Gas laser oscillator and method of measuring laser gas replacement amount

Abstract

A gas laser oscillator includes a supply-side valve for regulating a laser gas supply to a gas chamber, an exhaust-side valve for regulating a laser gas exhaust from the gas chamber, a gas pressure measuring device for measuring a pressure in the gas chamber, and a control device functioning as a laser gas replacement measuring device. The control device makes a first measurement and a second measurement of the pressure in the gas chamber by a gas pressure measuring device at a predetermined time interval during the vacuuming or purging of the gas chamber, and determines the laser gas replacement amount per unit time during the laser oscillating operation, based on the results of the first and second measurements.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will be described in more detail below based on the preferred embodiments of the present invention with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram showing a configuration of a gas laser oscillator according to a first embodiment of the present invention;

FIG. 2 is a graph showing a pressure change when laser gas is exhausted from a gas chamber of the gas laser oscillator shown in FIG. 1;

FIGS. 3 and 4 are flowcharts showing a procedure for determining a laser gas replacement amount per unit time based on the laser gas pressure in the gas chamber measured at the time of exhaust of the laser gas in the gas laser oscillator according to the first embodiment;.

FIG. 5 is a schematic diagram showing a configuration of a gas laser oscillator according to a second embodiment of the present invention;

FIG. 6 is a graph showing a pressure change when an interior of a gas chamber of the gas laser oscillator shown in FIG. 5 is purged; and

FIGS. 7 and 8 are flowcharts showing a procedure for determining a laser gas replacement amount per unit time based on the laser gas pressure in the gas chamber measured at the time of purging in the gas laser oscillator according to the second embodiment.

Claims

1. A gas laser oscillator comprising a gas chamber for containing laser gas, a supply-side valve for regulating a supply of the laser gas to said gas chamber, an exhaust-side valve for regulating an exhaust of the laser gas from said gas chamber, and a gas pressure measuring device for measuring pressure in said gas chamber, said laser gas in said gas chamber being replaced while controlling said supply-side valve and said exhaust-side valve during the time of generating a laser light by exciting the laser gas in said gas chamber, wherein said gas laser oscillator further comprises a laser gas replacement amount measuring device, said laser gas replacement amount measuring device making a first measurement and a second measurement of the pressure in said gas chamber by means of said gas pressure measuring device at a predetermined time interval at one of the time when the laser gas in said gas chamber is exhausted by closing said supply-side valve with said exhaust-side valve opened and the time when said gas chamber is purged by closing said exhaust-side valve and opening said supply-side valve after the exhausting of said gas chamber, and determining the laser gas replacement amount per unit time during the laser oscillating operation based on results of the first and second measurements.

2. The gas laser oscillator according to claim 1, wherein, when P0 is an average pressure of the laser gas in said gas chamber during the laser oscillating operation, V0 is a volume of said gas chamber, t1 is a time of the first measurement, t2 is a time of the second measurement, P1 is a pressure in said gas chamber measured by said gas pressure measuring device at time t1, P2 is a pressure in said gas chamber measured by said gas pressure measuring device at time t2, and Q is the laser gas replacement amount per unit time, said laser gas replacement amount measuring device determines the laser gas replacement amount Q per unit time from the pressure in said gas chamber measured during the gas exhausting process by the following equation: Q=P0·V0/(t2−t1)·1n(P1/P2).

3. The gas laser oscillator according to claim 1, wherein, when V0 is a volume of said gas chamber, t1 is a time of the first measurement, t2 is a time of the second measurement, P1 is a pressure in said gas chamber measured by said gas pressure measuring device at time t1, P2 is a pressure in said gas chamber measured by said gas pressure measuring device at time t2, and Q is the laser gas replacement amount per unit time, said laser gas replacement amount measuring device determines the laser gas replacement amount Q per unit time from the pressure in said gas chamber measured during the purging process by the following equation: Q=V0·(P2−P1)/(t2−t1).

4. The gas laser oscillator according to claim 1, further comprising a display device for displaying the laser gas replacement amount per unit time determined by said laser gas replacement amount measuring device.

5. The gas laser oscillator according to claim 4, further comprising a storage device for storing the laser gas replacement amount per unit time determined by said laser gas replacement amount measuring unit, wherein the laser gas replacement amount per unit time stored in said storage device is displayed on said display device.

6. The gas laser oscillator according to claim 2, wherein said laser gas replacement amount measuring device automatically calculates the laser gas replacement amount when the laser gas is exhausted from said gas chamber.

7. The gas laser oscillator according to claim 3, wherein said laser gas replacement amount measuring device automatically calculates the laser gas replacement amount when said gas chamber is purged.

8. A method of measuring a laser gas replacement amount per unit time during a laser oscillating operation in a gas laser oscillator in which a laser gas in a gas chamber is replaced while controlling a supply of the laser gas to said gas chamber and an exhaust of the laser gas from said gas chamber during the time of generating a laser light by exciting the laser gas in said gas chamber, said method characterized by comprising the steps of: stopping the supply of the laser gas to said gas chamber;exhausting the laser gas in said gas chamber with the laser gas supply to said gas chamber stopped;making a first measurement of the pressure in said gas chamber in said exhausting step;making a second measurement of the pressure in said gas chamber at a predetermined time interval from the first measurement; anddetermining the laser gas replacement amount per unit time during the laser oscillation operation, based on the results of the first and second measurements.

9. The method according to claim 8, wherein, when P0 is an average pressure of the laser gas in said gas chamber during the laser oscillating operation, V0 is a volume of said gas chamber, t1 is a time of the first measurement, t2 is a time of the second measurement, P1 is a pressure in said gas chamber measured at time t1, P2 is a pressure in said gas chamber measured at time t2, and Q is the laser gas replacement amount per unit time, the laser gas replacement amount Q per unit time is determined from the pressure in said gas chamber measured during the exhausting step by the following equation: Q=P0·V0/(t2−t1)·1n(P1/P2).

10. A method of measuring a laser gas replacement amount per unit time during a laser oscillating operation in a gas laser oscillator in which a laser gas in a gas chamber is replaced while controlling a supply of the laser gas to said gas chamber and an exhaust of the laser gas from said gas chamber during the time of generating a laser light by exciting the laser gas in said gas chamber, said method characterized by comprising the steps of: stopping the supply of the laser gas to said gas chamber;exhausting the laser gas in said gas chamber with the laser gas supply to said gas chamber stopped;purging said gas chamber by supplying the laser gas to said gas chamber with the exhaust of the laser gas from said gas chamber stopped, after the exhausting step;making a first measurement of the pressure in said gas chamber in the purging step;making a second measurement of the pressure in said gas chamber at a predetermined time interval from the first measurement; anddetermining the laser gas replacement amount per unit time during the laser oscillation operation, based on the results of the first and second measurements.

11. The method according to claim 10, wherein, when V0 is a volume of said gas chamber, t1 is a time of the first measurement, t2 is a time of the second measurement, P1 is a pressure in said gas chamber measured at time t1, P2 is a pressure in said gas chamber measured at time t2, and Q is the laser gas replacement amount per unit time, the laser gas replacement amount Q per unit time is determined from the pressure in said gas chamber measured during the purging step by the following equation: Q=V0·(P2−P1)/(t2−t1).