TW201215578A - Cover glass for flat panel displays and production method - Google Patents

Abstract

The present invention provides glass for cover glass for large display devices, said glass: having a surface compressive stress comparable to that when chemical strengthening has been conducted at a low temperature even when ion exchange has been conducted at a high temperature; undergoing little change in compressive stress even when a temperature change has occurred; and providing excellent productivity. The present invention pertains to a cover glass for flat panel displays obtained by chemically strengthening glass, and the molar ratio of Na20, Al2O3, MgO and ZrO2 in the glass before chemical strengthening satisfies formula (1). (Na20/2)/(Al2O3/2 + MgO + ZrO2) = 0.85...formula (1)

Description

201215578 VI. Description of the Invention: The present invention relates to a protective glass and a pot manufacturing method for a flat panel display, and a display device using the same. [Prior Art] In recent years, in a flat panel display (hereinafter also referred to as an FPD (nat Panel Display)), a configuration is adopted in which a thin plate-shaped glass is placed so as to be a wider area than an image display portion. The front of the display, thereby eliminating the convex portion of the frame and improving the aesthetics. In order to be disposed at the front, a method of separating the protective glass from the FPD panel is adopted, but in this method, since the appearance is impaired due to reflection between the glass and the air layer, it is preferable to use a resin or an adhesive sheet to glass and The FPD panel is joined to reduce the reflection on the interface. In recent years, as a home TV set, a large-sized TV set has been favored. When a FpD panel and a cover glass are directly joined to a large FPD of 32 以上 or more, the area of the cover glass becomes large, so if used 2.5 soda-lime glass such as rmn, the weight of the body itself becomes larger, and the load during transportation or installation becomes larger. Therefore, it is possible to use thinned and lightweight glass, for example, glass of 15 mm, 1.1 mm, and 0.7 mm, etc. If the glass is thinned, the strength will decrease. In order to solve this problem, it is necessary to use chemical strengthening. The tempered glass is obtained (for example, Patent Documents 1 and 2). [PRIOR ART DOCUMENT] [Patent Document 1] 158 027. 00 00 00 00 00 00 00 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ The problem to be solved] But when 'when the large-area glass plate is chemically strengthened as described above', if it is soda-lime glass, sufficient stress layer iceness cannot be obtained within the required time, and In order to increase the speed of ion exchange and set it to a high temperature, there is a disadvantage that the desired surface compressive stress cannot be obtained due to stress relaxation. In particular, when chemically strengthening a large-area glass plate, the temperature distribution in the glass surface becomes large, and stress unevenness is likely to occur on the chemically strengthened glass surface. The result 'is present on the chemically strengthened glass plate. It is prone to problems of warpage or undulation. The present invention has been made in view of the above problems, and an object of the invention is to provide a glass for a cover glass for a large-sized display device, which has a glass for protecting glass even when chemically strengthened at a high temperature. When the temperature is chemically strengthened at a low temperature, the surface compressive stress is the same. Therefore, even when a temperature change occurs, the change in the compressive stress is small, and the productivity is excellent. [Technical means for solving the problem] That is, the present invention is as follows. 1. A protective glass for a flat panel display, which is obtained by chemically strengthening glass, and a molar ratio of Na2〇, Al2Q3, and Zr〇2 in the glass before chemical strengthening: 158027.doc 201215578 (Na20 /2) / (Al203 / 2 + Mg0 + Zr02) $ 0.85 · · · (1). 2. The cover glass for a flat panel display according to the above 1, wherein the surface compressive stress of the glass chemically strengthened by kn〇3 at 45 ° C for 6 hours is 6 hours at 400 ° C by KN 〇 3 More than 75% of the surface compressive stress of the strengthened glass. 3. The cover glass for a flat panel display according to the above 1 or 2, wherein the strain point of the glass before the chemical strengthening is 53 Å. (: Above. 4. The protective glass for flat panel displays according to 1 or 2 above, the thickness of which is 丨5 mm or less. The size is 22 对 or more. 5. Protection for flat panel displays according to any one of the above 1 to 4 The glass, wherein the glass before the chemical strengthening is a glass having a composition of 50% to 80% of SiO 2 , 2 to 25% of Al 2 〇 3, 〇 10% of Li 20 , 0 to 18 ° / [2〇, 〇~15% of Mg〇, 〇~5% of CaO, and 〇~5% of Zr02. 6. As in any of the above 1 to 5 The cover glass for a flat panel display, wherein the glass before the chemical strengthening comprises an aluminosilicate glass of Si〇2, Al2〇3, Na20 and MgO. 7. Protection for a flat panel display according to any one of the above 1 to 5. The glass, wherein the glass before the chemical strengthening is a glass having a composition of 50% to 74% of SiO 2 , 1 to 1% by weight of Al 2 〇 3, and 6 to 14% of Na; 2 〇, 3 ~11./❶K2〇, 2~15% of MgO, 〇~6% of CaO and 0~5%

Zr〇2, and the total content of Si〇2 and 丨2〇3 is 75% or less, the total content of Na20 and K2〇 is 12 to 25%, and the total content of Mg〇 and ca〇 is 7 to 15 %. The protective glass for a flat panel display according to any one of the above 1 to 5, wherein the glass before the chemical strengthening is a glass having a composition represented by mol% and containing 68 to 80% of SiO 2 , 4 ~10% Al2〇3, 5~15% Na2〇, 0~1% K20, 4~15% MgO and 〇~1% Zr02. 9. The cover glass for a flat panel display according to any one of the above 1 to 4, wherein the glass before the chemical strengthening is a glass having a composition represented by mol% and containing 67 to 75% of SiO 2 and 0 to 4%. Al2〇3, 7~15% of Na20, 1~9% of K20, 6~14% of MgO and 〇~1.5% of Zr02, SiO2 and Al2〇3 are 71~75%, Na20 and K20 The total content is 12 to 20%, and if CaO is contained, the content is less than 1%. 10. A flat panel display device using the cover glass for a flat panel display according to any one of the above 1 to 9 as a cover glass β 11 · a method of chemically strengthening glass to manufacture a cover glass for a flat panel display The method, and the Na20, A1203, MgO and ZrO<Mo Erbi in the glass before chemical strengthening satisfy the formula (1): (Na20/2)/(Al203/2+Mg0+Zr02)S 0.85··. 1) 12. The method of u above, wherein the chemical strengthening of the glass is carried out at 4 〇〇 to 45 〇. 13. The method according to the above 11 or 12, wherein the strain point of the glass before the chemical strengthening is 530. (1) The method according to any one of the above 1 to 13, wherein the glass before the chemical strengthening is any one of (i) to (iv) below: (1) the composition contained in % by mole 50~80% of SiO2, 2~25% of Al2〇3, 〇~10〇/〇 of U2〇, 〇~18% of Na20, 〇~10% of K20, 158027.doc -6 - 201215578 0~15 % of MgO, 0 to 5% of CaO, and 0 to 5% of Zr〇2 glass (ii) in the form of Mohr. The composition of 50% to 74% of SiO 2 and 1 to 10% of Al 2 〇 3, 6~14% Na20, 3~11% K20, 2~15% MgO, 0~6% CaO and 0~5% Zr02, and the total content of Si〇2 and Al2〇3 is 75% The following content of 'Na20 and K20 is 12~25°/., the total content of MgO and CaO is 7~15% glass (iii) The composition represented by mol% contains 68~80% of SiO2, 4 ~10〇/〇 of Al2〇3,5~150/〇Na20' 0~1% of K20, 4~15% of MgO and 0~1% of Zr02 glass (iv) is expressed in mol% Containing 67~75% of SiO2, 0~4% of Al2〇3, 7~15% of Na20, 1~90/〇K20, 6~14% of MgO and 0~1.5% of 21"〇2' The total content of 81〇2 and 八12〇3 is 71~75%, and the total content of Na2〇 and K2〇 is 12~20°/. If it contains CaO, the content is less than 1% of glass. [Effects of the Invention] According to the present invention, it is possible to provide a temperature-dependent change in the surface compressive stress even when chemical strengthening is performed at a high temperature of, for example, 4 Torr or higher, and exhibits stable strengthening characteristics and productivity. The present invention will be described in detail below. In the method for producing a cover glass for a flat panel display of the present invention, in addition to the composition of the glass subjected to the chemical strengthening treatment and the chemical strengthening treatment step, It is not particularly limited, and may be appropriately selected as long as it is a conventionally known step of 158027.doc 201215578. For example, the raw materials of the respective components are blended into a composition described later, and then heated in a glass refining furnace (4). The glass is homogenized by foaming, miscellaneous, clarified addition, etc. and formed into a glass plate of a specific thickness by a conventionally known forming method, and then slowed down. Examples of the glass forming method include a float method, a press method, a melting method, and a down-draw method. Particularly preferred is a float method suitable for mass production. Further, a continuous molding method other than the float method, that is, a melting method and The pulldown method is also preferred. The formed glass is ground and polished as needed, and subjected to chemical strengthening treatment, followed by washing and drying. 1. Glass before chemical strengthening As a glass for chemical strengthening treatment, a glass containing an alkali ion having a small ionic radius (for example, an alkali metal ion having a smaller ionic radius than potassium) is used. The composition of the glass is sufficient to impart surface compressive stress, and it is preferable to contain the thickness of the compressive stress layer in a short time.

Si02, Na20, K20, Al2〇3 and Mg〇.

Si〇2 forms an essential component of the glass skeleton.

Na20 is a component which is mainly substituted by potassium ions in the ion exchange treatment, whereby chemical strengthening of the glass is carried out, and the coefficient of thermal expansion is controlled to lower the high-temperature viscosity of the glass and to improve the meltability or formability. The component which improves the meltability of the lanthanum is "and" if it coexists with NajO, the compressive stress layer can be accommodated deep in a short time. Therefore, it is preferable to contain K20 in the case where a deeper compressive stress layer is to be imparted.

The Alz〇3 system has the effect of improving Tg, weather resistance, and Young's modulus, and further 158027.doc 201215578 improves the ion exchange performance of the glass surface.

The Mg lanthanum damages the enamel and enhances the melting properties of the glass.

Zr〇2 is a component that enhances the ion exchange rate and enhances the chemical durability or hardness of the glass, and sometimes contains Zr〇2. The inventors of the present invention have changed the composition of the glass before chemical strengthening, and even if the chemical strengthening is performed at the temperature, the decrease in the surface compressive stress is also aimed at the small glass. The correlation between the change of the surface compressive stress and the change of the surface of the glass before the strengthening of the glass was studied. As also shown in the examples, it was found that, as shown in Fig. 4, the vertical axis (7) was again reduced to the surface compressive stress of the glass which was chemically strengthened by KN 〇 3a at 450 ° C for 6 hours (Sod KN〇3 is a ratio of (S45〇/s_) of the surface compressive stress (S4〇〇) of the glass which is chemically strengthened for 6 hours at 4〇〇<>c, and the horizontal axis (X) is set to be before chemical strengthening. The molar ratio of Na2〇, Al2〇3, MgO and Zr〇2 in the composition of glass [(called (five) running /: hat buckle + heart (6)], then appears by the formula (y=_0.4374x+1.1035) The inventors of the present invention have focused on the fact that if the total content of Ah 〇 3 and MgO in the composition of the glass before chemical strengthening is large, the surface compressive stress is used even when chemical strengthening is performed at a high temperature. The decrease was also small, and the ratios of the components with the highest correlation were found in the above correlations. The ratio of the components with the highest correlation among the data was found. NaaO ' Ah〇3 'MgO and Zr〇 in the glass before chemical strengthening The molar ratio of 2 to the glass satisfying the following formula (1) appears even if chemical strengthening is carried out 158027.doc •9- 201215 In the case of 578, the change in surface compressive stress is also small. (Na2〇/2)/(Al2〇3/2+MgO+Zr02)$0.85. Formula (1) The above formula (1) has the following Technical significance: When the number of intermediate acid ions is relatively strong, the stress drop is small, and when the number of sodium ions increasing the compressive stress is large, the stress drop is likely to occur. (Na20/2)/(Al203/2+Mg0+Zr02) (hereinafter, referred to as X) may be 0.85 or less, preferably 〇75 or less. By setting χ to the range, Obtaining the effect of maintaining a sufficient compressive stress value while reducing the change in surface compressive stress when the temperature has changed. That is, if X is 0.85 or less, the equation according to the above correlation is used (y=-0.4374x+ll〇35) ), (S450/S400) becomes 〇.75 or more, which is larger than 0.72 of the sodium word glass (Example 12 of Table 2 described later in the embodiment), and can be obtained even if it is 22 对 or larger than the large area In the case of a glass plate, the warp or undulation also has a small effect. Further, 'X is preferably 0.4 or more. By setting x to 〇·4 or more, NazO in the glass The amount becomes sufficient 'a sufficient compressive stress can be obtained, and the strength of the glass can be increased. The glass for chemical strengthening in the present invention is preferably a surface compressive stress of glass which is chemically strengthened by KN〇3 at 450 ° C for 6 hours. It is 75% or more of the surface compressive stress of the glass which is chemically strengthened by kn〇3 at 400 ° C for 6 hours, more preferably 80% or more, and particularly preferably 85% or more. The surface compressive stress of the glass which was chemically strengthened by KN〇3 at 450 ° C for 6 hours was set to 400 by KN 〇 3 . (: 75% or more of the surface compressive stress of the glass which was chemically strengthened for 6 hours, thereby obtaining a surface compressive stress even when 158027.doc -10·201215578 was chemically strengthened at a high temperature of 400 C or higher. The protective glass having a small change in temperature and time and excellent in productivity with stable strengthening characteristics. The strain point of the glass before chemical strengthening in the present invention is preferably 53 〇t: or more. The reason is that by chemical The strain point of the glass before strengthening is set to 530C or more. It is not easy to produce the relaxation of surface compressive stress. The molar ratio of Na2〇, AhO3, MgO and Zr〇2 satisfies the above formula (1), and is 450° by KNO3. The surface compressive stress of the glass which was chemically strengthened for 6 hours was 75% or more of the surface compressive stress of the glass which was chemically strengthened by KN〇3 at 400 ° C for 6 hours, and the following (i) 〜 (iv) Any of the glasses. (1) The composition expressed in mole % contains 50 to 80% of SiO 2 , 2 to 25% of Al 2 〇 3, 〇 〇〇 1 〇〇 / 0 ^ 2 〇, 〇 〜 18% Na20, 〇~1〇% κ_2〇, 0~15% MgO, 0~5% Ca O and 0 to 5% of Zr02 glass (ii) in the form of molybdenum /. The composition is 50 to 74% of SiO 2 , 1 to 10% of Al 2 〇 3, 6 to 14% of Na 20 , 3 to 11% K20, 2-15% of MgO '0~6% of CaO and 0~5% of Zr02, and the total content of SiO2 and Al2〇3 is 75% or less, and the total content of Na2〇 and K20 is 12~ 25%, the total content of MgO and CaO is 7 to 15 ° /. Glass - (iii) The composition expressed in mole % contains 68 to 80% of SiO 2 , 4 to 10%

Al2〇3, 5~15% Na20, 0-1% κ20, 4~15% MgO and 0~1°/. The glass (iv) of ZrO 2 is composed of 67% to 75% of Si〇2, 〇~4% of Al2〇3, 7~15% of Na20, and 1 to 9% of K20, 6~14. The total amount of MgO and 158027.doc -II - 201215578 is 71~75%, and the total content of Na2O and K2O of Z02, Si02 & Al2〇3 is 0~1.5°/〇 if CaO is contained. For i2~20%, less than 1% of the glass is more typical than the total content of '_2 and 八12〇3 in the glass of the above (Hi) is 80% or less. 2. Chemical strengthening (4) Chemical (4) Treatment refers to the treatment of replacing the ions with a small ionic radius of the surface of the glass (for example, nanomaterials) into ions of a semi-pure ion (for example, unloading ions). For example, chemical strengthening treatment can be carried out by treating a glass containing sodium ions with a molten salt containing potassium ions. By performing such an ion-crossing process, the composition of the compressive stress layer on the surface of the glass is slightly different from that of the group before the ion exchange treatment, but the composition of the deep portion of the substrate and before the ion exchange treatment The composition is roughly the same. (Molten salt) When the above-mentioned composition is used as the glass for chemical strengthening, the smelting salt used for the chemical strengthening treatment is preferably a treated salt containing at least an unremoved ion. As such a treatment salt, for example, it is preferable to exemplify that the nitric acid is unloaded in the following eight times without mass% H H t f i H expressed by mass percentage. Sometimes it may also contain sodium succinate. However, there is a case where the surface compressive stress value is lowered by sodium ions. In order to obtain sufficient surface compressive stress by A, the content of sodium nitrate in the molten salt is preferably 10% or less. Further, it is more preferably 8% or less and further preferably 5% or less. It can also contain other ingredients in the Kunming refinery salt. Examples of the other 158027.doc 201215578 include sulfuric acid metal salts such as sodium sulfate and sulfuric acid, and alkali metal chlorides such as sodium chloride and potassium chloride. (Conditions of Chemical Strengthening Treatment) In the present invention, the treatment conditions of the chemical strengthening treatment are not particularly limited, and may be appropriately selected from previously known methods. (1) Heating temperature of molten salt The heating temperature of the molten salt is preferably 35 (TC or more, more preferably 38 〇〇 c or more, and still more preferably 400. (: Above, further preferably 5001 or less, more preferably It is 480 ° C or less, and more preferably 450 ° C or less. By setting the heating temperature of the molten salt to 35 (TC or more, it is difficult to prevent chemical strengthening due to a decrease in ion exchange rate. Further, by melting the salt When the heating temperature is set to 50 (sec or less, decomposition degradation of the molten salt can be suppressed. (2) Treatment time In order to impart sufficient compressive stress, the time for bringing the glass into contact with the molten salt is preferably 1 hour or longer, more preferably 2 hours. Further, in the long-term ion exchange, the 'productivity is lowered' and the compressive stress value is lowered by the relaxation, so it is preferably 24 hours or shorter, more preferably 2 hours or less. The thickness of the cover glass of the present invention is preferably The u mm is diagonally 22 吋 or more... The protective glass of the present invention has the following defects. Even if the thickness is as thin as 1.5 mm or less, and the size is set to be larger than the diagonal angle 吋, it is sufficient. Strength, not easy to self The shape of the display device can improve the aesthetics or display quality of the display device. The size of the display device is 32 吋 or more. 158027.doc 201215578 The cover glass of the present invention is made of a protective glass for a flat panel display device. A schematic side view of a flat panel display device (hereinafter, simply referred to as a display device) in the embodiment. As shown in Fig. i, the display device 10 includes a display panel 20 and a cover glass 3. The cover glass 30 is mainly used to lift the display device 1. For the purpose of aesthetics or strong production, prevention of impact damage, etc., a protective glass 3Q system is provided in front of the panel 20. For example, the protective glass 30 can be displayed away from the display panel 2 as shown in the figure. The side (front side) is provided in a manner of having an air layer. In this case, the cover glass 30 and the display panel 2 can be integrated via the frame 12. Further, the cover glass 30 can also be as shown in FIG. Generally, it is attached to the display side (front side) of the display panel 2A. For example, the cover glass 3 can be attached to the display panel 2 via a translucent adhesive film (not shown). The film may be of a general configuration, and the material or shape thereof is suitably selected. As shown in FIG. 3, the protective glass 3 can be suppressed by setting a gap between the protective glass 3 and the display panel 2A. 〇 (or display panel 2〇) reflection of light at the interface with the gap. As a result, the quality of the display device 10 can be improved. Further, the display device 10 can be made thinner. The front surface 31 from which the light from the display panel 20 is emitted, and the back surface 32 on which the light from the display panel 20 is incident. The functional film 40 may be placed on the front surface 31 or/and the surface 32. Further, the functional film 4〇 In Fig. i, it is disposed on the front face 31 and the back face 32, and is disposed on the front face 31 in Fig. 3. The functional film 40 has functions such as preventing reflection of ambient light, preventing impact damage, shielding electromagnetic waves, shielding near infrared rays, correcting color tone, or/or improving damage resistance. The functional film 40 is formed by attaching, for example, a film made of a resin to the protective glass 30. Alternatively, the functional film 4 may be formed by a thin film formation method such as a vapor deposition method, a sputtering method, or a CVD (ChemiCal Vapor Deposition) method. The functional film 4A can be a general structure, and its thickness, shape, and the like are appropriately selected depending on the use. On the back surface 32 of the cover glass 30, a decorative layer 50 is provided along at least a part of the peripheral portion. The decorative layer 5 can also be disposed to surround the outer periphery of the display panel 2A. The decorative layer 5 is provided for the purpose of improving the protection of the glass clasp and even the design or decorative nature of the display device 10. For example, when the decorative layer 50 is colored black, when the display device (10) is turned off, the peripheral surface of the cover glass 3G is included, and the front surface 31 of the protective glass 3 does not emit light at all. Therefore, the appearance of the display device (给予) gives the user a distinct impression and an aesthetic appearance (4) improvement. The method of forming the decorative layer 50 is not limited. For example, there is a method in which an ink containing pigment particles is applied to a protective glass, and after ultraviolet irradiation or heating and baking, cooling is performed to form a decorative layer. 5〇. Pigment = Sub: It consists of an organic pigment, an inorganic pigment, etc., and the ink is prepared by mixing the pigment particles into an organic vehicle. [Examples] Although the present invention is carried out on (4), the present invention is not limited to the examples (manufacture of chemically strengthened glass) in the beginning of the pile, and the glass of the composition shown in Table 2 and the percentage of moles. 158027.doc 201215578 The glass material is heated to 丨4〇〇~1650°C to be melted, clarified, and then cast into a mold to produce glass. After the glass is solidified, the glass is transferred to an electric furnace heated to near the slow cooling point of the glass, and slowly cooled to room temperature to obtain a glassy soil. The glass was polished from both sides of the glass block to a thickness of 1.0 mm and 5.0 cm x 5.0 cm. The glass was subjected to chemical strengthening treatment by immersing the glass in KNO3 maintained at 400 〇 c or 4501 for 6 hours to obtain tempered glass. Tables 1 and 2 show the results of evaluation of the glass before the chemical strengthening treatment and the glass after the chemical strengthening treatment by the following evaluation methods. Furthermore, in Tables 1 and 2, the value of ° is expressed in 〇. In Tables 1 and 2, Examples 1 to 11 are examples, and Examples 12 to 15 are comparative examples. (Evaluation method) The glass having the composition shown in Tables 1 and 2 corresponds to the change point Tstr (unit:), the glass transition point Tg (unit: .c), the specific gravity d, and the thermal expansion coefficient α (the method shown below). Unit: 1{r7/〇c), Yang type modulus £ (unit: 〇ρ&), Passon ratio σ is measured or evaluated. • Strain point The strain point is measured by the fiber elongation method according to JISR3 1〇3_2 (2〇〇1). • Glass transition point Using a differential thermal dilatometer, quartz glass was used as a reference sample to measure 5 from room temperature. The elongation of the glass at the time of the temperature rise is until the glass is softened and the temperature at which the stretching is not observed, that is, the deformation point, the temperature at the critical point in the thermal expansion curve is taken as the glass transition point. 158027.doc 201215578 • Specific gravity Determined by the Archimedes method. • Thermal expansion coefficient The thermal expansion coefficient at 50 to 350 ° C was calculated from the thermal expansion curve obtained by the same measurement method as the above Tg measurement. ^ • Yang Modulus and Passon Ratio The Yang Modulus and Passon Ratio are measured by ultrasonic pulse method on a glass plate with a thickness of 4 mm and a size of about 4 cm X 4 cm. Further, it was measured at 40 (TC and 450.) (the surface compressive stress S4〇0 (unit: MPa), s 4 5 〇, dry position. MPa) when the glass was chemically strengthened, and Calculate the ratio of S450 to S400 S45〇/S4. • The surface compressive stress of the surface compressive stress glass is measured using a surface stress meter FSM-6000 manufactured by Ohara. The same is shown in Tables 1 and 2. The composition of X (Na2〇/2)/(Al203/2+Mg0+Zr02) as the horizontal axis 'will be 450 by kn〇3. (: Surface compressive stress of glass which was chemically strengthened for 6 hours (S45〇) The ratio (S45〇/S4〇0) of the surface compressive stress (S4〇〇) of the glass which was chemically strengthened by kn〇3 at 400 ° C for 6 hours was plotted as a vertical axis. The molar ratio of Na2〇, Al2〇3, MgO, and Zr〇2 in the composition of the glass before chemical strengthening [(Na2〇/2)/(Al203/2+MgO+Zr02)] is the horizontal axis (x), With the surface compression stress (S4()()) of the glass by KN〇3 and the chemical strengthening of the glass by KN〇3 and the chemical strengthening of the glass by KN〇3 at 450 ° C for 6 hours. Compression should The ratio of (S45〇) (s45()/S4QQ) is 158027.doc 201215578 The vertical axis (y) shows the correlation expressed by the formula (y=-0.4374x+l.1035) [Table 1] Example 1 2 cases 3 cases 4 cases 5 cases 6 cases 7 cases 8 Si02 63.4 63.9 64.4 73.0 72.0 72.0 71.3 73 AI2O3 5.0 5.4 6.0 7.0 6.0 7.0 2.0 7.0 Na20 9.4 9.6 12.0 14.0 12.0 11.0 10.8 14.0 κ2ο 8.9 9.1 4.0 0 0 0 4.6 0 MgO 7.9 5.4 11.0 6.0 10.0 10.0 10.4 5.5 CaO 4.0 4.0 0.1 0 0 0 0.3 0 SrO 0.1 0.1 0.1 0 0 0 0 0 BaO 0 0 0 0 0 0 0 0 Zr02 1.3 2.5 2.5 0 0 0 0.5 0.5 X 0.40 0.45 0.36 0.74 0.46 0.41 0.45 0.74 Tstr (530) (530) 578 557 577 (620) 495 (570) Tg 577 575 620 617 647 674 547 625 S400 635 636 984 907 960 945 618 928 S450 621 616 947 728 881 928 489 755 S450/S400 0.98 0.97 0.96 0.80 0.92 0.98 0.79 0.81 d 2.53 2.55 2.53 2.41 2.41 2.41 2.44 2.42 a 107 98 91 79 72 68 96 77 E 75 76 78 71 73 73 73 73 σ 0.22 0.21 0.22 0.20 0.21 0.23 0.18 0.22 158027.doc •18- 201215578 [Table 2] Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 745^ Si02 72.5 64.4 76.5 70.6 78.6' ~~73 AI2O3 6.2 8.0 5.0 1.0 2 4.75 Na2〇12.8 12.5 14.5 12.4 13.4 16 K20 0 4.0 0 0.6 1.1 ' --- MgO 8.5 10.5 6.0 6.2 4 4 CaO 0 0.1 0 9.2 1 SrO 0 0.1 0 0.0 0 BaO 0 0.1 0 0.0 0 Zr02 0 0.5 0 0.0 0 0.5 X 0.55 0.42 0.85 0.92 1.34 1.16 Tstr (567) 556 (540) 511 (470) (480) Tg 527 604 (590) 550 515 530 S400 862 848 (723) 764 481 587 S450 703 720 (568 ) 548 273 276 S450/S400 0.82 0.85 (0.79) 0.72 0.57 0.47 d 2.41 2.48 (2.40) 2.50 2.44 2.43 a 74 98 (70) 85 82 (70) E 70 74 (73) 73 69 ~~(73) σ 0.22 0.23 (0.22) 0.23 0.16 (0.22) (0^22^ As shown in Tables 1 and 2, regarding chemical strengthening; history of the composition of the former glass

The molar ratio of Na20, Al2〇3, MgO and Zr02 satisfies the above formula (1),

The glass of Example 1 to 11 in which X is 0.85 or less, the surface compressive stress of the glass which was chemically strengthened by KN〇3 at 450 ° C for 6j was carried out by KN〇3 at 4〇〇t: The surface chemical stress-enhanced glass has a surface compressive stress of 75% or more. On the other hand, the molar ratio of 2Na2〇, Al2〇3, MgO, and Zr〇2 in the composition of the glass before chemical strengthening does not satisfy the above formula (1), and the parent exceeds 158027.doc -19-201215578 0.85. For the glass of 12~15, the surface compressive stress of the glass by κΝ03 with 45 (TC for 6 hours of chemical strengthening did not reach 400 by KN03. (: 75〇 of the surface compressive stress of the glass which was chemically strengthened for 6 hours) According to the results, it is understood that the molar ratio of Na20, Al2〇3, MgO, and Zr02 in the composition of the glass before chemical strengthening satisfies the above formula (1), and it can be obtained even at a high temperature of 400 ° C or higher. In the case of chemical strengthening, the surface compressive stress has a small change in temperature and time, and the glass has stable strengthening characteristics. The present invention has been described in detail using specific embodiments, but various modifications may be made without departing from the spirit and scope of the invention. The change and the deformation are clear to the practitioners in the field. Furthermore, this application is based on the patent application filed on August 24, 2012 (the special patent of this patent is 2〇1〇) _ 187523) 'And BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side cross-sectional view of a display device according to an embodiment of the present invention. Fig. 2 is a front view of Fig. 1. Fig. 3 is a side view of a modification of circle 1. Fig. 4 is a graph showing the correlation between the composition of the glass before chemical strengthening and the change in surface compressive stress during chemical strengthening. [Explanation of main component symbols] 10 Display device 12 Frame 20 Display panel 158027.doc • 20- 201215578 30 Protective glass 3 1 Front 32 Back 40 Functional film 50 Decorative layer 158027.doc -21 -

Claims (1)

201215578 VII. Patent application scope: 1. A protective glass for flat panel display, which is obtained by chemical strengthening of glass, and Mo20, Al2〇3, MgO and Zr〇2 in the glass before chemical strengthening. The ratio satisfies the formula (1): (Na2〇/2)/(Al2〇3/2+MgO+Zr〇2)$0.85···(1). 2. A protective glass for a flat panel display according to the item 1, wherein the surface compressive stress of the glass chemically strengthened by kno3 at 450 C for 6 hours is 400 by KNO3. (: 75% or more of the surface compressive stress of the glass which is chemically strengthened for a few hours. 3. The cover glass for flat panel display of claim 1 or 2, wherein the strain point of the glass before the chemical strengthening is 53 〇. 4. The protective glass for flat panel displays of claim 1 or 2 has a thickness of 1.5 mm or less and a size of 22 对 or more. 5. The protective glass for flat panel displays according to any one of claims 1 to 4. The glass before the chemical strengthening is a glass having a composition of 50% to 80% of SiO 2 , 2 to 25% of Al 2 〇 3, 0 to 10% of Li 2 〇, 〇 18% of Na20, 0 to 10% of 〇2〇, 〇~15% of MgO, 0 to 5% of CaO, and 0 to 5% of Zr02. 6. Protective glass for flat panel display according to any one of claims 1 to 5. The glass before the chemical strengthening is an aluminosilicate glass containing SiO 2 , Al 2 , 3 , Na 2 , and MgO. The protective glass for a flat panel display according to any one of claims 1 to 5, wherein the above chemical strengthening The glass is as follows: the composition expressed in mole % contains 50 to 74% of SiO 2 and 10% of Α 1 2〇3, 6-14% of 158027.doc 201215578 Na20, 3~11./. 20, 2~15% of MgO, 0~6% of CaO and 0~5./〇Zr02, and SiO2 and The total content of Al2〇3 is 75% or less, the total content of Na20 and K20 is 12 to 25%, and the total content of MgO and CaO is 7 to 15%. 8. Any one of claims 1 to 5 The cover glass for a flat panel display, wherein the glass before the chemical strengthening is a glass having a composition of 80% to 80% of Si 2 2, 4 to 10% of Al 2 3, 5 to 15%. Na20, 0 to 1% of K20, 4 to 15% of MgO, and 0 to 1% of Zr02. The protective glass for flat panel display according to any one of claims 1 to 4, wherein the glass system before the chemical strengthening is used. The following glass: the composition expressed in mole % contains 67 to 75% of Si〇2, 〇~4°/. Al2〇3, 7~15% of Na20, 1~9% of K20, 6~14% The total content of MgO and 0~1.5% of Zr02, Si02 and Al2〇3 is 7i~75%, and the total content of Na20 and K20 is 12~20% 'If it contains Ca〇, its content is less than ι〇/ 〇. 10·—a kind of flat panel display device’ The cover glass for a flat panel display according to any one of items 1 to 9 is used as a cover glass. 11. A method of chemically strengthening glass to produce a cover glass for a flat panel display, and Na2 in the glass before chemical strengthening The molar ratio of 〇, Al2〇3, MgO and Zr02 satisfies the formula (1): (Na20/2)/(Al203/2+Mg0+Zr02)g 0.85.·. (1) » 12. As requested in item 11 The method 'where the chemical strengthening of the glass is carried out at 4 〇〇 to 45 〇 <»c. 13. The method of claim 11 or 12, wherein the strain point of the glass before the chemical strengthening is 530 ° C or higher. The method of any one of claims 11 to 13, wherein the glass before the chemical strengthening is any one of (i) to (iv) below: (1) in the form of a molar. /〇 indicates that the composition contains 50~80% of SiO2, 2~25°/〇 of Al2〇3, 〇~1〇% of Li2〇, 〇~18% of Na20, 0~10〇/〇 of K20, 〇 ~15% of MgO, 0~5% of CaO and 0~5% of Zr02 glass (ii) The composition represented by mole % contains 50~74% of SiO2, 1~10% of Al2〇3,6~ 14% Na20, 3~11% K20, 2~150/〇MgO, 0~6% CaO and 0~5% Zr02, and the total content of SiO2 and Al2〇3 is 75% or less, Na20&amp The total content of K20 is 12 to 25%, the total content of MgO and CaO is 7 to 15% of glass (iii), and the composition represented by mole % contains 08-80% of SiO 2 , 4 to 10 〇 / 〇 Al2〇3, 5~15% Na20, 〇~1% K20, 4-15% MgO and 0~1% Zr〇2 glass (iv) expressed in mole % contains 67~75 °/. SiO2, 0~4% of Al2〇3' 7~15% of Na20' 1 ~9% of K2〇, 6-14% of MgO and 0~1.5% of Zr02, Si02 and Al2〇3 It is 71 to 75%, and the total content of Na20 and K20 is 12 to 20%, and if it contains CaO, the content is less than 1%. 158027.doc