JPH05138383A - Method for adjusting optical axis of laser beam machine - Google Patents

Abstract

PURPOSE:To improve the accuracy of optical axis adjustment by receiving the diffracted light past a slit with divided detectors, outputting this light as an electric signal group and making the optical axis adjustment by judging a mis-alignment direction from the breaking of the balance. CONSTITUTION:A laser beam 5 is passed through the rectangular slit 1 and is made into the diffracted light 6. This diffracted light 6 is received by the quadrisected detectors 2. The deviation in the optical axis is judged by using the difference signals of the detection signals from the right, left, upper, and lower light receiving elements of the detectors 2. This measuring means has a large change with the mis-alignment of the optical axis and the optical axis adjustment is executed with good accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus,
Particularly, it relates to a method of adjusting the laser optical axis.

[0002]

2. Description of the Related Art A typical method of adjusting the optical axis in a conventional laser processing apparatus is to place an object impermeable to laser light on the optical axis, such as a metal plate whose optical axis position is marked with marking lines. The mirrors are adjusted while visually observing the spots due to scattered light and fluorescent light generated on it, and they are aligned with the center of the marking line that displays the optical axis position.

Further, a circular hole having a diameter about the beam diameter of the laser light is placed at the position of the optical axis of the laser light, and the transmitted light from this hole is monitored to make an adjustment so that the value becomes maximum. The method of doing is also devised.

[0004]

Among the conventional optical axis adjusting methods, in the former case, the resolution is insufficient for a human to visually judge, and the indistinctness of the fluorescent coloring in the case of a laser beam which is not in the visible range, etc. Therefore, it is not an appropriate method when strict optical axis adjustment is required.

In the latter case, the rate of change is small when the optical axis of the signal due to the laser light passing through the circular hole is shifted, and it is difficult to determine that the optical axis center position is met. Had.

In view of the above-mentioned drawbacks, a technical object of the present invention is to provide an easy optical axis adjusting method for a laser processing apparatus.

[0007]

According to the present invention, a slit arranged as a target whose optical axis is to be confirmed, and diffracted light generated after passing through the slit are received, and right and left of the diffracted light after passing through the slit and The eccentric direction of the laser optical axis is determined based on the difference between the detector divided into two or more that outputs an electric signal group corresponding to the up-and-down balance and the electric signal group output from the detector, and the diffraction is performed. An optical axis adjusting method for a laser processing apparatus is provided, which has an adjusting means for adjusting the optical axis so that the left and right and up and down balance of light is maintained.

That is, in the optical axis adjusting method of the present invention, a rectangular slit plate is used as a target for confirming the optical axis, and the diffracted light generated by the rectangular slit is monitored by a two-division or four-division light receiving element, The optical axis deviation and its matching are determined by the balance of the light quantity in the left-right direction or the vertical direction. The measuring means has a large change rate with respect to the optical axis deviation, and the optical axis can be adjusted with high accuracy.

[0009]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a bird's eye view showing the configuration of an embodiment of the present invention. The size of the opening of the rectangular slit 1 placed on the optical axis 7 of the laser light 5 is about half the beam diameter of the laser light. The diffracted light 6 generated after passing through the rectangular slit is
The 4-divided detector 2 receives light, and the difference between the detection signals from the left and right light receiving elements is used to determine the deviation of the optical axis in the left and right direction and the up and down direction.

Although only the signal processing system in the horizontal direction is shown in the figure, the same processing is performed in the vertical direction. Since the laser light is axisymmetric with respect to the optical axis, the difference signal becomes zero only when the laser optical axis coincides with the center of the rectangular slit, and when there is a deviation in either direction, the intensity of the diffracted light generated on that side becomes stronger. An out-of-balance difference signal is generated. The 0th-order light that hits the center of the 4-split detector is cut by placing a light shield plate.

If the wavelength of the laser is 0.53 μm and the width of the opening of the rectangular slit is 0.5 mm, the direction in which the diffracted light is generated is about 0.09 ° in the case of the first order and the second order. In the case of, the direction is inclined by about 0.15 °. If the detector is placed 30 cm away from the rectangular slit, it will be 1
The distance between the second-order diffracted light and the detector light-receiving surface is about 0.94 mm.
, Which can be detected with sufficient separation.

FIG. 2 is a stylized diagram of a detector used in another embodiment of the present invention. In the first embodiment, each light receiving element of the four-divided detector is composed of a single light receiving surface, but in this embodiment, a detector array is used. The deviation of the optical axis is determined by providing an appropriate signal intensity as a threshold value and comparing the number of unit light receiving elements 21 that have reached the level of this threshold value.

[0014]

As described above, according to the present invention, the rectangular slit as a target for confirming the optical axis and the diffracted light generated by the rectangular slit are detected by the two-division or four-division detector, and the light quantity balance of the diffracted light is utilized. Since the method of measuring the deviation of the optical axis is adopted, there is an effect that this can be performed more accurately than the conventional optical axis adjusting method.

[Brief description of drawings]

FIG. 1 is an overhead view showing a configuration of a first embodiment of the present invention.

FIG. 2 is a schematic diagram of a detector used in the second embodiment.

[Explanation of symbols]

 1 rectangular slit 2 4 split detector 6 diffracted light

Claims (1)

[Claims] 1. A slit arranged as a target whose optical axis is to be confirmed, and a diffracted light generated after passing through the slit are received, and an electric power corresponding to a lateral or vertical imbalance of the diffracted light after passing through the slit is received. The eccentric direction of the laser optical axis is determined based on the difference between the detector that outputs the signal group and the electric signal group that is output from the detector, and the left, right, up, and down balance of the diffracted light is maintained. An optical axis adjusting method for a laser processing apparatus, comprising: an adjusting unit that adjusts the optical axis so as to sag.