JPH0781828B2 - Laser position detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a laser position detecting device for detecting the optical path position of a high-power laser beam using a plurality of thermocouples.

(Prior Art) In general, the path of a laser beam emitted from a laser oscillator changes subtly due to the influence of ambient thermal conditions or vibrations.

Therefore, when processing is performed using laser light, it is necessary to accurately detect the position of the optical path, and further it is necessary to perform optical path alignment that guides the laser light to the required optical path in the processing machine.

It is necessary to detect the position of the optical path to align the optical path,
As a conventional method for detecting the optical path position, in the case of a carbon dioxide laser, an acrylic plate or the like is irradiated with laser light, and determination is made by the burn mark (burn pattern).

(Problems to be Solved by the Invention) However, the above-mentioned conventional methods have problems that harmful fumes are generated and that operation takes time.

There is also a method of using a position detection sensor, but it cannot be used depending on the measurement wavelength, and when the laser light has a large output of kw class, the capacity of the sensor becomes a problem, so for a large output, long wavelength laser light. There was no suitable laser position detector available.

There is also a method of detecting the position of the laser beam using a profile sensor, but there are problems that it is expensive, and that absolute position detection is difficult and measurement accuracy is unstable.

An object of the present invention is to provide an inexpensive and easy-to-use laser position detecting device that can relatively easily detect the position of a large output laser beam.

[Structure of Invention]

(Means and Actions for Solving Problems) In the present invention, a hole through which laser light passes is provided in the central portion, a plurality of thermocouples are arranged at equal intervals around the hole, and these thermocouples are arranged at the center of the hole. The laser light is scanned by moving the laser light simultaneously in the direction of the arrow, and the calculation is performed based on the detection signal from the temperature increase of the thermocouple due to the laser light to detect the optical path position of the laser light.

(Example) An example of the present invention is shown in FIG.

In FIG. 1, four thermocouples 3 are respectively arranged in the vertical and horizontal directions in a thermocouple cover 6 toward the center of a hole of a base 1 having a hole 2 through which laser light passes.

The thermocouple covers 6 are respectively coupled to the stays 10 fixed on the base 1 via the pressing springs 9 and can be slid toward the center of the hole 2 by being guided by the thermocouple cover guide 7.

A disk 4 having as many oblique guide windows 8 as the number of thermocouples 3 is held on the base 1 by a plurality of disk guides 5 and can be rotated concentrically with the hole 2 of the base.

That is, the pin 11 corresponding to the guide window 8 is provided on the thermocouple cover 6.
When the disc 4 rotates, the pin 11 radially pushes up or pushes down the thermocouple 3 along the side surface of the guide window 8.

The rotation of the disc 4 is performed by moving a force receiver 12 fixed to the disc 4 by a motor 15 via a ball screw 13.

Further, in order to improve the positioning accuracy of the thermocouple cover 6, a pressing spring 9 is connected to each of the stays 10 fixed to the base 1 and is constantly pressed toward the center.

FIG. 2 shows a control device 21 for controlling the position detection sensor 20 configured as described above, which includes a driver for driving the motor 15, a converter for converting a signal from the thermocouple 3 into a distance, and a position. Has an arithmetic unit for calculating the optical path position of the laser light 22.

That is, the motor 15 is driven by a command from the control device 21, the disc 4 is rotated through the ball screw 13 and the force receiver 12, and the thermocouple cover 6 is moved in the radial direction through the guide window 8 and the pin 11. This allows 4 thermocouples 3
From the most retracted position, move forward toward the center at the same time.

Positions a to d of the thermocouples 3 when the signal levels from the four thermocouples 3 reach predetermined signal levels A are detected and stored by the encoder 16 coupled to the motor 15, and the positions a to When the detection of d is completed, the thermocouple 3 stops moving forward,
Return to the most retracted position.

Next, the base 1 of the laser beam 22 is obtained from the obtained position information a to d.
Deviation from the center of and Is calculated, and the optical path position of the laser light is detected.

FIG. 4 is a flow chart showing the above detection operation.

〔The invention's effect〕

As described above, according to the present invention, it is possible to accurately detect the optical path position of a high-power laser beam, which has been difficult in the past, by using a simple configuration, and thereby inexpensive, highly accurate, and in real time. A compact laser position detector that operates can be realized.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the entire arrangement thereof, FIG. 3 is a diagram showing an example of detection signals in the present invention, and FIG. 4 is a detection procedure in the present invention. It is a flowchart which shows an example. 1 ... Base, 2 ... Hole 3 ... Thermocouple, 4 ... Disc 5 ... Disc guide, 6 ... Thermocouple cover 7 ... Thermocouple cover guide, 8 ... Guide window 9 ... Push Spring, 10,14 ... Stay 11 ... Pin, 12 ... Force receiving 13 ... Ball screw, 15 ... Motor 16 ... Encoder, 20 ... Position detection sensor 21 ... Control device, 22 ... Laser light

Claims (1)

[Claims] 1. A base having a hole through which laser light passes,
A circle arranged on the base and rotated by a motor fixed on the base and having a hole concentric with the hole of the base and a respective guide window for moving the plurality of thermocouple covers toward the center of the hole. Plates, a plurality of thermocouples provided at the tip of the hole side of each thermocouple cover and detecting the intensity of the laser light that crosses the plate, and detection corresponding to the moving position in the center direction of each thermocouple. A laser position detecting device comprising an arithmetic circuit for calculating a center position of an optical path of laser light from a signal.