JP2001150162A - Method of laser beam machining for ceramic material and machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of a machining of ceramic material by which method a strain is given without causing a crack even when a defect exists inside. SOLUTION: In the machining method where a strain is given by irradiating a ceramic plate 11 with a pulsed laser beam emitted from a YAG pulse laser beam oscillator 10, a pulsed laser beam having a smaller cross section compared to the cross section of the ceramic plate is radiated several times upon over the whole area of the irradiated zone of the ceramic plate thus a crack generation of the ceramic plate is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing method and a processing apparatus for applying distortion to a ceramic plate using a laser beam.

[0002]

2. Description of the Related Art There is a demand for a process for generating a controlled strain in a ceramic material, particularly a ceramic thin plate having a side of several mm to several tens mm. As a specific example, the processing is such that a ceramic thin plate is distorted into a convex shape. Laser irradiation processing has been proposed as one of such processing methods. There are also two types of laser irradiation processing. In the first method, a part of the surface of the ceramic thin plate is removed (cut) by a laser beam focused sufficiently smaller than the area of the ceramic thin plate to generate a compressive stress. This causes distortion. In the second method, a laser beam having a cross-sectional area substantially equal to the area of the ceramic thin plate is irradiated to generate a scorch on the surface of the ceramic thin plate to generate a tensile stress, thereby causing distortion.

[0003]

However, the first method described above has a problem that dust is generated due to surface removal. On the other hand, the above-mentioned second method has a drawback that if a defective portion exists inside the ceramic thin plate due to irradiation of a large area, the probability of applying stress to the defective portion increases, and cracks occur. This is due to the fact that the ceramic thin plate is brittle because it is a brittle material, and it is unavoidable that there is a certain probability of having a defective portion therein. Therefore,
In the above-mentioned second method, cracks occur at a probability determined by the above-mentioned certain probability, and it is inevitable that the yield is restricted.

It is an object of the present invention to provide a method and an apparatus for processing a ceramic material capable of giving a strain without generating a crack even when a defect portion is present inside. is there.

[0005]

According to the present invention, there is provided a processing method for irradiating a ceramic plate with pulsed laser light from a laser oscillator to apply distortion, wherein the pulse having a smaller cross-sectional area than the area of the ceramic plate is provided. By irradiating the laser beam a plurality of times so as to cover the entire irradiation area of the ceramic plate, cracks in the ceramic plate are prevented.

In this processing method, the pulsed laser light has a square or linear cross section, and the pulsed laser light having the square or linear cross section is swung by a galvano scanner. A plurality of irradiations are performed over the entire irradiation area of the ceramic plate.

A processing apparatus according to the present invention comprises a pulsed laser oscillator, mask means for defining a cross-sectional shape of a pulsed laser beam emitted from the pulsed laser oscillator, and the pulsed laser beam passing through the mask means. A galvano scanner for oscillating the laser light, and an imaging lens for imaging the pulsed laser light oscillated by the galvano scanner on a ceramic plate mounted on a stage, wherein the mask means The cross-sectional area of the pulsed laser light is for making the cross-sectional area smaller than the area of the ceramic plate, the galvano scanner, the pulsed laser light having the small cross-sectional area, Irradiation is performed a plurality of times so as to cover the entire irradiation region.

In this processing apparatus, a collimation lens is disposed between the galvano scanner and the imaging lens.

In the present processing apparatus, a uniform optical system is provided between the laser oscillator and the mask means for equalizing the energy intensity in the cross-sectional area of the pulsed laser light from the laser oscillator. .

In the present processing apparatus, the stage is movable in the X-axis direction and the Y-axis direction, and a plurality of the ceramic plates are mounted on the stage.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the background of the present invention will be described. In the second method described above, since laser irradiation is performed in a large area in which laser irradiation is performed on almost the entire surface at one time, the probability that stress is applied to a defect existing inside the ceramic plate increases, and cracks occur. It is easy to occur. In addition, the larger the irradiation area, the greater the internal stress in the central portion of the ceramic plate, so that cracks are likely to occur.

Therefore, in the present invention, the cross-sectional area of the laser beam applied to the ceramic plate is reduced to reduce the amount of heat input by one irradiation, and the irradiation of this small area is performed over the entire irradiation area of the ceramic plate. Is performed a plurality of times.

Next, an embodiment of a laser processing apparatus according to the present invention will be described with reference to FIG. The laser processing apparatus according to the present embodiment is a processing apparatus that applies a pulsed laser beam from a YAG pulsed laser oscillator 10 to a ceramic plate 11 to apply distortion, and a pulsed laser beam having a small cross-sectional area is output by a galvano scanner 13. Ceramic plate 1
Irradiation is performed a plurality of times so as to cover the irradiation area 1 in this case, almost over the entire area, thereby giving distortion. A plurality of ceramic plates 11 are arranged in a row on a stage 12 movable in the X-axis direction and the Y-axis direction.

On the emission side of the YAG pulse laser oscillator 10, there is arranged a uniform optical system 18 for making the energy intensity in the sectional area of the pulsed laser light uniform. When the YAG pulse laser oscillator 10 is used, the uniform optical system 18 can be realized by an optical fiber. That is, the YAG laser light can be transmitted by an optical fiber, and the optical fiber has an effect of making the intensity distribution of the laser light transmitted therethrough uniform. In addition, the uniform optical system 18 can be realized by another well-known optical system, for example, a so-called kaleidoscope.

The pulsed laser light that has exited the uniform optical system 18 is shaped by the mask 14 into a cross-sectional area smaller than the area of the ceramic plate 11. Its shape is
As will be described later, the shape is rectangular or linear.

The galvano scanner 13 oscillates a pulsed laser beam having a small cross-sectional area shaped by a mask 14 and irradiates the laser beam a plurality of times so as to cover almost the entire surface of the ceramic plate 11. As is well known, the galvano scanner 13 is a so-called galvano mirror in which a reflecting mirror is attached to a rotary drive shaft driven by a motor.
Here, a two-axis type galvano scanner is used in which a pulsed laser beam can be swung on the stage 12 in the X-axis direction and the Y-axis direction perpendicular thereto by combining two galvanometer mirrors. In FIG. 1, only one galvanomirror is symbolically shown.

On the reflection side of the galvano scanner 13, a collimation lens 17 is arranged. The collimation lens 17 is for making pulsed laser light obliquely incident from the galvano scanner 13 parallel to the optical axis of the collimation lens 17. This is because the pulsed laser light is swung in various angular directions by the galvano scanner 13, so that the pulsed laser light that is farther from the optical axis of the collimation lens 17 is farther from the optical axis. For this reason, the collimation lens 17
It has a diameter large enough to cover the scanning range of the galvano scanner 13.

The collimation lens 17 and the stage 12
Between them, image forming lenses 15 and 16 for forming an image of the pulsed laser light having a pattern defined by the mask 14 so as to focus on the ceramic plate 11 are arranged. The imaging lenses 15 and 16 can arbitrarily select a reduction ratio of the pattern defined by the mask 14 on the ceramic plate 11 by selecting their focal lengths.

The reflection mirrors 21 and 2
An optical path from the YAG pulse laser oscillator 10 to the stage 12 is formed by interposing 2, 23 and 24. In FIG. 1, the pulsed laser light from the collimation lens 17 is drawn so as to deviate from the reflection mirror 22, but this is because the optical path of the pulsed laser light from the collimation lens 17 is enlarged. . Actually, the scanning range of the galvano scanner 13 is an area of about several cm, and the reflection mirror 22 can sufficiently cope with the change in the incident position of the pulsed laser light.

In this embodiment, a damper 25 is arranged at a position off the collimation lens 17. The damper 25 is for irradiating pulsed laser light to the stage 12 while pulsed laser light irradiation is not performed, and a cooling means such as water cooling is provided to prevent heat generation due to pulsed laser light irradiation. Have been. The reason for using such a damper 25 will be described later.

Further, a reflection mirror 24 that transmits visible light is used, and an observation optical system 27 is disposed above the reflection mirror 24 via a reflection mirror 26. Usually, a CCD camera is used for the observation optical system 27, and the ceramic plate 1 being processed is used.
1 is used for observation and the positioning operation of the stage 12. The reflection mirror 24 transmits a very small part of the pulsed laser light, and the energy monitor 28 is disposed on the transmission side. Energy monitor 28
Monitors the energy value of each pulsed laser beam incident thereon. This monitoring result is sent to, for example, a control device (not shown) of the present processing apparatus, and when there is an abnormality such as an energy value being too low, the pulsed laser light is again applied to the same area of the ceramic plate 11. Can be controlled. Alternatively, if the above control is not performed even if there is an abnormality as described above, there is a possibility that a processing defect may occur in the ceramic plate 11 irradiated with the pulsed laser beam having a low energy value. Can be notified.

The processing operation of the processing apparatus having the above configuration will be described. The pulsed laser light from the continuously oscillating YAG pulse laser oscillator 10 is made to have a uniform energy intensity with respect to its cross-sectional area by the uniform optical system 18 via the reflection mirror 21. The pulsed laser light that has exited the uniform optical system 18 is shaped by the mask 14 into a pulsed laser light having a small area. The pulsed laser light having this small area is oscillated by the galvano scanner 13 and further converted into a pulsed laser light parallel to the optical axis by the collimation lens 17. This pulsed laser light enters the imaging lens 15 via the reflection mirrors 22 and 23. The pulsed laser light that has passed through the imaging lens 15 passes through the reflection mirror 24 and is applied to a predetermined position of the ceramic plate 11 at a predetermined reduction ratio through the imaging lens 16.

In particular, the scanning operation by the galvano scanner 13 irradiates the pulsed laser light having a small area a plurality of times so as to cover almost the entire surface of one specific ceramic plate 11 on the stage 12. During this time, the stage 12 does not move.

FIG. 2 shows that the mask 14 is used to irradiate the entire surface of the ceramic plate 11 with a pulsed laser beam shaped into a pulsed laser beam having a rectangular cross-sectional area sufficiently smaller than the area of the ceramic plate 11. The irradiation pattern in the case is shown. The galvano scanner 13 can irradiate the entire surface of the ceramic plate 11 by oscillating and irradiating the ceramic plate 11 with a pulsed laser beam having a rectangular cross-sectional area in the order indicated by the arrow in FIG. . Of course, this irradiation pattern can be formed into any shape by controlling the scanning of the galvanomirror 13.

When the entire surface of the ceramic plate 11 is irradiated with the pulsed laser light a plurality of times, the stage 1
2 is moved so that the next ceramic plate 11 comes to the irradiation area of the pulsed laser beam, that is, the scan area of the galvano scanner 13.

The galvano scanner 13 emits pulsed laser light toward the damper 25 during the movement of the stage 12. On the other hand, during processing, the YAG pulse laser oscillator 10 is kept oscillating. YA
The reason why the G-pulse laser oscillator 10 keeps oscillating is to secure the energy stability of the pulsed laser light. That is, if the oscillation of the YAG pulse laser oscillator 10 is stopped during the movement of the stage 12, the energy of the pulsed laser light fluctuates. For example, 1
± 15% when the oscillation cycle fluctuates at 3 Hz, 3 Hz
± 7% for 20Hz oscillation, ± 3% for 20Hz oscillation, 100%
In the case of oscillation at Hz, the irradiation energy per unit area fluctuates, such as ± 2%. Therefore, it is preferable that the YAG pulse laser oscillator 10 be continuously oscillated.
This is the reason for using the damper 25.

As described above, the ceramic plate 11
By irradiating a pulsed laser beam having an arbitrary shape such as a rectangular shape smaller than the size in an arbitrary irradiation pattern, a sufficient distortion can be given without generating a crack. Since a single irradiation area is effective for cracking, it is preferable that the single irradiation area be as small as possible.

FIG. 3 shows that the mask 14 irradiates the entire surface of the ceramic plate 11 with a pulsed laser beam shaped into a pulsed laser beam having a linear cross-sectional area sufficiently smaller than the area of the ceramic plate 11. The pattern of the case is shown. The galvano scanner 13 can irradiate the entire surface of the ceramic plate 11 by oscillating and irradiating the ceramic plate 11 with pulsed laser light having a linear cross-sectional area in the order indicated by the arrow in FIG. . In this case, the galvanometer scanner 13 does not need to be a two-axis type, and may have a function of scanning in one axis direction by one galvanometer mirror.

When the laser beam is shaped into a pulsed laser beam having a linear cross-sectional area, a mask having a simple laser beam passage hole has a length size larger than the cross-sectional area of the incident pulsed laser beam. It cannot be shaped into a linear cross section. In this case, by using a well-known optical means, for example, a cylindrical lens as a mask means, it is possible to shape the pulsed laser light having a certain cross-sectional area into a linear cross-sectional area having a longer length size. it can. In addition, giving distortion means not only processing the ceramic plate to be convex or concave, but also processing the ceramic plate to correct the deformation of the convex or concave generated in the manufacturing process. Also means. The laser oscillator is not limited to the YAG pulse laser oscillator, and another laser oscillator such as a YLF pulse laser oscillator can be used.

[0030]

As described above, according to the present invention, a ceramic plate is irradiated with a pulsed laser beam having a smaller cross-sectional area than its size a plurality of times so as to cover the entire irradiation region. By doing so, even in the case of a ceramic plate having a defective portion inside, a sufficient distortion can be given without generating cracks. Therefore, according to the present invention, it is possible to provide a method and an apparatus for processing a ceramic material having a high yield.

[Brief description of the drawings]

FIG. 1 is a view showing a configuration of a processing apparatus for a ceramic material according to the present invention.

FIG. 2 is a diagram showing an example of an irradiation pattern of a pulsed laser beam applied to a ceramic plate according to the present invention.

FIG. 3 is a diagram showing another example of an irradiation pattern of a pulsed laser beam applied to a ceramic plate according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 YAG pulse laser oscillator 11 ceramic plate 12 stage 13 galvano scanner 14 mask 15, 16 imaging lens 17 collimation lens 18 uniform optical system 21 to 24, 26 reflection mirror 25 damper 27 observation optical system 28 energy monitor

Claims (8)

[Claims] 1. A processing method for irradiating a ceramic plate with pulsed laser light from a laser oscillator to apply distortion to the ceramic plate, wherein the pulsed laser light having a smaller cross-sectional area than the area of the ceramic plate is applied to the ceramic plate. A ceramic material processing method using a laser, wherein the ceramic plate is prevented from cracking by irradiating the ceramic plate a plurality of times so as to cover the entire irradiation area of the ceramic material. 2. The method for processing a ceramic material according to claim 1, wherein the pulsed laser beam has a square or linear cross section. 3. The method for processing a ceramic material according to claim 2, wherein the pulsed laser light having a rectangular or linear cross section is swung by a galvano scanner to cover the entire irradiation area of the ceramic plate. A method for processing a ceramic material by using a laser, wherein irradiation is performed a plurality of times. 4. The method for processing a ceramic material according to claim 3, wherein a mask means for defining a cross-sectional shape of the pulsed laser light is disposed between the laser oscillator and the galvano scanner. A method of processing a ceramic material by using a laser. 5. A pulsed laser oscillator, mask means for defining a cross-sectional shape of the pulsed laser light emitted from the pulsed laser oscillator, and pulsating the pulsed laser light passing through the mask means. A galvano scanner, and an imaging lens for imaging the pulsed laser light oscillated by the galvano scanner on a ceramic plate mounted on a stage, wherein the mask means includes the pulsed laser. It is for making the cross-sectional area of the light a smaller cross-sectional area than the area of the ceramic plate, and the galvano scanner emits the pulsed laser light having the smaller cross-sectional area over the entire irradiation area of the ceramic plate. And a laser processing apparatus for processing a ceramic material by laser. 6. The apparatus according to claim 5, wherein a collimation lens is disposed between the galvano scanner and the imaging lens. 7. The ceramic material processing apparatus according to claim 5, wherein an energy intensity in a cross-sectional area of the pulsed laser light from the laser oscillator is made uniform between the laser oscillator and the mask means. For processing a ceramic material by means of a laser, wherein a uniform optical system is arranged for the purpose. 8. The apparatus for processing a ceramic material according to claim 5, wherein the stage is movable in an X-axis direction and a Y-axis direction, and a plurality of the ceramic plates are mounted on the stage. An apparatus for processing a ceramic material using a laser.