WO2020053922A1 - Système optique d'endoscope, endoscope et système d'endoscope - Google Patents

Système optique d'endoscope, endoscope et système d'endoscope Download PDF

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Publication number
WO2020053922A1
WO2020053922A1 PCT/JP2018/033382 JP2018033382W WO2020053922A1 WO 2020053922 A1 WO2020053922 A1 WO 2020053922A1 JP 2018033382 W JP2018033382 W JP 2018033382W WO 2020053922 A1 WO2020053922 A1 WO 2020053922A1
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WO
WIPO (PCT)
Prior art keywords
optical system
peripheral surface
endoscope
inner peripheral
outer peripheral
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PCT/JP2018/033382
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English (en)
Japanese (ja)
Inventor
研野孝吉
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オリンパス株式会社
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Publication date
Application filed by オリンパス株式会社 filed Critical オリンパス株式会社
Priority to PCT/JP2018/033382 priority Critical patent/WO2020053922A1/fr
Publication of WO2020053922A1 publication Critical patent/WO2020053922A1/fr

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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
    • 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 endoscope optical system, an endoscope, and an endoscope system.
  • an optical device for observing the side for example, there is an endoscope.
  • As the observation with the endoscope for example, there is an observation inside a body cavity and an observation inside a thin pipe. Such observation is performed in a small space. Therefore, the endoscope is required to have a smaller diameter of the insertion portion.
  • opaque substance a granular material or an opaque liquid (hereinafter, referred to as “opaque substance”) exists between the object and the imaging optical system.
  • the powder include sand and colloid.
  • An opaque liquid is, for example, blood.
  • the illumination light hardly reaches the object, so that the object cannot be illuminated with sufficient brightness.
  • the amount of light incident on the imaging optical system from the object is reduced, it becomes difficult to observe the object.
  • Patent Documents 1 to 4 disclose devices in which a transparent cylindrical member (hereinafter, referred to as a “cylindrical member”) is disposed at the tip of the insertion portion.
  • a lens cover is disposed at a distal end of a medical device.
  • a transparent cap is disposed at the distal end of the endoscope.
  • a tip is arranged at the tip of an endoscope.
  • an offset can be provided between the device and the tissue by the lens cover.
  • an opaque liquid can be removed by bringing a transparent cap into contact with an object.
  • an offset can be provided between the device and the tissue by the tip.
  • a lighting unit and an imaging optical system are arranged at the distal end of the medical device and the distal end of the endoscope.
  • the illumination light is reflected on the inner surface of the tubular member.
  • the reflected illumination light enters the imaging optical system, flare occurs due to the incident light. Therefore, it is difficult to clearly observe the image of the object.
  • the inner surface is a part of a spherical surface or a part of an elliptical surface.
  • the illumination light reflected on the inner surface is likely to enter the imaging optical system. Therefore, flare is likely to occur. As a result, it is difficult to perform clear observation.
  • the inner surface is a cylindrical surface.
  • the bottom surface of the cylinder is a plane, and the plane faces the observation optical system.
  • the illumination light reflected on the bottom surface easily enters the imaging optical system. Therefore, flare is likely to occur. As a result, it is difficult to clearly observe the image of the object.
  • the present invention has been made in view of such a problem, and clearly observes an object located in the vicinity of the outer peripheral surface of the distal end optical system and an object in contact with the outer peripheral surface of the distal end optical system. It is an object of the present invention to provide an endoscope optical system, an endoscope, and an endoscope system that can perform the operation.
  • an endoscope optical system includes: A tip member connected to the holding member, An imaging optical system arranged on the holding member, The tip member has a tip optical system, The tip optical system has an inner peripheral surface and an outer peripheral surface, One end of the inner peripheral surface and one end of the outer peripheral surface are located on the optical axis of the imaging optical system, The position of one end of the inner peripheral surface is closer to the imaging optical system than the position of one end of the outer peripheral surface, The space between the inner peripheral surface and the outer peripheral surface is filled with a transparent substance having a refractive index greater than 1.
  • a space filled with gas is formed between the inner peripheral surface and the imaging optical system
  • the imaging optical system is composed of only a transmission surface and has a curvature of field, It is characterized by satisfying the following conditional expression (1). -10 ⁇ P ' ⁇ -0.8
  • P ′ is a Petzval sum and is represented by the following equation: r i is the radius of curvature of the i-th transmission surface, n ′ i is the refractive index on the exit side of the i-th transmission surface, ni is the refractive index on the incident side of the i-th transmission surface; n ′ is the refractive index of the image space, i is the number of the transmission surface, k is the total number of transmission surfaces, It is.
  • An endoscope includes: The endoscope optical system described above; Lighting part, An insertion portion having a holding member, The imaging optical system and the illumination unit are disposed inside the holding member.
  • An endoscope system includes: The endoscope described above, An image processing device; And a light source device.
  • an endoscope optical system capable of clearly observing an object located near the outer peripheral surface of the tip optical system or an object in contact with the outer peripheral surface of the tip optical system, A mirror and an endoscope system can be provided.
  • FIG. 4 is a diagram illustrating an image forming relationship of an optical system having a field curvature aberration. It is a figure showing the 1st example of an illumination part. It is a figure showing the 2nd example of a lighting part. It is a figure showing the 3rd example of a lighting part. It is a figure showing the 4th example of an illumination part. It is a figure showing flare light. It is a figure showing the 1st example of an inner skin. It is a figure showing the 2nd example of an inner skin. It is a graph which shows the relationship of the magnitude
  • FIG. 4 is a diagram illustrating an image forming relationship of an optical system having a field curvature aberration. It is a figure showing the 1st example of an illumination part. It is a figure showing the 2nd example of a lighting part. It is a figure showing the 3rd example of a lighting part. It is a figure showing the 4th example of an illumination part.
  • FIG. 3 is a diagram illustrating a virtual image when an object plane is a plane.
  • FIG. 3 is a diagram illustrating a virtual image when an object surface is a curved surface. It is a figure showing the 1st example of a tip member. It is a figure showing the 2nd example of a tip member. It is a figure showing the 3rd example of a tip member. It is a figure showing the 4th example of a tip member. It is a figure showing the 5th example of a tip member. It is a figure showing the 6th example of a tip member. It is a figure showing a parameter.
  • FIG. 3 is a lens cross-sectional view of the imaging optical system according to the first embodiment.
  • FIG. 3 is a lens cross-sectional view of the imaging optical system according to the first embodiment.
  • FIG. 9 is a lens cross-sectional view of an imaging optical system according to a second embodiment.
  • FIG. 13 is a lens cross-sectional view of an imaging optical system according to a third embodiment.
  • FIG. 3 is an aberration diagram of the image forming optical system according to the first embodiment.
  • FIG. 10 is an aberration diagram of the image forming optical system according to the second embodiment.
  • FIG. 13 is an aberration diagram of the imaging optical system of the third embodiment.
  • FIG. 2 is a cross-sectional view of the endoscope optical system according to the first embodiment.
  • FIG. 9 is a cross-sectional view of the endoscope optical system according to the second embodiment.
  • FIG. 10 is a cross-sectional view of an endoscope optical system according to a third embodiment.
  • FIG. 14 is a sectional view of an endoscope optical system according to a fourth embodiment.
  • FIG. 14 is a sectional view of an endoscope optical system according to a fifth embodiment.
  • FIG. 14 is a sectional view of an endoscope optical system according to a sixth embodiment.
  • FIG. 14 is a sectional view of an endoscope optical system according to a seventh embodiment. It is a figure showing an insertion part of an endoscope of this embodiment. It is a figure showing an example of an endoscope of this embodiment, and an example of an endoscope system.
  • the endoscope optical system includes a distal end member connected to the holding member, and an imaging optical system arranged on the holding member.
  • the optical system has an inner peripheral surface and an outer peripheral surface, one end of the inner peripheral surface and one end of the outer peripheral surface are located on the optical axis of the imaging optical system, and the position of one end of the inner peripheral surface is It is closer to the imaging optical system than the position of one end of the outer peripheral surface, and the space between the inner peripheral surface and the outer peripheral surface is filled with a transparent substance having a refractive index greater than 1 and is connected to the inner peripheral surface to form an image.
  • a space filled with a gas is formed between the optical system and the optical system.
  • the imaging optical system includes only a transmission surface, has a curvature of field, and satisfies the following conditional expression (1). It is characterized by. -10 ⁇ P ' ⁇ -0.8 (1)
  • P ′ is a Petzval sum and is represented by the following equation: r i is the radius of curvature of the i-th transmission surface, n ′ i is the refractive index on the exit side of the i-th transmission surface, ni is the refractive index on the incident side of the i-th transmission surface; n ′ is the refractive index of the image space, i is the number of the transmission surface, k is the total number of transmission surfaces, It is.
  • FIG. 1 is a diagram showing an endoscope optical system according to the present embodiment.
  • the endoscope optical system 1 has a tip member 2 and an imaging optical system 3.
  • the tip member 2 is connected to the holding member 7.
  • the imaging optical system 3 is arranged on the holding member 7. Further, the imaging optical system 3 is composed of only a transmission surface.
  • the tip member 2 and the holding member 7 are illustrated in a separated state for easy viewing.
  • the tip member 2 has a tip optical system 4.
  • the total length can be longer than the cross-sectional length.
  • the total length is the length of the imaging optical system 3 in the optical axis direction.
  • the section length is the length in the direction orthogonal to the optical axis.
  • the shape of the tip optical system 4 can be a shape having an axis of symmetry. By doing so, the tip optical system 4 can be easily manufactured. Further, the imaging performance of the imaging optical system 3 can be improved with a small number of lenses.
  • the shape of the tip optical system 4 has an axis of symmetry, the axis of symmetry is preferably coincident with the optical axis.
  • the tip optical system 4 has an outer peripheral surface 4a and an inner peripheral surface 4b.
  • the position of one end of the outer peripheral surface 4a is farther from the imaging optical system 3 than the position of the other end of the outer peripheral surface 4a.
  • the position of one end of the inner peripheral surface 4b is farther from the imaging optical system 3 than the position of the other end of the inner peripheral surface 4b.
  • the distance between the outer peripheral surface 4a and the optical axis changes from one end to the other end.
  • the range in which the interval changes may be a partial range between one end and the other end, or may be an entire range between one end and the other end.
  • the outer peripheral surface 4a may include a shape in which the distance between the outer peripheral surface 4a and the optical axis gradually increases from one end to the other end (hereinafter, referred to as a “tapered shape”).
  • the distance between the inner peripheral surface 4b and the optical axis changes from one end to the other end.
  • the range in which the interval changes may be a partial range from one end to the other end, or may be an entire range from one end to the other end.
  • the inner peripheral surface 4b may have a tapered shape.
  • the outer peripheral surface 4a has a conical surface and a cylindrical surface.
  • the shape of the outer peripheral surface 4a is not limited to the shape shown in FIG.
  • the inner peripheral surface 4b has a conical surface.
  • the entire surface of the inner peripheral surface 4b may not be a conical surface.
  • the conical surface can be regarded as a surface representing a tapered shape.
  • the tip member 2 is connected to the holding member 7 via the contact surface 4c.
  • the contact surface 4c may be regarded as a part of the inner peripheral surface 4b or a part of the outer peripheral surface 4a. Further, the contact surface 4c may be regarded as a surface different from the inner peripheral surface 4b and the outer peripheral surface 4a.
  • the position of the inner peripheral surface 4b is closer to the optical axis than the position of the outer peripheral surface 4a. Therefore, the inner peripheral surface 4b is located inside the outer peripheral surface 4a.
  • One end of the inner peripheral surface 4b and one end of the outer peripheral surface 4a are located on the optical axis of the imaging optical system 3. The position of one end of the inner peripheral surface 4b is closer to the imaging optical system 3 than the position of one end of the outer peripheral surface 4a.
  • the space between the outer peripheral surface 4a and the inner peripheral surface 4b is filled with a transparent substance having a refractive index larger than 1.
  • the contact surface 4c can be regarded as a surface different from the inner peripheral surface 4b and the outer peripheral surface 4a. In this case, a region surrounded by the inner peripheral surface 4b, the outer peripheral surface 4a, and the contact surface 4c is filled with a transparent substance having a refractive index larger than 1.
  • a space 5 is formed between the inner peripheral surface 4b and the imaging optical system 3.
  • the space 5 is filled with gas.
  • the gas is, for example, air.
  • a parallel flat plate 6 may be arranged between the imaging optical system 3 and the tip member 2. In this case, a space 5 is formed between the inner peripheral surface 4b and the parallel flat plate 6.
  • the outer peripheral surface 4a may be located near the object, or the outer peripheral surface 4a may be brought into close contact with the object. In this manner, the number of opaque substances can be reduced or the opaque substances can be eliminated. As a result, the object can be clearly observed.
  • the tip optical system 4 is moved closer to the object.
  • the tip optical system 4 is further pushed.
  • the shape of the outer peripheral surface 4a is tapered, the distal end optical system 4 can be easily pushed toward the object.
  • the outer peripheral surface 4a can be located near the object, or the outer peripheral surface 4a can be brought into close contact with the object.
  • the object plane is a plane perpendicular to the optical axis.
  • an image sensor can be used.
  • the imaging surface of the imaging device is a flat surface and is located perpendicular to the optical axis. For this reason, in a general optical system, occurrence of field curvature aberration is suppressed.
  • the object plane is located near the outer peripheral surface 4a or on the outer peripheral surface 4a. Since the outer peripheral surface 4a has a tapered shape, the object surface is parallel to the outer peripheral surface 4a. In this case, the object plane does not become a plane perpendicular to the optical axis. Therefore, it is preferable that the imaging optical system 3 has a curvature of field.
  • FIG. 2 is a diagram showing an image forming relationship of an optical system having a field curvature aberration.
  • FIG. 2A shows a case where the object surface is a plane
  • FIG. 2B shows a case where the object surface is a curved surface.
  • the sign of the Petzval sum indicates the direction in which the curvature of field occurs, and the value indicates the amount of occurrence of the curvature of field. Generally, in an optical system having a positive refractive power, the sign of the Petzval sum is negative. In an optical system in which the sign of the Petzval sum is minus, as shown in FIG. 2A, when the object plane OB is a plane, a curved surface with a concave surface facing the object side is formed on the image plane I.
  • the object and the image can be reversed. Therefore, when the object plane OB in FIG. 2A is regarded as an image plane and the image plane I is regarded as an object plane, as shown in FIG. 2B, the object plane OB is a curved surface with a concave surface facing the image side. become. On the other hand, the image plane I becomes a plane. As described above, in an optical system in which the sign of the Petzval sum is minus, a curved object can be formed on a plane. It is preferable that the object surface OB be a curved surface with the concave surface facing the image side, since the focusing range is widened.
  • an optical system in which the sign of the Petzval sum is minus is used for the imaging optical system 3. Since the imaging optical system 3 has a curvature of field, an image of the object surface can be formed on a plane even if the object surface is a curved surface.
  • the imaging optical system 3 In order to form a clear image of the object in a wider range, it is desirable that the imaging optical system 3 generate an appropriate amount of curvature of field. That is, it is desirable to make the value of Petzval sum appropriate.
  • an image of an object is formed via a liquid. Therefore, it is desirable that the value of the Petzval sum in the imaging optical system 3 be determined in consideration of the fact that an image of the object is formed via the liquid.
  • an image of an object is formed with the object surface along the outer peripheral surface 4a. Therefore, it is desirable that the value of the Petzval sum in the imaging optical system 3 be determined in consideration of the fact that an image of an object is formed with the object surface along the outer peripheral surface 4a.
  • the value of the Petzval sum is such that the space from the object to the imaging optical system 3 and the space from the imaging optical system 3 to the image are both filled with air. It is calculated by In calculating the Petzval sum, the distal end optical system 4 is excluded from the endoscope optical system 1. Therefore, the value of Petzval sum is calculated only from the imaging optical system 3.
  • the endoscope optical system 1 satisfies the conditional expression (1). -10 ⁇ P ' ⁇ -0.8 (1)
  • Conditional expression (1) indicates the curvature of the image plane when there is no astigmatism.
  • the curvature on the object plane is too small. In this case, the curvature toward the image side is insufficient around the object facing surface. That is, each point in the peripheral portion is shifted from the optimum object point position. Therefore, a clear image cannot be formed from the center of the visual field to the periphery.
  • the imaging optical system has a curvature of field, and satisfies the conditional expression (1). Therefore, an object located near the outer peripheral surface of the distal end optical system or an object in contact with the outer peripheral surface of the distal end optical system can be clearly observed.
  • the illumination unit is arranged at the insertion section of the endoscope.
  • a light guide or a light emitting diode (LED) is used for the lighting unit.
  • FIG. 3 is a diagram showing a first example of the lighting unit.
  • the insertion section 10 has a holding member 11.
  • the holding member 11 has an illumination unit 12 and a parallel flat plate 6.
  • An imaging optical system (not shown) is arranged inside the holding member 11.
  • the shape of the illumination unit 12 is a ring.
  • the parallel plate 6 is located inside the illumination unit 12.
  • FIG. 4 is a diagram illustrating a second example of the lighting unit.
  • the insertion section 20 has a holding member 11.
  • the holding member 11 includes an illumination unit 21 and the parallel flat plate 6.
  • An imaging optical system (not shown) is arranged inside the holding member 11.
  • the shape of the illumination unit 21 is a crescent shape.
  • FIG. 5 is a diagram showing a third example of the lighting unit.
  • the insertion section 30 has the holding member 11.
  • the holding member 11 has an illumination unit 31 and a parallel flat plate 6.
  • An imaging optical system (not shown) is arranged inside the holding member 11.
  • the shape of the illumination unit 31 is a circle.
  • the parallel plate 6 and the illumination unit 31 are arranged in parallel.
  • FIG. 6 is a diagram showing a fourth example of the illumination unit.
  • the insertion section 40 has the holding member 11.
  • the holding member 11 has an illumination part 41 and a parallel flat plate 6.
  • An imaging optical system (not shown) is arranged inside the holding member 11.
  • the shape of the illumination unit 41 is rectangular.
  • the parallel flat plate 6 and the illumination unit 41 are arranged in parallel.
  • Illumination light emitted from the illumination unit includes diffused light, convergent light, or diffused light and scattered light. By appropriately setting the size and position of the illumination unit, the entire field of view can be illuminated.
  • the endoscope optical system 1 is provided with the distal end member 2.
  • Light incident on the imaging optical system 3 from the object (hereinafter, referred to as “imaging light”) passes through the distal end member 2. Further, the illumination light also passes through the tip member 2.
  • the illumination unit is disposed at a position facing the distal end member 2 and the imaging optical system 3 is disposed at a position facing the space 5.
  • the illumination light passes only through the tip member 2.
  • the imaging light passes through the tip member 2 and the space 5. Therefore, the angle of view of the illumination light differs from the angle of view of the imaging light. As a result, it is difficult to match the illumination range with the field of view.
  • the illumination unit and the imaging optical system 3 are arranged in the same environment. Specifically, it is desirable that the illumination unit and the imaging optical system 3 be arranged at a position facing the space 5.
  • the refractive index between the outer peripheral surface 4a and the inner peripheral surface 4b is larger than 1. Therefore, when the space 5 is filled with air, the refractive index greatly changes at the inner peripheral surface 4b.
  • the refractive index is larger than 1. Therefore, the refractive index does not significantly change on the outer peripheral surface 4a. In this case, the light intensity of the light reflected by the Fresnel reflection decreases. Therefore, generation of flare light does not pose a problem on the outer peripheral surface 4a.
  • FIG. 7 is a diagram showing flare light.
  • FIG. 7A is a diagram illustrating a first example of flare light.
  • FIG. 7B is a diagram illustrating a second example of the flare light.
  • the same components as those in FIG. 3 are denoted by the same reference numerals, and description thereof is omitted.
  • flare light is shown by a solid line.
  • flare light is illustrated by a solid line and a broken line.
  • the insertion section 10 has the holding member 11 and the member 50.
  • the holding member 11 and the member 50 are connected.
  • the holding member 11 includes the imaging optical system 3, the parallel flat plate 6, and the illumination unit 12.
  • the member 50 has a first member 51 and a second member 52.
  • the first member 51 and the second member 52 are integrally formed.
  • the first member 51 has an outer peripheral surface 51a and an inner peripheral surface 51b.
  • the inner peripheral surface 51b is a conical surface having a vertex angle of 90 °.
  • the second member 52 has an outer peripheral surface 52a and an inner peripheral surface 52b. A material that transmits light is used for the first member 51 and the second member 52.
  • the illumination light emitted from the illumination unit 12 enters the inner peripheral surface 52b.
  • the illumination light incident on the inner peripheral surface 52b is reflected by the inner peripheral surface 52b.
  • the illumination light reflected by the inner peripheral surface 52b enters the inner peripheral surface 51b.
  • the illumination light incident on the inner peripheral surface 51b is reflected by the inner peripheral surface 51b.
  • the incident position is a position different from the first reflected position.
  • the illumination light incident on the inner peripheral surface 51b is reflected by the inner peripheral surface 51b.
  • the insertion section 10 has a holding member 11 and a member 60.
  • the holding member 11 and the member 60 are connected.
  • the holding member 11 includes the imaging optical system 3, the parallel flat plate 6, and the illumination unit 12.
  • the member 60 has a first member 61 and a second member 62.
  • the first member 61 and the second member 62 are integrally formed.
  • the first member 61 has an outer peripheral surface 61a and an inner peripheral surface 61b.
  • the inner peripheral surface 61b is a hemispherical surface.
  • the second member 62 has an outer peripheral surface 62a and an inner peripheral surface 62b.
  • a material that transmits light is used for the first member 61 and the second member 62.
  • the illumination light emitted from the illumination unit 12 enters the inner peripheral surface 61b.
  • the illumination light that has entered the inner peripheral surface 61b is reflected by the inner peripheral surface 61b.
  • ⁇ ⁇ ⁇ Also, of the illumination light reflected on the inner peripheral surface 61b, a part of the illumination light is incident on the inner peripheral surface 61b again.
  • the incident position is a position different from the first reflected position.
  • the illumination light that has entered the inner peripheral surface 61b is reflected by the inner peripheral surface 61b.
  • the generation of flare light has been described above using the member 50 and the member 60.
  • the distal end member is connected to the holding member.
  • the tip member is made of a material that transmits light, like the members 50 and 60.
  • the space between the tip member and the holding member can be filled with air. Therefore, it is important to suppress generation of flare light also in the optical system of the present embodiment.
  • the inner peripheral surface is a surface including the side surface of the truncated cone, and the truncated cone may be a part of a cone satisfying the following conditional expression (2). preferable. 0 ° ⁇ ⁇ 70 ° (2) Where ⁇ is the cone apex angle, It is.
  • the inner peripheral surface is a surface including the side surface of the truncated cone.
  • FIG. 8 is a diagram illustrating a first example of the inner peripheral surface.
  • FIG. 9 is a diagram illustrating a second example of the inner peripheral surface.
  • the endoscope optical system 70 includes the distal end member 71 and the imaging optical system 3.
  • the tip member 71 has a tip optical system 72.
  • the tip optical system 72 has an outer peripheral surface 72a and an inner peripheral surface 72b.
  • the outer peripheral surface 72a has a conical surface and a cylindrical surface.
  • the inner peripheral surface 72b has a first inner peripheral surface 72b1 and a second inner peripheral surface 72b2.
  • the first inner peripheral surface 72b1 is a side surface of a truncated cone.
  • the second inner peripheral surface 72b2 is a hemispherical surface.
  • the inner peripheral surface 72b is a surface including the side surface of the truncated cone.
  • the second inner peripheral surface 72b2 is drawn large for easy viewing.
  • the ratio of the second inner peripheral surface 72b2 to the inner peripheral surface 72b is preferably as small as possible.
  • the endoscope optical system 80 includes the distal end member 81 and the imaging optical system 3.
  • the tip member 81 has a tip optical system 82.
  • the tip optical system 82 has an outer peripheral surface 82a and an inner peripheral surface 82b.
  • the outer peripheral surface 82a has a hemispherical surface and a cylindrical surface.
  • the inner peripheral surface 82b has a conical surface. A portion of the conical surface can be considered as the side of the truncated cone. Thus, the inner peripheral surface 82b is a surface including the side surface of the truncated cone.
  • the inner peripheral surface is a semi-elliptical surface or a hemispherical surface
  • the illumination light having one reflection is likely to enter the imaging optical system.
  • the number of reflections is small, particularly strong flare occurs.
  • the inner peripheral surface 72b and the inner peripheral surface 82b are surfaces including the side surfaces of the truncated cone. Therefore, it is possible to suppress the occurrence of flare due to the illumination light having one reflection.
  • the cone 73 is a cone that satisfies the conditional expression (2). Therefore, in the endoscope optical system 70, the truncated cone is a part of the cone satisfying the conditional expression (2).
  • the cone forming the inner peripheral surface 82b is a cone that satisfies the conditional expression (2). Therefore, in the endoscope optical system 80, the truncated cone is a part of the cone satisfying the conditional expression (2).
  • the truncated cone is a part of the cone satisfying the conditional expression (2). Therefore, the occurrence of flare can be further suppressed.
  • the value exceeds the upper limit value of the conditional expression (2) the number of reflections of the illumination light on the inner peripheral surface is likely to be two. In this case, since the illumination light easily enters the imaging optical system, flare easily occurs.
  • FIG. 10 is a graph showing the relationship between the magnitude of flare light and the apex angle of a cone.
  • the vertical axis is the peak irradiance of flare light (Watts / cm 2 ).
  • the horizontal axis is the angle of the apex of the cone.
  • the unit of irradiance is Watts / cm 2 , and the unit of apex angle is degree.
  • the magnitude of flare light is determined by simulation.
  • both the outer peripheral surface and the inner peripheral surface are assumed to be conical surfaces, and further, it is assumed that the apex angle of the conical surface of the outer peripheral surface is equal to the apex angle of the conical surface of the inner peripheral surface.
  • the magnitude of flare light is calculated based on ray tracing. Of the illumination light reflected on the inner peripheral surface, the magnitude of flare light is calculated based on light rays that pass through the imaging optical system and reach the image plane.
  • the flare light depends on the shape of the illumination unit and the relative position between the illumination unit and the imaging optical system.
  • the simulation was performed for concentric arrangement and parallel arrangement. In the concentric arrangement, as shown in FIG. 3, the imaging optical system and the illumination section are arranged concentrically. In the parallel arrangement, as shown in FIG. 5, the imaging optical system and the illumination unit are arranged in parallel.
  • the solid line and the broken line show the simulation results in the concentric arrangement.
  • the one-dot chain line and the two-dot chain line indicate simulation results in the parallel arrangement.
  • the solid line and the dashed line indicate the simulation results assuming that flare light is generated on the inner peripheral surface and the outer peripheral surface.
  • the broken line and the two-dot chain line show the simulation results assuming that flare light is generated only on the inner peripheral surface.
  • conditional expression (2) 0 ° ⁇ ⁇ 50 ° (2 ')
  • conditional expression (2 ') By satisfying conditional expression (2 '), the peak irradiance of flare light can be further reduced. Therefore, the occurrence of flare can be further suppressed.
  • the total length of the tip optical system becomes long.
  • the hard length increases.
  • the endoscope optical system of the present embodiment is used for a rigid endoscope or the like, it is important to satisfy the conditional expression (2 ').
  • the hard length is the total length of the tip member.
  • the hard length is the entire length of the distal end optical system.
  • the distal end member can have a distal end optical system and a holding frame.
  • the hard length can be regarded as a length obtained by adding the entire length of the holding frame to the entire length of the tip optical system.
  • the tip member can be connected to the holding member.
  • the hard length can be regarded as the total length of the tip member plus the entire length of the hard part.
  • conditional expression (2 ') the instrument can be stably operated in applications such as surgery and puncture. Further, the instrument can be stably moved with respect to the object even in a relatively hard part.
  • the lower limit can be set to 0 ° or 20 °. Further, the upper limit can be set to 40 °.
  • the apex angle of the cone can be less than 20 °. By doing so, the occurrence of flare can be further suppressed.
  • the inner peripheral surface is a surface including the side surface of the truncated cone, and the truncated cone is a part of a cone satisfying the following conditional expression (2 ′′). Is preferred. 130 ° ⁇ ⁇ 170 ° (2 ”) Where ⁇ is the cone apex angle, It is.
  • Conditional expression (2 ′′) is a conditional expression for suppressing the occurrence of flare. By satisfying conditional expression (2 ′′), the occurrence of flare can be suppressed.
  • the endoscope optical system according to the present embodiment is used for a flexible endoscope, it is important to satisfy the conditional expression (2 ′′).
  • Flexible endoscopes are used, for example, for bronchial observation, blood vessel observation, and urological observation.
  • the flexible endoscope is also used for observation and inspection in otolaryngology. In these observations, the objects are often thin, meandering lumens.
  • the peak irradiance of the flare light is particularly large when the apex angle of the cone is around 120 °. Therefore, when the apex angle of the cone is around 120 °, flare is likely to occur.
  • the occurrence of flare can be suppressed by making the shape of the outer peripheral surface and the shape of the inner peripheral surface tapered.
  • the imaging light is obliquely incident on the outer peripheral surface and the inner peripheral surface. Therefore, aberration occurs.
  • the inner peripheral surface and the outer peripheral surface can be surfaces having a symmetry axis. With this configuration, the inner peripheral surface and the outer peripheral surface are rotationally symmetric with respect to the optical axis.
  • An example of a rotationally symmetric surface with respect to the optical axis is a spherical surface. Aberrations occurring on a spherical surface are less complicated than aberrations occurring on a non-rotationally symmetric surface.
  • the inner peripheral surface and the outer peripheral surface are not spherical.
  • the outer peripheral surface and the inner peripheral surface include a tapered shape. For this reason, more complicated eccentric aberration occurs as compared with a spherical surface.
  • a tapered shape for example, a shape including a side surface of a truncated cone
  • the cross-sectional shape in a plane orthogonal to the optical axis is a circle.
  • the radius of curvature of the circle changes in the optical axis direction.
  • the radius of curvature at one end is much smaller than the radius of curvature at the other end. Therefore, very large astigmatism occurs on the inner peripheral surface. This will be described.
  • FIG. 11 is a diagram showing a virtual image when the object plane is a plane.
  • FIG. 12 is a diagram illustrating a virtual image when the object surface is a curved surface.
  • the outer peripheral surface 4a and the inner peripheral surface 4b are side surfaces of a truncated cone.
  • the object plane OB is separated from the entrance pupil of the imaging optical system 3 by 0.7 mm.
  • Light beam Lam, light beam Lbm, light beam Lcm, light beam Lam ', light beam Lbm', and light beam Lcm ' are light beams in a meridional section.
  • the light beam Lbs and the light beam Lbs' are light beams in a sagittal section.
  • the light beam Lam, the light beam Lbm, the light beam Lcm, and the light beam Lbs are light beams that indicate the object plane OB.
  • the light beam Lam ', the light beam Lbm', and the light beam Lcm ' are light beams showing a virtual image Imeri in the meridional section.
  • the light beam Lbs' is a light beam showing a virtual image Isagi in a sagittal section.
  • the luminous flux Lam is a luminous flux when the angle of view is 9 °.
  • the light beam Lbm and the light beam Lbs are light beams when the angle of view is 19 °.
  • the light flux Lcm is a light flux when the angle of view is 29 °.
  • the radius of curvature in the meridional section and the radius of curvature in the sagittal section are different between the outer peripheral surface 4a and the inner peripheral surface 4b.
  • the convergence position PLbm 'of the light beam Lbm' is different from the convergence position of the light beam Lbs'. That is, astigmatism ⁇ AS occurs. Therefore, the position of the virtual image Imeri is different from the position of the virtual image Isagi.
  • the object surface OB can be regarded as a curved surface.
  • the object surface OB is a spherical surface having a radius of 0.4 mm with the concave surface facing the entrance pupil side.
  • the object surface OB is a curved surface
  • the object surface OB is curved along the outer peripheral surface 4a.
  • each point on the object plane OB is located substantially along the outer peripheral surface 4a.
  • the virtual image also has a curved surface with the concave surface facing the entrance pupil side of the imaging optical system 3.
  • the radius of curvature in the meridional section and the radius of curvature in the sagittal section are different between the outer peripheral surface 4a and the inner peripheral surface 4b.
  • the convergence position PLbm 'of the light beam Lbm' is different from the convergence position of the light beam Lbs'. That is, astigmatism ⁇ AS occurs. Therefore, the position of the virtual image Imeri is different from the position of the virtual image Isagi.
  • the imaging optical system 3 has the curvature of field, as shown in FIG. 12, the amount of astigmatism ⁇ AS is smaller than that in FIG.
  • the shape of the virtual image can be made suitable for imaging.
  • the shape suitable for imaging is a shape in which a clear image can be captured by a planar imaging device.
  • the virtual image has a shape along the outer peripheral surface 4a, astigmatism generated by the inner peripheral surface 4b can be reduced. This is because the luminous flux transmitted through the inner peripheral surface 4b becomes thinner as the position of the virtual image approaches the outer peripheral surface 4a.
  • the imaging optical system preferably has a curvature of field.
  • astigmatism can be reduced. As a result, a clear object image can be easily formed.
  • the imaging optical system is preferably a ball lens.
  • the ball lens can be used as it is. Therefore, a small-diameter imaging optical system can be realized at low cost.
  • the imaging optical system is preferably a plano-convex lens.
  • the diameter of the imaging optical system is very small.
  • the diameter is 1 mm or less, it becomes difficult to manufacture a lens, and thus the cost increases. Also, assembly becomes difficult.
  • a plano-convex lens can be obtained, for example, by shaving one side of a ball lens into a plane. As described above, since the plano-convex lens is easy to manufacture, a small-diameter imaging optical system can be realized at low cost.
  • the imaging optical system preferably includes at least two plano-convex lenses.
  • the imaging optical system includes two plano-convex lenses, the focal length of the imaging optical system can be shortened, and the occurrence of astigmatism can be suppressed. Therefore, an imaging optical system having a wide angle of view can be realized while reducing the diameter of the insertion portion.
  • the imaging optical system is a gradient index lens.
  • both end faces can be flat. Therefore, the assembly of the optical system becomes easy.
  • the imaging optical system includes a first positive lens and a second positive lens in order from the tip member side, and the first predetermined surface is The first positive lens is a lens surface on the image side, the second predetermined surface is a lens surface on the tip member side of the second positive lens, and the first predetermined surface is directed toward the second lens. It is preferable that the second predetermined surface is convex toward the first lens.
  • a ball lens is a lens that can be manufactured with low difficulty and high accuracy.
  • astigmatism is largely generated on the minus side.
  • astigmatism occurs in a minus direction. Therefore, when a ball lens is used in the imaging optical system, astigmatism is further increased.
  • astigmatism can be generated on the plus side. That is, the amount of astigmatism occurring on the minus side can be made smaller than that of the ball lens. As a result, the amount of astigmatism can be reduced as a whole.
  • the convex surface having a positive refractive power can be realized by a plano-convex lens.
  • a plano-convex lens can be obtained by shaving one side of a ball lens into a plane.
  • the ball lens has low difficulty in manufacturing and can be manufactured with high accuracy. Therefore, a plano-convex lens can also be easily manufactured with high accuracy.
  • the endoscope optical system of the present embodiment satisfies the following conditional expression (3). 0.2 ⁇
  • the endoscope optical system of the present embodiment can be used for an optical system of an industrial endoscope.
  • Industrial endoscopes require particularly high convenience. In order to realize high convenience, for example, an object having different hole sizes may be observed with one endoscope.
  • the range of the diameter of the hole to be observed is, for example, from 1.5 mm to 8 mm.
  • the diameter of the tip may be 1 mm.
  • the endoscope optical system may be an optical system suitable for observing a hole having a diameter of 4 mm. By doing so, one endoscope can observe a range from 1.5 mm to 8 mm.
  • the object point position is 2 mm.
  • the object point position is longer than 2 mm. That is, the object point position moves away from the endoscope optical system.
  • the imaging optical system be an optical system that generates astigmatism on the plus side.
  • the optical system in which astigmatism occurs on the plus side can be realized by arranging convex surfaces having positive refractive power to face each other. Further, by satisfying conditional expression (3), astigmatism can be generated on the plus side.
  • conditional expression (3) If the value is below the lower limit value of conditional expression (3), astigmatism generated by the imaging optical system cannot be sufficiently generated on the plus side. When the value exceeds the upper limit value of the conditional expression (3), astigmatism generated by the imaging optical system is excessively generated on the plus side. In either case, the range that can be clearly observed cannot be widened.
  • the distal end member preferably has a holding frame, and the holding frame is preferably located at the other end of the outer peripheral surface.
  • FIG. 13 is a diagram showing a first example of the tip member.
  • the tip member 90 has a tip optical system 91 and a holding frame 92.
  • the tip optical system 91 and the holding frame 92 are integrally formed.
  • the tip optical system 91 has an outer peripheral surface 91a and an inner peripheral surface 91b.
  • the outer peripheral surface 91a has a first outer peripheral surface 91a1 and a second outer peripheral surface 91a2.
  • the first outer peripheral surface 91a1 is a hemispherical surface.
  • the second outer peripheral surface 91a2 is a cylindrical surface.
  • the inner peripheral surface 91b has a first inner peripheral surface 91b1 and a second inner peripheral surface 91b2.
  • the first inner peripheral surface 91b1 is a side surface of a truncated cone.
  • the second inner peripheral surface 91b2 is a hemispherical surface.
  • the holding frame 92 has an outer peripheral surface 92a and an inner peripheral surface 92b.
  • the outer peripheral surface 92a and the inner peripheral surface 92b are cylindrical surfaces.
  • FIG. 14 is a diagram showing a second example of the distal end member.
  • the distal member 100 has a distal optical system 101 and a holding frame 92.
  • the tip optical system 101 and the holding frame 92 are integrally formed. Since the inner peripheral surface 91b and the holding frame 92 are the same as those in the first example, the description is omitted.
  • the tip optical system 101 has an outer peripheral surface 101a and an inner peripheral surface 91b.
  • the outer peripheral surface 101a has a first outer peripheral surface 101a1 and a second outer peripheral surface 101a2.
  • the first outer peripheral surface 101a1 is a hemispherical surface.
  • the second outer peripheral surface 101a2 is a side surface of a truncated cone.
  • the second outer peripheral surface 101a2 is parallel to the first inner peripheral surface 91b1.
  • FIG. 15 is a view showing a third example of the tip member.
  • the tip member 110 has a tip optical system 111 and a holding frame 112.
  • the tip optical system 111 and the holding frame 112 are integrally formed. Since the inner peripheral surface 91b is the same as in the first example, the description is omitted.
  • the tip optical system 111 has an outer peripheral surface 111a and an inner peripheral surface 91b.
  • the outer peripheral surface 111a has a first outer peripheral surface 111a1 and a second outer peripheral surface 111a2.
  • the first outer peripheral surface 111a1 is a hemispherical surface.
  • the second outer peripheral surface 111a2 is a side surface of a truncated cone.
  • the second outer peripheral surface 111a2 is non-parallel to the first inner peripheral surface 91b1.
  • the holding frame 112 has an outer peripheral surface 112a and an inner peripheral surface 112b.
  • the outer peripheral surface 112a and the inner peripheral surface 112b are side surfaces of a truncated cone.
  • the shape of the holding frame 112 is a tapered shape.
  • FIG. 16 is a view showing a fourth example of the tip member.
  • the tip member 120 has a tip optical system 121 and a holding frame 122.
  • the tip optical system 121 and the holding frame 122 are integrally formed. Since the inner peripheral surface 91b is the same as in the first example, the description is omitted.
  • the tip optical system 121 has an outer peripheral surface 121a and an inner peripheral surface 91b.
  • the outer peripheral surface 121a is an elliptical surface.
  • the holding frame 122 has an outer peripheral surface 122a and an inner peripheral surface 122b.
  • the outer peripheral surface 122a is an elliptical surface.
  • the inner peripheral surface 122b is a cylindrical surface.
  • the shape of the holding frame 122 is a tapered shape.
  • FIG. 17 is a diagram showing a fifth example of the tip member.
  • the tip member 130 has a tip optical system 91 and a holding frame 131.
  • the tip optical system 91 and the holding frame 131 are integrally formed. Since the tip optical system 91 is the same as that of the first example, the description is omitted.
  • the holding frame 131 has an outer peripheral surface 131a and an inner peripheral surface 131b.
  • the outer peripheral surface 131a is a cylindrical surface.
  • the shape of the inner peripheral surface 131b is a shape in which a screw is formed on a cylindrical surface.
  • FIG. 18 is a diagram showing a sixth example of the distal end member.
  • the tip member 140 has a tip optical system 91 and a holding frame 141.
  • the tip optical system 91 and the holding frame 141 are integrally formed. Since the tip optical system 91 is the same as that of the first example, the description is omitted.
  • the holding frame 141 has an outer peripheral surface 141a, an inner peripheral surface 141b, and a side surface 141c.
  • the outer peripheral surface 141a and the inner peripheral surface 141b are cylindrical surfaces.
  • the side surface 141c is a flat surface, and a metal film is formed on the surface.
  • the tip member 140 can be connected to the holding member by soldering or metal brazing.
  • the endoscope optical system of the present embodiment satisfies the following conditional expression (4). 0 ⁇ L / D ⁇ 2 (4) here, L is a distance from one end of the outer peripheral surface to a predetermined intersection, D is the outer diameter of the tip optical system, The predetermined intersection is an intersection between a predetermined line and the optical axis, The predetermined line is a straight line that is in contact with the other end of the outer peripheral surface and is orthogonal to the optical axis; It is.
  • Conditional expression (4) is a conditional expression relating to the hard length.
  • the endoscope optical system according to the present embodiment is used for a flexible endoscope, it is preferable to satisfy the conditional expression (4).
  • FIG. 19 is a diagram showing parameters used in the conditional expression (4).
  • the tip member 150 and the holding member 7 are illustrated in a separated state for easy viewing.
  • the tip member 150 has a tip optical system 151 and a holding frame 152.
  • the tip optical system 151 has an outer peripheral surface 151a and an inner peripheral surface 151b.
  • the outer peripheral surface 151a has a conical surface and a cylindrical surface.
  • the inner peripheral surface 151b has a first inner peripheral surface 151b1 and a second inner peripheral surface 151b2.
  • the first inner peripheral surface 151b1 is a side surface of the truncated cone.
  • the truncated cone is part of the cone 153.
  • the second inner peripheral surface 151b2 is a hemispherical surface.
  • the L is a distance from one end E1 of the outer peripheral surface 151a to a predetermined intersection P.
  • the predetermined intersection P is an intersection between the predetermined line LP and the optical axis AX.
  • the predetermined line LP is a straight line that is in contact with the other end E2 of the outer peripheral surface 151a and that is orthogonal to the optical axis AX.
  • the tip optical system 151 and the holding frame 152 are integrally formed. Therefore, in FIG. 19, the other end E2 of the outer peripheral surface 151a is indicated by a broken line.
  • the D is the outer diameter of the tip optical system 150.
  • the outer diameter of the tip optical system 150 can be regarded as the cross-sectional length of the outer peripheral surface 151a.
  • the cross-sectional length of the outer peripheral surface 151a may vary depending on the position in the optical axis direction. In this case, the maximum cross-sectional length among the cross-sectional lengths of the outer peripheral surface 151a may be set to the outer diameter of the tip optical system 150.
  • the flexible endoscope is used, for example, for bronchial observation, blood vessel observation, and urology observation.
  • the flexible endoscope is also used for observation and inspection in otolaryngology. In these observations, the objects are often thin, meandering lumens.
  • the overall length of the tip optical system is reduced.
  • the hard length of the flexible endoscope can be shortened. If the hard length can be shortened, a large bending angle can be obtained with a small turning radius. Therefore, when inserting the flexible endoscope into the lumen, the distal end of the endoscope can easily reach the end of the object.
  • the overall length of the tip optical system becomes longer.
  • the rigid length of the flexible endoscope becomes longer. Therefore, the distal end of the endoscope cannot reach the end of the bronchus or the end of the blood vessel.
  • the endoscope optical system of the present embodiment satisfies the following conditional expression (4 ′). 2 ⁇ L / D ⁇ 10 (4 ′) here, L is a distance from one end of the outer peripheral surface to a predetermined intersection, D is the outer diameter of the tip optical system, The predetermined intersection is an intersection between a predetermined line and the optical axis, The predetermined line is a straight line that is in contact with the other end of the outer peripheral surface and is orthogonal to the optical axis; It is.
  • Conditional expression (4 ') is a conditional expression relating to the hard length.
  • the endoscope optical system according to the present embodiment is used for a rigid endoscope, it is preferable to satisfy the conditional expression (4 ').
  • conditional expression (4 ') is satisfied, the total length of the tip optical system becomes longer. As the total length of the tip optical system increases, the hard length increases. In particular, in the case of a rigid endoscope, an instrument used for a surgical operation, or an instrument used for puncturing, the endoscope or the instrument is moved linearly. If the hard length is long, linear movement can be performed stably.
  • the inner peripheral surface includes a side surface of a truncated cone and a curved surface, and the curved surface has a part of a spherical surface and is located at one end of the inner peripheral surface. It is preferable to satisfy the conditional expression (5). 0mm ⁇ R0 ⁇ 0.5mm (5) here, R0 is the radius of curvature of the spherical surface, It is.
  • conditional expression (5) generation of flare light on a curved surface can be suppressed. If the value exceeds the upper limit of conditional expression (5), the occurrence of flare light on a curved surface increases.
  • the endoscope optical system of the present embodiment satisfies the following conditional expression (6).
  • 0.1mm ⁇ f ⁇ 0.8mm (6) here, f is the focal length of the imaging optical system, It is.
  • the focal length of the imaging optical system is very short. For example, if the outer diameter of the distal end of the endoscope is 2 mm, the outer diameter of the distal optical system is about 2.5 mm.
  • the object point position is near the outer peripheral surface of the tip optical system. In order to focus on the vicinity of the outer peripheral surface, it is important to satisfy conditional expression (6).
  • the endoscope optical system of the present embodiment satisfies the following conditional expression (7).
  • OB is the paraxial object point distance D is the maximum outer diameter of the tip optical system
  • the paraxial object point distance is the object point distance in the paraxial region, and the distance from the lens surface closest to the object side of the imaging optical system to the object point, It is.
  • conditional expression (7) If the value is below the lower limit value of the conditional expression (7), the in-focus object point position is located closer to the inner circumferential surface than the outer circumferential surface. Therefore, a clear optical image cannot be formed. If the value exceeds the upper limit of conditional expression (7), astigmatism generated on the inner peripheral surface of the tip optical system will be too large. Therefore, the resolution in the sagittal direction is deteriorated. As a result, a clear optical image cannot be formed.
  • FIG. 20 shows a lens cross-sectional view of the imaging optical system of the first embodiment.
  • the imaging optical system according to the first embodiment includes a biconvex lens L1.
  • the aperture stop S is arranged on the object side surface of the biconvex lens L1. It is preferable that the biconvex lens L1 is a ball lens.
  • FIG. 21 shows a lens cross-sectional view of the imaging optical system of the second embodiment.
  • the imaging optical system according to the second embodiment includes a plano-convex lens L1 and a convex-plano lens L2.
  • the plano-convex lens L1 is located on the image side
  • the convex-plano lens L2 is located on the object side.
  • the aperture stop S is arranged on the object side surface of the convex flat lens L2.
  • FIG. 22 shows a lens cross-sectional view of the imaging optical system of the third embodiment.
  • the imaging optical system according to the third embodiment includes a plano-convex lens L1 and a plano-convex lens L2.
  • the plano-convex lens L1 is located on the image side, and the convex-plano lens L2 is located on the object side.
  • the aperture stop S is arranged on the object side surface of the convex flat lens L2.
  • Numerical data of each of the above embodiments is shown below.
  • r is the radius of curvature of each lens surface
  • d is the distance between each lens surface
  • nd is the refractive index of the d-line of each lens
  • vd is the Abbe number of each lens.
  • the stop is an aperture stop.
  • Numerical data is data at the time of reverse tracking. In reverse tracing, light rays are traced from the image plane to the object plane.
  • f is the focal length of the entire system
  • ⁇ is a half angle of view
  • IH is the image height
  • ⁇ ap is the diameter of the stop.
  • the image height IH represents the outer diameter of the annular image.
  • Example 1 Example 2
  • Example 3 (1) P '-3.375 -2.642 -4.096 (3)
  • FIGS. Aberration diagrams of each example are shown in FIGS. The aberration diagrams of each embodiment will be described.
  • SA spherical aberration
  • AS astigmatism
  • DT distortion
  • FIG. 26 is a sectional view of the endoscope optical system according to the first embodiment.
  • the endoscope optical system 160 according to the first embodiment includes a tip member 161 and an imaging optical system 164.
  • the imaging optical system according to the first embodiment is used as the imaging optical system 164.
  • the tip member 161 has a tip optical system 162 and a holding frame 163.
  • the tip optical system 162 has an outer peripheral surface 162a and an inner peripheral surface 162b.
  • the outer peripheral surface 162a has a conical surface and a cylindrical surface.
  • the inner peripheral surface 162b is a conical surface.
  • the conical surface on the outer peripheral surface 162a and the conical surface on the inner peripheral surface 162b are parallel.
  • FIG. 27 is a sectional view of the endoscope optical system according to the second embodiment.
  • the endoscope optical system 170 according to the second embodiment includes a tip member 171 and an imaging optical system 174.
  • the imaging optical system according to the first embodiment is used as the imaging optical system 174.
  • the tip member 171 has a tip optical system 172 and a holding frame 173.
  • the tip optical system 172 has an outer peripheral surface 172a and an inner peripheral surface 172b.
  • the outer peripheral surface 172a has a hemispherical surface, a conical surface, and a cylindrical surface.
  • the inner peripheral surface 172b is a conical surface.
  • the conical surface on the outer peripheral surface 172a and the conical surface on the inner peripheral surface 172b are parallel.
  • FIG. 28 is a sectional view of the endoscope optical system according to the third embodiment.
  • the endoscope optical system 180 according to the third embodiment includes a distal end member 181 and an imaging optical system 184.
  • the imaging optical system according to the first embodiment is used for the imaging optical system 184.
  • the tip member 181 has a tip optical system 182 and a holding frame 183.
  • the tip optical system 182 has an outer peripheral surface 182a and an inner peripheral surface 182b.
  • the outer peripheral surface 182a has a hemispherical surface, a conical surface, and a cylindrical surface.
  • the inner peripheral surface 182b is a conical surface.
  • the conical surface on the outer peripheral surface 182a and the conical surface on the inner peripheral surface 182b are parallel.
  • FIG. 29 is a sectional view of the endoscope optical system according to the fourth embodiment.
  • the endoscope optical system 190 according to the fourth embodiment includes a distal end member 191 and an imaging optical system 194.
  • the imaging optical system according to the first embodiment is used as the imaging optical system 194.
  • the tip member 191 has a tip optical system 192 and a holding frame 193.
  • the tip optical system 192 has an outer peripheral surface 192a and an inner peripheral surface 192b.
  • the outer peripheral surface 192a has a curved surface and a cylindrical surface.
  • the curved surface is a part of the ellipsoid.
  • the inner peripheral surface 192b is a conical surface.
  • FIG. 30 shows a sectional view of the endoscope optical system of the fifth embodiment.
  • the endoscope optical system 200 according to the fifth embodiment includes a distal end member 201 and an imaging optical system 204.
  • the imaging optical system according to the first embodiment is used as the imaging optical system 204.
  • the tip member 201 has a tip optical system 202 and a holding frame 203.
  • the tip optical system 202 has an outer peripheral surface 202a and an inner peripheral surface 202b.
  • the outer peripheral surface 202a has a curved surface and a cylindrical surface.
  • the curved surface is a part of the ellipsoid.
  • the inner peripheral surface 202b is a conical surface.
  • FIG. 31 shows a sectional view of the endoscope optical system of the sixth embodiment.
  • the endoscope optical system 210 according to the sixth embodiment includes a distal end member 211 and an imaging optical system 214.
  • the imaging optical system according to the second embodiment is used as the imaging optical system 214.
  • the tip member 211 has a tip optical system 212 and a holding frame 213.
  • the tip optical system 212 has an outer peripheral surface 212a and an inner peripheral surface 212b.
  • the outer peripheral surface 212a has a conical surface and a cylindrical surface.
  • the inner peripheral surface 212b is a conical surface.
  • the conical surface on the outer peripheral surface 212a and the conical surface on the inner peripheral surface 212b are parallel.
  • FIG. 32 shows a sectional view of the endoscope optical system of the seventh embodiment.
  • the endoscope optical system 220 according to the seventh embodiment includes a distal end member 221 and an imaging optical system 224.
  • the imaging optical system according to the third embodiment is used as the imaging optical system 224.
  • the tip member 221 has a tip optical system 222 and a holding frame 223.
  • the tip optical system 222 has an outer peripheral surface 222a and an inner peripheral surface 222b.
  • the outer peripheral surface 222a has a conical surface and a cylindrical surface.
  • the inner peripheral surface 222b is a conical surface.
  • the conical surface on the outer peripheral surface 222a and the conical surface on the inner peripheral surface 222b are parallel.
  • Example 1 Example 2
  • Example 3 (2) ⁇ 60 20 10 (2 ”) ⁇ --- (4) L / D 1.03-- (4 ') L / D-2.76 4.91 (5) R0 0 0 0 (7) OB / D 1.416 1.416 1.416
  • Example 4 Example 5 (2) ⁇ 60 20 (2 ”) ⁇ -- (4) L / D 1.03- (4 ') L / D-2.76 (5) R0 0 0 (7) OB / D 1.416 1.416
  • Example 6 Example 7 (2) ⁇ 60 60 (2 ”) ⁇ -- (4) L / D 1.03 1.03 (4 ') L / D-- (5) R0 0 0 (7) OB / D 0.951 0.719
  • d is the inner diameter of the tip optical system
  • ndt is the refractive index of the tip optical system.
  • Example 1 Example 2
  • Example 3 L 1.55 4.15 7.36 D 1.5 1.5 1.5 OB 2.124 2.124 2.124 d 1.0 1.0 1.0 ndt 1.51633 1.51633 1.51633
  • Example 4 Example 5
  • Example 5 L 1.55 4.15 D 1.5 1.5 OB 2.124 2.124 d 1.0 1.0 ndt 1.51633 1.51633
  • Example 6 Example 7 L 1.55 1.55 D 1.5 1.5 OB 1.426 1.079 d 1.0 1.0 ndt 1.51633 1.51633
  • the endoscope according to the present embodiment includes the endoscope optical system according to the present embodiment, an imaging element, an illumination unit, and an insertion unit having a holding member, and the imaging optical system and the illumination unit , And arranged inside the holding member.
  • FIG. 33 is a diagram showing an insertion portion of the endoscope.
  • the insertion section 230 has an endoscope optical system, an illumination section, and the holding member 11.
  • the endoscope optical system has a tip member 231 and a parallel flat plate 6.
  • the imaging optical system and the illumination unit are disposed inside the holding member 11. In FIG. 33, the imaging optical system and the illumination unit are not shown.
  • a forceps hole 232 is provided in the insertion section shown in FIG. Therefore, the endoscope optical system is arranged at a position away from the central axis of the insertion section.
  • a closed space is formed by the inner peripheral surface and the end surface of the holding member.
  • the enclosed space is filled with gas. Therefore, flare is likely to occur due to the illumination light reflected on the inner peripheral surface.
  • the endoscope according to the present embodiment includes the above-described endoscope optical system, the occurrence of flare can be suppressed.
  • an object located near the outer peripheral surface of the distal end optical system or an object in contact with the outer peripheral surface of the distal end optical system can be clearly observed.
  • the imaging optical system is treated as an optical system for forming an optical image of an object.
  • the imaging optical system can be used as a scanning optical system that scans illumination light.
  • the imaging optical system 3 shown in FIG. 1 can be used.
  • the imaging optical system 3 shown in FIG. 1 can be used.
  • light from one point on the object plane OB is condensed on one point on the image plane I. This means that, when the light source is arranged at one point on the image plane I, the light emitted from the light source is collected at one point on the object plane OB.
  • a point light source is arranged at the position of the image plane I.
  • one point on the object plane OB can be illuminated.
  • receiving light from one illuminated point it is possible to acquire information on one point on the object plane OB.
  • the light from the object plane OB may be provided, for example, by arranging a light receiving element at the location of the illumination unit.
  • the point light source may be moved, for example, by moving the end of one optical fiber in the plane of the image plane I.
  • the movement of the end of the optical fiber can be realized, for example, by disposing an actuator near the end of the optical fiber.
  • the movement trajectory of the optical fiber can be, for example, spiral.
  • the light source arranged at the position of the image plane I may be any light source as long as it can be regarded as a point light source. If the size of the light emitting surface of the optical fiber is large enough to be regarded as a point light source, the light emitting surface can also be called a point light source. For example, a single mode fiber can be used as the optical fiber.
  • the light exit surface of the fiber bundle may be arranged at the position of the image plane.
  • a plurality of optical fibers are bundled into one. By changing the optical fiber on which the illumination light is incident, the movement of the point light source can be realized without moving the optical fiber.
  • the distal end of the insertion portion has a connection portion
  • the distal end member has a connection portion
  • the distal end member can be attached to and detached from the insertion portion via the two connection portions. preferable.
  • a clear image can be obtained in the side viewing direction at the time of observation, even though the diameter of the insertion portion is small.
  • the distal end member can be attached to and detached from the insertion portion.
  • a tip optical system is located at one end of the tip member. Therefore, the tip optical system can also be attached to and detached from the insertion section.
  • the tip member can be replaced.
  • the distal end member may have the distal end optical system and the holding frame.
  • the tip optical system and the holding frame may be separable.
  • the shape, size, thickness, or material can be variously changed. Therefore, a plurality of tip members having different specifications can be prepared. By doing so, observation can be performed with the tip member suitable for observation.
  • the distal end member is always fixed to the distal end of the inner insertion portion.
  • a clear image can be obtained in the side viewing direction at the time of observation, even though the diameter of the insertion portion is small.
  • the imaging optical system can be protected from dirt and the like.
  • the endoscope system includes the endoscope described above, an image processing device, and a light source device.
  • FIG. 34 is a diagram showing an example of an endoscope and an example of an endoscope system.
  • FIG. 34A is a diagram illustrating a rigid endoscope
  • FIG. 34B is a diagram illustrating a flexible endoscope system.
  • an endoscope optical system 241 is disposed at the distal end of the insertion section of the endoscope 240.
  • the endoscope optical system of the present embodiment can be used for the endoscope optical system 241.
  • the insertion section has an image sensor.
  • an image in the side viewing direction can be obtained in all directions. Therefore, various parts can be imaged from an angle different from that of a conventional endoscope.
  • an endoscope optical system 251 is disposed at the distal end of the insertion section of the endoscope 250.
  • the endoscope optical system of the present embodiment can be used for the endoscope optical system 251.
  • the insertion section has an image sensor.
  • an image in the side viewing direction can be obtained in all directions. Therefore, various parts can be imaged from an angle different from that of a conventional endoscope.
  • the acquired image can be displayed on the display device 253 via the image processing device 252.
  • the image processing device 252 can perform various image processing.
  • the tip member may be exchangeable with respect to the insertion portion, or may be fixed to the insertion portion at all times.
  • the tip member When the tip member is detachable from the insertion portion, the tip member can be replaced. For example, if a plurality of tip members having different optical specifications are prepared, observation can be performed with a tip member suitable for observation.
  • the present invention includes the following inventions.
  • the inner peripheral surface includes a side surface of the truncated cone and a curved surface,
  • the curved surface has a part of the spherical surface and is located at one end of the inner peripheral surface,
  • An endoscope optical system characterized by satisfying the following conditional expression (5). 0mm ⁇ R0 ⁇ 0.5mm (5) here, R0 is the radius of curvature of the spherical surface, It is.
  • the tip member has a tip optical system,
  • the tip optical system has an inner peripheral surface and an outer peripheral surface, One end of the inner peripheral surface and one end of the outer peripheral surface are located on the optical axis of the imaging optical system, The position of one end of the inner peripheral surface is closer to the imaging optical system than the position of one end of the outer peripheral surface,
  • a tip member between an inner peripheral surface and an outer peripheral surface is filled with a transparent substance having a refractive index greater than 1.
  • P ′ is a Petzval sum and is represented by the following equation: r i is the radius of curvature of the i-th transmission surface, n ′ i is the refractive index on the exit side of the i-th transmission surface, ni is the refractive index on the incident side of the i-th transmission surface; n ′ is the refractive index of the image space, i is the number of the transmission surface, k is the total number of transmission surfaces, It is.
  • the present invention provides an endoscope optical system capable of clearly observing an object located near the outer peripheral surface of the tip optical system or an object in contact with the outer peripheral surface of the tip optical system. , Endoscope, and endoscope system.

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Abstract

L'invention concerne un système optique d'endoscope, un endoscope et un système d'endoscope, grâce auxquels un objet positionné à proximité de la surface circonférentielle externe d'un système optique d'extrémité ou un objet en contact avec la surface circonférentielle externe d'un système optique d'extrémité peut être clairement observé. Le système optique d'endoscope (1) comprend : un élément d'extrémité (2) relié à un élément de support (7) ; et un système optique de formation d'image (3) disposé dans l'élément de support (7). L'élément d'extrémité (2) comprend un système optique d'extrémité (4). Le système optique d'extrémité (4) comporte une surface circonférentielle interne (4b) et une surface circonférentielle externe (4a). Une extrémité de la surface circonférentielle interne (4b) et une extrémité de la surface circonférentielle externe (4a) sont positionnées sur l'axe optique du système optique de formation d'image (3). La position d'une extrémité de la surface circonférentielle interne (4b) est plus proche du système optique de formation d'image (3) que la position d'une extrémité de la surface circonférentielle externe (4a). La zone entre la surface circonférentielle interne (4b) et la surface circonférentielle externe (4a) est remplie d'une substance transparente présentant un indice de réfraction supérieur à 1 et, en conséquence de leur raccordement, un espace (5) rempli de gaz est formé entre la surface circonférentielle interne (4b) et le système optique de formation d'image (3). Le système optique de formation d'image (3) est caractérisé en ce qu'il comprend uniquement une surface de transmission, présentant une aberration de la courbure du champ, et en ce qu'il est conforme à la condition (1). -10 < P' < -0,8 (1)
PCT/JP2018/033382 2018-09-10 2018-09-10 Système optique d'endoscope, endoscope et système d'endoscope WO2020053922A1 (fr)

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004096028A1 (fr) * 2003-04-25 2004-11-11 Olympus Corporation Endoscope a capsule et systeme d'endoscope a capsule
JP2005080790A (ja) * 2003-09-05 2005-03-31 Olympus Corp カプセル型内視鏡
JP2005528182A (ja) * 2002-06-06 2005-09-22 オプティスコープ テクノロジーズ リミテッド 内視鏡のための光学装置
US20070129719A1 (en) * 2005-05-26 2007-06-07 Amar Kendale Apparatus and methods for performing minimally-invasive surgical procedures
JP2010246906A (ja) * 2009-03-24 2010-11-04 Fujifilm Corp カプセル型内視鏡用撮像光学系
JP2012132958A (ja) * 2010-12-20 2012-07-12 Canon Inc 撮像装置
JP2014089334A (ja) * 2012-10-30 2014-05-15 Panasonic Corp 内視鏡用レンズユニットおよびこれを備えた内視鏡
JP2015127741A (ja) * 2013-12-27 2015-07-09 パナソニックＩｐマネジメント株式会社 内視鏡カメラ用レンズ及び内視鏡カメラ

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005528182A (ja) * 2002-06-06 2005-09-22 オプティスコープ テクノロジーズ リミテッド 内視鏡のための光学装置
WO2004096028A1 (fr) * 2003-04-25 2004-11-11 Olympus Corporation Endoscope a capsule et systeme d'endoscope a capsule
JP2005080790A (ja) * 2003-09-05 2005-03-31 Olympus Corp カプセル型内視鏡
US20070129719A1 (en) * 2005-05-26 2007-06-07 Amar Kendale Apparatus and methods for performing minimally-invasive surgical procedures
JP2010246906A (ja) * 2009-03-24 2010-11-04 Fujifilm Corp カプセル型内視鏡用撮像光学系
JP2012132958A (ja) * 2010-12-20 2012-07-12 Canon Inc 撮像装置
JP2014089334A (ja) * 2012-10-30 2014-05-15 Panasonic Corp 内視鏡用レンズユニットおよびこれを備えた内視鏡
JP2015127741A (ja) * 2013-12-27 2015-07-09 パナソニックＩｐマネジメント株式会社 内視鏡カメラ用レンズ及び内視鏡カメラ

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