# US 2008/0304533 A1 · Startup method for gas laser unit and gas laser unit having startup function

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2008/0304533 A1
- Document ID: US20080304533A1
- Status: Published application
- Kind: A1
- Application number: 12/132,905
- Filed: 2008-06-04
- Published: 2008-12-11
- Earliest claimed: 2007-06-11
- Assignees: Fanuc Corporation
- Inventors: Minoru ANDO; Hajime Ikemoto
- Web page: https://patentgrep.com/patent/US20080304533A1

## CPC

- H01S 3/0014: {Monitoring arrangements not otherwise provided for (photometry G01J1/00, e.g. G01J1/4257; radiation pyrometry G01J5/00; measuring coherence of light G01J9/00; measuring wavelength of light G01J9/00, e.g. G01J9/0246; measuring optical pulses G01J11/00; calorimetrically measuring power of laser beams G01K17/003)}
- H01S 3/036: Means for obtaining or maintaining the desired gas pressure within the tube, e.g. by gettering, replenishing; Means for circulating the gas, e.g. for equalising the pressure within the tube {(H01S3/031 takes precedence)}
- H01S 3/097: by gas discharge of a gas laser
- H01S 3/0951: by increasing the pressure in the laser gas medium
- H01S 3/0975: using inductive or capacitive excitation
- H01S 3/10069: {Memorized or pre-programmed characteristics, e.g. look-up table [LUT]}
- H01S 3/22: Gases
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL

## Abstract

A startup method capable of easily and inexpensively activating a laser oscillator by limiting an output current of a high-frequency power supply, without using a particular element or a complicated system, even when the laser oscillator is activated in a low-temperature environment, and a gas laser unit having such a function. According to the normal pressure control, the laser gas is gradually increased from pressure p1 to pressure p2. However, in the invention, when DC current reaches a certain threshold at time t3, a feedback control of the laser gas is executed after time t3 such that the DC current does not exceed the threshold. In this case, the laser gas pressure is controlled so as to increase to pressure p2′ which is smaller than pressure p2.

## Claims

### Claim 1

A startup method for a discharge excitation gas laser unit capable of generating a laser by circulating a laser gas in a laser discharge tube and generating high-frequency discharge of the laser gas, the method comprising the steps of:
previously storing an output current characteristic, as a normal current characteristic, of a DC power supply part of a laser power supply unit of the gas laser unit when the gas laser unit is normally activated;
detecting an output current of the DC power supply part of the laser power supply unit while the gas laser unit is activated; and
controlling the pressure of the laser gas within the laser discharge tube such that the detected output current of the DC power supply part does not exceed a threshold which is determined based on the normal current characteristic.

### Claim 2 (depends on 1)

The startup method as set forth in claim 1, wherein the step of controlling the pressure of the laser gas comprises reducing the pressure of the laser gas within the laser discharge tube when the detected output current of the DC power supply part reaches the threshold.

### Claim 3

A discharge excitation gas laser unit capable of generating a laser by circulating a laser gas in a laser discharge tube and generating high-frequency discharge of the laser gas, the gas laser unit comprising:
a storing part for previously storing an output current characteristic, as a normal current characteristic, of a DC power supply part of a laser power supply unit of the gas laser unit when the gas laser unit is normally activated;
a detecting part for detecting an output current of the DC power supply part of the laser power supply unit while the gas laser unit is activated; and
a pressure controlling part for controlling the pressure of the laser gas within the laser discharge tube such that the output current of the DC power supply part detected by the detecting part does not exceed a threshold which is determined based on the normal current characteristic stored in the storing part.

### Claim 4 (depends on 3)

The gas laser unit as set forth in claim 3, wherein the pressure controlling unit is configured to reduce the pressure of the laser gas within the laser discharge tube when the detected output current of the DC power supply part reaches the threshold.

### Claim 5 (depends on 3)

The gas laser unit as set forth in claim 3, wherein the gas laser unit comprises a matching unit having a fixed-capacity condenser.