JPS60170987A - Optical sensor for laser - Google Patents

Abstract

PURPOSE:To detect the deterioration of optical members constituting a laser device by a method wherein a detecting mechanism is provided, outside the path of the laser beam, constituted of a light source to throw light upon the optical members and a means to detect scattered reflection. CONSTITUTION:Deterioration of a partially reflective mirror 2 for a laser beam 3, 4 is principally attributable to faults in coatings 21, 22. With such faults being scarcely uniform in directivity, the scattering of light is related largely as the cause of the faults. The light emitted by a light source 30 is scattered due to faults in the coatings 21, 22. The scattered light is detected by a detecting means 31 installed in the vicinity of the light source 30. The detecting means 31 is connected to an alarm means 40 outputting a warning upon detecting a value exceeding a prescribed level. The alarming means 40 thus annunciates any deterioration of faults in the mirror 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a laser optical sensor, and particularly to a sensor for detecting in advance the usage limit of a laser optical member.

[Prior art]

FIG. 1 is a schematic configuration diagram showing a conventional laser processing apparatus.

In the figure, +11. (21 is a total reflection mirror and a partial reflection mirror, respectively, which constitute the laser resonator (8). (3) is an internal standing wave beam of the laser beam.

(4) is a laser beam, (5) is a pender mirror that reflects the laser beam (4), and (6) is a lens that allows the laser beam (4) to pass through.

(7) is the workpiece.

A laser beam (4) is emitted from a laser resonator (8) constituted by a partial reflection mirror (2) and a total reflection mirror (1), and is bent by a pendulum mirror (5) and then passed through a lens (6). ) is focused on the 7JII work object (7) and this is exposed.

Since the partial reflection mirror (2) and the total reflection mirror (1) are constantly hit by the internal standing wave beam (3), which has an intensity several times stronger than the output beam, their surfaces are easily deteriorated and damaged. Therefore, with a normal 1KW class CO2 laser.

This had to be cleaned or replaced after several hundred hours of operation.

Further, the lens (6) is susceptible to surface stains and damage due to sputtering of the workpiece (7).

Sometimes they break down after hundreds of hours of operation. If the working environment of the pendamor mirror (5) is poor, the attached dust and the like will burn onto the surface and accelerate deterioration.

Since the conventional laser device has a fire path configured as described above, the lifespan of laser optical components such as mirrors is limited.

is short.

Further, since there is no effective means for predicting deterioration of laser optical members, there is a problem in that a device using a laser suddenly becomes unusable during operation.

[Summary of the invention]

The present invention was made in order to eliminate the drawbacks of the conventional ones as described above, and includes a light source that irradiates light from outside the oscillation optical path of the laser beam toward the surface of an optical member for a shear laser; By equipping the laser device with a laser optical sensor equipped with a detection mechanism that detects scattered light scattered on the surface of the component, it is possible to detect deterioration of the laser optical component in advance and determine when it is time to replace or clean the mirror, etc. It is an object of the present invention to provide a laser optical sensor that can be set appropriately by a user.

[Embodiments of the invention]

The inventors thoroughly analyzed the characteristics of optical members for lasers such as mirrors that were deteriorated or damaged in many cases. As a result, they discovered that deteriorated or damaged mirrors scatter a lot of light from the light source. Based on this discovery, the inventors.

The present invention aims to provide a device that can predict deterioration and damage to a laser optical member by detecting scattered light.

An example of this discovery will be shown below. FIG. 2 is a partial cross-sectional configuration diagram when a laser optical sensor according to an embodiment of the present invention is installed on a partially reflecting mirror (2) of a C02 laser device.

In Figure 2, (21 is a mirror support body, and the inner surface of the normal partially reflective mirror (2) is coated with a partially reflective film Qυ, and the outer surface is coated with an AR film (anti-reflection film).
(to) is installed on the mirror support (a), and is a light source that irradiates light out of the oscillation optical path of the laser beam and toward the surface of a laser optical member such as a mirror, such as a semiconductor laser, a light emitting diode, or a white light source; Here, a semiconductor laser was used. 0
υ is a detection mechanism that detects the scattered light scattered on the surface of a laser optical member such as a partial reflection mirror (2), 03 is a condensing lens provided in front of the detection mechanism Gυ, and (to) is a detection mechanism that The filter for separation, θl, is an alarm mechanism.

Note that the detection mechanism 6υ is an Fi photodiode.

It can be translated as bolometer, pyroelectric element, photomultiplier (photomultiplier tube), etc. Here, a photodiode was used.

Deterioration of the partially reflecting mirror (2) mainly occurs due to defects in the coated film material 0D03. Since defects have almost no directionality, scattered light generally has a large causal relationship with defects. The light emitted from the light source (7) is
It is scattered by defects in the membrane material QυQ. This scattered light is detected by a detection mechanism 0υ installed near the light source.

An alarm mechanism (by connecting to 4G) that outputs an alarm when the detection level of the detection mechanism c3Il exceeds a predetermined value, the user will know the degree of deterioration and damage of the mirror (2).

Note that the condenser lens 03. in the above embodiment. The filter may or may not be used as appropriate in relation to the wavelength 2 intensity of the light from the light source and the wavelength 1 intensity of the light from the atmosphere.

In addition, although the above embodiment shows an example in which it is applied to the partial reflection mirror (2), other mirrors (11 (51) and lenses (
It goes without saying that the present invention can be applied to optical members for lasers such as 6). 54.Furthermore, although an alarm mechanism is provided in the above embodiment, the alarm mechanism may not be provided and the user may appropriately set the timing for replacing or cleaning the mirror etc. using a meter with a detection mechanism of 0υ.

Further, the present invention is particularly effective for YAG laser + "co2 laser, etc., which are destined to operate in non-city visible light and in relatively unclean conditions.

〔Effect of the invention〕

As described above, the present invention includes a light source that irradiates light from outside the oscillation optical path of the laser beam toward the surface of the shear laser optical member, and detects scattered light scattered on the surface of the laser optical member. Since a laser optical sensor equipped with a detection mechanism is provided in the laser device, it is possible to predict the lifespan of laser optical members such as mirrors in advance, and the ease of use of the laser device can be greatly improved.

[Brief explanation of the drawing]

Figure 1 is a schematic configuration diagram showing a conventional laser processing device, Figure 2
The figure is a partial cross-sectional configuration diagram showing a laser optical sensor according to an embodiment of the present invention. ftl, (21...mirror, +31. +41・
...laser light, (8)..., laser oscillator, (to)...
・Light source, 0υ...detection mechanism. Note that in the two figures, the same reference numerals indicate the same or equivalent parts. Agent Masuo Oiwa Figure 1 Figure 2

Claims (1)

[Claims] (11. A light source that irradiates light toward the surface of the laser optical member; and a detection system that detects scattered light scattered on the surface of the laser optical member. Laser optical sensor equipped with a mechanical cavity. (2) The laser optical sensor according to claim 1, wherein the laser optical member is a mirror constituting a laser resonator.