KR101774290B1 - Method and apparatus of processing brittle material with laser pin beam and optical system for the same - Google Patents

Abstract

The present invention relates to an apparatus for processing brittle materials by using laser pin beams. According to the present invention, the laser processing apparatus includes: a first optical system converting an ultra-short pulse laser beam transmitted from a laser generation unit while having Gaussian energy distribution to a Bessel beam distributing energy on multiple concentric circles around an optical shaft and the optical shaft with reference to a cross-section perpendicular to the progressing direction of the ultra-short pulse laser beam; a second optical system concentrating the Bessel beam or beams scattered from the Bessel beam to generate a pin beam concentrating energy on spots on the optical shaft with reference to the cross-section perpendicular to the progressing direction; and a third optical system concentrating the pin beam or beams scattered from the pin beam onto the inside of the brittle material. The present invention enables ultra-high concentration of the ultra-short pulse laser beam around the optical shaft to generate the pin beam with little variation in the beam diameter in the beam progressing direction and process the brittle material with the laser pin beam to cut a mirror surface without any melting, breaking, or cracking.

Description

TECHNICAL FIELD The present invention relates to a brittle material processing method and apparatus using a laser pin beam and an optical system for the same.

More particularly, the present invention relates to a method and apparatus for processing a brittle material using a laser, and more particularly, to a method and apparatus for processing a brittle material using a laser, in which a pulsed laser having a pulse width of a picosecond to a femtosecond pulse is converted into a pin beam focused at an ultra- To a method and apparatus for processing a brittle material.

A laser processing apparatus is a device for cutting a material or forming a hole by focusing a continuous wave or a pulsed wave laser through an optical system. Recently, a pulsed laser is used which can cause filamentation in the field of processing transparent materials such as glass.

Filamentation phenomenon is a phenomenon in which a self-focusing (self-focusing) and defocusing are consecutively generated due to Kerr effect when an ultra-short pulse laser beam having a pulse width of picosecond to femtosecond is irradiated to a transparent material such as glass, This means that the plasma spots continuously occur in the transparent material over the irradiation length of several to several tens of Rayleigh lengths along the irradiation direction of the beam.

When a plasma spot is generated in the transparent material, the refractive index of the plasma spot is increased. If the plasma spot is over the damage threshold, the portion is permanently modified and cracks and / or cavities are generated. .

On the other hand, if a brittle material such as glass has cracks on the cut surface or is not smooth, cracks propagate from the cut surface even after a slight impact, resulting in product failure. For this reason, in the field of displays using thin glass substrates of several to several hundreds of micrometers, there is a very strict requirement for the roughness of the cut surfaces.

Conventionally, in order to meet such a demand, a subsequent process of mechanically polishing or chemically etching the cut surface after processing has been carried out. However, in recent years, studies have been actively made to improve the roughness by controlling the energy distribution and beam shape of the laser beam have.

For example, Patent Document 1 and Patent Document 2 have been proposed in order to solve problems in processing a brittle material by using a laser beam having a Gaussian energy distribution (hereinafter referred to as a "Gaussian beam").

In general, as the Gaussian beam advances, the energy density and the peak power are greatly reduced as the beam is diffused. Therefore, it is known that a high-power laser light source should be used for material processing and the cut surface is very rough because the energy distribution inside the material is uneven.

In order to solve this problem, Patent Documents 1 and 2 convert a Gaussian beam into a bessel beam having a plurality of ring-shaped energy distributions on the basis of a cross section orthogonal to the traveling direction, without using the Gaussian beam intact And introduces the technology of processing the brittle material by using it.

Hereinafter, a laser processing technique using a vessel beam will be described with reference to FIG. 1 (a) shows the optical system configuration, and (b) and (c) in FIG. 1 show the cross-sectional shape and the energy density distribution of the laser beam at various positions of the optical system.

1, the microwave Gaussian beam 1 transmitted from a laser light source (not shown in the drawing) passes through an axicon lens 10 and is converted into a vessel beam. The Beessel beam has the largest energy density on the optical axis and a large number of concentric energy density distributions around the optical axis.

This vessel beam is defocused by passing through the depth of focus of the axicon lens 10, so that after proceeding a certain distance from the depth of focus, there is no energy distribution in the vicinity of the optical axis and the ring beam is converted into a ring- .

The ring beam formed by defocusing the Beessel beam travels in a direction substantially parallel to the optical axis by a collimator lens 20 and is incident on the focusing lens 30. The focusing lens 30 focuses the incident ring beam And converts the beam to a beam beam.

The beam diameter of the vessel lens formed by the focusing lens 30 is much higher than that of the vessel lens formed by the axicon lens 10 because the diameter of the beam is very small. In addition, since the vessel beam includes a plurality of focal points along the traveling direction in the depth of focus, an energy-concentrated region of approximately rhombic shape appears as shown in FIG. Hereinafter, the focus depth section and the energy concentrated area formed around the focus depth section are referred to as a focus beam 1a for convenience.

Patent Literatures 1 and 2 relate to a technique of processing a material using such a focal beam 1a. In Patent Document 1, as shown in Fig. 2, a focal beam 1a is formed inside a brittle material 50 And Patent Document 2 relates to a technique of forming the focus beam 1a on the outside of the brittle material 50 and processing it as shown in Fig.

However, since the focal beam 1a has a shape close to the rhombus, the width is not constant along the traveling direction, and there is considerable residual energy around the optical axis because of Bezer beam. Therefore, when the focus beam 1a is positioned inside the material as in Patent Document 1, there is a limit in realizing the energy distribution of a certain diameter along the thickness direction of the material.

On the other hand, in Patent Document 2, since the focus beam 1a is located outside the material, the influence due to the residual energy can be reduced. Also, although the focus beam 1a is incident on the material in a slightly defocused state, since it is incident on the material in a state in which energy is concentrated at the end of the focus beam 1a, the focus beam 1a is relatively constant The energy distribution of the diameter can be realized.

For this reason, it is known that when cut by the method according to Patent Document 2, a cut surface that is much smoother than that of Patent Document 1 can be obtained.

However, in the processing techniques of Patent Documents 1 and 2, a material is processed by using a femtosecond beam of focus beam 1a. Since residual energy is widely present around the focus beam 1a, the thickness direction of the material It is difficult to realize a constant diameter energy distribution. As a result, there is a certain limit in improving the roughness of the cut surface, and there is a limit to increase energy efficiency.

In addition, since the focusing lens 30 focuses the ring beam having a relatively large diameter to form the focus beam 1a of the vessel beam shape, there is a limitation in reducing the diameter of the focus beam 1a, .

Further, there is a problem that when the material is separated after the cutting process due to the melting or cracking of the cutting surface, damage occurs or the material is not easily separated.

Further, in the conventional processing technique, it is difficult to cut the plywood having two or more substrates stacked one by one when cutting the plywood. Therefore, there is a limit to increase the productivity of the plywood because cutting the plywood in order of cutting, flipping, and other cutting in order.

In recent years, not only the substrate thickness has become thinner but also the technical requirements for the roughness of the cut surface have become more strict due to the appearance of the curved surface display. Therefore, there is a need to develop a new machining technology capable of cutting the mirror surface .

Korean Patent Publication No. 10-2016-0010397 (2016.01.27) Korean Patent Publication No. 10-2016-0010041 (2016.01.27)

SUMMARY OF THE INVENTION The present invention has been made to solve such conventional problems, and it is an object of the present invention to enable mirror surface cutting without any melting, cracking or cracking when a brittle material is processed by a laser.

It is also an object of the present invention to provide a laser processing technique capable of processing a material with a much smaller line width than conventional ones and improving energy efficiency.

It is also an object of the present invention to provide a laser processing technique capable of mirror-cutting a plurality of plywoods with the same quality even when two or more plywoods are cut.

It is also an object of the present invention to provide a laser processing technique that can more easily separate a material after a cutting process.

In order to achieve the above object, one aspect of the present invention is to provide a microwave pulse laser beam transmitted from a laser generation unit, the beam having an energy distribution on an optical axis and a plurality of concentric circles around the optical axis, Into a first optical system; A second optical system for focusing a beam dispersed from the vessel beam or the vessel beam and generating a pin beam having a spot-like energy concentrated on an optical axis on the basis of a cross section orthogonal to the traveling direction; And a third optical system for focusing the dispersed beam from the pin beam or the pin beam into the brittle material.

In the optical system for a laser according to an aspect of the present invention, the distance d between the end of the depth of focus of the first optical system and the incident surface of the second optical system may be 0 to 0.1 mm.

Further, in the optical system for a laser according to an aspect of the present invention, the first optical system includes an axicon lens, and the second optical system includes a collimator lens or an aspheric lens .

According to another aspect of the present invention, there is provided a laser processing apparatus comprising: a first optical system for converting an ultra-violet pulsed laser beam transmitted from a laser generation unit into a ring beam having a ring-shaped energy distribution about an optical axis with respect to a cross- A second optical system for converging the ring beam and generating a pin beam having energy concentrated in a spot shape on an optical axis based on a cross section orthogonal to the progress direction; And a third optical system for focusing the dispersed beam from the pin beam or the pin beam into the brittle material.

In the optical system for laser according to another aspect of the present invention, the incident surface of the second optical system may be located inside the depth of focus of the first optical system.

In addition, in the optical system for laser according to another aspect of the present invention, the first optical system may include a vortex lens, and the second optical system may include a collimator lens or an aspheric lens. have.

In the optical system for a laser according to one or more aspects of the present invention, the third optical system has a depth of focus of 0.1 to 3 占 퐉, a numerical aperture (NA value) of 0.1 to 1.0, a transmittance of 50% to 99% , And the magnification may be from 20 to 100.

According to still another aspect of the present invention, there is provided a method of modulating a microwave pulsed laser beam, comprising: converting a microwave pulsed laser beam transmitted from a laser generating unit into a Beesel beam having an energy distribution on an optical axis and a plurality of concentric circles around an optical axis, Focusing a dispersed beam from the vessel beam or the vessel beam to generate a pin beam focused on an optical axis in a spot shape on the basis of a cross section orthogonal to the traveling direction; And focusing the dispersed beam from the pin beam or the pin beam into the brittle material.

According to still another aspect of the present invention, there is provided a method of driving a microwave pulse laser, comprising the steps of: converting an ultra-short pulse laser beam transmitted from a laser generation unit into a ring beam having a ring-shaped energy distribution about an optical axis with respect to a cross- Focusing the ring beam to generate a pin beam having energy concentrated in a spot shape on an optical axis with respect to a cross section orthogonal to the traveling direction; And focusing the dispersed beam from the pin beam or the pin beam into the brittle material.

The brittle material processing method according to the present invention is characterized in that the brittle material processing method comprises applying a force to the brittle material away from the cut surface on both sides away from the cut surface or applying a force pressing the outgoing surface from both sides away from the cut surface of the brittle material, And applying a pressing force to the cut surface to separate the cut surface.

According to the present invention, a microwave pulse laser beam is focused at a very high density in the vicinity of an optical axis to form a pin beam having a very small variation in beam diameter along the advancing direction of the beam, A mirror surface cutting without melting, cracking or cracking can be realized.

Further, according to the present invention, since the cut surface cut by the pin beam is very clean, the cut material can be easily separated, and damage such as cracks can be prevented in the separation process. In addition, since the diameter of the pin beam formed inside the brittle material is very small, the machining accuracy can be greatly improved.

Also, since the laser pin beam according to the present invention has a very high energy density at the optical axis compared to the vessel beam or the Gaussian beam, it can use a relatively low-power laser light source, thereby improving energy efficiency and productivity.

In addition, according to the present invention, a pin beam having a length similar to or longer than the thickness of a brittle material can be formed. Therefore, the entirety of the material can be cut without adjusting the focus of the focusing lens, The above plywood can be cut at the same quality with the same quality.

1 is a block diagram of a conventional laser machining apparatus
2 is a view showing a state in which a focus beam in the form of a vessel beam is formed in a transparent material and processed
3 is a view showing a state in which a focus beam in the form of a vessel beam is formed on a transparent material and processed
4 is a diagram showing the configuration of a laser machining apparatus according to the first embodiment of the present invention
5 is a view showing the position of the second optical system
FIG. 6 is a view for comparing the focus beam shapes of a Gaussian beam, a vessel beam, and a pin beam;
7 is a view showing a state in which the interval between the second optical system and the third optical system is adjusted;
8 is a view showing a state in which the interval between the first optical system and the second optical system is adjusted;
9 is a flowchart of a brittle material processing method according to the first embodiment of the present invention
10 is a cross-sectional view
11 is a view showing a separation method after cutting;
12 is a configuration diagram of a laser machining apparatus according to a second embodiment of the present invention

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

It is to be noted that the term " including any element " in this specification means that the element may include other elements instead of excluding other elements, unless specifically stated otherwise. Also, the singular presentation may include plural meanings unless the context clearly dictates otherwise. It should be understood that the drawings are not intended to limit the scope of the present invention in any way.

First Embodiment

4 is a schematic diagram of a laser processing apparatus for brittle material processing according to the first embodiment of the present invention. FIG. 4A shows the optical system configuration, and FIGS. 4B and 4C show the cross-sectional shape and the energy density distribution of the laser beam at various positions of the optical system, respectively.

The laser processing apparatus according to the first embodiment of the present invention includes a laser generating unit (not shown in the figure), a first optical system 110, a second optical system 120, and a third optical system 130. Although not shown in the drawing, a transmission optical system including an optional combination of a mirror, a diaphragm, and a splitter may be disposed between the laser generating unit and the first optical system 110.

The laser generating unit generates a microwave pulse laser beam. For example, a microwave pulse laser beam having a pulse width of femtosecond (FS) to picosecond (PS), and the laser wavelength region may be, for example, 515 nm to 1550 nm. However, the pulse width and the wavelength band are not limited thereto.

On the other hand, the laser generator preferably outputs a single mode pulse laser instead of a burst mode. Pulse lasers in burst mode have a lower peak output than single mode, which limits the energy density of the pin beam. However, the present invention is not limited to this, and a burst mode laser may be used depending on the laser output or processing conditions.

The first optical system 110 converts the Gaussian beam propagated from the laser generating unit into a vessel beam, and may include, for example, an axicon lens or an axicon lens.

As shown in the drawing, the Beessel beam generated by the first optical system 110 has the largest energy density in the optical axis and a large number of concentric energy density distributions around the optical axis.

The second optical system 120 focuses the laser beam transmitted from the first optical system 110 to form a pin beam. For example, a collimator lens or an aspheric lens, Or may include a collimator lens or an aspherical lens.

It is preferable that the second optical system 120 is installed at a position very close to the focal point of the first optical system 110. Thus, energy concentrated in the vessel beam generated by the first optical system 110 is not scattered but focused in the vicinity of the focus of the second optical system 120, so that an ultra-high-density pin beam can be formed.

The focal point of the second optical system 120 is preferably located between the second optical system 120 and the third optical system 130. Although the drawing shows that the focus of the second optical system 120 is located between the second optical system 120 and the third optical system 130, the present invention is not limited thereto. For example, the incident surface of the third optical system 130 may be positioned near the focal point of the second optical system 120.

As shown in the figure, the energy density distribution of the pin beam formed at the focus of the second optical system 120 is such that most energy is concentrated on the optical axis and negligible extra energy exists around the optical axis . Therefore, energy is concentrated in the center as a whole and has an energy density distribution similar to a fin.

In another aspect, the pin beam formed at the focal point of the second optical system 120 has a spot shape with respect to a cross section orthogonal to the traveling direction.

The pin beam formed by the second optical system 120 may slightly diffract from the focal point of the second optical system 120 and may be deformed into a shape similar to the Beessel beam and incident on the third optical system 130.

5 illustrates the position of the second optical system 120 with respect to the first optical system 110. When the incident surface of the second optical system 120 is shifted from the end of the depth of focus Z of the first optical system 110 (D).

The distance d can be appropriately selected depending on the optical characteristics of the first optical system 110 and the second optical system 120, the diameter of the laser beam incident on the first optical system 110, and the like.

According to the experiment, when the distance d is 0 to 0.1 mm, the energy density near the optical axis of the pin beam formed at the focal point of the second optical system 120 is the highest.

Since the energy of the vessel beam tends to be strongly concentrated at the end of the focus depth z, it is possible to maximize the energy density of the pin beam when the second optical system 120 focuses the vessel beam before it is dispersed and converted into a ring beam It is because.

However, depending on the laser output characteristic or the specification of the brittle material, the incident surface of the second optical system 120 may be set such that the incident surface of the second optical system 120 is slightly ahead of the end of the depth of focus Z of the first optical system 110 , Or may be spaced by 0.1 mm or more from the end of the depth of focus Z. [

The third optical system 130 is a kind of focusing lens, and functions to focus the pin beam formed by the second optical system 120 to a specific position inside the brittle material. That is, the focus of the third optical system 130 is located inside the transparent brittle material to be processed.

As described above, the pin beam formed by the second optical system 120 may be deformed in a similar manner to the vessel beam in the course of the process, and may be incident on the third optical system 130. However, since the Bezel beam incident on the third optical system 130 is much smaller in diameter than the Bezel beam formed by the first optical system 110, if the beam is focused again through the third optical system 130, a very dense pin A beam can be formed.

According to the experiment, it is preferable that the depth of focus of the third optical system 130 is 0.1 to 3 탆. Further, the numerical aperture (NA) of the third optical system 130 is between 0.1 and 1.0, and preferably between 0.5 and 0.99. The transmittance of the third optical system 130 is preferably in the range of 50% to 99% or less. Also, the magnification of the third optical system 130 is preferably selected from a magnification of from 20 to 100. [

6, which shows the focal position of the Gaussian beam, most of the energy is concentrated at the center of the material (Fig. 6 (a)), and the vessel beam is roughly diamond-shaped, but like the Gaussian beam, (Fig. 6 (b)). On the other hand, in the laser pin beam according to the present invention, energy is distributed with a very constant width along the thickness direction of the work, as shown in Fig. 6 (c).

Also, it is known that when the focus is formed in the material by a Gaussian beam, the diameter of the focus beam is about 20 to 35 mu m, and when the focus is formed by the vessel beam, the diameter of the focus beam is about 10 to 15 mu m have.

On the other hand, according to the embodiment of the present invention, since the focal beam of the generated laser pin beam has a diameter of about 0.5 to 1.8 탆, the material can be precisely processed with a line width much smaller than that of a Gaussian beam or a vessel beam. In addition, since the laser beam has a much more uniform energy distribution in the thickness direction of the material, it is possible to uniformly cut the laser beam from the incident surface to the emission surface and to minimize the melting and cracking due to energy unbalance, It is possible.

More specifically, the picosecond to femtosecond lasers have very short pulse widths and high peak energies, resulting in high-density energy superimposition in a very small area.

Particularly, since the laser beam beam according to the embodiment of the present invention has high density energy instantaneously concentrated in a very narrow region compared with the vessel beam or the Gaussian beam, the pulse energy is transferred to the brittle material while overlapping each other, do.

In addition, the microwave pulses incident into the brittle material generate heat and disappear for a very short period of time, minimizing the re-fusion of the material and the thermal deformation of other parts, thereby achieving a very smooth cut surface.

In addition, the high-density pulse energy of the laser pin beam is strongly concentrated in a very small area and has a strong straightness. As a result, a pin-shaped energy focused area (focus beam) is formed along the traveling direction inside the brittle material.

That is, although the depth of focus of the third optical system 130 is only about 0.1 to 3 탆, heat accumulation and laser plasma interaction due to the pulse energy superimposition described above are generated inside the brittle material A very long and constant diameter focal beam is formed as it occurs in a complex manner.

For example, if the focus of the laser pin beam is formed in the middle of the glass having a thickness of 500 탆, the focus beam is formed to have a length of about 200 탆, and a very clean cut surface can be obtained by such a long and uniformly formed focus beam.

In particular, the energy which is superimposed strongly on the focus beam is transmitted to the incident surface and the exit surface along the path of the laser pin beam, so that the mirror surface is cut in the front and rear of the focus beam. Do.

According to the experiment, when the laser processing apparatus according to the embodiment of the present invention is used to cut a 300 μm glass with a laser having a pulse width of 10 to 15 picoseconds and a pulse energy of 200 μJ, mirror-surface cutting is possible, It was shown that 300 ~ 500μm glass can be mirror-cut using laser. Therefore, it can be seen that the thicker the glass, the shorter the pulse width and the larger the energy of the expansion is, the mirror-surface can be cut.

Since the energy distribution along the thickness direction of the material of the laser pin beam according to the embodiment of the present invention is very uniform, the plywood can be simultaneously mirror-cut at one time without flipping even when cutting the plywood rather than the single plywood.

According to the experiment, two glass substrates each having a thickness of about 0.005 mm to 1.0 mm were attached with an air gap of 0.005 mm to 0.1 mm interposed therebetween. As a result, the two glass substrates had almost the same quality It was confirmed that the mirror surface was cut.

In addition, when a material is processed using a vessel beam, a laser output of about 12 to 20 W is required. However, according to the present invention, it is possible to process only a laser output of about 1 to 5 W due to a high energy density of a pin beam. Therefore, according to the present invention, there is an advantage that the energy efficiency can be greatly improved as compared with the prior art, and the process cost can be greatly reduced.

As described above, according to the embodiment of the present invention, the machining quality and productivity of the brittle material can be greatly improved as compared with the conventional method using the laser ablation using the Gaussian beam or the vessel beam.

The laser processing apparatus according to the first embodiment of the present invention may adjust the width and length of the pin beam incident on the brittle material. More specifically, the beam width of the Gaussian beam incident on the first optical system 110 may be adjusted, the distance between the first optical system 110 and the second optical system 120 may be adjusted, or the distance between the second optical system 120 and the third optical system 120 may be adjusted. The width and length of the laser pin beam can be adjusted by adjusting the interval of the optical system 130.

7, the first station 210 supporting the first optical system 110 and the second optical system 120 is moved along the optical axis direction while the second optical system 120 and the third optical system 120 are moved, The width of the beam incident on the third optical system 130 is changed by varying the distance of the pin 130, so that the length or width of the pin beam incident on the material can be controlled.

8, the second station 220 supporting the second optical system 120 and the third optical system 130 is moved along the optical axis direction while the first optical system 110 and the second optical system 130 are moved, The width of the beam incident on the second optical system 120 is changed by varying the distance of the first optical system 120, so that the length or width of the pin beam incident on the material can be controlled.

As another example, it is possible to control the beam width of the laser beam incident on the first optical system 110 and adjust the distance between the lenses 110, 120, and 130 using the first station 210 and / or the second station 220, While adjusting the length or width of the pin beam incident on the material.

Although not shown in the figure, the first station 210 may include a support structure such as a case or a support rod for fixing the first optical system 110 and the second optical system 120 by a predetermined distance. And may include driving means such as a conveying rail and a motor for moving the first station 210.

Similarly, the second station 210 may include a supporting structure for fixing the second optical system 120 and the third optical system 130 by a predetermined distance, and may include driving means such as a conveying rail, a motor, and the like.

Hereinafter, a brittle material processing method according to the present invention will be described with reference to the flowchart of FIG.

First, the microwave laser beam generated by the laser generation unit is incident on the first optical system 110 through a transmission optical system in the form of a Gaussian beam having a Gaussian energy distribution. (S10)

The first optical system 110 diffracts the incident laser beam and converts the laser beam into a vessel beam having a plurality of concentric energy distributions with respect to a cross section orthogonal to the traveling direction.

The Beessel beam is focused on the focal point of the second optical system 120 through the second optical system 120 provided close to the end of the focal depth of the first optical system 110 and converted into a pin beam having a high density of energy on the optical axis. (S30)

The pin beam generated by the second optical system 120 is focused again by the third optical system 130 into the pinned beam inside the brittle material, and the brittle material is processed along the incident direction of the pin beam. (S40, S50)

10 is a photograph (a, b) showing the result of the glass processing according to the prior art and a photograph (c, d) showing the result of the glass processing according to the embodiment of the present invention.

10 (a) shows a case where a glass is cut using the Gaussian beam filaments, and the roughness of the cut surface is not smooth to about 0.4 탆 to 0.5 탆, and fine cracks exist.

10 (b) shows a case where glass is cut by using a vessel beam. Although the cut surface is smooth as compared with Fig. 10 (a), it is not smooth enough to be 0.2 micrometers to 0.3 micrometers. In addition, cracking occurs during the separation process because the vessel is cut relatively smoothly in the concentrated region of the energy of the beam and the surrounding region is not cut properly.

On the other hand, according to the embodiment of the present invention, when the glass is cut by using the laser pin beam, the roughness of the cut surface can be lowered to 0.01 탆 or less and down to a maximum of 0.001 탆. Therefore, according to the present invention, as shown in Fig. 10 (c), it is possible to obtain a smoother cut surface as compared with the above (a) and (b), as well as a mirror-surface cut without cracks at all.

10 (d), even when the plywood having an air gap in the middle is cut, it can be seen that the two plywood are cut smoothly with almost the same quality.

On the other hand, although the cutting method using the laser pin beam is the method of cutting energy by transmitting the energy most efficiently to the brittle material, the refraction and diffuse reflection of the beam inside the material and the extra energy of the edge of the pin beam it is impossible to distribute the energy perfectly uniformly throughout the section because it has a greater impact on the bottom surface than on the surface.

For this reason, even if a brittle material is mirror-finished using a laser pin beam, it is necessary to consider the directionality when separating the brittle material.

For example, assuming that mirror-surface cutting is performed using the laser pin beam as shown in FIG. 11 (a), if force is applied in a direction perpendicular to the cutting surface, that is, in a direction away from the cutting surface as shown in FIG. 11 And the cut surface can be made smooth.

Further, as shown in Fig. 11 (c), a downward pressing force is applied to the upper surface (incident surface) of the brittle material in the vicinity of the cut surface, and at the same time, When you apply the force to lift, it is easily separated and the cut surface becomes smooth.

On the other hand, as shown in Fig. 11 (d), a force for lifting upward the lower surface (emergent surface) of the brittle material is applied in the vicinity of the cut surface and at the same time, If the downward pressing force is applied, not only can not easily be separated, but the cut surface is not smooth even if it is separated.

In other words, when the brittle material having been subjected to the cutting process is separated, the lower end (the exit surface end) of the two side cut surfaces comes into contact with each other or the force is applied in a direction that does not interfere with each other to separate the desired unit from the scrap more easily .

Second Embodiment

12 (a) and 12 (b) show the optical system configuration, and FIGS. 12 (b) and 12 (c) Sectional shape and energy density distribution of the laser beam at various positions of the laser beam.

As shown in the drawings, the laser processing apparatus according to the second embodiment of the present invention includes a first optical system 110a, a second optical system 120, and a third optical system 130. [ Although not shown in the drawings, the laser generating unit may include a transmitting optical system including an optional combination of a mirror, a diaphragm, and a splitter between the laser generating unit and the first optical system 110, as in the first embodiment .

In the first embodiment of the present invention, the first optical system 110 converts the Gaussian beam transmitted from the laser generator into a vessel beam, but in the second embodiment of the present invention, the first optical system 110a converts the Gaussian beam into a ring beam And is incident on the second optical system 120, which is different from the first embodiment.

The first optical system 110a may be, for example, a vortex lens or a vortex lens, and the vortex lens changes the path of the incident Gaussian beam so as to proceed while rotating helically about the optical axis. Therefore, the laser beam passing through the vortex lens has a helical energy distribution with respect to the cross section orthogonal to the traveling direction.

However, in the focus of a Vortex lens, the energy density distribution is converted from a helical shape to a ring shape, so that there is no energy distribution in the vicinity of the optical axis, and a ring beam is formed in which energy is concentrated only in the periphery.

In the first embodiment, it is preferable that the vessel beam formed by the first optical system 110 is converged to the second optical system 120 to form a fin beam before being dispersed into the ring beam. However, Since the ring beam is large in diameter, the energy density can be lowered by converting into a pin beam.

However, since the ring beam formed at the focal point of the vortex lens has a very small diameter as well as a very high energy density as compared with the ring beam formed by dispersing the vessel beam in the first embodiment, To the pin beam of FIG.

The second optical system 120 functions to focus the ring beam formed at the focal point of the first optical system 110a and form a pin beam. The second optical system 120 may be a collimator lens, an aspheric lens, a collimator lens, Lens.

It is preferable that the incident surface of the second optical system 120 is located within the depth of focus of the first optical system 110a so that before the energy of the ring beam formed at the focus of the first optical system 110a is dispersed, 120 to a pin beam.

It is preferable that the focal point of the second optical system 120 be positioned between the second optical system 120 and the third optical system 130 as in the first embodiment.

When the ring beam generated by the first optical system 110 is converged on the focal point of the second optical system 120, a spot-shaped high density region in which most of the energy is concentrated near the optical axis when viewed from the cross- And converted into a pin beam.

The third optical system 130 is a focusing lens, and focuses the pin beam formed by the second optical system 120 into the inside of the brittle material. The depth of focus, numerical aperture, transmissivity, and the like of the third optical system 130 are as described in the first embodiment.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It is to be understood that the invention is not limited to the disclosed embodiments.

50: brittle material 110: first optical system,
120: second optical system 130: third optical system,
210: first station 220: second station.

Claims (12)

A first optical system for converting a microwave pulse laser beam having a Gaussian energy distribution transmitted from a laser generating unit into a Beessel beam having an energy distribution on an optical axis and a plurality of concentric circles around the optical axis on the basis of a cross section orthogonal to the traveling direction;
A second optical system for focusing a beam dispersed from the vessel beam or the vessel beam and generating a pin beam having a spot-like energy concentrated on an optical axis on the basis of a cross section orthogonal to the traveling direction;
And a third optical system for focusing the dispersed beam from the pin beam or the pin beam into the brittle material
An optical system for laser for brittle material processing The method according to claim 1,
Wherein a distance d between an end of the depth of focus of the first optical system and an incident surface of the second optical system is 0 to 0.1 mm. 3. The method according to claim 1 or 2,
Wherein the first optical system includes an axicon lens and the second optical system includes a collimator lens or an aspheric lens. A first optical system for converting a microwave pulse laser beam having a Gaussian energy distribution transmitted from a laser generator into a ring beam having a ring-shaped energy distribution about an optical axis with respect to a cross section orthogonal to a traveling direction;
A second optical system for converging the ring beam and generating a pin beam having energy concentrated in a spot shape on an optical axis based on a cross section orthogonal to the progress direction;
And a third optical system for focusing the dispersed beam from the pin beam or the pin beam into the brittle material
And an optical system for laser processing for processing a brittle material. 5. The method of claim 4,
And the incident surface of the second optical system is located inside the focal depth of the first optical system. The method according to claim 4 or 5,
Characterized in that the first optical system comprises a vortex lens and the second optical system comprises a collimator lens or an aspheric lens. The method according to claim 1 or 4,
Wherein the third optical system has a focal depth of 0.1 to 3 占 퐉, a numerical aperture (NA value) of 0.1 to 1.0, a transmittance of 50% to 99%, and a magnification of 20 to 100 Optical system for laser A laser generator for generating a microwave pulse laser beam;
A first optical system for converting an ultra-short pulse laser beam having a Gaussian energy distribution transmitted from the laser generator into a Bezel beam having an optical axis and a plurality of concentric circles around the optical axis on the basis of a cross section orthogonal to the progress direction;
A second optical system for focusing a beam dispersed from the vessel beam or the vessel beam and generating a pin beam having a spot-like energy concentrated on an optical axis on the basis of a cross section orthogonal to the traveling direction;
And a third optical system for focusing the dispersed beam from the pin beam or the pin beam into the brittle material
A laser processing apparatus for processing a brittle material A laser generator for generating a microwave pulse laser beam;
A first optical system for converting a microwave pulse laser beam having a Gaussian energy distribution transmitted from the laser generator into a ring beam having a ring-shaped energy distribution around an optical axis with respect to a cross section orthogonal to the traveling direction;
A second optical system for converging the ring beam and generating a pin beam having energy concentrated in a spot shape on an optical axis based on a cross section orthogonal to the progress direction;
And a third optical system for focusing the dispersed beam from the pin beam or the pin beam into the brittle material
And a laser processing device for processing a brittle material. Converting a microwave pulse laser beam having a Gaussian energy distribution transmitted from a laser generating part into a Bezel beam having an optical axis and a plurality of concentric circles around the optical axis on the basis of a cross section orthogonal to the traveling direction;
Focusing a dispersed beam from the vessel beam or the vessel beam to generate a pin beam focused on an optical axis in a spot shape on the basis of a cross section orthogonal to the traveling direction;
Focusing the dispersed beam from the pin beam or the pin beam into the brittle material
A brittle material processing method using laser comprising Converting a microwave pulse laser beam having a Gaussian energy distribution transmitted from a laser generating unit into a ring beam having a ring-shaped energy distribution around an optical axis with respect to a cross section orthogonal to the traveling direction;
Focusing the ring beam to generate a pin beam having energy concentrated in a spot shape on an optical axis with respect to a cross section orthogonal to the traveling direction;
Focusing the dispersed beam from the pin beam or the pin beam into the brittle material
A brittle material processing method using laser comprising The method according to claim 10 or 11,
Applying a force away from the cut surface at both sides away from the cut surface of the brittle material or applying a force pressing both sides of the brittle material at both sides away from the cut surface and applying a force pressing the incident surface near the cut surface to separate the cut surface Further comprising the steps of: (a)

Images