WO2011161971A1 - Image pickup optical system - Google Patents

Image pickup optical system Download PDF

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Publication number
WO2011161971A1
WO2011161971A1 PCT/JP2011/003607 JP2011003607W WO2011161971A1 WO 2011161971 A1 WO2011161971 A1 WO 2011161971A1 JP 2011003607 W JP2011003607 W JP 2011003607W WO 2011161971 A1 WO2011161971 A1 WO 2011161971A1
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Prior art keywords
lens
optical system
imaging optical
image
shows
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PCT/JP2011/003607
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French (fr)
Japanese (ja)
Inventor
典久 坂上
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ナルックス株式会社
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Publication date
Application filed by ナルックス株式会社 filed Critical ナルックス株式会社
Priority to JP2011545580A priority Critical patent/JP4992004B2/en
Publication of WO2011161971A1 publication Critical patent/WO2011161971A1/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
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
    • G02B13/002—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
    • G02B13/0035—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having three lenses

Definitions

  • the present invention relates to an imaging optical system used for a digital camera, a mobile phone with an imaging function, and the like.
  • a high-pixel imaging optical system for realizing high image quality is composed of four or more lenses including an achromatic lens using a high dispersion material. By using a diffraction grating, it is possible to remove the achromatic lens.
  • a three-lens imaging optical system that realizes high image quality is as high as or better than a four-lens imaging optical system in terms of aberrations other than chromatic aberration such as spherical aberration and curvature of field, peripheral light amount ratio, and brightness It is necessary to have performance.
  • Patent Document 1 discloses a three-element imaging system including, in order from the object side, a positive first lens, a second lens having a concave surface on the object side, and a negative third lens.
  • This three-element imaging system is small and has a small field curvature.
  • the F number of this three-element imaging system is 3.5, and compared with the imaging optical system of F number 2.8 that is generally used, the contrast near the center is lowered and the image quality is lowered. To do.
  • Patent Document 2 discloses a three-element imaging system including a positive first lens in order from the object side, a positive or negative second lens having a concave surface facing the object side, and a positive or negative third lens.
  • This three-lens imaging system includes a small one having an F number of 3.0 or less.
  • the spherical aberration of this three-element imaging system is relatively large, and the image quality deteriorates due to the deterioration of the spherical aberration.
  • Patent Document 1 Japanese Unexamined Patent Application Publication No. 2008-276200 Patent Document 2 Japanese Unexamined Patent Application Publication No. 2007-264181
  • the imaging optical system includes a positive first lens having a diffraction grating on the image side from the object side to the image side, a second lens that is a meniscus lens having a convex surface facing the image side, and a negative meniscus lens.
  • An imaging optical system that includes a third lens and whose diaphragm is disposed on the object side of the image side surface of the first lens, D12 is a distance on the optical axis between the first lens and the second lens, TTL is the distance from the object-side vertex of the first lens to the image plane, ⁇ 1 is the power of the first lens, ⁇ 2 is the power of the second lens, and ⁇ is the power of the first lens, the second lens, and the third lens.
  • the combined power, Fno is the F number of the optical system, and r1 is the radius of curvature of the object side surface of the first lens. 0.18 ⁇ D12 ⁇ ⁇ ⁇ 0.22 (1) 1.1 ⁇ TTL ⁇ ⁇ ⁇ 1.22 (2) Fno ⁇ 3.0 (3) 0.46 ⁇ r1 ⁇ ⁇ ⁇ 0.49 (4) 0.8 ⁇ / ⁇ 1 ⁇ 1.0 (5)
  • the imaging optical system it is easy to reduce the size of the optical system by using the first lens as a positive lens.
  • the first lens By attaching a diffraction grating to the image side of the first lens, axial chromatic aberration is improved and high resolution can be realized.
  • the second lens By making the second lens a meniscus lens having a convex surface facing the image side, field curvature can be reduced.
  • the third lens By making the third lens a negative lens, the exit pupil position can be brought to the object side, and the incident angle to the peripheral edge of the image element can be reduced while maintaining the back focus.
  • the optical system can be miniaturized by disposing the stop closer to the object side than the image side surface of the first lens. Furthermore, by satisfying the formulas (1) to (6), an optical system that is small and easy to manufacture, has a small curvature of field, and generates a bright, high-quality image can be obtained.
  • the second lens is a zero-power meniscus lens in which the negative power of the image side surface increases from the paraxial region toward the periphery.
  • the negative power of the image side surface of the second lens increases from the paraxial region toward the periphery, the light beam around the central light beam is maintained while maintaining the light beam height around the peripheral light beam. Since the height can be reduced, the peripheral light quantity ratio can be increased. Further, by setting the power of the second lens to 0, it is possible to reduce the eccentric sensitivity of the second lens with respect to the first lens during assembly, and it is possible to reduce the manufacturing cost. Further, even if a highly dispersed material is used, axial chromatic aberration is not changed, and peripheral chromatic aberration can be improved.
  • the first lens is a convex flat or biconvex lens in the paraxial region.
  • the object side surface of the third lens has positive power in the paraxial region and the peripheral region, and negative power in the intermediate region between the paraxial region and the peripheral region.
  • the image plane Since the height of the central ray of the peripheral rays can be increased while the curvature is reduced, the incident angle of the rays on the peripheral edge of the image sensor can be reduced.
  • the image side surface of the third lens has negative power in the paraxial region and positive power in the peripheral region.
  • the image side surface of the third lens is formed so as to have a negative power in the paraxial region and a positive power in the peripheral region, and the paraxial region of the first to third lenses is made uneven.
  • ⁇ 3 is the power of the third lens. -3.3 ⁇ / ⁇ 3 ⁇ -2.6 (7) Satisfied.
  • v d 1 is the Abbe number of the first lens material on the d-line (wavelength 587.6 nm)
  • v d 3 is the third lens material d-line (wavelength 587.6 nm).
  • N d 1 is the refractive index of the first lens material at the d-line (wavelength 587.6 nm)
  • n d 3 is the refraction of the third lens material at the d-line (wavelength 587.6 nm).
  • Resin materials such as olefins can be used for the first lens and the third lens, and the cost can be reduced compared to the case of using glass.
  • n d 2 is the refractive index of the second lens material at the d-line (wavelength 587.6 nm)
  • r 3 is the radius of curvature on the second lens object side
  • r 4 is the second lens.
  • the curvature radius on the image side, D2 is the center thickness of the second lens.
  • Equation (10) represents the power of the second lens.
  • the spherical aberration increases.
  • the power of the second lens it is possible to reduce the eccentricity sensitivity of the second lens with respect to the first lens during assembly, thereby reducing the manufacturing cost. Further, even if a highly dispersed material is used, axial chromatic aberration is not changed, and peripheral chromatic aberration can be improved.
  • ⁇ DOE is the power of the diffraction grating of the first lens. 0.05 ⁇ DOE / ⁇ ⁇ 0.07 (11) Satisfied.
  • the depth of focus becomes shallow, the eccentricity sensitivity at the time of assembly increases, and the manufacturing cost increases.
  • the F number is larger than the upper limit value of the equation (12), the resolution is deteriorated due to the diffraction limit.
  • FIG. 1 is a diagram illustrating a configuration of an imaging optical system according to Example 1.
  • FIG. FIG. 6 is a diagram illustrating aberrations of the imaging optical system according to Example 1.
  • FIG. 6 is a diagram illustrating a configuration of an imaging optical system according to a second embodiment.
  • FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 2.
  • 6 is a diagram illustrating a configuration of an imaging optical system according to Example 3.
  • FIG. FIG. 6 is a diagram illustrating aberrations of the imaging optical system according to Example 3.
  • FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 4.
  • FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 4.
  • FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 5.
  • FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 5.
  • FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 6.
  • FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 6.
  • FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 7.
  • FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 7.
  • FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 8.
  • FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 8.
  • FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 9.
  • FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 9.
  • FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 9. FIG.
  • FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 10.
  • FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 10.
  • FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 11.
  • FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 11.
  • FIG. 16 is a diagram illustrating a configuration of an imaging optical system according to Example 12.
  • FIG. 14 shows aberrations of the image pickup optical system according to the twelfth embodiment.
  • FIG. 16 is a diagram illustrating a configuration of an imaging optical system according to Example 13. It is a figure which shows the aberration of the imaging optical system by Example 13.
  • FIG. 16 is a diagram illustrating a configuration of an imaging optical system according to Example 14.
  • FIG. 16 is a diagram illustrating a configuration of an imaging optical system according to Example 15.
  • FIG. 20 is a diagram illustrating aberrations of the image pickup optical system according to the fifteenth embodiment.
  • FIG. 1 is a diagram showing a configuration of an imaging optical system according to an embodiment of the present invention.
  • the imaging optical system according to the present embodiment light that has passed through the first lens E1, the second lens E2, and the third lens E3 from the object side to the image side passes through the glass plate E4 and reaches the image plane IS.
  • An imaging optical system includes a first lens that is a positive lens having a diffraction grating on the image side from the object side to the image side, and a meniscus lens having a convex surface on the image side. And a third lens which is a negative meniscus lens. The stop is disposed closer to the object side than the image side surface of the first lens.
  • the second lens as a meniscus lens having a convex surface facing the image side, curvature of field can be reduced.
  • the exit pupil position can be brought to the object side, and the incident angle to the peripheral edge of the image element can be reduced while maintaining the back focus.
  • the optical system can be miniaturized by disposing the aperture stop on the object side with respect to the image side surface of the first lens.
  • the product of the distance D12 on the optical axis between the first and second lenses and the combined power ⁇ of the three lenses is an optical system according to an embodiment of the present invention. 0.18 ⁇ D12 ⁇ ⁇ ⁇ 0.22 (1) Configured to meet.
  • D12 ⁇ ⁇ is lower than the lower limit value of the expression (1), the eccentricity sensitivity of the second lens with respect to the first lens during assembly increases, and the manufacturing cost increases.
  • D12 ⁇ ⁇ exceeds the upper limit value of the formula (1) the optical system becomes large.
  • the product of the distance TTL from the object-side vertex of the first lens to the image plane and the combined power ⁇ of the three lenses is an optical system according to an embodiment of the present invention.
  • 1.1 ⁇ TTL ⁇ ⁇ ⁇ 1.22 (2) Configured to meet.
  • TTL ⁇ ⁇ is lower than the lower limit value of the expression (2), resolution degradation due to curvature of field of the optical system increases.
  • TTL ⁇ ⁇ exceeds the upper limit value of the formula (2), the optical system becomes large.
  • the lens power means the power of the lens near the paraxial axis.
  • F number Fno An optical system according to an embodiment of the present invention includes: Fno ⁇ 3.0 (3) Configured to meet. When Fno is larger than 3, resolution is degraded due to the diffraction limit.
  • the product of the radius of curvature r1 of the object side surface of the first lens and the combined power ⁇ of the three lenses is an optical system according to an embodiment of the present invention. 0.46 ⁇ r1 ⁇ ⁇ ⁇ 0.49 (4) Configured to meet.
  • r1 ⁇ ⁇ is less than the lower limit value of the equation (4), spherical aberration increases and resolution is degraded. Further, when the F number is increased to reduce the brightness in order to reduce the spherical aberration, the contrast is lowered. Thus, in any case, the image quality is degraded. If r1 ⁇ ⁇ exceeds the upper limit value of the equation (4), the optical system becomes large.
  • Ratio of combined power [phi] of the three lenses and power [phi] 1 of the first lens The optical system according to the embodiment of the present invention is 0.8 ⁇ / ⁇ 1 ⁇ 1.0 (5) Configured to meet. If ⁇ / ⁇ 1 is below the lower limit of the equation (5), the eccentricity sensitivity of the second lens to the first lens during assembly increases, and the manufacturing cost increases. When ⁇ / ⁇ 1 exceeds the upper limit value of the equation (5), the optical system becomes large.
  • the absolute value of the ratio of the power [phi] 2 of the second lens and the combined power [phi] of the three lenses is the optical system according to the embodiment of the present invention.
  • the lenses are all formed of a plastic (resin) material. Therefore, all the lenses can be manufactured by molding, which is suitable for mass production.
  • the material of the first and third lenses is a cycloolefin polymer (COP) resin
  • the material of the second lens is a cycloolefin polymer (COP) resin or a polycarbonate (PC) resin or a cycloolefin copolymer (COC).
  • COP cycloolefin polymer
  • PC polycarbonate
  • COC cycloolefin copolymer
  • Table 1 and Table 2 of the imaging optical system according to the examples are tables showing the specifications of the imaging optical systems of Examples 1 to 15.
  • the unit of length is millimeter.
  • FIG. 1 is a diagram illustrating a configuration of an imaging optical system according to the first embodiment.
  • the imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side.
  • the light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
  • FIG. 2 is a diagram illustrating aberrations of the image pickup optical system according to the first embodiment.
  • FIG. 2A is a diagram showing axial chromatic aberration.
  • the horizontal axis of Fig.2 (a) shows the focus position (a unit is a millimeter) of an optical axis direction.
  • shaft of Fig.2 (a) shows the passage position in the aperture_diaphragm
  • FIG. 2B is a diagram showing astigmatism and field curvature.
  • the horizontal axis of FIG.2 (b) shows the focus position of an optical axis direction (a unit is a millimeter).
  • shaft of FIG.2 (b) shows image height (a unit is a millimeter).
  • the dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane.
  • FIG. 2C is a diagram showing distortion.
  • the horizontal axis of FIG.2 (c) shows a distortion aberration (distortion).
  • shaft of FIG.2 (c) shows image height (a unit is a millimeter).
  • Table 3 is a table showing lens data of the imaging optical system according to Example 1.
  • the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive.
  • the surface interval of the second surface is the interval between the second surface and the third surface (the image side surface of the second lens).
  • Table 4 is a table showing coefficients and constants of expressions representing the aspheric shapes of the second surface to the seventh surface.
  • the aspherical shape is a quadratic curve represented by the following formula: That is, it is an optical axis symmetric rotation surface rotated about the z axis.
  • k is a constant that determines the shape of the quadratic curve
  • c is the central curvature.
  • a i is a correction coefficient.
  • R on the second surface corresponds to r1.
  • A10E-N is A ⁇ 10 -N Represents.
  • Table 5 is a table showing coefficients of the optical path difference function of the diffraction grating.
  • the optical path difference function is defined by the following equation.
  • FIG. 3 is a diagram illustrating a configuration of the imaging optical system according to the second embodiment.
  • the imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side.
  • the light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
  • FIG. 4 is a diagram illustrating aberrations of the imaging optical system according to the second embodiment.
  • FIG. 4A is a diagram showing axial chromatic aberration.
  • the horizontal axis of Fig.4 (a) shows the focus position (a unit is a millimeter) of an optical axis direction.
  • the vertical axis in FIG. 4A indicates the passing position in the aperture of the light beam. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop.
  • FIG. 4B is a diagram showing astigmatism and field curvature.
  • the horizontal axis of FIG.4 (b) shows the focus position of an optical axis direction (a unit is a millimeter).
  • shaft of FIG.4 (b) shows image height (a unit is a millimeter).
  • the dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane.
  • FIG. 4C is a diagram showing distortion.
  • the horizontal axis of FIG.4 (c) shows a distortion aberration (distortion).
  • shaft of FIG.4 (c) shows image height (a unit is a millimeter).
  • Table 6 is a table showing lens data of the imaging optical system according to Example 2.
  • the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive.
  • the surface interval of the second surface is the interval between the second surface and the third surface (the image side surface of the second lens).
  • Table 7 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
  • Table 8 is a table showing coefficients of the optical path difference function of the diffraction grating.
  • FIG. 5 is a diagram illustrating a configuration of an imaging optical system according to the third embodiment.
  • the imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side.
  • the light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
  • FIG. 6 is a diagram illustrating aberrations of the image pickup optical system according to the third embodiment.
  • FIG. 6A is a diagram showing axial chromatic aberration.
  • the horizontal axis of Fig.6 (a) shows the focus position (a unit is a millimeter) of an optical axis direction.
  • shaft of Fig.6 (a) shows the passage position in the aperture_diaphragm
  • FIG. 6B is a diagram showing astigmatism and field curvature.
  • the horizontal axis of FIG.6 (b) shows the focus position of an optical axis direction (a unit is a millimeter).
  • shaft of FIG.6 (b) shows image height (a unit is a millimeter).
  • the dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane.
  • FIG. 6C is a diagram showing distortion.
  • the horizontal axis of FIG.6 (c) shows a distortion aberration (distortion).
  • shaft of FIG.6 (c) shows image height (a unit is a millimeter).
  • Table 9 is a table showing lens data of the imaging optical system according to Example 3.
  • the diaphragm surface interval is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive.
  • the surface interval of the second surface is the interval between the second surface and the third surface (the image side surface of the second lens).
  • Table 10 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
  • Table 11 is a table showing the coefficients of the optical path difference function of the diffraction grating.
  • FIG. 7 is a diagram illustrating a configuration of an imaging optical system according to the fourth embodiment.
  • the imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side.
  • the light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
  • FIG. 8 is a diagram illustrating aberrations of the imaging optical system according to the fourth example.
  • FIG. 8A is a diagram showing axial chromatic aberration.
  • the horizontal axis of Fig.8 (a) shows the focus position (a unit is a millimeter) of an optical axis direction.
  • shaft of Fig.8 (a) shows the passage position in the aperture_diaphragm
  • FIG. 8B is a diagram showing astigmatism and field curvature.
  • the horizontal axis of FIG.8 (b) shows the focus position of an optical axis direction (a unit is a millimeter).
  • shaft of FIG.8 (b) shows image height (a unit is a millimeter).
  • the dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane.
  • FIG. 8C is a diagram showing distortion.
  • the horizontal axis of FIG.8 (c) shows a distortion aberration (distortion).
  • shaft of FIG.8 (c) shows image height (a unit is a millimeter).
  • Table 12 is a table showing lens data of the imaging optical system according to Example 4.
  • the distance between the surfaces of the diaphragms is the position of the second surface when the position of the diaphragm is a reference and the image side is positive.
  • the surface interval of the second surface is the interval between the second surface and the third surface (the image side surface of the second lens).
  • Table 13 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
  • Table 14 is a table
  • FIG. 9 is a diagram illustrating the configuration of the imaging optical system according to the fifth embodiment.
  • the imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side.
  • the light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
  • FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to the fifth example.
  • FIG. 10A is a diagram showing axial chromatic aberration.
  • the horizontal axis of Fig.10 (a) shows the focus position (a unit is a millimeter) of an optical axis direction.
  • shaft of Fig.10 (a) shows the passage position in the aperture_diaphragm
  • FIG. 10B is a diagram showing astigmatism and curvature of field.
  • the horizontal axis of FIG.10 (b) shows the focus position of an optical axis direction (a unit is a millimeter).
  • shaft of FIG.10 (b) shows image height (a unit is a millimeter).
  • the dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane.
  • FIG.10 (c) is a figure which shows a distortion aberration.
  • the horizontal axis of FIG.10 (c) shows a distortion aberration (distortion).
  • shaft of FIG.10 (c) shows image height (a unit is a millimeter).
  • Table 15 is a table showing lens data of the imaging optical system according to Example 5.
  • the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive.
  • the surface interval of the second surface is the interval between the second surface and the third surface (the image side surface of the second lens).
  • Table 16 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
  • Table 17 is a table showing coefficients of the optical path difference function of the diffraction grating.
  • FIG. 11 is a diagram illustrating a configuration of an imaging optical system according to the sixth embodiment.
  • the imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side.
  • the light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
  • FIG. 12 is a diagram illustrating aberrations of the imaging optical system according to the sixth example.
  • FIG. 12A is a diagram showing axial chromatic aberration.
  • the horizontal axis of Fig.12 (a) shows the focus position (a unit is a millimeter) of an optical axis direction.
  • shaft of Fig.12 (a) shows the passage position in the aperture_diaphragm
  • FIG. 12B is a diagram showing astigmatism and curvature of field.
  • the horizontal axis of FIG.12 (b) shows the focus position of an optical axis direction (a unit is a millimeter).
  • shaft of FIG.12 (b) shows image height (a unit is a millimeter).
  • the dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane.
  • FIG. 12C is a diagram showing distortion.
  • the horizontal axis of FIG.12 (c) shows a distortion aberration (distortion).
  • shaft of FIG.12 (c) shows image height (a unit is a millimeter).
  • Table 18 is a table showing lens data of the imaging optical system according to Example 6.
  • the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive.
  • the surface interval of the second surface is the interval between the second surface and the third surface (the image side surface of the second lens).
  • Table 19 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
  • Table 20 is a table
  • FIG. 13 is a diagram illustrating a configuration of an imaging optical system according to the seventh embodiment.
  • the imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side.
  • the light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
  • FIG. 14 is a diagram illustrating aberrations of the image pickup optical system according to the seventh embodiment.
  • FIG. 14A shows axial chromatic aberration.
  • the horizontal axis of Fig.14 (a) shows the focus position (a unit is a millimeter) of an optical axis direction.
  • shaft of Fig.14 (a) shows the passage position in the aperture_diaphragm
  • FIG. 14B is a diagram showing astigmatism and curvature of field.
  • the horizontal axis of FIG.14 (b) shows the focus position of an optical axis direction (a unit is a millimeter).
  • shaft of FIG.14 (b) shows image height (a unit is a millimeter).
  • the dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane.
  • FIG. 14C is a diagram showing distortion.
  • the horizontal axis of FIG.14 (c) shows a distortion aberration (distortion).
  • shaft of FIG.14 (c) shows image height (a unit is a millimeter).
  • Table 21 is a table showing lens data of the imaging optical system according to Example 7.
  • the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive.
  • the surface interval of the second surface is the interval between the second surface and the third surface (the image side surface of the second lens).
  • Table 22 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
  • Table 23 is a table showing coefficients of the optical path difference function of the diffraction grating.
  • FIG. 15 is a diagram illustrating a configuration of an imaging optical system according to the eighth embodiment.
  • the imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side.
  • the light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
  • FIG. 16 is a diagram showing aberrations of the image pickup optical system according to the eighth embodiment.
  • FIG. 16A is a diagram showing axial chromatic aberration.
  • the horizontal axis of Fig.16 (a) shows the focus position (a unit is a millimeter) of an optical axis direction.
  • shaft of Fig.16 (a) shows the passage position in the aperture_diaphragm
  • FIG. 16B is a diagram showing astigmatism and field curvature.
  • FIG. 16B indicates the focal position in the optical axis direction (unit: millimeter).
  • shaft of FIG.16 (b) shows image height (a unit is a millimeter).
  • the dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane.
  • FIG. 16C is a diagram illustrating distortion.
  • the horizontal axis of FIG.16 (c) shows a distortion aberration (distortion).
  • shaft of FIG.16 (c) shows image height (a unit is a millimeter).
  • Table 24 is a table showing lens data of the imaging optical system according to Example 8.
  • the diaphragm surface interval is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive.
  • the surface interval of the second surface is the interval between the second surface and the third surface (the image side surface of the second lens).
  • Table 25 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
  • Table 26 is a table
  • FIG. 17 is a diagram illustrating the configuration of the imaging optical system according to the ninth embodiment.
  • the imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side.
  • the light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
  • FIG. 18 is a diagram illustrating aberrations of the imaging optical system according to the ninth example.
  • FIG. 18A is a diagram showing axial chromatic aberration.
  • the horizontal axis of Fig.18 (a) shows the focus position (a unit is a millimeter) of an optical axis direction.
  • shaft of Fig.18 (a) shows the passage position in the aperture_diaphragm
  • FIG. 18B is a diagram showing astigmatism and field curvature.
  • the horizontal axis of FIG.18 (b) shows the focus position of an optical axis direction (a unit is a millimeter).
  • shaft of FIG.18 (b) shows image height (a unit is a millimeter).
  • the dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane.
  • FIG. 18C is a diagram showing distortion.
  • the horizontal axis of FIG.18 (c) shows a distortion aberration (distortion).
  • shaft of FIG.18 (c) shows image height (a unit is a millimeter).
  • Table 27 is a table showing lens data of the imaging optical system according to Example 9.
  • the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive.
  • the surface interval of the second surface is the interval between the second surface and the third surface (the image side surface of the second lens).
  • Table 28 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
  • Table 29 is a table showing coefficients of the optical path difference function of the diffraction grating.
  • FIG. 19 is a diagram illustrating the configuration of the imaging optical system according to the tenth embodiment.
  • the imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side.
  • the light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
  • FIG. 20 is a diagram illustrating aberrations of the imaging optical system according to the tenth embodiment.
  • FIG. 20A is a diagram showing axial chromatic aberration.
  • the horizontal axis of Fig.20 (a) shows the focus position (a unit is a millimeter) of an optical axis direction.
  • the vertical axis in FIG. 20A indicates the passage position of the light beam in the aperture stop. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop.
  • FIG. 20B is a diagram showing astigmatism and curvature of field.
  • the horizontal axis in FIG. 20B indicates the focal position in the optical axis direction (unit: millimeter).
  • FIG. 20B indicates the image height (unit: millimeter).
  • the dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane.
  • FIG.20 (c) is a figure which shows a distortion aberration.
  • the horizontal axis of FIG.20 (c) shows a distortion aberration (distortion).
  • shaft of FIG.20 (c) shows image height (a unit is a millimeter).
  • Table 30 is a table showing lens data of the imaging optical system according to Example 10.
  • the diaphragm surface interval is the position of the second surface when the position of the diaphragm is a reference and the image side is positive.
  • the surface interval of the second surface is the interval between the second surface and the third surface (the image side surface of the second lens).
  • Table 31 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
  • Table 32 is a table
  • FIG. 21 is a diagram illustrating the configuration of the imaging optical system according to the eleventh embodiment.
  • the imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side.
  • the light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
  • FIG. 22 shows aberrations of the image pickup optical system according to the eleventh embodiment.
  • FIG. 22A is a diagram showing axial chromatic aberration.
  • the horizontal axis of Fig.22 (a) shows the focus position (a unit is a millimeter) of an optical axis direction.
  • shaft of Fig.22 (a) shows the passage position in the aperture_diaphragm
  • FIG. 22B is a diagram showing astigmatism and field curvature.
  • the horizontal axis of FIG.22 (b) shows the focus position of an optical axis direction (a unit is a millimeter).
  • shaft of FIG.22 (b) shows image height (a unit is a millimeter).
  • the dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane.
  • FIG. 22C is a diagram showing distortion.
  • the horizontal axis of FIG.22 (c) shows a distortion aberration (distortion).
  • shaft of FIG.22 (c) shows image height (a unit is a millimeter).
  • Table 33 is a table showing lens data of the imaging optical system according to Example 11.
  • the diaphragm surface interval is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive.
  • the surface interval of the second surface is the interval between the second surface and the third surface (the image side surface of the second lens).
  • Table 34 is a table showing the coefficients and constants of the expressions representing the aspherical shapes of the second surface to the seventh surface.
  • Table 35 is a table
  • FIG. 23 is a diagram illustrating the configuration of the imaging optical system according to the twelfth embodiment.
  • the imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side.
  • the light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
  • FIG. 24 is a diagram showing aberrations of the image pickup optical system according to the twelfth embodiment.
  • FIG. 24A is a diagram showing axial chromatic aberration.
  • the horizontal axis of Fig.24 (a) shows the focus position (a unit is a millimeter) of an optical axis direction.
  • shaft of Fig.24 (a) shows the passage position in the aperture_diaphragm
  • FIG. 24B is a diagram showing astigmatism and field curvature.
  • the horizontal axis of FIG.24 (b) shows the focus position of an optical axis direction (a unit is a millimeter).
  • shaft of FIG.24 (b) shows image height (a unit is a millimeter).
  • the dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane.
  • FIG. 24C is a diagram showing distortion.
  • the horizontal axis of FIG.24 (c) shows a distortion aberration (distortion).
  • shaft of FIG.24 (c) shows image height (a unit is a millimeter).
  • Table 36 is a table showing lens data of the imaging optical system according to Example 12.
  • the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive.
  • the surface interval of the second surface is the interval between the second surface and the third surface (the image side surface of the second lens).
  • Table 37 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
  • Table 38 is a table
  • FIG. 25 is a diagram illustrating the configuration of the imaging optical system according to the thirteenth embodiment.
  • the imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side.
  • the light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
  • FIG. 26 is a diagram illustrating aberrations of the imaging optical system according to the thirteenth embodiment.
  • FIG. 26A is a diagram showing axial chromatic aberration.
  • the horizontal axis of Fig.26 (a) shows the focus position (a unit is a millimeter) of an optical axis direction.
  • shaft of Fig.26 (a) shows the passage position in the aperture_diaphragm
  • FIG. 26B is a diagram showing astigmatism and curvature of field.
  • the horizontal axis of FIG.26 (b) shows the focus position of an optical axis direction (a unit is a millimeter).
  • shaft of FIG.26 (b) shows image height (a unit is a millimeter).
  • the dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane.
  • FIG. 26C is a diagram showing distortion.
  • the horizontal axis of FIG.26 (c) shows a distortion aberration (distortion).
  • shaft of FIG.26 (c) shows image height (a unit is a millimeter).
  • Table 39 is a table showing lens data of the imaging optical system according to Example 13.
  • the diaphragm surface interval is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive.
  • the surface interval of the second surface is the interval between the second surface and the third surface (the image side surface of the second lens).
  • Table 40 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
  • Table 41 is a table
  • FIG. 27 is a diagram illustrating the configuration of the imaging optical system according to the fourteenth embodiment.
  • the imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side.
  • the light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
  • FIG. 28 is a diagram showing aberrations of the imaging optical system according to Example 14.
  • FIG. 28A is a diagram showing axial chromatic aberration.
  • the horizontal axis of Fig.28 (a) shows the focus position (a unit is a millimeter) of an optical axis direction.
  • shaft of Fig.28 (a) shows the passage position in the aperture_diaphragm
  • FIG. 28B is a diagram showing astigmatism and curvature of field.
  • FIG. 28 (b) shows the focus position of an optical axis direction (a unit is a millimeter).
  • shaft of FIG.28 (b) shows image height (a unit is a millimeter).
  • the dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane.
  • FIG. 28 (c) is a diagram showing distortion aberration.
  • the horizontal axis of FIG.28 (c) shows a distortion aberration (distortion).
  • shaft of FIG.28 (c) shows image height (a unit is a millimeter).
  • Table 42 is a table showing lens data of the imaging optical system according to Example 14.
  • the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive.
  • the surface interval of the second surface is the interval between the second surface and the third surface (the image side surface of the second lens).
  • Table 43 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
  • Table 44 is a table
  • FIG. 29 is a diagram illustrating the configuration of the imaging optical system according to the fifteenth embodiment.
  • the imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side.
  • the light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
  • FIG. 30 is a diagram illustrating aberrations of the imaging optical system according to the fifteenth embodiment.
  • FIG. 30A is a diagram showing axial chromatic aberration.
  • the horizontal axis of Fig.30 (a) shows the focus position (a unit is a millimeter) of an optical axis direction.
  • the vertical axis in FIG. 30 (a) indicates the passage position of the light beam. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop.
  • FIG. 30B is a diagram showing astigmatism and curvature of field.
  • the horizontal axis of FIG.30 (b) shows the focus position of an optical axis direction (a unit is a millimeter).
  • shaft of FIG.30 (b) shows image height (a unit is a millimeter).
  • the dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane.
  • FIG.30 (c) is a figure which shows a distortion aberration.
  • the horizontal axis of FIG.30 (c) shows a distortion aberration (distortion).
  • shaft of FIG.30 (c) shows image height (a unit is a millimeter).
  • Table 45 is a table showing lens data of the imaging optical system according to Example 15.
  • the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive.
  • the surface interval of the second surface is the interval between the second surface and the third surface (the image side surface of the second lens).
  • Table 46 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the fifth surface and the seventh surface.
  • Table 47 is a table showing coefficients of the optical path difference function of the diffraction grating.
  • Table 48 is a table
  • the special surface shape is a quadratic curve represented by the following equation: That is, it is an optical axis symmetric rotation surface rotated about the z axis.
  • k j is a constant that determines the shape of the quadratic curve
  • c j is the center curvature
  • d j is a constant that determines the position of the surface.
  • a ij is a correction coefficient.
  • the special surface is composed of a central region including the optical axis and a belt-like region around it.

Abstract

Provided is an image pickup optical system configured from three lenses and having optical properties, such as aberration, peripheral light amount ratio, and brightness, equal to or higher than those of an image pickup optical system configured from four lenses. Specifically provided is an image pickup optical system which comprises, from the object side to the image side, a positive first lens with a diffraction grating on the image side, a second lens that is a meniscus lens with a convex surface directed to the image side, and a third lens that is a negative meniscus lens, and in which a stop is disposed closer to the object side than the surface on the image side of the first lens. The image pickup optical system satisfies the following expressions: 0.18<D12×φ<0.22 (1) 1.1<TTL×φ<1.22 (2) Fno<3.0 (3) 0.46<r1×φ<0.49 (4) 0.8<φ/φ1<1.0 (5) |φ2/φ|<0.1 (6) Where D12 is the distance on the optical axis between the first lens and the second lens, TTL is the distance from the vertex on the object side of the first lens to the image surface, φ1 is the power of the first lens, φ2 is the power of the second lens, φ is the combined power of the first lens, the second lens, and the third lens, Fno is the f-number of the optical system, and r1 is the curvature radius of the surface on the object side of the first lens.

Description

撮像光学系Imaging optical system
　本発明は、デジタルカメラ、撮像機能付き携帯電話などに使用される撮像光学系に関する。 The present invention relates to an imaging optical system used for a digital camera, a mobile phone with an imaging function, and the like.
　携帯電話などに使用される撮像光学系には、高画質、小型、低コストであることに対するニーズがある。高画質を実現するための高画素の撮像光学系は、高分散材料を使用する色消し用のレンズを含む、４枚以上のレンズから構成される。回折格子を使用することにより、色消し用のレンズを取り除くことが可能である。しかし、高画質を実現する３枚構成の撮像光学系は、球面収差や像面湾曲などの色収差以外の収差、周辺光量比、明るさなどで４枚構成の撮像光学系と同等以上の高い光学性能を備える必要がある。 There is a need for an imaging optical system used for a mobile phone or the like for high image quality, small size, and low cost. A high-pixel imaging optical system for realizing high image quality is composed of four or more lenses including an achromatic lens using a high dispersion material. By using a diffraction grating, it is possible to remove the achromatic lens. However, a three-lens imaging optical system that realizes high image quality is as high as or better than a four-lens imaging optical system in terms of aberrations other than chromatic aberration such as spherical aberration and curvature of field, peripheral light amount ratio, and brightness It is necessary to have performance.
　特許文献１は、物体側から順に、正の第１レンズ、物体側の面が凹形状となっている第２レンズ及び負の第３レンズからなる３枚構成撮像系を開示している。この３枚構成撮像系は、小型で像面湾曲も小さい。しかし、この３枚構成撮像系のエフ・ナンバーは３．５であり、一般的に使用されているエフ・ナンバー２．８の撮像光学系と比較すると、中心付近のコントラストが低下し画質が低下する。 Patent Document 1 discloses a three-element imaging system including, in order from the object side, a positive first lens, a second lens having a concave surface on the object side, and a negative third lens. This three-element imaging system is small and has a small field curvature. However, the F number of this three-element imaging system is 3.5, and compared with the imaging optical system of F number 2.8 that is generally used, the contrast near the center is lowered and the image quality is lowered. To do.
　特許文献２は、物体側から順に正の第１レンズ、物体側に凹面を向けた正または負の第２レンズ及び正または負の第３レンズからなる３枚構成撮像系を開示している。この３枚構成撮像系は、小型でエフ・ナンバーが３．０以下のものも含む。しかし、しかし、この３枚構成撮像系の球面収差は比較的大きく、球面収差の劣化により画質が低下する。 Patent Document 2 discloses a three-element imaging system including a positive first lens in order from the object side, a positive or negative second lens having a concave surface facing the object side, and a positive or negative third lens. This three-lens imaging system includes a small one having an F number of 3.0 or less. However, the spherical aberration of this three-element imaging system is relatively large, and the image quality deteriorates due to the deterioration of the spherical aberration.
　このように、収差、周辺光量比、明るさなどで４枚構成の撮像光学系と同等以上の高い光学性能を備えた３枚構成の撮像光学系は開発されていない。 Thus, a three-lens imaging optical system having high optical performance equivalent to or higher than that of a four-lens imaging optical system in terms of aberration, peripheral light amount ratio, brightness, etc. has not been developed.
　特許文献１　特開２００８－２７６２００号公報
　特許文献２　特開２００７－２６４１８１号公報 Patent Document 1 Japanese Unexamined Patent Application Publication No. 2008-276200 Patent Document 2 Japanese Unexamined Patent Application Publication No. 2007-264181
　したがって、収差、周辺光量比、明るさなどで４枚構成の撮像光学系と同等以上の高い光学性能を備えた３枚構成の撮像光学系に対するニーズがある。 Accordingly, there is a need for a three-lens imaging optical system having high optical performance equivalent to or higher than that of a four-lens imaging optical system in terms of aberration, peripheral light amount ratio, brightness, and the like.
　本発明による撮像光学系は、物体側から像側に、像側に回折格子が付された正の第１レンズ、像側に凸面を向けたメニスカスレンズである第２レンズ、負のメニスカスレンズである第３レンズから構成され、絞りが第１レンズの像側の面よりも物体側に配置された撮像光学系であって、Ｄ１２は第１レンズ及び第２レンズ間の光軸上の距離、ＴＴＬは第１レンズの物体側の頂点から像面までの距離、φ１は、第１レンズのパワー、φ２は、第２レンズのパワー、φは、第１レンズ、第２レンズ及び第３レンズの合成パワー、Ｆｎｏは光学系のエフ・ナンバー、ｒ１は、第１レンズの物体側の面の曲率半径であるとして、
　0.18<D12×φ<0.22　　　　(1)
　1.1<TTL×φ<1.22　　  　 (2)
　Fno<3.0　　　　　　　　　(3)
　0.46<r1×φ<0.49　　　　 (4)
　0.8<φ/φ1<1.0　　　　   (5)
　|φ2/φ|<0.1　　　　　　 (6)
を満足する。 The imaging optical system according to the present invention includes a positive first lens having a diffraction grating on the image side from the object side to the image side, a second lens that is a meniscus lens having a convex surface facing the image side, and a negative meniscus lens. An imaging optical system that includes a third lens and whose diaphragm is disposed on the object side of the image side surface of the first lens, D12 is a distance on the optical axis between the first lens and the second lens, TTL is the distance from the object-side vertex of the first lens to the image plane, φ1 is the power of the first lens, φ2 is the power of the second lens, and φ is the power of the first lens, the second lens, and the third lens. The combined power, Fno is the F number of the optical system, and r1 is the radius of curvature of the object side surface of the first lens.
0.18 <D12 × φ <0.22 (1)
1.1 <TTL × φ <1.22 (2)
Fno <3.0 (3)
0.46 <r1 × φ <0.49 (4)
0.8 <φ / φ1 <1.0 (5)
| φ2 / φ | <0.1 (6)
Satisfied.
　本発明による撮像光学系において、第１レンズを正のレンズとすることによって光学系を小型化しやすくなる。第１レンズの像側に回折格子を付することによって、軸上の色収差が改善され、高解像度を実現することが可能となる。第２レンズを像側に凸面を向けたメニスカスレンズとすることによって、像面湾曲を低減させることができる。第３レンズを負のレンズとすることにより、射出瞳位置を物体側に持っていくことができ、バックフォーカスを維持しながら画像素子の周縁部への入射角度を低減することができる。また、　絞りを第１レンズの像側の面より物体側に配置することにより、光学系を小型化することができる。さらに、式（１）乃至（６）を満たすことにより、小型でありながら、製造しやすく、像面湾曲が小さく、明るい、高画質の画像を生成する光学系が得られる。 In the imaging optical system according to the present invention, it is easy to reduce the size of the optical system by using the first lens as a positive lens. By attaching a diffraction grating to the image side of the first lens, axial chromatic aberration is improved and high resolution can be realized. By making the second lens a meniscus lens having a convex surface facing the image side, field curvature can be reduced. By making the third lens a negative lens, the exit pupil position can be brought to the object side, and the incident angle to the peripheral edge of the image element can be reduced while maintaining the back focus. Also, the optical system can be miniaturized by disposing the stop closer to the object side than the image side surface of the first lens. Furthermore, by satisfying the formulas (1) to (6), an optical system that is small and easy to manufacture, has a small curvature of field, and generates a bright, high-quality image can be obtained.
　本発明の実施形態による撮像光学系において、第２レンズは、近軸領域から周辺に向かって像側の面の負のパワーが強くなる、パワー０のメニスカスレンズである。 In the imaging optical system according to the embodiment of the present invention, the second lens is a zero-power meniscus lens in which the negative power of the image side surface increases from the paraxial region toward the periphery.
　本実施形態において、第２レンズは、近軸領域から周辺に向かって像側の面の負のパワーが強くなるので、周辺光線の周辺の光線高さを維持したまま、中心光線の周辺の光線高さを小さくすることができるので周辺光量比を大きくすることができる。また、第２レンズのパワーを０とすることにより、組み立ての際の、第１レンズに対する第２レンズの偏芯感度を低減することが可能となり、製造コストを低減することができる。また、高分散の材料を使用しても軸上色収差を変化させることがなく、周辺の色倍率収差を改善することができる。 In the present embodiment, since the negative power of the image side surface of the second lens increases from the paraxial region toward the periphery, the light beam around the central light beam is maintained while maintaining the light beam height around the peripheral light beam. Since the height can be reduced, the peripheral light quantity ratio can be increased. Further, by setting the power of the second lens to 0, it is possible to reduce the eccentric sensitivity of the second lens with respect to the first lens during assembly, and it is possible to reduce the manufacturing cost. Further, even if a highly dispersed material is used, axial chromatic aberration is not changed, and peripheral chromatic aberration can be improved.
　本発明の実施形態による撮像光学系において、第１レンズが近軸領域において、凸平または両凸レンズである。 In the imaging optical system according to the embodiment of the present invention, the first lens is a convex flat or biconvex lens in the paraxial region.
　第１レンズの像面側を凹面にしないことにより、レンズのコバ部分に迷光が導入されにくくなり、コバ部分の内部反射を経て撮像素子の像面に入射する迷光を削減することができる。この結果、画質を向上させることができる。 By not making the image surface side of the first lens concave, stray light is less likely to be introduced into the edge portion of the lens, and stray light incident on the image surface of the image sensor through internal reflection of the edge portion can be reduced. As a result, the image quality can be improved.
　本発明の実施形態による撮像光学系において、第３レンズの物体側の面は、近軸領域及び周辺領域において正のパワーを有し、該近軸領域と該周辺領域の中間領域で負のパワーを有する。 In the imaging optical system according to the embodiment of the present invention, the object side surface of the third lens has positive power in the paraxial region and the peripheral region, and negative power in the intermediate region between the paraxial region and the peripheral region. Have
　第３レンズの物体側の面が、近軸領域及び周辺領域において正のパワーを有し、該近軸領域と該周辺領域の中間領域で負のパワーを有するように形成することによって、像面湾曲を天元させながら、周辺光線の中心光線の光線高さを大きくすることができるので、撮像素子の周縁部への光線の入射角度を低減させることができる。 By forming the object side surface of the third lens so as to have a positive power in the paraxial region and the peripheral region, and to have a negative power in the intermediate region between the paraxial region and the peripheral region, the image plane Since the height of the central ray of the peripheral rays can be increased while the curvature is reduced, the incident angle of the rays on the peripheral edge of the image sensor can be reduced.
　本発明の実施形態による撮像光学系において、第３レンズの像側の面は、近軸領域において負のパワーを有し、周辺領域において正のパワーを有する。 In the imaging optical system according to the embodiment of the present invention, the image side surface of the third lens has negative power in the paraxial region and positive power in the peripheral region.
　第３レンズの像側の面が、近軸領域において負のパワーを有し、周辺領域において正のパワーを有するように形成し、第１乃至第３レンズの近軸領域を凸凸凹とし、第１乃至第３レンズの周辺領域を凸凹凸とすることによって、周辺光量比を大きくし、結像性能を向上させることができる。 The image side surface of the third lens is formed so as to have a negative power in the paraxial region and a positive power in the peripheral region, and the paraxial region of the first to third lenses is made uneven. By making the peripheral areas of the first to third lenses convex and concave, the peripheral light quantity ratio can be increased and the imaging performance can be improved.
　本発明の実施形態による撮像光学系において、φ３は、第３レンズのパワーであるとして、
　-3.3<φ/φ3<-2.6　　　　 (7)
を満足する。 In the imaging optical system according to the embodiment of the present invention, φ3 is the power of the third lens.
-3.3 <φ / φ3 <-2.6 (7)
Satisfied.
　φ/φ3が式（７）の下限値よりも小さくなると、撮像素子への入射角度が大きくなり、画質の低下を生じる。φ/φ3が式（７）の上限値よりも大きくなると、像面湾曲が劣化し、レンズの解像度が低下する。 When φ / φ3 is smaller than the lower limit value of the equation (7), the incident angle to the image sensor increases and the image quality is deteriorated. When φ / φ3 becomes larger than the upper limit value of the equation (7), the field curvature is deteriorated and the resolution of the lens is lowered.
　本発明の実施形態による撮像光学系において、ｖd1は第１レンズの材料のｄ線(波長587.6nm)でのアッべ数、ｖd3は第３レンズの材料のｄ線(波長587.6nm)でのアッべ数、 nd1は第１レンズの材料のｄ線(波長587.6nm)での屈性率、nd3は第三レンズの材料のｄ線(波長587.6nm)での屈折率であるとして、
　54<vd1,vd3<58　　　　 　　 (8)
　1.5<nd1,nd3<1.54　　　　　 (9)
を満足する。 In the imaging optical system according to the embodiment of the present invention, v d 1 is the Abbe number of the first lens material on the d-line (wavelength 587.6 nm), and v d 3 is the third lens material d-line (wavelength 587.6 nm). ), N d 1 is the refractive index of the first lens material at the d-line (wavelength 587.6 nm), and n d 3 is the refraction of the third lens material at the d-line (wavelength 587.6 nm). As a rate
54 <v d 1, v d 3 <58 (8)
1.5 <n d 1, n d 3 <1.54 (9)
Satisfied.
　第１レンズ及び第３レンズにオレフィン系などの樹脂材料を使用することができ、ガラスを使用する場合と比較してコストを低減することができる。 Resin materials such as olefins can be used for the first lens and the third lens, and the cost can be reduced compared to the case of using glass.
　本発明の実施形態による撮像光学系において、nd2は第２レンズの材料のｄ線(波長587.6nm)での屈折率、r3は第２レンズ物体側の曲率半径、r4は第２レンズの像側の曲率半径、D2は第２レンズの中心厚であるとして、
　　(nd2-1)×(1/r3-1/r4)+(nd2-1)2×D2/(nd2×r3×r4)=0　　 (10)
を満足する。 In the imaging optical system according to the embodiment of the present invention, n d 2 is the refractive index of the second lens material at the d-line (wavelength 587.6 nm), r 3 is the radius of curvature on the second lens object side, and r 4 is the second lens. The curvature radius on the image side, D2, is the center thickness of the second lens.
(n d 2-1) × (1 / r3-1 / r4) + (n d 2-1) 2 × D2 / (n d 2 × r3 × r4) = 0 (10)
Satisfied.
　式（１０）の左辺は第２レンズのパワーを表す。第２レンズの正または負のパワーの絶対値が大きくなるほど球面収差が大きくなる。第２レンズのパワーを０とすることにより、組み立ての際の、第１レンズに対する第２レンズの偏芯感度を低減することが可能となり、製造コストを低減することができる。また、高分散の材料を使用しても軸上色収差を変化させることがなく、周辺の色倍率収差を改善することができる。 The left side of Equation (10) represents the power of the second lens. As the absolute value of the positive or negative power of the second lens increases, the spherical aberration increases. By setting the power of the second lens to 0, it is possible to reduce the eccentricity sensitivity of the second lens with respect to the first lens during assembly, thereby reducing the manufacturing cost. Further, even if a highly dispersed material is used, axial chromatic aberration is not changed, and peripheral chromatic aberration can be improved.
　本発明の実施形態による撮像光学系において、φDOEは第１レンズの回折格子のパワーであるとして、
　0.05<φDOE/φ<0.07　　 (11)
を満足する。 In the imaging optical system according to the embodiment of the present invention, φDOE is the power of the diffraction grating of the first lens.
0.05 <φDOE / φ <0.07 (11)
Satisfied.
　φDOE/φが式（７）の上限値より大きいと、回折格子の作用によるゴースト・フレアの影響が大きくなる。φDOE/φが式（７）の下限値より小さいと、回折格子による色消し効果が弱くレンズの解像度を向上させることができない。 If φDOE / φ is larger than the upper limit of equation (7), the influence of ghost and flare due to the action of the diffraction grating becomes large. If φDOE / φ is smaller than the lower limit of equation (7), the achromatic effect by the diffraction grating is weak and the resolution of the lens cannot be improved.
　本発明の実施形態による撮像光学系において、
　0.27<Fno<3.0　　　　　 (12)
を満足する。 In the imaging optical system according to the embodiment of the present invention,
0.27 <Fno <3.0 (12)
Satisfied.
　エフ・ナンバーが式（１２）の下限値よりも小さいと、焦点深度が浅くなり、組み立ての際の偏芯感度が大きくなり、製造コストが上昇する。エフ・ナンバーが式（１２）の上限値よりも大きいと、回折限界により解像度の劣化を生じる。 When the F number is smaller than the lower limit value of the equation (12), the depth of focus becomes shallow, the eccentricity sensitivity at the time of assembly increases, and the manufacturing cost increases. When the F number is larger than the upper limit value of the equation (12), the resolution is deteriorated due to the diffraction limit.
実施例１による撮像光学系の構成を示す図である。1 is a diagram illustrating a configuration of an imaging optical system according to Example 1. FIG. 実施例１による撮像光学系の収差を示す図である。FIG. 6 is a diagram illustrating aberrations of the imaging optical system according to Example 1. 実施例２による撮像光学系の構成を示す図である。FIG. 6 is a diagram illustrating a configuration of an imaging optical system according to a second embodiment. 実施例２による撮像光学系の収差を示す図である。FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 2. 実施例３による撮像光学系の構成を示す図である。6 is a diagram illustrating a configuration of an imaging optical system according to Example 3. FIG. 実施例３による撮像光学系の収差を示す図である。FIG. 6 is a diagram illustrating aberrations of the imaging optical system according to Example 3. 実施例４による撮像光学系の構成を示す図である。FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 4. 実施例４による撮像光学系の収差を示す図である。FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 4. 実施例５による撮像光学系の構成を示す図である。FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 5. 実施例５による撮像光学系の構成を示す図である。FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 5. 実施例６による撮像光学系の構成を示す図である。FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 6. 実施例６による撮像光学系の収差を示す図である。FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 6. 実施例７による撮像光学系の構成を示す図である。FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 7. 実施例７による撮像光学系の収差を示す図である。FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 7. 実施例８による撮像光学系の構成を示す図である。FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 8. 実施例８による撮像光学系の収差を示す図である。FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 8. 実施例９による撮像光学系の構成を示す図である。FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 9. 実施例９による撮像光学系の収差を示す図である。FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 9. 実施例１０による撮像光学系の構成を示す図である。FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 10. 実施例１０による撮像光学系の収差を示す図である。FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 10. 実施例１１による撮像光学系の構成を示す図である。FIG. 10 is a diagram illustrating a configuration of an imaging optical system according to Example 11. 実施例１１による撮像光学系の収差を示す図である。FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to Example 11. 実施例１２による撮像光学系の構成を示す図である。FIG. 16 is a diagram illustrating a configuration of an imaging optical system according to Example 12. 実施例１２による撮像光学系の収差を示す図である。FIG. 14 shows aberrations of the image pickup optical system according to the twelfth embodiment. 実施例１３による撮像光学系の構成を示す図である。FIG. 16 is a diagram illustrating a configuration of an imaging optical system according to Example 13. 実施例１３による撮像光学系の収差を示す図である。It is a figure which shows the aberration of the imaging optical system by Example 13. 実施例１４による撮像光学系の構成を示す図である。FIG. 16 is a diagram illustrating a configuration of an imaging optical system according to Example 14. 実施例１４による撮像光学系の収差を示す図である。It is a figure which shows the aberration of the imaging optical system by Example 14. 実施例１５による撮像光学系の構成を示す図である。FIG. 16 is a diagram illustrating a configuration of an imaging optical system according to Example 15. 実施例１５による撮像光学系の収差を示す図である。FIG. 20 is a diagram illustrating aberrations of the image pickup optical system according to the fifteenth embodiment.
　図１は、本発明の一実施形態による撮像光学系の構成を示す図である。本実施形態による撮像光学系は、物体側から像側に、第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を通過した光は、ガラス板Ｅ４を通過して像面ＩＳに至る。 FIG. 1 is a diagram showing a configuration of an imaging optical system according to an embodiment of the present invention. In the imaging optical system according to the present embodiment, light that has passed through the first lens E1, the second lens E2, and the third lens E3 from the object side to the image side passes through the glass plate E4 and reaches the image plane IS.
　以下において、本発明による撮像光学系の特徴について説明する。 Hereinafter, features of the imaging optical system according to the present invention will be described.
３枚レンズの種類
　本発明の実施形態による撮像光学系は、物体側から像側に、像側に回折格子が付された正のレンズである第１レンズ、像側に凸面を向けたメニスカスレンズである第２レンズ及び負のメニスカスレンズである第３レンズを備える。絞りは、第１レンズの像側の面よりも物体側に配置されている。 Types of Three Lenses An imaging optical system according to an embodiment of the present invention includes a first lens that is a positive lens having a diffraction grating on the image side from the object side to the image side, and a meniscus lens having a convex surface on the image side. And a third lens which is a negative meniscus lens. The stop is disposed closer to the object side than the image side surface of the first lens.
　第１レンズを正のレンズとすることによって光学系を小型化しやすくなる。 ¡By making the first lens a positive lens, it becomes easy to miniaturize the optical system.
　第１レンズの像側に回折格子を付することによって、軸上の色収差が改善され、高解像度を実現することが可能となる。 By attaching a diffraction grating to the image side of the first lens, axial chromatic aberration is improved and high resolution can be realized.
　第２レンズを像側に凸面を向けたメニスカスレンズとすることによって、像面湾曲を低減させることができる。 By using the second lens as a meniscus lens having a convex surface facing the image side, curvature of field can be reduced.
　第３レンズを負のレンズとすることにより、射出瞳位置を物体側に持っていくことができ、バックフォーカスを維持しながら画像素子の周縁部への入射角度を低減することができる。 When the third lens is a negative lens, the exit pupil position can be brought to the object side, and the incident angle to the peripheral edge of the image element can be reduced while maintaining the back focus.
絞りの位置
　絞りを第１レンズの像側の面より物体側に配置することにより、光学系を小型化することができる。 The optical system can be miniaturized by disposing the aperture stop on the object side with respect to the image side surface of the first lens.
第１及び第２レンズ間の光軸上の距離D12と３枚のレンズの合成パワーφとの積
本発明の実施形態による光学系は、
　0.18<D12×φ<0.22　　　　(1)
を満たすように構成される。D12×φが式（１）の下限値を下回ると、組み立ての際の、第２レンズの第１レンズに対する偏芯感度が増加し、製造コストが増加する。D12×φが式（１）の上限値を上回ると、光学系が大型化する。 The product of the distance D12 on the optical axis between the first and second lenses and the combined power φ of the three lenses is an optical system according to an embodiment of the present invention.
0.18 <D12 × φ <0.22 (1)
Configured to meet. When D12 × φ is lower than the lower limit value of the expression (1), the eccentricity sensitivity of the second lens with respect to the first lens during assembly increases, and the manufacturing cost increases. When D12 × φ exceeds the upper limit value of the formula (1), the optical system becomes large.
第１レンズの物体側の頂点から像面までの距離TTLと３枚のレンズの合成パワーφとの積
本発明の実施形態による光学系は、
　　1.1<TTL×φ<1.22　　　 (2)
を満たすように構成される。TTL×φが式（２）の下限値を下回ると、光学系の像面湾曲による解像度の劣化が大きくなる。TTL×φが式式（２）の上限値を上回ると、光学系が大型化する。なお、本明細書においてレンズのパワーとは、近軸付近のレンズのパワーを意味する。 The product of the distance TTL from the object-side vertex of the first lens to the image plane and the combined power φ of the three lenses is an optical system according to an embodiment of the present invention.
1.1 <TTL × φ <1.22 (2)
Configured to meet. When TTL × φ is lower than the lower limit value of the expression (2), resolution degradation due to curvature of field of the optical system increases. If TTL × φ exceeds the upper limit value of the formula (2), the optical system becomes large. In this specification, the lens power means the power of the lens near the paraxial axis.
エフ・ナンバーFno
本発明の実施形態による光学系は、
　Fno<3.0　　　　　　　　　(3)
を満たすように構成される。Fnoが３より大きくなると、回折限界により解像度の劣化が生じる。 F number Fno
An optical system according to an embodiment of the present invention includes:
Fno <3.0 (3)
Configured to meet. When Fno is larger than 3, resolution is degraded due to the diffraction limit.
第１レンズの物体側の面の曲率半径r1と３枚のレンズの合成パワーφとの積
本発明の実施形態による光学系は、
　0.46<r1×φ<0.49　　　　　(4)
を満たすように構成される。r1×φが式（４）の下限値を下回ると、球面収差が大きくなり、解像度の劣化が生じる。また、球面収差を小さくするために、エフ・ナンバーを大きくして明るさを減少させるとコントラストの低下を生じる。このように、いずれにしても、画質が低下する。r1×φが式（４）の上限値を上回ると、光学系が大型化する。 The product of the radius of curvature r1 of the object side surface of the first lens and the combined power φ of the three lenses is an optical system according to an embodiment of the present invention.
0.46 <r1 × φ <0.49 (4)
Configured to meet. When r1 × φ is less than the lower limit value of the equation (4), spherical aberration increases and resolution is degraded. Further, when the F number is increased to reduce the brightness in order to reduce the spherical aberration, the contrast is lowered. Thus, in any case, the image quality is degraded. If r1 × φ exceeds the upper limit value of the equation (4), the optical system becomes large.
３枚のレンズの合成パワーφと第１レンズのパワーφ1との比
本発明の実施形態による光学系は、
　　0.8<φ/φ1<1.0　　　　 (5)
を満たすように構成される。φ/φ1が式（５）の下限値を下回ると、組み立ての際の、第２レンズの第１レンズに対する偏芯感度が増加し、製造コストが増加する。φ/φ1が式（５）の上限値を上回ると、光学系が大型化する。 Ratio of combined power [phi] of the three lenses and power [phi] 1 of the first lens The optical system according to the embodiment of the present invention is
0.8 <φ / φ1 <1.0 (5)
Configured to meet. If φ / φ1 is below the lower limit of the equation (5), the eccentricity sensitivity of the second lens to the first lens during assembly increases, and the manufacturing cost increases. When φ / φ1 exceeds the upper limit value of the equation (5), the optical system becomes large.
第２レンズのパワーφ2と３枚のレンズの合成パワーφとの比の絶対値
本発明の実施形態による光学系は、
　|φ2/φ|<0.1　　　　　　 (6)
を満たすように構成される。|φ2/φ|が式（６）の上限値を上回ると、組み立ての際の、第２レンズの第１レンズに対する偏芯感度が増加し、製造コストが増加する。 The absolute value of the ratio of the power [phi] 2 of the second lens and the combined power [phi] of the three lenses is the optical system according to the embodiment of the present invention.
| φ2 / φ | <0.1 (6)
Configured to meet. If | φ2 / φ | exceeds the upper limit value of Expression (6), the eccentricity sensitivity of the second lens to the first lens during assembly increases, and the manufacturing cost increases.
レンズの材料
　本発明の実施形態による撮像光学系は、レンズが全てプラスチック（樹脂）材料で形成されている。したがって、レンズをすべてモールド成形で製作でき、量産に適している。一例として、第１及び第３レンズの材料は、シクロオレフィンポリマー(COP)樹脂）であり、第２レンズの材料は、シクロオレフィンポリマー(COP)樹脂またはポリカーボネード(PC)樹脂またはシクロオレフィンコポリマー(COC)樹脂である。 Lens Material In the imaging optical system according to the embodiment of the present invention, the lenses are all formed of a plastic (resin) material. Therefore, all the lenses can be manufactured by molding, which is suitable for mass production. As an example, the material of the first and third lenses is a cycloolefin polymer (COP) resin, and the material of the second lens is a cycloolefin polymer (COP) resin or a polycarbonate (PC) resin or a cycloolefin copolymer (COC). ) Resin.
実施例による撮像光学系の仕様
　表１及び表２は、実施例１乃至１５の撮像光学系の仕様を表す表である。表１及び表２において長さの単位はミリメータである。
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
 Specifications Table 1 and Table 2 of the imaging optical system according to the examples are tables showing the specifications of the imaging optical systems of Examples 1 to 15. In Tables 1 and 2, the unit of length is millimeter.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
実施例１
　図１は、実施例１による撮像光学系の構成を示す図である。本実施形態による撮像光学系は、物体側から像側に、第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を備える。第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を通過した光は、ガラス板Ｅ４を通過して像面ＩＳに至る。 Example 1
FIG. 1 is a diagram illustrating a configuration of an imaging optical system according to the first embodiment. The imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side. The light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
　図２は、実施例１による撮像光学系の収差を示す図である。図２（ａ）は、軸上色収差を示す図である。図２（ａ）の横軸は、光軸方向の焦点位置（単位はミリメータ）を示す。図２（ａ）の縦軸は、光線の絞りにおける通過位置を示す。縦軸の０は、光線が絞りの中心を通過することを示し、縦軸の１は、光線が絞りの端を通過することを示す。図２（ｂ）は、非点収差および像面湾曲を示す図である。図２（ｂ）の横軸は、光軸方向の焦点位置を示す（単位はミリメータ）。図２（ｂ）の縦軸は、像高さ（単位はミリメータ）を示す。点線は子午像面の位置を表し、実線は球欠像面の位置を表す。図２（ｃ）は、歪曲収差を示す図である。図２（ｃ）の横軸は、歪曲収差（ディストーション）を示す。図２（ｃ）の縦軸は、像高さ（単位はミリメータ）を示す。 FIG. 2 is a diagram illustrating aberrations of the image pickup optical system according to the first embodiment. FIG. 2A is a diagram showing axial chromatic aberration. The horizontal axis of Fig.2 (a) shows the focus position (a unit is a millimeter) of an optical axis direction. The vertical axis | shaft of Fig.2 (a) shows the passage position in the aperture_diaphragm | restriction of a light ray. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop. FIG. 2B is a diagram showing astigmatism and field curvature. The horizontal axis of FIG.2 (b) shows the focus position of an optical axis direction (a unit is a millimeter). The vertical axis | shaft of FIG.2 (b) shows image height (a unit is a millimeter). The dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane. FIG. 2C is a diagram showing distortion. The horizontal axis of FIG.2 (c) shows a distortion aberration (distortion). The vertical axis | shaft of FIG.2 (c) shows image height (a unit is a millimeter).
　表３は、実施例１による撮像光学系のレンズデータを示す表である。表３において、絞りの面間隔は、絞りの位置を基準とし、像側をプラスとした場合の第２面の位置である。その他の面について、例として、第２面（第１レンズの物体側の面）の面間隔は、第２面と第３面（第２レンズの像側の面）との間隔である。 Table 3 is a table showing lens data of the imaging optical system according to Example 1. In Table 3, the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive. For other surfaces, as an example, the surface interval of the second surface (the object side surface of the first lens) is the interval between the second surface and the third surface (the image side surface of the second lens).
　表４は、第２面乃至第７面の非球面形状を表す式の係数および定数を示す表である。撮像光学系の光軸をｚ軸とし、光軸に垂直な面の座標をｘ、ｙとする直交座標系において、非球面形状は、以下の式で表される２次曲線を、光軸、すなわちｚ軸の周りに回転させた光軸対称回転面である。ただし、ｋは２次曲線の形状を定める定数、ｃは中心曲率である。また、Ａｉは補正係数である。なお、表４における第２面のＲが、ｒ１に相当する。 Table 4 is a table showing coefficients and constants of expressions representing the aspheric shapes of the second surface to the seventh surface. In an orthogonal coordinate system in which the optical axis of the imaging optical system is the z-axis and the coordinates of the plane perpendicular to the optical axis are x and y, the aspherical shape is a quadratic curve represented by the following formula: That is, it is an optical axis symmetric rotation surface rotated about the z axis. Here, k is a constant that determines the shape of the quadratic curve, and c is the central curvature. A i is a correction coefficient. In Table 4, R on the second surface corresponds to r1.
　表４以下の表において、Ａが実数、Ｎが整数であるとして、Ａ１０Ｅ－Ｎは、
　Ａ・１０－Ｎ
を表す。
Figure JPOXMLDOC01-appb-M000001
 In the tables below, assuming that A is a real number and N is an integer, A10E-N is
A ・ 10 －N
Represents.
Figure JPOXMLDOC01-appb-M000001
　表５は、回折格子の光路差関数の係数を示す表である。光路差関数は、以下の式で定義される。光路差関数は、５５０ｎｍの規格化波長の１次光で定義されている。
φ=C2×ｈ２+C4×h4+C6×h6+C8×h8+C10×h10 Table 5 is a table showing coefficients of the optical path difference function of the diffraction grating. The optical path difference function is defined by the following equation. The optical path difference function is defined by primary light having a normalized wavelength of 550 nm.
φ = C2 × h 2 + C4 × h 4 + C6 × h 6 + C8 × h 8 + C10 × h 10
　非球面形状の式及び光路差関数の式は、以下の実施例においても同様である。
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
 The formula for the aspheric shape and the formula for the optical path difference function are the same in the following embodiments.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
実施例２
　図３は、実施例２による撮像光学系の構成を示す図である。本実施形態による撮像光学系は、物体側から像側に、第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を備える。第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を通過した光は、ガラス板Ｅ４を通過して像面ＩＳに至る。 Example 2
FIG. 3 is a diagram illustrating a configuration of the imaging optical system according to the second embodiment. The imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side. The light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
　図４は、実施例２による撮像光学系の収差を示す図である。図４（ａ）は、軸上色収差を示す図である。図４（ａ）の横軸は、光軸方向の焦点位置（単位はミリメータ）を示す。図４（ａ）の縦軸は、光線の絞りにおける通過位置を示す。縦軸の０は、光線が絞りの中心を通過することを示し、縦軸の１は、光線が絞りの端を通過することを示す。図４（ｂ）は、非点収差および像面湾曲を示す図である。図４（ｂ）の横軸は、光軸方向の焦点位置を示す（単位はミリメータ）。図４（ｂ）の縦軸は、像高さ（単位はミリメータ）を示す。点線は子午像面の位置を表し、実線は球欠像面の位置を表す。図４（ｃ）は、歪曲収差を示す図である。図４（ｃ）の横軸は、歪曲収差（ディストーション）を示す。図４（ｃ）の縦軸は、像高さ（単位はミリメータ）を示す。 FIG. 4 is a diagram illustrating aberrations of the imaging optical system according to the second embodiment. FIG. 4A is a diagram showing axial chromatic aberration. The horizontal axis of Fig.4 (a) shows the focus position (a unit is a millimeter) of an optical axis direction. The vertical axis in FIG. 4A indicates the passing position in the aperture of the light beam. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop. FIG. 4B is a diagram showing astigmatism and field curvature. The horizontal axis of FIG.4 (b) shows the focus position of an optical axis direction (a unit is a millimeter). The vertical axis | shaft of FIG.4 (b) shows image height (a unit is a millimeter). The dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane. FIG. 4C is a diagram showing distortion. The horizontal axis of FIG.4 (c) shows a distortion aberration (distortion). The vertical axis | shaft of FIG.4 (c) shows image height (a unit is a millimeter).
　表６は、実施例２による撮像光学系のレンズデータを示す表である。表６において、絞りの面間隔は、絞りの位置を基準とし、像側をプラスとした場合の第２面の位置である。その他の面について、例として、第２面（第１レンズの物体側の面）の面間隔は、第２面と第３面（第２レンズの像側の面）との間隔である。 Table 6 is a table showing lens data of the imaging optical system according to Example 2. In Table 6, the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive. For other surfaces, as an example, the surface interval of the second surface (the object side surface of the first lens) is the interval between the second surface and the third surface (the image side surface of the second lens).
　表７は、第２面乃至第７面の非球面形状を表す式の係数および定数を示す表である。 Table 7 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
　表８は、回折格子の光路差関数の係数を示す表である。
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000008
 Table 8 is a table showing coefficients of the optical path difference function of the diffraction grating.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000008
実施例３
　図５は、実施例３による撮像光学系の構成を示す図である。本実施形態による撮像光学系は、物体側から像側に、第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を備える。第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を通過した光は、ガラス板Ｅ４を通過して像面ＩＳに至る。 Example 3
FIG. 5 is a diagram illustrating a configuration of an imaging optical system according to the third embodiment. The imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side. The light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
　図６は、実施例３による撮像光学系の収差を示す図である。図６（ａ）は、軸上色収差を示す図である。図６（ａ）の横軸は、光軸方向の焦点位置（単位はミリメータ）を示す。図６（ａ）の縦軸は、光線の絞りにおける通過位置を示す。縦軸の０は、光線が絞りの中心を通過することを示し、縦軸の１は、光線が絞りの端を通過することを示す。図６（ｂ）は、非点収差および像面湾曲を示す図である。図６（ｂ）の横軸は、光軸方向の焦点位置を示す（単位はミリメータ）。図６（ｂ）の縦軸は、像高さ（単位はミリメータ）を示す。点線は子午像面の位置を表し、実線は球欠像面の位置を表す。図６（ｃ）は、歪曲収差を示す図である。図６（ｃ）の横軸は、歪曲収差（ディストーション）を示す。図６（ｃ）の縦軸は、像高さ（単位はミリメータ）を示す。 FIG. 6 is a diagram illustrating aberrations of the image pickup optical system according to the third embodiment. FIG. 6A is a diagram showing axial chromatic aberration. The horizontal axis of Fig.6 (a) shows the focus position (a unit is a millimeter) of an optical axis direction. The vertical axis | shaft of Fig.6 (a) shows the passage position in the aperture_diaphragm | restriction of a light ray. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop. FIG. 6B is a diagram showing astigmatism and field curvature. The horizontal axis of FIG.6 (b) shows the focus position of an optical axis direction (a unit is a millimeter). The vertical axis | shaft of FIG.6 (b) shows image height (a unit is a millimeter). The dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane. FIG. 6C is a diagram showing distortion. The horizontal axis of FIG.6 (c) shows a distortion aberration (distortion). The vertical axis | shaft of FIG.6 (c) shows image height (a unit is a millimeter).
　表９は、実施例３による撮像光学系のレンズデータを示す表である。表９において、絞りの面間隔は、絞りの位置を基準とし、像側をプラスとした場合の第２面の位置である。その他の面について、例として、第２面（第１レンズの物体側の面）の面間隔は、第２面と第３面（第２レンズの像側の面）との間隔である。 Table 9 is a table showing lens data of the imaging optical system according to Example 3. In Table 9, the diaphragm surface interval is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive. For other surfaces, as an example, the surface interval of the second surface (the object side surface of the first lens) is the interval between the second surface and the third surface (the image side surface of the second lens).
　表１０は、第２面乃至第７面の非球面形状を表す式の係数および定数を示す表である。 Table 10 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
　表１１は、回折格子の光路差関数の係数を示す表である。
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000011
 Table 11 is a table showing the coefficients of the optical path difference function of the diffraction grating.
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000011
実施例４
　図７は、実施例４による撮像光学系の構成を示す図である。本実施形態による撮像光学系は、物体側から像側に、第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を備える。第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を通過した光は、ガラス板Ｅ４を通過して像面ＩＳに至る。 Example 4
FIG. 7 is a diagram illustrating a configuration of an imaging optical system according to the fourth embodiment. The imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side. The light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
　図８は、実施例４による撮像光学系の収差を示す図である。図８（ａ）は、軸上色収差を示す図である。図８（ａ）の横軸は、光軸方向の焦点位置（単位はミリメータ）を示す。図８（ａ）の縦軸は、光線の絞りにおける通過位置を示す。縦軸の０は、光線が絞りの中心を通過することを示し、縦軸の１は、光線が絞りの端を通過することを示す。図８（ｂ）は、非点収差および像面湾曲を示す図である。図８（ｂ）の横軸は、光軸方向の焦点位置を示す（単位はミリメータ）。図８（ｂ）の縦軸は、像高さ（単位はミリメータ）を示す。点線は子午像面の位置を表し、実線は球欠像面の位置を表す。図８（ｃ）は、歪曲収差を示す図である。図８（ｃ）の横軸は、歪曲収差（ディストーション）を示す。図８（ｃ）の縦軸は、像高さ（単位はミリメータ）を示す。 FIG. 8 is a diagram illustrating aberrations of the imaging optical system according to the fourth example. FIG. 8A is a diagram showing axial chromatic aberration. The horizontal axis of Fig.8 (a) shows the focus position (a unit is a millimeter) of an optical axis direction. The vertical axis | shaft of Fig.8 (a) shows the passage position in the aperture_diaphragm | restriction of a light ray. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop. FIG. 8B is a diagram showing astigmatism and field curvature. The horizontal axis of FIG.8 (b) shows the focus position of an optical axis direction (a unit is a millimeter). The vertical axis | shaft of FIG.8 (b) shows image height (a unit is a millimeter). The dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane. FIG. 8C is a diagram showing distortion. The horizontal axis of FIG.8 (c) shows a distortion aberration (distortion). The vertical axis | shaft of FIG.8 (c) shows image height (a unit is a millimeter).
　表１２は、実施例４による撮像光学系のレンズデータを示す表である。表１２において、絞りの面間隔は、絞りの位置を基準とし、像側をプラスとした場合の第２面の位置である。その他の面について、例として、第２面（第１レンズの物体側の面）の面間隔は、第２面と第３面（第２レンズの像側の面）との間隔である。 Table 12 is a table showing lens data of the imaging optical system according to Example 4. In Table 12, the distance between the surfaces of the diaphragms is the position of the second surface when the position of the diaphragm is a reference and the image side is positive. For other surfaces, as an example, the surface interval of the second surface (the object side surface of the first lens) is the interval between the second surface and the third surface (the image side surface of the second lens).
　表１３は、第２面乃至第７面の非球面形状を表す式の係数および定数を示す表である。 Table 13 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
　表１４は、回折格子の光路差関数の係数を示す表である。
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000014
 Table 14 is a table | surface which shows the coefficient of the optical path difference function of a diffraction grating.
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000014
実施例５
　図９は、実施例５による撮像光学系の構成を示す図である。本実施形態による撮像光学系は、物体側から像側に、第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を備える。第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を通過した光は、ガラス板Ｅ４を通過して像面ＩＳに至る。 Example 5
FIG. 9 is a diagram illustrating the configuration of the imaging optical system according to the fifth embodiment. The imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side. The light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
　図１０は、実施例５による撮像光学系の収差を示す図である。図１０（ａ）は、軸上色収差を示す図である。図１０（ａ）の横軸は、光軸方向の焦点位置（単位はミリメータ）を示す。図１０（ａ）の縦軸は、光線の絞りにおける通過位置を示す。縦軸の０は、光線が絞りの中心を通過することを示し、縦軸の１は、光線が絞りの端を通過することを示す。図１０（ｂ）は、非点収差および像面湾曲を示す図である。図１０（ｂ）の横軸は、光軸方向の焦点位置を示す（単位はミリメータ）。図１０（ｂ）の縦軸は、像高さ（単位はミリメータ）を示す。点線は子午像面の位置を表し、実線は球欠像面の位置を表す。図１０（ｃ）は、歪曲収差を示す図である。図１０（ｃ）の横軸は、歪曲収差（ディストーション）を示す。図１０（ｃ）の縦軸は、像高さ（単位はミリメータ）を示す。 FIG. 10 is a diagram illustrating aberrations of the imaging optical system according to the fifth example. FIG. 10A is a diagram showing axial chromatic aberration. The horizontal axis of Fig.10 (a) shows the focus position (a unit is a millimeter) of an optical axis direction. The vertical axis | shaft of Fig.10 (a) shows the passage position in the aperture_diaphragm | restriction of a light ray. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop. FIG. 10B is a diagram showing astigmatism and curvature of field. The horizontal axis of FIG.10 (b) shows the focus position of an optical axis direction (a unit is a millimeter). The vertical axis | shaft of FIG.10 (b) shows image height (a unit is a millimeter). The dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane. FIG.10 (c) is a figure which shows a distortion aberration. The horizontal axis of FIG.10 (c) shows a distortion aberration (distortion). The vertical axis | shaft of FIG.10 (c) shows image height (a unit is a millimeter).
　表１５は、実施例５による撮像光学系のレンズデータを示す表である。表１５において、絞りの面間隔は、絞りの位置を基準とし、像側をプラスとした場合の第２面の位置である。その他の面について、例として、第２面（第１レンズの物体側の面）の面間隔は、第２面と第３面（第２レンズの像側の面）との間隔である。 Table 15 is a table showing lens data of the imaging optical system according to Example 5. In Table 15, the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive. For other surfaces, as an example, the surface interval of the second surface (the object side surface of the first lens) is the interval between the second surface and the third surface (the image side surface of the second lens).
　表１６は、第２面乃至第７面の非球面形状を表す式の係数および定数を示す表である。 Table 16 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
　表１７は、回折格子の光路差関数の係数を示す表である。
Figure JPOXMLDOC01-appb-T000015
Figure JPOXMLDOC01-appb-T000016
Figure JPOXMLDOC01-appb-T000017
 Table 17 is a table showing coefficients of the optical path difference function of the diffraction grating.
Figure JPOXMLDOC01-appb-T000015
Figure JPOXMLDOC01-appb-T000016
Figure JPOXMLDOC01-appb-T000017
実施例６
　図１１は、実施例６による撮像光学系の構成を示す図である。本実施形態による撮像光学系は、物体側から像側に、第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を備える。第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を通過した光は、ガラス板Ｅ４を通過して像面ＩＳに至る。 Example 6
FIG. 11 is a diagram illustrating a configuration of an imaging optical system according to the sixth embodiment. The imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side. The light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
　図１２は、実施例６による撮像光学系の収差を示す図である。図１２（ａ）は、軸上色収差を示す図である。図１２（ａ）の横軸は、光軸方向の焦点位置（単位はミリメータ）を示す。図１２（ａ）の縦軸は、光線の絞りにおける通過位置を示す。縦軸の０は、光線が絞りの中心を通過することを示し、縦軸の１は、光線が絞りの端を通過することを示す。図１２（ｂ）は、非点収差および像面湾曲を示す図である。図１２（ｂ）の横軸は、光軸方向の焦点位置を示す（単位はミリメータ）。図１２（ｂ）の縦軸は、像高さ（単位はミリメータ）を示す。点線は子午像面の位置を表し、実線は球欠像面の位置を表す。図１２（ｃ）は、歪曲収差を示す図である。図１２（ｃ）の横軸は、歪曲収差（ディストーション）を示す。図１２（ｃ）の縦軸は、像高さ（単位はミリメータ）を示す。 FIG. 12 is a diagram illustrating aberrations of the imaging optical system according to the sixth example. FIG. 12A is a diagram showing axial chromatic aberration. The horizontal axis of Fig.12 (a) shows the focus position (a unit is a millimeter) of an optical axis direction. The vertical axis | shaft of Fig.12 (a) shows the passage position in the aperture_diaphragm | restriction of a light ray. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop. FIG. 12B is a diagram showing astigmatism and curvature of field. The horizontal axis of FIG.12 (b) shows the focus position of an optical axis direction (a unit is a millimeter). The vertical axis | shaft of FIG.12 (b) shows image height (a unit is a millimeter). The dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane. FIG. 12C is a diagram showing distortion. The horizontal axis of FIG.12 (c) shows a distortion aberration (distortion). The vertical axis | shaft of FIG.12 (c) shows image height (a unit is a millimeter).
　表１８は、実施例６による撮像光学系のレンズデータを示す表である。表１８において、絞りの面間隔は、絞りの位置を基準とし、像側をプラスとした場合の第２面の位置である。その他の面について、例として、第２面（第１レンズの物体側の面）の面間隔は、第２面と第３面（第２レンズの像側の面）との間隔である。 Table 18 is a table showing lens data of the imaging optical system according to Example 6. In Table 18, the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive. For other surfaces, as an example, the surface interval of the second surface (the object side surface of the first lens) is the interval between the second surface and the third surface (the image side surface of the second lens).
　表１９は、第２面乃至第７面の非球面形状を表す式の係数および定数を示す表である。 Table 19 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
　表２０は、回折格子の光路差関数の係数を示す表である。
Figure JPOXMLDOC01-appb-T000018
Figure JPOXMLDOC01-appb-T000020
 Table 20 is a table | surface which shows the coefficient of the optical path difference function of a diffraction grating.
Figure JPOXMLDOC01-appb-T000018
Figure JPOXMLDOC01-appb-T000020
実施例７
　図１３は、実施例７による撮像光学系の構成を示す図である。本実施形態による撮像光学系は、物体側から像側に、第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を備える。第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を通過した光は、ガラス板Ｅ４を通過して像面ＩＳに至る。 Example 7
FIG. 13 is a diagram illustrating a configuration of an imaging optical system according to the seventh embodiment. The imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side. The light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
　図１４は、実施例７による撮像光学系の収差を示す図である。図１４（ａ）は、軸上色収差を示す図である。図１４（ａ）の横軸は、光軸方向の焦点位置（単位はミリメータ）を示す。図１４（ａ）の縦軸は、光線の絞りにおける通過位置を示す。縦軸の０は、光線が絞りの中心を通過することを示し、縦軸の１は、光線が絞りの端を通過することを示す。図１４（ｂ）は、非点収差および像面湾曲を示す図である。図１４（ｂ）の横軸は、光軸方向の焦点位置を示す（単位はミリメータ）。図１４（ｂ）の縦軸は、像高さ（単位はミリメータ）を示す。点線は子午像面の位置を表し、実線は球欠像面の位置を表す。図１４（ｃ）は、歪曲収差を示す図である。図１４（ｃ）の横軸は、歪曲収差（ディストーション）を示す。図１４（ｃ）の縦軸は、像高さ（単位はミリメータ）を示す。 FIG. 14 is a diagram illustrating aberrations of the image pickup optical system according to the seventh embodiment. FIG. 14A shows axial chromatic aberration. The horizontal axis of Fig.14 (a) shows the focus position (a unit is a millimeter) of an optical axis direction. The vertical axis | shaft of Fig.14 (a) shows the passage position in the aperture_diaphragm | restriction of a light ray. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop. FIG. 14B is a diagram showing astigmatism and curvature of field. The horizontal axis of FIG.14 (b) shows the focus position of an optical axis direction (a unit is a millimeter). The vertical axis | shaft of FIG.14 (b) shows image height (a unit is a millimeter). The dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane. FIG. 14C is a diagram showing distortion. The horizontal axis of FIG.14 (c) shows a distortion aberration (distortion). The vertical axis | shaft of FIG.14 (c) shows image height (a unit is a millimeter).
　表２１は、実施例７による撮像光学系のレンズデータを示す表である。表２１において、絞りの面間隔は、絞りの位置を基準とし、像側をプラスとした場合の第２面の位置である。その他の面について、例として、第２面（第１レンズの物体側の面）の面間隔は、第２面と第３面（第２レンズの像側の面）との間隔である。 Table 21 is a table showing lens data of the imaging optical system according to Example 7. In Table 21, the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive. For other surfaces, as an example, the surface interval of the second surface (the object side surface of the first lens) is the interval between the second surface and the third surface (the image side surface of the second lens).
　表２２は、第２面乃至第７面の非球面形状を表す式の係数および定数を示す表である。 Table 22 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
　表２３は、回折格子の光路差関数の係数を示す表である。
Figure JPOXMLDOC01-appb-T000021
Figure JPOXMLDOC01-appb-T000022
Figure JPOXMLDOC01-appb-T000023
 Table 23 is a table showing coefficients of the optical path difference function of the diffraction grating.
Figure JPOXMLDOC01-appb-T000021
Figure JPOXMLDOC01-appb-T000022
Figure JPOXMLDOC01-appb-T000023
実施例８
　図１５は、実施例８による撮像光学系の構成を示す図である。本実施形態による撮像光学系は、物体側から像側に、第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を備える。第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を通過した光は、ガラス板Ｅ４を通過して像面ＩＳに至る。 Example 8
FIG. 15 is a diagram illustrating a configuration of an imaging optical system according to the eighth embodiment. The imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side. The light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
　図１６は、実施例８による撮像光学系の収差を示す図である。図１６（ａ）は、軸上色収差を示す図である。図１６（ａ）の横軸は、光軸方向の焦点位置（単位はミリメータ）を示す。図１６（ａ）の縦軸は、光線の絞りにおける通過位置を示す。縦軸の０は、光線が絞りの中心を通過することを示し、縦軸の１は、光線が絞りの端を通過することを示す。図１６（ｂ）は、非点収差および像面湾曲を示す図である。図１６（ｂ）の横軸は、光軸方向の焦点位置を示す（単位はミリメータ）。図１６（ｂ）の縦軸は、像高さ（単位はミリメータ）を示す。点線は子午像面の位置を表し、実線は球欠像面の位置を表す。図１６（ｃ）は、歪曲収差を示す図である。図１６（ｃ）の横軸は、歪曲収差（ディストーション）を示す。図１６（ｃ）の縦軸は、像高さ（単位はミリメータ）を示す。 FIG. 16 is a diagram showing aberrations of the image pickup optical system according to the eighth embodiment. FIG. 16A is a diagram showing axial chromatic aberration. The horizontal axis of Fig.16 (a) shows the focus position (a unit is a millimeter) of an optical axis direction. The vertical axis | shaft of Fig.16 (a) shows the passage position in the aperture_diaphragm | restriction of a light ray. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop. FIG. 16B is a diagram showing astigmatism and field curvature. The horizontal axis in FIG. 16B indicates the focal position in the optical axis direction (unit: millimeter). The vertical axis | shaft of FIG.16 (b) shows image height (a unit is a millimeter). The dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane. FIG. 16C is a diagram illustrating distortion. The horizontal axis of FIG.16 (c) shows a distortion aberration (distortion). The vertical axis | shaft of FIG.16 (c) shows image height (a unit is a millimeter).
　表２４は、実施例８による撮像光学系のレンズデータを示す表である。表２４において、絞りの面間隔は、絞りの位置を基準とし、像側をプラスとした場合の第２面の位置である。その他の面について、例として、第２面（第１レンズの物体側の面）の面間隔は、第２面と第３面（第２レンズの像側の面）との間隔である。 Table 24 is a table showing lens data of the imaging optical system according to Example 8. In Table 24, the diaphragm surface interval is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive. For other surfaces, as an example, the surface interval of the second surface (the object side surface of the first lens) is the interval between the second surface and the third surface (the image side surface of the second lens).
　表２５は、第２面乃至第７面の非球面形状を表す式の係数および定数を示す表である。 Table 25 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
　表２６は、回折格子の光路差関数の係数を示す表である。
Figure JPOXMLDOC01-appb-T000024
Figure JPOXMLDOC01-appb-T000025
Figure JPOXMLDOC01-appb-T000026
 Table 26 is a table | surface which shows the coefficient of the optical path difference function of a diffraction grating.
Figure JPOXMLDOC01-appb-T000024
Figure JPOXMLDOC01-appb-T000025
Figure JPOXMLDOC01-appb-T000026
実施例９
　図１７は、実施例９による撮像光学系の構成を示す図である。本実施形態による撮像光学系は、物体側から像側に、第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を備える。第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を通過した光は、ガラス板Ｅ４を通過して像面ＩＳに至る。 Example 9
FIG. 17 is a diagram illustrating the configuration of the imaging optical system according to the ninth embodiment. The imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side. The light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
　図１８は、実施例９による撮像光学系の収差を示す図である。図１８（ａ）は、軸上色収差を示す図である。図１８（ａ）の横軸は、光軸方向の焦点位置（単位はミリメータ）を示す。図１８（ａ）の縦軸は、光線の絞りにおける通過位置を示す。縦軸の０は、光線が絞りの中心を通過することを示し、縦軸の１は、光線が絞りの端を通過することを示す。図１８（ｂ）は、非点収差および像面湾曲を示す図である。図１８（ｂ）の横軸は、光軸方向の焦点位置を示す（単位はミリメータ）。図１８（ｂ）の縦軸は、像高さ（単位はミリメータ）を示す。点線は子午像面の位置を表し、実線は球欠像面の位置を表す。図１８（ｃ）は、歪曲収差を示す図である。図１８（ｃ）の横軸は、歪曲収差（ディストーション）を示す。図１８（ｃ）の縦軸は、像高さ（単位はミリメータ）を示す。 FIG. 18 is a diagram illustrating aberrations of the imaging optical system according to the ninth example. FIG. 18A is a diagram showing axial chromatic aberration. The horizontal axis of Fig.18 (a) shows the focus position (a unit is a millimeter) of an optical axis direction. The vertical axis | shaft of Fig.18 (a) shows the passage position in the aperture_diaphragm | restriction of a light ray. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop. FIG. 18B is a diagram showing astigmatism and field curvature. The horizontal axis of FIG.18 (b) shows the focus position of an optical axis direction (a unit is a millimeter). The vertical axis | shaft of FIG.18 (b) shows image height (a unit is a millimeter). The dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane. FIG. 18C is a diagram showing distortion. The horizontal axis of FIG.18 (c) shows a distortion aberration (distortion). The vertical axis | shaft of FIG.18 (c) shows image height (a unit is a millimeter).
　表２７は、実施例９による撮像光学系のレンズデータを示す表である。表２７において、絞りの面間隔は、絞りの位置を基準とし、像側をプラスとした場合の第２面の位置である。その他の面について、例として、第２面（第１レンズの物体側の面）の面間隔は、第２面と第３面（第２レンズの像側の面）との間隔である。 Table 27 is a table showing lens data of the imaging optical system according to Example 9. In Table 27, the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive. For other surfaces, as an example, the surface interval of the second surface (the object side surface of the first lens) is the interval between the second surface and the third surface (the image side surface of the second lens).
　表２８は、第２面乃至第７面の非球面形状を表す式の係数および定数を示す表である。 Table 28 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
　表２９は、回折格子の光路差関数の係数を示す表である。
Figure JPOXMLDOC01-appb-T000027
Figure JPOXMLDOC01-appb-T000028
Figure JPOXMLDOC01-appb-T000029
 Table 29 is a table showing coefficients of the optical path difference function of the diffraction grating.
Figure JPOXMLDOC01-appb-T000027
Figure JPOXMLDOC01-appb-T000028
Figure JPOXMLDOC01-appb-T000029
実施例１０
　図１９は、実施例１０による撮像光学系の構成を示す図である。本実施形態による撮像光学系は、物体側から像側に、第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を備える。第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を通過した光は、ガラス板Ｅ４を通過して像面ＩＳに至る。 Example 10
FIG. 19 is a diagram illustrating the configuration of the imaging optical system according to the tenth embodiment. The imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side. The light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
　図２０は、実施例１０による撮像光学系の収差を示す図である。図２０（ａ）は、軸上色収差を示す図である。図２０（ａ）の横軸は、光軸方向の焦点位置（単位はミリメータ）を示す。図２０（ａ）の縦軸は、光線の絞りにおける通過位置を示す。縦軸の０は、光線が絞りの中心を通過することを示し、縦軸の１は、光線が絞りの端を通過することを示す。図２０（ｂ）は、非点収差および像面湾曲を示す図である。図２０（ｂ）の横軸は、光軸方向の焦点位置を示す（単位はミリメータ）。図２０（ｂ）の縦軸は、像高さ（単位はミリメータ）を示す。点線は子午像面の位置を表し、実線は球欠像面の位置を表す。図２０（ｃ）は、歪曲収差を示す図である。図２０（ｃ）の横軸は、歪曲収差（ディストーション）を示す。図２０（ｃ）の縦軸は、像高さ（単位はミリメータ）を示す。 FIG. 20 is a diagram illustrating aberrations of the imaging optical system according to the tenth embodiment. FIG. 20A is a diagram showing axial chromatic aberration. The horizontal axis of Fig.20 (a) shows the focus position (a unit is a millimeter) of an optical axis direction. The vertical axis in FIG. 20A indicates the passage position of the light beam in the aperture stop. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop. FIG. 20B is a diagram showing astigmatism and curvature of field. The horizontal axis in FIG. 20B indicates the focal position in the optical axis direction (unit: millimeter). The vertical axis in FIG. 20B indicates the image height (unit: millimeter). The dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane. FIG.20 (c) is a figure which shows a distortion aberration. The horizontal axis of FIG.20 (c) shows a distortion aberration (distortion). The vertical axis | shaft of FIG.20 (c) shows image height (a unit is a millimeter).
　表３０は、実施例１０による撮像光学系のレンズデータを示す表である。表３０において、絞りの面間隔は、絞りの位置を基準とし、像側をプラスとした場合の第２面の位置である。その他の面について、例として、第２面（第１レンズの物体側の面）の面間隔は、第２面と第３面（第２レンズの像側の面）との間隔である。 Table 30 is a table showing lens data of the imaging optical system according to Example 10. In Table 30, the diaphragm surface interval is the position of the second surface when the position of the diaphragm is a reference and the image side is positive. For other surfaces, as an example, the surface interval of the second surface (the object side surface of the first lens) is the interval between the second surface and the third surface (the image side surface of the second lens).
　表３１は、第２面乃至第７面の非球面形状を表す式の係数および定数を示す表である。 Table 31 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
　表３２は、回折格子の光路差関数の係数を示す表である。
Figure JPOXMLDOC01-appb-T000030
Figure JPOXMLDOC01-appb-T000031
Figure JPOXMLDOC01-appb-T000032
 Table 32 is a table | surface which shows the coefficient of the optical path difference function of a diffraction grating.
Figure JPOXMLDOC01-appb-T000030
Figure JPOXMLDOC01-appb-T000031
Figure JPOXMLDOC01-appb-T000032
実施例１１
　図２１は、実施例１１による撮像光学系の構成を示す図である。本実施形態による撮像光学系は、物体側から像側に、第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を備える。第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を通過した光は、ガラス板Ｅ４を通過して像面ＩＳに至る。 Example 11
FIG. 21 is a diagram illustrating the configuration of the imaging optical system according to the eleventh embodiment. The imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side. The light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
　図２２は、実施例１１による撮像光学系の収差を示す図である。図２２（ａ）は、軸上色収差を示す図である。図２２（ａ）の横軸は、光軸方向の焦点位置（単位はミリメータ）を示す。図２２（ａ）の縦軸は、光線の絞りにおける通過位置を示す。縦軸の０は、光線が絞りの中心を通過することを示し、縦軸の１は、光線が絞りの端を通過することを示す。図２２（ｂ）は、非点収差および像面湾曲を示す図である。図２２（ｂ）の横軸は、光軸方向の焦点位置を示す（単位はミリメータ）。図２２（ｂ）の縦軸は、像高さ（単位はミリメータ）を示す。点線は子午像面の位置を表し、実線は球欠像面の位置を表す。図２２（ｃ）は、歪曲収差を示す図である。図２２（ｃ）の横軸は、歪曲収差（ディストーション）を示す。図２２（ｃ）の縦軸は、像高さ（単位はミリメータ）を示す。 FIG. 22 shows aberrations of the image pickup optical system according to the eleventh embodiment. FIG. 22A is a diagram showing axial chromatic aberration. The horizontal axis of Fig.22 (a) shows the focus position (a unit is a millimeter) of an optical axis direction. The vertical axis | shaft of Fig.22 (a) shows the passage position in the aperture_diaphragm | restriction of a light ray. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop. FIG. 22B is a diagram showing astigmatism and field curvature. The horizontal axis of FIG.22 (b) shows the focus position of an optical axis direction (a unit is a millimeter). The vertical axis | shaft of FIG.22 (b) shows image height (a unit is a millimeter). The dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane. FIG. 22C is a diagram showing distortion. The horizontal axis of FIG.22 (c) shows a distortion aberration (distortion). The vertical axis | shaft of FIG.22 (c) shows image height (a unit is a millimeter).
　表３３は、実施例１１による撮像光学系のレンズデータを示す表である。表３３において、絞りの面間隔は、絞りの位置を基準とし、像側をプラスとした場合の第２面の位置である。その他の面について、例として、第２面（第１レンズの物体側の面）の面間隔は、第２面と第３面（第２レンズの像側の面）との間隔である。 Table 33 is a table showing lens data of the imaging optical system according to Example 11. In Table 33, the diaphragm surface interval is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive. For other surfaces, as an example, the surface interval of the second surface (the object side surface of the first lens) is the interval between the second surface and the third surface (the image side surface of the second lens).
　表３４は、第２面乃至第７面の非球面形状を表す式の係数および定数を示す表である。 Table 34 is a table showing the coefficients and constants of the expressions representing the aspherical shapes of the second surface to the seventh surface.
　表３５は、回折格子の光路差関数の係数を示す表である。
Figure JPOXMLDOC01-appb-T000033
Figure JPOXMLDOC01-appb-T000034
Figure JPOXMLDOC01-appb-T000035
 Table 35 is a table | surface which shows the coefficient of the optical path difference function of a diffraction grating.
Figure JPOXMLDOC01-appb-T000033
Figure JPOXMLDOC01-appb-T000034
Figure JPOXMLDOC01-appb-T000035
実施例１２
　図２３は、実施例１２による撮像光学系の構成を示す図である。本実施形態による撮像光学系は、物体側から像側に、第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を備える。第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を通過した光は、ガラス板Ｅ４を通過して像面ＩＳに至る。 Example 12
FIG. 23 is a diagram illustrating the configuration of the imaging optical system according to the twelfth embodiment. The imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side. The light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
　図２４は、実施例１２による撮像光学系の収差を示す図である。図２４（ａ）は、軸上色収差を示す図である。図２４（ａ）の横軸は、光軸方向の焦点位置（単位はミリメータ）を示す。図２４（ａ）の縦軸は、光線の絞りにおける通過位置を示す。縦軸の０は、光線が絞りの中心を通過することを示し、縦軸の１は、光線が絞りの端を通過することを示す。図２４（ｂ）は、非点収差および像面湾曲を示す図である。図２４（ｂ）の横軸は、光軸方向の焦点位置を示す（単位はミリメータ）。図２４（ｂ）の縦軸は、像高さ（単位はミリメータ）を示す。点線は子午像面の位置を表し、実線は球欠像面の位置を表す。図２４（ｃ）は、歪曲収差を示す図である。図２４（ｃ）の横軸は、歪曲収差（ディストーション）を示す。図２４（ｃ）の縦軸は、像高さ（単位はミリメータ）を示す。 FIG. 24 is a diagram showing aberrations of the image pickup optical system according to the twelfth embodiment. FIG. 24A is a diagram showing axial chromatic aberration. The horizontal axis of Fig.24 (a) shows the focus position (a unit is a millimeter) of an optical axis direction. The vertical axis | shaft of Fig.24 (a) shows the passage position in the aperture_diaphragm | restriction of a light ray. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop. FIG. 24B is a diagram showing astigmatism and field curvature. The horizontal axis of FIG.24 (b) shows the focus position of an optical axis direction (a unit is a millimeter). The vertical axis | shaft of FIG.24 (b) shows image height (a unit is a millimeter). The dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane. FIG. 24C is a diagram showing distortion. The horizontal axis of FIG.24 (c) shows a distortion aberration (distortion). The vertical axis | shaft of FIG.24 (c) shows image height (a unit is a millimeter).
　表３６は、実施例１２による撮像光学系のレンズデータを示す表である。表３６において、絞りの面間隔は、絞りの位置を基準とし、像側をプラスとした場合の第２面の位置である。その他の面について、例として、第２面（第１レンズの物体側の面）の面間隔は、第２面と第３面（第２レンズの像側の面）との間隔である。 Table 36 is a table showing lens data of the imaging optical system according to Example 12. In Table 36, the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive. For other surfaces, as an example, the surface interval of the second surface (the object side surface of the first lens) is the interval between the second surface and the third surface (the image side surface of the second lens).
　表３７は、第２面乃至第７面の非球面形状を表す式の係数および定数を示す表である。 Table 37 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
　表３８は、回折格子の光路差関数の係数を示す表である。
Figure JPOXMLDOC01-appb-T000036
Figure JPOXMLDOC01-appb-T000037
Figure JPOXMLDOC01-appb-T000038
 Table 38 is a table | surface which shows the coefficient of the optical path difference function of a diffraction grating.
Figure JPOXMLDOC01-appb-T000036
Figure JPOXMLDOC01-appb-T000037
Figure JPOXMLDOC01-appb-T000038
実施例１３
　図２５は、実施例１３による撮像光学系の構成を示す図である。本実施形態による撮像光学系は、物体側から像側に、第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を備える。第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を通過した光は、ガラス板Ｅ４を通過して像面ＩＳに至る。 Example 13
FIG. 25 is a diagram illustrating the configuration of the imaging optical system according to the thirteenth embodiment. The imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side. The light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
　図２６は、実施例１３による撮像光学系の収差を示す図である。図２６（ａ）は、軸上色収差を示す図である。図２６（ａ）の横軸は、光軸方向の焦点位置（単位はミリメータ）を示す。図２６（ａ）の縦軸は、光線の絞りにおける通過位置を示す。縦軸の０は、光線が絞りの中心を通過することを示し、縦軸の１は、光線が絞りの端を通過することを示す。図２６（ｂ）は、非点収差および像面湾曲を示す図である。図２６（ｂ）の横軸は、光軸方向の焦点位置を示す（単位はミリメータ）。図２６（ｂ）の縦軸は、像高さ（単位はミリメータ）を示す。点線は子午像面の位置を表し、実線は球欠像面の位置を表す。図２６（ｃ）は、歪曲収差を示す図である。図２６（ｃ）の横軸は、歪曲収差（ディストーション）を示す。図２６（ｃ）の縦軸は、像高さ（単位はミリメータ）を示す。 FIG. 26 is a diagram illustrating aberrations of the imaging optical system according to the thirteenth embodiment. FIG. 26A is a diagram showing axial chromatic aberration. The horizontal axis of Fig.26 (a) shows the focus position (a unit is a millimeter) of an optical axis direction. The vertical axis | shaft of Fig.26 (a) shows the passage position in the aperture_diaphragm | restriction of a light ray. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop. FIG. 26B is a diagram showing astigmatism and curvature of field. The horizontal axis of FIG.26 (b) shows the focus position of an optical axis direction (a unit is a millimeter). The vertical axis | shaft of FIG.26 (b) shows image height (a unit is a millimeter). The dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane. FIG. 26C is a diagram showing distortion. The horizontal axis of FIG.26 (c) shows a distortion aberration (distortion). The vertical axis | shaft of FIG.26 (c) shows image height (a unit is a millimeter).
　表３９は、実施例１３による撮像光学系のレンズデータを示す表である。表３９において、絞りの面間隔は、絞りの位置を基準とし、像側をプラスとした場合の第２面の位置である。その他の面について、例として、第２面（第１レンズの物体側の面）の面間隔は、第２面と第３面（第２レンズの像側の面）との間隔である。 Table 39 is a table showing lens data of the imaging optical system according to Example 13. In Table 39, the diaphragm surface interval is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive. For other surfaces, as an example, the surface interval of the second surface (the object side surface of the first lens) is the interval between the second surface and the third surface (the image side surface of the second lens).
　表４０は、第２面乃至第７面の非球面形状を表す式の係数および定数を示す表である。 Table 40 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
　表４１は、回折格子の光路差関数の係数を示す表である。
Figure JPOXMLDOC01-appb-T000039
Figure JPOXMLDOC01-appb-T000040
Figure JPOXMLDOC01-appb-T000041
 Table 41 is a table | surface which shows the coefficient of the optical path difference function of a diffraction grating.
Figure JPOXMLDOC01-appb-T000039
Figure JPOXMLDOC01-appb-T000040
Figure JPOXMLDOC01-appb-T000041
実施例１４
　図２７は、実施例１４による撮像光学系の構成を示す図である。本実施形態による撮像光学系は、物体側から像側に、第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を備える。第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を通過した光は、ガラス板Ｅ４を通過して像面ＩＳに至る。 Example 14
FIG. 27 is a diagram illustrating the configuration of the imaging optical system according to the fourteenth embodiment. The imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side. The light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
　図２８は、実施例１４による撮像光学系の収差を示す図である。図２８（ａ）は、軸上色収差を示す図である。図２８（ａ）の横軸は、光軸方向の焦点位置（単位はミリメータ）を示す。図２８（ａ）の縦軸は、光線の絞りにおける通過位置を示す。縦軸の０は、光線が絞りの中心を通過することを示し、縦軸の１は、光線が絞りの端を通過することを示す。図２８（ｂ）は、非点収差および像面湾曲を示す図である。図２８（ｂ）の横軸は、光軸方向の焦点位置を示す（単位はミリメータ）。図２８（ｂ）の縦軸は、像高さ（単位はミリメータ）を示す。点線は子午像面の位置を表し、実線は球欠像面の位置を表す。図２８（ｃ）は、歪曲収差を示す図である。図２８（ｃ）の横軸は、歪曲収差（ディストーション）を示す。図２８（ｃ）の縦軸は、像高さ（単位はミリメータ）を示す。 FIG. 28 is a diagram showing aberrations of the imaging optical system according to Example 14. FIG. 28A is a diagram showing axial chromatic aberration. The horizontal axis of Fig.28 (a) shows the focus position (a unit is a millimeter) of an optical axis direction. The vertical axis | shaft of Fig.28 (a) shows the passage position in the aperture_diaphragm | restriction of a light ray. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop. FIG. 28B is a diagram showing astigmatism and curvature of field. The horizontal axis of FIG.28 (b) shows the focus position of an optical axis direction (a unit is a millimeter). The vertical axis | shaft of FIG.28 (b) shows image height (a unit is a millimeter). The dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane. FIG. 28 (c) is a diagram showing distortion aberration. The horizontal axis of FIG.28 (c) shows a distortion aberration (distortion). The vertical axis | shaft of FIG.28 (c) shows image height (a unit is a millimeter).
　表４２は、実施例１４による撮像光学系のレンズデータを示す表である。表４２において、絞りの面間隔は、絞りの位置を基準とし、像側をプラスとした場合の第２面の位置である。その他の面について、例として、第２面（第１レンズの物体側の面）の面間隔は、第２面と第３面（第２レンズの像側の面）との間隔である。 Table 42 is a table showing lens data of the imaging optical system according to Example 14. In Table 42, the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive. For other surfaces, as an example, the surface interval of the second surface (the object side surface of the first lens) is the interval between the second surface and the third surface (the image side surface of the second lens).
　表４３は、第２面乃至第７面の非球面形状を表す式の係数および定数を示す表である。 Table 43 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the seventh surface.
　表４４は、回折格子の光路差関数の係数を示す表である。
Figure JPOXMLDOC01-appb-T000042
Figure JPOXMLDOC01-appb-T000043
Figure JPOXMLDOC01-appb-T000044
 Table 44 is a table | surface which shows the coefficient of the optical path difference function of a diffraction grating.
Figure JPOXMLDOC01-appb-T000042
Figure JPOXMLDOC01-appb-T000043
Figure JPOXMLDOC01-appb-T000044
実施例１５
　図２９は、実施例１５による撮像光学系の構成を示す図である。本実施形態による撮像光学系は、物体側から像側に、第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を備える。第１レンズＥ１、第２レンズＥ２及び第３レンズＥ３を通過した光は、ガラス板Ｅ４を通過して像面ＩＳに至る。 Example 15
FIG. 29 is a diagram illustrating the configuration of the imaging optical system according to the fifteenth embodiment. The imaging optical system according to the present embodiment includes a first lens E1, a second lens E2, and a third lens E3 from the object side to the image side. The light that has passed through the first lens E1, the second lens E2, and the third lens E3 passes through the glass plate E4 and reaches the image plane IS.
　図３０は、実施例１５による撮像光学系の収差を示す図である。図３０（ａ）は、軸上色収差を示す図である。図３０（ａ）の横軸は、光軸方向の焦点位置（単位はミリメータ）を示す。図３０（ａ）の縦軸は、光線の絞りにおける通過位置を示す。縦軸の０は、光線が絞りの中心を通過することを示し、縦軸の１は、光線が絞りの端を通過することを示す。図３０（ｂ）は、非点収差および像面湾曲を示す図である。図３０（ｂ）の横軸は、光軸方向の焦点位置を示す（単位はミリメータ）。図３０（ｂ）の縦軸は、像高さ（単位はミリメータ）を示す。点線は子午像面の位置を表し、実線は球欠像面の位置を表す。図３０（ｃ）は、歪曲収差を示す図である。図３０（ｃ）の横軸は、歪曲収差（ディストーション）を示す。図３０（ｃ）の縦軸は、像高さ（単位はミリメータ）を示す。 FIG. 30 is a diagram illustrating aberrations of the imaging optical system according to the fifteenth embodiment. FIG. 30A is a diagram showing axial chromatic aberration. The horizontal axis of Fig.30 (a) shows the focus position (a unit is a millimeter) of an optical axis direction. The vertical axis in FIG. 30 (a) indicates the passage position of the light beam. 0 on the vertical axis indicates that the light beam passes through the center of the stop, and 1 on the vertical axis indicates that the light beam passes through the end of the stop. FIG. 30B is a diagram showing astigmatism and curvature of field. The horizontal axis of FIG.30 (b) shows the focus position of an optical axis direction (a unit is a millimeter). The vertical axis | shaft of FIG.30 (b) shows image height (a unit is a millimeter). The dotted line represents the position of the meridian image plane, and the solid line represents the position of the spherical image plane. FIG.30 (c) is a figure which shows a distortion aberration. The horizontal axis of FIG.30 (c) shows a distortion aberration (distortion). The vertical axis | shaft of FIG.30 (c) shows image height (a unit is a millimeter).
　表４５は、実施例１５による撮像光学系のレンズデータを示す表である。表４５において、絞りの面間隔は、絞りの位置を基準とし、像側をプラスとした場合の第２面の位置である。その他の面について、例として、第２面（第１レンズの物体側の面）の面間隔は、第２面と第３面（第２レンズの像側の面）との間隔である。 Table 45 is a table showing lens data of the imaging optical system according to Example 15. In Table 45, the distance between the diaphragm surfaces is the position of the second surface when the position of the diaphragm is used as a reference and the image side is positive. For other surfaces, as an example, the surface interval of the second surface (the object side surface of the first lens) is the interval between the second surface and the third surface (the image side surface of the second lens).
　表４６は、第２面乃至第５面及び第７面の非球面形状を表す式の係数および定数を示す表である。 Table 46 is a table showing coefficients and constants of expressions representing the aspherical shapes of the second surface to the fifth surface and the seventh surface.
　表４７は、回折格子の光路差関数の係数を示す表である。 Table 47 is a table showing coefficients of the optical path difference function of the diffraction grating.
　表４８は、第６面の特殊面形状を表す式の係数および定数を示す表である。撮像光学系の光軸をｚ軸とし、光軸に垂直な面の座標をｘ、ｙとする直交座標系において、特殊面形状は、以下の式で表される２次曲線を、光軸、すなわちｚ軸の周りに回転させた光軸対称回転面である。ただし、ｋｊは２次曲線の形状を定める定数、ｃｊは中心曲率、ｄｊは面の位置を定める定数である。また、Ａｉｊは補正係数である。特殊面は、光軸を含む中心領域とその周囲の帯状領域から構成される。中心領域（ｊ＝１）と帯状領域（ｊ≧２)との境界及び複数の帯状領域が存在する場合に隣接する帯状領域の境界は円であり、この円を境界円と呼称する。本例においては、中心領域（ｊ＝１）と１個の帯状領域（ｊ＝２）が存在する。表４８において、ｊ＝２の境界円は、中心領域と１個の帯状領域の境界円である。
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-T000045
Figure JPOXMLDOC01-appb-T000046
Figure JPOXMLDOC01-appb-T000047
Figure JPOXMLDOC01-appb-T000048
 Table 48 is a table | surface which shows the coefficient and constant of a formula showing the special surface shape of a 6th surface. In an orthogonal coordinate system in which the optical axis of the imaging optical system is the z-axis and the coordinates of the plane perpendicular to the optical axis are x and y, the special surface shape is a quadratic curve represented by the following equation: That is, it is an optical axis symmetric rotation surface rotated about the z axis. Here, k j is a constant that determines the shape of the quadratic curve, c j is the center curvature, and d j is a constant that determines the position of the surface. A ij is a correction coefficient. The special surface is composed of a central region including the optical axis and a belt-like region around it. The boundary between the central region (j = 1) and the belt-like region (j ≧ 2) and the border between adjacent belt-like regions when there are a plurality of belt-like regions are circles, and this circle is called a border circle. In this example, there is a central region (j = 1) and one strip region (j = 2). In Table 48, the boundary circle of j = 2 is a boundary circle between the central region and one strip region.
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-T000045
Figure JPOXMLDOC01-appb-T000046
Figure JPOXMLDOC01-appb-T000047
Figure JPOXMLDOC01-appb-T000048

Claims (10)

  1. 　物体側から像側に、像側に回折格子が付された正の第１レンズ、像側に凸面を向けたメニスカスレンズである第２レンズ、負のメニスカスレンズである第３レンズから構成され、絞りが第１レンズの像側の面よりも物体側に配置された撮像光学系であって、Ｄ１２は第１レンズ及び第２レンズ間の光軸上の距離、ＴＴＬは第１レンズの物体側の頂点から像面までの距離、φ１は、第１レンズのパワー、φ２は、第２レンズのパワー、φは、第１レンズ、第２レンズ及び第３レンズの合成パワー、Ｆｎｏは光学系のエフ・ナンバー、ｒ１は、第１レンズの物体側の面の曲率半径であるとして、
    　0.18<D12×φ<0.22　　　　(1)
    　1.1<TTL×φ<1.22　　　   (2)
    　Fno<3.0　　　　　　　　　(3)
    　0.46<r1×φ<0.49　 　　　(4)
    　0.8<φ/φ1<1.0　　　　   (5)
    　|φ2/φ|<0.1　　　　　　 (6)
    を満足する撮像光学系。     A positive first lens with a diffraction grating attached to the image side from the object side to the image side, a second lens that is a meniscus lens with a convex surface facing the image side, and a third lens that is a negative meniscus lens, An imaging optical system in which the stop is disposed on the object side of the image side surface of the first lens, D12 is the distance on the optical axis between the first lens and the second lens, and TTL is the object side of the first lens The distance from the apex to the image plane, φ1 is the power of the first lens, φ2 is the power of the second lens, φ is the combined power of the first lens, the second lens, and the third lens, and Fno is the optical system The F number, r1, is the radius of curvature of the object side surface of the first lens.
    0.18 <D12 × φ <0.22 (1)
    1.1 <TTL × φ <1.22 (2)
    Fno <3.0 (3)
    0.46 <r1 × φ <0.49 (4)
    0.8 <φ / φ1 <1.0 (5)
    | φ2 / φ | <0.1 (6)
    Imaging optical system that satisfies
  2. 　第２レンズは、近軸領域から周辺に向かって像側の面の負のパワーが強くなる、パワー０のメニスカスレンズである請求項１に記載の撮像光学系。 2. The imaging optical system according to claim 1, wherein the second lens is a meniscus lens having a power of 0 in which the negative power of the image side surface increases from the paraxial region toward the periphery.
  3. 　第１レンズが近軸領域において、凸平または両凸レンズである請求項１または２に記載の撮像光学系。 The imaging optical system according to claim 1 or 2, wherein the first lens is a convex or biconvex lens in the paraxial region.
  4. 　第３レンズの物体側の面は、近軸領域及び周辺領域において正のパワーを有し、該近軸領域と該周辺領域の中間領域で負のパワーを有する請求項１から３のいずれかに記載の撮像光学系。 The object side surface of the third lens has a positive power in the paraxial region and the peripheral region, and has a negative power in an intermediate region between the paraxial region and the peripheral region. The imaging optical system described.
  5. 　第３レンズの像側の面は、近軸領域において負のパワーを有し、周辺領域において正のパワーを有する請求項１から４のいずれかに記載の撮像光学系。 5. The imaging optical system according to claim 1, wherein the image side surface of the third lens has a negative power in the paraxial region and a positive power in the peripheral region.
  6. 　φ３は、第３レンズのパワーであるとして、
    　-3.3<φ/φ3<-2.6　　　　 (7)
    を満足する請求項１から５のいずれかに記載の撮像光学系。     φ3 is the power of the third lens,
    -3.3 <φ / φ3 <-2.6 (7)
    The imaging optical system according to claim 1, wherein:
  7. 　ｖd1は第１レンズの材料のｄ線(波長587.6nm)でのアッべ数、ｖd3は第３レンズの材料のｄ線(波長587.6nm)でのアッべ数、 nd1は第１レンズの材料のｄ線(波長587.6nm)での屈性率、nd3は第三レンズの材料のｄ線(波長587.6nm)での屈折率であるとして、
    　54<vd1,vd3<58　　　　   　 (8)
    　1.5<nd1,nd3<1.54　　　　　 (9)
    を満足する請求項１から６のいずれかに記載の撮像光学系。     v d 1 is the Abbe number of the first lens material at the d-line (wavelength 587.6 nm), v d 3 is the Abbe number of the third lens material at the d-line (wavelength 587.6 nm), and n d 1 is It is assumed that the refractive index at the d-line (wavelength 587.6 nm) of the material of the first lens and n d 3 is the refractive index at the d-line (wavelength 587.6 nm) of the material of the third lens.
    54 <v d 1, v d 3 <58 (8)
    1.5 <n d 1, n d 3 <1.54 (9)
    The imaging optical system according to claim 1, wherein:
  8. 　nd2は第２レンズの材料のｄ線(波長587.6nm)での屈折率、r3は第２レンズ物体側の曲率半径、r4は第２レンズの像側の曲率半径、D2は第２レンズの中心厚であるとして、
    　　(nd2-1)×(1/r3-1/r4)+(nd2-1)2×D2/(nd2×r3×r4)=0　　 (10)
    を満足する請求項１から７のいずれかに記載の撮像光学系。     n d 2 is the refractive index of the second lens material at the d-line (wavelength 587.6 nm), r 3 is the radius of curvature on the second lens object side, r 4 is the radius of curvature of the second lens on the image side, and D 2 is the second lens. As the center thickness of
    (n d 2-1) × (1 / r3-1 / r4) + (n d 2-1) 2 × D2 / (n d 2 × r3 × r4) = 0 (10)
    The imaging optical system according to any one of claims 1 to 7, wherein:
  9. 　φDOEは第１レンズの回折格子のパワーであるとして、
    　0.05<φDOE/φ<0.07　　 (11)
    を満足する請求項１から８のいずれかに記載の撮像光学系。     φDOE is the power of the diffraction grating of the first lens.
    0.05 <φDOE / φ <0.07 (11)
    The imaging optical system according to claim 1, wherein:
  10. 　0.27<Fno<3.0　　　　　 (12)
    を満足する請求項１から９のいずれかに記載の撮像光学系。     0.27 <Fno <3.0 (12)
    The imaging optical system according to any one of claims 1 to 9, wherein:
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