JPH02162302A - Hollow light guide body and production thereof - Google Patents

Abstract

PURPOSE:To obtain the hollow light guide having excellent mechanical strength and heat conduction by integrating at least >=2 pieces of hollow pipes with the hollow light guide axially on the outer periphery of the hollow light guide which transmits light energy. CONSTITUTION:Al pipes 3, 4 having respectively 1.5mm outside diameter and 1.1m and 1.05m length are tightly adhered by Al foil 5 and are provided axially on the outer periphery of the Ni hollow light guide 2 which has 1.5mm inside diameter and 1.2m length and contains Ge 1. The apertures at both ends of the Al pipes 3, 4 and the lower apertures of the hollow light guide 2 are hermetically closed by sealing tapes 6. This assembly is immersed in a watt bath 7 kept at 45 deg.C and is energized with an Ni electrode 8 by 4A/dm<2> density for 4 hours to form an Ni plating layer of a sufficient thickness. The sealing tapes 6 are then peeled and the assembly is immersed in a caustic soda to etch away the the Al pipes 3, 4. The hollow light guide integrated with the Ni hollow pipes usable as water cooling pipes on the outer periphery of the hollow light guide 2 made of the Ni contg. the Ge is formed. The hollow light guide having the good mechanical strength and heat conductivity is thereby obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a hollow optical waveguide body for transmitting optical energy and a manufacturing method thereof.

[Prior Art] Conventionally, carbon dioxide gas laser light has been guided to the irradiated el by so-called spatial propagation using many mirrors and lenses. Because of this, in cutting in laser machining, etc., in order to obtain an arbitrary shape, it is necessary to precisely control a complicated optical axis consisting of a mirror lens, and furthermore, it is necessary to control the drive of the workpiece. In order to improve the drawbacks of this spatial propagation method, carbon dioxide laser light transmission using an optical waveguide has been studied.

The carbon dioxide gas laser beam has a wavelength of 10.61 m,
Since it is not possible to transmit using silica-based fibers, the main types of optical waveguides being researched are infrared fiber types using chalcogenide or the like, and hollow guided waveguide types using air as a medium.

Among these, in an infrared fiber using chalcogenide or the like as a solid material, when a laser beam is incident, there is a large amount of reflection at the fiber end face, resulting in intensive heat generation at the input and output portions.

On the other hand, in the case of a hollow optical waveguide with an air core,
There is almost no reflection at the input/output section, making it suitable for high power transmission. In particular, dielectric-incorporated metal hollow optical waveguides are made by coating the inside of a metal pipe with a dielectric to increase the reflectance on the inner wall, and are the most promising as low-loss waveguides.
To date, a prototype nickel hollow optical waveguide with germanium inside has been produced. However, even with a low-loss waveguide, as the incident power increases, the amount of heat due to loss inevitably increases.

Therefore, in order to enable even greater power transmission, a waveguide air-cooled transmission device was invented that takes advantage of the structural features of hollow optical waveguides. This is to flow a cooling gas, such as nitrogen scum, into the hollow region that transmits the carbon dioxide laser beam, and in the case of a germanium-incorporated nickel hollow optical waveguide with an inner diameter of 1.5 mm, the flow rate is approximately 20 Jl/min.
By cooling the nitrogen gas, the transmission capacity increased approximately five times.

[Problems to be Solved by the Invention] However, the maximum power that can be transmitted by air cooling in a hollow optical waveguide is about 300 W in a straight state in the case of a germanium-incorporated nickel hollow optical waveguide with an inner diameter of 1.5 mm, and normally 500w to several kilograms used in laser processing
It cannot be used for W laser beam transmission. In addition, if a hollow optical waveguide is bent and used as a flexible waveguide instead of a space propagation method, the transmission loss at the curved portion increases, the heat generation increases, and the transmission capacity further decreases. Optical waveguides have been impractical in the field of laser processing, which requires high power.

The purpose of the present invention is to solve the problems of the prior art described above,
It is an object of the present invention to provide a hollow optical waveguide body and a method for manufacturing the same, which can extremely efficiently remove heat generated in a hollow optical waveguide during optical energy transmission and dramatically increase maximum transmission power.

[Means for Solving the Problems] The hollow optical waveguide body of the present invention has a structure in which at least two or more hollow tubes are integrated with the hollow optical waveguide in the axial direction on the outer periphery of the hollow optical waveguide that transmits optical energy. belongs to.

In a preferred embodiment, the cooling medium is flowed into a hollow tube integrated on the outer periphery of the hollow optical waveguide, and the openings of the hollow tubes on the optical energy output side of the hollow optical waveguide are interconnected. The medium entrance/exit is formed on the optical energy incident end side of the hollow optical waveguide'! It will be fJ construction.

Furthermore, in the method for manufacturing a hollow optical waveguide body of the present invention, after forming a hollow optical waveguide for transmitting optical energy, at least one conductive hollow tube is axially arranged on the outer periphery of the hollow optical waveguide. A metal film having a thickness sufficient to obtain mechanical strength is formed by electroplating, and then only the conductive hollow tube is removed using a selective etching solution, thereby forming the hollow optical waveguide. A hollow optical waveguide body having a hollow tube integrated on the outer periphery of the optical waveguide body is formed.

In this case, a dielectric-incorporated metal hollow optical waveguide can be used as the hollow optical waveguide, an aluminum pipe can be used as the conductive hollow tube, and a caustic sorter can be used as the etching solution. The inner dielectric may be germanium, the metal layer may be nickel or silver.

[Function] The hollow optical waveguide that transmits optical energy can not only be cooled from the inside by flowing nitrogen scum, etc. inside it, but also by flowing cooling water, etc. into the hollow tube on its outer periphery. The wave channel can be cooled from the outside. Therefore, it is possible to efficiently remove the heat generated in the hollow optical waveguide due to transmission loss, prevent abnormal heat generation, deterioration, and destruction of the hollow optical waveguide, and increase the maximum transmission power, making it possible to transmit power of 500 W or more. becomes.

In addition, by creating a structure in which the openings of the hollow tubes are connected to each other on the light energy output side, the water supply and drainage ports can be provided only on the light energy input side, making the output end completely free, lightweight, and easy to use. The drive can be controlled.

As a hollow optical waveguide for transmitting optical energy, a dielectric-incorporated metal hollow guiding waveguide is the most promising.
e), zinc sulfide (ZnS).

Calcium fluoride (CaF2) or the like is suitable, and for the metal layer, silver, nickel, copper, gold, etc. are suitable.

The above-mentioned hollow optical waveguide body can be easily produced by closely adhering a conductive hollow tube around the hollow optical waveguide, forming a metal film around it by electroplating, and then removing only the conductive hollow tube by etching. can be manufactured. Since they are fixed together by plating, they have excellent mechanical strength and thermal conductivity, and furthermore, because the diameter of the water-cooled tubes that are fixed together can be set arbitrarily, the visibility or linearity of the entire waveguide to be manufactured can be controlled.

Furthermore, since different materials are not used, deformation of the optical waveguide body caused by differences in thermal expansion coefficients and increase in loss caused by stress can be avoided.

[Example] Hereinafter, the present invention will be explained in detail using the drawings.

Example 1 FIG. 1 shows a method of manufacturing a hollow optical waveguide body by electroplating according to the present invention.

First, on the outer periphery of a nickel hollow optical waveguide 2 containing germanium 1 with an inner diameter of 1.5 nm and a length of 1.2 m, a waveguide with an outer diameter of 1.5 nm and a length of 1.1 m is placed in the axial direction.
Aluminum pipes 3 and 4 of 1.05 m are placed in close contact with each other with aluminum foil 5, and the openings at both ends of these aluminum pipes 3 and 4 and the lower opening of the hollow optical waveguide 2 are sealed with seal tape 6.

This assembly is immersed in a Watts bath 7 at a temperature of 45°C, and a current density of 4A/dll12 is applied between the nickel electrode 8 for 4 hours to form a nickel plating layer of sufficient thickness to obtain mechanical strength. Form. After plating, by peeling off the sealing tape 6 and immersing it in caustic soda, only the aluminum pipe 3.4 will be etched and removed, and will be used as a water cooling pipe on the outer periphery of the central germanium-filled nickel hollow waveguide 2. A hollow optical waveguide body integrating a possible nickel hollow tube is formed.

The hollow optical waveguide body manufactured in this manner has excellent mechanical strength and good thermal conductivity because the hollow optical waveguide and the water-cooled tube are made of exactly the same material and are completely integrated. Further, by arbitrarily selecting the diameter of the hollow tube to be integrally fixed, and thus the aluminum pipe 3.4, the flexibility or linearity of the hollow optical waveguide body can be controlled.

Example 2 FIG. 2 shows a nickel hollow optical waveguide 9 with an inner diameter of 1.51 TI around the outer periphery of a germanium-filled nickel hollow optical waveguide 9 with an inner diameter of 1.5 m
FIG. 2 is a diagram of a hollow optical waveguide body 11 according to the present invention, which is configured by integrally fixing six II+ nickel hollow tubes 10.

The central hollow optical waveguide 9 has a thickness of about 0.54 times the thickness of the germanium layer 12, and is made to have the lowest loss for carbon dioxide radar light having a wavelength of 10.6 times.

The outer peripheral hollow tube 10 has a wall thickness of about 200 holes, and the hollow tube 1
Regarding the length of 0, the output end side of the laser beam is formed to be about 610 mm shorter than the output end 13 of the optical waveguide 9.

In addition, on the incident end side of the laser beam, a total of three hollow tubes 10a, every other one of the six hollow tubes 10, are connected to the incident end 1 of the hollow optical waveguide 9.
4, and the other three 10b are formed approximately 30 mm shorter than the incident end 14.

FIG. 3 shows the structure of the laser beam output section when the hollow tube 10 of the present hollow optical waveguide body 11 is used as a water-cooled tube to flow the cooling water 15 and the cooling gas 16 to flow inside the hollow optical waveguide 9. shows.

The exit end side on the left side of the figure is covered with a cap 18 having a folding space 18a, in order to fold back the cooling water flowing through the three hollow tubes 10a and flow into the remaining three tubes 10b, and the cap 18 has a center hole 18b. is fitted into the output end 13 of hollow optical waveguide #19, and sealed with a sealing material 17 made of epoxy resin.

In addition, on the input end side, in order to separate the inflow and outflow of the cooling water 15, sealing material 17 similar to that on the output end side is applied to each of the three hollow tubes for water supply and drainage, and the nozzles 27 and 28 are attached. water supply cap19. The drain caps 20 are provided one after the other in the axial direction. The entrance end 14 portion of the hollow waveguide 9 passes through the water supply cap 19 and the drain cap 20.

A threaded groove 22 is formed on the outside of the water supply cap 19 so that it can be connected to an air cooling holder 24 for air cooling the inside of the hollow waveguide 9.

FIG. 4 shows an example in which the above laser beam emitting section is applied to an optical energy transmission system of a laser processing machine.

In FIG. 4, the carbon dioxide laser beam emitted from the laser oscillator 23 is transmitted to an air-cooled halter 24 equipped with a coupling lens.
Through this, it is coupled to the hollow optical waveguide 9 of a hollow optical waveguide body 25 configured similarly to the hollow optical waveguide body 11 described above. 2 (lj/
Nitrogen sludge of min. min is flowed into the hollow optical waveguide 9 to cool it from inside, and at the same time, from the water cooling nozzle 27 of one water supply cap 1. Cooling water 15 of Ill/mII+ is passed through the hollow tube 10 to cool the hollow optical waveguide 9 from the outside. This transmission system can easily transmit 500W of power.

Example 3 In Example 2, six hollow tubes 10 with an inner diameter of 1.5 mm were integrally fixed around the outer periphery of the hollow optical waveguide 9 with an inner diameter of 1.5+ nm. The wave body is not limited to this.

For example, in the second embodiment, as shown in FIG.
A small deviation of 1.0+nm in the inner diameters of the two hollow tubes that are fixed together can increase the flexibility of the optical waveguide body while maintaining a sufficient water cooling effect. Therefore, conventionally, complicated optical axis control using spatial propagation has not been performed.]2 If this optical waveguide body is used in the field of one-zero cutting, water cooling,
Since the air-cooled refrigerant supply source is concentrated only at the coupling part with the laser beam, it can be easily cut into any shape by controlling the output part of the high-power laser beam with an X-Y plotter, etc. .

Embodiment 4 In addition, in the above-mentioned Embodiment 2, as shown in FIG. 6, a water cooling hollow tube 31 with a large inner diameter of 3 mm was placed around the germanium-incorporated nickel hollow optical waveguide 30 with an inner diameter of 0.8 mm. If they are integrated to form an optical waveguide body, the outer water-cooled hollow tube 30 not only has a cooling effect but also maintains linearity, allowing laser light with high power density and small beam diameter to be transmitted without transmission loss due to bending. It can be emitted without any increase in .

[Effects of the Invention] As described above, according to the present invention, water cooling from the outside of the hollow waveguide for transmitting optical energy becomes possible.
It can transmit power of 500W or more. Moreover, since the water supply and drainage ports can be provided only on the light energy incident side, the output end can be completely free and lightweight, and the drive can be easily controlled. In addition, since it is integrally fixed by plating, it has excellent mechanical strength and thermal conductivity, and furthermore, since the diameter of the integrally fixed water-cooled tube can be set arbitrarily, the flexibility or linearity of the entire waveguide to be manufactured can be controlled. . Since different materials are not used, deformation of the optical waveguide body caused by differences in thermal expansion coefficients can be avoided.
Increased losses caused by stress can also be avoided. That is, according to the present invention, it has become possible to manufacture a hollow optical waveguide equipped with a water cooling mechanism that transmits high-power laser light.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the method for manufacturing a hollow optical waveguide according to the present invention, FIG. 2 is a schematic structural diagram of the hollow optical waveguide according to the present invention, and FIG. 4 is a schematic diagram of an optical energy transmission system for a laser processing machine to which the hollow optical waveguide body according to the present invention is applied, and FIG. 5 is a cross-sectional view of the hollow optical waveguide body according to the present invention with increased flexibility. 6 is a cross-sectional view of a hollow optical waveguide body with improved linearity according to the present invention. In the figure, 1 is germanium, 2 is a germanium inner layer nickel hollow optical waveguide, 3.4 is an aluminum pipe, 5 is an aluminum boiler, 6 is a sealing tape, 7 is a Watt bath, 8 is a nickel electrode, 9 is a germanium inner layer nickel hollow optical waveguide. wave path, 10 is a Nila gel hollow tube, 11 is a hollow optical waveguide body, 1
5 is cooling water, 16 is cooling gas, 18 is a cap, 19 is a water supply cap, 20 is a drain cap, and 24 is an air cooling holder.

Claims (1)

[Scope of Claims] 1. A hollow optical waveguide body characterized in that at least two or more hollow tubes are integrated with the hollow optical waveguide in the axial direction around the outer periphery of the hollow optical waveguide for transmitting optical energy. 2. In order to flow a cooling medium into the hollow tube integrated on the outer periphery of the hollow optical waveguide, the openings of the hollow tubes on the optical energy output end side of the hollow optical waveguide are interconnected, and the openings of the hollow tube are connected to each other to form an inlet/outlet for the cooling medium. 2. The hollow optical waveguide body according to claim 1, wherein: is formed on the optical energy incident end side of the hollow optical waveguide. 3. After forming a hollow optical waveguide for transmitting optical energy, at least one conductive hollow tube is closely attached in the axial direction on the outer circumference of the hollow optical waveguide, and the mechanical strength is increased by electroplating. A metal film is formed with a thickness sufficient to obtain the conductive hollow tube, and then only the conductive hollow tube is removed using a selective etching solution, and the hollow tube integrated on the outer periphery of the hollow optical waveguide is removed. 1. A method for manufacturing a hollow optical waveguide body, the method comprising forming a hollow optical waveguide body having the following properties. 4. The hollow optical waveguide body according to claim 3, wherein a dielectric-incorporated metal hollow optical waveguide is used as the hollow optical waveguide, an aluminum pipe is used as the conductive hollow tube, and caustic soda is used as the etching solution. Production method. 5. The method of manufacturing a hollow optical waveguide body according to claim 4, wherein germanium is used for the interior dielectric of the dielectric interior metal hollow optical waveguide, and nickel or silver is used for the metal.