JPS60101503A - Power laser guide - Google Patents

Abstract

PURPOSE:To obtain a flexible power laser guide high in safety using a plastic sheath by forming a low-m.p. metal layer on an optical fiber core and enabling detection of disconnection of the metal layer due to heat melting caused by leaked laser beams at the time of disconnection of the core. CONSTITUTION:A metal tape 6 made of, e.g., an Sn-Pb alloy or the like having <200 deg.Cm.p. is wound on an optical fiber core 5 or lengthwise attached to said core 5. Further, the tape 6 is covered with a tube made of heat resistant and heat insulating material, such as polytetrafluoroethylene, and besides, the tube 7 is coated with a protective layer 8 made of PE or the like having plural tension- resisting wires 10 made of steel or reinforced plastic fibers buried in it to form a flexible high-output laser beam guide. The low-m.p. metal layer 6 is prepared, e.g., by short-circuiting 11 the ends of a pair of wires made of said metal at one side, bonding them to one side of glass fiber fabric 9 to form the tape 6, and winding it on the core 5. When the core 5 is disconnected, the disconnection of the metal wires 6 due to heat melting caused by leaked laser beams is detected with a detector 13, and it is connected with an on-off switch for operating the power laser device 14 to stop transmission of the laser beams.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a power laser guide that transmits high-power laser light.

(Technical Background of the Invention) As shown in FIG. 1, a conventional power laser guide has a thermoplastic resin, such as polyethylene, on a multi-fiber 2 consisting of kla optical fibers 1 that are twisted or bundled. The sheath layer 3 is provided with a metal pipe 4 on top of the sheath layer 3. The metal pipe 4 is provided to prevent the laser beam from jumping out of the guide when the optical fiber wire 1 is broken.

(Node of Background Art) However, when the metal pipe 4 is used, the flexibility of the power laser guide is significantly reduced, making handling thereof extremely inconvenient. For this reason, conventionally, a corrugated pipe is used as the metal pipe 4, and a core diameter of 80 to 100 μm is used as the fiber 2.
Although a plurality of extremely thin optical fibers with a m1 cladding diameter of 140 to 150 μm are used in a bundle, this alone does not provide sufficient flexibility and there is still a problem in terms of operability.

In order to increase flexibility, it is preferable not to use a metal sheath, but this requires adequate safety measures in case of fiber breakage.

(Object of the invention) The object of the invention is to automatically detect a break in an optical fiber,
Moreover, it is an object of the present invention to provide a highly safe power laser guide having nf flexibility.

(Summary of the invention) The power laser guide of the present invention has a power laser guide on an optical fiber core line.
A low melting point metal wire is provided which is heated by the laser light leaked when the core wire breaks and is fused by the heat. This outer periphery is provided with an insulating plastic tube to prevent heat dissipation so as to retain enough heat to cause the tube to melt.

On top of that, a plastic retention layer is provided to maintain the flexibility of the entire power laser guide. Breakage of the core wire is detected by a detector that detects breakage of the low melting point metal layer.

(Example of the invention) Embodiments of the present invention will be described below with reference to the drawings.

The power laser guide according to the present invention includes an optical fiber core wire 5, as shown in FIG. This optical fiber core wire 5
has a step-index type quartz fiber core, on which a primary coat of silicone resin, etc. is provided, and on top of that, a protective coating of polyamide resin, fluororesin, etc. is applied. .

As the fiber core of this optical fiber core wire 5, for example, a large diameter fiber having a quartz core with a diameter of 1200 μm and a quartz cladding with a wall thickness of 200 μm is used. Then, the thickness of the primary coat and the protective coating layer was each 100 μm.
By forming the core wire 5 to a thickness of about 300 μm, the flexibility of the core wire 5 itself can be maintained. In addition, the fiber core may have a multi-core structure, such as a multi-core fiber in which many cores are embedded in a quartz cladding, or a bundle of fibers coated up to the primary coat.

On the optical fiber core wire 5, a low melting point metal layer 6 such as a metal tape or a wound or longitudinal layer of gold R wire is provided.

This metal preferably has a melting point of about 200° C. or lower, and is preferably an alloy of tin and lead, so-called solder, molded into a wire or tape shape. In addition to this, a polyester tape with an aluminum film deposited on its surface can also be used. This low melting point metal layer 6 is heated and fused by the leaked light when the optical fiber core wire 5 is broken.

A heat insulating plastic tube 7, for example a tetrafluoroethylene tube, is provided on the low melting point metal layer 6. This heat insulating plastic tube 7 is provided to 1) prevent the heat from dissipating outside the power laser guide, and due to its heat insulating effect, the temperature rise rate due to heating of the low melting point metal layer is fast, and it is ensured that To melt.

As a composite of the heat insulating plastic tube 1 and the low melting point metal layer 6, for example, as shown in FIG. 3, a glass fiber woven fabric 9 with a lead-tin alloy 10 attached to one side may be used. This is wrapped around the optical fiber core 5 as shown in FIG.

A plastic preservation layer 8, for example a polyethylene coating layer, is further provided on the heat insulating plastic tube 7. A plurality of tensile strength wires 10 made of steel or reinforced plastic are embedded in this polyethylene coating.

This plastic layer 8 is provided to reinforce the entire power laser guide and protect it from external damage, and its thickness and material are appropriately selected as required.

FIG. 4 is a wiring diagram of a system for detecting a break in a fiber core.

Two low melting point metal wires 6 are wound in pairs on the optical fiber core wire 5, one end 11 of which is short-circuited as shown.

The other end 12 of the low melting point metal wire 6 is connected to an input terminal of a detector 13. An ON-OFF switch for operating the power laser device 14 that inputs a laser beam into the optical fiber core wire 5 is connected to the detector 13 .

When the operation switch of the power laser device 14 is turned on and the laser beam is input to the optical fiber core wire 5 of the power laser guide, if the optical fiber core wire breaks for some reason, the laser light will be emitted at the broken point of the optical fiber core wire 5. The low melting point metal layer 6 is irradiated in whole or in part, and in some cases, the insulating tube (not shown) is irradiated mostly. When tetrachlorethylene is used for insulation tubes,
This has a heat resistance temperature of 270° C. and effectively prevents the heat generated by laser light irradiation from escaping outside the power laser guide. The heat generated within this guide is confined by the heat insulating tube, and this guide rises to the melting temperature of the low melting point metal layer 6. The detector 13 detects the melting and outputs a stop signal to the operation switch of the power laser device 14.
Turn the operation switch OFF. As a result, the power laser device 14 stops its operation. In this way, fires and burns caused by laser light can be prevented.

Note that the power laser device 14 may be set to 0FIi' manually by sounding an official gazette using the detection output of the detector 13.

(Effects of the Invention) As explained above, the power laser guide of the present invention has the following features:
There is no need to use metal sheaths ζ′, ゛ with high M properties,
It has excellent flexibility and is easy to handle.

Further, even if the optical fiber core wire is broken 117i, a warning is immediately issued or the transmission of the laser beam can be stopped, so that fires and burns can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional power laser guide, FIG. 2 is a cross-sectional view of an embodiment of the power laser guide of the present invention, and FIG.
The figure shows a cross-sectional view of an example of a tape that combines a low-melting point metal layer and a heat insulating tape, Figure 4 is a longitudinal cross-sectional view of the tape wound around an optical fiber core, and Figure 5 shows a system for detecting breaks in the fiber core. It is a wiring diagram. 5 ------------1 Optical fiber core wire 6 -----
-------One low melting point metal layer 7 ------ One heat insulation chip: L-bu 8, --- One --- Plastic retention layer 13 ------ one detector

Claims (1)

[Claims] An optical fiber core wire into which laser light from a power laser device is input, a low melting point metal layer wound or longitudinally attached on the optical fiber core wire, and a heat insulating plastic tube provided on the low melting point metal layer. and a detector connected to the low melting point metal layer and detecting that the optical fiber core wire is broken and the low melting point metal layer is heated and fused by the laser beam. Features a power laser guide.