JP2003329932A - Zoom lens and electronic image pickup device having 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, realizing a camera made extremely thin in the depth direction, easily miniaturized because a driving mechanism is simple, and easily made small in proportion to the miniaturization of an imaging device in the future, and an electronic image pickup device using the zoom lens. <P>SOLUTION: The zoom lens is provided with at least a lens group G1 positioned nearest to an object side and fixed on an optical axis both at the time of varying power and at the time of focusing operation, a lens group G4 positioned nearest to an image side and fixed on the optical axis at least at the time of focusing operation, and 1st and 2nd moving lens groups G2 and G3 positioned between the lens groups G1 and G4 and moving on the optical axis at the time of varying power. The lens group G1 is constituted of a negative lens component L1<SB>1</SB>, a surface mirror 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 the lens group G4 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. In addition, there is a physical limitation in the thickness direction of the lens component, which is the processing limit size, and the length of the collapsible lens barrel is determined by the thickness of the lens component. However, it is not possible to expect a proportional reduction in the depth of the camera.

On the other hand, as shown in the retractable lens barrel, the start-up time for the camera to be used (lens protrusion time)
It is also waterproof and dustproof, and the optical path (optical axis) of the optical system is designed to make the camera extremely thin in the depth direction.
A configuration in which the mirror is bent by a reflective optical element such as a mirror is also conceivable. In this case, although the thickness in the depth direction can be reduced, the total length of the optical path after bending becomes long, and therefore dimensions other than the depth tend to be large. However, it can be expected that the configuration in which the optical path is bent can be made thinner in proportion to further miniaturization of the image pickup device in the future. However, on the other hand, it is necessary to consider the influence of diffraction due to the miniaturization of the image sensor.

The present invention has been made in view of such 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,
In addition, a zoom lens and an electronic image pickup having the zoom lens, which can be a camera having an extremely thin depth direction, a driving mechanism is simple and easily downsized, and can be easily reduced in proportion to downsizing of an image pickup device in the future The purpose is to provide a device.

[0007]

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;
It has at least a first moving lens group and a second moving lens group that move on the optical axis at the time of zooming, and the most object side lens group has, in order from the object side, a negative lens component and reflection for bending an optical path. It is characterized in that it comprises a surface mirror having a surface and a positive lens component, and the most image side lens group has at least one aspherical surface.

The zoom lens according to the second aspect of the present invention comprises, in order from the object side, a positive lens component, and has a first lens group as the most object side lens group which is fixed during zooming and has a negative refractive power. Then, a second lens group as a first moving lens group that moves on the optical axis at the time of zooming, and a third lens group as a second moving lens group having a positive refractive power and moving on the optical axis at the time of zooming. A surface mirror having a lens group and an image-side lens group arranged closest to the image side, wherein the first lens group has, in order from the object side, a negative lens component and a surface mirror having a reflecting surface for bending an optical path. The reflective surface has a variable shape.

The zoom lens according to the third aspect of the present invention is the zoom lens according to the first or second aspect of the present invention, wherein the second lens group is used when zooming from the wide-angle end to the telephoto end when focusing on an object point at infinity. Moves reciprocally on the optical axis in a convex locus toward the image side.

The zoom lens according to the fourth invention is characterized in that, in any one of the first to third inventions, the focusing operation is performed by changing the shape of the reflecting surface.

The zoom lens according to the fifth aspect of the present invention is the zoom lens according to any one of the first to fourth aspects of the present invention, wherein the reflecting surface is a thin film coated with a metal or a dielectric, and the thin film is A shape of the reflecting surface is connected to a power source through a plurality of electrodes and a variable resistor, and includes an arithmetic unit for controlling the variable resistance value of the variable resistor, and controlling the distribution of electrostatic force applied to the thin film. Is configured to be variable.

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.

[0013]

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 image pickup apparatus of the present invention employs a configuration in which the optical path (optical axis) of the zoom lens system is bent by a reflective optical element such as a mirror, and various devices are incorporated for downsizing.

The basic construction of the zoom lens system according to the present invention is such that the most object side lens group (hereinafter referred to as the first lens group) is a negative lens component in order from the object side, and a reflection for bending the optical path. It is composed of a surface (front surface mirror) and a positive lens component, and is immovable both during zooming and during focusing, and the lens group closest to the image side (hereinafter referred to as the final lens group). , Has an aspherical surface so as to be immovable at the time of focusing, and further has another lens group that is movable for zooming between the two groups. (In the present application, the lens component is a lens in which only the lens surface closest to the object side and the lens surface closest to the image are in contact with the air gap, and the air gap is not included between them.
One unit is a single lens or a cemented lens. ) However, a reflecting surface (surface mirror) for bending the optical path to the first lens group
The provision of two causes the following two problems. First, the entrance pupil becomes deeper, and each lens element that originally constitutes the first lens group having a large diameter is further enlarged, and the establishment itself of the optical path bending becomes a problem. Secondly, the composite system magnification of each lens group, which originally has a variable power function and is responsible for the variable power function on the image side of the first lens group, approaches zero, and the variable power becomes low relative to the amount of movement.

Therefore, first, the conditions for establishing the bending of the optical path will be described. When the reflecting surface (surface mirror) for bending the optical path is provided in the first lens group, the entrance pupil position tends to be inevitably deeper, and the diameter and size of each optical element forming the first lens group is enlarged. However, it becomes difficult to physically bend the optical path. Therefore, the first lens group,
The negative pupil having a convex surface directed to the object side, the reflecting surface (surface mirror) for bending the optical path, and the positive lens in order from the object side make the entrance pupil shallow.

As described above, in order to secure a space for bending the optical path, the negative lens and the positive lens of the first lens group have a strong power of a certain level or more and are arranged apart from each other. In addition, each off-axis aberration such as coma, astigmatism, and distortion is inevitably worsened, but this can be corrected by introducing an aspherical surface into the final lens group. On the other hand, the amount of off-axis aberration correction by the aspherical surface of the final lens group is quite large, and if rear focus is performed using this, the off-axis aberration changes significantly. Therefore,
It is preferable to use another optical element in the system such that the final lens group is immovable at the time of focusing and, for example, the surface shape of the reflecting surface (surface mirror) for bending the optical path is controlled to be variable.

In order to physically establish the above bending,
It is better to satisfy the following conditional expressions (1) and (2), and further to (3). 0.9 <-f11 / √ (fw · fT) <2.4 (1) 1.6 <f12 / √ (fw · fT) <3.6 (2) 1.4 <d / L <3 .0 (3) where f11 is the focal length of the negative lens component in the lens group closest to the object, f12 is the focal length of the positive lens component in the lens group closest to the object, and fw is the focal length of the entire system at the wide-angle end of the zoom lens. The distance, fT is the focal length of the entire system at the telephoto end of the zoom lens, d is the air 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 lens unit closest to the object. The converted length, L, is the diagonal length of the effective image pickup area of the electronic image pickup device.

In order to make the entrance pupil shallow and to physically bend the optical path, it is necessary to satisfy the conditional expressions (1) and (2) to increase the power of the lens elements on both sides of the first lens group. Good. If both conditional expressions (1) and (2) exceed the upper limit values, the entrance pupil remains deep, and therefore the diameter and size of each optical element that makes up the first lens group increases when trying to secure a certain angle of view. It becomes difficult to physically bend the optical path. On the other hand, if the lower limit of conditional expressions (1) and (2) is exceeded,
The diameter of the positive lens in the first lens group becomes large, which makes it difficult to correct off-axis aberrations such as coma, astigmatism, and distortion.

Conditional expression (3) is a conditional expression that regulates the length measured along the optical axis required to provide the reflecting surface (surface mirror) for bending the optical path. The value of conditional expression (3) is preferably as small as possible, but below the lower limit, the optical path bending is not established, or the light flux contributing to the image formation in the peripheral portion of the screen does not reach the image plane satisfactorily. On the other hand, conditional expression (3)
If the upper limit of is exceeded, it becomes difficult to correct each off-axis aberration as in conditional expressions (1) and (2).

It is more preferable to satisfy at least one of the following conditional expressions (1 '), (2') and (3 '). 1.1 <-f11 / √ (fw · fT) <2.1 ... (1 ′) 1.8 <f12 / √ (fw · fT) <3.3… (2 ′) 1.5 <d / L <2.7 (3 ') Further, it is best to satisfy at least one of the following conditional expressions (1 "), (2"), and (3 "): 1.3 <-f11 / √ ( fw · fT) <1.8 ... (1 ”) 2.0 <f12 / √ (fw · fT) <3.0… (2”) 1.6 <d / L <2.5… (3 ”)

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 each having a strong power of a certain level or more, the variation amount of the chromatic aberration of magnification due to the magnification change is large. It tends to be. Therefore, the following conditional expressions (4) and (5) should also be satisfied. 26 <ν1N (4) −0.1 <√ (fw · fT) / f1 <0.6 (5) where ν1N is the Abbe number of the object-side negative lens medium of the first lens group, and f1 is the first The focal length of one lens group, 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.

When the value goes below the lower limit of the conditional expression (4), the chromatic aberration of magnification varies greatly during zooming, which is not preferable. There is no limitation on the upper limit of conditional expression (4). Conditional expression
When the value exceeds the upper limit of (5), 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 (4) is satisfied. On the other hand, when the value goes below the lower limit of the conditional expression (5), the aberration variation due to the movement of the lens group that moves for zooming may increase.

It is even better if either of the following conditional expressions (4 ') and (5') is satisfied. 30 <ν1N (4 ')-0.05 <√ (fw · fT) / f1 <0.4 (5') Further, either of the following conditional expressions (4 ") and (5") is satisfied. And the best. 33 <ν1N ... (4 ") 0 <√ (fw · fT) / f1 <0.2 ... (5")

Next, a method of zooming and focusing a zoom lens having a reflecting surface (surface mirror) for bending the optical path will be described. The following three methods are conceivable as the scaling method. Reflecting surface (surface mirror) with negative refractive power in order from the object side
And a second lens group that has a positive refractive power and has a positive refractive power and that moves only to the object side during zooming from the wide-angle end to the telephoto end, and that is different from the second lens group during zooming. A zoom method that includes a third lens group that moves and a final lens group that has an aspherical surface and does not move. Reflecting surface (surface mirror) with positive refractive power in order from the object side
A first lens unit that is immovable and includes, a second lens unit that has negative refractive power and moves only to the image side during zooming from the wide-angle end to the telephoto end, and in the opposite direction to the second lens unit during zooming. A zoom system consisting of a third lens group that moves only and a final lens group. Reflecting surface (surface mirror) with positive refractive power in order from the object side
And a second lens group having a negative refracting power and having a positive refracting power and a reciprocating movement convex to the image side during zooming from the wide-angle end to the telephoto end, and a wide-angle end having a positive refracting power. A zoom system consisting of a third lens group that moves only to the object side when zooming from the zoom lens to the telephoto end, and a final lens group that has an aspheric surface and is immovable.

First, the above-mentioned method has a drawback that it is difficult to apply power to the third lens group in order to secure a zoom ratio, and the amount of movement tends to be too large and the inclination of the cam tends to become large. Therefore, in the present invention, the above method or method is adopted. 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. There are difficulties in correcting various off-axis aberrations, correcting lateral chromatic aberration, and the like. On the other hand, in the above method, there is no problem in aberration correction, zoom movement, and size, except when it is necessary to secure a space for moving the second lens group for focusing. Therefore, in the present invention,
The above method was adopted. Thereby, the focus can be eliminated by controlling the surface shape of the reflecting surface (surface mirror) for bending the optical path to be variable.

Furthermore, it is preferable that the following conditional expressions (6) and (7) are satisfied. 0.3 <-βRw <0.8 (6) 0.8 <fRw / √ (fw · fT) <2.0 (7) 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 (6), 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,
It is theoretically rare that the upper limit of conditional expression (6) is exceeded, but it still requires a lot of moving space. Conditional expression (7)
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 (6 ') and (7') is satisfied. 0.35 <−βRw <0.75 (6 ′) 1.0 <fRw / √ (fw · fT) <1.8 (7 ′) Furthermore, the following conditional expressions (6 ″) and (7 ″) ) It is the best to meet either. 0.4 <-βRw <0.7 (6 ") 1.2 <fRw / √ (fw · fT) <1.6 (7")

Focusing in the zoom lens of the present invention may be performed by moving any lens group in the normal zoom lens, but the amount of drive of the lens group in the zoom lens barrel is reduced to reduce the size. For this reason, it is preferable to variably control the shape of the reflecting surface of the first lens group to perform focusing. For example, the reflecting surface is composed of a thin film coated with a metal or a dielectric, the thin film is connected to a power source through a plurality of electrodes or a variable resistor, and further, an arithmetic unit for controlling a variable resistance value is provided, It is preferable to make the shape of the reflecting surface variable by controlling the distribution of the electrostatic force applied to the thin film.

By the way, it is advantageous that the reflecting surface having a variable shape is small in size in terms of manufacturability and controllability. In addition, the reduction of the camera depth when the downsizing of the image sensor progresses
The method of bending the optical path as in the present invention is more advantageous than the retractable method. Therefore, in order to make the camera even thinner, the following conditional expression (5) F ≧ a (5) is set for the horizontal pixel pitch a (μm) of the electronic image sensor with respect to the open F value at the wide-angle end of the zoom lens. 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 until the conditional expression (5) is satisfied, 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.

Further, 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 (5) (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.

Next, a method for satisfactorily ensuring the zoom ratio 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. A single lens and a cemented lens component of a positive lens and a negative lens in order from the object side. The cemented lens component of the positive lens and the negative lens, the single lens C.I. In order from the object side, there are three types of cemented lens components of a positive lens, a negative lens, and a positive lens.

Further, in order to keep the moving space of the second lens group and the third lens group that move 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, when the third lens group is constructed as in B or C above, on the contrary, the length becomes longer than in the case of A as described above, but at the exit pupil position or zooming. Since it is advantageous in terms of the change in F value, the smaller image sensor is suitable.

When the third lens group is constructed as in the above A, the following conditional expression (8A) is satisfied, and when the third lens group is constructed as in the above B, the following conditional expression is satisfied. It is good to satisfy (8B). 0.4 < _RC3 / _RC1 <0.8 (8A) 1.0 < _RC3 / _RC1 <10 (8B) where _RC3 is the most image side of the cemented lens component in the third lens group. The radius of curvature of the surface on the optical axis, R _C1, is the radius of curvature of the surface of the cemented lens component in the third lens group closest to the object side on the optical axis.

If the upper limits of conditional expressions (8A) and (8B) are exceeded, it is advantageous in correcting spherical aberration, coma aberration, and astigmatism of all system aberrations, but the effect of mitigating eccentricity sensitivity by cementing is effective. Less is.
On the other hand, if the lower limit values of conditional expressions (8A) and (8B) 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 A above, the following conditional expression (8'A) is satisfied, and the third lens group is
In the case of such a constitution, it is more preferable to satisfy the following conditional expression (8'B). _{0.45 <R C3 / R C1 <} 0.7 ... (8'A) 1.5 <R C3 / R C1 <8 ... (8'B) In addition, the third lens unit is constructed as described above A In this case, the following conditional expression (8 "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 (8 "B): 0.5 < _RC3 / _RC1 <0.6 (8" A) 2 < _RC3 / _RC1 < 6 ... (8 "B)

Further, regarding the chromatic aberration correction, the following conditional expression
(9A), (10A) (above, construct the third lens group as shown in A above.
Condition) or conditional expressions (9B), (10B) (above, the first
When the three lens groups are configured as in B) above,
good.       -0.7 <L / R_C2  <0.1… (9A)       15 <ν_CP  −ν_CN                              … (10A)       -1.1 <L / R_C2  <0… (9B)       15 <ν_CP  −ν_CN                              … (10B) 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 limit values of conditional expressions (9A) and (9B) are exceeded, it is advantageous for correction of axial chromatic aberration and lateral chromatic aberration, but chromatic aberration of spherical aberration is likely to occur, and in particular spherical aberration at the reference wavelength. However, spherical aberration of short wavelength causes an overcorrection condition, which causes color bleeding in an image, which is not preferable. 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. Conditional expression
Below the lower limits of (10A) and (10B), 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 (9'A) and (10'A) is satisfied, or the third lens group is When B is configured as in B above, the following conditional expressions (9'B), (10'B)
It is even better to satisfy at least one of the above. -0.6 <L / R _C2 <0.0 (9'A) 20 <ν _CP -ν _CN (10'A) -0.9 <L / R _C2 <-0.2 (9 ' B) 20 <ν _CP −ν _CN … (10'B)

Further, the third lens group is constructed as shown in A above.
If you want to make it, the lesser of the following conditional expressions (9 "A) and (10" A)
Either one is satisfied, or the third lens group
In the case of constructing like B, the following conditional expressions (9 "B), (10"
It is best to satisfy at least one of B).       -0.5 <L / R_C2  <-0.1… (9 "A)       25 <ν_CP  −ν_CN                              … (10 "A)       -0.7 <L / R_C2  <-0.3 ... (9 "B)       25 <ν_CP  −ν_CN                              … (10 "B) Also, conditional expressions (10A), (10'A), (10 "A), (10B), (10'B),
For (10 "B), ν _VCP−ν_VCNDoes not exceed 90
May be set to. Combinations of media with an upper limit of 90
It does not exist in nature. Furthermore, ν_VCP−ν_VCNIs 60
It is desirable not to exceed. Exceeds the upper limit of 60
Then, the material used becomes expensive.

On the other hand, when the third lens group is constructed as described above in C, it is preferable to satisfy at least one of the following conditional expressions (11) to (15). -4.0 <(R _CF + R _CR ) / (R _CF −R _CR ) <0 (11) where R _CF is the radius of curvature of the most object-side surface of the triplet cemented lens component on the optical axis, R _CR is the radius of curvature on the optical axis of the most image-side surface of the triplet cemented lens component. 0.6 <D
c / fw <1.8 (12) However, Dc is the distance on the optical axis from the most object side surface to the most image side surface of the triplet cemented lens component, and fw is at the wide-angle end of the zoom lens. This is the focal length of the entire system. 0.002 / mm ² <Σ | (1 / Rci) − (1 / Rca) | ² <0.05 / mm ² (13) where Rci is the i-th cemented lens element from the object side The radius of curvature of the surface on the optical axis, Rca is Rca = m /
| Σ (1 / Rci) | (i = 1 ... m), where
m is the number of joint surfaces, 2. 5 × 10 ⁻⁵ <Σ | (1 / νcj + 1) − (1 / νcj) | ² <4 × 10 ⁻³ (14) where νcj is the i-th d from the object side of the triplet cemented lens component. The Abbe number of the medium on a line basis is j = 1 ... N-1, where n is the number of lenses to be cemented. 0.005 <Σ | ncj + 1-ncj | ² <0.5 where ncj is the refractive index of the medium based on the i-th d-line from the object side of the triplet cemented lens component, j = 1 ... n-1 And
Here, n is 3, which is the number of lenses to be cemented.

Conditional expression (11) is a conditional expression that defines the shape factor of the cemented lens component having m (m ≧ 2) cemented surfaces among the lens groups that move during zooming. When the value goes below the lower limit of conditional expression (11), it becomes difficult to secure a variable power ratio or to shorten the total length in use (this is related to the volume at the time of collapse). On the other hand, when the value exceeds the upper limit of conditional expression (11), it becomes difficult to correct spherical aberration and coma even if an aspherical surface is introduced.

Conditional expression (12) is defined as the most object-side surface and the most image-side surface of the cemented lens component having m (m ≧ 2) cemented surfaces among the lens groups that move during zooming. Is a conditional expression that defines the distance (thickness) on the optical axis of. If the upper limit of conditional expression (12) is exceeded, the thickness of the entire system will not become thin when retracted. On the other hand, when the value goes below the lower limit of conditional expression (12), the radius of curvature of each cemented surface cannot be made small, and the effect of cementing (correction of chromatic aberration etc.) cannot be exhibited.

Conditional expression (13) is a conditional expression for each cemented surface to exert the aberration correction effect. If the upper limit of conditional expression (13) is exceeded, it is advantageous for aberration correction, but the upper limit of conditional expression (12) tends to be exceeded. On the other hand, when the value goes below the lower limit of conditional expression (13), it is advantageous to make the lens system thin, but it is not preferable because the aberration correction effects are canceled by each other.

Conditional expression (14) is a conditional expression which defines the chromatic aberration correction of the cemented lens component having m (m ≧ 2) cemented surfaces among the lens groups that move during zooming. When the value goes below the lower limit of conditional expression (14), chromatic aberration correction is insufficient. On the other hand, if the upper limit of conditional expression (14) is exceeded, chromatic aberration correction may become excessive.

Conditional expression (15) defines the spherical aberration, coma aberration, and field curvature correction of the cemented lens component having m (m ≧ 2) cemented surfaces in the lens group that moves during zooming. It is a conditional expression. When the value goes below the lower limit of conditional expression (15), spherical aberration and coma aberration are insufficiently corrected, and Petzval sum tends to have a large negative value. On the other hand, if the upper limit of conditional expression (15) is exceeded, higher-order components of spherical aberration and coma are likely to occur, and the Petzval sum tends to have a large positive value. The conditional expressions (14) and (15) are conditional expressions that prescribe the case where the positive lens has a lower refractive index and a higher Abbe number than the negative lens.

For each of conditional expressions (11) to (15),
Further, if the conditional expressions (11 ′) to (15 ′) are satisfied, it is possible to achieve thinner and higher performance. _{-3.0 <(R CF + R CR} ) / (R CF -R CR) <-0.3 ... (11 ') 0.8 <Dc / fw <1.6 ... (12') 0.004 / mm ² <Σ | (1 / Rci) − (1 / Rca) | ² <0.04 / mm ² (13 ′) 1 × 10 ⁻⁴ <Σ | (1 / νcj + 1) − (1 / νcj) │ ² <3 × 10 ^-3 (14 ') 0.01 <Σ│ncj + 1-ncj│ ² <0.4 (15')

If each of the conditional expressions (11) to (15) is further limited to the following conditional expressions (11 ") to (15"), the thinnest and highest performance can be achieved. _{-2.0 <(R CF + R CR} ) / (R CF -R CR) <-0.5 ... (11 ") 1.0 <Dc / fw <1.4 ... (12") 0.006 / mm ² <Σ | (1 / Rci) − (1 / Rca) | ² <0.03 / mm ² (13 ″) 2 × 10 ⁻⁴ <Σ | (1 / νcj + 1) − (1 / νcj) │ ² <2 × 10 ^-3 (14 ") 0.02 <Σ│ncj + 1-ncj│ ² <0.3 (15")

Further, in the zoom lens of 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 (16). _{-2.5 <(R 1PF + R 1PR} ) / (R 1PF -R 1PR) <0.6 ... (16) 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 (16) 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 (16), the entrance pupil tends to be deep. The following conditional expression
It is even better to satisfy (16 '). _{-2 <(R 1PF + R 1PR} ) / (R 1PF -R 1PR) <0.2 ... (16 ') In addition, the following conditional expression (16 ") meet the best of. -1.5 <(R _{1PF + R 1PR) / (R 1PF} -R 1PR) <-0.2 ... (16 ")

Since the second lens group has a long focal length, it is sufficient to have two lenses, that is, a negative lens and a positive lens in order from the object side. Furthermore, joining is preferable because the sensitivity to eccentricity can be reduced. The cemented lens component preferably satisfies the following conditional expression (17). −1.6 <(R _2F + R _2R ) / (R _2F −R _2R ) <0.3 (17) where R _2F is the optical axis of the surface of the second lens group (the cemented lens component) closest to the object side. 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 (17) is exceeded, the entrance pupil tends to become deep. On the other hand, when the value goes below the lower limit of conditional expression (17), various off-axis aberrations are likely to occur. The following conditional expression
It is even better to satisfy (17 '). −1.2 <(R _2F + R _2R ) / (R _2F −R _2R ) <0.1 (17 ′) Further, it is best if the following conditional expression (17 ″) is satisfied: −0.8 <( R _2F + R _2R ) / (R _2F -R _2R ) <-0.1 ... (17 ")

The zoom lens used in the present invention preferably satisfies the following conditional expression (18). 1.8 <fT / fw (18) 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 (18), 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 thinning the infrared cut filter 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 (19) and (20). τ600 / τ550 ≧ 0.8 (19) τ700 / τ550 ≦ 0.08 (20) 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 (19 ') and (20')
It is even better to meet. τ600 / τ550 ≧ 0.85 (19 ′) τ700 / τ550 ≦ 0.05 (20 ′) Further, it is best to satisfy the following conditional expressions (19 ″) and (20 ″). τ600 / τ550 ≧ 0.9… (19 ") τ700 / τ550 ≦ 0.03… (20")

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 (21) and (22). τ400 / τ550 ≦ 0.08 (21) τ440 / τ550 ≧ 0.4 (22) It is more preferable to satisfy the following conditional expressions (21 ′) and (22 ′). τ400 / τ550 ≤ 0.06 (21 ') τ440 / τ550 ≥ 0.5 (22') 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 also 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.

[0064]

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.

As shown in FIG. 1, the electronic image pickup apparatus of the first embodiment has a zoom lens and a CCD which is an electronic image pickup element in order from the object side. In FIG. 1, I is the image pickup surface of the CCD. A flat plate-shaped CCD cover glass CG is provided between the zoom lens and the imaging surface I. The zoom lens includes, in order from the object side, a first lens group G1 and
It has a second lens group G2 that is a first moving lens group, an aperture stop S, a third lens group G3 that is a second moving lens group, and a fourth lens group G4. The first lens group G1 includes
In order from the object side, 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 biconvex positive lens L1 ₂ are included. The reflective optical element R1 is configured as a surface mirror that bends the optical path by 90 °. Further, the reflecting surface of the surface mirror is configured to be variable in shape, and the focusing operation is performed by changing the shape of the reflecting surface. The aspect ratio of the effective image pickup area in each embodiment of the present invention is 3: 4, and the bending direction is the horizontal direction. Second lens group G2
Is composed of, in order from the object side, a cemented lens of a 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. Third
The lens group G3 includes, in order from the object side, a biconvex positive lens L3 ₁
And a cemented lens of a biconcave negative lens L3 _2, and a positive meniscus lens L3 ₃ with a convex surface facing the object side, and has a positive refractive power as a whole. Fourth lens group G4
Is composed of a positive meniscus lens L4 ₁ having a concave surface facing the object side in order from the object side.

When zooming from the wide-angle end to the telephoto end, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 reciprocates in a convex locus toward the image side. (That is, after moving to the image side to temporarily widen the distance to the first lens group G1 and then moving to the object side to reduce the distance to the first lens group G1), the third lens group G3 is used as an aperture stop. It moves only to the object side together with S. Also,
The positions of the first lens group G1 and the fourth lens group G4 are fixed even during the focusing operation. The aspherical surface is the first lens group G1.
The image-side surface of the negative meniscus lens L1 ₁ with the convex surface facing the object side, the both surfaces of the positive meniscus lens L3 ₃ with the convex surface facing the object side in the third lens group G3, and the fourth lens group G4 are configured. Positive meniscus lens L4 with concave surface facing the object side
It is provided on the image side of ₁ .

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. Further, the third and fourth surfaces in the numerical data are virtual surfaces. As a reflection optical element having a reflection surface for bending the optical path, a prism having a refractive index of 1 is assumed, and the entrance surface and the exit surface thereof are assumed, and the air gap is actually set.

Numerical data 1 r ₁ = 61.5439 d ₁ = 0.7000 n _d1 = 1.80610 ν _d1 = 40.92 r ₂ = 6.2081 (aspherical surface) d ₂ = 1.7000 r ₃ = ∞ d ₃ = 6.8000 r ₄ = ∞ d ₄ = 0.1500 _{r 5 = 12.7178 d 5 = 1.5500} n d5 = 1.72916 ν d5 = 54.68 r 6 = -72.0943 d 6 = D6 r 7 = -9.2239 d 7 = 0.7000 n d7 = 1.69680 ν d7 = 55.53 r 8 = 6.5000 d 8 = 1.3500 n _d8 = 1.84666 ν _d8 = 23.78 r ₉ = 18.7314 d ₉ = D 9 r ₁₀ = ∞ (aperture) d ₁₀ = 0 r ₁₁ = 4.7900 d ₁₁ = 3.0000 n _{d 11} = 1.74320 ν _{d 11} = 49.34 r ₁₂ = -8.0000 d ₁₂ = 0.7000 n _d12 = 1.84666 v _d12 = 23.78 r ₁₃ = 11.8703 d ₁₃ = 0.3000 r ₁₄ = 8.3986 (aspherical surface) d ₁₄ = 1.0000 n _d14 = 1.69350 ν _d14 = 53.21 r ₁₅ = 19.5740 (aspherical surface) d ₁₅ = D15 r ₁₆ = ∞ (variable transmittance means or shutter _{position) d 16 = 4.4000 r 17 =} -6.4029 d 17 = 1.0000 n d17 = 1.58313 ν d17 = 59.38 r 18 = -5.3597 _{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 21 = ∞ ( imaging plane) d ₂₁ = 0

Aspheric coefficient 2nd surface K = 0 A ₂ = 0 A ₄ = -6.3011 × 10 ^-4 A ₆ = 6.3666 × 10 ^-6 A ₈ = -6.2546 × 10 ^-7 A ₁₀ = 0 14th surface K = 0 A ₂ = 0 A ₄ = 2.9509 × 10 ⁻⁴ A ₆ = 5.8599 × 10 ⁻⁵ A ₈ = 3.9534 × 10 ⁻⁶ A ₁₀ = 0 15th surface K = 0 A ₂ = 0 A ₄ = 4.1434 × 10 ^-3 A ₆ = 1.3121 × 10 ^-4 A ₈ ＝ 4.6939 × 10 ^-5 A ₁₀ = 0 18th surface K = 0 A ₂ = 0 A ₄ ＝ 1.8250 × 10 ^-3 A ₆ ＝ 1.0823 × 10 ^-4 A ₈ ＝ -2.0337 × 10 ^-5 A ₁₀ = 0

Zoom data When D0 (distance from object to first surface) is ∞               Wide-angle end Mid-telephoto end f (mm) 3.24880 5.63959 9.74406 Fno. 2.7241 3.4516 4.8572 D0 ∞ ∞ ∞ D6 0.89800 3.28004 0.90004 D9 9.70505 4.27059 0.89565 D15 1.70893 4.75924 10.51630 D20 1.00000 1.00000 1.00000

Second Embodiment FIG. 6 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 second embodiment of the present invention. The state at the time of bending is shown. FIG. 7 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens according to Example 2 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. 6, the electronic image pickup apparatus according to 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. 6, 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 that is a first moving lens group, an aperture stop S, a third lens group G3 that is a second moving lens group, and a fourth lens group G4. The first lens group G1 includes
In order from the object side, 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 biconvex positive lens L1 ₂ are included. The reflective optical element R1 is configured as a surface mirror that bends the optical path by 90 °. Further, the reflecting surface of the surface mirror is configured to be variable in shape, and the focusing operation is performed by changing the shape of the reflecting surface. The aspect ratio of the effective image pickup area in each embodiment of the present invention is 3: 4, and the bending direction is the horizontal direction. Second lens group G2
Is composed of, in order from the object side, a cemented lens of a 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. Third
The lens group G3 includes, in order from the object side, a biconvex positive lens L3 ₁
And a cemented lens of a biconcave negative lens L3 _2, and a positive meniscus lens L3 ₃ with a convex surface facing the object side, and has a positive refractive power as a whole. Fourth lens group G4
Is composed of, in order from the object side, a cemented lens of a biconcave negative lens L4 ₁ ′ and a biconvex positive lens L4 ₂ .

When zooming from the wide-angle end to the telephoto end, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 reciprocates in a convex locus toward the image side. (That is, after moving to the image side to temporarily widen the distance to the first lens group G1 and then moving to the object side to reduce the distance to the first lens group G1), the third lens group G3 is used as an aperture stop. It moves only to the object side together with S. Also,
The positions of the first lens group G1 and the fourth lens group G4 are fixed even during the focusing operation. The aspherical surface is the first lens group G1.
The image-side surface of the negative meniscus lens L1 ₁ having a convex surface facing the object side, the both surfaces of the positive meniscus lens L3 ₃ having a convex surface facing the object side in the third lens group G3, and both of the fourth lens group G4 It is provided on the image-side surface of the convex positive lens L4 ₂ .

Next, numerical data of optical members constituting the zoom lens of the second embodiment will be shown. Numerical data 2 r ₁ = 74.4969 d ₁ = 0.7000 n _d1 = 1.80610 ν _d1 ＝ 40.92 r ₂ = 6.3385 (aspherical surface) d ₂ = 1.7000 r ₃ = ∞ d ₃ = 6.8000 r ₄ = ∞ d ₄ = 0.1500 r ₅ = 12.2080 d ₅ = 1.5500 n _d5 = 1.72916 ν _d5 = 54.68 r ₆ = -169.5645 d ₆ = D ₆ r ₇ = -9.7882 d ₇ = 0.7000 n _d7 = 1.72916 ν _d7 = 54.68 r ₈ = 8.0000 d ₈ = 1.3500 n _d8 = 1.84666 ν _d8 = 23.78 r ₉ = 27.1517 d ₉ = D 9 r ₁₀ = ∞ (aperture) d ₁₀ = 0 r ₁₁ = 4.9532 d ₁₁ = 3.0000 n _{d 11} = 1.72916 ν _{d 11} = 54.68 r ₁₂ = -9.0000 d ₁₂ = 0.7000 n _d12 = 1.84666 ν _d12 ＝ 23.78 r ₁₃ ＝ 24.5762 d ₁₃ = 0.3000 r ₁₄ = 10.00773 (aspherical surface) d ₁₄ = 1.0000 n _d14 = 1.69350 ν _d14 ＝ 53.21 r ₁₅ = 12.2161 (aspherical surface) d ₁₅ ＝ D15 r ₁₆ ＝ ∞ (transmittance varying means or shutter arrangement position) d ₁₆ = 4.0000 r ₁₇ = -44.4371 d ₁₇ = 0.7000 n _d17 = 1.80518 ν _d17 = 25.42 r ₁₈ = 20.0000 d ₁₈ = 1.200 0 n _d18 = 1.58313 ν _d18 = 59.38 r ₁₉ = -10.5475 (aspherical surface) d ₁₉ = 0.7000 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 2nd surface K = 0 A ₂ = 0 A ₄ = -6.0504 × 10 ^-4 A ₆ = 4.3029 × 10 ^-6 A ₈ = -5.2183 × 10 ^-7 A ₁₀ = 0 14th surface K = 0 A ₂ = 0 A ₄ = 6.6247 × 10 ^-4 A ₆ = -2.9526 × 10 ^-5 A ₈ = 3.3686 × 10 ^-6 A ₁₀ = 0 15th surface K = 0 A ₂ = 0 A ₄ = 4.3514 × 10 ^-3 A ₆ = 2.7664 × 10 ^-5 A ₈ = 4.2826 × 10 ^-5 A ₁₀ = 0 19th surface K = 0 A ₂ = 0 A ₄ = 9.6272 × 10 ^-4 A ₆ ＝ 2.3883 × 10 ^-4 A ₈ = -3.0856 x 10 ^{-5 *} A ₁₀ = 0

When the zoom data D0 (distance from the object to the first surface) is ∞

Third Embodiment FIG. 8 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 third embodiment of the present invention, and 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. 9 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. 10 to 12 are diagrams showing spherical aberration, astigmatism, distortion, and lateral chromatic aberration of the zoom lens according to Example 3 upon focusing on an object point at infinity,
10 shows the state at the wide-angle end, FIG. 11 shows the state at the middle, and FIG. 12 shows the state at the telephoto end.

As shown in FIG. 8, the electronic image pickup apparatus of 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. 8, 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 that is a first moving lens group, an aperture stop S, a third lens group G3 that is a second moving lens group, and a fourth lens group G4. The first lens group G1 includes
In order from the object side, 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 biconvex positive lens L1 ₂ are included. The reflective optical element R1 is configured as a surface mirror that bends the optical path by 90 °. Further, the reflecting surface of the surface mirror is configured to be variable in shape, and the focusing operation is performed by changing the shape of the reflecting surface. The aspect ratio of the effective image pickup area in each embodiment of the present invention is 3: 4, and the bending direction is the horizontal direction. Second lens group G2
Is composed of, in order from the object side, a cemented lens of a 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. Third
The lens group G3 includes, in order from the object side, a biconvex positive lens L3 ₁
And a biconcave negative lens L3 ₂ and a positive meniscus lens L3 ₃ having a convex surface directed toward the object side, and has a positive refracting power as a whole. The fourth lens group G4 is composed of, in order from the object side, a cemented lens of a negative meniscus lens L4 ₁ ″ having a convex surface directed toward the object side and a biconvex positive lens L4 ₂ .

When zooming from the wide-angle end to the telephoto end, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 reciprocates in a convex locus toward the image side. (That is, after moving to the image side to widen the distance from the first lens group G1 and then moving toward the object side, the distance to the first lens group G1 is reduced). It moves only to the object side together with S. Also,
The positions of the first lens group G1 and the fourth lens group G4 are fixed even during the focusing operation. The aspherical surface is the first lens group G1.
The image-side surface of the negative meniscus lens L1 ₁ having a convex surface facing the object side, the object-side surface of the biconvex positive lens L3 ₁ in the third lens group G3, and the positive meniscus lens L3 having a convex surface facing the object side. The image-side surface of _{3 and} the image-side surface of the biconvex positive lens L4 ₂ in the fourth lens group G4.

Next, numerical data of optical members constituting the zoom lens of the third embodiment will be shown. Numerical data 3 r ₁ = 59.7815 d ₁ = 0.7000 n _d1 = 1.80610 ν _d1 ＝ 40.92 r ₂ = 6.0756 (aspherical surface) d ₂ = 1.7000 r ₃ = ∞ d ₃ = 6.8000 r ₄ = ∞ d ₄ = 0.1500 r ₅ = 11.7992 d ₅ = 1.5500 n _d5 = 1.72916 ν _d5 = 54.68 r ₆ = -179.5914 d ₆ = D ₆ r ₇ = -11.1399 d ₇ = 0.7000 n _d7 = 1.72916 ν _d7 = 54.68 r ₈ = 8.0000 d ₈ = 1.3500 n _d8 = 1.84666 ν _d8 = 23.78 r ₉ = 22.5506 d ₉ = D 9 r ₁₀ = ∞ (stop) d ₁₀ = 0 r ₁₁ = 4.4541 (aspherical surface) d ₁₁ = 2.6000 n _{d 11} = 1.74320 ν _{d 11} = 49.34 r ₁₂ = -36.5357 d ₁₂ = 0.7000 n _d12 = 1.84666 ν _d12 = 23.78 r ₁₃ = 5.8033 d ₁₃ = 1.0000 n _d13 = 1.69350 ν _d13 = 53.21 r ₁₄ = 20.1908 (aspherical surface) d ₁₄ = D14 r ₁₅ = ∞ (transmittance varying means or shutter) Arrangement position) d ₁₅ = 3.9000 r ₁₆ = 114.5613 d ₁₆ = 0.7000 n _d16 = 1.84666 ν _d16 = 23.78 r ₁₇ = 15.00000 d ₁₇ = 1.4000 n _d17 = 1.58313 ν _d17 = 59. 38 r ₁₈ = -13.0230 (aspherical surface) d ₁₈ = 0.7000 r ₁₉ = ∞ d ₁₉ = 0.6000 n _d19 = 1.51633 ν _d19 = 64.14 r ₂₀ = ∞ d ₂₀ = D 20 r ₂₁ = ∞ (imaging surface) d ₂₁ = 0

Aspherical coefficient second surface K = 0 A ₂ = 0 A ₄ = −5.886 61 × 10 ⁻⁴ A ₆ = 2.2837 × 10 ⁻⁶ A ₈ = −5.4903 × 10 ⁻⁷ A ₁₀ = 0 11th surface K = 0 A ₂ = 0 A ₄ = 7.8543 × 10 ^-5 A ₆ = 1.1512 × 10 ^-5 A ₈ = 1.2754 × 10 ^-6 A ₁₀ = 0 14th surface K = 0 A ₂ = 0 A ₄ = 4.7308 × 10 ^-3 A ₆ = 1.0524 × 10 ^-4 A ₈ = 7.9868 × 10 ^-5 A ₁₀ = 0 18th surface K = 0 A ₂ = 0 A ₄ = 5.4330 × 10 ^-4 A ₆ = 3.5735 × 10 ^-4 A ₈ ＝ -4.3307 × 10 ^-5 A ₁₀ = 0

Zoom data When D0 (distance from object to first surface) is ∞               Wide-angle end Mid-telephoto end f (mm) 3.25322 5.63788 9.74711 Fno. 2.6846 3.4315 4.8540 D0 ∞ ∞ ∞ D6 0.89897 3.36572 0.90042 D9 10.05921 4.38120 0.89765 D14 1.97939 5.18949 11.14311 D20 1.00000 1.00000 1.00000

Fourth Embodiment FIG. 13 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 fourth embodiment of the present invention. The state at the time of bending is shown. FIG. 14 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens according to the fourth 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. 15 to 17 are diagrams showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens according to Example 4 when focused on an object point at infinity. FIG. 15 is a wide angle end, and FIG. In the middle, FIG. 17 shows the state at the telephoto end.

As shown in FIG. 13, the electronic image pickup apparatus according to the fourth embodiment has, in order from the object side, a zoom lens and a CCD which is an electronic image pickup element. In FIG. 13, 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 a fourth lens group G4. First lens group G
Reference numeral 1 denotes, 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 the optical path, and a biconvex positive lens L1 ₂ . The reflective optical element R1 is configured as a surface mirror that bends the optical path by 90 °. Further, the reflecting surface of the surface mirror is configured to be variable in shape, and the focusing operation is performed by changing the shape of the reflecting surface. 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 biconvex positive lens L3 ₂ ′, and a biconcave negative lens L3.
3 ₃ is composed of a cemented lens of a ', and has a positive refractive power as a whole. The fourth lens group G4 includes a positive meniscus lens L4 ₁ ″ ′ having a convex surface directed toward the object side.

When zooming from the wide-angle end to the telephoto end, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 reciprocates in a convex locus toward the image side. (That is, after moving to the image side to widen the distance from the first lens group G1 and then moving toward the object side, the distance to the first lens group G1 is reduced). It moves only to the object side together with S. Also,
The positions of the first lens group G1 and the fourth lens group G4 are fixed even during the focusing operation. The aspherical surface is the first lens group G1.
To the image side surface of the negative meniscus lens L1 ₁ having a convex surface facing the inner object side, to the object side surface of the biconvex positive lens L3 ₁ in the third lens group G3, and to the object side forming the fourth lens group G4 It is provided on the object-side surface of the positive meniscus lens L4 ₁ ″ ′ with its convex surface facing.

Next, numerical data of optical members constituting the zoom lens of the fourth embodiment will be shown. Numerical data 4 r ₁ = 52.2760 d ₁ = 0.7000 n _d1 = 1.80610 ν _d1 ＝ 40.92 r ₂ = 5.7580 (aspherical surface) d ₂ = 1.7000 r ₃ = ∞ d ₃ = 6.8000 r ₄ = ∞ d ₄ = 0.1500 r ₅ = 16.0001 d ₅ = 1.5500 n _d5 = 1.72916 ν _d5 = 54.68 r ₆ = -30.1872 d ₆ = D6 r ₇ = -14.5275 d ₇ = 0.7000 n _d7 = 1.72916 ν _d7 = 54.68 r ₈ = 8.5000 d ₈ = 1.3500 n _d8 = 1.84666 ν _d8 = 23.78 r ₉ = 22.8461 d ₉ = D 9 r ₁₀ = ∞ (diaphragm) d ₁₀ = 0 r ₁₁ = 6.7921 (aspherical surface) d ₁₁ = 2.0000 n _{d 11} = 1.74320 ν _{d 11} = 49.34 r ₁₂ = -17.1573 d _{12 = 0.1500 r 13 = 6.6023 d} 13 = 2.0000 n d13 = 1.69680 ν d13 = 55.53 r 14 = -12.0000 d 14 = 0.7000 n d14 = 1.80518 ν d14 = 25.42 r 15 = 3.4303 d 15 = 2.5000 r 16 = ∞ ( transmission Rate varying means or shutter arrangement position) d ₁₆ = D16 r ₁₇ = 5.2486 (aspherical surface) d ₁₇ = 1.3000 n _d17 = 1.58313 ν _d17 = 59.38 r ₁₈ = 1.6752 d ₁₈ = 0.7000 r ₁₉ = ∞ d ₁₉ = 0.6000 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 = -7.5842 × 10 ^-4 A ₆ = 1.7230 × 10 ^-5 A ₈ = -1.0788 × 10 ^-6 A ₁₀ = 0 11th surface K = 0 A ₂ = 0 A ₄ = -6.3767 × 10 ^-4 A ₆ = -3.2039 × 10 ^-6 A ₈ = -1.8591 × 10 ^-7 A ₁₀ = 0 17th surface K = 0 A ₂ = 0 A ₄ = -9.5 208 x 10 ^-4 A ₆ = 1.7318 x 10 ^-4 A ₈ = -1.2845 x 10 ^-5 A ₁₀ = 0

Zoom data When D0 (distance from object to first surface) is ∞               Wide-angle end Mid-telephoto end f (mm) 3.24494 5.63626 9.75588 Fno. 2.5243 3.3051 4.8453 D0 ∞ ∞ ∞ D6 0.89968 3.58051 0.90275 D9 10.64759 4.65512 0.90377 D16 2.44627 5.75714 12.18681 D20 1.00000 1.00000 1.00000

Fifth Embodiment FIG. 18 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. 19 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.

As shown in FIG. 18, 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. 18, 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 a fourth lens group G4. First lens group G
Reference numeral 1 denotes, 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 the optical path, and a biconvex positive lens L1 ₂ . The reflective optical element R1 is configured as a surface mirror that bends the optical path by 90 °. Further, the reflecting surface of the surface mirror is configured to be variable in shape, and the focusing operation is performed by changing the shape of the reflecting surface. 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 biconvex positive lens L3 ₂ ′, and a biconcave negative lens L3.
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 having a concave surface facing the object side.

When zooming from the wide-angle end to the telephoto end, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 reciprocates in a convex locus toward the image side. (That is, after moving to the image side to widen the distance from the first lens group G1 and then moving toward the object side, the distance to the first lens group G1 is reduced). It moves only to the object side together with S. Also,
The positions of the first lens group G1 and the fourth lens group G4 are fixed even during the focusing operation. The aspherical surface is the first lens group G1.
To the image side surface of the negative meniscus lens L1 ₁ having a convex surface facing the inner object side, to the object side surface of the biconvex positive lens L3 ₁ in the third lens group G3, and to the object side forming the fourth lens group G4 and a surface of the positive meniscus lens L4 ₁ on the image side with a concave surface.

Next, numerical data of optical members constituting the zoom lens of the fifth embodiment will be shown. Numerical data 5 r ₁ = 102.2644 d ₁ = 0.7000 n _d1 = 1.80610 ν _d1 = 40.92 r ₂ = 6.4583 (aspherical surface) d ₂ = 1.7000 r ₃ = ∞ d ₃ = 6.8000 r ₄ = ∞ d ₄ = 0.1500 r ₅ = 11.8116 d ₅ = 1.6000 n _d5 = 1.72916 ν _d5 ＝ 54.68 r ₆ ＝ -211.6601 d ₆ ＝ D6 r ₇ ＝ -9.9617 d ₇ ＝ 0.7000 n _d7 ＝ 1.72916 ν _d7 ＝ 54.68 r ₈ ＝ 9.5000 d ₈ = 1.3000 n _d8 ＝ 1.84666 ν _d8 = 23.78 r ₉ = 41.0310 d ₉ = D 9 r ₁₀ = ∞ (aperture) d ₁₀ = 0 r ₁₁ = 7.0537 (aspherical surface) d ₁₁ = 1.7000 n _{d 11} = 1.74320 ν _{d 11} = 49.34 r ₁₂ = -15.1973 d ₁₂ = 0.1500 r ₁₃ = 4.7737 d ₁₃ = 2.1000 n _d13 = 1.74320 ν _d13 = 49.34 r ₁₄ = -17.0000 d ₁₄ = 0.7000 n _d14 = 1.84666 ν _d14 = 23.78 r ₁₅ = 2.5724 d ₁₅ = 1.7000 r ₁₆ = ∞ (transmission) rate changing means or shutter _{position) d 16 = D16 r 17 =} -34.4280 d 17 = 1.7000 n d17 = 1.57099 ν d17 = 50.80 r 18 = -5.8134 ( aspherical) d ₁₈ = 0.70 00 r ₁₉ = ∞ d ₁₉ = 0.6000 n _d19 = 1.51633 ν _d19 = 64.14 r ₂₀ = ∞ d ₂₀ = D 20 r ₂₁ = ∞ (imaging plane) d ₂₁ = 0

Aspheric coefficient 2nd surface K = 0 A ₂ = 0 A ₄ = -5.0036 × 10 ^-4 A ₆ = 3.1904 × 10 ^-6 A ₈ = -4.2907 × 10 ^-7 A ₁₀ = 0 11th surface K = 0 A ₂ = 0 A ₄ = -6.6405 × 10 ^-4 A ₆ = -7.9814 × 10 ^-7 A ₈ = -1.7621 × 10 ^-7 A ₁₀ = 0 18th surface K = 0 A ₂ = 0 A ₄ = 2.0836 x 10 ^-3 A ₆ = 8.7260 x 10 ^-5 A ₈ = -1.9733 x 10 ^-5 A ₁₀ = 0

Zoom data When D0 (distance from object to first surface) is ∞               Wide-angle end Mid-telephoto end f (mm) 3.25606 5.63818 9.75165 Fno. 2.7198 3.6329 5.3468 D0 ∞ ∞ ∞ D6 0.90008 3.07797 0.90116 D9 8.98407 3.96139 0.90291 D16 1.81805 4.66415 9.89808 D20 1.00000 1.00000 1.00000

Sixth Embodiment FIG. 20 is a sectional view taken along the optical axis showing the optical construction of a sixth embodiment of the zoom lens used in the electronic image pickup device 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. 21 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.

As shown in FIG. 20, 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. 20, 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 a fourth lens group G4. First lens group G
Reference numeral 1 denotes, 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 the optical path, and a biconvex positive lens L1 ₂ . The reflective optical element R1 is configured as a surface mirror that bends the optical path by 90 °. Further, the reflecting surface of the surface mirror is configured to be variable in shape, and the focusing operation is performed by changing the shape of the reflecting surface. 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 biconvex positive lens L3 ₂ ′, and a biconcave negative lens L3.
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 biconvex positive lens L4 ₁ ″ ″.

When zooming from the wide-angle end to the telephoto end, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 reciprocates in a convex locus toward the image side. (That is, after moving to the image side to temporarily widen the distance to the first lens group G1 and then moving to the object side to reduce the distance to the first lens group G1), the third lens group G3 is used as an aperture stop. It moves only to the object side together with S. Also,
The positions of the first lens group G1 and the fourth lens group G4 are fixed even during the focusing operation. The aspherical surface is the first lens group G1.
The object-side surface of the negative meniscus lens L1 ₁ having a convex surface directed toward the object side, and the biconvex positive lens L3 _{1 in} the third lens group G3.
Both surfaces of the biconvex positive lens L4 constituting the fourth lens group G4
It is provided on the image side of ₁ "".

Next, numerical data of optical members constituting the zoom lens of the sixth embodiment will be shown. Numerical data 6 r ₁ = 287.7208 d ₁ = 0.9000 n _d1 = 1.80610 ν _d1 = 40.92 r ₂ = 8.5536 (aspherical surface) d ₂ = 2.1000 r ₃ = ∞ d ₃ = 8.4000 r ₄ = ∞ d ₄ = 0.1500 r ₅ = _{16.2840 d 5 = 1.7000 n d5 =} 1.73400 ν d5 = 51.47 r 6 = -87.4861 d 6 = D6 r 7 = -12.9420 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 = 47.4193 d ₉ = D 9 r ₁₀ = ∞ (aperture) d ₁₀ = 0 r ₁₁ = 8.0948 (aspherical surface) d ₁₁ = 1.9000 n _{d 11} = 1.74320 ν _{d 11} = 49.34 r ₁₂ = -18.2182 ( Aspherical surface) d ₁₂ = 0.1500 r ₁₃ = 6.1759 d ₁₃ = 2.5000 n _d13 = 1.74320 ν _d13 = 49.34 r ₁₄ = -20.0000 d ₁₄ = 0.7000 n _d14 = 1.84666 ν _d14 = 23.78 r ₁₅ = 3.1875 d ₁₅ = D15 r ₁₆ = ∞ (variable transmittance means or shutter _{position) d 16 = 3.6250 r 17 =} 15.0796 d 17 = 1.8000 n d17 = 1.57099 ν d17 = 50.80 r 18 = -14.9993 ( aspherical _{d 18 = 0.8750 r 19 = ∞} d 19 = 0.7500 n d19 = 1.51633 ν d19 = 64.14 r 20 = ∞ d 20 = D20 r 21 = ∞ ( imaging plane) d ₂₁ = 0

Aspherical coefficient second surface K = 0 A ₂ = 0 A ₄ = -2.9216 × 10 ^-4 A ₆ = 2.7058 × 10 ^-6 A ₈ = -1.0174 × 10 ^-7 A ₁₀ = 0 11th surface K = 0 A ₂ = 0 A ₄ = -5.4278 x 10 ^-4 A ₆ = -4.6715 x 10 ^-5 A ₈ = -4.4895 x 10 ^-7 A ₁₀ = 0 12th surface K = 0 A ₂ = 0 A ₄ = -1.6294 × 10 ^-4 A ₆ = -5.7124 × 10 ^-5 A ₈ = 7.4143 × 10 ^-7 A ₁₀ = 0 18th surface K = 0 A ₂ = 0 A ₄ ＝ 5.3686 × 10 ^-4 A ₆ ＝ 7.2927 × 10 ^-6 A ₈ = -2.1769 x 10 ^-6 A ₁₀ = 0

Zoom data When D0 (distance from object to first surface) is ∞               Wide-angle end Mid-telephoto end f (mm) 4.00038 6.92729 12.00247 Fno. 2.5763 3.4177 5.0414 D0 ∞ ∞ ∞ D6 0.89975 3.74456 0.90123 D9 11.36100 4.89989 0.90214 D15 1.36578 4.98133 11.82310 D20 1.00000 1.00000 1.00000

Seventh Embodiment FIG. 22 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, and 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. 23 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. 22, the electronic image pickup apparatus of the seventh embodiment has a zoom lens and a CCD which is an electronic image pickup element in order from the object side. In FIG. 22, 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 a fourth lens group G4. First lens group G
1, in order from the object side, a negative meniscus lens L1 ₁ with a convex surface facing the object side, a reflecting optical element R1 having a reflecting surface for bending the optical path, a positive meniscus lens with a convex surface facing the object side L1 ₂ ' It consists of and. The reflective optical element R1 is configured as a surface mirror that bends the optical path by 90 °. Further, the reflecting surface of the surface mirror is configured to be variable in shape, and the focusing operation is performed by changing the shape of the reflecting surface. 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,
It has a negative refracting power as a whole. The third lens group G3 includes
It is composed of, in order from the object side, a biconvex positive lens L3 ₁ and a cemented lens of a biconvex positive lens L3 ₂ ′ and a biconcave negative lens L3 ₃ ′, and has a positive refracting power as a whole. . The fourth lens group G4 is composed of a positive meniscus lens L4 ₁ having a concave surface facing the object side.

When zooming from the wide-angle end to the telephoto end, the positions of the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 reciprocates in a convex locus toward the image side. (That is, after moving to the image side to temporarily widen the distance to the first lens group G1 and then moving to the object side to reduce the distance to the first lens group G1), the third lens group G3 is used as an aperture stop. It moves only to the object side together with S. Also,
The positions of the first lens group G1 and the fourth lens group G4 are fixed even during the focusing operation. The aspherical surface is the first lens group G1.
The image-side surface of the negative meniscus lens L1 ₁ with the convex surface facing the object side, and the biconcave negative lens L3 ₃ ′ in the third lens group G3
_On the image side of the positive meniscus lens L4 ₁ having a concave surface facing the object side constituting 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 = 179.9734 d ₁ = 0.9000 n _d1 = 1.80610 ν _d1 = 40.92 r ₂ = 8.7645 (aspherical surface) d ₂ = 1.8000 r ₃ = ∞ d ₃ = 8.4000 r ₄ = ∞ d ₄ = 0.1500 r ₅ = 12.7792 d ₅ = 1.7000 n _d5 = 1.73400 ν _d5 ＝ 51.47 r ₆ ＝ 112.8775 d ₆ ＝ D6 r ₇ ＝ -10.6752 d ₇ ＝ 0.7000 n _d7 ＝ 1.72916 ν _d7 ＝ 54.68 r ₈ ＝ 11.0000 d ₈ ＝ 1.35004 666 _d8 ν _d8 = 23.78 r ₉ = 57.4122 d ₉ = D 9 r ₁₀ = ∞ (aperture) d ₁₀ = 0 r ₁₁ = 7.5375 (aspherical surface) d ₁₁ = 2.1000 n _{d 11} = 1.74320 ν _{d 11} = 49.34 r ₁₂ = -14.2059 (non Spherical surface) d ₁₂ = 0.1500 r ₁₃ = 5.4153 d ₁₃ = 2.1000 n _d13 = 1.74300 v _d13 = 51.47 r ₁₄ = -25.0000 d ₁₄ = 0.7000 n _d14 = 1.84666 v _d14 = 23.78 r ₁₅ = 2.8519 d ₁₅ = 1.6250 r ₁₆ ∞ (variable transmittance means or shutter _{position) d 16 = D16 r 17 =} -13.9912 d 17 = 1.6000 n d17 = 1.68893 ν d17 = 31.07 r 18 = -6.0274 ( aspherical _{d 18 = 0.8750 r 19 = ∞} d 19 = 0.7500 n d19 = 1.51633 ν d19 = 64.14 r 20 = ∞ d 20 = D20 r 21 = ∞ ( imaging plane) d ₂₁ = 0

Aspheric coefficient 2nd surface K = 0 A ₂ = 0 A ₄ = -2.6082 × 10 ^-4 A ₆ = 2.1812 × 10 ^-6 A ₈ = -9.2869 × 10 ^-8 A ₁₀ = 0 11th surface K = 0 A ₂ = 0 A ₄ = -4.8935 × 10 ^-4 A ₆ = -8.2602 × 10 ^-5 A ₈ = -1.6349 × 10 ^-6 A ₁₀ = 0 12th surface K = 0 A ₂ = 0 A ₄ = 1.4604 x 10 ^-4 A ₆ = -1.1504 x 10 ^-4 A ₈ = 1.4427 x 10 ^-6 A ₁₀ = 0 18th surface K = 0 A ₂ = 0 A ₄ = 1.6159 x 10 ^-3 A ₆ = -3.5024 x 10 ^-5 A ₈ = -2.8372 x 10 ^-7 A ₁₀ = 0

Zoom data When D0 (distance from object to first surface) is ∞               Wide-angle end Mid-telephoto end f (mm) 4.00059 6.92436 12.00132 Fno. 2.5241 3.3645 4.9430 D0 ∞ ∞ ∞ D6 0.89971 3.35716 0.90160 D9 10.02202 4.33848 0.90196 D16 2.97093 6.19241 12.08905 D20 1.00000 1.00000 1.00000

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

[0108]

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 addition to the above table, the horizontal pixel pitch a of the electronic image sensor is 1.8.
Values from 3 to 3.5 may be used. In addition, in the table, the bending point is the virtual surface front surface (third part) of the lenslator.
The distance from the surface) (the distance between the 45-degree reflecting surface and the optical axis). Further, in each of the above-described embodiments, the reflecting surface of each numerical data is a plane when focusing on an infinite object point, and a concave surface when focusing on an object at a short distance. It should be noted that, from the principle of shape variation, it is preferable to make the surface slightly concave even when focusing on an object point at infinity, and to make the surface concave when the object point at short distance is focused. Further, the radius of curvature of the reflecting surface is at the intersection with the optical axis and may be an aspherical surface.

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. 24 is a diagram showing an example of a pixel array of the electronic image pickup device used in each embodiment of the present invention.
Pixels of (blue) or pixels of four colors of cyan, magenta, yellow, and green (green) (FIG. 27) 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 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. On the exit surface side of the CCD cover glass CG coated with the near-infrared cut coat, or on the exit surface side of the other lens coated 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 the deterioration of the image due to the color on the short wavelength side, which is difficult to be recognized by human eyes, to be 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. 27, 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 filters are substantially the same and adjacent pixels do not correspond to the same type of color filters.
This allows more faithful color reproduction.

The complementary color mosaic filter is specifically
As shown in FIG. 27, it is preferable that the color filter is composed of at least four types of color filters, and the characteristics of the four types of color filters are as follows. 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. 28 shows an example of each wavelength characteristic in each of the above embodiments. The green color filter G is
It has a spectral intensity beak at a wavelength of 525 nm. The yellow color filter Y _e has a peak of spectral intensity at a wavelength of 555 nm. The cyan color filter C has a peak of spectral intensity at a wavelength of 510 nm. The magenta color filter M has a wavelength of 445 nm and a wavelength of 620 n.
It has a peak at m. Further, in the respective color filters at the wavelength of 530 nm, G is 99%, Y _e is 95%, C is 97%, and M is 3 with respect to the respective spectral intensity peaks.
It is 8%.

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

Further, in the numerical data of each of the above-mentioned examples, the distance (d ₈ ) from the position of the aperture stop S to the convex surface of the lens on the next image side is 0 is that the vertex of the convex surface of the lens is This means that the position is equal to the intersection of the perpendicular line drawn from the aperture stop S to the optical axis and the optical axis. Although the diaphragm S is a flat plate in each of the above embodiments, a black-painted member having a circular opening may be used as another configuration. Alternatively, a funnel-shaped stop as shown in FIG. 29 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 image-side air space of the third lens group G3. Is designed to be able to. As for the light quantity adjusting means, as shown in FIG. 30, an ND having a transparent surface or a hollow opening and 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.

FIG. 31 shows this specific example. 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. 30 that allows the brightness to be adjusted in three stages is arranged. The turret 10 has an aperture having a transmittance of 100%, an ND filter having a transmittance of 50%, an ND filter having a transmittance of 25%, and a transmittance of 12.5 in terms of transmittance for a wavelength of 550 nm in a region that transmits an effective light flux. % Of the ND filters are provided in the openings 1A, 1B, 1C and 1D. Then, by rotating the turret 10 around the rotation axis 11, one of the openings is arranged on the optical axis between the lenses, which is a space different from the aperture position, to adjust the light amount.

Further, as the light quantity adjusting means, as shown in FIG. 32, a filter surface capable of adjusting the light quantity may be provided so as to suppress the unevenness of the light quantity. The filter surface of FIG. 32 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. 33, a TN liquid crystal cell is sandwiched from both sides by two parallel flat plates having a transparent electrode and a polarizing film whose polarization direction matches.
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. 34 is a schematic diagram showing an example of a rotary focal plane shutter which is one of the focal plane shutters for adjusting the light receiving time applicable to the electronic image pickup apparatus according to each embodiment of the present invention. ) Is a back view, (b) is a front view, and (a) to (d) of FIG. 35 are views of the rotary shutter curtain B viewed from the image side. In FIG. 34, 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 apparatus of the present invention, the shutter substrate A is arranged immediately before the image plane or in an arbitrary optical path. Further, the shutter substrate A is provided with an opening A1 that transmits an effective light flux of the optical system. The rotary shutter curtain B is formed in a substantially semicircular shape. The rotary shaft C of the rotary shutter curtain is integrated with the rotary shutter curtain B. Also, the rotation axis C
Rotate with respect to the shutter substrate A. The rotating shaft C is connected to the gears D1 and D2 on the surface of the shutter substrate A. The gears D1 and D2 are connected to a motor (not shown). Then, by driving a motor (not shown), the rotary shutter curtain B is rotated about the rotation axis C through the gears D2, D1 and the rotation axis C in the order of FIGS. 35 (a) to (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.
These shutters and variable transmittance filters are, for example, the first of the first embodiment in the above-described embodiment of the present invention.
It is arranged on 6 sides. Note that these light amount adjusting means may be arranged at other positions as long as they are different from the above-mentioned aperture stop.

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

Next, an example of the structure of a variable mirror applicable as a reflective optical element having a reflecting surface for bending the optical path in the zoom lens of the present invention will be described. FIG. 36 is a schematic configuration diagram showing an embodiment of a deformable mirror 409 applicable as a reflective optical element having a reflecting surface for bending the zoom lens of the present invention. First, the variable optical characteristic mirror 409
The basic configuration of will be described.

The deformable mirror 409 includes a thin film (reflection surface) 409a made of aluminum coating or the like and a plurality of electrodes 40.
9b is a variable shape mirror having optical characteristics (hereinafter, simply referred to as a variable shape mirror), 411 is a plurality of variable resistors respectively connected to the respective electrodes 409b, and 414 is a plurality of variable resistors 411. Arithmetic unit for controlling resistance value, 4
Reference numerals 15, 416 and 417 are a temperature sensor, a humidity sensor and a distance sensor, respectively, which are connected to the arithmetic unit 414, and these are arranged as shown in the figure to form one optical device.

The surface of the deformable mirror need not be a flat surface,
In addition to spherical surfaces and rotationally symmetric aspherical surfaces, spheres decentered with respect to the optical axis, planes, rotationally symmetric aspherical surfaces, aspherical surfaces having symmetry planes, aspherical surfaces having only one symmetry surface, and aspheric surfaces having no symmetry surface. It may have any shape such as a free-form surface, a surface having non-differentiable points or lines, and may be a reflective surface or a refracting surface as long as it has some influence on light. Hereinafter, these surfaces are collectively referred to as an extended curved surface.

The shape of the reflecting surface of the deformable mirror is preferably a free-form surface. This is because the aberration can be easily corrected, which is advantageous. The free-form surface used in the present invention is defined by the following formula. The Z-axis of this definition formula becomes the axis of the free-form surface.

[0135] Here, the first term of the equation (a) is a spherical term, and the second term is a free-form surface term. M is a natural number of 2 or more. In the spherical term, c: curvature of vertex k: conic constant (cone constant) r = √ (X ² + Y ² ).

The free-form surface term is However, Cj (j is an integer of 2 or more) is a coefficient. Generally, the free-form surface does not have a symmetry plane on both the XZ plane and the YZ plane, but by setting all odd-order terms of X to 0, a symmetry plane parallel to the YZ plane. Is a free-form surface with only one. In addition, by setting all the odd-numbered terms of Y to 0, a free-form surface having only one plane of symmetry parallel to the XZ plane is obtained.

As shown in FIG. 36, the deformable mirror of this embodiment has a piezoelectric element 4 between a thin film 409a and an electrode 409b.
09c is interposed and these are provided on the support base 423. Then, by changing the voltage applied to the piezoelectric element 409c for each electrode 409b, the piezoelectric element 40
9c partially expands and contracts to form a thin film 409a.
The shape of can be changed. Electrode 4
The shape of 09b may be concentric division as shown in FIG. 37, or may be rectangular division as shown in FIG. 38, and any other appropriate shape can be selected.
In FIG. 36, reference numeral 424 is a shake (blur) sensor connected to the arithmetic unit 414, which detects, for example, a shake of a digital camera and deforms the thin film 409a so as to compensate the image disturbance due to the shake. The voltage applied to the electrode 409b via 414 and the variable resistor 411 is changed. At this time, signals from the temperature sensor 415, the humidity sensor 416, and the distance sensor 417 are also taken into consideration at the same time, and focusing, temperature and humidity compensation, etc. are performed. In this case, since stress is applied to the thin film 409a due to the deformation of the piezoelectric element 409c, it is preferable that the thin film 409a be made thicker to some extent to have a corresponding strength.

FIG. 39 is a schematic constitutional view showing still another embodiment of the deformable mirror 409 applicable as a reflecting optical element having a reflecting surface for folding the zoom lens of the present invention. The deformable mirror of this embodiment is composed of a thin film 409a and an electrode 40.
Two piezoelectric elements 409c and 409 in which the piezoelectric element interposed between 9b is made of a material having opposite piezoelectric characteristics.
The deformable mirror differs from the deformable mirror of the embodiment shown in FIG. 36 in that the deformable mirror is constituted by c ′. That is, if the piezoelectric elements 409c and 409c 'are made of a ferroelectric crystal, the crystal axes are arranged so as to be opposite to each other. In this case, since the piezoelectric elements 409c and 409c 'expand and contract in the opposite directions when a voltage is applied, the force for deforming the thin film 409a becomes stronger than in the case of the embodiment shown in FIG. The advantage is that the shape can be changed significantly.

Examples of materials used for the piezoelectric elements 409c and 409c 'include barium titanate, Rossier salt,
Quartz crystals, tourmaline, potassium dihydrogen phosphate (KDP), ammonium dihydrogen phosphate (ADP), piezoelectric materials such as lithium niobate, polycrystals of the same, crystals of the same, PbZ
There are piezoelectric ceramics of solid solution of rO ₃ and PbTiO ₃ , organic piezoelectric materials such as polyvinyl difluoride (PVDF), and ferroelectric materials other than the above. In particular, organic piezoelectric materials have a small Young's modulus and undergo large deformation even at low voltage. Is possible, which is preferable. When using these piezoelectric elements, if the thickness is made nonuniform, the shape of the thin film 409a can be appropriately deformed in the above embodiment.

The materials of the piezoelectric elements 409c and 409c 'are polyurethane, silicon rubber, acrylic elastomer, PZT, PLZT, high-molecular piezoelectric material such as polyvinylidene fluoride (PVDF), vinylidene cyanide copolymer, vinylidene fluoride. A copolymer of ride and trifluoroethylene is used. If an organic material having piezoelectricity, a synthetic resin having piezoelectricity, an elastomer having piezoelectricity, or the like is used, a large deformation of the deformable mirror surface may be realized.

The piezoelectric element 409c shown in FIGS. 36 and 40 is used.
When an electrostrictive material such as acrylic elastomer or silicon rubber is used for the piezoelectric element 409c, the piezoelectric element 409c may have a structure in which another substrate 409c-1 and the electrostrictive material 409c-2 are attached.

FIG. 40 is a schematic constitutional view showing still another embodiment of the deformable mirror 409 applicable as a reflective optical element having a reflecting surface for bending the zoom lens of the present invention. In the deformable mirror of this embodiment, the piezoelectric element 409c is sandwiched between the thin film 409a and the electrode 409d, and the thin film 409 is formed.
A voltage is applied between a and the electrode 409d via a drive circuit 425 controlled by the arithmetic unit 414, and separately from this, an arithmetic unit is also applied to the electrode 409b provided on the support 423. A voltage is applied via a drive circuit 425 controlled by 414. Therefore, in this embodiment, the thin film 409a can be doubly deformed by the voltage applied between the electrode 409d and the electrostatic force generated by the voltage applied to the electrode 409b. There is an advantage that more deformation patterns are possible and the responsiveness is fast.

By changing the sign of the voltage between the thin film 409a and the electrode 409d, the deformable mirror can be deformed into a convex surface or a concave surface. In that case, a large deformation may be performed by the piezoelectric effect and a minute shape change may be performed by the electrostatic force. Further, the piezoelectric effect may be mainly used for the deformation of the convex surface, and the electrostatic force may be mainly used for the deformation of the concave surface. The electrode 4
09d may be composed of a plurality of electrodes like the electrode 409b. This state is shown in FIG. In the present application, the piezoelectric effect, the electrostrictive effect, and the electrostrictive are all referred to as the piezoelectric effect. Therefore, the electrostrictive material is also included in the piezoelectric material.

FIG. 41 is a schematic structural view showing still another embodiment of the deformable mirror 409 applicable as a reflective optical element having a reflecting surface for folding the zoom lens of the present invention. The deformable mirror of this embodiment is configured so that the shape of the reflecting surface can be changed by utilizing electromagnetic force.
3, a permanent magnet 426 is mounted on the inner bottom surface, and a peripheral portion of a substrate 409e made of silicon nitride, polyimide or the like is mounted and fixed on the top surface, and the surface of the substrate 409e is made of a metal coat such as aluminum. A thin film 409a is attached to form a deformable mirror 409. Board 4
A plurality of coils 427 are provided on the lower surface of 09e, and each of these coils 427 is connected to the arithmetic unit 414 via a drive circuit 428. Therefore,
An appropriate current is supplied from each drive circuit 428 to each coil 427 by the output signal from the arithmetic unit 414 corresponding to the change of the optical system obtained in the arithmetic unit 414 by the signal from each sensor 415, 416, 417, 424. Then, each coil 427 is repelled or attracted by the electromagnetic force working between the permanent magnet 426 and the substrate 409e.
And the thin film 409a is deformed.

In this case, each coil 427 can be made to flow a different amount of current. Further, the number of the coils 427 may be one, or the permanent magnet 426 may be provided on the substrate 40.
9e may be attached and the coil 427 may be provided on the inner bottom surface side of the support base 423. The coil 427 may be formed by a method such as lithography, and the coil 42
An iron core made of a ferromagnetic material may be inserted in 7.

In this case, the winding density of the thin film coil 427 is
As shown in FIG. 42, the substrate 409e and the thin film 409a can be deformed as desired by changing the position. Further, the number of the coils 427 may be one, or an iron core made of a ferromagnetic material may be inserted into these coils 427.

FIG. 43 is a schematic constitutional view showing still another embodiment of the deformable mirror 409 applicable as a reflective optical element having a reflecting surface for folding the zoom lens of the present invention. In the figure, 412 is a power supply. In the deformable mirror of this embodiment, the substrate 409e is made of a ferromagnetic material such as iron,
The thin film 409a as a reflection film is made of aluminum or the like. In this case, since it is not necessary to provide the thin film coil, the structure is simple and the manufacturing cost can be reduced. If the power switch 413 is replaced with a switch for switching and opening / closing the power, the direction of the current flowing through the coil 427 can be changed, and the shapes of the substrate 409e and the thin film 409a can be freely changed. FIG. 44 shows the arrangement of the coil 427 in this embodiment, and FIG. 45 shows the coil 42.
7 shows another example of the arrangement shown in FIG.
It can also be applied to the embodiment shown in FIG. It should be noted that FIG. 46 shows the coil 427 in the embodiment shown in FIG.
45 shows the arrangement of the permanent magnets 426 which is suitable when the arrangement shown in FIG. That is, if the permanent magnets 426 are radially arranged as shown in FIG.
Subtle modifications can be applied to the substrate 409e and the thin film 409a as compared with the embodiment shown in FIG. Further, in the case of deforming the substrate 409e and the thin film 409a by using the electromagnetic force (the embodiment of FIGS. 41 and 43), there is an advantage that the voltage can be driven at a lower voltage than in the case of using the electrostatic force.

Although some examples of the deformable mirror have been described above, two or more kinds of forces may be used to deform the shape of the mirror, as shown in the example of FIG. That is, the deformable mirror may be deformed by simultaneously using two or more of electrostatic force, electromagnetic force, piezoelectric effect, magnetostriction, fluid pressure, electric field, magnetic field, temperature change, electromagnetic wave and the like. That is, if the variable optical characteristic element is manufactured by using two or more different driving methods, a large deformation and a minute deformation can be realized at the same time, and an accurate mirror surface can be realized.

FIG. 47 shows an image pickup system using a deformable mirror 409 applicable as a reflective optical element having a reflecting surface for folding a zoom lens according to still another embodiment of the present invention, for example, a digital camera of a mobile phone. FIG. 1 is a schematic configuration diagram of an imaging system used in a capsule endoscope, an electronic endoscope, a digital camera for personal computer, a digital camera for PDA, and the like. In the image pickup system of the present embodiment, the reflective optical element R1 in the optical configuration shown in the first embodiment is composed of a deformable mirror 409. The zoom lens, the CCD 408 which is an electronic image pickup device, and the control system 103 constitute one image pickup unit 104. In the image pickup unit 104 of the present embodiment, the light from the object passing through the negative meniscus lens L1 ₁ having the convex surface facing the object side is deformed by the deformable mirror 4
09, the biconvex positive lens L1 ₂ and the second lens group G
2, the third lens group G3, the fourth lens group G4, the CCD cover glass CG, and the CCD 408 which is a solid-state image sensor.
Image on. The deformable mirror 409 is a kind of variable optical characteristic optical element and is also called a variable focus mirror.

According to the present embodiment, even if the object distance changes, the deformable mirror 409 can be deformed for focusing, and it is not necessary to drive the lens with a motor or the like, and the size and weight can be reduced. Excellent in low power consumption.
The image pickup unit 104 can be used in all the embodiments as the image pickup system of the present invention. In addition, the deformable mirror 4
By using a plurality of 09, it is possible to create an image pickup system and an optical system for zooming and zooming. Incidentally, in FIG. 47, the control system 103
The example of the configuration of the control system including the step-up circuit of the transformer using the coil is shown in FIG. In particular, it is possible to reduce the size by using a laminated piezoelectric transformer. The booster circuit can be used for all the deformable mirrors using electricity according to the present invention, but is particularly useful for the deformable mirrors when electrostatic force or piezoelectric effect is used. In order to focus with the deformable mirror 409, for example, an object image is formed on the solid-state image sensor 408,
It is sufficient to find a state in which the high frequency component of the object image is maximized while changing the focal length of the deformable mirror 409. To detect the high frequency component, a processing circuit including a microcomputer or the like may be connected to the solid-state image sensor 408, and the high frequency component may be detected therein.

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.

48 to 50 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 the digital camera, and FIG. 48 is the digital camera 40.
5 is a front perspective view showing the external appearance of FIG.
Reference numeral 0 is a cross-sectional view showing the configuration of the digital camera 40. Note that the digital camera shown in FIG. 50 has a configuration in which the imaging optical path is bent in the long side direction of the finder.
The observer's eyes at 0 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. 50, a plane parallel plate is arranged as the cover member 50, but a lens having power may be used.

Next, FIGS. 51 to 53 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. 51 shows a personal computer 30
0 is a front perspective view with the cover open, FIG.
0 is a sectional view of the taking optical system 303, and FIG. 53 is a side view of FIG.

As shown in FIGS. 51 to 53, 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. 51 shows an image 305 taken by the operator as an example. Also, this image 305
It is also possible to display it on a personal computer of a communication partner from a remote place via the processing means and the Internet or a telephone.

Next, FIG. 54 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. 54 (a) is a front view of the mobile phone 400, FIG. 54 (b) is a side view, and FIG. 54 (c) is a cross-sectional view of the photographing optical system 405. As shown in FIGS. 54 (a) to 54 (c), the mobile phone 400 has a microphone unit 401 for inputting the voice of the operator as information, a speaker unit 402 for outputting the voice of the other party of the call, and the operator inputs information. An input dial 403 for inputting, and a monitor 404 for displaying information such as a photographed image of the operator himself / herself or a communication partner and a telephone number.
The image pickup optical system 405, an antenna 406 for transmitting and receiving communication radio waves, and a processing unit (not shown) for processing image information, communication information, input signals, and the like. Here, the monitor 404 is a liquid crystal display element. Further, in the drawing, the arrangement position of each component is not particularly limited to these. The photographing optical system 405 has an objective lens 112, which is disposed on the photographing optical path 407 and includes, for example, the optical path bending zoom lens according to the first embodiment of the present invention, and an image pickup element chip 162 that receives an object image. . These are built into the mobile phone 400.

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

The object image received by the imaging element chip 162 is input to the 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 and the electronic image pickup apparatus having the same according to the present invention have the following features in addition to the invention described in the claims.

(1) 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 item 1. F ≧ a / (1 μm)

(2) The inner diameter of the aperture stop that determines the open F value is fixed, and a lens having a convex surface facing the stop is provided immediately before or immediately after the stop, and the optical axis and the aperture stop are provided. The point of intersection with a perpendicular line from the above to the optical axis is located within 0.5 mm from the inside of the lens or the surface vertex of the convex surface, according to the above (1).

(3) The electronic image pickup device according to (2), wherein the intersection is located inside or inside the surface of the lens.

(4) 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 provided in a space different from the space in which the diaphragm is arranged. The electronic imaging device according to any one of the above (1) to (3), which is arranged in the optical path.

(5) A shutter for adjusting a light receiving time of a light beam guided to the electronic image pickup device is provided, and the shutter is arranged in an optical path of a space different from a space in which the diaphragm is arranged. The electronic imaging device according to any one of (1) to (4) above.

(6) The electronic image pickup device according to any one of (1) to (5) 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.

(7) All the medium boundary surfaces arranged between the zoom lens and the image pickup surface are substantially flat surfaces,
Moreover, there is no spatial frequency conversion action like an optical low-pass filter, and the above (1) to (6).
The electronic imaging device according to any one of (5).

(8) The third lens group is composed of three lenses, and the three lenses are 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. It is constituted or constituted by one lens component which consists of three cemented lenses, and when it changes from a wide-angle end to a telephoto end, it moves only to the object side. The zoom lens according to any one of 1.

(9) The zoom lens according to claim 1 or 2, wherein the following conditional expression is satisfied. 0.9 <−f11 / √ (fw · fT) <2.4 1.6 <f12 / √ (fw · fT) <3.6 where f11 is the focal length of the negative lens component in the most object side lens group, f12 is the focal length of the positive lens component in the lens group closest to the object, 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) An electronic image pickup apparatus having the zoom lens described in (9) above and an electronic image pickup element arranged on the image side thereof, and satisfying the following conditional expression. 1.4 <d / L <3.0 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.

(11) The electronic image pickup device according to (10), wherein the negative lens component of the most object side lens unit is composed of a negative single lens, and the following conditional expression is satisfied: 26 <ν1N −0.1 <√ (fw · fT) / f1 <0.6 where ν1N is the Abbe number of the medium of the negative single lens in the lens group on the most object side on the d-line basis, and f1 is the most object side The focal length of the lens group, 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.

(12) The negative lens component in the most object side lens unit is a negative single lens, and the positive lens component is a positive single lens.
Alternatively, the zoom lens described in 2.

(13) The first lens group has a positive refractive power, the third lens group moves only to the object side during zooming, and the most image side lens group includes an aspherical surface, and The zoom lens according to claim 3, wherein the zoom lens is fixed during zooming.

(14) 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) <2.0 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 the combined focal length of the third lens group and thereafter at the wide-angle end when focusing on an object point at infinity, fw is the focal length of the entire system at the wide-angle end of the zoom lens, and fT is the entire focal length at the telephoto end of the zoom lens. The focal length.

(15) The third lens group is composed of three lenses, and the three lenses are arranged in order from the object side.
A single lens and a cemented lens component in which a positive lens and a negative lens are cemented together.
5. The zoom lens according to any one of (8) above.

(14) The third lens group is composed of three lenses, and the three lenses are arranged in order from the object side.
3. A cemented lens component obtained by cementing a positive lens and a negative lens, and a single lens.
5. The zoom lens according to any one of (8) above.

(17) The third lens group is composed of three lenses, and the three lenses are arranged in order from the object side.
The zoom lens according to any one of (2) to (5) above, which comprises a cemented lens component in which a positive lens, a negative lens, and a positive lens are cemented.

(18) The zoom lens described in (15) above, which satisfies the following conditional expression. 0.4 <R _C3 / R _C1 <0.8 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.

(19) The zoom lens described in (16) above, which satisfies the following conditional expression. 1.0 < _RC3 / _RC1 <10 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 the cemented lens component in the third lens group. Is the radius of curvature on the optical axis of the surface closest to the object.

(20) The zoom of (15) or (18) above
Including a lens and an electronic image pickup device arranged on the image side.
The electronic image pickup device is characterized by satisfying the following conditional expression.
Place -0.7 <L / R_C2  <0.1 15 <ν_CP  −ν_CN 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

(21) The zoom of (16) or (20) above
Including a lens and an electronic image pickup device arranged on the image side.
The electronic image pickup device is characterized by satisfying the following conditional expression.
Place -1.1 <L / R_C2  <0 15 <ν_CP  −ν_CN 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

(22) The zoom lens described in (17), which satisfies the following conditional expression. -4.0 <(R _CF + R _CR ) / (R _CF -R _CR ) <
Where R _CF is the radius of curvature of the most object-side surface of the triplet cemented lens component on the optical axis, and R _CR is the radius of curvature of the most image-side surface of the triplet cemented lens component on the optical axis. .

(23) The zoom lens described in (17) or (22), characterized by satisfying the following conditional expression. 0.6 <Dc / fw <1.8 where Dc is the distance on the optical axis from the most object side surface to the most image side surface of the triplet cemented lens component, and fw is at the wide-angle end of the zoom lens. This is the focal length of the entire system.

(24) The zoom lens described in any one of (17), (22), and (23), which satisfies the following conditional expression. 0.002 / mm ² <Σ | (1 / Rci)-(1 / Rca)
| ² <0.05 / mm ² , where Rci is the radius of curvature on the optical axis of the i-th cemented surface from the object side of the triplet cemented lens component, and Rca is Rca = m /
| Σ (1 / Rci) | (i = 1 ... m), where
m is the number of joint surfaces, 2.

(25) The zoom lens described in any one of (17), (22) to (24), which satisfies the following conditional expression. 5 × 10 ^-5 <Σ | (1 / νcj + 1)-(1 / νcj) | ²
<4 × 10 ⁻³ where νcj is the Abbe number of the medium based on the i-th d-line from the object side of the triplet cemented lens component, j = 1 ... n−1, where n is cemented The number of lenses is 3.

(26) The zoom lens described in any one of (17), (22) to (25), which satisfies the following conditional expression. 0.005 <Σ | ncj + 1-ncj | ² <0.5 where ncj is the refractive index of the medium at the i-th d-line reference from the object side of the triplet cemented lens component, j = 1 ... n-1 And
Here, n is 3, which is the number of lenses to be cemented.

(27) The zoom lens according to claim 1 or 2, wherein the negative lens component of the most object side lens unit is an aspherical surface.

(28) The zoom lens described in (27), which satisfies the following conditional expression. _{-2.5 <(R 1PF + R 1PR} ) / (R 1PF -R 1PR)
<0.6 However, R _1PF is the radius of curvature on the optical axis of the object side surface of the positive lens component of the most object side lens group, R _{1 PR} is on the optical axis of the image side surface of the positive lens component of the most object side lens unit Is the radius of curvature of.

(29) 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.

(30) The second lens group is a cemented lens component composed of two lenses, a negative lens and a positive lens, in order from the object side. (29)
Zoom lens described in.

(31) The zoom lens described in the above (30), characterized in that the following conditional expression is satisfied. _{-1.6 <(R 2F + R 2R} ) / (R 2F -R 2R) <
0.3 where R _2F is the radius of curvature on the optical axis of the most object-side surface of the second lens group (the cemented lens component), and R _2R is the most image-side surface of the second lens group (the cemented lens component) Is the radius of curvature on the optical axis of.

(32) The zoom lens satisfies the following conditional expression: (1) to (5), above (8),
The zoom lens according to any one of (9), (12) to (19), and (22) to (31). 1.8 <fT / fw 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.

(33) The full angle of view at the wide-angle end in the electronic image pickup device has a value of 55 degrees or more, (7), (10), (11), (20), (2).
The electronic imaging device according to any one of 1).

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

[0199]

According to the present invention, a reflective optical element such as a mirror is inserted as close as possible to the object side to bend the optical path (optical axis) of the optical system, especially the zoom lens system, and to satisfy various conditional expressions. Since it is configured to, zoom ratio, angle of view, F
While maintaining high optical specification performance such as value and small aberration, there is no startup time (lens extension time) to use the camera as seen in a retractable lens barrel, and it is waterproof.
It is also preferable in terms of dustproofness, and a camera having an extremely thin depth can be realized. In addition, unlike other zoom optical systems such as zoom lenses suitable for retractable lens barrels,
When the downsizing of the image pickup device is advanced, further downsizing and thinning of the camera can be advantageously promoted 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 sectional view taken along the optical axis showing the optical configuration of a second embodiment of the zoom lens used in the electronic imaging 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. 7 is a cross-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;
Shows the state at the wide-angle end, (b) at the middle, and (c) at the telephoto end.

FIG. 8 is a cross-sectional view taken along the optical axis showing an 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. 9 is a cross-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;
Shows the state at the wide-angle end, (b) at the middle, and (c) at the telephoto end.

FIG. 10 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 3 upon focusing on an object point at infinity, showing the state at the wide-angle end.

FIG. 11 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 3 upon focusing on an object point at infinity, showing an intermediate state.

FIG. 12 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification of the zoom lens of Example 3 upon focusing on an object point at infinity, showing the state at the telephoto end.

FIG. 13 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 present invention in a fourth example, showing a state at the time of bending when focusing on an object point at infinity at the wide-angle end. ing.

FIG. 14 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) shows the state at the wide-angle end, (b) shows the intermediate state, and (c) shows the state at the telephoto end.

FIG. 15 is a diagram showing spherical aberration, astigmatism, distortion, and chromatic aberration of magnification when the zoom lens of Example 4 is focused on an object point at infinity, showing the state at the wide-angle end.

FIG. 16 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 infinity, and shows a state in the middle.

FIG. 17 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. 18 is a cross-sectional view taken along the optical axis showing the optical configuration of a fifth embodiment of the zoom lens used in the electronic imaging 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. 19 is a 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. 20 is a sectional view taken along the optical axis showing the optical configuration of a sixth embodiment of a zoom lens used in an 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. 21 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens according to Example 6 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. 22 is a sectional view taken along the optical axis showing an optical configuration of a zoom lens used in an electronic image pickup apparatus according to a seventh 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. 23 is a sectional view taken along the optical axis showing the optical configuration of the zoom lens according to 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. 24 is an explanatory diagram showing an example of a pixel array of an electronic image sensor used in each example of the present invention.

FIG. 25 is a graph showing transmittance characteristics of an example of a near infrared sharp cut coat.

FIG. 26 shows transmittance characteristics of an example of a color filter provided on the exit surface side of a CCD cover glass CG coated with a near infrared cut coat or on the exit surface side of another lens provided with a near infrared cut coat. It is a graph.

FIG. 27 is a diagram showing a color filter arrangement of complementary color mosaic filters.

FIG. 28 is a graph showing an example of wavelength characteristics of a complementary color mosaic filter.

FIG. 29 is an explanatory diagram showing a modification of the diaphragm S used in the electronic image pickup apparatus according to each embodiment of the present invention.

FIG. 30 is an explanatory diagram showing an example of a light amount adjusting unit used in the electronic image pickup apparatus according to each embodiment of the present invention.

FIG. 31 is a perspective view showing a specific example of a state in which the light amount adjusting means shown in FIG. 30 is applied to the present invention.

FIG. 32 is an explanatory diagram showing another example of the light amount adjusting means applicable to the electronic imaging device according to each embodiment of the present invention.

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

FIG. 34 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 image pickup apparatus according to each embodiment of the present invention, and FIG. Back view, (b)
Is a front view.

35 (a) to 35 (d) are views showing how the rotary shutter curtain B shown in FIG. 34 rotates, as seen from the image plane side.

FIG. 36 is a deformable mirror 409 applicable as a reflective optical element having a reflecting surface for bending the zoom lens of the present invention.
It is a schematic block diagram which shows one Example.

37 is an explanatory diagram showing a form of an electrode used for the deformable mirror of the embodiment of FIG. 36. FIG.

38 is an explanatory diagram showing another form of the electrode used in the deformable mirror of the embodiment of FIG. 36. FIG.

FIG. 39 is a deformable mirror 409 applicable as a reflective optical element having a reflective surface for bending the zoom lens of the present invention.
It is a schematic block diagram which shows the other Example of this.

FIG. 40 is a deformable mirror 409 applicable as a reflective optical element having a reflecting surface for bending the zoom lens of the present invention.
It is a schematic block diagram which shows the other Example of this.

FIG. 41 is a deformable mirror 409 applicable as a reflective optical element having a reflecting surface for bending the zoom lens of the present invention.
It is a schematic block diagram which shows the other Example of this.

42 is an explanatory diagram showing a state of winding density of the thin film coil 427 in the embodiment of FIG. 41. FIG.

FIG. 43 is a deformable mirror 409 applicable as a reflective optical element having a reflecting surface for bending the zoom lens of the present invention.
It is a schematic block diagram which shows the other Example of this.

FIG. 44 is an explanatory diagram showing an arrangement example of the coil 427 in the embodiment of FIG. 43.

45 is an explanatory diagram showing another arrangement example of the coil 427 in the embodiment of FIG. 43.

FIG. 46 is a circuit diagram of the coil 42 in the embodiment shown in FIG.
FIG. 47 is an explanatory diagram showing an arrangement of permanent magnets 426 suitable when the arrangement of No. 7 is as shown in FIG. 45.

FIG. 47 is an imaging system using a deformable mirror 409 applicable as a reflective optical element having a reflecting surface for folding a zoom lens according to still another embodiment of the present invention, for example, a digital camera of a mobile phone, a capsule. Endoscope, electronic endoscope,
1 is a schematic configuration diagram of an image pickup system used in a digital camera for personal computer, a digital camera for PDA, and the like.

48 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 a digital camera, and is a front perspective view showing the appearance of the digital camera 40. FIG.

49 is a rear perspective view of the digital camera 40 shown in FIG. 48. FIG.

50 is a sectional view showing the structure of the digital camera 40 shown in FIG. 48.

FIG. 51 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.

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

53 is a side view of FIG. 51. FIG.

54A and 54B are diagrams showing a mobile phone 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, where FIG. 54A is a front view of the mobile phone 400 and FIG.
(a) is a side view and (c) is a cross-sectional view of the photographing optical system 405.

[Explanation of symbols]

A shutter substrate A1 substrate opening B rotary shutter curtain C rotary shutter curtain rotation axes D1, D2 gears CG CCD cover glass E observer eye G1 first lens group G2 second lens group (first moving lens group) G3 3 lens groups (second moving lens group) G4 4th lens group I Imaging surface L1 ₁ Negative meniscus lens L1 ₂ with convex surface facing the object side Positive lens L2 ₁ Biconcave negative lens L2 _{2 With} convex surface facing the object side a positive meniscus lens L3 ₁ biconvex positive lens L3 ₂ biconcave negative lens L3 ₂ 'biconvex positive lens L3 ₃ positive meniscus lens convex toward the object side L3 _3' biconcave negative lens L4 ₁ object side a concave surface facing the Positive meniscus lens L4 ₁ ′ Biconcave negative lens L4 ₁ ″ Negative meniscus lens L4 ₁ ″ ″ Convex surface facing object side Positive meniscus lens L4 ₁ ″ ″ Biconvex surface facing convex surface toward object side Positive lens L4 ₂ Biconvex positive lens R1 Reflective optical element S Aperture diaphragms 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 Image pickup device chip 166 Terminal 300 Personal computer 301 Keyboard 302 Monitor 303 Photographing optical system 304 Photographing optical path 305 Image 400 Mobile phone 401 Microphone section 402 Speaker section 403 Input dial 404 Monitor 4 05 Photographing optical system 406 Antenna 407 Photographing optical path 408 Solid-state image sensor 409b, 409d Electrode 409c-2 Electrostrictive material 409 Optical property variable shape mirror 409a Thin film 409c, 409c 'Piezoelectric element 409c-1, 409e Substrate 411 Variable resistor 412 Power supply 413 Power switch 414 Calculation device 415 Temperature sensor 416 Humidity sensor 417 Distance sensor 423 Support stand 424 Shake sensor 425, 428 Drive circuit 426 Permanent magnet 427 Coil

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[Procedure amendment]

[Submission date] May 15, 2002 (2002.5.1)
5)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

Further, the second zoom lens according to the invention comprises, in order from the object side, comprises a first lens group as a most object-side lens group fixed, the negative refractive power upon zooming optical during zooming A second lens group as a first moving lens group that moves along the axis, a third lens group as a second moving lens group that has a positive refractive power and moves along the optical axis during zooming, and the most image and a most image-side lens group disposed on a side, the first lens group, perforated in order from the object side, a negative lens component, a front surface mirror having a reflecting surface for bending the optical path, a positive lens component Then
The reflective surface is variable in shape.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03B 17/17 G03B 3/04 H04N 5/225 F term (reference) 2H041 AA11 AB14 AB38 AC06 AZ02 AZ05 2H051 AA00 FA07 GB01 2H087 KA01 LA02 PA06 PA19 PB08 QA02 QA07 QA17 QA21 QA26 QA32 QA41 QA46 RA01 SA63 SA64 SA72 SA75 SB03 SB13 SB24 SB32 TA01 TA03 TA08 2H101 FF08 5C022 AC42 AC54 AC65 AC66 AC69 AC74 AC78

Claims (6)

[Claims] 1. A most object side lens unit 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. And a first moving lens group and a second moving lens group which are located between the most object side lens group and the most image side lens group, and which move on the optical axis during zooming. At least, the most object side lens group, in order from the object side, a negative lens component, a surface mirror having a reflecting surface for bending the optical path,
A zoom lens, comprising a positive lens component, wherein the most image side lens group has at least one aspherical surface. 2. A first lens unit, which is composed of a positive lens component in order from the object side and is a fixed most object side lens unit at the time of zooming, has a negative refracting power, and moves on the optical axis at the time of zooming. A second lens group as a first moving lens group, a third lens group as a second moving lens group having a positive refracting power and moving on the optical axis at the time of zooming, and arranged at the most image side. The first lens group has, in order from the object side, a negative lens component and a surface mirror having a reflecting surface for bending the optical path, and the reflecting surface has a variable shape. A zoom lens characterized in that 3. When zooming from a wide-angle end to a telephoto end when focusing on an object point at infinity, the second lens group reciprocates along an optical axis along a convex locus toward the image side. Claim 2
Zoom lens described in. 4. The zoom lens according to claim 1, wherein the focusing operation is performed by changing the shape of the reflecting surface. 5. The variable resistance value of the variable resistor, wherein the reflective surface is formed of a thin film coated with a metal or a dielectric, and the thin film is connected to a power source through a plurality of electrodes and a variable resistor. The zoom lens according to any one of claims 1 to 4, further comprising: an arithmetic unit that controls the distribution of the electrostatic force applied to the thin film, thereby changing the shape of the reflecting surface. . 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.