TWI579089B - Laser processing device for glass substrates - Google Patents

Description

Laser processing device for glass substrate

The present invention relates to a laser processing apparatus for cutting a glass substrate of a surface-strengthened glass substrate, and more particularly to a laser processing apparatus suitable for a glass substrate for forming an annular processing mark on a glass substrate.

When a liquid crystal display panel is manufactured, exposure and development are repeated on the glass substrate to form a pattern composed of a predetermined pixel and a circuit. At this time, a pattern of a plurality of panels is simultaneously formed on one glass substrate, and then the glass substrate is divided to manufacture each panel. Conventionally, the division of the glass substrate is performed by a mechanical cutting process in which a predetermined line is cut by a rotary blade line (Patent Document 1).

However, in this mechanical cutting process, it is necessary to move the dicing blade along the line to cut at a low speed, and the processing time per one glass substrate is long, so that there is a problem that manufacturing efficiency is inferior. In addition, there is a problem in that the glass substrate is easily broken during the cutting step, and the yield is low, and chips are generated when cutting by the rotary blade. In particular, when the surface is tempered glass, the above problems are more remarkable.

Therefore, we have proposed a technique for forming a processing mark on a glass, for example, by laser processing. That is, the laser light is concentrated in a dot shape or a line shape on the surface of the glass or in the depth direction, thereby irradiating the glass with laser light having a high energy density to form a processing mark along a predetermined line of cutting of the glass, and then along the line. The machining marks exert a mechanical force, and if so, the glass can be easily cut along the line to be cut. The processing of the glass substrate by the laser light is particularly suitable for the mechanical cutting process, in addition to shortening the manufacturing time, the glass substrate is not easily broken during processing, and is also less prone to chipping. Processing of surface tempered glass.

For example, Patent Document 2 discloses a position where a laser beam is irradiated onto a surface of a glass substrate by a wheel cutter after irradiating the glass substrate with a laser light by a YAG laser oscillating device, whereby a surface of a product such as laminated glass is used. A technique for forming cracks.

In Patent Document 3, the shape of the beam spot irradiated to the glass has an elongated shape having the largest dimension of 30 mm or more, and is scanned in a line shape on the glass, whereby cracks are generated at partial positions of the glass.

In the laser processing apparatus, in order to improve the processing speed of the object to be cut, such as glass, a laser beam is formed so that it may extend in the thickness direction of the object to be cut and the direction orthogonal to the thickness direction. The technique of modifying the interior of the object to be cut, such as glass, by a linear focus.

Conventional technical literature Patent literature

Patent Document 1: Japanese Laid-Open Patent Publication No. 2007-229831

Patent Document 2: Japanese Laid-Open Patent Publication No. 2005-104819

Patent Document 3: Japanese Laid-Open Patent Publication No. 2008-273837

Patent Document 4: Japanese Laid-Open Patent Publication No. 2008-36641

However, the techniques of Patent Documents 2 to 4 are techniques for forming a plurality of dot-shaped processing marks on a glass along a continuous linear processing mark or a linear cutting line. Therefore, when it is desired to form a processing mark of a closed shape having no end points on the glass substrate, it is necessary to continuously scan the laser light along the line to cut of the glass substrate, or to make a laser light. Since the shot position moves along the line to cut and is irradiated with laser light a plurality of times, there is a problem that the manufacturing time becomes long.

In view of the above problems, an object of the present invention is to provide a laser processing apparatus for a glass substrate which can easily form a processing mark having a closed shape without an end point on a glass substrate, and can shorten the division processing time of the glass substrate.

A laser processing apparatus for a glass substrate according to the present invention is characterized in that laser light is concentrated on a predetermined line of cut of a closed shape of a glass substrate to form a processing mark on the glass substrate, and is characterized in that it includes a laser light source. Shooting laser light; an annular cylindrical lens that corresponds to and concentrates the laser light of the laser light source on the cutting target line of the glass substrate; and a driving device that makes the irradiation area of the laser light of the laser light source relatively The cylindrical lens moves in a first direction; and a control device controls the laser light source and the driving device; and an irradiation region of the laser light emitted from the laser light source on a surface orthogonal to the optical axis thereof The width in the second direction orthogonal to the first direction is larger than the width in the second direction of the cylindrical lens; and the control device causes the irradiation region of the laser light to face the cylindrical lens by the driving device In the process of moving in one direction, the laser light source is caused to emit a plurality of laser lights.

In the above-described laser processing apparatus for a glass substrate, for example, the control device controls the irradiation region such that the irradiation region on the glass substrate irradiated with the plurality of laser beams partially overlaps the planned cutting line. At this time, the control device controls the overlap of the irradiation regions such that the energy applied to the predetermined cutting line by the irradiation of the plurality of laser beams is fixed.

In the cylindrical lens, the focal position of the laser light is placed inside the thickness direction of the glass substrate, and the depth of focus is made shorter than the thickness of the glass substrate, and it is preferably set to be 1/100 or less of the thickness of the glass substrate. Thereby, a processing mark of laser light irradiation can be formed inside the glass substrate. Therefore, it can be surely prevented because of the laser beam Irradiation and cracking on the surface.

Further, the laser processing apparatus for a glass substrate of the present invention is useful when applied to a surface-strengthened glass substrate. Surface-strengthened glass substrates, due to the hard surface characteristics, needless to say in the mechanical cutting using the cutting edge, that is, using laser cutting, when the focus position is on the surface of the glass substrate, it will also break during processing. Happening. In the present invention, since the wavelength of the laser light is 250 to 400 nm, and the focal position of the laser light by the cylindrical lens is set inside the thickness direction of the surface strengthened glass substrate, that is, the surface of the surface strengthened glass substrate The surface strengthening layer is deeper, so even if it is a surface-strengthened glass substrate, it can be prevented from being broken during processing.

The laser processing apparatus of the glass substrate of the present invention includes a ring-shaped cylindrical lens that can correspond to the laser light of the laser light source and concentrates on the line to cut of the glass substrate, and uses the moving device to make the laser light to the cylindrical lens. The irradiation area moves in the first direction. The irradiation region of the laser light emitted from the laser light source has a width in the second direction orthogonal to the first direction on the surface orthogonal to the optical axis, and a width in the second direction of the cylindrical lens is larger than the width of the cylindrical lens. In the process of moving the irradiation region of the laser light in the first direction with respect to the cylindrical lens by the driving device, the laser light of the laser light source is emitted a plurality of times. Thereby, with the movement of the irradiation region of the laser light of the cylindrical lens, a linear processing mark can be gradually formed on the glass substrate in accordance with the planned cutting line of the closed shape of the endless end of the glass substrate, and by a plurality of times The irradiation of the laser light connects the linear processing marks to form a closed shape without end points. Therefore, according to the present invention, it is possible to shorten the formation time of the processing marks and to shorten the division processing time of the glass substrate, compared to the case where the laser light is irradiated along the annular cutting line of the glass substrate.

Further, in the present invention, since the control device causes the laser light source to emit the laser light in the process of moving the irradiation region of the laser light in the first direction with respect to the cylindrical lens by the driving device, the cylindrical column is not required. a large laser light source that illuminates the laser light as a whole, and in order to make the cylindrical lens correspond to the glass substrate In the case where the shape of the predetermined line is broken and another cylindrical lens is replaced, it is not necessary to replace the laser light source.

Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. 1(a) is a plan view showing a laser light irradiation region and a processing mark formed on a glass substrate in a laser processing apparatus according to an embodiment of the present invention, and FIG. 1(b) is a perspective view showing the same as above, that is, a cylinder. Fig. 2 is a perspective view showing a cylindrical lens in a laser processing apparatus according to an embodiment of the present invention, and Fig. 3 is a perspective view showing a laser processing apparatus for a glass substrate according to an embodiment of the present invention. As shown in FIG. 3, on the stage 1, a glass substrate 2 such as a surface-strengthened glass substrate after exposure and development processing of a workpiece is placed. With respect to the stage 1, the gate-shaped moving member 3 spanning the entire area in the width direction of the stage 1 is supported so as to be reciprocable in the direction of the arrow a. Then, on the moving member 3, a support portion 4 is supported so as to be reciprocable in the width direction of the stage 1 (arrow direction b), and the support portion 4 supports the pulse laser oscillator 6. A cylindrical lens 7 provided in a ring shape is disposed above the glass substrate 2, and the pulsed laser light 5 of the pulsed laser oscillator 6 is concentrated so as to be aligned with the planned cutting line of the glass substrate 2.

In the laser processing apparatus, the glass substrate 2 such as a surface-strengthened glass substrate is placed on the stage 1, and the moving member 3 is moved in the direction of the arrow a, and the pulsed laser light 5 is intermittently emitted from the pulsed laser oscillator 6, The pulsed laser light 5 concentrated by the cylindrical lens 7 is irradiated onto the glass substrate 2. As shown in Fig. 1(a), the irradiation region of the pulsed laser light 5 has a shape such as a rectangle on a plane orthogonal to the optical axis, and the width W ₅ in the direction b is adjusted to be the same. The width W ₇ of the cylindrical lens 7 in the direction b is larger. Then, the irradiation area of the laser light 5 is adjusted so as to cover the cylindrical lens 7 in the direction b. Thereby, the laser light 5 can be irradiated to the glass substrate 2 in a line shape on the line to cut. At this time, the laser light 5 may be emitted from the pulse laser oscillator 6 while the moving member 3 is moving, or may be emitted from the pulse laser oscillator 6 in a state where the moving member 3 is temporarily stopped after the movement of the moving member 3. . The cylindrical lens 7 disposed above the glass substrate 2 can be replaced with a different focal length. Thereby, the cylindrical lens 7 having the most appropriate depth of focus can be selected in accordance with the surface characteristics of the glass substrate 2 to be processed, and the laser processing can be performed.

Further, the cylindrical lens 7 may be replaced with a shape corresponding to the planned cutting line. As shown in FIG. 1 and FIG. 2, the cylindrical lens 7 disposed above the glass substrate 2 has an annular lens having a cross-sectional shape that is uniformly convex upward, and the focal distance below it is in any cross section. Both are fixed. Therefore, in the case of the cylindrical lens 7, the line connecting the focal points thereof forms a ring shape similar to that of the annular cylindrical lens 7. In the present invention, the cylindrical lens 7 having the same shape as the annular focus of the cylindrical lens 7 is selected. In the present embodiment, the cylindrical lens 7 is arranged such that its focal point shape is a circle corresponding to a circular cutting line, and its central axis is arranged in parallel with the optical axis of the pulsed laser light 5. The cylindrical lens 7 concentrates the pulsed laser light 5 emitted from the pulsed laser oscillator 6 on the glass substrate 2. The pulsed laser light 5 has a wavelength of, for example, 250 to 400 nm, and the focal position of the cylindrical lens 7 is in the thickness direction of the glass substrate 2, and the depth of focus is set to be shorter than the thickness of the glass substrate, and is preferably set on the glass substrate. 2 is less than 1/100 of the thickness.

The laser light 5, as shown by the thin rectangular line in Fig. 1(a), is irradiated in such a manner as to cover the cylindrical lens 7 in the direction b. The irradiation timing of the laser light 5 of the pulsed laser oscillator (laser light source) 6, the moving distance of the moving member 3, and the timing of the movement are controlled by a control device (not shown).

The wavelength of the pulsed laser light 5 is, for example, 250 to 400 nm. In Fig. 5, the horizontal axis represents the wavelength, and the vertical axis represents the light transmittance of the laser light, which shows the light transmission characteristics of the surface strengthened glass. When laser light having a wavelength of 532 nm is used, the light transmittance to the glass substrate is high, that is, the energy absorption rate of the glass substrate is poor, and it is difficult to form a processing mark on the glass substrate. On the other hand, in the vicinity of the i-line (wavelength 365 nm) of the mercury lamp, absorption of energy starts, and a state in which a process mark can be formed is entered. In addition, by using a laser with a wavelength of 266 nm Light, you can get a very high energy absorption rate. Therefore, in the present invention, processing marks are formed on the glass substrate in the wavelength range of 250 to 400 nm.

In the present embodiment, the control device controls the irradiation region of the laser light 5 so that the irradiation region on the glass substrate 2 is partially overlapped on the cutting planned line by the irradiation of the plurality of laser beams 5. For example, the control device emits the laser light from the laser light source 6 so that the irradiation region of the laser light 5 of the cylindrical lens 7 overlaps with a portion of the irradiation region of the previous laser light 5. Therefore, the laser light 5 is concentrated on the circular cutting line of the glass substrate 2 corresponding to the irradiation area on the cylindrical lens 7, and the processing marks 20 (20a, 20b) are gradually formed on the glass substrate 2 by a plurality of times. The irradiation of the laser light 5 connects the linear processing marks 20 to form a circular shape.

In the present embodiment, since the laser light 5 having a rectangular shape on the surface orthogonal to the optical axis is emitted, as shown in FIG. 1(a), the irradiation region of the laser light 5 to the cylindrical lens 7 is On the surface orthogonal to the central axis of the cylindrical lens 7, when viewed from the central axis in the radial direction, all of the irradiated region 5a in the cylindrical lens 7 and a portion 5b in which a part of the cylindrical lens 7 is irradiated are generated. Therefore, the energy of the laser light input to the glass substrate 2 is larger in the region 5a than in the region 5b, and therefore, the processing mark 20a and the corresponding region 5b formed on the glass substrate 2 corresponding to the region 5a are on the glass substrate 2 The processing marks 20b formed thereon have a difference in the degree of deterioration of the glass substrate 2. The control device controls the overlap of the irradiation regions on the glass substrate 2 such that the energy applied to the cutting line by irradiation of the plurality of laser beams 5 is fixed. Thereby, the difference in the degree of deterioration of the glass substrate 2 can be eliminated. In addition, the energy input by the irradiation of the laser light 5 means the amount of heat input on the glass substrate 2.

Next, the operation of this embodiment will be described together with the control aspect of the control device. In the control device, first, as shown in FIG. 3, the cylindrical laser lens 7 disposed on the line to cut of the glass substrate 2 is moved by the moving member 3, and the pulse laser oscillator 6 is moved and disposed on the cylindrical lens 7. Above the one end side in the direction a, The laser light 5 emitted from the pulse laser oscillator 6 in a rectangular beam shape is irradiated onto the glass substrate 2. Thereby, as shown in FIG. 4(a), linear processing marks 20 (20a, 20b) are formed on the glass substrate 2 by the irradiation of the laser light 5. At this time, the energy input to the glass substrate 2 corresponding to the laser light irradiation region 5b is smaller than the energy input to the glass substrate 2 in the corresponding region 5a. Therefore, the processing mark 20b formed on the glass substrate 2 in the corresponding region 5b has a smaller degree of deterioration of the glass substrate 2 than the processing mark 20a formed in the corresponding region 5a.

Thereafter, the control device moves the pulsed laser oscillator 6 relative to the glass substrate 2 and the cylindrical lens 7 in the direction of the arrow a, as shown in FIG. 4(b), and irradiates the laser light 5 to the cylindrical lens 7. The second laser light 5 is irradiated so that the region overlaps with a part of the irradiation region of the first laser light 5 . At this time, the control device controls the laser light 5 to the cylindrical lens 7 so that the maximum energy is input to the region 5b in FIG. 4(a) in which the maximum energy is not applied to the irradiation of the first laser light 5, for example. The overlap of the illuminated areas. Thereby, the same processing mark 20a as that of FIG. 4(a) is also formed on the portion of the glass substrate 2 on which the processing mark 20b has been formed. Then, by the irradiation of the second laser light 5, the linear processing marks 20 (20a, 20b) are continuously formed on the processing marks 20a of the first irradiation. By controlling the overlapping of the irradiation areas of the laser light 5 to the cylindrical lens 7, the input energy on the line to cut can be fixed, and the processing marks 20a having the same degree of deterioration can be formed.

Thereafter, the control device similarly moves the pulsed laser oscillator 6 with respect to the glass substrate 2 and the cylindrical lens 7 in the direction of the arrow a to irradiate the area of the laser light 5 of the cylindrical lens 7 with the second laser light. The third irradiation light 5 is irradiated so that a part of the irradiation area of 5 overlaps (Fig. 4(c)). Thereby, the linear processing marks 20 (20a, 20b) are continuously formed on the processing marks 20a of the first irradiation and the second irradiation, and the irradiation of the fourth laser light 5 is performed as shown in Fig. 4(d). As shown, the linear processing marks 20 (20a, 20b) are joined to form a circular shaped mark 20a of a closed shape having no end points.

In the primary irradiation of the laser light 5, the irradiation region of the laser light 5 to the cylindrical lens 7 is generated on the surface orthogonal to the central axis of the cylindrical lens 7 when viewed from the central axis in the radial direction. In the region 5a where all of the irradiated regions 7 and the portion 5b irradiated in the cylindrical lens 7 are irradiated, the processing marks 20a and the processing marks 20b are also present due to the difference in energy density of the laser light 5 concentrated on the glass substrate 2. The degree of deterioration of the glass substrate 2 is different. However, by the control device, the laser beam is emitted from the pulsed laser oscillator (laser light source) 6 so that the irradiation region of the laser light 5 of the cylindrical lens 7 overlaps with a portion of the irradiation region of the previous laser light 5, Thereby, the difference in the degree of deterioration of the glass substrate 2 can be eliminated. In this case, it is preferable that the control device controls the processing of the glass substrate 2 by superimposing the overlapping of the irradiation regions on the glass substrate 2 so that the energy applied to the cutting line by the irradiation of the plurality of laser beams 5 is fixed. The overall deterioration of the mark 20 is equal. After the formation of the processing mark 20, for example, the bending stress can be applied by hand to break the glass substrate 2 along a circular cutting line.

In the present embodiment, as described above, by the irradiation of the plurality of laser beams 5, the same processing mark 20 as that of the endless cut line of the cut line can be formed, and the laser light 5 can be made along the glass. In the conventional laser processing method in which the annular cutting line of the substrate 2 is irradiated, the formation time of the annular processing mark 20 is short, so that the division processing time of the glass substrate 2 can be shortened.

Further, since the laser light 5 is divided into a plurality of irradiation glass substrates, a large-sized pulsed laser oscillator (laser light source) 6 that can irradiate the entire cylindrical lens 7 with the laser light 5 is not required.

For example, when laser light 5 having a wavelength of 532 nm is used, the pulse width is set to about 7 nsec, and the irradiation energy density is set to 25 J/cm ² , and the inside of the surface strengthened glass substrate 2 is irradiated with the laser light 5, the glass substrate 2 is used. Cracks will occur on the top, and the glass substrate as a whole will be divided into a mess. On the other hand, when the laser light 5 having a wavelength of 355 nm is used, the pulse width is set to about 7 nsec, and the irradiation energy density is set to 10 J/cm ² , and when the inside of the surface strengthened glass substrate 5 is irradiated with the laser light 5, The processing mark 20 can be formed inside the glass substrate 2. In this case, when the bending stress is applied to the glass substrate 2 by hand, the processing mark 20 can be beautifully broken along the circular cutting line.

Further, the focal position of the laser light 5 may be on the surface of the glass substrate. However, if the focus position of the laser light 5 is inside the glass substrate 2, it is possible to surely prevent the glass substrate 2 from being cracked. In other words, the focus position of the laser light 5 is set inside the thickness direction of the glass substrate 2, and the depth of focus is set to be shorter than the thickness of the glass substrate 2, and is preferably set to be less than 1/100 of the thickness of the glass substrate 2. Thereby, even if it is a surface-strengthened glass substrate, the reforming part of the surface can be avoided, and the energy of the laser beam 5 can be concentrated in the inside. When the glass substrate 2 is a surface-strengthened glass substrate, if the focus position of the laser light 5 is not inside the glass substrate 2, and the laser beam is concentrated in the modified portion of the surface of the surface-strengthened glass substrate, it is easy to be on the glass substrate 2. There are cluttered cracks that make the splitting situation messy. Further, when the depth of focus of the laser light 5 is equal to or greater than the thickness of the glass substrate 2, the laser light 5 reaches the back surface of the glass substrate 2, and the glass substrate 2 is broken. Therefore, the depth of focus of the laser light 5 should be shorter than the thickness of the glass substrate 2, and it is preferably within a range of 1/100 or less of the thickness of the glass substrate 2.

Further, the shape of the light beam of the laser light 5 is not limited to the rectangular shape of the above-described embodiment, and various shapes such as a circular shape and an elliptical shape may be used.

Further, in the present embodiment, the cylindrical lens 7 is described as being in a circular shape, and the cylindrical lens 7 is in a circular shape. . For example, a cylindrical lens whose plane shape is elliptical or rectangular may also be used.

Further, in the present embodiment, a description will be given of an aspect in which the processing mark 20a having a closed shape having no end point is formed by four irradiations of the laser light 5, but the number of irradiation of the laser light 5 may be, for example, 2 After three or three times, it may be five or more times.

[Industrial availability]

According to the present invention, it is easy to form a processing mark having a closed shape without an end point on the glass substrate, and the division processing time of the glass substrate can be shortened. Therefore, in the manufacturing steps of the liquid crystal display panel and the like, the glass substrate division technique is greatly contributed.

1‧‧‧ platform

2‧‧‧ glass substrate

20, 20a, 20b‧‧‧ processing marks

3‧‧‧Mobile components

4‧‧‧Support Department

5‧‧‧(pulse) laser light

5a, 5b‧‧‧ area

6‧‧‧Pulse laser oscillator (laser source)

7‧‧‧Cylindrical lens

W ₅ , W ₇ ‧ ‧ width

a, b‧‧‧ directions

Fig. 1 (a) is a plan view showing a laser beam irradiation apparatus in a laser processing apparatus according to an embodiment of the present invention, and a processing pattern formed on a glass substrate, and (b) is a perspective view of the same. It shows the cross-sectional shape of the cylindrical lens.

Fig. 2 is a perspective view showing a cylindrical lens in a laser processing apparatus for a glass substrate according to an embodiment of the present invention.

Fig. 3 is a perspective view showing a laser processing apparatus for a glass substrate according to an embodiment of the present invention.

[Fig. 4] (a) to (d) show a timing chart in which a processing mark is gradually formed on a glass substrate in accordance with the movement of the irradiation region of the laser light in the laser processing apparatus of the glass substrate according to the embodiment of the present invention. .

Fig. 5 is a view showing a light transmission characteristic of a surface-strengthened glass substrate.

2‧‧‧ glass substrate

20a, 20b‧‧‧ processing marks

5‧‧‧(pulse) laser light

5a, 5b‧‧‧ area

6‧‧‧Pulse laser oscillator (laser source)

7‧‧‧Cylindrical lens

W ₅ , W ₇ ‧ ‧ width

a, b‧‧‧ directions

Claims (5)

A laser processing apparatus for a glass substrate, which concentrates laser light on a cut-off line of a closed shape of a glass substrate having no end points to form a processing mark on the glass substrate, and is characterized by comprising: a laser light source that emits a lightning An annular cylindrical lens that corresponds to and concentrates laser light of the laser light source on the cutting line of the glass substrate; and a driving device that causes an irradiation area of the laser light of the laser light source to be opposite to the cylinder The lens moves in the first direction; and a control device controls the laser light source and the driving device; the irradiation region of the laser light emitted by the laser light source is on a surface orthogonal to the optical axis thereof, and the first direction The width of the orthogonal second direction is larger than the width of the cylindrical lens in the second direction; the control device moves the irradiation region of the laser light in the first direction with respect to the cylindrical lens by the driving device In the process, the laser source is caused to emit a plurality of laser lights. The laser processing apparatus for a glass substrate according to the first aspect of the invention, wherein the control device controls the irradiation region on the glass substrate by the plurality of laser light to partially overlap the planned cutting line Irradiation area. A laser processing apparatus for a glass substrate according to claim 2, wherein the control device controls the overlap of the irradiation regions such that the input energy of the plurality of laser beams irradiated on the cutting planned line is constant. A laser processing apparatus for a glass substrate according to any one of claims 1 to 3, wherein the cylindrical lens has a focus position of the laser light in a thickness direction of the glass substrate while setting a depth of focus It is shorter than the thickness of the glass substrate. A laser processing apparatus for a glass substrate according to claim 4, wherein the glass substrate is a surface-strengthened glass substrate, and the cylindrical lens has a focus position of the laser light set in a thickness direction of the surface-strengthened glass substrate The inside is deeper than the surface strengthening layer of the surface-strengthened glass substrate.