JP3003731B2 - Optical axis adjustment method for laser processing equipment - Google Patents

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,
In particular, the present invention relates to a method for adjusting the laser optical axis.

[0002]

2. Description of the Related Art Conventionally, a typical method of adjusting an optical axis in a laser processing apparatus is to place an object that is opaque to laser light on the optical axis, such as a metal plate in which the position of the optical axis is marked with a marking line or the like. The mirrors are adjusted while visually checking the spot caused by scattered light or fluorescent light generated thereon, and the optical axis position is adjusted to the center of the marking line for displaying the optical axis position.

[0003] Further, a circular hole having a diameter of about the laser beam diameter is placed at the position of the optical axis of the laser light, and the transmitted light from this hole is monitored and adjusted so that the value becomes maximum. A method of doing so has also been devised.

[0004]

Among the conventional optical axis adjusting methods, the former method has a problem in that the resolution is insufficient for a human to make a visual judgment, and the unclearness of the fluorescent color in the case of laser light that is not in the visible region. Therefore, it is not an appropriate method when strict optical axis adjustment is required.

[0005] In the latter case, the rate of change when the optical axis of the signal by the laser beam transmitted through the circular hole is shifted is small, and it is difficult to judge that the signal coincides with the optical axis center position. Had.

Accordingly, it is an object of the present invention to provide a method of adjusting an optical axis of a laser processing apparatus which is easy in view of the above-mentioned drawbacks.

[0007]

According to the present invention, there is provided a plate having a slit disposed as a target for confirming the optical axis of a laser beam of a laser processing apparatus; and a plate generated when the laser beam passes through the slit. And at least one pair of light receiving elements for receiving at least one pair of electric signals, and when the optical axis of the laser light coincides with the center of the slit, there is a difference between the at least one pair of electric signals. The difference between the at least one pair of electric signals becomes zero without generation, and the difference is generated between the at least one pair of electric signals when the optical axis of the laser beam is off the center of the slit. Adjustment of the optical axis of the laser light with respect to the plate having the slit,
An optical axis adjusting method for a laser processing apparatus, wherein the method is performed so that a difference between the at least one pair of electric signals output from the at least one pair of light receiving elements of the detector becomes zero.

That is, according to the optical axis adjusting method of the present invention, a rectangular slit plate is used as a target whose optical axis is to be confirmed, and the diffracted light generated by the rectangular slit is monitored by a two-divided or four-divided light receiving element. The optical axis deviation and its coincidence are determined based on the balance of the amount of light in the horizontal or vertical direction, and it is a measuring means having a large change rate with respect to the optical axis deviation, so that the optical axis can be adjusted with high accuracy.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an overhead 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 deviation of the optical axis in the left-right direction and the up-down direction is determined using the difference signal between the detection signals received by the four-segment detector 2 and from the left-right and up-down light-receiving elements.

Although only a left-right direction signal processing system is shown in the figure, the same processing is performed in the up-down direction. Since the laser light is axially symmetric with respect to the optical axis, the difference signal is zero only when the laser optical axis coincides with the center of the rectangular slit, and if there is any deviation, the intensity of the diffracted light generated on that side increases. The balance is lost and a difference signal is generated. The 0-order light hitting the center of the 4-split detector is cut by placing a light-shielding plate.

Assuming that 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 first order with respect to the optical axis, In this case, the direction is inclined by about 0.15 °. When the detector is placed 30cm away from the rectangular slit, the left, right, up and down
The distance at the detector light receiving surface between the next diffraction lights is about 0.94mm
Which can be sufficiently separated and detected.

FIG. 2 is a schematic 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 constituted by a single light receiving surface, but in this embodiment, a detector array is used. An appropriate signal strength is provided as a threshold, and the deviation of the optical axis is determined by comparing the number of the unit light receiving elements 21 reaching the threshold level.

[0014]

As described above, according to the present invention, a rectangular slit as a target for checking the optical axis and the diffracted light generated by the rectangular slit are detected by a two- or four-divided detector, and the light amount 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 with higher accuracy than the conventional optical axis adjustment method.

[Brief description of the 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 a second embodiment.

[Explanation of symbols]

 Reference Signs List 1 rectangular slit 2 quadrant detector 6 diffracted light

Claims (1)

(57) [Claims] A plate having a slit disposed as a target for checking an optical axis of a laser beam of a laser processing apparatus; and a plate receiving at least a pair of electric lights by receiving diffracted light generated when the laser beam passes through the slit. The at least one pair of electric signals is formed without generating a difference between the at least one pair of electric signals when the optical axis of the laser light is aligned with the center of the slit. When the optical axis of the laser beam is deviated from the center of the slit, and a detector arranged so that a difference occurs in the at least one pair of electric signals; The adjustment of the optical axis of the laser light with respect to the plate having the difference between the at least one pair of electric signals output from the at least one pair of light receiving elements of the detector is zero. So as, the optical axis adjusting method of a laser machining apparatus and performs.