JP2006003547A - Variable power optical system and electronic equipment using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable power optical system which is constituted of a small number of lenses, whose axial chromatic aberrations are fully corrected, and which effectively realizes the compatibility of cost reduction and miniaturization, and to provide electronic equipment. <P>SOLUTION: The variable power optical system where a lens group G1 nearest to an object side has negative refractive power and which is equipped with at least a 2nd lens group G2 and a 3rd lens group G3, in this order starting from the object side satisfies the conditional expression at varying of power from a wide-angle end to a telephoto end (1): -2<¾d<SB>W12</SB>-d<SB>t12</SB>¾/¾d<SB>W23</SB>-d<SB>t23</SB>¾<300, where d<SB>W12</SB>is the space between the 1st lens group and the 2nd lens group at the wide angle end, d<SB>t12</SB>is the space between the 1st lens group and the 2nd lens group at the telephoto end, d<SB>W23</SB>is the space between the 2nd lens group and the 3rd lens group at the wide angle end, and d<SB>t23</SB>is the space between the 2nd lens group and the 3rd lens group at the telephoto end. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a variable magnification optical system and an electronic apparatus using the same, and more particularly to a compact variable magnification optical system and an electronic apparatus using such a variable magnification optical system. Examples of the electronic apparatus include a digital camera, a video camera, a digital video unit, a personal computer, a mobile computer, a mobile phone, and an information portable terminal.

In recent years, portable information terminals and mobile phones called PDAs have become explosive. Many of these devices have built-in compact digital cameras and digital video units. Here, in these digital cameras and digital video units, a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) sensor is used as an imaging device. In such a digital camera or the like, an image sensor having a relatively small effective area of the light receiving surface is used. Therefore, when downsizing such a digital camera or the like, it is necessary to achieve both miniaturization and cost reduction while maintaining high performance of the optical system. Conventionally, as one of the downsized and low-cost optical systems, there are two disclosed optical systems such as Patent Document 1, Patent Document 2, and Patent Document 3. In order from the object side, an optical system composed of a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having negative refractive power, abbreviated negative positive / negative variable power optical system It is.
JP-A-3-150518 Japanese Patent Laid-Open No. 3-158816 JP-A-3-260611

  However, when configuring each lens group with a small number of lenses for miniaturization, removal of chromatic aberration is a problem in the negative / positive / negative variable magnification optical system. The optical systems described in Patent Document 2 and Patent Document 3 use high-dispersion glass materials for the first lens group and low-dispersion glass materials for the second lens group, respectively. Further, in the optical system disclosed in Patent Document 1, the number of lenses is increased in order to form a low-cost glass material, and it cannot be said that the effects of cost reduction and size reduction are sufficient.

  The present invention has been made in view of such a situation in the prior art, and its purpose is to sufficiently correct axial chromatic aberration with a small number of lenses, and to achieve both cost reduction and downsizing. It is another object of the present invention to provide a variable magnification optical system and an electronic apparatus using the same.

  In the first variable power optical system of the present invention, the lens unit closest to the object side has negative refractive power, and the variable power optical system further includes at least a second lens group and a third lens group in order from the object side. The following conditional expression is satisfied at the time of zooming from the wide-angle end to the telephoto end.

2 <| d _w12 −d _t12 | / | d _w23 −d _t23 | <300 (1)
Where d _w12 : the distance between the first lens group and the second lens group at the wide-angle end,
d _t12 : the distance between the first lens group and the second lens group at the telephoto end,
d _w23 : the distance between the second lens group and the third lens group at the wide-angle end,
d _t23 : the distance between the second lens group and the third lens group at the telephoto end,
It is.

  Hereinafter, the reason and operation of the first variable magnification optical system will be described.

  The reason why the first lens group has a negative refractive power is to reduce the volume of the first lens group itself by positioning the entrance pupil position as close to the object side as possible.

  If the number of the second lens group is reduced in order to reduce the cost, the variation of the axial chromatic aberration accompanying the zooming in the second lens group becomes large. At this time, by satisfying conditional expression (1), the second lens unit and the third lens unit move while approaching at the time of zooming. Therefore, axial chromatic aberration can be canceled by the second lens group and the third lens group. Therefore, the fluctuation | variation accompanying zooming can be suppressed. Exceeding the upper limit of 300 in the conditional expression (1) indicates that the distance between the second lens group and the third lens group hardly changes with zooming. Therefore, if the upper limit of 300 in the conditional expression (5) is exceeded, in a negative / positive / negative optical system configured with a small number of lenses, the image plane moves only by moving the second lens group and the third lens group accompanying zooming. Cannot be corrected. In this case, the movement of the first lens group is indispensable for obtaining a good image. Therefore, since the number of moving groups increases, the mechanism is complicated. Thus, exceeding the upper limit is not preferable in terms of cost reduction and size reduction. If the lower limit value of 2 is not reached, fluctuations in axial chromatic aberration due to zooming cannot be suppressed. In this case, the image quality at the center of the image deteriorates. Therefore, it is not preferable to fall below the lower limit.

  Furthermore, it is preferable that the following conditional expression (1-2) is satisfied. By satisfying this condition, it is possible to reduce the fluctuation of axial chromatic aberration due to zooming.

5 <| d _w12 −d _t12 | / | d _w23 −d _t23 | <100 (1-2)
Furthermore, it is preferable that the following conditional expression (1-3) is satisfied. By satisfying this condition, it is possible to reduce the fluctuation of axial chromatic aberration due to zooming.

7 <| d _w12 −d _t12 | / | d _w23 −d _t23 | <80 (1-3)
A second variable magnification optical system according to the present invention includes, in the first variable magnification optical system, in order from the object side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, A variable magnification optical system including a third lens group having a negative refractive power, characterized in that the following conditional expressions are satisfied simultaneously.

1.5 <β <30 (2)
0.5 <L _t / L _w <1.3 (3)
Where β is the zoom ratio of the optical system,
L _t : Optical total length at the telephoto end,
L _w : Optical total length at the wide-angle end,
It is.

  Hereinafter, the reason and operation of the second variable magnification optical system will be described.

  An optical system with a fixed overall length can be realized with a small number of lenses and a short overall length. Therefore, the negative / positive / negative variable power optical system can realize a compact and low-cost optical system. In such a negative / positive / negative variable power optical system, the optical total length (the length from the first lens system surface to the image plane) is shorter than the total optical system length at the wide angle end. By doing so, the optical system becomes more compact. Therefore, the number of collapsible steps can be reduced, or the mechanical mechanism can be simplified. Condition (2) is a precondition for conditional expression (3). At this time, by satisfying the conditional expression (3), the overall length can be shortened while maintaining good performance. If the upper limit of 1.3 in conditional expression (3) is exceeded, the lens group operating range becomes large and the optical total length becomes long. Therefore, exceeding the upper limit is not preferable for downsizing. Further, since the lens group moves further to the object side, the light flux becomes smaller. For this reason, the F number is particularly large at the telephoto end, which is not preferable. If the lower limit of 0.5 in conditional expression (3) is not reached, the lens group operating range becomes large and the cost increases. Therefore, it is not preferable to fall below the lower limit.

  Furthermore, the following conditional expressions (2-2) and (3-2) are preferably satisfied. By satisfying this condition, an optical system having a short overall length can be realized while maintaining good performance.

1.5 <β <10 (2-2)
0.6 <L _t / L _w <1.2 (3-2)
Furthermore, the following conditional expressions (2-3) and (3-3) are preferably satisfied. By satisfying this condition, an optical system having a short overall length can be realized while maintaining good performance.

1.5 <β <5 (2-3)
0.7 <L _t / L _w <1.1 (3-3)
A third variable power optical system according to the present invention is characterized in that, in the first and second variable power optical systems, the following conditional expressions are satisfied simultaneously at the time of zooming from the wide-angle end to the telephoto end. is there.

_{β 23t <-1 <β 23w ···} (4)
−0.2 <(d _w23 −d _t23 ) / f _w <0.2 (5)
Where β _23w is the combined lateral magnification at the wide angle end of the optical system after the second lens group,
β _23t : Composite lateral magnification at the telephoto end of the optical system after the second lens group,
d _w23 : group interval between the second lens unit and the third lens unit at the wide-angle end,
d _t23 : the distance between the second lens group and the third lens group at the telephoto end,
f _w : focal length of the entire system at the wide-angle end,
It is.

  Hereinafter, the reason and operation of the third variable magnification optical system will be described.

  At the time of zooming from the wide-angle end to the telephoto end, the combined lateral magnification of the optical system after the second lens group includes a magnification of −1. By doing so (conditional expression (4)), the amount of movement of the first lens group can be suppressed. As a result, an optical system with a short overall length can be constructed.

  By the way, the third variable power optical system is a negative positive / negative optical system. Here, when this configuration is considered as a two-group configuration, it can be said to be an optical system based on a negative and positive refractive power arrangement. In the negative positive optical system, the negative lens group functions as a compensator, and the positive lens group functions as a variator. Therefore, in the present application, the first lens group functions as a compensator, and the second and third lens groups function as a variator.

  Therefore, in the present invention, the group interval between the second and third lens groups is slightly changed. In this way, the positional relationship between the object point and the image point in the second and third lens groups does not change greatly with zooming. That is, since the fluctuation of the image plane is small, the movement amount of the first lens group can be suppressed. In addition, it is possible to suppress the fluctuation amount of the optical total length (the length from the lens system first surface to the image surface). As a result, cost reduction and size reduction can be realized. At this time, by satisfying the conditional expression (5), it is possible to suppress the variation in the total length while keeping the performance good. When the upper limit of 0.2 in conditional expression (5) is exceeded, the distance between the principal points of the second lens group and the third lens group at the wide-angle end increases. In this case, spherical aberration and axial chromatic aberration are greatly deteriorated. Therefore, aberration variation cannot be suppressed with a small number of lenses. Therefore, it is not preferable to exceed the upper limit value. If the lower limit of −0.2 of conditional expression (5) is not reached, the amount of variation in the first lens group is large, and the variation in image position cannot be corrected with a small number of lenses. Therefore, it is not preferable to fall below the lower limit.

  Furthermore, it is preferable to satisfy the following conditional expression (5-2). By satisfying this condition, the overall length can be shortened while maintaining good performance.

−0.15 <(d _w23 −d _t23 ) / f _w <0.15 (5-2)
Furthermore, it is preferable that the following conditional expression (5-3) is satisfied. By satisfying this condition, the overall length can be shortened while maintaining good performance.

−0.1 <(d _w23 −d _t23 ) / f _w <0.1 (5-3)
A fourth variable magnification optical system according to the present invention is characterized in that, in the first to third variable magnification optical systems, the following conditional expression is satisfied.

-1.5 <f _w / EX _w <0 (6)
Where EX _{w is} the exit pupil position measured from the image plane at the wide-angle end,
f _w : focal length of the entire system at the wide-angle end,
It is.

  Hereinafter, the reason and action of the fourth variable magnification optical system having the above configuration will be described.

  In order to realize a compact electronic imaging optical system with a short overall length and a measure against peripheral light quantity deterioration due to shading in a negative / positive / negative variable magnification optical system, it is necessary to appropriately set the exit pupil position of the entire optical system. is there. At this time, by satisfying the conditional expression (6), it is possible to realize an optical system that keeps the tilt angle of off-axis rays as small as possible, does not deteriorate the peripheral light amount due to shading, and maintains good performance. If the upper limit of 0 in conditional expression (6) is exceeded, imaging cannot be performed. If the lower limit of −1.5 of conditional expression (6) is not reached, the exit pupil position moves further to the image plane side, the off-axis principal ray tilt angle increases, and peripheral light quantity deterioration due to shading is caused. In the worst case, imaging cannot be performed.

  Furthermore, when the following conditional expression (6-2) is satisfied, the overall length of the optical system can be reduced while maintaining good performance. If the upper limit of 0 in conditional expression (6-2) is exceeded, the total length of the optical system becomes long. Therefore, it becomes difficult to realize a compact optical system. If the lower limit value of -1.0 of conditional expression (6-2) is not reached, the off-axis principal ray tilt angle becomes remarkably large. Therefore, the peripheral light amount deterioration due to shading is caused.

−1.0 <f _w / EX _w <0 (6-2)
Further, it is preferable that the following conditional expression (6-3) is satisfied. By satisfying this condition, the overall length of the optical system can be reduced while maintaining good performance.

−0.8 <f _w / EX _w <0 (6-3)
The fifth variable power optical system of the present invention is characterized in that, in the first to fourth variable power optical systems, the following conditional expression is satisfied.

2 <f _w / d _w23 <100 (7)
Where f _{w is} the focal length of the entire system at the wide-angle end,
d _w23 : group interval between the second lens unit and the third lens unit at the wide-angle end,
It is.

  Hereinafter, the reason and action of the fifth variable magnification optical system having the above configuration will be described.

  At the wide-angle end, it is preferable to reduce the group interval between the second lens group and the third lens group. By doing in this way, the principal point space | interval of each lens group can be shortened. As a result, the overall length of the optical system can be shortened. Further, by reducing the group interval between the second lens group and the third lens group at the wide angle end, the back focus at the wide angle end can be lengthened. Thereby, the space can be used for installation of a lens group driving mechanism or a shutter. At this time, by satisfying the conditional expression (7), the overall length is short and the back focus can be increased while maintaining the performance. When the upper limit of 100 in conditional expression (7) is exceeded, the distance between the principal points of the second lens group and the third lens group becomes too small. In this case, the first lens group moves from the image side position in the intermediate state to the object side position at the telephoto end. As described above, since the moving amount of the first lens group becomes large, it is difficult to reduce the size. If the lower limit value 2 of conditional expression (7) is not reached, the principal point interval between the second lens group and the third lens group becomes too large. In this case, the imaging position moves further to the image side. For this reason, the first lens group also moves to the image side, and the amount of movement increases. Therefore, downsizing becomes difficult. Further, since the third lens group moves further to the image side, the back focus cannot be secured.

  Furthermore, it is preferable that the following conditional expression (7-2) is satisfied. By satisfying this condition, the back focus can be increased while maintaining good performance.

3 <f _w / d _w23 <50 (7-2)
Furthermore, it is preferable that the following conditional expression (7-3) is satisfied. By satisfying this condition, the back focus can be increased while maintaining good performance.

4 <f _w / d _w23 <40 (7-3)
A sixth variable magnification optical system according to the present invention is characterized in that, in the first to fifth variable magnification optical systems, any two lens groups are constituted by a single lens.

  The seventh variable power optical system of the present invention is characterized in that, in the first to fifth variable power optical systems, all the lens groups are composed of a single lens.

  The eighth variable power optical system of the present invention is characterized in that, in the first to seventh variable power optical systems, the optical total length is fixed at the time of zooming.

  The ninth variable power optical system of the present invention is characterized in that, in the first to eighth variable power optical systems, the negative lens of the first lens group satisfies the following conditional expression.

0 <SF _G1 <2 (8)
Where SF _G1 is the shaping factor of the first lens group and is defined as SF _G1 = (r _G11 + r _G12 ) / (r _G11 −r _G12 )
r _G11 : radius of curvature of the most object side surface of the first lens group,
r _G12 : radius of curvature of the most image-side surface of the first lens group,
It is.

  Hereinafter, the reason and action of the ninth variable power optical system will be described.

  In the first lens group, the lens diameter is larger than those in the second lens group and the third lens group. However, by providing power to the first lens group, the entrance pupil position becomes closer to the object side. In this way, not only the effective lens diameter of the first lens group can be reduced, but also the overall lens length can be reduced. At this time, by satisfying the conditional expression (8), the effective lens diameter can be reduced while maintaining good performance. When the upper limit of 2 in the conditional expression (8) is exceeded, the positive power of the object side surface increases. In this case, since the entrance pupil position is closer to the image side, the effective lens diameter is increased. Therefore, it is not preferable to exceed the upper limit value. If the lower limit of 0 in conditional expression (8) is not reached, the negative power on the object side becomes too strong. In this case, coma aberration generated at the wide-angle end, astigmatism generated at the telephoto end, and the like become large. Therefore, it is not preferable for aberration correction to be below the lower limit. On the other hand, if the value is below the lower limit value, it becomes impossible to suppress fluctuations in distortion over the wide angle end and the telephoto end.

  Furthermore, it is preferable that the following conditional expression (8-2) is satisfied. By satisfying this condition, the effective lens diameter can be reduced while maintaining good performance.

0.1 <SF _G1 <1 (8-2)
Furthermore, it is preferable that the following conditional expression (8-3) is satisfied. By satisfying this condition, the effective lens diameter can be reduced while maintaining good performance.

0.2 <SF _G1 <0.8 (8-3)
According to a tenth variable magnification optical system of the present invention, in the first to ninth variable magnification optical systems, the second lens group satisfies the following conditional expression.

-2 <SF _G2 <0.1 (9)
Where SF _G2 is the shaping factor of the second lens group and is defined as SF _G2 = (r _G21 + r _G22 ) / (r _G21 −r _G22 )
r _G21 : radius of curvature of the surface closest to the object side of the second lens group,
r _G22 : radius of curvature of the most image-side surface of the second lens group,
It is.

  Hereinafter, the reason and operation of the tenth zoom optical system having the above configuration will be described.

  When the second lens group satisfies the conditional expression (9), the positive refractive power of the image side surface can be reduced, which is effective in the following points. (1) Since the principal point position moves toward the first lens group and the distance between the principal points of the first lens group and the second lens group can be shortened, the overall lens length is shortened. (2) Since the magnification of the second lens group can be increased, the amount of movement of the second lens group accompanying zooming can be reduced, leading to a reduction in the overall length.

  If the upper limit of 0.1 in conditional expression (9) is exceeded, the positive refractive power of the surface closest to the image becomes large. In this case, since the magnification of the second lens group becomes small, the zoom ratio becomes small. Alternatively, in order to obtain the same zoom ratio, the amount of movement of the second lens group accompanying zooming becomes large. Below the lower limit of −2, both astigmatism occurring on the most object-side surface and coma occurring on the most image-side surface are both too large. Therefore, many lenses are required for correction. Therefore, it is not preferable to fall below the lower limit.

  Furthermore, it is preferable that the following conditional expression (9-2) is satisfied. Satisfying this condition is more preferable because the optical system can be made compact.

-1 <SF _G2 <0.05 (9-2)
Furthermore, it is preferable that the following conditional expression (9-3) is satisfied. Satisfying this condition is more preferable because the optical system can be made compact.

-0.2 <SF _G2 <0 (9-3)
An eleventh variable magnification optical system according to the present invention is characterized in that, in the first to tenth variable magnification optical systems, at least one negative lens of the third lens group satisfies the following conditional expression: It is.

−0.5 <SF ₃ <4 (10)
Where SF ₃ is the shaping factor of the negative lens of the third lens group, and is defined by SF ₃ = (r ₃₁ + r ₃₂ ) / (r ₃₁ −r ₃₂ )
r ₃₁ : radius of curvature of the object side surface of the negative lens of the third lens group,
r ₃₂ : radius of curvature of the image side surface of the negative lens of the third lens group,
It is.

  Hereinafter, the reason and action of the eleventh variable magnification optical system adopting the above configuration will be described.

  By satisfying conditional expression (10), the principal point position of the negative lens of the third lens group becomes closer to the object side. Thereby, the principal point interval between the second lens group and the third lens group can be shortened. Therefore, the total lens length can be shortened. If the upper limit of 4 in conditional expression (10) is exceeded, variations in various aberrations such as coma generated on the image side surface will increase. Therefore, exceeding the upper limit is not preferable in terms of aberration correction. Below the lower limit of −0.5, the principal point position of the negative lens in the third lens group is located on the image side. In this case, the main point interval between the second lens group and the third lens group becomes long, and the total lens length also increases. Therefore, it is not preferable to fall below the lower limit.

  Furthermore, it is preferable that the following conditional expression (10-2) is satisfied. If this condition is satisfied, the optical system can be made compact.

0 <SF ₃ <2 (10-2)
Furthermore, it is preferable that the following conditional expression (10-3) is satisfied. If this condition is satisfied, the optical system can be made compact.

0.5 <SF ₃ <1.5 (10-3)
According to a twelfth variable magnification optical system of the present invention, in the first to eleventh variable magnification optical systems, the first lens group has at least one cemented lens.

  Hereinafter, the reason and action of the twelfth variable magnification optical system having the above configuration will be described. Since the first lens group includes the cemented lens, the decentration sensitivity can be reduced. Therefore, the assembly of the optical system is facilitated, leading to cost reduction.

  A thirteenth variable magnification optical system according to the present invention is characterized in that, in the first to twelfth variable magnification optical systems, the first lens group has at least one positive lens.

  Hereinafter, the reason and operation of the thirteenth variable magnification optical system will be described. Since the negative lens of the first lens group has a large power, the entrance pupil position becomes closer to the object side. In this case, not only the effective lens diameter can be reduced, but also a compact optical system with a small overall lens length can be realized. However, if the negative lens in the first lens group has a large power, the distortion and the lateral chromatic aberration due to zooming increase accordingly. Therefore, when the first lens group has a positive lens, it is possible to reduce the amount of distortion and lateral chromatic aberration of the first lens group.

  A fourteenth variable magnification optical system according to the present invention is characterized in that, in the thirteenth variable magnification optical system, the positive lens is disposed closest to the image side.

  The reason and action of the above-described configuration in the fourteenth variable magnification optical system will be described below. Since the most image side of the first lens group is a positive lens and the negative lens has a large power, the entrance pupil position becomes closer to the object side. Therefore, the effective lens diameter can be reduced. In addition, a compact optical system with a small overall lens length can be realized. In addition, it is possible to reduce lateral chromatic aberration that is greatly generated in the negative lens of the first lens group. From such a point, it is preferable that the positive lens is disposed on the most image side.

  A fifteenth variable magnification optical system according to the present invention is characterized in that, in the first to fourteenth variable magnification optical systems, the second lens group has at least one cemented lens.

  Hereinafter, the reason and operation of the fifteenth variable magnification optical system will be described. Since the second lens group includes the cemented lens, the decentration sensitivity can be reduced. Therefore, the assembly of the optical system is facilitated and the cost is reduced.

  According to a sixteenth variable magnification optical system of the present invention, in the first to fifteenth variable magnification optical systems, the second lens group has at least one negative lens.

  The reason and action of the above configuration in the sixteenth variable magnification optical system will be described below. Since the positive lens of the second lens group has a large power, the amount of movement of the second lens group associated with zooming is reduced. Therefore, a compact optical system can be realized. However, if the positive lens in the second lens group has a large power, the variation in spherical aberration and axial chromatic aberration associated with zooming increases. Therefore, when the second lens group includes a negative lens, the amount of spherical aberration and axial chromatic aberration of the second lens group can be reduced.

  The seventeenth variable magnification optical system according to the present invention is characterized in that, in the sixteenth variable magnification optical system, the negative lens is disposed closest to the image side.

  Hereinafter, the reason and action of the above-described configuration in the seventeenth variable magnification optical system will be described. By using the negative lens on the most image side of the second lens group, there are the following advantages. (1) Since the principal point position moves toward the first lens group and the distance between the principal points of the first lens group and the second lens group can be shortened, the overall lens length is shortened. (2) Since the magnification of the second lens group can be increased, the amount of movement of the second lens group accompanying zooming can be reduced, leading to a reduction in the overall length.

  According to an eighteenth variable magnification optical system of the present invention, in the first to seventeenth variable magnification optical systems, the negative lens of the first lens group has an aspheric surface on the object side surface. is there.

  The reason and action of the above configuration in the eighteenth variable magnification optical system will be described below. At the wide-angle end, the light ray height at the first lens group is high. Thus, by providing an aspherical surface on the object side of the negative lens, off-axis aberrations such as coma and astigmatism can be favorably corrected. At the telephoto end, the beam diameter in the first lens group is large. Therefore, by providing an aspheric surface on the object side of the negative lens, spherical aberration and the like can be corrected satisfactorily.

  The first lens group has a negative power and has a high ray height. Therefore, negative distortion occurs in the first lens group. At this time, by having an aspheric surface on the object side of the negative lens, it is possible to satisfactorily correct the amount of variation in distortion.

  According to a nineteenth variable magnification optical system of the present invention, in the first to eighteenth variable magnification optical systems, the negative lens of the first lens group has an aspheric surface on the image side surface. is there.

  The reason and action of the above-described configuration in the nineteenth variable magnification optical system will be described below. At the wide-angle end, the light ray height at the first lens group is high. Therefore, by providing an aspherical surface on the image side of the negative lens, off-axis aberrations such as coma and astigmatism can be favorably corrected. At the telephoto end, the beam diameter in the first lens group is large. Therefore, by providing an aspheric surface on the object side of the negative lens, spherical aberration and the like can be corrected satisfactorily.

  According to a twentieth variable magnification optical system of the present invention, in the first to nineteenth variable magnification optical systems, at least one positive lens included in the second lens group has an aspheric surface on the object side. It is what.

  Hereinafter, the reason and action of the twentieth variable magnification optical system having the above configuration will be described. The beam diameter in the second lens group is large. Thus, by providing an aspheric surface on the object side of the positive lens, particularly spherical aberration and the like can be favorably corrected.

  According to a twenty-first variable magnification optical system of the present invention, in the first to twentieth variable magnification optical systems, at least one positive lens included in the second lens group has an aspheric surface on the image side. It is what.

  Hereinafter, the reason and effect of the above-described configuration in the twenty-first variable magnification optical system will be described. Since the positive lens of the second lens group has a large power, the amount of movement of the second lens group becomes small. As a result, a compact optical system can be realized. However, when the positive lens in the second lens group has a large power, coma aberration is greatly generated. Therefore, by providing an aspherical surface on the image side of the positive lens, it is possible to satisfactorily correct coma at the wide angle end.

  Since the light beam diameter in the second lens group is large, it is preferable to have an aspheric surface on the object side of the positive lens so that spherical aberration and the like at the telephoto end can be corrected well.

  According to a twenty-second variable magnification optical system of the present invention, in the first to twenty-first variable magnification optical systems, the negative lens of the first lens group is a lens made of a resin material. is there.

  Hereinafter, the reason and action of the above configuration in the twenty-second variable magnification optical system will be described. Resin material lenses can be manufactured at a lower cost than glass. The same applies to the following twenty-third to twenty-fourth variable power optical systems.

  According to a twenty-third variable power optical system of the present invention, in the first to twenty-second variable power optical system, at least one positive lens included in the second lens group is made of a resin material. To do.

  According to a twenty-fourth variable power optical system of the present invention, in the first to twenty-third variable power optical systems, at least one negative lens of the third lens group is made of a resin material. It is.

  The 25th variable magnification optical system of the present invention is characterized in that, in the 1st to 24th variable magnification optical systems, the negative lens of the first lens group is made of a material satisfying the following conditional expression. Is.

40 <ν _d1 <100 (11)
Where ν _{d1 is} the Abbe number of the negative lens in the first lens group,
It is.

  Hereinafter, the reason and action of the above configuration in the 25th variable magnification optical system will be described.

  Since the first lens group has a negative power, a large lateral chromatic aberration is generated particularly at the wide-angle end. In addition, when the first lens group is composed of one negative lens, it is not possible to suppress the amount of chromatic aberration of magnification by arranging a positive lens in the first lens group. Therefore, it is preferable that the negative lens of the first lens group satisfies the conditional expression (11). By satisfying this condition, the amount of chromatic aberration of magnification can be reduced. If the upper limit of 100 in conditional expression (11) is exceeded, no resource exists. If the lower limit of 40 is not reached, the lateral chromatic aberration generated in the first lens group becomes too large. Therefore, in order to suppress lateral chromatic aberration in the entire system, a large number of lenses are required in other lens groups.

  Furthermore, it is preferable that the following conditional expression (11-2) is satisfied. By satisfying this condition, the amount of chromatic aberration of magnification can be reduced.

50 <ν _d1 <100 (11-2)
Furthermore, it is preferable that the following conditional expression (11-3) is satisfied. By satisfying this condition, the amount of chromatic aberration of magnification can be reduced.

55 <ν _d1 <100 (11-3)
According to a twenty-sixth variable power optical system of the present invention, in the first to twenty-fifth variable power optical systems, the positive lens of the second lens group is made of a material that satisfies the following conditional expression. Is.

40 <ν _d2 <100 (12)
Where ν _{d2 is} the Abbe number of the positive lens in the second lens group,
It is.

  Hereinafter, the reason and operation of the above-described configuration in the twenty-sixth variable magnification optical system will be described.

  Since the positive lens of the second lens group has a large power, the movement amount of the second lens group becomes small. Thereby, a compact optical system can be realized. However, if the positive lens in the second lens group has a large power, the axial chromatic aberration is greatly increased. Therefore, it is preferable that the negative lens of the second lens group satisfies the conditional expression (12). By satisfying this condition, the amount of axial chromatic aberration generated can be reduced. If the upper limit of 100 in conditional expression (12) is exceeded, no resource exists. If the lower limit of 40 is not reached, the longitudinal chromatic aberration generated in the second lens group becomes too large. Therefore, in order to suppress axial chromatic aberration in the entire system, a large number of lenses are required in other lens groups.

  Furthermore, it is preferable that the following conditional expression (12-2) is satisfied. Satisfying this condition is more preferable because the amount of axial chromatic aberration generated can be reduced.

50 <ν _d2 <100 (12-2)
Furthermore, it is preferable that the following conditional expression (12-3) is satisfied. Satisfying this condition is more preferable because the amount of axial chromatic aberration generated can be reduced.

55 <ν _d2 <100 (12-3)
According to a twenty-seventh variable magnification optical system of the present invention, in the first through twenty-sixth variable magnification optical systems, at least one negative lens of the third lens group is made of a material that satisfies the following conditional expression: It is characterized by.

0 <ν _d3 <40 (13)
Where ν _{d3 is} the Abbe number of the negative lens in the third lens group,
It is.

  Hereinafter, the reason and action of the above-described configuration in the 27th variable magnification optical system will be described.

  If the first lens group is composed of one negative lens, the lateral chromatic aberration is greatly generated. In addition, axial chromatic aberration occurs in the second lens group. The third lens group is involved in lateral chromatic aberration correction and axial chromatic aberration correction. Therefore, by satisfying conditional expression (13), it is possible not only to correct lateral chromatic aberration satisfactorily even if the first lens group is composed of one negative lens, but also to improve axial chromatic aberration generated in the second lens group. Can be corrected. When the upper limit of 40 in conditional expression (13) is exceeded, the lateral chromatic aberration generated in the first lens group and the axial chromatic aberration generated in the second lens group cannot be suppressed. Therefore, exceeding the upper limit is not preferable in terms of aberration correction. In particular, if the axial chromatic aberration generated in the second lens group cannot be corrected, the fluctuation of the axial chromatic aberration due to zooming becomes large. In this case, the image quality at the center of the image is greatly degraded. Below the lower limit of 0, there are no resources.

  Furthermore, it is preferable that the following conditional expression (13-2) is satisfied. By satisfying this condition, it is possible to satisfactorily correct chromatic aberration generated in the first lens group and the second lens group.

0 <ν _d3 <35 (13-2)
A twenty-eighth variable magnification optical system according to the present invention is characterized in that, in the first to twenty-seventh variable magnification optical system, the following conditional expression is satisfied.

−30 <DT _min <20 (14)
However, DT _min : Minimum distortion amount [%],
It is.

  The reason and action of the above configuration in the 28th variable magnification optical system will be described below.

When the distortion aberration is electrically corrected, the optical system can have a wide angle of view. In this case, it is preferable to generate a negative distortion at the wide-angle end. At this time, by satisfying conditional expression (14), it is possible to realize a wide angle of view with good image quality when the distortion is electrically corrected. If it exceeds 20% of the upper limit value of conditional expression (14), positive distortion will occur at the wide-angle end. In this case, a wide angle of view cannot be realized even if the distortion aberration is electrically corrected. Below -30% of the lower limit, the enlargement magnification at the outermost periphery of the image increases. Therefore, the image after the distortion aberration is electrically corrected becomes rough. Therefore, it is not preferable to fall below the lower limit. Note that FIGS. 23A to 23D show examples of DT _min . 23A to 23D are aberration diagrams showing distortion aberration.

  Furthermore, it is preferable to satisfy the following conditional expression (14-2). By satisfying this condition, it is possible to widen the angle of view without making the image rough.

−25 <DT _min <0 (14-2)
Furthermore, it is preferable that the following conditional expression (12-3) is satisfied. By satisfying this condition, it is possible to widen the angle of view without making the image rough.

−15 <DT _min <−5 (14-3)
The twenty-ninth variable magnification optical system of the present invention is characterized in that, in the first through twenty-eighth variable magnification optical systems, distortion aberration generated in the optical system is electrically corrected.

  The reason and action of the above-described configuration in the 29th variable magnification optical system will be described below.

  If the distortion is to be corrected well by the optical system, the number of lenses increases and the optical system becomes larger. Therefore, it is preferable to electrically correct distortion that cannot be corrected by the optical system. By doing in this way, an optical system can be made more compact.

  Since the retro focus type has a large negative distortion at the wide-angle end, it is easy to increase the angle of view and increase the magnification when electrically correcting the image distortion. Therefore, the optical system is preferably a retrofocus type.

  The 30th zoom optical system of the present invention is characterized in that in the first to 29th zoom optical systems, lateral chromatic aberration generated in the optical system is electrically corrected.

  The reason and action of the above configuration in the 30th variable magnification optical system will be described below.

  When the first lens group is composed of one negative lens, lateral chromatic aberration is greatly generated at the wide angle end. Here, if it is intended to satisfactorily correct lateral chromatic aberration with the optical system, the number of lenses increases and the optical system becomes larger. Therefore, it is preferable to electrically correct lateral chromatic aberration that cannot be corrected by the optical system. By doing in this way, an optical system can be made more compact. In correcting the lateral chromatic aberration, electrical distortion distortion is corrected for each color (R / G / B). Here, each color is corrected so as to correspond to the paraxial magnification of the optical system (R → R ′ / G → G ′ / B → B ′). Thereafter, the corrected colors (R ′ / G ′ / B ′) are overlaid again.

  A thirty-first variable power optical system of the present invention is characterized in that, in the first to thirtyth variable power optical systems, an organic-inorganic composite material is used as an optical material of at least one optical element constituting the optical system. It is.

  The reason and action of the above-described configuration in the thirty-first variable magnification optical system will be described below.

  When an organic-inorganic composite material is used as the optical material of the optical element, various optical properties (refractive index, wavelength dispersion) are exhibited depending on the type and abundance ratio of the organic component and the inorganic component (obtained). ). Therefore, by blending the organic component and the inorganic component in an arbitrary ratio, various optical characteristics can be obtained, and various aberrations can be corrected with a smaller number of sheets, that is, at a low cost and a small size.

  A thirty-second variable power optical system of the present invention is the thirty-first variable power optical system, wherein the organic-inorganic composite includes zirconia nanoparticles.

  A thirty-third variable power optical system of the present invention is the thirty-first variable power optical system, wherein the organic-inorganic composite includes zirconia and alumina nanoparticles.

  A thirty-fourth magnification optical system of the present invention is the thirty-first variable magnification optical system, wherein the organic-inorganic composite includes niobium oxide nanoparticles.

  A thirty-fifth variable power optical system of the present invention is the thirty-first variable power optical system, wherein the organic-inorganic composite includes a hydrolyzate of zirconium alkoxide and alumina nanoparticles.

  In the thirty-second to thirty-fifth variable power optical systems of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. The nanoparticles of these materials are examples of inorganic components. Then, by dispersing such nanoparticles in an organic component plastic at a predetermined abundance ratio, various optical characteristics (refractive index, wavelength dispersibility) can be expressed.

  The electronic apparatus of the present invention is characterized by having first to thirty-fifth variable power optical systems and an electronic imaging device arranged on the image side thereof.

  The reason why the above-described configuration is adopted in the electronic apparatus of the present invention and the operation thereof will be described. The above variable magnification optical system of the present invention is small and low-cost. Therefore, in an electronic device equipped with such a variable magnification optical system as an imaging optical system, it is possible to reduce the size and cost of the device. Electronic devices include digital cameras, video cameras, digital video units, personal computers, mobile computers, mobile phones, portable information terminals, and the like.

  According to the present invention, it is possible to obtain a variable magnification optical system that sufficiently corrects axial chromatic aberration with a small number of lenses, and that can effectively achieve both cost reduction and downsizing. Similarly, in the electronic apparatus, the longitudinal chromatic aberration is sufficiently corrected, and it is possible to effectively achieve both cost reduction and size reduction.

  Examples 1 to 11 of the variable magnification optical system (zoom lens) of the present invention will be described below with reference to the drawings. FIGS. 1 to 11 show lens cross-sectional views along the optical axes of the wide-angle end (a), the intermediate state (b), and the telephoto end (c) when focusing on an object point at infinity in Examples 1 to 11, respectively. In each figure, G1 is a first lens group, G2 is a second lens group, G3 is a third lens group, S is an aperture stop, F is a near-infrared cut filter, a low-pass filter, a parallel glass such as a cover glass of an electronic image sensor, and the like. A plane plate group, I represents an image plane. In addition, the spherical aberration, astigmatism, chromaticity of magnification (aberration), and distortion of the wide-angle end (a), the intermediate state (b), and the telephoto end (c) at the time of focusing on an object point at infinity in Examples 1 to 11 Aberration diagrams are shown in FIGS. In these aberration diagrams, “FIY” represents the image height.

  As shown in FIG. 1, the variable magnification optical system of the first embodiment includes a first lens group G1, an aperture stop S, a second lens group G2, and a third lens group G3 in order from the object side. ing. When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves monotonously with the aperture stop S toward the object side, and the third lens group G3 is the second lens group G3. It moves to the object side so that the distance from the lens group G2 is once narrowed and then widened.

  The first lens group G1 is composed of a biconcave negative lens and has negative power. Both surfaces of this biconcave negative lens are aspheric.

  The second lens group G2 is composed of a biconvex positive lens and has positive power. Both surfaces of this biconvex positive lens are aspheric.

  The third lens group G3 is composed of a biconcave negative lens and has negative power. The image side surface of this biconcave negative lens is aspheric.

  All the lenses in this embodiment are made of a resin material.

  As shown in FIG. 2, the variable magnification optical system of the second embodiment includes, in order from the object side, a first lens group G1, an aperture stop S, a second lens group G2, and a third lens group G3. ing. When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves monotonously with the aperture stop S toward the object side, and the third lens group G3 is the second lens group G3. It moves to the object side so that the distance from the lens group G2 is once narrowed and then widened.

  The first lens group G1 is composed of a biconcave negative lens and has negative power. Both surfaces of this biconcave negative lens are aspheric.

  The second lens group G2 is composed of a biconvex positive lens and has positive power. Both surfaces of this biconvex positive lens are aspheric.

  The third lens group G3 is composed of a biconcave negative lens and has negative power. The image side surface of this biconcave negative lens is aspheric.

  All the lenses in this embodiment are made of a resin material.

  As shown in FIG. 3, the zoom optical system of Example 3 includes, in order from the object side, a first lens group G1, an aperture stop S, a second lens group G2, and a third lens group G3. ing. When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves monotonously with the aperture stop S toward the object side, and the third lens group G3 is the second lens group G3. It moves to the object side so that the distance from the lens group G2 is once narrowed and then widened.

  The first lens group G1 is composed of a biconcave negative lens and has negative power. Both surfaces of this biconcave negative lens are aspheric.

  The second lens group G2 is composed of a biconvex positive lens and has positive power. Both surfaces of this biconvex positive lens are aspheric.

  The third lens group G3 is composed of a biconcave negative lens and has negative power. The image side surface of this biconcave negative lens is aspheric.

  The lenses of this example are all made of a resin material except that the biconcave negative lens of the first lens group G1 is made of glass.

  As shown in FIG. 4, the zoom optical system of Example 4 includes, in order from the object side, a first lens group G1, an aperture stop S, a second lens group G2, and a third lens group G3. ing. When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves monotonously with the aperture stop S toward the object side, and the third lens group G3 is the second lens group G3. It moves to the object side so that the distance from the lens group G2 is once narrowed and then widened.

  The first lens group G1 is composed of a biconcave negative lens and has negative power. Both surfaces of this biconcave negative lens are aspheric.

  The second lens group G2 is composed of a biconvex positive lens and has positive power. Both surfaces of this biconvex positive lens are aspheric.

  The third lens group G3 is composed of a biconcave negative lens and has negative power. The image side surface of this biconcave negative lens is aspheric.

  The lenses of this example are all made of a resin material except that the biconcave negative lens of the first lens group G1 is made of glass.

  As shown in FIG. 5, the variable magnification optical system of Example 5 includes, in order from the object side, a first lens group G1, an aperture stop S, a second lens group G2, and a third lens group G3. ing. When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves monotonously with the aperture stop S toward the object side, and the third lens group G3 is the second lens group G3. It moves to the object side so that the distance from the lens group G2 is once narrowed and then widened.

  The first lens group G1 is composed of a biconcave negative lens and has negative power. Both surfaces of this biconcave negative lens are aspheric.

  The second lens group G2 is composed of a biconvex positive lens and has positive power. Both surfaces of this biconvex positive lens are aspheric.

  The third lens group G3 includes a negative meniscus lens having a convex surface directed toward the object side, and has negative power. The image side surface of the negative meniscus lens is aspheric.

  The lenses of this example are all made of a resin material except that the biconvex positive lens of the second lens group G2 is made of glass.

  As shown in FIG. 6, the variable magnification optical system of the sixth embodiment includes, in order from the object side, a first lens group G1, an aperture stop S, a second lens group G2, and a third lens group G3. ing. When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves monotonously with the aperture stop S toward the object side, and the third lens group G3 is the second lens group G3. It moves to the object side so that the distance from the lens group G2 is once narrowed and then widened.

  The first lens group G1 is composed of a biconcave negative lens and has negative power. Both surfaces of this biconcave negative lens are aspheric.

  The second lens group G2 is composed of a biconvex positive lens and has positive power. Both surfaces of this biconvex positive lens are aspheric.

  The third lens group G3 is composed of a biconcave negative lens and has negative power. The image side surface of this biconcave negative lens is aspheric.

  The lens of the present embodiment is all made of glass except that the biconcave negative lens of the third lens group G3 is made of a resin material.

  As shown in FIG. 7, the variable magnification optical system of the seventh embodiment includes, in order from the object side, a first lens group G1, an aperture stop S, a second lens group G2, and a third lens group G3. ing. When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves monotonously with the aperture stop S toward the object side, and the third lens group G3 is the second lens group G3. It moves to the object side so that the distance from the lens group G2 is once narrowed and then widened.

  The first lens group G1 includes a cemented lens of a biconcave negative lens and a positive meniscus lens having a convex surface directed toward the object side, and has negative power. The most object side surface of this cemented lens is an aspherical surface.

  The second lens group G2 is composed of a biconvex positive lens and has positive power. Both surfaces of this biconvex positive lens are aspheric.

  The third lens group G3 includes a negative meniscus lens having a convex surface directed toward the object side, and has negative power. The image side surface of the negative meniscus lens is aspheric.

  The lenses of this example are all made of a resin material except that the cemented lens of the first lens group G1 is made of glass.

  As shown in FIG. 8, the variable magnification optical system of the eighth embodiment includes, in order from the object side, a first lens group G1, an aperture stop S, a second lens group G2, and a third lens group G3. ing. When zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves monotonously with the aperture stop S toward the object side, and the third lens group G3 is the second lens group G3. It moves to the object side so that the distance from the lens group G2 is once narrowed and then widened.

  The first lens group G1 is composed of a biconcave negative lens and has negative power. Both surfaces of this biconcave negative lens are aspheric.

  The second lens group G2 includes a cemented lens of a biconvex positive lens and a negative meniscus lens having a convex surface directed toward the image side, and has positive power. The most object side surface and the most image side surface of this cemented lens are aspherical.

  The third lens group G3 includes a negative meniscus lens having a convex surface directed toward the object side, and has negative power. The image side surface of the negative meniscus lens is aspheric.

  The lenses of this example are all made of a resin material except that the cemented lens of the second lens group G2 is made of glass.

  As shown in FIG. 9, the variable magnification optical system according to the ninth embodiment includes, in order from the object side, a first lens group G1, an aperture stop S, a second lens group G2, and a third lens group G3. ing. When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves to the image side, the second lens group G2 moves monotonously to the object side together with the aperture stop S, and the third lens group G3 It moves to the object side while widening the distance from the second lens group G2.

  The first lens group G1 is composed of a biconcave negative lens and has negative power. Both surfaces of this biconcave negative lens are aspheric.

  The second lens group G2 is composed of a biconvex positive lens and has positive power. Both surfaces of this biconvex positive lens are aspheric.

  The third lens group G3 is composed of a biconcave negative lens and has negative power. The image side surface of this biconcave negative lens is aspheric.

  All the lenses in this embodiment are made of a resin material.

  As shown in FIG. 10, the zoom optical system of Example 10 includes, in order from the object side, a first lens group G1, an aperture stop S, a second lens group G2, and a third lens group G3. ing. When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves along a concave locus toward the object side, and at the telephoto end is positioned closer to the image side than the wide-angle end, and the second lens group G2 Moves monotonously with the aperture stop S toward the object side, and the third lens group G3 moves toward the object side while increasing the distance from the second lens group G2.

  The first lens group G1 is composed of a biconcave negative lens and has negative power. Both surfaces of this biconcave negative lens are aspheric.

  The second lens group G2 is composed of a biconvex positive lens and has positive power. Both surfaces of this biconvex positive lens are aspheric.

  The third lens group G3 is composed of a biconcave negative lens and has negative power. The image side surface of this biconcave negative lens is aspheric.

  The lens of the present embodiment is all made of glass except that the biconcave negative lens of the third lens group G3 is made of a resin material.

  As shown in FIG. 11, the variable magnification optical system of the eleventh embodiment includes, in order from the object side, a first lens group G1, an aperture stop S, a second lens group G2, and a third lens group G3. ing. When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves to the image side, the second lens group G2 moves monotonously to the object side together with the aperture stop S, and the third lens group G3 It moves to the object side while widening the distance from the second lens group G2.

  The first lens group G1 is composed of a biconcave negative lens and has negative power. Both surfaces of this biconcave negative lens are aspheric.

  The second lens group G2 is composed of a biconvex positive lens and has positive power. Both surfaces of this biconvex positive lens are aspheric.

  The third lens group G3 is composed of a biconcave negative lens and has negative power. The image side surface of this biconcave negative lens is aspheric.

  The lenses of this example are all made of a resin material except that the biconcave negative lens of the first lens group G1 is made of glass.

The numerical data of each of the above embodiments are shown below. Symbols are the above, f is the total focal length, _FNO is the F number, ω is the half angle of view, WE is the wide angle end, ST is the intermediate state, TE telephoto end, r _1, r ₂ ... curvature radius of each lens surface, d _1, d ₂ ... the spacing between the lens surfaces, n _d1, n _d2 ... d-line refractive index of each lens, [nu _d1 , Ν _d2 ... Is the Abbe number of each lens. The aspherical shape is represented by the following formula, where x is an optical axis with the light traveling direction being positive, and y is a direction orthogonal to the optical axis.

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

Example 1
r ₁ = -13.301 (aspherical surface) d ₁ = 0.50 n _d1 = 1.52542 ν _d1 = 55.78
r ₂ = 4.400 (aspherical surface) d ₂ = (variable)
r ₃ = ∞ (aperture) d ₃ = -0.21
r ₄ = 2.523 (aspherical surface) d ₄ = 1.46 n _d2 = 1.52542 ν _d2 = 55.78
r ₅ = -2.766 (aspherical surface) d ₅ = (variable)
r ₆ = -36.649 d ₆ = 1.44 n _d3 = 1.60687 ν _d3 = 27.03
r ₇ = 3.000 (aspherical surface) d ₇ = (variable)
r ₈ = ∞ d ₈ = 0.50 n _d4 = 1.51633 ν _d4 = 64.14
r ₉ = ∞ d ₉ = 0.50
r ₁₀ = ∞ (image plane)
Aspheric coefficient 1st surface K = 30.659
A ₄ = -2.36574 × 10 ^-2
A ₆ = 3.33573 × 10 ^-3
A ₈ = 6.22980 × 10 ^-5
Second side K = 3.550
A ₄ = -3.27459 × 10 ^-2
A ₆ = 2.24325 × 10 ^-3
A ₈ = 3.25139 × 10 ^-4
4th surface K = -1.263
A ₄ = 4.34987 × 10 ^-4
A ₆ = 3.33553 × 10 ^-4
A ₈ = 0
Fifth side K = -0.008
A ₄ = 2.35924 × 10 ^-2
A ₆ = -1.86546 × 10 ^-3
A ₈ = 1.45860 × 10 ^-4
Surface 7 K = -6.909
A ₄ = 2.03999 × 10 ^-2
A ₆ = 1.11090 × 10 ^-4
A ₈ = 1.03585 × 10 ^-3
Zoom data (∞)
WE ST TE
f (mm) 3.950 6.432 10.824
F _NO 2.80 3.74 4.91
ω (°) 37.3 ° 20.0 ° 11.5 °
d ₂ 4.24 2.35 0.41
d ₅ 0.30 0.10 0.41
d ₇ 2.89 4.97 6.60.

Example 2
r ₁ = -11.940 (aspherical surface) d ₁ = 0.50 n _d1 = 1.52542 ν _d1 = 55.78
r ₂ = 3.659 (aspherical surface) d ₂ = (variable)
r ₃ = ∞ (aperture) d ₃ = -0.10
r ₄ = 2.062 (aspherical surface) d ₄ = 1.19 n _d2 = 1.52542 ν _d2 = 55.78
r ₅ = -2.199 (aspherical surface) d ₅ = (variable)
r ₆ = -38.737 d ₆ = 0.54 n _d3 = 1.60687 ν _d3 = 27.03
r ₇ = 2.905 (aspherical surface) d ₇ = (variable)
r ₈ = ∞ d ₈ = 0.50 n _d4 = 1.51633 ν _d4 = 64.14
r ₉ = ∞ d ₉ = 0.50
r ₁₀ = ∞ (image plane)
Aspheric coefficient 1st surface K = 31.941
A ₄ = -4.17070 × 10 ^-2
A ₆ = 9.14309 × 10 ^-3
A ₈ = -1.31968 × 10 ^-4
Second side K = 3.550
A ₄ = -5.70117 × 10 ^-2
A ₆ = 6.43629 × 10 ^-3
A ₈ = 9.83126 × 10 ^-4
4th surface K = -1.133
A ₄ = 1.65558 × 10 ^-3
A ₆ = -7.70764 × 10 ^-4
A ₈ = 0
Fifth side K = -0.008
A ₄ = 6.08676 × 10 ^-2
A ₆ = -2.03279 × 10 ^-2
A ₈ = 4.99990 × 10 ^-3
Surface 7 K = -5.725
A ₄ = -1.30052 × 10 ^-3
A ₆ = 2.35060 × 10 ^-2
A ₈ = -4.25572 × 10 ^-3
Zoom data (∞)
WE ST TE
f (mm) 3.922 5.275 7.264
F _NO 2.80 3.30 3.88
ω (°) 36.5 ° 24.6 ° 17.2 °
d ₂ 2.46 1.48 0.46
d ₅ 0.17 0.10 0.20
d ₇ 3.36 4.42 5.34.

Example 3
r ₁ = -12.359 (aspherical surface) d ₁ = 0.50 n _d1 = 1.51633 ν _d1 = 64.14
r ₂ = 4.273 (aspherical surface) d ₂ = (variable)
r ₃ = ∞ (aperture) d ₃ = 0.00
r ₄ = 2.363 (aspherical surface) d ₄ = 1.41 n _d2 = 1.52542 ν _d2 = 55.78
r ₅ = -2.625 (aspherical surface) d ₅ = (variable)
r ₆ = -21.747 d ₆ = 1.15 n _d3 = 1.60687 ν _d3 = 27.03
r ₇ = 2.900 (aspherical surface) d ₇ = (variable)
r ₈ = ∞ d ₈ = 0.50 n _d4 = 1.51633 ν _d4 = 64.14
r ₉ = ∞ d ₉ = 0.50
r ₁₀ = ∞ (image plane)
Aspheric coefficient 1st surface K = 24.290
A ₄ = -2.58551 × 10 ^-2
A ₆ = 4.45126 × 10 ^-3
A ₈ = -7.50194 × 10 ^-5
Second side K = 3.550
A ₄ = -3.60501 × 10 ^-2
A ₆ = 3.83461 × 10 ^-3
A ₈ = 2.98195 × 10 ^-5
4th surface K = -1.165
A ₄ = 1.12396 × 10 ^-3
A ₆ = 3.67043 × 10 ^-4
A ₈ = 0
Fifth side K = -0.008
A ₄ = 3.11728 × 10 ^-2
A ₆ = -4.35809 × 10 ^-3
A ₈ = 6.90961 × 10 ^-4
Surface 7 K = -7.130
A ₄ = 2.15650 × 10 ^-2
A ₆ = 1.31382 × 10 ^-3
A ₈ = 1.24153 × 10 ^-3
Zoom data (∞)
WE ST TE
f (mm) 3.958 6.399 10.828
F _NO 2.82 3.76 4.94
ω (°) 37.3 ° 20.1 ° 11.5 °
d ₂ 4.03 2.15 0.20
d ₅ 0.24 0.10 0.38
d ₇ 3.20 5.21 6.88.

Example 4
r ₁ = -11.359 (aspherical surface) d ₁ = 0.50 n _d1 = 1.49700 ν _d1 = 81.54
r ₂ = 4.318 (aspherical surface) d ₂ = (variable)
r ₃ = ∞ (aperture) d ₃ = 0.00
r ₄ = 2.309 (aspherical surface) d ₄ = 1.49 n _d2 = 1.52542 ν _d2 = 55.78
r ₅ = -2.507 (aspherical surface) d ₅ = (variable)
r ₆ = -13.699 d ₆ = 1.05 n _d3 = 1.60687 ν _d3 = 27.03
r ₇ = 2.907 (aspherical surface) d ₇ = (variable)
r ₈ = ∞ d ₈ = 0.50 n _d4 = 1.51633 ν _d4 = 64.14
r ₉ = ∞ d ₉ = 0.50
r ₁₀ = ∞ (image plane)
Aspheric coefficient 1st surface K = 20.186
A ₄ = -2.51615 × 10 ^-2
A ₆ = 4.56174 × 10 ^-3
A ₈ = -1.00230 × 10 ^-4
Second side K = 3.550
A ₄ = -3.51804 × 10 ^-2
A ₆ = 3.82751 × 10 ^-3
A ₈ = 8.14818 × 10 ^-5
4th surface K = -1.204
A ₄ = 2.20390 × 10 ^-3
A ₆ = 6.44510 × 10 ^-4
A ₈ = 0
Fifth side K = -0.008
A ₄ = 3.62528 × 10 ^-2
A ₆ = -5.04860 × 10 ^-3
A ₈ = 8.37603 × 10 ^-4
Surface 7 K = -6.547
A ₄ = 1.56213 × 10 ^-2
A ₆ = 3.15669 × 10 ^-3
A ₈ = 1.36558 × 10 ^-3
Zoom data (∞)
WE ST TE
f (mm) 3.959 6.401 10.845
F _NO 2.80 3.73 4.91
ω (°) 37.3 ° 20.1 ° 11.6 °
d ₂ 4.09 2.20 0.20
d ₅ 0.24 0.10 0.33
d ₇ 3.19 5.23 6.99.

Example 5
r ₁ = -21.429 (aspherical surface) d ₁ = 0.50 n _d1 = 1.52542 ν _d1 = 55.78
r ₂ = 4.619 (aspherical surface) d ₂ = (variable)
r ₃ = ∞ (aperture) d ₃ = -0.17
r ₄ = 2.659 (aspherical surface) d ₄ = 0.86 n _d2 = 1.51633 ν _d2 = 64.14
r ₅ = -3.624 (aspherical surface) d ₅ = (variable)
r ₆ = 6.782 d ₆ = 0.91 n _d3 = 1.60687 ν _d3 = 27.03
r ₇ = 2.382 (aspherical surface) d ₇ = (variable)
r ₈ = ∞ d ₈ = 0.50 n _d4 = 1.51633 ν _d4 = 64.14
r ₉ = ∞ d ₉ = 0.50
r ₁₀ = ∞ (image plane)
Aspheric coefficient 1st surface K = 71.039
A ₄ = -2.47880 × 10 ^-2
A ₆ = 2.64856 × 10 ^-3
A ₈ = 3.65012 × 10 ^-5
Second side K = 3.550
A ₄ = -3.24371 × 10 ^-2
A ₆ = 2.77916 × 10 ^-3
A ₈ = -6.03364 × 10 ^-5
4th surface K = -1.213
A ₄ = 1.70119 × 10 ^-4
A ₆ = -6.82666 × 10 ^-4
A ₈ = 0
Fifth side K = -0.008
A ₄ = 1.39609 × 10 ^-2
A ₆ = -2.94335 × 10 ^-3
A ₈ = 4.04123 × 10 ^-4
Surface 7 K = -4.436
A ₄ = 3.55598 × 10 ^-2
A ₆ = -3.38725 × 10 ^-3
A ₈ = 1.33223 × 10 ^-3
Zoom data (∞)
WE ST TE
f (mm) 3.967 6.408 10.820
F _NO 2.80 3.76 4.97
ω (°) 38.3 ° 20.2 ° 11.6 °
d ₂ 4.53 2.53 0.37
d ₅ 0.60 0.10 0.35
d ₇ 3.09 5.59 7.51.

Example 6
r ₁ = -16.166 (aspherical surface) d ₁ = 0.50 n _d1 = 1.51633 ν _d1 = 64.14
r ₂ = 4.281 (aspherical surface) d ₂ = (variable)
r ₃ = ∞ (aperture) d ₃ = 0.00
r ₄ = 2.401 (aspherical surface) d ₄ = 1.31 n _d2 = 1.58313 ν _d2 = 59.38
r ₅ = -2.750 (aspherical surface) d ₅ = (variable)
r ₆ = -16.526 d ₆ = 0.87 n _d3 = 1.58393 ν _d3 = 30.21
r ₇ = 2.381 (aspherical surface) d ₇ = (variable)
r ₈ = ∞ d ₈ = 0.50 n _d4 = 1.51633 ν _d4 = 64.14
r ₉ = ∞ d ₉ = 0.50
r ₁₀ = ∞ (image plane)
Aspheric coefficient 1st surface K = 44.701
A ₄ = -2.57066 × 10 ^-2
A ₆ = 3.64384 × 10 ^-3
A ₈ = 2.10394 × 10 ^-5
Second side K = 3.550
A ₄ = -3.59492 × 10 ^-2
A ₆ = 3.38526 × 10 ^-3
A ₈ = 2.76185 × 10 ^-5
4th surface K = -1.106
A ₄ = 1.75561 × 10 ^-3
A ₆ = 4.63566 × 10 ^-4
A ₈ = 0
Fifth side K = -0.008
A ₄ = 3.48039 × 10 ^-2
A ₆ = -6.50998 × 10 ^-3
A ₈ = 1.12415 × 10 ^-3
Surface 7 K = -3.932
A ₄ = 1.43665 × 10 ^-2
A ₆ = 7.11486 × 10 ^-3
A ₈ = 6.28436 × 10 ^-4
Zoom data (∞)
WE ST TE
f (mm) 3.943 6.389 10.810
F _NO 2.80 3.75 4.95
ω (°) 37.4 ° 20.1 ° 11.5 °
d ₂ 4.13 2.23 0.20
d ₅ 0.25 0.10 0.27
d ₇ 3.20 5.25 7.11.

Example 7
r ₁ = -4.240 (aspherical surface) d ₁ = 0.50 n _d1 = 1.49700 ν _d1 = 81.54
r ₂ = 7.703 d ₂ = 0.50 n _d2 = 1.68893 ν _d2 = 31.07
r ₃ = 9.228 d ₃ = (variable)
r ₄ = ∞ (aperture) d ₄ = -0.00
r ₅ = 2.635 (aspherical surface) d ₅ = 1.35 n _d3 = 1.49700 ν _d3 = 81.54
r ₆ = -3.396 (aspherical surface) d ₆ = (variable)
r ₇ = 11.260 d ₇ = 1.62 n _d4 = 1.60687 ν _d4 = 27.03
r ₈ = 2.721 (aspherical surface) d ₈ = (variable)
r ₉ = ∞ d ₉ = 0.50 n _d5 = 1.51633 ν _d5 = 64.14
r ₁₀ = ∞ d ₁₀ = 0.50
r ₁₁ = ∞ (image plane)
Aspheric coefficient 1st surface K = 1.408
A ₄ = 4.60087 × 10 ^-3
A ₆ = -3.30069 × 10 ^-4
A ₈ = 1.11194 × 10 ^-4
Fifth side K = -1.457
A ₄ = 8.10700 × 10 ^-4
A ₆ = -9.63678 × 10 ^-4
A ₈ = 0
6th surface K = -0.008
A ₄ = 1.29509 × 10 ^-2
A ₆ = -2.90068 × 10 ^-3
A ₈ = 3.72722 × 10 ^-4
Surface 8 K = -2.296
A ₄ = 1.03930 × 10 ^-2
A ₆ = 5.69413 × 10 ^-3
A ₈ = -3.99597 × 10 ^-4
Zoom data (∞)
WE ST TE
f (mm) 3.936 6.382 10.811
F _NO 2.80 3.71 4.82
ω (°) 37.3 ° 20.1 ° 11.5 °
d ₃ 4.05 2.15 0.20
d ₆ 0.34 0.10 0.78
d ₈ 3.07 5.20 6.47

Example 8
r ₁ = -11.926 (aspherical surface) d ₁ = 0.50 n _d1 = 1.52542 ν _d1 = 55.78
r ₂ = 4.279 (aspherical surface) d ₂ = (variable)
r ₃ = ∞ (aperture) d ₃ = 0.00
r ₄ = 2.746 (aspherical surface) d ₄ = 1.02 n _d2 = 1.58313 ν _d2 = 59.38
r ₅ = -3.322 d ₅ = 0.50 n _d3 = 1.68893 ν _d3 = 31.07
r ₆ = -3.314 (aspherical surface) d ₆ = (variable)
r ₇ = 399.975 d ₇ = 0.63 n _d4 = 1.60687 ν _d4 = 27.03
r ₈ = 2.967 (aspherical surface) d ₈ = (variable)
r ₉ = ∞ d ₉ = 0.50 n _d5 = 1.51633 ν _d5 = 64.14
r ₁₀ = ∞ d ₁₀ = 0.50
r ₁₁ = ∞ (image plane)
Aspheric coefficient 1st surface K = 23.056
A ₄ = -2.42610 × 10 ^-2
A ₆ = 3.56874 × 10 ^-3
A ₈ = 3.68044 × 10 ^-5
Second side K = 3.550
A ₄ = -3.39205 × 10 ^-2
A ₆ = 2.64970 × 10 ^-3
A ₈ = 1.50451 × 10 ^-4
4th surface K = -1.232
A ₄ = -4.75437 × 10 ^-4
A ₆ = -3.98067 × 10 ^-4
A ₈ = 0
6th surface K = -0.008
A ₄ = 1.27728 × 10 ^-2
A ₆ = -1.56287 × 10 ^-3
A ₈ = 6.74746 × 10 ^-5
Surface 8 K = -3.972
A ₄ = 1.29056 × 10 ^-2
A ₆ = 3.98154 × 10 ^-3
A ₈ = -3.71924 × 10 ^-5
Zoom data (∞)
WE ST TE
f (mm) 3.959 6.390 10.807
F _NO 2.80 3.69 4.78
ω (°) 37.3 ° 20.1 ° 11.5 °
d ₂ 3.96 2.11 0.20
d ₆ 0.75 0.59 1.01
d ₈ 3.09 5.10 6.59

Example 9
r ₁ = -11.071 (aspherical surface) d ₁ = 0.50 n _d1 = 1.52542 ν _d1 = 55.78
r ₂ = 5.692 (aspherical surface) d ₂ = (variable)
r ₃ = ∞ (aperture) d ₃ = -0.30
r ₄ = 2.338 (aspherical surface) d ₄ = 1.02 n _d2 = 1.52542 ν _d2 = 55.78
r ₅ = -3.435 (aspherical surface) d ₅ = (variable)
r ₆ = -26.004 d ₆ = 1.20 n _d3 = 1.60687 ν _d3 = 27.03
r ₇ = 3.254 (aspherical surface) d ₇ = (variable)
r ₈ = ∞ d ₈ = 0.50 n _d4 = 1.51633 ν _d4 = 64.14
r ₉ = ∞ d ₉ = 0.50
r ₁₀ = ∞ (image plane)
Aspheric coefficient 1st surface K = 6.299
A ₄ = -1.57475 × 10 ^-2
A ₆ = 3.01261 × 10 ^-3
A ₈ = -1.59459 × 10 ^-4
Second side K = -10.261
A ₄ = -9.23389 × 10 ^-3
A ₆ = 2.30799 × 10 ^-3
A ₈ = 5.05593 × 10 ^-5
4th surface K = -0.954
A ₄ = 3.01739 × 10 ^-3
A ₆ = 1.38531 × 10 ^-4
A ₈ = 0
Fifth side K = -0.008
A ₄ = 1.79088 × 10 ^-2
A ₆ = -2.28463 × 10 ^-3
A ₈ = 2.74874 × 10 ^-4
Surface 7 K = -3.311
A ₄ = 1.40943 × 10 ^-2
A ₆ = 6.77621 × 10 ^-3
A ₈ = 6.58700 × 10 ^-4
Zoom data (∞)
WE ST TE
f (mm) 3.988 6.389 10.825
F _NO 2.80 3.46 4.54
ω (°) 37.0 ° 20.0 ° 11.5 °
d ₂ 5.67 2.71 0.50
d ₅ 0.18 0.25 0.47
d ₇ 3.78 5.01 6.79.

Example 10
r ₁ = -10.612 (aspherical surface) d ₁ = 0.50 n _d1 = 1.51633 ν _d1 = 64.14
r ₂ = 5.180 (aspherical surface) d ₂ = (variable)
r ₃ = ∞ (aperture) d ₃ = -0.29
r ₄ = 2.333 (aspherical surface) d ₄ = 1.03 n _d2 = 1.58313 ν _d2 = 59.38
r ₅ = -3.057 (aspherical surface) d ₅ = (variable)
r ₆ = -7.903 d ₆ = 1.23 n _d3 = 1.58393 ν _d3 = 30.21
r ₇ = 3.016 (aspherical surface) d ₇ = (variable)
r ₈ = ∞ d ₈ = 0.50 n _d4 = 1.51633 ν _d4 = 64.14
r ₉ = ∞ d ₉ = 0.50
r ₁₀ = ∞ (image plane)
Aspheric coefficient 1st surface K = -5.421
A ₄ = -2.12750 × 10 ^-2
A ₆ = 4.14845 × 10 ^-3
A ₈ = -2.47041 × 10 ^-4
Second side K = 3.550
A ₄ = -2.37739 × 10 ^-2
A ₆ = 3.90946 × 10 ^-3
A ₈ = -7.63720 × 10 ^-5
4th surface K = -0.884
A ₄ = 3.89839 × 10 ^-3
A ₆ = 3.88143 × 10 ^-4
A ₈ = 0
Fifth side K = -0.008
A ₄ = 2.44916 × 10 ^-2
A ₆ = -3.28101 × 10 ^-3
A ₈ = 4.24964 × 10 ^-4
Surface 7 K = -2.782
A ₄ = 1.02944 × 10 ^-2
A ₆ = 1.02246 × 10 ^-2
A ₈ = 9.57636 × 10 ^-4
Zoom data (∞)
WE ST TE
f (mm) 3.979 6.379 10.816
F _NO 2.80 3.50 4.66
ω (°) 37.0 ° 20.0 ° 11.5 °
d ₂ 5.10 2.46 0.49
d ₅ 0.10 0.13 0.26
d ₇ 3.65 4.95 6.95.

Example 11
r ₁ = -9.569 (aspherical surface) d ₁ = 0.50 n _d1 = 1.49700 ν _d1 = 81.54
r ₂ = 5.763 (aspherical surface) d ₂ = (variable)
r ₃ = ∞ (aperture) d ₃ = -0.30
r ₄ = 2.287 (aspherical surface) d ₄ = 1.04 n _d2 = 1.52542 ν _d2 = 55.78
r ₅ = -3.097 (aspherical surface) d ₅ = (variable)
r ₆ = -12.215 d ₆ = 1.47 n _d3 = 1.60687 ν _d3 = 27.03
r ₇ = 3.297 (aspherical surface) d ₇ = (variable)
r ₈ = ∞ d ₈ = 0.50 n _d4 = 1.51633 ν _d4 = 64.14
r ₉ = ∞ d ₉ = 0.50
r ₁₀ = ∞ (image plane)
Aspheric coefficient 1st surface K = -7.174
A ₄ = -1.73070 × 10 ^-2
A ₆ = 3.06473 × 10 ^-3
A ₈ = -1.63074 × 10 ^-4
Second side K = 3.550
A ₄ = -1.82537 × 10 ^-2
A ₆ = 2.76246 × 10 ^-3
A ₈ = -1.11684 × 10 ^-7
4th surface K = -0.941
A ₄ = 4.04086 × 10 ^-3
A ₆ = -3.87560 × 10 ^-6
A ₈ = 0
Fifth side K = -0.008
A ₄ = 2.26929 × 10 ^-2
A ₆ = -3.17886 × 10 ^-3
A ₈ = 4.12539 × 10 ^-4
Surface 7 K = -3.456
A ₄ = 1.22516 × 10 ^-2
A ₆ = 7.77757 × 10 ^-3
A ₈ = 7.53862 × 10 ^-4
Zoom data (∞)
WE ST TE
f (mm) 3.986 6.387 10.839
F _NO 2.80 3.48 4.62
ω (°) 37.0 ° 20.0 ° 11.5 °
d ₂ 5.56 2.65 0.50
d ₅ 0.10 0.14 0.28
d ₇ 3.55 4.82 6.79.

  Next, the values of conditional expressions (1) to (14) in the above embodiments will be shown.

Conditional expression (1) (2) (3) (4) (5)
β _23t β _23w
Example 1 33 2.74 1.00 -1.74 -0.63 -0.03
Example 2 80 1.85 1.00 -1.38 -0.74 -0.01
Example 3 27 2.74 1.00 -1.78 -0.65 -0.04
Example 4 44 2.74 1.00 -1.74 -0.64 -0.02
Example 5 16 2.73 1.00 -1.51 -0.55 0.07
Example 6 236 2.74 1.00 -1.66 -0.61 0.00
Example 7 9 2.75 1.00 -1.85 -0.67 -0.11
Example 8 15 2.73 1.00 -1.82 -0.67 -0.06
Example 9 18 2.71 0.86 -1.53 -0.56 -0.07
Example 10 28 2.72 0.91 -1.62 -0.60 -0.04
Example 11 29 2.72 0.88 -1.51 -0.56 -0.04
.

Conditional expression (6) (7) (8) (9) (10) (11)
Example 1 -0.76 13.3 0.50 -0.05 0.85 55.78
Example 2 -0.75 22.6 0.53 -0.03 0.86 55.78
Example 3 -0.72 16.2 0.49 -0.05 0.76 64.14
Example 4 -0.72 16.2 0.45 -0.04 0.65 81.54
Example 5 -0.77 6.6 0.65 -0.15 2.08 55.78
Example 6 -0.75 15.7 0.58 -0.07 0.75 64.14
Example 7 -0.71 11.6 -0.37 -0.13 1.64 81.54
Example 8 -0.72 5.3 0.47 -0.09 1.01 55.78
Example 9 -0.70 21.9 0.32 -0.19 0.78 55.78
Example 10 -0.72 39.8 0.34 -0.13 0.45 64.14
Example 11 -0.72 39.9 0.25 -0.15 0.57 81.54
.

Conditional expression (12) (13) (14)
Example 1 55.78 27.03 -25.0
Example 2 55.78 27.03 -23.2
Example 3 55.78 64.14 -25.0
Example 4 55.78 27.03 -25.0
Example 5 64.14 27.03 -27.9
Example 6 59.38 30.21 -25.0
Example 7 81.54 27.03 -24.7
Example 8 59.38 27.03 -25.0
Example 9 55.78 27.03 -25.0
Example 10 59.38 30.21 -24.9
Example 11 55.78 27.03 -25.0
.

  By the way, in all the zoom lenses (variable magnification optical systems) of the above embodiments, distortion is relatively large. Therefore, when the subject image information is taken in via the electronic image sensor, the video signal output from the electronic image sensor includes the distortion information. That is, image data having distortion is taken into the electronic imaging apparatus. An example of such optical distortion is barrel distortion as shown in FIG. In the case of the barrel distortion, the distortion is such that the image on the screen 101 that should originally be at the position indicated by the broken line becomes the image on the screen 102 formed at the solid line position.

  In all the embodiments described above, such distortion is electrically corrected. The electrical correction method will be described below.

In order to correct the distortion in the video signal with optical distortion captured via the electronic image pickup device as described above, first, the video signal is converted into a digital signal and written in the image memory. Then, the distortion is corrected on the image memory by reading according to the distortion characteristics. In FIG. 24, when there is no distortion, the lattice-shaped image is an image 101 indicated by a broken line. On the other hand, when there is distortion, the lattice-shaped image is an image 102 indicated by a broken line. In a state where optical distortion occurs in the optical system as in the zoom lens of the present invention, the image 101 indicated by the broken line is stored in the image memory like the solid line image 102 due to the optical distortion described above. Therefore, in order to correct this distortion, when the pre-correction image data is read from the image memory, the pre-correction image data stored at the point P _{a at the} timing when the point P _A should be read, and the point P _B reading the uncorrected image data stored in P _b point timing to read out, similarly to Bae-out timing of reading the P _D point uncorrected image data stored in the P _d points, respectively. In this way, the pre-correction image 102 is read as an image of the original grid-like screen 101 without distortion indicated by a broken line, so that an image with corrected optical distortion is displayed.

  FIG. 25 is a block configuration diagram of an apparatus having an image processing function for performing optical distortion correction. In this apparatus, first, a subject image is formed on the imaging surface of a CCD (electronic imaging device) 2 via the zoom lens 1 of the present invention. The subject image formed on the imaging surface of the CCD 2 includes the optical distortion as described above. This subject image is converted into an electrical signal by the CCD 2. The electrical signal from the CCD 2 is subjected to predetermined processing by the imaging process circuit 3 and is supplied to the A / D conversion circuit 4 as a video signal. The video signal converted into a digital signal by the A / D conversion circuit 4 is stored in the image memory 5. Writing and reading of signals to and from the image memory 5 are controlled by the write control circuit 10 and the read control circuit 12A.

  The SSG (synchronization signal generation) circuit 9 generates a reference timing signal. The SSG (synchronization signal generation) circuit 9 supplies the reference timing signal to a TG (timing generation) circuit 8, the imaging process circuit 3, the write control circuit 10, and the read control circuit 12A, which will be described later. The TG circuit 8 sends readout timing signals in the horizontal (H) direction and vertical (V) direction from the SSG circuit 9 to the CCD 2. The correction amount ROM 13A stores correction amount data determined in advance for each part of the screen. What is stored as the predetermined correction amount is, for example, a correction amount address value for correcting optical distortion determined by the relationship between the position on the solid line and the position on the broken line, as shown in FIG.

  Then, a signal (data) is read from the image memory 5 by the read signal output from the read control circuit 12A. At this time, the signal is read from the image memory 5 to correct the optical distortion. The read signal is interpolated by the interpolation processing circuit 6, converted to an analog signal by the D / A converter 7, and output.

  In the case of a digital camera (electronic camera), the image memory 5 may not have enough room. In such a case, the timing may be changed for a time corresponding to the optical distortion correction amount before storing in the image memory 5, that is, when reading the video signal from the CCD 2.

  Next, the chromatic aberration of magnification can also be corrected to the electrical system by performing distortion correction similar to the above for each color separation image. In all the embodiments described above, not only distortion aberration but also lateral chromatic aberration are electrically corrected simultaneously.

  By the way, in the variable magnification optical system of the above embodiment, glass or a resin material is used for the lens, but an organic-inorganic composite material may be used instead. The organic-inorganic composite usable in the present invention will be described.

  The organic-inorganic composite is a composite in which an organic component and an inorganic component are mixed and combined at a molecular level or nanoscale. Its form is (1) a structure in which a polymer matrix composed of an organic skeleton and a matrix composed of an inorganic skeleton are intertwined with each other and penetrated into each other's matrix. There are those in which inorganic fine particles (so-called nanoparticles) sufficiently smaller than the light wavelength of the scale are uniformly dispersed, and (3) those having a composite structure of these. Some interaction acts between the organic component and the inorganic component, such as intermolecular forces such as hydrogen bonds, dispersion forces, and Coulomb forces, and attractive forces due to covalent bonds, ionic bonds, and π electron cloud interactions. In the organic-inorganic composite, as described above, the organic component and the inorganic component are mixed at a molecular level or a scale region smaller than the wavelength of light. For this reason, there is almost no influence on light scattering, and a transparent body can be obtained. Further, as derived from the Maxwell equation, the material reflects the optical characteristics of the organic component and the inorganic component. Therefore, various optical characteristics (refractive index, wavelength dispersion) are developed according to the types and abundance ratios of the organic component and the inorganic component. From this, various optical characteristics can be obtained by blending the organic component and the inorganic component in an arbitrary ratio.

Table 1 below shows a composition example of an organic-inorganic composite of acrylate resin (ultraviolet curable) and zirconia (ZrO ₂ ) nanoparticles. Table 2 shows a composition example of an organic-inorganic composite of an acrylate resin and zirconia (ZrO ₂ ) / alumina (Al ₂ O ₃ ) nanoparticles. Table 3 shows a composition example of an organic-inorganic composite of acrylate resin and niobium oxide (Nb ₂ O ₅ ) nanoparticles. Table 4 shows a composition example of an organic-inorganic composite of acrylate resin, zirconium alkoxide, and alumina (Al ₂ O ₃ ) nanoparticles.

Table 1
┌────┬────┬────┬┬────┬────┬────┬─────┐
│ zirconia _{│n d │ν d │n C │n F} │n g │ Notes │
│A content│ │ │ │ │ │ │
├────┼────┼────┼┼────┼────┼────┼─────┤
│ 0 │1.49236 │57.85664 │1.48981 │1.49832 │1.50309 │Acrylic │
│ │ │ │ │ │ │ 100% │
├────┼────┼────┼┼────┼────┼────┼─────┤
│ 0.1 │1.579526 │54.85037 │1.57579 │1.586355 │1.59311 │ │
├────┼────┼────┼┼────┼────┼────┼─────┤
│ 0.2 │1.662128 │53.223 │1.657315 │1.669756 │1.678308│ │
├────┼────┼────┼┼────┼────┼────┼─────┤
│ 0.3 │1.740814│52.27971│1.735014│1.749184│1.759385│ │
├────┼────┼────┼┼────┼────┼────┼─────┤
│ 0.4 │1.816094│51.71726│1.809379│1.825159│1.836887│ │
├────┼────┼────┼┼────┼────┼────┼─────┤
│ 0.5 │1.888376 │51.3837 │1.880807 │1.898096 │1.911249│ │
└────┴────┴────┴┴────┴────┴────┴─────┘
.

Table 2
┌───┬───┬────┬────┬────┬────┬┬────┬────┐
_{│AlsO 3 │ZrOs │n d │ν d │n} C │n F │n g │ Notes │
│ presence rate │ presence rate │ │ │ │ │ │
├───┼───┼────┼────┼────┼────┼┼────┼────┤
│0.1 │0.4 │1.831515│53.56672│1.824851│1.840374│1.851956│Acryl│
│ │ │ │ │ │ │ │50% │
├───┼───┼────┼────┼────┼────┼┼────┼────┤
│0.2 │0.3 │1.772832│56.58516│1.767125│1.780783│1.790701│ │
├───┼───┼────┼────┼────┼────┼┼────┼────┤
│0.3 │0.2 │1.712138│60.97687│1.707449│1.719127│1.727275│ │
├───┼───┼────┼────┼────┼────┼┼────┼────┤
│0.4 │0.1 │1.649213│67.85669│1.645609│1.655177│1.661429│ │
├───┼───┼────┼────┼────┼────┼┼────┼────┤
│0.2 │0.2 │1.695632│58.32581│1.690903│1.702829│1.774891│ │
└───┴───┴────┴────┴────┴────┴┴────┴────┘
.

Table 3
┌───┬───┬────┬────┬────┬┬────┬────┐
_{│NbsO 5 │AlsO 3 │n d │ν d} │n C │n F │n g │
│Content│Content│ │ │ │ │ │
├───┼───┼────┼────┼────┼┼────┼────┤
│0.1 │ 0 │1.589861│29.55772│1.584508│1.604464│1.617565│
├───┼───┼────┼────┼────┼┼────┼────┤
│0.2 │ 0 │1.681719 │22.6091 │1.673857 │1.70401 │1.724457│
├───┼───┼────┼────┼────┼┼────┼────┤
│0.3 │ 0 │1.768813 │19.52321 │1.758673 │1.798053 │1.8251 │
├───┼───┼────┼────┼────┼┼────┼────┤
│0.4 │ 0 │1.851815 │17.80818 │1.839583 │1.887415 │1.920475│
├───┼───┼────┼────┼────┼┼────┼────┤
│0.5 │ 0 │1.931253 │16.73291 │1.91708 │1.972734 │2.011334│
└───┴───┴────┴────┴────┴┴────┴────┘
.

Table 4
┌─────┬──────┬────┬────┬┬────┬────┐
￨AlsOc (film) │ zirconia A _{│n d │ν d │n C │n F} │
│Content │Lucoxide │ │ │ │ │
├─────┼──────┼────┼────┼┼────┼────┤
│ 0 │ 0.3 │1.533113│58.39837│1.530205│1.539334│
├─────┼──────┼────┼────┼┼────┼────┤
│ 0.1 │ 0.27 │1.54737 │62.10192│1.544525│1.553339│
├─────┼──────┼────┼────┼┼────┼────┤
│ 0.2 │ 0.24 │1.561498│66.01481│1.558713│1.567219│
├─────┼──────┼────┼────┼┼────┼────┤
│ 0.3 │ 0.21 │1.575498│70.15415│1.572774│1.580977│
├─────┼──────┼────┼────┼┼────┼────┤
│ 0.4 │ 0.18 │1.589376│74.53905│1.586709│1.594616│
└─────┴──────┴────┴────┴┴────┴────┘
.

  Now, an electronic apparatus provided with the variable power optical system and the imaging optical system of the present invention as described above will be described. In this electronic apparatus, an imaging device is used that forms an object image with the optical system and receives the image with an imaging element such as a CCD to take an image. Electronic devices include a digital camera, a video camera, a digital video unit, a personal computer which is an example of an information processing device, a mobile computer, a telephone, a mobile phone particularly useful for carrying, and an information portable terminal. The embodiment is illustrated below.

  26 to 28 are examples of a digital camera, and are conceptual diagrams of a configuration in which the variable magnification optical system according to the present invention is used as the photographing optical system 41. 26 is a front perspective view showing the appearance of the digital camera 40, FIG. 27 is a rear perspective view thereof, and FIG. 28 is a cross-sectional view showing the configuration of the digital camera 40.

  In this example, the digital camera 40 includes a photographing optical system 41, a finder optical system 43, a shutter 45, a flash 46, a liquid crystal display monitor 47, and the like. The photographing optical system 41 is disposed on the photographing optical path 42. The finder optical system 43 is disposed on a finder optical path 44 different from the photographing optical path 42. In addition, a shutter 45 is provided on the upper portion of the camera 40. Therefore, when the photographer presses the shutter 45, photographing is performed through the photographing optical system 41, for example, the variable magnification optical system of the first embodiment. The object image formed by the photographing optical system 41 is formed on the imaging surface of the CCD 49 via the parallel plate P1 and the cover glass P2. Here, a near ultraviolet ray cut coat is applied to the parallel plate P1. Further, the parallel plate P1 may have a low-pass filter action. The object image received by the CCD 49 is displayed on the liquid crystal display monitor 47 as an electronic image via the processing means 51. The liquid crystal display monitor 47 is provided on the back of the camera. Further, the processing means 51 is connected to a recording means 52 so that a photographed electronic image can be recorded. The recording means 52 may be provided separately from the processing means 51. For example, the recording means 52 may be a floppy disk, a memory card, an MO, or the like. As described above, the recording unit 52 may be configured to perform recording and writing electronically. Further, in place of the CCD 49, a silver salt camera having a silver salt film may be configured.

  A finder objective optical system 53 is disposed on the finder optical path 44. The object image formed by the finder objective optical system 53 is formed on the field frame 57. Here, the field frame 57 is provided on a Porro prism 55 which is an image erecting member. Behind this polyprism 55 is an eyepiece optical system 59 that guides the erect image to the observer eyeball E. Note that a cover member 50 is disposed on the entrance side of the photographing optical system 41 and the finder objective optical system 53 and on the exit side of the eyepiece optical system 59, respectively. Here, although a plane parallel plate is disposed as the cover member 50, a lens having power may be used.

  The digital camera 40 configured as described above can achieve high performance and downsizing since the photographing optical system 41 is high performance and small.

  Next, FIG. 29 to FIG. 31 are personal computers as an example of an information processing apparatus, and are conceptual diagrams of configurations using the variable magnification optical system of the present invention as an objective optical system. 29 is a front perspective view with the cover of the personal computer 300 opened, FIG. 30 is a sectional view of the photographing optical system 303 of the personal computer 300, and FIG. 31 is a side view of the state of FIG.

  The personal computer 300 includes a keyboard 301 for a writer to input information from the outside, a monitor 302 for displaying information to the operator, and a photographing optical system 303 for photographing the operator himself and surrounding images. ing. Furthermore, the personal computer 300 has information processing means and recording means not shown. Here, the monitor 302 may be a transmissive liquid crystal display element that is illuminated from the back by a backlight (not shown), a reflective liquid crystal display element that reflects and displays light from the front, a CRT display, or the like. In the drawing, the photographing optical system 303 is built in the upper right of the monitor 302, but is not limited to that location. For example, it may be anywhere around the monitor 302 or around the keyboard 301.

  The photographing optical system 303 has an objective lens 112 made up of a variable magnification optical system (abbreviated in the drawing) according to the present invention and an image sensor chip 162 that receives an image on a photographing optical path 304. These are built in the personal computer 300.

  Here, a plane parallel plate group F such as an optical low-pass filter is additionally attached on the image sensor chip 162. Therefore, the imaging element chip 162 and the plane parallel plate group F are integrated to form the imaging unit 160. The imaging unit 160 can be fitted and attached to the rear end of the lens frame 113 of the objective lens 112 with one touch. Therefore, centering of the objective lens 112 and the image sensor chip 162 and adjustment of the surface interval are unnecessary, and assembly is simple. A cover glass 114 for protecting the objective lens 112 is disposed at the tip of the lens frame 113. The driving mechanism for the variable magnification optical system in the lens frame 113 is not shown.

  The object image received by the image sensor chip 162 is input to the processing means of the personal computer 300 via the terminal 166. The object image is displayed on the monitor 302 as an electronic image. FIG. 29 shows an image 305 photographed by the operator as an example. The image 305 can also be displayed on the personal computer of the communication partner from a remote location via the processing means, the Internet, or the telephone.

  Next, FIG. 32 is a telephone which is an example of an information processing apparatus, and is a conceptual diagram of a configuration using the variable magnification optical system of the present invention as a photographing optical system. Here, the telephone is a mobile phone that is convenient to carry. 32A is a front view of the mobile phone 400, FIG. 32B is a side view, and FIG. 32C is a sectional view of the photographing optical system 405.

  The cellular phone 400 includes a microphone unit 401, a speaker unit 402, an input dial 403, a monitor 404, a photographing optical system 405, an antenna 406, and processing means (not shown). An operator's voice is input to the microphone unit 401 as information. The speaker unit 402 outputs the voice of the other party. The input dial 403 has buttons for an operator to input information. The monitor 404 displays a photographed image of the operator himself / herself and the other party, information such as a telephone number. The antenna 406 transmits and receives communication radio waves. Here, the monitor 404 is a liquid crystal display element. In the drawing, the arrangement positions of the respective components are not particularly limited to these. The photographing optical system 405 is disposed on the photographing optical path 407. The photographing optical system 405 includes an objective lens 112 including a variable magnification optical system (abbreviated in the drawing) according to the present invention, and an image sensor chip 162 that receives an object image. These are built in the mobile phone 400.

  Here, a plane parallel plate group F such as an optical low-pass filter is additionally attached on the image sensor chip 162. Therefore, the imaging element chip 162 and the plane parallel plate group F are integrated to form the imaging unit 160. The imaging unit 160 can be fitted and attached to the rear end of the lens frame 113 of the objective lens 112 with one touch. Therefore, centering of the objective lens 112 and the image sensor chip 162 and adjustment of the surface interval are unnecessary, and assembly is simple. A cover glass 114 for protecting the objective lens 112 is disposed at the tip of the lens frame 113. The driving mechanism for the variable magnification optical system in the lens frame 113 is not shown.

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

  The variable power optical system of the present invention and the electronic apparatus using the same can be configured as follows, for example.

    [1] In a variable magnification optical system having a negative refractive power at the most object side and having at least a second lens group and a third lens group in order from the object side, from the wide-angle end to the telephoto end A variable magnification optical system satisfying the following conditional expression at the time of zooming:

2 <| d _w12 −d _t12 | / | d _w23 −d _t23 | <300 (1)
Where d _w12 : the distance between the first lens group and the second lens group at the wide-angle end,
d _t12 : the distance between the first lens group and the second lens group at the telephoto end,
d _w23 : the distance between the second lens group and the third lens group at the wide-angle end,
d _t23 : the distance between the second lens group and the third lens group at the telephoto end,
It is.

    [2] Variable magnification optical system composed of a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having negative refractive power in order from the object side 2. The variable magnification optical system according to 1 above, wherein the zoom lens system satisfies the following conditional expressions simultaneously.

1.5 <β <30 (2)
0.5 <L _t / L _w <1.3 (3)
Where β is the zoom ratio of the optical system,
L _t : Optical total length at the telephoto end,
L _w : Optical total length at the wide-angle end,
It is.

    [3] The zoom optical system according to 1 or 2 above, wherein the following conditional expressions are simultaneously satisfied at the time of zooming from the wide-angle end to the telephoto end.

_{β 23t <-1 <β 23w ···} (4)
−0.2 <(d _w23 −d _t23 ) / f _w <0.2 (5)
Where β _23w is the combined lateral magnification at the wide angle end of the optical system after the second lens group,
β _23t : Composite lateral magnification at the telephoto end of the optical system after the second lens group,
d _w23 : group interval between the second lens unit and the third lens unit at the wide-angle end,
d _t23 : the distance between the second lens group and the third lens group at the telephoto end,
f _w : focal length of the entire system at the wide-angle end,
It is.

    [4] The variable magnification optical system according to any one of 1 to 3 above, wherein the following conditional expression is satisfied.

-1.5 <f _w / EX _w <0 (6)
Where EX _{w is} the exit pupil position measured from the image plane at the wide-angle end,
f _w : focal length of the entire system at the wide-angle end,
It is.

    [5] The variable magnification optical system according to any one of 1 to 4, wherein the following conditional expression is satisfied.

2 <f _w / d _w23 <100 (7)
Where f _{w is} the focal length of the entire system at the wide-angle end,
d _w23 : group interval between the second lens unit and the third lens unit at the wide-angle end,
It is.

    [6] The variable magnification optical system according to any one of 1 to 5, wherein any two lens groups are constituted by a single lens.

    [7] The variable magnification optical system as set forth in any one of [1] to [5], wherein all the lens groups are composed of a single lens.

    [8] The imaging apparatus according to any one of 1 to 7, wherein the optical total length is fixed at the time of zooming.

    [9] The variable magnification optical system according to any one of 1 to 8, wherein the negative lens of the first lens group satisfies the following conditional expression.

0 <SF _G1 <2 (8)
Where SF _G1 is the shaping factor of the first lens group and is defined as SF _G1 = (r _G11 + r _G12 ) / (r _G11 −r _G12 )
r _G11 : radius of curvature of the most object side surface of the first lens group,
r _G12 : radius of curvature of the most image-side surface of the first lens group,
It is.

    [10] The variable magnification optical system according to any one of 1 to 9, wherein the second lens group satisfies the following conditional expression.

-2 <SF _G2 <0.1 (9)
Where SF _G2 is the shaping factor of the second lens group and is defined as SF _G2 = (r _G21 + r _G22 ) / (r _G21 −r _G22 )
r _G21 : radius of curvature of the surface closest to the object side of the second lens group,
r _G22 : radius of curvature of the most image-side surface of the second lens group,
It is.

    [11] The zoom lens system according to any one of [1] to [10], wherein at least one negative lens of the third lens group satisfies the following conditional expression:

−0.5 <SF ₃ <4 (10)
Where SF ₃ is the shaping factor of the negative lens of the third lens group, and is defined by SF ₃ = (r ₃₁ + r ₃₂ ) / (r ₃₁ −r ₃₂ )
r ₃₁ : radius of curvature of the object side surface of the negative lens of the third lens group,
r ₃₂ : radius of curvature of the image side surface of the negative lens of the third lens group,
It is.

    [12] The variable magnification optical system according to any one of [1] to [11], wherein the first lens group includes at least one cemented lens.

    [13] The variable power optical system as set forth in any one of [1] to [12], wherein the first lens group includes at least one positive lens.

    [14] The variable magnification optical system as described in 13 above, wherein the positive lens is disposed closest to the image side.

    [15] The zoom optical system according to any one of 1 to 14, wherein the second lens group includes at least one cemented lens.

    [16] The variable magnification optical system according to any one of [1] to [15], wherein the second lens group includes at least one negative lens.

    [17] The variable power optical system as described in 16 above, wherein the negative lens is disposed closest to the image side.

    [18] The variable magnification optical system according to any one of [1] to [17], wherein the negative lens of the first lens group has an aspheric surface on the object side surface.

    [19] The variable magnification optical system as set forth in any one of [1] to [18], wherein the negative lens of the first lens group has an aspherical surface on the image side.

    [20] The variable power optical system as described in any one of 1 to 19, wherein at least one positive lens included in the second lens group has an aspheric surface on the object side.

    [21] The variable magnification optical system according to any one of [1] to [20], wherein at least one positive lens included in the second lens group has an aspheric surface on the image side.

    [22] The variable magnification optical system according to any one of [1] to [21], wherein the negative lens of the first lens group is a lens made of a resin material.

    [23] The variable magnification optical system according to any one of [1] to [22], wherein at least one positive lens included in the second lens group is made of a resin material.

    [24] The variable magnification optical system as set forth in any one of [1] to [23], wherein at least one negative lens of the third lens group is made of a resin material.

    [25] The variable magnification optical system as set forth in any one of [1] to [24], wherein the negative lens of the first lens group is made of a material satisfying the following conditional expression.

40 <ν _d1 <100 (11)
Where ν _{d1 is} the Abbe number of the negative lens in the first lens group,
It is.

    [26] The variable magnification optical system according to any one of [1] to [25], wherein the positive lens of the second lens group is made of a material that satisfies the following conditional expression.

40 <ν _d2 <100 (12)
Where ν _{d2 is} the Abbe number of the positive lens in the first lens group,
It is.

    [27] The variable magnification optical system according to any one of [1] to [26], wherein at least one negative lens of the third lens group is made of a material satisfying the following conditional expression.

0 <ν _d3 <40 (13)
Where ν _{d3 is} the Abbe number of the negative lens in the third lens group,
It is.

    [28] The variable magnification optical system as described in any one of 1 to 27 above, wherein the following conditional expression is satisfied.

−30 <DT _min <20 (14)
However, DT _min : Minimum distortion amount [%],
It is.

    [29] The variable power optical system as set forth in any one of [1] to [28], wherein distortion aberration generated in the optical system is electrically corrected.

    [30] The variable power optical system as set forth in any one of [1] to [29], wherein chromatic aberration of magnification generated in the optical system is electrically corrected.

    [31] The variable power optical system as described in any one of 1 to 30 above, wherein an organic-inorganic composite material is used as an optical material of at least one optical element constituting the optical system.

    [32] The variable magnification optical system as described in 31 above, wherein the organic-inorganic composite includes zirconia nanoparticles.

    [33] The variable magnification optical system as described in 31 above, wherein the organic-inorganic composite contains nanoparticles of zirconia and alumina.

    [34] The variable magnification optical system as set forth in [31], wherein the organic-inorganic composite includes niobium oxide nanoparticles.

    [35] The variable magnification optical system as set forth in [31], wherein the organic-inorganic composite includes a hydrolyzate of zirconium alkoxide and nanoparticles of alumina.

    [36] An electronic apparatus comprising: the variable magnification optical system according to any one of 1 to 35 above; and an electronic imaging device disposed on the image side thereof.

FIG. 3 is a lens cross-sectional view at a wide angle end (a), an intermediate state (b), and a telephoto end (c) when focusing on an object point at infinity according to Example 1 of the variable magnification optical system of the present invention. FIG. 3 is a lens cross-sectional view similar to FIG. 1 of the variable magnification optical system of Example 2. FIG. 4 is a lens cross-sectional view similar to FIG. 1 of the variable magnification optical system of Example 3. FIG. 6 is a lens cross-sectional view similar to FIG. 1 of the variable magnification optical system of Example 4. FIG. 6 is a lens cross-sectional view similar to FIG. FIG. 6 is a lens cross-sectional view similar to FIG. 1 of the variable magnification optical system of Example 6. FIG. 10 is a lens cross-sectional view similar to FIG. 1 of the variable magnification optical system of Example 7. 10 is a lens cross-sectional view similar to FIG. 1 of a variable magnification optical system according to Example 8. FIG. 10 is a lens cross-sectional view similar to FIG. 1 of a variable magnification optical system according to Example 9. FIG. 12 is a lens cross-sectional view similar to FIG. 12 is a lens cross-sectional view similar to FIG. 1 of a variable magnification optical system according to Example 11. FIG. FIG. 6 is an aberration diagram at the wide-angle end (a), the intermediate state (b), and the telephoto end (c) when focusing on an object point at infinity according to Example 1. FIG. 13 is an aberration diagram similar to FIG. 12 of Example 2. FIG. 13 is an aberration diagram similar to FIG. 12 of Example 3. FIG. 13 is an aberration diagram similar to FIG. 12 of Example 4. FIG. 13 is an aberration diagram similar to FIG. 12 of Example 5. FIG. 13 is an aberration diagram similar to FIG. 12 of Example 6. FIG. 13 is an aberration diagram similar to FIG. 12 of Example 7. FIG. 13 is an aberration diagram similar to FIG. 12 of Example 8. FIG. 13 is an aberration diagram similar to FIG. 12 of Example 9. FIG. 13 is an aberration diagram similar to FIG. 12 of Example 10. FIG. 13 is an aberration diagram similar to FIG. 12 of Example 11. It is an aberration diagram showing an example of the distortion aberration amount DT _min . It is an optical distortion figure which shows the barrel distortion as an example of an optical distortion, and the image of an original screen. It is a block block diagram of an example of the image processing apparatus which performs optical distortion correction. It is a front perspective view which shows the external appearance of the digital camera incorporating the variable magnification optical system by this invention. FIG. 27 is a rear perspective view of the digital camera of FIG. 26. It is sectional drawing of the digital camera of FIG. It is the front perspective view which opened the cover of the personal computer incorporating the variable magnification optical system by this invention as an objective optical system. It is sectional drawing of the imaging optical system of a personal computer. It is a side view of the state of FIG. FIG. 2 is a front view (a), a side view (b), and a sectional view (c) of the photographing optical system of a mobile phone in which the variable magnification optical system according to the present invention is incorporated as an objective optical system.

Explanation of symbols

G1 ... first lens group G2 ... second lens group G3 ... third lens group S ... aperture stop F ... parallel plane plate group I ... image plane E ... observer eyeball 1 ... zoom lens 2 ... CCD
3 ... Imaging process circuit 4 ... A / D conversion circuit 5 ... Image memory 6 ... Interpolation processing circuit 7 ... D / A converter 8 ... TG (timing generation) circuit 9 ... SSG (synchronization signal generation) circuit 10 ... Write control circuit 12A ... Read control circuit 13A ... Correction amount ROM
40 ... Digital camera 41 ... Shooting optical system 42 ... Shooting optical path 43 ... Viewfinder optical system 44 ... Viewfinder optical path 45 ... Shutter 46 ... Flash 47 ... Liquid crystal display monitor 49 ... CCD
DESCRIPTION OF SYMBOLS 50 ... Cover member 51 ... Processing means 52 ... Recording means 53 ... Viewfinder objective optical system 55 ... Porro prism 57 ... Field frame 59 ... Eyepiece optical system 101 ... Screen 102 without distortion ... Screen 112 with optical distortion ... Objective lens 113 ... Mirror frame 114 ... Cover glass 160 ... Imaging unit 162 ... Imaging device chip 166 ... Terminal 300 ... PC 301 ... Keyboard 302 ... Monitor 303 ... Shooting optical system 304 ... Shooting optical path 305 ... Image 400 ... Mobile phone 401 ... Microphone Unit 402 ... speaker unit 403 ... input dial 404 ... monitor 405 ... photographing optical system 406 ... antenna 407 ... photographing optical path

Claims (2)

In a variable magnification optical system having a negative refractive power at the most object side and having at least a second lens group and a third lens group in order from the object side, at the time of zooming from the wide angle end to the telephoto end A variable magnification optical system characterized by satisfying the following conditional expression:
2 <| d _w12 −d _t12 | / | d _w23 −d _t23 | <300 (1)
Where d _w12 : the distance between the first lens group and the second lens group at the wide-angle end,
d _t12 : the distance between the first lens group and the second lens group at the telephoto end,
d _w23 : the distance between the second lens group and the third lens group at the wide-angle end,
d _t23 : the distance between the second lens group and the third lens group at the telephoto end,
It is. An electronic apparatus comprising: the variable magnification optical system according to claim 1; and an electronic image pickup device disposed on an image side thereof.