JPH09166754A - Endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the power consumption and to make a device compact by interposing a specified taper fiber between a lamp and the base end of a light guide and making the lamp a low exit angle and high illuminance. SOLUTION: A commercial power source, a lithium battery and a nickel- cadmium battery, etc., are used for a power source 1 and a xenon compact lamp with a front lens, a metal halide lamp and a halogen lamp, etc., are used for a lamp 2. Especially, the lamp 2 has a low exit angle and high luminance. A taper fiber 4 gradually reducing its diameter to the side of tip is interposed between the lamp 2 and the base end face 3a of a light guide 3. The taper fiber 4 is made by extending (while heating) the base material of multiple component glass fiber and its intrinsic numerical aperture NAo , is made to be >=0.4. By using such a taper fiber 4, about 5-10% of the total light emitting amount of the lamp 2 is sent to the light guide and the coupling efficiency is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device used for a medical endoscope having a light guide, an industrial fiberscope, or the like.

[0002]

2. Description of the Related Art For example, as a light source device for an endoscope, a lamp having a power of 100 W or more has been used, and a weight of 1 kg or more has been large. The reason for this is that the coupling efficiency with the light guide base end (incident end) of the endoscope ──the ratio of the amount of light that is effectively incident on the light guide (percentage) within the total number of luminous fluxes of the lamp ── This is because the efficiency was extremely low at 1% or less.

[0003]

Therefore, the conventional light source device is housed in a casing separate from the endoscope body and connected to the endoscope body by a cord having a light guide. Therefore, it is inconvenient to move and carry and consumes a lot of electricity. Needless to say, there is a problem that the industrial fiberscope is inconvenient to move and carry.

[0004]

In a light source device according to the present invention, a tapered fiber gradually decreasing in diameter toward the light end side is interposed between a lamp and a light guide base end face, and the lamp is mounted. It is a high brightness lamp with a low emission angle.

Further, the outer diameter of the incident end of the tapered fiber is D
₁ , the entrance numerical aperture of the tapered fiber is NA ₁ , the outer diameter of the exit end of the tapered fiber is D ₂ , the exit numerical aperture of the tapered fiber is NA ₂ , the outer diameter of the light guide is D ₀ , and between the core and the cladding. When the numerical aperture peculiar to the tapered fiber determined by the refractive index is NA ₀ ,

(Equation 1)

(Equation 2)

## EQU00003 ## The equations (1), (2) and (3) above are set to be satisfied.

Further, the tapered fiber is made of a multi-component glass fiber preform, and the numerical aperture NA ₀ peculiar to the tapered fiber is set to 0.4 or more.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings.

In FIG. 1 and FIG. 4, reference numeral 1 is a power source, a commercial power source, or a lithium battery, a nickel cadmium battery, a primary / secondary battery is used, and 2 is a lamp with a front lens. Xenon compact lamps, metal halide lamps, halogen lamps, etc. are used.

Particularly, the lamp 2 is a high-intensity lamp having a low emission angle. That is, as shown in FIG. 2, the ratio of the light components with the exit angle 2θ ₁ of the lamp 2 of 20 ° or less is 1 of the total front light amount.
/ 2 or more is called "a high-intensity lamp with a low emission angle".

Reference numeral 3 denotes a light guide, and a taper fiber 4 having a reduced diameter is inserted between the light guide 3 and the base end face 3a thereof so as to gradually move toward the tip side. This taper fiber 4
Is made by drawing (heating) a multi-component glass fiber preform, and the numerical aperture NA ₀ peculiar to the taper fiber is 0.4 or more. That is, NA ₀ ≧ 0.4.

In FIG. 1, reference numeral 5 is a part of the light guide plug, and the taper fiber 4 is inserted into the proximal end side hole of the shaft hole 6 and fixed by an adhesive or the like. The emission end 4b is inserted into the intermediate small-diameter portion of the shaft hole 6. On the other hand, 7 is a light guide cover, and the base end of the light guide 3 which projects slightly exposed from the tip thereof is inserted into this intermediate small-diameter portion and abutted against the emission end 4b of the tapered fiber 4. Contact or face each other with a minute gap.

2 and 3 are enlarged and simplified explanatory views of the main parts of FIG. 1 or FIG. 4, and FIGS.
As shown in FIG.
The outer diameter of a is D ₁ , the numerical aperture of its entrance is NA ₁ , the outer diameter of its exit end 4b is D ₂ , the numerical aperture of its exit is NA ₂ , the outer diameter of the light guide 3 is D ₀ , and (As mentioned above)
When the specific numerical aperture of the tapered fiber 4 is NA ₀ ,
The dimensions and characteristics of each part are set so as to satisfy the following formulas 1, 2, and 3.

[0013]

(Equation 1)

[0014]

(Equation 2)

[0015]

(Equation 3)

In the above formula 1, if the value is less than 0.9, the output end 4b of the taper fiber 4 becomes (the light guide base end face 3
The diameter is too small (compared to the diameter of a), and many portions of the cross section of the light guide 3 are not effectively utilized. vice versa,
If it exceeds 1.5, a large amount of waste occurs in the amount of light emitted from the emission end 4b of the taper fiber 4 (it is not effectively transmitted to the light guide 3).

Further, in the equation (2), if it is less than 0.7, the optical density increasing ability of the taper fiber 4 is not used up effectively, and there is a problem in terms of the effect. The amount of light energy leaking out on the way becomes large and there is a problem such as heat generation. Further, when the formula 3 is not satisfied, there is a problem such as heat generation as in the formula 2.

(In FIGS. 1 and 2), the light source device 8 is composed of the power source 1, the lamp 2 and the taper fiber 4 as described above. FIG. 4 exemplifies an endoscope using such a light source device 8. In this medical endoscope, an operating grip portion 9 and an appropriate flexibility and rigidity extending from the tip thereof are provided. And a small-diameter insertion part (10) provided with, and the insertion part (10) is capable of bending like a solid line and an imaginary line.
It has.

A swing operation ring 12 is attached in the middle of the grip portion 9, and the tip swing portion 11 is curved or straightened in association with the reciprocating movement. An image guide plug 13 and a cleaning liquid plug 14 are provided at the base end of the grip portion 9, and the light guide 3 connected to the light source device 8 is branched from the tip of the grip portion 9. . In FIG. 4, the light source device 8 is used separately from the endoscope main body and placed in another place.

On the other hand, in another specific example shown in FIG.
The light source device 8 is attached integrally to the grip portion 9 so as to be portable (movable). The base end of the grip part 9 is an eyepiece part 15 for direct eye contact, and a swinging operation part 16 for bending the tip swinging part (see FIG. 4) (not shown).
Is a reel 18 that winds the swinging wire 17 as a rotary type.
To rotate.

Then, the base end of the light guide is inserted into the branch portion 9a protruding from the base end (or the middle portion) of the grip portion 9 by bending about 90 °, and the tapered fiber 4 is held. Then, the casing 20 (for battery / lamp) containing the battery 1a and the lamp 2 is detachably attached via the cap nut 19.

As described above, the battery 1a is used as the power source 1, and the lithium battery is desirable in that it has a long life, is lightweight and compact, and that the output voltage and current are stable. Further, the lamp 2 is a high-intensity lamp with a low emission angle, and for example, a halogen lamp with a front lens having a power of about 1 watt to 10 watts is suitable. Thus, FIG.
In this case, a cordless endoscope is constructed to facilitate movement and transportation, expand the activity and use range of the operator, and be used for diagnosis and treatment.

The taper fiber 4 used in FIG.
For downsizing, for example, in FIG. 3, D ₁ = 3.6 mm, D
₂ = 1.28 mm, length L is preferably 30 mm to 50 mm, etc. It should be noted that the taper fiber 4 may be arranged on the side of the detachable casing 20 (in place of FIG. 5) (not shown). That is, in the branch portion 9a protruding from the grip portion 9,
On the other hand, the casing 20 holding the base end portion of the light guide and containing the battery 1a, the lamp 2 and the taper fiber 4 via the cap nut 19 is made detachable, and the casing 9 is provided with the branch portion 9a.
In addition, the structure to be attached is also free. It is also preferable to use the light source device of the present invention in an industrial fiberscope.

[0024]

According to the present invention, the following significant effects can be obtained by the above-described structure.

By using the taper fiber 4, approximately 5% to 10% of the total luminous flux of the lamp 2 can be sent to the light guide 3, and the coupling efficiency can be remarkably improved. Therefore, as the light source device, it is possible to reduce power consumption and achieve compactness. This makes it possible to realize a portable endoscope and a portable (industrial) optical fiber scope. The light of the light source lamp can be transmitted particularly effectively (according to claim 2 or claim 3) to the light guide.

[Brief description of the drawings]

FIG. 1 is an enlarged explanatory view of a main part according to an embodiment of the present invention.

FIG. 2 is a schematic explanatory diagram of the present invention.

FIG. 3 is an explanatory diagram of a tapered fiber.

FIG. 4 is an explanatory diagram showing an application example of the present invention.

FIG. 5 is a partially broken essential part explanatory view showing another application example of the present invention.

[Explanation of symbols]

 2 lamp 3 light guide 3a base end surface 4 taper fiber 4a entrance end 4b exit end 8 light source device

Claims (3)

[Claims] 1. Between the lamp and the light guide base end surface,
A light source device characterized in that a taper fiber having a reduced diameter is interposed gradually toward the light end side, and the lamp is a high-intensity lamp with a low emission angle. 2. The outer diameter of the entrance end of the tapered fiber is D ₁ ,
NA ₁ for the incident numerical aperture of the tapered fiber, D _{2 for} the outer diameter of the outgoing end of the tapered fiber, NA ₂ for the numerical aperture of the tapered fiber for the outgoing, the outer diameter of the light guide D ₀ , and the refractive index between the core and the clad. The light source device according to claim 1, wherein when the numerical aperture peculiar to the taper fiber, which is more defined, is NA ₀ , the following numerical formulas 1, 2, and 3 are set. [Equation 1] (Equation 2) (Equation 3) 3. The taper fiber is made of a multi-component glass fiber preform and has a numerical aperture NA specific to the taper fiber.
The light source device according to claim 2, wherein ₀ is 0.4 or more.