WO2016017065A1 - Image pickup lens system and image pickup device - Google Patents

Image pickup lens system and image pickup device Download PDF

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Publication number
WO2016017065A1
WO2016017065A1 PCT/JP2015/003187 JP2015003187W WO2016017065A1 WO 2016017065 A1 WO2016017065 A1 WO 2016017065A1 JP 2015003187 W JP2015003187 W JP 2015003187W WO 2016017065 A1 WO2016017065 A1 WO 2016017065A1
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Prior art keywords
lens
lens group
lens system
imaging
image side
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PCT/JP2015/003187
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French (fr)
Japanese (ja)
Inventor
隆 杉山
隆 上高原
享博 下枝
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日立マクセル株式会社
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Publication of WO2016017065A1 publication Critical patent/WO2016017065A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/04—Reversed telephoto objectives
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/18—Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration

Definitions

  • the present invention relates to an imaging lens system and an imaging apparatus.
  • An optical system for monitoring is required to be a bright optical system having an extremely wide field of view, high resolution, and an F number of about 2.0.
  • an imaging lens system for a vehicle-mounted camera is also required to be compact.
  • Patent Document 1 describes, in order from the object side, an imaging lens system including a first lens having negative power, a second lens having positive power, a diaphragm, and a third lens having positive power.
  • This imaging lens system is composed of three lenses and has a wide angle and a small size.
  • Patent Document 2 in order from the object side, a first lens having a negative power, a second lens, a third lens having a positive power, an aperture, one of which has a positive power and the other has a negative power
  • An imaging lens system comprising a cemented lens having a positive power as a whole and a fourth lens having a positive power and a fourth lens having a positive power is described.
  • This imaging lens system has a wide angle, a small F number, and high resolution.
  • the imaging lens system described in Patent Document 1 is composed of three lenses, the half angle of view is a wide angle of 77.2 ° to 79.0 °, and the F number is 2.8. It is. However, an imaging lens system having a smaller F number and a high resolution is required as an optical system for monitoring applications.
  • the imaging lens system described in Patent Document 2 has a half angle of view as wide as 78.9 ° to 79.7 ° compared to the imaging lens system described in Patent Document 1, and the F number is 2. 0.0 and a high resolving power.
  • this imaging lens system is composed of six lenses, it is difficult to reduce the size and the cost is high.
  • the present invention has been made to solve the above-described problems, and an object thereof is to provide a wide-angle, bright, and compact imaging lens system.
  • the imaging lens system of the present invention is An imaging lens system comprising, in order from the object side, a first lens group having negative power, a second lens group having positive power, and a third lens group having positive power,
  • the first lens group includes one or two negative lenses
  • the second lens group is composed of one positive lens
  • the third lens group is composed of one positive lens
  • the focal length of the entire lens system is f
  • the focal length of the third lens group is f 3
  • the following conditional expression (1) is satisfied. 0.9 ⁇ f 3 /f ⁇ 2.2 (1)
  • the ratio of the focal length of the third lens group and the focal length of the entire lens system within the range of the conditional expression (1), the change in the focal position of the entire lens system with respect to the temperature change can be reduced. If the lower limit value of conditional expression (1) is not reached, the power of the third lens group becomes larger than the power of the entire lens system. At this time, the power of the first lens unit increases in order to keep the power of the entire lens system constant, and the balance of the focal position change with respect to the temperature change is lost, and the correction of the image plane becomes difficult. When the upper limit of conditional expression (1) is exceeded, the power of the third lens group becomes smaller than the power of the entire lens system. At this time, the power of the second lens unit is increased to keep the power of the entire lens system constant, and the balance of the focal position change with respect to the temperature change is lost, and the back focus is shortened, so that it is difficult to arrange the imaging device. Become.
  • an image pickup lens system wherein an image side lens surface of a most image side lens constituting the third lens group satisfies the following conditional expression (2). 0.9 ⁇ f L31R2 / f ⁇ 2.0 (2)
  • n Refractive index of the most image side lens constituting the third lens group
  • R Radius of curvature of the image side lens surface of the most image side lens constituting the third lens group
  • the change in the focal position with respect to the temperature change can be reduced.
  • the focal length of the image side lens surface of the third lens group becomes larger than the power of the entire lens system.
  • the power of the first lens unit increases in order to keep the power of the entire lens system constant, and the balance of the focal position change with respect to the temperature change is lost, and the correction of the image plane becomes difficult.
  • the power of the image side lens surface of the third lens group becomes smaller than the power of the entire lens system.
  • the power of the second lens unit is increased to keep the power of the entire lens system constant, and the balance of the focal position change with respect to the temperature change is lost, and the back focus is shortened, so that it is difficult to arrange the imaging device. Become.
  • the first lens group is preferably composed of one negative lens.
  • the first lens group preferably comprises two negative lenses.
  • the focal length of the first lens group is f 1
  • the focal length of the second lens group is f 2
  • a small imaging lens system can be realized by placing the ratio of the focal length of the first lens group and the focal length of the second lens group within the range of conditional expression (4). If the lower limit value of conditional expression (4) is not reached, the power of the first lens group increases, thereby increasing the back focus and increasing the overall length of the lens system. If the upper limit of conditional expression (4) is exceeded, the power of the first lens group decreases, the back focus is shortened, and the distance between the third lens group and the image sensor is shortened. It becomes difficult. In addition, since the incident angle of the light beam to the image sensor increases, the amount of light around the lens system decreases and the shading of the captured image increases.
  • the horizontal angle of view is preferably 100 degrees or more.
  • the stop be between the second lens group and the third lens group.
  • the imaging lens system of the present invention is An imaging lens system comprising, in order from the object side, a first lens group having negative power, a second lens group having positive power, and a third lens group having positive power,
  • the focal length of the entire lens system is f
  • the focal length of the third lens group is f 3
  • the following conditional expressions (1) and (2) are satisfied.
  • 0.9 ⁇ f 3 /f ⁇ 2.2 (1)
  • f L31R2 is the focal length of the image side lens surface of the most image side lens constituting the third lens group, and is defined by the following formula (3).
  • n Refractive index of the most image side lens constituting the third lens group
  • R Radius of curvature of the image side lens surface of the most image side lens constituting the third lens group
  • the imaging lens system of the present invention is An imaging lens system comprising, in order from the object side, a first lens group having negative power, a second lens group having positive power, and a third lens group having positive power,
  • the focal length of the entire lens system is f
  • the focal length of the first lens group is f 1
  • the focal length of the second lens group is f 2
  • the focal length of the third lens group is f 3
  • the following conditional expressions (1) and (4) are satisfied. 0.9 ⁇ f 3 /f ⁇ 2.2 (1) 0.3 ⁇
  • the stop be between the second lens group and the third lens group.
  • the imaging apparatus of the present invention The imaging lens system described above; And an image pickup device disposed at a focal position of the image pickup lens system.
  • a wide-angle, bright and small imaging lens system can be provided.
  • FIG. 1 is a cross-sectional view of an imaging lens system according to Example 1.
  • FIG. 4 is an aberration diagram of the imaging lens system according to Example 1.
  • FIG. 4 is an aberration diagram of the imaging lens system according to Example 1.
  • 6 is a cross-sectional view of an imaging lens system according to Example 2.
  • FIG. 6 is an aberration diagram of the imaging lens system according to Example 2.
  • FIG. 6 is an aberration diagram of the imaging lens system according to Example 2.
  • FIG. 6 is an aberration diagram of the imaging lens system according to Example 2.
  • FIG. 6 is an aberration diagram of the imaging lens system according to Example 2.
  • FIG. 6 is a cross-sectional view of an imaging lens system according to Example 3.
  • FIG. FIG. FIG. 1 is a cross-sectional view of an imaging lens system according to Example 1.
  • FIG. FIG. 4 is an aberration diagram of the imaging lens system according to Example 1.
  • FIG. 4 is an aberration diagram of the imaging lens system according to Example 1.
  • 6 is an aberration diagram of the imaging lens
  • FIG. 6 is an aberration diagram of the imaging lens system according to Example 3.
  • FIG. 6 is an aberration diagram of the imaging lens system according to Example 3.
  • FIG. 6 is an aberration diagram of the imaging lens system according to Example 3.
  • 6 is a cross-sectional view of an imaging lens system according to Example 4.
  • FIG. 10 is an aberration diagram of the imaging lens system according to Example 4.
  • FIG. 10 is an aberration diagram of the imaging lens system according to Example 4.
  • 6 is a cross-sectional view of an imaging lens system according to Example 5.
  • FIG. 10 is an aberration diagram of the imaging lens system according to Example 5.
  • FIG. 10 is an aberration diagram of the imaging lens system according to Example 5.
  • FIG. 10 is an aberration diagram of the imaging lens system according to Example 5.
  • FIG. 10 is an aberration diagram of the imaging lens system according to Example 5.
  • FIG. 10 is a cross-sectional view of an imaging lens system according to Example 6.
  • FIG. 10 is an aberration diagram of the imaging lens system according to Example 6.
  • FIG. 10 is an aberration diagram of the imaging lens system according to Example 6.
  • FIG. 10 is an aberration diagram of the imaging lens system according to Example 6.
  • FIG. 10 is an aberration diagram of the imaging lens system according to Example 6.
  • FIG. 2 is a diagram illustrating a configuration of the imaging lens system 101 according to the first embodiment.
  • the imaging lens system 101 according to the first exemplary embodiment includes, in order from the object side to the image side, a first lens group G1 having a negative power and a second lens group G2 having a positive power. And a stop STOP and a third lens group G3 having a positive power.
  • the first lens group G1 includes a lens L11.
  • the second lens group G2 includes a lens L21.
  • the third lens group G3 includes a lens L31.
  • the imaging plane of the imaging lens system 101 is indicated by IMG.
  • the lens L11, the lens L21, and the lens L31 are plastic lenses.
  • the lens L11 is an aspheric lens having negative power.
  • the object side lens surface S1 of the lens L11 is a spherical surface having a negative curvature
  • the image side lens surface S2 is an aspherical surface having a positive curvature.
  • the object side lens surface S1 has a concave surface facing the object side
  • the image side lens surface S2 has a convex curved surface portion protruding toward the object side.
  • the lens L21 is an aspheric lens having positive power.
  • the object side lens surface S3 is an aspherical surface having a positive curvature
  • the image side lens surface S4 is an aspherical surface having a positive curvature.
  • the object side lens surface S3 has a convex curved surface portion protruding toward the object side
  • the image side lens surface S4 has a convex curved surface portion protruding toward the object side.
  • the lens L31 is an aspheric lens having positive power.
  • the object side lens surface S6 is an aspherical surface having a negative curvature
  • the image side lens surface S7 is an aspherical surface having a negative curvature.
  • the object side lens surface S6 has a convex curved surface portion protruding toward the image side
  • the image side lens surface S7 has a convex curved surface portion protruding toward the image side.
  • Table 1 shows lens data of each lens surface of the imaging lens system 101.
  • the lens data includes the radius of curvature, surface spacing, refractive index, and Abbe number of each surface.
  • a surface marked with “*” indicates an aspherical surface.
  • the aspherical shape adopted for the lens surface is a first-order, second-order, third-order, fourth-order, where z is the sag amount, c is the reciprocal of the radius of curvature, k is the conic coefficient, and r is the height of the light beam from the optical axis.
  • z is the sag amount
  • c is the reciprocal of the radius of curvature
  • k is the conic coefficient
  • r is the height of the light beam from the optical axis.
  • Table 2 shows the aspheric coefficients for defining the aspherical shape of the aspherical lens surface in the imaging lens system 101 of Example 1.
  • “ ⁇ 6.522528E-03” means “ ⁇ 6.522528 ⁇ 10 ⁇ 3 ”.
  • 3A to 3C are a longitudinal aberration diagram, a field curvature diagram, and a distortion diagram of the imaging lens system 101 according to the first embodiment.
  • the half angle of view ⁇ is 80 ° and the F number is 2.0.
  • the horizontal axis indicates the position where the light beam intersects the optical axis Z
  • the vertical axis indicates the height at the pupil diameter.
  • the horizontal axis indicates the distance in the optical axis Z direction
  • the vertical axis indicates the image height (field angle).
  • FIG. 3B shows simulation results using light rays having a wavelength of 546 nm.
  • Table 3 shows the result of calculating the characteristic value of the imaging lens system 101 of Example 1.
  • the F number is FNo
  • the distance (optical total length) from the object-side lens surface S1 of the first lens L1 to the imaging surface IMG of the imaging lens system 101 is TL
  • the focal length of the entire lens system is f
  • the focal length of the first lens group G1 is f 1
  • the focal length of the second lens group G2 is f 2
  • the focal length of the third lens group G3 is f 3
  • the first lens group G1 and the second lens group G2 are combined.
  • FIG. 4 is a diagram illustrating a configuration of the imaging lens system 101 according to the second embodiment.
  • the imaging lens system 101 according to the second embodiment includes, in order from the object side to the image side, a first lens group G1 having a negative power and a second lens group G2 having a positive power. , And a third lens group G3 having a positive power.
  • the first lens group G1 includes a lens L11.
  • the second lens group G2 includes a lens L21.
  • the third lens group G3 includes a lens L31.
  • the lens L11 is a glass lens
  • the lenses L21 and L31 are plastic lenses.
  • the lens L11 is a spherical meniscus lens having negative power.
  • the object side lens surface S1 of the lens L11 is a spherical surface having a positive curvature
  • the image side lens surface S2 is a spherical surface having a positive curvature.
  • the object side lens surface S1 and the image side lens surface S2 are concave on the image side.
  • the lens L21 is an aspheric lens having positive power.
  • the object side lens surface S3 is an aspherical surface having a positive curvature
  • the image side lens surface S4 is an aspherical surface having a positive curvature.
  • the object side lens surface S3 has a convex curved surface portion protruding toward the object side
  • the image side lens surface S4 has a convex curved surface portion protruding toward the object side.
  • the lens L31 is an aspheric lens having positive power.
  • the object side lens surface S6 is an aspherical surface having a negative curvature
  • the image side lens surface S7 is an aspherical surface having a negative curvature.
  • the object side lens surface S6 has a convex curved surface portion protruding toward the image side
  • the image side lens surface S7 has a convex curved surface portion protruding toward the image side.
  • Table 4 shows lens data of each lens surface of the imaging lens system 101.
  • a surface marked with “*” indicates an aspherical surface.
  • Table 5 shows the aspherical coefficients for defining the aspherical shape of the aspherical lens surface in the imaging lens system 101 of Example 2.
  • FIGS. 5A to 5C are a longitudinal aberration diagram, a field curvature diagram, and a distortion diagram of the imaging lens system 101 of the second embodiment.
  • the half angle of view ⁇ is 80 ° and the F number is 2.0.
  • the horizontal axis indicates the position where the light beam intersects the optical axis Z
  • the vertical axis indicates the height at the pupil diameter.
  • the horizontal axis indicates the distance in the optical axis Z direction
  • the vertical axis indicates the image height (field angle).
  • FIG. 5B shows simulation results using light rays having a wavelength of 546 nm.
  • Table 6 shows the results of calculating the characteristic values of the imaging lens system 101 of Example 2. Table 6 shows the results calculated for the same characteristic values as in Table 3.
  • FIG. 6 is a diagram illustrating a configuration of the imaging lens system 101 according to the third embodiment.
  • the imaging lens system 101 according to the third exemplary embodiment includes, in order from the object side to the image side, a first lens group G1 having a negative power, a second lens group G2 having a positive power, a diaphragm, and a positive power. And a third lens group G3.
  • the first lens group G1 includes a lens L11 and a lens L12.
  • the second lens group G2 includes a lens L21.
  • the third lens group G3 includes a lens L31.
  • the lens L11 is a glass lens
  • the lens L12, the lens L21, and the lens L31 are plastic lenses.
  • the lens L11 is a spherical meniscus lens having negative power.
  • the object side lens surface S1 of the lens L11 is a spherical surface having a positive curvature
  • the image side lens surface S2 is a spherical surface having a positive curvature.
  • the object side lens surface S1 and the image side lens surface S2 are concave on the image side.
  • Lens L12 is an aspherical lens having negative power.
  • the object side lens surface S3 of the lens L12 is an aspheric surface having a negative curvature
  • the image side lens surface S4 is an aspheric surface having a positive curvature.
  • the object side lens surface S3 has a convex curved surface portion protruding toward the image side
  • the image side lens surface S4 has a convex curved surface portion protruding toward the object side.
  • the lens L21 is an aspheric lens having positive power.
  • the object side lens surface S5 is an aspherical surface having a positive curvature
  • the image side lens surface S6 is an aspherical surface having a positive curvature.
  • the object side lens surface S5 has a convex curved surface portion protruding toward the object side
  • the image side lens surface S6 has a convex curved surface portion protruding toward the object side.
  • the lens L31 is an aspheric lens having positive power.
  • the object side lens surface S8 is an aspherical surface having a positive curvature
  • the image side lens surface S9 is an aspherical surface having a negative curvature.
  • the object side lens surface S8 has a convex curved surface portion protruding toward the object side
  • the image side lens surface S9 has a convex curved surface portion protruding toward the image side.
  • Table 7 shows lens data of each lens surface of the imaging lens system 101.
  • a surface marked with “*” indicates an aspherical surface.
  • the aspherical shape adopted for the lens surfaces of the lens L21 and the lens L31 is expressed by the mathematical formula described in the first embodiment.
  • the aspherical shape adopted for the lens surface of the lens L12 is 4th order, 6th order, 8th order, where z is the sag amount, c is the reciprocal of the radius of curvature, k is the cone coefficient, and r is the height of the light beam from the optical axis.
  • the 10th-order, 12th-order, 14th-order, and 16th-order aspherical coefficients are ⁇ 4, ⁇ 6, ⁇ 8, ⁇ 10, ⁇ 12, and ⁇ 14, respectively, they are expressed by the following equations.
  • Table 8 shows aspherical coefficients for defining the aspherical shape of the aspherical lens surface in the imaging lens system 101 of Example 3.
  • FIGS. 7A to 7C are a longitudinal aberration diagram, a field curvature diagram, and a distortion diagram of the imaging lens system 101 of Example 3.
  • FIG. As shown in FIGS. 7A to 7C, in the imaging lens system 101 of Example 3, the half angle of view ⁇ is 89 ° and the F number is 2.0.
  • the horizontal axis indicates the position where the light beam intersects the optical axis Z, and the vertical axis indicates the height at the pupil diameter.
  • the horizontal axis indicates the distance in the optical axis Z direction
  • the vertical axis indicates the image height (field angle).
  • Table 9 shows the results of calculating the characteristic values of the imaging lens system 101 of Example 3.
  • the F number is FNo
  • the distance from the object-side lens surface S1 of the first lens L11 to the imaging surface IMG of the imaging lens system 101 is TL
  • the focal length of the entire lens system is f
  • focal length f 1 of the first lens group G1 the focal length f 2 of the second lens group G2
  • the focal length f 3 of the third lens group G3 the focal distance f L11 of the lens L11, the focal length of the lens L12 F L12
  • the combined focal length of the first lens group G1 and the second lens group G2 is f 12
  • the combined focal length of the second lens group G2 and the third lens group G3 is f 23
  • the lens L12 and the lens L21 combined focal distance of the composite focal distance f L12L21, a composite focal length of the lens L11 and the lens L12 and the lens L21 and f L11L21, lens L12 and a lens L21 and lens
  • FIG. 8 is a diagram illustrating a configuration of the imaging lens system 101 according to the fourth embodiment.
  • the imaging lens system 101 according to the fourth exemplary embodiment includes, in order from the object side to the image side, a first lens group G1 having a negative power, a second lens group G2 having a positive power, a diaphragm, and a positive power. And a third lens group G3.
  • the first lens group G1 includes a lens L11 and a lens L12.
  • the second lens group G2 includes a lens L21.
  • the third lens group G3 includes a lens L31.
  • the lens L11 is a glass lens
  • the lens L12, the lens L21, and the lens L31 are plastic lenses.
  • the lens L11 is a spherical meniscus lens having negative power.
  • the object side lens surface S1 of the lens L11 is a spherical surface having a positive curvature
  • the image side lens surface S2 is a spherical surface having a positive curvature.
  • the object side lens surface S1 and the image side lens surface S2 are concave on the image side.
  • Lens L12 is an aspherical lens having negative power.
  • the object side lens surface S3 of the lens L12 is an aspheric surface having a negative curvature
  • the image side lens surface S4 is an aspheric surface having a positive curvature.
  • the object side lens surface S3 has a convex curved surface portion protruding toward the image side
  • the image side lens surface S4 has a convex curved surface portion protruding toward the object side.
  • the lens L21 is an aspheric lens having positive power.
  • the object side lens surface S5 is an aspherical surface having a positive curvature
  • the image side lens surface S6 is an aspherical surface having a positive curvature.
  • the object side lens surface S5 has a convex curved surface portion protruding toward the object side
  • the image side lens surface S6 has a convex curved surface portion protruding toward the object side.
  • the lens L31 is an aspheric lens having positive power.
  • the object side lens surface S8 is an aspherical surface having a positive curvature
  • the image side lens surface S9 is an aspherical surface having a negative curvature.
  • the object side lens surface S8 has a convex curved surface portion protruding toward the object side
  • the image side lens surface S9 has a convex curved surface portion protruding toward the image side.
  • Table 10 shows lens data of each lens surface of the imaging lens system 101.
  • a surface marked with “*” indicates an aspherical surface.
  • Table 11 shows the aspheric coefficients for defining the aspheric shape of the aspheric lens surface in the imaging lens system 101 of Example 4.
  • FIGS. 9A to 9C are a longitudinal aberration diagram, a field curvature diagram, and a distortion diagram of the imaging lens system 101 of Example 4.
  • FIG. 9A to 9C in the imaging lens system 101 of Example 4, the half angle of view ⁇ is 89 ° and the F number is 2.0.
  • the horizontal axis indicates the position where the light beam intersects the optical axis Z
  • the vertical axis indicates the height at the pupil diameter.
  • the horizontal axis indicates the distance in the optical axis Z direction
  • the vertical axis indicates the image height (field angle).
  • FIG. 9B shows simulation results using light rays having a wavelength of 546 nm.
  • Table 12 shows the result of calculating the characteristic values of the imaging lens system 101 of Example 4.
  • Table 12 shows the calculation results for the same characteristic values as in Table 9.
  • FIG. 10 is a diagram illustrating a configuration of the imaging lens system 101 according to the fifth embodiment.
  • the imaging lens system 101 according to the fifth exemplary embodiment includes, in order from the object side to the image side, a first lens group G1 having a negative power, a second lens group G2 having a positive power, a diaphragm, and a positive power. And a third lens group G3.
  • the first lens group G1 includes a lens L11 and a lens L12.
  • the second lens group G2 includes a lens L21.
  • the third lens group G3 includes a lens L31.
  • the lens L11 is a glass lens
  • the lens L12, the lens L21, and the lens L31 are plastic lenses.
  • the lens L11 is a spherical meniscus lens having negative power.
  • the object side lens surface S1 of the lens L11 is a spherical surface having a positive curvature
  • the image side lens surface S2 is a spherical surface having a positive curvature.
  • the object side lens surface S1 and the image side lens surface S2 are concave on the image side.
  • Lens L12 is an aspherical lens having negative power.
  • the object side lens surface S3 of the lens L12 is an aspheric surface having a negative curvature
  • the image side lens surface S4 is an aspheric surface having a positive curvature.
  • the object side lens surface S3 has a convex curved surface portion protruding toward the image side
  • the image side lens surface S4 has a convex curved surface portion protruding toward the object side.
  • the lens L21 is an aspheric lens having positive power.
  • the object side lens surface S5 is an aspherical surface having a positive curvature
  • the image side lens surface S6 is an aspherical surface having a positive curvature.
  • the object side lens surface S5 has a convex curved surface portion protruding toward the object side
  • the image side lens surface S6 has a convex curved surface portion protruding toward the object side.
  • the lens L31 is an aspheric lens having positive power.
  • the object side lens surface S8 is an aspherical surface having a negative curvature
  • the image side lens surface S9 is an aspherical surface having a negative curvature.
  • the object side lens surface S8 has a convex curved surface portion protruding toward the image side
  • the image side lens surface S9 has a convex curved surface portion protruding toward the image side.
  • Table 13 shows lens data of each lens surface of the imaging lens system 101.
  • a surface marked with “*” indicates an aspherical surface.
  • Table 14 shows the aspherical coefficients for defining the aspherical shape of the aspherical lens surface in the imaging lens system 101 of Example 5.
  • FIGS. 11A to 11C are a longitudinal aberration diagram, a field curvature diagram, and a distortion diagram of the imaging lens system 101 of Example 5.
  • FIG. 11A to 11C in the imaging lens system 101 of Example 5, the half angle of view ⁇ is 107 ° and the F number is 2.0.
  • the horizontal axis indicates the position where the light beam intersects the optical axis Z
  • the vertical axis indicates the height at the pupil diameter.
  • the horizontal axis indicates the distance in the optical axis Z direction
  • the vertical axis indicates the image height (field angle).
  • FIG. 11B shows simulation results using light rays having a wavelength of 546 nm.
  • Table 15 shows the results of calculating the characteristic values of the imaging lens system 101 of Example 5. Table 15 shows the results calculated for the same characteristic values as in Table 9.
  • FIG. 12 is a diagram illustrating a configuration of the imaging lens system 101 according to the sixth embodiment.
  • the imaging lens system 101 according to the sixth exemplary embodiment includes, in order from the object side to the image side, a first lens group G1 having a negative power, a second lens group G2 having a positive power, a diaphragm, and a positive power. And a third lens group G3.
  • the first lens group G1 includes a lens L11 and a lens L12.
  • the second lens group G2 includes a lens L21.
  • the third lens group G3 includes a lens L31.
  • the lens L11 is a glass lens
  • the lens L12, the lens L21, and the lens L31 are plastic lenses.
  • the lens L11 is a spherical meniscus lens having negative power.
  • the object side lens surface S1 of the lens L11 is a spherical surface having a positive curvature
  • the image side lens surface S2 is a spherical surface having a positive curvature.
  • the object side lens surface S1 and the image side lens surface S2 are concave on the image side.
  • Lens L12 is an aspherical lens having negative power.
  • the object side lens surface S3 of the lens L12 is an aspheric surface having a negative curvature
  • the image side lens surface S4 is an aspheric surface having a positive curvature.
  • the object side lens surface S3 has a convex curved surface portion protruding toward the image side
  • the image side lens surface S4 has a convex curved surface portion protruding toward the object side.
  • the lens L21 is an aspheric lens having positive power.
  • the object side lens surface S5 is an aspherical surface having a positive curvature
  • the image side lens surface S6 is an aspherical surface having a positive curvature.
  • the object side lens surface S5 has a convex curved surface portion protruding toward the object side
  • the image side lens surface S6 has a convex curved surface portion protruding toward the object side.
  • the lens L31 is an aspheric lens having positive power.
  • the object side lens surface S8 is an aspherical surface having a negative curvature
  • the image side lens surface S9 is an aspherical surface having a negative curvature.
  • the object side lens surface S8 has a convex curved surface portion protruding toward the image side
  • the image side lens surface S9 has a convex curved surface portion protruding toward the image side.
  • Table 16 shows lens data of each lens surface of the imaging lens system 101.
  • a surface marked with “*” indicates an aspherical surface.
  • Table 17 shows the aspherical coefficients for defining the aspherical shape of the aspherical lens surface in the imaging lens system 101 of Example 6.
  • FIGS. 13A to 13C are a longitudinal aberration diagram, a field curvature diagram, and a distortion diagram of the imaging lens system 101 of Example 6.
  • FIG. 13A to 13C in the imaging lens system 101 of Example 6, the half angle of view ⁇ is 109 ° and the F number is 2.0.
  • the horizontal axis indicates the position where the light beam intersects the optical axis Z
  • the vertical axis indicates the height at the pupil diameter.
  • the horizontal axis indicates the distance in the optical axis Z direction
  • the vertical axis indicates the image height (field angle).
  • FIG. 13B shows simulation results using light rays having a wavelength of 546 nm.
  • Table 18 shows the result of calculating the characteristic values of the imaging lens system 101 of Example 6. Table 18 shows the results calculated for the same characteristic values as in Table 9.
  • Table 19 shows the results of calculating the parameters of conditional expressions (1), (2), and (4) in the imaging lens systems 101 of Examples 1 to 6.
  • FIG. 1 is a diagram illustrating a configuration of an imaging apparatus 100 using an imaging lens system 101.
  • the imaging apparatus 100 includes an imaging lens system 101, a cover glass 102, and an imaging element 103.
  • the imaging lens system 101, the cover glass 102, and the imaging element 103 are accommodated in a housing (not shown).
  • the image sensor 103 is an element that converts received light into an electrical signal.
  • a CCD image sensor or a CMOS image sensor is used.
  • the image sensor 103 is disposed at the imaging position of the imaging lens system 101.
  • the horizontal angle of view is an angle of view corresponding to the horizontal direction of the image sensor 103.
  • the cover glass 102 is provided on the image sensor 103 in order to protect the image sensor 103 from foreign matter.
  • the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention.
  • the application of the imaging lens system 101 of the present invention is not limited to an in-vehicle camera or a surveillance camera, and can be used for other applications such as mounting in a small electronic device such as a mobile phone.

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Abstract

Provided is an image pickup lens system that is wide angle, bright, and miniature. This image pickup lens system (101) comprises, in order from the object side, the following: a negative-power first lens group (G1); a positive-power second lens group (G2); and a positive-power third lens group (G3). The first lens group (G1) comprises one or two negative lenses, the second lens group (G2) comprises one positive lens, and the third lens group (G3) comprises one positive lens. The present invention is characterized in that, when the focal length of the entire lens system is f, and the focal length of the third lens group is f3, formula (1) is satisfied. (1): 0.8<f3/f<1.5

Description

撮像レンズ系及び撮像装置Imaging lens system and imaging apparatus
　本発明は、撮像レンズ系及び撮像装置に関する。 The present invention relates to an imaging lens system and an imaging apparatus.
　監視用途の光学系として、屋内外の安全性を確保する監視カメラ用レンズ系、車外及び車内監視用の車載カメラ用レンズ系などがある。監視用途の光学系には、視界が極めて広く、かつ、高い解像力を有するとともに、さらに、Ｆナンバが２．０程度の明るい光学系であることが求められる。また、特に、車載カメラ用の撮像レンズ系では、コンパクトさも求められる。 There are a monitoring camera lens system for ensuring safety indoors and outdoors, and an in-vehicle camera lens system for monitoring outside and inside the vehicle. An optical system for monitoring is required to be a bright optical system having an extremely wide field of view, high resolution, and an F number of about 2.0. In particular, an imaging lens system for a vehicle-mounted camera is also required to be compact.
　特許文献１には、物体側から順に、負のパワーを有する第１レンズ、正のパワーを有する第２レンズ、絞り、正のパワーを有する第３レンズからなる撮像レンズ系が記載されている。この撮像レンズ系は、レンズ３枚から構成され、広角かつ小型である。 Patent Document 1 describes, in order from the object side, an imaging lens system including a first lens having negative power, a second lens having positive power, a diaphragm, and a third lens having positive power. This imaging lens system is composed of three lenses and has a wide angle and a small size.
　特許文献２には、物体側から順に、負のパワーを有する第１レンズ、第２レンズ、正のパワーを有する第３レンズ、絞り、いずれか一方が正のパワーを有し他方が負のパワーを有する第４レンズ及び第５レンズを接合してなり全体として正のパワーを有する接合レンズと、正のパワーを有する第６レンズからなる撮像レンズ系が記載されている。この撮像レンズ系は、広角で、Ｆナンバが小さく、かつ高解像力を有する。 In Patent Document 2, in order from the object side, a first lens having a negative power, a second lens, a third lens having a positive power, an aperture, one of which has a positive power and the other has a negative power An imaging lens system comprising a cemented lens having a positive power as a whole and a fourth lens having a positive power and a fourth lens having a positive power is described. This imaging lens system has a wide angle, a small F number, and high resolution.
特許５３９３５２１号公報Japanese Patent No. 5393521 特許５０４２７６７号公報Japanese Patent No. 5042767
　特許文献１に記載の撮像レンズ系は、レンズ３枚で構成されているにも関わらず、半画角が７７．２°～７９．０°と広角であり、かつ、Ｆナンバが２．８である。しかし、監視用途の光学系として、より小さいＦナンバを有し、かつ、高解像力の撮像レンズ系が求められている。 Although the imaging lens system described in Patent Document 1 is composed of three lenses, the half angle of view is a wide angle of 77.2 ° to 79.0 °, and the F number is 2.8. It is. However, an imaging lens system having a smaller F number and a high resolution is required as an optical system for monitoring applications.
　特許文献２に記載の撮像レンズ系は、特許文献１に記載の撮像レンズ系と比較して、半画角が７８．９°～７９．７°と同程度に広角であり、Ｆナンバが２．０と小さく、かつ、解像力が高い。しかし、この撮像レンズ系は、６枚のレンズからなるため、小型化が難しく、高コストであった。 The imaging lens system described in Patent Document 2 has a half angle of view as wide as 78.9 ° to 79.7 ° compared to the imaging lens system described in Patent Document 1, and the F number is 2. 0.0 and a high resolving power. However, since this imaging lens system is composed of six lenses, it is difficult to reduce the size and the cost is high.
　本発明は、上述の問題を解決するためなされたものであり、広角で、明るく、かつ、小型の撮像レンズ系を提供することを目的とする。 The present invention has been made to solve the above-described problems, and an object thereof is to provide a wide-angle, bright, and compact imaging lens system.
　本発明の撮像レンズ系は、
　物体側から順に、負のパワーを有する第１レンズ群、正のパワーを有する第２レンズ群、正のパワーを有する第３レンズ群とからなる撮像レンズ系であって、
　前記第１レンズ群は１枚又は２枚の負レンズからなり、
　前記第２レンズ群は１枚の正レンズからなり、
　前記第３レンズ群は１枚の正レンズからなり、
　レンズ系全体の焦点距離をｆ、
　前記第３レンズ群の焦点距離をｆ３、
　としたときに、下記の条件式（１）を満たすことを特徴とする。
　０．９＜ｆ３／ｆ＜２．２　　（１） The imaging lens system of the present invention is
An imaging lens system comprising, in order from the object side, a first lens group having negative power, a second lens group having positive power, and a third lens group having positive power,
The first lens group includes one or two negative lenses,
The second lens group is composed of one positive lens,
The third lens group is composed of one positive lens,
The focal length of the entire lens system is f,
The focal length of the third lens group is f 3 ,
The following conditional expression (1) is satisfied.
0.9 <f 3 /f<2.2 (1)
　第３レンズ群の焦点距離とレンズ系全体の焦点距離との比を条件式（１）の範囲内に置くことにより、温度変化に対するレンズ系全体の焦点位置の変化を小さくできる。条件式（１）の下限値を下回ると、第３レンズ群のパワーがレンズ系全体のパワーに対して大きくなる。このとき、レンズ系全体のパワーを一定に保つために第１レンズ群のパワーが増大し、温度変化に対する焦点位置変化のバランスが崩れるとともに、像面の補正が困難になる。条件式（１）の上限値を超えると、第３レンズ群のパワーがレンズ系全体のパワーに対して小さくなる。このとき、レンズ系全体のパワーを一定に保つために第２レンズ群のパワーが増大し、温度変化に対する焦点位置変化のバランスが崩れるとともに、バックフォーカスが短くなるため撮像素子を配置するのが難しくなる。 By placing the ratio of the focal length of the third lens group and the focal length of the entire lens system within the range of the conditional expression (1), the change in the focal position of the entire lens system with respect to the temperature change can be reduced. If the lower limit value of conditional expression (1) is not reached, the power of the third lens group becomes larger than the power of the entire lens system. At this time, the power of the first lens unit increases in order to keep the power of the entire lens system constant, and the balance of the focal position change with respect to the temperature change is lost, and the correction of the image plane becomes difficult. When the upper limit of conditional expression (1) is exceeded, the power of the third lens group becomes smaller than the power of the entire lens system. At this time, the power of the second lens unit is increased to keep the power of the entire lens system constant, and the balance of the focal position change with respect to the temperature change is lost, and the back focus is shortened, so that it is difficult to arrange the imaging device. Become.
　本発明では、
　前記第３レンズ群を構成する最も像側のレンズの像側レンズ面は、下記の条件式（２）を満たすことを特徴とする撮像レンズ系。
０．９＜ｆＬ３１Ｒ２／ｆ＜２．０　　（２）
　ただし、ｆＬ３１Ｒ２は第３レンズ群を構成する最も像側のレンズの像側レンズ面の焦点距離であり、以下の式（３）で定義されることが好ましい。
　１／ｆＬ３１Ｒ２＝－（ｎ－１）／Ｒ　　（３）
ｎ：第３レンズ群を構成する最も像側のレンズの屈折率
Ｒ：第３レンズ群を構成する最も像側のレンズの像側レンズ面の曲率半径 In the present invention,
An image pickup lens system, wherein an image side lens surface of a most image side lens constituting the third lens group satisfies the following conditional expression (2).
0.9 <f L31R2 / f <2.0 (2)
However, f L31R2 is the focal length of the image side lens surface of the most image side lens constituting the third lens group, and is preferably defined by the following formula (3).
1 / f L31R2 = − (n−1) / R (3)
n: Refractive index of the most image side lens constituting the third lens group R: Radius of curvature of the image side lens surface of the most image side lens constituting the third lens group
　第３レンズ群の像側レンズ面（Ｒ２面）の正のパワーを大きくすることにより、温度変化に対する焦点位置の変化を小さくできる。条件式（２）の下限値を下回ると、第３レンズ群の像側レンズ面の焦点距離がレンズ系全体のパワーに対して大きくなる。このとき、レンズ系全体のパワーを一定に保つために第１レンズ群のパワーが増大し、温度変化に対する焦点位置変化のバランスが崩れるとともに、像面の補正が困難になる。条件式（２）の上限値を超えると、第３レンズ群の像側レンズ面のパワーがレンズ系全体のパワーに対して小さくなる。このとき、レンズ系全体のパワーを一定に保つために第２レンズ群のパワーが増大し、温度変化に対する焦点位置変化のバランスが崩れるとともに、バックフォーカスが短くなるため撮像素子を配置するのが難しくなる。 By increasing the positive power of the image side lens surface (R2 surface) of the third lens group, the change in the focal position with respect to the temperature change can be reduced. If the lower limit value of conditional expression (2) is not reached, the focal length of the image side lens surface of the third lens group becomes larger than the power of the entire lens system. At this time, the power of the first lens unit increases in order to keep the power of the entire lens system constant, and the balance of the focal position change with respect to the temperature change is lost, and the correction of the image plane becomes difficult. When the upper limit value of conditional expression (2) is exceeded, the power of the image side lens surface of the third lens group becomes smaller than the power of the entire lens system. At this time, the power of the second lens unit is increased to keep the power of the entire lens system constant, and the balance of the focal position change with respect to the temperature change is lost, and the back focus is shortened, so that it is difficult to arrange the imaging device. Become.
　本発明では、
　前記第１レンズ群は１枚の負レンズからなる
　ことが好ましい。 In the present invention,
The first lens group is preferably composed of one negative lens.
　また、本発明では、
　前記第１レンズ群は２枚の負レンズからなる
　ことが好ましい。 In the present invention,
The first lens group preferably comprises two negative lenses.
　本発明では、
　前記第１レンズ群の焦点距離をｆ１、
　前記第２レンズ群の焦点距離をｆ２、
　としたときに、下記の条件式（４）を満たすことが好ましい。
　０．３＜｜ｆ１／ｆ２｜＜１．５　　（４） In the present invention,
The focal length of the first lens group is f 1 ,
The focal length of the second lens group is f 2 ,
It is preferable that the following conditional expression (4) is satisfied.
0.3 <| f 1 / f 2 | <1.5 (4)
　第１レンズ群の焦点距離と第２レンズ群の焦点距離との比を条件式（４）の範囲内に置くことにより、小型の撮像レンズ系を実現できる。条件式（４）の下限値を下回ると、第１レンズ群のパワーが増大することにより、バックフォーカスが増大してレンズ系の全長増大につながる。条件式（４）の上限値を上回ると、第１レンズ群のパワーが減少することにより、バックフォーカスが短くなり、第３レンズ群と撮像素子との距離が短くなるため、撮像素子の配置が難しくなる。また、撮像素子への光線の入射角が増大するため、レンズ系の周辺光量が低下し、撮像画像のシェーディングが大きくなる。 A small imaging lens system can be realized by placing the ratio of the focal length of the first lens group and the focal length of the second lens group within the range of conditional expression (4). If the lower limit value of conditional expression (4) is not reached, the power of the first lens group increases, thereby increasing the back focus and increasing the overall length of the lens system. If the upper limit of conditional expression (4) is exceeded, the power of the first lens group decreases, the back focus is shortened, and the distance between the third lens group and the image sensor is shortened. It becomes difficult. In addition, since the incident angle of the light beam to the image sensor increases, the amount of light around the lens system decreases and the shading of the captured image increases.
　本発明では、
　水平画角が１００度以上である
　ことが好ましい。 In the present invention,
The horizontal angle of view is preferably 100 degrees or more.
　本発明では、
　絞りが前記第２レンズ群と前記第３レンズ群との間にある
　ことが好ましい。 In the present invention,
It is preferable that the stop be between the second lens group and the third lens group.
　本発明の撮像レンズ系は、
　物体側から順に、負のパワーを有する第１レンズ群、正のパワーを有する第２レンズ群、正のパワーを有する第３レンズ群とからなる撮像レンズ系であって、
　レンズ系全体の焦点距離をｆ、
　前記第３レンズ群の焦点距離をｆ３、
　としたときに、下記の条件式（１）及び（２）を満たすことを特徴とする。
　０．９＜ｆ３／ｆ＜２．２　　（１）
　０．９＜ｆＬ３１Ｒ２／ｆ＜２．０　　（２）
　ただし、ｆＬ３１Ｒ２は第３レンズ群を構成する最も像側のレンズの像側レンズ面の焦点距離であり、以下の式（３）で定義される。
　１／ｆＬ３１Ｒ２＝－（ｎ－１）／Ｒ　　（３）
ｎ：第３レンズ群を構成する最も像側のレンズの屈折率
Ｒ：第３レンズ群を構成する最も像側のレンズの像側レンズ面の曲率半径 The imaging lens system of the present invention is
An imaging lens system comprising, in order from the object side, a first lens group having negative power, a second lens group having positive power, and a third lens group having positive power,
The focal length of the entire lens system is f,
The focal length of the third lens group is f 3 ,
The following conditional expressions (1) and (2) are satisfied.
0.9 <f 3 /f<2.2 (1)
0.9 <f L31R2 / f <2.0 (2)
Here, f L31R2 is the focal length of the image side lens surface of the most image side lens constituting the third lens group, and is defined by the following formula (3).
1 / f L31R2 = − (n−1) / R (3)
n: Refractive index of the most image side lens constituting the third lens group R: Radius of curvature of the image side lens surface of the most image side lens constituting the third lens group
　本発明の撮像レンズ系は、
　物体側から順に、負のパワーを有する第１レンズ群、正のパワーを有する第２レンズ群、正のパワーを有する第３レンズ群とからなる撮像レンズ系であって、
　レンズ系全体の焦点距離をｆ、
　前記第１レンズ群の焦点距離をｆ１、
　前記第２レンズ群の焦点距離をｆ２、
　前記第３レンズ群の焦点距離をｆ３、
　としたときに、下記の条件式（１）及び（４）を満たすことを特徴とする。
　０．９＜ｆ３／ｆ＜２．２　　（１）
　０．３＜｜ｆ１／ｆ２｜＜１．５　　（４） The imaging lens system of the present invention is
An imaging lens system comprising, in order from the object side, a first lens group having negative power, a second lens group having positive power, and a third lens group having positive power,
The focal length of the entire lens system is f,
The focal length of the first lens group is f 1 ,
The focal length of the second lens group is f 2 ,
The focal length of the third lens group is f 3 ,
The following conditional expressions (1) and (4) are satisfied.
0.9 <f 3 /f<2.2 (1)
0.3 <| f 1 / f 2 | <1.5 (4)
　本発明では、
　絞りが前記第２レンズ群と前記第３レンズ群との間にある
　ことが好ましい。 In the present invention,
It is preferable that the stop be between the second lens group and the third lens group.
　本発明の撮像装置は、
　上述の撮像レンズ系と、
　前記撮像レンズ系の焦点位置に配置された撮像素子と、を有する
　ことを特徴とする。 The imaging apparatus of the present invention
The imaging lens system described above;
And an image pickup device disposed at a focal position of the image pickup lens system.
　本発明によれば、広角で、明るく、かつ、小型の撮像レンズ系を提供することができる。 According to the present invention, a wide-angle, bright and small imaging lens system can be provided.
実施の形態１に係る撮像装置の断面図である。2 is a cross-sectional view of the imaging apparatus according to Embodiment 1. FIG. 実施例１に係る撮像レンズ系の断面図である。1 is a cross-sectional view of an imaging lens system according to Example 1. FIG. 実施例１に係る撮像レンズ系の収差図である。FIG. 4 is an aberration diagram of the imaging lens system according to Example 1. 実施例１に係る撮像レンズ系の収差図である。FIG. 4 is an aberration diagram of the imaging lens system according to Example 1. 実施例１に係る撮像レンズ系の収差図である。FIG. 4 is an aberration diagram of the imaging lens system according to Example 1. 実施例２に係る撮像レンズ系の断面図である。6 is a cross-sectional view of an imaging lens system according to Example 2. FIG. 実施例２に係る撮像レンズ系の収差図である。6 is an aberration diagram of the imaging lens system according to Example 2. FIG. 実施例２に係る撮像レンズ系の収差図である。6 is an aberration diagram of the imaging lens system according to Example 2. FIG. 実施例２に係る撮像レンズ系の収差図である。6 is an aberration diagram of the imaging lens system according to Example 2. FIG. 実施例３に係る撮像レンズ系の断面図である。6 is a cross-sectional view of an imaging lens system according to Example 3. FIG. 実施例３に係る撮像レンズ系の収差図である。FIG. 6 is an aberration diagram of the imaging lens system according to Example 3. 実施例３に係る撮像レンズ系の収差図である。FIG. 6 is an aberration diagram of the imaging lens system according to Example 3. 実施例３に係る撮像レンズ系の収差図である。FIG. 6 is an aberration diagram of the imaging lens system according to Example 3. 実施例４に係る撮像レンズ系の断面図である。6 is a cross-sectional view of an imaging lens system according to Example 4. FIG. 実施例４に係る撮像レンズ系の収差図である。FIG. 10 is an aberration diagram of the imaging lens system according to Example 4. 実施例４に係る撮像レンズ系の収差図である。FIG. 10 is an aberration diagram of the imaging lens system according to Example 4. 実施例４に係る撮像レンズ系の収差図である。FIG. 10 is an aberration diagram of the imaging lens system according to Example 4. 実施例５に係る撮像レンズ系の断面図である。6 is a cross-sectional view of an imaging lens system according to Example 5. FIG. 実施例５に係る撮像レンズ系の収差図である。FIG. 10 is an aberration diagram of the imaging lens system according to Example 5. 実施例５に係る撮像レンズ系の収差図である。FIG. 10 is an aberration diagram of the imaging lens system according to Example 5. 実施例５に係る撮像レンズ系の収差図である。FIG. 10 is an aberration diagram of the imaging lens system according to Example 5. 実施例６に係る撮像レンズ系の断面図である。10 is a cross-sectional view of an imaging lens system according to Example 6. FIG. 実施例６に係る撮像レンズ系の収差図である。10 is an aberration diagram of the imaging lens system according to Example 6. FIG. 実施例６に係る撮像レンズ系の収差図である。10 is an aberration diagram of the imaging lens system according to Example 6. FIG. 実施例６に係る撮像レンズ系の収差図である。10 is an aberration diagram of the imaging lens system according to Example 6. FIG.
　以下、本発明の実施の形態に係る撮像レンズ系１０１の実施例について説明する。 Hereinafter, examples of the imaging lens system 101 according to the embodiment of the present invention will be described.
　(実施例１)
　図２は、実施例１の撮像レンズ系１０１の構成を示す図である。
　図２に示すように、実施例１の撮像レンズ系１０１は、物体側から像側に向かって順に、負のパワーを有する第１レンズ群Ｇ１と、正のパワーを有する第２レンズ群Ｇ２と、絞りＳＴＯＰと、正のパワーを有する第３レンズ群Ｇ３と、から構成される。第１レンズ群Ｇ１は、レンズＬ１１から構成される。第２レンズ群Ｇ２は、レンズＬ２１から構成される。第３レンズ群Ｇ３は、レンズＬ３１から構成される。撮像レンズ系１０１の結像面はＩＭＧで示されている。実施例１の撮像レンズ系１０１では、レンズＬ１１、レンズＬ２１、及び、レンズＬ３１はプラスチックレンズである。 (Example 1)
FIG. 2 is a diagram illustrating a configuration of the imaging lens system 101 according to the first embodiment.
As illustrated in FIG. 2, the imaging lens system 101 according to the first exemplary embodiment includes, in order from the object side to the image side, a first lens group G1 having a negative power and a second lens group G2 having a positive power. And a stop STOP and a third lens group G3 having a positive power. The first lens group G1 includes a lens L11. The second lens group G2 includes a lens L21. The third lens group G3 includes a lens L31. The imaging plane of the imaging lens system 101 is indicated by IMG. In the imaging lens system 101 of Example 1, the lens L11, the lens L21, and the lens L31 are plastic lenses.
　レンズＬ１１は、負のパワーを有する非球面レンズである。レンズＬ１１の物体側レンズ面Ｓ１は負の曲率を有する球面であり、像側レンズ面Ｓ２は正の曲率を有する非球面である。物体側レンズ面Ｓ１は物体側に凹面を向けており、像側レンズ面Ｓ２は物体側に突出する凸形状の曲面部分を有している。 The lens L11 is an aspheric lens having negative power. The object side lens surface S1 of the lens L11 is a spherical surface having a negative curvature, and the image side lens surface S2 is an aspherical surface having a positive curvature. The object side lens surface S1 has a concave surface facing the object side, and the image side lens surface S2 has a convex curved surface portion protruding toward the object side.
　レンズＬ２１は、正のパワーを有する非球面レンズである。物体側レンズ面Ｓ３は正の曲率を有する非球面であり、像側レンズ面Ｓ４は正の曲率を有する非球面である。物体側レンズ面Ｓ３は物体側に突出する凸形状の曲面部分を有しており、像側レンズ面Ｓ４は物体側に突出する凸形状の曲面部分を有している。 The lens L21 is an aspheric lens having positive power. The object side lens surface S3 is an aspherical surface having a positive curvature, and the image side lens surface S4 is an aspherical surface having a positive curvature. The object side lens surface S3 has a convex curved surface portion protruding toward the object side, and the image side lens surface S4 has a convex curved surface portion protruding toward the object side.
　レンズＬ３１は、正のパワーを有する非球面レンズである。物体側レンズ面Ｓ６は負の曲率を有する非球面であり、像側レンズ面Ｓ７は負の曲率を有する非球面である。物体側レンズ面Ｓ６は像側に突出する凸形状の曲面部分を有しており、像側レンズ面Ｓ７は像側に突出する凸形状の曲面部分を有している。 The lens L31 is an aspheric lens having positive power. The object side lens surface S6 is an aspherical surface having a negative curvature, and the image side lens surface S7 is an aspherical surface having a negative curvature. The object side lens surface S6 has a convex curved surface portion protruding toward the image side, and the image side lens surface S7 has a convex curved surface portion protruding toward the image side.
　表１に、撮像レンズ系１０１の各レンズ面のレンズデータを示す。レンズデータとしては、各面の曲率半径、面間隔、屈折率、及びアッベ数を載せている。「＊印」がついた面は、非球面であることを示している。 Table 1 shows lens data of each lens surface of the imaging lens system 101. The lens data includes the radius of curvature, surface spacing, refractive index, and Abbe number of each surface. A surface marked with “*” indicates an aspherical surface.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　レンズ面に採用する非球面形状は、ｚをサグ量、ｃを曲率半径の逆数、ｋを円錐係数、ｒを光軸からの光線高さとして、１次、２次、３次、４次、５次、６次、７次、８次の非球面係数をそれぞれβ１、β２、β３、β４、β５、β６、β７、β８、としたときに、次式により表わされる。 The aspherical shape adopted for the lens surface is a first-order, second-order, third-order, fourth-order, where z is the sag amount, c is the reciprocal of the radius of curvature, k is the conic coefficient, and r is the height of the light beam from the optical axis. When the fifth-order, sixth-order, seventh-order, and eighth-order aspherical coefficients are β1, β2, β3, β4, β5, β6, β7, and β8, respectively, they are expressed by the following equations.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　表２に、実施例１の撮像レンズ系１０１において、非球面とされたレンズ面の非球面形状を規定するための非球面係数を示す。表２において、例えば「－６．５２２５２８Ｅ－０３」は、「－６．５２２５２８×１０－３」を意味する。 Table 2 shows the aspheric coefficients for defining the aspherical shape of the aspherical lens surface in the imaging lens system 101 of Example 1. In Table 2, for example, “−6.522528E-03” means “−6.522528 × 10 −3 ”.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　図３Ａ～図３Ｃは、実施例１の撮像レンズ系１０１の縦収差図、像面湾曲図、歪曲収差図である。図３Ａ～図３Ｃに示すように、実施例１の撮像レンズ系１０１では、半画角ωが８０°、Ｆナンバが２．０である。図３Ａの縦収差図では、横軸は光線が光軸Ｚと交わる位置を示し、縦軸は瞳径での高さを示す。図３Ｂの像面湾曲図では、横軸は光軸Ｚ方向の距離を示し、縦軸は像高（画角）を示す。図３Ｂにおいて、Ｓａｇはサジタル面における像面湾曲を示し、Ｔａｎはタンジェンシャル面における像面湾曲を示す。図３Ｃの歪曲収差図では、横軸は像の歪み量（％）を示し、縦軸は像高（画角）を示す。図３Ａ～図３Ｃでは、波長５４６ｎｍの光線によるシミュレーション結果を示してある。 3A to 3C are a longitudinal aberration diagram, a field curvature diagram, and a distortion diagram of the imaging lens system 101 according to the first embodiment. As shown in FIGS. 3A to 3C, in the imaging lens system 101 of Example 1, the half angle of view ω is 80 ° and the F number is 2.0. In the longitudinal aberration diagram of FIG. 3A, the horizontal axis indicates the position where the light beam intersects the optical axis Z, and the vertical axis indicates the height at the pupil diameter. In the field curvature diagram of FIG. 3B, the horizontal axis indicates the distance in the optical axis Z direction, and the vertical axis indicates the image height (field angle). In FIG. 3B, Sag indicates the field curvature in the sagittal plane, and Tan indicates the field curvature in the tangential plane. In the distortion diagram of FIG. 3C, the horizontal axis represents the amount of distortion (%) of the image, and the vertical axis represents the image height (field angle). FIG. 3A to FIG. 3C show simulation results using light rays having a wavelength of 546 nm.
　表３に、実施例１の撮像レンズ系１０１の特性値を計算した結果を示す。撮像レンズ系１０１において、ＦナンバをＦＮｏ、第１レンズＬ１の物体側レンズ面Ｓ１から撮像レンズ系１０１の結像面ＩＭＧまでの距離（光学全長）をＴＬ、レンズ系全体の焦点距離をｆ、第１レンズ群Ｇ１の焦点距離をｆ１、第２レンズ群Ｇ２の焦点距離をｆ２、第３レンズ群Ｇ３の焦点距離をｆ３、第１レンズ群Ｇ１と第２レンズ群Ｇ２との合成焦点距離をｆ１２、第２レンズ群Ｇ２と第３レンズ群Ｇ３との合成焦点距離をｆ２３、レンズＬ３１の像側レンズ面Ｓ７の焦点距離をｆＬ３１Ｒ２、としたときのこれらの特性値は、表３に示す通りである。各種の焦点距離は、５４６ｎｍの波長の光線を用いて計算した。 Table 3 shows the result of calculating the characteristic value of the imaging lens system 101 of Example 1. In the imaging lens system 101, the F number is FNo, the distance (optical total length) from the object-side lens surface S1 of the first lens L1 to the imaging surface IMG of the imaging lens system 101 is TL, the focal length of the entire lens system is f, The focal length of the first lens group G1 is f 1 , the focal length of the second lens group G2 is f 2 , the focal length of the third lens group G3 is f 3 , and the first lens group G1 and the second lens group G2 are combined. When the focal length is f 12 , the combined focal length of the second lens group G2 and the third lens group G3 is f 23 , and the focal length of the image side lens surface S7 of the lens L31 is f L31R2 , these characteristic values are As shown in Table 3. Various focal lengths were calculated using light rays with a wavelength of 546 nm.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　(実施例２)
　図４は、実施例２の撮像レンズ系１０１の構成を示す図である。
　図４に示すように、実施例２の撮像レンズ系１０１は、物体側から像側に向かって順に、負のパワーを有する第１レンズ群Ｇ１と、正のパワーを有する第２レンズ群Ｇ２と、絞りと、正のパワーを有する第３レンズ群Ｇ３と、から構成される。第１レンズ群Ｇ１は、レンズＬ１１から構成される。第２レンズ群Ｇ２は、レンズＬ２１から構成される。第３レンズ群Ｇ３は、レンズＬ３１から構成される。実施例１の撮像レンズ系１０１では、レンズＬ１１はガラスレンズで、レンズＬ２１及びレンズＬ３１はプラスチックレンズである。 (Example 2)
FIG. 4 is a diagram illustrating a configuration of the imaging lens system 101 according to the second embodiment.
As illustrated in FIG. 4, the imaging lens system 101 according to the second embodiment includes, in order from the object side to the image side, a first lens group G1 having a negative power and a second lens group G2 having a positive power. , And a third lens group G3 having a positive power. The first lens group G1 includes a lens L11. The second lens group G2 includes a lens L21. The third lens group G3 includes a lens L31. In the imaging lens system 101 of Example 1, the lens L11 is a glass lens, and the lenses L21 and L31 are plastic lenses.
　レンズＬ１１は、負のパワーを有する球面メニスカスレンズである。レンズＬ１１の物体側レンズ面Ｓ１は正の曲率を有する球面であり、像側レンズ面Ｓ２は正の曲率を有する球面である。物体側レンズ面Ｓ１及び像側レンズ面Ｓ２は像側に凹面を向けている。 The lens L11 is a spherical meniscus lens having negative power. The object side lens surface S1 of the lens L11 is a spherical surface having a positive curvature, and the image side lens surface S2 is a spherical surface having a positive curvature. The object side lens surface S1 and the image side lens surface S2 are concave on the image side.
　レンズＬ２１は、正のパワーを有する非球面レンズである。物体側レンズ面Ｓ３は正の曲率を有する非球面であり、像側レンズ面Ｓ４は正の曲率を有する非球面である。物体側レンズ面Ｓ３は物体側に突出する凸形状の曲面部分を有しており、像側レンズ面Ｓ４は物体側に突出する凸形状の曲面部分を有している。 The lens L21 is an aspheric lens having positive power. The object side lens surface S3 is an aspherical surface having a positive curvature, and the image side lens surface S4 is an aspherical surface having a positive curvature. The object side lens surface S3 has a convex curved surface portion protruding toward the object side, and the image side lens surface S4 has a convex curved surface portion protruding toward the object side.
　レンズＬ３１は、正のパワーを有する非球面レンズである。物体側レンズ面Ｓ６は負の曲率を有する非球面であり、像側レンズ面Ｓ７は負の曲率を有する非球面である。物体側レンズ面Ｓ６は像側に突出する凸形状の曲面部分を有しており、像側レンズ面Ｓ７は像側に突出する凸形状の曲面部分を有している。 The lens L31 is an aspheric lens having positive power. The object side lens surface S6 is an aspherical surface having a negative curvature, and the image side lens surface S7 is an aspherical surface having a negative curvature. The object side lens surface S6 has a convex curved surface portion protruding toward the image side, and the image side lens surface S7 has a convex curved surface portion protruding toward the image side.
　表４に、撮像レンズ系１０１の各レンズ面のレンズデータを示す。「＊印」がついた面は、非球面であることを示している。 Table 4 shows lens data of each lens surface of the imaging lens system 101. A surface marked with “*” indicates an aspherical surface.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　表５に、実施例２の撮像レンズ系１０１において、非球面とされたレンズ面の非球面形状を規定するための非球面係数を示す。 Table 5 shows the aspherical coefficients for defining the aspherical shape of the aspherical lens surface in the imaging lens system 101 of Example 2.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　図５Ａ～図５Ｃは、実施例２の撮像レンズ系１０１の縦収差図、像面湾曲図、歪曲収差図である。図５Ａ～図５Ｃに示すように、実施例２の撮像レンズ系１０１では、半画角ωが８０°、Ｆナンバが２．０である。図５Ａの縦収差図では、横軸は光線が光軸Ｚと交わる位置を示し、縦軸は瞳径での高さを示す。図５Ｂの像面湾曲図では、横軸は光軸Ｚ方向の距離を示し、縦軸は像高（画角）を示す。図５Ｂにおいて、Ｓａｇはサジタル面における像面湾曲を示し、Ｔａｎはタンジェンシャル面における像面湾曲を示す。図５Ｃの歪曲収差図では、横軸は像の歪み量（％）を示し、縦軸は像高（画角）を示す。図５Ａ～図５Ｃでは、波長５４６ｎｍの光線によるシミュレーション結果を示してある。 FIGS. 5A to 5C are a longitudinal aberration diagram, a field curvature diagram, and a distortion diagram of the imaging lens system 101 of the second embodiment. As shown in FIGS. 5A to 5C, in the imaging lens system 101 of Example 2, the half angle of view ω is 80 ° and the F number is 2.0. In the longitudinal aberration diagram of FIG. 5A, the horizontal axis indicates the position where the light beam intersects the optical axis Z, and the vertical axis indicates the height at the pupil diameter. In the field curvature diagram of FIG. 5B, the horizontal axis indicates the distance in the optical axis Z direction, and the vertical axis indicates the image height (field angle). In FIG. 5B, Sag indicates the field curvature in the sagittal plane, and Tan indicates the field curvature in the tangential plane. In the distortion diagram of FIG. 5C, the horizontal axis represents the amount of distortion (%) of the image, and the vertical axis represents the image height (field angle). FIG. 5A to FIG. 5C show simulation results using light rays having a wavelength of 546 nm.
　表６に、実施例２の撮像レンズ系１０１の特性値を計算した結果を示す。表６には、表３と同様の特性値について計算した結果を示す。 Table 6 shows the results of calculating the characteristic values of the imaging lens system 101 of Example 2. Table 6 shows the results calculated for the same characteristic values as in Table 3.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　(実施例３)
　図６は、実施例３の撮像レンズ系１０１の構成を示す図である。
　実施例３の撮像レンズ系１０１は、物体側から像側に向かって順に、負のパワーを有する第１レンズ群Ｇ１と、正のパワーを有する第２レンズ群Ｇ２と、絞りと、正のパワーを有する第３レンズ群Ｇ３と、から構成される。第１レンズ群Ｇ１は、レンズＬ１１及びレンズＬ１２から構成される。第２レンズ群Ｇ２は、レンズＬ２１から構成される。第３レンズ群Ｇ３は、レンズＬ３１から構成される。実施例３の撮像レンズ系１０１では、レンズＬ１１はガラスレンズであり、レンズＬ１２、レンズＬ２１、及びレンズＬ３１はプラスチックレンズである。 Example 3
FIG. 6 is a diagram illustrating a configuration of the imaging lens system 101 according to the third embodiment.
The imaging lens system 101 according to the third exemplary embodiment includes, in order from the object side to the image side, a first lens group G1 having a negative power, a second lens group G2 having a positive power, a diaphragm, and a positive power. And a third lens group G3. The first lens group G1 includes a lens L11 and a lens L12. The second lens group G2 includes a lens L21. The third lens group G3 includes a lens L31. In the imaging lens system 101 of Example 3, the lens L11 is a glass lens, and the lens L12, the lens L21, and the lens L31 are plastic lenses.
　レンズＬ１１は、負のパワーを有する球面メニスカスレンズである。レンズＬ１１の物体側レンズ面Ｓ１は正の曲率を有する球面であり、像側レンズ面Ｓ２は正の曲率を有する球面である。物体側レンズ面Ｓ１及び像側レンズ面Ｓ２は像側に凹面を向けている。 The lens L11 is a spherical meniscus lens having negative power. The object side lens surface S1 of the lens L11 is a spherical surface having a positive curvature, and the image side lens surface S2 is a spherical surface having a positive curvature. The object side lens surface S1 and the image side lens surface S2 are concave on the image side.
　レンズＬ１２は、負のパワーを有する非球面レンズである。レンズＬ１２の物体側レンズ面Ｓ３は負の曲率を有する非球面であり、像側レンズ面Ｓ４は正の曲率を有する非球面である。物体側レンズ面Ｓ３は像側に突出する凸形状の曲面部分を有しており、像側レンズ面Ｓ４は物体側に突出する凸形状の曲面部分を有している。 Lens L12 is an aspherical lens having negative power. The object side lens surface S3 of the lens L12 is an aspheric surface having a negative curvature, and the image side lens surface S4 is an aspheric surface having a positive curvature. The object side lens surface S3 has a convex curved surface portion protruding toward the image side, and the image side lens surface S4 has a convex curved surface portion protruding toward the object side.
　レンズＬ２１は、正のパワーを有する非球面レンズである。物体側レンズ面Ｓ５は正の曲率を有する非球面であり、像側レンズ面Ｓ６は正の曲率を有する非球面である。物体側レンズ面Ｓ５は物体側に突出する凸形状の曲面部分を有しており、像側レンズ面Ｓ６は物体側に突出する凸形状の曲面部分を有している。 The lens L21 is an aspheric lens having positive power. The object side lens surface S5 is an aspherical surface having a positive curvature, and the image side lens surface S6 is an aspherical surface having a positive curvature. The object side lens surface S5 has a convex curved surface portion protruding toward the object side, and the image side lens surface S6 has a convex curved surface portion protruding toward the object side.
　レンズＬ３１は、正のパワーを有する非球面レンズである。物体側レンズ面Ｓ８は正の曲率を有する非球面であり、像側レンズ面Ｓ９は負の曲率を有する非球面である。物体側レンズ面Ｓ８は物体側に突出する凸形状の曲面部分を有しており、像側レンズ面Ｓ９は像側に突出する凸形状の曲面部分を有している。 The lens L31 is an aspheric lens having positive power. The object side lens surface S8 is an aspherical surface having a positive curvature, and the image side lens surface S9 is an aspherical surface having a negative curvature. The object side lens surface S8 has a convex curved surface portion protruding toward the object side, and the image side lens surface S9 has a convex curved surface portion protruding toward the image side.
　表７に、撮像レンズ系１０１の各レンズ面のレンズデータを示す。「＊印」がついた面は、非球面であることを示している。 Table 7 shows lens data of each lens surface of the imaging lens system 101. A surface marked with “*” indicates an aspherical surface.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　レンズＬ２１及びレンズＬ３１のレンズ面に採用される非球面形状は、実施例１で説明した数式で表される。レンズＬ１２のレンズ面に採用される非球面形状は、ｚをサグ量、ｃを曲率半径の逆数、ｋを円錐係数、ｒを光軸からの光線高さとして、４次、６次、８次、１０次、１２次、１４次、１６次の非球面係数をそれぞれα４、α６、α８、α１０、α１２、α１４、としたときに、次式により表わされる。 The aspherical shape adopted for the lens surfaces of the lens L21 and the lens L31 is expressed by the mathematical formula described in the first embodiment. The aspherical shape adopted for the lens surface of the lens L12 is 4th order, 6th order, 8th order, where z is the sag amount, c is the reciprocal of the radius of curvature, k is the cone coefficient, and r is the height of the light beam from the optical axis. When the 10th-order, 12th-order, 14th-order, and 16th-order aspherical coefficients are α4, α6, α8, α10, α12, and α14, respectively, they are expressed by the following equations.
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　表８に、実施例３の撮像レンズ系１０１において、非球面とされたレンズ面の非球面形状を規定するための非球面係数を示す。 Table 8 shows aspherical coefficients for defining the aspherical shape of the aspherical lens surface in the imaging lens system 101 of Example 3.
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
　図７Ａ～図７Ｃは、実施例３の撮像レンズ系１０１の縦収差図、像面湾曲図、歪曲収差図である。図７Ａ～図７Ｃに示すように、実施例３の撮像レンズ系１０１では、半画角ωが８９°、Ｆナンバが２．０である。図７Ａの縦収差図では、横軸は光線が光軸Ｚと交わる位置を示し、縦軸は瞳径での高さを示す。図７Ｂの像面湾曲図では、横軸は光軸Ｚ方向の距離を示し、縦軸は像高（画角）を示す。図７Ｂにおいて、Ｓａｇはサジタル面における像面湾曲を示し、Ｔａｎはタンジェンシャル面における像面湾曲を示す。図７Ｃの歪曲収差図では、横軸は像の歪み量（％）を示し、縦軸は像高（画角）を示す。図７Ａ～図７Ｃでは、波長５４６ｎｍの光線によるシミュレーション結果を示してある。 7A to 7C are a longitudinal aberration diagram, a field curvature diagram, and a distortion diagram of the imaging lens system 101 of Example 3. FIG. As shown in FIGS. 7A to 7C, in the imaging lens system 101 of Example 3, the half angle of view ω is 89 ° and the F number is 2.0. In the longitudinal aberration diagram of FIG. 7A, the horizontal axis indicates the position where the light beam intersects the optical axis Z, and the vertical axis indicates the height at the pupil diameter. In the field curvature diagram of FIG. 7B, the horizontal axis indicates the distance in the optical axis Z direction, and the vertical axis indicates the image height (field angle). In FIG. 7B, Sag indicates the field curvature in the sagittal plane, and Tan indicates the field curvature in the tangential plane. In the distortion diagram of FIG. 7C, the horizontal axis represents the amount of distortion (%) of the image, and the vertical axis represents the image height (field angle). 7A to 7C show simulation results using light rays having a wavelength of 546 nm.
　表９に、実施例３の撮像レンズ系１０１の特性値を計算した結果を示す。撮像レンズ系１０１において、ＦナンバをＦＮｏ、第１レンズＬ１１の物体側レンズ面Ｓ１から撮像レンズ系１０１の結像面ＩＭＧまでの距離（光学全長）をＴＬ、レンズ系全体の焦点距離をｆ、第１レンズ群Ｇ１の焦点距離をｆ１、第２レンズ群Ｇ２の焦点距離をｆ２、第３レンズ群Ｇ３の焦点距離をｆ３、レンズＬ１１の焦点距離をｆＬ１１、レンズＬ１２の焦点距離をｆＬ１２、第１レンズ群Ｇ１と第２レンズ群Ｇ２との合成焦点距離をｆ１２、第２レンズ群Ｇ２と第３レンズ群Ｇ３との合成焦点距離をｆ２３、レンズＬ１２とレンズＬ２１との合成焦点距離をｆＬ１２Ｌ２１、レンズＬ１１とレンズＬ１２とレンズＬ２１との合成焦点距離をｆＬ１１Ｌ２１、レンズＬ１２とレンズＬ２１とレンズＬ３１との合成焦点距離をｆＬ１２Ｌ３１、レンズＬ３１の像側レンズ面Ｓ７の焦点距離をｆＬ３１Ｒ２、としたときのこれらの特性値は、表９に示す通りである。各種の焦点距離は、５４６ｎｍの波長の光線を用いて計算した。 Table 9 shows the results of calculating the characteristic values of the imaging lens system 101 of Example 3. In the imaging lens system 101, the F number is FNo, the distance from the object-side lens surface S1 of the first lens L11 to the imaging surface IMG of the imaging lens system 101 is TL, the focal length of the entire lens system is f, focal length f 1 of the first lens group G1, the focal length f 2 of the second lens group G2, the focal length f 3 of the third lens group G3, the focal distance f L11 of the lens L11, the focal length of the lens L12 F L12 , the combined focal length of the first lens group G1 and the second lens group G2 is f 12 , the combined focal length of the second lens group G2 and the third lens group G3 is f 23 , and the lens L12 and the lens L21 combined focal distance of the composite focal distance f L12L21, a composite focal length of the lens L11 and the lens L12 and the lens L21 and f L11L21, lens L12 and a lens L21 and lens L31 The f L12L31, these characteristic values when the focal length of the image side lens surface S7 in the lens L31 and f L31R2, and are as shown in Table 9. Various focal lengths were calculated using light rays with a wavelength of 546 nm.
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
　(実施例４)
　図８は、実施例４の撮像レンズ系１０１の構成を示す図である。
　実施例４の撮像レンズ系１０１は、物体側から像側に向かって順に、負のパワーを有する第１レンズ群Ｇ１と、正のパワーを有する第２レンズ群Ｇ２と、絞りと、正のパワーを有する第３レンズ群Ｇ３と、から構成される。第１レンズ群Ｇ１は、レンズＬ１１及びレンズＬ１２から構成される。第２レンズ群Ｇ２は、レンズＬ２１から構成される。第３レンズ群Ｇ３は、レンズＬ３１から構成される。実施例４の撮像レンズ系１０１では、レンズＬ１１はガラスレンズであり、レンズＬ１２、レンズＬ２１、及びレンズＬ３１はプラスチックレンズである。 Example 4
FIG. 8 is a diagram illustrating a configuration of the imaging lens system 101 according to the fourth embodiment.
The imaging lens system 101 according to the fourth exemplary embodiment includes, in order from the object side to the image side, a first lens group G1 having a negative power, a second lens group G2 having a positive power, a diaphragm, and a positive power. And a third lens group G3. The first lens group G1 includes a lens L11 and a lens L12. The second lens group G2 includes a lens L21. The third lens group G3 includes a lens L31. In the imaging lens system 101 of Example 4, the lens L11 is a glass lens, and the lens L12, the lens L21, and the lens L31 are plastic lenses.
　レンズＬ１１は、負のパワーを有する球面メニスカスレンズである。レンズＬ１１の物体側レンズ面Ｓ１は正の曲率を有する球面であり、像側レンズ面Ｓ２は正の曲率を有する球面である。物体側レンズ面Ｓ１及び像側レンズ面Ｓ２は像側に凹面を向けている。 The lens L11 is a spherical meniscus lens having negative power. The object side lens surface S1 of the lens L11 is a spherical surface having a positive curvature, and the image side lens surface S2 is a spherical surface having a positive curvature. The object side lens surface S1 and the image side lens surface S2 are concave on the image side.
　レンズＬ１２は、負のパワーを有する非球面レンズである。レンズＬ１２の物体側レンズ面Ｓ３は負の曲率を有する非球面であり、像側レンズ面Ｓ４は正の曲率を有する非球面である。物体側レンズ面Ｓ３は像側に突出する凸形状の曲面部分を有しており、像側レンズ面Ｓ４は物体側に突出する凸形状の曲面部分を有している。 Lens L12 is an aspherical lens having negative power. The object side lens surface S3 of the lens L12 is an aspheric surface having a negative curvature, and the image side lens surface S4 is an aspheric surface having a positive curvature. The object side lens surface S3 has a convex curved surface portion protruding toward the image side, and the image side lens surface S4 has a convex curved surface portion protruding toward the object side.
　レンズＬ２１は、正のパワーを有する非球面レンズである。物体側レンズ面Ｓ５は正の曲率を有する非球面であり、像側レンズ面Ｓ６は正の曲率を有する非球面である。物体側レンズ面Ｓ５は物体側に突出する凸形状の曲面部分を有しており、像側レンズ面Ｓ６は物体側に突出する凸形状の曲面部分を有している。 The lens L21 is an aspheric lens having positive power. The object side lens surface S5 is an aspherical surface having a positive curvature, and the image side lens surface S6 is an aspherical surface having a positive curvature. The object side lens surface S5 has a convex curved surface portion protruding toward the object side, and the image side lens surface S6 has a convex curved surface portion protruding toward the object side.
　レンズＬ３１は、正のパワーを有する非球面レンズである。物体側レンズ面Ｓ８は正の曲率を有する非球面であり、像側レンズ面Ｓ９は負の曲率を有する非球面である。物体側レンズ面Ｓ８は物体側に突出する凸形状の曲面部分を有しており、像側レンズ面Ｓ９は像側に突出する凸形状の曲面部分を有している。 The lens L31 is an aspheric lens having positive power. The object side lens surface S8 is an aspherical surface having a positive curvature, and the image side lens surface S9 is an aspherical surface having a negative curvature. The object side lens surface S8 has a convex curved surface portion protruding toward the object side, and the image side lens surface S9 has a convex curved surface portion protruding toward the image side.
　表１０に、撮像レンズ系１０１の各レンズ面のレンズデータを示す。「＊印」がついた面は、非球面であることを示している。 Table 10 shows lens data of each lens surface of the imaging lens system 101. A surface marked with “*” indicates an aspherical surface.
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
　表１１に、実施例４の撮像レンズ系１０１において、非球面とされたレンズ面の非球面形状を規定するための非球面係数を示す。 Table 11 shows the aspheric coefficients for defining the aspheric shape of the aspheric lens surface in the imaging lens system 101 of Example 4.
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000011
　図９Ａ～図９Ｃは、実施例４の撮像レンズ系１０１の縦収差図、像面湾曲図、歪曲収差図である。図９Ａ～図９Ｃに示すように、実施例４の撮像レンズ系１０１では、半画角ωが８９°、Ｆナンバが２．０である。図９Ａの縦収差図では、横軸は光線が光軸Ｚと交わる位置を示し、縦軸は瞳径での高さを示す。図９Ｂの像面湾曲図では、横軸は光軸Ｚ方向の距離を示し、縦軸は像高（画角）を示す。図９Ｂにおいて、Ｓａｇはサジタル面における像面湾曲を示し、Ｔａｎはタンジェンシャル面における像面湾曲を示す。図９Ｃの歪曲収差図では、横軸は像の歪み量（％）を示し、縦軸は像高（画角）を示す。図９Ａ～図９Ｃでは、波長５４６ｎｍの光線によるシミュレーション結果を示してある。 FIGS. 9A to 9C are a longitudinal aberration diagram, a field curvature diagram, and a distortion diagram of the imaging lens system 101 of Example 4. FIG. As shown in FIGS. 9A to 9C, in the imaging lens system 101 of Example 4, the half angle of view ω is 89 ° and the F number is 2.0. In the longitudinal aberration diagram of FIG. 9A, the horizontal axis indicates the position where the light beam intersects the optical axis Z, and the vertical axis indicates the height at the pupil diameter. In the field curvature diagram of FIG. 9B, the horizontal axis indicates the distance in the optical axis Z direction, and the vertical axis indicates the image height (field angle). In FIG. 9B, Sag indicates the field curvature in the sagittal plane, and Tan indicates the field curvature in the tangential plane. In the distortion diagram of FIG. 9C, the horizontal axis indicates the amount of image distortion (%), and the vertical axis indicates the image height (angle of view). FIG. 9A to FIG. 9C show simulation results using light rays having a wavelength of 546 nm.
　表１２に、実施例４の撮像レンズ系１０１の特性値を計算した結果を示す。表１２には、表９と同様の特性値について計算した結果を示す。 Table 12 shows the result of calculating the characteristic values of the imaging lens system 101 of Example 4. Table 12 shows the calculation results for the same characteristic values as in Table 9.
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000012
　(実施例５)
　図１０は、実施例５の撮像レンズ系１０１の構成を示す図である。
　実施例５の撮像レンズ系１０１は、物体側から像側に向かって順に、負のパワーを有する第１レンズ群Ｇ１と、正のパワーを有する第２レンズ群Ｇ２と、絞りと、正のパワーを有する第３レンズ群Ｇ３と、から構成される。第１レンズ群Ｇ１は、レンズＬ１１及びレンズＬ１２から構成される。第２レンズ群Ｇ２は、レンズＬ２１から構成される。第３レンズ群Ｇ３は、レンズＬ３１から構成される。実施例５の撮像レンズ系１０１では、レンズＬ１１はガラスレンズであり、レンズＬ１２、レンズＬ２１、及びレンズＬ３１はプラスチックレンズである。 (Example 5)
FIG. 10 is a diagram illustrating a configuration of the imaging lens system 101 according to the fifth embodiment.
The imaging lens system 101 according to the fifth exemplary embodiment includes, in order from the object side to the image side, a first lens group G1 having a negative power, a second lens group G2 having a positive power, a diaphragm, and a positive power. And a third lens group G3. The first lens group G1 includes a lens L11 and a lens L12. The second lens group G2 includes a lens L21. The third lens group G3 includes a lens L31. In the imaging lens system 101 of Example 5, the lens L11 is a glass lens, and the lens L12, the lens L21, and the lens L31 are plastic lenses.
　レンズＬ１１は、負のパワーを有する球面メニスカスレンズである。レンズＬ１１の物体側レンズ面Ｓ１は正の曲率を有する球面であり、像側レンズ面Ｓ２は正の曲率を有する球面である。物体側レンズ面Ｓ１及び像側レンズ面Ｓ２は像側に凹面を向けている。 The lens L11 is a spherical meniscus lens having negative power. The object side lens surface S1 of the lens L11 is a spherical surface having a positive curvature, and the image side lens surface S2 is a spherical surface having a positive curvature. The object side lens surface S1 and the image side lens surface S2 are concave on the image side.
　レンズＬ１２は、負のパワーを有する非球面レンズである。レンズＬ１２の物体側レンズ面Ｓ３は負の曲率を有する非球面であり、像側レンズ面Ｓ４は正の曲率を有する非球面である。物体側レンズ面Ｓ３は像側に突出する凸形状の曲面部分を有しており、像側レンズ面Ｓ４は物体側に突出する凸形状の曲面部分を有している。 Lens L12 is an aspherical lens having negative power. The object side lens surface S3 of the lens L12 is an aspheric surface having a negative curvature, and the image side lens surface S4 is an aspheric surface having a positive curvature. The object side lens surface S3 has a convex curved surface portion protruding toward the image side, and the image side lens surface S4 has a convex curved surface portion protruding toward the object side.
　レンズＬ２１は、正のパワーを有する非球面レンズである。物体側レンズ面Ｓ５は正の曲率を有する非球面であり、像側レンズ面Ｓ６は正の曲率を有する非球面である。物体側レンズ面Ｓ５は物体側に突出する凸形状の曲面部分を有しており、像側レンズ面Ｓ６は物体側に突出する凸形状の曲面部分を有している。 The lens L21 is an aspheric lens having positive power. The object side lens surface S5 is an aspherical surface having a positive curvature, and the image side lens surface S6 is an aspherical surface having a positive curvature. The object side lens surface S5 has a convex curved surface portion protruding toward the object side, and the image side lens surface S6 has a convex curved surface portion protruding toward the object side.
　レンズＬ３１は、正のパワーを有する非球面レンズである。物体側レンズ面Ｓ８は負の曲率を有する非球面であり、像側レンズ面Ｓ９は負の曲率を有する非球面である。物体側レンズ面Ｓ８は像側に突出する凸形状の曲面部分を有しており、像側レンズ面Ｓ９は像側に突出する凸形状の曲面部分を有している。 The lens L31 is an aspheric lens having positive power. The object side lens surface S8 is an aspherical surface having a negative curvature, and the image side lens surface S9 is an aspherical surface having a negative curvature. The object side lens surface S8 has a convex curved surface portion protruding toward the image side, and the image side lens surface S9 has a convex curved surface portion protruding toward the image side.
　表１３に、撮像レンズ系１０１の各レンズ面のレンズデータを示す。「＊印」がついた面は、非球面であることを示している。 Table 13 shows lens data of each lens surface of the imaging lens system 101. A surface marked with “*” indicates an aspherical surface.
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000013
　表１４に、実施例５の撮像レンズ系１０１において、非球面とされたレンズ面の非球面形状を規定するための非球面係数を示す。 Table 14 shows the aspherical coefficients for defining the aspherical shape of the aspherical lens surface in the imaging lens system 101 of Example 5.
Figure JPOXMLDOC01-appb-T000014
Figure JPOXMLDOC01-appb-T000014
　図１１Ａ～図１１Ｃは、実施例５の撮像レンズ系１０１の縦収差図、像面湾曲図、歪曲収差図である。図１１Ａ～図１１Ｃに示すように、実施例５の撮像レンズ系１０１では、半画角ωが１０７°、Ｆナンバが２．０である。図１１Ａの縦収差図では、横軸は光線が光軸Ｚと交わる位置を示し、縦軸は瞳径での高さを示す。図１１Ｂの像面湾曲図では、横軸は光軸Ｚ方向の距離を示し、縦軸は像高（画角）を示す。図１１Ｂにおいて、Ｓａｇはサジタル面における像面湾曲を示し、Ｔａｎはタンジェンシャル面における像面湾曲を示す。図１１Ｃの歪曲収差図では、横軸は像の歪み量（％）を示し、縦軸は像高（画角）を示す。図１１Ａ～図１１Ｃでは、波長５４６ｎｍの光線によるシミュレーション結果を示してある。 FIGS. 11A to 11C are a longitudinal aberration diagram, a field curvature diagram, and a distortion diagram of the imaging lens system 101 of Example 5. FIG. As shown in FIGS. 11A to 11C, in the imaging lens system 101 of Example 5, the half angle of view ω is 107 ° and the F number is 2.0. In the longitudinal aberration diagram of FIG. 11A, the horizontal axis indicates the position where the light beam intersects the optical axis Z, and the vertical axis indicates the height at the pupil diameter. In the field curvature diagram of FIG. 11B, the horizontal axis indicates the distance in the optical axis Z direction, and the vertical axis indicates the image height (field angle). In FIG. 11B, Sag indicates the field curvature in the sagittal plane, and Tan indicates the field curvature in the tangential plane. In the distortion diagram of FIG. 11C, the horizontal axis indicates the amount of distortion (%) of the image, and the vertical axis indicates the image height (angle of view). FIG. 11A to FIG. 11C show simulation results using light rays having a wavelength of 546 nm.
　表１５に、実施例５の撮像レンズ系１０１の特性値を計算した結果を示す。表１５には、表９と同様の特性値について計算した結果を示す。 Table 15 shows the results of calculating the characteristic values of the imaging lens system 101 of Example 5. Table 15 shows the results calculated for the same characteristic values as in Table 9.
Figure JPOXMLDOC01-appb-T000015
Figure JPOXMLDOC01-appb-T000015
　(実施例６)
　図１２は、実施例６の撮像レンズ系１０１の構成を示す図である。
　実施例６の撮像レンズ系１０１は、物体側から像側に向かって順に、負のパワーを有する第１レンズ群Ｇ１と、正のパワーを有する第２レンズ群Ｇ２と、絞りと、正のパワーを有する第３レンズ群Ｇ３と、から構成される。第１レンズ群Ｇ１は、レンズＬ１１及びレンズＬ１２から構成される。第２レンズ群Ｇ２は、レンズＬ２１から構成される。第３レンズ群Ｇ３は、レンズＬ３１から構成される。実施例６の撮像レンズ系１０１では、レンズＬ１１はガラスレンズであり、レンズＬ１２、レンズＬ２１、及びレンズＬ３１はプラスチックレンズである。 Example 6
FIG. 12 is a diagram illustrating a configuration of the imaging lens system 101 according to the sixth embodiment.
The imaging lens system 101 according to the sixth exemplary embodiment includes, in order from the object side to the image side, a first lens group G1 having a negative power, a second lens group G2 having a positive power, a diaphragm, and a positive power. And a third lens group G3. The first lens group G1 includes a lens L11 and a lens L12. The second lens group G2 includes a lens L21. The third lens group G3 includes a lens L31. In the imaging lens system 101 of Example 6, the lens L11 is a glass lens, and the lens L12, the lens L21, and the lens L31 are plastic lenses.
　レンズＬ１１は、負のパワーを有する球面メニスカスレンズである。レンズＬ１１の物体側レンズ面Ｓ１は正の曲率を有する球面であり、像側レンズ面Ｓ２は正の曲率を有する球面である。物体側レンズ面Ｓ１及び像側レンズ面Ｓ２は像側に凹面を向けている。 The lens L11 is a spherical meniscus lens having negative power. The object side lens surface S1 of the lens L11 is a spherical surface having a positive curvature, and the image side lens surface S2 is a spherical surface having a positive curvature. The object side lens surface S1 and the image side lens surface S2 are concave on the image side.
　レンズＬ１２は、負のパワーを有する非球面レンズである。レンズＬ１２の物体側レンズ面Ｓ３は負の曲率を有する非球面であり、像側レンズ面Ｓ４は正の曲率を有する非球面である。物体側レンズ面Ｓ３は像側に突出する凸形状の曲面部分を有しており、像側レンズ面Ｓ４は物体側に突出する凸形状の曲面部分を有している。 Lens L12 is an aspherical lens having negative power. The object side lens surface S3 of the lens L12 is an aspheric surface having a negative curvature, and the image side lens surface S4 is an aspheric surface having a positive curvature. The object side lens surface S3 has a convex curved surface portion protruding toward the image side, and the image side lens surface S4 has a convex curved surface portion protruding toward the object side.
　レンズＬ２１は、正のパワーを有する非球面レンズである。物体側レンズ面Ｓ５は正の曲率を有する非球面であり、像側レンズ面Ｓ６は正の曲率を有する非球面である。物体側レンズ面Ｓ５は物体側に突出する凸形状の曲面部分を有しており、像側レンズ面Ｓ６は物体側に突出する凸形状の曲面部分を有している。 The lens L21 is an aspheric lens having positive power. The object side lens surface S5 is an aspherical surface having a positive curvature, and the image side lens surface S6 is an aspherical surface having a positive curvature. The object side lens surface S5 has a convex curved surface portion protruding toward the object side, and the image side lens surface S6 has a convex curved surface portion protruding toward the object side.
　レンズＬ３１は、正のパワーを有する非球面レンズである。物体側レンズ面Ｓ８は負の曲率を有する非球面であり、像側レンズ面Ｓ９は負の曲率を有する非球面である。物体側レンズ面Ｓ８は像側に突出する凸形状の曲面部分を有しており、像側レンズ面Ｓ９は像側に突出する凸形状の曲面部分を有している。 The lens L31 is an aspheric lens having positive power. The object side lens surface S8 is an aspherical surface having a negative curvature, and the image side lens surface S9 is an aspherical surface having a negative curvature. The object side lens surface S8 has a convex curved surface portion protruding toward the image side, and the image side lens surface S9 has a convex curved surface portion protruding toward the image side.
　表１６に、撮像レンズ系１０１の各レンズ面のレンズデータを示す。「＊印」がついた面は、非球面であることを示している。 Table 16 shows lens data of each lens surface of the imaging lens system 101. A surface marked with “*” indicates an aspherical surface.
Figure JPOXMLDOC01-appb-T000016
Figure JPOXMLDOC01-appb-T000016
　表１７に、実施例６の撮像レンズ系１０１において、非球面とされたレンズ面の非球面形状を規定するための非球面係数を示す。 Table 17 shows the aspherical coefficients for defining the aspherical shape of the aspherical lens surface in the imaging lens system 101 of Example 6.
Figure JPOXMLDOC01-appb-T000017
Figure JPOXMLDOC01-appb-T000017
　図１３Ａ～図１３Ｃは、実施例６の撮像レンズ系１０１の縦収差図、像面湾曲図、歪曲収差図である。図１３Ａ～図１３Ｃに示すように、実施例６の撮像レンズ系１０１では、半画角ωが１０９°、Ｆナンバが２．０である。図１３Ａの縦収差図では、横軸は光線が光軸Ｚと交わる位置を示し、縦軸は瞳径での高さを示す。図１３Ｂの像面湾曲図では、横軸は光軸Ｚ方向の距離を示し、縦軸は像高（画角）を示す。図１３Ｂにおいて、Ｓａｇはサジタル面における像面湾曲を示し、Ｔａｎはタンジェンシャル面における像面湾曲を示す。図１３Ｃの歪曲収差図では、横軸は像の歪み量（％）を示し、縦軸は像高（画角）を示す。図１３Ａ～図１３Ｃでは、波長５４６ｎｍの光線によるシミュレーション結果を示してある。 FIGS. 13A to 13C are a longitudinal aberration diagram, a field curvature diagram, and a distortion diagram of the imaging lens system 101 of Example 6. FIG. As shown in FIGS. 13A to 13C, in the imaging lens system 101 of Example 6, the half angle of view ω is 109 ° and the F number is 2.0. In the longitudinal aberration diagram of FIG. 13A, the horizontal axis indicates the position where the light beam intersects the optical axis Z, and the vertical axis indicates the height at the pupil diameter. In the field curvature diagram of FIG. 13B, the horizontal axis indicates the distance in the optical axis Z direction, and the vertical axis indicates the image height (field angle). In FIG. 13B, Sag indicates the field curvature in the sagittal plane, and Tan indicates the field curvature in the tangential plane. In the distortion diagram of FIG. 13C, the horizontal axis represents the amount of distortion (%) of the image, and the vertical axis represents the image height (field angle). FIG. 13A to FIG. 13C show simulation results using light rays having a wavelength of 546 nm.
　表１８に、実施例６の撮像レンズ系１０１の特性値を計算した結果を示す。表１８には、表９と同様の特性値について計算した結果を示す。 Table 18 shows the result of calculating the characteristic values of the imaging lens system 101 of Example 6. Table 18 shows the results calculated for the same characteristic values as in Table 9.
Figure JPOXMLDOC01-appb-T000018
Figure JPOXMLDOC01-appb-T000018
　表１９に、実施例１～６の撮像レンズ系１０１において、条件式（１）、（２）及び（４）のパラメータを計算した結果を示す。 Table 19 shows the results of calculating the parameters of conditional expressions (1), (2), and (4) in the imaging lens systems 101 of Examples 1 to 6.
Figure JPOXMLDOC01-appb-T000019
Figure JPOXMLDOC01-appb-T000019
　（撮像装置への適用例）
　図１は、撮像レンズ系１０１を用いた撮像装置１００の構成を示す図である。撮像装置１００は、撮像レンズ系１０１と、カバーガラス１０２と、撮像素子１０３と、を備える。撮像レンズ系１０１と、カバーガラス１０２と、撮像素子１０３と、は筐体（不図示）に収容されている。 (Application example to imaging device)
FIG. 1 is a diagram illustrating a configuration of an imaging apparatus 100 using an imaging lens system 101. The imaging apparatus 100 includes an imaging lens system 101, a cover glass 102, and an imaging element 103. The imaging lens system 101, the cover glass 102, and the imaging element 103 are accommodated in a housing (not shown).
　撮像素子１０３は、受光した光を電気信号に変換する素子であり、例えば、ＣＣＤイメージセンサやＣＭＯＳイメージセンサが用いられる。撮像素子１０３は、撮像レンズ系１０１の結像位置に配置されている。なお、水平画角とは、撮像素子１０３の水平方向に対応する画角である。 The image sensor 103 is an element that converts received light into an electrical signal. For example, a CCD image sensor or a CMOS image sensor is used. The image sensor 103 is disposed at the imaging position of the imaging lens system 101. The horizontal angle of view is an angle of view corresponding to the horizontal direction of the image sensor 103.
　カバーガラス１０２は、撮像素子１０３を異物から保護するために、撮像素子１０３上に設けられている。 The cover glass 102 is provided on the image sensor 103 in order to protect the image sensor 103 from foreign matter.
　なお、本発明は上記実施の形態に限られたものではなく、趣旨を逸脱しない範囲で適宜変更することが可能である。例えば、本発明の撮像レンズ系１０１の用途は、車載カメラや監視カメラに限定されるものではなく、携帯電話等の小型電子機器に搭載する等の他の用途にも用いることができる。 Note that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention. For example, the application of the imaging lens system 101 of the present invention is not limited to an in-vehicle camera or a surveillance camera, and can be used for other applications such as mounting in a small electronic device such as a mobile phone.
　この出願は、２０１４年７月３０日に出願された日本出願特願２０１４－１５４９２４を基礎とする優先権を主張し、その開示の全てをここに取り込む。 This application claims priority based on Japanese Patent Application No. 2014-154924 filed on July 30, 2014, the entire disclosure of which is incorporated herein.
１００　撮像装置
１０１　撮像レンズ
１０２　カバーガラス
１０３　撮像素子
Ｇ１～Ｇ３　第１レンズ群～第３レンズ群
Ｌ１１～Ｌ３１　レンズ DESCRIPTION OF SYMBOLS 100 Image pick-up apparatus 101 Imaging lens 102 Cover glass 103 Image pick-up element G1-G3 1st lens group-3rd lens group L11-L31 Lens

Claims (11)

  1. 　物体側から順に、負のパワーを有する第１レンズ群、正のパワーを有する第２レンズ群、正のパワーを有する第３レンズ群とからなる撮像レンズ系であって、
    　前記第１レンズ群は１枚又は２枚の負レンズからなり、
    　前記第２レンズ群は１枚の正レンズからなり、
    　前記第３レンズ群は１枚の正レンズからなり、
    　レンズ系全体の焦点距離をｆ、
    　前記第３レンズ群の焦点距離をｆ３、
    　としたときに、下記の条件式（１）を満たすことを特徴とする撮像レンズ系。
    　０．９＜ｆ３／ｆ＜２．２　　（１）     An imaging lens system comprising, in order from the object side, a first lens group having negative power, a second lens group having positive power, and a third lens group having positive power,
    The first lens group includes one or two negative lenses,
    The second lens group is composed of one positive lens,
    The third lens group is composed of one positive lens,
    The focal length of the entire lens system is f,
    The focal length of the third lens group is f 3 ,
    An imaging lens system satisfying the following conditional expression (1):
    0.9 <f 3 /f<2.2 (1)
  2. 　請求項１に記載の撮像レンズ系であって、
    　前記第３レンズ群を構成する最も像側のレンズの像側レンズ面は、下記の条件式（２）を満たすことを特徴とする撮像レンズ系。
    　０．９＜ｆＬ３１Ｒ２／ｆ＜２．０　　（２）
    　ただし、ｆＬ３１Ｒ２は第３レンズ群を構成する最も像側のレンズの像側レンズ面の焦点距離であり、以下の式（３）で定義される。
    　１／ｆＬ３１Ｒ２＝－（ｎ－１）／Ｒ　　（３）
    ｎ：第３レンズ群を構成する最も像側のレンズの屈折率
    Ｒ：第３レンズ群を構成する最も像側のレンズの像側レンズ面の曲率半径     The imaging lens system according to claim 1,
    An image pickup lens system, wherein an image side lens surface of a most image side lens constituting the third lens group satisfies the following conditional expression (2).
    0.9 <f L31R2 / f <2.0 (2)
    Here, f L31R2 is the focal length of the image side lens surface of the most image side lens constituting the third lens group, and is defined by the following formula (3).
    1 / f L31R2 = − (n−1) / R (3)
    n: Refractive index of the most image side lens constituting the third lens group R: Radius of curvature of the image side lens surface of the most image side lens constituting the third lens group
  3. 　請求項１又は２に記載の撮像レンズ系であって、
    　前記第１レンズ群は１枚の負レンズからなる
    　ことを特徴とする撮像レンズ系。     The imaging lens system according to claim 1 or 2,
    The imaging lens system, wherein the first lens group includes one negative lens.
  4. 　請求項１又は２に記載の撮像レンズ系であって、
    　前記第１レンズ群は２枚の負レンズからなる
    　ことを特徴とする撮像レンズ系。     The imaging lens system according to claim 1 or 2,
    The imaging lens system, wherein the first lens group includes two negative lenses.
  5. 　請求項１～４のいずれか一項に記載の撮像レンズ系であって、
    　前記第１レンズ群の焦点距離をｆ１、
    　前記第２レンズ群の焦点距離をｆ２、
    　としたときに、下記の条件式（４）を満たすことを特徴とする撮像レンズ系。
    　０．３＜｜ｆ１／ｆ２｜＜１．５　　（４）     The imaging lens system according to any one of claims 1 to 4,
    The focal length of the first lens group is f 1 ,
    The focal length of the second lens group is f 2 ,
    An imaging lens system satisfying the following conditional expression (4):
    0.3 <| f 1 / f 2 | <1.5 (4)
  6. 　請求項１～５のいずれか一項に記載の撮像レンズ系であって、
    　水平画角が１００度以上であることを特徴とする撮像レンズ系。     An imaging lens system according to any one of claims 1 to 5,
    An imaging lens system having a horizontal angle of view of 100 degrees or more.
  7. 　請求項１～６のいずれか一項に記載の撮像レンズ系であって、
    　絞りが前記第２レンズ群と前記第３レンズ群との間にあることを特徴とする撮像レンズ系。     The imaging lens system according to any one of claims 1 to 6,
    An imaging lens system, wherein an aperture is between the second lens group and the third lens group.
  8. 　物体側から順に、負のパワーを有する第１レンズ群、正のパワーを有する第２レンズ群、正のパワーを有する第３レンズ群とからなる撮像レンズ系であって、
    　レンズ系全体の焦点距離をｆ、
    　前記第３レンズ群の焦点距離をｆ３、
    　としたときに、下記の条件式（１）及び（２）を満たすことを特徴とする撮像レンズ系。
    　０．９＜ｆ３／ｆ＜２．２　　（１）
    　０．９＜ｆＬ３１Ｒ２／ｆ＜２．０　　（２）
    　ただし、ｆＬ３１Ｒ２は第３レンズ群を構成する最も像側のレンズの像側レンズ面の焦点距離であり、以下の式（３）で定義される。
    　１／ｆＬ３１Ｒ２＝－（ｎ－１）／Ｒ　　（３）
    ｎ：第３レンズ群を構成する最も像側のレンズの屈折率
    Ｒ：第３レンズ群を構成する最も像側のレンズの像側レンズ面の曲率半径     An imaging lens system comprising, in order from the object side, a first lens group having negative power, a second lens group having positive power, and a third lens group having positive power,
    The focal length of the entire lens system is f,
    The focal length of the third lens group is f 3 ,
    An imaging lens system satisfying the following conditional expressions (1) and (2):
    0.9 <f 3 /f<2.2 (1)
    0.9 <f L31R2 / f <2.0 (2)
    Here, f L31R2 is the focal length of the image side lens surface of the most image side lens constituting the third lens group, and is defined by the following formula (3).
    1 / f L31R2 = − (n−1) / R (3)
    n: Refractive index of the most image side lens constituting the third lens group R: Radius of curvature of the image side lens surface of the most image side lens constituting the third lens group
  9. 　物体側から順に、負のパワーを有する第１レンズ群、正のパワーを有する第２レンズ群、正のパワーを有する第３レンズ群とからなる撮像レンズ系であって、
    　レンズ系全体の焦点距離をｆ、
    　前記第１レンズ群の焦点距離をｆ１、
    　前記第２レンズ群の焦点距離をｆ２、
    　前記第３レンズ群の焦点距離をｆ３、
    　としたときに、下記の条件式（１）及び（４）を満たすことを特徴とする撮像レンズ系。
    　０．９＜ｆ３／ｆ＜２．２　　（１）
    　０．３＜｜ｆ１／ｆ２｜＜１．５　　（４）     An imaging lens system comprising, in order from the object side, a first lens group having negative power, a second lens group having positive power, and a third lens group having positive power,
    The focal length of the entire lens system is f,
    The focal length of the first lens group is f 1 ,
    The focal length of the second lens group is f 2 ,
    The focal length of the third lens group is f 3 ,
    An imaging lens system satisfying the following conditional expressions (1) and (4):
    0.9 <f 3 /f<2.2 (1)
    0.3 <| f 1 / f 2 | <1.5 (4)
  10. 　請求項８又は９に記載の撮像レンズ系であって、
    　絞りが前記第２レンズ群と前記第３レンズ群との間にある
    　ことを特徴とする撮像レンズ系。     The imaging lens system according to claim 8 or 9, wherein
    An imaging lens system, wherein an aperture is between the second lens group and the third lens group.
  11. 　請求項１～１０のいずれか一項に記載の撮像レンズ系と、
    　前記撮像レンズ系の焦点位置に配置された撮像素子と、を有する
    　ことを特徴とする撮像装置。     An imaging lens system according to any one of claims 1 to 10;
    An image pickup device disposed at a focal position of the image pickup lens system.
PCT/JP2015/003187 2014-07-30 2015-06-25 Image pickup lens system and image pickup device WO2016017065A1 (en)

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