JP2014097908A - Chemically strengthened glass, and cutting method of chemically strengthened glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a stable scribe line without producing a crack on a chemically strengthened glass when cutting the chemically strengthened glass, and thereby to obtain the chemically strengthened glass free of a crack.SOLUTION: A cutting method of a chemically strengthened glass is a method for cutting a plate-like chemically strengthened glass G1 by folding the chemically strengthened glass G1 along a scribe line S formed thereon. The chemically strengthened glass G1 includes a chemically-strengthened effective part R, and a non-effective part N which is located next to the effective part R and of which the surface stress of at least one surface of front and rear faces is lower than that of the effective part R. A scribe line S is formed by starting the line from a starting point Y located on the one face of the non-effective part N and extending the line from the non-effective part N to the effective part R.

Description

  The present invention relates to a plate-shaped chemically tempered glass and a method for cleaving the chemically tempered glass by splitting along a scribe line formed on the plate-shaped chemically tempered glass.

  As is well known, the surface of the chemically tempered glass is reinforced by an ion exchange method (chemical strengthening treatment), and compressive stress (surface stress) is applied to the front side and the back side in the plate thickness direction. A compressive stress layer is formed. Thereby, the fracture strength with respect to the tensile stress acting on the surface layer portion is significantly increased as compared with normal glass. Such chemically tempered glass has been adopted as a cover glass for displays in smartphones, tablet PCs, and the like that are rapidly spreading in recent years.

  By the way, chemically tempered glass is very difficult to cleave unlike ordinary glass (non-tempered glass) due to the presence of a compressive stress layer formed on the surface layer portion thereof. More specifically, when cleaving normal glass, after forming the scribe line by pressing the surface of the glass with a wheel cutter or the like, by applying a tensile stress around the scribe line, along the scribe line The method of cleaving is widely used. However, when this method is applied to cleaving of chemically strengthened glass, as disclosed in Patent Documents 1 and 2, the scribe line (median crack) that is the starting point of cleaving is in a state of breaking through the compressive stress layer. There is a need to form.

WO 2011/116165 A1 WO 2012/009253 A1

  Due to this, the following problems may occur when the chemically strengthened glass is cleaved. That is, a tensile stress layer to which a tensile stress as a reaction of the compressive stress (surface stress) is applied is formed between the compressive stress layers formed on the front side and the back side in the plate thickness direction of the chemically strengthened glass. ing. Therefore, as shown in FIG. 6, when the scribe line S is formed in a state of breaking through the compressive stress layer A of the chemically strengthened glass G, the tip of the scribe line S is located in the tensile stress layer B. .

  In addition, when the formation of the scribe line S is executed, the chemically strengthened glass G is loaded with a load for forming the scribe line S. Therefore, particularly in the initial stage of the formation, the formation state is extremely poor. It becomes stable. For this reason, as shown in FIG. 7, the crack C generated from the scribe line S (median crack) due to the tensile stress applied to the tensile stress layer B is changed from the surface Ga side (scribe surface side) to the back surface in the thickness direction. Self-propelled to cross to the Gb side or self-propelled along the surface direction of the chemically strengthened glass G as shown in FIG. There was a problem.

  The present invention made in view of the above circumstances enables stable formation of a scribe line without cracking the chemically strengthened glass when cleaving the chemically strengthened glass, and chemical strengthening suitable for this purpose. Providing glass is a technical challenge.

  The method according to the present invention, which was created to solve the above-described problems, is a method of chemically tempered glass that cleaves the chemically tempered glass by splitting along a scribe line formed on the plate-like chemically tempered glass. A cleaving method, wherein the chemically tempered glass has a chemically strengthened effective portion, and the magnitude of the surface stress adjacent to the effective portion and at least one of the front and back surfaces thereof is determined in the effective portion. An ineffective portion that is smaller than the surface stress is provided, and the scribe line starts to be formed from the start end located on the one surface of the ineffective portion, and enters the effective portion from the ineffective portion. It is characterized by forming.

  According to such a method, since the scribe line starts to be formed starting from one surface of the ineffective portion whose surface stress is smaller than that of the effective portion, the initial stage of scribe line formation (non- In the formation stage in the effective portion, the formation state can be stabilized. And under this stable state, by continuously forming the scribe line from the ineffective portion to the effective portion, the stable portion can be formed in the effective portion as well as the ineffective portion. Is possible. That is, the scribe line is formed from the ineffective portion to the effective portion because the scribe line is formed from the ineffective portion to the effective portion instead of forming the scribe line starting from the effective portion. The transfer will be carried out smoothly. As a result, unreasonable force does not act on the formation of the scribe line, and the situation where the cracks generated from the scribe line (median crack) are self-propelled in the direction of the thickness of the chemically strengthened glass or in the plane direction is as much as possible. It can avoid and it can prevent that a crack arises in the said tempered glass.

  In said method, it is preferable that the magnitude | size of the surface stress in the said one surface of the said ineffective part is 0-300 MPa.

  If it does in this way, it will become possible to start forming a scribe line from the one end surface of the ineffective portion in a state where it is not substantially strengthened. For this reason, in the initial stage of the formation of the scribe line, the formation state is substantially the same as the case where the scribe line is formed on a normal plate glass (non-tempered glass). As a result, the self-running of the crack generated from the scribe line (median crack) can be avoided more effectively, and a more stable scribe line can be formed.

  In the above method, it is preferable that a difference between the magnitude of the surface stress in the effective portion and the magnitude of the surface stress on the one surface of the ineffective portion is 30 MPa or more.

  If the difference between the magnitude of the surface stress at the effective portion and the magnitude of the surface stress at one surface of the ineffective portion is 30 MPa or more, it is more advantageous in obtaining the above-described effects.

  In the above method, it is preferable that the one surface of the ineffective portion has a width of 1 mm or more from a boundary between the ineffective portion and the effective portion.

  When a scribe line is started to be formed from the edge of a chemically tempered glass by a wheel cutter or the like, cracks may develop starting from the edge and the chemically tempered glass may be broken. Therefore, it is desirable that the position away from the edge portion is the starting end of the scribe line. Therefore, if one surface of the ineffective portion has a width of 1 mm or more from the boundary between the effective portion and the ineffective portion, a position away from the edge portion can be set as the starting end of the scribe line. It is possible to effectively prevent cracking starting from the edge portion of the chemically strengthened glass.

  In the above method, it is preferable that the magnitude of the surface stress on the one surface of the ineffective portion is adjusted by performing masking, annealing, or etching on the one surface.

  By performing masking, annealing, or etching on one surface of the ineffective portion, the surface stress on the one surface can be made smaller than the surface stress on the effective portion, and stable as described above. A scribe line can be formed.

  In said method, it is preferable that the plate | board thickness of the said chemically strengthened glass is 0.3-1.8 mm.

  If the plate | board thickness of chemically strengthened glass exists in the range of 0.3-1.8 mm, it will become further advantageous in obtaining the above-mentioned effect.

  In the above method, the effective portion has a rectangular shape, and the one surface of the ineffective portion is along at least two sides continuously connected among the four sides serving as the outer peripheral ends of the effective portion. It is preferable to be provided.

  If it does in this way, one side or two or more parallel to two sides extended in the vertical direction among the four sides used as the perimeter end (contour) of the effective part to the effective part from one side of the ineffective part as the starting end Scribe lines and one or a plurality of scribe lines parallel to two sides extending in the horizontal direction perpendicular to the vertical direction can be formed. Therefore, when the chemically strengthened glass in which these scribe lines are formed is cleaved, a plurality of chemically strengthened glasses having a rectangular shape can be obtained from the effective portion after the cleaving.

  In addition, when chemically strengthened glass is cleaved by any of the above methods, cracks generated from the scribe line (median crack) at the time of forming the scribe line are automatically generated in the thickness direction or the surface direction of the chemically strengthened glass. Since it is possible to avoid running, it is possible to obtain a high-quality chemically strengthened glass without cracks.

  The chemically tempered glass according to the present invention created to solve the above-mentioned problems is a plate-shaped chemically tempered glass, which is a chemically strengthened effective portion, adjacent to the effective portion, and its front and back surfaces. Among them, the magnitude of the surface stress on at least one of the surfaces is characterized by having an ineffective portion that is smaller than the surface stress in the effective portion.

  With such a configuration, if one of the surfaces of the ineffective portion is started and a scribe line starts to be formed, and the scribe line is formed to enter the effective portion from the ineffective portion, the above chemically strengthened glass With respect to the cutting method, it is possible to enjoy the same effects as those already described. Therefore, this chemically strengthened glass can be a chemically strengthened glass capable of forming a stable scribe line.

  As described above, according to the present invention, when the scribe line is formed in the chemically strengthened glass, the crack generated from the scribe line (median crack) is free-running in the plate thickness direction or the surface direction. Since it can be avoided as much as possible, a stable scribe line can be formed. Moreover, the chemically strengthened glass suitable for achieving this purpose can be provided.

(A)-(c) is a perspective view which shows the preparation methods of the chemically strengthened glass which concerns on 1st embodiment of this invention. (A) is a top view which shows the effect | action of the cutting method of the chemically strengthened glass which concerns on 1st embodiment of this invention, (b) is a vertical side view. (A) is a top view which shows the effect | action of the cutting method of the chemically strengthened glass which concerns on 1st embodiment of this invention, (b) is a vertical side view. (A), (b) is a perspective view which shows the preparation methods of the chemically strengthened glass which concerns on 2nd embodiment of this invention. It is a top view which shows the effect | action of the cutting method of the chemically strengthened glass which concerns on 2nd embodiment of this invention. It is a side view which shows the conventional cleaving method of chemically strengthened glass. It is a side view which shows the conventional cleaving method of chemically strengthened glass. It is a top view which shows the conventional cleaving method of chemically strengthened glass.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each of the following embodiments, a case where a chemically tempered glass is prepared by immersing a plate glass in a potassium nitrate molten salt and then the chemically tempered glass is cleaved will be described as an example.

  1A to 1C are perspective views showing a method for producing chemically strengthened glass according to the first embodiment of the present invention. In this production method, first, as shown in FIG. 1 (a), masking is applied to one sheet glass G1 (manufactured by Nippon Electric Glass: CX-01) to be chemically strengthened and the front and back surfaces of the sheet glass G1. Two mask glasses G2 (manufactured by Nippon Electric Glass: CX-01) are prepared. The dimensions of the plate glass G1 and the mask glass G2 to be chemically strengthened include, for example, the plate glass G1: 200 mm × 100 mm × 0.7 mm to be strengthened and the glass G2 for mask: 100 mm × 100 mm × 0.00 mm. 7 mm can be used.

  Next, as shown in FIG. 1 (b), the two mask glasses G2 sandwich the part from one end to the center in the longitudinal direction of the glass sheet G1 to be reinforced, and the other end to the center in the direction. These are pasted together with the region G1a to be strengthened exposed. Then, the strengthened plate glass G1 and the mask glass G2 are immersed in a 400 ° C. potassium nitrate molten salt as a strengthening solution for 8 hours. Thereby, a compressive stress layer having a thickness of 23 μm and a surface stress of 600 MPa applied can be formed on the front and back surfaces of the part G1 to be chemically strengthened.

  Finally, as shown in FIG. 1C, the two mask glasses G2 are peeled off from the plate glass G1 and removed. Thereby, the chemically strengthened effective part R (cross hatched part) and the ineffective part N that is the part covered with the mask glass G2 are formed on the plate glass G1. In the present embodiment, in each of the front and back surfaces of the plate glass G1, half the area becomes the effective part R, and the remaining half area becomes the non-effective part N. That is, in the longitudinal direction of the plate glass G1, the effective portion R and the ineffective portion N each have a width of 100 mm. In this case, the ineffective portion N is in a state where no chemical strengthening is applied, that is, a state in which the surface stress applied to the front and back surfaces by the chemical strengthening is approximately 0 MPa. Through the above steps, the chemically strengthened glass G1 is produced. As will be described later, a stable scribe line can be formed on the chemically strengthened glass G1 thus manufactured.

  Here, the above manufacturing method is only an example for manufacturing chemically strengthened glass, and other methods can also be adopted. For example, the masking to the glass plate G1 to be reinforced does not react with or react with potassium nitrate molten salt, such as, for example, stainless steel fibers, metals such as stainless steel plates, silicon wafers, etc. in addition to glass. Difficult things can be used as a mask. In addition, as a strengthening liquid for performing chemical strengthening, in addition to potassium nitrate molten salt, sodium nitrate molten salt, a mixed salt of potassium nitrate and sodium nitrate, or the like can be used. In addition, it is preferable that the thickness of the plate glass G1 used as the object of reinforcement | strengthening is 0.3-1.8 mm.

  Moreover, the shape of the site | part G1a used as the chemical strengthening object can be freely formed by changing the position which masks to the plate glass G1. However, it is preferable that the non-effective part N has a width of 1 mm or more from the boundary between the effective part R and the non-effective part N regardless of the shape.

  Furthermore, in said preparation method, although it has become the aspect which strengthens both the front and back of the plate glass G1 of the reinforcement | strengthening object, you may make it chemically strengthen only one side among front and back. However, in this case, surface stress is applied only to one side, and there is a possibility that warpage occurs in the plate glass G1 due to this surface stress.

  In addition, in the manufacturing method described above, the non-effective portion N is in a state in which almost no chemical strengthening is applied, but the surface stress that is 30 MPa smaller than the value of the surface stress applied to the effective portion R. The upper limit value (for example, in the case of the above manufacturing method, 570 MPa is the upper limit value of the surface stress in the ineffective portion N with respect to 600 MPa, which is the value of the surface stress in the effective portion R). The effective part N may be chemically strengthened. In this case, after chemically strengthening the entire surface of the glass sheet G1 to be strengthened, an ineffective portion N is formed by annealing or etching a part of the entire surface, and the surface stress of the ineffective portion N is reduced. The value can be adjusted. However, since it is preferable that the non-effective portion N is substantially not chemically strengthened, it is appropriate that the surface stress value in the non-effective portion N is in the range of 0 to 300 MPa. is there. In addition, the difference in surface stress between the ineffective portion N and the effective portion R is preferably 100 MPa or more, and more preferably 200, 300, or 400 MPa or more.

  Hereinafter, the method of cleaving chemically strengthened glass will be described in detail. In the present embodiment, the case where the chemically strengthened glass G1 obtained by the above production method is cleaved in parallel with the longitudinal direction will be described as an example.

  As shown in FIG. 2A, in order to form a scribe line S that is a starting point for cleaving the chemically strengthened glass G1, the chemically strengthened glass G1 is non-stripped along a planned cutting line X extending in the longitudinal direction thereof. From the position Y on the effective portion N to the position Z on the effective portion R, the wheel cutter W of the scribe forming blade is pressed. In addition, both the position Y and the position Z are spaced apart from the edge part G1e of the chemically strengthened glass G1. Therefore, as in the case where the scribe line S is formed from the edge portion G1e, it is possible to avoid as much as possible the situation in which the crack progresses from the edge portion G1e and the chemically strengthened glass G1 breaks.

  And according to this chemical-tempered glass cleaving method, the following effects are obtained. That is, the starting end Y of the scribe line S formed on the chemically strengthened glass G1 is positioned on the ineffective portion N that is not chemically strengthened (the value of the surface stress applied by the chemical strengthening is approximately 0 MPa). Therefore, in the initial stage of formation of the scribe line S (formation stage in the ineffective portion N), the formation state is the case where the scribe line is formed with respect to a normal plate glass (non-tempered glass). It is almost the same. For this reason, the formation of the scribe line S at this stage can be made stable.

  In addition, as shown in FIG. 3A, the formation of the scribe line S continuously proceeds from the ineffective portion N to the effective portion R under this stable state. At this time, the scribe line S sequentially formed on the chemically strengthened glass G1 is formed in a state of breaking through the compressive stress layer A to which surface stress is applied, as shown in FIG. In other words, in the formed scribe line S, the tip in the thickness direction of the chemically strengthened glass G1 is located in the tensile stress layer B to which a tensile stress is applied.

  Therefore, the crack generated from the scribe line S (median crack) may be caused to self-run in the thickness direction or the surface direction of the chemically strengthened glass G1. However, since the formation of the scribe line S continuously proceeds to the effective portion R while maintaining a stable state, the effective portion R also has a stable scribe line as in the non-effective portion N. S can be formed.

  That is, the scribe line S is not formed with the effective portion R as the start end Y, but the non-effective portion N is set as the start end Y and the scribe line S is formed from the ineffective portion N toward the effective portion R. The transfer of the scribe line formation from the ineffective portion N to the effective portion R is performed smoothly. As a result, an unreasonable force does not act on the formation of the scribe line S, and the above-described fear can be eliminated as much as possible.

  And if the chemically strengthened glass G1 in which the scribe line S is formed in this way is broken by breaking along the scribe line S, a high-quality chemically strengthened glass having no cracks can be obtained by the above-described effects. Can be obtained.

  Hereinafter, a method for producing chemically tempered glass according to the second embodiment of the present invention and a method for cleaving the produced chemically tempered glass will be described.

  Fig.4 (a) is a perspective view which shows the preparation methods of the chemically strengthened glass which concerns on 2nd embodiment of this invention. This manufacturing method changes the position (position which pastes the glass G2 for masks on the plate glass G1) with respect to the plate glass G1 in the manufacturing method of the chemically strengthened glass which concerns on said 1st embodiment. . More specifically, as shown in FIG. 4B, masking is performed on the outer peripheral portion of the plate glass G1 along two continuous sides among the four sides forming the rectangular shape of the plate glass G1. In addition, it is possible to form the effective portion R having a rectangular shape and the ineffective portion N along two continuously connected sides of the four sides serving as the outer peripheral ends of the effective portion R.

  For such chemically tempered glass G1, as shown in FIG. 5, with the ineffective portion N as the starting end Y, the effective portion R is vertically out of the four sides that are the outer peripheral ends (contours) of the effective portion R. A scribe line S parallel to the two sides extending in the direction and a scribe line S parallel to the two sides extending in the lateral direction orthogonal to the vertical direction can be formed. Therefore, when the chemically strengthened glass G1 on which these scribe lines S are formed is cut, a plurality of chemically strengthened glasses having a rectangular shape can be obtained from the effective portion R after the cutting. Even in this case, it is preferable that both the start end Y and the end end Z of the scribe line S are located apart from the edge portion G1e.

  Here, the method for cleaving chemically strengthened glass according to the present invention is not limited to the aspect described in the above embodiments. For example, in each of the embodiments described above, the effective portion subjected to chemical strengthening has a rectangular shape, but the position where masking is performed on the plate glass to be strengthened, or the shape of the mask You may form in another shape by changing.

  Further, in each of the above embodiments, the end of the scribe line is located in the effective part, but it may be located in the ineffective part. In this case, for example, in the chemically strengthened glass according to the second embodiment, the ineffective portion is provided along two continuous sides among the four sides that are the outer peripheral ends of the effective portion, but on all four sides. If an ineffective portion is provided along the scribe line, both the start end and the end of the scribe line can be positioned in the ineffective portion.

  Further, the scribe line may be formed with the edge portion of the chemically strengthened glass as the start end and the end end. However, in order to prevent the occurrence of a situation in which a crack progresses from the edge portion and the chemically tempered glass is cracked, it is desirable to set the positions separated from the edge portion as the start end and the end point. In addition, although the same plate glass as the glass plate to be strengthened is used as the mask glass, a different type of plate glass may be used.

G1 chemically tempered glass (plate glass to be tempered)
G1a Reinforcement target part G1e Edge part R Effective part N Non-effective part X Cutting line S Scribe line Y Starting point of scribe line Z End of scribe line A Compressive stress layer B Tensile stress layer W Wheel cutter G2 Glass for mask

Claims (9)

By cleaving along the scribe line formed on the plate-shaped chemically tempered glass, a method of cleaving the chemically tempered glass to cleave the chemically tempered glass,
In the chemically strengthened glass, an effective part chemically strengthened,
Provided with an ineffective portion which is adjacent to the effective portion and whose surface stress on the front and back surfaces is small compared to the surface stress in the effective portion,
A method of cleaving chemically strengthened glass, characterized in that the scribe line is formed by starting from a start end located on the one surface of the ineffective portion and entering the effective portion from the ineffective portion. .   The method of cleaving chemically strengthened glass according to claim 1, wherein the magnitude of the surface stress on the one surface of the ineffective portion is 0 to 300 MPa.   3. The chemically tempered glass according to claim 1, wherein a difference between a surface stress magnitude in the effective portion and a surface stress magnitude on the one surface of the ineffective portion is 30 MPa or more. Cleaving method.   4. The chemically strengthened glass according to claim 1, wherein the one surface of the ineffective portion has a width of 1 mm or more from a boundary between the ineffective portion and the effective portion. Cleaving method.   The magnitude of the surface stress on the one surface of the ineffective portion is adjusted by performing masking, annealing, or etching on the one surface. Cleaving method of the described chemically strengthened glass.   The thickness of the said chemically strengthened glass is 0.3-1.8 mm, The cleaving method of the chemically strengthened glass in any one of Claims 1-5 characterized by the above-mentioned. The effective portion has a rectangular shape,
The said one surface of the said ineffective part is provided along the at least 2 side continuously connected among the four sides used as the outer periphery end of the said effective part, The any one of Claims 1-6 characterized by the above-mentioned. A method for cleaving chemically strengthened glass according to any one of the above.   The chemically strengthened glass cut | disconnected by the method in any one of Claims 1-7. A plate-shaped chemically strengthened glass,
A chemically enhanced effective part;
A chemical strengthening characterized by having an ineffective portion that is adjacent to the effective portion and has a surface stress on the front and back surfaces that is smaller than the surface stress in the effective portion. Glass.

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