JPH0760912B2 - Laser output controller - Google Patents

Description

The present invention relates to a laser output control device for controlling laser output at high speed.

[Prior art]

FIG. 4 is a schematic configuration diagram showing a laser output control device in a conventional carbon dioxide gas laser device disclosed in Japanese Patent Laid-Open No. 60-52072.

In the figure, (1) is a container filled with a laser medium gas containing carbon dioxide, (2A) and (2B) are a pair of electrodes provided in the container (1), and (3) is electrodes (2A) and (2B). Power source for applying a high voltage to (4), (4) is an electric discharge generated by applying a high voltage to electrodes (2A) and (2B), and (5) reflects most of the laser light but is about 1%. A total reflection mirror having a property of transmitting light to a degree, and a partial transmission mirror (6).
(7) is a laser beam output from the partial transmission mirror (6) to the outside, (8) is a detection laser beam output from the total reflection mirror (5), and the intensity of the detection laser beam (8) is the laser beam (7). ) Is proportional to the intensity of. (9) is an integrating sphere whose inner surface is a completely diffusing surface, (10) is an input port for making the detection laser light (8) incident on the integrating sphere (9), and (11) is diffusing in the integrating sphere (9). Output port for outputting the laser beam generated, (12) a micro laser detector made of, for example, a thermopile installed in the output boat (11), (13) an output command value output from an output setting device (not shown), (14) ) Is a comparator, and (15) is an amplifier.

The laser output control device in the conventional carbon dioxide gas laser device is configured as described above, and a high voltage is applied to the pair of electrodes (2A) and (2B) from the power source (3) to generate discharge (4) to generate laser medium gas. To emit laser light having a wavelength of 10.6 μm. The emitted laser light is repeatedly reflected between the total reflection mirror (5) and the partial transmission mirror (6) provided in parallel to cause laser oscillation, and the laser light (7) is emitted from the partial transmission mirror (6). Output to the outside. On the other hand, the total reflection mirror (5) outputs a detection laser light (8) of about 10 to 50 W which is proportional to the intensity of the laser light (7) output from the partial transmission mirror (6), and the integrating sphere (9) Input boat (10) to integrating sphere (9)
It is incident on the inside. The detection laser light (8) incident on the integrating sphere (9) repeatedly repeats a large number of reflections on the inner surface of the integrating sphere (9) to be uniformly diffused and dimmed, and a small laser detector (12) installed on the output boat (11). ). The attenuation rate of the integrating sphere (9) with respect to the micro laser detector (12) is about 1/10000 when the diameter of the integrating sphere (9) is about 100 mm and the diameter of the light receiving surface of the micro laser detector (12) is about 1 mm. Therefore, for example, when the integrating sphere (9) receives the detection laser beam (8) of about 50 W, the input of the minute laser detector (12) becomes about 5 mW. The laser light input to the minute laser detector (12) is converted into an electric signal, and this electric signal is compared with a predetermined laser light output command value (13) by a comparator (14), and the deviation signal is calculated. By controlling the output voltage or output current of the power supply (3) after amplification by the amplifier (15), the excitation intensity of the laser medium gas is controlled, and the intensity of the laser light (7) is kept substantially constant.

[Problems to be solved by the invention]

However, since the micro laser detector (12) is composed of a thermopile, etc., the sensitivity changes when the ambient temperature changes,
Therefore, there is a problem that the laser output control is not accurately performed when the temperature greatly changes such as in summer and winter.

The present invention has been made for the purpose of improving the above-mentioned problems, and in a laser output control device having an integrating sphere and a micro laser detector, the micro laser detector has a temperature compensation function, so that This prevents fluctuations in output characteristics due to temperature changes.

A laser output control device according to the present invention is a laser output control device having an integrating sphere for diffusing incident laser light and a minute laser detector for detecting the laser light diffused by the integrating sphere. An ambient temperature detector having substantially the same characteristics as the detector, the ambient temperature detector is arranged at a position for detecting the ambient temperature, and the minute laser detector and the ambient temperature detector are detected by these detectors. It is connected so as to have a temperature compensation function by the interaction of the vessels.

Further, the laser output control device according to the present invention includes an integrating sphere for diffusing the incident laser light, a detector main body for detecting the laser light diffused by the integrating sphere, and a first thermoelectric device arranged on the detector main body. A second having substantially the same properties as the pair
Of the thermocouple, the detector body, and a detector body holding case for holding the second thermocouple, and a microlaser detector, in which the detector body outputs the integrating sphere. In a laser output control device having a case for holding a minute laser detector held so as to be positioned at a port, the second thermocouple in the minute laser detector is arranged at a position where ambient temperature can be detected, and The first thermocouple and the second thermocouple are connected in series so as to have a temperature compensation function by the interaction of these thermocouples.

[Action]

According to the present invention, the micro laser detector is not affected by the change in ambient temperature, the output of the micro laser detector does not fluctuate, and the laser output can be accurately controlled.

Example of Invention

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention,
In the figure, (1), (2A), (2B) and (4) to (1
1) is the same as the conventional one. (12) is a first thermocouple (101a) which is a detector main body for detecting the laser light diffused by the integrating sphere (9) and the first thermocouple (101a)
The micro laser detector has a case (104) for holding the main body of the detector, and (18) is a case for holding the micro laser detector made of aluminum or copper. This case (18) for holding the micro laser detector is used for the micro laser detector (12).
The side surfaces of the micro laser detector (12) are housed in close contact with each other, and an opening (18a) is provided on the light receiving surface of the micro laser detector (12) so that the opening (18a) is positioned at the output port (11) of the integrating sphere (9). To install. Reference numeral (101b) is a second thermocouple having the same temperature characteristics as the first thermocouple (101a), and is embedded around the minute laser detector holding case (18). In addition, the second thermocouple (101b) cooperates with the first thermocouple (101a) so that the temperature of the minute laser detector (12) can be compensated (so that it has an inverse characteristic). It is connected in series with the pair (101a). Further, (21) is an output line of the first thermocouple (101a) and the second thermocouple (101b).

The thermopile used for laser output detection is a well-known thermopile in which a large number of thermocouples are connected in series and high temperature parts (measurement parts) are gathered and arranged at one place (“laser practical technology”).
See page 131). FIG. 3 illustrates a connection portion around the thermopile in the invention of the present application.

In the figure, four hatched fan-shaped portions represent the high temperature portion (measurement portion) of the thermopile, and symbols 21 and 22 represent dissimilar metals, both of which constitute a single thermocouple. Symbols H (four locations) in the figure are high temperature (measurement) contact points (hereinafter referred to as "hot junctions") of this thermocouple, and symbol C is a low temperature (ambient temperature measurement) contact (hereafter). "Cold junction") is shown.

When the thermopile is used in a normal use method, the number of cold junctions is one less than the number of hot junctions, so thermoelectromotive force is generated even when the laser beam is not irradiated. By making the number the same as the number of hot junctions, it is possible to perform temperature compensation.

FIG. 3 (a) corresponds to FIG. 2 and shows a case where a cold junction B (corresponding to 101b in FIG. 2) is added in the thermopile. 3 (b) corresponds to FIG. 1 and shows a case where a cold junction D (corresponding to 101b in FIG. 1) is provided outside the thermopile.

In the laser output control circuit configured as described above,
Even if the holder temperature changes due to the ambient temperature change, the thermocouples (101a) and (101b) perform temperature compensation, so the detector (1
The output characteristic of 2) can be maintained constant, and the output of the laser beam (7) can be accurately controlled by the stable output signal of the minute laser detector (12).

FIG. 2 shows another embodiment of the present invention, in which only the microdetector (12) is enlarged. In the figure (10
4) is the case of the micro detector, (101b) is the case (104)
It is a thermocouple having the same characteristics as the thermocouple (101a) for detecting a minute laser, which is mounted so as to be in thermal contact with.

As described above, a thermocouple for temperature compensation may be provided in the minute laser detection element.

In the above description, the thermopile was used as the detection element as the micro laser detector, but in the carbon dioxide laser, gold / germanium element, mercury / cadmium / telluride element, pyroelectric effect element, and in YAG laser, silicon photosensor etc. Needless to say, it can be used.

As described above, according to the present invention, in the laser output control device having the integrating sphere for diffusing the incident laser light and the minute laser detector for detecting the laser light diffused by the integrating sphere, An ambient temperature detector having substantially the same characteristics as the detector is provided, and the ambient temperature detector is
It is arranged at a position for detecting the ambient temperature, and since the minute laser detector and the ambient temperature detector are connected so as to have a temperature compensation function by the interaction of these detectors, a heater or a cooler is not necessary. The temperature compensation of the micro laser detector can be performed, and the temperature compensation of the micro laser detector can be performed with a simple and inexpensive structure.

According to the invention, the integrating sphere that diffuses the incident laser light, the detector body that detects the laser light diffused by the integrating sphere, and the first thermocouple disposed in the detector body are substantially provided. A micro laser detector having a second thermocouple having the same characteristics, a detector main body, and a detector main body holding case for holding the second thermocouple, and the micro laser detector for detecting the micro laser detector. In a laser output control device having a microlaser detector holding case for holding the main body of the instrument so that it is positioned at the output port of the integrating sphere, the second thermocouple in the microlaser detector detects ambient temperature. The first thermocouple and the second thermocouple.
Since they are connected in series so as to have a temperature compensation function by the interaction of these thermocouples, it becomes possible to perform temperature compensation for the micro laser detector without the need for a heater or cooler, and The temperature compensation of the minute laser detector can be performed with a simple and inexpensive structure. Further, since the second thermocouple is held in the detector main body holding case, it can be handled together with the micro laser detector, so that the second thermocouple can be handled easily and the first thermocouple can be handled easily. Since the disconnection of the connection line with the thermocouple is less likely to occur and it is not necessary to bury the second thermocouple in the case for holding the minute laser detector, there is an effect that the device can be easily assembled.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is a schematic configuration diagram showing another embodiment of the present invention, and FIG. 3 is a schematic configuration diagram showing a conventional laser output control device. In the figure, (1) is a container, (2A) and (2B) are electrodes,
(3) is a power source, (5) is a total reflection mirror, (6) is a partial reflection mirror, (9) is an integrating sphere, (12) is a small laser detector, (1
4) is a comparator, (15) is an amplifier, (18) is a case for holding a micro laser detector, (101a) is the first thermocouple, (101b)
Is a second thermocouple, and (104) is a detector body holding case. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] 1. A laser output control device having an integrating sphere for diffusing incident laser light and a micro laser detector for detecting laser light diffused by the integrating sphere, wherein the micro laser detector is substantially the same as the micro laser detector. An ambient temperature detector having the same characteristics is provided, the ambient temperature detector is arranged at a position for detecting the ambient temperature, and the minute laser detector and the ambient temperature detector are arranged by the interaction of these detectors. A laser output control device, which is connected so as to have a temperature compensation function. 2. An integrating sphere for diffusing incident laser light, a detector main body for detecting the laser light diffused by the integrating sphere, and a first thermocouple arranged substantially in the detector main body. And a detector main body for holding the detector main body and the second thermocouple, and a microlaser detector, and the microlaser detector is the detector main body. In a laser output control device having a case for holding a minute laser detector which holds so as to be positioned at the output port of the integrating sphere, a position where the second thermocouple in the minute laser detector can detect the ambient temperature. And a laser output control device in which the first thermocouple and the second thermocouple are connected in series so as to have a temperature compensation function by the interaction of these thermocouples.