Chemically strengthened glass plates, manufacturing methods for strengthened glass plates, and glass plates

Abstract

In a chemically strengthened glass plate (12) with a thickness of 0.1 mm or less, which has an overall warped shape or a partially warped portion, when the glass plate (12) is placed on a horizontal surface with one of its main surfaces (12a) facing upwards, the position of the glass plate (12) with the highest height above the horizontal surface is designated as the first peak position (D1), and the portion of the glass plate (12) with a width of 10 mm along its periphery is designated as the periphery portion (12e), the first peak position (D1) exists in the portion of the glass plate (12) that is more inward than the periphery portion (12e).

Description

Technical Field

[0001] This invention relates to a chemically strengthened glass plate (an ion-exchangeable glass plate), a method for manufacturing a strengthened glass plate from the glass plate, and the glass plate itself. Background Technology

[0002] In recent years, there has been a trend towards larger screen sizes in portable electronic devices such as smartphones and tablets. However, increasing screen size leads to a larger overall device size and reduces portability. Therefore, foldable devices have been proposed to balance large screens with good portability.

[0003] In order to be able to bend, the cover glass used in such a foldable device needs to be thinner than before, for example, using an ultra-thin type of reinforced glass sheet as disclosed in Patent Document 1. This reinforced glass sheet is manufactured from an ultra-thin type of chemically reinforced glass sheet (for example, with a thickness of 0.1 mm or less) that serves as its raw material.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-188360 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, the chemically strengthened glass sheets described above undergo various manufacturing processes before becoming strengthened glass sheets, including a cleaning process to clean their surface and a cutting process to cut them to product dimensions. During this process, the glass sheet's deflection increases due to its thinness. The deflection of the glass sheet is inversely proportional to the square of its thickness; therefore, when the thickness is 0.1 mm or less, further when the thickness is 0.05 mm or less, and further when the thickness is 0.04 mm or less, the deflection becomes more pronounced, making handling and transportation difficult. Here, the thinner the strengthened glass sheet is, the greater the difference in thickness between the glass accumulation portion at the width-direction end of the glass strip and the effective portion (including the portion that later becomes the product) in the forming process of the chemically strengthened glass sheet that becomes its raw material. Therefore, when manufacturing an ultra-thin glass plate with a uniform thickness across the entire width of the effective portion, wavy, discontinuous warping can easily occur near both ends of the effective portion's width direction during adjustments to forming conditions such as temperature distribution. This makes it difficult to manufacture a flat glass plate with uniform thickness and minimal warping. Furthermore, the glass plate is prone to breakage during the manufacturing process due to warping present during or after forming.

[0009] Here is an example of a case where an ultra-thin chemically strengthened glass sheet breaks. For instance, a chemically strengthened glass sheet supplied to the cover glass of a foldable device is suitable for forming by an overflow pull-down method. In this case, because the glass sheet is formed continuously, after the melting, forming, and annealing processes, there are glass accumulation portions with relatively large thicknesses at both ends in the width direction of the glass strip. Then, the non-effective portions (parts that are discarded and not considered part of the product) including these glass accumulation portions are cut off and removed by cutting methods such as diamond scribing or laser scribing, leaving the aforementioned effective portions with relatively uniform thickness. However, if warping exists near both ends in the width direction of the effective portion as described above, there is a possibility that the scribing is not uniform when cutting off the non-effective portions, causing unintentional breakage of the effective portions.

[0010] Another example of breakage of ultra-thin chemically strengthened glass plates is as follows: when a glass plate cut from a glass strip is adsorbed or placed on a smooth plate such as a platform, and then cut to the desired size, breakage occurs starting from the part that is not adsorbed locally due to warping (the floating part). Furthermore, as another example, during the handling and cleaning of the chemically strengthened glass plate, additional warping due to the superposition of the glass plate's deflection causes the glass plate to become stuck in the cleaning brush, transport roller, or the end face of the glass plate to sag into the gap between adjacent transport rollers, resulting in breakage.

[0011] In view of the above, the technical problem to be solved is to minimize breakage during the manufacturing process caused by warping in glass sheets, including ultra-thin chemically strengthened glass sheets.

[0012] Solution for solving the problem

[0013] The inventor, after in-depth research, obtained the following insights (A) and (B).

[0014] (A) In ultra-thin chemically strengthened glass plates with a thickness of less than 0.1 mm, it is extremely difficult to prevent warping.

[0015] (B) Although it is impossible to prevent the occurrence of warping itself, if the position of the warping with the highest height from the horizontal plane (the warping that protrudes the most upward) of the warping contained in the glass plate is set at the position where it separates from the periphery of the glass plate inward, the breakage of the glass plate during the manufacturing process can be minimized.

[0016] Based on the above insights, the glass plate used to solve the above problems is a chemically strengthened glass plate with a thickness of 0.1 mm or less and including warping, characterized in that, under the provisions of (1) to (8) below, the position of the first peak exists in a portion of the glass plate that is closer to the periphery.

[0017] (1) Let the thickness of the glass plate be t [mm].

[0018] (2) In the case of a first placement method in which the glass plate is placed on a horizontal surface with one of the main surfaces facing upward, the position of the glass plate at its highest point above the horizontal surface is set as the first peak position.

[0019] (3) Let the height of the glass plate at the first peak position above the horizontal plane be W. 1MAX [mm].

[0020] (4) In the case of a second placement method in which the glass plate is placed on a horizontal surface with the other main surface located on the back side of one main surface as the top, the position of the glass plate at the highest height from the horizontal surface is set as the second peak position.

[0021] (5) Let the height of the glass plate at the second peak position above the horizontal plane be W. 2MAX [mm].

[0022] (6) The portion of the glass plate with a width of 10mm along its perimeter is defined as the perimeter.

[0023] (7) When the first mounting method is adopted, the height of the position with the highest height from the horizontal plane in the periphery is set as W. 1OUT [mm].

[0024] (8) When the second mounting method is adopted, the height of the position with the highest height from the horizontal plane at the periphery is set as W. 2OUT [mm].

[0025] In this glass plate, the first peak position is located in a portion of the glass plate that is closer to the periphery. The first peak position corresponds to the top of the highest warp (the most upwardly protruding warp) in the glass plate, which is the highest in height from the horizontal plane, in the first mounting configuration. Therefore, when the first peak position is located in a portion closer to the periphery, the location of the warp with the highest height from the horizontal plane is a position where it separates from the periphery of the glass plate inwards. Thus, according to this glass plate, breakage of the glass plate during the manufacturing process can be minimized. It should be noted that, as another aspect of the invention, for example, a portion of the glass plate with a width of 20 mm along its periphery can be defined as the periphery portion, or a portion with a width of 30 mm can be defined as the periphery portion. When changing the width of the periphery portion in this way, it is preferable that the width of the periphery portion of the glass plate is, for example, in the range of 10 mm to 50 mm.

[0026] In the aforementioned glass plates, it is preferable that t satisfies 2 / W 1OUT A relationship greater than 0.005. Furthermore, it is preferable to satisfy W. 1OUT The relationship is ≤0.20mm. Furthermore, preferably, it also satisfies W. 1OUT The relationship is / t<5.

[0027] The inventor's in-depth research resulted in the following insight (C).

[0028] (C) Regarding the warping present in the peripheral portion under the first mounting method, the higher the height above the horizontal plane (the upward protrusion dimension), the more likely the glass plate will break during the manufacturing process. That is, W 1OUT The higher the value, the easier it is for the glass plate to break.

[0029] Furthermore, the thinner the glass sheet, the easier it is for the periphery to flex during manufacturing, making the glass more prone to breakage. It should be noted that the degree of flex is inversely proportional to the square of the glass sheet's thickness. Based on the above, in W... 1OUT The smaller the value and the value of t, t 2 The smaller the value of W 1OUT The smaller the value, the more advantageous it is in preventing glass breakage. Furthermore, if the above relationship is satisfied, glass breakage can be prevented more effectively.

[0030] In the aforementioned glass plates, it is preferable that W satisfies... 1MAX The relationship is / t<15.

[0031] To avoid breakage, the thinner the glass plate, the more... 1MAXIt is advantageous to have a smaller value (equivalent to the height of the highest warped top above the horizontal plane in the first mounting configuration). Furthermore, if the above relationship is satisfied, breakage of the glass sheet can be further appropriately avoided. Additionally, if the above relationship is satisfied, it is also suitable for subsequent processes in manufacturing tempered glass sheets from this glass sheet, such as supplying the glass sheet to various post-processing steps including lamination, cutting into individual pieces, grinding the peripheral end faces, and chemical treatment. Reducing the overall warping of the chemically tempered glass sheet is also advantageous in preventing warping, unevenness, or other deformations exceeding permissible limits from occurring in the tempered glass sheet manufactured from this glass sheet.

[0032] In the aforementioned glass plates, one main surface and the other main surface may be forged surfaces. That is, it is also possible to have glass plates that have not undergone surface and back grinding treatments (e.g., thinning treatments or chemical grinding treatments to reduce thickness) after forming. It should be noted that there are also methods that use glass-corroding chemicals such as hydrofluoric acid to chemically thin (reduce plate thickness) relatively thick glass plates (e.g., exceeding 0.1 mm to 0.4 mm) to obtain ultra-thin chemically strengthened glass plates. In this case, uniform thickness reduction during the thinning process is difficult, and the uniformity of the thickness of the obtained glass plate is hard to obtain. Therefore, the thickness deviation of the obtained glass plate becomes larger, or warping occurs. Such thickness deviations and warping further amplify warping in subsequent strengthening processes, causing surface unevenness. Therefore, the method of directly forming ultra-thin chemically strengthened glass plates is very suitable in terms of obtaining flatter glass plates.

[0033] In the aforementioned glass sheet, the thickness can be 0.05 mm or less. Furthermore, the glass sheet can have a substantially uniform thickness throughout. Even with such an extremely thin glass sheet, breakage during the manufacturing process can be minimized.

[0034] In the aforementioned glass plate, it is preferable that the second peak is located in a portion of the glass plate that is closer to the inner side than the periphery.

[0035] As described above, if not only the first peak position exists in the portion of the glass plate that is closer to the periphery, but the second peak position also exists in the inner portion, it is further advantageous in preventing breakage of the glass plate during the manufacturing process. In this case, for example, it is further advantageous in preventing situations where the periphery, which droops between adjacent transport rollers, gets caught on the transport rollers when the glass plate is transported using transport rollers.

[0036] In the aforementioned glass plates, it is preferable that t satisfies 2 / W 2OUTA relationship greater than 0.005. Furthermore, preferably, W satisfies... 2OUT The relationship is ≤0.20mm. Furthermore, preferably, it satisfies W. 2OUT The relationship is / t < 5. In addition, it is preferable to satisfy W. 2MAX The relationship is / t<15.

[0037] If we assume that these relations are satisfied, then as already described, according to the explanation, it is preferable to satisfy t. 2 / W 1OUT >0.005, W 1OUT ≤0.20mm, W 1OUT / t<5 and W 1MAX The same reasoning applies to the relationship where / t<15, which can further appropriately prevent glass plate breakage.

[0038] In the aforementioned glass plate, the glass plate may also be aluminosilicate glass, which, as a glass composition, contains 50-80% SiO2, 5-25% Al2O3, 0-15% B2O3, 1-20% Na2O, and 0-10% K2O by mass%.

[0039] In the aforementioned glass plate, the glass plate may also be aluminosilicate glass, which, as a glass composition, contains 60-80% SiO2, 8-20% Al2O3, 0-5% B2O3, 4-16% Na2O, and 0.01-10% K2O by mass%.

[0040] In the aforementioned glass plate, it may also be rectangular, with dimensions ranging from 150mm×150mm to 1100mm×1300mm.

[0041] The effect of the glass plate described above (the effect of minimizing breakage) is not only obtained in the cutting process after forming, the cleaning process, and the handling of the glass plate in these processes, but also in processes such as cutting the desired size before chemical strengthening to obtain the cover glass for foldable equipment, the film forming process, or the stacking of the glass plate, grinding the edge end face of the periphery with a single piece, or the post-processing process of chemical treatment.

[0042] The chemically strengthened glass plate of the present invention can include a portion in which warped peaks are not present, particularly near the corners, in the peripheral portion. Specifically, another aspect of the chemically strengthened glass plate of the present invention is a chemically strengthened glass plate with a thickness of 0.1 mm or less. Preferably, the glass plate has an overall warped shape or has partially warped portions. When the glass plate is placed on a horizontal surface with one of its main surfaces facing upwards, the position of the glass plate at its highest point above the horizontal surface is designated as the first peak position. The first peak position exists outside a region of the glass plate with a radius of 10 mm from the corner.

[0043] In this structure, it is preferable that, in the case of a second placement method in which the glass plate is placed on the horizontal plane with the other main surface located on the back side of the one main surface facing upwards, the position of the glass plate at its highest height from the horizontal plane is designated as the second peak position, and the second peak position exists outside the area of ​​the glass plate with a radius of 10 mm from the corner.

[0044] Furthermore, the method for manufacturing the reinforced glass sheet of the present invention includes a preparation step of preparing the aforementioned chemically reinforced glass sheet, a cutting step of cutting a product-sized glass sheet from the glass sheet, and a strengthening step of obtaining the reinforced glass sheet by chemically strengthening the product-sized glass sheet. According to this method for manufacturing the reinforced glass sheet, it is easy to prevent warping exceeding permissible limits in the manufactured reinforced glass sheet.

[0045] Furthermore, the present invention can also be applied to glass plates other than those used for chemical strengthening. That is, the glass plate other than the chemically strengthened glass plate is characterized by having a thickness of 0.1 mm or less, having an overall warped shape or having partially warped portions, and when the glass plate is placed on a horizontal surface with one of its main surfaces facing upwards in a first mounting manner, the position of the glass plate with the highest height from the horizontal surface is designated as the first peak position, and the portion of the glass plate with a width of 10 mm along its periphery is designated as the periphery portion. In this case, the first peak position exists in the portion of the glass plate that is more inward than the periphery portion.

[0046] In this glass plate, it is also possible that, in the case of a second placement method in which the glass plate is placed on the horizontal plane with the other main surface located on the back side of the one main surface facing upwards, the second peak position exists in the part of the glass plate that is more inward than the periphery when the position at which the glass plate is at its highest height from the horizontal plane is set as the second peak position.

[0047] It should be noted that the other structures and properties of these glass plates, besides those used for chemical strengthening, are the same as those of the chemically strengthened glass plates already described. Therefore, the glass plates described here can also be used as chemically strengthened glass plates.

[0048] Invention Effects

[0049] The glass plate according to the present invention, including the chemically strengthened glass plate, can minimize breakage during the manufacturing process caused by warping. Attached Figure Description

[0050] Figure 1 This is a cross-sectional view showing the preparation process in the manufacturing method of tempered glass sheet.

[0051] Figure 2 This is a cross-sectional view showing the preparation process in the manufacturing method of tempered glass sheet.

[0052] Figure 3 This is a top view showing a glass plate used for chemical strengthening.

[0053] Figure 4 This is a top view showing a glass plate used for chemical strengthening.

[0054] Figure 5 This is a graph showing the distribution of warping when Y=105 in the case of the first mounting method in Example 5.

[0055] Figure 6 This is a diagram showing the warping distribution under the first mounting method in Example 14.

[0056] Figure 7 This is a graph showing the distribution of warping when Y=55 in the case of the first mounting method in Example 14.

[0057] Figure 8 This is a diagram showing the warping distribution when the second mounting method is adopted in Example 14.

[0058] Figure 9 This is a diagram showing the warping distribution under the first mounting method in Example 15.

[0059] Figure 10 This is a diagram showing the warping distribution when the second mounting method is adopted in Example 15.

[0060] Figure 11 This is a diagram showing the warping distribution under the first mounting method in Example 16.

[0061] Figure 12 This is a diagram showing the warping distribution when the second mounting method is adopted in Example 16.

[0062] Figure 13 This is a diagram showing the warping distribution under the first mounting method in Example 17.

[0063] Figure 14 This is a diagram showing the warping distribution when the second mounting method is adopted in Example 17.

[0064] Figure 15 This is a diagram showing the warping distribution under the first mounting method in Example 18.

[0065] Figure 16 This is a diagram showing the warping distribution when the second mounting method is adopted in Example 18.

[0066] Figure 17 This is a graph showing the warping distribution when the first mounting method is adopted in Comparative Example 4.

[0067] Figure 18 This is a graph showing the warping distribution when the second mounting method is adopted in Comparative Example 4.

[0068] Figure 19 This is a diagram showing the warping distribution under the first mounting method in Example 19.

[0069] Figure 20 This is a diagram showing the warping distribution when the second mounting method is adopted in Example 19. Detailed Implementation

[0070] Hereinafter, the chemically strengthened glass plate and the manufacturing method of the strengthened glass plate according to the embodiments will be described with reference to the accompanying drawings.

[0071] The manufacturing method of tempered glass sheet includes: a preparation step, which prepares a glass sheet for chemical strengthening; a cutting step, which cuts a glass sheet of product size from the prepared glass sheet; and a strengthening step, which obtains a tempered glass sheet by chemically strengthening the cut glass sheet of product size.

[0072] [Preparation Process]

[0073] The chemically strengthened glass sheet of this embodiment is manufactured by known forming methods accompanying sheet drawing, such as overflow drawing, slit drawing, redrawing, and float glass. In the overflow drawing method, since the front and back surfaces of the formed glass strip do not contact any part of the formed body during the forming process, it has the advantage of producing a very smooth forged surface with a very flat surface property achieved through appropriate temperature control. Especially in ultra-thin strengthened glass sheets, damage to the glass surface during bending can become the starting point of failure; therefore, the overflow drawing method is most suitable as a forming method that minimizes damage through non-contact. In this embodiment, a glass strip is formed using the overflow drawing method, and a rectangular glass sheet of a specified size is obtained by cutting from the glass strip. The preparation process includes... Figure 1 as well as Figure 2 The forming process P1, annealing process P2, cooling process P3, and cutting process (not shown in the diagram) are shown.

[0074] In the preparation process, firstly, by using... Figure 1 as well as Figure 2 The manufacturing apparatus 1 shown performs forming process P1 to cooling process P3 to obtain a strip glass film 2, which is used as a raw material for chemically strengthened glass plates.

[0075] Forming process P1 is performed in forming zone ZN1. In forming process P1, a glass strip 5 is continuously formed from molten glass 4 using a forming body 3 for overflow pull method. The forming body 3 is housed in a forming furnace 6, which is equipped with a heating device (e.g., a flat plate heater) for heating the forming body 3.

[0076] The forming body 3 has: a groove 3a for allowing molten glass 4 to flow in; a pair of side portions 3b, 3b for allowing molten glass 4 overflowing from the groove 3a to flow down to both sides respectively; and a lower end portion 3c for fusing (merging) the molten glass 4 flowing down along each side portion 3b. A glass strip 5 is formed from the molten glass 4 fused at the lower end portion 3c using this forming body 3.

[0077] Glass strip 5 has a property existing in its width direction (in Figure 1 The center represents the left and right directions. Figure 2 The effective portion 5a is located in the center (vertically perpendicular to the paper surface), and the ineffective portions 5b are located at both ends in the width direction, sandwiched between the effective portion 5a. The effective portion 5a is the part that will become the product, and the ineffective portion 5b is the part that will not become the product and will be discarded. In the ineffective portion 5b at the width direction end of the glass strip 5, a glass accumulation portion (also called an ear) with a thicker wall than other portions is formed at the portion corresponding to the width direction end edge (edge) of the glass strip 5.

[0078] The glass strip 5 after it has been formed uses an edge roller 7 (cooling roller) located directly below the forming body 3 to suppress shrinkage in the width direction.

[0079] A pair of edge rollers 7 are arranged in the thickness direction, separated by the glass strip 5. Each of the pair of edge rollers 7, 7 has a shaft 7a extending in the width direction of the glass strip 5, and a first roller 7b and a second roller 7c connected to each other via the shaft 7a. The two rollers 7b, 7c are made of heat-resistant material (e.g., platinum, platinum alloy) and are in contact with the non-effective portion 5b of the glass strip 5. By using the first rollers 7b, 7b and the second rollers 7c, 7c of this pair of edge rollers 7, 7 to clamp the glass strip 5 in the thickness direction, the glass strip 5 is fed downward while suppressing shrinkage in the width direction.

[0080] Annealing process P2 is performed in annealing zone ZN2. In annealing process P2, the glass ribbon 5, which has descended from forming zone ZN1, is guided downwards while being annealed to a temperature below the strain point. Annealing furnace 8 and annealing rollers 9 configured as multiple sections (five sections in the example) are used in the execution of annealing process P2.

[0081] Annealing furnace 8 is positioned below forming furnace 6. Annealing furnace 8 is equipped with a heating device (e.g., a flat plate heater), which is not shown in the diagram, for adjusting the temperature of the atmosphere within the furnace. For example, in the case of a chemically strengthened glass plate, it is preferable to install a heating device, heat-insulating member, etc., in the region between a temperature lower than the softening point (e.g., 860°C) and the strain point (e.g., 560°C) to apply a temperature gradient along the width direction of the glass plate and to allow for temperature adjustment within this temperature range. Furthermore, in the annealing process P2, particularly in the initial stage of the annealing process P2 where the glass strip 5 has a relatively high temperature, the annealing speed is relatively faster closer to the ends in the width direction (closer to the glass accumulation area), and relatively slower closer to the center in the width direction. Specifically, for example, the annealing process P2 is performed at a cooling rate of 1–10°C / second in the center and 3–20°C / second at the ends. Therefore, regarding the glass plate obtained from the subsequent cutting process (see...), Figure 3 as well as Figure 4 This can suppress warping of the periphery of the glass plate.

[0082] In each of the multiple segments, a pair of annealing rollers 9 are arranged in the thickness direction, separated by the glass strip 5. Each pair of annealing rollers 9, 9 has a shaft 9a extending along the width direction of the glass strip 5, and a first roller 9b and a second roller 9c connected to each other via the shaft 9a. The two rollers 9b, 9c are made of ceramic as an example, and both can contact the non-effective portion 5b of the glass strip 5. The glass strip 5 is guided downward by the first rollers 9b, 9b and the second rollers 9c, 9c of this pair of annealing rollers 9, 9.

[0083] Here, the first rollers 9b and 9c do not clamp the glass strip 5 from both sides of the back, but only restrict the oscillation of the glass strip 5 along the thickness direction. That is, gaps are formed between the first roller 9b and the glass strip 5, and between the second roller 9c and the glass strip 5.

[0084] It should be noted that, as another method for suppressing warping of the periphery of the glass sheet obtained by the cutting process, there is also a method in the annealing furnace 8 where the non-effective portion 5b of the glass strip 5 is clamped from both sides of the surface and back by annealing rollers 9, and the tension acting on the glass strip 5 in the width direction is varied. For example, if the tension acting on the width direction of the glass strip 5 is increased, warping at both ends of the glass strip 5, especially the effective portion 5a, in the width direction can be suppressed. As a result, warping of the periphery of the glass sheet can be suppressed.

[0085] Cooling process P3 is performed in cooling zone ZN3. In cooling process P3, the glass ribbon 5, which has passed through annealing zone ZN2, is cooled while being pulled downwards by support roller 10. Support roller 10 is disposed in cooling chamber 11 located below annealing furnace 8.

[0086] A pair of support rollers 10 are arranged in the thickness direction, separated by the glass strip 5. Each pair of support rollers 10 has a shaft 10a extending in the width direction of the glass strip 5, and a first roller 10b and a second roller 10c connected to each other via the shaft 10a. The two rollers 10b and 10c are made of rubber as an example, and both are in contact with the non-effective portion 5b of the glass strip 5. The glass strip 5 is clamped and pulled in the thickness direction by the first rollers 10b and 10b and the second rollers 10c and 10c of this pair of support rollers 10, thereby determining the transport speed V1 (pulling speed) of the glass strip 5. The glass strip 5, which passes through the cooling zone ZN3 along with the transport, is obtained as a strip glass film 2.

[0087] Once the cooling process P3 is completed, the cutting process will proceed.

[0088] In the cutting process, a first cut is performed to cut the glass film substrate from the strip glass film 2, and a second cut is performed to cut the chemically strengthened glass substrate from the glass film substrate.

[0089] In the first cutting, the strip glass film 2 is repeatedly cut to a predetermined length (cutting along the width direction) to continuously cut out glass film plates from the strip glass film 2. It should be noted that each cut glass film plate includes an effective portion 5a and non-effective portions 5b sandwiched in the middle and existing on both sides. In the second cutting, the effective portion 5a is cut out as a glass plate for chemical strengthening by breaking off each glass film plate and removing the non-effective portions 5b. The first and second cutting can be performed using known methods, therefore detailed descriptions are omitted.

[0090] It should be noted that in this embodiment, the non-effective portion 5b of the strip glass film 2 is broken and removed after the original glass film is cut out. However, it is not limited to this. As another method, after the non-effective portion 5b of the strip glass film 2 is continuously broken and removed, the strip glass film 2 after the non-effective portion 5b has been removed is repeatedly cut (cut along the width direction) to a predetermined length, thereby continuously cutting out the chemically strengthened glass plate from the strip glass film 2.

[0091] Alternatively, the following method can be used: after continuously breaking and removing the non-effective portion of the strip glass film 2, the strip glass film 2 is continuously wound into a roll with a strip buffer (such as a resin-made strip protective sheet). In this case, in subsequent processes, the strip glass film 2 is unwound from the roll at the desired length each time, and the unwound strip glass film 2 is cut to produce a glass plate for chemical strengthening. Therefore, the extraction efficiency of the glass plate for chemical strengthening is improved, i.e., the cost is reduced. It should be noted that when using this method, the end-face treatments such as grinding, heat treatment, and etching described later can be performed after cutting from the strip glass film 2.

[0092] When the first and second cuts are performed, the cutting process is completed, and the preparation process is completed accordingly. It should be noted that in this embodiment, the overflow pull-down method is used to obtain the chemically strengthened glass plate, but the slit pull-down method, float glass method, re-pulling method, etc., can also be used to obtain the chemically strengthened glass plate.

[0093] Here, it is preferable to perform chamfering on the end faces of the cut chemically strengthened glass sheet using processes such as grinding, heat treatment, and etching to improve its strength. On the other hand, after forming, the front and back surfaces of the chemically strengthened glass sheet are not subjected to grinding treatments (e.g., thinning treatments or chemical grinding treatments to reduce thickness). As a result, the front and back surfaces of the chemically strengthened glass sheet become the forged surfaces.

[0094] When the preparation process described above is completed, preparation Figure 3 as well as Figure 4 The chemically strengthened glass plate 12 shown (hereinafter referred to as glass plate 12). Figure 3 The glass plate 12 shown is Figure 4 The glass plate 12 shown is the same glass plate. Figure 3 This illustrates a first placement method in which the glass plate 12 is placed on a horizontal surface with one of its main surfaces 12a (front or back) facing upwards. On the other hand, Figure 4 This illustration shows a second placement method in which the glass plate 12 is placed on a horizontal surface with the other main surface 12b, located on the back side of one main surface 12a, facing upwards. It should be noted that in this embodiment, the horizontal surface refers to the horizontal support surface of the platform (not shown in the illustration).

[0095] It should be noted that, in this embodiment, the following situation is illustrated: one main surface 12a is a surface on the front or back of the glass plate 12 suitable for film-forming processes and is a guaranteed surface whose surface properties should be guaranteed, while the other main surface 12b is a non-guaranteed surface whose surface properties are not required to be the same as those of the first main surface 12a. As a method for determining guaranteed and non-guaranteed surfaces, for example, the main surface 12a on the front or back of the glass plate 12 that has been in contact with the transport roller or the like less frequently up to the completion of the aforementioned preparation process becomes a guaranteed surface, while the other main surface 12b on the side that has been in contact more frequently becomes a non-guaranteed surface. In this case, when comparing the one main surface 12a and the other main surface 12b, the guaranteed main surface 12a has fewer defects such as damage and contamination.

[0096] The type of glass plate 12 is not limited, but the glass plate 12 in this embodiment is aluminosilicate glass. As an example of glass composition, the glass plate 12 contains 50-80% SiO2, 5-25% Al2O3, 0-15% B2O3, 1-20% Na2O, and 0-10% K2O by mass%.

[0097] More preferably, the glass composition of the glass plate 12 in this embodiment contains, by mass%, 60-80% SiO2, 8-18% Al2O3, 0-5% B2O3, 0.01-10% Li2O, 4-16% Na2O, and 0.01-10% K2O.

[0098] It should be noted that increasing the Al2O3 content significantly improves the ion exchange performance of chemically strengthened glass, but excessively high Al2O3 content worsens devitrification. In other words, excessively high liquidus temperatures or excessively low liquidus viscosity preclude the use of overflow-based downdraw forming methods.

[0099] Na₂O is an ion-exchange component and has the effect of reducing the high-temperature viscosity of glass, thereby improving its meltability and formability, reducing the crack initiation rate, or lowering the strain point. It also improves devitrification. However, when the Na₂O content increases, the coefficient of thermal expansion becomes too large, reducing the glass's thermal shock resistance or making it difficult to match the coefficient of thermal expansion with surrounding materials. Furthermore, excessive Na₂O tends to worsen devitrification.

[0100] B₂O₃ has the effect of lowering the liquidus temperature, high-temperature viscosity, and density of glass. However, when the B₂O₃ content is high, burn marks may occur on the surface due to ion exchange. In addition, there is a possibility that the strain point may be lowered too much, and stress relief may easily progress during ion exchange, which may prevent the desired compressive stress from being achieved.

[0101] The type of glass plate 12 in this embodiment is not limited to chemically strengthened glass, and can also be applied to other ultra-thin glass plates such as low-alkali glass substrates. In ultra-thin glass plates, regardless of the material, the problem of breakage due to warping can still occur during processing steps such as cutting, cleaning, bundling, and chemical strengthening, so shape management is important.

[0102] In this embodiment, the glass plate 12 is expected to have a temperature of 70–100 × 10⁻⁶ at 30–380°C. -7 The coefficient of thermal expansion is approximately 1000 °C. While methods to reduce the coefficient of thermal expansion to suppress warping during chemical strengthening after molding are desirable, problems such as glass substrate peeling may occur if the coefficient of thermal expansion is not compatible with the surrounding materials. For example, in the case of foldable cover glass, there are organic materials such as metals and adhesives present in the surrounding area. Therefore, if the coefficient of thermal expansion of these materials is not compatible with theirs, the glass substrate may peel off when using adhesives made from organic materials for bonding. In this invention, with the aim of easily matching the coefficient of thermal expansion of the surrounding materials, the content of alkali metal oxides or alkaline earth metal oxides can be increased or the content of SiO2 and Al2O3 can be decreased to improve the coefficient of thermal expansion of the glass. Conversely, the content of alkali metal oxides or alkaline earth metal oxides can be decreased or the content of SiO2 and Al2O3 can be increased to decrease the coefficient of thermal expansion.

[0103] In this embodiment, the glass plate 12 is preferably 75 to 92 × 10⁻⁶ at a temperature of 30 to 380°C. -7 The coefficient of thermal expansion is / ℃. When the thermal expansion ratio is small, the thermal deformation in the high-temperature process of strengthening chemically strengthened glass plates is small, thus suppressing the increase in local warping after strengthening caused by contact with the fixtures that hold the glass in the chemical strengthening process, and the partial residue of strengthening liquids such as high-temperature potassium nitrate.

[0104] The shape of the glass plate 12 is not particularly limited, but it is rectangular in this embodiment. An example of the size of the glass plate 12 is 150mm × 150mm to 1100mm × 1300mm. The glass plate 12 of this embodiment has a long side 12x and a short side 12y, with the long side 12x having a length of 400mm or 500mm and the short side 12y having a length of 300mm or 400mm. It should be noted that in this glass plate 12, the extending direction of the long side 12x is consistent with the pulling direction (the length direction of the glass strip 5) in the forming process P1 to the cooling process P3 described above. Furthermore, even when the glass plate 12 is obtained by temporarily winding the strip glass film 2 after removing the non-effective portion 5b and then cutting the strip glass film 2 unwound from the roll, as described above, the extending direction of the long side 12x of the glass plate 12 is also consistent with the pulling direction.

[0105] It should be noted that when the width of the formed glass strip 5 (strip glass film 2) is sufficiently large, the glass plate 12 can also be extracted from the strip glass film 2 in such a way that the extension direction of the short side 12y of the glass plate 12 is consistent with the direction of the pulling plate.

[0106] The thickness of the glass plate 12 is 0.1 mm or less, preferably 0.01 mm or more and 0.095 mm or less, more preferably 0.02 mm or more and 0.085 mm or less, and even more preferably 0.025 mm or more and 0.075 mm or less. For further thinning, the thickness of the glass plate 12 can also be 0.065 mm or less, 0.055 mm or less, or 0.05 mm or less. On the other hand, the lower limit of the thickness of the glass plate 12 is 0.025 mm or more, more preferably 0.03 mm or more. When the glass plate 12 is made too thin, the deflection of the glass plate 12 becomes too large, making it difficult to ensure strength. Furthermore, when the glass plate 12 is excessively thinned, the difference between the thickness of the glass accumulation portion at the ends of the glass plate 12 during forming and the thickness of the central portion of the glass plate 12 in the finished product becomes large, further making it difficult to achieve a good thickness distribution of the formed glass plate 12 and suppress warping.

[0107] In particular, when the glass plate 12 becomes thinner, the thickness difference between the non-effective portions 5b at both ends of the strip glass film 2 in the width direction and the effective portion 5a in the center of the width direction becomes more significant. Therefore, warping is easily caused near the periphery of the glass plate 12, especially near the corners. Furthermore, warping removal becomes difficult and the effective portion decreases, resulting in warping shape deterioration during chemical strengthening processes at high temperatures such as 360°C and above, and breakage during the processing steps, significantly reducing the efficiency of product extraction as chemically strengthened glass. In addition, maintaining the glass shape when the glass plate 12 for chemical strengthening is supplied to the chemical strengthening process becomes very difficult, causing a further increase in glass deformation.

[0108] In this embodiment, the glass plate 12 has a substantially uniform thickness throughout. "Substantially uniform thickness" means that the thickness deviation of the glass plate 12 is ±20% or less. It should be noted that the thickness deviation of the glass plate 12 is preferably ±10% or less, and more preferably ±5% or less.

[0109] The glass plate 12 has warping, which causes unevenness to form on one main surface 12a and the other main surface 12b. Therefore, in either the first or second mounting method, there is a portion of the glass plate 12 that floats above the aforementioned horizontal plane. Here, in the first and second mounting methods, respectively... Figure 3 as well as Figure 4 The XY coordinates are shown. That is, one of the four corners of the glass plate 12 is taken as the origin S, the X-axis [mm] is taken along the direction of the long side 12x, and the Y-axis [mm] is taken along the direction of the short side 12y. Therefore, if we consider the lengths of the long side 12x and the short side 12y (400mm×300mm or 500mm×400mm) already described in this embodiment, the coordinates of points A, B, and C shown in the two figures are (400, 0), B is (400, 300), and C is (0, 300) or A is (500, 0), B is (500, 400), and C is (0, 400).

[0110] Furthermore, the glass plate 12 is configured as described in (1) to (8) below.

[0111] (1) Set the thickness of glass plate 12 to t [mm].

[0112] (2) When adopting the first placement method ( Figure 3 In the case of ), the position of the glass plate 12 at its highest height above the horizontal plane is set as the first peak position D1.

[0113] (3) Set the height of the glass plate 12 at the first peak position D1 above the horizontal plane as W. 1MAX [mm].

[0114] (4) When adopting the second placement method ( Figure 4 In the case of ), the position of the glass plate 12 at its highest height above the horizontal plane is set as the second peak position D2.

[0115] (5) Set the height of the glass plate 12 at the second peak position D2 above the horizontal plane as W. 2MAX [mm].

[0116] (6) The portion of the glass plate 12 with a width of 10mm along its periphery (edge) (having Figure 3 as well as Figure 4 The area with the crosshairs shown (width L1) is designated as the periphery 12e.

[0117] (7) When adopting the first placement method ( Figure 3 In the case of ), the height of the position D3 (hereinafter referred to as the first peripheral peak position D3) with the highest height above the horizontal plane within the perimeter 12e is set as W. 1OUT [mm].

[0118] (8) When adopting the second placement method ( Figure 4 In the case of ), the height of the position D4 (hereinafter referred to as the second peripheral peak position D4) with the highest height above the horizontal plane within the perimeter 12e is set as W. 2OUT [mm].

[0119] In this embodiment, an Apollo Precision 1313SK glass substrate warpage measuring machine is used as the measuring device. The height of each position on the upper surface of the glass plate 12, with the first peak position D1 and the second peak position D2 as the starting points, is measured when the glass plate 12 is horizontally placed. It should be noted that... Figure 3 as well as Figure 4 The positions of the first peak (D1), the second peak (D2), the first peripheral peak (D3), and the second peripheral peak (D4) shown are merely examples of these positions.

[0120] Here, the multiple height measurement positions, determined by the aforementioned measuring device, are distributed along the XY coordinates. In other words, the height is not measured at all positions on the glass plate 12. Therefore, the first peak position D1 and the second peak position D2 only refer to the positions with the highest height among those measured. That is, there is a high probability that there is a positional deviation between the truly highest position (the most upward-protruding position among all positions on the glass plate 12) and the first peak position D1 and the second peak position D2. Consequently, the height at the truly highest position is different from the aforementioned W. 1MAX value, W 2MAX The values ​​are highly likely to deviate from each other. Therefore, it is necessary to narrow the interval between adjacent measurement positions to a level that allows the deviation to be ignored. Preferably, the interval between adjacent measurement positions is 100 mm or less in both the X-axis and Y-axis directions, more preferably 50 mm or less, even more preferably 30 mm or less, further preferably 20 mm or less, and most preferably 10 mm or less and 5 mm or less. However, from the viewpoint of shortening the measurement time, the interval between adjacent measurement positions can be expanded as much as possible within the range of obtaining the required accuracy.

[0121] Under the provisions of (1) to (8) above, such as Figure 3As shown, the first peak position D1 in this glass plate 12 exists in a portion of the glass plate 12 that is closer to the center than the peripheral portion 12e when viewed from above. That is, when the coordinates of the first peak position D1 are set to D1(X1, Y1), when the long side 12x is 400mm and the short side 12y is 300mm, 10 < X1 < 390 and 10 < Y1 < 290 are satisfied. Furthermore, when the long side 12x is 500mm and the short side 12y is 400mm, 10 < X1 < 490 and 10 < Y1 < 390 are satisfied. It should be noted that, preferably, the first peak position D1 is located in a portion of the glass plate 12 with a width of 50mm along the periphery (having... Figure 3 as well as Figure 4 When the area with the applied shadow line (the width L2 shown) is designated as the second peripheral portion 12f, the first peak position D1 exists in the glass plate 12 at a location closer to the inner side than the second peripheral portion 12f. That is, when the long side 12x is 400mm and the short side 12y is 300mm, it is suitable to satisfy 50 < X1 < 350 and 50 < Y1 < 250. Furthermore, when the long side 12x is 500mm and the short side 12y is 400mm, it is suitable to satisfy 50 < X1 < 450 and 50 < Y1 < 350. In this way, since the highest warped top exists further inside the glass plate, it is less likely to cause damage near the cutting start point (end face) or cutting errors caused by abnormal laser focus when the glass plate is cut into single small substrates using diamond scribing, bending stress, or laser cutting in subsequent processes for use in smaller, such as foldable, devices.

[0122] Furthermore, in this glass plate 12, it is preferable to satisfy t 2 / W 1OUT >0.005, W 1OUT ≤0.20mm (preferably W) 1OUT ≤0.10mm), W 1OUT / t<5、W 1MAX Relationships such as / t<15.

[0123] Moreover, in this glass plate 12, such as Figure 4As shown, the second peak position D2 exists in the glass plate 12 at a location inside the periphery 12e. That is, when the coordinates of the second peak position D2 are set to D2(X2, Y2), then when the long side 12x is 400mm and the short side 12y is 300mm, 10 < X2 < 390 and 10 < Y2 < 290 are satisfied. Furthermore, when the long side 12x is 500mm and the short side 12y is 400mm, 10 < X2 < 490 and 10 < Y2 < 390 are satisfied. It should be noted that, preferably, the second peak position D2 exists in the glass plate 12 at a location inside the second periphery 12f. That is, when the long side 12x is 400mm and the short side 12y is 300mm, it is suitable to satisfy 50 < X2 < 350 and 50 < Y2 < 250. In addition, when the long side 12x is 500mm and the short side 12y is 400mm, it is appropriate to satisfy 50 < X2 < 450 and 50 < Y2 < 350.

[0124] Furthermore, in this glass plate 12, it is preferable to satisfy t 2 / W 2OUT >0.005, W 2OUT ≤0.20mm (preferably W) 2OUT ≤0.10mm), W 2OUT / t<5、W 2MAX Relationships such as / t<15.

[0125] According to this glass plate 12, during the manufacturing process that the glass plate 12 undergoes before becoming a tempered glass plate, damage caused by warping can be avoided as much as possible.

[0126] [Cutting process]

[0127] A cutting process is performed on the glass plate 12 prepared in the preparation process. Since the cutting process can be performed using known methods, a detailed description is omitted. When the cutting process is completed, a product-size glass plate (e.g., a glass plate suitable for the screen size of a smartphone or tablet PC) is obtained. It should be noted that there are cases where one product-size glass plate is cut from one glass plate 12, and there are also cases where multiple product-size glass plates are cut from one glass plate 12.

[0128] [Enhanced Process]

[0129] In the strengthening process, a strengthened glass sheet is obtained by chemically strengthening the glass sheet of the product size obtained from the cutting process, thereby forming a compressive stress layer (a layer subjected to compressive stress) on both the surface and back sides. The specific method of chemical strengthening is well known, so detailed descriptions are omitted. Through the above, the strengthening process is completed, and a strengthened glass sheet is manufactured.

[0130] Example 1

[0131] As a first embodiment, chemically strengthened glass plates (Examples 1-18, Comparative Examples 1-4) with the parameters shown in Tables 1-4 were prepared respectively, and the proportion of glass plates that broke due to warping during the manufacturing process before becoming strengthened glass plates (breakage rate) was calculated. Specifically, the manufacturing process included a cutting process to cut the chemically strengthened glass plate from the original glass film, a cleaning process after cutting, and an appearance inspection process. It should be noted that the chemically strengthened glass plates in the examples were glass plates containing, by molar percentage, 61.6% SiO2, 18.0% Al2O3, 0.5% B2O3, 3.0% MgO, 14.5% Na2O, 2.0% K2O, and 0.4% SnO2, with a strain point of 564°C, and having a 91×10⁻⁶ particle size distribution at 30-380°C. -7 The glass plate has a coefficient of thermal expansion of / ℃ and is formed by overflow pull-down method. Furthermore, in the embodiments, the thermal history during annealing and the cutting position from the original glass film plate are adjusted respectively.

[0132] All parameters shown in Tables 1 to 4 are the same as those described in the embodiments above. Furthermore, in Tables 1 to 4, "first surface" indicates the case where the glass plate is placed on a horizontal surface with the guaranteed surface (one main surface) facing upwards (the case of the first placement method). On the other hand, "second surface" indicates the case where the glass plate is placed on a horizontal surface with the non-guaranteed surface (the other main surface) facing upwards (the case of the second placement method). Moreover, in the item "maximum value is inside," "○" means that the first peak position (second peak position) exists in a portion of the glass plate that is inside the periphery, and "×" means that the first peak position (second peak position) exists within the periphery of the glass plate. Here, the height of the glass plate (long side × short side: 400mm × 300mm) from the horizontal surface is measured on the XY coordinate system at each coordinate point where a line parallel to the Y-axis and a line parallel to the X-axis, each set with a 5mm scale, intersect. In this first embodiment, the case where the width of the periphery of the glass plate is set to 10 mm was examined. Therefore, if at least one of the following conditions is met: the X-coordinate of the first peak position is 10 mm or less or 390 mm or more, and the Y-coordinate of the first peak position is 10 mm or less or 290 mm or more, the item regarding the "maximum value is inside" for the first peak position is marked "×"; if neither condition is met, the item regarding the "maximum value is inside" for the first peak position is marked "○". Similarly, if at least one of the following conditions is met: the X-coordinate of the second peak position is 10 mm or less or 390 mm or more, and the Y-coordinate of the second peak position is 10 mm or less or 290 mm or more, the item regarding the "maximum value is inside" for the second peak position is marked "×"; if neither condition is met, the item regarding the "maximum value is inside" for the second peak position is marked "○".

[0133] The specific method for calculating the breakage rate will be explained using Example 1 as an example. First, multiple chemically strengthened glass plates were prepared and manufactured under the same conditions as the glass plate in Example 1. Furthermore, for each glass plate, the presence or absence of breakage was determined through an appearance inspection process at the moment the cleaning process in the aforementioned manufacturing process was completed. The breakage rate was calculated by determining the proportion of broken glass plates among the multiple glass plates. The breakage rate was also calculated using the same method for Examples 2-18 and Comparative Examples 1-4. It should be noted that the number of chemically strengthened glass plates manufactured under the same conditions as in each example and comparative example was set to 200-500 (the number varied depending on the example and comparative example).

[0134] [Table 1]

[0135]

[0136] According to the breakage rates shown in [Table 1], in Examples 1-5, where the first peak is located on the inner side of the glass plate compared to the periphery, no breakage of the glass plate occurred. Here, Figure 5 This illustrates the warping distribution (ensuring the unevenness of the surface) when Y=105, including the first peak position, is adopted in the first mounting method of Embodiment 5. It should be noted that... Figure 5 The heights measured at X = 5, 55, 105, 155, 205, 255, 305, 355, and 395 are shown in the figure.

[0137] [Table 2]

[0138]

[0139] According to the breakage rates shown in [Table 2], in Examples 6 and 7 of Examples 6 to 9, where the first peak is located in the portion of the glass plate closer to the periphery than the outer edge, no breakage of the glass plate occurred. Furthermore, it can be seen that even in Examples 8 and 9, where breakage did occur, the breakage rate of the glass plate was significantly suppressed compared to Comparative Examples 1 and 2, where the first peak was located within the periphery of the glass plate.

[0140] [Table 3]

[0141]

[0142] According to the breakage rates shown in Table 3, in Examples 10-13, where the first peak is located on the inner side of the glass plate compared to the periphery, no breakage of the glass plate occurred. In contrast, in Comparative Example 3, where the first peak is located within the periphery of the glass plate, breakage of the glass plate occurred despite having the same plate thickness as in Examples 10-13.

[0143] [Table 4]

[0144]

[0145] According to the breakage rate shown in Table 4, it is difficult to completely suppress breakage during the process when the plate thickness is very thin, such as 0.03 mm. However, in Examples 14 to 18, where the first peak position is located in the part of the glass plate that is closer to the periphery than in Comparative Example 4, the breakage rate of the glass plate is significantly suppressed compared to that in Comparative Example 4, where the first peak position is located in the periphery of the glass plate.

[0146] Here, in embodiments 14 and 15, in addition to satisfying the condition that the first peak is located in a portion of the glass plate that is more inward than the periphery, the following relationships are also satisfied, namely W 1OUT≤0.20mm, t 2 / W 1OUT >0.005, W 1OUT / t<5、W 1MAX / t<15、W 2OUT ≤0.20mm, t 2 / W 2OUT >0.005, W 2OUT / t<5、W 2MAX All of the relations such as / t<15. On the other hand, in Example 16, only W in the relations listed above is not satisfied. 1OUT The relationship / t < 5. In Example 17, W is not satisfied. 2OUT ≤0.20mm, t 2 / W 2OUT >0.005, W 2OUT The three relationships / t<5 are not satisfied. In Example 18, W is not satisfied. 2OUT ≤0.20mm, t 2 / W 2OUT >0.005, W 2OUT / t<5、W 2MAX The four relationships are: / t < 15. It should be noted that in Example 18, the second peak is located within the periphery of the glass plate. Based on this, it can be seen that in glass plates with a thickness reduced to 0.03 mm, there is a tendency for lower breakage rates when more of the relationships listed above are satisfied.

[0147] Table 5 below shows the height [μm] of the glass plate above the horizontal plane measured at the coordinates shown in the table when the first mounting method was used in Example 14. Additionally, Figure 6 This shows the distribution of warping in this case (ensuring the distribution of surface unevenness). It should be noted that Tables 5 and later, Tables 6 through 16, and... Figure 6 and the references thereafter Figures 8 to 18 The heights measured at a portion of the coordinates are shown. Specifically, the heights measured at the intersections of nine lines parallel to the Y-axis (represented by X = 5, 55, 105, 155, 205, 255, 305, 355, 395) and seven lines parallel to the X-axis (represented by Y = 5, 55, 105, 155, 205, 255, 295) are shown. Furthermore, Figure 7 The diagram shows the warping distribution at Y=55, including the location of the first peak (ensuring the distribution of surface unevenness). Regarding... Figure 7The heights measured at X = 5, 55, 105, 155, 205, 255, 305, 355, and 395 are also shown. In this case, the average height is 45 μm (0.045 mm). Furthermore, the standard deviation of the height is 0.050.

[0148] [Table 5]

[0149]

[0150] Table 6 below shows the height [μm] of the glass plate above the horizontal plane measured at the coordinates shown in the table when the second mounting method was used in Example 14. Additionally, Figure 8 The distribution of warpage in this case (the distribution of unevenness on the non-guaranteed surface) is shown. In this case, the average height is 69 μm (0.069 mm). Furthermore, the standard deviation of the height is 0.058.

[0151] [Table 6]

[0152]

[0153] Table 7 below shows the height [μm] of the glass plate above the horizontal plane measured at the coordinates shown in the table when the first mounting method was used in Example 15. Additionally, Figure 9 The distribution of warpage (the distribution of surface irregularities) is shown in this case. In this case, the average height is 63 μm (0.063 mm). Furthermore, the standard deviation of the height is 0.055.

[0154] [Table 7]

[0155]

[0156] Table 8 below shows the height [μm] of the glass plate above the horizontal plane measured at the coordinates shown in the table when the second mounting method was used in Example 15. Additionally, Figure 10 The distribution of warpage in this case (the distribution of unevenness on the non-guaranteed surface) is shown. In this case, the average height is 64 μm (0.064 mm). Furthermore, the standard deviation of the height is 0.083.

[0157] [Table 8]

[0158]

[0159] Table 9 below shows the height [μm] of the glass plate above the horizontal plane measured at the coordinates shown in the table when the first mounting method was used in Example 16. Additionally, Figure 11The distribution of warpage (the distribution of surface irregularities) is shown in this case. In this case, the average height is 46 μm (0.046 mm). Furthermore, the standard deviation of the height is 0.048.

[0160] [Table 9]

[0161]

[0162] Table 10 below shows the height [μm] of the glass plate above the horizontal plane measured at the coordinates shown in the table when the second mounting method was used in Example 16. Additionally, Figure 12 The distribution of warpage in this case (the distribution of unevenness on the non-guaranteed surface) is shown. In this case, the average height is 48 μm (0.048 mm). Furthermore, the standard deviation of the height is 0.037.

[0163] [Table 10]

[0164]

[0165] Table 11 below shows the height [μm] of the glass plate above the horizontal plane measured at the coordinates shown in the table when the first mounting method was used in Example 17. Additionally, Figure 13 The distribution of warpage (the distribution of surface irregularities) is shown in this case. In this case, the average height is 84 μm (0.084 mm). Furthermore, the standard deviation of the height is 0.076.

[0166] [Table 11]

[0167]

[0168] Table 12 below shows the height [μm] of the glass plate above the horizontal plane measured at the coordinates shown in the table when the second mounting method was used in Example 17. Additionally, Figure 14 The distribution of warpage in this case (the distribution of unevenness on the non-guaranteed surface) is shown. In this case, the average height is 90 μm (0.09 mm). Furthermore, the standard deviation of the height is 0.098.

[0169] [Table 12]

[0170]

[0171] Table 13 below shows the height [μm] of the glass plate above the horizontal plane measured at the coordinates shown in the table when the first mounting method was used in Example 18. Additionally, Figure 15The distribution of warpage (the distribution of surface irregularities) is shown in this case. In this case, the average height is 70 μm (0.07 mm). Furthermore, the standard deviation of the height is 0.078.

[0172] [Table 13]

[0173]

[0174] Table 14 below shows the height [μm] of the glass plate above the horizontal plane measured at the coordinates shown in the table when the second mounting method was used in Example 18. Additionally, Figure 16 This illustrates the warping distribution in this case (the distribution of unevenness on the non-guaranteed surface). As shown in the figure, in this case, the second peak position D2 coincides with the second peripheral peak position D4 (W 2MAX The value of W 2OUT (The values ​​are the same). In this case, the average height is 72 μm (0.072 mm). Additionally, the standard deviation of the height is 0.094.

[0175] [Table 14]

[0176]

[0177] Table 15 below shows the height [μm] of the glass plate above the horizontal plane measured at the coordinates shown in the table when the first mounting method was used in Comparative Example 4. Additionally, Figure 17 This illustrates the warping distribution in this case (ensuring the distribution of surface irregularities). As shown in the figure, in this case, the first peak position D1 coincides with the first peripheral peak position D3 (W 1MAX The value of W 1OUT (The values ​​are the same). In this case, the average height is 101 μm (0.101 mm). Additionally, the standard deviation of the height is 0.128.

[0178] [Table 15]

[0179]

[0180] Table 16 below shows the height [μm] of the glass plate above the horizontal plane measured at the coordinates shown in the table when the second mounting method was used in Comparative Example 4. Additionally, Figure 18 This illustrates the warping distribution in this case (the distribution of unevenness on the non-guaranteed surface). As shown in the figure, in this case, the second peak position D2 coincides with the second peripheral peak position D4 (W 2MAX The value of W 2OUT (The values ​​are the same). In this case, the average height is 73 μm (0.073 mm). Additionally, the standard deviation of the height is 0.077.

[0181] [Table 16]

[0182]

[0183] As shown above, it can be seen that in Examples 17 and 18, where the average height and standard deviation of height are relatively large in Examples 14-18, breakage of the glass plate can also be suppressed (see also Table 4 above). That is, even glass plates with a portion that is higher than the horizontal plane due to warping, and glass plates with large variations in the unevenness of the guaranteed and non-guaranteed surfaces due to warping, breakage can be suppressed. This result is presumably because in each embodiment the first peak position exists in a portion of the glass plate that is closer to the periphery.

[0184] Next, as a second embodiment, another chemically strengthened glass plate (Example 19) having the parameters shown in [Table 17] below was prepared, and the proportion (breakage rate) of glass plates that broke due to warping during the manufacturing process before becoming strengthened glass plates was calculated. Specifically, the manufacturing process included a cutting process to cut the chemically strengthened glass plate from the original glass film, a cleaning process after cutting, and an appearance inspection process. It should be noted that the chemically strengthened glass plate in the second embodiment is a glass plate containing, by molar percentage, 66.1% SiO2, 14.0% Al2O3, 2.5% B2O3, 3.0% MgO, 13.4% Na2O, and 0.6% K2O, with a strain point of 551°C and a strength of 79 × 10⁻⁶ at 30–380°C. -7 The glass plate has a coefficient of thermal expansion of / ℃ and is formed by overflow pull-down method.

[0185] The height of the glass plate (long side × short side: 500mm × 400mm) above the horizontal plane in the second embodiment was measured at each coordinate point on the XY coordinate system, where a straight line parallel to the Y-axis and a straight line parallel to the X-axis, each set with a 5mm scale, intersect. In this second embodiment, the case where the width of the perimeter of the glass plate was set to 50mm was examined. Therefore, if at least one of the following conditions is met: the X-coordinate of the first peak position is 50mm or less or 450mm or more, and the Y-coordinate of the first peak position is 50mm or less or 350mm or more, the item "maximum value is inside" regarding the first peak position is "×"; if neither condition is met, the item "maximum value is inside" regarding the first peak position is "○". Similarly, if at least one of the following conditions is met, such as the X-coordinate of the second peak position being 50 mm or less or 450 mm or more, and the Y-coordinate of the second peak position being 50 mm or less or 350 mm or more, the item "maximum value is inside" regarding the second peak position becomes "×", and if no condition is met, the item "maximum value is inside" regarding the second peak position becomes "○".

[0186] [Table 17]

[0187]

[0188] According to the breakage rate shown in Table 17, in Example 19, where the first peak is located on the inner side of the glass plate from the periphery (width 50 mm), no breakage of the glass plate occurred.

[0189] Table 18 below shows the height [μm] of the glass plate above the horizontal plane measured at the coordinates shown in the table when the first mounting method is used in Example 19. Additionally, Figure 19 The distribution of warping (the distribution of surface unevenness) in this case is shown. Specifically, the heights measured at the coordinates where 11 lines parallel to the Y-axis (denoted by X = 15, 65, 115, 165, 215, 265, 315, 365, 415, 465, 485) and 9 lines parallel to the X-axis (denoted by Y = 15, 65, 115, 165, 215, 265, 315, 365, 385) intersect are shown. In this case, the average height is 51 μm (0.051 mm). Furthermore, the standard deviation of the height is 0.062.

[0190] [Table 18]

[0191]

[0192] Table 19 below shows the height [μm] of the glass plate above the horizontal plane measured at the coordinates shown in the table when the second mounting method is used in Example 19. Additionally, Figure 20 The distribution of warpage (the unevenness distribution of the non-guaranteed surface) is shown in this case. In this case, the average height is 67 μm (0.067 mm). Furthermore, the standard deviation of the height is 0.077.

[0193] [Table 19]

[0194]

[0195] Explanation of reference numerals in the attached figures

[0196] D1: First peak position, D2: Second peak position, D3: First peripheral peak position, D4: Second peripheral peak position, 12: Glass plate for chemical strengthening, 12a: One main surface, 12b: The other main surface, 12e: Peripheral portion.

Claims

1. A chemically strengthened glass plate, wherein the thickness of the chemically strengthened glass plate is less than 0.1 mm. The chemically strengthened glass plate is characterized in that... The chemically strengthened glass plate has an overall warped shape or has locally warped parts. Let the thickness of the glass plate be t [mm]. When the glass plate is placed on a horizontal surface with one of its main surfaces facing upwards, the position where the glass plate is at its highest point above the horizontal surface is designated as the first peak position. The portion of the glass plate with a width of 10mm along its perimeter is defined as the perimeter. In this case, The first peak is located in a portion of the glass plate that is more inward than the periphery.

2. The chemically strengthened glass plate according to claim 1, characterized in that, When the first mounting method is adopted, the height of the position with the highest height from the horizontal plane within the periphery is set as W. 1OUT When [mm], Satisfy t 2 / W 1OUT A relationship greater than 0.

005.

3. The chemically strengthened glass plate according to claim 1 or 2, characterized in that, When the first mounting method is adopted, the height of the position with the highest height from the horizontal plane within the periphery is set as W. 1OUT [mm], Satisfy W 1OUT The relationship is ≤0.20mm.

4. The chemically strengthened glass plate according to claim 1 or 2, characterized in that, When the first mounting method is adopted, the height of the position with the highest height from the horizontal plane within the periphery is set as W. 1OUT [mm], Satisfy W 1OUT The relationship between / t<5.

5. The chemically strengthened glass plate according to claim 1 or 2, characterized in that, Let W be the height of the glass plate at the first peak position from the horizontal plane. 1MAX In the case of [mm], Satisfy W 1MAX The relationship between / t<15.

6. The chemically strengthened glass plate according to claim 1 or 2, characterized in that, The one main surface and the other main surface located on the back side of the one main surface are forged surfaces.

7. The chemically strengthened glass plate according to claim 1 or 2, characterized in that, The thickness of the glass plate is less than 0.05 mm.

8. The chemically strengthened glass plate according to claim 1 or 2, characterized in that, The thickness deviation of the glass plate as a whole is less than ±20%.

9. The chemically strengthened glass plate according to claim 1, characterized in that, In the second placement method where the glass plate is placed on the horizontal plane with the other main surface located on the back side of the said main surface facing upwards, and the position of the glass plate at its highest point above the horizontal plane is designated as the second peak position, The second peak is located in a portion of the glass plate that is more inward than the periphery.

10. The chemically strengthened glass plate according to claim 9, characterized in that, When the second mounting method is adopted, the height of the position with the highest height from the horizontal plane within the periphery is set as W. 2OUT When [mm], Satisfy t 2 / W 2OUT A relationship greater than 0.

005.

11. The chemically strengthened glass plate according to claim 9 or 10, characterized in that, When the second mounting method is adopted, the height of the position with the highest height from the horizontal plane within the periphery is set as W. 2OUT When [mm], Satisfy W 2OUT The relationship is ≤0.20mm.

12. The chemically strengthened glass plate according to claim 9 or 10, characterized in that, When the second mounting method is adopted, the height of the position with the highest height from the horizontal plane within the periphery is set as W. 2OUT When [mm], Satisfy W 2OUT The relationship between / t<5.

13. The chemically strengthened glass plate according to claim 9 or 10, characterized in that, Let W be the height of the glass plate at the second peak position from the horizontal plane. 2MAX When [mm], Satisfy W 2MAX The relationship between / t<15.

14. The chemically strengthened glass plate according to any one of claims 1, 2, 9, and 10, characterized in that, The glass plate is made of aluminosilicate glass. As a glass composition, it contains, by mass%, 50–80% SiO2, 5–25% Al2O3, 0–15% B2O3, 1–20% Na2O, and 0–10% K2O.

15. The chemically strengthened glass plate according to claim 14, characterized in that, The glass plate is aluminosilicate glass, and as a glass composition, it contains 60-80% SiO2, 8-20% Al2O3, 0-5% B2O3, 4-16% Na2O, and 0.01-10% K2O by mass%.

16. The chemically strengthened glass plate according to any one of claims 1, 2, 9, and 10, characterized in that, The glass plate is rectangular. The glass plate has a length of 150mm to 1100mm and a width of 150mm to 1300mm.

17. A method for manufacturing a reinforced glass plate, characterized in that, The method for manufacturing the reinforced glass sheet includes a preparation step of preparing a glass sheet for chemical strengthening according to any one of claims 1 to 16, a cutting step of cutting a glass sheet of product size from the glass sheet, and a strengthening step of obtaining a reinforced glass sheet by chemically strengthening the glass sheet of product size.

18. A glass plate having a thickness of 0.1 mm or less. The glass plate is characterized in that... The glass plate has an overall warped shape or has locally warped parts. When the glass plate is placed on a horizontal surface with one of its main surfaces facing upwards, the position where the glass plate is at its highest point above the horizontal surface is designated as the first peak position. The portion of the glass plate with a width of 10mm along its perimeter is defined as the perimeter. In this case, The first peak is located in a portion of the glass plate that is more inward than the periphery.

19. The glass plate according to claim 18, characterized in that, In the second placement method where the glass plate is placed on the horizontal plane with the other main surface located on the back side of the said main surface facing upwards, and the position of the glass plate at its highest point above the horizontal plane is designated as the second peak position, The second peak is located in a portion of the glass plate that is more inward than the periphery.

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