JPH0778565B2 - Fiber optic probe - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical fiber probe of a laser irradiation device that guides a laser beam to a target site and is used for treatment of a human body and the like.

2. Description of the Related Art In recent years, an optical fiber probe with excellent operability has been used to guide a laser beam in a laser scalpel or a laser processing machine, and an optical fiber probe with a small diameter and excellent flexibility is used for an endoscope or a hard disk. It has been noticed that a tissue is inserted into a body using a mirror and the affected tissue is treated without opening. A for the CO ₂ laser light as its optical fiber
Materials such as gCl, AgBr, etc., and quartz-based materials are being used for YAG laser light.

When inserting the optical fiber probe into the body, if there is no cover on the emission end side, body fluid will adhere to the end face of the optical fiber and burn out.Therefore, the conventional optical fiber probe has a window fixed to pass the laser beam and protect the end face. ing. However, the optical fiber incorporated in the probe is often burned due to the high energy of laser light. Most of the burned-out points are near the emission end face of the optical fiber. The main reason for this is that the end of the protective tube is heated by the reflected light from the window arranged at the exit end, and is therefore burned.

There is no problem when using the probe with low power laser light of about 1w such as intraocular surgery, but when it is inserted into an endoscope and used, it is often irradiated with high power laser light of 10 to 20w. The suppression of temperature rise at the probe tip has become an important issue.

When the distance between the window and the end face of the optical fiber is separated by about 1 to 4 mm, as shown in FIG. The optical fiber 13 will be burned out by irradiating the optical fiber 13 with the light. In addition, the reflected light from the window 14 is the optical fiber 13
Only a part of the light is absorbed by the end face and the rest becomes reflected light to the surroundings, which also serves as a heat source and burns the optical fiber 13.

If the distance between the window and the end face of the optical fiber is shortened while avoiding the influence of these reflected lights, the laser light passes through the window without the expansion of the emission angle being blocked by the holding member,
Also, most of the reflected light from the window is returned to the optical fiber as return light, and the ratio of laser light irradiating the holding member is reduced, and the temperature rise of the tip portion is reduced. Therefore, the distance between the window and the end face of the optical fiber is 0-0.5m.
It is desirable to set the distance as short as m.

Problems to be Solved by the Invention However, if they are placed too close to each other, the elongation of the optical fiber during laser light transmission becomes a problem.

For example, in the case of a single optical fiber having a diameter of 0.3 mm and a length of 1.5 m, when 10 w of laser light is irradiated, thermal expansion causes expansion of 0.3 to 0.5 mm at the end. That is, even if the distance between the window and the end face of the optical fiber is set to 0.5 mm and the scattered light is avoided, when the high power laser light of 10w to 20w is irradiated, the extended end face of the optical fiber collides with the window and is deformed to be further expanded and burned out. Will be lost. If the window is removed, the temperature rise is very small, but when it is inserted into the body, body fluid adheres to the end face of the optical fiber and burns out.

Means for Solving the Problems The present invention provides an optical fiber that guides laser light, a protective tube that houses and protects the optical fiber, an optical member that covers the exit end of the optical fiber and transmits the laser light, and the optical member is used as the protective tube. A holder for movably holding the optical fiber in the length direction, and a biasing means for constantly biasing the optical member toward the optical fiber output end face are provided in the holder, and the optical member thermally expands the optical fiber. It is characterized by interlocking with.

With the above-described structure, the present invention allows the optical member to be constantly urged toward the exit end face of the optical fiber, so that the distance between the end face and the optical member can always be kept to the shortest, and the optical member is the optical fiber. By following the elongation and moving in the direction of the elongation, the temperature rise of the tip portion is suppressed.

First Embodiment An optical fiber probe according to an embodiment of the present invention is first described.
A description will be given based on FIG. 2 and FIG. An optical fiber 1 made of a material such as AgCl or AgBr is housed in a protective tube 2 made of metal such as SUS or fluororesin. A positioning tool 3 is projected and fixed to one end of the protective tube 2, and the optical fiber 1 is held in a state where the end portion thereof further projects from the positioning tool 3. A window holder 4 has a window 5 made of diamond fixed to one end, and a spring retainer 6 movable to the outside of the protective tube 2 in the length direction thereof is fixed to the other end. The distance between the window 5 and the end face of the optical fiber 1 is 0 to 0.
It is 5 mm. Reference numeral 8 denotes a joint having a wide mouth 8a and a slit 8b, which is fixed to the protective tube 2 and has an open end of a jacket tube 9 made of fluororesin and a base end of a tip probe 10 made of metal or the like. Fixed. Further, in the window holder 4, a pressing spring 7 is interposed between the positioning tool 3 and the spring retainer 6, and the window holder 4 is located outside the protection tube 2 in the axial direction toward the base side. Always urged.

The assist gas 11 flowing between the protective tube 2 and the jacket tube 9 flows from the wide mouth portion 8a of the joint 8 through the slit 8b and between the window holder 4 and the tip probe 10. Erupted.

When the high power laser light of 10 to 20 w is irradiated, the optical fiber 1 is expanded by thermal expansion, and the emitting end further projects from the opening end of the protective tube 2 and comes into contact with the window 5. When the irradiation is continued as it is, the optical fiber 1 contacting the window 5 further extends, and the window holder 4 having the window 5 fixed slides outside the protection tube 2 against the urging force of the pressing spring 7 and interlocks. Follow the growth. When the irradiation of the laser beam is stopped, the extended optical fiber 1 contracts to its original state, and the window holder 4
Also returns to the original position by the pressing spring 6.

With the optical fiber probe using this example, the temperature rise of the tip at 40w input was + 20 ° C. or less, which was an extremely small experimental result.

FIG. 3 shows an optical fiber probe according to another embodiment of the present invention. The positioning tool 12 provided with the wide portion 12a is always in contact with the window 5 of the window holder 4. Other configurations are the same as those in the above-described embodiment, so the same reference numerals are given and description is omitted.

EFFECTS OF THE INVENTION As described above, the present invention keeps the distance between the emitting end and the optical member to be the shortest at all times while the emitting end of the optical fiber is being irradiated with laser light by interlocking the optical member with the elongation of the optical fiber. Therefore, there is no irradiation or heat generation to the optical member holder due to the spread of the emission angle of the laser light as in the case where the optical member and the end face of the optical fiber are greatly separated by about 1 to 4 mm, and There is an excellent effect that burnout of the optical fiber is suppressed without being affected by heat due to reflected light.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional side view of an optical fiber probe in one embodiment of the present invention, FIG. 2 is a side view of a joint in the optical fiber probe, and FIG. 3 is another embodiment of the present invention. FIG. 4 is a vertical side view of the optical fiber probe, and FIG. 4 is a vertical side view of the conventional optical fiber probe. 1 ... Optical fiber, 2 ... Protection tube, 5 ... Window, 7 ... Pressing spring.

Claims (1)

[Claims] 1. An optical fiber for guiding a laser beam, a protective tube for housing and protecting the optical fiber, an optical member for covering the emitting end of the optical fiber and transmitting the laser beam, and the optical member in the protective tube in the optical fiber length direction. A holder for movably holding and a biasing means for constantly biasing the optical member toward the optical fiber output end face are provided in the holder, and the optical member is linked to thermal expansion of the optical fiber. A characteristic optical fiber probe.