WO2020039912A1 - Système optique, dispositif optique, et procédé de fabrication d'un système optique - Google Patents

Système optique, dispositif optique, et procédé de fabrication d'un système optique Download PDF

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Publication number
WO2020039912A1
WO2020039912A1 PCT/JP2019/030872 JP2019030872W WO2020039912A1 WO 2020039912 A1 WO2020039912 A1 WO 2020039912A1 JP 2019030872 W JP2019030872 W JP 2019030872W WO 2020039912 A1 WO2020039912 A1 WO 2020039912A1
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lens
optical system
group
lens group
focusing
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PCT/JP2019/030872
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English (en)
Japanese (ja)
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壮基 原田
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株式会社ニコン
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Priority to JP2020538283A priority Critical patent/JP7099529B2/ja
Publication of WO2020039912A1 publication Critical patent/WO2020039912A1/fr

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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

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  • the present invention relates to an optical system, an optical device, and a method for manufacturing an optical system.
  • a first aspect of the present invention provides: A first lens group having a positive refractive power and a plurality of subsequent lens groups in order from the object side, During focusing, the distance between adjacent lens groups changes,
  • the first lens group includes a front lens group having a positive refractive power disposed on the object side, and a rear lens group having a positive refractive power disposed on the image side, with the aperture stop interposed therebetween.
  • the front lens group moves toward the object side during focusing from an object at infinity to an object at a short distance
  • m and n are positive integers satisfying m ⁇ n, and the object at infinity at the m-th and n-th lens surfaces counted from the lens surface closest to the object in the rear lens unit.
  • the optical system satisfies the following conditional expression when (max) is set and h (n) is set to h (min). 0.50 ⁇ h (min) / h (max)
  • a second aspect of the present invention provides A first lens group having a positive refractive power and a plurality of subsequent lens groups in order from the object side, During focusing, the distance between adjacent lens groups changes,
  • the first lens group includes a front lens group having a positive refractive power disposed on the object side, and a rear lens group having a positive refractive power disposed on the image side, with the aperture stop interposed therebetween.
  • the front lens group moves toward the object side during focusing from an object at infinity to an object at a short distance
  • the front lens unit further sets a marginal ray height at the most object side lens surface of the front lens unit at the time of focusing on an object at infinity to h (1), and sets m and n to an integer of 2 or more that satisfies m ⁇ n.
  • h (m) and h (n) are the marginal ray heights at the m-th and n-th lens surfaces counted from the lens surface closest to the object, respectively, and h (1)> h ( m) and h (m) ⁇ h (n), among the marginal ray heights, h (m) is the lowest h (min), and h (n) is the highest h (n).
  • the optical system satisfies the following conditional expressions. 0.10 ⁇ h (max) -h (min) ⁇ / ⁇ h (1) -h (min) ⁇
  • a first set that is a set of lenses whose concave surfaces face each other and a second set that is a set of lenses whose concave surfaces face each other, Having at least one positive lens between the first set and the second set; Having at least one positive lens on the object side of the first set; Having at least four positive lenses on the image side of the second set;
  • the optical system uses three or more types of glass materials.
  • a method for manufacturing an optical system including a first lens group having a positive refractive power and a plurality of subsequent lens groups in order from the object side, During focusing, the distance between adjacent lens groups is changed,
  • the first lens group includes a front lens group having a positive refractive power disposed on the object side and a rear lens group having a positive refractive power disposed on the image side, with the aperture stop interposed therebetween.
  • the front lens group is configured to move to the object side during focusing from an object at infinity to an object at a short distance
  • the rear lens unit may be configured such that m and n are positive integers satisfying m ⁇ n, and the object at infinity at the m-th and n-th lens surfaces counted from the most object-side lens surface of the rear lens unit.
  • the marginal ray heights at the time of focusing are h (m) and h (n)
  • the highest h (m) among the marginal ray heights satisfying h (m)> h (n) is h.
  • (Max) and the lowest h (n) is h (min).
  • FIG. 1 is a sectional view of the optical system according to the first embodiment.
  • 2A and 2B are graphs showing various aberrations of the optical system according to Example 1 when focusing on an object at infinity and when focusing on a short-distance object, respectively.
  • FIGS. 3A and 3B are aberration diagrams of the optical system according to the first example when the DC unit moves to the object side and the DC unit moves to the image side when focusing on an object at infinity.
  • 4A and 4B are graphs showing various aberrations in a state where the DC group moves to the object side and a state where the DC group moves to the image side when the optical system according to the first example focuses on a short-distance object. .
  • FIG. 1 is a sectional view of the optical system according to the first embodiment.
  • 2A and 2B are graphs showing various aberrations of the optical system according to Example 1 when focusing on an object at infinity and when focusing on a short-distance object, respectively.
  • FIGS. 6A and 6B are graphs showing various aberrations of the optical system according to Example 2 when focusing on an object at infinity and when focusing on a close object.
  • 7A and 7B are graphs showing various aberrations when the DC unit moves to the object side and the DC unit moves to the image side when the optical system according to Example 2 is focused on an object at infinity.
  • 8A and 8B are graphs showing various aberrations in a state where the DC unit moves to the object side and a state where the DC unit moves to the image side when the optical system according to the second example focuses on a short-distance object.
  • FIG. 9 is a sectional view of an optical system according to the third example.
  • FIGS. 10A and 10B are graphs showing various aberrations of the optical system according to Example 3 upon focusing on an object at infinity and on focusing on a close object.
  • FIGS. 11A and 11B are graphs showing various aberrations in a state where the DC group moves to the object side and a state where the DC group moves to the image side when the optical system according to Example 3 is focused on an object at infinity.
  • . 12A and 12B are graphs showing various aberrations when the DC unit moves to the object side and the DC unit moves to the image side when the optical system according to Example 3 is focused on a short-distance object.
  • FIG. 13 is a sectional view of an optical system according to the fourth example.
  • FIGS. 14A and 14B are graphs showing various aberrations of the optical system according to Example 4 when focusing on an object at infinity and when focusing on a short-distance object, respectively.
  • FIGS. 15A and 15B are graphs showing various aberrations when the optical system according to Example 4 is focused on an object at infinity and the DC unit is moved to the object side and the DC unit is moved to the image side.
  • . 16A and 16B are aberration diagrams of the optical system according to Example 4 when the DC unit is moved to the object side and when the DC unit is moved to the image side when a short-distance object is focused.
  • FIG. 17 is a sectional view of an optical system according to the fifth example.
  • FIG. 18A and 18B are graphs showing various aberrations of the optical system according to Example 5 upon focusing on an object at infinity and upon focusing on a close object.
  • 19A and 19B are graphs showing various aberrations in a state where the DC group moves to the object side and a state where the DC group moves to the image side when the optical system according to Example 5 is focused on an object at infinity.
  • 20A and 20B are graphs showing various aberrations in a state where the DC unit moves to the object side and a state where the DC unit moves to the image side when the optical system according to the fifth example focuses on a short-distance object.
  • FIG. 21 is a sectional view of the optical system according to the sixth example.
  • FIGS. 22A and 22B are graphs showing various aberrations of the optical system according to Example 6 upon focusing on an object at infinity and upon focusing on an object at a short distance.
  • FIGS. 23A and 23B are graphs showing various aberrations in a state where the DC unit moves to the object side and a state where the DC unit moves to the image side when the optical system according to the sixth example is focused on an object at infinity.
  • FIGS. 24A and 24B are graphs showing various aberrations when the DC unit moves to the object side and the DC unit moves to the image side when the optical system according to Example 6 is focused on a short-distance object.
  • FIG. 25 is a diagram illustrating a configuration of a camera including an optical system.
  • FIG. 26 is a flowchart showing an outline of a method of manufacturing an optical system.
  • the optical system according to the present embodiment includes, in order from the object side, a first lens group having a positive refractive power and a plurality of subsequent lens groups. During focusing, an interval between adjacent lens groups changes.
  • the first lens group includes a front lens group having a positive refractive power disposed on the object side, and a rear lens group having a positive refractive power disposed on the image side, with the aperture stop interposed therebetween.
  • the front lens group moves to the object side when focusing from an object at infinity to an object at a short distance.
  • the optical system of the present embodiment can satisfactorily correct various aberrations, particularly spherical aberration and coma, from the in-focus state of an object at infinity to the in-focus state of a close object.
  • the rear lens group is configured such that m and n are positive integers satisfying m ⁇ n, and the rear lens group is arranged from the most object side lens surface of the rear lens group.
  • h (m) and h (n) are positive integers satisfying m ⁇ n
  • h (m)> h (n) is satisfied.
  • the highest h (m) is h (max) and the lowest h (n) is h (min)
  • the following conditional expression (1) is satisfied. (1) 0.50 ⁇ h (min) / h (max)
  • marginal ray refers to a ray having the highest incident light among incident light fluxes parallel to the optical axis.
  • the “marginal ray height” is the distance from the optical axis to the marginal ray (the distance in a direction perpendicular to the optical axis).
  • Conditional expression (1) is a conditional expression that defines the ratio between the lowest marginal ray height and the highest marginal ray height in the rear lens unit.
  • conditional expression (1) of the present embodiment When the corresponding value of the conditional expression (1) of the present embodiment is below the lower limit, the height of the marginal ray on the object-side lens surface of the rear lens unit becomes low, and the spherical aberration and coma aberration in the rear lens unit become good. It becomes difficult to make corrections.
  • the lower limit of conditional expression (1) By setting the lower limit of conditional expression (1) to 0.60, the effect of the present embodiment can be made more reliable.
  • the optical system of the present embodiment can satisfactorily correct various aberrations from an in-focus object state to a close-distance object focus state, and is suitable for both auto focus and manual focus.
  • a large-diameter optical system can be realized.
  • the optical system includes, in order from the object side, a first lens group having a positive refractive power and a plurality of subsequent lens groups. During focusing, an interval between adjacent lens groups changes.
  • the first lens group includes a front lens group having a positive refractive power disposed on the object side, and a rear lens group having a positive refractive power disposed on the image side, with the aperture stop interposed therebetween.
  • the front lens group moves to the object side when focusing from an object at infinity to an object at a short distance.
  • the optical system according to the present embodiment can satisfactorily correct various aberrations, particularly spherical aberration and coma, from an in-focus object state to a close-distance object focus state.
  • the front lens unit sets the marginal ray height of the front lens unit at the most object side lens surface at the time of focusing on an object at infinity to h (1).
  • m and n are integers of 2 or more satisfying m ⁇ n, and the marginal ray heights at the m-th and n-th lens surfaces counted from the lens surface closest to the object are h (m) and h (m), respectively.
  • Conditional expression (2) represents the difference between the highest marginal ray height and the lowest marginal ray height in the front lens group, and the marginal ray height and the lowest marginal ray height of the most object side lens surface of the front lens group. It is a conditional expression which defines the ratio with the difference.
  • conditional expression (2) the distance between the marginal ray and the optical axis becomes shorter after passing through the lens surface closest to the object side of the front lens group before the aperture stop, and thereafter, Takes an optical path that increases the distance of
  • the optical system according to the present embodiment can reduce Petzval sum by providing an area in which the marginal ray height is lower in front of the aperture stop, and can correct field curvature satisfactorily.
  • conditional expression (2) of the present embodiment If the corresponding value of the conditional expression (2) of the present embodiment is below the lower limit, the area where the marginal ray height is low is not sufficiently formed, so that the Petzval sum cannot be sufficiently reduced, and the field curvature is good. It becomes difficult to make corrections.
  • the lower limit of conditional expression (2) By setting the lower limit of conditional expression (2) to 0.12, the effect of the present embodiment can be made more reliable. In order to further secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (2) to 0.15, more preferably 0.18.
  • the optical system of the present embodiment can satisfactorily correct various aberrations from an in-focus object state to a close-distance object focus state, and is suitable for both auto focus and manual focus.
  • a large-diameter optical system can be realized.
  • the rear lens group includes at least one or more lens groups that move during focusing.
  • the rear lens group includes at least two negative lenses and at least two positive lenses.
  • the optical system according to the present embodiment has a configuration in which at least two negative lenses and at least two positive lenses are provided in the rear lens group adjacent to the rear side of the aperture stop. , And the curvature of field can be more favorably corrected.
  • the “lens component” refers to a cemented lens formed by joining two or more lenses, or a single lens.
  • the front lens group has at least four lens components.
  • spherical aberration and coma can be effectively reduced irrespective of the focusing distance.
  • the first lens group includes at least one negative lens satisfying the following conditional expression (3).
  • (3) 0.600 ⁇ gFLn + 0.0021 ⁇ ⁇ dLn ⁇ 0.658
  • ⁇ dLn Abbe number of the negative lens with respect to d-line
  • ⁇ gFLn partial dispersion ratio between the g-line and the F-line of the negative lens
  • the Abbe number ⁇ dLn and the partial dispersion ratio ⁇ gFLn are nC for the refractive index for the C line (wavelength 656.3 nm), nd for the refractive index for the d line (wavelength 587.6 nm), and nd for the F line (wavelength 486.1 nm).
  • the refractive index is nF
  • the refractive index with respect to the g-line is ng
  • ⁇ dLn (nd ⁇ 1) / (nF ⁇ nC)
  • ⁇ gFLn (ng ⁇ nF) / (nF ⁇ nC)
  • conditional expression (3) is a conditional expression that defines a glass material used for the negative lens of the first lens group.
  • conditional expression (3) of the optical system according to the present embodiment exceeds the upper limit, the anomalous dispersion of the negative lens increases, and it becomes difficult to correct axial chromatic aberration.
  • the upper limit of conditional expression (3) it is preferable to set the upper limit of conditional expression (3) to 0.656, more preferably 0.655.
  • conditional expression (3) of the optical system according to the present embodiment when the corresponding value of the conditional expression (3) of the optical system according to the present embodiment is below the lower limit, the anomalous dispersion of the negative lens becomes small, and it becomes difficult to correct axial chromatic aberration.
  • the lower limit of conditional expression (3) By setting the lower limit of conditional expression (3) to 0.610, the effect of the present embodiment can be further ensured.
  • the optical system of the present embodiment satisfies the following conditional expression (4).
  • f (1F to 1R) composite focal length of the front lens group and the rear lens group when focusing on an object at infinity
  • f focal length of the entire optical system when focusing on an object at infinity
  • Conditional expression (4) defines a composite focal length of the front lens group and the rear lens group when focusing on an object at infinity, that is, a focal length of the first lens group when focusing on an object at infinity, and an object at infinity. It is a conditional expression which specifies the ratio with the focal length of the whole optical system at the time of focusing.
  • conditional expression (4) of the optical system according to the present embodiment exceeds the upper limit, the refractive power of the first lens group becomes weak, and it becomes difficult to satisfactorily correct spherical aberration and coma. .
  • the upper limit of conditional expression (4) it is preferable to set the upper limit of conditional expression (4) to 1.300, 1.250, 1.200, and more preferably 1.150.
  • the corresponding value of the conditional expression (4) of the optical system according to the present embodiment is below the lower limit, the power of the first lens unit becomes strong, and it becomes difficult to satisfactorily correct coma.
  • the lower limit of conditional expression (4) it is preferable to set the lower limit of conditional expression (4) to 0.850, more preferably 0.880, 0.900 and 0.920.
  • the optical system according to the present embodiment includes, in order from the object side, a first set that is a set of lenses whose concave surfaces face each other, and a second set that is a set of lenses whose concave surfaces face each other. Having at least one positive lens between the first set and the second set, having at least one positive lens on the object side of the first set, There are at least four positive lenses on the side, and three or more types of glass materials are used.
  • the optical system according to the present embodiment includes, in order from the object side, a first set that is a set of lenses whose concave surfaces face each other, and a second set that is a set of lenses whose concave surfaces face each other, By arranging at least one positive lens between the two sets of lenses, the first set and the second set contribute to reducing the Petzval sum, thereby favorably correcting the field curvature. At the same time, the deterioration of coma and spherical aberration is suppressed.
  • the optical system of the present embodiment reduces the height of off-axis light rays incident on the first set by arranging at least one positive lens on the object side of the first set.
  • the refractive powers of the first set and the second set are set to appropriate values, and the amount of coma is suppressed to an amount that can be corrected by other lens groups.
  • the optical system according to the present embodiment can satisfactorily correct spherical aberration by having at least four positive lenses on the image side of the second set.
  • the optical system according to the present embodiment can satisfactorily correct various aberrations such as chromatic aberration by using three or more types of glass materials.
  • the optical system of the present embodiment can further effectively reduce the Petzval sum and correct the field curvature more favorably by satisfying the following conditional expressions (5) to (8).
  • (5) 0.30 ⁇ R1 / f ⁇ 0.80 (6) 0.30 ⁇ R3 / f ⁇ 0.80 (7) -0.80 ⁇ (R1 + R2) / (R1-R2) ⁇ 0.80 (8) -0.80 ⁇ (R3 + R4) / (R3-R4) ⁇ 0.80
  • f focal length of the entire optical system at the time of focusing on an object at infinity
  • R1 radius of curvature of the concave surface on the object side among the facing concave surfaces of the first set
  • R2 of the facing concave surface of the first set
  • the radius of curvature R3 of the concave surface on the image side is the radius of curvature R4 of the concave surface on the object side among the concave surfaces facing each other in the second set.
  • Conditional expression (5) is a conditional expression that defines the ratio between the radius of curvature of the concave surface on the object side and the focal length of the entire optical system among the concave surfaces facing each other in the first set.
  • Conditional expression (6) is a conditional expression that defines the ratio between the radius of curvature of the concave surface on the object side and the focal length of the entire optical system among the opposing concave surfaces of the second set.
  • Conditional expression (7) is a conditional expression for defining the shape factor of the concave surface facing the first set.
  • Conditional expression (8) is a conditional expression for defining the shape factor of the concave surface facing the second set.
  • the effect of the present embodiment can be further ensured.
  • the lower limit of conditional expression (5) it is preferable to set the lower limit of conditional expression (5) to 0.400, more preferably 0.450.
  • the effect of the present embodiment can be further ensured.
  • the lower limit of conditional expression (6) it is preferable to set the lower limit of conditional expression (6) to 0.400, more preferably 0.450.
  • the effect of the present embodiment can be further ensured.
  • the lower limit of conditional expression (7) it is preferable to set the lower limit of conditional expression (7) to -0.700, -0.650, and more preferably -0.600.
  • the effect of the present embodiment can be further ensured.
  • the lower limit of conditional expression (8) it is preferable to set the lower limit of conditional expression (8) to -0.500, -0.300, and more preferably -0.100.
  • the optical system of the present embodiment satisfies the following conditional expression (9). (9) 0.100 ⁇ f / ( ⁇ f1) ⁇ 1.000
  • f focal length of the entire optical system at the time of focusing on an object at infinity
  • f1 all lenses from the lens component closest to the object to the second negative lens component from the object side in the entire optical system
  • Conditional expression (9) represents the combined focal length of all lens components from the lens component closest to the object side to the second negative lens component from the object side in the entire optical system, and the focal length of the entire optical system. It is a conditional expression for defining the ratio with the distance. By satisfying conditional expression (9), it is possible to suppress the deterioration of coma and spherical aberration while effectively reducing the Petzval sum, and as a result, it is possible to satisfactorily correct field curvature.
  • conditional expression (9) of the optical system according to the present embodiment exceeds the upper limit, the Petzval sum cannot be reduced effectively, and it becomes difficult to satisfactorily correct the field curvature. .
  • the upper limit of conditional expression (9) it is preferable to set the upper limit of conditional expression (9) to 0.900, more preferably 0.850.
  • conditional expression (9) of the optical system according to the present embodiment falls below the lower limit, the spherical aberration and the coma become worse.
  • the lower limit of conditional expression (9) it is preferable to set the lower limit of conditional expression (9) to 0.200, more preferably 0.250.
  • the optical system of the present embodiment satisfies the following conditional expression (10). (10) 12.0 ° ⁇ 2 ⁇ ⁇ 40.0 ° However, 2 ⁇ : angle of view of the optical system when focusing on an object at infinity
  • Conditional expression (10) is a condition for defining the optimum value of the angle of view.
  • the optical system of the present embodiment can satisfy the requirement for downsizing of the entire optical system and satisfactory optical performance.
  • the upper limit of conditional expression (10) it is preferable to set the upper limit of conditional expression (10) to 35.0 °. In order to further secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (10) to 30.0 °, 28.0 °, and further preferably 25.0 °. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (10) to 13.0 °. In order to further secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (10) to 15.0 °, 18.0 °, and further preferably 21.0 °.
  • the optical system of the present embodiment satisfies the following conditional expression (11).
  • (11) 0.100 ⁇ bfa / f ⁇ 0.250
  • bfa the air-equivalent distance on the optical axis from the image side lens surface of the lens closest to the image side to the image plane
  • f the focal length of the entire optical system at the time of focusing on an object at infinity
  • conditional expression (11) defines a ratio between the air-equivalent distance on the optical axis from the image-side lens surface of the lens closest to the image side to the image plane and the focal length of the entire optical system. It is. By satisfying conditional expression (11), it is possible to reduce the size of the entire optical system and to satisfy good optical performance.
  • conditional expression (11) of the optical system according to the present embodiment exceeds the upper limit, the entire optical system becomes large in the radial direction due to a large numerical aperture, and it becomes difficult to correct the field curvature.
  • the upper limit of conditional expression (11) it is preferable to set the upper limit of conditional expression (11) to 0.195, 0.185, and more preferably 0.182.
  • conditional expression (11) of the optical system according to the present embodiment falls below the lower limit
  • the diameter of the final lens unit becomes large due to the peripheral light beam, and a strong negative power is applied to reduce the size of the entire optical system. Is required on the rear side, and it is particularly difficult to correct spherical aberration.
  • the lower limit of conditional expression (11) it is preferable to set the lower limit of conditional expression (11) to 0.120, 0.130, and more preferably 0.140.
  • the optical system according to the present embodiment includes a DC group in which the subsequent lens group changes the blur of a defocus area by moving along the optical axis, and the DC group in focusing on an object at infinity.
  • ⁇ DC is the image plane movement coefficient which is the ratio of the image plane movement amount to the movement amount in the optical axis direction.
  • the optical system according to the present embodiment includes a DC group that changes the blur in the defocus area by moving along the optical axis, and satisfies the conditional expression (12), so that undesired coma aberration in the blur is obtained. , Astigmatism, chromatic aberration and the like are minimized, and only spherical aberration is changed. Further, the optical system according to the present embodiment can change the spherical aberration to both positive and negative by moving the DC group in the optical axis direction and changing the distance between the DC group and the lens groups before and after the DC group.
  • the direction of movement of the DC group along the optical axis is such that the direction toward the image side is a positive direction and the direction toward the object side is a negative direction.
  • Conditional expression (12) is a conditional expression that defines the ratio of the moving amount of the image plane to the moving amount of the DC group in the optical axis direction.
  • conditional expression (12) it is possible to reduce the amount of refocusing when the DC group is moved in the optical axis direction to change mainly the spherical aberration. As a result, it is possible to suppress the aberration fluctuation at the time of re-focusing.
  • the image plane movement coefficient ⁇ DC which is the ratio of the amount of movement of the image plane to the amount of movement of the DC group in the optical axis direction when focusing on an object at infinity, is defined by the following equation.
  • ⁇ DC (1 ⁇ DC 2 ) ⁇ ⁇ R 2
  • ⁇ DC lateral magnification of the DC group
  • ⁇ R lateral magnification of the lens group on the image side of the DC group
  • the back focus greatly fluctuates when the DC group is moved in the optical axis direction. It is necessary to move the focus group again greatly. As a result, coma aberration and curvature of field mainly fluctuate due to aberration fluctuations caused by focusing, which is not desirable.
  • the effect of the present embodiment can be made more reliable.
  • the lower limit of conditional expression (12) By setting the lower limit of conditional expression (12) to -0.450, the effect of the present embodiment can be further ensured.
  • optical system of the present embodiment satisfies the following conditional expression (13). (13) 0.700 ⁇ DC ⁇ 1.300 However, ⁇ DC: lateral magnification of the DC group
  • Conditional expression (13) is a conditional expression that defines the lateral magnification of the DC group. By satisfying conditional expression (13), it is possible to suppress excessive enlargement or excessive reduction of aberration of the lens unit on the object side of the DC unit.
  • conditional expression (13) of the optical system according to the present embodiment exceeds the upper limit, the aberration of the lens unit on the object side relative to the DC unit is excessively enlarged, so that coma other than spherical aberration, field curvature, and axial aberration are caused. Large chromatic aberration, chromatic aberration of magnification, and the like also occur largely.
  • the upper limit of conditional expression (13) it is preferable to set the upper limit of conditional expression (13) to 1.200, more preferably 1.150.
  • conditional expression (13) of the optical system according to the present embodiment when the corresponding value of the conditional expression (13) of the optical system according to the present embodiment is below the lower limit, it is difficult to generate a predetermined spherical aberration even if the DC group is moved in the optical axis direction. As a result, it is necessary to move the DC group largely in the optical axis direction, and coma other than spherical aberration, curvature of field, axial chromatic aberration, chromatic aberration of magnification, and the like are largely generated.
  • the lower limit of conditional expression (13) By setting the lower limit of conditional expression (13) to 0.750, the effect of the present embodiment can be further ensured. In order to further secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (13) to 0.800, more preferably 0.850.
  • the optical system according to the present embodiment includes a DC group in which the subsequent lens group changes the blur of a defocus area by moving along the optical axis, and the DC group in focusing on an object at infinity.
  • ⁇ DC the amount of change in spherical aberration in the longitudinal aberration display corresponding to ⁇ DC is ⁇ SA, and the maximum aperture when the DC group does not move in the optical axis direction when an object at infinity is in focus. It is desirable that the following conditional expression (14) is satisfied, where F is the Fin value. (14) 0.300 ⁇
  • Conditional expression (14) defines the ratio of the amount of movement of the DC group when the DC group is moved in the optical axis direction during focusing on an object at infinity to the amount of change in spherical aberration that changes due to this movement of the DC group. Is a conditional expression to be performed.
  • conditional expression (14) By satisfying conditional expression (14), a large change in spherical aberration can be realized even when the DC group moves in a relatively small direction along the optical axis.
  • the way light rays pass through each lens group does not change much compared to when the DC group is not moved, so that it is possible to suppress fluctuations in aberrations other than spherical aberration when the DC group is moved. Become.
  • conditional expression (14) of the optical system according to the present embodiment exceeds the upper limit, when the DC group is moved, coma other than spherical aberration, field curvature, and axial chromatic aberration also occur largely. .
  • the upper limit of conditional expression (14) it is preferable to set the upper limit of conditional expression (14) to 2.000, 1.800, and more preferably 1.500.
  • conditional expression (14) of the optical system according to the present embodiment falls below the lower limit, it is necessary to largely move the DC group in the optical axis direction in order to realize a predetermined change in spherical aberration. .
  • the way light rays pass through each lens group is significantly different from that when the DC group is not moved, so that coma aberration and field curvature in particular vary greatly.
  • the lower limit of conditional expression (14) it is preferable to set the lower limit of conditional expression (14) to 0.400, 0.450, and more preferably 0.500.
  • the optical system according to the present embodiment includes the DC group in which the subsequent lens group changes the blur of the defocus area by moving along the optical axis, and the DC group in focusing on a short-distance object.
  • the amount of movement of the DC group in the optical axis direction as ⁇ DC is the amount of change in spherical aberration in the longitudinal aberration display corresponding to the ⁇ DC is ⁇ SA, and the maximum aperture when the DC group does not move in the optical axis direction when a short-distance object is focused.
  • Is Fmod it is desirable to satisfy the following conditional expression (15). (15) 2.000 ⁇
  • Conditional expression (15) defines the ratio between the amount of movement of the DC group when the DC group is moved in the optical axis direction when a short-distance object is focused and the amount of change in spherical aberration that changes due to this movement of the DC group. Is a conditional expression to be performed.
  • conditional expression (15) a large change in spherical aberration can be realized even with a relatively small movement of the DC group in the optical axis direction.
  • the way light rays pass through each lens group does not change much compared to when the DC group is not moved, so that it is possible to suppress fluctuations in aberrations other than spherical aberration when the DC group is moved. Become.
  • conditional expression (15) of the optical system according to the present embodiment exceeds the upper limit, when the DC group is moved, coma other than spherical aberration, field curvature, and axial chromatic aberration also occur greatly. .
  • the upper limit of conditional expression (15) it is preferable to set the upper limit of conditional expression (15) to 10.000, further preferably 9.000.
  • conditional expression (15) of the optical system according to the present embodiment falls below the lower limit, it is necessary to largely move the DC group in the optical axis direction in order to realize a predetermined change in spherical aberration. .
  • the way light rays pass through each lens group is significantly different from that when the DC group is not moved, so that coma aberration and field curvature in particular vary greatly.
  • the lower limit of conditional expression (15) it is preferable to set the lower limit of conditional expression (15) to 2.700, and more preferably to 3.000.
  • the lens group closest to the image is the DC group.
  • the optical apparatus of the present embodiment has the optical system having the above-described configuration. This makes it possible to satisfactorily correct various aberrations from the in-focus state of an object at infinity to the in-focus state of a close object, and to provide an optical apparatus having a large-diameter optical system suitable for both auto focus and manual focus. Can be realized.
  • the method for manufacturing an optical system according to the present embodiment is a method for manufacturing an optical system including a first lens group having a positive refractive power and a plurality of subsequent lens groups in order from the object side. The distance between the adjacent lens groups is changed, and the first lens group is disposed on the image side with the front lens group having a positive refractive power disposed on the object side with the aperture stop interposed therebetween.
  • a rear lens group having a positive refractive power the front lens group is configured to move to the object side when focusing from an object at infinity to a close object
  • the rear lens unit sets m and n to be positive integers satisfying m ⁇ n, and focuses on an object at infinity at m-th and n-th lens surfaces counted from the most object-side lens surface of the rear lens unit.
  • FIG. 1 is a cross-sectional view of the optical system according to Example 1 upon focusing on an object at infinity. Arrows in FIG. 1 and FIGS. 5, 9, 13, 17, and 21 to be described later indicate the movement trajectories of the respective lens groups when focusing from an object at infinity to an object at a short distance. .
  • the optical system according to this example includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a positive refractive power, and a third lens group having a negative refractive power. G3.
  • the first lens group G1 includes a front lens group G1F having a positive refractive power disposed on the object side and a rear lens group G1R having a positive refractive power disposed on the image side with the aperture stop S interposed therebetween. It is composed of
  • the front lens group G1F includes, in order from the object side, a biconvex positive lens L11, a biconcave negative lens L12, a plano-convex lens L13 having a convex surface facing the object side, and a positive meniscus having a concave surface facing the object side.
  • the rear lens group G1R includes, in order from the object side, a cemented negative lens composed of a biconcave negative lens L112 and a biconvex positive lens L113, a plano-convex lens L114 having a convex surface facing the image side, and a biconvex lens. It comprises a positive lens L115, a cemented positive lens composed of a plano-convex lens L116 with a convex surface facing the image side, and a negative meniscus lens L117 with a concave surface facing the object side.
  • the biconcave negative lens L12 and the positive meniscus lens L14 with the concave surface facing the object side constitute a first lens set C1 with the concave surfaces facing each other.
  • the biconcave negative lens L111 and the biconcave negative lens L112 form a second lens set C2 whose concave surfaces face each other.
  • a plano-convex lens L13 is included between the negative lens L12 and the positive meniscus lens L14, the “set of lenses having concave surfaces facing each other” in the present embodiment includes a lens component having a simple configuration therebetween. Sometimes.
  • the second lens group G2 includes, in order from the object side, a biconvex positive lens L21, a plano-convex lens L22 having a convex surface facing the object side, and a negative meniscus lens L23 having a convex surface facing the object side.
  • the third lens group G3 includes, in order from the object side, a cemented negative lens composed of a biconcave negative lens L31 and a biconvex positive lens L32, a biconvex positive lens L33, and a biconcave negative lens L34. And a negative meniscus lens L35 having a concave surface facing the object side.
  • a filter group FL composed of a low-pass filter or the like is arranged between the third lens group G3 and the image plane I.
  • an image pickup device (not shown) composed of a CCD, a CMOS or the like is arranged on the image plane I.
  • the optical system according to the present embodiment moves the first lens group G1, the second lens group G2, and the third lens group G3 along the optical axis along different trajectories toward the object side, thereby moving the object from an object at infinity. Focusing on a close object. At this time, the front lens group G1F and the rear lens group G1R of the first lens group G1 move integrally to the object side.
  • the optical system according to the present embodiment has a DC group for changing the spherical aberration mainly by moving along the optical axis to the most image side and changing the blur of the defocus area.
  • the second lens group G2 and the third lens group G3 move along the optical axis as a DC group.
  • the second lens group G2 and the third lens group move along the optical axis as a DC group, they move together as one lens group.
  • the optical system according to the present embodiment moves the DC group toward the object from the state where the amount of movement of the DC group in the optical axis direction is 0 (zero), that is, the state where the spherical aberration is satisfactorily corrected, that is, By moving in the direction, the spherical aberration can be changed in a direction in which correction is insufficient.
  • the spherical aberration is changed in a direction in which correction is excessive. be able to.
  • Table 1 below lists values of specifications of the optical system according to the present embodiment.
  • f indicates the focal length
  • BF indicates the back focus, that is, the distance on the optical axis from the lens surface closest to the image side to the image plane I.
  • m is the order of the optical surfaces counted from the object side
  • r is the radius of curvature
  • d is the surface interval (the interval between the nth surface (n is an integer) and the (n + 1) th surface)
  • nd is the d line ( The refractive index with respect to a wavelength of 587.6 nm) and ⁇ d indicate the Abbe number with respect to the d line (with a wavelength of 587.6 nm).
  • CE (1) indicates the values of h (max) and h (min) on the lens surface where the marginal ray height is h (max) and h (min) with respect to conditional expression (1)
  • CE (2) Is the value of h (1), h (max) h and (min) on the lens surface where the marginal ray height is h (1), h (max) and h (min) with respect to conditional expression (2)
  • CE (3) indicates a value corresponding to conditional expression (3) in a negative lens satisfying conditional expression (3).
  • [Aspherical surface data] shows an aspherical surface coefficient and a conical constant when the shape of the aspherical surface shown in [surface data] is represented by the following equation.
  • x (h 2 / r) / [1+ ⁇ 1- ⁇ (h / r) 2 ⁇ 1/2 ] + A4h 4 + A6h 6 + A8h 8 + A10h 10 + A12h 12 + A14h 14
  • h is the height in the direction perpendicular to the optical axis
  • x is the distance along the optical axis from the tangent plane of the vertex of the aspheric surface at the height h to the aspheric surface
  • ⁇ is the conic constant
  • A4, A6, A8, A10, A12, A14 are aspherical coefficients
  • r is a paraxial radius of curvature which is the radius of curvature of the reference spherical surface.
  • en (n: an integer) indicates “ ⁇ 10 ⁇ n ”, and for example, “1.234e-05” indicates “1.234 ⁇ 10 ⁇ 5 ”.
  • the second-order aspheric coefficient A2 is 0, and the description is omitted.
  • f is the focal length of the entire optical system
  • FNo is the F number
  • ⁇ is the half angle of view (unit is “°”)
  • Y is the maximum image height
  • TL is the optical system according to the present embodiment.
  • the total length that is, the distance on the optical axis from the first surface to the image plane I, and the BF (air conversion length) indicate the BF obtained by converting the thickness of the filter group FL into air.
  • Finf indicates the F value of the maximum aperture when the DC group does not move in the optical axis direction during focusing on an object at infinity, that is, when the amount of movement of the DC group in the optical axis direction is 0 (zero)
  • Fmod indicates the F value of the maximum aperture when the DC group does not move in the optical axis direction when a short-distance object is focused, that is, when the amount of movement of the DC group in the optical axis direction is 0 (zero).
  • D0 is the distance from the object to the lens surface closest to the object
  • ⁇ is the closest photographing magnification
  • f is the focal length of the entire optical system
  • Dn (n is an integer) is the nth surface and the (n + 1) th.
  • INF indicates the time of focusing on an object at infinity
  • CLO indicates the time of focusing on an object at a short distance
  • INFDC (-) indicates that the object is in focus at infinity and the DC group has moved to the object side
  • INFDC (+) indicates that the object has focus at infinity and the DC group has moved to the image plane I side.
  • CLODC (+) is in focus on a short-distance object and the DC group has moved to the object side
  • CLODC (+) is in focus on a short-distance object and the DC group has moved to the image plane I side
  • [Lens group data] indicates the starting surface number ST and the focal length f of each lens group.
  • [Conditional expression corresponding value] shows the corresponding value of each conditional expression.
  • the unit of the focal length f, the radius of curvature r and other lengths shown in Table 1 is generally “mm”.
  • the optical system is not limited to this, since the same optical performance can be obtained even if the optical system is proportionally enlarged or proportionally reduced. Note that the reference numerals in Table 1 described above are used in the same manner in the tables of each embodiment described later.
  • FIGS. 2A and 2B are graphs showing various aberrations when the DC group is not moved when the optical system according to the first example is focused on an object at infinity and when focused on a short-distance object, respectively.
  • FIGS. 3A and 3B are graphs showing various aberrations when the DC unit moves to the object side and the DC unit moves to the image side when the optical system according to the first example is focused on an object at infinity.
  • FIGS. 4A and 4B are graphs showing various aberrations in a state where the DC group moves to the object side and a state where the DC group moves to the image side when the optical system according to the first example is focused on a short-distance object. is there.
  • FNO indicates an F number
  • Y indicates an image height
  • NA indicates a numerical aperture
  • the spherical aberration diagram shows the value of the F-number FNO or the numerical aperture NA corresponding to the maximum aperture
  • the astigmatism diagram and the distortion diagram show the maximum value of the image height Y
  • the lateral aberration diagram shows the maximum value of each image height. Indicates a value.
  • d indicates an aberration curve at the d-line (wavelength 587.6 nm)
  • g indicates an aberration curve at the g-line (wavelength 435.8 nm)
  • those without descriptions indicate aberration curves at the d line.
  • a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane.
  • the lateral aberration diagram shows lateral aberration (coma aberration) at each image height Y. Note that the same reference numerals as in the present embodiment are used in the aberration diagrams of the embodiments described later.
  • the optical system according to the present embodiment has excellent imaging performance by well correcting various aberrations from the time of focusing on an object at infinity to the time of focusing on a close object. You can see that it is doing.
  • the optical system according to the present embodiment favorably suppresses the fluctuation of other aberrations while mainly changing only spherical aberration at the time of focusing on an object at infinity. You can see that there is.
  • the optical system according to the present embodiment favorably suppresses the fluctuation of other aberrations while mainly changing only spherical aberration at the time of focusing on a short-distance object. You can see that there is.
  • FIG. 5 is a cross-sectional view of the optical system according to Example 2 upon focusing on an object at infinity.
  • the optical system according to this example includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a positive refractive power, and a third lens group having a negative refractive power. G3.
  • the first lens group G1 includes a front lens group G1F having a positive refractive power disposed on the object side and a rear lens group G1R having a positive refractive power disposed on the image side with the aperture stop S interposed therebetween. It is composed of
  • the front lens group G1F includes, in order from the object side, a biconvex positive lens L11, a biconcave negative lens L12, a biconvex positive lens L13, and a positive meniscus lens L14 having a concave surface facing the object side.
  • a cemented negative lens with a biconcave negative lens L15, a biconvex positive lens L16, a positive meniscus lens L17 with a concave surface facing the object side, a plano-convex lens L18 with a convex surface facing the image side, and a It comprises a cemented negative lens with a concave meniscus lens L19 and a cemented negative lens with a biconvex positive lens L110 and a biconcave negative lens L111.
  • the rear lens group G1R includes, in order from the object side, a cemented negative lens composed of a biconcave negative lens L112 and a biconvex positive lens L113, a plano-convex lens L114 having a convex surface facing the image side, and a biconvex lens. It comprises a positive lens L115, a cemented positive lens composed of a plano-convex lens L116 with a convex surface facing the image side, and a negative meniscus lens L117 with a concave surface facing the object side.
  • the biconcave negative lens L12 and the positive meniscus lens L14 with the concave surface facing the object side constitute a first lens set C1 with the concave surfaces facing each other.
  • the biconcave negative lens L111 and the biconcave negative lens L112 form a second lens set C2 whose concave surfaces face each other.
  • a biconvex positive lens L13 is included between the negative lens L12 and the positive meniscus lens L14.
  • the second lens group G2 includes, in order from the object side, a biconvex positive lens L21, a plano-convex lens L22 having a convex surface facing the object side, and a negative meniscus lens L23 having a convex surface facing the object side.
  • the third lens group G3 includes, in order from the object side, a cemented negative lens composed of a biconcave negative lens L31 and a biconvex positive lens L32, a biconvex positive lens L33, and a biconcave negative lens L34. And a negative meniscus lens L35 having a concave surface facing the object side.
  • a filter group FL composed of a low-pass filter or the like is arranged between the third lens group G3 and the image plane I.
  • an image pickup device (not shown) composed of a CCD, a CMOS or the like is arranged on the image plane I.
  • the optical system moves the first lens group G1, the second lens group G2, and the third lens group along the optical axis along different trajectories toward the object side, thereby moving the first lens group G1, the second lens group G2, and the third lens group G from an object at infinity. Focusing on a distance object. At this time, the front lens group G1F and the rear lens group G1R of the first lens group G1 move integrally to the object side.
  • the optical system according to the present embodiment has a DC group for changing the spherical aberration mainly by moving along the optical axis to the most image side and changing the blur of the defocus area.
  • the second lens group G2 and the third lens group G3 move along the optical axis as a DC group.
  • the second lens group G2 and the third lens group move along the optical axis as a DC group, they move together as one lens group.
  • the optical system according to the present embodiment moves the DC group toward the object from the state where the amount of movement of the DC group in the optical axis direction is 0 (zero), that is, the state where the spherical aberration is satisfactorily corrected, that is, By moving in the direction, the spherical aberration can be changed in a direction in which correction is insufficient.
  • the spherical aberration is changed in a direction in which correction is excessive. be able to.
  • Table 2 shows values of specifications of the optical system according to the present example.
  • FIGS. 8A and 8B are graphs showing various aberrations when the optical system according to the second embodiment focuses on a short-distance object, with the DC group moved to the object side and the DC group moved to the image side. is there.
  • the optical system according to the present example has excellent imaging performance by favorably correcting various aberrations from when focusing on an object at infinity to when focusing on a close object. You can see that it is doing.
  • the optical system according to the present embodiment favorably suppresses the fluctuation of other aberrations while mainly changing only spherical aberration at the time of focusing on an object at infinity. You can see that there is.
  • the optical system according to the present embodiment favorably suppresses fluctuations of other aberrations while mainly changing only spherical aberration at the time of focusing on a short-distance object. You can see that there is.
  • FIG. 9 is a cross-sectional view of the optical system according to Example 3 upon focusing on an object at infinity.
  • the optical system according to this example includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a positive refractive power, and a third lens group having a negative refractive power. G3.
  • the first lens group G1 includes a front lens group G1F having a positive refractive power disposed on the object side and a rear lens group G1R having a positive refractive power disposed on the image side with the aperture stop S interposed therebetween. It is composed of
  • the front lens group G1F includes, in order from the object side, a biconvex positive lens L11, a biconcave negative lens L12, a biconvex positive lens L13, and a positive meniscus lens L14 having a concave surface facing the object side.
  • the rear lens group G1R includes, in order from the object side, a first partial group G1R1 having a negative refractive power and a second partial group G1R2 having a positive refractive power.
  • the first subgroup G1R1 includes, in order from the object side, a cemented negative lens of a biconcave negative lens L112 and a biconvex positive lens L113, and a positive meniscus lens L114 having a concave surface facing the object side.
  • the second subgroup G1R2 includes, in order from the object side, a biconvex positive lens L115, and a cemented negative lens formed by a biconvex positive lens L116 and a biconcave negative lens L117.
  • the biconcave negative lens L12 and the positive meniscus lens L14 with the concave surface facing the object side constitute a first lens set C1 with the concave surfaces facing each other.
  • the biconcave negative lens L111 and the biconcave negative lens L112 form a second lens set C2 whose concave surfaces face each other.
  • a biconvex positive lens L13 is included between the negative lens L12 and the positive meniscus lens L14.
  • the second lens group G2 includes, in order from the object side, a biconvex positive lens L21, a biconvex positive lens L22, and a negative meniscus lens L23 having a convex surface facing the object side.
  • the third lens group G3 includes, in order from the object side, a cemented positive lens composed of a biconcave negative lens L31 and a biconvex positive lens L32, a biconvex positive lens L33, and a biconcave negative lens L34. And a negative meniscus lens L35 having a concave surface facing the object side.
  • a filter group FL composed of a low-pass filter or the like is arranged between the third lens group G3 and the image plane I.
  • an image pickup device (not shown) composed of a CCD, a CMOS or the like is arranged on the image plane I.
  • the optical system according to this example includes a front lens group G1F, a first partial group G1R1 of the rear lens group G1R, a second partial group G1R2 of the rear lens group G1R, a second lens group G2, and a third lens group.
  • the optical system according to the present embodiment has a DC group for changing the spherical aberration mainly by moving along the optical axis to the most image side and changing the blur of the defocus area.
  • the second lens group G2 and the third lens group G3 move along the optical axis as a DC group.
  • the second lens group G2 and the third lens group move along the optical axis as a DC group, they move together as one lens group.
  • the optical system according to the present embodiment moves the DC group toward the object from the state where the amount of movement of the DC group in the optical axis direction is 0 (zero), that is, the state where the spherical aberration is satisfactorily corrected, that is, By moving in the direction, the spherical aberration can be changed in a direction in which correction is insufficient.
  • the spherical aberration is changed in a direction in which correction is excessive. be able to.
  • Table 3 shows values of specifications of the optical system according to the present example.
  • FIGS. 10A and 10B are graphs showing various aberrations of the optical system according to Example 3 when focusing on an object at infinity and when focusing on a short-distance object, respectively.
  • FIGS. 11A and 11B are graphs showing various aberrations when the DC unit moves to the object side and the DC unit moves to the image side when the optical system according to Example 3 is focused on an object at infinity.
  • FIGS. 12A and 12B are graphs showing various aberrations when the optical system according to Example 3 focuses on a short-distance object, with the DC group moved to the object side and the DC group moved to the image side. is there.
  • the optical system according to the present embodiment has excellent imaging performance by satisfactorily correcting various aberrations from when focusing on an object at infinity to when focusing on a close object. You can see that it is doing.
  • the optical system according to the present embodiment favorably suppresses fluctuations of other aberrations while mainly changing only spherical aberration at the time of focusing on an object at infinity. You can see that there is.
  • the optical system according to the present embodiment favorably suppresses fluctuations of other aberrations while mainly changing only spherical aberration during focusing on a short-distance object. You can see that there is.
  • FIG. 13 is a sectional view of the optical system according to Example 4 when focusing on an object at infinity.
  • the optical system according to this embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens group having a negative refractive power. G3.
  • the first lens group G1 includes a front lens group G1F having a positive refractive power disposed on the object side and a rear lens group G1R having a positive refractive power disposed on the image side with the aperture stop S interposed therebetween. It is composed of
  • the front lens group G1F includes, in order from the object side, a biconvex positive lens L11, a negative meniscus lens L12 having a convex surface facing the object side, a positive meniscus lens L13 having a convex surface facing the object side, and a concave surface facing the object side.
  • the rear lens group G1R includes, in order from the object side, a cemented negative lens composed of a biconcave negative lens L110 and a biconvex positive lens LL111; a positive meniscus lens L112 having a concave surface facing the object side; And a cemented positive lens formed by a biconvex positive lens LL114 and a biconcave negative lens L115.
  • the negative meniscus lens L12 having a convex surface facing the object side and the positive meniscus lens L14 having a concave surface facing the object side constitute a first lens set C1 whose concave surfaces face each other.
  • the biconcave negative lens L19 and the biconcave negative lens L110 form a second lens set C2 whose concave surfaces face each other.
  • a positive meniscus lens L13 is included between the negative meniscus lens L12 and the positive meniscus lens L14.
  • the second lens group G2 includes, in order from the object side, a biconvex positive lens L21, a negative meniscus lens L22 having a convex surface facing the object side, a negative meniscus lens L23 having a convex surface facing the object side, and a biconvex lens. And a cemented positive lens with the positive lens L24.
  • the third lens group G3 includes, in order from the object side, a cemented negative lens composed of a biconcave negative lens L31 and a biconvex positive lens L32, a biconvex positive lens L33, and a biconcave negative lens L34. And a negative meniscus lens L35 having a concave surface facing the object side.
  • a filter group FL composed of a low-pass filter or the like is arranged between the third lens group G3 and the image plane I.
  • an image pickup device (not shown) composed of a CCD, a CMOS or the like is arranged on the image plane I.
  • the optical system moves the first lens group G1, the second lens group G2, and the third lens group along the optical axis along different trajectories toward the object side, thereby moving the first lens group G1, the second lens group G2, and the third lens group G from an object at infinity. Focusing on a distance object.
  • the optical system according to the present embodiment has a DC group for changing the spherical aberration mainly by moving along the optical axis to the most image side and changing the blur of the defocus area.
  • the second lens group G2 and the third lens group G3 move along the optical axis as a DC group.
  • the second lens group G2 and the third lens group move along the optical axis as a DC group, they move together as one lens group.
  • the optical system according to the present embodiment moves the DC group toward the object from the state where the amount of movement of the DC group in the optical axis direction is 0 (zero), that is, the state where the spherical aberration is satisfactorily corrected, that is, By moving in the direction, the spherical aberration can be changed in a direction in which correction is insufficient.
  • the spherical aberration is changed in a direction in which correction is excessive. be able to.
  • Table 4 shows values of specifications of the optical system according to the present example.
  • FIGS. 14A and 14B are graphs showing various aberrations of the optical system according to Example 4 when focusing on an object at infinity and when focusing on a close object.
  • FIGS. 15A and 15B are graphs showing various aberrations when the DC unit moves to the object side and the DC unit moves to the image side when the optical system according to Example 4 is focused on an object at infinity.
  • . 16A and 16B are graphs showing various aberrations in a state where the DC unit moves to the object side and a state where the DC unit moves to the image side when the optical system according to the fourth example is in focus on a short-distance object. is there.
  • the optical system according to the present embodiment has excellent imaging performance by well correcting various aberrations from the time of focusing on an object at infinity to the time of focusing on a close object. You can see that it is doing.
  • the optical system according to the present embodiment favorably suppresses fluctuations of other aberrations while mainly changing only spherical aberration at the time of focusing on an object at infinity. You can see that there is.
  • the optical system according to the present embodiment favorably suppresses the fluctuation of other aberrations while mainly changing only the spherical aberration at the time of focusing on a short-distance object. You can see that there is.
  • FIG. 17 is a cross-sectional view of the optical system according to Example 5 upon focusing on an object at infinity.
  • the optical system according to this example includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a positive refractive power, and a third lens group having a negative refractive power. G3.
  • the first lens group G1 includes a front lens group G1F having a positive refractive power disposed on the object side and a rear lens group G1R having a positive refractive power disposed on the image side with the aperture stop S interposed therebetween. It is composed of
  • the front lens group G1F includes, in order from the object side, a biconvex positive lens L11, a negative meniscus lens L12 having a convex surface facing the object side, a positive meniscus lens L13 having a convex surface facing the object side, and a concave surface facing the object side.
  • a biconvex positive lens L11 a biconvex positive lens L11
  • a negative meniscus lens L12 having a convex surface facing the object side
  • a positive meniscus lens L13 having a convex surface facing the object side
  • a concave surface facing the object side a concave surface facing the object side.
  • the rear lens group G1R includes, in order from the object side, a cemented negative lens composed of a biconcave negative lens L19 and a biconvex positive lens LL110; a positive meniscus lens L111 having a concave surface facing the object side; LL112, a biconvex positive lens LL113, and a negative meniscus lens L114 having a concave surface facing the object side.
  • the negative meniscus lens L12 having a convex surface facing the object side and the positive meniscus lens L14 having a concave surface facing the object side constitute a first lens set C1 whose concave surfaces face each other.
  • the biconcave negative lens L18 and the biconcave negative lens L19 constitute a second lens set C2 whose concave surfaces face each other.
  • a positive meniscus lens L13 is included between the negative meniscus lens L12 and the positive meniscus lens L14.
  • the second lens group G2 includes, in order from the object side, a biconvex positive lens L21, a negative meniscus lens L22 having a convex surface facing the object side, and a positive meniscus lens L23 having a concave surface facing the object side.
  • the third lens group G3 includes, in order from the object side, a cemented negative lens composed of a biconcave negative lens L31 and a biconvex positive lens L32, a biconvex positive lens L33, and a biconcave negative lens L34. And a negative meniscus lens L35 having a concave surface facing the object side.
  • a filter group FL composed of a low-pass filter or the like is arranged between the third lens group G3 and the image plane I.
  • an image pickup device (not shown) composed of a CCD, a CMOS or the like is arranged on the image plane I.
  • the optical system moves the first lens group G1, the second lens group G2, and the third lens group along the optical axis along different trajectories toward the object side, thereby moving the first lens group G1, the second lens group G2, and the third lens group G from an object at infinity. Focusing on a distance object.
  • the optical system according to the present embodiment has a DC group for changing the spherical aberration mainly by moving along the optical axis closest to the image side and changing the blurring of the defocus area.
  • the second lens group G2 and the third lens group G3 move along the optical axis as a DC group.
  • the second lens group G2 and the third lens group move along the optical axis as a DC group, they move together as one lens group.
  • the optical system according to the present embodiment moves the DC group toward the object from the state where the amount of movement of the DC group in the optical axis direction is 0 (zero), that is, the state where the spherical aberration is satisfactorily corrected, that is, By moving in the direction, the spherical aberration can be changed in a direction in which correction is insufficient.
  • the spherical aberration is changed in a direction in which correction is excessive. be able to.
  • Table 5 shows values of specifications of the optical system according to the present example.
  • FIGS. 19A and 19B are graphs showing various aberrations when the DC unit moves to the object side and the DC unit moves to the image side when the optical system according to Example 5 is focused on an object at infinity.
  • 20A and 20B are graphs showing various aberrations in a state where the DC group moves to the object side and a state where the DC group moves to the image side when the optical system according to Example 5 is focused on a short-distance object. is there.
  • the optical system according to the present embodiment has excellent imaging performance by favorably correcting various aberrations from the time of focusing on an object at infinity to the time of focusing on a close object. You can see that it is doing.
  • the optical system according to the present embodiment favorably suppresses fluctuations of other aberrations while mainly changing only spherical aberration at the time of focusing on an object at infinity. You can see that there is.
  • the optical system according to the present embodiment favorably suppresses fluctuations of other aberrations while mainly changing only spherical aberration during focusing on a short-distance object. You can see that there is.
  • FIG. 21 is a sectional view of the optical system according to Example 6 upon focusing on an object at infinity.
  • the optical system according to this embodiment includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens group having a negative refractive power. G3.
  • the first lens group G1 includes a front lens group G1F having a positive refractive power disposed on the object side and a rear lens group G1R having a positive refractive power disposed on the image side with the aperture stop S interposed therebetween. It is composed of
  • the front lens group G1F includes, in order from the object side, a biconvex positive lens L11, a negative meniscus lens L12 having a convex surface facing the object side, a positive meniscus lens L13 having a convex surface facing the object side, and a concave surface facing the object side.
  • the rear lens group G1R includes, in order from the object side, a cemented negative lens composed of a biconcave negative lens L110 and a biconvex positive lens LL111; a positive meniscus lens L112 having a concave surface facing the object side; And a cemented negative lens of a positive lens LL114 having a biconvex shape and a negative meniscus lens L115 having a concave surface facing the object side.
  • the negative meniscus lens L12 having a convex surface facing the object side and the positive meniscus lens L14 having a concave surface facing the object side constitute a first lens set C1 whose concave surfaces face each other.
  • the biconcave negative lens L19 and the biconcave negative lens L110 form a second lens set C2 whose concave surfaces face each other.
  • a positive meniscus lens L13 is included between the negative meniscus lens L12 and the positive meniscus lens L14.
  • the second lens group G2 includes, in order from the object side, a biconvex positive lens L21, a negative meniscus lens L22 having a convex surface facing the object side, a biconcave negative lens L23, and a biconvex positive lens L24. And a cemented positive lens.
  • the third lens group G3 includes, in order from the object side, a cemented positive lens composed of a biconcave negative lens L31 and a biconvex positive lens L32, a biconvex positive lens L33, and a biconcave negative lens L34. And a negative meniscus lens L35 having a concave surface facing the object side.
  • a filter group FL composed of a low-pass filter or the like is arranged between the third lens group G3 and the image plane I.
  • an image pickup device (not shown) composed of a CCD, a CMOS or the like is arranged on the image plane I.
  • the optical system moves the first lens group G1, the second lens group G2, and the third lens group along the optical axis along different trajectories toward the object side, thereby moving the first lens group G1, the second lens group G2, and the third lens group G from an object at infinity. Focusing on a distance object.
  • the optical system according to the present embodiment has a DC group for changing the spherical aberration mainly by moving along the optical axis to the most image side and changing the blur of the defocus area.
  • the second lens group G2 and the third lens group G3 move along the optical axis as a DC group.
  • the second lens group G2 and the third lens group move along the optical axis as a DC group, they move together as one lens group.
  • the optical system according to the present embodiment moves the DC group toward the object from the state where the amount of movement of the DC group in the optical axis direction is 0 (zero), that is, the state where the spherical aberration is satisfactorily corrected, that is, By moving in the direction, the spherical aberration can be changed in a direction in which correction is insufficient.
  • the spherical aberration is changed in a direction in which correction is excessive. be able to.
  • Table 6 shows values of specifications of the optical system according to the present example.
  • FIGS. 22A and 22B are aberration diagrams of the optical system according to Example 6 upon focusing on an object at infinity and upon focusing on a close object, respectively.
  • FIGS. 23A and 23B are aberration diagrams of the optical system according to Example 6 when the DC unit is moved to the object side and when the DC unit is moved to the image side when focusing on an object at infinity.
  • FIGS. 24A and 24B are graphs showing various aberrations in a state where the DC unit moves to the object side and a state where the DC unit moves to the image side when the optical system according to Example 6 is focused on a short-distance object. is there.
  • the optical system according to the present example has excellent imaging performance by well correcting various aberrations from the time of focusing on an object at infinity to the time of focusing on a close object. You can see that it is doing.
  • the optical system according to the present embodiment favorably suppresses fluctuations of other aberrations while mainly changing only spherical aberration at the time of focusing on an object at infinity. You can see that there is.
  • the optical system according to the present embodiment favorably suppresses fluctuations of other aberrations while mainly changing only spherical aberration at the time of focusing on a short-distance object. You can see that there is.
  • each of the above embodiments it is possible to satisfactorily correct various aberrations from an in-focus state of an object at infinity to an in-focus state of a close object, and a large-diameter optical system suitable for both auto focus and manual focus. Can be realized.
  • the spherical aberration is mainly changed according to the user's intention to maintain sharp depiction of the focused object while maintaining the sharpness of the image.
  • the bokeh of the background outside the depth of field or the foreground outside the depth of field can be changed.
  • the present embodiment is not limited to this, and an optical system having another group configuration (for example, four groups) can be configured. .
  • an optical system having another group configuration for example, four groups
  • a configuration in which a lens or a lens group is added to the most object side or the most image side of the optical system of each of the above embodiments may be used.
  • a lens or a lens group may be added between adjacent lens groups.
  • the lens group may include at least one lens.
  • each lens group is a focusing lens group.
  • a focusing lens group can also be applied to autofocus, and is also suitable for driving by a motor for autofocus, for example, an ultrasonic motor, a stepping motor, a VCM motor, or the like.
  • the whole or a part of any of the lens groups is moved so as to include a component in a direction perpendicular to the optical axis as an image stabilizing group, or a surface including the optical axis.
  • a configuration in which vibration is prevented by rotating (swinging) inward is also possible.
  • the aperture stop of the optical system of each of the above embodiments may be configured so that a role is substituted by a lens frame without providing a member as the aperture stop.
  • the lens surface of the lens constituting the optical system of each of the above embodiments may be a spherical surface, a flat surface, or an aspheric surface.
  • the lens surface is a spherical surface or a flat surface, lens processing and assembly adjustment are facilitated, and deterioration of optical performance due to errors in lens processing and assembly adjustment can be prevented. Further, even when the image plane is displaced, it is preferable because the deteriorating performance is small.
  • the lens surface is an aspherical surface
  • any of an aspherical surface by grinding, a glass molded aspherical surface obtained by molding glass into an aspherical shape with a mold, or a composite aspherical surface formed by forming a resin provided on the glass surface into an aspherical shape is used.
  • the lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.
  • GRIN lens gradient index lens
  • an antireflection film having a high transmittance in a wide wavelength range may be provided on the lens surface of the lens constituting the optical system of each of the above embodiments. Thereby, flare and ghost can be reduced, and high optical performance with high contrast can be achieved.
  • FIG. 25 is a diagram illustrating a configuration of a camera including the optical system according to the present embodiment.
  • the camera 1 is an interchangeable lensless mirrorless camera including the optical system according to the first embodiment as the taking lens 2.
  • the camera 1 In the camera 1, light from an unillustrated object (subject) is condensed by a photographing lens 2 and passes through an unillustrated OLPF (Optical Low Pass Filter) on an imaging surface of an imaging unit 3. To form a subject image. Then, the subject image is photoelectrically converted by a photoelectric conversion element provided in the imaging unit 3 to generate an image of the subject. This image is displayed on an EVF (Electronic view finder) 4 provided in the camera 1. This allows the photographer to observe the subject via the EVF 4. When a release button (not shown) is pressed by the photographer, the image of the subject generated by the imaging unit 3 is stored in a memory (not shown). In this way, the photographer can photograph the subject with the camera 1.
  • OLPF Optical Low Pass Filter
  • the optical system according to the first embodiment mounted on the camera 1 as the photographing lens 2 satisfactorily corrects various aberrations from the in-focus object state to the close-distance object focus state as described above. It is a large-diameter optical system suitable for both auto focus and manual focus. That is, the camera 1 can satisfactorily correct various aberrations from the in-focus state of an object at infinity to the in-focus state of a close object, and can achieve performance suitable for both auto focus and manual focus. . It should be noted that the same effects as those of the camera 1 can be obtained even if a camera in which the optical system according to the second to sixth embodiments is mounted as the taking lens 2 is configured. Further, even when the optical system according to each of the above-described embodiments is mounted on a single-lens reflex camera having a quick return mirror and observing a subject with a finder optical system, the same effects as those of the camera 1 can be obtained.
  • FIG. 26 is a flowchart showing an outline of the method of manufacturing an optical system according to the present embodiment.
  • the method for manufacturing an optical system according to the present embodiment shown in FIG. 26 is a method for manufacturing an optical system including a first lens group having a positive refractive power and a plurality of subsequent lens groups in order from the object side. Steps S1 to S4.
  • Step S1 At the time of focusing, the distance between the adjacent lens groups is changed.
  • Step S4 The rear lens group sets m and n to be positive integers satisfying m ⁇ n, and counts m and n on the m-th and n-th lens surfaces counted from the most object side lens surface of the rear lens group.
  • the marginal ray heights at the time of focusing on an object at infinity are h (m) and h (n)
  • Is defined as h (max) and the lowest h (n) is defined as h (min), so that the following conditional expression (1) is satisfied.
  • various aberrations can be favorably corrected from the in-focus state of an object at infinity to the in-focus state of an object at a close distance.
  • a suitable large-diameter optical system can be manufactured.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Lenses (AREA)

Abstract

Il est possible de fournir une microlentille à grande ouverture capable de corriger de manière excellente diverses aberrations et de commander le flou d'une image défocalisée, étant donné que la microlentille comprend un premier groupe de lentilles ayant une réfringence positive et une pluralité de groupes de lentilles ultérieurs séquentiellement depuis le côté objet, l'intervalle entre les groupes de lentilles adjacents variant pendant la mise au point, le premier groupe de lentilles comprend un groupe de lentilles avant ayant une réfringence positive et étant disposé sur le côté objet et comprend, à travers un diaphragme d'ouverture, un groupe de lentilles arrière ayant une réfringence positive étant disposé sur le côté image, le groupe de lentilles avant se déplaçant vers le côté objet pendant la mise au point d'un objet à distance infinie à un objet à distance proche, et le groupe de lentilles arrière satisfaisant une expression conditionnelle prescrite.
PCT/JP2019/030872 2018-08-24 2019-08-06 Système optique, dispositif optique, et procédé de fabrication d'un système optique WO2020039912A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113835209A (zh) * 2021-11-19 2021-12-24 中导光电设备股份有限公司 一种大视场duv物镜

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56107210A (en) * 1980-01-31 1981-08-26 Nippon Kogaku Kk <Nikon> Lens system permitting short-distance photographing
JPH09218346A (ja) * 1996-02-08 1997-08-19 Minolta Co Ltd 光学系
JPH11281892A (ja) * 1998-03-27 1999-10-15 Canon Inc フローティングを利用した撮影レンズ
JP2000089113A (ja) * 1998-09-07 2000-03-31 Canon Inc フローティングを利用した撮影レンズ
JP2010145830A (ja) * 2008-12-19 2010-07-01 Canon Inc 撮影レンズ及びそれを有する撮像装置
JP2012185263A (ja) * 2011-03-04 2012-09-27 Nikon Corp 撮影レンズ、この撮影レンズを有する光学機器、及び、撮影レンズの製造方法
JP2013104994A (ja) * 2011-11-14 2013-05-30 Sigma Corp 防振機能を有するインナーフォーカス式大口径望遠マクロレンズ
JP2013238827A (ja) * 2012-05-17 2013-11-28 Canon Inc 光学系及びそれを有する撮像装置
JP2013250294A (ja) * 2012-05-30 2013-12-12 Nikon Corp 撮影レンズ、光学機器、および撮影レンズの製造方法

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56107210A (en) * 1980-01-31 1981-08-26 Nippon Kogaku Kk <Nikon> Lens system permitting short-distance photographing
JPH09218346A (ja) * 1996-02-08 1997-08-19 Minolta Co Ltd 光学系
JPH11281892A (ja) * 1998-03-27 1999-10-15 Canon Inc フローティングを利用した撮影レンズ
JP2000089113A (ja) * 1998-09-07 2000-03-31 Canon Inc フローティングを利用した撮影レンズ
JP2010145830A (ja) * 2008-12-19 2010-07-01 Canon Inc 撮影レンズ及びそれを有する撮像装置
JP2012185263A (ja) * 2011-03-04 2012-09-27 Nikon Corp 撮影レンズ、この撮影レンズを有する光学機器、及び、撮影レンズの製造方法
JP2013104994A (ja) * 2011-11-14 2013-05-30 Sigma Corp 防振機能を有するインナーフォーカス式大口径望遠マクロレンズ
JP2013238827A (ja) * 2012-05-17 2013-11-28 Canon Inc 光学系及びそれを有する撮像装置
JP2013250294A (ja) * 2012-05-30 2013-12-12 Nikon Corp 撮影レンズ、光学機器、および撮影レンズの製造方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113835209A (zh) * 2021-11-19 2021-12-24 中导光电设备股份有限公司 一种大视场duv物镜
CN113835209B (zh) * 2021-11-19 2024-04-26 中导光电设备股份有限公司 一种大视场duv物镜

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