JP2019194142A - Chemically reinforced glass sheet, portable information terminal, and manufacturing method of chemically reinforced glass sheet - Google Patents

Abstract

To provide a chemically reinforced glass sheet of which whole is chemically reinforced and strength is improved, and a manufacturing method therefor.SOLUTION: There is provided a glass sheet 1 having a first surface 2, a second surface 3 facing the first surface 2, a first region 10 having prescribed thickness in a normal direction of the first surface 2, and a second region 20 containing a thick region which is thicker than the first region 10, in which the first region 10 is a continuous thickness from thickness W, which is the thickness of the thickest part, to thickness 1.1×W, the second region 20 is a region having thickness of over 1.1×W, and has a part where depth of a compressive stress layer in the second region 20 is formed at more depth than thickness of the compressive stress layer of the first region 10, in which Wis the thickness of the thickest part in the region having thickness of the 1.1×W, depth of the compressive stress layer is 80 μm in the first region 10 and the second region 20, and Land Lsatisfy a relational expression of L/W≥1.2, in which Lis depth of the compressive stress layer at the thickness Wand Lis depth of the compressive stress layer at the thickness W.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a chemically strengthened glass plate, a portable information terminal, and a method for manufacturing a chemically strengthened glass plate.

  In recent years, as a cover member of a portable information terminal such as a mobile electronic device such as a smartphone, a technique using a chemically strengthened glass plate instead of a synthetic resin is known (Patent Documents 1 and 2). Moreover, the technique of chemically strengthening a glass plate is known.

  Patent Document 1 includes a central region and a curved region formed to be curved. On the back side, the thickness of the compressive stress layer formed in the curved region is the compressive stress formed in the central region. It is disclosed that it is a display cover glass that is thicker than the thickness of the layer, and maintains a predetermined strength with respect to the curved inner region of the curved portion.

  Patent Document 2 is similar to Patent Document 1, and the thickness of the curved region is larger than the thickness of the central region in the range of 0.5 mm to 2.5 mm, and the curved region is the curved region. It is disclosed that the approximate R of the region having the smallest approximate R (curvature radius) among the concave regions located inside the curve is formed so as to be 2.5 mm or more.

JP 2013-121897 A JP2013-125118A

  Patent Documents 1 and 2 disclose that when a glass plate is used for an electronic device such as a mobile phone, the thickness of the compressive stress layer is increased by paying attention to the fact that the curved portion of the glass plate is vulnerable to impact and easily cracked. Yes. However, even if the glass plate is chemically strengthened within the range disclosed in these patent documents, the entire glass plate is not fully chemically strengthened, and particularly the strength such as impact resistance at the end and end face is insufficient. There was a problem of being.

  Then, this invention aims at provision of the manufacturing method of the chemically strengthened glass plate, the portable information terminal, and the chemically strengthened glass plate by which the whole was chemically strengthened and the intensity | strength improved.

The chemically strengthened glass plate of the present invention has a thickness in a normal direction of a first surface, a second surface opposite to the first surface, and a tangent to the first surface, and is made of the predetermined thickness. a first region, a second region including a thicker region than the thickness of the first region, said first region, when the thickness W _a the thickness of the thinnest portion , _A continuous region from the thickness WA to a thickness of 1.1 × W _A , and the second region is a region having a thickness of more than 1.1 × W _A and the thickest portion of the thickness and W _B, the depth of the compressive stress layer in the second region has a portion that is deeper than the depth of the compression stress layer of the first region, said first region in the second region, the depth of the compressive stress layer is not less 80μm or more, the depth of the compressive stress layer position of the thickness W _a and L _a, the thickness W The depth of the compressive stress layer in position _B and _{L B, L A} and _{L B may} satisfy the relationship of _L B / L _A ≧ 1.2.

According to chemically strengthened glass plate of the present invention, the in the first region and the second region, the depth of the compressive stress layer is not less 80μm or more, the depth of the compressive stress layer in the first region L _A And the depth L _B of the compressive stress layer in the second region satisfies the relational expression of L _B / L _A ≧ 1.2, so that the strength of the entire glass plate is increased and more than in the first region. The depth of the compressive stress layer in the second region formed thicker becomes deeper. Thereby, for example, by increasing the strength of the second region including the end portion and the vicinity of the end surface, occurrence of cracks starting from the end portion and the end surface can be suppressed, and the convenience and safety in use can be improved.

1 (a) and 1 (b) show a chemically strengthened glass plate according to the present invention, FIG. 1 (a) is a sectional view of the first embodiment, and FIG. 1 (b) shows the relationship with a portable information terminal. It is a perspective view shown. 2 (a) to 2 (c) show a chemically strengthened glass plate according to the present invention, FIG. 2 (a) is a sectional view of the second embodiment, and FIG. 2 (b) is the first embodiment. Sectional drawing which shows the relationship with the portable information terminal based on FIG. 2, FIG.2 (c) is sectional drawing which shows the relationship with the portable information terminal based on 2nd Embodiment. FIGS. 3A to 3E show other chemically tempered glass sheets according to the present invention and are other cross-sectional views of the second embodiment. FIG. 4 is a sectional view of a third embodiment of the chemically strengthened glass sheet according to the present invention. FIGS. 5A and 5B are graphs showing the relationship between the depth of the compressive stress layer, the compressive stress, and the tensile stress in the cross section of the chemically strengthened glass plate. 6A to 6C show an example of a stress measuring device that measures the compressive stress and the depth of the compressive stress layer, FIG. 6A is a schematic diagram, and FIG. 6B is a block of an arithmetic means. FIG. 6 and FIG. 6C are flowcharts showing the measurement procedure. FIG. 7 is a graph showing the relationship between the depth of the compressive stress layer and the thickness of the glass. FIG. 8 is a graph showing the relationship between the compressive stress CS and the depth direction of the first region and the second region of the chemically strengthened glass sheet according to the present invention. FIGS. 9A to 9C are diagrams for explaining a method for producing a three-dimensionally shaped chemically strengthened glass plate according to the present invention. 10 (a) to 10 (c) are diagrams for explaining another manufacturing method of the chemically strengthened glass plate having a three-dimensional shape according to the present invention. 11 (a) and 11 (b) are diagrams for explaining another method for producing a three-dimensionally shaped chemically strengthened glass plate according to the present invention.

  Hereinafter, the details and other features of the present invention will be described based on embodiments for carrying out the invention. In the following drawings, the same or corresponding members or parts are denoted by the same or corresponding reference numerals, and redundant description is omitted. Also, the drawings are not intended to show relative ratios between members or parts unless otherwise specified. Thus, specific dimensions can be selected as appropriate in light of the following non-limiting embodiments.

  The chemically strengthened glass plate according to the embodiment of the present invention can be suitably used for a portable information terminal such as a portable electronic device. For example, a cover glass of a mobile phone, a smartphone, a tablet PC, or the like. In addition to these uses, there are uses that require high strength, such as magnetic disk substrates, flat panel display substrates, solar cell cover glasses, and the like, but are not limited to these examples.

  FIG. 1A is a cross-sectional view of the first embodiment of the glass plate 1. The glass plate 1 of the present embodiment has a first surface 2 and a second surface 3. The 1st surface 2 is a surface which a user's hand touches, when the glass plate 1 is used as cover glasses, such as a smart phone, and the 2nd surface 3 opposes the 1st surface 2, and is a back surface. The glass plate 1 has a thickness W extending from the first surface 2 to the second surface 3, has a substantially quadrangular shape from the front surface direction of the first surface 2, and is a first region 10 having a planar shape. And a second region 20 extending in a direction different from the forming direction (defining direction) of the first region 10. The second region 20 is provided so as to surround the periphery of the first region 10, and when viewed from the viewpoint of the second surface 3, that is, the back surface, the glass plate 1 has a three-dimensional shape of a vessel shape. . The cross-sectional view shown in FIG. 1 (a) is a cross-section when cut in a direction parallel to one side of a substantially square shape in plan view. The handling is as follows. In the present specification, “glass plate 1” means “chemically tempered glass” that has been subjected to chemical tempering treatment unless otherwise specified.

The first region 10 includes a portion having the minimum thickness of the glass plate 1 (minimum thickness), and when the minimum thickness of the W _A, leading to 1.1 × W _A thickness from W _A It is a continuous area. In particular, the portion having the minimum thickness W _A is thick as situated near the center of the width in the cross section of the glass plate 1 direction (substantially horizontal direction referred to in the drawings), towards the end from the minimum to have a thickness W _A position Becomes thicker. Then, the thickness was continuously up to the W _A 1.1 × from W _A region as a first region, is a thickness of 1.1 × W _A greater to the end of the glass plate 1 in the second region is there. The second region is, the case where the thickness of the way to the end portion has a portion to be less than 1.1 × W _A. That is, the first region, the glass plate 1, a region ranging from a thickness W _A first to a thickness 1.1 × W _A, the second region, a region other than the first region Say.

In addition, the thickness (plate thickness) of the glass 1 corresponds to the thickness (of the glass) perpendicular to the tangent to the first surface 2. In the case of the glass plate 1 shown in FIG. 1A, a region including the (center) portion where the first surface 2 is flat and has a constant thickness is the first region 10, and is positioned around the first region 10. And a second region 20 having a thickness exceeding 1.1 × W _A. In addition, the 1st area | region 10 may have the surface where the 1st surface 2 curved as long as the 1st surface 2 is not restricted to a planar shape, and the said conditions are satisfy | filled. The glass plates 1 having different thicknesses are also referred to as “uneven glass plates”.

  The glass plate 1 of the present embodiment has a portion where the radius of curvature decreases from the central portion of the first surface 2 and the second surface 3 toward the end surface 21, and the curved portion corresponding to the portion where the radius of curvature is the smallest. 30. The bending part 30 should just exist in at least one surface among the 1st surface 2 and the 2nd surface 3, and the glass plate 1 shown to Fig.1 (a) has the bending part 30 on both surfaces. Thus, by having the curved part 30, the shape of the glass plate 1 from which thickness differs is made.

The second region 20 has a flat end surface 21 that comes into contact with the housing 51 of the portable information terminal 50, for example. The glass 1 is formed by connecting the first surface 2, the end surface 21 (on the left side of the drawing), the second surface 3, and the end surface 21 (on the right side of the drawing) in this order with respect to FIG. The outer edge in the sectional view of FIG. A second region of the glass plate 1 20 has a maximum thickness (maximum thickness) W _B. The maximum thickness W _B refers to the maximum value of the normal direction thickness to a tangent of the first side 2. In the glass plate 1, the end surface 21 corresponds to a linear portion (surface) that connects the first surface 2 and the second surface 3 (in the cross section), but in a later-described embodiment, the end surface 21 has a predetermined shape. Some embodiments have no end face when processed. Moreover, the end surface 21 in the glass plate 1 is the end surface (of flat glass) in the glass plate 1 when the end surface which connects both main surfaces in the flat glass before processing the glass plate 1 exists. If there is a corresponding part, it may be used as the end face 21.

The thickness _{W B} of the thickness _{W A} of the first region 10 second region 20, _{W A} is not less 0.3mm or _more, it is preferable to satisfy the relation of W B / _{W A} ≧ 1.5 More preferably, W _B / W _A ≧ 1.7, and even more preferably W _B / W _A ≧ 1.9. Further, W _B / W _A ≦ 4 is preferable, W _B / W _A ≦ 3.5 is more preferable, and W _B / W _A ≦ 3 is more preferable. When W _B / W _A is 1.5 or more, the strength of the second region 20 is maintained, and when it is 4 or less, molding becomes easy and handling becomes easy. Further, in the glass 1 shown in FIG. 1A, the thickness of the second region 20 is larger than the thickness of the first region 10 (thickness 1.1 × W _A ) in all the second regions. Thick, but not limited to this shape. For example, the glass 1 may have a shape in which the vicinity of the center of the second region 20 is the thickest (thickness: W _B ) and the thickness gradually decreases toward the end surface, as will be described later.

The glass plate 1, the first surface 2, the projected area ratio of the first region 10 to the total projected area when viewed from the direction of the thickness W _A is preferably 0.5 or more, more preferably 0. 6 or more, more preferably 0.7 or more. The projected area ratio is preferably 0.98 or less, more preferably 0.95 or less, and still more preferably 0.9 or less.

The glass plate 1 of the present embodiment has been subjected to chemical strengthening treatment. Thereafter, “L” as the depth of the compressive stress layer formed on the glass plate by the chemical strengthening treatment, “CS” as the compressive stress, and tensile stress. “CT” or the like is used. The compressive stress and tensile stress, "A" of W _A in the first area 10 side, the second region 20 side will be described by adding "B" of W _B.

  FIG. 1B shows an example of use of the glass plate 1, and the glass plate 1 is joined to the casing 51 of the portable information terminal 50 via an adhesive or the like. The second surface 3 of the glass plate 1 may be formed with a recessed portion 4 that is thinner than the other portions. The portable information terminal 50 is provided with a fingerprint sensor 52 and the like. For example, the concave portion 4 is disposed so as to cover from the upper part of the fingerprint sensor 52, thereby facilitating authentication of the fingerprint sensor 52.

  2A to 2C are schematic cross-sectional views showing some embodiments of the glass plate 1. FIG. 2A is a schematic cross-sectional view showing a second embodiment of the glass plate 1, and is a cross-section when cut in a direction parallel to one side of a substantially rectangular shape in plan view. In the second embodiment, the radius of curvature of the curved portion 30 in the first surface 2 is formed larger than that in the first embodiment, and the second region of the first surface 2 relative to the plane of the first region 10 is formed. The inclination of 20 is gentle. That is, in the first embodiment, the second region 20 extending in the vertical direction with respect to the formation direction (for example, the horizontal direction) of the first region 10 is shown, but in the second embodiment, It extends in a tilting direction with a predetermined angle. Note that the curvature of the bending portion 30 and the inclination of the second region 20 are not limited.

  2B and 2C are schematic cross-sectional views showing a state where the portable information terminal 50 is sandwiched between two glass plates 1 from both sides, and FIG. 2B is a diagram illustrating the first embodiment. FIG. 2 (c) shows a case where the second embodiment is adopted. When the end surfaces 21 of the two glass plates 1 are brought into contact with each other, for example, a metal frame or the like may be interposed between the contact surfaces.

FIGS. 3A to 3E are schematic cross-sectional views showing another example of the second embodiment different from the glass plate 1 of FIG. 2A among the embodiments of the glass plate 1. . As for the glass plate 1 shown to Fig.3 (a), both the 1st surface 2 and the 2nd surface 3 have comprised the curved surface shape about the 1st area | region. The second region 20 has a portion gradually thick toward the end of the glass plate 1 is increased, the position shown in FIG. 3 (a) to have a thickness W _B. Moreover, the glass plate 1 shown to Fig.3 (a) has the linear end surface 21 which connects the 1st surface 2 and the 2nd surface 3 (in a cross section). Incidentally, the glass plate 1 shown in FIG. 3 (a), the thickness near the end face 21 is smaller than W _B.

Glass plate 1 shown in FIG. 3 (b), most part of the first region has a constant thickness W _A. The second region 20 has a portion gradually thick toward the end of the first surface 2 of the glass plate 1 is increased, the thickness W _B at a predetermined position shown in FIG. 3 (b) next, the thickness from the position toward the end portion of the first surface 2 is smaller than W _B. In addition, the glass plate 1 shown in FIG.3 (b) is embodiment which the 1st surface 2 and the 2nd surface 3 are connected, and does not have an end surface.

The glass plate 1 shown in FIG.3 (c) is embodiment which deform | transformed the glass plate 1 shown in FIG.3 (b). Specifically, the glass plate 1 shown in FIG. 3 (c), most of the first region has a constant thickness W _A. The second region 20 has a portion gradually thick toward the end of the first surface 2 of the glass plate 1 is increased, the thickness W _B at a predetermined position shown in FIG. 3 (c) next, the thickness from the position toward the end portion of the first surface 2 is smaller than W _B. In addition, the glass plate 1 shown in FIG.3 (c) has the linear end surface 21 which connects the 1st surface 2 and the 2nd surface 3 (in a cross section).

Glass plate 1 shown in FIG. 3 (d), the majority of the first region has a constant thickness W _A. Then, the second region 20, toward the end of the first surface 2 of the glass plate 1 has a portion gradually thickness becomes thicker, the thickness W _B at a predetermined position shown in FIG. 3 (d) next, the thickness from the position toward the end portion of the first surface 2 is smaller than W _B. In the cross section of the glass plate 1 shown in FIG. 3D, the first surface 2 has a “J” -shaped curve, and the second surface 3 also has a “J” -shaped curve. Moreover, the glass plate 1 shown in FIG.3 (d) has the linear end surface 21 which connects the 1st surface 2 and the 2nd surface 3 (in a cross section).

The glass plate 1 shown in FIG.3 (e) is embodiment which deform | transformed the glass plate 1 shown in FIG.3 (d). Specifically, the glass plate 1 shown in FIG. 3 (e), most of the first region has a constant thickness W _A. The second region 20 has a first side second end gradually portion thickness is increased toward the of the glass plate 1, the thickness W _B from the predetermined position shown in FIG. 3 (e) it becomes a shape to maintain a constant thickness W _B to the end portion of the first surface 2. In addition, the glass plate 1 shown in FIG.3 (e) also has the linear end surface 21 which connects the 1st surface 2 and the 2nd surface 3 (in a cross section).

  FIG. 4 shows a third embodiment of the glass plate 1. In the glass plate 1 of the third embodiment, the first region 10 and the second region 20 are flat on the first surface 2. Further, the glass plate 1 of the present embodiment is formed such that the thickness of the entire second region 20 on the second surface 3 is larger than the thickness of the first region 10. In addition, as for the glass 1 of 3rd Embodiment, the curved part 30 exists in the 2nd surface 3 side. The glass plate 1 shown in FIG. 4 also has a linear end surface 21 (in the cross section) that connects the first surface 2 and the second surface 3.

  As long as the glass plate 1 of this embodiment has a composition which can be shape | molded and strengthened by a chemical strengthening process, the glass of various compositions can be used. Specific examples include aluminosilicate glass, soda lime glass, borosilicate glass, lead glass, alkali barium glass, and aluminoborosilicate glass.

Although the composition in particular of the glass plate 1 is not restrict | limited, For example, the following glass compositions are mentioned.
Oxide-based molar percentage display, SiO ₂ 50-50%, Al ₂ O ₃ 2-25%, Li ₂ O 0-20%, Na ₂ O 0.1-18%, K ₂ O 0-10% of MgO 0 to 15% 0 to _5% of _CaO, P 2 _{O 5 0-5%} B 2 _{O 3 0-5%} 0-5% a Y 2 _{O 3} and the ZrO ₂ containing 0-5%.
In addition, it is preferable that the glass plate 1 of this embodiment contains lithium from the point of production efficiency.

  The manufacturing method of the glass plate 1 is not particularly limited. The state of the glass plate 1 before processing, that is, a flat glass plate having a substantially uniform thickness, for example, is charged with a desired glass raw material in a continuous melting furnace, and the glass raw material is preferably heated and melted at 1500 to 1600 ° C. And after refine | purifying, after supplying a shaping | molding apparatus, a molten glass is shape | molded and it can manufacture by annealing.

  The glass plate 1 of the present embodiment is, for example, a flat plate manufactured by various methods such as a down draw method (for example, an overflow down draw method, a slot down method, a redraw method, etc.), a float method, a roll out method, and a press method. This can be realized by processing a glass plate. In the float process, a molten glass substrate is floated on a molten metal such as tin, and a flat glass plate having a substantially uniform thickness and width can be formed by a strict temperature operation. In this embodiment, since it shape | molds in the shape of the three-dimensional-shaped glass plate 1, the bending method which heats a flat glass plate and bends using a pressure difference in the state which contacted the metal mold | die can be applied.

  In addition, although the glass plate 1 of this embodiment can also apply the method of heating a lump-like glass instead of a flat glass plate, and pressing it with a set of uneven | corrugated metal mold | dies, a shaping | molding method is limited to this Not. Further, the glass plate 1 is formed by bending, cutting, mold forming, and the like, and is chemically strengthened after forming, but is not particularly limited by the forming method and the process sequence. Next, specific examples of manufacturing methods (manufacturing methods 1 to 3) for obtaining the glass plate of the present embodiment will be described with reference to the drawings.

<Manufacturing method 1>
9A to 9C are schematic diagrams for explaining an example of a manufacturing method (hereinafter referred to as “manufacturing method 1”) for obtaining a three-dimensional glass plate according to the present embodiment. 9 (a), FIG. 9 (b) and FIG. 9 (c).

  FIG. 9A is a schematic cross-sectional view of a flat glass having a constant thickness, and is also a diagram for explaining “a step of preparing a flat glass”. In this step, in order to finally obtain the three-dimensional glass plate of the present embodiment, a flat glass having a predetermined planar shape (for example, a rectangle) and dimensions is prepared. The thickness of the flat glass having a certain thickness is not particularly limited. For example, for a cover glass of a portable information terminal, the thickness may be in the range of 1.0 to 2.5 mm. A range of 1.3 to 2.0 mm is preferable.

FIG. 9B is a schematic cross-sectional view of a non-thickened glass plate, and the prepared flat glass is thicker than the thickness of the first region in the first region and its periphery (outside) in plan view. is also a diagram explaining the "glass plate uneven thickness step" providing a second region having a thickness W _B. The step includes an example in which the first region is made thinner than the periphery (second region) by using at least one of the method of grinding the first region and the method of polishing the first region. It is done.

  In addition to this, there is an example in which an uneven-thickened glass plate is molded using a molding die (not shown) having a convex mold and a concave mold. In this example, a “heating molding process” is performed in which the molding die is heated to a temperature equal to or higher than the softening point of the glass material (for example, 900 to 950 ° C.) with the flat glass sandwiched between the convex mold and the concave mold. Including. In addition, if the flat glass plate is preheated to a temperature lower than the glass transition temperature, for example, about 500 ° C. before being sandwiched between the convex mold and the concave mold, the temperature difference due to the subsequent heating can be reduced and damage such as cracking can be caused. Since it can reduce, it is preferable. In the heat forming step, the glass plate is unevenly pressed by pressing the molding die in a state where the glass material is softened so that the thickness of the first region is thinner than the thickness of the second region. Furthermore, this example includes a “cooling step” in which the molded state and the glass material are cooled to a temperature lower than the glass transition temperature after the heat forming step, and a predetermined uneven-thickened glass Get a board.

  FIG. 9C is a schematic cross-sectional view of the three-dimensional glass plate of the present embodiment. The uneven glass plate has a convex shape and a concave shape that match the shape of the three-dimensional glass plate. It is also a figure explaining the "bending process" of bending using a shaping die (not shown). This process includes a “heating molding process” in which the molding die is heated to a temperature equal to or higher than the glass transition temperature of the glass material in a state where the unevenly thick glass plate is sandwiched between the convex mold and the concave mold. In the heat molding step, the molding die is pressed in a state where the glass material is softened so as to form a three-dimensional glass plate. Further, in this example, after the heat forming step, the three-dimensional shape of the present embodiment includes a “cooling step” for holding the molded state and cooling the molding die and the glass material to a temperature lower than the glass transition temperature. Get a glass plate. This three-dimensional glass plate has a shape in which the extending direction of the first region and the extending direction of the second region are different.

  This bending process may further include a “surface processing process” in which the surface shape of the three-dimensional glass plate obtained in the cooling process is changed to a desired shape. The surface processing step includes an example in which “curing” (CNC processing) with a grindstone is performed on a curved surface, and precision processing may be performed so that a desired curvature radius is obtained. Further, the surface processing step may include “polishing” for polishing the surface, and the order and number of times of the above “machining” and “polishing” can be arbitrarily implemented.

  In the above polishing process, for example, at least one of lapping, polishing, and etching can be used so that the first region is adjusted to a predetermined thickness. Further, the polishing process may be performed on at least one of the first surface 2 and the second surface 3 in the first region, and is performed only on the first surface 2 for ease of the polishing process. May be. Moreover, the manufacturing method 1 contains the chemical strengthening process process mentioned later after that.

<Manufacturing method 2>
10A to 10C are schematic views for explaining another example of the manufacturing method (hereinafter referred to as “manufacturing method 2”) for obtaining the three-dimensional glass plate according to the present embodiment. 10 (a), 10 (b), and FIG. 10 (c).

  FIG. 10A is a schematic cross-sectional view of a flat glass having a constant thickness, and is also a diagram for explaining “a step of preparing a flat glass”. This step is the same as the “step of preparing flat glass” in the production method 1, and detailed description thereof is omitted.

  FIG. 10B is a schematic sectional view of a three-dimensional glass plate having a constant thickness. A flat glass plate is formed using a molding die (not shown) having a convex mold and a concave mold. It is also a figure explaining the "bending process" bent to the shape of a three-dimensional glass plate. The process is performed by heating the molding die to a temperature equal to or higher than the glass transition temperature of the glass material (for example, glass transition temperature + 100 ° C.) with the flat glass plate sandwiched between the convex mold and the concave mold. Including a heat forming step. Note that the flat glass plate may be preheated so as to have a temperature lower than the glass transition temperature before being sandwiched between the convex mold and the concave mold as in the manufacturing method 1. In the heat molding step, the molding die is pressed in a state where the glass material is softened so as to form a three-dimensional glass plate having a constant thickness. Further, the process includes a “cooling process” in which the molded state and the glass material are cooled to a temperature lower than the glass transition temperature after the thermoforming process, and a three-dimensional shape having a constant thickness is formed. Get a glass plate. The three-dimensional glass plate having a certain thickness has a (virtual) first region and a (virtual) second region that are formed when a “glass plate thickness-reducing step” described later is performed. And obtaining a shape in which the extending direction of the (virtual) first region and the extending direction of the (virtual) second region are different by the bending step. In addition, the broken line shown in FIG.10 (b) is a glass boundary line deleted at the next "glass plate thickness-reduction process."

  FIG. 10C is a schematic cross-sectional view of a three-dimensional glass plate having an uneven thickness, in which a portion including the first region of the three-dimensional glass plate having a certain thickness is thinned. It is also a figure explaining a process. In this process, an example of performing “machining” (CNC processing) with a grindstone so as to thin the portion including the (virtual) first region on the obtained three-dimensional glass plate having a constant thickness. Can be mentioned. Further, the step may include “polishing” for polishing the surface, and the order and number of times of the above “machining” and “polishing” can be arbitrarily performed.

  For the polishing process, for example, at least one of a lapping method, a polishing method, and an etching method can be used so as to adjust a predetermined thickness with respect to a portion including the first region. Further, the polishing process may be performed on at least one of the first surface 2 and the second surface 3 in the portion including the first region. From the ease of polishing process, the polishing process may be performed on the first surface 2. May be implemented only. Moreover, the manufacturing method 2 contains the chemical strengthening process process mentioned later after that.

<Manufacturing method 3>
FIGS. 11A and 11B are schematic views for explaining another example of the manufacturing method (hereinafter referred to as “manufacturing method 3”) for obtaining the three-dimensional glass plate according to the present embodiment. 11 (a) and FIG. 11 (b).

  FIG. 11A is a schematic cross-sectional view of a flat glass having a constant thickness, and is also a diagram for explaining “a step of preparing a flat glass”. This step is the same as the “step of preparing flat glass” in the production method 1, and detailed description thereof is omitted.

  FIG. 11B is a schematic cross-sectional view of a three-dimensional glass plate that is unevenly thickened, and the flat glass plate is formed by using a molding die (not shown) having a convex mold and a concave mold. It is also a figure explaining the "glass plate bending thickness increasing process" bent to the shape of the three-dimensional shape glass plate which became. The step includes a “heating molding step” in which a molding die is heated to a temperature equal to or higher than the softening point of the glass material while the flat glass plate is sandwiched between the convex mold and the concave mold. In the heat forming step, the glass material is formed into a three-dimensional glass plate that has been unevenly pressed by pressurizing the molding die in a softened state. Further, the process includes a “cooling process” in which the molded state and the glass material are cooled to a temperature lower than the glass transition temperature after the thermoforming process, and the three-dimensional shape is unevenly thickened. Get a glass plate. The uneven-thickened three-dimensional glass plate has a first region and a second region outside the first region, and the stretching direction of the first region and the stretching direction of the second region are determined by a bending process. Get different shapes.

  In addition, the glass plate bending uneven thickness process is a “surface processing process” in which, after the cooling process, the surface profile of the three-dimensional glass sheet having an uneven thickness is precisely processed into a desired shape as in manufacturing method 1 described above. May be included. The surface processing step includes at least one of the above-described “machining” and “polishing”, and the order and the number of times can be arbitrarily performed. Moreover, the manufacturing method 3 contains the chemical strengthening process process mentioned later after that.

<Chemical strengthening process>
The glass plate 1 is chemically strengthened glass. Chemically tempered glass is glass having a compressive stress layer formed on the glass surface by ion exchange. For example, a chemical strengthening treatment in which a glass plate is brought into contact with a solution of a metal salt (for example, potassium nitrate) containing metal ions (for example, K ions) having a large ion radius at a temperature lower than the glass transition temperature is applied. By chemical strengthening treatment, ion exchange is performed on the surface of the three-dimensional glass plate, and chemical strengthening proceeds. For example, by replacing alkali metal ions (for example, Li ions and / or Na ions) having a small ionic radius in a glass plate with other alkali ions (for example, Na ions and / or K ions) having a larger ionic radius. A compressive stress layer is formed on the surface of the glass.

  In the glass plate 1 of the present embodiment, for example, a three-dimensional glass plate containing lithium is brought into contact with an inorganic salt composition containing at least one of nitrate and sulfate. In this way, a compression stress layer is formed deeply by including a step of ion exchange between lithium ions contained in the three-dimensional glass plate and ions having a larger ion radius than lithium ions contained in the inorganic salt composition. it can. In this specification, since the inorganic salt composition is used in a dissolved state, it is also simply referred to as “molten salt” and is treated as synonymous.

  The inorganic salt composition contains at least one of nitrate and sulfate. Examples of the nitrate include sodium nitrate and potassium nitrate. Examples of the sulfate include sodium sulfate, potassium sulfate, and sodium sulfate.

  The inorganic salt composition may contain other components as long as the effects of the present invention are not impaired. Examples of other components include sodium chloride, sodium borate, sodium chloride, sodium borate, potassium chloride, potassium borate, potassium carbonate, sodium carbonate, sodium bicarbonate and the like. These may be added alone or in combination of two or more.

  As a method of bringing glass into contact with the inorganic salt composition, a method of applying a paste-like inorganic salt composition to glass, a method of spraying an aqueous solution of an inorganic salt composition onto glass, an inorganic salt composition heated above its melting point Although the method of immersing glass in the salt bath of molten salt is mentioned, Among these, the method of immersing glass in the molten salt of an inorganic salt composition is preferable.

  The chemical strengthening treatment for immersing the glass in the molten salt of the inorganic salt composition is performed, for example, by the following procedure. First, glass is preheated and the molten salt is adjusted to a temperature at which chemical strengthening treatment is performed. Next, the preheated glass is immersed in the molten salt for a predetermined time, and then the glass is pulled up from the molten salt and allowed to cool. The preheating temperature of the glass depends on the chemical strengthening treatment temperature, but is generally preferably 100 ° C. or higher. The chemical strengthening treatment may be performed once or more, and may be performed twice or more under different conditions.

  The temperature at which the chemical strengthening treatment is carried out is preferably not more than the strain point (usually 500 to 600 ° C.) of the glass to be tempered. It is preferably 380 ° C. or higher, more preferably 400 ° C. or higher. In addition, the temperature at which the chemical strengthening treatment is performed is preferably 500 ° C. or less, more preferably 480 ° C. or less, and even more preferably 450 ° C. or less from the viewpoint of suppressing deterioration / decomposition of the molten salt. In addition, as time to perform a chemical strengthening process, 1 to 24 hours are preferable and, as for the contact time to the inorganic salt composition of glass, 2 to 20 hours are more preferable.

  The relationship between the depth of the compressive stress layer, the compressive stress, and the tensile stress of the glass plate 1 of the present embodiment is shown in FIGS. This can be explained by the graph shown in b). Fig.5 (a) is a graph which shows the stress distribution with respect to the thickness of the glass plate obtained by one chemical strengthening process. FIG. 5B is a graph showing the stress distribution with respect to the thickness of the glass plate obtained by two chemical strengthening treatments in which the conditions of the chemical strengthening treatment are changed in the first and second stages.

  As shown in FIGS. 5 (a) and 5 (b), the glass plate 1 has a compressive stress layer on at least the first surface 2, which is the surface on the side touched by the user's hand, and a tensile stress is formed inside the glass. Is formed. Here, the depth direction from the glass surface (first surface 2) is x (unit [μm]), and the compressive stress corresponding to x is σ. The distance from the glass surface at which the compressive stress σ becomes zero is the compressive stress depth L (unit [μm]), the internal tensile stress is CT (Center Tension: unit [MPa]), and the surface compressive stress σ is CS. (Compressive Stress: unit [MPa]).

The glass plate 1 of this embodiment includes a compressive stress layer in the depth direction from the first surface 2, than the depth L _A compressive stress layer in the first region 10 of the compression stress layer of the second region 20 intensity at the second region 20 by direction of depth L _B having a deep portion increases. The compressive stress layer in the second region 20 may be provided in the depth direction from the second surface 3 or the end surface 21 in addition to the first surface 2, but unless otherwise specified, the depth L _B of the compressive stress layer, the depth of the compressive stress layer from the first surface 2. In this specification, [dσ / dx] _{x = L} (unit [MPa / μm]) indicates the slope of the curve of the compressive stress value σ at the depth L of the compressive stress layer. When this inclination is small, the difference in the depth of the compressive stress layer due to the difference in the thickness of the glass becomes large.

In the glass plate 1 of this embodiment, the slope [dσ / dx] _{x = L} of the compressive stress value σ in the depth direction from the surface is preferably −2 or more ([dσ / dx] _{x = L} ≧ −2). ), The compressive stress layer becomes deep, and the impact resistance of the glass plate 1 becomes strong. [Dσ / dx] _{x = L} is more preferably −1 or more, and further preferably −0.5 or more. [Dσ / dx] _{x = L} is a negative value.

  When the glass plate 1 is used as, for example, a cover glass of the portable information terminal 50, the glass plate 1 may be damaged due to dropping of the portable information terminal 50, impact from the outside, or the like. At this time, the glass plate 1 is more susceptible to a strong impact in the second region 20 than in the first region 10, and therefore, a phenomenon that the glass plate 1 is damaged starting from the second region 20 is likely to occur. Therefore, the glass plate of this embodiment can reduce breakage because the strength level of chemical strengthening in the second region is high.

In the glass plate 1 of the present embodiment, even when the second region 20 is formed thicker than the first region 10 (W _B > W _A ), the depth of the compressive stress layer is increased ( L _B > L _A ) can be formed. The glass plate 1 of this embodiment, the entire glass plate is reinforced, in particular, can increase the depth L _B of the compressive stress layer in the second region 20, thereby also improving the impact resistance at the periphery of the glass plate 1 . Therefore, the glass plate 1 is resistant to dropping and impact, and is suitable as a cover glass plate for the portable information terminal 50, for example.

The glass plate 1 of this embodiment, the depth of the compressive stress layer from the first surface 2 at the position of the thickness W _A of the first region 10 and L _A, the thickness W _B of the second region 20 When the depth of the compressive stress layer from the first surface 2 at the position is L _B , L _A and L _B are 80 μm or more, and it is preferable that the relational expression L _B / L _A ≧ 1.2 is satisfied. L _A and L _B are more preferably 90 μm or more, and still more preferably 100 μm or more. By satisfying the relational expression of L _B / L _A ≧ 1.2, the depth of the compressive stress layer in the second region 20 becomes deeper than the depth of the first region 10, and the strength of the second region 20 is increased. It improves and becomes hard to break. L _B / L _A is more preferably 1.3 or more, and still more preferably 1.4 or more. The upper limit of L _B / L _A is not particularly limited, but is typically preferably 3 or less, and more preferably 2 or less.

The glass plate 1 of this embodiment, the tensile stress at the position of the thickness W _A of the first region 10 and CT _A, when the tensile stress at the position of the thickness W _B of the second region 20 was set to CT _B In addition, it is preferable that CT _A and CT _B satisfy the relational expression of | CT _A |> | CT _B |. When the relational expression | CT _A |> | CT _B | is satisfied, the tensile stress that causes cracking in the second region 20 is lower than that in the first region 10, and damage due to impact or the like can be reduced.

The glass plate 1 of this embodiment, the depth _{L A} compressive stress layer in the first region 10, the thickness _{W A} of the first region _10, L A / _{W A} ≧ 0.15 relation It is preferable that L _A / W _A ≧ 0.17, and more preferably L _A / W _A ≧ 0.19. When L _A / W _A ≧ 0.15, the impact resistance can be improved. The upper limit of L _A / W _A is not particularly limited, but is typically 0.25 or less.

  The compressive stress (CS) on the glass surface and the depth (DOL) of the compressive stress layer can be measured by a stress measuring device such as a scattered light photoelastic stress meter. The principle of the scattered light photoelastic stress meter (model SLP-1000: Orihara Seisakusho) used in Examples described later will be described with reference to FIG.

  The stress measurement apparatus 100 includes a laser light source 101, a polarizing member 102, a polarization phase difference variable member 103, a light supply member 104, a light conversion member 105, an image sensor 106, an arithmetic unit 107, and an optical wavelength selection member. 108. A measured object 120, which is a glass plate to be measured, is installed on the light supply member 104, and laser light 110 emitted from the laser light source 101 is incident on the measured object 120 and measurement is performed. The polarization phase difference variable member 103 changes the polarization phase difference of the laser light 110 by one or more wavelengths with respect to the wavelength of the laser light 110.

  The image sensor 106 captures a plurality of images of the scattered light emitted when the laser beam 110 whose polarization phase difference is changed is incident on the measurement object 120 at predetermined time intervals, and acquires a plurality of images. The stress measurement apparatus 100 includes a calculation unit (not shown). The calculation unit measures a periodic luminance change of scattered light using a plurality of images, calculates a phase change of the luminance change, and based on the phase change. The stress distribution in the depth direction from the surface of the measurement object 120 is calculated.

  Further, the calculation means 140 of the stress measurement apparatus 100 includes a luminance change measurement means 141, a phase change calculation means 142, and a stress distribution calculation means 143, as shown in FIG. 6B.

The stress measuring apparatus 100 measures in the following process order.
(1) A polarization phase difference process (step S201) in which the laser beam 110 is polarized and phase-differed by the polarization phase difference variable member 103.
(2) A light supply step of supplying the laser beam 110 to the measurement object 120 by the light supply member 104 (step S202).
(3) An imaging step of imaging the scattered light from the measurement object 120 with the imaging device 106 (step S203).
(4) A luminance change measurement step for measuring a periodic luminance change from the scattered light imaged by the computing unit 107 (step S204).
(5) A phase change calculation step (step S205) in which the calculation unit 107 calculates the phase change.
(6) A stress distribution calculation step (step S206) in which the calculation unit 107 calculates the stress distribution.

  Here, based on the experimental conditions (Table 1) of the examples and comparative examples, the measurement results (Table 2), and the diagram showing the relationship between the depth of the compressive stress layer and the plate thickness (FIG. 7), the glass plate of the present embodiment The advantage of 1 will be described. In Table 1, “-” indicates that the second-stage chemical strengthening treatment is not performed. Moreover, the graph which compared the CS value and DOL value about the 1st area | region 10 and the 2nd area | region 20 about Example 4 was created.

(Examples 1-8)
In Examples 1 to 8, a glass plate containing Li ₂ O, Al ₂ O ₃ , and SiO ₂ (shown as LiAlSi in Table 2) was subjected to chemical strengthening treatment under the conditions shown in Table 1 to prepare a sample. . Specifically, in Examples 1 to 8 and Comparative Examples 1 to 3 to be described later, the extending direction of the second region 20 with respect to the extending direction of the first region 10 is substantially orthogonal as shown in FIG. And a glass plate having an end surface 21 substantially parallel to the second surface 3. In addition, the horizontal width (thickness) of the portion extending in the vertical direction in the second region 20 of the glass plate 1 in FIG. As shown in Table 2, Examples 1 to 3, the thickness _{W A} of the first region 10 is 0.6 mm, the thickness _{W B} of the second region 20 is located at 1.2~1.6mm , examples 4 8, the thickness _{W a} of the first region 10 is 0.8 mm, the thickness _{W B} of the second region 20 is 1.2 to 2.0 mm. In Table 2, the depth L, the inclination, the CS, CT, and DOL (in the first region) of the compressive stress layer all indicate values on the first surface 2.

In Examples 1 to 8 and Comparative Examples 1 to 3 to be described later, chemically strengthened glass plates were produced based on “Production Method 2”. The following method was used for the shape of the unevenly three-dimensional glass plate before chemical strengthening treatment.
(1) Step of preparing flat glass First, flat glass having a plate thickness of 0.7 mm, 1.2 mm, 1.4 mm, 1.6 mm, and 2.0 mm was prepared using the float method. As the glass material, DT-STAR (transition temperature: 549 ° C., strain point: 508 ° C.) manufactured by AGC Corporation was used.
(2) Glass plate bending uneven thickness step Next, as a mold having an outer dimension of 180 mm x 120 mm x 30 mm, a convex mold and a concave mold having substantially the same volume are used. In the state where the prepared flat glass was sandwiched, the mold was heated until the viscosity coefficient of the glass reached 10 ^9.5 [Pa · s]. Next, while maintaining the temperature, the glass was pressed and molded so that the maximum value of the press pressure was 0.55 MPa. Then, in the state which pressed the glass with the maximum value of 0.5 MPa of press pressure, it cooled to the strain point of glass, and stood to cool to normal temperature. The three-dimensional glass plate obtained at this time has a substantially rectangular shape of 150 mm × 80 mm in plan view (from the normal direction of the surface of the first region), and has a surface (first surface) over the entire circumference of the first region. The curvature radius of the curved portion of the first surface 2) was 5 mm. The three-dimensional glass plate has a flat portion with a radius of curvature of more than 100 mm at the center of the surface (first surface 2), and the bending depth (the length from the first surface 2 to the end surface 21) is approximately. The thickness was 3.2 mm.
(3) Surface processing step Finally, the three-dimensional glass plate after being allowed to cool to room temperature is ground by CNC processing for a predetermined thickness with respect to the flat portion, and a second region having a curved surface is formed. Polishing was performed so as to obtain a predetermined shape. Thereafter, a three-dimensional glass plate was polished and smoothed by using a cerium oxide abrasive to polish the first surface 2, the second surface 3, the end surface 21 and all the surfaces. The thickness in each area | region of the produced three-dimensional glass plate of Examples 1-8 and Comparative Examples 1-3 is as showing in Table 2.

As shown in Table 1, as the conditions for the chemical strengthening treatment, Example 1 was obtained by immersing in NaNO ₃ 100% molten salt at 450 ° C. for 2.5 hours in the first stage, and then in the second stage, KNO. ₃ Dipped in 100% molten salt at 415 ° C. for 2 hours. The conditions in Example 2 and Example 3 were the same as in Example 1. Example 4 is the same as Example 1 in the first step, but in the second step, it was immersed in molten salt of 100% KNO ₃ at 425 ° C. for 1.5 hours. Example 5, Example 6 and Example 8 were made the same conditions as Example 4. Example 7 was the same as Example 4 except that the first stage immersion time was 20 hours.

(Comparative Example 1)
In Comparative Example 1, a glass plate containing Al ₂ O ₃ and SiO ₂ (shown as AlSi in Table 2) was subjected to chemical strengthening treatment under the conditions shown in Table 1 to prepare a sample. As shown in Table 2, the thickness _{W A} of the first region 10 of Comparative Example 1 is 0.6 mm, the thickness _{W B} of the second region 20 is 1.2 mm. As shown in Table 1, as a condition for chemical strengthening treatment, Comparative Example 1 was immersed in a mixed molten salt of 97% by mass of KNO ₃ and ₃ % by mass of NaNO ₃ at 435 ° C. for 4.5 hours, and the second stage was performed. I did not.

(Comparative Example 2)
In Comparative Example 2, a glass plate containing Li ₂ O, Al ₂ O ₃ , and SiO ₂ was subjected to chemical strengthening treatment under the conditions shown in Table 1 to prepare a sample. As shown in Table 2, the thickness _{W A} of the first region 10 of Comparative Example 2 is 0.6 mm, the thickness _{W B} of the second region 20 is 1.2 mm. As shown in Table 1, Comparative Example 2 was immersed in a molten salt of 100% KNO ₃ at 410 ° C. for 73 hours, and the second step was not performed.

(Comparative Example 3)
In Comparative Example 3, a sample was prepared by subjecting a glass plate containing Li ₂ O, Al ₂ O ₃ , and SiO ₂ to chemical strengthening treatment under the conditions shown in Table 1. As shown in Table 2, the thickness _{W A} of the first region 10 of Comparative Example 3 is 0.6 mm, the thickness _{W B} of the second region 20 is 0.7 mm. As shown in Table 1, as a condition for the chemical strengthening treatment, Comparative Example 3 was immersed in a molten salt of NaNO ₃ 100% at 450 ° C. for 2.5 hours in the first stage and then KNO in the second stage. ₃ Dipped in 100% molten salt at 415 ° C. for 2 hours.

About the sample of the Example and comparative example produced on the above conditions, a scattered light photoelastic stress meter (SLP-1000 by Orihara Manufacturing Co., Ltd.), a surface stress meter (FSM-6000 by Orihara Manufacturing Co., Ltd.), or a birefringence imaging system Compressive stress CS, tensile stress CT, compressive stress layer depth L, and compressive stress value σ are measured using (Abrio-IM manufactured by Tokyo Instruments Co., Ltd.), and the slope [dσ / dx] _{x = L} is calculated. did. The results are shown in Table 2, FIG. 7 and FIG. In FIG. 7, the horizontal axis represents the glass thickness, the vertical axis represents the compression stress layer depth, and the glass thickness is changed under the same conditions as the optimum chemical strengthening treatment conditions when the glass has a predetermined thickness. It is the graph which showed the relationship between the thickness of glass, and the depth of a compressive-stress layer when it was made to do. In FIG. 7, the solid line represents the relationship in the optimum chemical strengthening treatment condition when the glass plate thickness is 0.6 mm, and the broken line represents the optimum chemical strengthening treatment condition when the glass plate thickness is 0.8 mm. The relationship was shown.

  The CS of the second region 20 in Example 4 of Table 2 was 980 (MPa), CT was 40 (MPa), and DOL was 190 (μm). Note that CS, CT, and DOL of the second region 20 are all values on the first surface 2. FIG. 7 is a graph showing the relationship between the depth of the compressive stress layer and the thickness of the second region 20. FIG. 8 is a graph showing the relationship between the depth direction of the first region 10 and the second region 20 and the compressive stress CS in Example 4.

As shown in Table 2 and FIG. 8, in Example 4, the depth L of the compressive stress layer was increased, and the depth L of the compressive stress layer was reliably increased even when the thickness W was increased. Even when the second region 20 is formed thicker than the first region 10, the depth of the compressive stress layer in the second region 20 can be increased. This shows the result of chemically strengthening the first region and the second region simultaneously under the same conditions. Further, the depth _{L A} compressive stress layer in the first region 10, the depth _{L B} of the compressive stress layer in the second region _20, to satisfy the relationship of L B / _{L A} ≧ 1.2 I understand.

Since the depth of the compressive stress layer in the second region 20 is deeper than the depth of the first region 10 and L _A and L _B satisfy the relational expression L _B / L _A ≧ 1.2, the second region 20 becomes stronger and is hard to break. As a result of evaluating the strength of the glass plate, the example showed higher strength than the comparative example, and in particular, the generation of cracks starting from the end portion and the end surface was suppressed.

Further, as shown in FIG. 7, it can be seen that in Example 4, the compressive stress layer becomes deeper in the first region 10 as the thickness W increases. Relationship between the thickness W _B of the thickness W _A and the second region 20 of the first region 10 is not much different as in Comparative Example 3 (Ratio 1 = 1.17), the depth of the compressive stress layer There is also little change in the ratio (ratio 2 = 1.11). However, when the ratio 1 (W _B / W _A ) is 1.5 or more as in Examples 1 to 8, the depth ratio 2 (L _B / L _A ) of the compressive stress layer increases, and the glass plate The strength of 1 is further improved.

Further, from Table 2, the compression stress layer [dσ / dL] _{x = L} is gentle as in Examples 1 to 8 and satisfies [dσ / dL] _{x = L} ≧ −2. It can be seen that the depth L of the glass becomes deeper, and the impact resistance of the glass plate 1 is further improved and becomes stronger.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimension, numerical value, form, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

  The chemically strengthened glass plate and the method for producing the same according to the present invention are optimal for the field of portable information terminals, substrates and the like where a glass plate having high impact resistance is required.

DESCRIPTION OF SYMBOLS 1 Glass plate 2 1st surface 3 2nd surface 10 1st area | region 20 2nd area | region 21 End surface 30 Curved part CT Tensile stress CS Compressive stress L Compressive stress layer depth W Thickness σ Compressive stress value

Claims (16)

The first side,
A second surface facing the first surface;
A first region having a thickness in a normal direction of a tangent to the first surface and having a predetermined thickness; and a second region including a region thicker than the thickness of the first region. Prepared,
Said first region, when the thinnest part thickness W _A of the thickness of a continuous region up to a thickness of 1.1 × W _A from the thickness W _A,
It said second region is a region having a thickness of 1.1 × W _A greater than the thickness of the thickest portion and W _B,
The depth of the compressive stress layer in the second region has a portion formed deeper than the depth of the compressive stress layer in the first region;
In the first region and the second region, the depth of the compressive stress layer is not less 80μm or more, the depth of the compressive stress layer position of the thickness W _A and L _A, the thickness W _{B A} chemically strengthened glass plate in which the depth of the compressive stress layer at the position is L _B and L _A and L _B satisfy the relational expression L _B / L _A ≧ 1.2. Wherein _{W A} is not less 0.3mm or _{more, W} B / W _A ≧ 1.5 chemically strengthened glass plate according to claim 1, satisfying the relational expression.   3. The chemically strengthened glass sheet according to claim 1, wherein a projected area ratio of the first region to a total projected area on the first surface is 0.5 or more. In the first region and the second region,
The depth direction from the first surface is x,
The compressive stress value corresponding to the depth direction from the first surface is σ,
When the depth at which the compressive stress value σ becomes zero is the depth L of the compressive stress,
The chemical tempered glass sheet according to any one of claims 1 to 3, wherein a relational expression representing an inclination of the compressive stress satisfies [dσ / dx] _{x = L} ≧ -2. Said _{L A,} the _{W A} and _is chemically strengthened glass sheet according to claim 1, satisfying the relationship of L _A / _W A ≧ 0.15.   The chemically strengthened glass sheet according to any one of claims 1 to 5, wherein the second region extends in a direction different from a forming direction of the first region.   7. The chemically strengthened glass plate according to claim 1, wherein at least one of the first surface and the second surface has a curved portion having a minimum radius of curvature.   The chemically strengthened glass plate according to claim 1, wherein at least lithium is contained.   The portable information terminal which has a chemically strengthened glass plate of any one of Claims 1-8. Preparing a flat glass having a constant thickness;
In the planar view of the flat glass, the first region and the second region outside the first region have a portion where the thickness of the first region is thinner than the thickness of the second region. In this way, a glass plate uneven thickness forming step for forming the uneven thickness glass plate,
In the uneven-thickened glass plate, a bending step of forming a three-dimensional glass by changing the stretching direction in the first region and the stretching direction in the second region;
The three-dimensional shape glass in the first region and the second region, the depth of the compressive stress layer is not less 80μm or more, the depth of the compression stress layer of the first region and L _A, the _A chemical strengthening process including a chemical strengthening treatment step in which the depth of the compressive stress layer in the second region is L _B and L _A and L _B perform chemical strengthening satisfying a relational expression of L _B / L _A ≧ 1.2. A method for producing a tempered glass sheet.   The manufacturing method of the chemically strengthened glass plate of Claim 10 including the grinding | polishing process of grind | polishing the surface of the said three-dimensional shape glass between the said bending process and the said chemical strengthening process process.   In the glass plate uneven thicknessing step, the flat glass plate is heated to a temperature equal to or higher than the transition point of the glass material and molded by a mold, and after the thermoforming step, the temperature is lower than the transition point of the glass material. The manufacturing method of the chemically tempered glass board of Claim 10 or 11 including the cooling process cooled to 2nd.   The glass plate uneven thicknessing step includes at least one of a step of polishing the first region of the flat glass and a step of grinding the first region of the flat glass. The manufacturing method of the chemically strengthened glass plate of description. Preparing a flat glass having a constant thickness;
Regarding the first region and the second region outside the first region in plan view of the flat glass, the stretching direction in the first region is different from the stretching direction in the second region. Bending process to form a three-dimensional glass;
A glass plate thickness-increasing step for forming the unevenly-thickened three-dimensional shape glass so as to have a portion where the thickness of the first region of the three-dimensional shape glass is thinner than the thickness of the second region; ,
The three-dimensional shape glass in the first region and the second region, the depth of the compressive stress layer is not less 80μm or more, the depth of the compression stress layer of the first region and L _A, the _A chemical strengthening process including a chemical strengthening treatment step in which the depth of the compressive stress layer in the second region is L _B and L _A and L _B perform chemical strengthening satisfying a relational expression of L _B / L _A ≧ 1.2. A method for producing a tempered glass sheet. Preparing a flat glass having a constant thickness;
For the first region and the second region outside the first region in plan view of the flat glass, the stretching direction in the first region is different from the stretching direction in the second region. The thickness of the first region has a portion that is thinner than the thickness of the second region, and a glass plate bending uneven thickness forming step for forming the uneven three-dimensional glass,
The three-dimensional shape glass in the first region and the second region, the depth of the compressive stress layer is not less 80μm or more, the depth of the compression stress layer of the first region and L _A, the Including a chemical strengthening treatment step in which the depth of the compressive stress layer in the second region is L _B and L _A and L _B perform chemical strengthening satisfying a relational expression of L _B / L _A ≧ 1.2,
The glass plate bending uneven thickness step is lower than the glass material transition point after the heat molding step and the thermoforming step, in which the flat glass plate is heated to a temperature above the glass material transition point and molded by a mold. The manufacturing method of a chemically strengthened glass plate including the cooling process cooled to temperature.   The manufacturing method of the chemically strengthened glass plate of Claim 15 including the grinding | polishing process which grind | polishes the surface of the said three-dimensionally shaped glass between the said glass plate bending uneven thickness process and the said chemical strengthening process.

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