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WO2020174561A1 - Système optique d'objectif d'endoscope - Google Patents

Système optique d'objectif d'endoscope Download PDF

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Publication number
WO2020174561A1
WO2020174561A1 PCT/JP2019/007205 JP2019007205W WO2020174561A1 WO 2020174561 A1 WO2020174561 A1 WO 2020174561A1 JP 2019007205 W JP2019007205 W JP 2019007205W WO 2020174561 A1 WO2020174561 A1 WO 2020174561A1
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Prior art keywords
lens
observation state
optical system
objective optical
lens group
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PCT/JP2019/007205
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English (en)
Japanese (ja)
Inventor
辻善文
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Olympus Corp
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Olympus Corp
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Priority to PCT/JP2019/007205 priority Critical patent/WO2020174561A1/fr
Priority to JP2021501416A priority patent/JP7079892B2/ja
Publication of WO2020174561A1 publication Critical patent/WO2020174561A1/fr
Anticipated expiration legal-status Critical
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/04—Reversed telephoto objectives

Definitions

  • the present invention relates to an objective optical system.
  • the present invention relates to an objective optical system (imaging optical system) for an endoscope, and can be used for an endoscope device used in, for example, the medical field or industrial field.
  • the endoscope is a device widely used in the medical field and the industrial field. Particularly in the medical field, from the viewpoint of reducing the burden on patients and improving the diagnostic accuracy, downsizing and high pixel number of imaging devices of endoscopes, such as CCDs and CMOSs, have been advanced.
  • the endoscope objective optical system is also required to have a wide observation depth from the far point to the near point while satisfying optical performance such as widening of the angle and correction of aberrations.
  • the F number (Fno) of the objective optical system is preferably in the following range so as not to be affected by light diffraction. Fno ⁇ 2 ⁇ P/1.22/ ⁇
  • P is the pixel pitch of the image sensor.
  • the optical performance will deteriorate due to diffraction. Therefore, by reducing the F number of the optical system, it is possible to avoid the influence of diffraction. However, if the F number of the optical system is reduced, the observation depth becomes shallow.
  • each component is fixed by a mechanical member. At this time, it is necessary to fix the mechanical member with an adhesive.
  • the above-mentioned endoscope objective optical system may not be applicable to observation due to the influence of diffraction caused by miniaturization and the deterioration of optical performance due to manufacturing variations.
  • the zoom objective optical systems of Patent Documents 1 and 2 are small in size, but have optical specifications with a large F number. For this reason, in a recent situation where the pixel pitch is small due to the downsizing of the image sensor and the increase in the number of pixels, the optical performance is deteriorated due to the influence of diffraction. Further, the zoom objective optical systems of Patent Documents 1 and 2 cannot be applied to good observation because the problem of manufacturing variations is not taken into consideration.
  • the present invention has been made in view of such problems, and it is possible to perform magnifying observation (near-point observation) according to a change in the object distance, and it is possible to secure a sufficient observation depth with a small size and a wide-angle visual field. It is an object of the present invention to provide a high-performance objective optical system for an endoscope, which has a corner, and in which the optical aberration is well corrected from the center of the screen to the peripheral portion, and the observation and diagnosis of the lesion are easy.
  • an objective optical system for an endoscope includes a positive first lens group and a negative first lens group in order from the object side.
  • the first lens group is composed of only two lens groups and a positive third lens group, and the first lens group comprises, in order from the object side, a first lens composed of a negative single lens and a second lens composed of a negative single lens.
  • the second lens group performs focusing and zooming by moving on the optical axis
  • the third lens group includes a cemented lens and an image sensor or a cover glass formed on the image sensor. And a positive single lens that is cemented.
  • the magnified observation state will be referred to as the "near-point observation state”.
  • the normal observation state is appropriately referred to as “at the time of focusing on a long-distance object point”.
  • magied observation near point observation
  • FIG. 3A is a lens cross-sectional view of the endoscope objective optical system according to the embodiment in a normal observation state.
  • FIG. 3B is a lens cross-sectional view of the endoscope objective optical system according to the embodiment in a magnified observation state.
  • 3A is a lens cross-sectional view of an endoscope objective optical system according to Example 1 in a normal observation state.
  • FIG. 3B is a lens cross-sectional view of the endoscope objective optical system according to Example 1 in a magnified observation state.
  • (a) is a spherical aberration (SA) in a normal observation state
  • (b) is an astigmatism (AS) in a normal observation state
  • (c) is a normal observation state.
  • Distortion aberrations (DT) and (d) in FIG. 3 indicate lateral chromatic aberration (CC) in a normal observation state.
  • (e) is spherical aberration (SA) in the magnified observation state
  • (f) is astigmatism (AS) in the magnified observation state
  • (g) is distortion aberration (DT) in the magnified observation state
  • (h) is magnified.
  • the chromatic aberration of magnification (CC) in the observation state is shown.
  • FIG. 7A is a lens cross-sectional view of an endoscope objective optical system according to Example 2 in a normal observation state.
  • FIG. 6B is a lens cross-sectional view of the endoscope objective optical system according to Example 2 in a magnified observation state.
  • SA spherical aberration
  • AS astigmatism
  • DT Distortion aberrations
  • DT lateral chromatic aberration
  • CC lateral chromatic aberration
  • SA spherical aberration
  • AS astigmatism
  • DT distortion aberration
  • CC chromatic aberration of magnification
  • a is a spherical aberration (SA) in a normal observation state
  • (b) is an astigmatism (AS) in a normal observation state
  • (c) is a normal observation state.
  • Distortion aberrations (DT) and (d) in FIG. 3 indicate lateral chromatic aberration (CC) in a normal observation state.
  • (e) is spherical aberration (SA) in the magnified observation state
  • (f) is astigmatism (AS) in the magnified observation state
  • g) is distortion aberration (DT) in the magnified observation state
  • (h) is magnified.
  • the chromatic aberration of magnification (CC) in the observation state is shown.
  • FIG. 7A is a lens cross-sectional view of an endoscope objective optical system according to Example 4 in a normal observation state.
  • FIG. 7B is a lens cross-sectional view of the endoscope objective optical system according to Example 4 in a magnified observation state.
  • SA spherical aberration
  • AS astigmatism
  • DT Distortion aberrations
  • DT lateral chromatic aberration
  • SA spherical aberration
  • AS astigmatism
  • DT distortion aberration
  • CC chromatic aberration of magnification
  • a is a spherical aberration (SA) in a normal observation state
  • (b) is an astigmatism (AS) in a normal observation state
  • (c) is a normal observation state.
  • Distortion aberrations (DT) and (d) in FIG. 3 indicate lateral chromatic aberration (CC) in a normal observation state.
  • (e) is spherical aberration (SA) in the magnified observation state
  • (f) is astigmatism (AS) in the magnified observation state
  • g) is distortion aberration (DT) in the magnified observation state
  • (h) is magnified.
  • the chromatic aberration of magnification (CC) in the observation state is shown.
  • FIG. 16A is a lens cross-sectional view of an endoscope objective optical system according to Example 6 in a normal observation state.
  • FIG. FIG. 7B is a lens cross-sectional view of the endoscope objective optical system according to Example 6 in a magnified observation state.
  • SA spherical aberration
  • AS astigmatism
  • DT Distortion aberrations
  • DT lateral chromatic aberration
  • CC lateral chromatic aberration
  • SA spherical aberration
  • AS astigmatism
  • DT distortion aberration
  • CC chromatic aberration of magnification
  • (a) is a spherical aberration (SA) in a normal observation state
  • (b) is an astigmatism (AS) in a normal observation state
  • (c) is a normal observation state.
  • Distortion aberrations (DT) and (d) in FIG. 3 indicate lateral chromatic aberration (CC) in a normal observation state.
  • (e) is spherical aberration (SA) in the magnified observation state
  • (f) is astigmatism (AS) in the magnified observation state
  • (g) is distortion aberration (DT) in the magnified observation state
  • (h) is magnified.
  • the chromatic aberration of magnification (CC) in the observation state is shown.
  • FIG. 9A is a lens cross-sectional view of an endoscope objective optical system according to Example 8 in a normal observation state.
  • 9B is a lens cross-sectional view of an endoscope objective optical system according to Example 8 in a magnified observation state.
  • SA spherical aberration
  • AS astigmatism
  • DT Distortion aberrations
  • DT lateral chromatic aberration
  • CC lateral chromatic aberration
  • FIG. 16A is a lens cross-sectional view of an endoscope objective optical system according to Example 9 in a normal observation state.
  • FIG. 16B is a lens cross-sectional view of the endoscope objective optical system according to Example 9 in a magnified observation state.
  • (a) is a spherical aberration (SA) in a normal observation state
  • (b) is an astigmatism (AS) in a normal observation state
  • (c) is a normal observation state.
  • Distortion aberrations (DT) and (d) in FIG. 3 indicate lateral chromatic aberration (CC) in a normal observation state.
  • (e) is spherical aberration (SA) in the magnified observation state
  • (f) is astigmatism (AS) in the magnified observation state
  • (g) is distortion aberration (DT) in the magnified observation state
  • (h) is magnified.
  • the chromatic aberration of magnification (CC) in the observation state is shown.
  • FIG. 13A is a lens cross-sectional view of an endoscope objective optical system according to Example 10 in a normal observation state.
  • (B) is a lens cross-sectional view of an endoscope objective optical system according to Example 10 in a magnified observation state.
  • SA spherical aberration
  • AS astigmatism
  • DT Distortion aberrations
  • DT lateral chromatic aberration
  • CC lateral chromatic aberration
  • SA spherical aberration
  • AS astigmatism
  • DT distortion aberration
  • CC chromatic aberration of magnification
  • (a) is a spherical aberration (SA) in a normal observation state
  • (b) is an astigmatism (AS) in a normal observation state
  • (c) is a normal observation state.
  • Distortion aberrations (DT) and (d) in FIG. 3 indicate lateral chromatic aberration (CC) in a normal observation state.
  • (e) is spherical aberration (SA) in the magnified observation state
  • (f) is astigmatism (AS) in the magnified observation state
  • (g) is distortion aberration (DT) in the magnified observation state
  • (h) is magnified.
  • the chromatic aberration of magnification (CC) in the observation state is shown.
  • FIG. 1A is a lens cross-sectional view of the endoscope objective optical system according to the embodiment in a normal observation state.
  • FIG. 3B is a lens cross-sectional view of the endoscope objective optical system according to the embodiment in a magnified observation state.
  • the present embodiment is composed of only a positive first lens group G1, a negative second lens group G2, and a positive third lens group G3 in order from the object side.
  • the first lens group G1 is an object. In order from the side, it has a first lens L1 composed of a negative single lens and a second lens L2 composed of a negative single lens, and the second lens group G2 is focused by moving on the optical axis AX.
  • the third lens group G3 includes a cemented lens CL and a positive single lens L11 cemented to the image sensor IMG or a cover glass CG formed on the image sensor IMG.
  • the objective optical system for an endoscope of this embodiment is a bright optical system with a small F number. Therefore, as described above, in general, the optical performance is greatly deteriorated due to manufacturing variations. Further, the first lens L1 closest to the object side requires a relatively strong negative refractive power for downsizing and widening the angle.
  • the lens eccentricity occurs due to manufacturing variations. Due to the eccentricity of the lens, the image quality around the image is greatly deteriorated. Therefore, in the first lens group G1, the second lens L2 formed of a negative single lens is arranged on the image side of the first lens L1. As a result, it is possible to disperse the power (refractive power) and suppress deterioration of the peripheral image quality due to lens decentering.
  • the third lens group G3 has a positive single lens L11.
  • the positive single lens L11 is joined to the image sensor IMG.
  • the positive single lens L11 is joined to the cover glass CG formed on the image sensor IMG.
  • the F number is bright, the wide angle is small, the size is small (small diameter), and high-definition image quality can be obtained up to the periphery of the imaging area. It is possible to provide an objective optical system for an endoscope.
  • F12 is a combined focal length of the first lens L1 and the second lens L2
  • Fim is the focal length of the positive single lens L11, Is.
  • Conditional expression (1) defines an appropriate ratio between Fim and F12. If the upper limit of conditional expression (1) is exceeded, astigmatism will deteriorate. In particular, when magnifying and observing, the peripheral image quality of the screen is greatly deteriorated. When the value goes below the lower limit of the conditional expression (1), coma is deteriorated or the sensitivity of focus position shift is increased. Therefore, it is not possible to obtain high-definition image quality with a small optical system.
  • conditional expression (1′) is satisfied instead of conditional expression (1).
  • conditional expression (2) it is preferable that the following conditional expression (2) is satisfied.
  • FG3v is the focal length of the cemented lens CL of the third lens group G3
  • Fim is the focal length of the positive single lens L11, Is.
  • Conditional expression (2) defines an appropriate ratio between FG3v and Fim.
  • the positive single lens L11 is arranged in the third lens group G3.
  • the positive single lens L11 is joined to the image sensor IMG or the cover glass CG formed on the image sensor IMG.
  • the cemented lens CL is arranged to correct chromatic aberration.
  • the positive single lens L11 plays an important role in reducing the sensitivity of focus position shift. Furthermore, the positive single lens L11 also contributes to the height of the marginal ray of the cemented lens CL of the third lens group G3.
  • conditional expression (2) If the upper limit of conditional expression (2) is exceeded, the chromatic aberration of magnification will deteriorate or the lens diameter will increase. Therefore, it is difficult to reduce the size of the optical system. Moreover, it becomes impossible to obtain high-definition image quality in a small objective optical system. It does not fall below the lower limit of conditional expression (2).
  • conditional expression (2′) is satisfied instead of conditional expression (2). 0 ⁇
  • FG2 is a focal length of the second lens group G2
  • F is the focal length of the entire objective optical system for an endoscope when focusing on a long-distance object point, Is.
  • Conditional expression (3) defines an appropriate ratio between FG2 and F.
  • the focal lengths of the second lens group G2 and the entire objective optical system for an endoscope when focusing on a long-distance object point are conditional expressions. It is necessary to optimize by (3).
  • conditional expression (3) If the upper limit of conditional expression (3) is exceeded, the amount of astigmatism generated will increase. When the value goes below the lower limit of conditional expression (3), the image plane falls over and the peripheral image quality deteriorates significantly. Therefore, it becomes impossible to obtain high-definition image quality with a small optical system.
  • conditional expression (3′) is satisfied instead of conditional expression (3).
  • FIG. 2A is a lens cross-sectional view of the endoscope objective optical system according to Example 1 in a normal observation state.
  • FIG. 2B is a lens cross-sectional view of the endoscope objective optical system according to Example 1 in a magnified observation state.
  • the objective optical system for an endoscope is composed of only 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 G3 having a positive refractive power in order from the object side. To be done.
  • the first lens group G1 includes, in order from the object side, a plano-concave negative lens L1 having a plane facing the object side, a biconcave negative lens L2, an infrared cut filter F that is a parallel plate, and a biconvex positive lens L3. , A biconvex positive lens L4, and a negative meniscus lens L5 having a convex surface facing the image side.
  • the positive lens L4 and the negative meniscus lens L5 are cemented.
  • the second lens group G2 includes a negative meniscus lens L6 having a convex surface directed toward the object side and a positive meniscus lens L7 having a convex surface directed toward the object side.
  • the negative meniscus lens L6 and the positive meniscus lens L7 are cemented.
  • the cemented lens performs focusing and zooming by moving on the optical axis AX.
  • An aperture stop S is arranged between the first lens group G1 and the second lens group G2.
  • the aperture stop S moves together with the second lens group G2.
  • the third lens group G3 includes a plano-convex positive lens L8 having a plane directed to the image side, a biconvex positive lens L9, a biconcave negative lens L10, and a plano-convex positive lens L11 having a plane directed to the image side.
  • the positive lens L9 and the negative lens L10 are cemented to form a cemented lens CL.
  • the plano-convex positive lens L11 is joined to the image sensor IMG via a cover glass CG formed on the image sensor IMG. Further, the plano-convex positive lens L11 may be joined to the image sensor IMG.
  • a is a spherical aberration (SA) in a normal observation state
  • (b) is an astigmatism (AS) in a normal observation state
  • (c) Indicates distortion aberration (DT) in the normal observation state
  • (d) indicates lateral chromatic aberration (CC) in the normal observation state
  • (e) is spherical aberration (SA) in the magnified observation state
  • (f) is astigmatism (AS) in the magnified observation state
  • g) is distortion aberration (DT) in the magnified observation state
  • (h) is magnified.
  • the chromatic aberration of magnification (CC) in the observation state is shown.
  • the objective optical system for an endoscope according to the present embodiment has little fluctuation in the F number from the normal observation state to the magnified observation state. Therefore, an appropriate depth of field is secured without being affected by diffraction in the optical system in each state.
  • the horizontal axis represents the amount of aberration.
  • the unit of the amount of aberration is mm.
  • the unit of the amount of aberration is %.
  • FIY is the image height in mm
  • FNO is the F number.
  • the unit of wavelength of the aberration curve is nm.
  • FIG. 4A is a lens cross-sectional view of the endoscope objective optical system according to the second embodiment in a normal observation state.
  • FIG. 4B is a lens cross-sectional view of the endoscope objective optical system according to the second embodiment in a magnified observation state.
  • the objective optical system for an endoscope is composed of only 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 G3 having a positive refractive power in order from the object side. To be done.
  • the first lens group G1 includes, in order from the object side, a plano-concave negative lens L1 having a flat surface facing the object side, a negative meniscus lens L2 having a convex surface facing the object side, and an infrared cut filter F that is a parallel plate. It has a positive meniscus lens L3 having a convex surface facing the image side, a biconvex positive lens L4, and a negative meniscus lens L5 having a convex surface facing the image side.
  • the positive lens L4 and the negative meniscus lens L5 are cemented.
  • the second lens group G2 includes a negative meniscus lens L6 having a convex surface directed toward the object side and a positive meniscus lens L7 having a convex surface directed toward the object side.
  • the negative meniscus lens L6 and the positive meniscus lens L7 are cemented.
  • the cemented lens performs focusing and zooming by moving on the optical axis AX.
  • An aperture stop S is arranged between the first lens group G1 and the second lens group G2.
  • the aperture stop S moves together with the second lens group G2.
  • the third lens group G3 includes a biconvex positive lens L8, a biconvex positive lens L9, a biconcave negative lens L10, and a plano-convex positive lens L11 having a plane facing the image side.
  • the positive lens L9 and the negative lens L10 are cemented to form a cemented lens CL.
  • the plano-convex positive lens L11 is joined to the image sensor IMG via a cover glass CG formed on the image sensor IMG. Further, the plano-convex positive lens L11 may be joined to the image sensor IMG.
  • a is a spherical aberration (SA) in a normal observation state
  • (b) is an astigmatism (AS) in a normal observation state
  • (c) Indicates distortion aberration (DT) in the normal observation state
  • (d) indicates lateral chromatic aberration (CC) in the normal observation state
  • (e) is spherical aberration (SA) in the magnified observation state
  • (f) is astigmatism (AS) in the magnified observation state
  • g) is distortion aberration (DT) in the magnified observation state
  • (h) is magnified.
  • the chromatic aberration of magnification (CC) in the observation state is shown.
  • the objective optical system for an endoscope according to the present embodiment has little fluctuation in the F number from the normal observation state to the magnified observation state. Therefore, an appropriate depth of field is secured without being affected by diffraction in the optical system in each state.
  • FIG. 6A is a lens cross-sectional view of the objective optical system for an endoscope according to Example 3 in a normal observation state.
  • FIG. 6B is a lens cross-sectional view of the endoscope objective optical system according to Example 3 in a magnified observation state.
  • the objective optical system for an endoscope is composed of only 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 G3 having a positive refractive power in order from the object side. To be done.
  • the first lens group G1 includes, in order from the object side, a plano-concave negative lens L1 having a flat surface facing the object side, a biconcave negative lens L2, an infrared cut filter F that is a parallel plate, and a flat surface facing the object side. And a plano-convex positive lens L3, a biconvex positive lens L4, and a negative meniscus lens L5 having a convex surface directed toward the image side.
  • the positive lens L4 and the negative meniscus lens L5 are cemented.
  • the second lens group G2 includes a negative meniscus lens L6 having a convex surface directed toward the object side and a positive meniscus lens L7 having a convex surface directed toward the object side.
  • the negative meniscus lens L6 and the positive meniscus lens L7 are cemented.
  • the cemented lens performs focusing and zooming by moving on the optical axis AX.
  • An aperture stop S is arranged between the first lens group G1 and the second lens group G2.
  • the aperture stop S moves together with the second lens group G2.
  • the third lens group G3 includes a plano-convex positive lens L8 whose plane faces the image side, a biconvex positive lens L9, a biconcave negative lens L10, and a plano-convex positive lens L11 whose plane faces the image side.
  • the positive lens L9 and the negative lens L10 are cemented to form a cemented lens CL.
  • the plano-convex positive lens L11 is joined to the image sensor IMG via a cover glass CG formed on the image sensor IMG. Further, the plano-convex positive lens L11 may be joined to the image sensor IMG.
  • a is a spherical aberration (SA) in a normal observation state
  • (b) is an astigmatism (AS) in a normal observation state
  • (c) Indicates distortion aberration (DT) in the normal observation state
  • (d) indicates lateral chromatic aberration (CC) in the normal observation state
  • (e) is spherical aberration (SA) in the magnified observation state
  • (f) is astigmatism (AS) in the magnified observation state
  • g) is distortion aberration (DT) in the magnified observation state
  • (h) is magnified.
  • the chromatic aberration of magnification (CC) in the observation state is shown.
  • the objective optical system for an endoscope according to the present embodiment has little fluctuation in the F number from the normal observation state to the magnified observation state. Therefore, an appropriate depth of field is secured without being affected by diffraction in the optical system in each state.
  • FIG. 8A is a lens cross-sectional view of the endoscope objective optical system according to Example 4 in a normal observation state.
  • FIG. 8B is a lens cross-sectional view of the endoscope objective optical system according to Example 4 in a magnified observation state.
  • the objective optical system for an endoscope is composed of only 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 G3 having a positive refractive power in order from the object side. To be done.
  • the first lens group G1 includes, in order from the object side, a plano-concave negative lens L1 having a flat surface facing the object side, a negative meniscus lens L2 having a convex surface facing the object side, and an infrared cut filter F that is a parallel plate. It has a positive meniscus lens L3 having a convex surface facing the image side, a biconvex positive lens L4, and a negative meniscus lens L5 having a convex surface facing the image side.
  • the positive lens L4 and the negative meniscus lens L5 are cemented.
  • the second lens group G2 includes a negative meniscus lens L6 having a convex surface directed toward the object side and a negative meniscus lens L7 having a convex surface directed toward the object side.
  • the negative meniscus lens L6 and the negative meniscus lens L7 are cemented.
  • the cemented lens performs focusing and zooming by moving on the optical axis AX.
  • An aperture stop S is arranged between the first lens group G1 and the second lens group G2.
  • the aperture stop S moves together with the second lens group G2.
  • the third lens group G3 includes a biconvex positive lens L8, a biconvex positive lens L9, a biconcave negative lens L10, and a plano-convex positive lens L11 having a plane facing the image side.
  • the positive lens L9 and the negative lens L10 are cemented to form a cemented lens CL.
  • the plano-convex positive lens L11 is joined to the image sensor IMG via a cover glass CG formed on the image sensor IMG. Further, the plano-convex positive lens L11 may be joined to the image sensor IMG.
  • a is a spherical aberration (SA) in a normal observation state
  • (b) is an astigmatism (AS) in a normal observation state
  • (c) Indicates distortion aberration (DT) in the normal observation state
  • (d) indicates lateral chromatic aberration (CC) in the normal observation state
  • (e) is spherical aberration (SA) in the magnified observation state
  • (f) is astigmatism (AS) in the magnified observation state
  • g) is distortion aberration (DT) in the magnified observation state
  • (h) is magnified.
  • the chromatic aberration of magnification (CC) in the observation state is shown.
  • the objective optical system for an endoscope according to the present embodiment has little fluctuation in the F number from the normal observation state to the magnified observation state. Therefore, an appropriate depth of field is secured without being affected by diffraction in the optical system in each state.
  • FIG. 10A is a lens cross-sectional view of the endoscope objective optical system according to Example 5 in a normal observation state.
  • FIG. 10B is a lens cross-sectional view of the endoscope objective optical system according to Example 5 in a magnified observation state.
  • the objective optical system for an endoscope is composed of only 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 G3 having a positive refractive power in order from the object side. To be done.
  • the first lens group G1 includes, in order from the object side, a plano-concave negative lens L1 having a plane facing the object side, a biconcave negative lens L2, an infrared cut filter F that is a parallel plate, and a biconvex positive lens L3. , A biconvex positive lens L4, and a negative meniscus lens L5 having a convex surface facing the image side.
  • the positive lens L4 and the negative meniscus lens L5 are cemented.
  • the second lens group G2 includes a negative meniscus lens L6 having a convex surface directed toward the object side and a positive meniscus lens L7 having a convex surface directed toward the object side.
  • the negative meniscus lens L6 and the positive meniscus lens L7 are cemented.
  • the cemented lens performs focusing and zooming by moving on the optical axis AX.
  • An aperture stop S is arranged between the first lens group G1 and the second lens group G2.
  • the aperture stop S moves together with the second lens group G2.
  • the third lens group G3 includes a plano-convex positive lens L8 having a plane directed to the image side, a biconvex positive lens L9, a biconcave negative lens L10, and a plano-convex positive lens L11 having a plane directed to the image side.
  • the positive lens L9 and the negative lens L10 are cemented to form a cemented lens CL.
  • the plano-convex positive lens L11 is joined to the image sensor IMG via a cover glass CG formed on the image sensor IMG. Further, the plano-convex positive lens L11 may be joined to the image sensor IMG.
  • FIG. 11A and 11B show, in the objective optical system for an endoscope according to Example 5, (a) is a spherical aberration (SA) in a normal observation state, and (b) is an astigmatism (AS) in a normal observation state. Indicates distortion aberration (DT) in the normal observation state, and (d) indicates lateral chromatic aberration (CC) in the normal observation state. Further, (e) is spherical aberration (SA) in the magnified observation state, (f) is astigmatism (AS) in the magnified observation state, (g) is distortion aberration (DT) in the magnified observation state, and (h) is magnified. The chromatic aberration of magnification (CC) in the observation state is shown.
  • SA spherical aberration
  • AS astigmatism
  • CC distortion aberration
  • the objective optical system for an endoscope according to the present embodiment has little fluctuation in the F number from the normal observation state to the magnified observation state. Therefore, an appropriate depth of field is secured without being affected by diffraction in the optical system in each state.
  • FIG. 12A is a lens sectional view of the endoscope objective optical system according to Example 6 in a normal observation state.
  • FIG. 12B is a lens cross-sectional view of the endoscope objective optical system according to Example 6 in a magnified observation state.
  • the objective optical system for an endoscope is composed of only 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 G3 having a positive refractive power in order from the object side. To be done.
  • the first lens group G1 includes, in order from the object side, a plano-concave negative lens L1 having a plane facing the object side, a biconcave negative lens L2, an infrared cut filter F that is a parallel plate, and a biconvex positive lens L3. , A biconvex positive lens L4, and a negative meniscus lens L5 having a convex surface facing the image side.
  • the positive lens L4 and the negative meniscus lens L5 are cemented.
  • the second lens group G2 includes a negative meniscus lens L6 having a convex surface directed toward the object side and a positive meniscus lens L7 having a convex surface directed toward the object side.
  • the negative meniscus lens L6 and the positive meniscus lens L7 are cemented.
  • the cemented lens performs focusing and zooming by moving on the optical axis AX.
  • An aperture stop S is arranged between the first lens group G1 and the second lens group G2.
  • the aperture stop S moves together with the second lens group G2.
  • the third lens group G3 includes a plano-convex positive lens L8 whose plane faces the image side, a biconvex positive lens L9, a biconcave negative lens L10, and a plano-convex positive lens L11 whose plane faces the image side.
  • the positive lens L9 and the negative lens L10 are cemented to form a cemented lens CL.
  • the plano-convex positive lens L11 is joined to the image sensor IMG via a cover glass CG formed on the image sensor IMG. Further, the plano-convex positive lens L11 may be joined to the image sensor IMG.
  • SA spherical aberration
  • AS astigmatism
  • DT lateral chromatic aberration
  • CC chromatic aberration
  • the objective optical system for an endoscope according to the present embodiment has little fluctuation in the F number from the normal observation state to the magnified observation state. Therefore, an appropriate depth of field is secured without being affected by diffraction in the optical system in each state.
  • FIG. 14A is a lens cross-sectional view of the endoscope objective optical system according to Example 7 in a normal observation state.
  • FIG. 14B is a lens cross-sectional view of the endoscope objective optical system according to Example 7 in a magnified observation state.
  • the objective optical system for an endoscope is composed of only 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 G3 having a positive refractive power in order from the object side. To be done.
  • the first lens group G1 includes, in order from the object side, a plano-concave negative lens L1 having a plane facing the object side, a biconcave negative lens L2, an infrared cut filter F that is a parallel plate, and a biconvex positive lens L3. , A biconvex positive lens L4, and a negative meniscus lens L5 having a convex surface facing the image side.
  • the positive lens L4 and the negative meniscus lens L5 are cemented.
  • the second lens group G2 includes a negative meniscus lens L6 having a convex surface directed toward the object side and a positive meniscus lens L7 having a convex surface directed toward the object side.
  • the negative meniscus lens L6 and the positive meniscus lens L7 are cemented.
  • the cemented lens performs focusing and zooming by moving on the optical axis AX.
  • An aperture stop S is arranged between the first lens group G1 and the second lens group G2.
  • the aperture stop S moves together with the second lens group G2.
  • the third lens group G3 includes a plano-convex positive lens L8 having a plane directed to the image side, a biconvex positive lens L9, a biconcave negative lens L10, and a plano-convex positive lens L11 having a plane directed to the image side.
  • the positive lens L9 and the negative lens L10 are cemented to form a cemented lens CL.
  • the plano-convex positive lens L11 is joined to the image sensor IMG via a cover glass CG formed on the image sensor IMG. Further, the plano-convex positive lens L11 may be joined to the image sensor IMG.
  • a is a spherical aberration (SA) in a normal observation state
  • (b) is an astigmatism (AS) in a normal observation state
  • (c) Indicates distortion aberration (DT) in the normal observation state
  • (d) indicates lateral chromatic aberration (CC) in the normal observation state
  • (e) is spherical aberration (SA) in the magnified observation state
  • (f) is astigmatism (AS) in the magnified observation state
  • g) is distortion aberration (DT) in the magnified observation state
  • (h) is magnified.
  • the chromatic aberration of magnification (CC) in the observation state is shown.
  • the objective optical system for an endoscope according to the present embodiment has little fluctuation in the F number from the normal observation state to the magnified observation state. Therefore, an appropriate depth of field is secured without being affected by diffraction in the optical system in each state.
  • FIG. 16A is a lens cross-sectional view of the endoscope objective optical system according to Example 8 in a normal observation state.
  • FIG. 16B is a lens cross-sectional view of the endoscope objective optical system according to Example 8 in a magnified observation state.
  • the objective optical system for an endoscope is composed of only 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 G3 having a positive refractive power in order from the object side. To be done.
  • the first lens group G1 includes, in order from the object side, a plano-concave negative lens L1 having a flat surface facing the object side, a biconcave negative lens L2, an infrared cut filter F that is a parallel plate, and a flat surface facing the object side. And a plano-convex positive lens L3, a biconvex positive lens L4, and a negative meniscus lens L5 having a convex surface directed toward the image side.
  • the positive lens L4 and the negative meniscus lens L5 are cemented.
  • the second lens group G2 includes a negative meniscus lens L6 having a convex surface directed toward the object side and a positive meniscus lens L7 having a convex surface directed toward the object side.
  • the negative meniscus lens L6 and the positive meniscus lens L7 are cemented.
  • the cemented lens performs focusing and zooming by moving on the optical axis AX.
  • An aperture stop S is arranged between the first lens group G1 and the second lens group G2.
  • the aperture stop S moves together with the second lens group G2.
  • the third lens group G3 includes a plano-convex positive lens L8 having a plane directed to the image side, a biconvex positive lens L9, a biconcave negative lens L10, and a plano-convex positive lens L11 having a plane directed to the image side.
  • the positive lens L9 and the negative lens L10 are cemented to form a cemented lens CL.
  • the plano-convex positive lens L11 is joined to the image sensor IMG via a cover glass CG formed on the image sensor IMG. Further, the plano-convex positive lens L11 may be joined to the image sensor IMG.
  • a is a spherical aberration (SA) in a normal observation state
  • (b) is an astigmatism (AS) in a normal observation state
  • (c) Indicates distortion aberration (DT) in the normal observation state
  • (d) indicates lateral chromatic aberration (CC) in the normal observation state
  • (e) is spherical aberration (SA) in the magnified observation state
  • (f) is astigmatism (AS) in the magnified observation state
  • g) is distortion aberration (DT) in the magnified observation state
  • (h) is magnified.
  • the chromatic aberration of magnification (CC) in the observation state is shown.
  • the objective optical system for an endoscope according to the present embodiment has little fluctuation in the F number from the normal observation state to the magnified observation state. Therefore, an appropriate depth of field is secured without being affected by diffraction in the optical system in each state.
  • FIG. 18A is a lens sectional view of the endoscope objective optical system according to Example 9 in a normal observation state.
  • FIG. 18B is a lens cross-sectional view of the endoscope objective optical system according to Example 9 in a magnified observation state.
  • the objective optical system for an endoscope is composed of only 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 G3 having a positive refractive power in order from the object side. To be done.
  • the first lens group G1 includes, in order from the object side, a plano-concave negative lens L1 having a flat surface facing the object side, a biconcave negative lens L2, an infrared cut filter F that is a parallel plate, and a flat surface facing the object side. And a plano-convex positive lens L3, a biconvex positive lens L4, and a negative meniscus lens L5 having a convex surface directed toward the image side.
  • the positive lens L4 and the negative meniscus lens L5 are cemented.
  • the second lens group G2 includes a negative meniscus lens L6 having a convex surface directed toward the object side and a positive meniscus lens L7 having a convex surface directed toward the object side.
  • the negative meniscus lens L6 and the positive meniscus lens L7 are cemented.
  • the cemented lens performs focusing and zooming by moving on the optical axis AX.
  • An aperture stop S is arranged between the first lens group G1 and the second lens group G2.
  • the aperture stop S moves together with the second lens group G2.
  • the third lens group G3 includes a plano-convex positive lens L8 having a plane directed to the image side, a biconvex positive lens L9, a biconcave negative lens L10, and a plano-convex positive lens L11 having a plane directed to the image side.
  • the positive lens L9 and the negative lens L10 are cemented to form a cemented lens CL.
  • the plano-convex positive lens L11 is joined to the image sensor IMG via a cover glass CG formed on the image sensor IMG. Further, the plano-convex positive lens L11 may be joined to the image sensor IMG.
  • a is a spherical aberration (SA) in a normal observation state
  • (b) is an astigmatism (AS) in a normal observation state
  • (c) Indicates distortion aberration (DT) in the normal observation state
  • (d) indicates lateral chromatic aberration (CC) in the normal observation state
  • (e) is spherical aberration (SA) in the magnified observation state
  • (f) is astigmatism (AS) in the magnified observation state
  • g) is distortion aberration (DT) in the magnified observation state
  • (h) is magnified.
  • the chromatic aberration of magnification (CC) in the observation state is shown.
  • the objective optical system for an endoscope according to the present embodiment has little fluctuation in the F number from the normal observation state to the magnified observation state. Therefore, an appropriate depth of field is secured without being affected by diffraction in the optical system in each state.
  • FIG. 20A is a lens cross-sectional view of the endoscope objective optical system according to Example 10 in a normal observation state.
  • FIG. 20B is a lens cross-sectional view of the endoscope objective optical system according to Example 10 in a magnified observation state.
  • the objective optical system for an endoscope is composed of only 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 G3 having a positive refractive power in order from the object side. To be done.
  • the first lens group G1 includes, in order from the object side, a plano-concave negative lens L1 having a plane facing the object side, a biconcave negative lens L2, an infrared cut filter F that is a parallel plate, and a biconvex positive lens L3. , A biconvex positive lens L4, and a negative meniscus lens L5 having a convex surface facing the image side.
  • the positive lens L4 and the negative meniscus lens L5 are cemented.
  • the second lens group G2 has a negative meniscus lens L6 having a convex surface directed toward the object side.
  • the negative meniscus lens L6 performs focusing and zooming by moving on the optical axis AX.
  • An aperture stop S is arranged between the first lens group G1 and the second lens group G2.
  • the aperture stop S moves together with the second lens group G2.
  • the third lens group G3 includes a plano-convex positive lens L7 having a flat surface facing the image side, a biconvex positive lens L8, a biconcave negative lens L9, and a plano-convex positive lens L10 having a flat surface facing the image side.
  • the positive lens L8 and the negative lens L9 are cemented to form a cemented lens CL.
  • the plano-convex positive lens L10 is joined to the image sensor IMG via a cover glass CG formed on the image sensor IMG. Further, the plano-convex positive lens L10 may be cemented to the image sensor IMG.
  • spherical aberration SA
  • AS astigmatism
  • DT lateral chromatic aberration
  • CC chromatic aberration
  • the objective optical system for an endoscope according to the present embodiment has little fluctuation in the F number from the normal observation state to the magnified observation state. Therefore, an appropriate depth of field is secured without being affected by diffraction in the optical system in each state.
  • FIG. 22A is a lens cross-sectional view of the objective optical system for an endoscope according to Example 11 in a normal observation state.
  • 22B is a lens cross-sectional view of the endoscope objective optical system according to Example 11 in a magnified observation state.
  • the objective optical system for an endoscope is composed of only 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 G3 having a positive refractive power in order from the object side. To be done.
  • the first lens group G1 includes, in order from the object side, a plano-concave negative lens L1 whose plane is directed toward the object side, a plano-concave negative lens L2 whose plane is directed toward the object side, and an infrared cut filter F which is a parallel plate. , A biconvex positive lens L3 and a biconvex positive lens L4.
  • the second lens group G2 has a negative meniscus lens L5 having a convex surface directed toward the object side.
  • the negative meniscus lens L5 performs focusing and zooming by moving on the optical axis AX.
  • An aperture stop S is arranged between the first lens group G1 and the second lens group G2.
  • the aperture stop S moves together with the second lens group G2.
  • the third lens group G3 includes a plano-convex positive lens L6 having a plane facing the image side, a biconvex positive lens L7, a plano-concave negative lens L8 having a plane facing the image side, and a plano-convex lens having a plane facing the image side. And a convex positive lens L9.
  • the positive lens L7 and the negative lens L8 are cemented to form a cemented lens CL.
  • the plano-convex positive lens L9 is joined to the image sensor IMG via a cover glass CG formed on the image sensor IMG. Further, the plano-convex positive lens L9 may be cemented to the image sensor IMG.
  • a is a spherical aberration (SA) in a normal observation state
  • (b) is an astigmatism (AS) in a normal observation state
  • (c) Indicates distortion aberration (DT) in the normal observation state
  • (d) indicates lateral chromatic aberration (CC) in the normal observation state
  • (e) is spherical aberration (SA) in the magnified observation state
  • (f) is astigmatism (AS) in the magnified observation state
  • g) is distortion aberration (DT) in the magnified observation state
  • (h) is magnified.
  • the chromatic aberration of magnification (CC) in the observation state is shown.
  • the objective optical system for an endoscope according to the present embodiment has little fluctuation in the F number from the normal observation state to the magnified observation state. Therefore, an appropriate depth of field is secured without being affected by diffraction in the optical system in each state.
  • r is the radius of curvature of each lens surface
  • d is the distance between the lens surfaces
  • ne is the e-line refractive index of each lens
  • ⁇ d is the Abbe number of each lens
  • the aperture is the aperture stop.
  • Fno is the F number
  • ⁇ is the half angle of view
  • the unit of the viewing angle (angle of view) is degrees.
  • Numerical Example 1 Unit mm Surface data Surface number r d ne ⁇ d 1 ⁇ 0.4103 1.88815 40.76 2 1.5807 0.9595 1 3 -6.7506 0.3986 1.48915 70.23 4 2.4552 0.3987 1 5 ⁇ 0.3987 1.51825 64.14 6 ⁇ 0.4665 1 7 4.2026 3.0902 1.58482 40.75 8 -4.2026 0.0478 1 9 5.2392 1.2756 1.51977 52.43 10 -2.8684 0.3987 1.93429 18.9 11 -5.6916 Variable 1 12 (aperture) ⁇ 0.0478 1 13 7.2418 0.4007 1.88815 40.76 14 1.7434 0.7076 1.76859 26.52 15 3.4743 Variable 1 16 3.9768 1.307 1.82017 46.62 17 ⁇ 0.0704 1 18 3.74 1.2907 1.64129 55.38 19 -3.74 0.3989 1.93429 18.9 20 8.5597 0.4785 1 21 3.2435 1.7049 1.518
  • Numerical Example 2 Unit mm Surface data Surface number r d ne ⁇ d 1 ⁇ 0.3987 1.88815 40.76 2 1.4156 1.0345 1 3 12.0185 0.5582 1.64769 84.25 4 3.5154 0.4553 1 5 ⁇ 0.4 1.51825 64.14 6 ⁇ 0.05 7 -28.9534 3.0158 1.58482 40.75 8 -2.6236 0.5636 1 9 2.301 1.1001 1.51977 52.43 10 -3.3297 0.3985 1.93429 18.9 11 -33.9265 Variable 1 12 (Aperture) ⁇ 0.0472 1 13 6.3112 0.3985 1.88815 40.76 14 1.1558 0.6467 1.76859 26.52 15 2.4274 Variable 1 16 3.0549 1.2716 1.82017 46.62 17 -52.2548 0.0791 1 18 3.9865 1.4709 1.62033 63.33 19 -2.2768 0.3985 1.93429 18.9 20 34.776 0.4942 1 21 3.
  • Numerical Example 3 Unit mm Surface data Surface number r d ne ⁇ d 1 ⁇ 0.6523 1.88815 40.76 2 1.4402 0.872 1 3 -5.4488 0.4788 1.48915 70.23 4 3.6531 0.6176 1 5 ⁇ 0.4 1.51825 64.14 6 ⁇ 3.2358 1.58482 40.75 7 -2.9521 0.4639 1 8 3.0265 1.2863 1.51977 52.43 9 -3.4743 0.3987 1.93429 18.9 10 -19.6376 Variable 1 11 (Aperture) ⁇ 0.0531 1 12 4.2658 0.3661 1.88815 40.76 13 1.3625 0.6459 1.76859 26.52 14 3.3887 Variable 1 15 4.0036 1.2406 1.82017 46.62 16 ⁇ 0.0755 1 17 4.382 1.2376 1.64129 55.38 18 -3.0232 0.3801 1.93429 18.9 19 5.4857 0.4785 1 20 2.3189 0.9738 1.51825 64.14 21 ⁇
  • Numerical Example 4 Unit mm Surface data Surface number r d ne ⁇ d 1 ⁇ 0.3987 1.88815 40.76 2 1.416 1.0358 1 3 11.0825 0.5582 1.63777 82.75 4 3.5432 0.45 1 5 ⁇ 0.4 1.51825 64.14 6 ⁇ 0.05 1 7 -34.1587 3.0027 1.58482 40.75 8 -2.6513 0.1411 1 9 2.3363 1.1008 1.51977 52.43 10 -3.6809 0.4057 1.93429 18.9 11 -15.4446 Variable 1 12 (Aperture) ⁇ 0.0541 1 13 11.5015 0.395 1.88815 40.76 14 2.2445 0.6557 1.76859 26.52 15 2.201 Variable 1 16 3.0888 1.2656 1.82017 46.62 17 -42.1202 0.0753 1 18 3.8963 1.4343 1.62033 63.33 19 -2.2881 0.3888 1.93429 18.9 20 49.9145 0.4794 1 21 3.4695 0.65
  • Numerical Example 6 Unit mm Surface data Surface number r d ne ⁇ d 1 ⁇ 0.504 1.88815 40.76 2 1.5512 0.9856 1 3 -5.7003 0.4324 1.48915 70.23 4 2.3332 0.3428 1 5 ⁇ 0.3987 1.51825 64.14 6 ⁇ 0.4106 1 7 3.859 3.0624 1.58482 40.75 8 -3.9012 0.0755 1 9 4.9809 1.2741 1.51977 52.43 10 -2.8261 0.2437 1.93429 18.9 11 -6.3344 Variable 1 12 (Aperture) ⁇ 0.2041 1 13 6.7899 0.4542 1.88815 40.76 14 1.7553 0.8036 1.76859 26.52 15 3.5578 Variable 1 16 3.8639 1.3459 1.82017 46.62 17 ⁇ 0.1088 1 18 3.4674 1.1962 1.64129 55.38 19 -3.7036 0.3678 1.93429 18.9 20 11.6443 0.5041 1 21 4.7943 1.3064 1.5
  • Numerical Example 7 Unit mm Surface data Surface number r d ne ⁇ d 1 ⁇ 0.4876 1.88815 40.76 2 1.5559 0.9791 1 3 -5.8755 0.4234 1.48915 70.23 4 2.3526 0.3595 1 5 ⁇ 0.3987 1.51825 64.14 6 ⁇ 0.4273 1 7 3.9584 3.0685 1.58482 40.75 8 -3.9962 0.0478 1 9 4.9984 1.269 1.51977 52.43 10 -2.8943 0.2942 1.93429 18.9 11 -6.2531 Variable 1 12 (Aperture) ⁇ 0.1714 1 13 6.9467 0.4455 1.88815 40.76 14 1.7559 0.7831 1.76859 26.52 15 3.5315 Variable 1 16 3.8826 1.3402 1.82017 46.62 17 ⁇ 0.1023 1 18 3.5359 1.1962 1.64129 55.38 19 -3.7536 0.3927 1.93429 18.9 20 10.7205 0.4976 1 21 4.3505 1.4172 1.5
  • Numerical Example 8 Unit mm Surface data Surface number r d ne ⁇ d 1 ⁇ 0.4448 1.88815 40.76 2 1.7012 0.9113 1 3 -3.9611 0.3987 1.48915 70.23 4 3.2026 0.4048 1 5 ⁇ 0.4 1.51825 64.14 6 ⁇ 3.0093 1.58482 40.75 7 -3.3375 1.5111 1 8 3.9697 1.3121 1.51977 52.43 9 -2.2285 0.6681 1.93429 18.9 10 -4.1055 Variable 1 11 (Aperture) ⁇ 0.0497 1 12 6.3595 0.3987 1.88815 40.76 13 1.6172 0.6459 1.76859 26.52 14 6.0375 Variable 1 15 4.5824 1.26 1.82017 46.62 16 ⁇ 0.0326 1 17 5.7541 1.2376 1.64129 55.38 18 -2.6789 0.3987 1.93429 18.9 19 4.665 0.4785 1 20 2.0465 0.9065 1.51825 64.14 21 ⁇ 0.0087
  • Numerical Example 9 Unit mm Surface data Surface number r d ne ⁇ d 1 ⁇ 0.4627 1.88815 40.76 2 1.6479 0.9108 1 3 -4.2254 0.3828 1.48915 70.23 4 3.3534 0.4402 1 5 ⁇ 0.4 1.51825 64.14 6 ⁇ 3.0268 1.58482 40.75 7 -3.352 1.3954 1 8 4.2557 1.3123 1.51977 52.43 9 -2.3424 0.611 1.93429 18.9 10 -4.3175 Variable 1 11 (Aperture) ⁇ 0.0605 1 12 4.8894 0.3987 1.88815 40.76 13 1.5825 0.6459 1.76859 26.52 14 4.1593 Variable 1 15 4.3271 1.2748 1.82017 46.62 16 ⁇ 0.0478 1 17 5.3424 1.2376 1.64129 55.38 18 -2.9051 0.3987 1.93429 18.9 19 4.7733 0.4767 1 20 2.1128 0.9078 1.51825 64.14 21 ⁇
  • Numerical Example 10 Unit mm Surface data Surface number r d ne ⁇ d 1 ⁇ 0.4348 1.88815 40.76 2 1.6379 1.0228 1 3 -7.8981 0.4946 1.48915 70.23 4 2.3712 0.3129 1 5 ⁇ 0.3987 1.51825 64.14 6 ⁇ 0.1407 1 7 5.0509 3.0915 1.58482 40.75 8 -4.2304 0.0752 1 9 5.7932 1.1231 1.51977 52.43 10 -3.7837 0.2933 1.93429 18.9 11 -5.5006 Variable 1 12 (aperture) ⁇ 0.4539 1 13 8.069 1.0535 1.81264 25.42 14 3.2594 Variable 1 15 3.8175 1.3389 1.82017 46.62 16 ⁇ 0.069 1 17 3.4774 1.3764 1.64129 55.38 18 -3.3931 0.3966 1.93429 18.9 19 10.9074 0.4785 1 20 4.6505 1.0939 1.51825 64.14 21 ⁇ 0.0087 1 22
  • Numerical Example 11 Unit mm Surface data Surface number r d ne ⁇ d 1 ⁇ 0.3987 1.88815 40.76 2 1.6305 0.95 1 3 ⁇ 0.3987 1.48915 70.23 4 2.9248 0.4983 1 5 ⁇ 0.3987 1.51825 64.14 6 ⁇ 1.0499 1 7 7.4213 3.7843 1.58482 40.75 8 -5.4039 0.0478 1 9 6.0038 1.0367 1.76859 26.52 10 -30.5009 Variable 1 11 (Aperture) ⁇ 0.0478 1 12 15.0985 0.3987 1.81264 25.42 13 2.8365 Variable 1 14 4.3998 1.1962 1.82017 46.62 15 ⁇ 0.0478 1 16 6.7551 1.1962 1.64129 55.38 17 -3.6648 1.9139 1.93429 18.9 18 ⁇ 0.9752 1 19 3.2681 2.9159 1.51825 64.14 20 ⁇ 0.0087 1 21 ⁇ 0.5582 1.507 63.26 22 Image plane ⁇ Various data
  • Example 2 Example 3 (1) Fim/F12 -6.36 -6.04 -4.44 (2) FG3v/Fim 13.79 10.12 2.50 (3) FG2/F -6.42 -3.74 -12.19 Conditional expression Example 4
  • Example 5 Example 6 (1) Fim/F12 -5.77 -6.28 -9.97 (2) FG3v/Fim 5.88 14.92 2.21 (3) FG2/F -3.10 -6.84 -7.19 Conditional expression
  • Example 7 Example 8
  • Example 9 (1) Fim/F12 -8.95 -3.79 -3.90 (2) FG3v/Fim 2.98 1.47 1.65 (3) FG2/F -6.93 -19.82 -16.92
  • Example 10 Example 11 (1) Fim/F12 -9.00 -5.19 (2) FG3v/Fim 2.72 7.73 (3) FG2/F -7.47 -4.21
  • the above-mentioned objective optical system for an endoscope may simultaneously satisfy a plurality of configurations. This is preferable for obtaining a good endoscope objective optical system. Also, the combination of preferable configurations is arbitrary. Further, for each conditional expression, only the upper limit value or the lower limit value of the numerical range of the more limited conditional expression may be limited.
  • Magnification observation near point observation
  • small size and sufficient observation depth can be secured
  • wide viewing angle is provided
  • optical aberration is well corrected from the center of the screen to the periphery. Therefore, it is useful for a high-performance objective optical system for an endoscope, which is easy to observe and diagnose a lesion.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
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  • Instruments For Viewing The Inside Of Hollow Bodies (AREA)
  • Endoscopes (AREA)

Abstract

L'invention concerne un système optique d'objectif d'endoscope à haute performance qui permet une observation de grossissement (observation proche du point) en fonction d'un changement de distance par rapport à un objet tout en garantissant une profondeur d'observation suffisante malgré une taille réduite, le système ayant un grand angle de vision, permettant une correction satisfaisante des aberrations optiques du centre de l'écran à la région périphérique, et facilitant l'observation et le diagnostic de lésions.　Le système optique d'objectif d'endoscope est constitué d'un premier groupe de lentilles positives, d'un deuxième groupe de lentilles négatives et d'un troisième groupe de lentilles positives dans l'ordre depuis le côté objet ; le premier groupe de lentilles comprend une première lentille formée à partir d'une seule lentille négative et une seconde lentille formée à partir d'une seule lentille négative, depuis le côté objet ; le deuxième groupe de lentilles se déplace le long de l'axe optique, réglant ainsi la mise au point ou le changement de zoom ; le troisième groupe de lentilles comporte une lentille collée et une seule lentille positive liée à un revêtement en verre formé sur un élément d'imagerie ou l'élément d'imagerie.
PCT/JP2019/007205 2019-02-26 2019-02-26 Système optique d'objectif d'endoscope Ceased WO2020174561A1 (fr)

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