JP7339912B2 - Illumination optical system for endoscope and endoscope - Google Patents

Description

The present invention relates to an endoscope illumination optical system in which a plurality of optical fibers are bundled by a base, and an endoscope including an endoscope illumination optical system in which a plurality of optical fibers are bundled by a base.

BACKGROUND ART Endoscopes are widely used in which an insertion section is inserted into a body cavity of a subject, an image is acquired by an imaging device arranged at the distal end, or a treatment is performed using a treatment instrument protruding from the distal end. It is An illumination optical system is indispensable for observing inside body cavities where external light cannot reach.

Illumination light generated by the light source is guided by a fiber bundle formed by bundling a plurality of optical fibers, and emitted from an illumination optical system provided at the tip. In the illumination optical system, the illumination light heats the fiber bundle and the illumination optical system, so the temperature at the tip of the endoscope tends to rise. In recent years, as the density and number of pixels of image sensors have increased, the temperature of the tip of the endoscope has increased (heat generation).

Japanese Unexamined Patent Application Publication No. 2006-323077 discloses a method of bundling a fiber bundle of a plurality of optical fibers with a spinneret and then reducing the diameter of the spinneret by drawing.

JP 2006-323077 A

An object of the embodiments of the present invention is to provide an endoscope illumination optical system that is highly reliable and hardly generates heat, and an endoscope that includes the endoscope illumination optical system that is highly reliable and hardly generates heat. do.

An illumination optical system for an endoscope according to an embodiment includes a plurality of optical fibers, a fiber bundle that guides light, a base into which the distal end of the fiber bundle is inserted and that bundles the plurality of optical fibers, a resin that fills spaces between the plurality of optical fibers at the tip portion; and an illumination optical system that receives the light emitted from the tip surface of the fiber bundle and emits the light from an emission surface. and the inner diameter of the tip of the mouthpiece is smaller than the inner diameter of the proximal end.

Further, an endoscope of another embodiment includes an endoscope illumination optical system, wherein the endoscope illumination optical system is composed of a plurality of optical fibers, and includes a fiber bundle for guiding light and the fiber A base into which the tip portion of the bundle is inserted, bundling the plurality of optical fibers, a resin filling spaces between the plurality of optical fibers at the tip portion, and the fiber bundle emitted from the tip surface of the fiber bundle. an illumination optical system that receives light and emits the light from an exit surface, wherein the inner diameter of the tip of the base is smaller than the inner diameter of the base.

ADVANTAGE OF THE INVENTION According to the embodiment of the present invention, it is possible to provide an endoscope illumination optical system that is highly reliable and less likely to generate heat, and an endoscope including the endoscope illumination optical system that is highly reliable and less likely to generate heat.

1 is a configuration diagram of an endoscope system including an endoscope according to an embodiment; FIG. 1 is a cross-sectional view of an illumination optical system according to a first embodiment; FIG. 3 is a cross-sectional view along line III-III of FIG. 2 of the illumination optical system of the first embodiment; FIG. FIG. 4 is a cross-sectional view for explaining a method of manufacturing the illumination optical system of the first embodiment; FIG. 4 is a cross-sectional view of an illumination optical system of Modification 1 of the first embodiment; FIG. 11 is a cross-sectional view of an illumination optical system of Modification 2 of the first embodiment; FIG. 5 is a cross-sectional view of an illumination optical system of a second embodiment; FIG. 3 is a diagram showing spectral reflectance of an antireflection film;

<Endoscope>
As shown in FIG. 1, the endoscope 9 of the embodiment includes, for example, a processor 92 for processing imaging signals, a monitor 93, an input device 94 for setting usage conditions and the like, and a light source device 95. An endoscope system 8 is configured.

In the following description, the drawings based on the embodiments etc. are schematic, and the relationship between the thickness and width of each part, the ratio of the thickness of each part, the relative angle, etc. different. Even between the drawings, there are portions with different dimensional relationships and ratios. Illustration of some components is omitted.

The endoscope 9 includes an elongated insertion section 60 to be inserted into the body, and a universal cord 61 that is arranged from the insertion section 60 with an operation section (not shown) interposed therebetween. Universal cord 61 is connected to processor 92 and light source device 95 . The insertion portion 60 has a hard member 60A1 made of stainless steel or the like at the distal end portion 60A. Hard member 60A1 has through holes H10, H63, and H65.

An endoscope illumination optical system (hereinafter also referred to as "optical system") 10 is inserted into the through hole H10. The optical system 10 includes a fiber bundle 20 including a plurality of optical fibers 21 and a resin 40, a base 30, and an illumination optical system (hereinafter also referred to as "optical system") 50.

The through hole H63 is inserted with a channel tube 63 into which a treatment instrument or the like is inserted from the operating portion. An imaging device 65 is inserted into the through hole H65.

The fiber bundle 20 of the optical system 10 , the cable 66 connected to the imaging device 65 , and the channel tube 63 pass through the insertion section 60 . The outer peripheral surface of the insertion portion 60 is covered with resin 64 .

The light generated by the light source device 95 is guided to the tip portion 60A via the fiber bundle 20 and emitted toward the subject. Illumination light is reflected on the surface of the subject, and the reflected light is converted into an imaging signal by the imaging device 65 . The imaging signal is transmitted to processor 92 via cable 66 . The imaging signal is processed by the processor 92 and an endoscopic image is displayed on the monitor 93 . Note that the imaging signal may be converted into an optical signal and guided through an optical fiber.

As will be described later, the optical system 10 has high reliability and heat generation is suppressed, so the endoscope 9 has high reliability and heat generation is suppressed.

<First embodiment>
As shown in FIG. 2, the optical system 50 of the endoscope illumination optical system 10 of this embodiment includes three convex lenses 51, 52, 53 and a lens frame 54 that holds the lens 51 and the like. All of the optical surfaces of the convex lenses 51, 52 and 53, except for the exit surface 50SA, are coated with an antireflection film. Furthermore, the convex lens 53 has a single-fiber configuration in which a high refractive index glass (core) 53a is covered with a low refractive index glass (cladding) 53b. The light emitted from the optical fiber 21 is efficiently emitted from the convex lens 51 to the illumination field by also utilizing total reflection at the boundary between the core and the clad of the convex lens 53 . A fiber bundle 20 including a plurality of optical fibers 21 is bundled with a base 30 at its distal end. The proximal end surface of the optical system 50 and the distal end surface of the fiber bundle 20 are fixed so as to face each other.

As shown in FIG. 3, the cross section of the optical fiber 21 is circular, and resin 40 is filled between the plurality of optical fibers 21 in the base 30 . The tip portions of the plurality of optical fibers 21 are firmly bonded to each other with resin 40 . Therefore, even if stress is applied to the fiber bundle 20 , the optical fibers 21 are less likely to come off from the base 30 . The optical system 10 is highly reliable with no reduction in the intensity of the illumination light.

3 shows a small number of optical fibers 21 for explanation, the fiber bundle 20 includes 1000 to 4000 optical fibers 21, for example.

For example, the thermal conductivity of the resin 40, which is an epoxy resin, is not high. Therefore, when the light reflected by the distal end surface of the optical fiber 21 or the proximal end surface of the optical system 50 is absorbed by the resin 40, the resin 40 generates heat. In order to suppress the heat generation of the resin 40 , it is effective to improve the filling rate of the plurality of optical fibers 21 in the base 30 and reduce the ratio of the resin 40 in the base 30 .

Assuming that the inner diameter (diameter) of the base 30 is D30, the outer diameter (diameter) of the optical fiber 21 is D21, and the number of optical fibers 21 is N, the cross-sectional area V30 of the resin 40 in the base 30 is given by the following (Equation 1 ).

V30=(D30/2) ² -N(D21/2) ² (Formula 1)

In the optical system 10 of this embodiment, the inner diameter D32 of the base 30 is smaller than the inner diameter D31 of the proximal end. That is, it has a proximal region 31 having a substantially constant inner diameter D31 and a distal region 32 having a substantially constant inner diameter D32 smaller than the inner diameter D31 of the proximal region 31 . The inner diameter D30 of the mouthpiece 30 gradually changes in the boundary region between the proximal end region 31 and the distal end region 32 .

Note that the substantially constant inner diameter D30 means, for example, that the minimum inner diameter and the maximum inner diameter are 98% or more and 102% or less of the average inner diameter D30. A thickness T30 of the mouthpiece 30 is substantially the same between the proximal region 31 and the distal region 32 .

The optical system 10 contains less resin 40 in the tip region 32, which is most likely to generate heat. Therefore, the optical system 10 is suppressed in heat generation. Moreover, since the inner diameter D31 of the base end region 31 is large, the adhesive strength of the bundled optical fibers 21 is high.

The inner diameter D32 of the distal end region 32 is preferably 95% or less of the inner diameter D31 of the proximal end region 31 because the effect is remarkable.

In the method of manufacturing the optical system 10, first, the ends of the bundled optical fibers 21 are inserted into the base 30, which is a hollow cylinder made of metal (for example, aluminum) that is easily plastically deformed. Then, the interfacial tension is used to inject the resin 40 into the gaps between the plurality of optical fibers 21 . A plurality of optical fibers 21 coated with resin 40 may be inserted into base 30 . Alternatively, after the plurality of optical fibers 21 are arranged in the base member having a U-shaped cross section, the opening of the base member may be closed.

As shown in FIG. 4, only the tip region 32 of the mouthpiece 30 is drawn using, for example, a swaging device 39 . After the resin 40 is thermally cured, the tip of the fiber bundle 20 including the spinneret 30 is cut, and the cut surface is polished to produce the fiber bundle 20 fixed by the spinneret 30 .

Since the base end of the base 30 of the optical system 10 is not drawn, the optical fiber 21 is less likely to break during processing and use. In order to prevent damage to the optical fiber 21, the inner diameter D32 is preferably 90% or more of the inner diameter D31. In addition, the inner diameter D30 of the mouthpiece 30 gradually changes in the boundary region. Therefore, the optical fiber 21 is more resistant to breakage. The angle θ (see FIG. 4) formed by the outer peripheral surface of the tip region 32 and the outer peripheral surface of the boundary region is preferably 75 degrees or less, particularly preferably 45 degrees or less.

The optical system 10 is highly reliable because heat generation is suppressed and the intensity of illumination light does not decrease.

<Modified Example of First Embodiment>
Next, endoscope illumination optical systems 10A and 10B of modified examples of the first embodiment will be described. Since the optical systems 10A and 10B are similar to the optical system 10 of the first embodiment, the components having the same functions are given the same reference numerals and their explanations are omitted.

<Modification 1 of the first embodiment>
As shown in FIG. 5, in the modified endoscope illumination optical system 10A, the base 30A has an inner diameter D33 smaller than the inner diameter D31 of the base end region 31 and larger than the inner diameter D32 of the distal end region 32, and It has a substantially constant intermediate region 33 .

The optical system 10A has the same effect as the optical system 10, and furthermore, since the length of the tip region 32 that is most likely to generate heat is short, heat generation is suppressed more than the optical system 10. Since the inner diameter D30 of 30B is changed, the intensity of the illumination light is not lowered and the reliability is high.

The angle formed by the distal region 32 and the intermediate region 33 and the angle formed by the intermediate region 33 and the proximal region 31 are preferably 75 degrees or less, particularly preferably 45 degrees or less.

An optical system 50A of the optical system 10A has one convex lens 55 and a lens frame . That is, the optical system is not limited to the configuration including the three convex lenses 51, 52, 53 shown in FIG. 2 and the like. Note that the optical system 10A may have two or more intermediate regions.

<Modification 2 of the first embodiment>
As shown in FIG. 6, in the modified endoscope illumination optical system 10B, the base 30B has an inner diameter D30 that changes continuously from the distal end 32A toward the proximal end 31A. The inner diameter D32A of the distal end 32A is preferably 95% or less of the inner diameter D31A of the proximal end 31A.

The optical system 10B has the same effects as the optical system 10, furthermore, heat generation is suppressed more than the optical system 10, and furthermore, since the inner diameter D30 of the base 30B changes gently, even if the optical fiber 21 is broken, the illumination will be reduced. High reliability with no reduction in light intensity.

The optical system 50B of the optical system 10B has one concave lens 56 and a lens frame 54. As shown in FIG.

<Second embodiment>
The endoscope illumination optical system 10C of the second embodiment is similar to the endoscope illumination optical system 10, and has the same effects. .

As shown in FIG. 7, in the optical system 10C, an antireflection film 59 is provided on the output surface 50SA of the convex lens 51 at the tip of the optical system 50. As shown in FIG. The antireflection film 59 is a multilayer film in which a plurality of layers each including a plurality of low refractive index layers and a plurality of high refractive index layers are alternately laminated.

As an example of the antireflection film 59, the structures of the antireflection films 59A to 59G are shown below. Note that the first layer is the first layer to be coated on the lens. The refractive index measurement wavelength is 546 nm.

FIG. 8 shows the spectral reflectance of the antireflection films 59A to 59G.

The material of _the low refractive index layer _is preferably _SiO2 , _Al2O3 , _Y2O3 , _LaAlO4 , or a mixture thereof. The material _of the high refractive index layer _{is Al2O3} , _{Y2O3 , ZrO2} , _Ta2O5 , _{TiO2 , HfO2} , _Nb2O5 , _LaTiO3 , _LaAlO4 , or mixtures thereof is preferred. The antireflection film 59 may have two or more types of low refractive index layers, or may have two or more types of high refractive index layers.

The lens 51 and the like are made of, for example, optical glass, quartz, sapphire, stabilized zirconia (YSZ), or yttrium aluminum garnet (YAG). For example, the thickness of each layer deposited by ion-assisted vapor deposition, ion plating, or sputtering is 5 nm or more and 150 nm or less.

When the illumination light is Fresnel-reflected by the emission surface 50SA, the adhesive (not shown) that fixes the optical system 50 to the through hole H10 of the hard member 60A1 absorbs the reflected light and generates heat. Since the optical system 10C is provided with the antireflection film 59 on the exit surface 50SA of the optical system 50, Fresnel reflection on the exit surface 50SA of the illumination light can be reduced. Therefore, the optical system 10</b>C generates less heat than the optical system 10 .

It should be noted that the surface layer of the antireflection film 59 disposed on the outer surface farthest from the lens 51 is preferably a high refractive index layer. This is because the high-refractive-index layer has a higher density than the low-refractive-index layer, and exhibits high resistance to chemical solutions used for cleaning the endoscope 9 or the like. From the viewpoint of chemical resistance, the surface layer preferably has a thickness of 3 nm or more.

In the optical systems 10, 10A to 10C, as shown in FIG. 7, the distance L from the tip of the proximal region 31 to the exit surface 50SA is between 7 and 13 times the inner diameter D32 (D32A) of the tip. Preferably.

If the distance L is equal to or greater than the lower limit, the heat generated by the illumination light reflected at the exit surface 50SA in the optical system 50 is less likely to be transmitted to the fiber bundle 20, and the heat of the fiber bundle 20 is less likely to be transmitted to the optical system 50. . If the thickness is equal to or less than the upper limit, a minimally invasive endoscope can be provided because the distal end portion 60A is short and small.

Needless to say, the endoscopes 9A-9C including the optical systems 10A-10C have the effects of the optical systems 10A-10C. Although the endoscope 9 and the like are for medical use, they may be used for industrial purposes, and the insertion portion 60 may be flexible or rigid. The endoscope 9 or the like may be an endoscope in which the insertion section 90 is integrated with the processor 92, the monitor 93 or the like. Alternatively, the imaging signal may be converted into an optical signal and transmitted through the insertion section 60 .

The present invention is not limited to the above-described embodiments and the like, and various modifications, alterations, and the like are possible without departing from the gist of the present invention.

8 Endoscope system 9, 9A to 9C Endoscope 10, 10A to 10C Illumination optical system for endoscope (optical system)
Reference Signs List 20 Fiber bundle 21 Optical fiber 30 Base 31 Base end region 32 Tip region 33 Intermediate region 39 Swaging device 40 Resin 50 Illumination optical system (optical system)
51, 52, 53, 55, 56... Lens 54... Lens frame 59... Antireflection film

Claims (9)

a fiber bundle composed of a plurality of optical fibers and guiding light;
a base into which the tip portion of the fiber bundle is inserted and which bundles the plurality of optical fibers;
a resin filling spaces between the plurality of optical fibers at the tip;
an illumination optical system for receiving the light emitted from the tip surface of the fiber bundle and emitting the light from an emission surface;
An illumination optical system for an endoscope, wherein the base has an inner diameter smaller at its distal end than at its proximal end. 2. The inner diameter according to claim 1, wherein the mouthpiece has a proximal region having a substantially constant inner diameter and a distal region having a substantially constant inner diameter smaller than the inner diameter of the proximal region. Illumination optical system for scopes. 3. The cap according to claim 2, wherein the mouthpiece has at least one intermediate region having an inner diameter smaller than the inner diameter of the proximal end region and larger than the inner diameter of the distal end region, and having a substantially constant inner diameter. An illumination optical system for an endoscope as described. 2. The illumination optical system for an endoscope according to claim 1, wherein said base has an inner diameter that continuously changes from said distal end toward said proximal end. 5. The endoscope illumination optical system according to claim 1, wherein the inner diameter of the distal end is 95% or less of the inner diameter of the proximal end. 6. The light-emitting surface according to any one of claims 1 to 5, wherein an antireflection film in which a low refractive index layer and a high refractive index layer are alternately laminated is provided on the exit surface. Illumination optical system for endoscopes. 7. The illumination optical system for an endoscope according to claim 6, wherein the antireflection film has the high refractive index layer provided on the outer surface thereof. 4. The illumination optical system for an endoscope according to claim 2, wherein the distance from the tip of the base end region to the exit surface is 7 times or more and 13 times or less of the inner diameter of the tip. system. An endoscope comprising the endoscope illumination optical system according to any one of claims 1 to 8.

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