KR100802521B1 - Substrate glass for display device - Google Patents

Abstract

The present invention is 63 to 69% by weight of SiO ₂ , 0.5 to 5% by weight of Al ₂ O ₃ , Na ₂ O 2 to 7% by weight, K ₂ O 8 to 17% by weight, MgO 10 to 18% by weight, CaO 0-7 The present invention relates to a substrate glass for a flat panel display device comprising a weight%, 0 to 3% by weight of SrO, 0 to 3% by weight of BaO, and 0.5 to 7% by weight of ZrO ₂ and having a distortion point of 570 ° C or higher.

Distortion, Display, Substrate Glass

Description

Substrate glass for display device {SUBSTRATE GLASS FOR DISPLAY DEVICE}

The present invention relates to a glass composition having excellent heat resistance, light weight and high strength. Particularly, glass substrates requiring the same thermal expansion coefficient and high heat resistance as conventional soda lime silica glass, for example, electrons such as PDP (plasma display panel), EL (electroluminescence), FED (field emission display), etc. It relates to a glass composition which is very suitable for a substrate for a display.

Conventionally, in the field of PDP manufacture, soda-lime silica glass whose thermal expansion coefficient of normal temperature -300 degreeC is about 80-90x10 <^-7> / degreeC, and distortion point about 510-520 degreeC has been used as substrate glass. Soda lime silica glass is advantageous in that it can be easily used at low cost because it is used in various ways. However, since the strain point is low, when the various heat treatments are performed in panel fabrication such as disposing an electrode wire pattern on the glass substrate and forming an insulating coating by low melting point glass, deformation of the substrate glass such as warpage or shrinkage occurs easily. There is a disadvantage.

In order to alleviate the above disadvantages, in recent years, alkali lime-based glass such as soda lime silica glass has proposed a high-distortion glass having a thermal expansion coefficient close to that of soda lime silica glass and having a strain point exceeding 550 ° C and exceeding 600 ° C. (For example, patent documents 1-3). These glasses have little thermal deformation in the manufacturing process of a display panel, and also the matching property of expansion with another member is good.

Patent Document 1: Japanese Patent No. 2738036

Patent Document 2: Japanese Patent Application Laid-Open No. 9-202641

Patent Document 3: Japanese Patent Application Laid-Open No. 9-255354

However, conventional high-distortion glass has a slightly unusual composition in comparison with soda lime silica glass, and the density of the conventional high-distortion glass is larger than soda lime silica glass and often exceeds 2.6. This not only has a problem that it is difficult to reduce the weight of the display device, but also causes a problem of bending due to its own weight of the glass substrate. That is, the curvature amount W by the weight of the glass substrate itself increases in proportion to the density ρ of the glass, as shown in formula (1). Therefore, when a glass substrate becomes large, the amount of curvature becomes very large, and a problem, such as a breakage, arises in the conveyance and movement process of a board | substrate.

W = c (ρ / E) (L ⁴ / t ² ) (1)

W: maximum bending amount, L: distance between two sides support, t: sheet thickness, ρ: glass density, E: Young's modulus of glass, c: integer

In addition, the conventional high-distortion glass has a weaker resistance than the soda lime silica glass, and thus has a problem of being easily broken when performing various treatments. In general, the rupture of the glass is considered to be a brittleness fracture occurring from the scratch (cracks), and the resistance to the fracture is called fracture toughness (K _IC ). Therefore, in order to improve the problem of rupture, glass having a high K _IC is required.

An object of the present invention is to provide a substrate glass characterized by having a linear expansion coefficient of the same degree as that of soda lime silica glass, high distortion point and high K _IC , and low density.

According to the present invention, 63 to 69 wt% SiO ₂ , 0.5 to 5 wt% Al ₂ O ₃ , _{2 to} 7 wt% Na ₂ O, _{8 to} 17 wt% K ₂ O, 10 to 18 wt% MgO, and CaO 0 to Substrate glass for a flat panel display device comprising 7% by weight, 0-3% by weight of SrO, 0-3% by weight of BaO and 0.5-7% by weight of ZrO ₂ and having a distortion point of 570 ° C or higher is provided.

According to the present invention, the glass is substantially 63 to 69% by weight of SiO ₂ , 0.5 to 5% by weight of Al ₂ O ₃ , Na ₂ O 2 to 7% by weight, K ₂ O 8 to 17% by weight, MgO 10 to 18 The glass may be composed of only 0% by weight, 0-7% by weight of CaO, 0-3% by weight of SrO, 0-3% by weight of BaO and 0.5-7% by weight of ZrO ₂ .

Si0 ₂ is the main component of the glass and when the weight percentage is less than 63%, the desired fracture toughness K _IC cannot be obtained as well as worsening the heat resistance or chemical durability of the glass. On the other hand, when it exceeds 69%, the high temperature viscosity of a glass melt will become high and glass molding will become difficult. In addition, the coefficient of linear thermal expansion of the glass becomes too small, resulting in poor compatibility with other members constituting the display panel. Therefore, it is 63 to 69%, Preferably it is 64 to 68% of range.

Al ₂ O ₃ is a component that increases the strain point and fracture toughness K _IC and is an essential component. If the weight% is less than 0.5%, the glass distortion and fracture toughness K _IC are lowered. On the other hand, if it exceeds 5%, the glass melt becomes difficult because the high temperature viscosity of the glass melt is increased and the opacity increases. Therefore, the range of 0.5 to 5%, suitably 1 to 4% is good.

Na ₂ O, together with K ₂ O, acts as a flux at the time of melting the glass and is also indispensable for maintaining the linear expansion coefficient of the glass at a suitable size. If it is less than 2%, the effect as a flux is insufficient, and the coefficient of linear expansion becomes too low. If it exceeds 7%, the distortion is too low. Therefore, it is 2 to 7%, Preferably it is 3 to 6% of range.

K ₂ O exhibits the same effect as Na ₂ O, and is an essential component that suppresses the movement of alkali ions by the mixed alkali effect with Na ₂ O and increases the volume resistivity of the glass. If it is less than 8%, this action is insufficient, and if it exceeds 17%, the coefficient of linear expansion becomes too large, and the distortion is also very low.

The K ₂ O content may be 14 to 17% or 15 to 17%. If the K ₂ 0 content is defined as the first glass to the glass of the present invention. In contrast, the K ₂ O content may be 8 to 15%, 8 to 14%, or 10 to 13%. If the K ₂ O content of the glass is defined as the second glass of the present invention.

MgO is an essential component that can increase the fracture toughness K _IC of the glass and increase the distortion. Less than 10% this action is insufficient. On the other hand, if it exceeds 18%, the opacity increases, so that molding of the glass becomes difficult. Therefore, it is 10 to 18%, Preferably it is 10.5 to 16% of range.

Although CaO is not an essential component, it has the effect | action which lowers the viscosity of the molten glass at the time of glass melting, and has the effect | action which raises the strain point of glass. Therefore, it may contain up to 7%. When it exceeds 7%, the hardness of the glass is increased to lower the fracture toughness K _IC , so it is preferably introduced in the range of 7% or less.

Although SrO and BaO are not essential components, they have a function of lowering the high temperature viscosity of the glass melt and suppressing the occurrence of opacity in the presence of CaO. If it exceeds 3%, the coefficient of linear expansion becomes too large, so it is preferable to make the range of 3% or less, respectively.

ZrO ₂ is an essential component having the effect of raising the strain point of the glass and improving the chemical durability of the glass, and it is preferable to contain 0.5% or more. If it exceeds 7%, the density increases, and the desired value cannot be maintained. Therefore, it is 0.5 to 7%, Preferably it is 1 to 6% of range.

B ₂ O _3, but is an essential component, because at the same time and having an effect of lowering the viscosity of the molten glass during the glass melting, to reduce the tendency of the opaque action may contain up to 5% or less. If it exceeds 5%, the strain point becomes too low, so it is preferable to introduce it in the range of 5% or less.

Li ₂ O is not an essential component, but lowers the high temperature viscosity of the glass and promotes melting of the glass raw material. However, if the content exceeds 3%, the distortion point is too low, it is preferable to introduce in the range of 3% or less.

The glass according to an embodiment of the present invention consists essentially of the above components, but may contain up to 3% of the other components in a weight% display in a range that does not impair the object of the present invention. For example, in order to improve the dissolution of glass, transparency, and moldability, S0 _3, Cl, F, As ₂ O _3, etc. may be contained in a total amount of up to 1%. Also it may contain a Fe ₂ 0 _3, CoO, NiO, such as to color the glass in a total amount up to 1%. In addition, TiO ₂ and CeO ₂ may be contained in amounts up to 1% and up to 1% in total amounts, for example, to prevent electron beam browning in the PDP.

When the distortion point is less than 570 ° C, deformation of the glass or the substrate is easily deformed when various heat treatments are performed in panel fabrication such as disposing an electrode wire pattern on a glass substrate and forming an insulating coating by low melting glass. There is a problem that happens.

Moreover, the glass of this invention may be in the range of 90 * 10 <^-7> / degreeC from 70 * 10 <^-7> / degreeC of average linear thermal expansion coefficient in 30 degreeC-300 degreeC. If it is out of this range, the compatibility with the other member which comprises a display panel may worsen.

Further, the first glass in the average coefficient of linear thermal expansion in ^{30 ℃ ~300 ℃ 86 × 10 -7} / ℃ in the range of 90 × 10 ^-7 / ℃ within, and from 87 × 10 ^-7 / ℃ 88 of the present invention It may be in the range of × 10 ⁻⁷ / ° C. If it is in the latter range among these ranges, an average linear expansion coefficient will become substantially the same as the average linear expansion coefficient of the soda-lime silica glass generally produced by the float method. On the other hand, in the 2nd glass of this invention, the average linear thermal expansion coefficient in 30 degreeC-300 degreeC may be in the range of 85x10 <^-7> / degreeC at 70 * 10 <^-7> / degreeC.

In addition, the glass of the present invention the fracture toughness K _IC may be more than 0.7 Mpa · m ^1/2. The fracture toughness K _IC is 0.7 MPa · m ^{l / 2} or less, may result in problem that easily broken out of the manufacturing process of the display device.

Moreover, the glass of this invention may be less than 2.6 g / cm <3> in density. If the density is 2.6 g / cm 3 or more, the value becomes larger than that of general soda lime silica glass, and when the display device is enlarged, problems such as deformation or fracture due to its own weight of the glass substrate may occur.

In the following, the non-limiting examples 1 to 5 shown in Table 1 and the non-limiting examples 1 to 8 shown in Table 2 illustrate the first and second glasses of the present invention, respectively. On the other hand, Comparative Examples 1-4 shown in Table 3 contrast with them.

(Examples 1-5, Examples 1-8 and Comparative Examples 1-4)

(Manufacture of Glass)

A combination raw material consisting of silica sand, aluminum oxide, sodium carbonate, sodium sulfate, potassium carbonate, magnesium oxide, calcium carbonate, strontium carbonate, barium carbonate and zirconium silicate was charged into a platinum crucible, and the furnace was 1500 to 1600 ° C for about 6 hours. Heat melting. The glass was homogenized by stirring the glass melt with a platinum rod during the heating melting. Subsequently, the molten glass was poured into a mold, and then introduced into an electric furnace maintained at 600 to 700 ° C. for cooling gradually, and then cooled in the furnace, Examples 1 to 5 and Tables 1 to 2 of Table 2 were used. 8 and the glass of the composition shown to the comparative examples 1-4 of Table 3 were obtained. The obtained glass sample was a homogeneous without bubble and striae.

In such glass, the strain point (° C.), average linear thermal expansion coefficient (10 ⁻⁷ / ° C.), fracture toughness K _IC (MPa · m ^1/2 ), and density (g / cm 3) were measured by the following method.

Distortion was measured by the beam bending method based on the provision of JIS R3103-2. The linear thermal expansion coefficient measured the average linear thermal expansion coefficient in 30-300 degreeC using the thermomechanical analyzer TMA 8310 (made by Rigaku Denki Co., Ltd.). Fracture toughness was calculated by the fracture toughness test method (indentation method) of fine ceramics described in JIS R 1607 using a microhardness DMH-2 (manufactured by Matsuzawa Seimitsu Kikai Co., Ltd.). The density was measured by the Archimedes method with respect to the glass without bubbles (about 50 g).

Example One 2 3 4 5 SiO ₂ 66.0 64.5 64.5 64.0 63.0 Al ₂ O ₃ 1.0 2.0 3.0 3.5 4.0 Na ₂ O 4.0 4.0 4.0 3.5 5.0 K ₂ O 15.5 15.5 15.5 16.5 14.0 MgO 11.0 11.5 10.5 10.0 10.0 CaO 0.5 SrO 0.5 1.0 BaO ZrO ₂ 2.5 2.5 2.0 2.0 3.0 Dwarf 570 573 570 572 570 density 2.491 2.496 2.485 2.483 2.512 Fracture Toughness K _IC 0.767 0.775 0.797 0.805 0.784 Coefficient of expansion 88 86 86 87 87

Example One 2 3 4 5 6 7 8 SiO ₂ 63.5 64.0 64.0 65.0 65.0 65.0 65.5 68.0 Al ₂ O ₃ 4.5 4.5 2.0 1.0 1.5 3.0 2.0 1.0 Na ₂ O 4.5 5.0 6.0 3.0 6.0 4.0 3.5 6.0 K ₂ O 14.0 10.5 8.5 11.0 8.0 11.5 11.5 8.0 MgO 10.5 11.5 15.0 10.5 13.0 11.0 11.0 16.0 CaO 0.5 0.5 0.5 2.0 1.5 1.0 1.0 SrO 0.5 0.5 3.0 0.5 0.5 BaO 0.5 1.0 ZrO ₂ 2.0 3.5 3.5 4.5 3.5 4.0 5.5 1.0 Dwarf 593 606 601 606 597 614 624 586 density 2.51 2.535 2.563 2.587 2.569 2.537 2.548 2.505 Fracture Toughness K _IC 0.87 0.838 0.834 0.774 0.806 0.819 0.819 0.875 Coefficient of expansion 85 76 79 72 79 76 71 77

Comparative example One 2 3 4 SiO ₂ 70.9 54.6 55.5 68.9 Al ₂ O ₃ 2.0 8.7 6.6 0.9 Na ₂ O 13.6 4.5 5.1 4.6 K ₂ O 0.8 8.2 6.4 4.8 MgO 3.6 2.9 1.2 0.1 CaO 9.1 7.4 2.2 9.7 SrO 9.3 6.7 BaO 9.9 9.0 0.4 ZrO ₂ 3.8 4.7 3.9 Dwarf 507 583 580 582 density 2.514 2.741 2.843 2.64 Fracture Toughness K _IC 0.73 0.65 0.67 0.64 Coefficient of expansion 87 85 83 75

(result)

The glass of Examples 1-5 of Table 1, and the glass of Examples 1-8 of Table 2 correspond to the 1st and 2nd glass of this invention, respectively. The glass of Comparative Example 1 is soda lime silica glass. The glass of Comparative Examples 2-4 is a conventional high distortion glass. In the soda lime silica glass of Comparative Example 1, the density is less than 2.6 and the fracture toughness K _IC is 0.7Mpa · m ^1/2, but the distortion point is markedly lower than that of the high distortion glass of Comparative Examples 2-4. . On the other hand, the high distortion glass of Comparative Examples 2-4 is high in 580 degreeC or more, but shows that the density exceeds 2.6 and the fracture toughness K _IC is less than 0.7 MPa * m ^1/2 .

Carried out in Table 1 in comparison to these Examples 1 to 5 and Table 2, the glass of Example 1 to 8 of is why sufficiently high point above 570 ℃, the density is less than 2.6, the fracture toughness K _IC is 0.75 MPa · m ^{1 / It} exceeds ² and fully satisfy | fills 0.7 MPa * m ^1/2 or more. Therefore, it is apparent that the glass of the present invention has a coefficient of linear expansion equivalent to that of soda lime silica glass, not only has heat resistance equivalent to that of conventional high-distortion glass, but also has a low density and high fracture toughness.

According to the present invention, it is possible to provide a high-distortion glass having a coefficient of thermal expansion similar to that of conventional soda lime silica glass, and having a low density and high fracture toughness K _IC . It is very suitable as a glass substrate for glass.

Claims (9)

63 to 69 weight percent SiO ₂ , 0.5 to 5 weight percent Al ₂ O ₃ , _{2 to} 7 weight percent Na ₂ O, _{8 to} 17 weight percent K ₂ O, 10 to 18 weight percent MgO, 0 to 7 weight percent CaO, SrO 0 to 3% by weight, BaO 0 to 3% by weight and ZrO ₂ 0.5 to 7% by weight, the distortion point K 570 ℃ or more, fracture toughness K _IC of 0.7 MPa · m ^1/2 or more, density 2.6g Substrate glass for flat panel display devices of less than / cm3. The method of claim 1, 63 to 69 weight percent SiO ₂ , 0.5 to 5 weight percent Al ₂ O ₃ , _{2 to} 7 weight percent Na ₂ O, _{8 to} 17 weight percent K ₂ O, 10 to 18 weight percent MgO, 0 to 7 weight percent CaO, 0~3% by weight of SrO, BaO 0~3 glass substrate for a flat panel display device comprising only 0.5~7 wt% ZrO _2% by weight. The method according to claim 1 or 2, Wherein the K ₂ 0 is a glass substrate for a flat panel display device that includes 14-17% by weight. The method according to claim 1 or 2, The K ₂ O is a glass substrate for a flat panel display device that includes 8-15% by weight. The method according to claim 1 or 2, 30 ℃ average linear thermal expansion coefficient is ^{70 × 10 -7 / ℃ ~90 ×} 10 substrate for the flat panel display device, characterized in that ^-7 / ℃ glass at ~300 ℃. The method of claim 3, wherein The average linear thermal expansion coefficient in 30 degreeC-300 degreeC is 86 * 10 <^-7> / degreeC-90 * 10 <^-7> / degreeC, The said board | substrate glass for flat panel display apparatuses characterized by the above-mentioned. The method of claim 4, wherein 30 ℃ average linear thermal expansion coefficient is ^{70 × 10 -7 / ℃ ~85 ×} 10 substrate for the flat panel display device, characterized in that ^-7 / ℃ glass at ~300 ℃. delete delete