JPH0231635B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a laser beam focusing device,
More specifically, a laser beam focusing device that can visually or automatically focus a condensing device on an object to be irradiated with a laser beam, which is a workpiece, when cutting a workpiece with a laser beam. It is related to.

[Prior art] Laser beams, especially carbon dioxide laser beams, have wavelengths that are
It is 10.6 μm and invisible to the naked eye. In addition, because of the strong force, it was difficult to determine the focal point position visually.

For this reason, for example, in laser processing equipment, the workpiece is irradiated with a laser beam once, and the size of the hole is checked.
I then repeated this operation several times until I found the smallest hole and manually adjusted the focus. Therefore, there were disadvantages in that it was time consuming and could not be matched accurately.

[Summary of the invention]

This invention was made to eliminate such drawbacks, and the output light of the laser oscillator and the reflected light from the object to be irradiated are transmitted from the laser beam transmission path between the laser oscillator and the object to be irradiated with the laser beam. It is an object of the present invention to provide a laser focusing device that adjusts a condensing device so that the ratio of the two is maximized.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a characteristic diagram showing the relationship between the deviation of the processing lens from the focal position and the output of the divider.

In FIG. 1, 1 is a laser oscillator, 2 is a transmission path for laser light, 3 is a bend mirror, 4 is a processing lens which is a condensing device, 5 is a workpiece, that is, an object to be irradiated with laser light, and 6 is a processing lens. 4, a beam splitter 7 is provided in the laser beam transmission path 2, and extracts a part of the output of the laser oscillator 1 and a part of the reflected light from the workpiece 5. . A first laser sensor 8 detects the laser output light reflected by the beam splitter 7.
A second laser sensor 9 detects the reflected light from the workpiece 5 reflected by the beam splitter 7.
10 is a divider that calculates the ratio c=a/b between the output b of the first laser sensor 8 and the output a of the second laser sensor 9; 11 is a meter that calculates the output c of the divider 10; It measures and displays it visually. 12 is a focus position determination device, and 13 is a servo circuit.

In the above configuration, when the workpiece 5 is irradiated with laser light, a portion of the laser light is reflected. At this time, when the processing lens 4 is moved up and down to focus on the workpiece 5, the reflected light becomes a parallel light beam and returns along the transmission path from which it came. If the focus is shifted, a part of the reflected light may not enter the processing lens 5, or it may be diverged even if it enters the processing lens 4, so that the reflected light output detected by the second laser sensor 9 will be It is at its maximum when it is in focus. Therefore, the relationship between the deviation of the processing lens 4 from the focal position and the output of the divider 10 has the characteristics shown in FIG.

From the above, when the position of the processing lens 4 is moved up and down with respect to the workpiece 5, the focal position of the processing lens 4 and the surface of the workpiece 5 coincide with each other when the value of the meter 11 reaches the maximum. It's time.

It has a mechanism for moving the processing lens 5 up and down by a drive device such as a motor 6, and a focus position determination device 12 and a servo circuit 13 so that the output of the divider 10 is maximized.
By assembling a servo mechanism with the lens, focusing can be performed automatically.

If a highly reflective material such as copper or aluminum is used and has the same thickness as the workpiece 5, the focal position can be clearly set.

For example, when cutting a thick workpiece 5, it is possible to cut more efficiently by focusing on a position slightly deeper than the surface. Even in this case, the focus can be set visually on the surface, and then, for example, how many mm should be lowered can be determined by calculation and the processed lens can be moved.

In addition, although the above-mentioned embodiment described the focusing of the laser processing apparatus, the same effect can be obtained by focusing the laser beam on the object to be irradiated.

〔Effect of the invention〕

As can be seen from the above description, according to the present invention, the laser oscillator is arranged in the transmission path of the laser beam, and when the output light of the laser oscillator and the output light irradiate the irradiated object, a part of it is reflected and transmitted. a beam splitter that takes out each part of the reflected light that has returned to the path; a first laser sensor that detects the output light taken out by the beam splitter; and a first laser sensor that detects the output light taken out by the beam splitter; 2nd to detect
A laser sensor is provided, and a computing unit that computes the ratio of the outputs of the first and second laser sensors and outputs the maximum value when the light condensing device is moved up and down to focus on the surface of the irradiated object. The simple structure has the following effects.

(1) Focus positioning can be performed accurately by visual inspection.

(2) By calculating the ratio of the outputs of the first and second laser sensors, the sensitivity remains constant even if the output of the laser oscillator changes.

(3) Automatic focusing is possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a characteristic diagram showing the relationship between the deviation of the processing lens from the focal position and the output of the divider. In the figure, 1 is a laser oscillator, 2 is a transmission line, 3 is a bend mirror, 4 is a processing lens (concentrator), 5 is a workpiece (irradiated object), 6 is a motor, 7 is a beam splitter, 8 is a first laser sensor, 9 is a second laser sensor, 10 is a divider, 11 is a meter, 12
1 is a focus position determination device, and 13 is a servo circuit.
Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A condensing device that is supported in a vertically movable manner and that condenses laser light transmitted from a laser oscillator via a transmission path onto an irradiated object; , a beam splitter that takes out each part of the output light of the laser oscillator and the reflected light that is partially reflected when the output light irradiates the irradiated object and returns through the transmission path; a first laser sensor that detects the output light taken out by the beam splitter; a second laser sensor that detects the reflected light taken out by the beam splitter; and a second laser sensor that detects the reflected light taken out by the beam splitter; A laser focusing device comprising: a calculator that calculates a ratio and outputs a maximum value when the light focusing device is moved up and down to focus on the surface of the irradiated object.