JPH0273311A - Manufacture of energy guide - Google Patents

Abstract

PURPOSE:To obtain the energy guide for intermediate infrared rays, whose output power is not fluctuated by a bending state by forming spirally a copper wire, forming a gold plating layer on its surface, and thereafter, eliminating copper of the inside by thick nitric acid, and forming a hollow waveguide made of gold. CONSTITUTION:In order to make a spiral thin gold tube, a copper wire is formed spirally and the surface of copper is plated by gold, and also, by immersing it in thick nitric acid, copper of the inside is smelted and eliminated. As a result, gold of a shell is left, and a hollow waveguide of gold can be formed. Accordingly, since the hollow waveguide is spiral shape from the beginning, there is no optical component which passes through by only traveling straight, even the component which goes into any direction advances in the waveguide, while being brought to multipath reflection. In such a way, even if the waveguide is bent, a loss does not increase newly, that is, the energy guide which is excellent in a characteristic against bending, and whose emitted optical power is stable can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (g) Technical Field The present invention relates to a method for manufacturing an energy guide suitable for transporting carbon dioxide gas (Co2) laser light or -carbon oxide gas (CO) laser light.

Silica-based glass fibers are used for power transmission of visible and near-infrared laser light.

However, quartz fibers cannot be used for laser beams in the mid-infrared region such as CO2 lasers and CO lasers. This is because the loss is large.

Co2 lasers are widely used for industrial processing and medical purposes because they can easily obtain high-output energy.

Transmission systems for guiding CO□ laser light have been proposed and used: (1) mirror joint type, (2) optical fiber type, and (3) hollow waveguide type.

The mirror joint type is bulky and the movement at the joint is complicated. Lack of flexibility.

The optical fiber type is one in which a laser beam is passed through a silver halide crystalline fiber, a thallium halide crystalline fiber, or an alkali halide crystalline fiber. These materials have relatively low absorption of infrared light. Furthermore, since the diameter can be made to be 1ffJIφ or less, it is highly flexible and pliable. However, since the fiber is strongly heated by laser light, it is difficult to pass high-power laser light through it.

A hollow waveguide allows propagation in air surrounded by metal. Since the medium is air, there is little transmission loss.

However, since the light hits a wall in the waveguide and is reflected, there is a reflection loss.

The walls of the waveguide are made of metal to reduce reflections.

Various hollow waveguides have been proposed, depending on the type of metal and shape.

(a) Prior art Hashishin, Kubo et al. have created a hollow waveguide for C02 laser light using a tape-shaped aluminum foil (width 4H to 8H) supported at both ends with Teflon spacers and surrounded by a heat shrinkable tube on the outside. We are making a prototype.

The cross section of the waveguide is flat, 0.5xgx4+w or o,5
This is Hx8 Tomo. There is sufficient flexibility in the direction of the short sides.

The reflective surface is aluminum. Hashi Arata, Kubo “High output power of CO2 laser beam flexible transmission line” Laser Society Research Group Report, R
TM-85-24 (1985) V-1° Fig. 3 shows a sectional view of this energy guide.

The present inventor has proposed a water-cooled energy guide in which molybdenum MO is processed into a tube shape and cooling water is passed around the outer periphery of the tube (filed in U.S. Pat. No. 63-4558, S63.1.18). A schematic sectional view of this is shown in FIG.

(O) Problems to be Solved by the Invention Since it is an energy guide, it must be able to efficiently transmit light such as a CO2 laser or a CO laser. It is also strongly desired that the guide be flexible and easy to bend.

Furthermore, it is desirable that the output power does not vary depending on the bending state. Otherwise, vibrations of the energy guide will change the intensity of the output power. It becomes impossible to process with constant power.

Changing the bending state changes the number of multiple reflections and the reflection angle within the waveguide.

In order for the output power to remain unchanged despite this, the metal used for the reflective surface must have an extremely high reflectance.

The hollow waveguide using aluminum foil described above bends in the short side direction, but not in the long side direction. There is a problem with flexibility.

This also has the disadvantage that the output power varies significantly depending on the bending state. In the case of a hollow waveguide with a long side of 8H, if the bending radius is 8a or less, the output power will be 50% or less compared to a straight waveguide.

It is difficult to process a thin M when using a pipe. This is because MO is hard and brittle. Additionally, MO pipes have difficulty in flexibility. It is not possible to bend it freely. If you bend it forcibly, it will break.

00 OBJECTIVES It is an object of the present invention to provide a method for manufacturing an energy guide for mid-infrared light that is highly flexible, has low transmission loss, and whose output power does not vary depending on the bending state.

(a) Method of the present invention The purpose of the present invention is to produce a thin spiral gold tube.

For this purpose, the copper wire is formed into a spiral shape, and the surface of the copper is coated with gold (Au).
is plated, and then soaked in concentrated nitric acid to dissolve and remove the copper inside. When you do this, the outer shell will be golden. This is a spiral from the beginning. It is not a process of turning a straight pipe into a spiral.

The copper wire becomes the core, but is later removed. The dimensions of the copper wire define the inner diameter of the waveguide. The diameter of copper is, for example, 0.3Hφ~
It is approximately 2111φ.

The copper wire is wound into a spiral, and the pitch and diameter of the spiral may be appropriately determined depending on the purpose.

The gold plated around the copper wire must have a certain thickness. This is because the shape must be maintained only by the gold layer. Therefore, the thickness must be 50 μm or more.

A thick gold plating layer results in poor flexibility and wastes money. Therefore, the thickness of the gold plating layer is set to 0.5 ff or less.

The purpose of soaking in concentrated nitric acid is to dissolve only the copper inside. If the outer diameter of the copper wire is large, concentrated nitric acid can easily enter the wire, so copper can be removed more quickly.

After completely removing the copper inside, thoroughly wash and dry.

In this way, a spiral gold tube hollow waveguide is obtained. 1st
The figure schematically illustrates this process.

Infrared laser light is incident on one end of this gold tube hollow waveguide and emitted from the other end. This is shown in Figure 2.

It can be used as is, but if the laser power is high, the entire spiral gold tube should be water-cooled to prevent damage from heating.

ψ) Example (1) A copper wire having a diameter of INMφ and a length of 5 m was wound around a cylindrical object having a diameter of 40H and processed into a spiral shape.

(2) The thickness of the spiral copper wire is approximately 1 mm by electroplating.
A gold plating layer of 00 μm was formed.

(3) The whole was immersed in a large amount of concentrated nitric acid all day and night. The copper in the center was then completely removed.

(4) The whole was thoroughly washed and completely dried.

(5) Optical systems were attached to both ends, and the transmission characteristics for CO□ laser light were measured.

(6) When the incident light power of the Co□ laser was 200 W, the laser power that passed through the spiral waveguide was 150 W. It can be seen that the loss associated with passage is small.

(7) We also investigated the bending characteristics of the waveguide.

The output end was bent left and right to measure changes in output power.

Even when the output end was bent by up to ±60°, the output light power did not fluctuate. It turns out that this method is extremely effective against waveguide bending.

(g) Effects (1) It is a hollow waveguide with a spiral shape from the beginning. There is no light component that passes through the waveguide as it only travels in a straight line, and components that enter in any direction are subject to multiple reflections as they travel through the waveguide.

For this reason, even if the waveguide is bent, no new loss increases. That is, it has excellent bending properties.

Even if the waveguide vibrates, the output light power remains stable.

(2) Instead of making straight gold tubes by extrusion molding, a spiral shape is made by plating gold on copper. When attempting to form a straight pipe into a spiral, non-uniform distortion occurs, the spiral does not form properly, and part of the waveguide is blocked or broken.

However, when plating was done on copper, which was spiral from the beginning,
Create a golden spiral. No mechanical stress or distortion remains after copper is removed.

(3) The difference in chemical properties of copper and gold towards concentrated nitric acid is skillfully utilized. All copper can be removed, but gold is not wasted.

(4) The gold that remains as the outer shell has an extremely high reflectance to infrared light. Therefore, the reflection loss is lower than that of aluminum or molybdenum hollow waveguides.

(5) The gold that remains as the outer shell is highly ductile and malleable. Since it is a flexible material, even if the waveguide is repeatedly bent, there is little fatigue.

[Brief explanation of the drawing]

FIG. 1 is a process diagram of the energy guide manufacturing method of the present invention. FIG. 2 is a schematic diagram of an optical system for inputting infrared laser light and measuring output light. Figure 3 is a cross-sectional view of a flat hollow waveguide using aluminum foil. FIG. 4 is a sectional view of the energy guide of Utility Application No. 63-4558 filed by the present inventor. Inventor Hirokuni Namba

Claims (1)

[Claims] In order to manufacture an energy guide for transmitting infrared laser light, copper wire is formed into a spiral shape, a gold plating layer is formed on the surface of the wire, and the copper inside is removed using concentrated nitric acid to create a gold-plated material. An energy guide manufacturing method characterized by forming a hollow waveguide.