JPH0521885A - Gas laser tube device - Google Patents

Abstract

PURPOSE:To provide a gas laser tube device capable of stabilization of a laser light output level. CONSTITUTION:A gas laser tube device is adapted such that a laser light output is detected and a discharge current in a laser tube 11 is detected, and a signal corresponding to the discharge current is transmitted to mirror inclination adjusting mechanisms 21,22 to automatically adjust the inclination of a mirror such that the laser tube discharge current is minimum in a range where the laser light output is kept substantially unchanged even though the inclination of the mirror is varied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser tube device, and more particularly to an improvement of a device having a mirror tilt adjusting mechanism.

[0002]

2. Description of the Related Art A gas laser tube apparatus is generally constructed as shown in FIG. That is, the gas laser tube 11 is fixed to the support frame 12, and the high reflection mirror 13 and the output mirror 14 are fixed to the mirror fixing plates 15 and 16 on both sides of the discharge path. The energizing power is supplied from a power source (not shown). In operation, the laser medium is excited by the energizing power, and the light is amplified by the high-reflection mirror and the output mirror that form the optical resonator. Part of the light passes through the output mirror and is extracted as laser light.

Recently, in order to stabilize the output level of laser light or suppress fluctuations in the emission direction of the laser beam, a structure in which a part of the output laser light is split by a beam splitter has been put into practical use. In such an apparatus, the branched laser light is photoelectrically converted by the light receiving element, and the corresponding output electric signal is transmitted to the power supply control circuit. This control circuit controls the discharge current to keep the laser output level constant.

Further, as indicated by a dotted line 15a in the figure, the support frame and the mirror fixing plate are deformed by heat generated from the laser tube, and the inclination of each mirror is changed to lower the laser light output level. Or the laser beam emission direction may fluctuate. In order to automatically correct the tilt of the mirror, a mirror tilt adjusting pulse motor is provided on at least one of the mirror fixing plates, and the pulse motor is driven and controlled by the output electric signal corresponding to the laser beam branched by the beam splitter to control both mirrors. Devices that are configured to control the parallelism are also known.

[0005]

By the way, the change of the laser light output level with respect to the optical parallelism of the pair of mirrors forming the optical resonator is shown in FIG. 5 while the discharge current of the laser tube is kept constant. The relationship is as shown. That is, when the parallelism of the mirrors is deteriorated from the position 0 where both mirrors are completely optically parallel, the laser light output level is sharply lowered. Therefore, even if the parallelism of the mirror changes even slightly, the laser light output level changes greatly.
It is easy to follow the mirror tilt adjusting mechanism. Therefore, there is an inconvenience that variations in the laser light output level and the laser beam emission direction cannot be sufficiently suppressed. Alternatively, it becomes difficult to perform feedback control by discriminating between the fluctuation of the laser light output level due to the fluctuation of the biasing power and the fluctuation of the output level due to the fluctuation of the parallelism of the mirror. This invention
It is an object of the present invention to provide a gas laser tube device capable of stabilizing the laser light output level by eliminating the above inconvenience.

[0006]

According to the present invention, a laser light output is detected and a discharge current of a laser tube is detected, and a signal corresponding to the discharge current is transmitted to a mirror tilt adjusting mechanism to slightly tilt the mirror. It is a gas laser tube apparatus configured such that the tilt of the mirror is automatically adjusted so that the laser beam output does not change very rapidly even if it is changed and the laser tube discharge current is minimized.

[0007]

According to the present invention, the laser light output changes little even if the tilt of the mirror slightly changes. Therefore, the optical parallelism of the mirror can be easily controlled to follow the optimum state, and the laser light output level can be stabilized. Can be maintained at.

[0008]

Embodiments will be described below with reference to the drawings. The same parts are denoted by the same reference numerals.

The gas laser tube device shown in FIG. 1 has the following configuration. A laser tube 11 is housed in the laser head portion 17, and a high reflection mirror 1 is provided on one side across the gas discharge path.
3, the output mirror 14 is arranged on the other side. The high-reflecting mirror 13 is a mirror tilt adjusting mechanism 21, 2 such as a pulse motor.
2 adjusts the tilt in the horizontal and vertical directions. Further, the trigger circuit section 23 is connected to the anode of the laser tube 11. A beam splitter 24 is arranged on the output laser optical path, and a photoelectric conversion element 25 is installed on the branch optical path. In the power supply unit 18, the commercial power supply 26 is connected to the rectifier circuit unit 27 and the heater transformer 28, and the output thereof is connected to the cathode of the laser tube 11. The output of the rectification circuit unit 27 is supplied to the power supply stabilization circuit unit 29 and further supplied to the power supply control circuit unit 30. The output of the power supply control circuit section 30 is supplied to the trigger circuit section 23 of the laser head section 17 and the AD converter 31 of the mirror tilt control section 19. The output signal of the photoelectric conversion element 25 is supplied to the comparison circuit section 32, and its output is supplied to the power supply control circuit section 30. The output of the A / D converter 31 is the central control unit.
It is adapted to be supplied to the drive control unit 34 which drives the mirror tilt control mechanism via 33.

In operation, a part of the output laser light is split by the beam splitter 24, photoelectrically converted by the photoelectric conversion element 25, and the output electric signal is supplied to the comparison circuit section 32 for comparison calculation with the reference value signal. To be done. Then, the output signal is transmitted to the power supply control circuit unit 30. In the power supply control circuit unit 30, the discharge current is controlled so that the laser light output is kept stable. Therefore, the power supply control circuit section 30 simultaneously monitors the discharge current and supplies the analog signal to the A-D converter 31 of the mirror tilt control section 19.
Then, it is converted into a digital signal by the A / D converter 31 and transmitted to the central control unit 33. The central control unit 33 compares the calculated value with a reference value and performs an arithmetic process.
Be transmitted to. The drive control unit 34 drives the mirror tilt adjusting mechanisms 21 and 22. This controls the tilt of the mirror and adjusts the optical parallelism of the optical resonator.

The central control unit 33 supplies a control signal to the drive control unit 34 so as to find the tilt position of the mirror at which the discharge current of the laser tube becomes the minimum. The reason is that, as shown in FIG. 2, since the discharge current is controlled by the power supply control circuit unit 30 so that the laser light output becomes constant, the discharge current becomes minimum at the position 0 where there is no tilt between the two mirrors. This is because the laser light output level is substantially constant in the range A where the mirror tilt is to some extent. Therefore, once the parallelism of the mirror is set to the position where the discharge current is the minimum, the laser light output level can be suppressed to a negligible level even if a slight mirror tilt occurs. As described above, since the discharge current is controlled so that the laser light output is almost constant, the fluctuation of the laser light output with respect to the change of the tilt of the mirror does not become too sensitive. Is easy.

In the embodiment shown in FIG. 3, the output electric signal photoelectrically converted by the photoelectric conversion element 25 is used as a comparison circuit section of the power source section.
32 to the mirror tilt controller 19 at the same time
The configuration is such that it is supplied to the central control unit 33 via the -D converter 31. Thereby, the central controller 33 controls both the magnitude of the discharge current and the magnitude of the laser light output level to control the tilt of the mirror.

Thus, the laser light output is detected, the discharge current of the laser tube is detected, and a signal corresponding to this discharge current is transmitted to the mirror tilt adjusting mechanism so that the laser light output is substantially constant even if the tilt of the mirror is changed. The tilt of the mirror is automatically adjusted so that the discharge current of the laser tube is minimized in the range.

[0014]

As described above, according to the present invention,
Even if the tilt of the mirror slightly changes, the change of the laser light output is small. Therefore, the optical parallelism of the mirror can be easily controlled to the optimum state, and the laser light output level can be stably maintained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a characteristic diagram of its operation.

FIG. 3 is a block diagram showing another embodiment of the present invention.

FIG. 4 is a side view showing a general device.

FIG. 5 is an operation characteristic diagram showing the relationship between the tilt of the mirror and the laser output.

[Explanation of symbols]

11 ... Gas / laser tube, 13 ... High-reflecting mirror, 14 ... Output mirror, 17 ... Laser head section, 18 ... Power supply section, 19 ... Mirror tilt control section, 21, 22 ... Mirror tilt control mechanism, 25 ... Photoelectric conversion element.

Claims (1)

Claim: What is claimed is: 1. A high reflection mirror arranged on one side of the discharge path of the gas laser tube and an output side mirror arranged on the other side, and at least one of these mirrors is tilted. A gas / laser tube device having a structure for adjusting a mirror tilt adjusting mechanism and a power supply device for supplying energizing power to the laser tube, and controlling the mirror tilt adjusting mechanism by detecting a laser light output of the gas laser tube. The laser light output is detected and the discharge current of the laser tube is detected, and a signal corresponding to the discharge current is transmitted to the mirror tilt adjusting mechanism so that the laser light output is substantially constant even if the mirror tilt is changed. A gas laser tube apparatus, wherein the tilt of the mirror is automatically adjusted so that the laser tube discharge current is minimized within the range.