WO2014141981A1

WO2014141981A1 - Display device, display device manufacturing method, touch panel, and touch panel manufacturing method

Info

Publication number: WO2014141981A1
Application number: PCT/JP2014/055709
Authority: WO
Inventors: 長谷川　聡; 都築　達也; 直樹三田村; 村本　正; 松田　裕
Original assignee: セントラル硝子株式会社
Priority date: 2013-03-15
Filing date: 2014-03-06
Publication date: 2014-09-18
Also published as: TW201442969A; JP6197317B2; JP2014178640A; CN104718520A

Abstract

The purpose of the present invention is to provide a display device having a cover glass in which a touch sensor is formed and also having a high degree of safety and high end face strength, and to provide a manufacturing method for the display device. This display device has a display panel, and a touch panel attached to the front surface of the display panel. The display device is characterized in that: the touch panel comprises a cover glass, which has a first surface facing the front surface of the display panel and a second surface on the side opposite the first surface, and a touch sensor formed on the first surface of the cover glass; the cover glass is chemically strengthened; the surface compressive stress of the cover glass is 600-900MPa, and the compressive stress layer depth is 5-20μm; and the cover glass has a clean-cut surface that is substantially perpendicular to the first surface, and a chamfered surface that is formed on the edge of the second surface.

Description

Display device, display device manufacturing method, touch panel, and touch panel manufacturing method

The present invention relates to a display device, a method for manufacturing a display device, a touch panel, and a method for manufacturing a touch panel. For example, the present invention relates to an input / output integrated display device that enables handwriting input with a finger, a pen, or the like.

A display device in which a touch panel is provided on a display panel such as a flat panel display panel such as a liquid crystal panel or an organic EL panel so that characters, patterns, etc. can be input by handwriting and the input content can be displayed on the display panel. It is widely used in various electronic devices such as mobile devices such as mobile phones and car navigation systems.

The display device is provided with a transparent protective plate on the viewing side in order to maintain local display quality by avoiding local pressure generated during input. And it is preferable that a glass plate is used for this protection board from surface, such as intensity | strength and durability. In recent years, due to demands for weight reduction and thinning of mobile devices and the like, the above-described display device is also required to be thin, and accordingly, the thickness of the protective glass plate is also required to be reduced. However, as the glass becomes thinner, the strength decreases, and the protective glass (cover glass) itself may be broken due to dropping or the like, which makes it impossible to protect the display device. Therefore, chemical tempered glass is generally used for the cover glass (see, for example, Patent Document 1 and Patent Document 2).

Also, a touch panel in which a cover glass and a touch sensor are integrated is shown in order to cope with the thinning of the structure of the touch panel (see, for example, Patent Document 3).

Furthermore, as a touch panel manufacturing method, a technique has been proposed in which a plurality of touch panels are efficiently manufactured by forming multiple touch sensors on a large transparent glass substrate and individually cutting in a subsequent process (for example, (See Patent Document 4).

Special table 2010-527892 JP 2010-275126 A JP 2012-88946 A JP 2008-33777 A

Regarding chemically strengthened glass that can be used as a cover glass, Patent Document 1 and Patent Document 2 disclose specific glass compositions, but do not disclose a specific configuration of a display device.

Regarding a method of individually cutting from a large glass substrate on which a touch sensor is formed with multiple faces, a method of cutting by chemical etching is disclosed in Patent Document 3, and a method of cutting by a diamond cutter is disclosed in Patent Document 4. However, in the method of Patent Document 3, since cutting is performed from both sides of the cover glass by etching, masking is performed so that the touch sensor portion is not etched, and cleaning and waste liquid treatment after etching must be performed. Leads to longer and more complicated processes. Moreover, in the method of patent document 4, since the surface by the side of a touch sensor is cut with the diamond cutter, the cutting groove trace of a diamond cutter will remain. The cut groove marks are caused by contact between the glass and a mechanical tool such as a diamond cutter, and therefore, the glass is finely scratched and integrated with the front and back. That is, in the state where cut groove marks remain in the glass, high end surface strength (strength of the glass end surface) cannot be obtained.

Thus, in the method of efficiently producing a plurality of touch panels from one large glass substrate, the chemically tempered glass is post-cut, so that the strength of the glass end face is independent of the degree of chemical strengthening, the cutting method or the end face. It depends on the processing method. In order to obtain high end surface strength, it is necessary to finish the end surface into a so-called “clean cut surface”. The clean cut surface is, for example, a non-scribe side cut surface or a laser scribe cut surface among cut surfaces obtained by dividing a scribe by a machine tool.

However, the clean cut surface has no chipping or micro cracks, so it has high strength, but it has sharp edges, so it tends to cause hand or finger incision, and there is a problem with safety. there were. Therefore, chamfering is usually applied to the end face. That is, conventionally, the advantage of high end face strength due to the clean cut surface has not been utilized.

In view of the above problems, the present invention provides a display device provided with a cover glass having a high safety and high end face strength, and a method for manufacturing the display device, in a cover glass on which a touch sensor is formed. The purpose is to do. Another object of the present invention is to provide a touch panel used in the display device and a method for manufacturing the touch panel.

The display device of the present invention is a display device comprising a display panel and a touch panel attached to the front surface of the display panel, wherein the touch panel is a first surface facing the front surface of the display panel, and A cover glass having a second surface opposite to the first surface; and a touch sensor formed on the first surface of the cover glass, wherein the cover glass is a chemically strengthened glass. The cover glass has a surface compressive stress of 600 to 900 MPa and a compressive stress layer depth of 5 to 20 μm. The cover glass has a clean cut surface substantially perpendicular to the first surface, and It has a chamfered surface formed at the edge of the second surface.

In the display device of the present invention, a touch panel is attached to the front surface of the display panel, and the touch panel is formed on a cover glass and a first surface of the cover glass (a surface facing the front surface of the display panel). Touch sensor. And in the display apparatus of this invention, the cover glass which comprises a touchscreen has the characteristics.

In the display device of the present invention, chemically strengthened glass is used as the cover glass, and the cover glass has a surface compressive stress of 600 to 900 MPa and a compressive stress layer depth of 5 to 20 μm.

Since the surface compressive stress of the cover glass is 600 to 900 MPa, the cover glass is excellent in strength. When the surface compressive stress is less than 600 MPa, the average strength of the glass is lowered, and the glass is broken due to an impact caused by contact with a high-hardness member or an impact caused by dropping. On the other hand, when the surface compressive stress exceeds 900 MPa, the cutting property of the glass deteriorates, so that the internal tensile stress formed with respect to the surface compressive stress also increases particularly in a thin glass, and the glass is broken when a crack is introduced. There is a fear.

Since the cover glass has a compressive stress layer depth of 5 to 20 μm, the cover glass is excellent in scratch resistance and cutting workability. When the depth of the compressive stress layer is less than 5 μm, it is not possible to prevent the glass from being broken due to micro cracks called “Griffith flow” generated before chemical strengthening. Moreover, since the compressive-stress layer depth is less than 5 micrometers, since it is inferior to scratchability, it cannot endure use on a market. On the other hand, when the compressive stress layer depth exceeds 20 μm, it becomes difficult to divide the glass along the scribe line, that is, to cut the glass.

The cover glass has a clean cut surface substantially perpendicular to the first surface and a chamfered surface formed at the edge of the second surface. This point is the characteristic of the display device of the present invention. It is a big feature.

First, since the clean cut surface is formed substantially perpendicular to the first surface of the cover glass, high end surface strength can be obtained. Also, when the cover glass surface is pressed by an input operation with a finger or pen, tensile stress is applied to the glass surface on the touch sensor side (first surface side), so the end surface strength on the touch sensor side is high. Is preferred.

The second surface of the cover glass corresponds to the outermost side of the display device, and is a surface that is directly touched and operated with a hand or a finger. By chamfering the edge of the second surface, the display device can be used safely without causing a hand or finger cut.

In the above cover glass, it is desirable to make the glass plate as thin as possible in order to reduce the weight of final products such as mobile devices and to secure the capacity of devices such as batteries, but if it is too thin, the stress generated by the glass bending will be generated. It gets bigger. On the other hand, if the plate thickness is too thick, the apparatus weight increases and the visibility of the display device decreases. Therefore, in the display device of the present invention, the cover glass preferably has a thickness of 0.3 to 3 mm.

In the display device of the present invention, the cover glass has two types of stress patterns, a stress distribution pattern A on the glass surface side and a stress distribution pattern B on the glass inner side, in the compressive stress layer. and in the case of approximating the the stress pattern B respectively a linear function, when the inclination of the stress pattern a and S _a, the slope of the stress pattern B and S _B, satisfy the relationship of S _a> S _B, and The interference fringes of the cover glass are observed using a surface stress meter whose observation principle is the optical waveguide effect, the distance between the _first interference fringe and the second interference fringe from the glass surface is r ₁ , and 2 from the glass surface. When the distance between the third interference fringe and the third interference fringe is r ₂ , and the distance between the third interference fringe and the fourth interference fringe from the glass surface is r ₃ , r ₂ / r ₁ and r ₃ / Although at least one of r _2, Preferably satisfies the .3 to 0.7.

In general, it is considered that the higher the value of the surface compressive stress, the higher the value of the internal tensile stress necessary to maintain a balance with the integrated value of the compressive stress in the compressive stress layer.
The cover glass has two kinds of stress patterns in the compressive stress layer, that is, a stress distribution pattern A on the glass surface side and a stress distribution pattern B on the glass inner side, and satisfies the relationship of S _A > S _B described above. In this case, the integrated value of the compressive stress in the compressive stress layer can be reduced while having a high surface compressive stress value.

Further, as an index for evaluating the inclination of the stress pattern, the above ratios r ₂ / r ₁ and r ₃ / r ₂ are evaluated, and at least one of r ₂ / r ₁ and r ₃ / r ₂ is 0.3. When ˜0.7 is satisfied, the stress rapidly decreases on the glass surface side, and the rate at which the stress decreases decreases toward the glass inner side. This can approximately represent the change in the slope of the stress pattern described above. Therefore, the relationship of S _A > S _B can be satisfied, and the integrated value of the compressive stress in the compressive stress layer can be reduced. When the ratio of r ₂ / r _{1 and} the ratio of r ₃ / r ₂ is less than 0.3, the stress tends to decrease too rapidly on the glass surface side, and microcracks that may occur during use of the cover glass Therefore, there is a concern that the strength may decrease. On the other hand, when the ratio r ₂ / r _{1 and} the ratio r ₃ / r ₂ exceed 0.7, the inclination of the stress pattern becomes nearly constant. That is, the degree of decrease in compressive stress from the glass surface toward the inside tends to be more linear. Therefore, it becomes difficult to obtain the effect of reducing the integrated value of the compressive stress in the compressive stress layer.

In the display device of the present invention, the arithmetic average roughness Ra of the clean cut surface of the cover glass is preferably 0.07 μm or less, and the maximum height roughness Rz is preferably 0.70 μm or less.

In the display device of the present invention, it is preferable that a machining allowance of the cover glass on the chamfered surface is 3 to 35% of the thickness of the cover glass.

A display device manufacturing method according to the present invention is a display device manufacturing method including a display panel and a touch panel attached to the front surface of the display panel, and is a chemically strengthened glass plate, which is a surface compression A step of preparing a glass plate having a stress of 600 to 900 MPa and a compressive stress layer depth of 5 to 20 μm; and a touch sensor on at least the first region and the second region on the first surface of the glass plate. The glass plate so that each of the forming step and the first region and the second region are divided and a clean cut surface substantially perpendicular to the first surface of the glass plate is formed. Cutting at least two cover glasses having the touch sensor formed on the first surface, and a second side of the cover glass opposite to the first surface. A step of chamfering the edge of the surface, the first surface of the cover glass, characterized in that it comprises a step of disposing so as to face the front surface of the display panel.

In the above method, since a plurality of touch sensors are formed on one large glass plate and then the glass plate is divided, a plurality of touch panels can be efficiently manufactured. Moreover, since the clean cut surface is formed substantially perpendicular to the surface (first surface) on the touch sensor side, the end surface strength on the touch sensor side can be increased. Thus, the display device of the present invention can be efficiently manufactured.

In the method for manufacturing a display device of the present invention, the cover glass preferably has a thickness of 0.3 to 3 mm.

In the method for manufacturing a display device of the present invention, the cover glass has two types of stress patterns in the compression stress layer, that is, a stress distribution pattern A on the glass surface side and a stress distribution pattern B on the glass inner side, in the case of approximating the stress pattern a and the stress pattern B respectively a linear function, when the inclination of the stress pattern a and S _a, the slope of the stress pattern B and S _B, the relationship between S _a> S _B The interference fringes of the cover glass are observed using a surface stress meter that satisfies the optical waveguide effect as the observation principle, and the distance between the _first interference fringe and the second interference fringe from the glass surface is r ₁ , glass When the distance between the second interference fringe and the third interference fringe from the surface is r ₂ , and the distance between the third interference fringe and the fourth interference fringe from the glass surface is r ₃ , r ₂ / r ₁ and When the least of _r ₃ / r ₂ One, but preferably satisfies 0.3 to 0.7.

In the manufacturing method of the display device of the present invention, the arithmetic average roughness Ra of the clean cut surface of the cover glass is 0.07 μm or less, and the maximum height roughness Rz is 0.70 μm or less. preferable.

In the method for manufacturing a display device of the present invention, it is preferable that a machining allowance on the chamfered surface of the cover glass is 3 to 35% of the thickness of the cover glass.

The touch panel of the present invention includes a cover glass having a first surface and a second surface opposite to the first surface, and a touch sensor formed on the first surface of the cover glass. The cover glass is a chemically strengthened glass, the cover glass has a surface compressive stress of 600 to 900 MPa, and a compressive stress layer depth of 5 to 20 μm. It has a clean cut surface substantially perpendicular to the first surface, and a chamfered surface formed at an edge of the second surface.

In the touch panel of the present invention, the cover glass preferably has a thickness of 0.3 to 3 mm.

In the touch panel of the present invention, the cover glass has two types of stress patterns, a stress distribution pattern A on the glass surface side and a stress distribution pattern B on the glass inner side, in the compressive stress layer. in the case of approximating the the stress pattern B respectively a linear function, when the inclination of the stress pattern a and S _a, the slope of the stress pattern B and S _B, satisfy the relationship of S _a> S _B, and, The interference fringes of the cover glass are observed using a surface stress meter whose observation principle is the optical waveguide effect. The distance between the _first interference fringe and the second interference fringe from the glass surface is r ₁ , and the second interference fringe is second from the glass surface. interval r ₂ between the interference fringes and the third interference _fringes, when the distance between the third interference fringes and fourth interference fringes from the glass surface was r _3, r 2 _/ r ₁ and r _{3 /} r at least one of the ₂ Preferably satisfies 0.3 to 0.7.

In the touch panel of the present invention, it is preferable that the arithmetic average roughness Ra of the clean cut surface of the cover glass is 0.07 μm or less and the maximum height roughness Rz is 0.70 μm or less.

In the touch panel of the present invention, it is preferable that the machining allowance on the chamfered surface of the cover glass is 3 to 35% of the thickness of the cover glass.

The touch panel of this invention has the same structure as the touch panel which comprises the display apparatus of this invention. Therefore, in order to exhibit the same effect as that described in the display device of the present invention, detailed description thereof is omitted.

The method for producing a touch panel of the present invention includes a step of preparing a glass plate that is chemically strengthened and has a surface compressive stress of 600 to 900 MPa and a compressive stress layer depth of 5 to 20 μm, and the glass Forming a touch sensor in at least a first region and a second region on the first surface of the plate, respectively, dividing the first region and the second region, and the glass plate By cutting the glass plate so that a clean cut surface substantially perpendicular to the first surface is formed, at least two cover glasses having the touch sensor formed on the first surface are produced. And a step of chamfering the edge of the second surface opposite to the first surface of the cover glass.

In the touch panel manufacturing method of the present invention, the cover glass preferably has a thickness of 0.3 to 3 mm.

In the touch panel manufacturing method of the present invention, the cover glass has two types of stress patterns, a stress distribution pattern A on the glass surface side and a stress distribution pattern B on the glass inner side, in the compressive stress layer. in the case of approximating the pattern a and the stress pattern B respectively a linear function, when the inclination of the stress pattern a and S _a, the slope of the stress pattern B and S _B, satisfy the relationship of S _a> S _B In addition, the interference fringes of the cover glass are observed using a surface stress meter whose observation principle is the optical waveguide effect, the distance between the _first interference fringes and the second interference fringes from the glass surface is r ₁ , and the glass surface when the distance between the second interference pattern and third interference fringes r _2, the distance between the third interference fringes and fourth interference fringes from the glass surface was r ₃ from, r 2 _/ r ₁ and r of ₃ / _{r 2} small Both one but preferably satisfies 0.3 to 0.7.

In the touch panel manufacturing method of the present invention, the arithmetic mean roughness Ra of the clean cut surface of the cover glass is preferably 0.07 μm or less, and the maximum height roughness Rz is preferably 0.70 μm or less. .

In the touch panel manufacturing method of the present invention, it is preferable that a machining allowance of the cover glass on the chamfered surface is 3 to 35% of the thickness of the cover glass.

In the touch panel manufacturing method of the present invention, the touch panel is manufactured by the same process as the display device manufacturing method of the present invention. Accordingly, the same effect as that described in the method for manufacturing the display device of the present invention is exhibited, and thus detailed description thereof is omitted.

According to the present invention, in the cover glass on which the touch sensor is formed, a display device including the cover glass having high end surface strength on the surface on the touch sensor side and high safety on the outermost surface on the viewing side can be provided. .

FIG. 1 is a cross-sectional view schematically showing an example of a display device according to an embodiment of the present invention. FIG. 2 is a perspective view schematically showing an example of a cover glass constituting the display device according to the embodiment of the present invention. FIG. 3A and FIG. 3B are enlarged cross-sectional views schematically showing the shape of the chamfered surface of the cover glass constituting the display device according to the embodiment of the present invention. FIG. 4 is a graph schematically showing the relationship between the inclination of the stress pattern and the integrated value of the compressive stress in the compressive stress layer. FIGS. 5A to 5C are graphs schematically showing the relationship between the interference fringe spacing and the stress pattern inclination. FIG. 6 is a diagram schematically illustrating an example of interference fringes in the field of view of the surface stress meter. FIG. 7A and FIG. 7B are diagrams for explaining an example of the principle of position detection in a capacitive touch panel. 8 (a) to 8 (f) are cross-sectional views schematically showing an example of the method for manufacturing the display device according to the embodiment of the present invention. FIGS. 9A to 9E are diagrams for explaining an example of a processing principle by laser scribing.

Hereinafter, embodiments of the present invention will be specifically described. However, the present invention is not limited to the following embodiments, and can be applied with appropriate modifications without departing from the scope of the present invention.

First, a display device according to an embodiment of the present invention will be described. In addition, the touch panel provided with the cover glass which is a component of the display apparatus demonstrated below and the touch sensor formed on the 1st surface of the said cover glass is also embodiment of this invention.

FIG. 1 is a cross-sectional view schematically showing an example of a display device according to an embodiment of the present invention.
The display device 10 illustrated in FIG. 1 includes a touch panel 100 and a display panel 200, and the touch panel 100 includes a cover glass 110 and a touch sensor 120.

The touch panel 100 is attached to the front surface (viewing side surface) of the display panel 200. That is, the back surface (surface on the anti-viewing side) of the touch panel 100 is disposed to face the front surface of the display panel 200.

The cover glass 110 has a first surface 111 that is the surface on the anti-viewing side and a second surface 112 that is the surface on the viewing side, and is a clean surface that is substantially perpendicular to the first surface 111. A cut surface 113 and a chamfered surface 114 formed at the edge of the second surface 112 are provided. Further, the first surface 111 of the cover glass 110 is disposed to face the front surface of the display panel 200. The cover glass 110 will be described later in detail.

The touch sensor 120 is formed on the first surface 111 of the cover glass 110, and the surface on the non-viewing side of the touch sensor 120 is disposed to face the front surface of the display panel 200.

Therefore, in the display device 10 shown in FIG. 1, the cover glass 110, the touch sensor 120, and the display panel 200 are arranged in this order from the viewing side. The cover glass 110 is disposed on the outermost side on the viewing side.

The cover glass constituting the display device according to the embodiment of the present invention is a single cover glass by using the cover glass as a substrate for touch sensor formation, which is called “One Glass Solution” or “cover glass integrated type”. It is responsible for the cover function and the board function.

FIG. 2 is a perspective view schematically showing an example of a cover glass constituting the display device according to the embodiment of the present invention.
As described above, the cover glass 110 has the first surface 111 and the second surface 112 opposite to the first surface 111. The cover glass 110 has a clean cut surface 113 substantially perpendicular to the first surface 111 and a chamfered surface 114 formed at the edge of the second surface 112.

The clean cut surface 113 is a surface free from chipping or microcracks, and is preferably a mirror surface. Such a clean cut surface 113 can be obtained by applying mechanical scribe to the second surface 112 and breaking it, and is also cut by laser scribe from the first surface 111 or the second surface 112 side. Can also be obtained. The clean cut surface 113 is preferably a cut surface by laser scribing, and more preferably a cut surface by laser scribing from the first surface 111 side.

The clean cut surface 113 is substantially perpendicular to the first surface 111.
In the present specification, “substantially vertical” includes not only completely vertical but also what can be substantially regarded as vertical in view of the effects of the present invention.

In the cover glass constituting the display device according to the embodiment of the present invention, as long as the clean cut surface is substantially perpendicular to the first surface, etching is performed with an etchant made of hydrofluoric acid or buffered hydrofluoric acid. May be.

In the cover glass constituting the display device according to the embodiment of the present invention, the arithmetic average roughness Ra of the clean cut surface (end surface) is preferably 0.07 μm or less, more preferably 0.06 μm or less, and still more preferably 0.8. It is 05 μm or less. Further, the maximum height roughness Rz of the clean cut surface (end surface) is preferably 0.70 μm or less, more preferably 0.60 μm, and further preferably 0.50 μm or less. The lower limit of Ra is preferably as small as possible, but is not particularly set, and may be 0.005 μm. The lower limit of Rz is preferably as small as possible, but is not particularly set, and may be 0.010 μm. Ra is an arithmetic average roughness defined by JIS B 0601: 2001, and Rz is a maximum height roughness defined by JIS B 0601: 2001.

In the display device according to the embodiment of the present invention, the clean cut surface only needs to be formed continuously with the first surface of the cover glass, and is more preferably formed continuously with the chamfered surface. preferable. The clean cut surface is preferably formed continuously with all the first surfaces of the cover glass.

The chamfered surface 114 can be obtained by chamfering the edge of the second surface 112. The chamfering is to make a surface by cutting off the corners, and the processing method is selected from a method combining one or more of C chamfering and R chamfering by machining. Further, it is preferably finished in a mirror state with an abrasive such as cerium oxide. Alternatively, the chamfering may be performed by immersing in an etching solution made of hydrofluoric acid or buffered hydrofluoric acid. Furthermore, chamfering may be performed by combining the above-described machining and immersion in an etching solution.

FIG. 3A and FIG. 3B are enlarged cross-sectional views schematically showing the shape of the chamfered surface of the cover glass constituting the display device according to the embodiment of the present invention.
FIG. 3A shows chamfering in which the shape of the corner is cut off by one plane, and such chamfering is referred to as C chamfering. FIG. 3B shows chamfering in which the shape of the corner is curved, and such chamfering is referred to as R chamfering. In FIGS. 3A and 3B, the length indicated by the double arrow x is the same on the surface side and the end surface side, but this length may be different on the surface side and the end surface side.

In the display device according to the embodiment of the present invention, as long as safety can be ensured without causing a hand or finger cut or the like, the machining allowance (chamfering range) on the chamfered surface of the cover glass may be appropriately determined. For example, when the shape of the chamfered surface is C chamfering or R chamfering, the machining allowance from the top A (the length indicated by the double arrow x in FIGS. 3A and 3B) is the thickness of the cover glass. It is preferably 3 to 35% of the above. Even when the shape of the chamfered surface is other than C chamfering or R chamfering, the machining allowance from the top A is preferably 3 to 35% of the thickness of the cover glass. If the machining allowance is less than 3% with respect to the thickness of the cover glass, the scribe marks cannot be removed. On the other hand, if the allowance is larger than 35% with respect to the thickness of the cover glass, the allowance becomes too large with respect to the thickness of the cover glass, which is not preferable in appearance.

In the display device according to the embodiment of the present invention, the chamfered surface is preferably formed on all edges of the second surface of the cover glass, but the chamfered surface is formed on the edge of the second surface. There may be a portion that is not formed.

The cover glass constituting the display device according to the embodiment of the present invention is a chemically strengthened glass (chemically strengthened glass). For example, sodium ions in the glass surface layer are ion-exchanged with potassium ions existing outside the glass, so that a compressive stress layer is formed on the glass surface.

The surface compressive stress of the cover glass constituting the display device according to the embodiment of the present invention is 600 to 900 MPa. Considering the resistance to glass impact or scratches, the lower limit of the surface compressive stress may be 620 MPa, or even 650 MPa. A higher surface compressive stress value is preferred, but considering that the internal tensile stress increases as the surface compressive stress value increases, the upper limit of the surface compressive stress is 850 MPa, further 800 MPa, or even 750 MPa. It may be.

The compressive stress layer depth of the cover glass constituting the display device according to the embodiment of the present invention is 5 to 20 μm, preferably 6 to 15 μm, considering the scratch resistance and cutting workability at the same time. The thickness is preferably 9 to 15 μm, more preferably 10 to 13 μm.

In the present specification, the surface compressive stress after ion exchange and the compressive stress layer depth are values measured by a photoelastic method using a surface stress meter utilizing the optical waveguide effect. In the measurement using a surface stress meter, a refractive index and a photoelastic constant corresponding to the glass composition of the glass before ion exchange must be used.

In the cover glass constituting the display device according to the embodiment of the present invention, it is desirable that the glass plate be as thin as possible in order to reduce the weight of the final product such as a mobile device and ensure the device capacity of the battery or the like. If it is too large, the stress generated by the glass bending will increase. On the other hand, if the plate thickness is too thick, the apparatus weight increases and the visibility of the display device decreases. Therefore, the upper limit of the thickness of the cover glass is preferably 3 mm, more preferably 2 mm. Further, the lower limit of the thickness of the cover glass is preferably 0.3 mm, more preferably 0.4 mm.

Although the shape of the cover glass which comprises the display apparatus which concerns on embodiment of this invention is not specifically limited, It is preferable that it is a plate-shaped object. Further, when the shape of the cover glass is a plate-like body, it may be a flat plate or a bent plate, and includes various shapes. Moreover, in flat form, it may be a rectangle or a disk shape, and may be processed into the design shape by which partial drilling process or R process etc. were given to the corner part.

Even if the surface of the cover glass in the display device according to the embodiment of the present invention is provided with anti-fingerprint property, anti-glare property, and function by surface coating by drug application, fine processing, film sticking, or the like. Good. Moreover, the print according to the color tone of the display panel may be given to the surface of the cover glass, and the partial drilling process etc. may be given.
For example, the cover glass may be provided with a film having a low reflection function and an antiglare function, a film having a fingerprint adhesion preventing function, and a polarizer film for improving contrast. The film having these functions may be provided by attaching a plastic film or the like having the above functions to a cover glass, or may be provided by means such as coating or vapor deposition.
Regarding the shape and size of the cover glass, not only a simple rectangle but also various shapes and sizes corresponding to the design shape of the display panel, such as a shape in which a corner portion is processed into a circle or the like, can be considered.

As described above, the cover glass in the display device according to the embodiment of the present invention is a chemically tempered glass. Such a chemically tempered glass contains the alkali metal ions A most contained in the glass on the glass surface. , And can be prepared by ion exchange replacing alkali metal ions B having an ionic radius larger than that of the alkali metal ions A.

For example, when the alkali metal ion A is a sodium ion (Na ⁺ ion), as the alkali metal ion B, potassium ion (K ⁺ ion), rubidium ion (Rb ⁺ ion), and cesium ion (Cs ⁺ ion) At least one can be used. When the alkali metal ion A is a sodium ion, it is preferable to use a potassium ion as the alkali metal ion B.

For ion exchange, one or more of nitrates, sulfates, carbonates, hydroxides and phosphates containing at least alkali metal ions B can be used. And when the alkali metal ion A is a sodium ion, it is preferable to use a nitrate containing at least a potassium ion.

In the cover glass constituting the display device according to the embodiment of the present invention, the glass before ion exchange contains soda-lime glass, aluminosilicate glass, and borosilicate glass as long as it contains alkali metal ions that can be ion-exchanged. Although not particularly limited, it is preferably a soda lime glass, and substantially by mass, SiO ₂ : 65 to 75%, Na ₂ O + K ₂ O: 5 to 20%, CaO: 2 to 15%, MgO : 0 to 10%, Al ₂ O ₃ : 0 to 5% is more preferable.

As chemically strengthened glass that can be used as a cover glass, for example, Patent Document 1 and Patent Document 2 disclose so-called aluminosilicate glass. When chemically strengthened aluminosilicate glass is cut by laser scribing, which will be described later, even if an initial crack for laser scribing is introduced, it is difficult to form the initial crack because of high Vickers hardness. If it is difficult to form an initial crack, it is difficult to progress the crack with a laser, and thus scribing such glass is not easy. On the other hand, with soda lime glass, laser scribing can be performed with a lower laser power than aluminosilicate glass or the like.

In this specification, “Na ₂ O + K ₂ O: 5 to 20%” means that the total content of Na ₂ O and K ₂ O in the glass is 5 to 20% by mass.

SiO ₂ is a main component of glass. If it is less than 65%, the strength is lowered and the chemical durability of the glass is deteriorated. On the other hand, if it exceeds 75%, the high-temperature viscosity of the glass melt becomes high, and glass molding becomes difficult. Accordingly, the range is preferably 65 to 75%, more preferably 68 to 73%.

Na ₂ O is indispensable for chemical strengthening treatment and is an essential component. If it is less than 5%, ion exchange is insufficient, and the strength after the chemical strengthening treatment is not improved so much. On the other hand, if it exceeds 20%, the chemical durability of the glass is deteriorated and the weather resistance is deteriorated. Therefore, the range is preferably 5 to 20%, more preferably 5 to 18%, and still more preferably 7 to 16%. Meanwhile, K 2 _O is not an essential component, and acts as a flux during melting the glass with Na 2 _O, although some additives have an effect as an auxiliary component for promoting ion exchange, the excessive addition of Na ₂ Due to the mixed alkali effect with O, the migration of sodium ions is suppressed and ion exchange becomes difficult. If it exceeds 5%, it is difficult to improve the strength by ion exchange. The range of Na ₂ O + K ₂ O is preferably 5 to 20%, more preferably 7 to 18%, and still more preferably 10 to 17%.

CaO improves the chemical durability of the glass. Moreover, since it has the effect | action which lowers | hangs the viscosity of the molten glass at the time of glass melting and improves mass productivity, it is desirable to contain 2% or more. On the other hand, if it exceeds 15%, the movement of sodium ions is suppressed. Accordingly, the range is preferably 2 to 15%, more preferably 4 to 13%, and still more preferably 5 to 11%.

Although MgO is not an essential component, it has less effect of suppressing the movement of sodium ions compared to CaO, and it is desirable to replace CaO with MgO. On the other hand, compared with CaO, the effect | action which lowers | hangs the viscosity of the molten glass at the time of glass melting is also small, and when it exceeds 10%, glass viscosity will become high and mass productivity will deteriorate. Therefore, the range is preferably 0 to 10%, more preferably 0 to 8%, and further preferably 1 to 6%.

Al ₂ O ₃ is not an essential component, but is a component that increases strength and improves ion exchange efficiency. If the mass percentage exceeds 5%, the high-temperature viscosity of the glass melt increases and the tendency to devitrification increases, making glass molding difficult. Moreover, since the ion exchange efficiency becomes excessive and the depth of the compressive stress layer becomes deep, the cutting property after chemical strengthening is deteriorated. Therefore, the range is preferably 0 to 5%, more preferably 1 to 4%, and still more preferably 1 to 3% (3 is not included).

The glass before the ion exchange is soda lime glass, and is preferably substantially composed of the above components. However, the total amount of Fe ₂ O ₃ , TiO ₂ , CeO ₂ , SO _{3 and} other trace components is 1% in total. May be contained.

The strain point of the glass before ion exchange is preferably 450 to 550 ° C., more preferably 480 to 530 ° C. If the strain point of the glass is less than 450 ° C, the heat resistance during chemical strengthening is insufficient. On the other hand, if it exceeds 550 ° C, the glass melting temperature becomes too high and the production efficiency of the glass plate deteriorates. , Resulting in increased costs.

The glass before ion exchange is formed by a general glass forming method such as a float method, a roll-out method, or a down draw method, and among these, it is preferable to be formed by a float method.
In addition, the surface of the glass before ion exchange may be in a state where it is formed by the above-described forming method, or a state in which functionality such as antiglare property is imparted by roughening the surface using hydrofluoric acid etching or the like. But you can.

In the cover glass constituting the display device according to the embodiment of the present invention, the Vickers hardness of the glass after chemical strengthening is preferably 5.0 to 6.0 GPa, more preferably 5.2 to 6.0 GPa. More preferably, it is 5.2 to 5.8 GPa. If the Vickers hardness is less than 5.0 GPa, it is inferior in scratchability, so it cannot withstand use in the market, while if it exceeds 6.0 GPa, the cutting property deteriorates.

The cover glass constituting the display device according to the embodiment of the present invention has two types of stress patterns in the compression stress layer, that is, the stress distribution pattern A on the glass surface side and the stress distribution pattern B on the glass inner side, in the case of approximating the the stress pattern a and the stress pattern B respectively a linear function, when the inclination of the stress pattern a and S _a, the slope of the stress pattern B and S _B, the relationship of S _a> S _B And the interference fringes of the cover glass are observed using a surface stress meter whose observation principle is the optical waveguide effect, and the distance between the _first interference fringes and the second interference fringes from the glass surface is r ₁ , When the distance between the second interference fringe and the third interference fringe from the glass surface is r ₂ and the distance between the third interference fringe and the fourth interference fringe from the glass surface is r ₃ , r ₂ / r ₁ and when the least of _{_r} 3 / _r ₂ One, but preferably satisfies 0.3 to 0.7.

In the above case, it is more preferable that at least r ₂ / r ₁ satisfies 0.3 to 0.7, and both r ₂ / r ₁ and r ₃ / r ₂ satisfy 0.3 to 0.7. More preferably.

It can be assumed that r ₃ / r ₂ satisfies 0.3 to 0.7 and r ₂ / r ₁ does not satisfy 0.3 to 0.7. This is because there is a slight relaxation tendency due to the effect of slow cooling during production. Even in the above case, if r ₃ / r ₂ satisfies 0.3 to 0.7, the internal tensile stress Tend to be reduced.

FIG. 4 is a graph schematically showing the relationship between the inclination of the stress pattern and the integrated value of the compressive stress in the compressive stress layer.
In FIG. 4, the graph which approximated the stress pattern in the preferable cover glass (chemically tempered glass) with the linear function is shown by the solid line.
In FIG. 4, the stress distribution pattern A on the glass surface side and the stress distribution pattern B on the glass inner side have two types of stress patterns in the compressive stress layer. The slope of the stress pattern A is S _A , the stress when the inclination of the pattern B was _{S _B,} satisfy the relationship of S a> _{S B.}
On the other hand, in FIG. 4, a graph in which the inclination of the stress pattern is constant, that is, a graph having only one type of stress pattern is indicated by a broken line.
As is clear from FIG. 4, even when the surface compressive stress value σ and the compressive stress layer depth d are the same, in the chemically strengthened glass indicated by the solid line, the integrated value of the compressive stress in the compressive stress layer. Can be reduced.

In chemically strengthened glass, the integrated value of the compressive stress in the compressive stress layer and the integrated value of the internal tensile stress in the tensile stress layer are balanced with each other.
Accordingly, it is presumed that a preferable cover glass has a low internal tensile stress while having a high surface compressive stress value.

In the present specification, the “slope of the stress pattern” means the absolute value of the slope of the compressive stress with respect to the depth from the glass surface.
Therefore, a stress pattern with a large slope is steep and a stress pattern with a small slope is gradual.
In addition, since the compressive stress in the compressive stress layer decreases from the glass surface toward the inside of the glass, the positive and negative slopes of the stress pattern A and the stress pattern B coincide.

In addition, when determining the inclination of the stress pattern, regardless of the shape of the generated stress pattern, the stress pattern approximated by the linear function from the glass surface side is A, and the stress pattern approximated by the linear function from the glass inner side is used. What is necessary is just to obtain | require each inclination as B.

Hereinafter, the relationship between the interference fringe spacing and the stress pattern inclination will be described.
FIGS. 5A to 5C are graphs schematically showing the relationship between the interference fringe spacing and the stress pattern inclination.
As shown in FIGS. 5A to 5C, it is known that the interval between the interference fringes corresponds to the inclination of the stress pattern.
That is, as shown in FIG. 5A, when the interval between the interference fringes is wide, the inclination of the stress pattern is large. On the other hand, when the interval between the interference fringes is narrow as shown in FIG. This means that the inclination of the stress pattern is small. FIG. 5C shows a stress pattern obtained by combining FIGS. 5A and 5B. When the stress pattern is approximated by two linear functions having different inclinations, it is possible to confirm the correspondence between the change in the interference fringe spacing and the change in the stress pattern inclination. Thus, by observing the interval between the interference fringes, information on the inclination of the stress pattern can be obtained.

Here, r ₂ / r ₁ is close to 1 because the distance r ₂ between the second interference fringe and the third interference fringe from the glass surface is the first interference fringe and the second interference fringe from the glass surface. it means the distance r ₁ between the same degree, as the r 2 _/ r ₁ is less than 1, the interval r ₂ is meant to be smaller than the distance r _1. The same applies to r ₃ / r ₂ .

It should be noted that ion exchange basically follows Fick's diffusion law, and the diffusion law itself is not a linear function, so strictly speaking, the stress pattern is not a straight line. More precisely with respect to the relationship between the interference fringe spacing and the stress pattern, using a sequence of interference fringe widths related by at least one of r ₂ / r ₁ and r ₃ / r ₂ than using a straight line. The accuracy of approximation is high, and it is easy for production management.

From the above, when at least one of r ₂ / r ₁ and r ₃ / r ₂ satisfies 0.3 to 0.7, the stress decreases sharply on the glass surface side, and the more toward the glass inner side, The rate at which the stress decreases is reduced. This can approximately represent the change in the inclination of the stress pattern as shown in FIG. Therefore, the relationship of S _A > S _B can be satisfied.

Hereinafter, a method for observing the interference fringes of the chemically strengthened glass plate using a surface stress meter will be described.
FIG. 6 is a diagram schematically illustrating an example of interference fringes in the field of view of the surface stress meter.
The lower side of FIG. 6 represents the glass surface side, and the upper side of FIG. 6 represents the glass inner side.

As shown in FIG. 6, the distance r ₁ between the _first interference fringe L ₁ and the second interference fringe L ₂ from the glass surface, the second interference fringe L ₂ and the third interference fringe L ₃ from the glass surface, interval _{r 2,} and measures the distance _{r 3} from the glass surface the third interference fringe _{L 3} and the fourth interference fringe _{L 4.} From the measured interval r ₁ , interval r _2, and interval r ₃ , the value of r ₂ / r _{1 and} the value of r ₃ / r ₂ are calculated.

The value of r ₂ / r ₁ or r ₃ / r ₂ calculated by the above method is preferably 0.3 to 0.7. The lower limit value of r ₂ / r ₁ or r ₃ / r ₂ is preferably 0.35, more preferably 0.4. The upper limit value of r ₂ / r ₁ or r ₃ / r ₂ is preferably 0.65, more preferably 0.63.

The touch sensor that constitutes the display device according to the embodiment of the present invention has a multilayer wiring structure of transparent electrodes, for example, in the case of a capacitive detection method. The capacitance type detection method is introduced in Japanese Patent Application Laid-Open No. 2008-80743.

FIG. 7A and FIG. 7B are diagrams for explaining an example of the principle of position detection in a capacitive touch panel. However, FIGS. 7A and 7B show a case where a one-dimensional position is detected for the sake of simplicity. When the capacitance method is used, a touch panel 150 in which a transparent conductive film 170 such as ITO (Indium Tin Oxide: indium oxide to which tin oxide is added) or the like is formed on a glass substrate 160 is used.

As shown in FIG. 7A, an in-phase AC voltage is applied to both ends of the touch panel 150 from a current source via a current detection resistor r. When a contact body such as a pen or a finger is neither in contact nor in proximity, no current flows through the touch panel 150. As shown in FIG. 7B, when the contact body 180 that is a conductor contacts or approaches the touch panel 150, a capacitor is formed between the contact body 180 and the touch panel 150, and a weak current flows through the contact body 180. Flows. Therefore, currents I ₁ and I ₂ flow from the current source. If the contact position of the contact body 180 is different, the values of the currents I ₁ and I ₂ are different. Therefore, by detecting the values of the currents I ₁ and I ₂ , the position where the contact body 180 is in contact with or close to the contact body 180 is detected. be able to. Actually, since the touch panel generally detects a two-dimensional position where a contact body comes into contact or comes close, an AC voltage is applied from four locations on the touch panel.

In addition to the capacitance method, the detection method may be a resistance detection method, an optical method, an ultrasonic method, or the like.

The touch panel constituting the display device according to the embodiment of the present invention can be manufactured by subjecting a glass plate larger than the cover glass to chemical strengthening treatment and forming a touch sensor, and then dividing the glass plate. preferable. In this case, a plurality of touch panels can be efficiently manufactured. However, the touch panel may be manufactured by cutting the glass plate first and processing it into a design shape such as a bent plate shape, and then applying a chemical strengthening treatment to form a touch sensor.

As a display panel constituting the display device according to the embodiment of the present invention, a liquid crystal display panel is usually used. However, in some cases, other display panels such as an organic EL display and a plasma display panel are used. Good.

The display device according to the embodiment of the present invention preferably has a member for integrating the cover glass and the display panel. In order to conceal the wiring provided on the peripheral side of the member and the display device, a masking layer having a width sufficient to conceal the cover glass is formed on the peripheral edge of the cover glass, preferably having an absorbance of 3 or more, more preferably 4 or more. A layer is preferably provided.

This masking layer can be formed by applying a preparation containing a thermosetting synthetic resin, a pigment, and a dye, and drying and heating. As the thermosetting synthetic resin, an epoxy resin, an acrylic silicon resin, an alkyd resin, a polyamide resin, a fluorine resin, or the like can be used.

The pigment is one or more selected from the group consisting of iron oxide, copper oxide, chromium oxide, cobalt oxide, manganese oxide, aluminum oxide, zinc oxide, lead chromate, lead sulfate, lead molybdate and the like. A mixture of materials can be used.

As the dye, dioxazine-based, phthalocyanine-based, anthraquinone-based organic substances, and the like can be used.

Solvents such as diethylene glycol monobutyl ether acetate and ethylene glycol monobutyl ether can be used as a medium for making this mixture into a paste for coating. Further, a modified aliphatic polyamine resin, N-butanol or the like may be mixed as a curing reaction accelerator.

The thickness of the masking layer is preferably 35 μm or less, and more preferably 30 μm or less. When the thickness of the masking layer is larger than 35 μm, the step at the boundary between the masking layer surface and the glass substrate surface becomes large, and when the film as described above is provided, bubbles easily remain in the step portion.

Hereinafter, a method for manufacturing a display device according to an embodiment of the present invention will be described. In addition, the manufacturing method of the touch panel which is a part of the manufacturing method of the display apparatus demonstrated below is also embodiment of this invention.

8 (a) to 8 (f) are cross-sectional views schematically showing an example of the method for manufacturing the display device according to the embodiment of the present invention.

In the step shown in FIG. 8A, a glass plate 310 is prepared.
The glass plate to be prepared is a chemically strengthened glass plate having a surface compressive stress of 600 to 900 MPa and a compressive stress layer depth of 5 to 20 μm.

When producing the said glass plate, the method is not specifically limited, Alkali metal ion A with respect to the sum total of the molar amount of alkali metal ion A and the molar amount of alkali metal ion B including alkali metal ion A and alkali metal ion B A first step of contacting the glass plate with a first salt having a molar amount ratio P (mol%), and a first ratio Q (mol%) smaller than the ratio P after the first step. And a second step of bringing a glass plate into contact with the salt of 2 (hereinafter referred to as a first chemical strengthening method).
Moreover, as a method for producing the glass plate, the glass plate is brought into contact with a first salt containing alkali metal ions A, and the first salt is an alkali with respect to the total molar amount of alkali metal ions. A glass plate is brought into contact with the second salt containing alkali metal ions B after the first step having a molar amount ratio X (mol%) of metal ions A = 90 to 100 mol% and the first step. The second salt is a step wherein the ratio Y (mol%) of the molar amount of alkali metal ions A to the total molar amount of alkali metal ions Y (mol%) = 0 to 10 mol%; After the step 2, the glass plate is brought into contact with a third salt containing alkali metal ions B, and the third salt is a mole of alkali metal ions B with respect to the total molar amount of alkali metal ions. Method comprising a third step of having the ratio Z (mol%) = 98 ~ 100mol% (hereinafter, referred to as the second chemical strengthening process) it is also preferable.

The glass plate before chemical strengthening (ion exchange) and the glass plate after chemical strengthening (ion exchange) have the same structure as the glass described in the cover glass constituting the display device according to the above-described embodiment of the present invention. Detailed description thereof will be omitted.

First, the first chemical strengthening method will be described.
In the first chemical strengthening method, the glass surface layer is made to have alkali metal ions A and alkali metal ions B (preferably sodium ions and potassium ions) during the first step by adopting the first salt structure as described above. Ions) are included. As a result, the effect of preventing the relaxation phenomenon of the compressive stress generated in the second step is brought about. That is, the surface compressive stress generated by the ion exchange in the second step remains even if slightly relaxed because the first step is performed. Therefore, a large surface compressive stress can be obtained.

In the first step and the second step, “contacting a glass plate with salt” means contacting or immersing the glass plate in a salt bath. Thus, in this specification, “contact” is a concept including “immersion”. The same applies to the second chemical strengthening method.

Further, the contact form of the salt may be a form in which the paste-like salt is in direct contact, a form in which it is sprayed as an aqueous solution, a form in which the salt is immersed in a molten salt heated to a melting point or higher, etc. Of these, it is desirable to immerse in molten salt.

Specific examples of the alkali metal ion A and the alkali metal ion B are as described above, but are preferably a sodium ion and a potassium ion, respectively.

Moreover, as a kind of salt, the 1 type (s) or 2 or more types of mixture can be used among nitrate, sulfate, carbonate, hydroxide salt, and phosphate.
As the salt containing the alkali metal ion A, it is preferable to use a sodium nitrate molten salt, and as the salt containing the alkali metal ion B, it is preferable to use a potassium nitrate molten salt. Therefore, as the salt containing the alkali metal ion A and the alkali metal ion B, it is preferable to use a mixed molten salt composed of sodium nitrate and potassium nitrate.

The depth of the compressive stress layer formed after the first step is preferably 5 to 23 μm. Further, it is more preferably 7 to 20 μm, and further preferably 10 to 18 μm. In the first step, it is preferable to adjust the temperature of the first salt and the time of contact with the first salt in the first step so as to be the depth of the compressive stress layer.

In the second step, the temperature of the second salt and the second salt are adjusted according to the ratio Q so that the depth of the compressive stress layer formed after the second step is 5 to 20 μm. It is preferable to adjust the contact time.

Here, if the ratio P of the first salt is too large, the composition of the surface layer of the glass plate is difficult to be modified, and the surface of the glass plate tends to become cloudy, which hinders the improvement of the reliability of the glass strength. End up. On the other hand, if the ratio P of the first salt is too small, the composition of the surface layer of the glass plate tends to be modified in the first step, and most of the alkali metal ions A in the glass are alkaline. It is ion-exchanged with the metal ion B. For this reason, ion exchange does not proceed in the second step, and the desired surface compressive stress and strength at a fracture probability of 1% cannot be obtained. On the other hand, if the ratio P is too small, the compressive stress layer tends to be deeper after the first step, which affects the cutability of the glass. Therefore, the ratio P is preferably 5 to 50 mol%. The lower limit of the ratio P is more preferably 15 mol%, still more preferably 20 mol%. The upper limit of the ratio P is more preferably 40 mol%, still more preferably 35 mol%.

If the ratio Q of the second salt is too large, a sufficient amount of alkali metal ions B is not introduced into the surface layer of the glass plate in the second step, and re-diffusion driving of the alkali metal ions B is performed. The force also tends to be weakened, making it difficult to obtain a desired surface compressive stress. Therefore, the ratio Q is preferably 0 to 10 mol%. The lower limit of the ratio Q is more preferably 2 mol%, still more preferably 1 mol%. Thus, the second salt may be substantially free of alkali metal ions A (for example, sodium ions) and may include only alkali metal ions B (for example, potassium ions) as cations.

In addition, although the structure of the 1st salt and the 2nd salt was limited and demonstrated to the alkali metal ion A and the alkali metal ion B, unless the objective of this invention was impaired, the stable metal which does not raise | generate reaction with a salt It does not prevent the presence of oxides, impurities or other salts. For example, silver ions or copper ions may be contained in the first salt or the second salt.

In addition, if the treatment temperature in the first step (the temperature of the first salt) is too high, the surface of the glass plate is likely to become clouded and not only cannot improve the reliability of the glass strength, Since the compressive stress layer also becomes deep, the glass cutting property is affected. In addition, the relaxation of the compressive stress generated during the first step tends to progress. On the other hand, if the temperature of the first salt is too low, ion exchange in the first step is not promoted, and a desired compressive stress layer depth cannot be obtained. Therefore, the temperature of the first salt is preferably 400 to 530 ° C. The lower limit of the temperature of the first salt is more preferably 410 ° C, and further preferably 430 ° C. The upper limit of the temperature of the first salt is more preferably 515 ° C., further preferably 500 ° C., and particularly preferably 485 ° C.

Further, if the treatment temperature in the second step (the temperature of the second salt) is too high, not only will the relaxation of the compressive stress generated in the first step occur during the second step, but also the compressive stress. Since the layer also becomes deep, the glass cutting property is affected. On the other hand, if the temperature of the second salt is too low, ion exchange in the second step is not promoted, and not only high surface compressive stress cannot be generated during the second step, but also alkali metal ions B Since re-diffusion does not easily occur, a desired compressive stress layer depth cannot be obtained. Therefore, the temperature of the second salt is preferably equal to or lower than the temperature of the first salt, and more preferably lower than the temperature of the first salt. The temperature of the second salt is preferably 380 to 500 ° C. The lower limit of the temperature of the second salt is more preferably 390 ° C., further preferably 400 ° C., and particularly preferably 410 ° C. The upper limit of the temperature of the second salt is more preferably 490 ° C., further preferably 480 ° C., and particularly preferably 460 ° C.

The total time for contacting the glass plate with the first salt in the first step and the time for contacting the glass plate with the second salt in the second step is preferably 1 to 12 hours, More preferably, it is 2 to 6 hours.

Specifically, if the time for bringing the glass plate into contact with the first salt is too long, the compressive stress generated in the first step is easily relaxed. Furthermore, the depth of the compressive stress layer tends to increase. This affects the cutability of the glass. On the other hand, if the time for bringing the glass plate into contact with the first salt is too short, the effect of modifying the glass surface layer cannot be sufficiently obtained in the first step, and stress relaxation tends to occur in the second step. turn into.
Therefore, the time for bringing the glass plate into contact with the first salt in the first step is preferably 0.5 to 8 hours, more preferably 1 to 6 hours, and further preferably 1 to 4 hours.

In the second step, it is desirable to prevent the relaxation of the stress generated by the ion exchange treatment as much as possible. However, the longer the time for which the glass plate is brought into contact with the salt, the longer the stress relaxation. Also, the depth of the compressive stress layer after the second step tends to be deep, which also affects the cutability of the glass. On the other hand, even if the time for bringing the glass plate into contact with the second salt is too short, ion exchange between the alkali metal ions A and the alkali metal ions B does not proceed sufficiently, and it becomes difficult to generate a desired compressive stress. End up.
Therefore, the time for bringing the glass plate into contact with the second salt in the second step is preferably 0.5 to 8 hours, more preferably 0.5 to 6 hours, and further preferably 0.5 to 3 hours. .

The processing temperature and contact time of the first step and the processing temperature and contact time of the second step have been described above. These are the ion exchange amounts (chemical strengthening) in the first step and the second step. Defined as an amount obtained by dividing the absolute value of the mass difference between the front and rear glass plates by the surface area of the glass plate). That is, if the respective ion exchange amounts in the first step and the second step are approximately the same, the treatment temperature range and the contact time range described here are not limited and can be freely changed. Also good.

Next, the second chemical strengthening method will be described.
In the second chemical strengthening method, the ratio of alkali metal ions A in the surface layer of the glass plate can be increased by the first step, and finally obtained through the subsequent second step and third step. The surface compressive stress of such chemically tempered glass can be increased. In the second step, the second salt bath is diluted by alkali metal ions A flowing out of the glass plate, but the ratio (ratio Y) of alkali metal ions A in the second salt bath is 0 to 10 mol%. The range. Certainly, when the ratio of the alkali metal ions A in the second salt bath is increased, that is, the ratio of the alkali metal ions B is decreased, the value of the surface compressive stress after the second step is decreased. However, if the ratio Y is in the range of 0 to 10 mol%, the third step is performed using the third salt bath containing a large amount of alkali metal ions B, so that chemical strengthening finally having a high surface compressive stress is achieved. Glass can be produced. Furthermore, since most of the ion exchange is completed in the second step, the alkali metal ions A hardly flow out of the glass in the third step. Therefore, dilution of the third salt bath used in the third step can be prevented. Therefore, the ratio (ratio Z) of the alkali metal ions B in the third salt bath can be maintained at a high value.

Thus, in the second chemical strengthening method, chemically strengthened glass having a high surface compressive stress can be continuously produced without frequently replacing the salt bath used for ion exchange. Therefore, by performing all of the first to third steps, chemically strengthened glass having a high surface compressive stress value can be continuously produced.

Specific examples of the alkali metal ion A and the alkali metal ion B are as described above, but are preferably a sodium ion and a potassium ion, respectively.
Moreover, as a kind of salt, the 1 type (s) or 2 or more types of mixture can be used among nitrate, sulfate, carbonate, hydroxide salt, and phosphate. Of these, nitrates are preferred.

In the first salt, the ratio X (mol%) of the molar amount of alkali metal ions A to the total molar amount of alkali metal ions is 90 to 100 mol%, preferably 95 to 100 mol%, more preferably. 98 to 100 mol%. The ratio X of the first salt is 100 mol%, that is, the first salt contains substantially no other alkali metal ions and contains only alkali metal ions A (for example, sodium ions) as cations. Preferably it is.

If the ratio X of the first salt is too small, it is difficult to obtain the effect of increasing the ratio of alkali metal ions A in the surface layer of the glass plate, and the desired surface can be obtained even if the second and third steps are performed. Chemically tempered glass with compressive stress cannot be produced.

The salt temperature (first salt temperature) in the first step is preferably 375 to 520 ° C. The lower limit of the temperature of the first salt is more preferably 385 ° C, and further preferably 400 ° C. The upper limit of the temperature of the first salt is more preferably 510 ° C, and further preferably 500 ° C.
If the temperature of the first salt is too high, the glass surface is likely to become cloudy. On the other hand, if the temperature of the first salt is too low, the glass surface modification effect in the first step cannot be sufficiently obtained.

The time for bringing the glass plate into contact with the first salt in the first step is preferably 0.5 to 10 hours, more preferably 1 to 7 hours. If the time for bringing the glass plate into contact with the first salt is too long, the time required for producing the chemically strengthened glass becomes too long. On the other hand, if the time for bringing the glass plate into contact with the first salt is too short, the effect of modifying the glass surface layer in the first step cannot be sufficiently obtained.

In the second step, when a mixture of nitrate and hydroxide salt is used, the compressive stress generated in the second step can be increased as compared with the case of only nitrate. However, only in the second step, white turbidity is likely to occur on the surface of the glass plate when stored in the atmosphere. However, by performing a third step described later after the second step, generation of white turbidity can be prevented and a high surface stress can be obtained. The hydroxide salt to be mixed with the nitrate is preferably 0 to 1500 ppm, more preferably 0 to 1000 ppm with respect to 100 mol% of the nitrate.

In the second salt, the ratio Y (mol%) of the molar amount of alkali metal ions A to the total molar amount of alkali metal ions is 0 to 10 mol%, preferably 0 to 5 mol%, more preferably 0 to 1 mol%. The ratio Y of the second salt is preferably 0 mol%, and the second salt substantially does not contain the alkali metal ion A and contains only the alkali metal ion B (for example, potassium ion) as the cation. It is more preferable.

When the ratio Y of the second salt is larger than 10 mol%, a sufficient amount of alkali metal ions B is not introduced into the glass surface layer in the second step, and the desired surface compression is achieved even if the third step is performed later. Chemically strengthened glass having stress cannot be produced.

In addition, although it is preferable that a 2nd salt is an unused salt containing only the alkali metal ion B, the used salt diluted with the alkali metal ion A may be sufficient.

In the second step, the ratio of the second salt is such that the depth of the compressive stress layer formed after the second step is 3 to 25 μm (more preferably 5 to 20 μm, still more preferably 5 to 18 μm). It is preferable to adjust the treatment temperature (the temperature of the second salt) according to Y.

If the treatment temperature in the second step (the temperature of the second salt) is too high, the glass surface is more likely to become cloudy and the compressive stress layer also becomes deep, which affects the glass cutting property. Will be given. On the other hand, if the temperature of the second salt is too low, ion exchange in the second step is not promoted, and the desired depth of the compressive stress layer cannot be obtained.
Therefore, the temperature of the second salt is preferably 380 to 500 ° C. The lower limit of the temperature of the second salt is more preferably 390 ° C, and further preferably 400 ° C. The upper limit of the temperature of the second salt is more preferably 490 ° C, and further preferably 480 ° C.

The time for bringing the glass plate into contact with the second salt in the second step is preferably 1 to 6 hours, more preferably 1 to 4 hours. If the time for bringing the glass plate into contact with the second salt is too long, the compressive stress generated in the second step is easily relaxed. Furthermore, the depth of the compressive stress layer tends to increase. This affects the cutability of the glass. On the other hand, if the time for bringing the glass plate into contact with the second salt is too short, ion exchange in the second step is not promoted, and the desired depth of the compressive stress layer cannot be obtained.

In the third salt, the ratio Z (mol%) of the molar amount of alkali metal ions B to the total molar amount of alkali metal ions is 98 to 100 mol%, preferably 99 to 100 mol%, more preferably. 99.3 to 100 mol%. The ratio Z of the third salt is 100 mol%, that is, the third salt is substantially free of other alkali metal ions and contains only alkali metal ions B (for example, potassium ions) as cations. Preferably it is.

If the ratio Z of the third salt is too small, a sufficient amount of alkali metal ions B are not introduced into the glass surface layer in the third step, and a chemically strengthened glass having a desired surface compressive stress cannot be produced. .

The third salt is preferably an unused salt containing only alkali metal ions B, but may be an already used salt diluted with alkali metal ions A or the like.

In the third step, the ratio of the third salt so that the depth of the compressive stress layer formed after the third step is 5 to 25 μm (more preferably 7 to 20 μm, still more preferably 8 to 18 μm). It is preferable to adjust the treatment temperature (the temperature of the third salt) according to Z.

If the treatment temperature in the third step (the temperature of the third salt) is too high, not only will the compression stress generated in the second step be relaxed in the third step, but also the compression stress layer will be deep. Since it will become, it will affect the glass cutting property. On the other hand, if the temperature of the third salt is too low, ion exchange in the third step is not promoted, and not only a high surface compressive stress cannot be generated during the third step, but also a desired compressive stress layer. Can not get the depth of.
Therefore, the temperature of the third salt is preferably 380 to 500 ° C. The lower limit of the temperature of the third salt is more preferably 390 ° C, and further preferably 400 ° C. The upper limit of the temperature of the third salt is more preferably 480 ° C, and further preferably 470 ° C.

The time for bringing the glass plate into contact with the third salt in the third step is preferably 0.5 to 4 hours, more preferably 0.5 to 3 hours. In the third step, it is desirable to prevent the relaxation of the stress generated by the ion exchange treatment as much as possible, but the stress relaxation proceeds as the time for bringing the glass plate into contact with the salt is longer. Also, the depth of the compressive stress layer after the third step tends to be deep, which also affects the cutability of the glass. On the other hand, even if the time for bringing the glass plate into contact with the third salt is too short, the ion exchange between the alkali metal ions A and the alkali metal ions B does not proceed sufficiently, and it becomes difficult to generate a desired compressive stress. End up.

Note that the treatment temperature and contact time of the first step, the treatment temperature and contact time of the second step, and the treatment temperature and contact time of the third step have been described above. The absolute value of the difference in mass of the glass plate before and after strengthening is divided by the surface area of the glass plate). That is, as long as the ion exchange amount in each step is approximately the same, the treatment temperature range and the contact time range described here are not limited and may be freely changed.

Moreover, although the structure of the 1st salt, the 2nd salt, and the 3rd salt was limited and demonstrated to the alkali metal ion A and the alkali metal ion B, unless the objective of this invention was impaired, reaction was caused with the salt. It does not prevent the presence of no stable metal oxides, impurities or other salts. For example, silver ions or copper ions may be contained in the first salt, the second salt, or the third salt.

In the step shown in FIG. 8B, a plurality of touch sensors 120 are formed on the first surface 311 of the prepared glass plate 310.
In the embodiment of the present invention, the first surface of the glass plate is divided into a plurality of regions, and a touch sensor is formed in each region. As will be described later, a plurality of touch panels (cover glass on which touch sensors are formed) can be produced by cutting the glass plate for each region. FIG. 8B shows an example in which the touch sensor 120 is formed in two regions, but the number of touch sensors to be formed depends on the size of the glass plate to be prepared first and the size of the touch panel to be prepared. Needless to say, it may be changed as appropriate.

A method for forming the touch sensor is not particularly limited, and a known method introduced in JP 2012-88946 A can be used. For example, in Japanese Unexamined Patent Application Publication No. 2012-88946, in the case of a capacitive detection method, a structure including predetermined electrode wiring is formed by a photolithography method so as to have a multilayer wiring structure of transparent electrodes. A method is disclosed.

In the steps shown in FIGS. 8C and 8D, the region where the touch sensor 120 is formed is divided, and a clean cut surface that is substantially perpendicular to the first surface 311 of the glass plate 310 is formed. As described above, the glass plate 310 on which the touch sensor 120 is formed is cut.

Specifically, as shown in FIG. 8C, scribe lines 315 are formed by laser scribing on the first surface 311 of the glass plate 310 on which the touch sensor 120 is formed. In FIG. 8C, the scribe lines 315 are formed so as to divide two regions where the touch sensor 120 is formed, but the scribe lines may be formed according to the number of touch panels to be manufactured. Laser scribe will be described in detail later.
Next, the glass plate 310 is divided along the scribe line 315 to obtain two glass plates 310 ′ as shown in FIG. As described later, the glass plate may be divided mechanically or may be divided by irradiating a laser beam on a scribe line.

Thereafter, as shown in FIG. 8E, the edge of the second surface 112 of the cover glass 110 is chamfered to form the touch sensor 120 on the first surface 111 of the cover glass 110. The touch panel 100 can be manufactured.
The cover glass 110 constituting the touch panel 100 has a clean cut surface 113 that is substantially perpendicular to the first surface 111 and a chamfered surface 114 that is formed at the edge of the second surface 112.
Since the chamfering method is as described above, the detailed description thereof is omitted.

In the step shown in FIG. 8F, the first surface 111 of the cover glass 110 is disposed so as to face the front surface of the display panel 200. Thereby, the display apparatus 10 provided with the display panel 200 and the touch panel 100 attached to the front surface of the display panel 200 is completed.

In the method shown in FIGS. 8A to 8F, the surface of the glass plate 310 that forms the touch sensor 120 and the surface of the glass plate 310 that forms the scribe line 315 are both the first surface 311. . Thereby, when conveying the glass plate 310 using conveyance means, such as a roll, it can prevent that the touch sensor 120 is damaged by contact with a roll.

In the embodiment of the present invention, the glass plate is cut as long as the first region and the second region are divided and a clean cut surface substantially perpendicular to the first surface of the glass plate is formed. The method is not particularly limited. As a method for cutting the glass plate, as shown in FIGS. 8C and 8D, it is preferable to cut the glass plate by laser scribing from the first surface side of the glass plate. You may cut | disconnect by a laser scribe from the surface side of this, and you may cut | disconnect by a mechanical scribe from the 2nd surface side of a glass plate.

Hereinafter, laser scribe will be described.
In laser scribing, laser light from a carbon dioxide laser (CO ₂ laser) or the like is absorbed by the glass surface layer, and the part that absorbed the laser light generates heat, and compressive stress is locally generated in the part. When the part is cooled with cooling water or the like in a state where the compressive stress is generated, tensile stress is generated on the contrary, and the glass surface layer is cracked. The crack is generated two-dimensionally, preferably linearly. As a result, a scribe line is formed.
In addition to the CO ₂ laser, a CO laser, a YAG laser, or the like can also be used.

FIGS. 9A to 9E are diagrams for explaining an example of a processing principle by laser scribing.
First, as shown in FIG. 9A, an initial crack 314 for starting scribing is generated on the end face of the glass plate 310 using a diamond cutter or the like.
Next, as shown in FIG. 9B, the surface of the glass plate 310 is heated by irradiating the laser beam 320 from the end face of the glass plate 310 along the planned dividing line.
And as shown in FIG.9 (c), immediately after a heating, the area | region 330 near the rear end of a laser beam is rapidly cooled with a water jet etc. As shown in FIG.
Then, as shown in FIG. 9D, a crack develops in the surface layer of the glass plate 310 from the initial crack 314 provided on the end surface of the glass plate 310. As a result, scribe lines 315 are formed on the surface of the glass plate 310.
Thereafter, by dividing the glass plate along the scribe line 315, a glass plate 310 ′ having a cut surface as a clean cut surface 313 can be produced as shown in FIG.
The method of dividing the glass plate is not particularly limited, and may be a method of dividing mechanically or a method of dividing the glass plate by irradiating a laser beam on a scribe line.

Examples that specifically disclose the embodiments of the present invention will be described below. In addition, this invention is not limited only to these Examples.

In the following examples, a cover glass constituting a display device and a touch panel was produced and its characteristics were evaluated.

Example 1
As a glass plate before chemical strengthening (ion exchange), soda lime glass (mass% SiO ₂ : 71.3%, Na ₂ O: 13.0%, K ₂ O: 0.85%, CaO: 9.0) %, MgO: 3.6%, Al ₂ O ₃ : 2.0%, Fe ₂ O ₃ : 0.15%, SO ₃ : 0.1%), with a thickness of 0.7 mm and a short side of 400 mm × A glass plate having a long side of 500 mm was prepared.

A first step of immersing the prepared glass plate in a mixed molten salt (first salt, ratio P: 25 mol%) bath composed of 75 mol% potassium nitrate and 25 mol% sodium nitrate held at 475 ° C. for 2 hours. , By performing a second step of immersing in a molten salt (second salt, ratio Q: 0 mol%) bath substantially consisting of 100 mol% of potassium nitrate maintained at 435 ° C. for 1 hour. Reinforced treatment was applied.

For the glass plate after chemical strengthening, the number of interference fringes and their spacing were observed using a surface stress meter (manufactured by Toshiba Glass (currently manufactured by Orihara Seisakusho), FSM-60V) to determine the surface compressive stress and the glass plate. The depth of the compressive stress layer formed on the surface of each was measured. In the measurement with a surface stress meter, 1.52 was used as the refractive index of the glass composition of the soda lime glass, and 26.8 ((nm / cm) / MPa) was used as the photoelastic constant. A sodium lamp was used as the light source.
As a result, the surface compressive stress was 675 MPa, and the compressive stress layer depth was 12 μm.

At the same time, the interval _r 2 between the distance _{r 1,} the interference of the second from the glass surface stripes _{L 2} and the third interference fringe _{L 3} from the glass surface first interference pattern _{L 1} and the second interference pattern _{L 2,} and it was measured distance r ₃ from the glass surface the third interference fringe L ₃ and the fourth interference fringe L _4.
Then, when the value of r ₂ / r _{1 and} the value of r ₃ / r ₂ were calculated from the measured interval r ₁ , interval r ₂ and interval r ₃ , r ₂ / r ₁ = 0.61, r ₃ / r ₂ = 0.65.

Moreover, about the glass plate after chemical strengthening, the average fracture stress by a 4-point bending test was measured with the following method. This value can be used as an index of the end face strength on the touch sensor side (first surface side) when used as a cover glass constituting a display device and a touch panel.

The glass plate after chemical strengthening was scribed into a size of 120 mm × 60 mm using a mechanical scribing device (MS500, manufactured by Samsung Diamond Industrial Co., Ltd.), and individual pieces to be a cover glass were obtained by folding. In the obtained cover glass, when the surface opposite to the scribed surface was the first surface, a clean cut surface substantially perpendicular to the first surface was formed.

The clean cut surface of the cut glass plate was measured according to JIS B 0601: 2001 using a non-contact three-dimensional measuring device (manufactured by Mitaka Kogyo Co., Ltd., NH-3N), and the arithmetic average roughness of the end surface Ra and the maximum height roughness Rz of the end face were measured. At this time, Ra was 0.013 μm and Rz was 0.18 μm.

A four-point bending test was performed by supporting the cover glass so that a tensile stress was generated on the first surface of the cover glass, and an average fracture stress was measured.
In addition, when the fracture starting point exists in the plane, the data is excluded, and only those having the fracture starting point in the edge portion are regarded as valid samples. The number of valid samples at this time is 50, and the average fracture The stress was 563 MPa.

(Example 2)
A glass plate similar to that of Example 1 was prepared except that the thickness of the glass plate was changed to 0.55 mm. The glass plate before chemical strengthening was scribed into a size of 120 mm × 60 mm using a laser scribing device (manufactured by Remi Co., SC-7392S), and individual pieces to be a cover glass were obtained by folding. When the obtained cover glass was chemically strengthened in the same manner as in Example 1, the surface compressive stress was 740 MPa, the compressive stress layer depth was 12 μm, r ₂ / r ₁ = 0.67, r ₃ / A cover glass with r ₂ = 0.57 was obtained. When the arithmetic average roughness Ra of the end face and the maximum height roughness Rz of the end face were measured for the obtained cover glass in the same manner as in Example 1, Ra was 0.031 μm and Rz was 0.42 μm. It was. Similarly to Example 1, when the average breaking stress on the laser scribe side was measured by a four-point bending test, the number of effective samples was 8, and the average breaking stress was 757 MPa.

(Comparative Example 1)
A glass plate similar to that in Example 1 was prepared. The glass plate before chemical strengthening was scribed into a size of 120 mm × 60 mm using a mechanical scribing device in the same manner as in Example 1, and individual pieces to be a cover glass were obtained by folding. When the arithmetic average roughness Ra of the end face and the maximum height roughness Rz of the end face were measured in the same manner as in Example 1 without subjecting the obtained cover glass to chemical strengthening treatment, Ra was 0.013 μm, Rz. Was 0.14 μm. Similarly to Example 1, when the average breaking stress on the clean cut surface side was measured by a four-point bending test, the number of effective samples was 50, and the average breaking stress was 234 MPa.

(Comparative Example 2)
A glass plate similar to Example 1 was prepared except that the thickness of the glass plate was changed to 1.1 mm. The glass plate before chemical strengthening was scribed into a size of 120 mm × 60 mm using a mechanical scribing device in the same manner as in Example 1, and individual pieces to be a cover glass were obtained by folding. The obtained cover glass was chamfered with an allowance of 0.2 mm (18% of the thickness of the glass plate) from the top A shown in FIG. When the tempering treatment was performed, a cover glass having a surface compressive stress of 750 MPa, a compressive stress layer depth of 13 μm, r ₂ / r ₁ = 0.68, and r ₃ / r ₂ = 0.63 was obtained. For the obtained cover glass, the arithmetic average roughness Ra of the end face and the maximum height roughness Rz of the end face were measured in the same manner as in Example 1. As a result, Ra was 1.661 μm and Rz was 10.17 μm. It was. Moreover, when the average breaking stress was measured by a 4-point bending test in the same manner as in Example 1, the number of effective samples was 7, and the average breaking stress was 425 MPa.

Example 1, Example 2, Comparative Example 1 and Comparative Example 2 Cover Glass Thickness, Surface Compressive Stress, Compressive Stress Layer Depth, r ₂ / r ₁ Value, r ₃ / r ₂ Value, Arithmetic Average Table 1 shows the roughness Ra, the maximum height roughness Rz of the end face, the number of effective samples and the average fracture stress by a four-point bending test. As is clear from Table 1, the cover glass of Examples 1 and 2 had a higher average fracture stress value than the cover glasses of Comparative Examples 1 and 2. Therefore, it was confirmed that the cover glasses of Examples 1 and 2 have sufficient end face strength as compared with the cover glasses of Comparative Examples 1 and 2.

International application PCT / JP2012 / 074925 filed on September 27, 2012, international application PCT / JP2012 / 074926 filed on September 27, 2012, international application filed on September 27, 2012 The contents of PCT / JP2012 / 074929 and Japanese Patent Application No. 2013-002747 filed on January 10, 2013 are incorporated herein by reference in their entirety.

DESCRIPTION OF SYMBOLS 10 Display apparatus 100 Touch panel 110 Cover glass 111 Cover glass 1st surface 112 Cover glass 2nd surface 113 Clean cut surface 114 Chamfering surface 120 Touch sensor 200 Display panel 310 Glass plate

Claims

A display device comprising a display panel and a touch panel attached to the front surface of the display panel,
The touch panel
A cover glass having a first surface facing the front surface of the display panel, and a second surface opposite to the first surface;
A touch sensor formed on the first surface of the cover glass,
The cover glass is a chemically strengthened glass,
The cover glass has a surface compressive stress of 600 to 900 MPa and a compressive stress layer depth of 5 to 20 μm.
The display device according to claim 1, wherein the cover glass has a clean cut surface substantially perpendicular to the first surface and a chamfered surface formed at an edge of the second surface.
The display device according to claim 1, wherein the cover glass has a thickness of 0.3 to 3 mm.
The cover glass has two types of stress patterns, a stress distribution pattern A on the glass surface side and a stress distribution pattern B on the glass inner side, in the compressive stress layer, and the stress pattern A and the stress pattern B are respectively provided. in the case of approximated by a linear function, when the inclination of the stress pattern a and S a, the slope of the stress pattern B and S B, satisfy the relationship of S a> S B, and observation principle the waveguide effect The interference fringes of the cover glass are observed using a surface stress meter, and the distance between the first interference fringe and the second interference fringe from the glass surface is r 1 , the second interference fringe and the third interference fringe from the glass surface Where r 2 is the distance between the interference fringes and r 3 is the distance between the third and fourth interference fringes from the glass surface, at least one of r 2 / r 1 and r 3 / r 2 is Claims satisfying 0.3-0.7 The display device according to 1 or 2.
The display device according to any one of claims 1 to 3, wherein an arithmetic average roughness Ra of the clean cut surface of the cover glass is 0.07 µm or less, and a maximum height roughness Rz is 0.70 µm or less. .
The display device according to any one of claims 1 to 4, wherein an allowance for the chamfered surface of the cover glass is 3 to 35% of a thickness of the cover glass.
A manufacturing method of a display device comprising a display panel and a touch panel attached to the front surface of the display panel,
Providing a chemically strengthened glass plate having a surface compressive stress of 600 to 900 MPa and a compressive stress layer depth of 5 to 20 μm;
Forming a touch sensor in at least a first region and a second region on the first surface of the glass plate, respectively.
By cutting the glass plate so that the first region and the second region are divided and a clean cut surface substantially perpendicular to the first surface of the glass plate is formed, Producing at least two cover glasses in which the touch sensor is formed on the first surface;
Chamfering the edge of the second surface opposite to the first surface of the cover glass;
And disposing the first surface of the cover glass so as to face the front surface of the display panel.
The method for manufacturing a display device according to claim 6, wherein the cover glass has a thickness of 0.3 to 3 mm.
The cover glass has two types of stress patterns, a stress distribution pattern A on the glass surface side and a stress distribution pattern B on the glass inner side, in the compressive stress layer, and the stress pattern A and the stress pattern B are respectively provided. in the case of approximated by a linear function, when the inclination of the stress pattern a and S a, the slope of the stress pattern B and S B, satisfy the relationship of S a> S B, and observation principle the waveguide effect The interference fringes of the cover glass are observed using a surface stress meter, and the distance between the first interference fringe and the second interference fringe from the glass surface is r 1 , the second interference fringe and the third interference fringe from the glass surface Where r 2 is the distance between the interference fringes and r 3 is the distance between the third and fourth interference fringes from the glass surface, at least one of r 2 / r 1 and r 3 / r 2 is Claims satisfying 0.3-0.7 Method of manufacturing a display device according to 6 or 7.
9. The display device according to claim 6, wherein an arithmetic average roughness Ra of the clean cut surface of the cover glass is 0.07 μm or less and a maximum height roughness Rz is 0.70 μm or less. Manufacturing method.
The method for manufacturing a display device according to any one of claims 6 to 9, wherein an allowance for the chamfered surface of the cover glass is 3 to 35% of a thickness of the cover glass.
A cover glass having a first surface and a second surface opposite to the first surface;
A touch panel comprising a touch sensor formed on the first surface of the cover glass,
The cover glass is a chemically strengthened glass,
The cover glass has a surface compressive stress of 600 to 900 MPa and a compressive stress layer depth of 5 to 20 μm.
The cover glass has a clean cut surface substantially perpendicular to the first surface and a chamfered surface formed at an edge of the second surface.
The touch panel according to claim 11, wherein the cover glass has a thickness of 0.3 to 3 mm.
The cover glass has two types of stress patterns, a stress distribution pattern A on the glass surface side and a stress distribution pattern B on the glass inner side, in the compressive stress layer, and the stress pattern A and the stress pattern B are respectively provided. in the case of approximated by a linear function, when the inclination of the stress pattern a and S a, the slope of the stress pattern B and S B, satisfy the relationship of S a> S B, and observation principle the waveguide effect The interference fringes of the cover glass are observed using a surface stress meter, and the distance between the first interference fringe and the second interference fringe from the glass surface is r 1 , the second interference fringe and the third interference fringe from the glass surface Where r 2 is the distance between the interference fringes and r 3 is the distance between the third and fourth interference fringes from the glass surface, at least one of r 2 / r 1 and r 3 / r 2 is Claims satisfying 0.3-0.7 The touch panel according to 11 or 12.
The touch panel according to any one of claims 11 to 13, wherein an arithmetic average roughness Ra of the clean cut surface of the cover glass is 0.07 µm or less, and a maximum height roughness Rz is 0.70 µm or less.
The touch panel according to any one of claims 11 to 14, wherein an allowance for the chamfered surface of the cover glass is 3 to 35% of a thickness of the cover glass.
Providing a chemically strengthened glass plate having a surface compressive stress of 600 to 900 MPa and a compressive stress layer depth of 5 to 20 μm;
Forming a touch sensor in at least a first region and a second region on the first surface of the glass plate, respectively.
By cutting the glass plate so that the first region and the second region are divided and a clean cut surface substantially perpendicular to the first surface of the glass plate is formed, Producing at least two cover glasses in which the touch sensor is formed on the first surface;
And a step of chamfering the edge of the second surface opposite to the first surface of the cover glass.
The method for manufacturing a touch panel according to claim 16, wherein the cover glass has a thickness of 0.3 to 3 mm.
The cover glass has two types of stress patterns, a stress distribution pattern A on the glass surface side and a stress distribution pattern B on the glass inner side, in the compressive stress layer, and the stress pattern A and the stress pattern B are respectively provided. in the case of approximated by a linear function, when the inclination of the stress pattern a and S a, the slope of the stress pattern B and S B, satisfy the relationship of S a> S B, and observation principle the waveguide effect The interference fringes of the cover glass are observed using a surface stress meter, and the distance between the first interference fringe and the second interference fringe from the glass surface is r 1 , the second interference fringe and the third interference fringe from the glass surface Where r 2 is the distance between the interference fringes and r 3 is the distance between the third and fourth interference fringes from the glass surface, at least one of r 2 / r 1 and r 3 / r 2 is Claims satisfying 0.3-0.7 The method as set forth in 16 or 17.
The touch panel according to any one of claims 16 to 18, wherein an arithmetic average roughness Ra of the clean cut surface of the cover glass is 0.07 µm or less and a maximum height roughness Rz is 0.70 µm or less. Production method.
The method for manufacturing a touch panel according to any of claims 16 to 19, wherein an allowance for the chamfered surface of the cover glass is 3 to 35% of a thickness of the cover glass.