JP2003107356A - Optical path bending zoom optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical path bending zoom optical system which can be mounted on a small digital still camera, etc., an optical axis of which is bent for being thin and also allows a bend prism to have power. SOLUTION: In this optical path zoom optical system consisting of at least a first lens group G1 having negative refracting power, a second lens group G2 having positive refracting power, and succeeding lens group G3 and G4 from an object side in turn and including at least one lens group the second lens group G2 and being moved along the axis in performing variable power from a wide angle end to a telephoto end, the first lens group G1 has a prism P including at least one surface of a reflection surface, an incident surface and an outgoing surface for bending the optical path, and at least one between the incident surface of the prism P and the outgoing surface is a curved surface being a rotational symmetry with respect to the optical axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical path bending zoom optical system, and more particularly to a zoom system in which an optical path bending prism is arranged in order to realize thinning in the depth direction of a digital camera, a portable terminal or the like having the zoom optical system. It relates to an optical system.

[0002]

2. Description of the Related Art A compact camera using an electronic image pickup device such as a CCD or an image forming optical system built in a mobile terminal, a mobile phone or the like is strongly required to be miniaturized, particularly thin.

Under such circumstances, Japanese Patent Laid-Open No. 10-20191 discloses that a triangular prism having a plano-convex lens cemented with each other is arranged between groups of four-group zoom lenses to bend the optical path for compactness.

Although not a zoom lens, an optical path bending prism of an optical path bending optical system is provided with power (refractive power, divergence power) as disclosed in Japanese Patent Laid-Open No. 9-2112.
No. 87 and JP-A-10-239594 are known.

[0005]

However, in the case of Japanese Patent Laid-Open No. 10-20191, it is difficult to reduce the thickness because the prism is arranged after the diaphragm.

Further, as disclosed in Japanese Patent Laid-Open No. 9-212187 and Japanese Patent Laid-Open No. 10-239594, in which the prism has power, as described above, it is not a zoom lens, and
From the viewpoint of downsizing and thinning of the optical system, the prism does not have power.

The present invention has been made in view of such a situation of the prior art, and an object thereof is to provide a thin zoom optical system which can be mounted on a small digital still camera, a mobile terminal, etc. An object is to provide an optical path bending zoom optical system in which an optical axis is bent and a bending prism has power.

[0008]

A first optical path bending zoom optical system according to the present invention which achieves the above-mentioned object is at least:
When zooming from the wide-angle end to the telephoto end, the first lens group having a negative refractive power, the second lens group having a positive refractive power, and at least one lens group after that are arranged in order from the object side. In a zoom optical system including at least one lens group that includes the second lens group and moves along the optical axis, the first lens group includes at least one reflecting surface for bending an optical path, and an incident surface. It has a prism including a surface and an exit surface, and at least one of the entrance surface and the exit surface of the prism is a curved surface rotationally symmetric with respect to the optical axis.

A second optical path bending zoom optical system of the present invention has a negative refracting power at least in order from the object side,
A first lens group including at least one prism having a negative refractive power, a second lens group having a positive refractive power, and at least one lens group after that, when zooming from the wide-angle end to the telephoto end. In the zoom optical system including at least one lens group that moves along the optical axis including the second lens group, the prism includes at least one reflecting surface for bending an optical path, and an incident surface. And an exit surface, and at least one of the entrance surface and the exit surface is a curved surface.

In the third optical path bending zoom optical system of the present invention, at least in order from the object side, the first lens group having a negative refractive power, the second lens group having a positive refractive power, and at least one subsequent thereto. The zoom optical system includes at least one lens group that includes two lens groups and that moves along the optical axis when changing the magnification from the wide-angle end to the telephoto end. The lens group has a prism including at least one reflecting surface for bending an optical path, an entrance surface, and an exit surface, and at least one of the entrance surface and the exit surface of the prism is a curved surface. The refractive index nd at the d-line satisfies the following conditional expression (1).

1.6 <nd <2.0 (1) Hereinafter, the reason and action for adopting the above-mentioned configuration in the present invention will be described.

At least, in order from the object side, a first lens group, a second lens group, and at least one lens group after that, when zooming from the wide-angle end to the telephoto end,
In a zoom lens that includes the second lens group and moves along the optical axis, if the refractive power of the first lens group is negative, the height of light rays after the second lens group can be kept low, and the optical system thickness can be reduced. Can be thinned. Therefore, in the zoom optical system of the present invention, the first lens group has a negative refractive power, and the second lens group has a positive refractive power accordingly.

In order to direct the lens entrance surface toward the object side and reduce the depth, it is preferable to bend the optical path at a position on the object side of the optical system as much as possible. When the lens entrance surface is directed to the object side, the depth direction of the optical system is from the lens entrance surface to the optical path bending position. Therefore, if the prism that bends the optical path is located on the object side as much as possible, that is, in the first lens group, The depth direction can be made thinner.

When the optical path is bent by the prism, the light passes through the medium having a refractive index larger than 1, so that the air-equivalent length becomes longer even when the optical path is bent, as compared with the case where the mirror is used for bending the optical path. . Therefore, when the optical path is bent by the prism, the total length of the optical system can be shortened, and the optical system can be further downsized.

If at least one of the incident surface and the reflecting surface of the prism is a curved surface, for example, a curved surface that is rotationally symmetric with respect to the optical axis, the prism itself can have a refractive power, so that the number of lenses other than the prism can be reduced. The optical system can be made smaller by reducing the number. Further, it is possible to reduce the aberration by making the number of lenses the same.

If the refractive power of the prism is negative,
The light ray height on the image side of the prism can be lowered, and the thickness of the optical system can be made thinner. Further, if the refractive power of the prism is negative, the refractive power of the first lens group having negative refractive power including it can be shared, so that the number of constituent lenses of the first lens group can be reduced and the optical system can be downsized.

When the refractive index nd of the prism exceeds the lower limit of 1.6 of the conditional expression (1), the refractive power of the prism becomes small, so that the aberration can be corrected effectively and the ray height after the prism can be increased. It will not be possible to keep it low. The refractive power can be increased by increasing the curvature of the incident surface or the exit surface of the prism, but the larger the curvature, the greater the decentering sensitivity of the prism, and the performance tends to deteriorate. If the upper limit of 2.0 in conditional expression (1) is exceeded,
The dispersion of the medium becomes large and the chromatic aberration becomes large.

In the above, it is desirable to satisfy the following conditional expression (2).

−5.0 <f _1G / √ (f _w × f _t ) <− 0.3 (2) where f _1G is the focal length of the first lens group and f _w is the wide-angle end. The focal length of the entire system when focusing on an object point at infinity, and f _t is the focal length of the entire system when focusing on an object point at infinity at the telephoto end.

[0020] Conditional expression (2) _{further, -2.5 <f 1G / √ (} f w × f t) <- it is desirable to satisfy the 0.5 (2-1).

_{Furthermore, -1.7 <f 1G / √ (} f w × f t) <- it is more desirable to satisfy the 0.8 (2-2).

In order to make the optical system thin while suppressing the decentering sensitivity of the first lens group and the second lens group and thereafter, it is preferable to satisfy the conditional expression (2). Of the upper limit of conditional expression (2) −
If it exceeds 0.3, the refracting power of the first lens group becomes too small, the ray height after the second lens group becomes high, and the decentering sensitivity after the second lens group becomes high. In addition, the optical system becomes thick. When the lower limit of −5.0 to condition (2) is exceeded, the refractive power of the first lens group becomes too large, and the decentering sensitivity of the first lens group becomes high.

Further, if the conditional expression (2-1) is satisfied, the optical system can be made thinner while suppressing the decentering sensitivity after the first lens group and the second lens group to a lower level, which is more preferable.

Further, if the conditional expression (2-2) is satisfied, the optical system can be made thinner while the decentering sensitivity of the first lens group and the second lens group and thereafter can be further reduced, which is more preferable.

In addition, a third lens group having a positive refractive power is included after the second lens group, and when zooming from the wide-angle end to the telephoto end, the second lens group and the third lens group have a relative distance. It is desirable to move along the optical axis while changing.

That is, when zooming from the wide-angle end to the telephoto end, the second lens group having a positive refractive power and the third lens group having a positive refractive power move while changing the relative distance. With this method, it is possible to use a space efficiently and to obtain a high zoom ratio while performing focus position correction by zooming.

In this case, if the moving amounts of the second lens group and the third lens group when zooming from the wide-angle end to the telephoto end during focusing at infinity are M ₂ and M ₃ , the following conditional expression is obtained. It is desirable to satisfy (3).

0.3 <M ₃ / M ₂ <3.0 (3) Conditional expression (3) further includes 0.5 <M ₃ / M ₂ <2.0 (3-1 ) Is desirable.

Further, it is more preferable that the following condition is satisfied: 0.7 <M ₃ / M ₂ <1.7 (3-2).

When the ratio M ₃ / M ₂ of the moving amounts of the second lens group and the third lens group exceeds 3.0, which is the upper limit of the conditional expression (3), the third lens group moves very much. Therefore, at the telephoto end, the distance between the second lens group and the third lens group becomes too narrow, so that a space for the third lens group to focus can not be secured, and a sufficient focusable distance range cannot be secured. Further, if the focusable distance range is secured, the zoom ratio cannot be secured sufficiently. M ₃ / M
_{When the value of 2} exceeds the lower limit of 0.3 of the conditional expression (3), the third lens group does not move much, and it becomes impossible to secure a sufficient zoom ratio. Therefore, it is desirable that M ₃ / M ₂ satisfy the conditional expression (3).

It is more preferable to satisfy the conditional expression (3-1), because the zoom ratio and the focusable distance range can be secured more.

Further, if the conditional expression (3-2) is satisfied, the zoom ratio and the focusable distance range can be further secured, which is more preferable.

It is desirable that the magnification β _Rt of the combined system after the second lens group at the telephoto end satisfies the following conditional expression (4).

1.0 <−β _Rt <2.3 (4) Conditional expression (4) further satisfies 1.0 <−β _Rt <2.1 (4−1) Is desirable.

Further, it is more desirable that 1.0 <-β _Rt <1.9 (4-2) is satisfied.

In order to keep the relative distance change between the second lens group and the third lens group as small as possible, the absolute value of the magnification of the compound system after the second lens group is larger than 1 times and as close as possible to 1 times. It is better to change the magnification. That is, it is desirable to satisfy conditional expression (4), where β _Rt is the combined magnification when focusing on an object point at infinity at the telephoto end after the second lens group.
When the upper limit of 2.3 or the lower limit of 1.0 of the conditional expression (4) is exceeded, the amount of change in the relative distance between the second lens group and the third lens group becomes large.

Further, if the conditional expression (4-1) is satisfied, the change in the relative distance between the second lens group and the third lens group can be kept small.

If conditional expression (4-2) is satisfied, the second condition is satisfied.
It is possible to keep the relative distance change between the lens group and the third lens group small.

Further, in the optical path bending zoom optical system of the present invention, at least one aspherical surface is provided in the lens unit closest to the image side.
It is desirable to have a face.

In the lens group closest to the image side, the maximum ray height is high. Therefore, by disposing at least one aspherical surface in this most image-side lens group, it is possible to effectively correct off-axis aberrations such as distortion, astigmatism, and coma.

In this case, it is desirable that the lens unit closest to the image side be fixed during zooming and focusing.

The lens group closest to the image side has an aspherical surface, and aberrations generated on the object side relative to this aspherical surface, particularly off-axis aberrations, are canceled, and zooming or focusing causes the lens to move to the most image side in the optical axis direction. If you move the lens group in, the aberration balance will be lost. Therefore, it is better to fix the lens unit closest to the image side.

In this case, it is desirable that the second lens unit from the image side be moved in the optical axis direction to focus.

Focusing using the second lens group from the image side makes it possible to carry out focusing without degrading the performance, since there is little variation in focal length and aberration due to focusing.

In the optical path bending zoom optical system of the present invention, it is desirable that the first lens group have at least one aspherical surface.

In the first lens group, the ray height is high, and off-axis aberration cannot be suppressed if it is composed of only spherical surfaces. By disposing at least one aspherical surface in the first lens group, off-axis aberrations can be effectively corrected.

In this case, it is desirable that the first lens group be fixed during zooming and focusing.

The first lens group has an aspherical surface, and cancels aberrations generated on the object side of the aspherical surface, particularly off-axis aberrations. When moved in the optical axis direction by zooming or focusing, the aberration balance is achieved. Will be destroyed. Therefore, the first
The lens group should be fixed.

Further, in the optical path bending zoom optical system of the present invention, the lens group disposed on the image side of the prism or a part of the lens group disposed on the image side of the prism is moved in the optical axis direction. It is desirable to focus by doing so.

Since the prism is a bending system, the mechanism becomes complicated when it is moved in the optical axis direction by zooming or focusing. Further, when the lens group on the object side of the prism or a part of the lenses in the lens group is moved, the thickness of the optical system changes, which makes it difficult to reduce the thickness. Therefore, it is preferable to move and focus the lens group disposed on the image side of the prism or a part of the lenses in the lens group.

When the second lens group from the image side is moved in the optical axis direction for focusing, the infinity object point at the telephoto end of the second lens group and the third lens group from the image side is adjusted. It is desirable that the air distance DFT on the optical axis at the time of focusing satisfy the following conditional expression (5).

0.01 <DFT / f _t <2.0
(5) However, f _t is the focal length of the entire system when focusing on an object point at infinity at the telephoto end.

It is desirable that the conditional expression (5) further satisfies 0.03 <DFT / _ft <1.5 (5-1).

Furthermore, it is more desirable to satisfy 0.05 <DFT / f _t <1.0 (5-2).

When the focus position is changed to a closer distance side from the time of focusing on an object point at infinity at the telephoto end, the second lens group from the image side for focusing is extended to the object side. At this time, if the optical distance DFT on the optical axis between the second lens unit and the third lens unit from the image side is too small, that is, if the lower limit value of 0.01 of the conditional expression (5) is exceeded, the object is focused. The space that can be extended to the side becomes narrower, and it becomes impossible to achieve a sufficient focusable distance range. on the other hand,
When the upper limit of 2.0 to condition (5) is exceeded, the distance between the second and third lens units from the image side cannot be reduced during zooming, making it difficult to secure a zoom ratio. Therefore, the DFT should satisfy the conditional expression (5).

If the conditional expression (5-1) is satisfied, a more focusable distance range and a zoom ratio can be secured, which is more preferable.

Further, if the conditional expression (5-2) is satisfied, a more focusable distance range and a zoom ratio can be secured, which is more preferable.

When the third lens group having a positive refractive power is included, the first lens group includes one prism having a negative refractive power, one negative lens, and one positive lens. Therefore, it is desirable that the third lens group be composed of one positive lens.

Since the first lens group includes one prism having a negative refractive power and one negative lens, the prism,
It is possible to increase the refractive power of the entire first lens group without increasing the refractive power of the lens. Further, when the first lens group has a negative refracting power and the negative refracting power becomes large, the maximum ray height after the second lens group can be suppressed low, the size of the lens can be made small, and the optical system Can be made thinner. Further, it is possible to suppress the decentering sensitivity after the second lens group to be low.

When the third lens group having a positive refractive power is included, the first lens group is composed of one prism having a negative refractive power and one positive lens, and the third lens group is It is desirable to have one positive lens and one negative lens.

Since the first lens group consists of one prism having a negative refractive power and one positive lens, it is possible to reduce the number of lenses having a large maximum ray height and a large lens size.
This leads to weight reduction of the entire optical system. Further, since the third lens group consists of one positive lens and one negative lens,
It is possible to increase the refractive power of the entire third lens group without increasing the refractive power of each lens. Therefore, the third
The amount of movement of the lens group during zooming and focusing can be suppressed to a small amount, and the zoom ratio and the focusable distance range can be more sufficiently taken.

In the above, it is desirable to focus by moving the third lens group in the optical axis direction.

The third lens group consists of one positive lens, or one positive lens and one negative lens, and the third lens group has a small number of lenses and a light weight. Therefore, if the third lens group is moved and focused, the power consumption required for the movement can be reduced.

In the above, when the first lens group has an aspherical surface, at least one of the entrance surface and the exit surface of the prism may be an aspherical surface.

If the prism has a high ray height and at least one of the entrance surface and the exit surface is an aspherical surface, off-axis aberrations such as distortion, astigmatism, and coma can be effectively corrected.

In the above, when the first lens group or the lens group closest to the image side has an aspherical surface, the lens or prism on which the aspherical surface is formed is made of glass, and its transition point Tg has the following conditional expression (6). It is desirable to satisfy.

60 ° C. <Tg <620 ° C. (6) The aspherical shape cannot be accurately formed by polishing, and it is difficult to process a large amount by grinding.
When the lens or prism having the aspherical surface is made of glass that satisfies the conditional expression (6), it can be processed by the glass molding method and can be easily mass-produced. Therefore, the optical system becomes inexpensive.

When the first lens group or the lens group closest to the image side has an aspherical surface, it is desirable that the lens or prism having the aspherical surface be processed by a glass molding method.

The aspherical shape cannot be accurately formed by polishing, and it is difficult to process a large amount by grinding. If a lens or prism having an aspherical surface is processed by a glass molding method, it can be easily mass-produced and the optical system becomes inexpensive.

When the first lens group or the lens group closest to the image side has an aspherical surface, the lens or prism having the aspherical surface can be made of an organic-inorganic hybrid material.

The organic-inorganic hybrid material is, for example, as described in JP-A-7-90181, one in which an organic material is dispersed in an inorganic material, or one in which an inorganic material is dispersed. Since it has a lower melting point than glass, it can be molded at a low temperature and easily mass-produced, and the optical system becomes inexpensive. Further, as compared with plastic, high refractive index and low dispersion optical characteristics are obtained, and heat resistance is excellent. Further, it is not easily scratched and can be used, for example, as a front lens of an optical system. Therefore, it is desirable to use such an organic-inorganic hybrid material for a lens or prism having at least an aspherical surface.

When the first lens group or the lens group closest to the image side has an aspherical surface, the lens or prism on which the aspherical surface is formed can be made of plastic.

When the prism is made of plastic, a large amount of prisms or lenses having an aspherical surface can be easily produced by a plastic molding method. Moreover, since the material cost is low, an inexpensive prism and an inexpensive optical system can be obtained. Also, because plastic is lighter than glass, the weight of the optical system can be reduced.

In the optical path bending zoom optical system of the present invention, the prism can be made of plastic.

The prism has a larger volume than other lenses, and if the prism is made of light plastic, it is particularly effective in reducing the weight. Further, it can be produced by a plastic molding method, and can be easily produced in a large amount. Furthermore, since the material cost is low, an inexpensive optical system can be obtained.

Further, in the optical path bending zoom optical system of the present invention, all lenses and prisms can be made of plastic.

When all the lenses and the prisms are made of plastic, all the lenses and the prisms can be produced by the plastic molding method and can be easily produced in a large amount. Moreover, since the material cost is low, an inexpensive optical system can be obtained.

Further, in the optical path bending zoom optical system of the present invention, it is desirable that the optical axis is bent so that the bending surface of the optical axis is parallel to the short side of the image pickup surface of the image pickup device arranged on the image plane. .

If the optical axis is bent in the direction of the short side of, for example, the CCD arranged on the image plane, the outermost position on the CCD in the bending direction becomes lower than in the case of bending in the direction of the long side. Therefore, the size of the reflecting surface can be reduced, the thickness of the prism can be reduced, and the optical system can be made thinner.

Further, in the optical path bending zoom optical system of the present invention, it is preferable that the prism is arranged closer to the object side than the most object side lens of all the lens groups that are movable during zooming.

That is, in order not to complicate the zoom or focus drive system, it is preferable that the moving group is closer to the image side than the bending position.

In the optical path bending zoom optical system of the present invention, the lens group that moves during zooming can move monotonously toward the object side when zooming from the wide-angle end to the telephoto end.

If the lens unit that moves during zooming is monotonically moved to the object side, the mechanism for movement becomes simple.

In the optical path bending zoom optical system of the present invention, it is desirable to dispose at least one aperture stop on the optical path on the image side of the prism.

When the aperture stop is provided on the object side of the prism, the optical path length on the object side of the prism becomes long and the optical system becomes thick.

When the third lens group having a positive refracting power is included, the third lens group can be moved in the optical axis direction for focusing.

The third lens group moves during zooming, and
When focusing with the lens group, the moving mechanism for zooming can be used even during focusing, the mechanism is simple, and the entire optical system including the mechanism can be made compact and lightweight.

Further, the zoom optical system of the present invention as described above, the electronic image pickup device arranged at a position for receiving the object image formed by the zoom optical system, and the electron photoelectrically converted by the electronic image pickup device. A processing means for processing a signal, an input section for an operator to input an information signal desired to be input to the processing means, a display element for displaying an output from the processing means, and an output from the processing means are recorded. An information processing apparatus including a recording medium, the processing means of which is configured to display an object image received by an electronic image pickup element by a zoom optical system on a display element, can be configured based on the present invention. .

In this case, according to the present invention, a personal computer device is constructed based on the present invention, the input unit of which is composed of a keyboard, and the zoom optical system and the electronic image pickup device are built in the peripheral portion of the display element or the peripheral portion of the keyboard. can do.

Further, the zoom optical system of the present invention as described above, the electronic image pickup device arranged at a position for receiving the object image formed by the zoom optical system, and the antenna for transmitting and receiving telephone signals. Based on the present invention, there is provided a telephone device including an input unit for inputting a signal such as a telephone number, and a signal processing unit for converting an object image received by the electronic image pickup device into a transmittable signal. Can be configured.

Further, the zoom optical system of the present invention as described above, the electronic image pickup device arranged at the position for receiving the object image formed by the zoom optical system, and the electron photoelectrically converted by the electronic image pickup device A recording member having a processing means for processing a signal and a display element for observably displaying an object image received by the electronic image sensor, and recording image information of the object image received by the electronic image sensor. And a processing function for displaying the object image received by the electronic image pickup device on the display device, and recording the object image received by the electronic image pickup device on the recording medium. An electronic camera device having a recording processing function for performing the above can be configured based on the present invention.

With this configuration, the digital camera itself can be made thin. Further, even if a mobile terminal such as a mobile personal computer or a mobile phone is equipped with an image pickup function, it is not necessary to increase the size of the mobile terminal.

[0093]

BEST MODE FOR CARRYING OUT THE INVENTION Examples 1 to 10 of the optical path bending zoom optical system of the present invention will be described below. FIG. 1 shows lens cross-sectional views at the wide-angle end (a), the intermediate state (b), and the telephoto end (c) when focusing on an object point at infinity in each of these examples.
~ Shown in FIG. In each drawing, the first lens group is G1, the second lens group is G2, the third lens group is G3, and the fourth lens group is G.
4. Optical path bending prism is P, aperture stop is S, near-infrared cut filter, low-pass filter, parallel plane plate group such as cover glass of CCD which is an electronic image pickup device is F, C
The image plane of the CD is indicated by I, and the plane-parallel plate group F is fixedly arranged between the final lens group and the image plane I.

The optical path bending zoom optical system of Example 1 is
As shown in FIG. 1, an optical path bending prism P equivalent to a biconcave negative lens, a negative meniscus lens convex on the image side, and a biconvex positive lens, a first lens group G1, an aperture stop S,
A second lens group G2 including two biconvex positive lenses and a negative meniscus lens convex toward the object side, a third lens group G3 including one biconvex positive lens, and a fourth lens group including one biconvex positive lens.
When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the aperture stop S and the second lens group G2 move integrally to the object side, and the third lens group G3 is formed. Moves to the object side while narrowing the gap with the second lens group G2 and then narrowing it, and the fourth lens group G4 is fixed.

The aspherical surfaces are the entrance surface of the optical path bending prism P of the first lens group G1, the object side surface of the negative meniscus lens, the most object side surface of the second lens group G2, and the object side surface of the fourth lens group G4. It is used on the four sides of the.

In this embodiment, the optical path bending prism P is made of plastic.

The optical path bending zoom optical system of Example 2 is
As shown in FIG. 2, an optical path bending prism P equivalent to a biconcave negative lens, a negative meniscus lens convex on the image plane side, and a biconvex positive lens, a first lens group G1, an aperture stop S,
A second lens group G2 consisting of two biconvex positive lenses and a negative meniscus lens convex to the object side, a third lens group G3 consisting of one positive meniscus lens convex to the object side, and a biconvex positive lens When the magnification is changed from the wide-angle end to the telephoto end, the first lens group G1 is fixed, and the aperture stop S and the second lens group G2 move integrally to the object side.
The third lens group G3 moves toward the object side while narrowing the gap between the third lens group G3 and the second lens group G2 and then narrowing the gap.
4 is fixed.

The aspherical surfaces are the incident surface of the optical path bending prism P of the first lens group G1, the object side surface of the negative meniscus lens, the most object side surface of the second lens group G2, and the object side surface of the fourth lens group G4. It is used on the four sides of the.

In this embodiment, the optical path bending prism P is made of plastic.

The optical path bending zoom optical system of Example 3 is
As shown in FIG. 3, a first lens group G1 including an optical path bending prism P equivalent to a negative meniscus lens convex to the object side, a biconcave negative lens, and a positive meniscus lens convex to the object side, an aperture stop S. A second lens group G2 consisting of two biconvex positive lenses and a negative meniscus lens convex to the object side, a third lens group G3 consisting of one biconvex positive lens, and a positive meniscus lens convex to the image side. It consists of a single fourth lens group G4. When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the aperture stop S moves toward the object side, and the second lens group G2 opens. The third lens group G3 moves toward the object side while narrowing the distance from the diaphragm S, and the third lens group G3 moves toward the object side while narrowing the distance from the second lens group G2, and the fourth lens group G4 is fixed. is there.

The aspherical surfaces are the object-side surface of the biconcave negative lens of the first lens group G1, the object-side surface of the positive meniscus lens, the most object-side surface of the second lens group G2, and the fourth lens group G4. It is used for four surfaces on the object side.

In this embodiment, all the elements including the optical path bending prism P are made of glass.

The optical path bending zoom optical system of Example 4 is as follows:
As shown in FIG. 4, a first lens group G including an optical path bending prism P equivalent to a biconcave negative lens and a biconvex positive lens.
1. A second lens group G2 including an aperture stop S, a biconvex positive lens, a positive meniscus lens convex to the object side, and a negative meniscus lens convex to the object side, a positive meniscus lens convex to the object side, and an object The third lens group G3 is composed of a negative meniscus lens having a convex surface on the side, and the fourth lens group G4 is composed of one positive meniscus lens having a convex surface on the object side. When zooming from the wide-angle end to the telephoto end, The lens group G1 is fixed, the aperture stop S moves to the object side, the second lens group G2 moves to the object side while narrowing the interval with the aperture stop S, and the third lens group G3.
Moves to the object side while narrowing the gap with the second lens group G2 and then narrowing it, and the fourth lens group G4 is fixed.

The aspherical surfaces are the incident surface of the optical path bending prism P of the first lens group G1, the object-side surface of the biconvex positive lens, the most object-side surface of the second lens group G2, and the object of the fourth lens group G4. It is used on the four side surfaces.

In this embodiment, all the elements including the optical path bending prism P are made of glass.

The optical path bending zoom optical system of Example 5 is as follows:
As shown in FIG. 5, a first lens group G including an optical path bending prism P equivalent to a biconcave negative lens and a biconvex positive lens.
1. A second lens group G2 including an aperture stop S, a biconvex positive lens, a positive meniscus lens having a convex surface on the object side, and a negative meniscus lens having a convex surface on the object side, a biconvex positive lens, and a convex surface on the image side. The third lens group G3 including a negative meniscus lens and the fourth lens group G4 including one positive meniscus lens having a convex surface on the object side. The first lens group G1 is used when zooming from the wide-angle end to the telephoto end. Is fixed, the aperture stop S moves to the object side, the second lens group G2 moves to the object side while narrowing the interval with the aperture stop S, and the third lens group G3 moves to the second lens group G3.
The fourth lens group G4 is fixed while moving toward the object side while widening the distance from 2.

The aspherical surface is the object-side surface of the biconvex positive lens of the first lens group G1, the most object-side surface of the second lens group G2,
It is used for the three object-side surfaces of the fourth lens group G4.

In this embodiment, all the elements including the optical path bending prism P are made of glass.

The optical path bending zoom optical system of the sixth embodiment is
As shown in FIG. 6, an optical path bending prism P equivalent to a biconcave negative lens, a first lens group G1 including a positive meniscus lens having a convex surface on the object side, an aperture stop S, and a biconvex positive lens,
A second lens group G2 including a positive meniscus lens convex on the object side and a negative meniscus lens convex on the object side, and a third lens group G including one positive meniscus lens convex on the object side.
3. The fourth lens group G4 is composed of one biconvex positive lens, and when changing the magnification from the wide-angle end to the telephoto end,
1 is fixed, the aperture stop S moves to the object side, the second lens group G2 moves to the object side while narrowing the interval with the aperture stop S and then widening, and the third lens group G3 moves to the second lens group G3. The fourth lens group G4 is fixed while the distance from the group G2 is once widened and then moved toward the object side while being narrowed.

The aspherical surfaces are the incident surface of the optical path bending prism P of the first lens group G1, the object side surface of the positive meniscus lens, the most object side surface of the second lens group G2, and the object side surface of the fourth lens group G4. It is used on the four sides of the.

In this embodiment, the optical path bending prism P is made of plastic.

The optical path bending zoom optical system of Example 7 is as follows:
As shown in FIG. 7, a first lens group G including an optical path bending prism P equivalent to a biconcave negative lens and a biconvex positive lens.
1, an aperture stop S, a second lens group G2 including two biconvex positive lenses, and a biconcave negative lens, a biconvex positive lens, and a third lens group including a negative meniscus lens convex on the image side. G
3, 4th consisting of one positive meniscus lens convex on the object side
When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the aperture stop S moves toward the object side, and the second lens group G2 sets the distance from the aperture stop S to the object side. The third lens group G3 moves toward the object side while narrowing, the gap between the third lens group G3 and the second lens group G2 is once widened, and then moves toward the object side while narrowing, and the fourth lens group G4 is fixed.

The aspherical surface is the object-side surface of the biconvex positive lens of the first lens group G1, the most object-side surface of the second lens group G2,
It is used for the three object-side surfaces of the fourth lens group G4.

In this embodiment, the three lenses of the second lens group G2 are made of plastic.

The optical path bending zoom optical system of Example 8 is as follows:
As shown in FIG. 8, an optical path bending prism P equivalent to a biconcave negative lens, a first lens group G1 including a positive meniscus lens convex on the object side, an aperture stop S, and two biconvex positive lenses, A second lens group G2 including a biconcave negative lens, a third lens group G including a biconvex positive lens, and a biconcave negative lens
3, 4th consisting of one positive meniscus lens convex on the object side
When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the aperture stop S moves toward the object side, and the second lens group G2 sets the distance from the aperture stop S to the object side. The third lens group G3 moves toward the object side while narrowing, the gap between the third lens group G3 and the second lens group G2 is once widened, and then moves toward the object side while narrowing, and the fourth lens group G4 is fixed.

The aspherical surface is the entrance surface of the optical path bending prism P of the first lens group G1, the object side surface of the positive meniscus lens, the object side surface of the second lens group G2, and the object side of the third lens group G3. Side surface and five surfaces of the object side surface of the fourth lens group G4.

In this embodiment, all the lenses and prisms in the first lens group G1 to the fourth lens group G4 are made of plastic.

The optical path bending zoom optical system of the ninth embodiment is
As shown in FIG. 9, a first lens group G1 including an optical path bending prism P equivalent to a biconcave negative lens, a biconcave negative lens, and a biconvex positive lens, an aperture stop S, and two biconvex positive lenses. And a second lens group G2 including a negative meniscus lens convex toward the object side, a third lens group G3 including one positive meniscus lens facing toward the object side, and a fourth lens group G1 including one biconvex positive lens.
When the magnification is changed from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, and the first lens group G1 and the second lens group G2 are formed. The aperture stop S between is narrowing the interval with the second lens group G2 from the wide-angle end to the intermediate state, and moves integrally with the second lens group G2 from the intermediate state to the telephoto end, and the third lens group G3 is moved toward the object side while widening the gap with the second lens group G2 and then narrowing it, and the fourth lens group G4 is fixed.

The aspherical surfaces are the incident surface of the optical path bending prism P of the first lens group G1, the object-side surface of the biconcave negative lens, the most object-side surface of the second lens group G2, and the object of the fourth lens group G4. It is used on the four side surfaces.

In this embodiment, the optical path bending prism P is made of plastic.

As shown in FIG. 10, the optical path bending zoom optical system of the tenth embodiment has a first lens composed of an optical path bending prism P equivalent to a biconcave negative lens, a biconcave negative lens and a biconvex positive lens. A second lens group G2 including a group G1, an aperture stop S, two biconvex positive lenses, and a negative meniscus lens convex on the object side, and a positive meniscus lens 1 convex on the object side.
It consists of a third lens group G3 consisting of one lens element and a fourth lens group G4 consisting of one biconvex positive lens element. When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed and the aperture stop S is The second lens group G2 moves toward the object side while narrowing the distance from the aperture stop S, and moves toward the object side, and the third lens group G3 moves toward the second lens group G3.
The fourth lens group G4 is fixed while the distance from the lens group G2 is once widened and then moved toward the object side while being narrowed.

The aspherical surfaces are the incident surface of the optical path bending prism P of the first lens group G1, the object-side surface of the biconcave negative lens, the most object-side surface of the second lens group G2, and the object of the fourth lens group G4. It is used on the four side surfaces.

In this embodiment, the optical path bending prism P is made of plastic.

In each of Examples 1 to 10 described above, the first lens group G1 has a negative refractive power and the second lens group G has a negative refractive power.
2, the third lens group G3 and the fourth lens group G4 have positive refracting power, and the third lens group G3 is extended to the object side to focus on a short-distance object.

Numerical data of each of the above-mentioned embodiments will be shown below. Symbols are other than the above, f is the focal length of the entire system, 2ω is the angle of view,
F _NO is the F number, WE is the wide-angle end, ST is the intermediate state, T
E is the telephoto end, r ₁ , r ₂ ... Is the radius of curvature of each lens surface, d
₁ , d ₂ ... Intervals between lens surfaces, n _d1 , n _d2 ..., Refractive index of d line of each lens, ν _d1 , ν _d2, ... Abbe number of each lens. Further, “RE” indicates a reflecting surface. The aspherical shape is represented by the following formula, where x is an optical axis with the traveling direction of light being positive and y is a direction orthogonal to the optical axis.

X = (y ² / r) / [1+ {1- (K +
1) (y / r) ² } ^1/2 ] + A ₄ y ⁴ + A ₆ y ⁶ + A ₈ y ⁸ +
A ₁₀ y ¹⁰ However, r is a paraxial radius of curvature, K is a conic coefficient, A ₄ , A ₆ ,
A ₈ and A ₁₀ are aspherical coefficients of the 4th, 6th, 8th and 10th orders, respectively.

Example 1 r ₁ = -17.3764 (aspherical surface) d ₁ = 3.2840 n _d1 = 1.52540 ν _d1 = 56.25 r ₂ = ∞ (RE) d ₂ = 4.4140 n _d2 = 1.52540 ν _d2 = 56.25 r ₃ = 6.9338 d ₃ = 2.0562 r ₄ = -5.7193 (aspherical surface) d ₄ = 0.6000 n _d3 = 1.58913 ν _d3 = 61.14 r ₅ = -16.8060 d ₅ = 0.1089 r ₆ = 42.1844 d ₆ = 1.2031 n _d4 = 1.84666 ν _d4 = 23.78 r ₇ = -23.2853 d ₇ = (variable) r ₈ = ∞ (aperture) d ₈ = 0.9998 r ₉ = 10.8298 (aspherical surface) d ₉ = 1.6521 n _d5 = 1.48749 ν _d5 = 70.23 r ₁₀ = -15.4299 d ₁₀ = 0.1148 r ₁₁ = 8.3013 d ₁₁ = 1.9637 n _d6 = 1.48749 ν _d6 = 70.23 r ₁₂ = -46.5864 d ₁₂ = 0.3474 r ₁₃ = 24.9162 d ₁₃ = 2.8699 n _d7 = 1.84666 ν _d7 = 23.78 r ₁₄ = 5.3115 d ₁₄ = ( Variable) r ₁₅ = 11.2652 d ₁₅ = 1.4981 n _d8 = 1.48749 ν _d8 = 70.23 r ₁₆ = -179.3191 d ₁₆ = (variable) r ₁₇ = 26.6599 (aspherical surface) d ₁₇ = 1.3970 n _d9 = 1.48749 ν _d9 = 70.23 r ₁₈ = -19.7457 d ₁₈ = 0.6066 r ₁₉ = ∞ d ₁₉ = 0.8000 n _d10 = 1.51633 ν _d10 = 64.14 r ₂₀ = ∞ d ₂₀ = 1.8000 n _d11 = 1.54771 ν _d11 = 62.84 r ₂₁ = ∞ d ₂₁ = 0.5000 r ₂₂ = ∞ d ₂₂ = 0.5000 n _d12 = 1.51633 ν _d12 = 64.14 r ₂₃ = ∞ d ₂₃ = 1.2117 r ₂₄ = ∞ (image plane) Aspherical coefficient 1st surface K = 0 A ₄ = 4.5818 × 10 ^-4 A ₆ = -4.6789 × 10 ^-6 A ₈ = 6.9273 × 10 ^-8 A ₁₀ = -4.3726 × 10 ^-10 4th surface K = 0 A ₄ = -2.8145 × 10 ^-4 A ₆ = 1.5591 × 10 ^-6 A ₈ = -3.6111 × 10 ^-6 A ₁₀ = 1.4914 × 10 ^-7 9th surface K = 0 A ₄ = -4.3262 × 10 ^-4 A ₆ = -1.1293 × 10 ^-6 A ₈ = 4.8515 × 10 ^-7 A ₁₀ = -2.8317 × 10 ^-8 17th surface K = 0 A ₄ = -5.5147 × 10 ^-4 A ₆ = 2.6573 × 10 ^-6 A ₈ = -2.2587 × 10 ^-7 A ₁₀ = -7.7929 × 10 ^-9 Zoom data (∞) WE ST TE f (mm) 4.624 7.795 13.319 F _NO 2.800 3.497 4.579 2ω ( °) 65.06 39.74 23.18 d ₇ 11.7219 5.3659 0.9994 d ₁₄ 5.3163 7.0392 1.4070 d ₁₆ 0.3378 4.9904 14.9874.

Example 2 r ₁ = -16.2703 (aspherical surface) d ₁ = 3.3160 n _d1 = 1.52540 ν _d1 = 56.25 r ₂ = ∞ (RE) d ₂ = 4.3120 n _d2 = 1.52540 ν _d2 = 56.25 r ₃ = 6.2340 d ₃ = 1.8658 r ₄ = -8.0126 (aspherical surface) d ₄ = 0.6000 n _d3 = 1.58913 ν _d3 = 61.14 r ₅ = -87.5224 d ₅ = 0.0970 r ₆ = 17.7033 d ₆ = 1.2354 n _d4 = 1.84666 ν _d4 = 23.78 r ₇ = -57.3681 d ₇ = (variable) r ₈ = ∞ (aperture) d ₈ = 0.9976 r ₉ = 9.8247 (aspherical surface) d ₉ = 1.6026 n _d5 = 1.48749 ν _d5 = 70.23 r ₁₀ = -22.2883 d ₁₀ = 0.0972 r ₁₁ = 6.8874 d ₁₁ = 2.0574 n _d6 = 1.48749 ν _d6 = 70.23 r ₁₂ = -49.1281 d ₁₂ = 0.3490 r ₁₃ = 12.1835 d ₁₃ = 1.0043 n _d7 = 1.84666 ν _d7 = 23.78 r ₁₄ = 4.7572 d ₁₄ = ( Variable) r ₁₅ = 11.5898 d ₁₅ = 1.4123 n _d8 = 1.48749 ν _d8 = 70.23 r ₁₆ = 82.0834 d ₁₆ = (variable) r ₁₇ = 18.9013 (aspherical surface) d ₁₇ = 1.3793 n _d9 = 1.48749 ν _d9 = 70.23 r ₁₈ = -37.9025 d ₁₈ = 0.6834 r ₁₉ = ∞ d ₁₉ = 0.8000 n _{d1 0} = 1.51633 ν _d10 = 64.14 r ₂₀ = ∞ d ₂₀ = 1.8000 n _d11 = 1.54771 ν _d11 = 62.84 r ₂₁ = ∞ d ₂₁ = 0.5000 r ₂₂ = ∞ d ₂₂ = 0.5000 n _d12 = 1.51633 ν _d12 = 64.14 r ₂₃ = ∞ d ₂₃ = 1.2115 r ₂₄ = ∞ (image plane) Aspheric coefficient 1st surface K = 0 A ₄ = 4.8235 × 10 ^-4 A ₆ = -5.1018 × 10 ^-6 A ₈ = 5.7666 × 10 ^-8 A ₁₀ = -2.9333 × 10 ^-10 4th surface K = 0 A ₄ = -3.3016 × 10 ^-4 A ₆ = -3.2719 × 10 ^-5 A ₈ = 2.5224 × 10 ^-6 A ₁₀ = -1.5352 × 10 ^-7 9th surface K = 0 A ₄ = -5.0596 × 10 ^-4 A ₆ = 3.0757 × 10 ^-6 A ₈ = -4.1244 × 10 ^-7 A ₁₀ = 8.2339 × 10 ^-9 17th surface K = 0 A ₄ = -4.7915 × 10 ^-4 A ₆ = -1.1388 × 10 ^-5 A ₈ = 8.5208 × 10 ^-7 A ₁₀ = -4.0916 × 10 ^-8 Zoom data (∞) WE ST TE f (mm) 4.620 7.769 13.318 F _NO 2.800 3.497 4.579 2ω ( °) 64.92 39.72 23.14 d ₇ 11.6223 5.3076 0.9969 d ₁₄ 7.5065 8.5876 1.4683 d ₁₆ 0.3508 5.6098 17.0450.

Example 3 r ₁ = 27.1044 d ₁ = 4.7220 n _d1 = 1.88300 ν _d1 = 40.76 r ₂ = ∞ (RE) d ₂ = 3.5955 n _d2 = 1.88300 ν _d2 = 40.76 r ₃ = 4.9756 d ₃ = 2.3010 r ₄ = -11.9474 (aspherical surface) d ₄ = 0.6000 n _d3 = 1.58913 ν _d3 = 61.14 r ₅ = 10.1822 d ₅ = 0.4447 r ₆ = 8.3844 (aspherical surface) d ₆ = 1.4272 nd _d = 1.84666 ν _d4 = 23.78 r ₇ = 45.6667 d ₇ = (variable) r ₈ = ∞ (aperture) d ₈ = (variable) r ₉ = 10.7735 (aspherical surface) d ₉ = 1.8705 n _d5 = 1.48749 ν _d5 = 70.23 r ₁₀ = -14.9931 d ₁₀ = 0.5376 r ₁₁ = 7.0291 d ₁₁ = 2.0442 n _d6 = 1.48749 ν _d6 = 70.23 r ₁₂ = -29.1724 d ₁₂ = 0.2628 r ₁₃ = 12.3764 d ₁₃ = 0.7972 n _d7 = 1.84666 ν _d7 = 23.78 r ₁₄ = 4.9385 d ₁₄ = (variable ) R ₁₅ = 11.8118 d ₁₅ = 1.6243 n _d8 = 1.48749 ν _d8 = 70.23 r ₁₆ = -79.0013 d ₁₆ = (variable) r ₁₇ = -53.6897 (aspherical surface) d ₁₇ = 1.0807 n _d9 = 1.48749 ν _d9 = 70.23 r ₁₈ = -15.5557 d ₁₈ = 0.6894 r ₁₉ = ∞ d ₁₉ = 0.8000 n _d10 = 1.51633 ν _d10 = 64.14 r ₂₀ = ∞ d ₂₀ = 1.8000 n _d11 = 1.54771 ν _d11 = 62.84 r ₂₁ = ∞ d ₂₁ = 0.5000 r ₂₂ = ∞ d ₂₂ = 0.5000 n _d12 = 1.51633 ν _d12 = 64.14 r ₂₃ = ∞ d ₂₃ = 1.2104 r ₂₄ = ∞ (image plane) Aspheric coefficient 4th surface K = 0 A ₄ = 2.3501 × 10 ^-3 A ₆ = -6.3312 × 10 ^-5 A ₈ = -6.9724 × 10 ^-6 A ₁₀ = 5.7489 × 10 ^-7 6th surface K = 0 A ₄ = -1.1631 × 10 ^-3 A ₆ = 3.6007 × 10 ^-5 A ₈ = 4.4738 × 10 ^-6 A ₁₀ = -3.4837 × 10 ^-7 9th surface K = 0 A ₄ = -5.7035 × 10 ^-4 A ₆ = -5.4180 × 10 ^-6 A ₈ = 5.3938 × 10 ^-7 A ₁₀ = -4.2901 × 10 ^-8 17th surface K = 0 A ₄ = -8.5697 × 10 ^-4 A ₆ = 2.2449 × 10 ^-5 A ₈ = -2.4074 × 10 ^-6 A ₁₀ = 8.8890 × 10 ^-8 Zoom data (∞) WE ST TE f (mm) 4.623 7.950 13.702 F _NO 2.859 3.591 4.730 2ω ( °) 64.66 38.71 22.51 d ₇ 9.9386 4.4841 0.9991 d ₈ 1.7542 1.1944 0.8593 d ₁₄ 6.0738 7.2831 1.4976 d ₁₆ 0.8052 5.6280 15.2303.

Example 4 r ₁ = -16.4145 (aspherical surface) d ₁ = 3.5085 n _d1 = 1.80610 ν _d1 = 40.92 r ₂ = ∞ (RE) d ₂ = 3.5024 n _d2 = 1.80610 ν _d2 = 40.92 r ₃ = 6.1870 d ₃ = 1.2716 r ₄ = 13.0384 (aspherical surface) d ₄ = 1.8330 n _d3 = 1.80809 ν _d3 = 22.76 r ₅ = -71.4767 d ₅ = (variable) r ₆ = ∞ (aperture) d ₆ = (variable) r ₇ = 5.4233 (aspherical surface) d ₇ = 2.6870 n _d4 = 1.48749 ν _d4 = 70.23 r ₈ = -64.3346 d ₈ = 0.3381 r ₉ = 15.0638 d ₉ = 1.4457 n _d5 = 1.69680 ν _d5 = 55.53 r ₁₀ = 41.8538 d ₁₀ = 0.1990 r ₁₁ = 8.4846 d ₁₁ = 0.7950 n _d6 = 1.84666 ν _d6 = 23.78 r ₁₂ = 4.1084 d ₁₂ = (variable) r ₁₃ = 7.7486 d ₁₃ = 1.9936 n _d7 = 1.48749 ν _d7 = 70.23 r ₁₄ = 233.7602 d ₁₄ = 0.2849 r ₁₅ = 19.3480 d ₁₅ = 1.0023 n _d8 = 1.84666 ν _d8 = 23.78 r ₁₆ = 13.9416 d ₁₆ = (variable) r ₁₇ = 18.1663 (aspherical surface) d ₁₇ = 1.5276 n _d9 = 1.58913 ν _d9 = 61.26 r ₁₈ = _{541.6115 d 18 = 0.9655 r 19 =} ∞ d 19 = 0.8000 _{d10 = 1.51633 ν d10 = 64.14 r} 20 = ∞ d 20 = 1.8000 n d11 = 1.54771 ν d11 = 62.84 r 21 = ∞ d 21 = 0.5000 r 22 = ∞ d 22 = 0.5000 n d12 = 1.51633 ν d12 = 64.14 r 23 = ∞ d ₂₃ = 1.2298 r ₂₄ = ∞ (image plane) Aspheric surface first surface K = 0 A ₄ = 4.0309 × 10 ^-4 A ₆ = -4.7575 × 10 ^-6 A ₈ = 3.9047 × 10 ^-8 A ₁₀ = 0.0000 4th surface K = 0.983 8 A ₄ = 1.9404 × 10 ^-4 A ₆ = 5.6278 × 10 ^-6 A ₈ = 1.4359 × 10 ^-7 A ₁₀ = 0.0000 7th surface K = 0 A ₄ = -7.1014 × 10 ^-4 A ₆ = -1.1335 × 10 ^-5 A ₈ = -6.4501 × 10 ^-7 A ₁₀ = 0.0000 17th surface K = 0 A ₄ = -5.7585 × 10 ^-4 A ₆ = 4.3139 × 10 ^-6 A ₈ = -8.6426 × 10 ^-7 A ₁₀ = 0.0000 Zoom data (∞) WE ST TE f (mm) 4.678 7.851 13.217 F _NO 2.800 3.802 4.902 2ω (°) 64.15 39.67 23.31 d ₅ 11.9861 6.5855 1.2485 d ₆ 3.2686 1.3388 1.0643 d ₁₂ 2.9205 6.9804 4.6904 d ₁₆ 1.1429 4.4758 12.3755.

Example 5 r ₁ = -129.7294 d ₁ = 4.0499 n _d1 = 1.80400 ν _d1 = 46.57 r ₂ = ∞ (RE) d ₂ = 4.5020 n _d2 = 1.80400 ν _d2 = 46.57 r ₃ = 5.3898 d ₃ = 1.6465 r ₄ = 30.0332 (aspherical surface) d ₄ = 1.4609 n _d3 = 1.84666 ν _d3 = 23.78 r ₅ = -35.8611 d ₅ = (variable) r ₆ = ∞ (aperture) d ₆ = (variable) r ₇ = 9.6063 (non-spherical) Spherical surface) d ₇ = 2.7296 n _d4 = 1.48749 ν _d4 = 70.23 r ₈ = -30.8421 d ₈ = 0.1469 r ₉ = 10.1172 d ₉ = 2.1277 n _d5 = 1.69680 ν _d5 = 55.53 r ₁₀ = 97.1974 d ₁₀ = 0.0500 r ₁₁ = 12.1982 d ₁₁ = 0.7949 n _d6 = 1.84666 ν _d6 = 23.78 r ₁₂ = 5.7271 d ₁₂ = (variable) r ₁₃ = 14.2960 d ₁₃ = 4.0342 n _d7 = 1.48749 ν _d7 = 70.23 r ₁₄ = -15.7323 d ₁₄ = 0.1401 r ₁₅ = -18.5671 d ₁₅ = 1.1241 n _d8 = 1.84666 ν _d8 = 23.78 r ₁₆ = -29.8834 d ₁₆ = (variable) r ₁₇ = 46.3841 (aspherical) d ₁₇ = 1.1752 n _d9 = 1.58913 ν _d9 = 61.26 r ₁₈ = 541.6142 d ₁₈ = 0.4453 r ₁₉ = ∞ d ₁₉ = 0.8000 n _d10 = 1.5 1633 ν _d10 = 64.14 r ₂₀ = ∞ d ₂₀ = 1.8000 n _d11 = 1.54771 ν _d11 = 62.84 r ₂₁ = ∞ d ₂₁ = 0.5000 r ₂₂ = ∞ d ₂₂ = 0.5000 n _d12 = 1.51633 ν _d12 = 64.14 r ₂₃ = ∞ d ₂₃ = 1.2588 r ₂₄ = ∞ (Image plane) Aspheric coefficient 4th surface K = 42.6072 A ₄ = 4.5281 × 10 ^-4 A ₆ = -1.2752 × 10 ^-6 A ₈ = 2.9327 × 10 ^-7 A ₁₀ = 0.0000 7th surface K = 0 A ₄ = -2.9136 × 10 ^-4 A ₆ = -7.7511 × 10 ^-7 A ₈ = 2.4221 × 10 ^-8 A ₁₀ = 0.0000 17th surface K = 0 A ₄ = -8.0585 × 10 ^-4 A ₆ = 1.7583 × 10 ^-5 A ₈ = -1.1309 × 10 ^-6 A ₁₀ = 0.0000 Zoom data (∞) WE ST TE f (mm) 4.711 7.845 13.215 F _NO 2.800 3.661 5.065 2ω (°) 63.83 38.71 23.29 d ₅ 10.2014 4.7056 1.1213 d ₆ 7.0902 5.5939 1.2485 d ₁₂ 3.0827 9.7051 10.0440 d ₁₆ 0.9858 1.2870 8.7262.

Example 6 r ₁ = -13.4656 (aspherical surface) d ₁ = 3.8736 n _d1 = 1.52540 ν _d1 = 56.25 r ₂ = ∞ (RE) d ₂ = 3.9387 n _d2 = 1.52540 ν _d2 = 56.25 r ₃ = 4.9554 d ₃ = 1.4026 r ₄ = 7.6282 (aspherical surface) d ₄ = 1.4221 n _d3 = 1.84666 ν _d3 = 23.78 r ₅ = 12.9000 d ₅ = (variable) r ₆ = ∞ (aperture) d ₆ = (variable) r ₇ = 5.2791 (aspherical surface) d ₇ = 1.7768 n _d4 = 1.48749 ν _d4 = 70.23 r ₈ = -81.5664 d ₈ = 0.7630 r ₉ = 14.7728 d ₉ = 1.2036 n _d5 = 1.49700 ν _d5 = 81.54 r ₁₀ = 608.0924 d ₁₀ = 0.2054 r ₁₁ = 7.8327 d ₁₁ = 0.7996 n _d6 = 1.84666 ν _d6 = 23.78 r ₁₂ = 4.0971 d ₁₂ = (variable) r ₁₃ = 7.5522 d ₁₃ = 1.7117 n _d7 = 1.49700 ν _d7 = 81.54 r ₁₄ = 28.9115 d ₁₄ = ( Variable) r ₁₅ = 23.0879 (aspherical surface) d ₁₅ = 1.2952 n _d8 = 1.48749 ν _d8 = 70.23 r ₁₆ = -44.5716 d ₁₆ = 1.8191 r ₁₇ = ∞ d ₁₇ = 0.8000 n _d9 = 1.51633 ν _d9 = 64.14 r ₁₈ = _{∞ d 18 = 1.8000 n d10 =} 1.54771 ν d10 = 62.84 r 19 = _{d 19 = 0.5000 r 20 = ∞} d 20 = 0.5000 n d11 = 1.51633 ν d11 = 64.14 r 21 = ∞ d 21 = 1.1990 r 22 = ∞ ( image plane) aspheric coefficients first surface K = 0 A ₄ = 5.7302 × 10 ^-4 A ₆ = -7.8053 × 10 ^-6 A ₈ = 1.0080 × 10 ^-7 A ₁₀ = -6.0371 × 10 ^-10 4th surface K = 1.6311 A ₄ = -3.9850 × 10 ^-4 A ₆ = -1.8434 × 10 ^-5 A ₈ = 1.0561 × 10 ^-6 A ₁₀ = -7.3764 × 10 ^-8 7th surface K = 0 A ₄ = -8.4136 × 10 ^-4 A ₆ = -1.3853 × 10 ^-6 A ₈ = -3.2987 × _{^{10 -6 A 10 = 1.8572 × 10}} -7 15th surface _{K = 0 A 4 = -7.5523 ×} 10 -4 A 6 = 3.6444 × 10 -5 A 8 = -4.4066 × 10 -6 A 10 = 1.5514 × 10 - ⁷ Zoom data (∞) WE ST TE f (mm) 4.622 7.754 13.319 F _NO 2.845 3.848 4.903 2ω (°) 64.02 40.11 23.15 d ₅ 11.2074 6.2877 1.0095 d ₆ 2.9126 0.9995 1.0725 d ₁₂ 3.4738 6.9408 3.6978 d ₁₄ 0.8821 4.2543 12.7013.

Example 7 r ₁ = -189.8868 d ₁ = 4.1631 n _d1 = 1.80400 ν _d1 = 46.57 r ₂ = ∞ (RE) d ₂ = 4.5800 n _d2 = 1.80400 ν _d2 = 46.57 r ₃ = 5.2929 d ₃ = 1.8759 r ₄ = 50.8361 (aspherical surface) d ₄ = 1.4844 n _d3 = 1.84666 ν _d3 = 23.78 r ₅ = -26.1318 d ₅ = (variable) r ₆ = ∞ (aperture) d ₆ = (variable) r ₇ = 16.8412 (non-spherical) Spherical surface) d ₇ = 1.9033 n _d4 = 1.52540 ν _d4 = 56.25 r ₈ = -17.4052 d ₈ = 0.1883 r ₉ = 7.9802 d ₉ = 3.3338 n _d5 = 1.52540 ν _d5 = 56.25 r ₁₀ = -8.6648 d ₁₀ = 0.1854 r ₁₁ = -11.0198 d ₁₁ = 0.7914 n _d6 = 1.58423 ν _d6 = 30.49 r ₁₂ = 5.5614 d ₁₂ = (variable) r ₁₃ = 13.0659 d ₁₃ = 3.4850 n _d7 = 1.48749 ν _d7 = 70.23 r ₁₄ = -19.6309 d ₁₄ = 0.4098 r ₁₅ = -39.9857 d ₁₅ = 1.1678 n _d8 = 1.84666 ν _d8 = 23.78 r ₁₆ = -88.4920 d ₁₆ = (variable) r ₁₇ = 16.9088 (aspherical surface) d ₁₇ = 1.9298 n _d9 = 1.58913 ν _d9 = 61.26 r ₁₈ = 541.6140 d ₁₈ = 0.4530 r ₁₉ = ∞ d ₁₉ = 0.8000 n _d10 = 1. 51633 ν _d10 = 64.14 r ₂₀ = ∞ d ₂₀ = 1.8000 n _d11 = 1.54771 ν _d11 = 62.84 r ₂₁ = ∞ d ₂₁ = 0.5000 r ₂₂ = ∞ d ₂₂ = 0.5000 n _d12 = 1.51633 ν _d12 = 64.14 r ₂₃ = ∞ d ₂₃ = 1.2540 r ₂₄ = ∞ (image plane) Aspherical surface 4th surface K = 60.6915 A ₄ = 5.9084 × 10 ^-4 A ₆ = 6.4597 × 10 ^-8 A ₈ = 7.6149 × 10 ^-7 A ₁₀ = 0.0000 7th Surface K = 0 A ₄ = -3.0428 × 10 ^-4 A ₆ = -8.2590 × 10 ^-6 A ₈ = -4.8028 × 10 ^-7 A ₁₀ = 0.0000 17th surface K = 0 A ₄ = -4.9726 × 10 ^-4 A ₆ = 7.2758 × 10 ^-6 A ₈ = -7.4065 × 10 ^-7 A ₁₀ = 0.0000 Zoom data (∞) WE ST TE f (mm) 4.718 7.844 13.225 F _NO 2.800 3.508 4.967 2ω (°) 63.82 39.04 23.29 d ₅ 10.9875 4.3903 1.1661 d ₆ 5.3096 4.2799 1.0415 d ₁₂ 2.4104 6.8272 4.8660 d ₁₆ 0.9647 3.9776 12.1912.

Example 8 r ₁ = -10.1342 (aspherical surface) d ₁ = 4.2440 n _d1 = 1.52540 ν _d1 = 56.25 r ₂ = ∞ (RE) d ₂ = 4.3830 n _d2 = 1.52540 ν _d2 = 56.25 r ₃ = 5.7723 d ₃ = 1.1659 r ₄ = 8.9304 (aspherical surface) d ₄ = 2.3980 n _d3 = 1.58423 ν _d3 = 30.49 r ₅ = 135.1436 d ₅ = (variable) r ₆ = ∞ (aperture) d ₆ = (variable) r ₇ = 6.0944 (aspherical surface) d ₇ = 2.0738 n _d4 = 1.52540 ν _d4 = 56.25 r ₈ = -92.2200 d ₈ = 1.4429 r ₉ = 13.5033 d ₉ = 1.3149 n _d5 = 1.52540 ν _d5 = 56.25 r ₁₀ = -15.3665 d ₁₀ = 0.0836 r ₁₁ = -21.9405 d ₁₁ = 0.7986 n _d6 = 1.58423 ν _d6 = 30.49 r ₁₂ = 4.5023 d ₁₂ = (variable) r ₁₃ = 8.3099 (aspherical surface) d ₁₃ = 2.8876 n _d7 = 1.52540 ν _d7 = 56.25 r ₁₄ = -14.4805 d ₁₄ = 0.4868 r ₁₅ = -18.1422 d ₁₅ = 0.4953 n _d8 = 1.58423 ν _d8 = 30.49 r ₁₆ = 33.3038 d ₁₆ = (variable) r ₁₇ = 9.5511 (aspherical surface) d ₁₇ = 2.0015 n _d9 = 1.52540 _{ν d9 = 56.25 r 18 = 232.1965} d 18 = 0.5329 r 19 = ∞ _{19 = 0.8000 n d10 = 1.51633 ν} d10 = 64.14 r 20 = ∞ d 20 = 1.8000 n d11 = 1.54771 ν d11 = 62.84 r 21 = ∞ d 21 = 0.5000 r 22 = ∞ d 22 = 0.5000 n d12 = 1.51633 ν d12 = _{64.14 r 23 = ∞ d 23 =} 1.2086 r 24 = ∞ ( image plane) aspheric coefficients first surface _{K = 0 A 4 = 5.9562 ×} 10 -4 A 6 = -3.4519 × 10 -6 A 8 = 2.0786 × 10 - ⁸ A ₁₀ = 6.1688 × 10 ^-11 4th surface K = 0 A ₄ = 1.3932 × 10 ^-4 A ₆ = 6.6203 × 10 ^-7 A ₈ = 2.0911 × 10 ^-7 A ₁₀ = 5.6958 × 10 ^-9 7th surface K = 0 A ₄ = -5.1119 × 10 ^-4 A ₆ = -5.0518 × 10 ^-6 A ₈ = -2.7967 × 10 ^-7 A ₁₀ = -1.1373 × 10 ^-8 13th surface K = 0 A ₄ = -1.2137 × 10 ^-4 A ₆ = -4.6940 × 10 ^-7 A ₈ = -1.4077 × 10 ^-7 A ₁₀ = 6.1129 × 10 ^-9 17th surface K = 0 A ₄ = -3.8511 × 10 ^-4 A ₆ = 1.2674 × 10 ^-5 A ₈ = -1.3956 × 10 ^-6 A ₁₀ = 2.6492 × 10 ^-8 Zoom data (∞) WE ST TE f (mm) 4.623 7.849 13.319 F _NO 2.859 3.699 4.871 2ω (°) 64.94 40.44 23.42 d ₅ 15.7229 7.1467 0.9953 d ₆ 1.8689 0.7843 0.2389 d ₁₂ 1.9376 7.2473 5.1743 d ₁₆ 1.6578 6.0254 14.7931.

Example 9 r ₁ = -19.2526 (aspherical surface) d ₁ = 3.3870 n _d1 = 1.52540 ν _d1 = 56.25 r ₂ = ∞ (RE) d ₂ = 4.2171 n _d2 = 1.52540 ν _d2 = 56.25 r ₃ = 7.3986 d ₃ = 1.7533 r ₄ = -6.8717 (aspherical surface) d ₄ = 0.6000 n _d3 = 1.58913 ν _d3 = 61.14 r ₅ = 102.4738 d ₅ = 0.1041 r ₆ = 23.1052 d ₆ = 1.2073 n _d4 = 1.84666 ν _d4 = 23.78 r ₇ = -28.8750 d ₇ = (variable) r ₈ = ∞ (aperture) d ₈ = (variable) r ₉ = 10.8736 (aspherical surface) d ₉ = 1.7462 n _d5 = 1.48749 ν _d5 = 70.23 r ₁₀ = -17.3749 d ₁₀ = 0.7800 r ₁₁ = 7.8941 d ₁₁ = 1.9466 n _d6 = 1.48749 ν _d6 = 70.23 r ₁₂ = -25.2485 d ₁₂ = 0.1909 r ₁₃ = 14.9995 d ₁₃ = 0.9977 n _d7 = 1.84666 ν _d7 = 23.78 r ₁₄ = 5.5617 d ₁₄ = (Variable) r ₁₅ = 11.8764 d ₁₅ = 1.4461 n _d8 = 1.48749 ν _d8 = 70.23 r ₁₆ = 216.5874 d ₁₆ = (Variable) r ₁₇ = 25.5732 (aspherical) d ₁₇ = 1.3436 n _d9 = 1.48749 ν _d9 = 70.23 r ₁₈ = -30.6630 d ₁₈ = 0.6739 r ₁₉ = ∞ d ₁₉ = 0.800 0 n _d10 = 1.51633 ν _d10 = 64.14 r ₂₀ = ∞ d ₂₀ = 1.8000 n _d11 = 1.54771 ν _d11 = 62.84 r ₂₁ = ∞ d ₂₁ = 0.5000 r ₂₂ = ∞ d ₂₂ = 0.5000 n _d12 = 1.51633 ν _d12 = 64.14 r ₂₃ = ∞ d ₂₃ = 1.2106 r ₂₄ = ∞ (image plane) Aspheric coefficient 1st surface K = 0 A ₄ = 3.9598 × 10 ^-4 A ₆ = -2.6023 × 10 ^-6 A ₈ = 2.3562 × 10 ^-8 A ₁₀ = -8.3693 × 10 ^-11 4th surface K = 0 A ₄ = -3.8167 × 10 ^-4 A ₆ = -3.1958 × 10 ^-5 A ₈ = 1.2150 × 10 ^-6 A ₁₀ = -4.8364 × 10 ^-8 9th surface K = 0 A ₄ = -5.3606 × 10 ^-4 A ₆ = 2.8019 × 10 ^-6 A ₈ = -4.5232 × 10 ^-7 A ₁₀ = 1.9681 × 10 ^-8 17th surface K = 0 A ₄ = -6.4954 × 10 ^-4 A ₆ = 1.3860 × 10 ^-5 A ₈ = -1.5906 × 10 ^-6 A ₁₀ = 4.6245 × 10 ^-8 Zoom data (∞) WE ST TE f (mm) 4.620 7.913 13.319 F _NO 2.800 3.627 4.696 2ω (°) 65.02 39.11 23.15 d ₇ 10.2487 4.9877 0.9993 d ₈ 1.7588 0.5222 0.5222 d ₁₄ 7.6958 8.4509 1.6784 d ₁₆ 0.3855 6.1464 16.9092.

Example 10 r ₁ = −20.8821 (aspherical surface) d ₁ = 4.0207 n _d1 = 1.52540 ν _d1 = 56.25 r ₂ = ∞ (RE) d ₂ = 3.5901 n _d2 = 1.52540 ν _d2 = 56.25 r ₃ = 6.3359 d ₃ = 1.7900 r ₄ = -8.4727 (aspherical surface) d ₄ = 0.6000 n _d3 = 1.58913 ν _d3 = 61.14 r ₅ = 68.9126 d ₅ = 0.2927 r ₆ = 17.5359 d ₆ = 1.2385 n _d4 = 1.84666 ν _d4 = 23.78 r ₇ = -63.0628 d ₇ = (variable) r ₈ = ∞ (aperture) d ₈ = (variable) r ₉ = 10.4538 (aspherical surface) d ₉ = 1.7744 n _d5 = 1.48749 ν _d5 = 70.23 r ₁₀ = -18.4306 d ₁₀ = 0.7819 r ₁₁ = 7.2340 d ₁₁ = 1.9210 n _d6 = 1.48749 ν _d6 = 70.23 r ₁₂ = -40.1886 d ₁₂ = 0.1762 r ₁₃ = 12.7214 d ₁₃ = 0.9941 n _d7 = 1.84666 ν _d7 = 23.78 r ₁₄ = 5.0951 d ₁₄ = (Variable) r ₁₅ = 11.6216 d ₁₅ = 1.4485 n _d8 = 1.48749 ν _d8 = 70.23 r ₁₆ = 121.4804 d ₁₆ = (Variable) r ₁₇ = 20.4476 (aspherical) d ₁₇ = 1.3615 n _d9 = 1.48749 ν _d9 = 70.23 r ₁₈ = -46.8568 d ₁₈ = 0.7220 r ₁₉ = ∞ d ₁₉ = 0.8 000 n _d10 = 1.51633 ν _d10 = 64.14 r ₂₀ = ∞ d ₂₀ = 1.8000 n _d11 = 1.54771 ν _d11 = 62.84 r ₂₁ = ∞ d ₂₁ = 0.5000 r ₂₂ = ∞ d ₂₂ = 0.5000 n _d12 = 1.51633 ν _d12 = 64.14 r ₂₃ = ∞ d ₂₃ = 1.2105 r ₂₄ = ∞ (image plane) Aspheric coefficient 1st surface K = 0 A ₄ = 3.5893 × 10 ^-4 A ₆ = -2.9343 × 10 ^-6 A ₈ = 2.4501 × 10 ^-8 A ₁₀ = -5.9072 × 10 ^-11 4th surface K = 0 A ₄ = -3.1690 × 10 ^-4 A ₆ = -2.9007 × 10 ^-5 A ₈ = 2.2534 × 10 ^-6 A ₁₀ = -1.4959 × 10 ^-7 9th surface K = 0 A ₄ = -4.6904 × 10 ^-4 A ₆ = -7.9492 × 10 ^-6 A ₈ = 1.3859 × 10 ^-6 A ₁₀ = -8.9399 × 10 ^-8 17th surface K = 0 A ₄ =- 5.8918 × 10 ^-4 A ₆ = 3.8393 × 10 ^-6 A ₈ = -2.6557 × 10 ^-7 A ₁₀ = -9.7926 × 10 ^-9 Zoom data (∞) WE ST TE f (mm) 4.627 7.797 13.318 F _NO 2.800 3.527 4.718 2ω (°) 64.82 39.60 23.15 d ₇ 10.3069 4.6640 0.9983 d ₈ 1.7881 1.1133 0.5900 d ₁₄ 7.5155 8.4461 1.5276 d ₁₆ 0.3719 5.7768 16.8824.

FIG. 11 is an aberration diagram of Example 1 upon focusing on an object point at infinity. In this aberration diagram, SA indicates spherical aberration, AS indicates astigmatism, CC indicates lateral chromatic aberration, and DT indicates distortion. In the figure, "FIY" represents the image height.

Next, the conditions (1)-
Nd, f related to (5)_1G/ √ (f _wXf_t), M₃/
M₂, -Β_Rt, DFT / f_tIndicates the value of. Example nd f_1G/ √ (f_wXf_t) M₃/ M₂  -Β_Rt  DFT / f_t   1 1.5254 -1.0699 1.365 1.586 0.106   2 1.5254 -1.0027 1.568 1.693 0.110   3 1.8830 -0.9083 1.465 1.895 0.109   4 1.8061 -1.3160 0.863 1.277 0.355   5 1.8040 -1.4003 0.533 1.196 0.760   6 1.5254 -1.2545 0.981 1.353 0.278   7 1.8040 -1.3917 0.826 1.203 0.368   8 1.5254 -1.6145 0.802 1.051 0.388   9 1.5254 -0.9674 1.651 1.755 0.126 10 1.5254 -0.9743 1.643 1.741 0.115                                                                       .

In the above Examples 1 to 10, the following d
The transition point Tg of a glass having a line refractive index n _d and an Abbe number ν _d is as follows.

N _d ν _d Tg (° C.) 1.58913 61.14 525 1.48749 70.23 500 1.80809 22.76 552 1.58913 61.26 515 1.84666 23.78 619.

In each of the above embodiments, the medium having the following d-line refractive index n _d and Abbe number ν _d is plastic.

N _d ν _d 1.52540 56.25 1.58423 30.49.

In each of the above embodiments, the optical path bending prism P provided with the aspherical surface is provided with the aspherical surface on the incident surface, but the aspherical surface may be provided on the exit surface.

In all of the above embodiments, the prism P is used as the first element on the most object side of the optical system.
As schematically shown in FIG. 12, a single lens or a plurality of lens groups A including a plurality of lenses are arranged on the front side (object side) of the prism P, and the lens group A is arranged along the optical axis for focusing or zooming. You may make it move.

In the optical path bending zoom optical system of the present invention as described above, an object image is formed by a focusing optical system such as a zoom lens, and the image is picked up by an image pickup device such as a CCD or a silver salt film for photographing. The present invention can be used for a photographing device to be performed, especially a digital camera or a video camera, a personal computer which is an example of an information processing device, a telephone, a mobile terminal, particularly a mobile phone which is convenient to carry. The embodiment will be exemplified below.

FIGS. 13 to 15 are conceptual diagrams showing a configuration in which the zoom optical system according to the present invention is incorporated in the photographing optical system 41 of a digital camera. 13 is a front perspective view showing the external appearance of the digital camera 40, FIG. 14 is a rear perspective view of the same, and FIG. 15 is a sectional view showing the configuration of the digital camera 40. 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, and a flash 4.
6. When the shutter 45, which includes the liquid crystal display monitor 47 and the like and is disposed above the camera 40, is pressed, the photographing is performed through the photographing optical system 41, for example, the optical path bending zoom optical system of the fifth embodiment. 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 and the optical low pass filter in the plane-parallel plate group F. 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. The recording means 52 may be provided separately from the processing means 51, or may be configured to record and write electronically by a floppy (registered trademark) disk, a memory card, an MO, or the like. Further, it may be configured as a silver salt camera in which a silver salt film is arranged instead of the CCD 49.

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
Since the photographic optical system 41 is a zoom lens having a wide angle of view, a high zoom ratio, good aberrations, a high brightness, and a large back focus in which filters and the like can be arranged, high performance and low cost can be realized.

In the example of FIG. 15, a plane parallel plate is arranged as the cover member 50, but a lens having power may be used.

Next, FIGS. 16 to 18 show a personal computer as an example of an information processing apparatus in which the zoom optical system of the present invention is incorporated as an objective optical system. 16 is a front perspective view of the personal computer 300 with the cover opened, FIG. 17 is a sectional view of the taking optical system 303 of the personal computer 300, and FIG. 18 is a side view of the state of FIG. As shown in FIG. 16 to FIG. 18, the personal computer 300 includes a keyboard 301 for the preparer to input information from the outside, an information processing means and a recording means (not shown), and a monitor for displaying the information to the operator. 302 and a photographing optical system 303 for photographing an image of the operator himself or herself
And have. 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. Also,
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.

This photographing optical system 303 has a photographing optical path 304.
An objective lens 112 including an optical path bending zoom optical system (abbreviated in the drawing) according to the present invention and an image pickup device chip 162 that receives an image are provided on the top. These are PC 3
It is built into 00.

Here, an optical low-pass filter LF is additionally attached on the image pickup element chip 162 to integrally form an image pickup unit 160, and the objective lens 1
Since it can be fitted and attached to the rear end of the lens frame 113 of No. 12 with one touch, the centering of the objective lens 112 and the image pickup device chip 162 and the adjustment of the surface interval are unnecessary, and the assembly is easy. . Further, a cover glass 114 for protecting the objective lens 112 is arranged at the tip (not shown) of the lens frame 113. The lens frame 11
The drive mechanism and the like of the zoom lens in 3 are 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. In FIG. A photographed image 305 of the person is shown. 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. 19 shows a telephone, which is an example of an information processing apparatus in which the zoom optical system of the present invention is incorporated as a photographing optical system, particularly a portable telephone which is convenient to carry. FIG. 19
19A is a front view of the mobile phone 400, FIG. 19B is a side view, and FIG. 19C is a sectional view of the photographing optical system 405.
As shown in FIGS. 19A to 19C, the mobile phone 40
0 indicates a microphone unit 401 for inputting the operator's voice as information.
A speaker unit 402 for outputting the voice of the other party, an input dial 403 for the operator to input information, a monitor 404 for displaying a photographed image of the operator himself or the other party and information such as a telephone number, and photographing. An optical system 405, an antenna 406 for transmitting and receiving communication radio waves, image information and communication information,
And processing means (not shown) for processing the input signal 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 includes an objective lens 112 which is arranged on a photographing optical path 407 and includes an optical path bending zoom optical system (not shown in the figure) according to the present invention, and an image pickup element chip 162 which receives an object image. . These are built into the mobile phone 400.

Here, an optical low-pass filter LF is additionally attached on the image pickup element chip 162 to integrally form an image pickup unit 160, and the objective lens 1
Since it can be fitted and attached to the rear end of the lens frame 113 of No. 12 with one touch, the centering of the objective lens 112 and the image pickup device chip 162 and the adjustment of the surface interval are unnecessary, and the assembly is easy. . Further, a cover glass 114 for protecting the objective lens 112 is arranged at the tip (not shown) of the lens frame 113. The lens frame 11
The drive mechanism and the like of the zoom lens in 3 are not shown.

The object image received by the image pickup element chip 162 is input to the processing means (not shown) via the terminal 166, and is displayed on the monitor 404 as an electronic image, 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.

The above-described optical path bending zoom optical system of the present invention and an apparatus using the same can be configured as follows, for example.

[1] At least a first lens group having a negative refracting power, a second lens group having a positive refracting power, and at least one lens group after that, in order from the object side, at a wide angle end. At least 1 that moves along the optical axis including the second lens group when zooming from the zoom lens to the telephoto end
In a zoom optical system including two lens groups, the first lens group has a prism including at least one reflecting surface for bending an optical path, an entrance surface, and an exit surface, and the entrance surface of the prism, An optical path bending zoom optical system, wherein at least one of the exit surfaces is a curved surface that is rotationally symmetric with respect to the optical axis.

[2] At least in order from the object side, a prism having a negative refracting power and at least a negative refracting power is set to 1
And a second lens group having a positive refracting power, and at least one lens group thereafter, including the second lens group when zooming from the wide-angle end to the telephoto end. In the zoom optical system including at least one lens group that moves along the optical axis at, the prism includes at least one reflecting surface for bending an optical path, an entrance surface, and an exit surface, and At least one of the entrance surface and the exit surface is a curved surface.

[3] At least a first lens group having a negative refracting power, a second lens group having a positive refracting power, and at least one lens group after that in order from the object side, at the wide angle end. At least 1 that moves along the optical axis, including the second lens group, when zooming from the zoom lens to the telephoto end
In a zoom optical system including two lens groups, the first lens group has a prism including at least one reflecting surface for bending an optical path, an entrance surface, and an exit surface, and the entrance surface of the prism, At least one of the exit surfaces is a curved surface, and the refractive index nd of the prism at the d-line satisfies the following conditional expression (1), the optical path bending zoom optical system.

1.6 <nd <2.0 (1) [4] In any one of the above items 1 to 3, the following optical path bending zoom optics is characterized by satisfying the following conditional expression (2). system.

−5.0 <f _1G / √ (f _w × f _t ) <− 0.3 (2) where f _1G is the focal length of the first lens group and f _w is the wide-angle end. The focal length of the entire system when focusing on an object point at infinity, and f _t is the focal length of the entire system when focusing on an object point at infinity at the telephoto end.

[5] In any one of the above items 1 to 3, the third lens element having a positive refractive power is provided after the second lens group.
An optical path bending zoom including a lens group, wherein the second lens group and the third lens group move along the optical axis while changing the relative distance when zooming from the wide-angle end to the telephoto end. Optical system.

[6] In the above-mentioned item 5, the moving amounts of the second lens unit and the third lens unit at the time of zooming from the wide-angle end to the telephoto end when focusing on infinity are M ₂ and M ₃ , respectively. An optical path bending zoom optical system characterized by satisfying the following conditional expression (3).

0.3 <M ₃ / M ₂ <3.0 (3) [7] In the above 5, the magnification β _Rt of the compound system after the second lens group at the telephoto end is the following conditional expression: An optical path bending zoom optical system characterized by satisfying (4).

1.0 <−β _Rt <2.3 (4) [8] In any one of the above items 1 to 3, the lens group closest to the image side has at least one aspherical surface. A characteristic optical path bending zoom optical system.

[0167]

[9] In the above-mentioned 8, the optical path bending zoom optical system is characterized in that the lens unit closest to the image side is fixed during zooming and focusing.

[10] The optical path bending zoom optical system as described in 9 above, wherein the second lens unit from the image side is moved in the optical axis direction for focusing.

[11] The optical path bending zoom optical system described in any one of 1 to 3 above, wherein the first lens group has at least one aspherical surface.

[12] In the above-mentioned 11, the optical path bending zoom optical system is characterized in that the first lens group is fixed during zooming and focusing.

[13] In any one of the above items 1 to 3, the lens group disposed on the image side of the prism or a part of the lenses in the lens group disposed on the image side of the prism is irradiated with light. An optical path bending zoom optical system characterized by focusing by moving in the axial direction.

[14] In the above item 10, 2 from the image side
An optical path bending zoom optical system characterized in that the air distance DFT on the optical axis at the time of focusing on an object point at infinity at the telephoto end of the third lens group and the third lens group satisfies the following conditional expression (5). .

0.01 <DFT / f _t <2.0 (5) where f _t is the focal length of the entire system when focusing on an object point at infinity at the telephoto end.

[15] In the above-mentioned 5, the first lens group is composed of one prism having a negative refractive power, one negative lens and one positive lens, and the third lens group is one. An optical path bending zoom optical system, which is composed of a single positive lens.

[16] In the above-mentioned 5, the first lens group includes one prism having a negative refractive power and one positive lens, and the third lens group includes one positive lens. An optical path bending zoom optical system comprising one negative lens.

[17] An optical path bending zoom optical system as described in 15 or 16 above, wherein focusing is performed by moving the third lens group in the optical axis direction.

[18] The optical path bending zoom optical system as described in 11 above, wherein at least one of the entrance surface and the exit surface of the prism is an aspherical surface.

[19] The optical path bending zoom optical system according to the above 8 or 11, wherein the lens or prism having an aspherical surface is made of glass and the transition point Tg thereof satisfies the following conditional expression (6). .

60 ° C. <Tg <620 ° C. (6) [20] In the above 8 or 11, the lens or prism having an aspherical surface is processed by a glass molding method to bend an optical path. Zoom optics.

[21] The optical path bending zoom optical system described in 8 or 11 above, wherein the lens or prism having an aspherical surface is made of an organic-inorganic hybrid material.

[22] The optical path bending zoom optical system according to the above 8 or 11, wherein the lens or prism having an aspherical surface is made of plastic.

[23] The optical path bending zoom optical system as described in any one of 1 to 3 above, wherein the prism is made of plastic.

[24] An optical path bending zoom optical system according to any one of 1 to 3 above, wherein all the lenses and prisms are made of plastic.

[25] In any one of the above items 1 to 3, the optical axis is bent so that the bent surface of the optical axis is parallel to the short side of the image pickup surface of the image pickup element arranged on the image plane. Optical path bending zoom optical system characterized by.

[26] In any one of the above items 1 to 3, the prism is arranged closer to the object side than the most object side lens of all the lens groups that are movable during zooming. Optical path bending zoom optical system.

[27] In any one of items 1 to 3 above, the lens group that moves during zooming moves monotonously to the object side when zooming from the wide-angle end to the telephoto end. Optical path bending zoom optical system.

[28] An optical path bending zoom optical system according to any one of 1 to 3 above, wherein at least one aperture stop is arranged on the optical path on the image side of the prism.

[29] The optical path bending zoom optical system as described in 5 above, wherein the third lens group is moved in the optical axis direction for focusing.

[30] The optical path bending zoom optical system described in any one of the above items 1 to 29, an electronic image pickup device arranged at a position for receiving an object image formed by the optical path bending zoom optical system, Processing means for processing an electronic signal photoelectrically converted by the electronic image pickup device, an input section for an operator to input an information signal desired to be input to the processing means, and a display element for displaying an output from the processing means, A recording medium for recording the output from the processing means, wherein the processing means is configured to display an object image received by the electronic image pickup device by the optical path bending zoom optical system on the display device. An information processing device characterized by the above.

[31] In the above item 30, the input unit is constituted by a keyboard, and the optical path bending zoom optical system and the electronic image pickup device are built in the peripheral portion of the display element or the peripheral portion of the keyboard. A personal computer device characterized in that

[32] The optical path bending zoom optical system according to any one of the above items 1 to 29, an electronic image pickup device arranged at a position for receiving an object image formed by the optical path bending zoom optical system, and a telephone. An antenna for transmitting and receiving signals, an input unit for inputting a signal such as a telephone number, and a signal processing unit for converting an object image received by the electronic image pickup device into a transmittable signal are included. A telephone device characterized by being installed.

[33] The optical path bending zoom optical system described in any one of the above items 1 to 29, an electronic image pickup element arranged at a position for receiving an object image formed by the optical path bending zoom optical system, and An object image received by the electronic image pickup device, which has a processing means for processing an electronic signal photoelectrically converted by the electronic image pickup device and a display device for observably displaying the object image received by the electronic image pickup device. A recording member for recording image information of the electronic device, the processing device displaying the object image received by the electronic image pickup device on the display device, and the electronic device. An electronic camera device having a recording processing function of recording an object image received by an image sensor on the recording medium.

[0193]

As is apparent from the above description, according to the present invention, there is provided a thin zoom optical system that can be mounted on a compact digital still camera, a mobile terminal, etc. It is possible to provide an optical path bending zoom optical system in which a bending prism has power.

[Brief description of drawings]

FIG. 1 is a first embodiment of an optical path bending zoom optical system according to the present invention.
Wide-angle end (a), intermediate state (b) when focusing on an object point at infinity of
It is a lens cross-sectional view at the telephoto end (c).

2 is a lens cross-sectional view similar to FIG. 1 of an optical path bending zoom optical system of Example 2. FIG.

3 is a lens cross-sectional view similar to FIG. 1 of an optical path bending zoom optical system of Example 3. FIG.

FIG. 4 is a lens cross-sectional view similar to FIG. 1 of an optical path bending zoom optical system of Example 4.

5 is a lens cross-sectional view similar to FIG. 1 of the optical path bending zoom optical system of Example 5. FIG.

6 is a lens cross-sectional view similar to FIG. 1 of the optical path bending zoom optical system of Example 6. FIG.

7 is a lens cross-sectional view similar to FIG. 1 of the optical path bending zoom optical system of Example 7. FIG.

8 is a lens cross-sectional view similar to FIG. 1 of the optical path bending zoom optical system of Example 8. FIG.

9 is a lens cross-sectional view similar to FIG. 1 of the optical path bending zoom optical system of Example 9. FIG.

10 is a lens cross-sectional view similar to FIG. 1 of the optical path bending zoom optical system of Example 10. FIG.

FIG. 11 is an aberration diagram for Example 1 upon focusing on an object point at infinity.

FIG. 12 is a diagram schematically showing a configuration of a modified example of the optical path bending zoom optical system of the present invention.

FIG. 13 is a front perspective view showing the appearance of a digital camera incorporating the optical path bending zoom optical system according to the present invention.

FIG. 14 is a rear perspective view of the digital camera shown in FIG.

15 is a cross-sectional view of the digital camera shown in FIG.

FIG. 16 is a front perspective view of the personal computer in which the optical path bending zoom optical system according to the present invention is incorporated as an objective optical system with the cover open.

FIG. 17 is a sectional view of a photographing optical system of a personal computer.

FIG. 18 is a side view of the state of FIG.

FIG. 19 is a front view, a side view, and a side view of a mobile phone in which the optical path bending zoom optical system according to the present invention is incorporated as an objective optical system.
It is a sectional view of the photographing optical system.

[Explanation of symbols]

G1 ... First lens group G2: Second lens group G3 ... Third lens group G4 ... 4th lens group P ... Optical path bending prism S ... Aperture stop (when independent) F: Parallel plane plate group I ... Image plane A: Focusing lens group or zooming lens group E ... Observer eye LF ... Optical low pass filter 40 ... Digital camera 41 ... Shooting optical system 42 ... Optical path for photography 43 ... Finder optical system 44 ... Optical path for finder 45 ... Shutter 46 ... Flash 47 ... LCD 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 112 ... Objective lens 113 ... Mirror frame 114 ... Cover glass 160 ... Imaging unit 162 ... Image sensor chip 166 ... Terminal 300 ... PC 301 ... Keyboard 302 ... Monitor 303 ... Shooting optical system 304 ... Shooting optical path 305 ... Image 400 ... Mobile phone 401 ... Microphone part 402 ... Speaker unit 403 ... Input dial 404 ... Monitor 405 ... Photography optical system 406 ... Antenna 407 ... Shooting optical path

Continued front page    (72) Inventor Toshiyuki Nagaoka             2-43 Hatagaya, Shibuya-ku, Tokyo Ori             Inside Npus Optical Industry Co., Ltd. F term (reference) 2H087 KA03 PA08 PA17 PB08 QA02                       QA03 QA17 QA19 QA21 QA22                       QA25 QA32 QA34 QA41 QA42                       QA45 QA46 RA05 RA12 RA13                       RA36 RA41 RA42 RA44 SA22                       SA26 SA29 SA32 SA63 SA64                       SA72 SA75 SB03 SB04 SB14                       SB22 SB23 SB32 TA01 TA03                       UA01                 5C022 AA13 AB66 AC54 AC55

Claims (3)

[Claims] 1. A first lens unit having a negative refracting power, a second lens unit having a positive refracting power, and at least one lens unit after that, in order from the object side, from the wide-angle end. In a zoom optical system including at least one lens group that includes the second lens group and moves along the optical axis when zooming to the telephoto end, the first lens group includes at least one lens for bending an optical path. An optical path bending zoom optical system having a prism including a reflecting surface, an entrance surface, and an exit surface, and at least one of the entrance surface and the exit surface of the prism is a curved surface rotationally symmetrical with respect to an optical axis. system. 2. A first lens group having a negative refracting power and including at least one prism having a negative refracting power in order from the object side, a second lens group having a positive refracting power, and thereafter. In a zoom optical system including at least one lens group, the zoom optical system including at least one lens group including the second lens group and moving along the optical axis when zooming from the wide-angle end to the telephoto end, The prism has at least one for bending the optical path.
An optical path bending zoom optical system including a reflecting surface, an entrance surface, and an exit surface, and at least one of the entrance surface and the exit surface is a curved surface. 3. A first lens group having a negative refracting power, a second lens group having a positive refracting power, and at least one lens group after that at least in order from the object side, from the wide-angle end. In a zoom optical system including at least one lens group that includes the second lens group and moves along the optical axis when zooming to the telephoto end, the first lens group includes at least one lens for bending an optical path. A prism including a reflecting surface, an entrance surface, and an exit surface, at least one of the entrance surface and the exit surface of the prism is a curved surface, and the refractive index n at the d line of the prism is
An optical path bending zoom optical system, wherein d satisfies the following conditional expression (1). 1.6 <nd <2.0 (1)