JP2014125399A - Method for producing reinforced glass substrate for forming touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a reinforced glass substrate for a cover glass integrated touch panel with excellent productivity.SOLUTION: A method for producing a reinforced glass panel related to the embodiment 1 of this invention is a method for producing a reinforced glass substrate for forming a touch panel, with which a plurality of cover glass integrated touch panels can be formed on a sheet of the reinforced glass substrate, and comprises: a step of chemically reinforcing a rectangular glass substrate 100 with a short side length of 1,000 mm or more; a step of dividing the chemically reinforced glass substrate 100 into a plurality of reinforced glass substrates 10 with cutting; and a step of chamfering edge faces 11 of the plurality of reinforced glass substrates 10.

Description

  The present invention relates to a method for manufacturing a tempered glass substrate for a touch panel, and more particularly to a method for manufacturing a tempered glass substrate for forming a cover glass integrated touch panel.

  In mobile devices such as smartphones and tablet terminals, touch panels that are operated by touching a cover glass substrate of a display with a fingertip are widely used. FIG. 11 is a cross-sectional view of a conventional touch panel. As shown in FIG. 11, the conventional touch panel has a configuration in which a cover glass substrate 1 and a sensor glass substrate (a glass substrate on which a sensor is formed) 4 are bonded together by an optical clear adhesive (OCA) 3. have.

  A light shielding film 2 is formed on the peripheral edge of the cover glass substrate 1 made of chemically strengthened glass. On the other hand, on the sensor glass substrate 4, transparent conductive films 5a and 5b, metal wiring 6, an organic insulating layer 7, a protective layer 8, that is, a sensor is formed. Then, the light shielding film forming surface of the cover glass substrate 1 and the sensor forming surface of the sensor glass substrate 4 face each other and are bonded together by the optical transparent adhesive 3.

  In contrast, a touch panel (a so-called cover glass integrated touch panel) in which a sensor is formed on a cover glass substrate and the cover glass substrate and the sensor glass substrate are integrated has attracted attention. FIG. 12 is a cross-sectional view of the cover glass-integrated touch panel. In the cover glass-integrated touch panel shown in FIG. 12, the optical transparent adhesive 3 and the sensor glass substrate 4 in the touch panel shown in FIG. 11 are not required, and thus the thickness and weight can be reduced.

  Cutting of tempered glass is more difficult than non-tempered glass. Therefore, in the manufacturing process of the cover glass substrate 1 used for the conventional touch sensor as shown in FIG. 11, chemical strengthening is performed after cutting to the product shape. On the other hand, in the manufacturing process of the cover glass substrate 1 used for the cover glass integrated touch panel as shown in FIG. 12, from the viewpoint of improving the production efficiency, the medium glass substrate or the large glass substrate having a short side of 1000 mm or more is chemically strengthened. The light-shielding film 2, the transparent conductive films 5a and 5b, the metal wiring 6, the organic insulating layer 7, and the protective layer 8 are formed on the chemically strengthened medium- or large-sized glass substrate, and then cut into a product shape.

By the way, Patent Document 1 discloses a method of manufacturing a cover glass integrated touch panel in which a glass substrate is chemically strengthened after being cut into a product shape, the glass substrate is placed on a transport substrate, and sensor formation is performed collectively. ing.
However, rather than chemically strengthening the glass substrate after cutting to the product shape, chemical strengthening with a large glass substrate is superior in productivity.

JP 2011-197708 A

The inventor has found the following problems regarding a method for manufacturing a tempered glass substrate for forming a cover glass-integrated touch panel.
Various sizes are required for the above-described chemically strengthened medium or large glass substrates. For this reason, chemical strengthening equipment is required for each size, and there is a problem that productivity is inferior.

  This invention is made | formed in view of the above, Comprising: It aims at providing the manufacturing method of the tempered glass substrate for cover glass integrated touch-panel formation which is excellent in productivity.

The manufacturing method of the tempered glass substrate for touch panel formation which concerns on aspect 1 of this invention is a manufacturing method of the tempered glass substrate for touch panel formation which can form several cover glass integrated touch panels in one sheet | seat,
Chemically strengthening a rectangular glass substrate having a short side length of 1000 mm or more;
Dividing the chemically tempered glass substrate into a plurality of tempered glass substrates;
Chamfering the end surfaces of the plurality of tempered glass substrates. Thereby, the manufacturing method of the tempered glass substrate for cover glass integrated touch panel formation which is high in yield and excellent in productivity can be provided.

  The manufacturing method of the tempered glass substrate for touch panel formation which concerns on aspect 2 of this invention is the aspect 1 of the said invention. After the step of chemical strengthening, before the step of dividing | segmenting, the end surface damage | wound of the said glass substrate chemically strengthened is carried out. The method further includes a step of inspecting. Thereby, the manufacturing method of the tempered glass substrate for cover glass integrated touch-panel formation which is still higher in yield and excellent in productivity can be provided.

  The manufacturing method of the tempered glass substrate for touch panel formation which concerns on aspect 3 of this invention removes the said end surface damage | wound in the division | segmentation step in the aspect 2 of the said invention, when the said end surface damage | wound is detected. Thereby, the manufacturing method of the tempered glass substrate for cover glass integrated touch panel formation which is high in yield and excellent in productivity can be provided.

  The method for producing a tempered glass substrate for forming a touch panel according to aspect 4 of the present invention is the average surface roughness of the end surface of the tempered glass substrate after the chamfering step in any one of aspects 1 to 3 of the invention. Ra is 1 μm or less. Thereby, the manufacturing method of the tempered glass substrate for cover glass integrated touch-panel formation which is still higher in yield and excellent in productivity can be provided.

  The manufacturing method of the tempered glass substrate for touch panel formation which concerns on aspect 5 of this invention is a chamfering process by grinding in the step of chamfering in any one of the aspects 1-4 of the said invention. Grinding is suitable as the chamfering process.

  A method for manufacturing a tempered glass substrate for forming a touch panel according to aspect 6 of the present invention is the surface layer having residual compressive stress in the glass substrate in the step of chemically strengthening in any one of aspects 1 to 5 of the present invention. And a back surface layer and an intermediate layer having an internal residual tensile stress CT of 50 MPa or less between the front surface layer and the back surface layer.

  The manufacturing method of the tempered glass substrate for touch panel formation which concerns on aspect 7 of this invention is the cumulative fracture probability about the end surface of the said tempered glass substrate after the step which chamfers in any one of the aspects 1-6 of the said invention. The fracture stress at 0.1% is 70 MPa or more.

  The manufacturing method of the tempered glass substrate for touch panel formation which concerns on aspect 8 of this invention WHEREIN: In any one of the aspects 1-7 of the said invention, thickness t of the said tempered glass substrate shall be 0.3-1.1 mm. Is.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the tempered glass substrate for cover glass integrated touch-panel formation which is excellent in productivity can be provided.

It is sectional drawing of the cover glass integrated touch panel which concerns on the 1st Embodiment of this invention. It is sectional drawing of the tempered glass board | substrate 10 used for the cover glass board | substrate 1 which concerns on the 1st Embodiment of this invention. It is a schematic diagram which shows distribution of the residual stress of the tempered glass board | substrate 10 used for the cover glass board | substrate 1 which concerns on the 1st Embodiment of this invention. It is a flowchart for demonstrating the manufacturing method of the tempered glass substrate for cover glass integrated touch-panel formation which concerns on the 1st Embodiment of this invention. It is the figure which showed how to cut out the medium sized glass substrate (tempered glass substrate) 10 of G2 size (long side 470 mm x short side 370 mm) from the large glass substrate 100 of G6 size (long side 1850 mm x short side 1500 mm). It is a side view which shows the rotary grindstone for chamfering the end surface of the tempered glass substrate. It is a schematic top view of the large sized glass substrate in which the end surface crack generate | occur | produced in the chemical strengthening process. It is a typical top view of the large sized glass substrate in which the thermal crack which started from the end surface crack | wound occurred in the sensor formation process. It is a flowchart for demonstrating the manufacturing method of the tempered glass substrate for cover glass integrated touch-panel formation which concerns on the 2nd Embodiment of this invention. It is the figure which showed how to cut out the medium sized glass substrate (tempered glass substrate) 10 of G2 size (long side 470 mm x short side 370 mm) from the large glass substrate 100 of G6 size (long side 1850 mm x short side 1500 mm). It is a schematic diagram of a vertical placement four-point bending test apparatus. It is sectional drawing of the conventional touch panel. It is sectional drawing of a cover glass integrated touch panel.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiment. In addition, for clarity of explanation, the following description and drawings are simplified as appropriate.

(Embodiment 1)
First, a cover glass-integrated touch panel according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of a cover glass-integrated touch panel according to a first embodiment of the present invention. FIG. 1 is an inverted view of FIG. The cover glass integrated touch panel of FIG. 1 is a capacitive touch panel.

  As shown in FIG. 1, a light shielding film 2 such as a black matrix film is formed on the peripheral edge of a cover glass substrate 1 made of chemically strengthened glass. A pair of metal wirings 6 are formed on both sides of the light shielding film 2 so as not to be seen from the outside of the cover glass substrate 1 (the lower surface side of the cover glass substrate 1 in FIG. 1). The color of the light shielding film 2 is not particularly limited, and may be white, for example.

  Transparent conductive films 5 a and 5 b are formed at the center of the cover glass substrate 1. The transparent conductive film 5a extends in the x-axis direction in FIG. 1, and the transparent conductive film 5b extends in the y-axis direction in FIG. That is, the transparent conductive films 5a and 5b are extended so as to be orthogonal to each other. That is, in a plan view, the transparent conductive films 5a and 5b are formed in a lattice shape (not shown). Although only two transparent conductive films 5b are shown in FIG. 1, in practice, a large number of transparent conductive films 5a and 5b are provided. Here, as shown in FIG. 1, the transparent conductive film 5a is formed so as to straddle between the metal wirings 6 on both sides.

As shown in FIG. 1, the organic insulating layer 7 is formed between the transparent conductive films 5a and 5b in order to insulate the transparent conductive films 5a and 5b from each other.
The protective layer 8 is formed on substantially the entire surface of the cover glass substrate 1 so as to cover the light shielding film 2, the transparent conductive films 5 a and 5 b, the metal wiring 6, and the organic insulating layer 7.

  Next, the structure of the tempered glass substrate 10 used for the cover glass substrate 1 will be described with reference to FIGS. FIG. 2 is a cross-sectional view of a tempered glass substrate 10 used for the cover glass substrate 1 according to the first embodiment of the present invention. In FIG. 2, the direction of the arrow indicates the direction of action of the residual stress, and the size of the arrow indicates the magnitude of the stress. As shown in FIG. 2, the tempered glass substrate 10 includes a front surface layer 13 and a back surface layer 15, and an intermediate layer 17 provided between the front surface layer 13 and the back surface layer 15. Compressive stress remains on the front surface layer 13 and the back surface layer 15 by the following chemical strengthening method. Further, as a reaction, tensile stress remains in the intermediate layer 17.

  The tempered glass substrate 10 is produced by a chemical tempering method. As the glass for strengthening, alkali aluminosilicate glass or soda lime glass is used. In the chemical strengthening method, the front and back surfaces of glass are ion-exchanged, and ions having a small ion radius (for example, Li ions and Na ions) contained in the glass are replaced with ions having a large ion radius (for example, K ions). Thus, the front surface layer and the back surface layer in which the compressive stress remains are formed.

FIG. 3 is a schematic diagram showing a distribution of residual stress of the tempered glass substrate 10 used in the cover glass substrate 1 according to the first embodiment of the present invention.
As shown in FIG. 3, the compressive stress (> 0) remaining on the front surface layer 13 and the back surface layer 15 tends to gradually decrease from the front surface 12 and the back surface 14 of the tempered glass substrate 10 toward the inside. Further, the tensile stress (> 0) remaining in the intermediate layer 17 tends to gradually decrease from the inside of the glass toward the front surface 12 and the back surface 14.

  In FIG. 3, CS is the maximum residual compressive stress (surface compressive stress) (> 0) in the front surface layer 13 and the back surface layer 15, and CT is the internal residual tensile stress in the intermediate layer 17 (average value of residual tensile stress in the intermediate layer 17). (> 0), DOL indicates the thickness of the front surface layer 13 and the back surface layer 15, and t indicates the thickness of the tempered glass substrate 10, respectively. Therefore, the thickness of the intermediate layer 17 is t−2 × DOL.

Further, the internal residual tensile stress CT (MPa) of the tempered glass substrate is usually measured by measuring the surface compressive stress CS (MPa) and the thickness DOL (μm) of the surface layer 13 and the back surface layer 15, and the measured value and strengthening. It can be calculated from the thickness t (μm) of the glass substrate using the following formula 1.
CT = (CS × DOL) / (t−2 × DOL) Equation 1

The maximum residual compressive stress CS, the internal residual tensile stress CT, and the thickness DOL of the surface layer 13 and the back surface layer 15 can be adjusted by the strengthening process conditions. In the case of the chemical strengthening method, since the glass is immersed in a treatment liquid (for example, KNO ₃ molten salt) for ion exchange, it can be adjusted by the concentration, temperature, immersion time, etc. of the treatment liquid.

  The tempered glass substrate 10 preferably has a thickness t (mm) of 0.3 to 1.1 mm. In the case of chemically strengthened glass, when the thickness t (mm) exceeds 1.1 mm, the mass of the substrate increases, and the advantage of weight reduction by the cover glass integrated type is diminished. On the other hand, when the thickness t (mm) is less than 0.3 mm, it is difficult to perform chemical strengthening treatment on the glass. The thickness t (mm) of the tempered glass substrate 10 is more preferably 0.4 to 0.7 mm.

  By the way, the tempered glass substrate 10 for forming a cover glass-integrated touch panel according to the present embodiment is obtained by chemically strengthening a large glass substrate having a short side of 1000 mm or more, and cutting it into a plurality of pieces. . That is, the intermediate layer 17 having the internal residual tensile stress CT is exposed at the end face of the tempered glass substrate 10. Therefore, if the internal residual tensile stress CT becomes too large, cracks are likely to extend from the end face of the tempered glass substrate 10, and handling in the sensor forming process becomes difficult. Further, the larger the internal residual tensile stress CT, the more difficult the cutting itself. Therefore, the internal residual tensile stress CT is preferably 50 MPa or less. Further, the internal residual tensile stress CT is more preferably 35 MPa or less, still more preferably 30 MPa or less.

  Next, with reference to FIG. 4, the manufacturing method of the tempered glass substrate for cover glass integrated touch-panel formation which concerns on this Embodiment is demonstrated. FIG. 4 is a flowchart for explaining a method for manufacturing a tempered glass substrate for forming a cover glass-integrated touch panel according to the present embodiment. In FIG. 4, in addition to the manufacturing flow (steps S1 to S3) of the tempered glass substrate for cover glass integrated touch panel formation indicated by the solid line, the subsequent flow (steps S4 to S8) indicated by the broken line is also shown. Have been described. FIG. 4 also shows the glass substrate size in each step together with the manufacturing flow.

  First, as shown in FIG. 4, a large glass substrate having a short side with a chamfered end face of 1000 mm or more is chemically strengthened (step S1). As a large glass substrate, a so-called G6 size (long side: 1850 mm × short side: 1500 mm) having a rectangular shape can be used. Since the present invention is suitable for a large glass substrate having a short side of 1000 mm or more, a large glass substrate having a G5 size (long side 1200 mm × short side 1000 mm) may be used. Of course, as long as it is a large glass substrate having a short side of 1000 mm or more, it may be a size other than G5 and G6.

  Next, the chemically strengthened large glass substrate is cut and divided into a plurality of medium-sized glass substrates (step S2). As medium-sized glass substrates, so-called G1 size (long side 400 mm × short side 300 mm), G2 size (long side 470 mm × short side 370 mm), G3 size (long side 650 mm × short side 550 mm), G4 size (long side 880 mm × Short side of 680 mm). These sizes are due to device limitations in the sensor formation process. The medium size glass substrate is a rectangular glass substrate having a long side of less than 1000 mm, and may have a size other than the above as long as a plurality of cover glass integrated touch panels can be formed. In addition, you may test | inspect the end surface of the large sized glass substrate chemically strengthened before step S2.

  Here, a specific example of step S2 will be described with reference to FIG. FIG. 5 is a diagram showing how to cut out a medium-sized glass substrate (tempered glass substrate) 10 of G2 size (long side 470 mm × short side 370 mm) from a large glass substrate 100 of G6 size (long side 1850 mm × short side 1500 mm). It is. In FIG. 5, the cutting line is indicated by a broken line. As shown in FIG. 5, 3 × 4 = 12 tempered glass substrates 10 of G2 size (long side 470 mm × short side 370 mm) can be cut out from a large glass substrate 100 of G6 size (long side 1850 mm × short side 1500 mm). it can. Note that the hatched area in FIG. 5 is an area to be removed. In the example of FIG. 5, a region having a width of 220 mm at both ends of the long side and a region having a width of 10 mm at both ends of the short side are removed.

  As a method for cutting a chemically strengthened large glass substrate, for example, a method of introducing a scribe line on a large glass substrate with a cutter wheel and breaking it, a method of cutting by irradiating a laser beam on the large glass substrate, etc. Can be used.

  Next, the end surface of the tempered glass substrate 10 is chamfered (step S3). In this chamfering process, it is preferable to grind the entire end surface of the tempered glass substrate 10. FIG. 6 is a side view showing a rotating grindstone for chamfering the end face of the tempered glass substrate 10. In the rotating grindstone 20 shown in FIG. 6, a groove 21 having a semi-elliptical (semi-circular) cross section is formed on the side surface of the disk-shaped main body.

By pressing the end surface 11 of the tempered glass substrate 10 substantially vertically against the groove 21 of the rotating grindstone 20 rotating at high speed, the end surface 11 of the tempered glass substrate 10 is chamfered along the groove 21 of the rotating grindstone 20. It is ground together. As described above, since the intermediate layer 17 having the internal residual tensile stress CT is exposed at the end surface 11 of the tempered glass substrate 10, the surface roughness after chamfering is preferably as small as possible. Specifically, the average surface roughness Ra of the end face 11 after the chamfering process is preferably 1 μm or less. As described above, the tempered glass substrate 10 for forming the touch panel can be obtained.
In addition, after chamfering (step S3), you may further add end surface processes, such as an etching with respect to the end surface 11 of the tempered glass substrate 10, and brush grinding | polishing as needed.

Below, the sensor formation process which forms a sensor in the manufactured tempered glass board | substrate 10 is demonstrated.
First, a light shielding film such as a black matrix film is printed on a tempered glass substrate (step S4).
Next, the wiring which consists of a transparent conductive film (for example, ITO film | membrane) is formed on a tempered glass board | substrate by sputtering method (step S5). Subsequently, metal wiring is formed on the tempered glass substrate by sputtering (step S6). Thus, the touch sensor is formed on the tempered glass substrate.

Thereafter, the tempered glass substrate on which the touch sensor is formed is cut to a product shape (step S7), and the end surface of the glass substrate of each product shape is chamfered (step S8).
The cover glass integrated touch panel is obtained as described above.

  In the conventional method, since equipment for chemical strengthening is required for each size of the tempered glass substrate for forming the sensor, productivity is low. In contrast, the method for manufacturing a tempered glass substrate for forming a cover glass-integrated touch panel according to the present embodiment can cope with a single type of chemical strengthening equipment regardless of the size of the tempered glass substrate for forming a sensor. Is expensive.

(Embodiment 2)
As shown in FIG. 7A, a large glass substrate having a short side of 1000 mm or more has a long circumference and is difficult to handle in the chemical strengthening process, so that the large glass substrate and the jig are in contact with each other. As a result, scratches (also called defects) are likely to occur on the end face. Hereinafter, the scratch generated on the end face is referred to as “end face scratch”. FIG. 7A is a schematic plan view of a large glass substrate in which end face scratches have occurred in the chemical strengthening step.

  As shown in FIG. 7B, when a large glass substrate having an end face flaw is heated in a sensor forming process (for example, a sputtering process for forming transparent conductive films 5a and 5b and metal wiring 6), the end face flaw starts. Therefore, there is a risk of thermal cracking over a wide area. FIG. 7B is a schematic plan view of a large glass substrate in which thermal cracking has occurred starting from an end face flaw in the sensor formation step.

  Therefore, the large-sized glass substrate in which the end face scratch has occurred in the chemical strengthening process has not been advanced to the next process and has been disposed of. That is, the tempered glass substrate for forming the cover glass-integrated touch panel has a problem of low yield and poor productivity.

  Next, with reference to FIG. 8, the manufacturing method of the tempered glass substrate for cover glass integrated touch-panel formation which concerns on Embodiment 2 is demonstrated. FIG. 8 is a flowchart for explaining a method for manufacturing a tempered glass substrate for forming a cover glass-integrated touch panel according to the present embodiment. In FIG. 8, in addition to the manufacturing flow (steps S1 to S3, S11, S12) of the tempered glass substrate for forming a cover glass integrated touch panel indicated by a solid line, the subsequent flow (steps S4 to S8) indicated by a broken line. Is also described. FIG. 8 also shows the glass substrate size in each step together with the manufacturing flow.

  First, as shown in FIG. 8, a large glass substrate having a short side whose end face is chamfered and whose short side is 1000 mm or more is chemically strengthened (step S1). Step S1 is the same as that in FIG.

  Next, the end face of the chemically strengthened large glass substrate is inspected (step S11), and the presence or absence of an end face scratch is determined (step S12). If there is no end face scratch on the chemically strengthened large glass substrate (NO in step S12), the process proceeds to the sensor forming step (steps S4 to S6) with the G6 size (long side 1850 mm × short side 1500 mm).

  On the other hand, if there is an end face scratch on the chemically strengthened large glass substrate (step S12 YES), the large glass substrate is cut and divided into a plurality of medium glass substrates (step S2). As medium-sized glass substrates, so-called G1 size (long side 400 mm × short side 300 mm), G2 size (long side 470 mm × short side 370 mm), G3 size (long side 650 mm × short side 550 mm), G4 size (long side 880 mm × Short side of 680 mm). These sizes are due to device limitations in the sensor formation process. The medium size glass substrate is a rectangular glass substrate having a long side of less than 1000 mm, and may have a size other than the above as long as a plurality of cover glass integrated touch panels can be formed.

  Here, a specific example of step S2 will be described with reference to FIG. 9, similarly to FIG. 5, a medium-sized glass substrate (tempered glass substrate) 10 of G2 size (long side 470 mm × short side 370 mm) is cut out from a large glass substrate 100 of G6 size (long side 1850 mm × short side 1500 mm). It is the figure which showed how to cut out. In FIG. 9, the cutting line is indicated by a broken line. As shown in FIG. 9, 3 × 4 = 12 tempered glass substrates 10 of G2 size (long side 470 mm × short side 370 mm) can be cut out from a large glass substrate 100 of G6 size (long side 1850 mm × short side 1500 mm). it can.

  Here, the hatched area in FIG. 9 is an area to be removed. In the example of FIG. 9, a region having a width of 220 mm at both ends of the long side and a region having a width of 10 mm at both ends of the short side are removed. That is, the peripheral portion of the large glass substrate 100 is removed together with the end face scratch. Since the end surface scratch is a shallow scratch generated on the surface of the end surface, the end surface scratch does not adversely affect the strength of the tempered glass substrate 10 if the peripheral portion is removed by 1 mm or more. That is, thermal cracking can be effectively suppressed.

  Next, the end surface of the tempered glass substrate 10 is chamfered (step S3). Since step S3 and subsequent steps are the same as those in FIG. 4, detailed description thereof is omitted.

  Conventionally, if there is an end face scratch on a chemically strengthened large glass substrate (step S12 in FIG. 9), the large glass substrate is disposed of as a disposal. Therefore, the yield was low and the productivity was inferior. In contrast, in the method for manufacturing a tempered glass substrate for forming a cover glass-integrated touch panel according to the present embodiment, end face scratches are removed from a large glass substrate, and the adverse effects are eliminated, and then divided into a plurality of medium-sized glass substrates. To do. That is, only the periphery of the large glass substrate is disposed of. Therefore, the method for manufacturing a tempered glass substrate for forming a cover glass-integrated touch panel according to the present embodiment has dramatically improved yield and productivity as compared with the conventional method.

<End face strength survey results>
As described above, the intermediate layer 17 having the internal residual tensile stress CT is exposed at the end surface of the tempered glass substrate 10 cut from the large glass substrate 100. Therefore, the fracture stress of the end face of this tempered glass substrate 10 was investigated.

  The fracture stress at the end face was measured using a vertical 4-point bending test apparatus (Autograph AG-X manufactured by Shimadzu Corporation). FIG. 10 is a schematic diagram of a vertical four-point bending test apparatus. As shown in FIG. 10, the support portion interval = 60 mm, the load portion interval = 20 mm, and the crosshead (load portion) speed = 1 mm / min. The end face whose fracture strength is measured in the test piece shown in FIG. 10 is the lower end face supported by the support portion.

  Moreover, average surface roughness Ra of the end surface was measured about the Example and the comparative example using Mitaka Kogyo's non-contact surface shape measuring device PF60. Scanning speed = 200 μm / min and measurement distance = 4.8 mm. A Gaussian filter (cutoff 0.8 mm) was used as the filter. The roughness calculation method conformed to JIS B0601.

(Example)
With respect to the tempered glass substrate cut from the large glass substrate having a thickness t = 0.56 mm, the fracture stress at the end face was evaluated. This end face is not chemically strengthened, and is an end face where the intermediate layer having the internal residual tensile stress CT is exposed. In the example, a test piece having a width W = 70 mm and a length L = 5 mm was cut out from each of the 21 tempered glass substrates. The fracture stress was measured for these 21 samples, and the average fracture stress σ _avg was determined. Moreover, about the measurement result of the fracture stress of 21 samples, the Weibull plot based on JISR1625 was performed, and fracture stress (sigma) _B0.1 with a cumulative fracture probability of 0.1% was _{calculated |} required.
As a result, the average fracture stress σ _avg = 116 MPa, the fracture stress σ _B0.1 = 83 MPa with a cumulative fracture probability of 0.1%.
On the other hand, the average surface roughness Ra = 0.87 μm.

(Comparative example)
With respect to a large glass substrate having a thickness t = 0.56 mm which was not cut, the fracture stress of the end face having end face scratches was evaluated. This end face is chemically strengthened. In the comparative example, a test piece having a width W = 70 mm and a length L = 2 mm was cut out from each of the 20 tempered glass substrates. The fracture stress was measured for these 20 samples, and the average fracture stress σ _avg was determined. Moreover, about the measurement result of the fracture stress of 20 samples, the Weibull plot based on JISR1625 was performed, and fracture _| rupture stress (sigma) _B0.1 with a cumulative fracture probability of 0.1% was _{calculated |} required.
As a result, the average fracture stress σ _avg = 423 MPa, the fracture stress σ _B0.1 = 24 MPa with a cumulative fracture probability of 0.1%.
On the other hand, the average surface roughness Ra was 1.12 μm.

Since the intermediate layer 17 having the internal residual tensile stress CT is exposed at the end face according to the example, the average fracture stress σ _avg is smaller than that in the comparative example. However, the fracture stress σ _{B0.1 with} a cumulative fracture probability of 0.1% was three times or more that of the comparative example. It is considered that the fracture stress σ _B0.1 having a cumulative fracture probability of 0.1% is improved by removing the end face scratches.
It is preferable that the fracture stress at the cumulative fracture probability of 0.1% with respect to the end surface of the cover glass-integrated touch panel-forming tempered glass substrate is 70 MPa or more.
Moreover, about the tempered glass board | substrate which concerns on an Example, the thermal crack in a sensor formation process was not confirmed.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Cover glass substrate 2 Light shielding film 5a, 5b Transparent conductive film 6 Metal wiring 7 Organic insulating layer 8 Protective layer 10 Tempered glass substrate 11 End surface 12 Surface 13 Surface layer 14 Back surface 15 Back surface layer 17 Intermediate layer 20 Rotating grindstone 21 Groove 100 Large glass substrate

Claims (8)

A method of manufacturing a tempered glass substrate for forming a touch panel capable of forming a plurality of cover glass integrated touch panels on one sheet,
Chemically strengthening a rectangular glass substrate having a short side length of 1000 mm or more;
Dividing the chemically tempered glass substrate into a plurality of tempered glass substrates;
Chamfering the end surfaces of the plurality of tempered glass substrates, and a method of manufacturing a tempered glass substrate for forming a touch panel. After the chemical strengthening step and before the splitting step,
Further comprising the step of inspecting the edge flaw of the chemically strengthened glass substrate,
The manufacturing method of the tempered glass substrate for touchscreen formation of Claim 1. If the end face flaw is detected, in the dividing step, the end face flaw is removed;
The manufacturing method of the tempered glass substrate for touchscreen formation of Claim 2. The average surface roughness Ra of the end face of the tempered glass substrate after the chamfering step is 1 μm or less,
The manufacturing method of the tempered glass substrate for touchscreen formation as described in any one of Claims 1-3. In the step of chamfering, chamfering is performed by grinding.
The manufacturing method of the tempered glass substrate for touchscreen formation as described in any one of Claims 1-4. In the chemical strengthening step,
On the glass substrate, a surface layer and a back surface layer having a residual compressive stress, and an intermediate layer having an internal residual tensile stress CT of 50 MPa or less between the surface layer and the back surface layer are formed.
The manufacturing method of the tempered glass substrate for touchscreen formation as described in any one of Claims 1-5. The fracture stress at a cumulative fracture probability of 0.1% for the end face of the tempered glass substrate after the chamfering step is 70 MPa or more.
The manufacturing method of the tempered glass substrate for touchscreen formation as described in any one of Claims 1-6. The thickness t of the tempered glass substrate is 0.3 to 1.1 mm.
The manufacturing method of the tempered glass substrate for touchscreen formation as described in any one of Claims 1-7.

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