JP2851132B2 - Endoscope light guide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention is provided in an endoscope for observing the inside of a body cavity of a living body, and transmits illumination light generated from a light source. The present invention relates to a light guide for an endoscope for sending to an examination site in a body cavity.

(Prior Art) This type of endoscope light guide includes a plurality of optical fiber bundles bundled and provided in a guide tube of the endoscope. During observation in the body cavity, a guiding tube is introduced into the body cavity,
Illumination light generated from a light source provided outside the body cavity transmits the light guide in the guiding tube, and irradiates an inspection site in the body cavity from the leading end of the guiding tube.

As shown in FIG. 6, a plurality of optical fiber strands are provided at the light incident end face of the light guide where the illumination light is incident.
101 are bundled and adhered by an adhesive 102 made of resin. The bundle of these optical fibers 101 is fixedly arranged at a high filling rate in the tubular storage member 103.

(Problems to be Solved by the Invention) However, in the case of the above-described conventional technology, the adhesive 10
Since almost no light is transmitted, when the illumination light is incident on the light incident end face of the light guide, the illumination light is incident only on the optical fiber 101 and not on the adhesive 102 portion.
Therefore, there is a problem that the incidence efficiency of the illumination light in the light guide is poor. And it is necessary to increase the number of the optical fiber wires 101 in order to obtain the required illumination light amount,
This hinders the reduction in the diameter of the light guide and, in turn, the reduction in the diameter of the guiding tube.

In order to solve the problem as in the prior art, a method has been devised in which a plurality of optical fiber wires at the light incident side end are fused and integrated with glass having excellent light transmittance. Since the light incident side end face portion is almost 100% light transmitting portion, the illumination light incident efficiency of the light guide is improved, but a special technique for glass fusion is required, and there is a disadvantage that the manufacturing cost is increased. .

The present invention has been made in order to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a light guide for an endoscope which can be easily manufactured and has a high incidence efficiency of illumination light. Is to do.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, according to the present invention, a plurality of optical fiber strands are bundled to illuminate an inspection site in a body cavity. In the light guide for an endoscope transmitting the illumination light, the light incident end face portion on which the illumination light is incident is formed by bonding the plurality of optical fiber wires with a light transmission type adhesive, and the refractive index of the adhesive Is smaller than the refractive index of the cladding of the optical fiber.

(Operation) In the light guide for an endoscope of the present invention having the above-described configuration, a light transmitting adhesive having excellent light transmittance is used, so that only the optical fiber is used at the light incident end face. But also on the adhesive. That is, the light incident end face of the light guide becomes almost 100% light transmitting portion, and the illumination light is incident on the light incident end face with high efficiency. Furthermore, most of the illumination light incident on the adhesive is incident on the cladding of the optical fiber, since most of the refractive index of the adhesive is smaller than the refractive index of the cladding of the optical fiber. Light enters the core from the cladding of the wire. That is, the adhesive portion serves as a second clad of the optical fiber. Therefore, the illumination light is incident on the optical fiber with high efficiency, and this light guide achieves high illumination light incidence efficiency.

In addition, the light incident end face of this light guide can be formed simply by bonding the optical fiber with an adhesive, so that special techniques such as glass fusion are not required, and the light guide can be easily manufactured at low cost. Guides can be manufactured.

(Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a light incident side end of an endoscope light guide according to an embodiment of the present invention. 2 is an end view showing a light incident end face of the light guide, and FIG. 3 is a perspective view showing an endoscope provided with the light guide.

In FIG. 3, the endoscope 1 is connected to the operation tube 3 for guiding a scope into the body cavity, an operation unit 3 provided at the base end of the tube 2 for performing a scope operation, and the operation unit 3. Universal code 4. The universal cord 4 is connected to the device main body 5 of the electronic endoscope device,
Processes signals transmitted from an unillustrated light source that generates illuminating light for illuminating an examination site in a body cavity, and an unillustrated imaging device such as a CCD provided in the distal end of the guiding tube 2. An information processing unit for performing the operation. The image sensor converts the light image formed by the illumination reflected light from the inspection site into an electric signal and sends it to the information processing unit.The information processing unit subjects the signal to signal processing and display processing to convert the image signal into a CRT image signal. The image is sent to the monitor 6 such as a display, and the surface state of the inspection part is displayed on the screen of the monitor 6 as an image.

A light guide (described later) for transmitting illumination light generated from the light source is provided in the guide tube 2, the operation unit 3, and the universal cord 4 of the endoscope. It is sent to the distal end of the guiding tube 2 via the light guide, and irradiates an inspection site in a body cavity from an illumination window formed on the distal end surface of the guiding tube 2. As shown in FIG. 1, this light guide is formed by bundling a plurality of optical fiber strands 7, and a light incident end face portion 8 on which the light generated by the light source is incident is formed by the optical fiber strands 7 transmitting light. It is bonded by a light transmitting adhesive 9 having excellent properties.

That is, the plurality of optical fibers 7 at the light incident side end 10
Are adhered by an adhesive 9 and fixedly arranged at a high filling rate in a base 11 as a tubular metal housing member. The adhesive 9 has a refractive index smaller than that of a clad 7a of the optical fiber 7 described later. In FIG. 1, reference numeral 12 denotes a flexible portion to which the optical fiber 7 is not bonded. FIG. 2 is an end view showing the light incident end face portion 8.

As shown in FIGS. 4 (a) and 4 (b), the optical fiber 7 has a tubular clad 7a filled with a core 7b having a higher refractive index than the clad 7a. Therefore, as shown by the arrow in FIG. 3A, light that has entered the cladding 7a and has reached the boundary surface between the core 7b and the cladding 7a enters the core 7b, while it has entered the core 7b and has entered the boundary. Light reaching the surface is reflected into the core 7b. In addition, since the refractive index of the adhesive 9 is smaller than that of the clad 7a, most of the light incident on the adhesive 9 at the light incident end face portion 8, as shown by the arrow in FIG. It reaches the interface with clad 7a and clad 7a
Incident inside.

That is, since the adhesive 9 is a light-transmitting adhesive that transmits most of the light, the illumination light generated from the light source is incident on almost the entire light incident end face 8 of the light guide. Most of the illuminated light enters the cladding 7a of the optical fiber and further enters the core 7b. Therefore, the illumination light is highly efficient and the light guide optical fiber 7
Will be incident. As a result, it is possible to reduce the size of the light source or to reduce the number of the optical fiber wires 7 so as to reduce the diameter of the light guide and, consequently, the diameter of the guiding tube 2. In addition, the light guide can form the light incident end face portion 8 only by bonding the optical fiber 7 with the adhesive 9, so that a special technique such as glass fusion is not required, and the cost is low. It can be easily manufactured.

Further, the light guide is provided from the inside of the universal cord 4 to the inside of the operation unit 3,
The light guide provided from inside the operation section 3 to the inside of the guide tube 2 may be divided into two parts, and the ends of these two light guides may be connected in the operation section 3. Also in this case, both end faces of the connecting portion are connected to the light incident end face 8.
Similarly to the above, the optical fiber is formed by bonding the optical fiber with a light transmission type adhesive. The two light guides are connected with their both end faces facing each other.

As in the case of the light incident end face 8, the illumination light is incident on the light incident end face of the connecting portion with high efficiency, so that light loss can be reduced. Also, in this case, since almost all of the end faces are the light transmitting portions, there is no need to join the optical fibers when connecting the end faces, and the alignment is simple. If the light guide is divided in this way, after the universal cord 4 and the middle guide tube 2 are separately manufactured, the light guide on the universal cord 4 side and the middle guide tube 2 side are combined in the operation unit 3. Since the endoscope 1 can be connected, the endoscope 1 can be easily assembled.

In the above embodiment, the light guide of the electronic endoscope apparatus has been described as an example. However, the present invention is not limited to this, and can be applied to, for example, a light guide of a fiberscope. In addition, the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made.

[Effect of the Invention] The light guide for an endoscope of the present invention has the above configuration and operation, and can be easily manufactured at low cost.
In addition, the incident efficiency of the illumination light can be increased. Thereby, it is easy to reduce the diameter of the light guide, and consequently, to reduce the diameter of the guide tube of the endoscope and to divide the light guide.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a light incident side end of an endoscope light guide according to an embodiment of the present invention, FIG. 2 is an end view showing a light incident end face of the light guide, and FIG. 4A and 4B are perspective views showing an endoscope provided with the light guide.
FIG. 5 is a view showing an optical fiber strand of the light guide, FIG. 5 is a cross-sectional view for explaining the incidence of illumination light on the light guide, and FIG. 6 is a light incident end face of a conventional endoscope light guide. It is an end elevation which shows a part. DESCRIPTION OF SYMBOLS 1 ... Endoscope, 2 ... Guide tube 7 ... Optical fiber wire, 7a ... Cladding 7b ... Core, 8 ... Light incident end face 9 ... Adhesive

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-53-5645 (JP, A) JP-A-62-80612 (JP, A) JP-A-61-198902 (JP, U) 40335 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) A61B 1/00-1/06

Claims (1)

(57) [Claims] A plurality of optical fiber wires bundled together;
In an endoscope light guide for transmitting illumination light for illuminating an examination site in a body cavity, a light incident end face on which the illumination light is incident is bonded to the plurality of optical fiber wires with a light transmitting adhesive. The light guide for an endoscope, wherein the refractive index of the adhesive is smaller than the refractive index of the clad of the optical fiber.