JP2005156828A - Variable power optical system and electronic device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable power optical system with which both the reduction of a cost and the miniaturization can be effectively attained, and to provide an electronic device using the variable power optical system. <P>SOLUTION: Regarding the variable power optical system constituted of a 1st group G1 having negative refractive power, a 2nd group G2 having positive refractive power, a 3rd group G3 having negative refractive power and a 4th group G4 having positive refractive power, at least one lens is molded by using a 1st material which becomes a surface including an optical function surface after being molded, and a 2nd material which becomes a surface other than the surface including the optical function surface after being molded, and the lens is the integrated lens obtained by integrally molding the 1st material and the 2nd material. <P>COPYRIGHT: (C)2005,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. Some of these devices have a digital camera function and a digital video function. In order to realize these functions, a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) sensor is used as an imaging device. In order to reduce the size of such a device, it is preferable to use an image sensor having a relatively small effective area of the light receiving surface. In this case, it is necessary to achieve both miniaturization and cost reduction while maintaining high performance of the optical system. At this time, the number of lenses has been reduced as an approach to miniaturization. On the other hand, as an approach to cost reduction by reducing man-hours, for example, Patent Document 1 proposes a manufacturing method in which a lens is pressure-molded in a lens holder.

  In order to reduce the number of lenses constituting the optical system, it is necessary to use an aspheric lens. In order to manufacture this aspherical lens, a processing method (hereinafter referred to as a conventional processing method) in which a preform is pressed and molded in a heat-softened state is generally used. In this conventional processing method, molding is performed slightly larger than the required outer diameter, and centering (outer diameter rounding) is performed to incorporate it into the lens barrel. Therefore, for example, to mold a positive lens, the outer peripheral thickness at the required outer diameter is thicker than the outer peripheral thickness at the time of centering. Further, when the number of lenses is reduced for miniaturization, the refractive power of each lens including the positive lens is increased, so that the lens thickness is also increased. For this reason, since it is necessary to secure the outer peripheral thickness at the time of centering, the outer peripheral thickness at the required outer diameter is further increased, and it cannot be said that the effect of downsizing is sufficiently obtained.

On the other hand, Patent Document 1 does not describe not only miniaturization, but also does not describe conditions for miniaturization.
JP-A-61-114822

  The present invention has been made in view of such a situation in the prior art, and an object of the present invention is to provide a variable magnification optical system capable of effectively achieving both cost reduction and downsizing and an electronic apparatus using the same. Is to provide.

  The first variable magnification optical system of the present invention that achieves the above object has, in order from the object side, a first group having negative refractive power, a second group having positive refractive power, and negative refractive power. A variable magnification optical system including a third group and a fourth group having a positive refractive power, wherein at least one lens is a surface including at least an optical functional surface after molding. And a second material that is a surface other than the surface including at least the optical functional surface after molding, and is formed of an integrated lens in which the first material and the second material are integrated. It is characterized by.

  In the first variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described.

  A variable power optical system composed of a negative refractive power lens group, a positive refractive power lens group, a negative refractive power lens group, and a positive refractive power lens group in this order can achieve a fixed total length with a small number of lenses. . Therefore, such a variable magnification optical system is suitable for downsizing and cost reduction. And by using an integral lens, the optical system can be further miniaturized. This is because the integral lens does not need to secure the outer peripheral thickness at the time of centering as compared with the conventional processing method. This point will be described.

  In the conventional processing method, it is assumed that centering is performed. Therefore, a certain amount of thickness (edge thickness) is required on the outer periphery of the lens before centering. Therefore, the conventional lens is a lens having a thick central thickness (a thickness of the central portion). In contrast, the integral lens used in the first variable magnification optical system of the present invention is a lens with a thin edge thickness. Therefore, the total length of the optical system can be shortened. Further, in the conventional processing method, as the power of the positive lens is increased, the outer peripheral thickness at the required outer diameter is further increased. On the other hand, in the first variable magnification optical system of the present invention, it is not necessary to secure the outer peripheral thickness at the time of centering. Therefore, it can be said that as the power of the positive lens increases, the effect of downsizing increases.

  In addition, since such an integral lens is easy to handle, it is possible to reduce the cost for manufacturing the variable magnification optical system.

  In the zoom optical system of the present invention, for example, zooming from the wide-angle end to the telephoto end is performed while moving the second group and the third group independently to the object side. Of course, zooming may be performed while moving the first group or the first group.

  The second variable power optical system of the present invention is characterized in that in the first variable power optical system, the integrated lens is cemented with another lens.

  In the second variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. In this way, by combining the integral lens and another lens, the eccentricity sensitivity (eccentric error) can be made smaller than when the individual lenses are assembled independently. Therefore, the assembly of the optical system is facilitated, leading to cost reduction.

  The third variable magnification optical system according to the present invention is an aspheric integral lens in which at least one optical functional surface of the integral lens is an aspheric surface in the first and second variable magnification optical systems. Is.

  In the third variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. Various aberrations can be suppressed by using such an aspherical surface. As a result, the number of lenses in the entire system can be reduced. Further, the cost and size of the optical system can be reduced.

  The fourth variable power optical system of the present invention is characterized in that, in the first to third variable power optical systems, the first group has at least one positive lens.

  In the fourth variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. Since the first group has negative power, it has at least one negative lens. Therefore, by including a positive lens in the first group, it is possible to suppress variations in various aberrations such as spherical aberration, coma aberration, and chromatic aberration of magnification due to zooming.

  A fifth variable magnification optical system according to the present invention is characterized in that in the first to fourth variable magnification optical systems, a negative lens is provided on the most object side of the first group.

  In the fifth variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. In this way, the effective lens diameter of the first group and the total lens length can be shortened.

  The sixth variable magnification optical system of the present invention is characterized in that, in the first to fifth variable magnification optical systems, the first group has at least one integrated lens.

  In the sixth variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. Since the first group of lenses has a large effective diameter, the required volume increases. Therefore, the volume of the optical material can be reduced by using an integral lens for the first lens group. As a result, cost can be reduced.

  A seventh variable power optical system according to the present invention is characterized in that, in the sixth variable power optical system, at least one of the integrated lenses of the first group has a positive refractive power.

  In the seventh variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. By making the positive lens arranged in the first group an integral lens, the edge thickness of the positive lens can be reduced and the overall length can be shortened.

  For the first lens group positive lens, it is preferable to use an optical material having a high refractive index and high dispersion in order to correct lateral chromatic aberration and spherical aberration at the telephoto end. However, in general, an optical material having a high refractive index and high dispersion is expensive. In addition, since the positive lens of the first group has a large effective diameter, the required volume increases. Therefore, the volume of the optical material necessary for the positive lens can be reduced by using the positive lens as an integral lens. Therefore, cost can be reduced. Further, since the volume of the lens itself is reduced, the optical system can be miniaturized.

  The eighth variable power optical system of the present invention is characterized in that, in the seventh variable power optical system, at least one positive lens of the first group satisfies the following conditional expression.

0.1 <HH1 / φ1 <10 (1)
However, HH1: principal point interval (mm) of the first lens group positive lens,
φ1: refracting power of the first lens group positive lens,
It is.

  In the eighth variable power optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. If a negative lens is arranged in the first group, lateral chromatic aberration occurs. In order to correct the lateral chromatic aberration and the like with a small number of lenses, that is, at a low cost, it is preferable to have a positive lens with a large power in the first group. However, in the conventional processing method, the lens is molded slightly larger than the required outer diameter, and centering (rounding of the outer diameter) is performed, and the lens is assembled into the lens barrel. Therefore, when the positive lens is molded, the outer peripheral portion thickness at the required outer diameter becomes thicker than the outer peripheral portion thickness at the time of centering. Further, when the power of the positive lens is increased, the outer peripheral portion thickness at the required outer diameter is further increased due to the necessity of securing the outer peripheral portion thickness at the time of centering. As a result, it is difficult to achieve both low cost and downsizing. However, by molding the positive lens of the first group integrally, it is not necessary to mold it larger than the required outer diameter. Further, by satisfying conditional expression (1), a large power can be realized with a thin lens. Therefore, cost reduction and size reduction can be achieved at the same time.

  If the lower limit of 0.1 of conditional expression (1) is not reached, the power is too large compared to the principal point interval. For this reason, the eccentricity sensitivity is also increased, and it is difficult to maintain optical performance. On the other hand, when the upper limit of 10 is exceeded, the power is smaller than the principal point interval. For this reason, the lateral chromatic aberration and the like generated in the negative lens of the first group cannot be corrected. Alternatively, the number of lenses increases in order to correct lateral chromatic aberration and the like.

  Furthermore, it is preferable that the following conditional expression (1-2) is satisfied. In this case, the optical system can be reduced in size while maintaining low cost.

0.5 <HH1 / φ1 <6 (1-2)
Furthermore, it is more preferable to satisfy the following conditional expression (1-3). In this case, the optical system can be made smaller while keeping the cost low.

1 <HH1 / φ1 <4 (1-3)
According to a ninth variable power optical system of the present invention, in the sixth to eighth variable power optical systems, at least one of the integrated lenses of the first group is cemented with another lens. Is.

  In the ninth variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. By including such a cemented lens in the first group, the decentration sensitivity can be reduced. This facilitates assembly of the optical system, leading to cost reduction.

  According to a tenth variable magnification optical system of the present invention, in the sixth to eighth variable magnification optical systems, at least one of the integrated lenses of the first group has at least one aspheric surface. To do.

  In the tenth variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. At the wide-angle end of the variable magnification optical system of the present invention, the light height in the first group is high. Therefore, the first group includes at least one aspheric surface. In this way, off-axis aberrations such as astigmatism, distortion, and coma can be favorably corrected with a smaller number of lenses. Therefore, it is possible to reduce the size and cost of the optical system.

  At the telephoto end, the beam diameter in the first group is large. Therefore, by including at least one aspherical surface in the first group, spherical aberration, coma aberration, and the like can be favorably corrected with a smaller number of lenses. Also in this case, the optical system can be reduced in size and cost.

  An eleventh variable magnification optical system according to the present invention is characterized in that, in the first to tenth variable magnification optical systems, the second group has at least one negative lens.

  In the eleventh variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. Since the second group has positive power, it has at least one positive lens. Therefore, by including a negative lens, it is possible to suppress fluctuations in various aberrations such as chromatic aberration of magnification accompanying zooming.

  A twelfth variable magnification optical system according to the present invention is characterized in that, in the first to eleventh variable magnification optical systems, a positive lens is provided closest to the object side in the second group.

  In the twelfth variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. In the second group, it is necessary to converge the light diverged in the first group of negative power. Therefore, the most object side lens is preferably a positive lens.

  A thirteenth variable magnification optical system according to the present invention is characterized in that in the first to twelfth variable magnification optical systems, a negative lens is provided closest to the image side of the second group.

  In the thirteenth variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. By using the negative lens on the most image side of the second group, the following effects can be obtained. (1) Since the principal point position moves to the first group side, the distance between the principal points of the first group and the second group can be shortened. As a result, the overall lens length can be shortened. (2) Since the magnification of the second group can be increased, the amount of movement of the second group accompanying zooming can be reduced. As a result, the overall length can be shortened.

  According to a fourteenth variable magnification optical system of the present invention, in the first to thirteenth variable magnification optical systems, the second group includes at least one integrated lens, and at least one of the integrated lenses is positive. It has a refractive power.

  In the fourteenth variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. By using the positive lens as an integral lens, the edge thickness of the positive lens can be reduced. As a result, the overall length can be shortened.

  In addition, it is preferable to use an optical material having a high refractive index and low dispersion for the second group positive lens in order to suppress axial chromatic aberration, spherical aberration, astigmatism, and the like. However, in general, an optical material having a high refractive index and low dispersion is expensive. Therefore, the volume of the optical material necessary for the positive lens can be reduced by using the positive lens as an integral lens. Therefore, the cost can be reduced, which is preferable.

  Further, since the volume of the lens itself is reduced, the optical system can be miniaturized. Further, since the integrated lens is easy to handle, the cost for manufacturing the variable magnification optical system can be reduced.

  A fifteenth variable magnification optical system according to the present invention is characterized in that, in the fourteenth variable magnification optical system, at least one positive lens of the second group satisfies the following conditional expression.

0.1 <HH2 / φ2 <6 (2)
However, HH2: principal point interval (mm) of the second group positive lens,
φ2: refractive power of the second lens group positive lens,
It is.

  In the fifteenth variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. By increasing the power of the positive lens arranged in the second group, the moving distance of the second group can be shortened. This leads to shortening of the entire lens length. However, in the conventional processing method, the lens is molded slightly larger than the required outer diameter, and centering (rounding of the outer diameter) is performed, and the lens is assembled into the lens barrel. Therefore, when the positive lens is molded, the outer peripheral portion thickness at the required outer diameter becomes thicker than the outer peripheral portion thickness at the time of centering. Further, when the power of the positive lens is increased, the outer peripheral portion thickness at the required outer diameter is further increased due to the necessity of securing the outer peripheral portion thickness at the time of centering. As a result, it is difficult to achieve both shortening of the total lens length and downsizing of each lens. However, forming this positive lens integrally eliminates the need for molding larger than the required outer diameter. Further, by satisfying conditional expression (2), a large power can be realized with a thin lens. Therefore, further downsizing can be realized.

  If the lower limit of 0.1 to condition (2) is not reached, the power is too large compared to the principal point interval. For this reason, the eccentricity sensitivity is also increased, and it is difficult to maintain optical performance. On the other hand, when the upper limit of 6 is exceeded, the power is smaller than the principal point interval. Therefore, the moving amount of the second group cannot be shortened. As a result, the total lens length is increased.

  Furthermore, it is preferable that the following conditional expression (2-2) is satisfied. In this case, both shortening of the total lens length and downsizing of each lens can be achieved.

0.5 <HH2 / φ2 <3 (2-2)
Furthermore, it is more preferable to satisfy the following conditional expression (2-3). In this case, it is easier to achieve both shortening of the overall lens length and downsizing of each lens.

1 <HH2 / φ2 <2 (2-3)
The sixteenth variable magnification optical system according to the present invention is characterized in that, in the fourteenth and fifteenth variable magnification optical systems, at least one integrated lens of the second group is cemented with another lens. Is.

  In the sixteenth variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. By including such a cemented lens in the second group, decentration sensitivity can be reduced. This facilitates assembly of the optical system, leading to cost reduction.

  A seventeenth variable magnification optical system according to the present invention is characterized in that, in the fourteenth to sixteenth variable magnification optical systems, at least one of the integral lenses of the second group has at least one aspheric surface. To do.

  In the seventeenth variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. The luminous flux incident on the first group is expanded in diameter by the first group having negative refractive power. Therefore, the light beam diameter in the second group becomes large. Therefore, by including at least one aspheric surface in the second group, it is possible to satisfactorily correct variations in various aberrations. Therefore, it is possible to reduce the size and cost of the optical system. Further, in order to reduce the lens diameter, it is necessary to increase the power of each group. However, when the positive power of the second group is increased, changes in lateral magnification and aberration of the second group accompanying zooming increase. Therefore, it is desirable that the second group includes an aspherical surface in order to correct aberrations occurring in the second group and suppress aberration fluctuations accompanying zooming.

  According to an eighteenth variable magnification optical system of the present invention, in the first to seventeenth variable magnification optical systems, the third group has at least one integrated lens.

  In the 18th variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. As described above, since the integral lens is easy to handle, the cost for manufacturing the variable magnification optical system can be reduced.

  According to a nineteenth variable magnification optical system of the present invention, in the first to eighteenth variable magnification optical systems, the fourth group has at least one integrated lens.

  The reason why the above-described configuration is adopted in the nineteenth variable magnification optical system of the present invention and the operation thereof will be described. Since the fourth group lens has a large effective diameter, the volume of the optical material necessary for the lens also increases. Therefore, by using an integral lens for the fourth lens group, the volume of the optical material is reduced. Therefore, cost can be reduced. Moreover, since the integral lens is easy to handle, the cost for manufacturing the variable magnification optical system can be reduced.

  A twentieth variable magnification optical system according to the present invention is characterized in that, in the nineteenth variable magnification optical system, at least one of the integrated lenses is a positive lens having a positive refractive power.

  In the twentieth variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. By using the positive lens as an integral lens, the edge thickness of the positive lens can be reduced. As a result, the overall length of the lens system can be shortened.

  Further, since the fourth group lens has a large effective diameter, the volume of the optical material necessary for the lens also increases. Therefore, by using an integral lens for the fourth lens group, the volume of the optical material is reduced. Therefore, cost can be reduced. Moreover, since the integral lens is easy to handle, the cost for manufacturing the variable magnification optical system can be reduced.

  A twenty-first variable magnification optical system according to the present invention is characterized in that, in the twentieth variable magnification optical system, at least one positive lens of the fourth group satisfies the following conditional expression.

0.1 <HH4 / φ4 <10 (3)
However, HH4: Main point interval (mm) of the fourth group positive lens,
φ4: the refractive power of the fourth lens group
It is.

  In the twenty-first variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. Increasing the power of the fourth lens group positive lens leads to increasing the power of the entire fourth lens group. As a result, the overall length of the lens system can be shortened. Also, by increasing the power of the fourth lens group positive lens, the exit pupil position at the wide-angle end can be moved away from the image plane, so that it is easy to ensure image-side telecentricity. However, in the conventional processing method, the lens is molded slightly larger than the required outer diameter, and centering (rounding of the outer diameter) is performed, and the lens is assembled into the lens barrel. Therefore, when the positive lens is molded, the outer peripheral portion thickness at the required outer diameter becomes thicker than the outer peripheral portion thickness at the time of centering. Further, when the power of the positive lens is increased, the outer peripheral portion thickness at the required outer diameter is further increased due to the necessity of securing the outer peripheral portion thickness at the time of centering. As a result, it is difficult to achieve both shortening of the total lens length and downsizing of each lens. However, if this positive lens is molded integrally, it is not necessary to mold larger than the required outer diameter. Further, by satisfying conditional expression (3), a large power can be realized with a thin lens. Therefore, further downsizing can be realized.

  If the lower limit of 0.1 of the conditional expression (3) is not reached, the power is too large compared to the principal point interval, so that the decentration sensitivity also increases and it becomes difficult to maintain the optical performance. Exceeding the upper limit of 10 is not preferable because the power is smaller than the principal point interval, and the exit pupil position at the wide-angle end approaches the image plane, and image-side telecentricity cannot be secured.

  Furthermore, it is preferable that the following conditional expression (3-2) is satisfied. In this case, it is possible to achieve both shortening of the entire lens length and securing of image side telecentricity and size reduction of each lens.

0.5 <HH4 / φ4 <7 (3-2)
Furthermore, it is preferable that the following conditional expression (3-3) is satisfied. In this case, it is easier to achieve both shortening of the overall lens length, ensuring image side telecentricity, and downsizing of each lens.

1 <HH4 / φ4 <5 (3-3)
According to a twenty-second variable magnification optical system of the present invention, in the first to twenty-first variable magnification optical systems, the thickness of the thinnest portion of at least one integrated lens satisfies the following conditional expression: Is.

0.1 mm <t <0.5 mm (4)
Where t is the thickness of the thinnest part of the integral lens,
It is.

  In the twenty-second variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. If the thickness of the thinnest part of the integral lens is reduced, the lens can be made smaller. As a result, the overall lens length can be shortened. Therefore, by satisfying conditional expression (4), it is possible to reduce the size while maintaining the optical performance.

  If the lower limit of 0.1 mm of conditional expression (4) is not reached, the lens is too thin and deforms due to external pressure, temperature, etc., making it difficult to maintain optical performance. If the upper limit of 0.5 mm is exceeded, the thickness of the thinnest part increases, and the lens also increases.

  Furthermore, it is preferable that the following conditional expression (4-2) is satisfied. In this case, the optical system can be downsized while maintaining the optical performance.

0.15 mm <t <0.4 mm (4-2)
Furthermore, it is more preferable to satisfy the following conditional expression (4-3). In this case, the optical system can be further downsized while maintaining the optical performance.

0.2 mm <t <0.35 mm (4-3)
According to a twenty-third variable power optical system of the present invention, in the twenty-second variable power optical system, the integral lens has a positive refractive power.

  In the twenty-third variable magnification optical system of the present invention, the reason why this configuration is adopted and the operation thereof will be described. By using the positive lens as an integral lens, the edge thickness of the positive lens can be reduced. Therefore, the overall length of the lens system can be shortened.

  A twenty-fourth variable power optical system according to the present invention is characterized in that, in the first through twenty-third variable power optical systems, when the integral lens is molded, a plurality of optical functional surfaces are simultaneously molded by a single molding machine. To do.

  In the twenty-fourth variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. When a plurality of surfaces are simultaneously formed in parallel with one molding machine, the processing time per surface can be shortened. Further, by simultaneously molding a plurality of surfaces with one molding machine in this way, the life of the pressing die per number of surfaces can be extended. Thus, the cost can be greatly reduced.

  The 25th variable power optical system of the present invention is characterized in that, in the 1st to 24th variable power optical systems, the first material is glass.

  The reason for adopting the above configuration and the operation thereof in the twenty-fifth zoom optical system of the present invention will be described. By using a glass exhibiting a high refractive index as the first material, various aberrations such as spherical aberration and field curvature can be favorably corrected with a small number of sheets. Moreover, it becomes difficult to receive the influence of a temperature change by using glass. Therefore, it is possible to realize an optical system with a small back focus fluctuation at the time of temperature change. Of course, other plastics and organic-inorganic composite materials can also be used as the first material.

  According to a twenty-sixth variable magnification optical system of the present invention, in the first to twenty-fifth variable magnification optical systems, the second material has a light shielding property.

  In the twenty-sixth variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. When the second material has light shielding properties, it is possible to minimize the arrival of light rays from surfaces other than the optical functional surface. Therefore, it is preferable because ghost light and flare light can be suppressed.

  According to a twenty-seventh variable magnification optical system of the present invention, in the first to twenty sixth variable magnification optical systems, the second material is a metal, cermet, or ceramics.

  The reason and the operation of the above-described configuration in the twenty-seventh variable magnification optical system of the present invention will be described. If the second material is a metal, cermet (composite material of ceramics and metal), or ceramics, the shape can be easily processed.

  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, an organic-inorganic composite material is used as an optical material of at least one optical element constituting the optical system. It is.

  In the 28th variable magnification optical system of the present invention, the reason why the above configuration is adopted and the operation thereof will be described. 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 and inorganic components (obtained). ). Thus, an optical material having desired optical characteristics or high optical characteristics can be realized by blending an organic component and an inorganic component in an arbitrary ratio. Thereby, since an optical element with high performance can be obtained, various aberrations can be corrected with a smaller number of sheets. Therefore, the optical system can be reduced in cost and size.

  A twenty-ninth variable magnification optical system according to the present invention is the twenty-eighth variable magnification optical system, wherein the organic-inorganic composite includes zirconia nanoparticles.

  The 30th variable magnification optical system of the present invention is the 28th variable magnification optical system, characterized in that the organic-inorganic composite includes nanoparticles of zirconia and alumina.

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

  The thirty-second variable power optical system of the present invention is the twenty-eighth variable power optical system, wherein the organic-inorganic composite includes a hydrolyzate of zirconium alkoxide and alumina nanoparticles.

  In the 29th to 32nd 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-second variable power optical systems and an electronic image pickup device arranged on the image side thereof.

  In the electronic device of the present invention, the reason why the above configuration is adopted 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 effectively achieve both cost reduction and size reduction of the variable magnification optical system, and electronic devices using the same can achieve cost reduction and size reduction as well.

  The variable power optical system of the present invention is shown below. An integral lens is used in this variable magnification optical system. Therefore, first, a manufacturing method of the integral lens will be described with reference to FIG. In FIG. 5A, reference numeral 14 denotes a lower pressing mold of the integral lens molding die, and 15 denotes an upper pressing mold of the integral lens molding die. An integrated lens bottom surface mold (hereinafter referred to as a bottom surface mold) is formed in a predetermined region of the lower pressing mold 14. This lower surface mold corresponds to the portion of the optical functional surface in the molded integrated lens. An integral lens upper surface mold (hereinafter referred to as an upper surface mold) is also formed in a predetermined region of the upper pressing mold 15. This upper surface mold also corresponds to the portion of the optical function surface in the integrated lens after molding.

  The integral lens 10 is molded using a first material 11 and a second material 12. The first material 11 is formed with a surface including at least an optical functional surface after the integral lens is molded. The second material 12 is formed with a surface other than at least the surface including the optical function surface after the integral lens is molded. The surfaces other than the surface including the optical function surface are surfaces formed on the outer peripheral portion of the surface formed by the first material 11. This surface is, for example, a surface that contacts the lens barrel and supports the integral lens, or a centering surface.

  A hole 13 is formed in the second material 12. Therefore, in manufacturing the integrated lens 10, as shown in FIG. 5A, the first material 11 and the second material 12 are placed on the lower pressing die 14 of the integrated lens molding die. At this time, the first material 11 is arranged in a state of being inserted into the hole 13. In this state, the first material 11 is heated to a deformable temperature. This temperature is an appropriate temperature higher than the transition point of the first material 11. Next, when an appropriate temperature is reached, the upper pressing die 15 of the integral lens molding die descends from above until it comes into contact with the surface of the second material 12. Accordingly, the first material 11 is pressed by the lower surface mold and the upper surface mold. As a result, the first material 11 is molded into a shape corresponding to the lower surface mold and the upper surface mold, and the integrated lens 10 is molded as a whole as shown in FIG. The integrated lens 10 can be easily taken out from the lower pressing die 14 after the upper pressing die 15 in FIG. 5B is removed. Further, as shown in the perspective view of FIG. 6, the integrated lens 10 is formed by integrating the first material 11 into the hole of the second material 12. In FIG. 5, one set of the first material 11 and the second material 12 is placed on the pair of pressing dies 14 and 15, but the configuration is not limited thereto. Another example is shown below.

  FIG. 8 shows another example in which a plurality of surface molds are arranged in parallel in each of the pair of pressing molds 14 and 15. A plurality of first materials 11 and a plurality of second materials 12 are placed corresponding to the respective surface molds. In this way, a plurality of integral lenses are molded simultaneously. In FIG. 8A, reference numeral 14 denotes a lower pressing die of the integral lens molding die, and 15 denotes an upper pressing die of the integral lens molding die. A plurality of integral lens bottom surface molds (hereinafter referred to as bottom surface molds) are formed in a predetermined region of the lower pressing mold 14. This lower surface mold corresponds to the portion of the optical functional surface in the molded integrated lens. In addition, a plurality of integrated lens upper surface molds (hereinafter referred to as upper surface molds) are also formed in a predetermined region of the upper pressing mold 15. This upper surface mold also corresponds to the portion of the optical function surface in the integrated lens after molding.

  As shown in FIG. 8A, the integrated lens of this example is also molded using the first material 11 and the second material 12. The first material 11 forms a surface including at least an optical functional surface after the molding of the integral lens. Further, the second material 12 forms a surface other than at least the surface including the optical function surface after the molding of the integral lens. The surfaces other than the surface including the optical function surface are surfaces formed on the outer peripheral portion of the surface formed by the first material 11. This surface is, for example, a surface that contacts the lens barrel and supports the integral lens, or a centering surface.

  A plurality of holes 13 are formed in the second material 12. Therefore, in this example, the integral lenses are formed in an array. Then, by cutting the integrated lens 10 ′ (hereinafter referred to as an arrayed lens 10 ′) formed in an array shown in FIG. 9, the integrated lens 10 shown in FIG. 6 is obtained. In manufacturing the arrayed lens 10 ′, as shown in FIG. 8A, the plurality of first materials 11 are placed together with the second material 12 on the lower pressing die 14 of the integral lens molding die. The At this time, each of the first materials 11 is arranged in a state of being inserted into each hole 13. In this state, the first material 11 is heated to a deformable temperature. This temperature is an appropriate temperature higher than the transition point of the first material 11. Next, when an appropriate temperature is reached, the upper pressing die 15 of the integral lens molding die descends from above until it comes into contact with the surface of the second material 12. Thereby, each 1st raw material 11 is pressed by a lower surface type | mold and an upper surface type | mold. As a result, the first material 11 is formed into a shape corresponding to the lower surface mold and the upper surface mold, and the array lens 10 ′ is formed as shown in FIG. 8B as a whole. In this example, as shown in FIG. 8, the concave shape portion 17 is simultaneously processed in the second material 12 by providing the upper mold 15 with the convex shape 16 and pressing it. The arrayed lens 10 ′ can be easily taken out from the lower pressing die 14 after the upper pressing die 15 in FIG. 8B is removed. Further, in the array lens 10 ′, as shown in a perspective view in FIG. 9, each first material 11 is fused and integrated in each hole 13 of the second material 12. Then, the 2nd raw material 12 is cut | disconnected and the some integrated lens 10 is obtained. 8 and 9, the lens array is 3 × 3, but the number is not limited to this.

  Next, Example 1 and Example 2 of the variable magnification optical system (zoom lens) of the present invention will be described with reference to the drawings. FIG. 1 and FIG. 2 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 and 2, respectively. In each figure, G1 is the first lens group, G2 is the second lens group, G3 is the third lens group, G4 is the fourth lens group, S is the aperture stop, F is the near-infrared cut filter, low-pass filter, and electronic imaging A plane parallel plate group such as a cover glass of the element, I denotes an image plane. Further, spherical aberration, astigmatism, chromaticity of magnification (aberration), distortion of the wide-angle end (a), the intermediate state (b), the telephoto end (c) at the time of focusing on an object point at infinity according to the first and second embodiments. Aberration diagrams are shown in FIGS. 3 and 4, respectively. In these aberration diagrams, “FIY” represents the image height.

  The variable magnification optical system of Example 1 is shown in FIG. The variable magnification optical system of Example 1 includes, in order from the object side, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. 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 together with the aperture stop S toward the object side, and the third lens group G3 is the fourth lens group G3. The fourth lens group G4 is fixed by moving to the object side while narrowing the distance between the lens group G4 and then expanding.

  The first lens group G1 has a negative power as a whole. The first lens group G1 includes a cemented lens composed of a biconcave negative lens and a positive meniscus lens having a concave surface facing the image side. The aspheric surfaces are the most object side surface and the most image side surface of the cemented lens.

  The second lens group G2 has a positive power as a whole. The second lens group G2 includes, in order from the object side, a biconvex positive lens and a cemented lens of a biconvex positive lens and a biconcave negative lens. The aspheric surfaces are the object side surface of the biconvex positive lens, the most object side surface and the most image side surface of the cemented lens.

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

  The fourth lens group G4 has positive power. The fourth lens group G4 includes a positive meniscus lens having a concave surface directed toward the object side. The aspheric surface is the image-side surface of the positive meniscus lens.

  All lenses constituting the variable magnification optical system according to the present example are integral lenses except for the negative meniscus lens in the third lens group G3. This integral lens is manufactured by the method shown in FIG.

  An example of the integrated lens 10 is shown in FIG. This integrated lens 10 is used in the variable magnification optical system according to the present embodiment. FIG. 7 is a cross-sectional view of a biconvex positive lens on the object side of the second lens group G2. In this lens, a biconvex positive lens is an integrated lens. The thickness of the second material 12 is 0.4 mm. At this time, although not shown in FIG. 7, a hole or a concavo-convex shape may be simultaneously processed in the second material 12 during molding.

  The variable magnification optical system of Example 2 is shown in FIG. The variable magnification optical system of Example 2 includes, in order from the object side, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. 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 to the object side integrally with the aperture stop S, and the third lens group G3 is the fourth lens group G3. The distance from the lens group G4 is slightly narrowed and then moved to the object side while being widened, and the fourth lens group G4 is fixed.

  The first lens group G1 has a negative power as a whole. The first lens group G1 includes a cemented lens composed of a biconcave negative lens and a positive meniscus lens having a concave surface facing the image side. The aspheric surfaces are the most object side surface and the most image side surface of the cemented lens.

  The second lens group G2 has a positive power as a whole. The second lens group G2 includes, in order from the object side, a biconvex positive lens and a cemented lens of a biconvex positive lens and a biconcave negative lens. The aspheric surfaces are the object side surface of the biconvex positive lens of the single lens, the most object side surface and the most image side surface of the cemented lens.

  The third lens group G3 has negative power. The third lens group G3 is composed of a biconcave negative lens. The aspheric surface is the image-side surface of the negative meniscus lens.

  The fourth lens group G4 has positive power. The fourth lens group G4 is composed of a biconvex positive lens. The aspheric surface is the image-side surface of the biconvex positive lens.

  All lenses constituting the variable magnification optical system according to the present example are integral lenses except for the biconcave negative lens of the second lens group G2. This integral lens is manufactured by the method shown in FIG.

  An example of the integrated lens 10 is shown in FIG. This integrated lens 10 is used in the variable magnification optical system according to the present embodiment. FIG. 10 is a cross-sectional view of the cemented lens of the first lens group G2. In this cemented lens, the biconvex positive lens on the object side is an integrated lens 10. A biconcave negative lens is cemented to the image side. The thickness of the second material 12 is 0.5 mm. At this time, although not shown in FIG. 10, a hole or a concavo-convex shape may be processed in the second material 12 at the time of molding (see FIG. 8).

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 + A ₁₀ y ¹⁰
Here, r is a paraxial radius of curvature, K is a conical coefficient, and A ₄ , A ₆ , A ₈ , and A ₁₀ are fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients, respectively.

Example 1
r ₁ = -15.253 (aspherical surface) d ₁ = 0.60 n _d1 = 1.69350 ν _d1 = 53.21
r ₂ = 4.141 d ₂ = 0.96 n _d2 = 1.68893 ν _d2 = 31.07
r ₃ = 12.214 (aspherical surface) d ₃ = (variable)
r ₄ = ∞ (aperture) d ₄ = 0.10
r ₅ = 9.919 (aspherical surface) d ₅ = 0.68 n _d3 = 1.49700 ν _d3 = 81.54
r ₆ = -11.002 d ₆ = 0.10
r ₇ = 3.141 (aspherical surface) d ₇ = 1.33 n _d4 = 1.74320 ν _d4 = 49.34
r ₈ = -6.830 d ₈ = 0.62 n _d5 = 1.68893 ν _d5 = 31.07
r ₉ = 3.671 (aspherical surface) d ₉ = (variable)
r ₁₀ = 11.080 d ₁₀ = 1.06 n _d6 = 1.68893 ν _d6 = 31.07
r ₁₁ = 3.943 (aspherical surface) d ₁₁ = (variable)
r ₁₂ = -13.947 d ₁₂ = 1.11 n _d7 = 1.68893 ν _d7 = 31.07
r ₁₃ = -4.584 (aspherical surface) d ₁₃ = 1.69
r ₁₄ = ∞ d ₁₄ = 0.50 n _d8 = 1.51633 ν _d8 = 64.14
r ₁₅ = ∞
Aspherical coefficient 1st surface K = 19.399
A ₄ = -9.52491 × 10 ^-4
A ₆ = 4.99000 × 10 ^-5
A ₈ = 1.01862 × 10 ^-5
A ₁₀ = 0
3rd side K = -14.812
A ₄ = -8.97149 × 10 ^-4
A ₆ = 4.01691 × 10 ^-6
A ₈ = 1.68687 × 10 ^-5
A ₁₀ = 0
Fifth side K = 19.348
A ₄ = -4.82828 × 10 ^-3
A ₆ = 8.06209 × 10 ^-4
A ₈ = -1.99532 × 10 ^-4
A ₁₀ = 0
Surface 7 K = -1.011
A ₄ = 7.47480 × 10 ^-3
A ₆ = -2.60867 × 10 ^-4
A ₈ = 8.69323 × 10 ^-5
A ₁₀ = 0
The ninth side K = -9.730
A ₄ = 3.91180 × 10 ^-2
A ₆ = -4.30584 × 10 ^-3
A ₈ = 1.54137 × 10 ^-3
A ₁₀ = 0
11th surface K = -5.280
A ₄ = 1.20789 × 10 ^-2
A ₆ = -8.05017 × 10 ^-4
A ₈ = 1.88007 × 10 ^-6
A ₁₀ = 0
Surface 13 K = -1.512
A ₄ = 1.20543 × 10 ^-4
A ₆ = -1.73187 × 10 ^-4
A ₈ = 5.42052 × 10 ^-6
A ₁₀ = 0
Zoom data (∞)
WE ST TE
f (mm) 4.7 7.6 13.0
F _NO 2.8 3.8 5.1
ω (°) 30.3 18.1 10.7
d ₃ 5.47 2.88 0.18
d ₉ 0.74 0.35 1.39
d ₁₁ 0.74 3.72 5.38.

Example 2
r ₁ = -8.395 (aspherical surface) d ₁ = 0.60 n _d1 = 1.67790 ν _d1 = 55.34
r ₂ = 4.439 d ₂ = 0.98 n _d2 = 1.68893 ν _d2 = 31.07
r ₃ = 21.458 (aspherical surface) d ₃ = (variable)
r ₄ = ∞ (aperture) d ₄ = 0.08
r ₅ = 13.194 (aspherical surface) d ₅ = 0.65 n _d3 = 1.49700 ν _d3 = 81.54
r ₆ = -10.912 d ₆ = 0.19
r ₇ = 2.999 (aspherical surface) d ₇ = 1.34 n _d4 = 1.74320 ν _d4 = 49.34
r ₈ = -5.935 d ₈ = 0.60 n _d5 = 1.68893 ν _d5 = 31.07
r ₉ = 3.541 (aspherical surface) d ₉ = (variable)
r ₁₀ = -54.527 d ₁₀ = 0.60 n _d6 = 1.68893 ν _d6 = 31.07
r ₁₁ = 6.260 (aspherical surface) d ₁₁ = (variable)
r ₁₂ = 30.988 d ₁₂ = 1.48 n _d7 = 1.68893 ν _d7 = 31.07
r ₁₃ = -5.446 (aspherical surface) d ₁₃ = 1.00
r ₁₄ = ∞ d ₁₄ = 0.50 n _d8 = 1.51633 ν _d8 = 64.14
r ₁₅ = ∞
Aspheric coefficient 1st surface K = 0.576
A ₄ = -6.63222 × 10 ^-4
A ₆ = 5.19142 × 10 ^-5
A ₈ = 3.41858 × 10 ^-6
A ₁₀ = 0
Third side K = -31.443
A ₄ = -4.24448 × 10 ^-4
A ₆ = -2.32455 × 10 ^-7
A ₈ = 1.82275 × 10 ^-5
A ₁₀ = 0
Fifth side K = 32.850
A ₄ = -2.19377 × 10 ^-3
A ₆ = -7.72833 × 10 ^-5
A ₈ = 7.53132 × 10 ^-6
A ₁₀ = 0
Surface 7 K = -1.055
A ₄ = 7.33888 × 10 ^-3
A ₆ = 4.41996 × 10 ^-4
A ₈ = -1.81717 × 10 ^-5
A ₁₀ = 0
The ninth side K = -10.179
A ₄ = 4.50999 × 10 ^-2
A ₆ = -4.61578 × 10 ^-3
A ₈ = 1.84744 × 10 ^-3
A ₁₀ = 0
11th surface K = -24.461
A ₄ = 1.24411 × 10 ^-2
A ₆ = -2.06313 × 10 ^-3
A ₈ = 1.94143 × 10 ^-4
A ₁₀ = 0
Surface 13 K = -11.947
A ₄ = -4.12632 × 10 ^-3
A ₆ = 2.43311 × 10 ^-4
A ₈ = -7.32948 × 10 ^-6
A ₁₀ = 0
Zoom data (∞)
WE ST TE
f (mm) 4.7 7.6 13.0
F _NO 2.8 3.8 5.0
ω (°) 31.6 18.2 10.6
d ₃ 6.04 3.32 0.55
d ₉ 1.34 1.32 2.66
d ₁₁ 1.76 4.49 5.93.

  Next, the values of conditional expressions (1) to (3) in the above embodiments will be shown.

Example 1 Example 2
Conditional expression (1) 3.63 3.26
Conditional expression (2)
(Object side lens) 2.36 2.55
(Image side lens) 1.60 1.48
Conditional expression (3) 4.56 4.01.

  By the way, in the variable magnification optical system of the above embodiments, glass is used for all lenses, but it is possible to use a resin material. When the lens is made of a resin material, the lens can be produced by a molding method of the resin material and can be easily produced in large quantities. In addition, since the material cost is low, an inexpensive optical system can be realized.

  Further, an organic-inorganic composite material may be used instead of glass. 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 entangled 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. Therefore, various optical characteristics can be obtained by blending organic and inorganic components in any 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.

  FIGS. 11 to 13 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. 11 is a front perspective view showing the appearance of the digital camera 40, FIG. 12 is a rear perspective view thereof, and FIG. 13 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 viewfinder 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 photographic 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 unit 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 cover members 50 are arranged on the incident side of the photographic 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. 14 to FIG. 16 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. 14 is a front perspective view with the cover of the personal computer 300 opened, FIG. 15 is a sectional view of the photographing optical system 303 of the personal computer 300, and FIG. 16 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. Further, 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. 14 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. 17 is a telephone which is an example of an information processing apparatus, and is a conceptual diagram of a configuration in which the variable power optical system of the present invention is used as a photographing optical system. Here, the telephone is a mobile phone that is convenient to carry. 17A is a front view of the mobile phone 400, FIG. 17B is a side view, and FIG. 17C is a cross-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 order from the object side, a first group having a negative refractive power, a second group having a positive refractive power, a third group having a negative refractive power, and a fourth group having a positive refractive power A variable magnification optical system comprising: a first material in which at least one lens is a surface including at least an optical functional surface after molding; and a surface other than a surface including at least an optical functional surface after molding. A variable magnification optical system comprising an integral lens molded using a second material to be a surface and in which the first material and the second material are integrated.

    [2] The variable magnification optical system as described in 1 above, wherein the integral lens is cemented with another lens.

    [3] The variable power optical system as described in [1] or [2], wherein at least one optical functional surface of the integrated lens is an aspherical integrated lens.

    [4] The zoom optical system according to any one of 1 to 3, wherein the first group includes at least one positive lens.

    [5] The variable magnification optical system as set forth in any one of [1] to [4], further including a negative lens closest to the object side of the first group.

    [6] The zoom optical system according to any one of 1 to 5, wherein the first group includes at least one integrated lens.

    [7] The variable magnification optical system as set forth in [6], wherein at least one of the integrated lenses of the first group is a positive lens having a positive refractive power.

    [8] The variable magnification optical system as set forth in [7], wherein at least one positive lens in the first group satisfies the following conditional expression:

0.1 <HH1 / φ1 <10 (1)
However, HH1: principal point interval of the first group positive lens,
φ1: refracting power of the first lens group positive lens,
It is.

    [9] The variable power optical system as described in any one of [6] to [8], wherein at least one integrated lens of the first group is cemented with another lens.

    [10] The variable magnification optical system according to any one of [6] to [9], wherein the at least one integral lens of the first group has at least one aspheric surface.

    [11] The variable power optical system as set forth in any one of [1] to [10], wherein the second group has at least one negative lens.

    [12] The variable magnification optical system according to any one of [1] to [11], further including a positive lens closest to the object side in the second group.

    [13] The variable magnification optical system according to any one of 1 to 12, further including a negative lens closest to the image side of the second group.

    [14] The variation according to any one of [1] to [13], wherein the second group includes at least one integrated lens, and at least one of the integrated lenses has a positive refractive power. Double optical system.

    [15] The variable power optical system as described in 14 above, wherein at least one positive lens of the second group satisfies the following conditional expression.

0.1 <HH2 / φ2 <6 (2)
Where HH2 is the principal point interval of the second group positive lens,
φ2: refractive power of the second lens group positive lens,
It is.

    [16] The variable power optical system as described in 14 or 15 above, wherein at least one integrated lens of the second group is cemented with another lens.

    [17] The variable power optical system as described in any one of [14] to [16], wherein at least one integrated lens of the second group has at least one aspherical surface.

    [18] The variable power optical system as set forth in any one of [1] to [17], wherein the third group includes at least one integrated lens.

    [19] The zoom optical system according to any one of [1] to [18], wherein the fourth group includes at least one integrated lens.

    [20] The variable power optical system as described in 19 above, wherein at least one of the integrated lenses is a positive lens having a positive refractive power.

    [21] The variable power optical system as described in 20 above, wherein at least one positive lens of the fourth group satisfies the following conditional expression:

0.1 <HH4 / φ4 <10 (1)
Where HH4: the distance between the principal points of the fourth group positive lens,
φ4: the refractive power of the fourth lens group
It is.

    [22] The variable magnification optical system according to any one of [1] to [21], wherein a thickness of a thinnest portion of at least one integrated lens satisfies the following conditional expression:

0.1 mm <t <0.5 mm (4)
Where t is the thickness of the thinnest part of the integral lens,
It is.

    [23] The variable power optical system as described in 22 above, wherein the integral lens has a positive refractive power.

    [24] The variable power optical system as set forth in any one of [1] to [23], wherein when the integral lens is molded, a plurality of optical functional surfaces are simultaneously molded by a single molding machine.

    [25] The variable magnification optical system as set forth in any one of [1] to [24], wherein the first material is glass.

    [26] The variable power optical system as set forth in any one of [1] to [25], wherein the second material has a light shielding property.

    [27] The zoom optical system according to any one of [1] to [26], wherein the second material is metal, cermet, or ceramics.

    [28] The variable power optical system as described in any one of 1 to 27 above, wherein an organic-inorganic composite material is used as an optical material of at least one optical element constituting the optical system.

    [29] The variable magnification optical system as described in 28 above, wherein the organic-inorganic composite includes zirconia nanoparticles.

    [30] The variable power optical system as described in 28 above, wherein the organic-inorganic composite includes nanoparticles of zirconia and alumina.

    [31] The variable power optical system as described in 28 above, wherein the organic-inorganic composite includes niobium oxide nanoparticles.

    [32] The variable power optical system as described in 28 above, wherein the organic-inorganic composite includes a hydrolyzate of zirconium alkoxide and alumina nanoparticles.

    [33] An electronic apparatus comprising: the variable magnification optical system according to any one of 1 to 32 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. 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. 4 is an aberration diagram similar to FIG. 3 of Example 2. FIG. 4 is a diagram for explaining a method of manufacturing an integral lens used in the variable magnification optical system of Example 1, and shows an arrangement (a) before molding and an arrangement (b) after molding. It is a perspective view which shows the integral lens shape | molded with the manufacturing method of FIG. 2 is a cross-sectional view illustrating an example of an integral lens used in the variable magnification optical system of Example 1. FIG. FIG. 6 is a diagram for explaining a method of manufacturing an integral lens used in the variable magnification optical system of Example 2, and is a diagram showing an arrangement (a) before molding and an arrangement (b) after molding. It is a perspective view which shows the integral lens shape | molded with the manufacturing method of FIG. 6 is a cross-sectional view showing an example of an integral lens used in a variable magnification optical system of Example 2. FIG. 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. 12 is a rear perspective view of the digital camera of FIG. 11. 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 ... 1st lens group G2 ... 2nd lens group G3 ... 3rd lens group G4 ... 4th lens group S ... Aperture stop F ... Parallel plane plate group I ... Image plane E ... Observer eyeball 10 ... Integrated lens 10 '... Integrated lens 11 ... first material 12 ... second material 13 ... hole 14 formed in the second material ... lower pressing die 15 of the molding die ... upper pressing die 16 of the molding die ... convex shape portion 17 ... concave shape portion 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 ... Finder objective optical system 55 ... Porro prism 57 ... Field frame 59 ... Eyepiece optical system 112 ... Objective lens 113 ... Lens frame 114 ... Cover glass 160 ... Imaging unit 162 ... Image sensor chip 166 ... Terminal 300 ... Personal computer 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 ... Shooting optics System 406 ... Antenna 407 ... Imaging optical path

Claims (5)

In order from the object side, a first group having negative refractive power, a second group having positive refractive power, a third group having negative refractive power, and a fourth group having positive refractive power In the variable magnification optical system, at least one lens becomes a surface other than a first material that includes at least an optical functional surface after molding and a surface that includes at least the optical functional surface after molding. A variable power optical system comprising an integral lens molded using a second material and in which the first material and the second material are integrated. The variable magnification optical system according to claim 1, wherein the second material has a light shielding property. 3. The variable magnification optical system according to claim 1, wherein the second material is metal, cermet, or ceramics. 4. A variable magnification optical system according to claim 1, wherein an organic-inorganic composite material is used as an optical material of at least one optical element constituting the optical system. 5. An electronic apparatus comprising: the variable magnification optical system according to claim 1; and an electronic image pickup device disposed on the image side thereof.

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