WO2016114081A1 - Optical system for observation and imaging device provided with same - Google Patents

Optical system for observation and imaging device provided with same Download PDF

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Publication number
WO2016114081A1
WO2016114081A1 PCT/JP2015/085835 JP2015085835W WO2016114081A1 WO 2016114081 A1 WO2016114081 A1 WO 2016114081A1 JP 2015085835 W JP2015085835 W JP 2015085835W WO 2016114081 A1 WO2016114081 A1 WO 2016114081A1
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Prior art keywords
optical system
lens
observation optical
imaging
image
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PCT/JP2015/085835
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French (fr)
Japanese (ja)
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靖彦 帯金
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株式会社タムロン
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/18—Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B23/00—Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
    • G02B23/24—Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes
    • G02B23/26—Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes using light guides

Definitions

  • the present invention relates to an observation optical system and an image pickup apparatus including the observation optical system.
  • the reduction in the diameter of the objective lens in the above-described conventional observation optical system and an image pickup apparatus including the same has the following three problems with respect to higher resolution.
  • the resolution limit of the optical system is lowered due to the diffraction limit, resulting in a problem that high resolution image quality cannot be achieved.
  • the spatial intermediate image formed by the objective lens is small. For example, it is conceivable to reduce the diameter of the entire portion inserted into a predetermined region by reducing the diameter of the objective lens and the relay lens system and reducing the spatial intermediate imaging accordingly.
  • the image formation is relayed in the order of the objective lens, the single or plural relay lens systems, the eyepiece lens, the imaging lens, and the imaging element in this order from the object side.
  • the single or plural relay lens systems make it possible to pick up an image close to the subject by making the length of the small diameter portion longer than a certain length.
  • the resolution is inevitably deteriorated between the spatial intermediate images, and there is a problem that the desired high-resolution image quality cannot be finally obtained.
  • N is the relay frequency of the relay optical system
  • the relay optical There has been proposed an observation objective lens in which an observation optical system other than the system has (N + 4) or more refractive surfaces having negative refractive power in contact with air (see, for example, Patent Document 1).
  • a first group having negative refractive power, a second group having positive refractive power, a third group having negative refractive power, and a first group having positive refractive power And satisfying a predetermined conditional expression relating to the focal length of the entire system at the wide end, the focal length of the fourth group, the magnification of the third group at the wide end and the tele end, and the third group as the optical axis has been proposed (see, for example, Patent Literature 2).
  • Patent Document 1 Since the observation objective lens proposed by Patent Document 1 has a plurality of relay lenses, as the number of spatial intermediate imaging increases, the resolution decreases due to the influence of manufacturing errors and the like, resulting in higher resolution. Is difficult. In addition, since the loss of light amount due to the glass in the long optical path is large, there is a problem that the amount of light reaching the image sensor is reduced and a bright and clear image cannot be formed.
  • An object of the present invention is to provide an observation optical system and an imaging apparatus including the observation optical system.
  • the first invention includes an objective lens and an imaging lens in order from the object side, and includes a focus group that moves and focuses in the optical axis direction according to a change in the object distance in the imaging lens,
  • An objective lens is an observation optical system characterized in that a subject image is reduced and incident on a spatial intermediate imaging plane, and the imaging lens enlarges the spatial intermediate imaging and re-images it on an image sensor. is there.
  • the second invention includes an objective lens and an imaging lens in order from the object side, and includes a focus group that is moved in the optical axis direction according to a change in the object distance in the imaging lens and focused.
  • the objective lens reduces the subject image and makes it incident on the spatial intermediate imaging plane, and the imaging lens enlarges the spatial intermediate imaging and re-images on the image sensor, and the formed optical system
  • An imaging apparatus comprising: an imaging element that converts an image into an electrical signal.
  • the number of spatial intermediate imaging is small, the loss of light amount reaching the imaging device can be suppressed, and a bright and clear image can be formed.
  • FIG. 6 is a longitudinal aberration diagram of the observation optical system according to the first example of the first invention in a state in which a long distance object is in focus.
  • A is a spherical aberration diagram
  • B is an astigmatism diagram
  • c is a distortion diagram.
  • FIG. 6 is a longitudinal aberration diagram of the observation optical system according to the first example of the first invention in a short-distance object focusing state.
  • FIG. 6 is a lateral aberration diagram in a state where a long-distance object is focused at the telephoto end of the observation optical system according to the first example of the first invention.
  • the horizontal axis indicates the distance from the principal ray on the pupil plane.
  • a solid line shows d line, a short broken line shows g line, and a long broken line shows C line.
  • (A) is a lateral aberration diagram without image stabilization at an image point of 70% of the maximum image height
  • (b) is a lateral aberration diagram without image stabilization at an axial image point
  • (c) is a lateral aberration diagram without image stabilization at an axial image point.
  • FIG. 4 is a lateral aberration diagram in which image stabilization is not performed at an image point at ⁇ 70% of the maximum image height.
  • D is a lateral aberration diagram in which image stabilization is performed at an image point of 70% of the maximum image height
  • (e) is a lateral aberration diagram in which image stabilization is performed at an on-axis image point
  • f is the maximum.
  • FIG. 6 is a lateral aberration diagram in which camera shake correction is performed at an image point at ⁇ 70% of the image height. It is an optical sectional view of an observation optical system of the 2nd example of the 1st invention, and shows a long-distance object focusing state.
  • FIG. 6 is a longitudinal aberration diagram of the observation optical system according to the second example of the first invention in the state of focusing on a long-distance object.
  • (A) is a spherical aberration diagram
  • (b) is an astigmatism diagram
  • (c) is a distortion diagram.
  • FIG. 6 is a longitudinal aberration diagram of the observation optical system according to the first example of the first invention in a short-distance object focusing state.
  • (A) is a spherical aberration diagram
  • (b) is an astigmatism diagram
  • (c) is a distortion diagram.
  • FIG. 6 is a lateral aberration diagram in a state where a long-distance object is in focus at the telephoto end of the observation optical system according to Example 2 of the first invention.
  • the horizontal axis indicates the distance from the principal ray on the pupil plane.
  • a solid line shows d line
  • a short broken line shows g line
  • a long broken line shows C line.
  • (A) is a lateral aberration diagram without image stabilization at an image point of 70% of the maximum image height
  • (b) is a lateral aberration diagram without image stabilization at an axial image point
  • FIG. 4 is a lateral aberration diagram in which image stabilization is not performed at an image point at ⁇ 70% of the maximum image height.
  • FIG. 6 is a lateral aberration diagram in which camera shake correction is performed at an image point at ⁇ 70% of the image height. It is an optical sectional view of an observation optical system of the 3rd example of the 1st invention, and shows a long-distance object focusing state. It is an optical sectional view of an observation optical system of the 3rd example of the 1st invention, and shows a short-distance object focusing state.
  • (A) is a spherical aberration diagram
  • (b) is an astigmatism diagram
  • (c) is a distortion diagram.
  • (A) is a spherical aberration diagram
  • (b) is an astigmatism diagram
  • (c) is a distortion diagram.
  • the horizontal axis indicates the distance from the principal ray on the pupil plane.
  • a solid line shows d line, a short broken line shows g line, and a long broken line shows C line.
  • (A) is a lateral aberration diagram without image stabilization at an image point of 70% of the maximum image height
  • (b) is a lateral aberration diagram without image stabilization at an axial image point
  • (c) is a lateral aberration diagram in which image stabilization is not performed at an image point at ⁇ 70% of the maximum image height.
  • FIG. 6 is a lateral aberration diagram in which camera shake correction is performed at an image point at ⁇ 70% of the image height. It is an optical sectional view of the observation optical system of the 4th example of the 1st invention, and shows a long-distance object focusing state. It is an optical sectional view of an observation optical system of the 4th example of the 1st invention, and shows a short-distance object focusing state.
  • (A) is a spherical aberration diagram
  • (b) is an astigmatism diagram
  • (c) is a distortion diagram
  • (A) is a spherical aberration diagram
  • (b) is an astigmatism diagram
  • (c) is a distortion diagram.
  • the horizontal axis indicates the distance from the principal ray on the pupil plane.
  • a solid line shows d line, a short broken line shows g line, and a long broken line shows C line.
  • (A) is a lateral aberration diagram without image stabilization at an image point of 70% of the maximum image height
  • (b) is a lateral aberration diagram without image stabilization at an axial image point
  • (c) is a lateral aberration diagram in which image stabilization is not performed at an image point at ⁇ 70% of the maximum image height.
  • FIG. 6 is a lateral aberration diagram in which camera shake correction is performed at an image point at ⁇ 70% of the image height. It is an optical sectional view of an observation optical system of the 5th example of the 1st invention, and shows a long-distance object focusing state. It is an optical sectional view of an observation optical system of the 5th example of the 1st invention, and shows a short-distance object focusing state.
  • FIG. 10 is a lateral aberration diagram in a state where a long-distance object is focused at the telephoto end of the observation optical system according to the fifth example of the first invention.
  • the horizontal axis indicates the distance from the principal ray on the pupil plane.
  • a solid line shows d line, a short broken line shows g line, and a long broken line shows C line.
  • (A) is a lateral aberration diagram without image stabilization at an image point of 70% of the maximum image height
  • (b) is a lateral aberration diagram without image stabilization at an axial image point
  • (c) is a lateral aberration diagram in which image stabilization is not performed at an image point at ⁇ 70% of the maximum image height.
  • FIG. 6 is a lateral aberration diagram in which camera shake correction is performed at an image point at ⁇ 70% of the image height. It is sectional explanatory drawing of the Example of the imaging device of 2nd invention.
  • the observation optical system according to the present invention includes an objective lens and an imaging lens in order from the object side, and the focusing group is moved by focusing in the optical axis direction in accordance with the variation of the object distance in the imaging lens.
  • the objective lens reduces the object image and makes it incident on the spatial intermediate imaging plane, and the imaging lens enlarges the spatial intermediate imaging and re-images it on the image sensor. .
  • the observation optical system according to the present invention preferably satisfies the following conditional expressions. (1) 0.050 ⁇ fo / fi ⁇ 1.100 fo: focal length of the objective lens fi: focal length of the imaging lens in the state of focusing on a long distance object
  • Conditional expression (1) relates to the ratio between the focal length of the objective lens and the focal length of the imaging lens in the state of focusing on a long-distance object.
  • this numerical value is below the lower limit, the focal length of the objective lens is shortened, resulting in a wide-angle lens. For this reason, unless the optical path length of the small-diameter portion on the object side is further increased, it is difficult to zoom in close to the subject. That is, it becomes difficult to reduce the size and resolution of the entire optical system. If this numerical value exceeds the upper limit, the focal length of the objective lens becomes long and a telephoto lens is obtained. For this reason, the angle of view to be captured is narrow, and it is difficult to grasp the surrounding conditions of the subject and the observation optical system.
  • Conditional expression (1) is preferably 0.100 ⁇ fo / fi ⁇ 0.850, more preferably 0.150 ⁇ fo / fi ⁇ 0.700, in order to achieve the above object.
  • the observation optical system according to the present invention preferably satisfies the following conditional expressions. (2) 0.000 ⁇ b1f ⁇ 0.100 (3) 3.000 ⁇ b2f ⁇ 6,500
  • b1f absolute value of paraxial lateral magnification when the objective lens is in focus with a long distance object
  • b2f absolute value of lateral magnification when the imaging lens is in focus with a long distance object
  • Conditional expression (2) relates to the absolute value of the paraxial lateral magnification when the objective lens is focused on a long-distance object. If this value falls below the lower limit, it is difficult to reduce the size of the entire optical system because the amount of movement of the focus group must be secured so that far-distance shooting can be performed. Also, if this value exceeds the upper limit, it is difficult to focus on a long-distance object, and as a result, unless the optical path length of the small-diameter portion on the object side is further increased, it is difficult to zoom in close to the object. Become. Furthermore, it is difficult to reduce the size and resolution of the entire optical system.
  • the observation optical system and the image pickup apparatus including the observation optical system have a wide field of view and can sufficiently recognize obstacles and the like around the observation optical system.
  • Conditional expression (2) is preferably 0.020 ⁇ b1f ⁇ 0.070, more preferably 0.030 ⁇ b1f ⁇ 0.050, in order to achieve the above object.
  • Conditional expression (3) relates to the absolute value of the paraxial lateral magnification when the imaging lens is focused on a long-distance object.
  • this numerical value is below the lower limit, spatial intermediate imaging is increased, the optical effective diameter of the small diameter portion is increased, and the image pickup device is reduced, so that it is difficult to achieve high resolution. If this value exceeds the upper limit, the spatial intermediate imaging becomes small, and it becomes difficult to achieve high resolution due to the diffraction limit. Furthermore, the image pickup device becomes large, and it is difficult to reduce the size of the image side lens group and the entire apparatus.
  • the observation optical system and the image pickup apparatus including the observation optical system are configured as described above, so that the entire lens length is long with respect to the image height, and the observation optical system that requires a sufficient length of the small diameter portion is also effective. Can be used for In addition, the observation optical system and the image pickup apparatus including the observation optical system have a small optical effective diameter on the object side, but can ensure a long optical path length in the small diameter portion and can cope with high resolution.
  • conditional expression (3) preferably satisfies 3.500 ⁇ b2f ⁇ 6.0000, and more preferably satisfies 4.000 ⁇ b2f ⁇ 5.500.
  • the observation optical system according to the present invention preferably satisfies the following conditional expressions. (4) 0.290 ⁇ (b1f ⁇ b2f) / (b1n ⁇ b2n) ⁇ 0.470
  • b1n Absolute value of the lateral magnification when the objective lens is focused on a short distance object
  • b2n Absolute value of the lateral magnification when the imaging lens is focused on a short distance object
  • Conditional expression (4) relates to the ratio of the imaging magnification between the long-distance object focused state and the short-range object focused state. If this value falls below the lower limit, it is difficult to reduce the size of the entire optical system because the amount of movement of the focus group must be secured so that far-distance shooting can be performed. If this numerical value exceeds the upper limit, the focus adjustment range becomes narrow, and it is difficult to increase the resolution at an object distance where the subject cannot be focused.
  • conditional expression (4) preferably satisfies 0.320 ⁇ (b1f ⁇ b2f) / (b1n ⁇ b2n) ⁇ 0.430, more preferably 0.350 ⁇ (b1f Xb2f) / (b1n * b2n) ⁇ 0.400.
  • the observation optical system according to the present invention preferably satisfies the following conditional expressions. (5) 0.800 ⁇ TanWf / TanWn ⁇ 1.400 However, Wf: Half field angle in the state of focusing on a long distance object Wn: Half field angle in the state of focusing on a short distance object
  • Conditional expression (5) relates to the ratio of the angle of view between the long-distance object focused state and the short-range object focused state.
  • Focus is used when incorporating an autofocus system that repeats the in-focus state and the out-of-focus state while calculating the contrast of the subject during movie shooting, or when changing the distance between the subject and the objective lens frequently. It is desirable that the change in the angle of view with respect to the movement of the group is small. When the change in the angle of view with respect to the movement of the focus group is large, a sense of incongruity occurs when shooting a moving image while performing autofocus.
  • Conditional expression (5) is preferably 0.850 ⁇ TanWf / TanWn ⁇ 1.200, more preferably 0.890 ⁇ TanWf / TanWn ⁇ 1.000 in order to achieve the above object.
  • the observation optical system according to the present invention further includes a camera shake correction lens group that performs a camera shake correction by moving the first lens group perpendicularly to the optical axis, and satisfies the following conditional expression: preferable.
  • (6) 0.700 ⁇ fv / f ⁇ 1.300
  • fv Focal length of the anti-vibration group
  • f Absolute value of the focal length of the entire system
  • Conditional expression (6) relates to the ratio between the focal length of the camera shake correction group and the focal length of the entire optical system in the far-field object focused state.
  • this value is below the lower limit, the power of the camera shake correction group becomes strong, and the correction of spherical aberration and coma aberration at the time of camera shake correction becomes insufficient. If this value exceeds the upper limit, the power of the camera shake correction group becomes weak, the amount of camera shake correction in the direction perpendicular to the optical axis of the camera shake correction group increases, and the outer diameter increases.
  • conditional expression (6) is preferably 0.800 ⁇ fv / f ⁇ 1.200, and more preferably 0.900 ⁇ fv / f ⁇ 1.100.
  • the objective lens has a symmetric lens portion in which the object side and the image side are also reversed in the imaging lens.
  • an observation optical system that includes a reasonable number of lenses and is sufficiently corrected for aberrations, and an imaging apparatus including the observation optical system.
  • the observation optical system has an objective lens and an imaging lens in order from the object side, and is moved in the imaging lens in the direction of the optical axis according to the variation of the object distance for focusing.
  • An observation optical system comprising a focus group, wherein the objective lens reduces a subject image and makes it incident on a spatial intermediate imaging plane, and the imaging lens enlarges the spatial intermediate imaging and re-images it on an image sensor.
  • a system and an image sensor that converts the formed optical image into an electrical signal are provided.
  • FNO FNO.
  • f the focal length (mm) of the entire system
  • W the half angle of view (°)
  • r the radius of curvature
  • d the lens thickness or lens spacing
  • Nd the refraction of the d line.
  • the rate and vd indicate the Abbe number based on the d-line.
  • G1 indicates a front lens group
  • G2 indicates a rear lens group.
  • IMG indicates imaging.
  • G3 represents a camera shake correction lens group
  • G4 represents a focusing lens group
  • G5 represents an imaging lens group.
  • the rear lens group G2 includes a camera shake correction lens group G3. 2, 3, 6, 7, 10, 11, 14, 15, 18, and 19, (a) shows spherical aberration (SA (mm)), and (b) shows astigmatism (AST). (Mm)), and (c) shows distortion (DIS (%)).
  • SA spherical aberration
  • AST astigmatism
  • DIS shows distortion
  • the vertical axis indicates the F number (indicated by FNO.
  • the solid line is the d line (d-line), the short broken line is the g line (g-line), and the long broken line is the C line (C -Line) aberration.
  • the vertical axis indicates the half field angle (indicated by W in the figure)
  • the solid line indicates the sagittal plane (indicated by S in the figure)
  • the broken line indicates the meridional plane (indicated by M in the figure).
  • Distortion aberration In the figure, the vertical axis represents a half angle of view (indicated by W in the figure).
  • 4, 8, 12, 16, and 20 are lateral aberration diagrams in the state of focusing on a long-distance object at the telephoto end of the observation optical system.
  • the horizontal axis indicates the distance from the principal ray on the pupil plane.
  • a solid line shows d line
  • a short broken line shows g line
  • a long broken line shows C line.
  • c is the curvature (1 / r)
  • h is the height from the optical axis
  • k is the conic coefficient
  • A4, A6, A8, A10... Are the aspheric coefficients of the respective orders.
  • FIG. 1 is an optical cross-sectional view
  • FIGS. 2 and 3 are longitudinal aberration diagrams in a long-distance object focusing state and a short-distance object focusing state, respectively.
  • Tables 1 and 2 show the numerical data.
  • the observation optical system of Example 1 includes an objective lens system OL (objective lens) and an imaging lens system IL (imaging lens) in order from the object side as shown in FIG.
  • the imaging lens system IL includes a rear lens group G2, a focusing lens group G4, and an imaging lens group G5.
  • the rear lens group G2 includes a camera shake correction lens group G3.
  • FIG. 5 is an optical cross-sectional view
  • FIGS. 6 and 7 are longitudinal aberration diagrams in a long-distance object focusing state and a short-distance object focusing state, respectively.
  • Tables 3 and 4 show the numerical data.
  • the observation optical system of Example 2 includes an objective lens system OL and an imaging lens system IL in order from the object side as shown in FIG. 5, and the objective lens system OL has a front lens group G1, and forms an image.
  • the lens system IL includes a rear lens group G2, a focusing lens group G4, and an imaging lens group G5.
  • the rear lens group G2 includes a camera shake correction lens group G3.
  • FIG. 9 is an optical cross-sectional view
  • FIGS. 10 and 11 are longitudinal aberration diagrams in a long-distance object focusing state and a short-distance object focusing state, respectively.
  • Tables 5 and 6 show the numerical data.
  • the observation optical system of Example 3 includes an objective lens system OL and an imaging lens system IL in order from the object side as shown in FIG. 9, and the objective lens system OL has a front lens group G1, and forms an image.
  • the lens system IL includes a rear lens group G2, a focusing lens group G4, and an imaging lens group G5.
  • the rear lens group G2 includes a camera shake correction lens group G3.
  • FIG. 13 is an optical cross-sectional view
  • FIGS. 14 and 15 are longitudinal aberration diagrams in a long-distance object focusing state and a short-distance object focusing state, respectively.
  • Tables 7 and 8 show the numerical data.
  • the observation optical system of Example 4 includes an objective lens system OL and an imaging lens system IL in order from the object side as shown in FIG. 13, and the objective lens system OL has a front lens group G1, and forms an image.
  • the lens system IL includes a rear lens group G2, a focusing lens group G4, and an imaging lens group G5.
  • the rear lens group G2 includes a camera shake correction lens group G3.
  • FIG. 17 is an optical cross-sectional view
  • FIGS. 18 and 19 are longitudinal aberration diagrams in a long-distance object focusing state and a short-distance object focusing state, respectively.
  • Tables 9 to 11 show the numerical data.
  • the observation optical system of Example 5 includes an objective lens system OL and an imaging lens system IL in order from the object side as shown in FIG. 17, and the objective lens system OL has a front lens group G1, and forms an image.
  • the lens system IL includes a rear lens group G2 and a focusing lens group G4. That is, the observation optical system of Example 5 does not have a lens group corresponding to the imaging lens group G5 included in the observation optical systems of Examples 1 to 4.
  • the rear lens group G2 includes a camera shake correction lens group G3.
  • the amount of movement of the image stabilizing group in the direction perpendicular to the optical axis in the camera shake correction state is all 0.330 mm. Further, the image stabilization angle at that time is as described below.
  • Example 1 0.604 degree
  • Example 2 0.605 degree
  • Example 3 0.581 degree
  • Example 4 0.623 degree
  • Example 5 0.723 degree
  • Table 12 shows values corresponding to the conditional expressions corresponding to the mathematical expressions described in the claims of the respective examples. (Table 12) Values corresponding to conditional expressions
  • illumination light emitted from the illumination light source 101 is irradiated to a subject (not shown) via the illumination light path 102.
  • the subject light reflected by the subject forms a spatial intermediate image IMG by the objective lens system OL.
  • the spatial intermediate imaging IMG is re-imaged on the imaging element 106 in the imaging device 105 by the imaging lens system IL.
  • the imaging signal output from the imaging element 106 is input to the display device 107, and the display device 107 displays the subject image.

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Abstract

Provided are: an optical system for observation in which the quantity of spatially intermediate image formation is small, loss in the amount of light arriving at an imaging element is minimized, and it is possible form a bright and clear image; and an imaging device provided with the optical system for observation. The optical system for observation is provided with a focusing group that comprises an objective lens and an image formation lens in order from the object side, and in which focusing is carried out by moving in the optical axis direction in accordance with variation in the object distance within the image formation lens. The objective lens shrinks a subject image and causes the result to enter a spatially intermediate image formation surface. The spatially intermediate image formation is enlarged by the image formation lens and image formation is carried out again on an imaging element.

Description

観察用光学系及びそれを備えた撮像装置Observation optical system and image pickup apparatus including the same
　本発明は、観察用光学系およびそれを備えた撮像装置に関する。 The present invention relates to an observation optical system and an image pickup apparatus including the observation optical system.
　近年、観察用光学系及びそれを備えた撮像装置は、限られた狭い空間に挿入して撮像するために、物体側レンズ群の小径化が望まれている。 In recent years, an observation optical system and an image pickup apparatus including the same have been desired to reduce the diameter of an object side lens group in order to insert an image in a limited narrow space.
　また、このような観察用光学系及びそれを備えた撮像装置においては、高解像度化も達成しなければならない課題の一つである。高解像度化は、被写体像をより細かく正確に確認するためのみならず、関係者間での情報の共有、または遠隔操作での被写体の確認等にも必要とされることからも、高解像度化が望まれている。 Also, in such an observation optical system and an image pickup apparatus including the same, it is one of the problems that must be achieved to achieve high resolution. Higher resolution is necessary not only for confirming the subject image in more detail and accuracy, but also for sharing information between the parties concerned or confirming the subject by remote control. Is desired.
　上述した従来の観察用光学系及びそれを備えた撮像装置における対物レンズの小径化は、高解像度化に関し、以下の三つの問題がある。
　第一は、Ｆナンバーが大きく暗い光学系にすると、前述したように小径化を実現することができる。しかし、Ｆナンバーが大きく暗い光学系を用いると、回折限界によって光学系の解像性能の限界が低くなり、高解像度の画質を達成できないという問題が生じる。 The reduction in the diameter of the objective lens in the above-described conventional observation optical system and an image pickup apparatus including the same has the following three problems with respect to higher resolution.
First, if the optical system has a large F number and is dark, the diameter can be reduced as described above. However, when an optical system having a large F number and a darkness is used, the resolution limit of the optical system is lowered due to the diffraction limit, resulting in a problem that high resolution image quality cannot be achieved.
　第二は、対物レンズによって形成される空間中間結像が小さいことである。例えば、対物レンズ及びリレーレンズ系を小径にし、かつそれに対応して空間中間結像も小径にすることで所定領域へ挿入される部分の全体を小径にすることが考えられる。一方で、高解像度化を実現するためには、対物レンズによる空間中間結像の解像度をリレーレンズ系の横倍率と、撮像素子に必要な解像度との積にすることが必要である。そのため、対物レンズに求められる解像度が高くなるため、レンズ枚数を多くしかつ有効径を大きくしなければならないという問題が生じる。 Second, the spatial intermediate image formed by the objective lens is small. For example, it is conceivable to reduce the diameter of the entire portion inserted into a predetermined region by reducing the diameter of the objective lens and the relay lens system and reducing the spatial intermediate imaging accordingly. On the other hand, in order to realize high resolution, it is necessary to set the resolution of the spatial intermediate imaging by the objective lens to the product of the lateral magnification of the relay lens system and the resolution required for the image sensor. For this reason, the resolution required for the objective lens is increased, which causes a problem that the number of lenses must be increased and the effective diameter must be increased.
　第三は、従来の観察用光学系では、物体側より順に、対物レンズ、単数又は複数のリレーレンズ系、接眼レンズ、結像レンズ、撮像素子の順で結像をリレーさせている。前記単数又は複数のリレーレンズ系は、小径部分の長さが一定以上長くして被写体に近接した撮像することを可能にするためである。しかし、複数の空間中間結像を形成した場合、各空間中間結像間で解像度が劣化することは避けられず、最終的には望んでいる高解像度の画質が得られないという問題が生じる。 Third, in the conventional observation optical system, the image formation is relayed in the order of the objective lens, the single or plural relay lens systems, the eyepiece lens, the imaging lens, and the imaging element in this order from the object side. This is because the single or plural relay lens systems make it possible to pick up an image close to the subject by making the length of the small diameter portion longer than a certain length. However, when a plurality of spatial intermediate images are formed, the resolution is inevitably deteriorated between the spatial intermediate images, and there is a problem that the desired high-resolution image quality cannot be finally obtained.
　従来の観察用対物レンズとして、挿入部先端側から順に、少なくとも、対物光学系、リレー光学系、接眼光学系からなる観察用光学系において、Ｎを前記リレー光学系のリレー回数として、前記リレー光学系を除く観察光学系が空気と接する負の屈折力の屈折面を（Ｎ＋４）面以上有することを特徴とする観察用対物レンズが提案されている（例えば、特許文献１参照）。 As a conventional observation objective lens, in the observation optical system including at least an objective optical system, a relay optical system, and an eyepiece optical system in order from the distal end side of the insertion portion, N is the relay frequency of the relay optical system, and the relay optical There has been proposed an observation objective lens in which an observation optical system other than the system has (N + 4) or more refractive surfaces having negative refractive power in contact with air (see, for example, Patent Document 1).
　従来の他の観察用対物レンズとして、負の屈折力を有する第１群と、正の屈折力を有する第２群と、負の屈折力を有する第３群と、正の屈折力を有する第４群とからなり、ワイド端における全系の焦点距離、第４群の焦点距離、ワイド端およびテレ端における第３群の倍率に係る所定条件式を満足すると共に、前記第３群を光軸に沿って移動させることにより倍率の変化と焦点合わせを同時に行なうようにした撮像装置用の対物レンズが提案されている（例えば、特許文献２参照）。 As another conventional objective lens for observation, a first group having negative refractive power, a second group having positive refractive power, a third group having negative refractive power, and a first group having positive refractive power And satisfying a predetermined conditional expression relating to the focal length of the entire system at the wide end, the focal length of the fourth group, the magnification of the third group at the wide end and the tele end, and the third group as the optical axis Has been proposed (see, for example, Patent Literature 2).
特開平１０－０７３７６２号公報Japanese Patent Laid-Open No. 10-073762 特許第２８７６２５２号公報Japanese Patent No. 2876252
　特許文献１によって提案された観察用対物レンズは、複数のリレーレンズを介しているために、空間中間結像の数が増えれば増える程、製造誤差等の影響で解像度が低下し、高解像度化が困難である。また長い光路内のガラスによる光量損失が大きいために、撮像素子に到達する光量が少なくなり、明るく鮮明な画像を形成できない問題がある。 Since the observation objective lens proposed by Patent Document 1 has a plurality of relay lenses, as the number of spatial intermediate imaging increases, the resolution decreases due to the influence of manufacturing errors and the like, resulting in higher resolution. Is difficult. In addition, since the loss of light amount due to the glass in the long optical path is large, there is a problem that the amount of light reaching the image sensor is reduced and a bright and clear image cannot be formed.
　特許文献２によって提案された観察用対物レンズは、対物レンズ内でレンズを可動にしていることから、その光学系のレンズの光学有効径の外側にレンズを可動とさせる作動装置を配置しなければならず、対物光学系の外径を小さくすることが困難である問題がある。 Since the observation objective lens proposed by Patent Document 2 moves the lens within the objective lens, an operating device that moves the lens outside the effective optical diameter of the lens of the optical system must be arranged. However, there is a problem that it is difficult to reduce the outer diameter of the objective optical system.
（発明の目的）
　本発明は、従来技術の対物レンズの上述した問題点に鑑みてなされたものであって、空間中間結像の数が少なく、撮像素子に到達する光量損失を抑え、明るく鮮明な画像を形成することができる観察用光学系及びそれを備えた撮像装置を提供することを目的とする。 (Object of invention)
The present invention has been made in view of the above-mentioned problems of the objective lens of the prior art, and the number of spatial intermediate imaging is small, the loss of light amount reaching the image sensor is suppressed, and a bright and clear image is formed. An object of the present invention is to provide an observation optical system and an imaging apparatus including the observation optical system.
　第１発明は、物体側から順に、対物レンズと、結像レンズとを持ち、前記結像レンズ中に物体距離の変動に応じて光軸方向に移動させてフォーカシングさせるフォーカス群を具備し、前記対物レンズは被写体像を縮小して空間中間結像面に入射させ、前記結像レンズでは前記空間中間結像を拡大して撮像素子上に再結像させることを特徴とする観察用光学系である。 The first invention includes an objective lens and an imaging lens in order from the object side, and includes a focus group that moves and focuses in the optical axis direction according to a change in the object distance in the imaging lens, An objective lens is an observation optical system characterized in that a subject image is reduced and incident on a spatial intermediate imaging plane, and the imaging lens enlarges the spatial intermediate imaging and re-images it on an image sensor. is there.
　第２発明は、物体側から順に、対物レンズと、結像レンズとを持ち、前記結像レンズ中に物体距離の変動に応じて光軸方向に移動させてフォーカシングさせるフォーカス群を具備し、前記対物レンズは被写体像を縮小して空間中間結像面に入射させ、前記結像レンズでは前記空間中間結像を拡大して撮像素子上に再結像させる観察用光学系と、形成された光学像を電気的信号に変換する撮像素子とを備えたことを特徴とする撮像装置である。 The second invention includes an objective lens and an imaging lens in order from the object side, and includes a focus group that is moved in the optical axis direction according to a change in the object distance in the imaging lens and focused. The objective lens reduces the subject image and makes it incident on the spatial intermediate imaging plane, and the imaging lens enlarges the spatial intermediate imaging and re-images on the image sensor, and the formed optical system An imaging apparatus comprising: an imaging element that converts an image into an electrical signal.
　本発明の観察用光学系及びそれを備えた撮像装置によれば、空間中間結像の数が少なく、撮像素子に到達する光量損失を抑え、明るく鮮明な画像を形成することができる。 According to the observation optical system of the present invention and the imaging apparatus including the observation optical system, the number of spatial intermediate imaging is small, the loss of light amount reaching the imaging device can be suppressed, and a bright and clear image can be formed.
第１発明の第１実施例の観察光学系の光学断面図であり、遠距離物体合焦状態を示す。It is an optical sectional view of an observation optical system of the 1st example of the 1st invention, and shows a long-distance object focusing state. 第１発明の第１実施例の観察光学系の光学断面図であり、近距離物体合焦状態を示す。It is an optical sectional view of the observation optical system of the 1st example of the 1st invention, and shows a short-distance object focusing state. 第１発明の第１実施例の観察光学系の遠距離物体合焦状態の縦収差図である。（ａ）は球面収差図であり、（ｂ）は非点収差図であり、（ｃ）は歪曲収差図である。FIG. 6 is a longitudinal aberration diagram of the observation optical system according to the first example of the first invention in a state in which a long distance object is in focus. (A) is a spherical aberration diagram, (b) is an astigmatism diagram, and (c) is a distortion diagram. 第１発明の第１実施例の観察光学系の近距離物体合焦状態の縦収差図である。（ａ）は球面収差図であり、（ｂ）は非点収差図であり、（ｃ）は歪曲収差図である。FIG. 6 is a longitudinal aberration diagram of the observation optical system according to the first example of the first invention in a short-distance object focusing state. (A) is a spherical aberration diagram, (b) is an astigmatism diagram, and (c) is a distortion diagram. 第１発明の第１実施例の観察光学系の望遠端で遠距離物体合焦状態の横収差図である。横軸は、瞳面上での主光線からの距離を示す。実線はｄ線を示し、短破線はｇ線を示し、長破線はＣ線を示す。（ａ）は最大像高の７０％の像点における手振れ補正を行っていない横収差図であり、（ｂ）は軸上像点における手振れ補正を行っていない横収差図であり、（ｃ）は最大像高の－７０％の像点における手振れ補正を行っていない横収差図である。（ｄ）は最大像高の７０％の像点における手振れ補正を行った横収差図であり、（ｅ）は軸上像点における手振れ補正を行った横収差図であり、（ｆ）は最大像高の－７０％の像点における手振れ補正を行った横収差図である。FIG. 6 is a lateral aberration diagram in a state where a long-distance object is focused at the telephoto end of the observation optical system according to the first example of the first invention. The horizontal axis indicates the distance from the principal ray on the pupil plane. A solid line shows d line, a short broken line shows g line, and a long broken line shows C line. (A) is a lateral aberration diagram without image stabilization at an image point of 70% of the maximum image height, (b) is a lateral aberration diagram without image stabilization at an axial image point, and (c). FIG. 4 is a lateral aberration diagram in which image stabilization is not performed at an image point at −70% of the maximum image height. (D) is a lateral aberration diagram in which image stabilization is performed at an image point of 70% of the maximum image height, (e) is a lateral aberration diagram in which image stabilization is performed at an on-axis image point, and (f) is the maximum. FIG. 6 is a lateral aberration diagram in which camera shake correction is performed at an image point at −70% of the image height. 第１発明の第２実施例の観察光学系の光学断面図であり、遠距離物体合焦状態を示す。It is an optical sectional view of an observation optical system of the 2nd example of the 1st invention, and shows a long-distance object focusing state. 第１発明の第２実施例の観察光学系の光学断面図であり、近距離物体合焦状態を示す。It is an optical sectional view of the observation optical system of the 2nd example of the 1st invention, and shows a short-distance object focusing state. 第１発明の第２実施例の観察光学系の遠距離物体合焦状態の縦収差図である。（ａ）は球面収差図であり、（ｂ）は非点収差図であり、（ｃ）は歪曲収差図である。FIG. 6 is a longitudinal aberration diagram of the observation optical system according to the second example of the first invention in the state of focusing on a long-distance object. (A) is a spherical aberration diagram, (b) is an astigmatism diagram, and (c) is a distortion diagram. 第１発明の第１実施例の観察光学系の近距離物体合焦状態の縦収差図である。（ａ）は球面収差図であり、（ｂ）は非点収差図であり、（ｃ）は歪曲収差図である。FIG. 6 is a longitudinal aberration diagram of the observation optical system according to the first example of the first invention in a short-distance object focusing state. (A) is a spherical aberration diagram, (b) is an astigmatism diagram, and (c) is a distortion diagram. 第１発明の第２実施例の観察光学系の望遠端で遠距離物体合焦状態の横収差図である。横軸は、瞳面上での主光線からの距離を示す。実線はｄ線を示し、短破線はｇ線を示し、長破線はＣ線を示す。（ａ）は最大像高の７０％の像点における手振れ補正を行っていない横収差図であり、（ｂ）は軸上像点における手振れ補正を行っていない横収差図であり、（ｃ）は最大像高の－７０％の像点における手振れ補正を行っていない横収差図である。（ｄ）は最大像高の７０％の像点における手振れ補正を行った横収差図であり、（ｅ）は軸上像点における手振れ補正を行った横収差図であり、（ｆ）は最大像高の－７０％の像点における手振れ補正を行った横収差図である。FIG. 6 is a lateral aberration diagram in a state where a long-distance object is in focus at the telephoto end of the observation optical system according to Example 2 of the first invention. The horizontal axis indicates the distance from the principal ray on the pupil plane. A solid line shows d line, a short broken line shows g line, and a long broken line shows C line. (A) is a lateral aberration diagram without image stabilization at an image point of 70% of the maximum image height, (b) is a lateral aberration diagram without image stabilization at an axial image point, and (c). FIG. 4 is a lateral aberration diagram in which image stabilization is not performed at an image point at −70% of the maximum image height. (D) is a lateral aberration diagram in which image stabilization is performed at an image point of 70% of the maximum image height, (e) is a lateral aberration diagram in which image stabilization is performed at an on-axis image point, and (f) is the maximum. FIG. 6 is a lateral aberration diagram in which camera shake correction is performed at an image point at −70% of the image height. 第１発明の第３実施例の観察光学系の光学断面図であり、遠距離物体合焦状態を示す。It is an optical sectional view of an observation optical system of the 3rd example of the 1st invention, and shows a long-distance object focusing state. 第１発明の第３実施例の観察光学系の光学断面図であり、近距離物体合焦状態を示す。It is an optical sectional view of an observation optical system of the 3rd example of the 1st invention, and shows a short-distance object focusing state. 第１発明の第３実施例の観察光学系の遠距離物体合焦状態の縦収差図である。（ａ）は球面収差図であり、（ｂ）は非点収差図であり、（ｃ）は歪曲収差図である。It is a longitudinal aberration figure of the long distance object focusing state of the observation optical system of 3rd Example of 1st invention. (A) is a spherical aberration diagram, (b) is an astigmatism diagram, and (c) is a distortion diagram. 第１発明の第３実施例の観察光学系の近距離物体合焦状態の縦収差図である。（ａ）は球面収差図であり、（ｂ）は非点収差図であり、（ｃ）は歪曲収差図である。It is a longitudinal aberration diagram of the short distance object focusing state of the observation optical system of the third example of the first invention. (A) is a spherical aberration diagram, (b) is an astigmatism diagram, and (c) is a distortion diagram. 第１発明の第４実施例の観察光学系の望遠端で遠距離物体合焦状態の横収差図である。横軸は、瞳面上での主光線からの距離を示す。実線はｄ線を示し、短破線はｇ線を示し、長破線はＣ線を示す。（ａ）は最大像高の７０％の像点における手振れ補正を行っていない横収差図であり、（ｂ）は軸上像点における手振れ補正を行っていない横収差図であり、（ｃ）は最大像高の－７０％の像点における手振れ補正を行っていない横収差図である。（ｄ）は最大像高の７０％の像点における手振れ補正を行った横収差図であり、（ｅ）は軸上像点における手振れ補正を行った横収差図であり、（ｆ）は最大像高の－７０％の像点における手振れ補正を行った横収差図である。It is a lateral aberration figure of a long-distance object focusing state in the telephoto end of the observation optical system of 4th Example of 1st invention. The horizontal axis indicates the distance from the principal ray on the pupil plane. A solid line shows d line, a short broken line shows g line, and a long broken line shows C line. (A) is a lateral aberration diagram without image stabilization at an image point of 70% of the maximum image height, (b) is a lateral aberration diagram without image stabilization at an axial image point, and (c). FIG. 4 is a lateral aberration diagram in which image stabilization is not performed at an image point at −70% of the maximum image height. (D) is a lateral aberration diagram in which image stabilization is performed at an image point of 70% of the maximum image height, (e) is a lateral aberration diagram in which image stabilization is performed at an on-axis image point, and (f) is the maximum. FIG. 6 is a lateral aberration diagram in which camera shake correction is performed at an image point at −70% of the image height. 第１発明の第４実施例の観察光学系の光学断面図であり、遠距離物体合焦状態を示す。It is an optical sectional view of the observation optical system of the 4th example of the 1st invention, and shows a long-distance object focusing state. 第１発明の第４実施例の観察光学系の光学断面図であり、近距離物体合焦状態を示す。It is an optical sectional view of an observation optical system of the 4th example of the 1st invention, and shows a short-distance object focusing state. 第１発明の第４実施例の観察光学系の遠距離物体合焦状態の縦収差図である。（ａ）は球面収差図であり、（ｂ）は非点収差図であり、（ｃ）は歪曲収差図である。It is a longitudinal aberration figure of the long distance object focusing state of the observation optical system of 4th Example of 1st invention. (A) is a spherical aberration diagram, (b) is an astigmatism diagram, and (c) is a distortion diagram. 第１発明の第４実施例の観察光学系の近距離物体合焦状態の縦収差図である。（ａ）は球面収差図であり、（ｂ）は非点収差図であり、（ｃ）は歪曲収差図である。It is a longitudinal aberration diagram of the short distance object focusing state of the observation optical system of the fourth example of the first invention. (A) is a spherical aberration diagram, (b) is an astigmatism diagram, and (c) is a distortion diagram. 第１発明の第４実施例の観察光学系の望遠端で遠距離物体合焦状態の横収差図である。横軸は、瞳面上での主光線からの距離を示す。実線はｄ線を示し、短破線はｇ線を示し、長破線はＣ線を示す。（ａ）は最大像高の７０％の像点における手振れ補正を行っていない横収差図であり、（ｂ）は軸上像点における手振れ補正を行っていない横収差図であり、（ｃ）は最大像高の－７０％の像点における手振れ補正を行っていない横収差図である。（ｄ）は最大像高の７０％の像点における手振れ補正を行った横収差図であり、（ｅ）は軸上像点における手振れ補正を行った横収差図であり、（ｆ）は最大像高の－７０％の像点における手振れ補正を行った横収差図である。It is a lateral aberration figure of a long-distance object focusing state in the telephoto end of the observation optical system of 4th Example of 1st invention. The horizontal axis indicates the distance from the principal ray on the pupil plane. A solid line shows d line, a short broken line shows g line, and a long broken line shows C line. (A) is a lateral aberration diagram without image stabilization at an image point of 70% of the maximum image height, (b) is a lateral aberration diagram without image stabilization at an axial image point, and (c). FIG. 4 is a lateral aberration diagram in which image stabilization is not performed at an image point at −70% of the maximum image height. (D) is a lateral aberration diagram in which image stabilization is performed at an image point of 70% of the maximum image height, (e) is a lateral aberration diagram in which image stabilization is performed at an on-axis image point, and (f) is the maximum. FIG. 6 is a lateral aberration diagram in which camera shake correction is performed at an image point at −70% of the image height. 第１発明の第５実施例の観察光学系の光学断面図であり、遠距離物体合焦状態を示す。It is an optical sectional view of an observation optical system of the 5th example of the 1st invention, and shows a long-distance object focusing state. 第１発明の第５実施例の観察光学系の光学断面図であり、近距離物体合焦状態を示す。It is an optical sectional view of an observation optical system of the 5th example of the 1st invention, and shows a short-distance object focusing state. 第１発明の第５実施例の観察光学系の遠距離物体合焦状態の縦収差図である。（ａ）は球面収差図であり、（ｂ）は非点収差図であり、（ｃ）は歪曲収差図である。It is a longitudinal aberration figure of the long distance object focusing state of the observation optical system of the 5th example of the 1st invention. (A) is a spherical aberration diagram, (b) is an astigmatism diagram, and (c) is a distortion diagram. 第１発明の第５実施例の観察光学系の近距離物体合焦状態の縦収差図である。（ａ）は球面収差図であり、（ｂ）は非点収差図であり、（ｃ）は歪曲収差図である。It is a longitudinal aberration diagram of the short distance object focusing state of the observation optical system of the fifth example of the first invention. (A) is a spherical aberration diagram, (b) is an astigmatism diagram, and (c) is a distortion diagram. 第１発明の第５実施例の観察光学系の望遠端で遠距離物体合焦状態の横収差図である。横軸は、瞳面上での主光線からの距離を示す。実線はｄ線を示し、短破線はｇ線を示し、長破線はＣ線を示す。（ａ）は最大像高の７０％の像点における手振れ補正を行っていない横収差図であり、（ｂ）は軸上像点における手振れ補正を行っていない横収差図であり、（ｃ）は最大像高の－７０％の像点における手振れ補正を行っていない横収差図である。（ｄ）は最大像高の７０％の像点における手振れ補正を行った横収差図であり、（ｅ）は軸上像点における手振れ補正を行った横収差図であり、（ｆ）は最大像高の－７０％の像点における手振れ補正を行った横収差図である。FIG. 10 is a lateral aberration diagram in a state where a long-distance object is focused at the telephoto end of the observation optical system according to the fifth example of the first invention. The horizontal axis indicates the distance from the principal ray on the pupil plane. A solid line shows d line, a short broken line shows g line, and a long broken line shows C line. (A) is a lateral aberration diagram without image stabilization at an image point of 70% of the maximum image height, (b) is a lateral aberration diagram without image stabilization at an axial image point, and (c). FIG. 4 is a lateral aberration diagram in which image stabilization is not performed at an image point at −70% of the maximum image height. (D) is a lateral aberration diagram in which image stabilization is performed at an image point of 70% of the maximum image height, (e) is a lateral aberration diagram in which image stabilization is performed at an on-axis image point, and (f) is the maximum. FIG. 6 is a lateral aberration diagram in which camera shake correction is performed at an image point at −70% of the image height. 第２発明の撮像装置の実施例の断面説明図である。It is sectional explanatory drawing of the Example of the imaging device of 2nd invention.
　以下、本発明の観察用光学系及びそれを備えた撮像装置について説明する。
　本発明に係る観察用光学系は、物体側から順に、対物レンズと、結像レンズとを持ち、前記結像レンズ中に物体距離の変動に応じて光軸方向に移動させてフォーカシングさせるフォーカス群を具備し、前記対物レンズは被写体像を縮小して空間中間結像面に入射させ、前記結像レンズでは前記空間中間結像を拡大して撮像素子上に再結像させることを特徴とする。 Hereinafter, the observation optical system of the present invention and an image pickup apparatus including the same will be described.
The observation optical system according to the present invention includes an objective lens and an imaging lens in order from the object side, and the focusing group is moved by focusing in the optical axis direction in accordance with the variation of the object distance in the imaging lens. The objective lens reduces the object image and makes it incident on the spatial intermediate imaging plane, and the imaging lens enlarges the spatial intermediate imaging and re-images it on the image sensor. .
　このような観察用光学系及びそれを備えた撮像装置によれば、空間中間結像の数が少なく、撮像素子に到達する光量損失を抑え、明るく鮮明な画像を形成することができる。 According to such an observation optical system and an image pickup apparatus including the same, it is possible to form a bright and clear image by reducing the number of spatial intermediate images, suppressing loss of light amount reaching the image pickup device.
　本発明に係る観察用光学系はまた、以下の条件式を満足することが好ましい。
（１） ０．０５０≦ｆｏ／ｆｉ≦１．１００
ｆｏ：対物レンズの焦点距離
ｆｉ：結像レンズの遠距離物体合焦状態での焦点距離 The observation optical system according to the present invention preferably satisfies the following conditional expressions.
(1) 0.050 ≦ fo / fi ≦ 1.100
fo: focal length of the objective lens fi: focal length of the imaging lens in the state of focusing on a long distance object
　条件式（１）は、対物レンズの焦点距離と結像レンズの遠距離物体合焦状態での焦点距離の比に関する。この数値が下限を下回ると、対物レンズの焦点距離が短くなり、広角レンズとなる。そのため、物体側の小径部分の光路長を更に長くしないと被写体に近接させて拡大観察することが困難となる。すなわち、光学系全体の小型化や高解像度化が困難となる。また、この数値が上限を超えると、対物レンズの焦点距離が長くなり、望遠レンズとなる。そのため、取り込む画角が狭く、被写体や観察用光学系の周辺状況を把握することが困難となる。 Conditional expression (1) relates to the ratio between the focal length of the objective lens and the focal length of the imaging lens in the state of focusing on a long-distance object. When this numerical value is below the lower limit, the focal length of the objective lens is shortened, resulting in a wide-angle lens. For this reason, unless the optical path length of the small-diameter portion on the object side is further increased, it is difficult to zoom in close to the subject. That is, it becomes difficult to reduce the size and resolution of the entire optical system. If this numerical value exceeds the upper limit, the focal length of the objective lens becomes long and a telephoto lens is obtained. For this reason, the angle of view to be captured is narrow, and it is difficult to grasp the surrounding conditions of the subject and the observation optical system.
　条件式（１）は、前記目的を達成するために、好ましくは、　０．１００≦ｆｏ／ｆｉ　≦０．８５０であり、より好ましくは、０．１５０≦ｆｏ／ｆｉ≦０．７００である。 Conditional expression (1) is preferably 0.100 ≦ fo / fi ≦ 0.850, more preferably 0.150 ≦ fo / fi ≦ 0.700, in order to achieve the above object.
　本発明に係る観察用光学系はまた、以下の条件式を満足することが好ましい。
（２） ０．０００≦ｂ１ｆ≦０．１００
（３） ３．０００≦ｂ２ｆ≦６．５００
ただし、
ｂ１ｆ：対物レンズの遠距離物体合焦状態での近軸横倍率の絶対値
ｂ２ｆ：結像レンズの遠距離物体合焦状態での横倍率の絶対値 The observation optical system according to the present invention preferably satisfies the following conditional expressions.
(2) 0.000 ≦ b1f ≦ 0.100
(3) 3.000 ≦ b2f ≦ 6,500
However,
b1f: absolute value of paraxial lateral magnification when the objective lens is in focus with a long distance object b2f: absolute value of lateral magnification when the imaging lens is in focus with a long distance object
　条件式（２）は、対物レンズの遠距離物体合焦状態での近軸横倍率の絶対値に関する。この数値が下限を下回ると、より遠方の撮影ができるようにフォーカス群の移動量を確保しなければいけないために、光学系全体の小型化が困難となる。また、この数値が上限を超えると、遠距離物体への合焦が困難となり、その結果物体側の小径部分の光路長を更に長く取らないと対象物に近接させて拡大観察することが困難となる。さらに、光学系全体の小型化や高解像度化が困難となる。 Conditional expression (2) relates to the absolute value of the paraxial lateral magnification when the objective lens is focused on a long-distance object. If this value falls below the lower limit, it is difficult to reduce the size of the entire optical system because the amount of movement of the focus group must be secured so that far-distance shooting can be performed. Also, if this value exceeds the upper limit, it is difficult to focus on a long-distance object, and as a result, unless the optical path length of the small-diameter portion on the object side is further increased, it is difficult to zoom in close to the object. Become. Furthermore, it is difficult to reduce the size and resolution of the entire optical system.
　観察用光学系及びそれを備えた撮像装置は、上述の構成により、広い視野を有し、観察用光学系の周辺にある障害物等を十分に視認することができる。 The observation optical system and the image pickup apparatus including the observation optical system have a wide field of view and can sufficiently recognize obstacles and the like around the observation optical system.
　条件式（２）は、前記目的を達成するために、好ましくは、０．０２０≦ｂ１ｆ≦０．０７０であり、より好ましくは、０．０３０≦ｂ１ｆ≦０．０５０である。 Conditional expression (2) is preferably 0.020 ≦ b1f ≦ 0.070, more preferably 0.030 ≦ b1f ≦ 0.050, in order to achieve the above object.
　条件式（３）は、結像レンズの遠距離物体合焦状態での近軸横倍率の絶対値に関する。この数値が下限を下回ると、空間中間結像が大きくなって小径部分の光学有効径が大きくなり、かつ撮像素子が小さくなるため、高解像度化が困難となる。また、この数値が上限を超えると、空間中間結像が小さくなって回折限界により高解像度化が困難になる。さらに、撮像素子が大きくなり、像側レンズ群及び装置全体の小型化が困難となる。 Conditional expression (3) relates to the absolute value of the paraxial lateral magnification when the imaging lens is focused on a long-distance object. When this numerical value is below the lower limit, spatial intermediate imaging is increased, the optical effective diameter of the small diameter portion is increased, and the image pickup device is reduced, so that it is difficult to achieve high resolution. If this value exceeds the upper limit, the spatial intermediate imaging becomes small, and it becomes difficult to achieve high resolution due to the diffraction limit. Furthermore, the image pickup device becomes large, and it is difficult to reduce the size of the image side lens group and the entire apparatus.
　観察用光学系及びそれを備えた撮像装置は、上述のように構成することにより、像高に対してレンズ全長が長く、小径部分の十分な長さを必要とする観察用光学系にも有効に使用することができる。また、観察用光学系及びそれを備えた撮像装置は、物体側の光学有効径が小径でありながら、小径部分の光路長を長く確保でき、高解像度化に対応することもできる。 The observation optical system and the image pickup apparatus including the observation optical system are configured as described above, so that the entire lens length is long with respect to the image height, and the observation optical system that requires a sufficient length of the small diameter portion is also effective. Can be used for In addition, the observation optical system and the image pickup apparatus including the observation optical system have a small optical effective diameter on the object side, but can ensure a long optical path length in the small diameter portion and can cope with high resolution.
　条件式（３）は、前記目的を達成するために、好ましくは、３．５００≦ｂ２ｆ≦６．０００であり、より好ましくは、４．０００≦ｂ２ｆ≦５．５００である。 In order to achieve the above object, conditional expression (3) preferably satisfies 3.500 ≦ b2f ≦ 6.0000, and more preferably satisfies 4.000 ≦ b2f ≦ 5.500.
　本発明に係る観察用光学系はまた、以下の条件式を満足することが好ましい。
（４） ０．２９０≦(ｂ１ｆ×ｂ２ｆ)／(ｂ１ｎ×ｂ２ｎ)≦０．４７０
　ただし、
ｂ１ｎ：対物レンズの近距離物体合焦状態での横倍率の絶対値
ｂ２ｎ：結像レンズの近距離物体合焦状態での横倍率の絶対値 The observation optical system according to the present invention preferably satisfies the following conditional expressions.
(4) 0.290 ≦ (b1f × b2f) / (b1n × b2n) ≦ 0.470
However,
b1n: Absolute value of the lateral magnification when the objective lens is focused on a short distance object b2n: Absolute value of the lateral magnification when the imaging lens is focused on a short distance object
　条件式（４）は、遠距離物体合焦状態と近距離物体合焦状態との結像倍率の比に関する。この数値が下限を下回ると、より遠方の撮影ができるようにフォーカス群の移動量を確保しなければいけないために、光学系全体の小型化が困難となる。また、この数値が上限を超えると、フォーカス調整範囲が狭くなり、被写体に合焦できない物体距離においては高解像度化が困難となる。 Conditional expression (4) relates to the ratio of the imaging magnification between the long-distance object focused state and the short-range object focused state. If this value falls below the lower limit, it is difficult to reduce the size of the entire optical system because the amount of movement of the focus group must be secured so that far-distance shooting can be performed. If this numerical value exceeds the upper limit, the focus adjustment range becomes narrow, and it is difficult to increase the resolution at an object distance where the subject cannot be focused.
　条件式（４）は、前記目的を達成するために、好ましくは、０．３２０≦（ｂ１ｆ×ｂ２ｆ）／（ｂ１ｎ×ｂ２ｎ）≦０．４３０であり、より好ましくは、０．３５０≦（ｂ１ｆ×ｂ２ｆ）／（ｂ１ｎ×ｂ２ｎ）≦０．４００である。 In order to achieve the above object, conditional expression (4) preferably satisfies 0.320 ≦ (b1f × b2f) / (b1n × b2n) ≦ 0.430, more preferably 0.350 ≦ (b1f Xb2f) / (b1n * b2n) ≦ 0.400.
　本発明に係る観察用光学系はまた、以下の条件式を満足することが好ましい。
（５） ０．８００≦ＴａｎＷｆ／ＴａｎＷｎ≦１．４００
　ただし、
Ｗｆ：遠距離物体合焦状態での半画角
Ｗｎ：近距離物体合焦状態での半画角 The observation optical system according to the present invention preferably satisfies the following conditional expressions.
(5) 0.800 ≦ TanWf / TanWn ≦ 1.400
However,
Wf: Half field angle in the state of focusing on a long distance object Wn: Half field angle in the state of focusing on a short distance object
　条件式（５）は、遠距離物体合焦状態と近距離物体合焦状態との画角の比に関する。動画撮影時に被写体のコントラストを演算しながら合焦状態、非合焦状態を繰り返すようなオートフォーカスシステムを組み込んだ場合や、被写体と対物レンズの間隔を頻繁に変化させて撮像する際などに、フォーカス群の移動に対する画角の変化が小さいことが望まれる。フォーカス群の移動に対する画角の変化が大きい場合には、オートフォーカスをさせながら動画撮影する際に違和感が生じる。また、物体距離に対する対象物の拡大倍率のリニアリティーが損なわれると、被写体と対物レンズの距離間隔が不明確となり、対物レンズと対象物とが接触してしまう等の問題が生じやすい。本条件式はその問題が生じにくい望ましい領域を定めたものである。 Conditional expression (5) relates to the ratio of the angle of view between the long-distance object focused state and the short-range object focused state. Focus is used when incorporating an autofocus system that repeats the in-focus state and the out-of-focus state while calculating the contrast of the subject during movie shooting, or when changing the distance between the subject and the objective lens frequently. It is desirable that the change in the angle of view with respect to the movement of the group is small. When the change in the angle of view with respect to the movement of the focus group is large, a sense of incongruity occurs when shooting a moving image while performing autofocus. In addition, when the linearity of the magnification of the object with respect to the object distance is impaired, the distance between the subject and the objective lens becomes unclear, and problems such as contact between the objective lens and the object are likely to occur. This conditional expression defines a desirable region where the problem is unlikely to occur.
　条件式（５）は、前記目的を達成するために、好ましくは、０．８５０≦ＴａｎＷｆ／ＴａｎＷｎ≦１．２００であり、より好ましくは、０．８９０≦ＴａｎＷｆ／ＴａｎＷｎ≦１．０００である。 Conditional expression (5) is preferably 0.850 ≦ TanWf / TanWn ≦ 1.200, more preferably 0.890 ≦ TanWf / TanWn ≦ 1.000 in order to achieve the above object.
　本発明に係る観察用光学系はまた、前記第一レンズ群内に、光軸に対して垂直に移動させて手振れ補正を行う手振れ補正レンズ群を具備し、以下の条件式を満足することが好ましい。
（６） ０．７００≦ｆｖ／ｆ≦１．３００
　ただし、
ｆｖ：防振群の焦点距離
ｆ：全系の焦点距離の絶対値 The observation optical system according to the present invention further includes a camera shake correction lens group that performs a camera shake correction by moving the first lens group perpendicularly to the optical axis, and satisfies the following conditional expression: preferable.
(6) 0.700 ≦ fv / f ≦ 1.300
However,
fv: Focal length of the anti-vibration group f: Absolute value of the focal length of the entire system
　条件式（６）は、手振れ補正群の焦点距離と遠距離物体合焦状態における光学系全系の焦点距離の比に関する。この数値が下限を下回ると、手振れ補正群のパワーが強くなり、手振れ補正時の球面収差やコマ収差の収差補正が不十分となる。また、この数値が上限を超えると、手振れ補正群のパワーが弱くなり、手振れ補正群の光軸に対する垂直方向の手振れ補正量が大きくなり、外径が大きくなる。 Conditional expression (6) relates to the ratio between the focal length of the camera shake correction group and the focal length of the entire optical system in the far-field object focused state. When this value is below the lower limit, the power of the camera shake correction group becomes strong, and the correction of spherical aberration and coma aberration at the time of camera shake correction becomes insufficient. If this value exceeds the upper limit, the power of the camera shake correction group becomes weak, the amount of camera shake correction in the direction perpendicular to the optical axis of the camera shake correction group increases, and the outer diameter increases.
　上述の構成によれば、フォーカス機能を有し、さらに防振群を容易に組み込むことができるため、使い勝手の良い観察用光学系及びそれを備えた撮像装置を構成することができる。 According to the above-described configuration, since it has a focus function and a vibration-proof group can be easily incorporated, it is possible to configure an easy-to-use observation optical system and an imaging apparatus including the same.
　条件式（６）は、前記目的を達成するために、好ましくは、０．８００≦ｆｖ／ｆ≦１．２００であり、より好ましくは、０．９００≦ｆｖ／ｆ≦１．１００である。 In order to achieve the above object, conditional expression (6) is preferably 0.800 ≦ fv / f ≦ 1.200, and more preferably 0.900 ≦ fv / f ≦ 1.100.
　本発明に係る観察用光学系はまた、前記対物レンズが、前記結像レンズ内にも物体側と像側が逆転して存在し、対称型レンズ部を有することが好ましい。 In the observation optical system according to the present invention, it is also preferable that the objective lens has a symmetric lens portion in which the object side and the image side are also reversed in the imaging lens.
　観察用光学系をこのように構成して対称型レンズ部を設けることにより、諸収差を容易に良好に補正することができる。また、同一のレンズ部材を２組使用することにより製造コストを下げることができる。 By constructing the observation optical system in this way and providing a symmetrical lens portion, various aberrations can be easily and satisfactorily corrected. Further, the manufacturing cost can be reduced by using two sets of the same lens member.
　また、上述の構成によれば、さらに、合理的な枚数のレンズを含み、十分に収差補正された観察用光学系及びそれを備えた撮像装置を構成することもできる。 Further, according to the above-described configuration, it is also possible to configure an observation optical system that includes a reasonable number of lenses and is sufficiently corrected for aberrations, and an imaging apparatus including the observation optical system.
　また、本発明に係る観察用光学系は、物体側から順に、対物レンズと、結像レンズとを持ち、前記結像レンズ中に物体距離の変動に応じて光軸方向に移動させてフォーカシングさせるフォーカス群を具備し、前記対物レンズは被写体像を縮小して空間中間結像面に入射させ、前記結像レンズでは前記空間中間結像を拡大して撮像素子上に再結像させる観察用光学系と、形成された光学像を電気的信号に変換する撮像素子とを備えたことを特徴とする。 The observation optical system according to the present invention has an objective lens and an imaging lens in order from the object side, and is moved in the imaging lens in the direction of the optical axis according to the variation of the object distance for focusing. An observation optical system comprising a focus group, wherein the objective lens reduces a subject image and makes it incident on a spatial intermediate imaging plane, and the imaging lens enlarges the spatial intermediate imaging and re-images it on an image sensor. A system and an image sensor that converts the formed optical image into an electrical signal are provided.
　以下、本発明の数値実施例を示す。
　以下の表において、FNO.はFナンバー、ｆは全系の焦点距離（ｍｍ）、Wは半画角（°）、rは曲率半径、dはレンズ厚またはレンズ間隔、Ndはd線の屈折率、vdはd線基準のアッベ数を示す。 Hereinafter, numerical examples of the present invention will be shown.
In the table below, FNO. Is the F number, f is the focal length (mm) of the entire system, W is the half angle of view (°), r is the radius of curvature, d is the lens thickness or lens spacing, and Nd is the refraction of the d line. The rate and vd indicate the Abbe number based on the d-line.
　図１，５，９，１３，１７の各光学断面図において、数字１，２，３，・・・・は面番号を示し、Ｇ１が前レンズ群を示し、Ｇ２は後レンズ群を示す。ＩＭＧは、結像を示す。Ｇ３は手振れ補正レンズ群を示し、Ｇ４は合焦レンズ群を示し、Ｇ５は撮像レンズ群を示す。後レンズ群Ｇ２は手振れ補正レンズ群Ｇ３を含む。
　図２，３，６，７，１０，１１，１４，１５，１８、１９の各収差図において、（ａ）は球面収差（ＳＡ（ｍｍ））を示し、（ｂ）は非点収差（ＡＳＴ（ｍｍ））を示し、（ｃ）は歪曲収差（ＤＩＳ（％））を示す。
　球面収差図において、縦軸はＦナンバー（図中、FNO.で示す）を示し、実線はｄ線（ｄ－ｌｉｎｅ）、短破線はｇ線（ｇ－ｌｉｎｅ）、長破線はＣ線（Ｃ－ｌｉｎｅ）の収差を示す。非点収差図において、縦軸は半画角（図中、Ｗで示す）を示し、実線はサジタル平面（図中、Ｓで示す）、破線はメリディオナル平面（図中、Ｍで示す）を示す。歪曲収差　図において、縦軸は半画角（図中、Ｗで示す）を示す。
　図４，８，１２，１６，２０は、観察光学系の望遠端で遠距離物体合焦状態の横収差図である。横軸は、瞳面上での主光線からの距離を示す。実線はｄ線を示し、短破線はｇ線を示し、長破線はＣ線を示す。 In the optical sectional views of FIGS. 1, 5, 9, 13, and 17, numerals 1, 2, 3,... Indicate surface numbers, G1 indicates a front lens group, and G2 indicates a rear lens group. IMG indicates imaging. G3 represents a camera shake correction lens group, G4 represents a focusing lens group, and G5 represents an imaging lens group. The rear lens group G2 includes a camera shake correction lens group G3.
2, 3, 6, 7, 10, 11, 14, 15, 18, and 19, (a) shows spherical aberration (SA (mm)), and (b) shows astigmatism (AST). (Mm)), and (c) shows distortion (DIS (%)).
In the spherical aberration diagram, the vertical axis indicates the F number (indicated by FNO. In the figure), the solid line is the d line (d-line), the short broken line is the g line (g-line), and the long broken line is the C line (C -Line) aberration. In the astigmatism diagram, the vertical axis indicates the half field angle (indicated by W in the figure), the solid line indicates the sagittal plane (indicated by S in the figure), and the broken line indicates the meridional plane (indicated by M in the figure). . Distortion aberration In the figure, the vertical axis represents a half angle of view (indicated by W in the figure).
4, 8, 12, 16, and 20 are lateral aberration diagrams in the state of focusing on a long-distance object at the telephoto end of the observation optical system. The horizontal axis indicates the distance from the principal ray on the pupil plane. A solid line shows d line, a short broken line shows g line, and a long broken line shows C line.
　非球面は次式で定義される。
z=ch2/[1+{1-(1+k)c2h2}1/2]+A4h4+A6h6+A8h8+A10h10・・・
　但し、cは曲率(1/r)、hは光軸からの高さ、kは円錐係数、A4、A6、A8、A10・・・は各次数の非球面係数を示す。 An aspheric surface is defined by the following equation.
z = ch 2 / [1+ {1- (1 + k) c 2 h 2 } 1/2 ] + A4h 4 + A6h 6 + A8h 8 + A10h 10 ...
Where c is the curvature (1 / r), h is the height from the optical axis, k is the conic coefficient, A4, A6, A8, A10... Are the aspheric coefficients of the respective orders.
　本発明による観察用光学系の実施例１を図面を参照して説明する。図１は光学断面図、図２,３はそれぞれ遠距離物体合焦状態、近距離物体合焦状態での縦収差図である。表１,２はその数値データである。 Embodiment 1 of the observation optical system according to the present invention will be described with reference to the drawings. FIG. 1 is an optical cross-sectional view, and FIGS. 2 and 3 are longitudinal aberration diagrams in a long-distance object focusing state and a short-distance object focusing state, respectively. Tables 1 and 2 show the numerical data.
　実施例１の観察用光学系は、図１に示すように物体側から順に、対物レンズ系ＯＬ（対物レンズ）と結像レンズ系ＩＬ（結像レンズ）とを備え、対物レンズ系ＯＬは前レンズ群Ｇ１を有し、結像レンズ系ＩＬは後レンズ群Ｇ２、合焦レンズ群Ｇ４、及び撮像レンズ群Ｇ５を有する。後レンズ群Ｇ２は、手振れ補正レンズ群Ｇ３を含む。 The observation optical system of Example 1 includes an objective lens system OL (objective lens) and an imaging lens system IL (imaging lens) in order from the object side as shown in FIG. The imaging lens system IL includes a rear lens group G2, a focusing lens group G4, and an imaging lens group G5. The rear lens group G2 includes a camera shake correction lens group G3.
　（表１）諸元表
FNO.＝14.629
f　 ＝27.771
Ｙ  ＝17.000
Figure JPOXMLDOC01-appb-I000001

Figure JPOXMLDOC01-appb-I000002
（表２）可変間隔表
Figure JPOXMLDOC01-appb-I000003
(Table 1) Specifications
FNO. = 14.629
f = 27.771
Y = 17.000
Figure JPOXMLDOC01-appb-I000001

Figure JPOXMLDOC01-appb-I000002
(Table 2) Variable interval table
Figure JPOXMLDOC01-appb-I000003
　本発明による観察用光学系の実施例２を図面を参照して説明する。図５は光学断面図、図６,７はそれぞれ遠距離物体合焦状態、近距離物体合焦状態での縦収差図である。表３,４はその数値データである。 Example 2 of the observation optical system according to the present invention will be described with reference to the drawings. FIG. 5 is an optical cross-sectional view, and FIGS. 6 and 7 are longitudinal aberration diagrams in a long-distance object focusing state and a short-distance object focusing state, respectively. Tables 3 and 4 show the numerical data.
　実施例２の観察用光学系は、図５に示すように物体側から順に、対物レンズ系ＯＬと結像レンズ系ＩＬとを備え、対物レンズ系ＯＬは前レンズ群Ｇ１を有し、結像レンズ系ＩＬは後レンズ群Ｇ２、合焦レンズ群Ｇ４、及び撮像レンズ群Ｇ５を有する。後レンズ群Ｇ２は、手振れ補正レンズ群Ｇ３を含む。 The observation optical system of Example 2 includes an objective lens system OL and an imaging lens system IL in order from the object side as shown in FIG. 5, and the objective lens system OL has a front lens group G1, and forms an image. The lens system IL includes a rear lens group G2, a focusing lens group G4, and an imaging lens group G5. The rear lens group G2 includes a camera shake correction lens group G3.
　（表３）諸元表
FNO.＝14.567
f   ＝27.805
Ｙ  ＝17.000
Figure JPOXMLDOC01-appb-I000004

Figure JPOXMLDOC01-appb-I000005
（表４）可変間隔表
Figure JPOXMLDOC01-appb-I000006
(Table 3) Specifications
FNO. = 14.567
f = 27.805
Y = 17.000
Figure JPOXMLDOC01-appb-I000004

Figure JPOXMLDOC01-appb-I000005
(Table 4) Variable interval table
Figure JPOXMLDOC01-appb-I000006
　本発明による観察用光学系の実施例３を図面を参照して説明する。図９は光学断面図、図１０,１１はそれぞれ遠距離物体合焦状態、近距離物体合焦状態での縦収差図である。
表５,６はその数値データである。 Example 3 of the observation optical system according to the present invention will be described with reference to the drawings. FIG. 9 is an optical cross-sectional view, and FIGS. 10 and 11 are longitudinal aberration diagrams in a long-distance object focusing state and a short-distance object focusing state, respectively.
Tables 5 and 6 show the numerical data.
　実施例３の観察用光学系は、図９に示すように物体側から順に、対物レンズ系ＯＬと結像レンズ系ＩＬとを備え、対物レンズ系ＯＬは前レンズ群Ｇ１を有し、結像レンズ系ＩＬは後レンズ群Ｇ２、合焦レンズ群Ｇ４、及び撮像レンズ群Ｇ５を有する。後レンズ群Ｇ２は、手振れ補正レンズ群Ｇ３を含む。 The observation optical system of Example 3 includes an objective lens system OL and an imaging lens system IL in order from the object side as shown in FIG. 9, and the objective lens system OL has a front lens group G1, and forms an image. The lens system IL includes a rear lens group G2, a focusing lens group G4, and an imaging lens group G5. The rear lens group G2 includes a camera shake correction lens group G3.
　（表５）諸元表
FNO.＝14.578
f   ＝29.342
Ｙ  ＝17.000
Figure JPOXMLDOC01-appb-I000007

Figure JPOXMLDOC01-appb-I000008
（表６）可変間隔表
Figure JPOXMLDOC01-appb-I000009
(Table 5) Specifications
FNO. = 14.578
f = 29.342
Y = 17.000
Figure JPOXMLDOC01-appb-I000007

Figure JPOXMLDOC01-appb-I000008
(Table 6) Variable interval table
Figure JPOXMLDOC01-appb-I000009
　本発明による観察用光学系の実施例４を図面を参照して説明する。図１３は光学断面図、図１４,１５はそれぞれ遠距離物体合焦状態、近距離物体合焦状態での縦収差図である。表７,８はその数値データである。 Embodiment 4 of the observation optical system according to the present invention will be described with reference to the drawings. FIG. 13 is an optical cross-sectional view, and FIGS. 14 and 15 are longitudinal aberration diagrams in a long-distance object focusing state and a short-distance object focusing state, respectively. Tables 7 and 8 show the numerical data.
　実施例４の観察用光学系は、図１３に示すように物体側から順に、対物レンズ系ＯＬと結像レンズ系ＩＬとを備え、対物レンズ系ＯＬは前レンズ群Ｇ１を有し、結像レンズ系ＩＬは後レンズ群Ｇ２、合焦レンズ群Ｇ４、及び撮像レンズ群Ｇ５を有する。後レンズ群Ｇ２は、手振れ補正レンズ群Ｇ３を含む。 The observation optical system of Example 4 includes an objective lens system OL and an imaging lens system IL in order from the object side as shown in FIG. 13, and the objective lens system OL has a front lens group G1, and forms an image. The lens system IL includes a rear lens group G2, a focusing lens group G4, and an imaging lens group G5. The rear lens group G2 includes a camera shake correction lens group G3.
　（表７）諸元表
FNO.＝15.105
f   ＝27.531
Ｙ  ＝17.000
Figure JPOXMLDOC01-appb-I000010

Figure JPOXMLDOC01-appb-I000011
（表８）可変間隔表
Figure JPOXMLDOC01-appb-I000012
(Table 7) Specification table
FNO. = 15.105
f = 27.531
Y = 17.000
Figure JPOXMLDOC01-appb-I000010

Figure JPOXMLDOC01-appb-I000011
(Table 8) Variable interval table
Figure JPOXMLDOC01-appb-I000012
　本発明による観察用光学系の実施例５を図面を参照して説明する。図１７は光学断面図、図１８,１９はそれぞれ遠距離物体合焦状態、近距離物体合焦状態での縦収差図である。表９～１１はその数値データである。 Embodiment 5 of the observation optical system according to the present invention will be described with reference to the drawings. FIG. 17 is an optical cross-sectional view, and FIGS. 18 and 19 are longitudinal aberration diagrams in a long-distance object focusing state and a short-distance object focusing state, respectively. Tables 9 to 11 show the numerical data.
　実施例５の観察用光学系は、図１７に示すように物体側から順に、対物レンズ系ＯＬと結像レンズ系ＩＬとを備え、対物レンズ系ＯＬは前レンズ群Ｇ１を有し、結像レンズ系ＩＬは後レンズ群Ｇ２、及び合焦レンズ群Ｇ４を有する。すなわち、実施例５の観察用光学系は、実施例１～４の観察用光学系が備える撮像レンズ群Ｇ５に対応するレンズ群を有していない。なお、後レンズ群Ｇ２は、手振れ補正レンズ群Ｇ３を含む。 The observation optical system of Example 5 includes an objective lens system OL and an imaging lens system IL in order from the object side as shown in FIG. 17, and the objective lens system OL has a front lens group G1, and forms an image. The lens system IL includes a rear lens group G2 and a focusing lens group G4. That is, the observation optical system of Example 5 does not have a lens group corresponding to the imaging lens group G5 included in the observation optical systems of Examples 1 to 4. The rear lens group G2 includes a camera shake correction lens group G3.
　（表９）諸元表
FNO.＝12.223
f   ＝25.338
Ｙ  ＝14.200
Figure JPOXMLDOC01-appb-I000013

Figure JPOXMLDOC01-appb-I000014
　（表１０）非球面データ（表示していない非球面係数は0.00である。）
Figure JPOXMLDOC01-appb-I000015
（表１１）可変間隔表
Figure JPOXMLDOC01-appb-I000016
(Table 9) Specifications
FNO. = 12.223
f = 25.338
Y = 14.200
Figure JPOXMLDOC01-appb-I000013

Figure JPOXMLDOC01-appb-I000014
(Table 10) Aspheric data (Aspheric coefficient not shown is 0.00)
Figure JPOXMLDOC01-appb-I000015
(Table 11) Variable interval table
Figure JPOXMLDOC01-appb-I000016
　各実施例の観察用光学系において、手振れ補正状態での防振群の光軸と垂直な方向への移動量は全て０．３３０ｍｍである。また、その時の防振補正角は下記に記載の通りである。
実施例１　０．６０４度
実施例２　０．６０５度
実施例３　０．５８１度
実施例４　０．６２３度
実施例５　０．７２３度 In the observation optical system of each example, the amount of movement of the image stabilizing group in the direction perpendicular to the optical axis in the camera shake correction state is all 0.330 mm. Further, the image stabilization angle at that time is as described below.
Example 1 0.604 degree Example 2 0.605 degree Example 3 0.581 degree Example 4 0.623 degree Example 5 0.723 degree
　各実施例の請求項記載の数式に対応する条件式対応値を表１２に示す。
　（表１２）条件式対応値
Figure JPOXMLDOC01-appb-I000017
Table 12 shows values corresponding to the conditional expressions corresponding to the mathematical expressions described in the claims of the respective examples.
(Table 12) Values corresponding to conditional expressions
Figure JPOXMLDOC01-appb-I000017
　本発明に係る撮像装置の一実施例は、図２１の断面説明図に示すように、照明光源１０１から出射した照明光が、照明光路１０２を経由して被写体（図示せず）へ照射される。被写体で反射された被写体光は、対物レンズ系ＯＬによって空間中間結像ＩＭＧを形成する。空間中間結像ＩＭＧは、結像レンズ系ＩＬによって撮像装置１０５内の撮像素子１０６上に再結像する。撮像素子１０６から出力された撮像信号は表示装置１０７に入力され、表示装置１０７が被写体像を表示する。 In one embodiment of the imaging apparatus according to the present invention, as shown in the cross-sectional explanatory diagram of FIG. 21, illumination light emitted from the illumination light source 101 is irradiated to a subject (not shown) via the illumination light path 102. . The subject light reflected by the subject forms a spatial intermediate image IMG by the objective lens system OL. The spatial intermediate imaging IMG is re-imaged on the imaging element 106 in the imaging device 105 by the imaging lens system IL. The imaging signal output from the imaging element 106 is input to the display device 107, and the display device 107 displays the subject image.
ＩＭＧ　　　　　　　　　空間中間結像
ＯＬ　　　　　　　　　　対物レンズ系
ＩＬ　　　　　　　　　　結像レンズ系
Ｇ１　　　　　　　　　　前レンズ群
Ｇ２　　　　　　　　　　後レンズ群
Ｇ３　　　　　　　　　　手振れ補正レンズ群
Ｇ４　　　　　　　　　　合焦レンズ群
Ｇ５　　　　　　　　　　撮像レンズ群
１、２、３、・・・　　　レンズ面
１０１　　　　　　　　　照明光源
１０２　　　　　　　　　照明光路 
１０５　　　　　　　　　撮像装置
１０６　　　　　　　　　撮像素子
１０７　　　　　　　　　表示装置 IMG Spatial intermediate imaging OL Objective lens system IL Imaging lens system G1 Front lens group G2 Rear lens group G3 Camera shake correction lens group G4 Focusing lens group G5 Imaging lens groups 1, 2, 3,... Lens surface 101 Illumination light source 102 Illumination light path
105 Imaging device 106 Imaging element 107 Display device

Claims (8)

  1. 　物体側から順に、対物レンズと、結像レンズとを持ち、前記結像レンズ中に物体距離の変動に応じて光軸方向に移動させてフォーカシングさせるフォーカス群を具備し、前記対物レンズは被写体像を縮小して空間中間結像面に入射させ、前記結像レンズでは前記空間中間結像を拡大して撮像素子上に再結像させることを特徴とする観察用光学系。 In order from the object side, an objective lens and an imaging lens are provided, and the imaging lens includes a focus group that is moved in the optical axis direction according to a change in the object distance to perform focusing. The observation optical system is characterized in that the image is reduced and made incident on a spatial intermediate imaging plane, and the imaging lens enlarges the spatial intermediate imaging and re-images it on the image sensor.
  2. 　以下の条件式を満足することを特徴とする請求項１に記載の観察用光学系。
    （１） ０．０５０≦ ｆｏ／ｆｉ ≦１．１００
    ｆｏ：対物レンズの焦点距離
    ｆｉ：結像レンズの遠距離物体合焦状態での焦点距離     The observation optical system according to claim 1, wherein the following conditional expression is satisfied.
    (1) 0.050 ≦ fo / fi ≦ 1.100
    fo: focal length of the objective lens fi: focal length of the imaging lens in the state of focusing on a long distance object
  3. 　以下の条件式を満足することを特徴とする請求項１又は２に記載の観察用光学系。
    （２） ０．０００≦ ｂ１ｆ ≦０．１００
    （３） ３．０００≦ ｂ２ｆ ≦６．５００
    ただし、
    ｂ１ｆ：対物レンズの遠距離物体合焦状態での近軸横倍率の絶対値
    ｂ２ｆ：結像レンズの遠距離物体合焦状態での横倍率の絶対値     The observation optical system according to claim 1, wherein the following conditional expression is satisfied.
    (2) 0.000 ≦ b1f ≦ 0.100
    (3) 3.000 ≦ b2f ≦ 6,500
    However,
    b1f: absolute value of paraxial lateral magnification when the objective lens is in focus with a long distance object b2f: absolute value of lateral magnification when the imaging lens is in focus with a long distance object
  4. 　以下の条件式を満足することを特徴とする請求項１から３のいずれか一項に記載の観察用光学系。
    （４） ０．２９０≦(ｂ１ｆ×ｂ２ｆ)／(ｂ１ｎ×ｂ２ｎ)≦０．４７０
    　ただし、
    ｂ１ｎ：対物レンズの近距離物体合焦状態での横倍率の絶対値
    ｂ２ｎ：結像レンズの近距離物体合焦状態での横倍率の絶対値     The observation optical system according to any one of claims 1 to 3, wherein the following conditional expression is satisfied.
    (4) 0.290 ≦ (b1f × b2f) / (b1n × b2n) ≦ 0.470
    However,
    b1n: Absolute value of the lateral magnification when the objective lens is focused on a short distance object b2n: Absolute value of the lateral magnification when the imaging lens is focused on a short distance object
  5. 　以下の条件式を満足することを特徴とする請求項１から４のいずれか一項に記載の観察用光学系。
    （５） ０．８００≦ＴａｎＷｆ／ＴａｎＷｎ≦１．４００
    　ただし、
    Ｗｆ：遠距離物体合焦状態での半画角
    Ｗｎ：近距離物体合焦状態での半画角     The observation optical system according to claim 1, wherein the following conditional expression is satisfied.
    (5) 0.800 ≦ TanWf / TanWn ≦ 1.400
    However,
    Wf: Half field angle in the state of focusing on a long distance object Wn: Half field angle in the state of focusing on a short distance object
  6. 　前記第一レンズ群内に、光軸に対して垂直に移動させて手振れ補正を行う防振レンズ群を具備し、以下の条件式を満足することを特徴とする請求項１から５のいずれか一項に記載の観察用光学系。
    （６） ０．７００≦ｆｖ／ｆ≦１．３００
    　ただし、
    ｆｖ：防振群の焦点距離
    ｆ：全系の焦点距離の絶対値     6. The anti-vibration lens group that performs a camera shake correction by moving the first lens group perpendicularly to the optical axis, and satisfies the following conditional expression: 6. The observation optical system according to one item.
    (6) 0.700 ≦ fv / f ≦ 1.300
    However,
    fv: Focal length of the anti-vibration group f: Absolute value of the focal length of the entire system
  7. 　前記対物レンズが、対称型レンズ部を有することを特徴とする請求項１から６のいずれか一項に記載の観察用光学系。 The observation optical system according to any one of claims 1 to 6, wherein the objective lens has a symmetric lens portion.
  8. 　請求項１から７のいずれか一項に記載の観察用光学系と、形成された光学像を電気的信号に変換する撮像素子とを備えたことを特徴とする撮像装置。 An imaging apparatus comprising: the observation optical system according to any one of claims 1 to 7; and an imaging device that converts the formed optical image into an electrical signal.
PCT/JP2015/085835 2015-01-16 2015-12-22 Optical system for observation and imaging device provided with same WO2016114081A1 (en)

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