JPS61236178A - Laser oscillator - Google Patents

Abstract

PURPOSE:To prevent cooling water from condensing dews on the surface of an output mirror, by winding a self-controllable heater formed of a conductive plastics whose resistance is increased by the increase in temperature, around a member for fixing and supporting the output mirror on the atmospheric side. CONSTITUTION:A heater 50 formed of a conductive plastics is adapted to have self- controllability for holding the temperature thereof at a given value. For example, when the temperature is raised, it generates less heat for preventing the temperature from increasing further. The heat generated by the heater is conducted and raises the atmospheric temperature within a cylinder 29. On the other hand, the resistance and the voltage of a power supply 44 are previously set such that the temperature is not raised so much as to cause dews condensation on an output mirror 25. When laser light is emitted, the temperature within the cylinder 29 is raised slightly by scattered light of the laser. The heat is conducted to the heater 50 to raise the temperature thereof. Consequently, the heater 50 decreases the heat generation by its self- controllability, whereby the temperature within the cylinder 29 is held at a fixed value. In such a manner, the temperature near the surface of the output mirror 25 can be maintained such that no dew condensation is caused on the mirror, without detecting the temperature within the cylinder 29 and without opening or closing a switch 45.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a cooling structure for an output mirror, and more particularly to a support structure that prevents dew condensation on a mirror support portion caused by cooling water.

[Background of the invention]

In conventional devices, in order to prevent damage to the output mirror due to condensation vlrVC, a groove shape is provided in the support member to prevent the generated condensation from reaching the output mirror, and to prevent condensation from reaching the output mirror and causing damage. (Utility Model Application Publication No. 55-27935)
Alternatively, a structure has been proposed in which dew condensation is prevented by irradiating the output mirror with lamp light and increasing the ambient temperature near the output surface. However, the latter method has drawbacks such as the need to control the lighting and extinguishing of the lamp.

[Purpose of the invention]

An object of the present invention is to provide a laser oscillator that has an improved support structure for an output mirror that does not cause dew condensation on the surface of the output mirror due to cooling water.

[Summary of the invention]

The output mirror of the laser oscillator of the present invention is placed on the atmosphere side of the support part, and a controllable heater whose resistance value increases as the temperature rises is attached, and current is applied to increase the atmospheric temperature near the output mirror surface to prevent dew condensation. To prevent.

[Embodiments of the invention]

In a gas laser oscillator, a pair of mirrors facing each other is placed in a gas space excited by an electric discharge or the like.

Laser light is output from one of the mirrors (output R) VC.

Figures gX1 and 2 show the output mirror support according to the present invention.

The output mirror 25 directs a portion of the laser light within the laser oscillator maintained in a low vacuum to the atmosphere to generate a laser output 40. At this time, it is necessary to cool the output mirror in order to exhaust the heat generated on and inside the output mirror. That is, the support 7 flange 10 attached to the oscillator is provided with a cold water channel 12, and the heat generated in the oscillator 25 is transferred to the heat transfer ring 26.
Current is transmitted from the holder 20 via the support 7 flange and is cooled. The heat transfer ring 26Vc is, for example, “-
It is known that heat transfer from 25 and vacuum sealing performance can be ensured by using a sufficiently soft metal material such as y-dium wire. (Hence, the holder 20Vc is attached with the force of the bolt 30.

Further, a cylinder 29 formed of a metal material is similarly fixed by Vc30, and a heater 50 is wound around the outer circumference of the cylinder 29.
50 as a power supply circuit, a power supply 44 and an operation switch 4
5 is connected. The cylinder 29 is normally installed as a safety protection cylinder for the output beam 40, regardless of the present invention.

The heater 50 is a self-regulating heater made of a polymeric material that has recently been in the spotlight as a polymeric functional material. Its structure is shown in FIG. 4, and its characteristics are shown in FIG. 50 has two conductors 51 and a resistor 52 disposed between the two conductors 510, and a shield layer 55 made of an insulating layer 53 (material; urethane, etc.), a sheath layer 54 (polyethylene), and a copper braid on the outside thereof. ．． A polyethylene sheath 56 is provided as the outermost layer to shield and mechanically protect the resistor. Resistor 52Ifi is made of a plastic semiconductor material and allows current to flow in response to a voltage applied between conductors 51, but its resistance value depends on the temperature of 52 and has the characteristic that the current decreases significantly as the temperature rises. ing. Therefore, when a constant voltage is applied to the temperature, the heat generation output is the custom-made figure shown in Figure 3. When the heater temperature rises, the heat generation amount decreases, suppressing the temperature rise, and maintaining the heater temperature at a constant value. This will demonstrate self-control.

Therefore, the heat generated by 50 is conducted to 29 and the ambient temperature inside 29 rises, but the resistance value and the voltage of power source 44 are set so that this temperature is at a value that does not cause dew condensation on the surface of 25. Also, between 25 and 29 VC is a thermal insulator (
Since the presser 28 made of plastic is provided, a heat insulating effect can be obtained, and the heat generated at 50°C can be directly transferred to 52vc.
The heat effect of 25.\\ due to the heat generation of 500 is limited to the effect of increasing the temperature near the surface of the reed 25, and does not impair the water cooling effect of the reed 25. When the laser oscillator is in operation, no condensation occurs on the surface of the 25 as described above when the laser beam is not output, and when the laser beam is output, a small amount of laser light is scattered within the 29. The temperature inside rises and the heat is 2
9 to 50. Therefore, the temperature of 50 increases, and due to the above-mentioned self-control property of 50, the amount of heat generated by 50 decreases, and the temperature inside 29 is maintained at a constant value.

Therefore, the temperature near the surface of the output mirror 25 can be maintained at a condition that does not cause dew condensation, without detecting the temperature inside the output mirror 29 and controlling the opening/closing of the switch 45.

〔Effect of the invention〕

1. It is possible to prevent dew condensation from occurring on the output mirror, and damage to the output mirror can be prevented.

2. The self-control function of the heater eliminates the need to control energization based on temperature detection, simplifying the configuration and improving reliability.

[Brief explanation of the drawing]

Fig. 1 is a partial side sectional view of a gas laser generator according to an embodiment of the invention, Fig. 2 is a plan view of Fig. 1 viewed from the right side,
3 is a temperature output percentage diagram of the heater of FIG. 1, and FIG. 4 is a side sectional view of the beater of FIG. 1. lO...Support 7 lange, lla, llb...Cooling water inlet/outlet, 12...Cooling water channel, 13...O ring for sealing, 20...Holder, 25...Output mirror, 26...
...heat transfer ring, 27...0 ring, 28...presser, 29...tube, 30...volt, 35...volt, 40...laser output. 44... Power supply, 45... Switch, 50... Beater, 51... Conductor, 52... Resistor (plastic semiconductor), 53... Insulator, 54... Sheath, 55
・°・Copper braided wire, 56...sheath

Claims (1)

[Claims] 1. In the output mirror support structure of a laser oscillator that operates while the output mirror is constantly water-cooled, the output mirror is fixed from the atmosphere side to the supporting material, and a self-containing structure using conductive plastic whose resistance value increases as the temperature rises is used. A laser oscillator characterized by having a controllable heater wound around it.