JPH04190991A - Laser beam machine - Google Patents

Abstract

PURPOSE:To observe a machining state in the direction of depth of a material to be machined which is at work in a real time by establishing an interference optics section in an observation optics system of a laser beam machine. CONSTITUTION:Illumination from an illuminating lamp 21 is changed by a polarizer 29 into a linear polarization and after the azimuth of this linear polarization is converted by a lambda/4 plate 31 into a desired azimuth, the illumination is made incident on a prism 28. The linear polarization which enters the prism 28 is divided into two beams in which oscillating surfaces are at right angle with each other and the material 15 to be machined is illuminated. The bisected laser beams are reflected by the material 15 to be machined, enter the prism 28 again and are joined as the oscillating directions are orthogonally crossed. An analyzer 30 is inserted into an observation optical path provided with a camera 25, takes out common oscillation components of the beam outgoing from the prism 28 to cause interference. An interference contrast is obtained by the material 15 to be machined and the material 15 to be machined can be observed cubically by an interference contrast image reflected to a surface state of the material 15 to be machined.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a laser processing device, and particularly to a laser processing device having features in an optical system.

[Conventional technology]

Conventional laser processing equipment, as shown in Figure 6,...
a laser oscillator 1, a gyroic mirror 2 that functions as a total reflection mirror for the laser beam and a half mirror for visible light, and an objective lens 4 that focuses the laser beam onto the workpiece 3; An illumination lamp 5 for illuminating the workpiece 3, an imaging lens 7 for focusing the reflected image from the workpiece 3 onto the light receiving surface of the camera (T~' camera or CCD camera) 6, and the illumination The structure includes a half mirror 8 for transmitting the illumination light from the lamp 5 and guiding the reflected image from the workpiece 3 to the camera 6. Note that a condenser lens 9 is arranged between the illumination lamp 5 and the half mirror 8.

The laser beam emitted from the laser oscillator 1 is reflected by the guichroic mirror 2, and is directed to the workpiece 3 by the objective lens 4.
The light is focused upwards. The processing point of the workpiece 3 during processing is imaged by the camera 6, and the processing point can be observed in real time on the TV monitor 10. Also, TV monitor 1
Since the magnification of o is known, the X of workpiece 3 after machining is
The machining width in the SY direction can be estimated.

[Problems to be Solved by the Invention] 1 However, although this conventional laser processing apparatus is equipped with an observation optical system, it is only possible to observe the surface using a bright field image. For this reason, when considering the processing of different two-layer films on a glass plate, if each film is processed at the same location with different beam diameters, the state of the film in the depth direction cannot be known during processing, and each There was a problem in that it was not clear what shape the film was processed into. Another problem is that in order to observe the cross-sectional shape of a processing point, it is necessary to cut the workpiece 3 and observe the cross-section.

SUMMARY OF THE INVENTION An object of the present invention has been made in view of the above-mentioned problems, and is to provide a laser processing apparatus that allows the condition of a workpiece in the depth direction to be observed on the spot during processing.

[Means to solve the problem]

The invention according to claim 1 provides a laser oscillator that oscillates a laser beam, a controller that supplies power to the laser oscillator and controls its operation, and an optical section that irradiates a workpiece with the laser beam emitted from the laser oscillator. In addition, a mounting table with a mechanism for holding the workpiece and moving the workpiece in the X and Y directions using a motor, and a controller that controls the operation of this mounting table are used to create an optical laser processing device. The section consists of an objective lens that focuses the laser beam onto the workpiece, an illumination optical section that consists of an illumination lamp and a condenser lens that illuminate the processing point on the workpiece, and an optical system that observes the laser processing status of the workpiece. The observation optical section includes an optical camera, an imaging lens, and a TV monitor, and an interference optical section that generates brightness and darkness contrast by interference depending on the surface condition of the workpiece.

The invention as claimed in claim 2 provides an interference optical section including a prism in which wedge-shaped polished crystals having birefringence that separate incident light into extraordinary rays and ordinary rays are joined together so that their optical axes are perpendicular to each other; This configuration includes a polarizer that can selectively extract linearly polarized light with a specific azimuth from among the polarization states of light, and an analyzer that detects the azimuth of the incident linearly polarized light.

In the invention of claim 3, the image of the workpiece during laser processing is passed through an interference optical section, the interference contrast image obtained from the interference optical section is sent to an image processing device, and the interference contrast image is processed by the image processing device. It is configured to process bright and dark level signals and feed this signal back to the laser oscillator.

[Effect]

As described above, according to the present invention, by providing an interference optical section in the observation optical system of a conventional laser processing device, the processing state in the depth direction of the workpiece being processed is made clear by the contrast of brightness and darkness caused by the interference. The image can be observed in real time on a digital monitor. in this way,
By obtaining a bright and dark contrast due to interference depending on the processing state in the depth direction of the workpiece, for example, when selectively processing each film in a multilayer film, it is possible to process three layers in a non-contact state without destroying the workpiece. Dimensional machining conditions can be observed on the spot.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a laser processing apparatus according to the present invention. The laser oscillator 11 that oscillates and emits laser light is configured such that a laser oscillator controller power supply 12 supplies power to the laser oscillator 11 and controls its operation. Further, the laser beam emitted from the laser oscillator 11 is guided to the optical section 13, and the laser beam emitted from the optical section 13 is focused onto the workpiece 15 fixed on the mounting table 14. There is. This mounting table 1
4 is directly connected to a motor 17 via a ball screw 16, and the mounting table 14 can be moved in a linear direction under the control of a motor controller 18. Thereby, the workpiece 15 fixed on the mounting table 14 can be processed into a straight line.

FIG. 2 is a block diagram of the configuration of the optical section 13.

The laser beam emitted from the laser oscillator 11 is reflected by the guichroic mirror 19, which totally reflects the laser beam and transmits visible light, and passes through the objective lens 20 onto the workpiece 15. The light is focused.

Illumination light from the illumination lamp 21 is condensed by a condenser lens 22, reflected by a half mirror 23, and directed toward the workpiece 1.
5 Illuminated upwards. The reflected image from this workpiece 15 is
It passes through the half mirror 23 and is imaged by the imaging lens 24 onto the light-receiving surface of a camera (TV camera or CCD camera) 25, and the processing state of the workpiece 15 is observed on the TV monitor 26 connected to the camera 25. It is now possible. 1 The interference optics section 27 is a prism formed into parallel planes by joining wedge-shaped polished crystals that have birefringence, which separates light into extraordinary and ordinary rays when incident, so that their optical axes are perpendicular to each other. 28, a polarizer 29 that can selectively take out linearly polarized light with a specific azimuth among the polarization states, and an analyzer 30 that detects the azimuth of the incident linearly polarized light. The illumination light from the illumination lamp 21 becomes linearly polarized light with a specific azimuth angle by the polarizer 29,
After converting the azimuth of the linearly polarized light into a desired azimuth using the four plates 31, the linearly polarized light is made incident on the prism 28.

The linearly polarized light incident on the prism 28 is separated into two lights whose vibration planes are perpendicular to each other, and illuminate the workpiece 15.

The split light is reflected by the workpiece 15, enters the prism 28 again, and is combined with the vibration directions perpendicular to each other. The analyzer 30 is inserted into the observation optical path where the camera 25 is arranged, and extracts a common vibrational component of the light emitted from the prism 28 to cause interference.

As shown in FIG. 3, the workpiece 15 has a portion 15a thereof.
If it protrudes convexly by a height h, the wavefront W of the incident light
becomes a wavefront where the convex portion 15a has advanced by 2h, and the incident light is split into two lights whose wavefronts are slightly shifted laterally.

FIG. 4 shows the change in optical thickness when the workpiece 15 is irradiated with light. Let the phase difference between the regions C1 and C7 of the workpiece 15 be δ1 and C2, respectively, and the amount of lateral shift of the incident light wavefront W be Δ. The two slightly laterally shifted wavefronts produce phase differences of δ1 and C2, respectively, in regions CI and C2 of the workpiece 15 where the optical thickness changes as shown in FIG. In regions A and B of the workpiece 15, there is no phase difference between the two wavefronts, so no brightness contrast of the interference color due to interference can be obtained.
, δ, resulting in brightness and darkness contrast due to interference, which depends on C5 and C2. The phase difference δ1 and C2 are respectively δ1 = △(aW/cJX),
, C2=Δ(a W/a X )2. δW/δX is the wavefront W (7)? @ differential coefficient, and the phase difference changes due to the change in this differential coefficient, and the workpiece 15
An interference contrast is obtained at the C+ and C2 portions, and the workpiece 15 can be observed three-dimensionally by the interference contrast image reflected on the surface condition of the workpiece 15.

FIG. 5 is a block diagram showing a second embodiment of the present invention. In this example, the workpiece 1 during laser processing
The interference contrast image obtained from the interference optical unit 27 is sent to the image processing device 32, and the interference contrast image is processed into bright and dark level signals by the image processing device 32. This signal is then fed back to the laser oscillator 11 via the signal line 33. In the laser processing apparatus having such a structure, the brightness level signal of the interference contrast image fed back to the laser oscillator 11 is controlled. As a result, the processing state of the workpiece 15 can be controlled three-dimensionally.The other configurations such as the microscopic mirror 19, the objective lens 20, and the camera 25 are the same as in the first embodiment described above. Therefore, its explanation will be omitted.

〔Effect of the invention〕

As explained above, according to the laser processing apparatus according to the present invention, since the observation optical system of the conventional laser processing apparatus is configured to include an interference optical section, it is possible to perform processing in the depth direction of the workpiece being processed. The state is made clear by the contrast between light and dark caused by interference, and the image can be observed in real time on a TV monitor. In this way, it is possible to obtain a bright and dark contrast by interference depending on the processing condition in the depth direction of the workpiece, so that, for example, when selectively processing each film in a multilayer film, it is possible to do so without destroying the workpiece. The effect is that the three-dimensional processing state can be observed on the spot in a contact state.

Further, as in the invention of claim 3, by sending an image of brightness and darkness contrast due to interference according to the uneven state of the workpiece to the image processing device, and feeding back the signal from there to the laser processing device, The machining state of the workpiece can be controlled three-dimensionally, and a stable machining state can always be obtained.

From the above, by in-situ observation of the workpiece being processed, it is possible to shorten the processing time including evaluation compared to the conventional method, and it has the effect of improving the operating rate of the equipment. .

[Brief explanation of the drawing]

FIG. 1 is a configuration block diagram showing an embodiment of a laser processing device according to the present invention, FIG. 2 is a configuration block diagram of an optical section,
FIG. 3 is a configuration diagram of the workpiece, FIG. 4 is a configuration diagram of the workpiece with respect to changes in optical thickness, and FIG. 5 is a configuration block diagram showing another embodiment of the laser processing apparatus according to the present invention. , 6th
The figure is a configuration block diagram showing an example of a conventional laser processing device. 11... Laser oscillator, 12... Laser oscillator controller power supply, 13
...Optical section, 14... Mounting table, 15... Workpiece, 18... Motor controller, 19...
- Gicroic mirror, 20... Objective lens, 21... Illumination lamp, 22... Condenser lens, 24... Imaging lens, 25... ... Camera, 26 ... TV monitor, 27 ... Interference optics section, 28 ... Prism, 29 ... Polarizer, 30 ... ...Analyzer, 32...Image processing device.

Claims (1)

[Claims] 1. A laser oscillator that oscillates a laser beam, a controller that supplies power to the laser oscillator and controls its operation, and an optical system that irradiates a workpiece with the laser beam emitted from the laser oscillator. In the laser processing apparatus, the laser processing apparatus includes a part, a mounting table having a mechanism for holding a workpiece and moving the workpiece in X and Y directions by a motor, and a controller for controlling the operation of the mounting table. The system includes an illumination optical section consisting of an objective lens that focuses the laser beam onto the workpiece, an illumination lamp and a condenser lens that illuminates the processing point on the workpiece, and an optical system that observes the laser processing state of the workpiece. A laser processing device characterized by being equipped with an observation optical section consisting of an optical camera, an imaging lens, and a TV monitor, and an interference optical section that generates brightness and darkness contrast by interference depending on the surface condition of a workpiece. . 2. The interference optics section consists of a prism in which wedge-shaped polished crystals with birefringence, which separate light into extraordinary and ordinary rays when incident, are joined together so that the optical axes are perpendicular to each other, and a prism that separates the light into extraordinary and ordinary rays. 2. The laser processing apparatus according to claim 1, comprising: a polarizer capable of selectively extracting linearly polarized light having a specific azimuth; and an analyzer detecting the azimuth of the incident linearly polarized light. 3. The image of the workpiece during laser processing is passed through an interference optics section, and the interference contrast image obtained from this interference optics section is sent to an image processing device, which processes the interference contrast image into bright and dark level signals. , and is configured to feed back this signal to a laser oscillator.