KR20190024648A - A method for processing an end face of a glass substrate, and a system for processing an end face of a glass substrate - Google Patents

Abstract

The present invention relates to a method for processing an end surface of a glass substrate, and a device for processing an end surface of a glass substrate. Residual stress of the glass substrate integrated with a material having low heat resistance such as resin is reduced. In addition, the residual stress can be reduced even before destruction of the glass substrate, which is usually broken within a few minutes due to high residual stress. The method for processing the end surface of the glass substrate (G) is a method for processing the end surface (20) after cutting the glass substrate (G) and comprises a melting chamfering step for melting and chamfering the end surface (20) of the glass substrate (G) and a residual stress reducing step for reducing the residual stress by heating a portion (21) near the end surface of the glass substrate (G).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for processing a glass substrate and an apparatus for processing a glass substrate,

The present invention relates to an end face of a glass substrate and an apparatus for processing an end face of the glass substrate.

In order to cut the glass substrate into product dimensions, a scribe line is formed on the glass substrate by a wheel, and the glass substrate is divided along the scribe line by bending the glass substrate (see, for example, 1).

However, residual stress remains in the scribe line due to the force applied by the wheel blade and the stress applied at the time of division. Therefore, cracks tend to occur naturally in the horizontal direction on the surface of the glass substrate, and as time elapses, cracks grow further by moisture and the like.

Further, there is known a technique of improving the strength of the cross section of a glass substrate by irradiating a laser beam to an edge (edge) of the glass substrate to perform melt surface inspection (see, for example, Patent Document 2). In this molten bevel, minute cracks on the edge of the substrate disappear, and the strength of the cross section is improved.

However, in this method, residual stress is generated in the vicinity of the molten part. The residual stress increases the possibility that the substrate is cracked. Concretely, there is a high possibility that internal defects will grow with time (later) or breakage due to subsequent flaws, and breakage may occur within several tens of minutes depending on the magnitude of the residual stress.

Patent Document 1: JP-A-6-144875 Patent Document 2: Japanese Patent No. 5245819

In view of the above, a method for reducing the residual stress on the cross section of the glass substrate has been conventionally developed. For example, in the residual stress reduction method of the glass substrate, the annealing is performed after the temperature rise. More specifically, first, the entire glass substrate is uniformly heated to a temperature equal to or higher than the glass transition point, then maintained for a predetermined time, and finally cooled slowly to room temperature. In general, a time of several hours or more is required for the heating, holding, and slow cooling steps.

This method has an advantage that the residual stress on the cross section of the glass substrate can be almost completely eliminated. In addition, there is an advantage that a plurality of glass substrates can be simultaneously processed in a furnace.

However, since the entire substrate is heated to a temperature higher than the glass transition point, it can not be applied to a glass product integrated with a material having low heat resistance such as a resin. Fig. 46 shows a glass product in which the resin materials P1 and P2 are integrally formed on the glass substrate G. Fig.

Further, since it takes more than several hours to perform the residual stress reduction processing once, it is impossible to reduce the residual stress immediately after the residual stress occurs. Therefore, it is difficult to apply the present invention to a glass substrate having a high probability of fracture within tens of minutes due to a high residual stress.

A first object of the present invention is to reduce the residual stress of a glass substrate integrated with a material having low heat resistance such as a resin.

A second object of the present invention is to make it possible to reduce the residual stress even before fracture occurs even in a glass substrate, which usually breaks down within tens of minutes due to a high residual stress.

Hereinafter, as means for solving the problems, a plurality of forms will be described. These forms can be arbitrarily combined as needed.

A method of treating an end face of a glass substrate according to one aspect of the present invention is a method of treating a cross-section after cutting a glass substrate, comprising the following steps.

◎ Fusing step by which the cross section of the glass substrate is melted.

◎ Residual stress reduction step for reducing the residual stress by heating near the end face of the glass substrate.

In this method, since the portion near the end face of the glass substrate is heated, the residual stress on the end face of the glass substrate integrated with the material having low heat resistance such as resin can be reduced. This is because the entire glass substrate is not heated, so that it is difficult for the resin and the like to be affected by heat.

In this method, since the residual stress is reduced in the heating zone (heating zone) by heating the glass substrate for about 1 to 100 seconds, even in the case of a glass substrate in which breakage usually occurs within several tens of minutes, residual stress Can be reduced.

The " portion near the end face " is a portion corresponding to the end face and the vicinity thereof.

The phrase " the portion near the end face is heated " means that there is a portion which is not heated on the center side than the vicinity of the end face.

"Reducing the residual stress" means that the growth of the internal defects is suppressed with time, and the residual stress is reduced to such an extent that the glass substrate to which no external force is applied is not split within a predetermined period of time.

The residual stress reducing means is, for example, a device capable of partial heating. Examples of the heat source for performing partial heating include a laser and various heaters.

The residual stress reducing step is started in the middle of the melting chamfering step, and both steps may be performed at the same time thereafter. Alternatively, the residual stress reducing step may be started after the melting chamfer step is completed.

The residual stress reducing step may include a laser beam scanning step of scanning the laser beam along a section in the vicinity of the end face of the glass substrate.

The residual stress reducing step may include a laser light irradiation step of irradiating laser light to each of a plurality of portions in the vicinity of the end face of the glass substrate.

In the laser light irradiation step, a plurality of laser lights may be repeatedly irradiated to a plurality of portions at the same time or in a short time.

Another aspect of the present invention is an apparatus for processing a cross section of a glass substrate after cutting the glass substrate, the apparatus comprising a molten chamfering apparatus and a residual stress reducing apparatus.

The melt chamfering apparatus melts the cross section of the glass substrate.

The residual stress reducing apparatus reduces the residual stress by heating the vicinity of the end face of the glass substrate.

In this apparatus, since the vicinity of the end face of the glass substrate is heated, the residual stress in the vicinity of the end face of the glass substrate integrated with the material having low heat resistance such as resin can be reduced. This is because the entire glass substrate is not heated, so that it is difficult for the resin and the like to be affected by heat.

In this apparatus, since the residual stress is reduced in the heating zone (heating zone) by heating the glass substrate for about 1 to 100 seconds, even in the case of a glass substrate in which breakage usually occurs within tens of minutes, residual stress Can be reduced.

In the residual stress reduction apparatus, laser light may be scanned along a section in the vicinity of the end face of the glass substrate.

The residual stress reduction apparatus may irradiate laser light to each of a plurality of portions in the vicinity of the end face of the glass substrate.

In the residual stress reduction apparatus, a plurality of laser beams may be repeatedly irradiated to a plurality of portions at the same time or in a short time.

According to the present invention, the residual stress of a glass substrate integrated with a material having low heat resistance such as a resin can be reduced.

Furthermore, according to the present invention, residual stress can be reduced even before breakage occurs in a glass substrate, which usually breaks down within tens of minutes due to a high residual stress. This is because the residual stress is reduced in the heating zone (heating zone) by heating the glass substrate for about 1 to 100 seconds.

1 is a schematic diagram of a laser irradiation apparatus according to a first embodiment of the present invention.
2 is a schematic view of a glass substrate showing the movement of a laser spot.
Fig. 3 is a cross-sectional photograph of a glass substrate melted and chamfered.
4 is a graph showing the change in retardation from the end face to the center side of the molten chamfered glass substrate.
5 is a schematic plan view showing a portion where the residual stress of the glass substrate is high.
6 is a schematic cross-sectional view showing a portion where the residual stress of the glass substrate is increased.
7 is a schematic view of a glass substrate showing the movement of the laser spot.
8 is a graph for comparing the change in retardation from the end face of the molten chamfered glass substrate toward the center side before and after the residual stress reduction treatment.
9 is a graph for comparing the change in retardation from the end face of the molten chamfered glass substrate toward the center side before and after the residual stress reduction treatment.
10 is a graph for comparing the change in retardation from the end face of the molten chamfered glass substrate toward the center side before and after the residual stress reduction treatment.
11 is a simulation result showing the temperature distribution when the scanning speed is different in the residual stress reducing process.
12 is a simulation result showing the temperature distribution when the scanning speed is different in the residual stress reducing process.
Fig. 13 is a schematic plan view showing a variation of the shape of the laser spot S when the second embodiment is carried out. Fig.
14 is a schematic plan view showing a variation of the shape of the laser spot S when the second embodiment is carried out.
15 is a schematic plan view showing variations of the shape of the laser spot S when the second embodiment is carried out.
16 is a schematic view of a glass substrate showing movement of a laser spot.
17 is a schematic view of a glass substrate showing the movement of a laser spot.
18 is a schematic view of a glass substrate showing the movement of the laser spot.
19 is a schematic view of a glass substrate showing the movement of a laser spot.
20 is a schematic view of a glass substrate showing the movement of a laser spot.
21 is a schematic view of a glass substrate showing the movement of a laser spot.
22 is a schematic view of a glass substrate showing the movement of the laser spot according to the second embodiment.
23 is a schematic view of a glass substrate showing the movement of a laser spot.
24 is a schematic view of a glass substrate showing the movement of the laser spot.
25 is a schematic view of a glass substrate showing movement of a laser spot.
26 is a schematic plan view showing an example of the order of heating positions.
27 is a schematic plan view showing an example of the order of heating positions.
28 is a schematic diagram of a laser irradiation apparatus according to a modified example of the second embodiment.
29 is a schematic view of a glass substrate showing the movement of the laser spot according to the third embodiment.
30 is a schematic view of a glass substrate showing movement of a laser spot.
31 is a schematic view of a glass substrate showing the movement of a laser spot.
32 is a schematic view of a glass substrate showing the movement of the laser spot.
33 is a schematic plan view showing variations of the intervals of the heating regions.
34 is a schematic plan view showing variations of intervals of heating zones.
35 is a schematic diagram showing a branch (branching) of a laser spot using a diffractive optical element or a transmission spatial light modulator.
36 is a schematic diagram showing the branching of a laser spot using a reflection type spatial light modulator.
37 is a schematic diagram showing beam formation by a cylindrical lens.
38 is a schematic diagram showing beam formation by a galvano scanner.
39 is a schematic diagram showing beam formation by a polygon mirror.
40 is a schematic plan view showing the positional relationship between the shielding plate and the glass substrate.
41 is a schematic front view showing the positional relationship between the shielding plate and the glass substrate.
42 is a schematic plan view of the laser irradiation apparatus of the second modification of the third embodiment.
43 is a schematic front view of the laser irradiation apparatus.
44 is a schematic diagram showing formation of three points of beams using a galvanometer scanner.
45 is a graph showing changes in the laser pulse and the angle of the light ray with respect to time;
46 is a schematic plan view of a conventional glass product integrated with a material having low heat resistance.

1. First Embodiment

(1) Laser Irradiation Apparatus

Fig. 1 shows the overall configuration of a laser irradiation apparatus 1 according to an embodiment of the present invention. 1 is a schematic diagram of a laser irradiation apparatus according to a first embodiment of the present invention.

The laser irradiation apparatus 1 has a function of melting the end face of the glass substrate G and a method of reducing the residual stress in the vicinity of the end face by heating the vicinity of the end face of the glass substrate G Function.

The glass substrate G includes glass only and glass in combination with other members such as resin. Representative examples of the glass type include soda glass and non-alkali glass used for displays, instrument panels and the like, but the types are not limited thereto. Specifically, the thickness of the glass is not more than 3 mm, for example, in the range of 0.004 to 3 mm, and preferably in the range of 0.2 to 0.4 mm.

The section near the section refers to a section and its vicinity, and includes a section near the edge of the outer edge and a section near the edge of the hole.

The laser irradiation apparatus 1 is provided with a laser apparatus 3. The laser apparatus 3 has a laser oscillator 15 and a laser control unit 17 for irradiating the glass substrate G with a laser beam. The laser control unit 17 can control the driving of the laser oscillator 15 and the laser power.

The laser apparatus 3 has a transfer optical system 5 for transferring the laser light to a mechanical drive measurement described later. The transmission optical system 5 has, for example, a condenser lens 19, a plurality of mirrors (not shown), a prism (not shown), and the like.

The laser irradiation apparatus 1 has a drive mechanism 11 for changing the size of the spot of the laser beam by moving the position of the lens in the direction of the optical axis.

The laser irradiation apparatus 1 has a processing table 7 on which a glass substrate G is placed. The machining table 7 is moved by the table drive unit 13. The table drive unit 13 has a moving device (not shown) that moves the machining table 7 in a horizontal direction with respect to a head (not shown). The moving device is a known device having a guide rail, a motor, and the like.

The laser irradiation apparatus 1 is provided with a control section 9. The controller 9 includes a processor (for example, a CPU), a storage device (for example, ROM, RAM, HDD, SSD, etc.), various interfaces (for example, an A / D converter, Communication interface, etc.). The control unit 9 performs various control operations by executing a program stored in a storage unit (corresponding to a part or all of the storage area of the storage device).

The control unit 9 may be constituted by a single processor, but it may be constituted by a plurality of independent processors for each control.

The control unit 9 can control the laser control unit 17. The control unit 9 can control the driving mechanism 11. [ The control unit 9 can control the table driving unit 13. [

A sensor for detecting the size, shape and position of the glass substrate G, a sensor and a switch for detecting the state of each device, and an information input device are connected to the control unit 9, though not shown.

(2) Melting chamfer operation

The operation of taking the cross-section of the glass substrate G in the molten plane will be described with reference to Figs. 2 to 4. Fig. 2 is a schematic view of a glass substrate showing the movement of a laser spot. Fig. 3 is a cross-sectional photograph of a glass substrate which is melted and chamfered. 4 is a graph showing the change in retardation from the end face to the center side of the glass substrate melted and chamfered.

First, the glass substrate G is set at a predetermined position on the machining table 7.

Next, as shown in Fig. 2, a laser beam is irradiated onto the glass substrate G in the vicinity of the end face 21 of the glass substrate G, and the laser spot S is irradiated onto the glass substrate G, As shown in FIG. At this time, the laser spot S is set so as to be, for example, 10 to 150 占 퐉 away from the end face 20 of the glass substrate G toward the inside of the substrate (central side).

By irradiating and scanning the laser spot S as described above, the portion 21 near the end face of the glass substrate G is heated. In particular, by irradiating the laser light of the intermediate infrared light (middle infrared light), the laser light is transmitted to the inside of the glass substrate G and absorbed. The cross section 20 of the glass substrate G is relatively uniformly heated not only on the surface side irradiated with the laser beam but also on the entire inside and back side of the glass substrate G. [ Therefore, the cross section 20 of the glass substrate G is melted so that the central portion of the substrate thickness swells outward. As a result, the cross section 20 is chamfered as shown in Fig.

However, the method of melt-shearing is not particularly limited. As another example, a laser beam is irradiated from both or one of the front and back surfaces of the glass substrate G and laser light is irradiated from a direction orthogonal to the cross section 20 of the glass substrate G, It is also possible to perform chamfering by melting the cross section 20 of the gaps G. It is also possible to irradiate the laser light of the original external light.

As a result, as shown in Fig. 4, the retardation (nm) becomes high in the vicinity of the end face of the glass substrate G (for example, in the region of 200 탆 from the end face 20). The retardation is a phase difference produced in light transmitted through an object, and is a value proportional to the stress acting in the object. When the retardation of an object to which no external force is applied is high, it means that the residual stress is high.

(3) Residual stress reduction treatment

5 to 7, the residual stress reducing process for heating the portion near the end face of the glass substrate G will be described. 5 is a schematic plan view showing a portion where the residual stress of the glass substrate is increased. 6 is a schematic cross-sectional view showing a portion where the residual stress of the glass substrate is increased. 7 is a schematic view of a glass substrate showing the movement of a laser spot.

7, laser light is irradiated onto the glass substrate G on the machining table 7 to the vicinity of the end face 21 of the glass substrate G and the laser spot S is irradiated onto the glass substrate G, (21) near the end face of the projection (G). Here, the section near the section 21 corresponds to the residual stress generating zone Z (slanted area) where the residual stress is generated by the molten chamfering.

At this time, the size of the laser spot S is set smaller than that of the glass substrate G, for example, about 4 to 20 mm. As a result, the portion 21 near the end face of the glass substrate G is heated by the laser spot S.

The present inventors have found that, in the residual stress reduction treatment, it is necessary to suppress the high temperature region to a narrow range in the direction along the cross section 20, leading to the present invention. The reason will be described later. That is, the scanning speed of the laser spot S is set to be slow, and the glass substrate G is heated to a temperature equal to or higher than the glass transition point. As a result, the high temperature region does not spread in the direction along the cross section 20, and therefore, the effect of reducing the residual stress is enhanced. Conversely, setting the scanning speed quickly increases the power required to heat to a temperature above the glass transition point. If the high-power laser spot S is scanned at a high speed, the high-temperature region spreads in the direction along the cross section 20, so that the effect of reducing the residual stress is low.

The scanning speed may be 20 mm / s or less, preferably 10 mm / s or less, and more preferably 5 mm / s or less.

As a result, the portion 21 in the vicinity of the end face of the glass substrate G (i.e., the residual stress generating region Z) is heated to the glass transition point or higher, and as a result, the residual stress is reduced.

In this method, the glass substrate G, which is formed integrally with a material having a low heat resistance such as a resin, is heated since the portion near the end face 21 of the glass substrate G is heated (i.e., the entire glass substrate G is not heated) It is possible to reduce the residual stress of the portion 21 in the vicinity of the end face. This is because heat is hardly affected by resin. In addition, if the area of the residual stress generating region Z is not extremely wide, the residual stress reducing process can be completed within several tens of minutes, and even in the case of a glass substrate in which fracture usually occurs within tens of minutes due to a high residual stress, The residual stress can be reduced.

The kind (wavelength) of the laser is not particularly limited.

The required laser output is an output capable of heating the glass substrate G to a glass transition point or higher. For this reason, when a laser having a low light absorptivity to glass is used, a higher laser output is required.

The heat source is not limited to a laser, and may be, for example, an infrared heater or a contact heater.

Further, when the temperature of the heating portion of the glass substrate G is about the glass transition point, the deformation of the heating portion is hardly confirmed. When the temperature of the heating part is higher, the heating part melts and the shape changes. The higher the laser output, the lower the viscosity of the heating section, and it is greatly deformed in a short time. According to the present invention, even when the shape of the glass substrate G is deformed due to a high laser output, the residual stress is reduced. However, when the present invention is applied to a product having an allowable deformation amount of the glass substrate (G), the upper limit of the laser output is set so that the viscosity of the glass substrate (G) Should be set.

The direction of heat input to the glass substrate G is not particularly limited. It may be heat input from the surface of the glass substrate G, may be heat input from the back surface, and may be heat input from the end surface 20. Fig.

In the above embodiment, the residual stress reduction process is performed after the completion of the melt chamfering. However, the melt chamfering process and the residual stress reduction process may be performed in parallel on one glass substrate (G). Concretely, the residual stress reduction process is started during the melt chamfer operation by using two laser beams, and thereafter both processes are performed at the same time. In this case, the total processing time is shortened.

In order to use a plurality of laser beams, a plurality of laser oscillators may be prepared, and the laser beam may be branched from one laser oscillator.

(4) Experimental Example

Experimental examples of residual stress reduction processing by laser scanning will be described with reference to Figs. 8 to 10. Fig. Figs. 8 to 10 are graphs for comparing the change in retardation from the end face to the center side of the glass substrate (non-alkali glass having a thickness of 200 mu m) melted and chamfered before and after the residual stress reduction treatment.

The residual stress can be reduced by an extraordinary laser (Er fiber laser) or an extraordinary laser (CO ₂ laser). The Er fiber laser is characterized by a wavelength of 2.8 μm, a maximum output of 10 W, a light absorption rate of about 30%, and a substantial incident heat of 3 W at maximum. The CO ₂ laser is characterized by a wavelength of 10.6 μm, a maximum output of 250 W, a light absorption rate of about 80%, and a substantial heat input of 200 W at maximum.

(4-1) First Experimental Example

In the first heating (melt sawing) in Fig. 8, an Er fiber laser was used, and the spot size was 200 μm, 5 W, and 3 mm / s.

In the second heating (residual stress reduction processing) in Fig. 8, an Er fiber laser was used, and the substrate subjected to melt face sawing under the above conditions was heated under the conditions of spot sizes 2 mm, 4 W, and 0.2 mm / s.

As is apparent from Fig. 8, the maximum value of the residual stress is greatly reduced.

(4-2) Example 2

In the first heating (melt face inspection) in Fig. 9, an Er fiber laser was used, and the spot size was 200 μm, 5 W, and 3 mm / s.

In the second heating (residual stress reduction processing) in Fig. 9, an Er fiber laser was used, and the substrate subjected to molten chamfering under the above conditions was heated under the conditions of spot sizes of 1 mm, 3.5 W, and 1 mm / s. As is apparent from Fig. 9, the maximum value of the residual stress is reduced.

8 and 9, the probability that the molten chamfered glass substrate was spontaneously cleaved within a few minutes to several days was high before the residual stress reduction treatment was performed. However, after performing the residual stress reduction treatment, It did not break even after months. In the residual stress reduction treatment, the power density of the laser light is adjusted so that the glass is melted and the shape does not change. That is, the residual stress is reduced without changing the shape of the cross-section of the molten chamfered glass substrate, and the probability that the glass substrate spontaneously cracks is reduced.

(4-3) Experimental Example 3

In the first heating (melt face inspection) in Fig. 10, an Er fiber laser was used, and the spot size was 200 μm, 5 W, and 3 mm / s.

In the second heating (residual stress reduction processing) in Fig. 10, an Er fiber laser was used, and the substrate subjected to melting face-shearing under the above conditions was heated under conditions of spot size of 0.4 mm, 4 mm / s, and laser output of 4 to 6 W . In the case of the laser output of 4W, no change was observed in the residual stress generated in the first heating (melting sawing). This is because the laser output is low and the temperature of the glass substrate G does not exceed the glass transition point. In the case of the laser output of 5.5 W, the maximum value of the residual stress was slightly reduced. In addition, the residual stress was significantly increased in a part of the region where the residual stress was low due to the first heating (melt face inspection). In the case of the laser output of 6 W, as a result of the high laser output, the glass substrate G melted and deformed. Even if the laser output is set high until the glass substrate is melted and deformed, the residual stress caused by the first heating (melting sawing) is hardly reduced, and a part of the region where the residual stress is low due to the first heating The residual stress was greatly increased.

As can be seen from Fig. 10, in this experimental example, the residual stress reduction effect was low even when the laser output was adjusted.

(4-4) Consideration

As described above, the scanning speed of the second heating (residual stress reduction processing) was 0.2 mm / s for the first experimental example and 1 mm / s for the second experimental example, and good results were obtained. However, as can be seen from the comparison of the graphs, the faster the scanning speed, the lower the residual stress reducing effect. In the third experimental example, as the scanning speed was set to 4 mm / s faster, the residual stress was hardly reduced. From the above, in the case of the laser scanning method of the present embodiment, it is preferable that the scanning speed is slow. Specifically, the scanning speed may be 20 mm / s or less, preferably 10 mm / s or less, and more preferably 5 mm / s or less.

The present inventors have found that it is necessary to suppress the high temperature region to a narrow range in the direction along the cross section 20 in the residual stress reduction processing based on the experiment and the temperature simulation of the glass substrate, . This basis is explained, for example, by FIGS. 11 and 12. FIG. Figs. 11 and 12 are simulation results showing the temperature distribution when the scanning speed is different in the residual stress reducing process. Fig.

11 shows a case where the scanning speed of the laser spot S is as low as 0.2 mm / s and the residual stress reducing effect is high. Since the scanning speed is set to be slow, the high temperature portion (for example, an area exceeding 300 캜) is not elongated along the cross section.

On the other hand, Fig. 12 shows a case where the scanning speed is as high as 20 mm / s and the residual stress reducing effect is low. However, the laser output is set to be high so as to be heated to the same level as in Fig. Compared with Fig. 11, it can be seen that the high temperature portion is elongated along the cross section.

These results are one of the reasons for the decrease in the residual stress reducing effect when the high temperature portion is elongated along the cross section.

In addition, a second experimental example according to the second embodiment described later also shows a rationale for the present invention. In the second experimental example, instead of scanning the laser spot S along the section near the section 21, one point in the section near the section 21 is heated for a predetermined time to reduce the residual stress in the heated area . Figs. 13, 14 and 15 are schematic plan views showing variations of the shape of the laser spot S when the second embodiment is carried out. Fig.

13 shows a circular laser spot S100 and an elliptic laser spot S101 in a direction orthogonal to the end face 20. In Fig. In Fig. 14, long oval laser spots (S102, S103) are shown along the cross section 20. 15 shows a laser spot S104 of a long shape along the cross section 20 covering the entire cross section 20. As shown in Fig. When the laser spots S100, S101, S102 and S103 are used, the residual stress in the heating region is reduced by adjusting the laser output and the predetermined time for heating. However, the residual stress reducing effect was high in the order of S100? S101? S102? S103. In the case of using the laser spot S104, even if the laser output and the predetermined time for heating were adjusted, the residual stress was not reduced.

In view of the above-described simulation results and experimental results, the inventors of the present invention found that it is necessary to suppress the high temperature region to a narrow range in the direction along the cross section 20 in the residual stress reduction treatment, It came.

(5) First Modification

In the first embodiment, the single beam scanning process for reducing the residual stress on one side of the glass substrate G has been described. However, it is also possible to perform the multiple beam scanning process for irradiating a plurality of portions in the vicinity of the end face of the glass substrate with laser light, It is also possible to simultaneously reduce the residual stress on the sides.

16 to 18, such an embodiment will be described as a first modification. 16 to 18 are schematic views of a glass substrate showing the movement of the laser spot.

As shown in Fig. 16, the residual stress generating region Z is the portion 21 near the end face, which is the fourth variant of the glass substrate G.

As shown in Fig. 17, four laser spots S scan four sides.

As a result, as shown in Fig. 18, the residual stress of the glass substrate G is reduced. In this case, the processing time is shorter than that of the single beam scanning processing. The number of laser spots may be 2, 3, 5 or more.

(6) Second Modification

In the first embodiment, the glass substrate G is rectangular and has a plurality of straight sides, but the present invention can also be applied to a glass substrate G having curved sides or the like.

19 to 21, such an embodiment will be described as a second modification. 19 to 21 are schematic views of a glass substrate showing the movement of a laser spot.

As shown in Fig. 19, the glass substrate G is circular, and the portion near the end face 21, which is the entire outer peripheral edge, is the residual stress generating region Z. As shown in Fig.

As shown in Fig. 20, four laser spots S are scanned in the circumferential direction at four positions on the outer peripheral edge. As a modification, the glass substrate G may be rotated.

As a result, as shown in Fig. 21, the residual stress of the glass substrate G is reduced.

The number of laser spots may be 2, 3, 5 or more. The same method can also be applied to the case where the portion near the end face of the edge of the hole of the glass substrate G having the circular hole is formed as the residual stress generating region Z. [

2. Second Embodiment

(1) Basic principle

In the first embodiment, the laser beam is scanned on the end face as the residual stress reduction processing, but the method of irradiating the laser beam is not limited to this.

22 to 25, another irradiation method of the laser beam will be described as the second embodiment. 22 to 25 are schematic views of a glass substrate showing movement of the laser spot according to the second embodiment. The basic configuration and basic operation of the laser irradiation apparatus are the same as those of the first embodiment.

In Fig. 22, the laser spot S1 is irradiated onto one point (point) of the portion near the end face 21.

In Fig. 23, the laser spot S2 is irradiated to another point at another position in the section-near portion 21.

In Fig. 24, the laser spot S3 is irradiated to another point at another position in the section-near portion 21.

In Fig. 25, the laser spot S4 is irradiated to another point at another position in the section-near portion 21.

When the laser spot is irradiated to a point on the residual stress generating zone Z only for a predetermined time and heated to a temperature equal to or higher than the glass transition point, the residual stress in the region is reduced. 22 to 25, by successively heating one point for a predetermined time, the laser spots S1 to S4 are successively irradiated to adjacent positions in the cross-sectional direction, and as a result, The portion 21 is irradiated as a whole.

However, the number of laser spots, the position, the order of irradiation, and the proportion of the laser spots in the vicinity of the end face 21 are not limited to this embodiment.

In this embodiment, one point is heated for a predetermined time, the position is shifted, and one point is heated for a predetermined time, so that the residual stress generating region Z is set to a temperature equal to or higher than the glass transition point, (21).

In this embodiment, the laser spot S is finally irradiated to the entire portion near the end face 21 to lower the residual stress of the entire portion 21 in the vicinity of the end face. However, when the residual stress is lowered only in a part of the section near the section 21, the laser spot S may be irradiated only to a specific one of the sections near the section 21, It is okay to investigate only the area of

The predetermined time for heating depends on the temperature of the heating zone (heating zone) during heating. That is, the higher the temperature is, the higher the temperature of the heating zone becomes, and the residual stress is reduced in a short time. The higher the output is, the shorter the time required for heating and the shorter the tact time.

The predetermined time for heating is preferably, for example, about 1 picosecond to 100 seconds. The minimum predetermined time is 1 picosecond, which is known as the minimum value of the time (relaxation time) required to relax the structure of the glass. When the temperature of the heating zone is low, the relaxation time becomes longer. When the temperature of the heating zone is about the glass transition point, the predetermined time for heating is preferably set to about 100 seconds as the relaxation time.

In order to make the predetermined time for heating extremely short, it is necessary to heat the glass substrate G to a high temperature in a short time, and the required output increases greatly. Therefore, in practical use, The heating conditions are determined by the balance of the increase in the cost due to the heating.

In the case of a circular shape, the laser spot S is preferably, for example, 4 mu m to 20 mm in diameter. In this second embodiment, the larger the diameter of the laser spot S is, the wider the processing area per heating and the shorter the time required to reduce the residual stress of a predetermined area. As shown in Figs. 13 and 14, the laser spot S may be an elliptical shape. However, as the width of the laser spot S in the direction along the cross section 20 is longer than the width of the laser spot S in the direction intersecting the cross section 20, the residual stress reducing effect decreases. The width of the laser spot S along the cross section 20 is preferably 10 times or less the width of the laser spot S in the direction crossing the cross section 20. [

The laser output needs to be a value that can be heated to a glass transition point or higher. This is properly set depending on the size of the laser spot, the wavelength of the laser, the kind of the glass, and the thickness of the plate. When the temperature of the heating part is high, the heating part melts and the shape changes. According to the present invention, even when the shape of the glass substrate G is deformed due to a high laser output, the residual stress is reduced. However, when the present invention is applied to a product having an allowable deformation amount of the glass substrate (G), the upper limit of the laser output is set so that the viscosity of the glass substrate (G) Should be set.

An example of the condition of heating for a predetermined time for an alkali-free glass having a thickness of 200 mu m will be described. Using a CO ₂ laser (wavelength of 10.6 mu m) having a spot size of 4 mm, it is 3 W and 2 s. 4W, and 4s. 6W, and 2s.

The heat source is not limited to a laser. For example, an infrared heater or a contact heater may be used.

(2) Irradiation method of laser spot

In the case where the above-described heating method for a predetermined time is performed while being displaced from the position, heating is carried out for a predetermined time sequentially by heating for the first time, heating for the second time after the heating is not performed, and heating for the third time. At this time, in order to shorten the tact time, it is necessary to shorten the time interval between the heating operations. However, for example, in the order of the heating positions shown in Fig. 26, a region adjacent to the immediately preceding heating region is the next heating region. In this case, for example, in the second heating, it is necessary to wait until the temperature of the first heating portion lowers. The reason is that, for example, the second heating region is combined with the first heating region to correspond to the case where the high temperature portion becomes longer along the section in the case of heating the portion near the end face of the glass substrate G .

(2-1) First method

As a first method for shortening the time interval between heating operations in the case of conducting the above-mentioned uneven heating, there is a heating position order designing method. Specifically, in this method, as shown in Fig. 27, the region adjacent to the immediately preceding heating region is skipped, and the region separated is defined as the next heating region.

(2-2) Second method

As a second method for shortening the time interval between the heating operations, there is a method of cooling the substrate. 28 shows a substrate cooling apparatus 35 for cooling the substrate by jet air from the front side or the rear side of the glass substrate G. As shown in Fig. 28 is a schematic view of a laser irradiation apparatus according to a modified example of the second embodiment.

In this case, the first heating region is cooled by air cooling or the like, and then the second heating is performed. Thus, even in the case of heating in the order shown in Fig. 26, the time interval can be shortened.

The reason why the time interval can be shortened as described above is that since the next laser beam is irradiated after the heated portion irradiated with the laser beam is cooled, even if the next laser beam is irradiated near the heated portion, Is not spread in the direction along the end face by cooling. That is, this case corresponds to "the case where the high temperature portion is narrowly suppressed along the cross section in the case of heating the portion near the end face of the glass substrate G".

The cooling medium for cooling is not particularly limited.

The substrate cooling apparatus may be realized by making the table on which the glass is placed a water-cooled table.

The substrate cooling mechanism may be mounted on the laser irradiation apparatus 1. [

3. Third Embodiment

In the heating method for the predetermined time in the second embodiment, a one-point heating method of laser-irradiating each point is employed, but laser irradiation may be conducted at the same time.

29 to 32, such an example will be described as a third embodiment. In this multi-point coincidence method, the actual processing speed is increased. 29 to 32 are schematic views of a glass substrate showing the movement of the laser spot according to the third embodiment.

In Fig. 29, the two laser spots S1 are irradiated on the near-end face portion 21.

Fig. 30 shows a situation in which the residual stress is reduced in the portion near the end face 21 by the operation of Fig.

In Fig. 31, two laser spots S2 are irradiated on the portion near the end face 21. At this time, the two laser spots S2 are irradiated while being displaced from each other, i.e., in a position different from that of the two laser spots S1. In addition, the two laser spots S2 correspond to the remaining residual stress generating region (Z).

In Fig. 32, the residual stress is reduced in the portion near the end face 21 by the operation of Fig. 31.

In the multi-point simultaneous heating system, when the number of heating zones is n, the output is n times as high as that of the one-point heating system of the second embodiment. In the shielding method described later, a higher output is required depending on the area of the shielding portion.

The heating conditions per one point are the same as those in the second embodiment.

The interval between the heating zones is preferably 0.5 times or more the width of one heating zone. If the distance between the heating zones is too narrow, a plurality of heating stations are connected and become the same as irradiating one long laser spot along the cross section 20. That is, in accordance with the above-described " case where the high temperature part is elongated along the end face in the case of heating the vicinity of the end face of the glass substrate G ", the residual stress reducing effect becomes low. Fig. 33 and Fig. 34 show the variation of the shape and the interval of the heating area. Fig. 33 and Fig. 34 are schematic plan views showing the variation of the shape and the interval of the heating region.

In Fig. 33, a three-point circular laser spot S105 is shown. The laser spot S105 has the same shape as the laser spot S100 shown in Fig. 13 and has a high residual stress reducing effect. The interval of the laser spot S105 is set to be approximately equal to the width of the laser spot S105.

In Fig. 34, three laser spots (S106) of long elliptical shape in the direction crossing the cross section 20 are shown. The laser spot S106 has the same shape as the laser spot S101 of FIG. 13 and has a high residual stress reducing effect. The interval of the laser spot S106 is set to be approximately equal to the width of the laser spot S106.

The combination of the shape and the interval of the laser spot is many other than the above.

The processing speed of the residual stress reduction processing changes depending on the number of heating regions. For example, in a case where the width of the heating zone is 8 mm, the ten points simultaneous heating, the heating time is 1 s, and the residual stress reduction width per heating area is 4 mm, the processing speed per irradiation is 4 mm x 10 / s = 40 mm / s .

35 and 36, a method of performing simultaneous multi-point heating using an optical branching device will be described. 35 is a schematic diagram showing the branching of a laser spot using a diffractive optical element or a transmission spatial light modulator. 36 is a schematic diagram showing the branching of a laser spot using a reflective spatial light modulator.

In Fig. 35, a diffractive optical element (DOE) 31 or a transmission spatial light modulator (SLM) 31 is shown.

In Fig. 36, a reflective spatial light modulator (SLM) 33 is shown. Two mirrors 34 are also shown.

When the multi-point simultaneous heating method as shown in Figs. 29 to 32 is carried out while displacing the position, the first heating is performed, the second heating is performed, the third heating is performed, and the heating is performed for a predetermined time in this order All. At this time, in order to shorten the tact time, it is necessary to shorten the time interval between the heating operations. However, for example, when any one of the second heating regions at a plurality of locations becomes a region adjacent to any one of the first heating regions at a plurality of locations, the second heating is performed at a temperature It is necessary to wait until it is lowered. The reason is that, for example, the second heating region is combined with the first heating region to correspond to the case where the high temperature portion becomes longer along the section in the case of heating the portion near the end face of the glass substrate G .

In the first method for shortening the time interval between the heating operations, the time interval can be shortened by devising the heating position sequence so that the second heating region is located at a position away from the first heating region in the above case.

As a second method for shortening the time interval between the heating operations, there is a method of cooling the substrate. In this method, as shown in Fig. 28 of the second embodiment, the substrate cooling apparatus 35 for cooling the substrate by the jet air from the table side or the side of the glass substrate G is used. In this case, the first heating area is cooled by air cooling or the like, and then the second heating is performed. Thus, for example, even if the second heating region becomes the region adjacent to the first heating region, the time interval can be shortened.

The reason why the time interval can be shortened as described above is that since the next laser beam is irradiated after the heated portion irradiated with the laser beam is cooled, even if the next laser beam is irradiated near the heated portion, Is not spread in the direction along the cross section due to cooling. That is, this case corresponds to the case where the above-described " high temperature part is narrowly suppressed along the end face in the case of heating the vicinity of the end face of the glass substrate G ".

Cooling may be performed all the time, or may be performed after laser light irradiation.

As in the second embodiment, the configuration of the cooling device, the cooling means, and the arrangement position are not particularly limited.

(1) First Modification

37 to 41, a method of performing simultaneous multi-point heating in a shielding manner will be described. 37 is a schematic diagram showing beam formation by a cylindrical lens. 38 is a schematic diagram showing beam formation by a galvano scanner. Fig. 39 is a schematic diagram showing beam formation by a polygon mirror. Fig. 40 is a schematic plan view showing the positional relationship between the shielding plate and the glass substrate. 41 is a schematic front view showing the positional relationship between the shielding plate and the glass substrate.

An elongated beam along the cross section 20 is formed by a cylindrical lens 41 (Fig. 37), a galvanometer scanner 43 (Fig. 38), a polygon mirror 45 (Fig.

40 and 41, a plurality of laser spots S are formed by partially shielding the laser beam B by using the shielding plate 47. As shown in Fig. The shielding plate 47 has a plurality of shielding portions 47a disposed with a gap in the cross-sectional direction.

It is necessary for the shielding plate 47 to reflect or absorb the laser light. In the case of absorption, it is necessary to have heat resistance. It is necessary to provide a forced cooling mechanism for the shielding plate when it absorbs laser light but does not have sufficient heat resistance.

It is also possible that a mechanism (not shown) for moving the shielding plate 47 along the section near the end face 21 of the glass substrate G may be provided. In this case, the positions of the plurality of laser spots S can be changed, and by repeating this, it is possible to irradiate the laser spot S on the whole of the end face portion 21.

(2) Second Modification

42 to 45, a method of performing simultaneous multi-point heating in such a manner that laser light is scanned by one pulse will be described. 42 is a schematic plan view of the laser irradiation apparatus of the second modification of the third embodiment. 43 is a schematic front view of the laser irradiation apparatus. 44 is a schematic diagram showing the formation of three laser spots using the galvanometer scanner 43. Fig. 45 is a graph showing changes in laser pulse and angle of light with respect to time;

42 and 43, the laser irradiation apparatus 1A has a laser oscillator 15, a beam expander 49, a condenser lens 19, and a galvanometer scanner 43. The laser irradiation apparatus 1A controls the irradiating position of the laser beam by one pulse using the galvanometer scanner 43 and irradiates the laser beam at a plurality of points pseudo simultaneously , But they are irradiated substantially simultaneously) to make a state in which multiple points are heated at the same time.

In the example of Fig. 44, the position of the laser spot moves on the sample surface by 10 mm by changing the angle of the laser beam by 1 degree with the galvanometer scanner 43. As shown in FIG. 45, when the angle of the light beam is changed in synchronization with the laser pulse oscillating at 500 Hz, the laser beam travels one 20-millimeter region in a cycle of 12 milliseconds, and each of the three laser spots has one cycle (12 milliseconds) Laser light is irradiated only for 2 milliseconds. In addition, no laser beam is irradiated to the region between the three laser spots. In this case, since the period during which the laser beam is scanned is sufficiently fast, if this operation is repeated for a predetermined time (for example, one second), three points are heated simultaneously for a predetermined time.

In the second modification, a substrate cooling apparatus 35 is provided as shown in Fig. However, the substrate cooling apparatus may be omitted.

4. Other Embodiments

While the present invention has been described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications may be made without departing from the scope of the invention. In particular, a plurality of embodiments and modifications written in this specification may be arbitrarily combined as needed.

[Industrial Availability]

INDUSTRIAL APPLICABILITY The present invention can be widely applied to an end face processing method of a glass substrate and an end face processing apparatus of a glass substrate.

1: laser irradiation device 3: laser device
5: Transmission optical system 7: Machining table
9: control unit 11: driving mechanism
13: table driving part 15: laser oscillator
17: laser control unit 19: condenser lens
20: cross-section 21:
35: Substrate cooling device 41: Cylindrical lens
43: galvano scanner 45: polygon mirror
47: shielding plate G: glass substrate
S: Laser spot Z: Residual stress generating area

Claims (8)

As a method of treating the end face after cutting the glass substrate,
A molten chamfering step for molten chamfering the cross section of the glass substrate,
And a residual stress reducing step of heating the portion near the end face of the glass substrate to reduce the residual stress. The method according to claim 1,
Wherein the residual stress reducing step has a laser beam scanning step of scanning a portion near the end face of the glass substrate along the cross section with a laser beam scanning step. The method according to claim 1,
Wherein the residual stress reducing step includes a laser light irradiation step of irradiating laser light to each of a plurality of portions of the glass substrate near the end face. The method of claim 3,
Wherein the laser beam irradiation step repeatedly irradiates a plurality of laser beams to the plurality of locations simultaneously or in a short time. An apparatus for processing a cross section of a glass substrate after cutting,
A molten chamfering device for taking an end face of the glass substrate into a molten face,
And a residual stress reducing device for heating the portion near the end face of the glass substrate to reduce the residual stress. The method of claim 5,
Wherein the residual stress reducing apparatus scans a portion near the end face of the glass substrate along the end face with laser light. The method of claim 5,
Wherein the residual stress reducing apparatus irradiates laser light to each of a plurality of portions in the vicinity of an end face of the glass substrate. The method of claim 7,
Wherein the residual stress reducing apparatus repeatedly irradiates a plurality of laser beams to the plurality of locations simultaneously or in a short time.

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