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WO2015015996A1 - Système optique d'éclairage pour endoscope - Google Patents

Système optique d'éclairage pour endoscope Download PDF

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Publication number
WO2015015996A1
WO2015015996A1 PCT/JP2014/067737 JP2014067737W WO2015015996A1 WO 2015015996 A1 WO2015015996 A1 WO 2015015996A1 JP 2014067737 W JP2014067737 W JP 2014067737W WO 2015015996 A1 WO2015015996 A1 WO 2015015996A1
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WIPO (PCT)
Prior art keywords
light guide
axis direction
optical system
lens
axis
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PCT/JP2014/067737
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English (en)
Japanese (ja)
Inventor
五十嵐　勉
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Olympus Medical Systems Corp
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Olympus Medical Systems Corp
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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
    • A61B1/06—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 with illuminating arrangements
    • 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
    • G02B23/2407—Optical details
    • G02B23/2461—Illumination
    • 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
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/02—Simple or compound lenses with non-spherical faces
    • G02B3/06—Simple or compound lenses with non-spherical faces with cylindrical or toric faces

Definitions

  • the present invention relates to an endoscope illumination optical system applied to a medical endoscope.
  • the observation space is filled with urine, and a relatively transparent visual field is secured by perfusing a perfusate such as physiological saline. Since the perfusate and urine are mainly water, and the concentration of salt, sugar, etc. is not so high, the refractive index can be considered to be equivalent to that of water. Therefore, in an endoscope for observing these organs, the optical specifications and performance at the time of underwater observation in which the object-side medium is regarded as water affects the practicality.
  • the most important point for the endoscope illumination optical system for underwater observation is the narrowing of the underwater angle of view with respect to the air.
  • the d-line refractive index of water is 1.333 at room temperature, and the relationship between the angle of view in air and the angle of view in water when the outer surface of the endoscope illumination optical system is a flat surface is shown below.
  • Angle of view in air 180 ° 160 ° 140 ° 120 °
  • JP 60-243623 A Japanese Patent Laid-Open No. 11-326786 JP 2008-237790 A JP 2009-207529 A Utility Model Registration No. 2572930 International Publication No. 2010/113550 JP-A-6-273678 Japanese Patent Laid-Open No. 5-203882
  • each of the above-mentioned patent documents can be mounted on a small-diameter endoscope with a channel such as that for a bladder, and is not sufficient as an illumination optical system corresponding to wide-angle underwater observation.
  • the present invention has been made in view of the above-described circumstances, and can provide good light distribution even when the underwater angle of view is wide, and illumination optics suitable for mounting on a thin medical endoscope. The purpose is to provide a system.
  • One aspect of the present invention includes a light guide provided at the distal end of an insertion portion of an endoscope, and an illumination lens disposed adjacent to the object side of the light guide, and the distal end side end surface of the light guide has a long length.
  • the light guide side surface of the illumination lens is a concave surface having an effective range equal to or greater than the shape of the end surface of the light guide, and the concave surface is a toric surface.
  • An illumination optical system that is either an anamorphic surface or an elliptical surface and satisfies the following conditional expression is provided.
  • L L is the maximum length in the long axis direction of the end surface on the light guide front end side
  • L S is the maximum length in the short axis direction on the end surface on the light guide front end side
  • R L is the central curvature of the lens concave surface in the long axis direction.
  • the radius is an absolute value
  • RS is the absolute value of the center curvature radius in the minor axis direction of the concave lens surface.
  • the degree of freedom of arrangement of the structure at the distal end of the insertion portion is increased. It can be made easier to optimize the mounting efficiency.
  • Various polygonal and curved surface configurations can be applied as non-circular shapes having a difference in length between the major axis and the minor axis. Note that an elliptical shape is conceivable as a representative example of the shape in which the definition of the shape is easy and the light guide can be easily molded.
  • the light guide exit light can be diffused to ensure wide-angle light distribution.
  • various problems caused by making the light guide side surface of the illumination lens convex can be avoided.
  • the surface on the light guide side is a convex surface
  • the light energy density is increased in the vicinity of the condensing point, so that there is a problem in ensuring thermal safety for the living body.
  • a transparent resin-molded illumination lens optimal for mounting a special lens shape has a problem in the thermal durability of the resin itself in the vicinity of the condensing point.
  • unevenness due to a mesh pattern formed by a large number of optical fibers constituting the light guide is easily caused by the convex imaging function.
  • the concave surface is given a non-axisymmetric shape so that it can be optimally combined with a light guide having a non-axisymmetric cross-sectional shape.
  • Equation (1) indicates that the absolute value R S of the central curvature radius of the concave surface of the lens concave surface is sufficiently small with respect to the maximum length L S of the light guide in the short axis direction, thereby sufficiently distributing the light in the short axis direction.
  • the light guide end surface is mainly responsible for the light distribution in the lateral direction of the image having a horizontally long aspect ratio, and the light guide end surface is preferentially widened in the short axis direction. .
  • the required light distribution is even more severe than in wide-angle observation in the air, so it is important to increase the diffusivity as much as possible. It becomes.
  • a concave surface covering the entire length of L S can be formed by setting R S / L S to less than 0.5 and making it an aspheric surface whose curvature is weakened at the peripheral part. .
  • R S / L S which is less than the lower limit of the conditional expression is 0.3 or less, it is inevitably an aspheric surface, but the curvature is weakened around the concave surface having a high area ratio. This is not desirable because it is difficult to realize. If R S / L S is 0.7 or more, the concave power at the center of the concave surface is weak, contrary to the above, and it is not desirable because wide-angle light distribution in water cannot be obtained.
  • Equation (2) is a condition that defines the balance between light distribution in the short axis direction and light distribution in the long axis direction.
  • the smaller the value of R S / L S involved in light distribution in the short axis direction, the better the light diffusibility, and R L / L L involved in light distribution in the long axis direction has the same function. Therefore, when (R L / L L ) / (R S / L S ) 1, the diffusibility in the minor axis direction and the major axis direction are substantially equal, and when less than 1, the diffusibility in the major axis direction is relatively High and exceeding 1 means that the diffusibility in the long axis direction is relatively low.
  • priority is given to ensuring light distribution in the short axis direction, which mainly corresponds to the horizontal direction of the horizontally long image, and the priority of light distribution is lowered in the long axis direction, and the effective range of the entire concave surface is the most efficient on the light guide end surface.
  • Priority is given to a well-covered shape.
  • the concave shape in the plane where the illumination lens concave surface abuts the light guide is not necessarily an ellipse, and the short axis direction and the long axis
  • the concave surface may not be able to cover the light guide in an orientation different from the direction. Therefore, R L / L L is set to a value larger than R S / L S, and it is possible to obtain an appropriate light distribution with respect to the light distribution in the long axis direction while eliminating the insufficient effective diameter of the concave surface in the orientation other than the short axis direction.
  • the lower limit of the formula (2) it is not desirable because the problem of insufficient effective diameter of the concave surface occurs.
  • the upper limit of the formula (2) is exceeded, the light distribution in the major axis direction is insufficient.
  • the concave surface of the illumination lens is preferably a rough surface. In this way, further diffusibility can be obtained. That is, since the required light distribution increases as the underwater angle of view increases, there is a limit to relying on only the diffusivity of the concave surface when the underwater angle of view is very large. Therefore, further diffusibility can be obtained by using a rough surface having minute irregularities while maintaining the concave shape of the illumination lens.
  • the front end side end surface of the said light guide is a rough surface.
  • the light distribution improvement effect can be obtained by the same operation even if the end surface on the front end side of the light guide is made rough instead of making the illumination lens rough.
  • the end face can be roughened by machining such as sandblasting to make it rough.
  • the end surface on the front end side of the light guide has a repeatable Z-axis direction displacement in the L-axis-Z-axis cross section.
  • One problem with rough surfaces is that it is easy to develop trial and error because modeling in optical design and simulation prediction are difficult. For this reason, if a shape that can be modeled in optical design is given to the end face on the front end side of the light guide that still has the degree of freedom in shape design, light distribution can be improved based on simulation prediction.
  • the thin plate-shaped diffusion member is arrange
  • the light guide includes an objective optical system, a channel, and any one of the illumination optical systems described above, and the axis connecting the objective optical system and the center of the channel is a C axis.
  • the major axis of the end surface on the front end side has an inclination of 30 ° or less with respect to the C-axis, and the illumination optical system is arranged in each of two regions divided by the C-axis.
  • L L is the maximum length of the long axis direction of the light guide distal end side end surface
  • L S is the maximum length of the short axis direction of the distal end side end face of the light guide
  • R L is the lens concave axial direction center
  • the radius of curvature is an absolute value
  • R S is the absolute value of the center radius of curvature of the concave surface of the lens in the minor axis direction.
  • the light guide cross section on the distal end side of the insertion part into a non-circular shape having a major axis and a minor axis, it is possible to increase the degree of freedom of arrangement of the structure at the distal end of the insertion part and facilitate optimization of the mounting efficiency.
  • the surface on the light guide side concave, light emitted from the light guide can be diffused to ensure wide-angle light distribution.
  • an illumination optical system that can provide a good light distribution even when the underwater angle of view is wide and is suitable for mounting on a medical endoscope having a small diameter.
  • Example 1 of this invention it is a graph which shows the spherical surface light distribution of the light radiate
  • Example 2 of this invention it is a graph which shows the spherical surface light distribution of the light radiate
  • Example 3 of this invention it is a graph which shows the spherical surface light distribution of the light radiate
  • Example 5 of this invention it is a graph which shows the spherical surface light distribution of the light radiate
  • Example 7 of this invention it is a graph which shows the spherical surface light distribution of the light radiate
  • FIG. 1 is a perspective view when the distal end portion 1 of the insertion portion in the endoscope according to the present embodiment is observed from the object side.
  • the distal end portion 1 of the insertion portion has a substantially circular cross section and has a configuration in which various components are accommodated in a distal end frame 8 made of a transparent resin molded product.
  • the distal end portion 1 includes a light guide 2, an illumination lens 3, an objective optical system 4, an objective lens frame 4 ⁇ / b> A, a solid-state imaging device 5, a channel 6, and an angle wire 7 in a distal end frame 8.
  • the light guide 2 when the solid-state imaging device 5 and the channel 6, which are structures having a relatively large cross-sectional area, are arranged vertically within the diameter of the tip portion 1, the light guide 2 can be arranged only in the left and right spaces. Therefore, the light guide 2 divided into two on the tip side is arranged. That is, when the axis connecting the center of the objective optical system 4 and the channel 6 is the C axis, one or more light guides 2 are arranged in each of the two areas divided by the C axis. Moreover, the front end side end surface of the light guide has a non-circular shape having a long axis (L axis) and a short axis (S axis). Details of the end face shape of the light guide will be described later.
  • L axis long axis
  • S axis short axis
  • the illumination lens 3 is configured such that a portion of the distal end frame 8 facing the light guide 2 is an illumination lens. Further, there is an effective range of the front surface of the illumination lens in terms of optical design.
  • the surface disposed on the light guide 2 side of the illumination lens 3 is a concave surface having an effective range equal to or greater than the end surface shape of the light guide 2.
  • the concave surface is preferably a toric surface, an anamorphic surface, or an elliptical surface. Details of the concave shape of the illumination lens will be described later.
  • the objective optical system 4 is held by an objective lens frame 4A, and a solid-state imaging device 5 is disposed on the proximal end side of the objective optical system 4 in the insertion portion.
  • the solid-state imaging device 5 outputs an image having a horizontally long aspect ratio.
  • the signal cable (not shown), the light guide 2 and the channel 6 connected to the solid-state imaging device 5 affect the layout over the entire length of the insertion portion.
  • the channel 6 is a communication hole through which various treatment tools such as forceps are inserted, and the angle wire 7 is a bending mechanism for appropriately bending the distal end portion.
  • the front end frame that holds each structure at the front end portion 1 is made of a transparent resin molded product so as to also function as an illumination lens.
  • FIG. 2 is a cross-sectional view of the tip 1 in the optical axis direction, that is, a cross-sectional view of the tip 1 cut along a C-axis connecting the center of the channel 6 and the center of the objective optical system 4.
  • the channel 6 and the objective lens frame 4 ⁇ / b> A are fixed to the distal end frame 8.
  • the channel opening 9 is inclined so that the distal end frame 8 is tapered in consideration of improved insertion into the urethra and the like.
  • the light guide 2 and the effective range of the front end surface of the illumination lens are disposed relatively lower.
  • FIG. 3 is a view of the tip portion 1 when observed obliquely from the object side.
  • the tip frame 8 has an inclination of the channel opening 9, but the illumination lens tip surface effective range 3 is also inclined in order to taper for the purpose of improving the insertion property.
  • the shape of the distal end surface of the distal end frame 8 from the viewpoint of improving the insertability needs to be taken into consideration when arranging the components, and the illumination lens 3 includes the shape of the inclined surface including the effective range of the distal end surface of the illumination lens 3.
  • the arrangement shown in FIG. 1 is obtained by optimizing the tip end face effective range and the light guide 2.
  • the light guide 2 is an ellipse having a long axis inclined by 20 ° with respect to an axis (C axis) passing through the center of the channel 6 and the center of the objective lens frame, and the effective range of the front end surface of the illumination lens 3 has the same orientation. Assume an ellipse with. In the embodiment, the inclination angle of the effective range of the front end surface of the illumination lens 3 is 15 ° in the light guide minor axis direction.
  • the end face of the light guide 2 on the distal end side has a non-circular shape having a long axis (L axis) and a short axis (S axis), thereby increasing the degree of freedom of arrangement of the structure at the distal end of the insertion section and optimizing the mounting efficiency. It is easy to change.
  • Various non-circular shapes with different lengths between the major axis and minor axis may have various polygonal and curved surface configurations, but an ellipse shown in FIG. 1 is representative as an example of easy shape definition and light guide molding. Is. Therefore, the following description will be made using an ellipse.
  • the ellipse can be expressed by the following equation (3) as is widely known.
  • a LG is the radius of the elliptical light guide in the X-axis direction
  • bLG is the radius of the elliptical light guide in the Y-axis direction.
  • minor axis 2 times the maximum length L S in the minor axis direction.
  • the major and minor radii are appropriately set with the elliptical light guide defined above, rotated in an arbitrary direction with respect to the insertion axis, and then placed in the absolute coordinate system of the insertion space.
  • the endoscope according to the present embodiment has a light distribution in comparison with a general endoscope having an angle of view in air exceeding 180 °, an angle of view in water of 100 ° or more, and an angle of view in air of less than 170 °.
  • the demand for is severe.
  • the reason why the surface on the light guide 2 side of the illumination lens 3 is concave is that the light on the light guide 2 side of the illumination lens 3 is convex while diffusing the light emitted from the light guide 2 to ensure wide-angle light distribution. This is to avoid various problems caused by this.
  • the surface on the light guide 2 side of the illumination lens 3 is a convex surface
  • the light energy density is increased in the vicinity of the condensing point, so that there is a problem in ensuring thermal safety for the living body.
  • a transparent resin-molded illumination lens optimal for mounting a special lens shape has a problem in the thermal durability of the resin itself in the vicinity of the condensing point.
  • unevenness due to the mesh pattern formed by a large number of optical fibers constituting the light guide by the imaging action of the convex surface is likely to occur. Due to these problems, the convex surface cannot provide the strong power necessary to secure the wide-angle light distribution, and a light distribution that can be used for wide-angle observation during underwater observation cannot be obtained.
  • the configuration of the present invention employs a concave surface that is difficult to cause these problems. Further, the concave surface is given a non-axisymmetric shape, and can be optimally combined with a light guide having a non-axisymmetric cross-sectional shape.
  • the toric surface is generally defined as a surface that occurs when a circle is rotated about a straight line that does not pass through its center. Further, there is an aspheric toric as a surface generated when an axisymmetric aspheric surface is rotated about a straight line that does not pass through the center of curvature of the central portion. In the present invention, an aspheric toric is also treated as a kind of toric surface.
  • the optical axis direction is the Z axis
  • the two axes perpendicular to and perpendicular to the Z axis are the X axis and the Y axis
  • the spherical surface or the axisymmetric aspheric surface in the YZ section is the radius of curvature in the XZ section.
  • the formula for defining the toric surface when rotated with respect to the Y axis by RX is shown in Formula (4).
  • X is the X coordinate
  • Y is the Y coordinate
  • Z (X, Y) is the Z coordinate obtained as a function of X and Y
  • RX is the central radius of curvature in the XZ section
  • RY is in the YZ section.
  • KY is a coefficient that determines the quadratic curved surface characteristics in the YZ section
  • n is an integer of 2 or more
  • AY 2n is the coefficient for each order of the aspheric polynomial term in the YZ section. .
  • the toric surface has two symmetric cross sections, and in the definition of Equation (4), it is symmetric with respect to the Z axis in the XZ cross section, and symmetric with respect to the Z axis in the YZ cross section. Further, the shape in the XZ cross section is a circle having a radius RX.
  • the anamorphic surface has two symmetrical cross sections like the toric surface, but does not have a rotation axis like the toric surface and can express a shape different from the toric surface.
  • the formula for defining the anamorphic surface is shown in Formula (5).
  • the coordinate system is the same as that defined on the toric surface.
  • KX is a coefficient that determines the quadratic surface characteristics in the XZ cross section
  • KY is a coefficient that determines the quadric surface characteristics in the YZ cross section
  • AR 2n is a coefficient by degree of the aspheric polynomial term in both XY directions.
  • AP 2n is a coefficient by order of the aspheric polynomial term, and is a coefficient that varies the action in the XY directions.
  • the ellipsoidal surface is well known optically as a reflector for a light source optical system.
  • the ellipsoidal surface is defined by an ellipsoidal definition formula, and the formula (6) shows a result of converting it into a plane shape definition for optical design.
  • a is the radius of the ellipsoid in the X-axis direction
  • b is the radius of the ellipsoid in the Y-axis direction
  • c is the radius of the ellipsoid in the Z-axis direction.
  • the elliptical surface can be set by deleting the even-order polynomial part in the mathematical formula (3) of the anamorphic surface and performing parameter substitution of the following mathematical formula (7) It is.
  • the ellipsoid can be treated as a kind of anamorphic surface.
  • the illumination optical system preferably satisfies the following conditional expression. 0.3 ⁇ R S / L S ⁇ 0.7 (8) 1 ⁇ (R L / L L ) / (R S / L S ) ⁇ 5 (9)
  • L L is the maximum length in the long axis direction of the end surface on the light guide front end side
  • L S is the maximum length in the short axis direction on the end surface on the light guide front end side
  • R L is the central curvature of the lens concave surface in the long axis direction.
  • the radius is an absolute value
  • RS is the absolute value of the center curvature radius in the minor axis direction of the concave lens surface.
  • Equation (8) is such that the absolute value R S of the central curvature radius in the minor axis direction of the concave surface of the lens is sufficiently small with respect to the maximum length L S in the minor axis direction of the light guide, thereby sufficiently distributing the light in the minor axis direction. This is a condition for widening.
  • the minor axis direction of the light guide end face mainly bears the lateral light distribution of an image having a horizontally long aspect ratio, and the light guide end face light distribution in the minor axis direction is preferentially widened. The configuration.
  • the state is ideal.
  • the concave minor axis direction cross-section of the aspherical surface can form a concave surface which covers the L S entire length by an aspherical surface curvature is weakened at the periphery on which is less than 0.5 R S / L S .
  • R S / L S which is less than the lower limit of the conditional expression is 0.3 or less, it is inevitably an aspheric surface, but the curvature is weakened around the concave surface having a high area ratio. This is not desirable because it is difficult to realize. If R S / L S is 0.7 or more, the concave power at the center of the concave surface is weak, contrary to the above, and it is not desirable because wide-angle light distribution in water cannot be obtained.
  • Equation (9) is a condition that regulates the balance between light distribution in the short axis direction and light distribution in the long axis direction.
  • R S / L S related to light distribution in the short axis direction has a better light diffusibility as the value is smaller, and R L / L L related to light distribution in the long axis direction.
  • priority is given to light distribution in the short axis direction corresponding mainly to the horizontal direction of the horizontally long image, the priority of light distribution is lowered in the long axis direction, and the effective range of the entire concave surface covers the light guide end surface most efficiently.
  • Priority is given to shape.
  • R L / L L is set to a value larger than R S / L S, and it is possible to obtain an appropriate light distribution with respect to the light distribution in the long axis direction while eliminating the insufficient effective diameter of the concave surface in the orientation other than the short axis direction.
  • the effective diameter of the concave surface is insufficient, and it is not desirable, and above the upper limit of the formula (9), the light distribution in the major axis direction is insufficient, which is not desirable.
  • the concave surface or light guide end surface of the illumination lens 3 on the light guide side is a rough surface. Since the required light distribution increases as the underwater angle of view increases, there is a limit to relying solely on the diffusivity of the concave surface when the underwater angle of view is very large. By making the concave surface of the illumination lens a rough surface having minute irregularities while maintaining the shape, further diffusibility can be obtained.
  • the rough surface can be formed on the illumination lens by transferring the rough surface formed on the mold.
  • the glass surface can be processed directly by machining or chemical treatment. Furthermore, by using a glass mold, it is possible to transfer a rough mold shape to glass. Note that it is also possible to selectively improve the diffusivity in the long axis direction by using, for example, a rough surface as a streak running in the short axis direction by utilizing the fact that the illumination lens is non-axisymmetric.
  • the light distribution improvement effect can be obtained by the same action when the front end side surface of the light guide is made rough instead of making the illumination lens rough.
  • machining such as sandblasting may be performed to make the end surface rough.
  • the light guide end face has a repetitive Z-direction displacement in the L-axis-Z-axis cross section.
  • a thin plate-like diffusing member between the end face of the light guide and the illumination lens.
  • Various methods are known as a method for forming the diffusing member, but a typical one is to make at least one surface of glass processed into a thin plate into a rough surface. There is a rough surface forming method. When a transparent resin material is used, transfer by molding is easy.
  • the light distribution angle there is a degree of freedom in which the light distribution angle can be designed, and a holographic material in which fine particles of a light diffusing agent are added inside the resin and a fine uneven pattern formed by a surface relief hologram Diffuser can be used.
  • a holographic material in which fine particles of a light diffusing agent are added inside the resin and a fine uneven pattern formed by a surface relief hologram Diffuser can be used.
  • the holographic diffusion plate it is possible to obtain light distribution characteristics having anisotropy.
  • an illumination optical system that can obtain a good light distribution even when the underwater angle of view is wide and is suitable for mounting on a small-sized medical endoscope.
  • FIG. 4 shows the configuration of an objective optical system in an endoscope to which the illumination optical system according to each embodiment is applied.
  • 4A shows the objective optical system in the underwater observation state
  • FIG. 4B shows the objective optical system in the air observation state.
  • the objective optical system in FIG. 4 includes, in order from the object side, a first group (first lens) composed of plano-concave lenses, a second group composed of plano-concave lenses, a color correction filter, an aperture stop that is assumed to be mounted on a thin plate, A rear group having a refractive power of The rear group consists of three groups, all having positive refractive power. It is assumed that the imaging surface of the solid-state imaging device is disposed on the image surface.
  • the image height Iw in the underwater observation state in FIG. 4A is 0.751 mm, and it is assumed that this image height matches the effective image pickup area of the solid-state image pickup device. Use the entire imaging area.
  • the underwater angle of view at this time is 129.4 °, which is a very wide angle for underwater observation, and an object in water can be observed using the entire effective image pickup area of the solid-state image sensor.
  • FIG. 5 is a conceptual diagram showing the imaging range of underwater observation and in-air observation, and intuitively shows that the effective imaging area in the in-air observation state becomes narrower than in the underwater observation state as described above.
  • FIG. 5A shows an imaging area on a solid-state imaging device in an underwater observation state, and shows that an effective imaging area in a hatched octagonal mask can be used on the assumption that an octagonal electric field mask is attached.
  • the maximum image height in the octagonal mask is Iw.
  • FIG. 5B shows the imaging area on the solid-state imaging device in the air observation state, and the hatched circle of radius Ia becomes the imaging area in the air observation state, and is hatched between the octagonal mask and the circle.
  • the no area is an optically ineffective area where no subject image is formed.
  • Such an objective optical system enables wide-angle observation in an underwater state even when the object side is in a flat state. Furthermore, the fact that the object side is a flat surface does not require any special contrivance for direct light incident flare from the illumination optical system, and does not cause any additional restrictions on the configuration of the illumination optical system.
  • the lens having the maximum lens outer diameter in the objective optical system is ⁇ 2.2 mm at the lens on the object side end, and even when combined with a channel and a bending mechanism having an inner diameter ⁇ 2.2 mm required for a cystoscope, the tip outer diameter is less than ⁇ 7 Can be realized.
  • the lens data of the objective optical system in FIG. 4 is shown below.
  • r represents a radius of curvature (unit: mm)
  • d represents a surface interval (mm)
  • Nd represents a refractive index with respect to the d line
  • Vd represents an Abbe number with respect to the d line.
  • Image height and angle of view for underwater observation Image height [mm] Angle of view [°] Diagonal 0.751 129.4 Horizontal 0.706 118.7 Vertical 0.482 76.3
  • Tables 1 and 2 show various data of the illumination optical system according to each example.
  • the major axis direction of the ellipse is Y of concave local coordinates
  • the minor axis direction is X of concave local coordinates.
  • each of the light guides applied to each example has an elliptical end face shape
  • the rotation direction of the major axis with respect to the C axis connecting the objective optical system and the center of the channel is 20 ° (see FIG. 1)
  • the central coordinates with respect to the objective optical system center are (2.067, 0.752), ( -2.067, 0.752).
  • the comparative example is a combination of a circular light guide and a concave spherical lens that can be mounted in the same space as each example, and the object surface center illuminance is at the same level as each example having the lowest illuminance.
  • the light guide of the comparative example has a circular shape, the radius is 0.37 mm (the same as the short radius of each example), and the center coordinate [mm] with respect to the objective optical system center is (2.067, 0.752). ), ( ⁇ 2.067, 0.752).
  • the illumination lens of the comparative example has the same material, outer surface side shape, center thickness, and outer surface side effective diameter as those of the respective examples.
  • emitted in water from the illumination lens of a comparative example was shown in FIG.
  • FIG. 7 to 20 show the sectional shape of the illumination lens of each example and a spherical light distribution graph of light emitted into water.
  • (a) shows a cross section in the short axis direction of the light guide
  • (b) shows a cross section in the long axis direction of the light guide.
  • the spherical light distribution graph is obtained by standardizing the illuminance distribution by ray bundle tracking and intensity integration, assuming that a sphere having a radius of 40 mm is disposed at a distance of 40 mm in water.
  • FIG. 6 shows the light distribution of the light guide emitted light used for intensity integration.
  • Example 7 is a kinoform shape having periodicity.
  • FIG. 22 is a diagram showing the shape of the light guide end face of Example 7, which has a saw blade-like pattern with an orientation such that the boundary line runs in the minor axis direction, and diffuses light in the major axis direction.
  • the cross-sectional shape has an inclination angle of 16.7 ° and a depth of 0.045 mm.
  • the concave surfaces of the illumination lens are toric surfaces in Examples 1 to 2 and 7, anamorphic surfaces in Examples 3 to 5, and elliptical surfaces in Example 6.
  • the concave shape in all these examples assumes a visual field slightly inside the underwater horizontal angle of view (118.7 °) and the underwater vertical angle of view (76.3 °) of the objective optical system. It is designed to obtain a spherical light distribution (ratio to the center). Underwater 55 ° spherical light distribution in the horizontal direction of the screen: 10% or more Underwater 35 ° spherical light distribution in the vertical direction of the screen: 25% or more
  • each of these embodiments satisfies the expressions (8) and (9), and enhances the diffusibility in the minor axis direction of the light guide with a small mounting space despite a wide angle of view to be supported.
  • the target light distribution is obtained.
  • the comparative example consisting of a circular light guide and a concave spherical lens has a horizontal light distribution in spite of the same level as in Example 2 where the central illumination ratio is the lowest in the examples.
  • the target has been largely missed.
  • the concave curvature radius of the comparative example is made smaller, the horizontal light distribution can be improved. In this case, however, the central illuminance is lowered, which causes a problem in brightness.
  • the configuration of the present invention is not used, it is difficult to ensure illumination performance in a limited tip space.
  • Example 1 and Example 7 have the same illumination lens shape and differ only in the shape of the light guide end surface, and thus the difference in light distribution performance is due to the shape of the light guide end surface in the form of a kinoform.
  • the light distribution of Example 7 is improved mainly in the vertical direction, and the light diffusion effect in the light guide major axis direction appears.
  • each embodiment it is possible to provide an illumination optical system that can obtain a good light distribution even when the underwater angle of view is wide and is suitable for mounting on a small-sized medical endoscope.

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Abstract

La présente invention concerne un système optique d'éclairage qui permet d'obtenir une distribution favorable de la lumière, même lorsque l'ange de vue dans l'eau est large et qui est apte à être mis en œuvre dans des endoscopes médicaux de petit diamètre. Le système optique d'éclairage est doté d'un guide de lumière disposé sur la pointe de la section insérée de l'endoscope et d'une lentille d'éclairage disposée à proximité du guide de lumière sur le côté objet. La face d'extrémité de l'extrémité avant du guide de lumière présente une forme en section transversale non circulaire ayant un axe principal et un axe secondaire. La surface côté guide de lumière de la lentille d'éclairage est une surface concave ayant une zone efficace qui est égale ou supérieure à la forme en section transversale du guide de lumière. La surface concave est une surface torique, une surface anamorphique ou une surface elliptique et répond aux formules conditionnelles suivantes : 0,3 < (RS)/(LS) < 0,7 --- (1) 1 < (RL/LL)/(RS/LS) < 5 --- (2) (LL) est la longueur maximum de la face d'extrémité de l'extrémité avant du guide de lumière dans la direction de l'axe principal. (LS) est la longueur maximum de la face d'extrémité de l'extrémité avant du guide de lumière dans la direction de l'axe secondaire. (RL) est la valeur absolue du rayon central de la courbure de la surface de lentille concave dans la direction d'axe principal. (RS) est la valeur absolue du rayon central de la courbure de la surface de lentille concave dans la direction d'axe secondaire.
PCT/JP2014/067737 2013-07-30 2014-07-03 Système optique d'éclairage pour endoscope Ceased WO2015015996A1 (fr)

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WO2017043170A1 (fr) * 2015-09-09 2017-03-16 オリンパス株式会社 Système optique d'éclairage d'endoscope
CN108802867A (zh) * 2017-04-28 2018-11-13 富士胶片株式会社 照明用透镜及内窥镜用照明光学系统
WO2019059160A1 (fr) 2017-09-22 2019-03-28 東レ株式会社 Fibre optique en plastique pour éclairage de dispositif médical et éclairage de dispositif médical l'utilisant
JP2019130155A (ja) * 2018-02-01 2019-08-08 株式会社フジクラ 内視鏡
JPWO2021039221A1 (fr) * 2019-08-27 2021-03-04
US11234580B2 (en) 2016-06-17 2022-02-01 Olympus Corporation Endoscope illuminating optical system

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CN107529952A (zh) * 2015-09-09 2018-01-02 奥林巴斯株式会社 内窥镜照明光学系统
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JPWO2021039221A1 (fr) * 2019-08-27 2021-03-04
US12092809B2 (en) 2019-08-27 2024-09-17 Fujifilm Corporation Illumination optical system for endoscope

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