JP4508610B2 - Variable magnification optical system and electronic apparatus using the same - Google Patents

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 variable magnification optical system of the present invention that achieves the above object, in order from the object side, is a first group having a negative refractive power, a second group having a positive refractive power, and a third group having a positive refractive power. And a fourth group having negative refractive power,
At the time of zooming from the wide angle end to the telephoto end, the first group moves along a concave locus on the object side, the telephoto end is located at the same position as the wide angle end, and the second group moves toward the object side. The third group and the fourth group are a variable magnification optical system that is fixed,
The first group includes, in order from the object side, a biconcave negative lens and a positive meniscus lens having a concave surface facing the image side.
The second group is composed of, in order from the object side, a positive lens, and a cemented lens of a biconvex lens and a biconcave lens;
The third group includes a positive lens,
The fourth group is composed of a negative meniscus lens having a convex surface facing the image side,
At least one lens is molded using a first material that becomes a surface including at least an optical functional surface after molding, and a second material that becomes a surface other than the surface including at least an optical functional surface after molding. , Comprising an integrated lens in which the first material and the second material are integrated,
The first group includes at least one integrated lens, at least one of the integrated lenses has a positive refractive power, and the at least one positive lens satisfies the following conditional expression: To do.
^{0.1mm 2 <HH1 / φ1 ≦ 4.17mm} 2 ··· (1 ')
However, HH1: principal point interval of the first group positive lens,
φ1: refracting power of the first lens group positive lens,
It is.

The first to thirty-third variable power optical systems and the electronic equipment using the variable power optical systems that form the background of the variable power optical system of the present invention will be described below.
The first variable magnification optical system includes, in order from the object side, a first group having negative refractive power, a second group having positive refractive power, a third group having positive refractive power, and negative refraction. A variable power optical system configured by a fourth group having power, wherein at least one lens has a surface including at least an optical functional surface after molding, and at least an optical function after molding It is formed using a second material which is a surface other than the surface including the surface, and is formed of an integrated lens in which the first material and the second material are integrated.
In the first variable magnification optical system, 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 positive refractive power lens group, and a negative refractive power lens group in this order can be configured with a small number of lenses. Suitable for cost reduction 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). On the other hand, the integral lens used in the first variable magnification optical system is a lens having 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, 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 such a zoom optical system, zooming from the wide angle end to the telephoto end is performed while changing at least the distance between the first group and the second group, and the second group and the third group. Is good. Of course, zooming may be performed while changing the distance between the other groups and the distance between the fourth group and the image plane. The third group may be a lens group that moves for focusing.

  The second variable magnification optical system is characterized in that, in the first variable magnification optical system, the integral lens is cemented with another lens.

  The reason why the second variable magnification optical system adopts the above configuration 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 is an aspherical integrated lens in which at least one optical functional surface of the integrated lens is an aspherical surface in the first and second variable magnification optical systems. .

  The reason why the third variable power optical system adopts the above configuration 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.

  According to a fourth variable power optical system, in the first to third variable power optical systems, the first group includes at least one positive lens.

  In the fourth variable magnification optical system, the reason for adopting the above configuration 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.

  The fifth variable power optical system is characterized in that in the first to fourth variable power optical systems, a negative lens is provided on the most object side of the first group.

  The reason why the fifth variable magnification optical system has the above-described configuration 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.

  A sixth variable magnification optical system 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, the reason for adopting the above configuration 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.

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

  The seventh variable power optical system is the sixth variable power optical system, wherein at least one of the integrated lenses has a positive refractive power.

  In the seventh variable magnification optical system, the reason why the above configuration is adopted and the operation thereof will be described. In order to correct lateral chromatic aberration and the like, it is preferable to arrange a positive lens in the first group. Therefore, by using this positive lens as 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.

  An eighth variable power optical system is the seventh variable power optical system, wherein at least one positive lens of the first group satisfies the following conditional expression.

0.1 mm ² <HH1 / φ1 <10 mm ² (1)
However, HH1: principal point interval of the first group positive lens,
φ1: refracting power of the first lens group positive lens,
It is.

  The reason why the above configuration is adopted in the eighth variable magnification optical system and the operation thereof will be described. When a negative lens is arranged closest to the object side 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.

0.5mm ² <HH1 / φ1 <5mm ² (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.
Further, the following conditional expression (1 ′) may be used.
^{0.1mm 2 <HH1 / φ1 ≦ 4.17mm} 2 ··· (1 ')

1 mm ² <HH1 / φ1 <2.5 mm ² (1-3)
A ninth variable power optical system is characterized in that, 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. .

  A ninth variable power optical system is characterized in that, 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. .

  The reason why the ninth variable power optical system has the above-described configuration 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.

  A tenth variable power optical system according to any one of the sixth to eighth variable power optical systems, wherein the at least one integral lens of the first group has at least one aspheric surface. is there.

  The reason why the tenth variable magnification optical system has the above configuration and the operation thereof will be described. At the wide-angle end of the above-described hysteretic variable optical system, 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.

  The eleventh variable power optical system is characterized in that, in the first to tenth variable power optical systems, the second group has at least one negative lens.

  In the eleventh variable magnification optical system, 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, fluctuations in various aberrations such as coma, astigmatism and axial chromatic aberration associated with zooming can be suppressed.

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

  In the thirteenth variable magnification optical system, 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.

  In a fourteenth variable magnification optical system, in the first to thirteenth variable magnification optical systems, the second group has at least one integrated lens, and at least one of the integrated lenses has a positive refractive power. It is characterized by having.

  The reason why the above-described configuration is adopted in the fourteenth variable magnification optical system 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.

  The fifteenth variable magnification optical system is the fourteenth variable magnification optical system, wherein at least one positive lens of the second group satisfies the following conditional expression.

0.1 mm ² <HH2 / φ2 <10 mm ² (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.

  The reason why the fifteenth variable magnification optical system has the above configuration 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 10 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.

0.5mm ² <HH2 / φ2 <5mm ² (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 mm ² <HH2 / φ2 <2.5 mm ² (2-3)
A sixteenth variable magnification optical system is characterized in that, in the fourteenth and fifteenth variable magnification optical systems, at least one of the integral lenses of the second group has at least one aspherical surface. is there.

  The reason why the above-described configuration is adopted in the sixteenth variable magnification optical system 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 aspherical surface in the second group, it is possible to satisfactorily correct variations in various aberrations such as spherical aberration and coma accompanying zooming with a smaller number of lenses. Therefore, it is possible to reduce the size and cost of the optical system.

  A seventeenth variable magnification optical system is characterized in that, in the first to sixteenth variable magnification optical systems, the third group has at least one integrated lens.

  The reason why the above-described configuration is adopted in the seventeenth variable magnification optical system and the operation thereof will be described. Since the third 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 third 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.

  The eighteenth variable magnification optical system is the seventeenth variable magnification optical system, wherein at least one of the integrated lenses is a positive lens having a positive refractive power.

  The reason why the above configuration is adopted in the eighteenth variable magnification optical system 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 and the overall length can be shortened. Moreover, since the positive lens of the third group has a large effective diameter, the volume of the optical material necessary for the lens also increases. Therefore, by making this positive lens an integral lens, the volume of the optical material is reduced. Therefore, cost can be reduced.

  A nineteenth variable magnification optical system is characterized in that, in the eighteenth variable magnification optical system, at least one positive lens of the third group satisfies the following conditional expression.

0.1 mm ² <HH3 / φ3 <20 mm ² (3)
However, HH3: principal point interval of the third group positive lens,
φ3: refractive power of the third lens group positive lens,
It is.

  The reason why the nineteenth variable magnification optical system has the above configuration and the operation thereof will be described. Increasing the power of the positive lens in the third group leads to increasing the power of the entire third group. By increasing the power of the third lens group positive lens, the following effects can be obtained. (1) Since the exit pupil position at the wide-angle end can be moved away from the image plane, it is easy to ensure image-side telecentricity. (2) When moving the third group along the optical axis direction during focusing, the moving range can be reduced. In this case, since the interval with the second group may be small, the overall length can be reduced.

  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. When the upper limit of 20 is exceeded, the power is smaller than the principal point interval, and the exit pupil position at the wide-angle end approaches the image plane. As a result, the image side telecentricity cannot be secured, which is not preferable.

  Furthermore, it is preferable that the following conditional expression (3-2) is satisfied. In this case, both shortening of the total lens length and downsizing of each lens can be achieved.

0.5 mm ² <HH3 / φ3 <9 mm ² (3-2)
Furthermore, it is more preferable to satisfy the following conditional expression (3-3). In this case, it is easier to achieve both shortening of the overall lens length and downsizing of each lens.

1 mm ² <HH3 / φ3 <4 mm ² (3-3)
The twentieth variable magnification optical system is characterized in that, in the seventeenth to nineteenth variable magnification optical systems, at least one of the integral lenses of the third group has at least one aspheric surface. is there.

  In the twentieth variable magnification optical system, the reason for adopting the above configuration and the operation thereof will be described. The variable magnification optical system of the above type has a large beam diameter in the third group at the wide angle end. Therefore, the third group includes at least one aspheric surface. By doing so, fluctuations in various aberrations such as spherical aberration and coma accompanying zooming can be favorably corrected with a smaller number of sheets. Therefore, it is possible to reduce the size and cost of the optical system.

  A twenty-first variable magnification optical system is characterized in that, in the first to twentieth variable magnification optical systems, the integrated lens is used in the four groups.

  The reason why the above configuration is adopted in the twenty-first variable magnification optical system 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.

  The twenty-second variable magnification optical system is the twenty-first variable magnification optical system, wherein at least one of the integrated lenses of the fourth group has at least one aspherical surface.

  In the twenty-second variable magnification optical system, the reason for adopting the above configuration and the operation thereof will be described. In the fourth group, the ray height is high. Therefore, by including at least one aspheric surface in the fourth group, off-axis aberrations such as distortion and astigmatism can be favorably corrected with a smaller number of sheets. Therefore, it is possible to reduce the size and cost of the optical system.

  The twenty-third variable power optical system is characterized in that, in the first to twenty-second variable power optical systems, the thinnest part thickness 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.

  The reason why the above-described configuration is adopted in the twenty-third variable magnification optical system 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)
The twenty-fourth variable magnification optical system is the twenty-third variable magnification optical system, wherein the integrated lens has a positive refractive power.

  The reason why the above-described configuration is adopted in the twenty-fourth variable magnification optical system and the operation thereof will be described. If the positive lens is an integral lens, the edge thickness of the positive lens can be reduced. Therefore, the total length can be shortened.

  The 25th variable power optical system is characterized in that, in the 1st to 24th variable power optical systems, when molding the integrated lens, a plurality of optical functional surfaces are simultaneously molded by a single molding machine. is there.

  The reason why the above-described configuration is adopted in the twenty-fifth zoom optical system 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.

  A twenty-sixth variable magnification optical system is the first to twenty-fifth variable magnification optical system, wherein the first material is glass.

  The reason for adopting the above configuration and the operation thereof in the twenty-sixth variable magnification optical system 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.

  A twenty-seventh variable power optical system is the first to twenty-sixth variable power optical system, wherein the second material has a light shielding property.

  The reason why the above configuration is adopted in the twenty-seventh variable magnification optical system 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.

  A twenty-eighth variable magnification optical system is the first to twenty-seventh variable magnification optical system, wherein the second material is metal, cermet, or ceramics.

  The reason why the above-described configuration is adopted in the twenty-eighth variable magnification optical system and the operation thereof 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.

  The twenty-ninth variable magnification optical system is characterized in that, in the first to twenty-eighth variable magnification optical systems, an organic-inorganic composite material is used as an optical material of at least one optical element constituting the optical system.

  The reason why the above-described configuration is adopted in the 29th variable magnification optical system 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.

  The 30th variable magnification optical system is the 29th variable magnification optical system, wherein the organic-inorganic composite includes zirconia nanoparticles.

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

  The thirty-second variable magnification optical system is the twenty-ninth variable magnification optical system, wherein the organic-inorganic composite includes niobium oxide nanoparticles.

  A thirty-third variable power optical system is the twenty-ninth variable power optical system, wherein the organic-inorganic composite includes a hydrolyzate of zirconium alkoxide and alumina nanoparticles.

  In the 30th to 33rd variable power optical systems, 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.

  An electronic apparatus using the above variable magnification optical system includes the first to thirty-third variable magnification optical systems and an electronic image pickup device arranged on the image side thereof.

  In this electronic apparatus, the reason why the above configuration is adopted and the operation thereof will be described. The above variable magnification optical system 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 convex portion 16 is provided on the upper pressing die 15 and pressed to simultaneously process the concave portion 17 on the second material 12. . 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, an aperture stop S, a second lens group G2, 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 moves along a concave locus on the object side, and at the telephoto end is located at substantially the same position as the wide-angle end, and the second lens group G2 Moves to the object side integrally with the aperture stop S, and the third lens group G3 and the fourth lens group G4 are fixed.

  The first lens group G1 has a negative power as a whole. The first lens group G1 includes, in order from the object side, a biconcave negative lens and a positive meniscus lens having a concave surface facing the image side. The aspheric surface is the image side surface of the biconcave negative 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 and the most object-side surface of the cemented lens.

  The third lens group G3 has positive power. The third lens group G3 is composed of a biconvex positive lens. The third lens group G3 moves in the direction of the optical axis only during focusing.

  The fourth lens group G4 has negative power. The fourth lens group G4 includes a negative meniscus lens having a convex surface directed toward the image side. The aspherical surface is a surface on the negative meniscus lens image side.

  All the lenses constituting the variable magnification optical system according to the present embodiment are integral lenses. 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 the second lens counted from the object side of the first lens group G1. In this lens, a positive meniscus lens is an integrated lens. Here, 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, a third lens group G3, and a fourth lens group G4. An aperture stop S is integrally disposed between the first lens and the second lens in the second lens group G2. When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves along a concave locus on the object side, and at the telephoto end is positioned at substantially the same position as the wide-angle end, and the second lens group G2 Moves to the object side integrally with the aperture stop S, and the third lens group G3 and the fourth lens group G4 are 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 second lens group G2 has a positive power as a whole. The second lens group G2 includes, in order from the object side, a positive meniscus lens having a concave surface directed to the image side, an aperture stop S, and a cemented lens of a biconvex positive lens and a biconcave negative lens. The aspheric surfaces are the object-side surface of the positive meniscus lens, the most object-side surface and the most image-side surface of the cemented lens.

  The third lens group G3 has positive power. The third lens group G3 is composed of a positive meniscus lens having a convex surface facing the image side. The third lens group G3 moves in the optical axis direction only during focusing.

  The fourth lens group G4 has negative power. The fourth lens group G4 includes a negative meniscus lens having a convex surface directed toward the image side. The aspherical surface is a surface on the negative meniscus lens image side.

  The lenses constituting the variable magnification optical system according to the present example are integral lenses except for the biconcave negative lens of the first lens group G1. 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 G1. In this cemented lens, the positive meniscus lens on the image side is the integrated lens 10. A biconcave negative lens is cemented to the object side. The thickness of the second material 12 is 0.3 mm. At this time, although not shown in FIG. 10, a hole or a concavo-convex shape may be simultaneously processed in the second material 12 during 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 expression, 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
Where r is a paraxial radius of curvature, K is a conical coefficient, and A ₄ , A ₆ , A ₈ , and A ₁₀ are 4th, 6th, 8th, and 10th order aspherical coefficients, respectively.

Example 1
r ₁ = -8.544 d ₁ = 0.60 n _d1 = 1.69350 ν _d1 = 53.21
r ₂ = 5.795 (aspherical surface) d ₂ = 0.44
r ₃ = 7.279 d ₃ = 0.67 n _d2 = 1.84666 ν _d2 = 23.78
r ₄ = 19.919 d ₄ = (variable)
r ₅ = ∞ (aperture) d ₅ = 0.10
r ₆ = 3.655 (aspherical surface) d ₆ = 1.38 n _d3 = 1.69350 ν _d3 = 53.21
r ₇ = -14.166 d ₇ = 0.10
r ₈ = 9.263 (aspherical surface) d ₈ = 0.99 n _d4 = 1.78800 ν _d4 = 47.37
r ₉ = -2.793 d ₉ = 0.60 n _d5 = 1.68893 ν _d5 = 31.07
r ₁₀ = 3.038 d ₁₀ = (variable)
r ₁₁ = 44.064 d ₁₁ = 1.60 n _d6 = 1.78800 ν _d6 = 47.37
r ₁₂ = -4.323 d ₁₂ = 0.16
r ₁₃ = -3.912 d ₁₃ = 1.60 n _d7 = 1.51633 ν _d7 = 64.14
r ₁₄ = -18.192 (aspherical surface) d ₁₄ = 0.10
r ₁₅ = ∞ d ₁₅ = 0.50 n _d8 = 1.51633 ν _d8 = 64.14
r ₁₆ = ∞
Aspheric coefficient 2nd surface K = -0.856
A ₄ = -5.31098 × 10 ^-4
A ₆ = 2.90922 × 10 ^-4
A ₈ = -6.35097 × 10 ^-5
A ₁₀ = 5.38366 × 10 ^-6
6th surface K = 0.057
A ₄ = -2.33967 × 10 ^-4
A ₆ = 6.09317 × 10 ^-6
A ₈ = 8.12573 × 10 ^-5
A ₁₀ = -1.66984 × 10 ^-5
8th surface K = -33.940
A ₄ = -1.48982 × 10 ^-3
A ₆ = -1.35589 × 10 ^-3
A ₈ = 0
A ₁₀ = 0
14th face K = 0.000
A ₄ = 7.17227 × 10 ^-3
A ₆ = -6.23670 × 10 ^-4
A ₈ = 0
A ₁₀ = 0
Zoom data (∞)
WE ST TE
f (mm) 4.4 6.2 8.8
F _NO 2.8 3.3 4.1
ω (°) 33.1 22.1 15.6
d ₄ 3.63 1.58 0.14
d ₁₀ 2.14 3.59 5.65.

Example 2
r ₁ = -6.328 d ₁ = 0.60 n _d1 = 1.69350 ν _d1 = 53.21
r ₂ = 3.092 d ₂ = 1.03 n _d2 = 1.81474 ν _d2 = 37.03
r ₃ = 11.872 d ₃ = (variable)
r ₄ = 3.024 (aspherical surface) d ₄ = 1.08 n _d3 = 1.69350 ν _d3 = 53.21
r ₅ = 36.382 d ₅ = 0.12
r ₆ = ∞ (aperture) d ₆ = 0.10
r ₇ = 4.427 (aspherical surface) d ₇ = 0.99 n _d4 = 1.78800 ν _d4 = 47.37
r ₈ = -7.290 d ₈ = 1.20 n _d5 = 1.84666 ν _d5 = 23.78
r ₉ = 3.680 (aspherical surface) d ₉ = (variable)
r ₁₀ = -7.523 d ₁₀ = 1.20 n _d6 = 1.80610 ν _d6 = 40.92
r ₁₁ = -2.849 d ₁₁ = 0.16
r ₁₂ = -2.632 d ₁₂ = 1.16 n _d7 = 1.49700 ν _d7 = 81.54
r ₁₃ = -6.396 (aspherical surface) d ₁₃ = 0.79
r ₁₄ = ∞ d ₁₄ = 0.50 n _d8 = 1.51633 ν _d8 = 64.14
r ₁₅ = ∞ d ₁₅ aspheric coefficient 4th surface K = 0.396
A ₄ = 2.09373 × 10 ^-3
A ₆ = -1.62524 × 10 ^-4
A ₈ = 2.20952 × 10 ^-4
A ₁₀ = -2.31731 × 10 ^-5
Surface 7 K = -8.236
A ₄ = 1.60630 × 10 ^-3
A ₆ = -3.38827 × 10 ^-3
A ₈ = -3.72604 × 10 ^-4
A ₁₀ = 0
The ninth side K = 0.344
A ₄ = 8.07095 × 10 ^-3
A ₆ = -7.93864 × 10 ^-4
A ₈ = 0
A ₁₀ = 0
Surface 13 K = 0.000
A ₄ = 3.88351 × 10 ^-3
A ₆ = -5.71375 × 10 ^-4
A ₈ = 0
A ₁₀ = 0
Zoom data (∞)
WE ST TE
f (mm) 4.4 6.2 8.8
F _NO 2.8 3.4 4.3
ω (°) 33.5 22.2 15.8
d ₃ 2.76 1.21 0.10
d ₉ 0.65 1.78 3.33.

Next, the values of conditional expressions (1) to (3) in each of the above-described embodiments will be shown (all are in mm ² ).

Example 1 Example 2
Conditional expression (1) 4.17 2.38
Conditional expression (2) (Object side lens) 2.32 2.11
(Image side lens) 1.17 1.50
Conditional expression (3) 3.50 3.07.

  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 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 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 unit 52 may be provided separately from the processing unit 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 positive refractive power, and a fourth group having a negative 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 has 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 mm ² <HH1 / φ1 <10 mm ² (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 mm ² <HH2 / φ2 <10 mm ² (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 set forth in [14] or [15], wherein at least one integral lens of the second group has at least one aspherical surface.

    [17] The zoom optical system according to any one of [1] to [16], wherein the third group includes at least one integrated lens.

    [18] The variable power optical system as described in 17 above, wherein at least one of the integral lenses is a positive lens having a positive refractive power.

    [19] The variable magnification optical system as described in 18 above, wherein at least one positive lens of the third group satisfies the following conditional expression:

0.1 mm ² <HH3 / φ3 <20 mm ² (3)
However, HH3: principal point interval of the third group positive lens,
φ3: refractive power of the third lens group positive lens,
It is.

    [20] The variable power optical system as set forth in any one of [17] to [19], wherein at least one integral lens of the third group has at least one aspherical surface.

    [21] The zoom optical system according to any one of [1] to [20], wherein the integrated lens is used in the four groups.

    [22] The variable power optical system as set forth in [21], wherein at least one integral lens of the fourth group has at least one aspherical surface.

    [23] The variable magnification optical system as set forth in any one of [1] to [22], wherein the thickness of the thinnest portion of at least one integral 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.

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

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

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

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

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

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

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

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

    [32] The variable magnification optical system as described in 29 above, wherein the organic-inorganic composite contains niobium oxide nanoparticles.

    [33] The variable power optical system as described in 29 above, wherein the organic-inorganic composite contains a hydrolyzate of zirconium alkoxide and nanoparticles of alumina.

    [34] An electronic apparatus comprising: the variable magnification optical system according to any one of 1 to 33 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. 3 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 integrated lens shape | molded by the manufacturing method of FIG. 8 at the array form. 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 formed in an array shape ... first material 12 ... second material 13 ... hole 14 formed in the second material ... lower die 15 of the molding die ... upper die 16 of the molding die ... convex shape Part 17 ... Concave part 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 (7)

In order from the object side, the first group having negative refractive power, the second group having positive refractive power, the third group having positive refractive power, and the fourth group having negative refractive power And
Upon zooming from the wide-angle end to the telephoto end movement, the first group moves in a concave locus toward the object side, located at the same position and the wide-angle end at the telephoto end, the second group to the object side The third group and the fourth group are fixed-magnification optical systems that are fixed,
The first group includes , in order from the object side, a biconcave negative lens and a positive meniscus lens having a concave surface facing the image side .
The second group is composed of, in order from the object side, a positive lens, and a cemented lens of a biconvex lens and a biconcave lens;
The third group includes a positive lens,
The fourth group is composed of a negative meniscus lens having a convex surface facing the image side,
At least one lens is molded using a first material that becomes a surface including at least an optical functional surface after molding, and a second material that becomes a surface other than the surface including at least an optical functional surface after molding. , Comprising an integrated lens in which the first material and the second material are integrated,
The first group includes at least one integrated lens, at least one of the integrated lenses has a positive refractive power, and the at least one positive lens satisfies the following conditional expression: Variable magnification optical system.
^{0.1mm 2 <HH1 / φ1 ≦ 4.17mm} 2 ··· (1 ')
However, HH1: principal point interval of the first group positive lens,
φ1: refracting power of the first lens group positive lens,
It is. The second group includes at least one integrated lens, at least one of the integrated lenses has a positive refractive power, and the at least one positive lens satisfies the following conditional expression: The variable magnification optical system according to claim 1.
0.1 mm ² <HH2 / φ2 <10 mm ² (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. The third group includes at least one integrated lens, and at least one of the integrated lenses is a positive lens having a positive refractive power, and the at least one positive lens satisfies the following conditional expression: The variable magnification optical system according to claim 1 or 2, characterized in that:
0.1 mm ² <HH3 / φ3 <20 mm ² (3)
However, HH3: principal point interval of the third group positive lens,
φ3: refractive power of the third lens group positive lens,
It is. The variable power optical system according to any one of claims 1 to 3, wherein the second material has a light shielding property. 5. The variable magnification optical system according to claim 1, wherein the second material is a metal, a cermet, or a ceramic. 6. The 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. An electronic apparatus comprising: the variable magnification optical system according to any one of claims 1 to 6; and an electronic image pickup device arranged on an image side thereof.

Images