JP2003329930A - Zoom lens and electronic image pickup device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a zoom lens eliminating the need of start-up time to a using condition as seen in a collapsible mount type lens barrel, desirable in terms of water- proof and dust-proof effects, easily taking constitution to bend the optical path of an optical system by a catoptric element in order to make a camera extremely thin in the depth direction, having high optical specifications concerning zoom ratio, the angle of view, and F-value, and being little in aberration, and further capable of shortening the length obtained after bonding the optical path, and to provide an electronic image pickup device having the zoom lens. <P>SOLUTION: The zoom lens is provided with a lens group G1 nearest to an object side, which is fixed on an optical axis at the time of varying power and at the time of focusing operation, a lens group G5 nearest to an image side, which is fixed on the optical axis at least at the time of focusing operation, and lens group G2 to G4 positioned between the lens groups G1 and G5 and moving on the optical axis at the time of varying power. The lens group G5 is constituted of a negative lens component L1<SB>1</SB>, the catoptric element R1 having a reflection surface for bending the optical path, and a positive lens component L1<SB>2</SB>in order from the object side, and is provided with at least one aspherical surface. <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. It is another object of the present invention to provide a zoom lens that can be shortened not only in the depth direction but also after the optical path is bent, and an electronic image pickup apparatus including the zoom lens.

[0006]

In order to achieve the above object, the zoom lens according to the first aspect of the present invention is located at the most object side, and is the most object that is fixed on the optical axis both during zooming and during focusing operation. A side lens group, located closest to the image side, located at least between the most image side lens group that is fixed on the optical axis during focusing operation, the most object side lens group, and the most image side lens group;
At least a moving lens group that moves on the optical axis during zooming, the most object side lens group, in order from the object side, a negative lens component, a reflective optical element having a reflective surface for bending the optical path, And a positive lens component, and the lens group closest to the image side has at least one aspherical surface.

The zoom lens according to the second aspect of the present invention has, in order from the object side, a reflective optical element having a reflecting surface for bending the optical path, and serves as a first object-side lens group that is fixed during zooming. A second lens group, which has a negative refracting power and which moves on the optical axis during zooming.
It has a lens group, a third lens group having a positive refractive power and moving on the optical axis at the time of zooming, and a most image side lens group arranged on the most image side. However, it is characterized in that the second lens group reciprocates along a convex locus toward the image side when zooming from the wide-angle end to the telephoto end when focusing on an object point at infinity.

The zoom lens according to the third aspect of the present invention is characterized in that, in the second aspect of the present invention, the second lens group is extended toward the object side when focusing on a short-distance object point.

The zoom lens according to the fourth aspect of the present invention is the zoom lens according to the second aspect of the present invention, which is provided between the third lens group and the most image-side lens group when performing a focusing operation on an object point at a short distance. It is characterized in that a lens group that moves on the axis is arranged.

The zoom lens according to the fifth invention is the zoom lens according to any one of the second to fourth inventions.
The lens group is composed of a cemented lens component in which a positive lens and a negative lens are cemented, and two lens components of a single lens,
When zooming from the wide-angle end to the telephoto end, it moves only to the object side.

An electronic image pickup apparatus according to the sixth aspect of the present invention includes the zoom lens according to any one of the first to fifth aspects of the present invention.
And an electronic image pickup device arranged on the image side.

[0012]

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. The basic configuration of the zoom lens system according to the present invention includes a lens group that moves during zooming, and does not require a start-up time (lens protrusion time) to use the camera as seen in a collapsible lens barrel and is waterproof. As it is advantageous in dust protection,
The lens group that is closest to the object side of the lens system (hereinafter referred to as the first lens group) is fixed during zooming and focusing, and in order to make the depth direction of the camera extremely thin, the most object side of the lens system A reflective optical element for bending the optical path is provided in the first lens group on the side.

However, if a reflective optical element for bending the optical path is provided in the first lens group, the entrance pupil inevitably becomes deeper, and the diameter and size of each optical element constituting the first lens group is originally large. However, it becomes bloated further, and eventually the optical path bending cannot be physically established.
Therefore, the first lens group comprises a negative lens having a convex surface directed toward the object side, a reflective optical element for bending the optical path, and a positive lens in order from the object side to make the entrance pupil shallow.

On the other hand, the negative lens and the positive lens of the first lens group are arranged apart from each other while having a certain level of strong power in order to secure a space for bending the optical path. Will be done. Therefore, the off-axis aberrations such as coma, astigmatism, and distortion are inevitably aggravated, but this can be corrected by introducing an aspherical surface into the most image-side lens group (final lens group).

Further, the correction amount of off-axis aberration by the aspherical surface of the final lens group is considerably large, and when rear focus is performed using this, the off-axis aberration changes remarkably. Therefore, it is better to make the final lens group immobile at the time of focusing, and move another lens group for focusing.

To physically establish the above-mentioned bending,
It is preferable to satisfy the following conditional expressions (1) and (2), and also conditional expressions (3) and (4). 1.0 <−f11 / √ (fw · fT) <2.5 (1) 1.4 <f12 / √ (fw · fT) <3.2 (2) 0.7 <d / L <2 .0 (3) 1.55 <npri (4) where f11 is the focal length of the negative lens component in the most object side lens group, and f12 is the most object side lens group,
The focal length of the positive lens component, fw is the focal length of the entire system at the wide-angle end of the zoom lens, fT is the focal length of the entire system at the telephoto end of the zoom lens, and d is the image-side apex of the negative lens component in the most object-side lens unit. To the apex of the object side surface of the positive lens component measured along the optical axis, L is the diagonal length of the effective image pickup area (substantially rectangular) of the electronic image pickup device, npri
Is the refractive index of the medium at the d-line when the reflective optical element that is the optical path bending element of the first lens group is a prism (the lens component in the present application is the lens surface closest to the object side and the lens surface closest to the image side). (A single lens or a cemented lens is one unit, which is a lens in which only the lens surface is in contact with an air gap and does not include an air gap between them.).

In order to make the entrance pupil shallow and to physically bend the optical path, the power of the lens elements at both ends of the first lens group is made strong as in the conditional expressions (1) and (2). Is good. If both upper limits of conditional expressions (1) and (2) are exceeded, the entrance pupil remains deep, and when trying to secure a certain angle of view, the diameter and size of each optical element forming the first lens group becomes It becomes bloated, and it becomes difficult to physically establish the optical path bending. On the other hand, when the value goes below the lower limit of conditional expressions (1) and (2), on the contrary, the diameter of the positive lens in the first lens group increases, and it is difficult to correct off-axis aberrations such as coma, astigmatism, and distortion. become.

Conditional expression (3) is a conditional expression that regulates the length measured along the optical axis necessary for providing the reflective optical element for bending the optical path. The value of conditional expression (3) should be as small as possible, but if the value is below the lower limit, optical path bending is not established, or the light flux that contributes to image formation at the peripheral portion of the screen does not reach the image plane satisfactorily. Ghosts are likely to occur. On the other hand, if the upper limit of conditional expression (3) is exceeded, the conditional expression
As in the cases of (1) and (2), it becomes difficult to correct each off-axis aberration.

From the above point of view, in order to shorten the air-equivalent length d of the conditional expression (3), the optical path bending element of the first lens group has a plane of incidence and a plane of exit, or both sides thereof. It is preferable to use a prism having a surface different from the curvature of the lens surface of the lens to be used so that the medium refractive index thereof satisfies the conditional expression (4). When the value goes below the lower limit of the conditional expression (4), it becomes difficult to physically bend the optical path or it becomes difficult to correct each off-axis aberration. However, conditional expression (4) has an upper limit of 1.
It is recommended that the number 9 is not exceeded. When the upper limit value of 1.9 is exceeded, the material of the prism becomes high.

The following conditional expressions (1 '), (2'), (3 '),
It is even better to satisfy at least one of (4 ')'. 1.2 <-f11 / √ (fw · fT) <2.2 ... (1 ′) 1.5 <f12 / √ (fw · fT) <3.0… (2 ′) 0.8 <d / L <1.8 ... (3 ') 1.65 <npri ... (4') Furthermore, at least one of the following conditional expressions (1 "), (2"), (3 "), (4") Best to meet one. 1.4 <-f11 / √ (fw · fT) <1.9 (1 ″) 1.6 <f12 / √ (fw · fT) <2.8… (2 ″) 0.9 <d / L <1.6… (3 ") 1.75 <npri… (4")

Further, as described above, when the negative lens and the positive lens of the first lens group are arranged at a distance from each other while having strong powers above a certain level, the variation amount of the chromatic aberration of magnification due to the magnification change is also increased. Tends to grow. Therefore, the following conditional expressions (5) and (6) should also be satisfied. 26 <ν1n (5) −0.15 <√ (fw · fT) / f1 <0.5 (6) However, ν1N is based on the d-line of the medium of the negative single lens of the lens group closest to the object. The Abbe number, f1 is the focal length of the lens group closest to the object.

When the value goes below the lower limit of the conditional expression (5), the variation in lateral chromatic aberration during zooming becomes large, which is not preferable. There is no limitation on the upper limit of conditional expression (5). Conditional expression
When the value exceeds the upper limit of (6), it becomes difficult to correct off-axis aberrations and chromatic aberrations. In particular, chromatic aberration of magnification may be difficult to correct even if conditional expression (5) is satisfied. On the other hand, conditional expression (6)
When the value goes below the lower limit of, the aberration variation due to the movement of the lens group that moves for zooming may increase. It is more preferable to satisfy either of the following conditional expressions (5 ') and (6'). 30 <ν1n (5 ')-0.1 <√ (fw · fT) / f1 <0.4 (6') Furthermore, either of the following conditional expressions (5 ") and (6") is satisfied. And the best. 33 <ν1n ... (5 ") -0.05 <√ (fw · fT) / f1 <0.3 ... (6")

From the above, in the zoom lens according to the present invention, the lens unit closest to the object is stationary during zooming and focusing, and the negative lens and the reflective optical element for bending the optical path are arranged in order from the object side. And a positive lens, an aspherical surface is introduced into the lens group closest to the image side, it is immovable during focusing, and a lens group that is movable for zooming is provided between the two groups. Good to do.

Next, a method of zooming and focusing a zoom lens having a reflective optical element for bending the optical path will be described. The following three methods are conceivable as the scaling method. From the object side, in order from the object side, a first lens group having a negative refracting power and including a reflecting optical element and immovable, and a second lens group having a positive refracting power and moving only to the object side during zooming from the wide-angle end to the telephoto end. A zoom method that includes a lens unit, a third lens unit that can move during zooming and focusing, and a final lens unit that has an aspheric surface and is immovable. From the object side, in order from the object side, a first lens group having a positive refracting power and including a reflection optical element and not moving, and a second lens group having a negative refracting power and moving only to the image side at the time of zooming from the wide-angle end to the telephoto end. A zoom method that includes a lens unit, a third lens unit that moves only in the opposite direction to the second lens unit when zooming, and a final lens unit that can move when focusing. In order from the object side, the first lens group that has a positive refractive power and includes a reflective optical element and is immovable, and the negative lens having a negative refractive power and a reciprocating movement that is convex toward the image side during zooming from the wide-angle end to the telephoto end. A zoom consisting of a second lens group which has a positive refractive power, a third lens group which has a positive refractive power and moves only to the object side at the time of zooming from the wide-angle end to the telephoto end, and a final lens group which has an aspheric surface and is immovable. method.

First, the above-mentioned method has a drawback that it is difficult to apply power to the third lens group and the amount of movement becomes too large in order to secure a zoom ratio. When the amount of movement increases, the focus becomes slower and the power consumption increases. Next, in the above method, the power of the negative lens on the object side of the first lens group is weak, or the power of the positive lens on the image side of the first lens group is too strong, so make the entrance pupil shallow. Also, there are difficulties in correction of various off-axis aberrations, correction of lateral chromatic aberration, and the like. Therefore, the above method is adopted in the present invention. Specifically, in order from the object side, a first lens group having a reflective optical element for bending an optical path and fixed during zooming, and a second lens group having negative refractive power and movable during zooming, It has a third lens group having a positive refracting power and movable during zooming, and a final lens group, and when zooming from the wide-angle end to the telephoto end when focusing on an object point at infinity, the second lens group is a It is a zoom lens that moves (reciprocates) along a convex locus on the axis toward the image side. If you do this The drawbacks of the above-mentioned method can be solved.

Further, it is preferable that the following conditional expressions (7) and (8) are satisfied. 0.3 <-βRw <0.8 (7) 0.8 <fRw / √ (fw · fT) <1.8 (8) where βRw is at the wide-angle end when focusing on an object point at infinity. Composite magnification after the third lens group, fRw is a composite focal length after the third lens group at the wide-angle end when focusing on an object point at infinity, fw is a focal length of the entire system at the wide-angle end of the zoom lens, and fT is a zoom It is the focal length of the entire system at the telephoto end of the lens.

When the value goes below the lower limit of conditional expression (7), a sufficiently high zoom ratio cannot be obtained in the entire zoom lens system, or the moving space becomes too large and the size becomes large. on the other hand,
Exceeding the upper limit of conditional expression (7) is rare in theory, but it still requires a lot of moving space. Conditional expression (8)
Below the lower limit of, the zooming efficiency deteriorates due to the reduction of the composite system magnification after the third lens group. On the other hand, the conditional expression
When the value exceeds the upper limit of (7), the focal length of the compound system after the third lens group becomes long and the zooming efficiency deteriorates.

It is even better if either of the following conditional expressions (7 ') and (8') is satisfied. 0.35 <−βRw <0.75 (7 ′) 0.9 <fRw / √ (fw · fT) <1.6 (8 ′) Further, the following conditional expressions (7 ″) and (8 ″) ) It is the best to meet either. 0.4 <-βRw <0.7 (7 ") 1.0 <fRw / √ (fw · fT) <1.5 (8")

As for a method of focusing on an object point at a closer distance, the second lens group is extended to the object side, or
It is preferable that another lens group that is movable for focusing be provided between the third lens group and the most image-side lens group to move it on the optical axis. When the second lens group is extended to the object side as a method of focusing on an object point at a short distance, the following conditional expression (9) should be satisfied. 0.16 <D12min / √ (fw · fT) <0.26 (9) However, D12min is a range that can be taken between the first lens group and the second lens group when focusing on an object point at infinity. Minimum value, f
w is the focal length of the entire system at the wide-angle end of the zoom lens, f
T is the focal length of the entire system at the telephoto end of the zoom lens.

The second lens group is capable of focusing to a considerably close object point with a slight amount of movement.
When the value goes below the lower limit of (9), there is insufficient space to move the second lens group for focusing, and it interferes with the first lens group, or it is impossible to focus on a closer object point. become.
On the other hand, if the upper limit of conditional expression (9) is exceeded, the entrance pupil tends to become deep, and trying to make it shallow tends to interfere with aberration correction and magnification assurance. It is even better if the following conditional expression (9 ′) is satisfied. 0.17 <D12min / √ (fw · fT) <0.24 (9 ′) Further, it is best to satisfy the following conditional expression (9 ′). 0.18 <D12min / √ (fw · fT) <0.22 (9 ”)

On the other hand, the third method for focusing on a short-distance object point is
When another lens group that is movable for focusing is provided between the lens group and the lens group closest to the image side and is moved on the optical axis, the following conditional expression (10) should be satisfied. . 1.0 <| fF | / √ (fw · fT) <6.0 (10) where fF is the distance to the short-distance object point arranged between the third lens group and the image-side lens group. The focal length of the lens group that moves on the optical axis during the focusing operation, fw is the focal length of the entire system at the wide-angle end of the zoom lens, and fT is the focal length of the entire system at the telephoto end of the zoom lens.

If the upper limit of conditional expression (10) is exceeded, the amount of movement of the lens group that moves during focusing becomes large, which is not preferable. On the other hand, when the value goes below the lower limit of the conditional expression (10), it becomes difficult to correct various off-axis aberrations, or the variation amount of the exit pupil position at the time of zooming becomes too large, which easily causes shading. It is even better to satisfy the following conditional expression (10 ′). 1.5 <| fF | / √ (fw · fT) <5.0 (10 ′) Furthermore, it is better if the following conditional expression (10 ″) is satisfied: 2.0 <| fF | / √ (fw・ FT) <4.0 (10 ")

Next, a method for satisfactorily ensuring the variable magnification and correcting the aberration will be described. It is the configuration of the third lens group that is deeply involved in both of these. The larger the number of components, the more advantageous it is, but this hinders the achievement of the maximum goal of miniaturization.
For this reason, it is important to make the number of sheets as small as possible. Since the third lens group has a variable power function, it moves only to the object side when zooming from the wide-angle end to the telephoto end, but it is necessary to configure the third lens group for aberration correction. A total of three lenses including one positive lens and one negative lens are enough. However, the decentering sensitivity of the negative lens (the amount of increase in aberration with respect to the unit decentering amount) is large. Therefore, it is preferable to cement the negative lens to any positive lens in the third lens group. Therefore, the configuration in the third lens group is as follows. In order from the object side, a positive single lens and a cemented lens component of a positive lens and a negative lens B.I. In order from the object side, there are two types, a cemented lens component of a positive lens and a negative lens, and a single lens.

Further, in order to keep the moving space of the second lens group and the third lens group moving during zooming small, the third lens group is used.
The magnification of the lens group is preferably set to -1 at the intermediate focal length. However, if the first lens group of the present invention is configured as described above, the image point of the system before the third lens group, that is, the object point for the third lens group is inevitably farther to the object side than usual, so that Since the magnification of the lens group is close to zero, a lot of moving space is required.

However, when the third lens group is constructed as described above in A, there is an advantage that the disadvantage can be eliminated because the front principal point of the third lens group is located closer to the object side. Similarly, since the rear principal point is also located closer to the object side, no wasted space can be formed after the third lens group. Therefore,
This is effective in shortening the length after the bent portion of the optical path. On the other hand, when the third lens group is configured as in the above A, the exit pupil position tends to be close, and the amount of change in the F value due to zooming is large, making it more susceptible to diffraction at the telephoto end. There is a drawback that. Therefore, when the third lens group is configured as described above in A, it is suitable to use a slightly larger image pickup device in addition to easy miniaturization.

On the other hand, in the case where the third lens group is constructed as described above in B, on the contrary, the length becomes longer than in the case where it is constructed as in A above, but at the exit pupil position and F at the time of zooming. Since it is advantageous in terms of value change, a smaller image sensor is suitable.

When the third lens group is constructed as in the above A, the following conditional expression (11A) is satisfied, and when the third lens group is constructed as in the above B, the following conditional expression is satisfied. It is better to satisfy (11B). 0.4 < _RC3 / _RC1 <0.85 (11A) 0.8 < _RC3 / _RC1 <1.3 (11B) where _RC3 is the most image of the cemented lens component in the third lens group. The radius of curvature of the side surface of the cemented lens component on the optical axis, R _C1, is the radius of curvature of the surface of the cemented lens component closest to the object side on the optical axis.

When the upper limits of conditional expressions (11A) and (11B) are exceeded,
Although it is advantageous for correcting spherical aberration, coma aberration, and astigmatism of all system aberrations, the effect of mitigating decentration sensitivity due to cementing is small. On the other hand, if the lower limit values of the conditional expressions (11A) and (11B) are exceeded, it becomes difficult to correct spherical aberration, coma aberration, and astigmatism of all system aberrations. When the third lens group is configured as in the above A, the following conditional expression (11′A) is satisfied, and when the third lens group is configured as in the above B, the following conditional expression (11 11'B) is even better. _{0.5 <R C3 / R C1 <} 0.8 ... (11'A) 0.85 <R C3 / R C1 <1.2 ... (11'B) In addition, the third lens group as described above A In the case of constructing, the following conditional expression (11 "A) is satisfied, and the third lens group is set to the above B.
In the case of such a constitution, it is best to satisfy the following conditional expression (11 "B): 0.6 < _RC3 / _RC1 <0.7 (11" A) 0.9 < _RC3 / R _C1 <1.1 ... (11 "B)

Further, regarding the chromatic aberration correction, the following conditional expression
(12A), (13A) (The above is the third lens group as described above in A.
Condition) or conditional expressions (12B), (13B) (above, the first
When the three lens groups are configured as in B) above,
good.       -0.3 <L / R_C2  <1.0 ... (12A)       15 <ν_CP  −ν_CN                              … (13A)       -0.1 <L / R_C2  <0.8 ... (12B)       15 <ν_CP  −ν_CN                              … (13B) However, L is the diagonal length (mm) of the image sensor used.
It The image sensor has a wide-angle end angle of view of 55 degrees.
It is premised that it is used to include the above. R _C2Is the
On the optical axis of the cemented surface of the cemented lens component in the three lens groups
Radius of curvature of, ν_CPIs the cemented lens component in the third lens group.
Abbe number of the positive lens medium, ν_CNOf the third lens group
Abbe number of the negative lens medium in the cemented lens component
It

If the lower limits of conditional expressions (12A) and (12B) are exceeded,
Although it is advantageous for correction of axial chromatic aberration and lateral chromatic aberration, chromatic aberration of spherical aberration is likely to occur. In particular, even if spherical aberration at the reference wavelength can be corrected well, short-wave spherical aberration is overcorrected. This is not preferable because it causes color bleeding. On the other hand, if the upper limits of (9A) and (9B) are exceeded, axial chromatic aberration and lateral chromatic aberration will be undercorrected and short-wave spherical aberration will be undercorrected. If the lower limits of conditional expressions (10A) and (10B) are exceeded, axial chromatic aberration is likely to be undercorrected. On the other hand, there is no natural combination of media that exceeds the upper limits of conditional expressions (10A) and (10B).

When the third lens group is constructed as in the above A, at least one of the following conditional expressions (12'A) and (13'A) is satisfied, or the third lens group is The above
When constructing like B, the following conditional expressions (12'B), (13'B)
It is even better to satisfy at least one of the above. -0.1 <L / R _C2 <0.8 (12'A) 20 <ν _CP −ν _CN (13'A) 0 <L / R _C2 <0.6 (12'B) 20 < ν _CP −ν _CN … (13'B)

Further, when the third lens group is constructed as in the above A, at least one of the following conditional expressions (12 "A) and (13" A) is satisfied, or the third lens group is Is configured as in B above, the following conditional expressions (12 "B), (13"
It is best to satisfy at least one of B). 0.1 <L / R _C2 <0.6 (12 "A) 25 <ν _CP -ν _CN (13" A) 0.15 <L / R _C2 <0.4 ... (12 "B) 25 <Ν _CP −ν _CN … (13 "B)

Further, the above conditional expressions (13A), (13'A), (13 "
For A), (13B), (13'B), and (13 "B), ν _{VCP −} ν _VCN
May not exceed 90. There is no combination of media that exceeds the upper limit of 90 in nature. Furthermore, it is desirable that ν _VCP −ν _VCN does not exceed 60. If the upper limit of 60 is exceeded, the material used becomes expensive.

Further, in the zoom lens according to the present invention, it is preferable to introduce an aspherical surface into the object-side negative lens in the first lens group. Furthermore, the image side positive lens in the first lens group,
It is preferable to satisfy the following conditional expression (14). _{-2.0 <(R 1PF + R 1PR} ) / (R 1PF -R 1PR) <1.0 ... (14) However, R _1PF is on the optical axis of the object side surface of the positive lens component of the most object side lens unit The radius of curvature, R _1PR, is the radius of curvature on the optical axis of the image side surface of the positive lens component of the lens unit closest to the object.

If the upper limit of conditional expression (14) is exceeded, high-order lateral chromatic aberration is likely to occur. On the other hand, when the value goes below the lower limit of conditional expression (14), the entrance pupil tends to be deep. The following conditional expression
It is even better to satisfy (14 '). _{-1.7 <(R 1PF + R 1PR} ) / (R 1PF -R 1PR) <0.5 ... (14 ') In addition, the following conditional expression (14') meets the best of. -1.4 <( _{R 1PF + R 1PR) / (} R 1PF -R 1PR) <0.1 ... (14 ")

Further, since the focal length of the second lens group is long, it is sufficient to have two lenses in order from the object side, a negative lens and a positive lens. Furthermore, joining is preferable because the sensitivity to eccentricity can be reduced. Then, the cemented lens component may satisfy the following conditional expression (15). −1.5 <(R _2F + R _2R ) / (R _2F −R _2R ) <0.8 (15) where R _2F is the optical axis of the most object side surface of the second lens group (the cemented lens component). The radius of curvature above, R _2R, is the radius of curvature on the optical axis of the surface of the second lens group (the cemented lens component) that is closest to the image side.

If the upper limit of conditional expression (15) is exceeded, the entrance pupil tends to become deep. On the other hand, when the value goes below the lower limit of conditional expression (15), various off-axis aberrations are likely to occur. The following conditional expression
It is even better to satisfy (15 '). −1.2 <(R _2F + R _2R ) / (R _2F −R _2R ) <0.5 (15 ′) Further, it is best if the following conditional expression (15 ″) is satisfied: −0.9 <( R _2F + R _2R ) / (R _2F -R _2R ) <0.2… (15 ")

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 retractable 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 (16) F ≧ a (16) 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 proportionally smaller, and the deterioration of image quality 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 (16), 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 (16) (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 (17). 1.8 <fT / fw (17) 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 conditional expression (17), 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 (18) and (19). τ600 / τ550 ≧ 0.8 (18) τ700 / τ550 ≦ 0.08 (19) 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 (18 ') and (19')
It is even better to meet. τ600 / τ550 ≧ 0.85 (18 ′) τ700 / τ550 ≦ 0.05 (19 ′) Further, it is best to satisfy the following conditional expressions (18 ″) and (19 ″). τ600 / τ550 ≧ 0.9… (18 ") τ700 / τ550 ≦ 0.03… (19")

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 to satisfy the following conditional expressions (20) and (21). τ400 / τ550 ≦ 0.08 (20) τ440 / τ550 ≧ 0.4 (21) It is more preferable to satisfy the following conditional expressions (20 ′) and (21 ′). τ400 / τ550 ≤ 0.06 (20 ') τ440 / τ550 ≥ 0.5 (21') Further, it is best to satisfy the following conditional expressions (21 ") and (22"). .tau.400 / .tau.550.ltoreq.0.04 (21 ") .tau.440 / .tau.550 .gtoreq.0.6 (22") It is to be noted that these filters should be installed between the imaging optical system and the image pickup device.

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, so that 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.

[0060]

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, in order from the object side, a zoom lens and a CCD which is an electronic image pickup element. 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
It has a second lens group G2 which is a first moving lens group, an aperture stop S, a third lens group G3 which is a second moving lens group, a fourth lens group G4 and a fifth lens group G5. . The first lens group G1 is composed of, in order from the object side, a convex surface and a negative meniscus lens L1 ₁ with its object side, a reflecting optical element R1 having a reflecting surface for bending the optical path, a biconvex positive lens L
1 and ₂ and have a positive 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 is composed of, in order from the object side, a cemented lens of a biconcave negative lens L2 ₁ and a positive meniscus lens L2 ₂ having a convex surface facing the object side, and has a negative refracting power as a whole. ing. Third lens group G
3 is composed of, in order from the object side, a cemented lens of a positive meniscus lens L3 ₁ having a convex surface facing the object side and a negative meniscus lens L3 ₂ having a convex surface facing the object side, and a biconvex positive lens L3 _3. And has a positive refracting power as a whole. Fourth
The lens group G4 is composed of a negative meniscus lens L4 ₁ having a convex surface directed toward the object side. The fifth lens group G5 includes, in order from the object side, a biconvex positive lens L5 ₁ and a biconcave negative lens L5 _2.
It is composed of a cemented lens with.

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 fifth lens group G5 are fixed, and the second lens group G2 is at the image side. And reciprocate along a convex locus (that is, move to the image side to temporarily widen the distance to the first lens group G1 and then move to the object side to reduce the distance to the first lens group G1), The third lens group G3 moves together with the aperture stop S only toward the object side. When focusing on a short-distance object point, the second lens group G2 is extended to the object side, and the fourth lens group G4 moves on the optical axis. The positions of the first lens group G1 and the fifth lens group G5 are 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 L3 ₁ whose convex surface faces the object side in the third lens group G3. _On the object side of the biconvex positive lens L5 ₁ in the fifth lens group G5.

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 = 27.7123 d ₁ = 0.7000 n _d1 = 1.80610 ν _d1 ＝ 40.92 r ₂ ＝ 5.9116 (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 = 11.2199 d ₅ = 1.3000 n _d5 = 1.72916 ν _d5 ＝ 54.68 r ₆ ＝ -569.8906 d ₆ ＝ D6 r ₇ ＝ -8.0963 d ₇ ＝ 0.7000 n _d7 ＝ 1.72916 ν _d7 ＝ 54.68 r ₈ = 6.5000 d ₈ = 1.3000 n _d8 = 1.84666 ν _d8 = 23.78 r ₉ = 24.9922 d ₉ = D 9 r ₁₀ = ∞ (aperture) d ₁₀ = 0 r ₁₁ = 4.5958 (aspherical surface) d ₁₁ = 1.8000 n _{d 11} = 1.74320 v _d11 = 49.34 r ₁₂ = 20.0000 d ₁₂ = 0.7000 n _d12 = 1.84666 v _d12 = 23.78 r ₁₃ = 4.4049 d ₁₃ = 0.3000 r ₁₄ = 7.9947 d ₁₄ = 1.6000 n _d14 = 1.72916 v _d14 = 54.68 877 r _{15 d 15 = D15 r 16 = 19.9833} d 16 = 0.7000 n d16 = 1.48749 ν d16 = 70.23 r 17 = 6.0725 d 17 = D17 r 18 = 7.4083 ( aspherical) d ₁₈ = 1.6000 n _{d18 = 1.74320 ν d18 = 49.34 r} 19 = -12.0000 d 19 = 0.7000 n d19 = 1.84666 ν d19 = 23.78 r 20 = 40.3531 d 20 = 0.7000 r 21 = ∞ d 21 = 0.6000 n d21 = 1.51633 ν d21 = 64.14 r 22 = ∞ d ₂₂ = D 22 r ₂₃ = ∞ (imaging plane) d ₂₃ = 0

Aspheric coefficient 2nd surface K = 0 A ₂ = 0 A ₄ = -6.4155 × 10 ^-4 A ₆ = 2.5228 × 10 ^-6 A ₈ = -8.769 4 × 10 ^-7 A ₁₀ = 0 11th surface K = 0 A ₂ = 0 A ₄ = -1.0160 × 10 ^-3 A ₆ = 4.6636 × 10 ^-6 A ₈ = -1.0 125 × 10 ^-6 A ₁₀ = 0 18th surface K = 0 A ₂ = 0 A ₄ ＝- 9.6507 x 10 ^-5 A ₆ = -5.24 96 x 10 ^-5 A ₈ = 4.9 151 x 10 ^-6 A ₁₀ = 0

When the zoom data D0 (distance from the object to the first surface) is ∞, wide-angle end, middle telephoto end f (mm) 3.25089 5.63716 9.74797 Fno. 2.6146 3.2986 4.4792 D0 ∞ ∞ ∞ D6 0.79869 2.93966 0.79967 D9 9.23582 3.96028 0.89698 D15 3.71237 6.47491 11.24992 D17 1.81385 2.18422 2.61424 D22 1.00000 1.00000 1.00000 D0 (distance from object to first surface) is a short distance (16c)
m) Wide-angle end Mid-telephoto end D0 162.6560 162.6560 162.6560 D6 0.79869 2.93966 0.79967 D9 9.23582 3.96028 0.89698 D15 3.86053 6.90038 12.50997 D17 1.66569 1.75875 1.35418 D22 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, 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
It has a second lens group G2 which is a first moving lens group, an aperture stop S, a third lens group G3 which is a second moving lens group, and a fourth lens group G4. The first lens group G1 is composed of, in order from the object side, a negative meniscus lens L1 ₁ having a convex surface directed toward the object side, a reflective optical element R1 having a reflective surface for bending an optical path, and a biconvex positive lens L1 _2. It has a positive refractive power as a whole. Reflective optical element R1
Is configured as a reflecting 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 biconcave negative lens L2 ₁ and a positive meniscus lens L having a convex surface directed toward the object side.
It is composed of a cemented lens with 2 ₂ and has a negative refracting power as a whole. The third lens group G3 includes, in order from the object side, a cemented lens of a positive meniscus lens L3 ₁ having a convex surface directed toward the object side and a negative meniscus lens L3 ₂ having a convex surface directed toward the object side, and a biconvex positive lens L3 ₃ . It consists of
It has a positive refractive power as a whole. The fourth lens group G4 includes
The double-concave negative lens L4 ₁ ′ and the double-convex positive lens L4 ₂ are cemented together.

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 at the image side. And reciprocate along a convex locus (that is, move to the image side to temporarily widen the distance to the first lens group G1 and then move to the object side to reduce the distance to the first lens group G1), The third lens group G3 moves together with the aperture stop S only toward the object side. Further, when focusing on a short-distance object point, the second lens group G2 is extended toward the object side. The first lens group G1 and the fourth lens group G
The position of No. 4 is fixed even during the focusing operation. The aspherical surface is the image-side surface of the negative meniscus lens L1 ₁ having the convex surface facing the object side in the first lens group G1, and the third lens group G3.
The object-side surface of the positive meniscus lens L3 ₁ having a convex surface directed toward the object side, and the biconvex positive lens L4 _{2 in} the fourth lens group G4.
Is provided on the image-side surface of.

Next, numerical data of optical members constituting the zoom lens of the second embodiment will be shown. Numerical data 2 r ₁ = 26.5948 d ₁ = 0.7000 n _d1 = 1.80610 ν _d1 ＝ 40.92 r ₂ ＝ 5.6908 (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 = 12.8103 d ₅ = 1.7000 n _d5 = 1.72916 ν _d5 ＝ 54.68 r ₆ ＝ -36.8350 d ₆ ＝ D6 r ₇ ＝ -6.9505 d ₇ ＝ 0.7000 n _d7 ＝ 1.69700 ν _d7 ＝ 48.52 r ₈ ＝ 5.0000 d ₈ = 1.5500 n _d8 = 1.84666 ν _d8 = 23.78 r ₉ = 16.5460 d ₉ = D 9 r ₁₀ = ∞ (aperture) d ₁₀ = 0 r ₁₁ = 4.4396 (aspherical surface) d ₁₁ = 1.8000 n _d11 = 1.74320 ν _{d11 = 49.34 r 12 = 19.0000 d 12} = 0.7000 n d12 = 1.84666 ν d12 = 23.78 r 13 = 4.3099 d 13 = 0.3000 r 14 = 7.9340 d 14 = 1.7500 n d14 = 1.72916 ν d14 = 54.68 r 15 = -9.4658 d 15 = D15 r ₁₆ = ∞ (transmittance varying means or shutter arrangement position) d ₁₆ = 4.4000 r ₁₇ = -11.5780 d ₁₇ = 0.7000 n _d17 = 1.80100 ν _d17 = 34.97 r ₁₈ = 20.0000 d ₁₈ = 1.3500 n _d18 = 1.74320 ν _d18 = 49.34 r ₁₉ = -9.3722 (aspherical surface) d ₁₉ = 0.7000 r ₂₀ = ∞ d ₂₀ = 0.6000 n _d20 = 1.51633 ν _d20 = 64.14 r ₂₁ = ∞ d ₂₁ = D21 r ₂₂ = ∞ (imaging plane) d ₂₂ = 0

Aspherical coefficient second surface K = 0 A ₂ = 0 A ₄ = -6.2873 × 10 ⁻⁴ A ₆ = −4.6849 × 10 ⁻⁷ A ₈ = −9.5321 × 10 ⁻⁷ A ₁₀ = 0th 11th surface K = 0 A ₂ = 0 A ₄ = -1.1790 × 10 ^-3 A ₆ = 2.6964 × 10 ^-6 A ₈ = -1.5 144 × 10 ^-6 A ₁₀ = 0 19th surface K = 0 A ₂ = 0 A ₄ = 1.3503 x 10 ^-3 A ₆ = -5.7711 x 10 ^-5 A ₈ = 1.1904 x 10 ^-5 A ₁₀ = 0

When the zoom data D0 (distance from the object to the first surface) is ∞, wide-angle end, middle telephoto end f (mm) 3.26135 5.63695 9.74271 Fno. 2.6987 3.3411 4.5499 D0 ∞ ∞ ∞ ∞ D6 1.09530 3.25443 1.09175 D9 8.94170 3.96767 0.88424 D15 1.39037 4.20559 9.45200 D21 1.00000 1.00000 1.00000 D0 is the short distance (16c)
m) Wide-angle end Mid-telephoto end D0 162.6560 162.6560 162.6560 D6 0.92755 3.08080 0.92401 D9 9.10945 4.14131 1.05198 D15 1.39037 4.20559 9.45200 D21 1.00000 1.00000 1.00000

Third Embodiment FIG. 17 is a sectional view taken along the optical axis showing the optical construction 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.

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, a second lens group G2 that is a first moving lens group, an aperture stop S, and a third lens group G3 that is a second moving lens group.
And has a fourth lens group G4. First lens group G1
Is composed of, in order from the object side, a negative meniscus lens L1 ₁ having a convex surface directed toward the object side, a reflective optical element R1 having a reflecting surface for bending the optical path, and a biconvex positive lens L1 ₂ as a whole. It has a positive refractive power. 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 is composed of, in order from the object side, a cemented lens of a biconcave negative lens L2 ₁ and a positive meniscus lens L2 ₂ having a convex surface facing the object side, and has a negative refracting power as a whole. ing. The third lens group G3 includes, in order from the object side, a positive meniscus lens L3 having a convex surface directed toward the object side.
It is composed of a cemented lens of ₁ and a negative meniscus lens L3 ₂ having a convex surface facing the object side, and a biconvex positive lens L3 _3, and has a positive refracting power as a whole. Fourth lens group G4
Is a negative meniscus lens L4 ₁ ″ with a concave surface facing the object side.
And a positive meniscus lens L4 ₂ ′ with a concave surface facing the object side.

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 at the image side. And reciprocate along a convex locus (that is, move to the image side to temporarily widen the distance to the first lens group G1 and then move to the object side to reduce the distance to the first lens group G1), The third lens group G3 moves together with the aperture stop S only toward the object side. Further, when focusing on a short-distance object point, the second lens group G2 is extended toward the object side. The first lens group G1 and the fourth lens group G
The position of No. 4 is fixed even during the focusing operation. The aspherical surface is the image-side surface of the negative meniscus lens L1 ₁ having the convex surface facing the object side in the first lens group G1, and the third lens group G3.
It is provided on the object-side surface of the positive meniscus lens L3 ₁ whose convex surface faces the object side, and on the image-side surface of the positive meniscus lens L4 ₂ ′ whose concave surface faces the object side in the fourth lens group G4. .

Next, numerical data of optical members constituting the zoom lens of the third embodiment will be shown. Numerical data 3 r ₁ = 23.5093 d ₁ = 0.7000 n _d1 = 1.80100 ν _d1 ＝ 34.97 r ₂ ＝ 5.3202 (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 =} 10.3647 d 5 = 1.7000 n d5 = 1.72916 ν d5 = 54.68 r 6 = -47.4421 d 6 = D6 r 7 = -7.2232 d 7 = 0.7000 n d7 = 1.69680 ν d7 = 55.53 r 8 = 5.0000 d ₈ = 1.5500 n _d8 = 1.84666 ν _d8 = 23.78 r ₉ = 13.6636 d ₉ = D 9 r ₁₀ = ∞ (aperture) d ₁₀ = 0 r ₁₁ = 4.2851 (aspherical surface) d ₁₁ = 1.8000 n _d11 = 1.69350 ν _d11 ＝ 53.21 r ₁₂ ＝ 19.0000 d ₁₂ ＝ 0.7000 n _d12 = 1.84666 ν _d12 ＝ 23.78 r ₁₃ ＝ 4.3542 d ₁₃ ＝ 0.3000 r ₁₄ ＝ 7.5927 d ₁₄ ＝ 1.7500 n _d14 ＝ 1.72916 ν _d14 ＝ 54.68 r ₁₅ ＝ -9.0883 d ₁₅ ＝ D15 r ₁₆ = ∞ (transmittance varying means or shutter arrangement position) d ₁₆ = 4.4000 r ₁₇ = -7.8172 d ₁₇ = 0.7000 n _d17 = 1.84666 ν _d17 = 23.78 r ₁₈ = -50.0000 d ₁₈ = 1.3500 n _d18 = 1.74320 ν _d18 = 49.34 r ₁₉ = -7.2821 (aspherical surface) d ₁₉ = 0.7000 r ₂₀ = ∞ d ₂₀ = 0.6000 n _d20 = 1.51633 ν _d20 = 64.14 r ₂₁ = ∞ d ₂₁ = D21 r ₂₂ = ∞ (imaging plane) d ₂₂ = 0

Aspheric coefficient 2nd surface K = 0 A ₂ = 0 A ₄ = -7.4556 × 10 ^-4 A ₆ = 3.8977 × 10 ^-6 A ₈ = -1.6059 × 10 ^-6 A ₁₀ = 0 11th surface K = 0 A ₂ = 0 A ₄ = -1.4222 × 10 ^-3 A ₆ = -8.4545 × 10 ^-7 A ₈ = -1.7364 × 10 ^-6 A ₁₀ = 0 19th surface K = 0 A ₂ = 0 A ₄ = 1.5497 x 10 ^-3 A ₆ = -1.9296 x 10 ^-4 A ₈ = 3.0021 x 10 ^-5 A ₁₀ = 0

When the zoom data D0 (distance from the object to the first surface) is ∞, wide-angle end, middle telephoto end f (mm) 3.26990 5.62502 9.73871 Fno. 2.7015 3.2638 4.4073 D0 ∞ ∞ ∞ D6 1.09108 3.56834 1.99910 D9 9.07726 4.16755 0.88213 D15 1.21117 3.63605 8.49846 D21 1.00000 1.00000 1.00000 D0 (distance from object to first surface) is short distance (16c
m) Wide-angle end Mid-telephoto end D0 162.6560 162.6560 162.6560 D6 0.92058 3.38281 1.82331 D9 9.24776 4.35308 1.05792 D15 1.21117 3.63605 8.49846 D21 1.00000 1.00000 1.00000

Fourth Embodiment FIG. 19 is a sectional view taken along the optical axis showing the optical construction of a fourth 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. 20 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens according to Example 4 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. 21 to 23 are diagrams showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification when the zoom lens according to Example 4 is focused on an object point at infinity. FIG. 21 is a wide angle end, and FIG. In the middle, FIG. 23 shows the state at the telephoto end. 24 to 26 are diagrams showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 4 upon focusing on an object point at a short distance,
FIG. 24 shows the state at the wide-angle end, FIG. 25 shows the state at the middle, and FIG. 26 shows the state at the telephoto end.

As shown in FIG. 19, the electronic image pickup apparatus of the fourth embodiment has a zoom lens and a CCD which is an electronic image pickup element in order from the object side. In FIG. 19, 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, a second lens group G2 that is a first moving lens group, an aperture stop S, and a third lens group G3 that is a second moving lens group.
And has a fourth lens group G4. First lens group G1
Is composed of, in order from the object side, a negative meniscus lens L1 ₁ having a convex surface directed toward the object side, a reflective optical element R1 having a reflecting surface for bending the optical path, and a biconvex positive lens L1 ₂ as a whole. It has a positive refractive power. 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 is composed of, in order from the object side, a cemented lens of a biconcave negative lens L2 ₁ and a positive meniscus lens L2 ₂ having a convex surface facing the object side, and has a negative refracting power as a whole. ing. The third lens group G3 includes, in order from the object side, a positive meniscus lens L3 having a convex surface directed toward the object side.
It is composed of a cemented lens of ₁ and a negative meniscus lens L3 ₂ having a convex surface facing the object side, and a biconvex positive lens L3 _3, and has a positive refracting power as a whole. Fourth lens group G4
Is a positive meniscus lens L having a concave surface facing the object side.
It is composed of 4 ₁ "'.

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 on the image side. And reciprocate along a convex locus (that is, move to the image side to temporarily widen the distance to the first lens group G1 and then move to the object side to reduce the distance to the first lens group G1), The third lens group G3 moves together with the aperture stop S only toward the object side. Further, when focusing on a short-distance object point, the second lens group G2 is extended toward the object side. The first lens group G1 and the fourth lens group G
The position of No. 4 is fixed even during the focusing operation. The aspherical surface is the image-side surface of the negative meniscus lens L1 ₁ having the convex surface facing the object side in the first lens group G1, and the third lens group G3.
Provided on the object-side surface of the positive meniscus lens L3 ₁ having a convex surface facing the object side, and on the image-side surface of the positive meniscus lens L4 ₁ ″ ′ having a concave surface facing the object side that constitutes the fourth lens group G4. ing.

Next, numerical data of optical members constituting the zoom lens of the fourth embodiment will be shown. Numerical data 4 r ₁ = 29.7756 d ₁ = 0.7000 n _d1 = 1.80610 ν _d1 ＝ 40.92 r ₂ = 5.5894 (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 =} 12.5603 d 5 = 1.7500 n d5 = 1.72916 ν d5 = 54.68 r 6 = -28.7102 d 6 = D6 r 7 = -7.7962 d 7 = 0.7000 n d7 = 1.69700 ν d7 = 48.52 r 8 = 5.0000 d ₈ = 1.6000 n _d8 = 1.84666 ν _d8 = 23.78 r ₉ = 15.2398 d ₉ = D 9 r ₁₀ = ∞ (aperture) d ₁₀ = 0 r ₁₁ = 4.2660 (aspheric) d ₁₁ = 1.8000 n _d11 = 1.74320 ν _{d11 = 49.34 r 12 = 17.0000 d 12} = 0.7000 n d12 = 1.84666 ν d12 = 23.78 r 13 = 3.9877 d 13 = 0.3000 r 14 = 7.3491 d 14 = 1.7000 n d14 = 1.72916 ν d14 = 54.68 r 15 = -11.3337 d 15 = 0.9338 r ₁₆ = ∞ (variable transmittance means or shutter _{position) d 16 = 5.4000 r 17 =} -20.8118 d 17 = 1.0000 n d17 = 1.58313 ν d17 = 59.38 r 18 = -11.2032 _{Aspherical) d 18 = 0.7000 r 19 =} ∞ d 19 = 0.6000 n d19 = 1.51633 ν d19 = 64.14 r 20 = ∞ d 20 = D20 r 22 = ∞ ( imaging plane) d ₂₂ = 0

Aspherical coefficient second surface K = 0 A ₂ = 0 A ₄ = -6.3979 × 10 ^-4 A ₆ = -7.5270 × 10 ^-7 A ₈ = -9.7517 × 10 ^-7 A ₁₀ = 0 11th surface K = 0 A ₂ = 0 A ₄ = -1.0377 × 10 ^-3 A ₆ = -2.4735 × 10 ^-6 A ₈ = -2.0035 × 10 ^-6 A ₁₀ = 0 18th surface K = 0 A ₂ = 0 A ₄ = 1.1850 x 10 ^-3 A ₆ = 1.2885 x 10 ^-4 A ₈ = -1.2384 x 10 ^-5 A ₁₀ = 0

When the zoom data D0 (distance from the object to the first surface) is ∞, wide-angle end middle telephoto end f (mm) 3.25682 5.63853 9.74463 Fno. 2.6426 3.2679 4.5140 D0 ∞ ∞ ∞ D6 1.09607 3.39481 1.09365 D9 9.37627 4.21600 0.88753 D15 0.93379 3.79716 9.42548 D21 1.00000 1.00000 1.00000 D0 is the short distance (16c)
m) Wide-angle end Mid-telephoto end D0 162.6560 162.6560 162.6560 D6 0.89495 3.18037 0.89254 D9 9.57739 4.43044 1.08864 D15 0.93379 3.79716 9.42548 D21 1.00000 1.00000 1.00000

Fifth Embodiment FIG. 27 is a sectional view taken along the optical axis showing the optical configuration of a zoom lens used in an electronic image pickup apparatus according to the fifth embodiment of the present invention. The state at the time of bending is shown. FIG. 28 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens according to the fifth 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. 29 to 31 are diagrams showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification when the zoom lens according to Example 5 is focused on an object point at infinity. FIG. 29 is a wide angle end, and FIG. In the middle, FIG. 31 shows the state at the telephoto end. 32 to 34 are diagrams showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to the fifth example upon focusing on an object point at a short distance,
32 shows the state at the wide-angle end, FIG. 33 at the middle, and FIG. 34 at the telephoto end.

As shown in FIG. 27, the electronic image pickup apparatus of the fifth embodiment has, in order from the object side, a zoom lens and a CCD which is an electronic image pickup element. In FIG. 27, 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, a second lens group G2 that is a first moving lens group, an aperture stop S, and a third lens group G3 that is a second moving lens group.
And has a fourth lens group G4. First lens group G1
Is composed of, in order from the object side, a negative meniscus lens L1 ₁ having a convex surface directed toward the object side, a reflective optical element R1 having a reflecting surface for bending the optical path, and a biconvex positive lens L1 ₂ as a whole. It has a positive refractive power. 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 is composed of, in order from the object side, a cemented lens of a biconcave negative lens L2 ₁ and a positive meniscus lens L2 ₂ having a convex surface facing the object side, and has a negative refracting power as a whole. ing. The third lens group G3 includes, in order from the object side, a positive meniscus lens L3 having a convex surface directed toward the object side.
It is composed of a cemented lens of ₁ and a negative meniscus lens L3 ₂ having a convex surface facing the object side, and a biconvex positive lens L3 _3, and has a positive refracting power as a whole. Fourth lens group G4
Is a negative meniscus lens L4 ₁ ″ with a concave surface facing the object side.
And a positive meniscus lens L4 ₂ ′ with a concave surface facing the object side.

When zooming from the wide-angle end to the telephoto end when focusing on an object point at infinity, the position of the first lens group G1 is fixed, and the second lens group G2 moves only to the image side. The third lens group G3 moves only to the object side together with the aperture stop S, and the fourth lens group G4 reciprocates to the image side in a concave locus (that is,
After moving to the object side to temporarily widen the distance to the CCD cover glass CG, the distance to the CCD cover glass CG is reduced while moving to the object side). Also,
When focusing on a short-distance object point, the second lens group G
2 is extended to the object side. The positions of the first lens group G1 and the fourth lens group G4 are fixed during the focusing operation. The aspherical surface is the first lens group G
Negative meniscus lens L1 ₁ with the convex surface facing the object side in ₁
Image-side surface, the object-side surface of the positive meniscus lens L3 ₁ having a convex surface facing the object side in the third lens group G3, and the positive meniscus lens L having a concave surface facing the object side in the fourth lens group G4
It is provided on the image side of 4 ₂ '.

Next, numerical data of optical members constituting the zoom lens of the fifth embodiment will be shown. Numerical data 5 r ₁ = 18.8862 d ₁ = 0.7000 n _d1 = 1.80100 ν _d1 ＝ 34.97 r ₂ ＝ 4.8033 (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 =} 13.4964 d 5 = 2.3000 n d5 = 1.61800 ν d5 = 63.33 r 6 = -11.1385 d 6 = D6 r 7 = -8.8071 d 7 = 0.7000 n d7 = 1.69680 ν d7 = 55.53 r 8 = 4.9069 d ₈ = 1.5500 n _d8 = 1.84666 ν _d8 = 23.78 r ₉ = 9.5429 d ₉ = D 9 r ₁₀ = ∞ (aperture) d ₁₀ = 0 r ₁₁ = 4.0853 (aspherical surface) d ₁₁ = 1.8000 n _d11 = 1.69350 ν _d11 = 53.21 r ₁₂ = 11.0960 d ₁₂ = 0.7000 n _d12 = 1.84666 ν _d12 ＝ 23.78 r ₁₃ ＝ 3.9813 d ₁₃ ＝ 0.3000 r ₁₄ ＝ 5.9541 d ₁₄ ＝ 1.9500 n _d14 = 1.72916 ν _d14 ＝ 54.68 r ₁₅ ＝ -9.8112 d ₁₅ D15 r ₁₆ = ∞ (transmittance varying means or shutter arrangement position) d ₁₆ = D16 r ₁₇ = -3.5444 d ₁₇ = 0.7000 n _d17 = 1.84666 ν _d17 = 23.78 r ₁₈ = -10.000 0 d ₁₈ = 1.3500 n _d18 = 1.74320 ν _d18 = 49.34 r ₁₉ = -4.2449 (aspherical surface) d ₁₉ = D19 r ₂₀ = ∞ d ₂₀ = 0.6000 n _d20 = 1.51633 ν _d20 = 64.14 r ₂₁ = ∞ d ₂₁ = D 21 r ₂₂ = ∞ (imaging surface) d ₂₂ = 0

Aspheric coefficient second surface K = 0 A ₂ = 0 A ₄ = -5.1721 × 10 ^-4 A ₆ = -1.0392 × 10 ^-6 A ₈ = -2.0432 × 10 ^-6 A ₁₀ = 0 11th surface K = 0 A ₂ = 0 A ₄ = -1.4943 × 10 ^-3 A ₆ = -5.7721 × 10 ^-6 A ₈ = -3.1513 × 10 ^-6 A ₁₀ = 0 19th surface K = 0 A ₂ = 0 A ₄ = 4.5325 x 10 ^-4 A ₆ = 2.3664 x 10 ^-4 A ₈ = -1.3755 x 10 ^-5 A ₁₀ = 0

When the zoom data D0 (distance from the object to the first surface) is ∞, wide-angle end middle telephoto end f (mm) 3.29281 5.63775 9.72059 Fno. 2.7263 3.1514 3.8592 D0 ∞ ∞ ∞ ∞ D6 1.08448 3.76500 4.99556 D9 9.23562 4.42709 0.86778 D15 0.70863 2.83776 5.16580 D16 3.84796 2.38541 3.84796 D19 0.89838 2.35813 0.88807 D21 1.00000 1.00000 1.00000 D0 (distance from the 1st surface to the 1st surface)
m) Wide-angle end Mid-telephoto end D0 162.6560 162.6560 162.6560 D6 0.89908 3.53214 4.73441 D9 9.42102 4.65996 1.12893 D15 0.70863 2.83776 5.16580 D16 3.84796 2.38541 3.85876 D19 0.89838 2.35813 0.88807 D21 1.00000 1.00000 1.00000

Sixth Embodiment FIG. 35 is a sectional view taken along the optical axis showing the optical structure of a zoom lens used in the electronic image pickup apparatus according to the sixth embodiment of the present invention. The state at the time of bending is shown. FIG. 36 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens according to Example 6 when focused on an object point at infinity. (A) is the wide-angle end, (b) is the middle, and (c) is the It shows the state at the telephoto end. 37 to 39 are diagrams showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 6 upon focusing on an object point at infinity. FIG. 37 is a wide angle end, and FIG. In the middle, FIG. 39 shows the state at the telephoto end. 40 to 42 are diagrams showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 6 upon focusing on an object point at a short distance,
40 shows the state at the wide-angle end, FIG. 41 shows the state at the middle, and FIG. 42 shows the state at the telephoto end.

As shown in FIG. 35, the electronic image pickup apparatus according to the sixth embodiment has, in order from the object side, a zoom lens and a CCD which is an electronic image pickup element. In FIG. 35, 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, a second lens group G2 that is a first moving lens group, an aperture stop S, and a third lens group G3 that is a second moving lens group.
And has a fourth lens group G4. First lens group G1
Is a negative meniscus lens L1 ₁ having a convex surface facing the object side, a reflective optical element R1 having a reflecting surface for bending the optical path, and a positive meniscus lens L1 ₂ ′ having a convex surface facing the object side in order from the object side. It has a positive refracting power as a whole. The reflective optical element R1 has an optical path of 90 °.
It is constructed as a folding prism. In addition,
The aspect ratio of the effective imaging area in each embodiment of the present invention is 3:
4 and the bending direction is the lateral direction. The second lens group G2 is composed of, in order from the object side, a cemented lens of a biconcave negative lens L2 ₁ and a positive meniscus lens L2 ₂ having a convex surface facing the object side, and has a negative refracting power as a whole. ing.
The third lens group G3 includes, in order from the object side, a biconvex positive lens L
3 ₁ 'and a positive meniscus lens L with a convex surface facing the object side
3 ₂ 'and negative meniscus lens L with convex surface facing the object side
3 ₃ is composed of a cemented lens of a ', and has a positive refractive power as a whole. The fourth lens group G4 is composed of a positive meniscus lens L4 ₁ ″ ′ with a concave surface facing the object side.

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 at the image side. And reciprocate along a convex locus (that is, move to the image side to temporarily widen the distance to the first lens group G1 and then move to the object side to reduce the distance to the first lens group G1), The third lens group G3 moves together with the aperture stop S only toward the object side. Further, when focusing on a short-distance object point, the second lens group G2 is extended toward the object side. The first lens group G1 and the fourth lens group G
The position of No. 4 is fixed even during the focusing operation. The aspherical surface is the image-side surface of the negative meniscus lens L1 ₁ having the convex surface facing the object side in the first lens group G1, and the third lens group G3.
It is provided on the object side surface of the biconvex positive lens L3 ₁ ′ and on the image side surface of the positive meniscus lens L4 ₁ ″ ′ with the concave surface facing the object side forming the fourth lens group G4.

Next, numerical data of optical members constituting the zoom lens of the sixth embodiment will be shown. Numerical data 6 r ₁ = 39.8371 d ₁ = 0.9000 n _d1 = 1.74320 ν _d1 ＝ 49.34 r ₂ ＝ 7.0363 (aspherical surface) d ₂ ＝ 1.9500 r ₃ ＝ ∞ d ₃ ＝ 8.4000 n _d3 = 1.80610 ν _d3 ＝ 40.92 r ₄ ＝ _{∞ d 4 = 0.1500 r 5 =} 10.7443 d 5 = 1.7500 n d5 = 1.72916 ν d5 = 54.68 r 6 = 117.6949 d 6 = D6 r 7 = -11.0080 d 7 = 0.7000 n d7 = 1.72916 ν d7 = 54.68 r 8 = 10.0000 d ₈ = 1.3500 n _d8 = 1.84666 v _d8 = 23.78 r ₉ = 29.9687 d ₉ = D 9 r ₁₀ = ∞ (diaphragm) d ₁₀ = 0 r ₁₁ = 8.9151 d ₁₁ = 1.7000 n _d11 = 1.58313 ν _d11 = 59.38 r ₁₂ = -9.9490 (aspherical surface) d ₁₂ = 0.1500 r ₁₃ = 3.8299 d ₁₃ = 1.9500 n _d13 = 1.69350 ν _d13 = 53.21 r ₁₄ = 40.0000 d ₁₄ = 0.7000 n _d14 = 1.78740 ν _d14 = 26.29 r ₁₅ = 2.5278 d ₁₅ = 1.6250 r ₁₆ = ∞ (variable transmittance means or shutter _{position) d 16 = D16 r 17 =} -75.2976 d 17 = 1.6000 n d17 = 1.68893 ν d17 = 31.07 r 18 = -6.956 7 (aspherical surface) d ₁₈ = 0.6000 r ₁₉ = ∞ d ₁₉ = 0.7500 n _d19 = 1.51633 ν _d19 = 64.14 r ₂₀ = ∞ d ₂₀ = D 20 r ₂₁ = ∞ (imaging surface) d ₂₁ = 0

Aspheric coefficient 2nd surface K = 0 A ₂ = 0 A ₄ = -3.2095 × 10 ⁻⁴ A ₆ = 3.5914 × 10 ⁻⁶ A ₈ = −2.3288 × 10 ⁻⁷ A ₁₀ = 0 12th surface K = 0 A ₂ = 0 A ₄ = 7.8959 × 10 ^-4 A ₆ ＝ -8.1489 × 10 ^-6 A ₈ ＝ 8.1947 × 10 ^-7 A ₁₀ = 0 18th surface K = 0 A ₂ = 0 A ₄ ＝ 1.5904 × 10 ^-3 A ₆ = -7.4738 x 10 ^-5 A ₈ = 1.6824 x 10 ^-6 A ₁₀ = 0

When the zoom data D0 (distance from the object to the first surface) is ∞, wide-angle end, middle telephoto end f (mm) 4.00704 6.93144 11.99933 Fno. 2.6299 3.4603 5.0206 D0 ∞ ∞ ∞ ∞ D6 1.33984 3.55821 1.33955 D9 8.82987 3.72328 0.59893 D16 2.39220 5.27920 10.62359 D20 1.00000 1.00000 1.00000 D0 is the short distance (20c)
m) Wide-angle end Mid-telephoto end D0 200.0000 200.0000 200.0000 D6 0.99920 3.20721 0.99891 D9 9.17052 4.07428 0.93957 D16 2.39220 5.27920 10.62359 D20 1.00000 1.00000 1.00000

Seventh Embodiment FIG. 43 is a sectional view taken along the optical axis showing the optical configuration of a zoom lens used in an electronic image pickup apparatus according to the seventh embodiment of the present invention. The state at the time of bending is shown. FIG. 44 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens of Example 7 when focused on an object point at infinity. (A) is the wide-angle end, (b) is the middle, and (c) is the It shows the state at the telephoto end.

As shown in FIG. 43, the electronic image pickup apparatus according to the seventh embodiment has, in order from the object side, a zoom lens and a CCD which is an electronic image pickup element. In FIG. 43, 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, a second lens group G2 that is a first moving lens group, an aperture stop S, and a third lens group G3 that is a second moving lens group.
And has a fourth lens group G4. First lens group G1
Is a negative meniscus lens L1 ₁ having a convex surface facing the object side, a reflective optical element R1 having a reflecting surface for bending the optical path, and a positive meniscus lens L1 ₂ ′ having a convex surface facing the object side in order from the object side. It has a positive refracting power as a whole. The reflective optical element R1 has an optical path of 90 °.
It is constructed as a folding prism. In addition,
The aspect ratio of the effective imaging area in each embodiment of the present invention is 3:
4 and the bending direction is the lateral direction. The second lens group G2 is composed of, in order from the object side, a cemented lens of a biconcave negative lens L2 ₁ and a positive meniscus lens L2 ₂ having a convex surface facing the object side, and has a negative refracting power as a whole. ing.
The third lens group G3 includes, in order from the object side, a biconvex positive lens L
3 ₁ 'and a positive meniscus lens L with a convex surface facing the object side
3 ₂ 'and negative meniscus lens L with convex surface facing the object side
3 ₃ is composed of a cemented lens of a ', and has a positive refractive power as a whole. The fourth lens group G4 is composed of a positive meniscus lens L4 ₁ ″ ′ with a concave surface facing the object side.

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 at the image side. And reciprocate along a convex locus (that is, move to the image side to temporarily widen the distance to the first lens group G1 and then move to the object side to reduce the distance to the first lens group G1), The third lens group G3 moves together with the aperture stop S only toward the object side. Further, when focusing on a short-distance object point, the second lens group G2 is extended toward the object side. The first lens group G1 and the fourth lens group G
The position of No. 4 is fixed even during the focusing operation. The aspherical surface is the image-side surface of the negative meniscus lens L1 ₁ having the convex surface facing the object side in the first lens group G1, and the third lens group G3.
A positive meniscus lens L3 ₂ with a convex surface on the object side in the '
Of the positive meniscus lens L4 ₁ ″ ′ having a concave surface facing the object side of the fourth lens group G4.

Next, numerical data of optical members constituting the zoom lens of the seventh embodiment will be shown. Numerical data 7 r ₁ = 46.4345 d ₁ = 0.9000 n _d1 = 1.74320 ν _d1 = 49.34 r ₂ = 7.4800 (aspherical surface) d ₂ = 1.9000 r ₃ = ∞ d ₃ = 8.4000 n _d3 = 1.80610 ν _d3 = 40.92 r ₄ = _{∞ d 4 = 0.1500 r 5 =} 10.9290 d 5 = 1.7000 n d5 = 1.72916 ν d5 = 54.68 r 6 = 79.8760 d 6 = D6 r 7 = -9.0602 d 7 = 0.7000 n d7 = 1.72916 ν d7 = 54.68 r 8 = 10.0000 d ₈ = 1.3500 n _d8 = 1.80518 ν _d8 ＝ 25.42 r ₉ ＝ 79.0547 d ₉ ＝ D 9 r ₁₀ ＝ ∞ (diaphragm) d ₁₀ ＝ 0 r ₁₁ ＝ 12.8072 d ₁₁ = 1.8000 n _d11 = 1.48749 ν _d11 ＝ 70.23 r ₁₂ ＝ -7.7890 d ₁₂ = 0.1500 r ₁₃ = 3.3563 (aspherical surface) d ₁₃ = 2.0000 n _d13 = 1.74320 ν _d13 = 49.34 r ₁₄ = 10.000 d ₁₄ = 0.7000 n _d14 = 1.84666 ν _d14 = 23.78 r ₁₅ = 2.3358 d ₁₅ = 1.6250 r ₁₆ = ∞ (transmittance varying means or shutter arrangement position) d ₁₆ = D16 r ₁₇ = -32.6186 d ₁₇ = 1.6000 n _d17 = 1.68893 ν _d17 = 31.07 r ₁₈ = -6.3725 (Aspherical surface) d ₁₈ = 0.6000 r ₁₉ = ∞ d ₁₉ = 0.7500 n _d19 = 1.51633 ν _d19 = 64.14 r ₂₀ = ∞ d ₂₀ = D 20 r ₂₁ = ∞ (imaging surface) d ₂₁ = 0

Aspheric coefficient 2nd surface K = 0 A ₂ = 0 A ₄ = -3.0741 × 10 ^-4 A ₆ = 2.9868 × 10 ^-6 A ₈ = -2.2074 × 10 ^-7 A ₁₀ = 0 13th surface K = 0 A ₂ = 0 A ₄ = -8.6447 × 10 ^-4 A ₆ = -2.3383 × 10 ^-5 A ₈ = -1.1764 × 10 ^-5 A ₁₀ = 0 18th surface K = 0 A ₂ = 0 A ₄ = 1.7917 × 10 ^-3 A ₆ = -8.0 795 × 10 ^-5 A ₈ = 2.0929 × 10 ^-6 A ₁₀ = 0

When the zoom data D0 (distance from the object to the first surface) is ∞, wide-angle end, middle telephoto end f (mm) 4.00365 6.92795 12.00080 Fno. 2.6033 3.4480 5.0024 D0 ∞ ∞ ∞ D6 1.32737 3.52064 1.32840 D9 8.76178 3.65332 0.60135 D16 2.39254 5.30046 10.55195 D20 1.00000 1.00000 1.00000 D0 is the short distance (20c)
m) Wide-angle end Mid-telephoto end D0 200.0000 200.0000 200.0000 D6 0.99975 3.18799 1.00078 D9 9.08940 3.98598 0.92898 D16 2.39254 5.30046 10.55195 D20 1.00000 1.00000 1.00000

Eighth Embodiment FIG. 45 is a sectional view taken along the optical axis showing the optical construction of a zoom lens used in the electronic image pickup apparatus according to the eighth embodiment of the present invention. The state at the time of bending is shown. FIG. 46 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens according to Example 8 upon focusing on an object point at infinity. (A) is the wide-angle end, (b) is the middle, and (c) is the It shows the state at the telephoto end.

As shown in FIG. 45, the electronic image pickup apparatus of the eighth embodiment has, in order from the object side, a zoom lens and a CCD which is an electronic image pickup element. In FIG. 45, 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, a second lens group G2 that is a first moving lens group, an aperture stop S, and a third lens group G3 that is a second moving lens group.
And has a fourth lens group G4. First lens group G1
Is a negative meniscus lens L1 ₁ having a convex surface facing the object side, a reflective optical element R1 having a reflecting surface for bending the optical path, and a positive meniscus lens L1 ₂ ′ having a convex surface facing the object side in order from the object side. It has a positive refracting power as a whole. The reflective optical element R1 has an optical path of 90 °.
It is constructed as a folding prism. In addition,
The aspect ratio of the effective imaging area in each embodiment of the present invention is 3:
4 and the bending direction is the lateral direction. The second lens group G2 is composed of, in order from the object side, a cemented lens of a biconcave negative lens L2 ₁ and a positive meniscus lens L2 ₂ having a convex surface facing the object side, and has a negative refracting power as a whole. ing.
The third lens group G3 includes, in order from the object side, a biconvex positive lens L
3 ₁ 'and a positive meniscus lens L with a convex surface facing the object side
3 ₂ 'and negative meniscus lens L with convex surface facing the object side
3 ₃ is composed of a cemented lens of a ', and has a positive refractive power as a whole. The fourth lens group G4 is composed of a positive meniscus lens L4 ₁ ″ ′ with a concave surface facing the object side.

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 at the image side. And reciprocate along a convex locus (that is, move to the image side to temporarily widen the distance to the first lens group G1 and then move to the object side to reduce the distance to the first lens group G1), The third lens group G3 moves together with the aperture stop S only toward the object side. Further, when focusing on a short-distance object point, the second lens group G2 is extended toward the object side. The first lens group G1 and the fourth lens group G
The position of No. 4 is fixed even during the focusing operation. The aspherical surface is the image-side surface of the negative meniscus lens L1 ₁ having the convex surface facing the object side in the first lens group G1, and the third lens group G3.
It is provided on the object side surface of the biconvex positive lens L3 ₁ ′ and on the image side surface of the positive meniscus lens L4 ₁ ″ ′ with the concave surface facing the object side forming the fourth lens group G4.

Next, numerical data of optical members constituting the zoom lens of the eighth embodiment will be shown. Numerical data 8 r ₁ = 39.9121 d ₁ = 0.9000 n _d1 = 1.74320 ν _d1 ＝ 49.34 r ₂ ＝ 7.0006 (aspherical surface) d ₂ ＝ 1.9500 r ₃ ＝ ∞ d ₃ ＝ 8.4000 n _d3 = 1.80610 ν _d3 ＝ 40.92 r ₄ ＝ _{∞ d 4 = 0.1500 r 5 =} 10.6090 d 5 = 1.7500 n d5 = 1.72916 ν d5 = 54.68 r 6 = 147.0043 d 6 = D6 r 7 = -10.9916 d 7 = 0.7000 n d7 = 1.72916 ν d7 = 54.68 r 8 = 10.0000 d ₈ = 1.3500 n _d8 = 1.84666 ν _d8 ＝ 23.78 r ₉ ＝ 28.2731 d ₉ ＝ D 9 r ₁₀ ＝ ∞ (aperture) d ₁₀ = 0 r ₁₁ ＝ 9.1551 (aspherical face) d ₁₁ = 1.7000 n _d11 = 1.58313 ν _d11 ＝ 59.38 r ₁₂ = -9.4402 d ₁₂ = 0.1500 r ₁₃ = 3.8548 d ₁₃ = 1.9500 n _d13 = 1.69350 v _d13 = 53.21 r ₁₄ = 40.0000 d ₁₄ = 0.7000 n _d14 = 1.78470 v _d14 = 26.29 r ₁₅ = 2.5225 d ₁₅ = D15 r ₁₆ = ∞ (transmittance varying means or shutter arrangement position) d ₁₆ = 2.8250 r ₁₇ = -85.1906 d ₁₇ = 1.6000 n _d17 = 1.68893 ν _d17 = 31.07 r ₁₈ = -7.005 7 (aspherical surface) d ₁₈ = 0.6000 r ₁₉ = ∞ d ₁₉ = 0.7500 n _d19 = 1.51633 ν _d19 = 64.14 r ₂₀ = ∞ d ₂₀ = D 20 r ₂₁ = ∞ (imaging surface) d ₂₁ = 0

Aspheric coefficient 2nd surface K = 0 A ₂ = 0 A ₄ = -3.2240 × 10 ^-4 A ₆ = 3.7049 × 10 ^-6 A ₈ = -2.5408 × 10 ^-7 A ₁₀ = 0 11th surface K = 0 A ₂ = 0 A ₄ = -7.8694 x 10 ^-4 A ₆ = 5.1170 x 10 ^-6 A ₈ = -2.0804 x 10 ^-7 A ₁₀ = 0 18th surface K = 0 A ₂ = 0 A ₄ = 1.5375 X 10 ^-3 A ₆ = -6.5569 x 10 ^-5 A ₈ = 1.0698 x 10 ^-6 A ₁₀ = 0

When the zoom data D0 (distance from the object to the first surface) is ∞, wide-angle end, middle telephoto end f (mm) 4.00716 6.92905 12.00056 Fno. 2.6214 3.4396 5.0196 D0 ∞ ∞ ∞ D6 1.34278 3.57165 1.34265 D9 8.82741 3.75134 0.59749 D15 1.18816 4.03385 9.41834 D20 1.00000 1.00000 1.00000 D0 is the short distance (20c)
m) Wide-angle end Mid-telephoto end D0 200.0000 200.0000 200.0000 D6 0.99949 3.21410 0.99936 D9 9.17070 4.10889 0.94079 D15 1.18816 4.03385 9.41834 D20 1.00000 1.00000 1.00000

Ninth Embodiment FIG. 47 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 ninth embodiment of the present invention. The state at the time of bending is shown. 48 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens of Example 9 when focused on an object point at infinity, where (a) is the wide-angle end, (b) is the middle, and (c) is the It shows the state at the telephoto end. 49 to 51 are diagrams showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens according to the ninth example upon focusing on an object point at infinity. FIG. 49 shows a wide angle end, and FIG. In the middle, FIG. 51 shows the state at the telephoto end. 52 to 54 are diagrams showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to the ninth example upon focusing on an object point at a short distance,
52 shows the state at the wide-angle end, FIG. 53 at the middle, and FIG. 54 at the telephoto end.

As shown in FIG. 47, the electronic image pickup apparatus according to the ninth embodiment has, in order from the object side, a zoom lens and a CCD which is an electronic image pickup element. In FIG. 47, 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, a second lens group G2 that is a first moving lens group, an aperture stop S, and a third lens group G3 that is a second moving lens group.
And has a fourth lens group G4. First lens group G1
Is composed of, in order from the object side, a negative meniscus lens L1 ₁ having a convex surface directed toward the object side, a reflective optical element R1 having a reflecting surface for bending the optical path, and a biconvex positive lens L1 ₂ as a whole. It has a positive refractive power. 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 is composed of, in order from the object side, a cemented lens of a biconcave negative lens L2 ₁ and a positive meniscus lens L2 ₂ having a convex surface facing the object side, and has a negative refracting power as a whole. ing. The third lens group G3 includes, in order from the object side, a biconvex positive lens L3 ₁ ′, a positive meniscus lens L3 ₂ ′ whose convex surface faces the object side, and a negative meniscus lens L3 ₃ ′ whose convex surface faces the object side. It is composed of a cemented lens and has a positive refracting power as a whole. The fourth lens group G4 is a positive meniscus lens L having a convex surface directed toward the object side.
4 ₁ ″ ”and a negative lens L 4 ₂ ″ having a concave surface on the object side and a flat surface on the image side.

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 at the image side. And reciprocate along a convex locus (that is, move to the image side to temporarily widen the distance to the first lens group G1 and then move to the object side to reduce the distance to the first lens group G1), The third lens group G3 moves together with the aperture stop S only toward the object side. Further, when focusing on a short-distance object point, the second lens group G2 is extended toward the object side. The first lens group G1 and the fourth lens group G
The position of No. 4 is fixed even during the focusing operation. The aspherical surface is the image-side surface of the negative meniscus lens L1 ₁ having the convex surface facing the object side in the first lens group G1, and the third lens group G3.
An object-side surface of the biconvex positive lens L3 ₁ ′, a positive meniscus lens L4 having a convex surface directed toward the object side in the fourth lens group G4.
_{It is provided} on the object-side surface of ₁ "" and on the object-side surface of a negative lens L4 ₂ "having a concave surface on the object side and a flat surface on the image side.

Next, numerical data of optical members constituting the zoom lens of the ninth embodiment will be shown. Numerical data 9 r ₁ = 31.8167 d ₁ = 0.9000 n _d1 = 1.74320 ν _d1 ＝ 49.34 r ₂ ＝ 6.5130 (aspherical surface) d ₂ ＝ 2.0500 r ₃ ＝ ∞ d ₃ ＝ 8.4000 n _d3 = 1.80610 ν _d3 ＝ 40.92 r ₄ ＝ _{∞ d 4 = 0.1500 r 5 =} 12.2002 d 5 = 1.7500 n d5 = 1.72916 ν d5 = 54.68 r 6 = -176.2299 d 6 = D6 r 7 = -12.2304 d 7 = 0.7000 n d7 = 1.72916 ν d7 = 54.68 r 8 = 11.5000 d ₈ = 1.3500 n _d8 = 1.84666 ν _d8 = 23.78 r ₉ = 32.1701 d ₉ = D 9 r ₁₀ = ∞ (aperture) d ₁₀ = 0 r ₁₁ = 12.3535 (aspherical surface) d ₁₁ = 1.7000 n _d11 = 1.58313 ν _d11 = 59.38 r ₁₂ = -9.7878 d ₁₂ = 0.1500 r ₁₃ = 4.1265 d ₁₃ = 1.9500 n _d13 = 1.69350 ν _d13 = 53.21 r ₁₄ = 22.0000 d ₁₄ = 0.7000 n _d14 = 1.78470 ν _d14 = 26.29 r ₁₅ = 2.9294 d ₁₅ D15 r ₁₆ = 10.1130 (aspherical surface) d ₁₆ = 1.4500 n _d16 = 1.58313 ν _d16 = 59.38 r ₁₇ = 2083.7929 d ₁₇ = D17 r ₁₈ = -216.5126 (aspherical surface) d ₁₈ = 0.9000 n _d18 = 1.52542 v _d18 = 55.78 r ₁₉ = ∞ d ₁₉ = 0.6000 r ₂₀ = ∞ d ₂₀ = 0.7500 n _d20 = 1.51633 v _d20 = 64.14 r ₂₁ = ∞ d ₂₁ = D 21 r ₂₂ = ∞ (imaging plane) d ₂₂ = 0

Aspheric coefficient 2nd surface K = 0 A ₂ = 0 A ₄ = -4.7792 × 10 ^-4 A ₆ = 8.5290 × 10 ^-6 A ₈ = -4.3636 × 10 ^-7 A ₁₀ = 0 11th surface K = 0 A ₂ = 0 A ₄ = -5.7279 × 10 ^-4 A ₆ = 5.4469 × 10 ^-6 A ₈ = -3.8768 × 10 ^-7 A ₁₀ = 0 16th surface K = 0 A ₂ = 0 A ₄ =- 4.2891 x 10 ^-5 A ₆ = 9.1978 x 10 ^-5 A ₈ = -1.0 100 x 10 ^-5 A ₁₀ = 0 18th surface K = 0 A ₂ = 0 A ₄ = -1.1036 x 10 ^-3 A ₆ = 2.0641 x 10 ^-5 A ₈ = 9.2983 x 10 ^-6 A ₁₀ = 0

When the zoom data D0 (distance from the object to the first surface) is ∞, wide-angle end middle telephoto end f (mm) 4.00153 6.92963 12.00205 Fno. 2.6604 3.4644 5.0148 D0 ∞ ∞ ∞ ∞ D6 1.10093 3.68362 1.10192 D9 10.12509 4.25142 0.60401 D15 3.24220 6.53134 12.76221 D17 0.70000 0.70000 0.70000 D20 1.00000 1.00000 1.00000 D0 (distance from object to first surface) is short distance (20c
m) Wide-angle end Mid-telephoto end D0 200.0000 200.0000 200.0000 D6 1.10093 3.68362 1.10192 D9 10.12509 4.25142 0.60401 D15 3.07343 6.04460 11.44083 D17 0.86877 1.18674 2.02138 D20 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.

[0116]

[0117]

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 vertical direction is advantageous for downsizing because it requires less space for bending, but if it is possible to bend in the long side direction, it is possible to bend the long side or the short side. It is also preferable because it can be bent to the side and the degree of freedom in camera design incorporating the lens is increased. In each of the above embodiments, the low pass filter is not incorporated, but a low pass filter may be inserted. In each embodiment, the horizontal pixel pitch a of the electronic image sensor is
Any of the following tables may be used.

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. 55 is a diagram showing an example of a pixel array of an electronic image pickup element 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. 58) 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 provided on the surface of the CCD cover glass CG on the incident surface side or on another lens. 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 that reduces 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. 58, 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. 58, 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. 59 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 embodiments, 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. 60 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 at the air distance 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. 61, 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. 61 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.

As the light quantity adjusting means, as shown in FIG. 63, a filter surface capable of adjusting the light quantity may be provided so as to suppress unevenness of the light quantity. The filter surface in FIG. 63 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, considering the 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. 64, 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 matched,
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. 65 is a schematic configuration 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. 66A is a rear view, FIG. 66B is a front view, and FIGS. 66A to 66D are views of the rotary shutter curtain B rotating from the image side. In FIG. 65, A is a shutter substrate, B is a rotary shutter curtain, C is a rotary axis of the rotary shutter curtain, and D is
1 and D2 are gears.

In the electronic image pickup device of the present invention, the shutter substrate A is arranged immediately before the image plane or in any 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 of FIGS. 66 (a) to 66 (d) over time. 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 embodiment of the present invention described above, these shutters and variable transmittance filters are arranged, for example, on the 16th surface of the second to eighth 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. In the embodiment of the present invention,
By adjusting the shape of the transmission region of the variable transmittance filter, a flare stop is provided.

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.

67 to 69 are conceptual views of a configuration 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. 67 is a digital camera 40.
6 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. The digital camera shown in FIG. 69 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, etc. When the shutter 45 arranged at 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 this. 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. 69, a plane parallel plate is arranged as the cover member 50, but a lens having power may be used.

Next, FIGS. 70 to 72 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. Fig. 70 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. 72 is a side view of FIG.

As shown in FIGS. 70 to 72, 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, 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 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. 70 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.

FIG. 73 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. 73 (a) is a front view of the mobile phone 400, FIG. 73 (b) is a side view, and FIG. 73 (c) is a cross-sectional view of the photographing optical system 405. As shown in FIGS. 73 (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 onto the image pickup element chip 162 so that the image pickup unit 1 is
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 the 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 same have the following features in addition to the invention described in the claims.

(1) The most object side lens group is composed of, in order from the object side, a negative lens component, a reflective optical element having a reflecting surface for bending the optical path, and a positive lens component, and the following conditional expression is satisfied. The zoom lens according to any one of claims 1 to 6, wherein. 1.0 <-f11 / √ (fw · fT) <2.5 1.4 <f12 / √ (fw · fT) <3.2 where f11 is the focal length of the negative lens component in the most object side lens group. , F12 in the lens group closest to the object side,
The focal length of the positive lens component, fw is the focal length of the entire system at the wide-angle end of the zoom lens, and fT is the focal length of the entire system at the telephoto end of the zoom lens.

(2) An electronic image pickup device having the zoom lens described in (1) above and an electronic image pickup device arranged on the image side thereof, and satisfying the following conditional expression. 0.7 <d / L <2.0, where d is the air-equivalent length measured along the optical axis from the image-side apex of the negative lens component to the object-side apex of the positive lens component in the most object-side lens unit, L is the diagonal length of the effective image pickup area of the electronic image pickup device.

(3) The electronic image pickup apparatus according to (2), wherein the reflective optical element is a prism and the following conditional expression is satisfied. 1.55 <npri where npri is the refractive index of the medium at the d-line of the reflective optical element.

(4) The zoom lens described in (1) above, characterized in that the negative lens component of the most object side lens unit is composed of a negative single lens, and the following condition is satisfied. 26 <ν1n−0.15 <√ (fw · fT) / f1 <0.
5 where ν1N is the Abbe's number on the d-line basis of the medium of the negative single lens of the lens group closest to the object, and f1 is the focal length of the lens group closest to the object.

(5) The first object lens group is composed of, in order from the object side, a negative single lens element, a reflective optical element, and a positive single lens element. Zoom lens.

(6) The first lens group has a positive refractive power, and the third lens group moves only to the object side during zooming,
The zoom lens according to claim 2, wherein the lens group closest to the image side includes an aspherical surface and is fixed during zooming.

(7) The zoom lens according to any one of claims 2 to 4, which satisfies the following conditional expression. 0.3 <−βRw <0.8 0.8 <fRw / √ (fw · fT) <1.8 where βRw is the composite magnification after the third lens group at the wide-angle end when focusing on an object point at infinity, fRw is a combined focal length after the third lens group at the wide-angle end when focusing on an object point at infinity, fRw
w is the focal length of the entire system at the wide-angle end of the zoom lens, f
T is the focal length of the entire system at the telephoto end of the zoom lens.

(8) The zoom lens according to claim 3, wherein the following conditional expression is satisfied: 0.16 <D12min / √ (fw · fT) <
0.26 where D12min is the minimum value in the possible range between the first lens group and the second lens group when focusing on an object point at infinity, f
w is the focal length of the entire system at the wide-angle end of the zoom lens, f
T is the focal length of the entire system at the telephoto end of the zoom lens.

(9) The zoom lens according to claim 4, wherein the following conditional expression is satisfied: 1.0 <| fF | / √ (fw · fT) <6.0 where fF is the focusing operation for a short-distance object point, which is arranged between the third lens group and the image-side lens group. At this time, the focal length of the lens group moving on the optical axis, fw is the focal length of the entire system at the wide-angle end of the zoom lens, and fT is the focal length of the entire system at the telephoto end of the zoom lens.

(10) The third lens group comprises two positive lenses and one negative lens, and the negative lens is cemented with at least one of the positive lenses. The zoom lens according to any one of to 4.

(11) The third lens group is composed of, in order from the object side, a positive single lens and a cemented lens component in which a positive lens and a negative lens are cemented.
The zoom lens described in 0).

(12) The third lens group is composed of, in order from the object side, a cemented lens component obtained by cementing a positive lens and a negative lens, and a positive single lens.
The zoom lens described in 0).

(13) The zoom lens described in (11) above, which satisfies the following conditional expression. 0.4 <R _C3 / R _C1 <0.85 where R _C3 is the radius of curvature on the optical axis of the most image-side surface of the cemented lens component in the third lens group, and R _C1 is the cemented lens in the third lens group. It is the radius of curvature of the surface of the lens component closest to the object on the optical axis.

(14) The zoom lens described in (12) above, which satisfies the following conditional expression. 0.8 < _RC3 / _RC1 <1.3 where _RC3 is the radius of curvature on the optical axis of the most image-side surface of the cemented lens component in the third lens group, and _RC1 is cemented in the third lens group. It is the radius of curvature of the surface of the lens component closest to the object on the optical axis.

(15) An electronic image pickup device including the zoom lens described in (11) or (13) above and an electronic image pickup device arranged on the image side thereof, and satisfying the following conditional expression: . _{-0.3 <L / R C2 <1.0} 15 <ν CP -ν CN where, L is the diagonal length of the image pickup device to be used (mm), R _C2
Is the radius of curvature of the cemented surface of the cemented lens component in the third lens group on the optical axis, ν _CP is the Abbe number of the medium of the positive lens of the cemented lens component in the third lens group, and ν _CN is the cemented lens in the third lens group It is the Abbe number of the medium of the negative lens of the component.

(16) An electronic image pickup device comprising the zoom lens described in (12) or (14) above and an electronic image pickup device arranged on the image side thereof, and satisfying the following conditional expression: . -0.1 <L / R _C2 <0.8 15 <ν _CP −ν _CN where L is the diagonal length (mm) of the image sensor used, R _C2
Is the radius of curvature of the cemented surface of the cemented lens component in the third lens group on the optical axis, ν _CP is the Abbe number of the medium of the positive lens of the cemented lens component in the third lens group, and ν _CN is the cemented lens in the third lens group It is the Abbe number of the medium of the negative lens of the component.

(17) The zoom lens according to (1) or (1), wherein the negative lens component of the most object-side lens unit has an aspherical surface.

(18) The zoom lens described in (17) above, which satisfies the following conditional expression. _{-2.0 <(R 1PF + R 1PR} ) / (R 1PF -R 1PR)
<1.0 However, R _1PF is the radius of curvature on the optical axis of the object side surface of the positive lens component in the most object side lens group, R _{1 PR} is on the optical axis of the image-side surface of the positive lens component in the most object side lens group Is the radius of curvature of.

(19) The zoom lens according to claim 2, wherein the second lens group is composed of two lenses, a negative lens and a positive lens, in order from the object side.

(20) The zoom according to the above (19), wherein the second lens group is a cemented lens component in which two lenses, a negative lens and a positive lens, are cemented in order from the object side. lens.

(21) The zoom lens described in (20) above, which satisfies the following conditional expression. -1.5 <(R _2F + R _2R ) / (R _2F -R _2R ) <
0.8 where R _2F is the radius of curvature on the optical axis of the object-side surface of the second lens group (the cemented lens component), and R _2R is the image-side surface of the second lens group (the cemented lens component). Is the radius of curvature on the optical axis of.

(22) The zoom lens satisfies the following conditional expression: (1) to (5), above (1),
The zoom lens according to any one of (4) to (14) and (17) to (21). 1.8 <fT / fw where fw is the focal length of the entire zoom lens system at the wide-angle end, and fT is the focal length of the entire zoom lens system at the telephoto end.

(23) Any of the above-mentioned (2), (3), (15), and (17) is characterized in that the total angle of view at the wide-angle end in the electronic image pickup device is 55 degrees or more. The electronic imaging device according to item 1.

(24) The wide angle end total angle of view in the electronic image pickup device is 80 degrees or less.
The electronic image pickup device according to 3).

(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 is satisfied. The electronic imaging device according to any one of (2), (3), (15), and (17). F ≧ a / (1 μm)

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

(27) The electronic image pickup device according to the above (26), wherein the intersection is located inside or within the apex of the lens.

(28) 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 image pickup device according to any one of (25) to (27), wherein the electronic image pickup device is arranged inside.

(29) 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 any one of (25) to (28).

(30) The electronic image pickup device as described in any one of (25) to (29) above, 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.

(31) It is characterized in that each of the medium boundary surfaces arranged between the zoom lens and the image pickup surface is substantially a flat surface, and there is no spatial frequency conversion action like an optical low pass filter. Above (25) ~ (2
9. The electronic image sensor according to any one of 9).

[0185]

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 cross-sectional view taken along the optical axis showing the optical configuration of a zoom lens used in an electronic image pickup apparatus according to the fourth embodiment of 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. 20 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens according to Example 4 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. 21 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 4 upon focusing on an object point at infinity, showing the state at the wide-angle end.

FIG. 22 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens according to Example 4 upon focusing on an object point at infinity, and shows an intermediate state.

FIG. 23 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 4 upon focusing on an object point at infinity, showing the state at the telephoto end.

FIG. 24 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 4 upon focusing on a short-distance object point, showing the state at the wide-angle end.

FIG. 25 is a diagram showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 4 upon focusing on an object point at a short distance, and shows an intermediate state.

FIG. 26 is a diagram showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 4 upon focusing on a short-distance object point, showing the state at the telephoto end.

FIG. 27 is a sectional view taken along the optical axis showing the optical configuration of a fifth embodiment of the zoom lens used in the electronic image pickup device according to the present invention, showing the state at the time of bending when focusing on an object point at infinity at the wide-angle end. ing.

FIG. 28 is a cross-sectional view taken along the optical axis showing the optical configuration of the zoom lens of Example 5 when focused 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. 29 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 5 upon focusing on an object point at infinity, showing the state at the wide-angle end.

FIG. 30 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens according to Example 5 upon focusing on an object point at infinity, and shows an intermediate state.

FIG. 31 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 5 upon focusing on an object point at infinity, showing the state at the telephoto end.

FIG. 32 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 5 upon focusing on a short-distance object point, showing the state at the wide-angle end.

FIG. 33 is a diagram showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 5 upon focusing on an object point at a short distance, and shows an intermediate state.

FIG. 34 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 5 upon focusing on a short-distance object point, showing the state at the telephoto end.

FIG. 35 is a cross-sectional view taken along the optical axis showing the optical configuration of a zoom lens according to Example 6 used in the electronic image pickup apparatus according to the present invention, showing the state when bending when focusing on an object point at infinity at the wide-angle end. ing.

FIG. 36 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens of Example 6 when focused 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. 37 is a diagram showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens of Example 6 upon focusing on an object point at infinity, and shows the state at the wide-angle end.

FIG. 38 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification when the zoom lens of Example 6 is focused on an object point at infinity, and shows an intermediate state.

FIG. 39 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 6 upon focusing on an object point at infinity, showing the state at the telephoto end.

FIG. 40 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 6 upon focusing on a short-distance object point, showing the state at the wide-angle end.

FIG. 41 is a diagram showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens of Example 6 upon focusing on a short-distance object point, showing an intermediate state.

FIG. 42 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 6 upon focusing on a short-distance object point, showing the state at the telephoto end.

FIG. 43 is a sectional view taken along the optical axis showing the optical configuration of a zoom lens according to Example 7 used in the electronic image pickup apparatus according to the present invention, showing the state when bending when focusing on an object point at infinity at the wide-angle end. ing.

FIG. 44 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens of Example 7 when focused 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. 45 is a cross-sectional view taken along the optical axis showing the optical configuration of a zoom lens according to Example 8 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. 46 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens according to Example 8 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. 47 is a cross-sectional view taken along the optical axis, showing the optical configuration of a zoom lens according to Example 9 used in the electronic image pickup apparatus according to the present invention, showing the state at the time of bending when focusing on an object point at infinity at the wide-angle end. ing.

48 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens of Example 9 when focused on an object point at infinity, FIG.
(a) shows the state at the wide-angle end, (b) shows the intermediate state, and (c) shows the state at the telephoto end.

FIG. 49 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 9 when focused on an object point at infinity, and shows the state at the wide-angle end.

FIG. 50 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 9 when focused on an object point at infinity, and shows an intermediate state.

FIG. 51 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 9 when focused on an object point at infinity, showing the state at the telephoto end.

FIG. 52 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens according to Example 9 upon focusing on an object point at a short distance, and shows the state at the wide-angle end.

FIG. 53 is a diagram showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 9 upon focusing on an object point at a short distance, and show intermediate states.

FIG. 54 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 9 upon focusing on a short-distance object point, showing the state at the telephoto end.

FIG. 55 is an explanatory diagram showing an example of a pixel array of an electronic image pickup element used in each example of the present invention.

FIG. 56 is a graph showing transmittance characteristics of an example of a near infrared sharp cut coat.

FIG. 57 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. 58 is a diagram showing a color filter arrangement of complementary color mosaic filters.

FIG. 59 is a graph showing an example of wavelength characteristics of a complementary color mosaic filter.

FIG. 60 is an explanatory diagram showing a modified example of the diaphragm S used in the electronic image pickup apparatus according to each embodiment of the present invention.

FIG. 61 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.

62 is a perspective view showing a specific example of a state in which the light amount adjusting means shown in FIG. 61 is applied to the present invention.

FIG. 63 is an explanatory diagram showing another example of the light amount adjusting means applicable to the electronic image pickup device according to each embodiment of the present invention.

FIG. 64 is an explanatory diagram showing still another example of the light amount adjusting means applicable to the electronic image pickup apparatus according to each embodiment of the present invention.

FIG. 65 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. Back view, (b)
Is a front view.

66 (a) to 66 (d) are views showing how the rotary shutter curtain B shown in FIG. 65 rotates, as seen from the image plane side.

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

68 is a rear perspective view of the digital camera 40 shown in FIG. 67. FIG.

69 is a cross-sectional view showing the configuration of the digital camera 40 shown in FIG. 67.

FIG. 70 is a personal computer 3 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.
It is a front perspective view which opened the cover of 00.

71 is a sectional view of the taking optical system 303 of the personal computer 300 shown in FIG. 70.

72 is a side view of FIG. 70. FIG.

FIG. 73 is a diagram showing a mobile phone which is an example of an information processing device in which the folding zoom lens of the present invention is incorporated as a photographing optical system, (a) is a front view of the mobile phone 400, and (b) is a view.
(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 gear CG CCD cover glass E observer eye G1 first lens group G2 second lens group (first moving lens group) G3 3 lens groups (2nd 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 L2 Biconvex positive lens L1 ₂ 'with convex surface facing the object side was directed a positive meniscus lens L2 ₁ biconcave negative lens L2 positive meniscus lens L3 ₁ 'convex biconvex positive lens L3 ₂ object side toward the positive meniscus lens L3 ₁ convex surface on the object side with its ₂ convex surface on the object side negative meniscus lens L3 ₂ 'positive meniscus lens L3 ₃ double convex having a convex surface directed toward the object side positive lens L3 _3' negative meniscus lens L4 ₁ object side with a convex surface on the object side Convex positive meniscus lens L4 ₁ "" object side with a concave surface facing the object side '"negative meniscus lens L4 ₁ with a concave surface facing the object side" biconcave negative lens L4 _1' negative meniscus lens L4 ₁ with a convex surface Positive meniscus lens L4 ₂ biconvex positive lens L4 ₂ ′ Positive meniscus lens L4 ₂ ″ with concave surface facing the object side Negative lens L5 ₁ having concave surface on the object side and flat surface on the image side L5 ₂ Biconvex positive lens L5 ₂ Biconcave negative lens R1 Reflective optical element S Aperture stop 1A, 1B, 1C, 1D Aperture 10 Turret 11 Rotation axis 40 Digital camera 41 Imaging optical system 42 Photographing optical path 43 Finder optical system 44 Finder 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-of-view 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 Photographic optical system 304 Photographic optical path 305 Image 400 Mobile phone 401 Microphone Part 402 Speaker part 403 Input dial 404 Monitor 405 Shooting optical system 406 Antenna 407 Shooting optical path

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H087 KA01 LA02 PA07 PA20 PB10                       QA02 QA06 QA17 QA21 QA26                       QA39 QA41 QA46 RA01 SA63                       SA64 SA65 SA72 SA76 SB03                       SB13 SB24 SB32 SB43 TA01                       TA03 TA08                 5C022 AB66 AC42 AC54 AC65 AC66                       AC69 AC74 AC78

Claims (6)

[Claims] 1. A most object side lens group which is located closest to the object side and is fixed on the optical axis both during zooming and during focusing operation, and an object side lens group which is located closest to the image side and is fixed along the optical axis at least during focusing operation. An image-side lens group that is, and at least a moving lens group that is located between the most object-side lens group and the most image-side lens group and that moves on the optical axis during zooming, The side lens group includes, in order from the object side, a negative lens component, a reflective optical element having a reflecting surface for bending an optical path, and a positive lens component, and the most image side lens group includes at least one aspherical surface. A zoom lens having. 2. A reflective optical element having a reflective surface for bending an optical path in order from the object side, a first lens group as a most object side lens group fixed at the time of zooming, and a negative refractive power. Then, as a second lens group as a first moving lens group that moves on the optical axis during zooming, and as a second moving lens group that has a positive refractive power and moves on the optical axis during zooming It has a third lens group and an image-side lens group arranged closest to the image side, and the second lens group produces an image when zooming from the wide-angle end to the telephoto end when focusing on an object point at infinity. A zoom lens that moves back and forth with a convex trajectory to the side. 3. The zoom lens according to claim 2, wherein the second lens unit is extended toward the object side when focusing on a short-distance object point. 4. A lens group, which moves on the optical axis when focusing on a short-distance object point, is arranged between the third lens group and the most image-side lens group. The zoom lens described in 2. 5. The third lens group is composed of a cemented lens component in which a positive lens and a negative lens are cemented and two lens components of a single lens, and when zooming from the wide-angle end to the telephoto end, It moves only to the object side, It is characterized by the above-mentioned.
The zoom lens according to any one of 4 above. 6. An electronic image pickup apparatus comprising the zoom lens according to claim 1 and an electronic image pickup element arranged on an image side thereof.