagrams showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens according to Example 1 upon focusing on an object point at infinity. FIG. 3 is a wide angle end, and FIG. In the middle, FIG. 5 shows the state at the telephoto end. 6 to 8 are diagrams showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens according to Example 1 upon focusing on a short-distance object point. FIG. 6 is a wide-angle end, and FIG. In the middle, FIG. 8 shows the state at the telephoto end.

As shown in FIG. 1, the electronic image pickup apparatus of the first embodiment has a zoom lens and a CCD which is an electronic image pickup element in order from the object side. In FIG. 1, I is the image pickup surface of the CCD. A flat plate-shaped CCD cover glass CG is provided between the zoom lens and the imaging surface I. The zoom lens includes, in order from the object side, a first lens group G1 and
Aperture stop S, second lens group G2, and third lens group G3
And a fourth lens group G4. First lens group G
Reference numeral 1 denotes, in order from the object side, a front sub-group, a reflective optical element R1 for bending an optical path, and a rear sub-group having a negative refracting power, and has a negative refracting power as a whole. ing. The front side sub unit is composed of a negative meniscus lens L1 ₁ having a convex surface directed toward the object side. The rear subgroup includes, in order from the object side, a biconvex positive lens L1 ₂ and a biconcave negative lens L1 ₃ cemented together, which has a negative refracting power as a whole, and a positive lens having a convex surface directed toward the object side. It is composed of a meniscus lens L1 ₄ . The reflective optical element R1 is configured as a reflective prism that bends the optical path by 90 °. The aspect ratio of the effective image pickup area in each embodiment of the present invention is 3: 4, and the bending direction is the horizontal direction. Second lens group G2
Is composed of, in order from the object side, a cemented lens of a positive meniscus lens L2 ₁ having a convex surface facing the object side and a negative meniscus lens L2 ₂ having a convex surface facing the object side, and a biconvex positive lens L2 _3. , Has a positive refracting power as a whole. The third lens group G3 is composed of a positive meniscus lens L3 ₁ having a convex surface directed toward the object side. The fourth lens group G4 is composed of, in order from the object side, a cemented lens of a biconvex positive lens L4 ₁ and a biconcave negative lens L4 ₂ .

When zooming from the wide-angle end to the telephoto end when focusing on an object point at infinity, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 is an aperture stop. It moves only to the object side together with S, and after the third lens group G3 once widens the distance from the second lens group G2, it moves only to the object side so as to reduce the distance from the second lens group G2. Has become. Further, during the focusing operation, the third lens group G3 moves along the optical axis.
The position of the fourth lens group G4 is fixed even during the focusing operation. The aspherical surface is the image-side surface of the negative meniscus lens L1 ₁ whose convex surface faces the object side in the first lens group G1, and the object of the positive meniscus lens L2 ₁ whose convex surface faces the object side in the second lens group G2. _On the object side of the biconvex positive lens L4 ₁ in the fourth lens group G4.

Next, numerical data of optical members constituting the zoom lens of the first embodiment will be shown. In the numerical data of the first embodiment, r ₁ , r ₂ , ... Are the radii of curvature of each lens surface, d ₁ , d ₂ ,.
_d1 , n _d2 , ... _Are the refractive indices of each lens at the d-line, ν _d1 ,
ν _d2 , ... Is the Abbe number of each lens, Fno. Is the F number, f is the focal length of the entire system, and D0 is the distance from the object to the first surface. The aspherical shape is z in the optical axis direction,
When the direction orthogonal to the optical axis is taken as y, the conical coefficient is K, and the aspherical surface coefficients are A ₄ , A ₆ , A ₈ and A ₁₀ , they are expressed by the following equation. z = (y ² / r) / [1+ {1- (1 + K) (y /
r) ² } ^1/2 ] + A ₄ y ⁴ + A ₆ y ⁶ + A ₈ y ⁸ + A ₁₀ y ¹⁰ These symbols are also common to the numerical data of Examples described later.

Numerical data 1 r ₁ = 69.3459 d ₁ = 0.7000 n _d1 = 1.80610 ν _d1 ＝ 40.92 r ₂ ＝ 4.6083 (aspherical surface) d ₂ = 1.7000 r ₃ ＝ ∞ d ₃ ＝ 6.8000 n _d3 = 1.80610 ν _d3 ＝ 40.92 r ₄ = ∞ d ₄ = 0.1500 r ₅ = 54.8200 d ₅ = 2.2000 n _d5 = 1.71736 v _d5 = 29.52 r ₆ = -8.5000 d ₆ = 0.7000 n _d6 = 1.80610 v _d6 = 40.92 r ₇ = 8.4123 d ₇ = 0.3500 _{8 = 8.8098 d 8 = 1.4000 n} d8 = 1.71736 ν d8 = 29.52 r 9 = 131.4438 d 9 = D9 r 10 = ∞ ( _{stop) d 10 = 0 r 11 =} 3.6905 ( _{aspherical) d 11 = 1.8000 n d11 =} 1.69350 v _d11 = 53.21 r ₁₂ = 6.9000 d ₁₂ = 0.7000 n _d12 = 1.84666 v _d12 = 23.78 r ₁₃ = 3.5205 d ₁₃ = 0.6000 r ₁₄ = 41.4060 d ₁₄ = 1.5000 n _d14 = 1.48749 v _d14 = 70.23 r ₁₅ = -7.8730 _{15 = D15 r 16 = 7.3983 d} 16 = 1.4000 n d16 = 1.48749 ν d16 = 70.23 r 17 = 22.6658 d 17 = D17 r 18 = ∞ ( variable transmittance means or shutter _{Position) d 18 = 4.0000 r 19 =} 8.8186 ( _{aspherical) d 19 = 1.8000 n d19 =} 1.69350 ν d19 = 53.21 r 20 = -6.0000 d 20 = 0.7000 n d20 = 1.84666 ν d20 = 23.78 r 21 = 24.3642 d 21 _{= 0.7000 r 22 = ∞ d 22} = 0.6000 n d22 = 1.51633 ν d22 = 64.14 r 23 = ∞ d 23 = D23 r 24 = ∞ ( imaging plane) d ₂₄ = 0

Second surface of aspherical coefficient K = 0 A ₂ = 0 A ₄ = -1.3839 × 10 ^-3 A ₆ = -4.9944 × 10 ^-6 A ₈ = -3.2538 × 10 ^-6 A ₁₀ = 0 11th surface K = 0 A ₂ = 0 A ₄ = -1.1930 × 10 ^-3 A ₆ = -2.3404 × 10 ^-5 A ₈ = -8.1742 × 10 ^-6 A ₁₀ = 0 19th surface K = 0 A ₂ = 0 A ₄ = -1.3986 x 10 ^-4 A ₆ = -1.5479 x 10 ^-4 A ₈ = 1.5996 x 10 ^-5 A ₁₀ = 0

[0045] Zoom data When D0 (distance from object to first surface) is ∞               Wide-angle end Mid-telephoto end f (mm) 2.50881 4.33366 7.49747 Fno. 2.6859 3.4516 4.5092 D0 ∞ ∞ ∞ D9 11.53831 5.32706 0.89925 D15 1.10008 4.40521 1.29951 D17 1.08630 4.00010 11.52593 D23 1.00000 1.00000 1.00000 When D0 (distance from object to first surface) is short distance (16 cm)               Wide-angle end Mid-telephoto end D0 162.6560 162.6560 162.6560 D9 11.53831 5.32706 0.89925 D15 1.02955 4.22279 0.81871 D17 1.15683 4.18253 12.00672 D23 1.00000 1.00000 1.00000

Second Embodiment FIG. 9 is a sectional view taken along the optical axis showing the optical construction of a second embodiment of the zoom lens used in the electronic image pickup apparatus according to the present invention, which is used when focusing on an object point at infinity at the wide angle end. The state at the time of bending is shown. FIG. 10 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens according to the second example when focusing on an object point at infinity. (A) is the wide-angle end, (b) is the middle, and (c) is It shows the state at the telephoto end. 11 to 13 are diagrams showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens according to Example 2 upon focusing on an object point at infinity.
11 shows a state at the wide-angle end, FIG. 12 shows an intermediate state, and FIG. 13 shows a state at the telephoto end. 14 to 16 are diagrams showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 2 upon focusing on a short-distance object point.
Shows the state at the wide-angle end, FIG. 15 shows the state at the middle, and FIG. 16 shows the state at the telephoto end.

As shown in FIG. 9, the electronic image pickup apparatus of the second embodiment has, in order from the object side, a zoom lens and a CCD which is an electronic image pickup element. In FIG. 9, I is the image pickup surface of the CCD. A flat plate-shaped CCD cover glass CG is provided between the zoom lens and the imaging surface I. The zoom lens includes, in order from the object side, a first lens group G1 and
Aperture stop S, second lens group G2, and third lens group G3
And a fourth lens group G4. First lens group G
Reference numeral 1 denotes, in order from the object side, a front sub-group, a reflective optical element R1 for bending an optical path, and a rear sub-group having a negative refracting power, and has a negative refracting power as a whole. ing. The front side sub unit is composed of a negative meniscus lens L1 ₁ having a convex surface directed toward the object side. The rear sub group includes, in order from the object side, a positive meniscus lens L having a concave surface facing the object side.
1 ₂ ′, a biconcave negative lens L1 ₃ and a positive meniscus lens L1 ₄ having a convex surface facing the object side, which are cemented together and have a negative refracting power as a whole. The reflective optical element R1 is configured as a reflective prism that bends the optical path by 90 °. The aspect ratio of the effective image pickup area in each embodiment of the present invention is 3: 4, and the bending direction is the horizontal direction. The second lens group G2 includes, in order from the object side, a cemented lens of a positive meniscus lens L2 ₁ having a convex surface directed toward the object side and a negative meniscus lens L2 ₂ having a convex surface directed toward the object side, and a biconvex positive lens L2 ₃ . It has a positive refracting power as a whole. The third lens group G3 is composed of a positive meniscus lens L3 ₁ having a convex surface directed toward the object side. The fourth lens group G4 is composed of, in order from the object side, a cemented lens made up of a biconcave negative lens L4 ₁ ′ and a biconvex positive lens L4 ₂ ′.

When zooming from the wide-angle end to the telephoto end when focusing on an object point at infinity, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 is an aperture stop. It moves only to the object side together with S, and after the third lens group G3 once widens the distance from the second lens group G2, it moves only to the object side so as to reduce the distance from the second lens group G2. Has become. Further, during the focusing operation, the third lens group G3 moves along the optical axis.
The position of the fourth lens group G4 is fixed even during the focusing operation. The aspherical surface is the image-side surface of the negative meniscus lens L1 ₁ whose convex surface faces the object side in the first lens group G1, and the object of the positive meniscus lens L2 ₁ whose convex surface faces the object side in the second lens group G2. On the image side of the biconvex positive lens L4 ₂ ′ in the fourth lens group G4.

Next, numerical data of optical members constituting the zoom lens of the second embodiment will be shown. Numerical data 2 r ₁ = 18.1048 d ₁ = 0.7000 n _d1 = 1.80610 ν _d1 ＝ 40.92 r ₂ = 5.9446 (aspherical surface) d ₂ = 1.7000 r ₃ = ∞ d ₃ ＝ 6.8000 n _d3 = 1.80610 ν _d3 ＝ 40.92 r ₄ = ∞ d ₄ = 0.2500 r ₅ = -15.8755 d ₅ = 1.2000 n _d5 = 1.77250 ν _d5 = 49.60 r ₆ = -7.9342 d ₆ = 0.2000 r ₇ = -5.4811 d ₇ = 0.7000 n _d7 = 1.57099 ν _d7 = 50.80 r ₈ = 6.5000 d ₈ = 1.3000 n _d8 = 1.80518 ν _d8 ＝ 25.42 r ₉ ＝ 21.9926 d ₉ ＝ D9 r ₁₀ ＝ ∞ (aperture) d ₁₀ ＝ 0 r ₁₁ ＝ 3.8249 (aspherical surface) d ₁₁ ＝ 1.8000 n _d11 ＝ 1.74320 ν _{d11 = 49.34 r 12 = 8.7000 d} 12 = 0.7000 n d12 = 1.84666 ν d12 = 23.78 r 13 = 3.5665 d 13 = 0.5000 r 14 = 14.6834 d 14 = 1.3000 n d14 = 1.72916 ν d14 = 54.68 r 15 = -14.3114 d 15 _{= D15 r 16 = 7.2299 d 16} = 1.0500 n d16 = 1.48749 ν d16 = 70.23 r 17 = 37.5176 d 17 = 2.0000 r 18 = ∞ d 18 = D18 r 19 = -39.6012 d 19 = 0.7000 n d ₁₉ = 1.84666 ν _d19 ＝ 23.78 r ₂₀ ＝ 10.0000 d ₂₀ = 1.2000 n _d20 = 1.74320 ν _d20 ＝ 49.34 r ₂₁ ＝ -17.1302 (aspherical surface) d ₂₁ ＝ 0.7000 r ₂₂ ＝ ∞ d ₂₂ ＝ 0.6000 n _d22 ＝ 1.51633 ν _d22 = 64.14 r ₂₃ = ∞ d ₂₃ = D 23 r ₂₄ = ∞ (imaging surface) d ₂₄ = 0

Aspherical coefficient 2nd surface K = 0 A ₂ = 0 A ₄ = -2.5409 × 10 ^-4 A ₆ = -1.8273 × 10 ^-5 A ₈ = -3.9239 × 10 ^-7 A ₁₀ = 0 11th surface K = 0 A ₂ = 0 A ₄ = -1.030 3x10 ^-3 A ₆ = -2.50 41x10 ^-5 A ₈ = -5.4268x10 ^-6 A ₁₀ = 0 21st surface K = 0 A ₂ = 0 A ₄ = 7.1492 x 10 ^-4 A ₆ = 3.4398 x 10 ^-4 A ₈ = -3.5902 x 10 ^-5 A ₁₀ = 0

[0051] Zoom data When D0 (distance from object to first surface) is ∞               Wide-angle end Mid-telephoto end f (mm) 3.25250 5.64370 9.74816 Fno. 2.7058 3.4789 4.5017 D0 ∞ ∞ ∞ D9 9.75120 4.59700 0.89810 D15 1.09986 3.92831 1.29837 D18 2.66550 4.99975 11.32016 D23 1.00000 1.00000 1.00000 When D0 (distance from object to first surface) is short distance (16 cm)               Wide-angle end Mid-telephoto end D0 162.6560 162.6560 162.6560 D9 9.75120 4.59700 0.89810 D15 1.01401 3.70564 0.72133 D18 2.75134 5.22242 11.89720 D23 1.00000 1.00000 1.00000

Third Embodiment FIG. 17 is a sectional view taken along the optical axis showing the optical structure of a zoom lens used in an electronic image pickup apparatus according to the third embodiment of the present invention. The state at the time of bending is shown. FIG. 18 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens of Example 3 when focused on an object point at infinity. (A) is the wide-angle end, (b) is the middle, and (c) is It shows the state at the telephoto end. 19 to 21 are diagrams showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens according to Example 3 upon focusing on an object point at infinity. FIG. 19 is a wide angle end, and FIG. In the middle, FIG. 21 shows the state at the telephoto end. 22 to 24 are diagrams showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 3 upon focusing on an object point at a short distance,
22 shows the state at the wide-angle end, FIG. 23 at the middle, and FIG. 24 at the telephoto end.

As shown in FIG. 17, the electronic image pickup apparatus according to the third embodiment has, in order from the object side, a zoom lens and a CCD which is an electronic image pickup element. In FIG. 17, I is CCD
Is the imaging surface of. Between the zoom lens and the imaging surface I,
A flat plate-shaped CCD cover glass CG is provided. The zoom lens includes the first lens group G in order from the object side.
1, the aperture stop S, the second lens group G2, the third lens group G3, and the fourth lens group G4. The first lens group G1 includes, in order from the object side, a front sub-group, a reflective optical element R1 for bending the optical path, and a rear sub-group having a negative refracting power, and has a negative refraction as a whole. Have power The front side sub unit is composed of a negative meniscus lens L1 ₁ having a convex surface directed toward the object side. The rear sub group includes, in order from the object side, a positive meniscus lens L having a concave surface facing the object side.
1 ₂ 'and the biconcave negative lens L1 ₃ are cemented together and have a negative refracting power as a whole, and a positive meniscus lens L1 ₄ having a convex surface facing the object side. The reflective optical element R1 is configured as a reflective prism that bends the optical path by 90 °. The aspect ratio of the effective image pickup area in each embodiment of the present invention is 3: 4, and the bending direction is the horizontal direction. The second lens group G2 includes, in order from the object side, a cemented lens of a positive meniscus lens L2 ₁ having a convex surface directed toward the object side and a negative meniscus lens L2 ₂ having a convex surface directed toward the object side, and a biconvex positive lens L2 ₃ . It has a positive refracting power as a whole. The third lens group G3 is composed of a biconvex positive lens L3 ₁ ′. Fourth lens group G4
Is a cemented lens of, in order from the object side, a negative lens L4 ₁ ″ having a concave surface on the object side and a flat surface on the image side and a positive lens L4 ₂ ″ having a flat surface on the object side and a convex surface on the image side. Has been done.

When zooming from the wide-angle end to the telephoto end when focusing on an object point at infinity, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 is an aperture stop. It moves only to the object side together with S, and after the third lens group G3 once widens the distance from the second lens group G2, it moves only to the object side so as to reduce the distance from the second lens group G2. Has become. Further, during the focusing operation, the third lens group G3 moves along the optical axis.
The position of the fourth lens group G4 is fixed even during the focusing operation. The aspherical surface is the image-side surface of the negative meniscus lens L1 ₁ whose convex surface faces the object side in the first lens group G1, and the object of the positive meniscus lens L2 ₁ whose convex surface faces the object side in the second lens group G2. Positive lens L4 having a flat surface on the object side and a convex surface on the image side in the fourth lens group G4.
It is provided on the image side of ₂ ".

Next, numerical data of optical members constituting the zoom lens of the third embodiment will be shown. Numerical data 3 r ₁ = 10.9287 d ₁ = 0.7000 n _d1 = 1.80610 ν _d1 ＝ 40.92 r ₂ ＝ 4.8122 (aspherical surface) d ₂ ＝ 1.5500 r ₃ ＝ ∞ d ₃ ＝ 6.8000 n _d3 = 1.80610 ν _d3 ＝ 40.92 r ₄ ＝ ∞ d ₄ = 0.1500 r ₅ = -79.5466 d ₅ = 1.3000 n _d5 = 1.75520 v _d5 = 27.51 r ₆ = -6.5000 d ₆ = 0.7000 n _d6 = 1.80610 v _d6 = 40.92 r ₇ = 8.2436 d ₇ = 0.5000 r ₈ = 7.4880 d ₈ = 1.3000 n _d8 = 1.84666 ν _d8 = 23.78 r ₉ = 13.0280 d ₉ = D 9 r ₁₀ = ∞ (aperture) d ₁₀ = 0 r ₁₁ = 3.7669 (aspherical surface) d ₁₁ = 1.8000 n _d11 = 1.74320 ν _d11 = 49.34 r ₁₂ = 8.0000 d ₁₂ = 0.7000 n _d12 = 1.84666 ν _d12 ＝ 23.78 r ₁₃ ＝ 3.3737 d ₁₃ ＝ 0.5000 r ₁₄ ＝ 8.4174 d ₁₄ ＝ 1.5000 n _d14 = 1.72916 ν _d14 ＝ 54.68 r ₁₅ ＝ -28.9216 d ₁₅ ＝ D15 r ₁₆ = 7.6784 d ₁₆ = 1.0500 n _d16 = 1.48749 ν _d16 = 70.23 r ₁₇ = -1722.3948 d ₁₇ = D ₁₇ r ₁₈ = -12.1628 d ₁₈ = 0.7000 n _d18 = 1.84666 ν _d18 = 23.78 r ₁₉ = ∞ d ₁₉ = 1.6000 n _d19 = 1.74320 ν _d19 = 49.34 r ₂₀ = -11.2101 (aspherical surface) d ₂₀ = 0.7000 r ₂₁ = ∞ d ₂₁ = 0.6000 n _d21 = 1.51633 ν _d21 = 64.14 r ₂₂ = ∞ d ₂₂ = D22 r ₂₃ = ∞ (imaging plane) d ₂₃ = 0

Aspheric coefficient 2nd surface K = 0 A ₂ = 0 A ₄ = -3.2755 × 10 ^-5 A ₆ = -3.4477 × 10 ^-5 A ₈ = 9.7425 × 10 ^-8 A ₁₀ = 0 11th surface K = 0 A ₂ = 0 A ₄ = -1.0080 × 10 ^-3 A ₆ = -1.8736 × 10 ^-5 A ₈ = -6.2191 × 10 ^-6 A ₁₀ = 0 20th surface K = 0 A ₂ = 0 A ₄ = 4.2956 x 10 ^-4 A ₆ = 5.2969 x 10 ^-4 A ₈ = -5.4664 x 10 ^-5 A ₁₀ = 0

[0057] Zoom data When D0 (distance from object to first surface) is ∞               Wide-angle end Mid-telephoto end f (mm) 3.25606 5.64124 9.74748 Fno. 2.7505 3.5079 4.5204 D0 ∞ ∞ ∞ D9 9.41588 4.43316 0.89783 D15 1.10006 3.71349 1.29897 D17 4.24487 6.62213 12.56406 D22 1.00000 1.00000 1.00000 When D0 (distance from object to first surface) is short distance (16 cm)               Wide-angle end Mid-telephoto end D0 162.6560 162.6560 162.6560 D9 9.41588 4.43316 0.89783 D15 1.02958 3.53180 0.80556 D17 4.31535 6.80382 13.05747 D22 1.00000 1.00000 1.00000

Next, the values of the parameters of the conditional expressions in the above embodiment are shown in the following table.

In each of the embodiments of the present invention,
As described above, the bending direction is the long side direction (horizontal direction) of the electronic image pickup device (CCD). Bending in the direction of the short side (vertical direction) is more advantageous for miniaturization because it requires less space for folding, but if it is designed to accommodate bending in the direction of the long side, It is preferable because it can be bent to any of the short sides and the degree of freedom in designing a camera incorporating a lens is increased. In each of the above embodiments, the low pass filter is not incorporated, but a low pass filter may be inserted.

Here, the diagonal length L and the pixel spacing a of the effective image pickup surface of the electronic image pickup device will be described. FIG. 25 is a diagram showing an example of a pixel array of the electronic image pickup device used in each embodiment of the present invention, in which R (red), G (green), and B are arranged at pixel intervals a.
Pixels of (blue) or pixels of four colors of cyan, magenta, yellow, and green (green) (FIG. 28) are arranged in a mosaic pattern. The effective image pickup surface means an area in the photoelectric conversion surface on the image pickup element used for reproducing a captured image (display on a personal computer, printing by a printer, etc.). The effective image pickup surface shown in the figure is set in a region narrower than the entire photoelectric conversion surface of the image pickup element in accordance with the performance of the optical system (image circle which can ensure the performance of the optical system). The diagonal length L of the effective image pickup surface is the diagonal length of this effective image pickup surface. In addition,
The image pickup range used for reproducing the image may be variously changed, but when the zoom lens of the present invention is used in an image pickup apparatus having such a function, the diagonal length L of the effective image pickup surface changes. In such a case, the diagonal length L of the effective image pickup surface in the present invention is set to the maximum value in the possible range.

In each of the above-mentioned embodiments, a near-infrared cut filter is provided on the image side of the final lens group, or a near-infrared cut coat is applied to the surface of the CCD cover glass CG on the incident surface side or other lenses. It is applied to the surface on the incident surface side.
Further, no low-pass filter is arranged in the optical path from the incident surface of the zoom lens to the image pickup surface. The near-infrared cut filter and the near-infrared cut coat surface have a transmittance of 80% or more at a wavelength of 60 nm and a transmittance of 1 at a wavelength of 700 nm.
It is configured to be 0% or less. Specifically, for example, it is a multilayer film having the following 27-layer structure.
However, the design wavelength is 780 nm.

Base plate material Physical film thickness (nm) λ / 4 1st layer Al ₂ O ₃ 58.96 0.50 2nd layer TiO ₂ 84.19 1.00 3rd layer SiO ₂ 134.14 1.00 4th layer TiO ₂ 84.19 1.00 5th layer SiO ₂ 134.14 1.00 6th layer TiO ₂ 84.19 1.00 7th layer SiO ₂ 134.14 1.00 8th layer TiO ₂ 84.19 1.00 9th layer SiO ₂ 134.14 1. 00 10th layer TiO ₂ 84.19 1.00 11th layer SiO ₂ 134.14 1.00 12th layer TiO ₂ 84.19 1.00 13th layer SiO ₂ 134.14 1.00 14th layer TiO ₂ 84.19 1.00 15th layer SiO ₂ 178.41 1.33 16th layer TiO ₂ 101.03 1.21 17th layer SiO ₂ 167.67 1.25 18th layer TiO ₂ 96.82 1.15 19th layer SiO ₂ 147.55 1.05 20th layer TiO ₂ 84.19 1.00 21st layer SiO ₂ 160.97 1.20 22nd layer TiO ₂ 84.19 1.00 23rd layer SiO ₂ 154.26 1.15 24th layer TiO ₂ 95.13 1 .13 25th layer SiO ₂ 160.97 1.20 26th layer TiO ₂ 99.34 1.18 27th layer SiO ₂ 87.19 0.65 Aerial

The transmittance characteristics of the above-mentioned near infrared sharp cut coat are as shown in FIG. Also, on the exit surface side of the CCD cover glass CG with the near-infrared cut coat or on the exit surface side of the other lens with the near-infrared cut coat, colors in the short wavelength range as shown in FIG. The color reproducibility of the electronic image is further enhanced by providing a color filter or a coating for reducing the transmission of light. Specifically, with this near infrared cut filter or near infrared cut coating, a wavelength of 400n
The ratio of the transmittance at the wavelength of 420 nm to the transmittance at the wavelength of the highest transmittance at m to 700 nm is 15% or more,
It is preferable that the ratio of the transmittance of the wavelength of 400 nm to the transmittance of the highest wavelength is 6% or less. As a result, it is possible to reduce the deviation between the color of the human eye and the color of the image captured and reproduced. In other words, it is possible to prevent deterioration of the image due to the fact that a color on the short wavelength side, which is hard to be recognized by human eyes, is easily recognized by human eyes.

The transmittance ratio at the wavelength of 400 nm is 6
If it exceeds%, the single-wavelength castle, which is difficult for the human eye to recognize, is regenerated to a recognizable wavelength, and conversely, the above 420
When the ratio of the transmittance of the wavelength of nm is less than 15%, the reproduction of the wavelength castle that can be perceived by humans becomes low, and the color balance becomes poor. Such a means for limiting the wavelength is more effective in the image pickup system using the complementary color mosaic filter.

In each of the above embodiments, as shown in FIG.
0% transmittance at wavelength 400nm, wavelength 420nm
Has a transmittance of 90% and a transmittance peak of 100% at a wavelength of 440 nm. Then, the transmittance of 99% at a wavelength of 450 nm is obtained by multiplying the action with the above-mentioned near infrared sharp cut coat.
With a peak at, the transmittance at a wavelength of 400 nm is 0
%, Transmittance at wavelength 420 nm is 80%, wavelength 60
The transmittance at 0 nm is 82% and the transmittance at a wavelength of 700 nm is 2%. Thereby, more faithful color reproduction is performed.

On the image pickup surface I of the CCD, as shown in FIG. 28, a complementary color mosaic in which four color filters of cyan, magenta, yellow and green (green) are provided in a mosaic pattern corresponding to the image pickup pixels. A filter is provided.
These four types of color filters are arranged in a mosaic pattern so that the numbers of the four types are substantially the same and adjacent pixels do not correspond to the color filters of the same type.
This allows more faithful color reproduction.

The complementary color mosaic filter is specifically
As shown in FIG. 28, at least four types of color filters are included, and the four types of color filters preferably have the following characteristics. Green color filter
G has a spectral intensity peak at a wavelength G _P , yellow color filter Y _e has a spectral intensity peak at a wavelength Y _P , and cyan color filter C has a spectral intensity peak at a wavelength C _P. The magenta color filter M has peaks at wavelengths M _P1 and M _{P 2} and satisfies the following conditional expression. _{510nm <G P <540nm 5nm <} Y P -G P <35nm -100nm <C P -G P <-5nm 430nm <M P1 <480nm 580nm <M P2 <640nm

Further, the green, yellow, and cyan color filters have an intensity of 80% or more at the wavelength of 530 nm with respect to their respective spectral intensity peaks, and the magenta color filter has a wavelength of 530 with respect to their spectral intensity peaks.
It is more preferable to have an intensity of 10% to 50% in nm for improving color reproducibility.

FIG. 29 shows an example of each wavelength characteristic in each of the above embodiments. The green color filter G is
It has a spectral intensity beak at a wavelength of 525 nm. The yellow color filter Y _e has a peak of spectral intensity at a wavelength of 555 nm. The cyan color filter C has a peak of spectral intensity at a wavelength of 510 nm. The magenta color filter M has a wavelength of 445 nm and a wavelength of 620 n.
It has a peak at m. Further, in the respective color filters at the wavelength of 530 nm, G is 99%, Y _e is 95%, C is 97%, and M is 3 with respect to the respective spectral intensity peaks.
It is 8%.

In the case of such a complementary color filter, an unillustrated controller (or a controller used in a digital camera) electrically performs the following signal processing, that is, a luminance signal Y = | G + M + Y _e + C | × 1 / Four color signals R-Y = | (M + Y _e )-(G + C) | BY-== ((M + C)-(G + Y _e ) |), and then R (red), G (green), B (blue) ) Signal is converted. The position of the above-mentioned near infrared sharp cut coat may be any position on the optical path.

Further, in the numerical data of each of the above-mentioned examples, the distance (d ₈ ) from the position of the aperture stop S to the convex surface of the lens on the next image side is 0 is that the vertex of the convex surface of the lens is This means that the position is equal to the intersection of the perpendicular line drawn from the aperture stop S to the optical axis and the optical axis. Although the diaphragm S is a flat plate in each of the above embodiments, a black-painted member having a circular opening may be used as another configuration. Alternatively, a funnel-shaped stop as shown in FIG. 30 may be covered along the inclination of the convex surface of the lens. Furthermore, a diaphragm may be formed in the lens frame that holds the lens.

Further, in each of the above embodiments, the transmittance varying means for adjusting the amount of light and the shutter for adjusting the light receiving time in the present invention are arranged in the air space on the image side of the third lens group G3. Is designed to be able to. As for the light quantity adjusting means, as shown in FIG. 31, a transparent surface or a hollow opening, an ND having a transmittance of 1/2.
A filter, an ND filter having a transmittance of 1/4, and the like provided in a turret shape can be used.

A concrete example of this is shown in FIG. However, in this figure, for convenience, the first lens group G1 to the second lens group G2 are omitted. At the position on the optical axis between the third lens group G3 and the fourth lens group G4, 0 stage, −1 stage, −2 stage,
The turret 10 shown in FIG. 31 that allows the brightness to be adjusted in three stages is arranged. The turret 10 has an aperture having a transmittance of 100%, an ND filter having a transmittance of 50%, an ND filter having a transmittance of 25%, and a transmittance of 12.5 in terms of transmittance for a wavelength of 550 nm in a region that transmits an effective light flux. % Of the ND filters are provided in the openings 1A, 1B, 1C and 1D. Then, by rotating the turret 10 around the rotation axis 11, one of the openings is arranged on the optical axis between the lenses, which is a space different from the aperture position, to adjust the light amount.

Further, as the light quantity adjusting means, as shown in FIG. 33, a filter surface capable of adjusting the light quantity may be provided so as to suppress the unevenness of the light quantity. The filter surface of FIG. 33 is
The transmittances are concentrically different, and the light amount decreases toward the center. Further, by disposing the filter surface, it is possible to give a uniform light transmittance to a dark subject by giving priority to securing the light amount in the central portion, and compensate for uneven brightness only for a bright subject. .

Further, in consideration of thinning of the entire device, an electro-optical element whose transmittance can be electrically controlled can be used. The electro-optical element is, for example, as shown in FIG. 34, a TN liquid crystal cell is sandwiched from both sides by two parallel plates having a transparent electrode and a polarizing film whose polarization direction is aligned with each other.
It can be composed of a liquid crystal filter or the like which changes the polarization direction in the liquid crystal and adjusts the amount of transmitted light by appropriately changing the voltage between the transparent electrodes. In this liquid crystal filter, the voltage applied to the TN liquid crystal cell is adjusted via the variable resistor to change the orientation of the TN liquid crystal cell.

Further, as the light quantity adjusting means, a shutter for adjusting the light receiving time may be provided instead of the various filters for adjusting the transmittance as described above. Alternatively, the shutter may be installed together with the filter. The shutter may be composed of a focal plane shutter with a moving curtain arranged near the image plane, or may be composed of various things such as a two-lens lens shutter provided in the optical path, a focal plane shutter, and a liquid crystal shutter. I do not care.

FIG. 35 is a schematic block diagram showing an example of a rotary focal plane shutter which is one of the focal plane shutters for adjusting the light receiving time applicable to the electronic image pickup apparatus according to each embodiment of the present invention. ) Is a back view, (b) is a front view, and (a) to (d) of FIG. 36 are views of the rotary shutter curtain B as viewed from the image side. In FIG. 35, A is the shutter substrate, B is the rotary shutter curtain, C is the rotary axis of the rotary shutter curtain, and D is
1 and D2 are gears.

In the electronic image pickup apparatus of the present invention, the shutter substrate A is arranged immediately before the image plane or in an arbitrary optical path. Further, the shutter substrate A is provided with an opening A1 that transmits an effective light flux of the optical system. The rotary shutter curtain B is formed in a substantially semicircular shape. The rotary shaft C of the rotary shutter curtain is integrated with the rotary shutter curtain B. Also, the rotation axis C
Rotate with respect to the shutter substrate A. The rotating shaft C is connected to the gears D1 and D2 on the surface of the shutter substrate A. The gears D1 and D2 are connected to a motor (not shown). Then, by driving a motor (not shown), the rotary shutter curtain B is rotated about the rotation axis C through the gears D2, D1 and the rotation axis C in the order shown in FIGS. It has become. The rotary shutter curtain B serves as a shutter by blocking and retracting the opening A1 of the shutter substrate A by rotation. The shutter speed is adjusted by changing the rotating speed of the rotary shutter curtain B.

The light quantity adjusting means has been described above.
In the above-mentioned embodiment of the present invention, these shutters and variable transmittance filters are arranged, for example, on the eighteenth surface of the first and second embodiments. Note that these light amount adjusting means may be arranged at other positions as long as they are different from the above-mentioned aperture stop.

The electro-optical element described above may also serve as a shutter. This is more preferable in terms of reducing the number of parts and downsizing the optical system.

In the electronic image pickup apparatus using the folding zoom lens of the present invention as described above, an object image is formed by an image forming optical system such as a zoom lens and the image is received by an image pickup element such as a CCD or a silver salt film. A shooting device that allows you to shoot
In particular, it can be used for a digital camera, a video camera, a personal computer which is an example of an information processing device, a telephone, and particularly a mobile phone which is convenient to carry. The embodiment will be exemplified below.

FIGS. 37 to 39 are conceptual diagrams of the construction in which the folding zoom lens according to the present invention is incorporated in the photographing optical system 41 of a digital camera, and FIG. 37 is a digital camera 40.
3 is a front perspective view showing the external appearance of FIG.
9 is a cross-sectional view showing the configuration of the digital camera 40. Note that the digital camera shown in FIG. 39 has a configuration in which the imaging optical path is bent in the long side direction of the finder.
The eyes of the observer in Figure 9 are shown from above.

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, and the like. When the shutter 45 arranged on the upper portion of 40 is pressed, the photographing is performed through the photographing optical system 41, for example, the optical path bending zoom lens of the first embodiment in conjunction with the shutter 45. Then, the object image formed by the photographing optical system 41 is formed on the image pickup surface of the CCD 49 through the near infrared cut filter or the near infrared cut coat applied to the CCD cover glass or other lens.

The object image received by the CCD 49 is displayed as an electronic image on the liquid crystal display monitor 47 provided on the rear surface of the camera via the processing means 51. Further, the recording means 52 is connected to the processing means 51, and the captured electronic image can be recorded. Incidentally, this recording means 5
The unit 2 may be provided separately from the processing unit 51, or may be configured to record and write electronically by a floppy (registered trademark) disk, memory card, MO, or the like. Also,
A silver salt camera in which a silver salt film is arranged instead of the CCD 49 may be configured.

Further, a finder objective optical system 53 is arranged on the finder optical path 44. The object image formed by the finder objective optical system 53 is formed on the field frame 57 of the Porro prism 55 which is an image erecting member. Behind the poly prism 55, an eyepiece optical system 59 for guiding an erect image to the observer's eye E is arranged. A cover member 50 is arranged on each of the incident side of the photographing optical system 41 and the objective optical system 53 for the finder, and the exit side of the eyepiece optical system 59.

The digital camera 40 configured as described above
Is effective for thinning the camera by placing and bending the optical path in the long side direction. Further, since the photographic optical system 41 is a zoom lens having a wide angle of view and a high zoom ratio, good aberrations, bright brightness, and a large back focus in which filters and the like can be arranged, high performance and cost reduction can be realized. The image pickup optical path of the digital camera 40 of this embodiment may be bent in the short side direction of the finder. In that case,
The strobe (or the flash) may be arranged further away from the incident surface of the photographing lens so as to have a layout that can mitigate the influence of shadows that occur during stroboscopic photography of a person. Further, in the example of FIG. 39, the plane parallel plate is arranged as the cover member 50, but a lens having power may be used.

Next, FIGS. 40 to 42 show a personal computer as an example of an information processing apparatus in which the folding zoom lens of the present invention is incorporated as an objective optical system. Figure 40 shows a personal computer 30
0 is a front perspective view with the cover open, FIG.
0 is a sectional view of the photographic optical system 303, and FIG. 42 is a side view of FIG.

As shown in FIGS. 40 to 42, the personal computer 3
Reference numeral 00 denotes a keyboard 301 for an operator to input information from the outside, information processing means and recording means (not shown), a monitor 302 for displaying information to the operator, and an image of the operator and surroundings. And an image pickup optical system 303 for Here, the monitor 302 may be a transmissive liquid crystal display element that illuminates from the back side with a backlight (not shown), a reflective liquid crystal display element that reflects and displays light from the front side, a CRT display, or the like. Further, in the figure, the photographing optical system 303 is built in the upper right of the monitor 302, but not limited to that location, it may be anywhere around the monitor 302 or around the keyboard 301.
The photographing optical system 303 has an objective lens 112, which is, for example, an optical path bending zoom lens of the first embodiment according to the present invention, and an image pickup element chip 162 that receives an image, on the photographing optical path 304. These are built in the personal computer 300.

Here, the cover glass CG is additionally attached on the image pickup element chip 162 to attach the image pickup unit 1 to the image pickup unit 1.
The lens frame 1 of the objective lens 112 is integrally formed as 60.
The objective lens 112 and the imaging element chip 1 can be attached by being fitted into the rear end of the lens 13 with one touch.
Since the centering of 62 and the adjustment of the surface spacing are not necessary, the assembly is easy. Further, the tip of the lens frame 113 (not shown)
Is provided with a cover glass 114 for protecting the objective lens 112. The drive mechanism of the zoom lens in the lens frame 113 is not shown.

The object image received by the image pickup device 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. 40 shows an image 305 taken by the operator as an example. Also, this image 305
It is also possible to display it on a personal computer of a communication partner from a remote place via the processing means and the Internet or a telephone.

Next, FIG. 43 shows a telephone which is an example of an information processing apparatus in which the folding zoom lens of the present invention is incorporated as a photographing optical system, particularly a portable telephone which is convenient to carry. 43 (a) is a front view of the mobile phone 400, FIG. 43 (b) is a side view, and FIG. 43 (c) is a cross-sectional view of the photographing optical system 405. As shown in FIGS. 43 (a) to (c), the mobile phone 400 has a microphone unit 401 for inputting the voice of the operator as information, a speaker unit 402 for outputting the voice of the other party of the call, and the operator inputs information. An input dial 403 for inputting, and a monitor 404 for displaying information such as a photographed image of the operator himself / herself or a communication partner and a telephone number.
The image pickup optical system 405, an antenna 406 for transmitting and receiving communication radio waves, and a processing unit (not shown) for processing image information, communication information, input signals, and the like. Here, the monitor 404 is a liquid crystal display element. Further, in the drawing, the arrangement position of each component is not particularly limited to these. The photographing optical system 405 has an objective lens 112, which is disposed on the photographing optical path 407 and includes, for example, the optical path bending zoom lens according to the first embodiment of the present invention, and an image pickup element chip 162 that receives an object image. . These are built into the mobile phone 400.

Here, a cover glass CG is additionally attached on the image pickup element chip 162 so that the image pickup unit 1
The lens frame 1 of the objective lens 112 is integrally formed as 60.
The objective lens 112 and the imaging element chip 1 can be attached by being fitted into the rear end of the lens 13 with one touch.
Since the centering of 62 and the adjustment of the surface spacing are not necessary, the assembly is easy. Further, the tip of the lens frame 113 (not shown)
Is provided with a cover glass 114 for protecting the objective lens 112. The drive mechanism of the zoom lens in the lens frame 113 is not shown.

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

As described above, the zoom lens of the present invention and the electronic image pickup apparatus having the zoom lens have the following characteristics in addition to the invention described in the claims.

(1) The second lens group includes, in order from the object side, a cemented lens component of a positive lens having an aspherical surface and a negative lens, and a positive lens, and satisfies the following conditional expression (2). The zoom lens according to claim 1, wherein 0.7 <R _21R / R _21F <1.6 (2) where R _21R is the radius of curvature on the optical axis of the most image-side surface of the cemented lens component of the second lens group, and R _21F is the second It is the radius of curvature on the optical axis of the surface of the cemented lens component of the lens unit closest to the object side.

(2) The fourth lens group is composed of two lenses, a positive lens and a negative lens, and satisfies the following conditional expression (6). ) The zoom lens described in. 15 <ν _4P −ν _4N (6) where ν _4P is the Abbe number of the positive lens medium of the fourth lens group at the d-line standard, and ν _4N is the d-line reference of the negative lens medium of the fourth lens group. Is the Abbe number in.

(3) The first lens group has, in order from the object side, a front side sub group having a negative lens having a convex surface facing the object side, a reflective optical element for bending the optical path, and a negative refracting power. And a rear subgroup that has the following conditional expression
The zoom lens according to any one of (1) and (2) above, which satisfies (7) and (8). 0.5 <(R _11F + R _11R ) / (R _11F −R _11R ) <5.0 (7) 0 <f ₁₁ / f ₁₂ <1.2 (8) where R _11F is the first lens group. R _11R is the radius of curvature on the optical axis of the object side surface of the negative lens of the front side subgroup of, and R _11R is the radius of curvature of the image side surface of the negative lens of the front side subgroup of the first lens group,
f ₁₁ is the focal length of the front sub-group of the first lens group, and f ₁₂ is the focal length of the rear sub-group of the first lens group.

(4) The front subgroup is composed of one negative lens having an aspherical surface, and the rear subgroup is composed of two lens components having different refraction power signs. ) Is satisfied, the above (1),
The zoom lens according to any one of (2). 0.4 <(R _12R / R _13F ) ^P <1.6 (9) where R _12R is the object side surface of the air lens formed between the two lens components of the rear subgroup of the first lens group. The radius of curvature on the optical axis, R _13F is the radius of curvature on the optical axis of the image side surface of the air lens formed between the two lens components of the rear sub-group of the first lens group, and P is 2 The order of the lens components from the object side is P = 1 when the negative lens component and the positive lens component are arranged in this order, and P = −1 when the positive lens component and the negative lens component are arranged in this order. To do.

(5) An electronic image pickup apparatus comprising the zoom lens according to any one of (1) and (2) above, and an electronic image pickup element arranged on the image side thereof.

(6) The first lens group has, in order from the object side, a front side sub group having a negative lens having a convex surface facing the object side, a reflective optical element for bending the optical path, and a negative refracting power. And a rear subgroup that has the following conditional expression
Satisfying (7) and (8), the second lens group is composed of, in order from the object side, a cemented lens component of a positive lens and a negative lens having an aspherical surface, and a positive lens. An electronic image pickup apparatus comprising: the zoom lens according to claim 1 satisfying the condition (2); and an electronic image pickup element arranged on the image side thereof. 0.5 <(R _11F + R _11R ) / (R _11F -R _11R ) <5.0 (7) 0 <f ₁₁ / f ₁₂ <1.2 (8) 0.7 <R _21R / R _21F <1.6 (2) where R _11F is the radius of curvature on the optical axis of the object side surface of the negative lens in the front subgroup of the first lens group, and R _11R is the front subgroup of the first lens group. Radius of curvature on the optical axis of the image-side surface of the negative lens,
f ₁₁ is the focal length of the front sub-group of the first lens group, f ₁₂ is the focal length of the rear sub-group of the first lens group, R _21R is the light on the most image-side surface of the cemented lens component of the second lens group Radius of curvature on axis,
R _21F is the radius of curvature on the optical axis of the surface of the cemented lens component of the second lens unit closest to the object side.

(7) The first lens group has, in order from the object side, a front subgroup having a negative lens having a convex surface directed toward the object side, a reflective optical element for bending the optical path, and a negative refractive power. And a rear subgroup that has the following conditional expression
The zoom according to claim 1, wherein (7) and (8) are satisfied, the fourth lens group is composed of two lenses, a positive lens and a negative lens, and the following conditional expression (6) is satisfied. An electronic image pickup apparatus comprising a lens and an electronic image pickup element arranged on the image side thereof. 0.5 <(R _11F + R _11R ) / (R _11F −R _11R ) <5.0 (7) 0 <f ₁₁ / f ₁₂ <1.2 (8) 15 <ν _4P −ν _4N … ( 6) where R _11F is the radius of curvature on the optical axis of the object side surface of the negative lens in the front subgroup of the first lens group, and R _11R is the image side of the negative lens in the front subgroup of the first lens group. Radius of curvature of the surface on the optical axis,
f ₁₁ is the focal length of the front sub-group of the first lens group, f ₁₂ is the focal length of the rear sub-group of the first lens group, and ν _4P is the Abbe of the positive lens medium of the fourth lens group at the d-line standard. The number, ν _4N, is the Abbe number on the d-line basis of the medium of the negative lens of the fourth lens group.

(8) The first lens group has, in order from the object side, a front side sub group having a negative lens having a convex surface facing the object side, a reflective optical element for bending the optical path, and a negative refracting power. And a rear subgroup that has the following conditional expression
Satisfying (7) and (8), the second lens group is composed of, in order from the object side, a cemented lens component of a positive lens and a negative lens having an aspherical surface, and a positive lens. The zoom lens according to claim 1, wherein (4) is satisfied, the fourth lens group is composed of two lenses, a positive lens and a negative lens, and the following conditional expression (6) is satisfied: An electronic image pickup device comprising: an electronic image pickup device arranged on the image side. 0.5 <(R _11F + R _11R ) / (R _11F -R _11R ) <5.0 (7) 0 <f ₁₁ / f ₁₂ <1.2 (8) 0.7 <R _21R / R _21F <1.6 (2) 15 <ν _4P −ν _4N (6) where R _11F is the radius of curvature on the optical axis of the object side surface of the negative lens in the front subgroup of the first lens group, R _11R is the radius of curvature on the optical axis of the image side surface of the negative lens of the front subgroup of the first lens group,
f ₁₁ is the focal length of the front sub-group of the first lens group, f ₁₂ is the focal length of the rear sub-group of the first lens group, R _21R is the light on the most image-side surface of the cemented lens component of the second lens group Radius of curvature on axis,
R _21F is the radius of curvature on the optical axis of the most object-side surface of the cemented lens component of the second lens group, ν _4P is the Abbe number of the positive lens medium of the fourth lens group on the d-line basis, and ν _4N is It is the Abbe number on the d-line basis of the medium of the negative lens of the fourth lens group.

(9) The first lens group has, in order from the object side, a front side sub group having a negative lens having a convex surface facing the object side, a reflective optical element for bending the optical path, and a negative refracting power. And a rear subgroup that has the following conditional expression
(7) and (8) are satisfied, the front side sub group is composed of a negative lens having one aspherical surface, and the rear side sub group is composed of two lens components having different signs of refractive power. Conditional expression (9) is satisfied, the second lens group is composed of, in order from the object side, a cemented lens component of a positive lens and a negative lens having an aspherical surface, and a positive lens. An electronic image pickup apparatus comprising: the zoom lens according to claim 1 which satisfies 2); and an electronic image pickup element arranged on the image side thereof. 0.5 <(R _11F + R _11R ) / (R _11F −R _11R ) <5.0 (7) 0 <f ₁₁ / f ₁₂ <1.2 (8) 0.4 <(R _12R / R _13F ) ^P <1.6 (9) 0.7 <R _21R / R _21F <1.6 (2) where R _11F is the object side surface of the negative lens in the front subgroup of the first lens group. The radius of curvature on the optical axis, R _11R is the radius of curvature on the optical axis of the image side surface of the negative lens of the front sub-group of the first lens group,
f ₁₁ is the focal length of the front subgroup of the first lens group, f ₁₂ is the focal length of the rear subgroup of the first lens group, and R _12R is between the two lens components of the rear subgroup of the first lens group. The radius of curvature of the object side surface of the formed air lens on the optical axis, R _13F is the optical axis of the image side surface of the air lens formed between the two lens components of the rear subgroup of the first lens group. Is a radius of curvature, and P is P = 1 when the order of the two lens components from the object side is the negative lens component and the positive lens component, and P is the positive lens component and the negative lens component. If so, P = -1. R _21R is the radius of curvature of the most image-side surface of the cemented lens component of the second lens group on the optical axis, and R _21F is the curvature of the most object-side surface of the cemented lens component of the second lens group on the optical axis. Is the radius.

(10) The first lens group has, in order from the object side, a front side sub group having a negative lens with a convex surface facing the object side, a reflective optical element for bending the optical path, and a negative refractive power. And a rear subgroup that has the following conditional expression
(7), (8) is satisfied, the front side sub-group is composed of a negative lens having one aspherical surface, the rear side sub-group is composed of two lens components having different signs of refractive power, 2. The zoom lens according to claim 1, wherein the conditional expression (9) is satisfied, the fourth lens group is composed of two lenses, a positive lens and a negative lens, and the following conditional expression (6) is satisfied. And an electronic image pickup device including an electronic image pickup element arranged on the image side. 0.5 <(R _11F + R _11R ) / (R _11F −R _11R ) <5.0 (7) 0 <f ₁₁ / f ₁₂ <1.2 (8) 0.4 <(R _12R / R _13F ) ^P <1.6 (9) 15 <ν _4P −ν _4N (6) where R _11F is the curvature of the object side surface of the negative lens in the front subgroup of the first lens group on the optical axis. Radius, R _11R is the radius of curvature on the optical axis of the image-side surface of the negative lens of the front sub-group of the first lens group,
f ₁₁ is the focal length of the front subgroup of the first lens group, f ₁₂ is the focal length of the rear subgroup of the first lens group, and R _12R is between the two lens components of the rear subgroup of the first lens group. The radius of curvature of the object side surface of the formed air lens on the optical axis, R _13F is the optical axis of the image side surface of the air lens formed between the two lens components of the rear subgroup of the first lens group. Is a radius of curvature, and P is P = 1 when the order of the two lens components from the object side is the negative lens component and the positive lens component, and P is the positive lens component and the negative lens component. If so, P = -1. ν _4P is the Abbe number of the positive lens medium of the fourth lens group with respect to the d-line, and ν _4N is the negative lens medium d of the fourth lens group.
Abbe number on a line basis.

(11) The first lens group has, in order from the object side, a front sub-group having a negative lens with a convex surface facing the object side, a reflective optical element for bending the optical path, and a negative refractive power. And a rear subgroup that has the following conditional expression
(7), (8) is satisfied, the front side sub-group is composed of a negative lens having one aspherical surface, the rear side sub-group is composed of two lens components having different signs of refractive power, Conditional expression (9) is satisfied, the second lens group is composed of, in order from the object side, a cemented lens component of a positive lens and a negative lens having an aspherical surface, and a positive lens. 2. The zoom lens according to claim 1, wherein the second lens group satisfies 2), the fourth lens group is composed of two lenses, a positive lens and a negative lens, and the following conditional expression (6) is satisfied: An electronic image pickup device including an electronic image pickup device disposed on the side. 0.5 <(R _11F + R _11R ) / (R _11F -R _11R ) <5.0 (7) 0 <f ₁₁ / f ₁₂ <1.2 (8) 0.4 <(R _12R / R _13F ) ^P <1.6 (9) 0.7 <R _21R / R _21F <1.6 (2) 15 <ν _4P −ν _4N (6) However, R _11F is the front side of the first lens group. The radius of curvature on the optical axis of the object side surface of the negative lens of the sub group, R _11R is the radius of curvature of the image side surface of the negative lens of the front side sub group of the first lens group on the optical axis,
f ₁₁ is the focal length of the front subgroup of the first lens group, f ₁₂ is the focal length of the rear subgroup of the first lens group, and R _12R is between the two lens components of the rear subgroup of the first lens group. The radius of curvature of the object side surface of the formed air lens on the optical axis, R _13F is the optical axis of the image side surface of the air lens formed between the two lens components of the rear subgroup of the first lens group. Is a radius of curvature, and P is P = 1 when the order of the two lens components from the object side is the negative lens component and the positive lens component, and P is the positive lens component and the negative lens component. If so, P = -1. R _21R is the radius of curvature of the most image-side surface of the cemented lens component of the second lens group on the optical axis, and R _21F is the curvature of the most object-side surface of the cemented lens component of the second lens group on the optical axis. radius,
ν _4P is the Abbe number of the positive lens medium of the fourth lens group with respect to the d-line, and ν _4N is the Abbe number of the negative lens medium of the fourth lens group with respect to the d line.

(12) The second lens group is composed of, in order from the object side, a cemented lens component of a positive lens having an aspherical surface and a negative lens, and a positive lens, and satisfies the following conditional expression (2). Then, if any cemented surface included in the cemented lens component of the second lens group and the medium of the lens on both sides thereof satisfy the following conditional expression:
The zoom lens according to claim 1, which satisfies (3) and (4),
An electronic image pickup device comprising an electronic image pickup device arranged on the image side. 0.7 <R _21R / R _21F <1.6 (2) 0 <L / R _21C <1.4 (3) 15 <ν _21F −ν _21R (4) where R _21R is the second lens The radius of curvature of the most image-side surface of the cemented lens component of the group on the optical axis, R _21F is the radius of curvature of the most object side surface of the cemented lens component of the second lens group on the optical axis, and L is electronic imaging. Diagonal length of effective imaging area of device, R _21C
Is the radius of curvature of the cemented surface in the second lens group on the optical axis,
ν _21F is the Abbe number of the medium of the lens on the object side of the cemented surface in the second lens group based on the d-line, and ν _21R is the d-line of the medium of the lens on the image side of the cemented surface in the second lens group. Is the Abbe number.

(13) The second lens group has a cemented component, and one of the cemented surfaces included in the cemented lens component and the medium of the lens on both sides thereof satisfy the following conditional expressions (3) and (4). 2. The zoom lens according to claim 1, wherein the fourth lens group is composed of two lenses, a positive lens and a negative lens, and satisfies the following conditional expression (6). Electronic image pickup device including the electronic image pickup device. 0 <L / R _21C <1.4 (3) 15 <ν _21F −ν _21R (4) 15 <ν _4P −ν _4N (6) where L is the diagonal of the effective image pickup area of the electronic image pickup device. Long, R
_21C is the radius of curvature of the cemented surface in the second lens group on the optical axis, ν _21F is the Abbe number of the medium of the lens on the object side of the cemented surface in the second lens group based on the d-line, and ν _21R is the second Abbe number of the medium of the lens on the image side of the cemented surface in the lens group based on the d-line, ν _4P is the Abbe number of the medium of the positive lens of the fourth lens group based on the d-line, and ν _4N is the fourth lens group Of the negative lens medium d
Abbe number on a line basis.

(14) The second lens group is composed of, in order from the object side, a cemented lens component of a positive lens having an aspherical surface and a negative lens, and a positive lens, and satisfies the following conditional expression (2). Then, if any cemented surface included in the cemented lens component of the second lens group and the medium of the lens on both sides thereof satisfy the following conditional expression:
The zoom according to claim 1, wherein (3) and (4) are satisfied, the fourth lens group is composed of two lenses, a positive lens and a negative lens, and the following conditional expression (6) is satisfied. An electronic image pickup apparatus comprising a lens and an electronic image pickup element arranged on the image side thereof. 0.7 <R _21R / R _21F <1.6 (2) 0 <L / R _21C <1.4 (3) 15 <ν _21F -ν _21R ... (4) 15 <ν _4P -ν _4N ... (6) where R _21R is the radius of curvature on the optical axis of the most image-side surface of the cemented lens component of the second lens group, and R _21F is the light of the most object-side surface of the cemented lens component of the second lens group. The radius of curvature on the axis, L is the diagonal length of the effective image pickup area of the electronic image pickup device, R _21C
Is the radius of curvature of the cemented surface in the second lens group on the optical axis,
ν _21F is the Abbe number of the medium of the lens on the object side of the cemented surface in the second lens group based on the d-line, and ν _21R is the d-line of the medium of the lens on the image side of the cemented surface in the second lens group. Abbe number of
ν _4P is the Abbe number of the positive lens medium of the fourth lens group with respect to the d-line, and ν _4N is the Abbe number of the negative lens medium of the fourth lens group with respect to the d line.

(15) The first lens group has, in order from the object side, a front side sub group having a negative lens having a convex surface facing the object side, a reflective optical element for bending the optical path, and a negative refracting power. And a rear subgroup that has the following conditional expression
Satisfying (7) and (8), the second lens group is composed of, in order from the object side, a cemented lens component of a positive lens and a negative lens having an aspherical surface, and a positive lens. (2) is satisfied, and one of the cemented surfaces included in the cemented lens component of the second lens group and the medium of the lenses on both sides thereof satisfy the following conditional expression:
The zoom lens according to claim 1, which satisfies (3) and (4),
An electronic image pickup device comprising an electronic image pickup device arranged on the image side. 0.5 <(R _11F + R _11R ) / (R _11F -R _11R ) <5.0 (7) 0 <f ₁₁ / f ₁₂ <1.2 (8) 0.7 <R _21R / R _21F <1.6 (2) 0 <L / R _21C <1.4 (3) 15 <ν _21F −ν _21R (4) where R _11F is the negative lens of the front subgroup of the first lens group. R _11R is the radius of curvature of the object-side surface on the optical axis, and R _11R is the radius of curvature of the image-side surface of the negative lens of the front sub-group of the first lens group on the optical axis,
f ₁₁ is the focal length of the front sub-group of the first lens group, f ₁₂ is the focal length of the rear sub-group of the first lens group, R _21R is the light on the most image-side surface of the cemented lens component of the second lens group Radius of curvature on axis,
R _21F is the radius of curvature on the optical axis of the most object-side surface of the cemented lens component of the second lens group, L is the diagonal length of the effective image pickup area of the electronic image sensor, and R _21C is the cemented lens in the second lens group. The radius of curvature on the optical axis of the surface, ν _21F is the Abbe number of the medium of the lens on the object side of the cemented surface in the second lens group, which is based on the d-line, ν
_21R is the Abbe number on the d-line basis of the medium of the lens on the image side of the cemented surface in the second lens group.

(16) The first lens group has, in order from the object side, a front side sub group having a negative lens having a convex surface facing the object side, a reflective optical element for bending the optical path, and a negative refractive power. And a rear subgroup that has the following conditional expression
(7) and (8) are satisfied, and one of the cemented surfaces included in the cemented lens component of the second lens group and the media of the lenses on both sides thereof satisfy the following conditional expressions (3) and (4): The zoom lens according to claim 1, wherein the fourth lens group includes two lenses, a positive lens and a negative lens, and satisfies the following conditional expression (6):
An electronic image pickup device comprising an electronic image pickup device arranged on the image side. 0.5 <(R _11F + R _11R ) / (R _11F −R _11R ) <5.0 (7) 0 <f ₁₁ / f ₁₂ <1.2 (8) 0 <L / R _21C <1. 4 (3) 15 <ν _21F −ν _21R … (4) 15 <ν _4P −ν _4N … (6) where R _11F is the light on the object side surface of the negative lens in the front subgroup of the first lens group. The radius of curvature on the axis, R _11R is the radius of curvature on the optical axis of the image side surface of the negative lens of the front subgroup of the first lens group,
f ₁₁ is the focal length of the front subgroup of the first lens group, f ₁₂ is the focal length of the rear subgroup of the first lens group, L is the diagonal length of the effective image pickup area of the electronic image pickup device, and R _21C is the second The radius of curvature of the cemented surface in the lens group on the optical axis, ν _21F is the Abbe number of the medium of the lens on the object side of the cemented surface in the second lens group based on the d-line,
ν _21R is the Abbe number of the medium of the lens on the image side of the cemented surface in the second lens group with respect to the d-line, ν _4P is the Abbe number of the medium of the positive lens of the fourth lens group with respect to the d-line, ν _4N Is the Abbe number on the d-line basis of the medium of the negative lens of the fourth lens group.

(17) The first lens group has, in order from the object side, a front sub-group having a negative lens having a convex surface facing the object side, a reflective optical element for bending the optical path, and a negative refracting power. And a rear subgroup that has the following conditional expression
Satisfying (7) and (8), the second lens group is composed of, in order from the object side, a cemented lens component of a positive lens and a negative lens having an aspherical surface, and a positive lens. (2) is satisfied, and one of the cemented surfaces included in the cemented lens component of the second lens group and the medium of the lenses on both sides thereof satisfy the following conditional expression:
The zoom according to claim 1, wherein (3) and (4) are satisfied, the fourth lens group is composed of two lenses, a positive lens and a negative lens, and the following conditional expression (6) is satisfied. An electronic image pickup apparatus comprising a lens and an electronic image pickup element arranged on the image side thereof. 0.5 <(R _11F + R _11R ) / (R _11F −R _11R ) <5.0 (7) 0 <f ₁₁ / f ₁₂ <1.2 (8) 0.7 <R _21R / R _21F <1.6… (2) 0 <L / R _21C <1.4… (3) 15 <ν _21F −ν _21R … (4) 15 <ν _4P −ν _4N … (6) However, R _11F is the first The radius of curvature on the optical axis of the object side surface of the negative lens of the front subgroup of the first lens group, R _11R is the curvature of the image side surface of the negative lens of the front subgroup of the first lens group on the optical axis radius,
f ₁₁ is the focal length of the front sub-group of the first lens group, f ₁₂ is the focal length of the rear sub-group of the first lens group, R _21R is the light on the most image-side surface of the cemented lens component of the second lens group Radius of curvature on axis,
R _21F is the radius of curvature on the optical axis of the most object-side surface of the cemented lens component of the second lens group, L is the diagonal length of the effective image pickup area of the electronic image sensor, and R _21C is the cemented lens in the second lens group. The radius of curvature on the optical axis of the surface, ν _21F is the Abbe number of the medium of the lens on the object side of the cemented surface in the second lens group, which is based on the d-line, ν
_21R is the Abbe number of the medium of the lens on the image side of the cemented surface in the second lens group with respect to the d-line, ν _4P is the Abbe number of the medium of the positive lens of the fourth lens group with respect to the d-line, and ν _4N is It is the Abbe number on the d-line basis of the medium of the negative lens of the fourth lens group.

(18) The first lens group is from the object side.
In order, the front subgroup having a negative lens with the convex surface facing the object side
And a reflective optical element for bending the optical path,
It is composed of a rear subgroup having refractive power, and the following conditional expression
Satisfies (7) and (8), and the front side subgroup has one aspherical surface.
The rear subgroup has a sign of refractive power.
Comprised of two different lens components, the following conditional expression (9)
Satisfied, the second lens group, in order from the object side, aspherical surface
Having a cemented lens component of a positive lens and a negative lens having
A lens and satisfies the following conditional expression (2),
Any cemented surface included in the cemented lens component of the two lens groups
And the media of the lenses on both sides satisfy the following conditional expressions (3) and (4).
The zoom lens according to claim 1, which is disposed on the image side.
Electronic image pickup device including the electronic image pickup device.       0.5 <(R_11F+ R_11R) / (R_11F-R_11R) <5.0 (7)       0 <f₁₁/ F₁₂  <1.2 (8)       0.4 <(R_12R/ R_13F)^P  <1.6 (9)       0.7 <R_21R/ R_21F  <1.6 (2)       0 <L / R_21C  <1.4 (3)       15 <ν_21F−ν_21R                                     …(Four) However, R_11FIs the negative lens of the front subgroup of the first lens group
Radius of curvature on the optical axis of the body side surface, R_11RIs in the first lens group
The radius of curvature on the optical axis of the image-side surface of the negative lens in the front sub-group,
f₁₁Is the focal length of the front subgroup of the first lens group, f₁₂Is the first
Focal length of rear subgroup of lens group, R_12RIs the first lens group
Air lens formed between two lens components of the rear subgroup
Radius of curvature of the object side surface on the optical axis, R_13FIs the first lens
The air lens formed between the two lens components of the rear subgroup of the group.
Is the radius of curvature of the image side of the lens on the optical axis, and P is 2
The order from the object side of the lens component is the negative lens component and the positive lens component.
If the lens components are arranged in this order, set P = 1 and make a positive lens.
If the minute and the negative lens components are arranged in this order, P = -1.
It R_21RIs the most image side of the cemented lens component of the second lens group
Radius of curvature on the optical axis of the surface of R_21FIs the contact of the second lens group
Radius of curvature of the surface of the compound lens component closest to the object on the optical axis,
L is the diagonal length of the effective image pickup area of the electronic image pickup device, R _21CIs the
The radius of curvature on the optical axis of the cemented surface in the two lens groups, ν
_21FIs the medium of the lens on the object side of the cemented surface in the second lens group.
Abbe number on the d-line standard, ν_21RIs the contact in the second lens group
Abbe number based on d-line of the medium of the lens on the image side of the mating surface
It

(19) The first lens group has, in order from the object side, a front side sub group having a negative lens having a convex surface facing the object side, a reflective optical element for bending the optical path, and a negative refracting power. And a rear subgroup that has the following conditional expression
(7) and (8) are satisfied, the front side sub group is composed of a negative lens having one aspherical surface, and the rear side sub group is composed of two lens components having different signs of refractive power. Conditional expression (9) is satisfied, the second lens group has a cemented lens component, and any cemented surface included in the cemented lens component and the medium of the lenses on both sides thereof satisfy the following conditional expression (3). , (4), the fourth
The zoom lens according to claim 1, wherein the lens group is composed of two lenses, a positive lens and a negative lens, and the following conditional expression (6) is satisfied, and an electronic image pickup element arranged on the image side thereof: An electronic image pickup apparatus including. 0.5 <(R _11F + R _11R ) / (R _11F -R _11R ) <5.0 (7) 0 <f ₁₁ / f ₁₂ <1.2 (8) 0.4 <(R _12R / R _13F ) ^P <1.6 (9) 0 <L / R _21C <1.4 (3) 15 <ν _21F −ν _21R … (4) 15 <ν _4P −ν _4N … (6) However, R _11F is the radius of curvature on the optical axis of the object side surface of the negative lens of the front subgroup of the first lens group, and R _11R is the optical axis of the image side surface of the negative lens of the front subgroup of the first lens group. Radius of curvature at,
f ₁₁ is the focal length of the front subgroup of the first lens group, f ₁₂ is the focal length of the rear subgroup of the first lens group, and R _12R is between the two lens components of the rear subgroup of the first lens group. The radius of curvature of the object side surface of the formed air lens on the optical axis, R _13F is the optical axis of the image side surface of the air lens formed between the two lens components of the rear subgroup of the first lens group. Is a radius of curvature, and P is P = 1 when the order of the two lens components from the object side is the negative lens component and the positive lens component, and P is the positive lens component and the negative lens component. If so, P = -1. L is the diagonal length of the effective image pickup area of the electronic image pickup device, R _{21 C}
Is the radius of curvature of the cemented surface in the second lens group on the optical axis,
ν _21F is the Abbe number of the medium of the lens on the object side of the cemented surface in the second lens group based on the d-line, and ν _21R is the d-line of the medium of the lens on the image side of the cemented surface in the second lens group. Abbe number of
ν _4P is the Abbe number of the positive lens medium of the fourth lens group with respect to the d-line, and ν _4N is the Abbe number of the negative lens medium of the fourth lens group with respect to the d line.

(20) The first lens group is from the object side.
In order, the front subgroup having a negative lens with the convex surface facing the object side
And a reflective optical element for bending the optical path,
It is composed of a rear subgroup having refractive power, and the following conditional expression
Satisfies (7) and (8), and the front side subgroup has one aspherical surface.
The rear subgroup has a sign of refractive power.
Comprised of two different lens components, the following conditional expression (9)
Satisfied, the second lens group, in order from the object side, aspherical surface
Having a cemented lens component of a positive lens and a negative lens having
A lens and satisfies the following conditional expression (2),
Any cement included in the cemented lens component of the two lens groups
The medium of the surface and the lenses on both sides satisfy the following conditional expressions (3) and (4).
The fourth lens group includes a positive lens and a negative lens.
Claim consisting of one lens and satisfying the following conditional expression (6)
The zoom lens according to Item 1 and an electric power arranged on the image side.
An electronic image pickup device including a child image pickup element.       0.5 <(R_11F+ R_11R) / (R_11F-R_11R) <5.0 (7)       0 <f₁₁/ F₁₂  <1.2 (8)       0.4 <(R_12R/ R_13F)^P  <1.6 (9)       0.7 <R_21R/ R_21F  <1.6 (2)       0 <L / R_21C  <1.4 (3)       15 <ν_21F−ν_21R                                     …(Four)       15 <ν_4P−ν_4N                                       … (6) However, R_11FIs the negative lens of the front subgroup of the first lens group
Radius of curvature on the optical axis of the body side surface, R_11RIs in the first lens group
The radius of curvature on the optical axis of the image-side surface of the negative lens in the front sub-group,
f₁₁Is the focal length of the front subgroup of the first lens group, f₁₂Is the first
Focal length of rear subgroup of lens group, R_12RIs the first lens group
Air lens formed between two lens components of the rear subgroup
Radius of curvature of the object side surface on the optical axis, R_13FIs the first lens
The air lens formed between the two lens components of the rear subgroup of the group.
Is the radius of curvature of the image side of the lens on the optical axis, and P is 2
The order from the object side of the lens component is the negative lens component and the positive lens component.
If the lens components are arranged in this order, set P = 1 and make a positive lens.
If the minute and the negative lens components are arranged in this order, P = -1.
It R_21RIs the most image side of the cemented lens component of the second lens group
Radius of curvature on the optical axis of the surface of R_21FIs the contact of the second lens group
Radius of curvature of the surface of the compound lens component closest to the object on the optical axis,
L is the diagonal length of the effective image pickup area of the electronic image pickup device, R _21CIs the
The radius of curvature on the optical axis of the cemented surface in the two lens groups, ν
_21FIs the medium of the lens on the object side of the cemented surface in the second lens group.
Abbe number on the d-line standard, ν_21RIs the contact in the second lens group
Abbe number on the d-line basis of the medium of the lens on the image side of the mating surface, ν
_4PIs the positive lens medium of the fourth lens group, which is based on the d-line.
Base number, ν_4NIs the d-line reference of the medium of the negative lens of the fourth lens group
Is the Abbe number in.

(21) 2 of the rear sub-group of the first lens group
At least one of the two lens components is composed of a cemented lens component in which a positive lens and a negative lens are cemented, and the following conditional expressions (10) and (11) are satisfied: The electronic imaging device according to any one of 3 to 5. 3 <ν _A2N −ν _A2P <40 (10) 0.2 <Q · L / R _A2C <1.0 (11) where ν _A2N is a cemented lens component in the rear subgroup of the first lens group. _Is the Abbe number of the medium of the negative lens in the d-line standard, ν _A2P is the Abbe number of the medium of the positive lens of the cemented lens component in the rear subgroup of the first lens group in the d-line standard,
L is the diagonal length of the effective image pickup area of the electronic image pickup device, and R _A2C is the radius of curvature on the optical axis of the cemented surface of the cemented lens component in the rear subgroup of the first lens group. Q is Q = 1 when the cemented lens component in the rear subgroup of the first lens unit is a negative lens and a positive lens in order from the object side, and is Q = 1 when the lens is a positive lens from the object side and a negative lens To do.

(22) The fourth lens group has the following conditional expression:
The electronic imaging device according to any one of claims 3 to 6 and (5) to (21), which satisfies (5). −0.4 <L / fD <0.6 (5) where L is the diagonal length of the effective image pickup area of the electronic image pickup device, and f
D is the focal length of the fourth lens group.

(23) The zoom lens according to any one of (1) to (4) above, wherein the third lens group moves on the optical axis during the focusing operation.

(24) The fourth lens group is fixed during zooming and focusing.
2. The zoom lens according to any one of (1) to (4) and (23) above.

(25) When the horizontal pixel pitch of the electronic image pickup device is a and the open F value at the wide-angle end of the zoom lens is F, the following conditional expression (12) is satisfied. The electronic imaging device according to any one of claims 3 to 6 and (5) to (22). F ≧ a / (1 μm) (12)

(26) The inner diameter of the aperture stop that determines the open F value is fixed, and a lens having a convex surface facing the stop is provided immediately before or after the stop, and the optical axis and the aperture stop The electronic image pickup device according to (25), characterized in that an intersection with a perpendicular drawn to the optical axis is located within the lens or within 0.5 mm from a surface vertex of the convex surface.

(27) A transmittance varying means for adjusting the amount of light guided to the electronic image pickup device by changing the transmittance is provided, and the transmittance varying means is an optical path in a space different from the space in which the diaphragm is arranged. The electronic imaging device according to (26) above, which is disposed inside.

(28) A shutter is provided for adjusting a light receiving time of a light beam guided to the electronic image pickup device, and the shutter is arranged in an optical path of a space different from a space in which the diaphragm is arranged. The electronic image pickup device according to (26) or (27).

(29) The electronic image pickup device according to any one of the above (25) to (28), wherein a low-pass filter is not arranged in the optical path from the incident surface of the optical system to the image pickup surface.

(30) The zoom lens according to any one of claims 1 and 2 and (1) to (4), characterized by satisfying the following conditional expression (13). 1.8 <fT / fw (13) where fT is the focal length of the entire zoom lens system at the telephoto end, and fw is the focal length of the entire zoom lens system at the wide angle end.

(31) In the electronic image pickup device described above, the total angle of view at the wide-angle end has a value of 55 degrees or more.
5) The electronic imaging device according to any one of (28).

(32) The wide angle end total angle of view in the electronic image pickup device is 80 degrees or less, as described in (3) above.
The electronic imaging device according to 1).

[0127]

According to the present invention, a reflecting optical element such as a reflecting prism is inserted as much as possible on the object side to bend the optical path (optical axis) of the optical system, especially the zoom lens system, and various conditional expressions are given. Since it is configured to meet, zoom ratio,
While maintaining high optical specification performance such as angle of view, F-number, and small aberration, there is no startup time (lens extension time) to the use state of the camera as seen in the retractable lens barrel.
It is also preferable for waterproof and dustproof, and it is possible to realize a camera having an extremely thin depth direction. In addition, unlike other zoom optical systems such as zoom lenses suitable for retractable lens barrels,
In the future, when the size of the image pickup device is further reduced, it is possible to advantageously further reduce the size and thickness of the camera when the downsized image pickup device is used.

[Brief description of drawings]

FIG. 1 is a sectional view along an optical axis showing an optical configuration according to a first example of a zoom lens used in an electronic image pickup device according to the present invention, showing a state at the time of bending when focusing on an object point at infinity at a wide angle end. ing.

FIG. 2 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens according to Example 1 when focused on an object point at infinity;
Shows the state at the wide-angle end, (b) at the middle, and (c) at the telephoto end.

FIG. 3 is a diagram showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 1 upon focusing on an object point at infinity, showing the state at the wide-angle end.

FIG. 4 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens according to Example 1 upon focusing on an object point at infinity, and shows an intermediate state.

FIG. 5 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification when the zoom lens of Example 1 is focused on an object point at infinity, showing the state at the telephoto end.

FIG. 6 is a diagram showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 1 upon focusing on a short-distance object point, showing the state at the wide-angle end.

FIG. 7 is a diagram showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 1 upon focusing on an object point at a short distance, and shows an intermediate state.

FIG. 8 is a diagram showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 1 upon focusing on a short-distance object point, showing the state at the telephoto end.

FIG. 9 is a cross-sectional view taken along the optical axis showing an optical configuration of a zoom lens according to Example 2 used in the electronic image pickup apparatus according to the present invention, showing a state at the time of bending when focusing on an object point at infinity at the wide-angle end. ing.

FIG. 10 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens according to Example 2 upon focusing on an object point at infinity;
(a) shows the state at the wide-angle end, (b) shows the intermediate state, and (c) shows the state at the telephoto end.

FIG. 11 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 2 upon focusing on an object point at infinity, showing the state at the wide-angle end.

FIG. 12 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification when the zoom lens of Example 2 is focused on an object point at infinity, and shows an intermediate state.

FIG. 13 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 2 upon focusing on an object point at infinity, showing the state at the telephoto end.

FIG. 14 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 2 upon focusing on a short-distance object point, showing the state at the wide-angle end.

FIG. 15 is a diagram showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 2 upon focusing on an object point at a short distance, and shows an intermediate state.

FIG. 16 is a diagram showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 2 upon focusing on a short-distance object point, showing the state at the telephoto end.

FIG. 17 is a cross-sectional view taken along the optical axis showing the optical configuration of a zoom lens according to Example 3 used in the electronic image pickup apparatus according to the present invention, showing a state at the time of bending when focusing on an object point at infinity at the wide angle end. ing.

FIG. 18 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens according to Example 3 upon focusing on an object point at infinity;
(a) shows the state at the wide-angle end, (b) shows the intermediate state, and (c) shows the state at the telephoto end.

FIG. 19 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 3 upon focusing on an object point at infinity, showing the state at the wide-angle end.

FIG. 20 is a diagram showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 3 upon focusing on an object point at infinity, and shows a state in the middle.

FIG. 21 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 3 upon focusing on an object point at infinity, showing the state at the telephoto end.

FIG. 22 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 3 upon focusing on a short-distance object point, showing the state at the wide-angle end.

FIG. 23 is a diagram showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 3 upon focusing on an object point at a short distance, and shows an intermediate state.

FIG. 24 is a diagram showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 3 upon focusing on a short-distance object point, showing the state at the telephoto end.

FIG. 25 is an explanatory diagram showing an example of a pixel array of an electronic image sensor used in each example of the present invention.

FIG. 26 is a graph showing the transmittance characteristics of an example of a near infrared sharp cut coat.

FIG. 27 shows the transmittance characteristics of an example of a color filter provided on the exit surface side of a CCD cover glass CG with a near infrared cut coat or on the exit surface side of another lens with a near infrared cut coat. It is a graph.

FIG. 28 is a diagram showing a color filter arrangement of complementary color mosaic filters.

FIG. 29 is a graph showing an example of wavelength characteristics of a complementary color mosaic filter.

FIG. 30 is an explanatory diagram showing a modification of the diaphragm S used in the electronic image pickup apparatus according to each embodiment of the present invention.

FIG. 31 is an explanatory diagram showing an example of a light amount adjusting means used in the electronic image pickup device according to each embodiment of the present invention.

32 is a perspective view showing a specific example of a state in which the light amount adjusting means shown in FIG. 31 is applied to the present invention.

FIG. 33 is an explanatory diagram showing another example of the light amount adjusting means applicable to the electronic image pickup apparatus according to each embodiment of the present invention.

FIG. 34 is an explanatory diagram showing still another example of the light amount adjusting means applicable to the electronic image pickup device according to each embodiment of the present invention.

FIG. 35 is a schematic configuration diagram showing an example of a rotary focal plane shutter that is one of the focal plane shutters for adjusting the light receiving time applicable to the electronic imaging device according to each embodiment of the present invention, and FIG. Back view, (b)
Is a front view.

36 (a) to 36 (d) are views showing how the rotary shutter curtain B shown in FIG. 35 rotates, as viewed from the image plane side.

FIG. 37 is a conceptual diagram of a configuration in which the folding zoom lens according to the present invention is incorporated in a photographing optical system 41 of a digital camera, and is a front perspective view showing an appearance of the digital camera 40.

38 is a rear perspective view of the digital camera 40 shown in FIG.

39 is a cross-sectional view showing the configuration of the digital camera 40 shown in FIG.

FIG. 40 is a personal computer 3 which is an example of an information processing apparatus in which the folding zoom lens of the present invention is incorporated as an objective optical system.
It is a front perspective view which opened the cover of 00.

41 is a sectional view of the taking optical system 303 of the personal computer 300 shown in FIG.

42 is a side view of FIG. 40. FIG.

43A and 43B are diagrams showing a mobile phone as an example of an information processing apparatus in which the folding zoom lens of the present invention is incorporated as a photographing optical system, where FIG. 43A is a front view of the mobile phone 400 and FIG.
(a) is a side view and (c) is a cross-sectional view of the photographing optical system 405.

[Explanation of symbols]

A shutter substrate A1 substrate opening B rotary shutter curtain C rotary shutter curtain rotation axes D1, D2 gears CG CCD cover glass E observer eye G1 first lens group G2 second lens group (first moving lens group) G3 3 lens groups (second moving lens group) G4 4th lens group G5 5th lens group I Imaging surface L1 ₁ Negative meniscus lens L1 _{2 with} convex surface facing the object side Biconvex positive lens L1 ₂ 'Concave surface facing the object side Positive meniscus lens L1 ₃ Biconcave negative lens L1 ₄ Positive meniscus lens L2 ₁ with convex surface facing the object side Positive meniscus lens L2 ₂ Negative meniscus lens L2 ₃ with convex surface facing the object side concave on the positive lens L3 ₁ positive meniscus lens convex toward the object side L3 ₁ 'biconvex positive lens L4 ₁ biconvex positive lens L4 _1' biconcave negative lens L4 ₁ "object side The negative lens L4 ₂ biconcave negative lens L4 ₂ 'biconvex positive lens L4 ₂ "positive lenses R1 reflective optical element S aperture stop 1A having a convex surface on the image side has a planar object side having a flat surface to have the image side, 1B, 1C, 1D Aperture 10 Turret 11 Rotational axis 40 Digital camera 41 Imaging optical system 42 Photographing optical path 43 Viewfinder optical system 44 Viewfinder optical path 45 Shutter 46 Flash 47 Liquid crystal display monitor 49 CCD 50 Cover member 51 Processing means 52 Recording means 53 Objective optical system for viewfinder 55 Porro prism 57 Field frame 59 Eyepiece optical system 103 Control system 104 Imaging unit 112 Objective lens 113 Mirror frame 114 Cover glass 160 Imaging unit 162 Imaging element chip 166 Terminal 300 Personal computer 301 Keyboard 302 Monitor 303 Imaging optical system 304 Shooting light Path 305 image 400 mobile phone 401 microphone section 402 speaker section 403 input dial 404 monitor 405 shooting optical system 406 antenna 407 shooting optical path

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 5/335 H04N 5/335 V // G03B 11/00 G03B 11/00 F term (reference) 2H048 GA07 GA09 GA14 GA33 GA36 GA43 GA46 GA61 2H083 AA05 AA26 AA33 AA53 2H087 KA03 MA14 PA07 PA08 PA20 PB10 PB11 QA02 QA06 QA07 QA17 QA21 QA26 QA33 QA34 QA39 QA41 QA42 QA45 RA05 RA12 RA13 RA32 RA42 RA43 SA24 SA26 SA29 SA31 SA63 SA64 SA72 SA75 SB05 SB06 SB14 SB22 SB33 TA01 TA03 5C022 AA13 AB23 AB66 AC42 AC54 AC65 AC66 5C024 BX01 DX01 DX04 EX42 EX48 GX02

Claims (6)

[Claims] 1. A first lens unit having a negative refracting power in order from the object side and including a reflective optical element for bending an optical path, which is fixed during zooming, has a positive refracting power, and from the wide-angle end. A second lens group that moves only to the object side when zooming to the telephoto end, a third lens group that moves differently from the second lens group when zooming, and a fourth lens having an aspheric surface A total of three lens groups each including two or more cemented lens components, the two lens groups including the second lens group and the third lens group.
A zoom lens characterized by comprising three or less lens components and satisfying the following conditional expression (1). 1.0 <−β _Rt <2.6 (1) where β _Rt is a composite magnification at the telephoto end when focusing on an object point at infinity after the second lens unit. 2. A first lens unit, which has a negative refracting power in order from the object side and includes a reflective optical element for bending an optical path and is fixed during zooming, has a positive refracting power, and from the wide-angle end. A second lens group that moves only to the object side when zooming to the telephoto end, a third lens group that moves differently from the second lens group when zooming, and a fourth lens having an aspheric surface A first sub-lens group, in which the first lens group has, in order from the object side, a front sub-group having a negative lens having a convex surface facing the object side, a reflective optical element for bending the optical path, and a negative refracting power. A zoom lens characterized in that the zoom lens is composed of a rear subgroup having and satisfies the following conditional expressions (7) and (8). 0.5 <(R _11F + R _11R ) / (R _11F −R _11R ) <5.0 (7) 0 <f ₁₁ / f ₁₂ <1.2 (8) where R _11F is the first lens group. R _11R is the radius of curvature on the optical axis of the object side surface of the negative lens of the front side subgroup of, and R _11R is the radius of curvature of the image side surface of the negative lens of the front side subgroup of the first lens group,
f ₁₁ is the focal length of the front sub-group of the first lens group, and f ₁₂ is the focal length of the rear sub-group of the first lens group. 3. An electronic image pickup apparatus comprising the zoom lens according to claim 2 and an electronic image pickup element arranged on the image side thereof. 4. The first lens group, in order from the object side,
A front subgroup having a negative lens with a convex surface facing the object side, a reflective optical element for bending the optical path, and a rear subgroup having negative refractive power, the following conditional expression (7), An electronic image pickup apparatus comprising: the zoom lens according to claim 1 that satisfies the item (8); and an electronic image pickup element disposed on the image side thereof. 0.5 <(R _11F + R _11R ) / (R _11F −R _11R ) <5.0 (7) 0 <f ₁₁ / f ₁₂ <1.2 (8) where R _11F is the first lens group. R _11R is the radius of curvature on the optical axis of the object side surface of the negative lens of the front side subgroup of, and R _11R is the radius of curvature of the image side surface of the negative lens of the front side subgroup of the first lens group,
f ₁₁ is the focal length of the front sub-group of the first lens group, and f ₁₂ is the focal length of the rear sub-group of the first lens group. 5. The front side sub group is composed of one negative lens having an aspherical surface, and the rear side sub group is composed of two lens components having different signs of refracting power, and the following conditional expression (9) is satisfied. An electronic image pickup apparatus comprising: the zoom lens according to claim 2 or 4, and an electronic image pickup element arranged on an image side thereof. 0.4 <(R _12R / R _13F ) ^P <1.6 (9) where R _12R is the object side surface of the air lens formed between the two lens components of the rear subgroup of the first lens group. The radius of curvature on the optical axis, R _13F is the radius of curvature on the optical axis of the image side surface of the air lens formed between the two lens components of the rear sub-group of the first lens group, and P is 2 The order of the lens components from the object side is P = 1 when the negative lens component and the positive lens component are arranged in this order, and P = −1 when the positive lens component and the negative lens component are arranged in this order. To do. 6. The second lens group has a cemented lens component, and any cemented surface included in the cemented lens component and the medium of the lens on both sides thereof satisfy the following conditional expressions (3) and (4). An electronic image pickup apparatus comprising: the zoom lens according to any one of Claims 1, 2, 4, and 5 which is satisfied; and an electronic image pickup element arranged on an image side thereof. 0 <L / R _21C <1.4 (3) 15 <ν _21F −ν _21R (4) where L is the diagonal length of the effective image pickup area of the electronic image pickup device, R
_21C is the radius of curvature of the cemented surface in the second lens group on the optical axis, ν _21F is the Abbe number of the medium of the lens on the object side of the cemented surface in the second lens group on the d-line basis, and ν _21R is the second It is the Abbe number on the d-line basis of the medium of the lens on the image side of the cemented surface in the lens group.