TW201731787A - Glass substrate for flat panel displays and method for manufacturing same - Google Patents

Glass substrate for flat panel displays and method for manufacturing same Download PDF

Info

Publication number
TW201731787A
TW201731787A TW106118410A TW106118410A TW201731787A TW 201731787 A TW201731787 A TW 201731787A TW 106118410 A TW106118410 A TW 106118410A TW 106118410 A TW106118410 A TW 106118410A TW 201731787 A TW201731787 A TW 201731787A
Authority
TW
Taiwan
Prior art keywords
glass
mol
glass substrate
sio
flat panel
Prior art date
Application number
TW106118410A
Other languages
Chinese (zh)
Other versions
TWI644880B (en
Inventor
Akihiro Koyama
Satoshi Ami
Manabu Ichikawa
Original Assignee
Avanstrate Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=48697451&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=TW201731787(A) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Avanstrate Inc filed Critical Avanstrate Inc
Publication of TW201731787A publication Critical patent/TW201731787A/en
Application granted granted Critical
Publication of TWI644880B publication Critical patent/TWI644880B/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
    • C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B17/00—Forming molten glass by flowing-out, pushing-out, extruding or drawing downwardly or laterally from forming slits or by overflowing over lips
    • C03B17/06—Forming glass sheets
    • C03B17/064—Forming glass sheets by the overflow downdraw fusion process; Isopipes therefor
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B25/00—Annealing glass products
    • C03B25/04—Annealing glass products in a continuous way
    • C03B25/10—Annealing glass products in a continuous way with vertical displacement of the glass products
    • C03B25/12—Annealing glass products in a continuous way with vertical displacement of the glass products of glass sheets
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
    • C03B5/42—Details of construction of furnace walls, e.g. to prevent corrosion; Use of materials for furnace walls
    • C03B5/43—Use of materials for furnace walls, e.g. fire-bricks
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/133302—Rigid substrates, e.g. inorganic substrates
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K77/00—Constructional details of devices covered by this subclass and not covered by groups H10K10/80, H10K30/80, H10K50/80 or H10K59/80
    • H10K77/10—Substrates, e.g. flexible substrates
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/549—Organic PV cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
    • Y02P40/57—Improving the yield, e-g- reduction of reject rates
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Glass Compositions (AREA)
  • Liquid Crystal (AREA)
  • Electroluminescent Light Sources (AREA)
  • Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)

Abstract

The present invention provides: a glass substrate for flat panel displays, which has a good balance between low thermal shrinkage and suppression of devitrification; and a flat panel display. The glass substrate for the flat panel displays of the present invention contains, in mol%, 55-80% of SiO2, 8-20% of Al2O3, 0-8% of B2O3, more than 0% but 15% or less of MgO, 0-20% of CaO, 0-15% of SrO, and 0-10% of BaO, with SiO2 + 2 * Al2O3 being 100% or less. This glass substrate for flat panel displays has a molar ratio B2O3/(SiO2 + Al2O3) of 0-0.12, a molar ratio MgO/RO within the range of 0.15-0.9, a devitrification temperature of less than 1,280 DEG C, and a thermal shrinkage of 3 ppm or more but less than 75 ppm as calculated by the formula below after being heated from room temperature at 10 DEG C/min, maintained at 550 DEG C for 2 hours, and cooled to room temperature at 10 DEG C/min. Thermal shrinkage (ppm) = {amount of shrinkage of glass before and after heat treatment/length of glass before heat treatment} * 106.

Description

平面面板顯示器用玻璃基板及其製造方法Glass substrate for flat panel display and manufacturing method thereof

本發明係關於一種平面面板顯示器用玻璃基板及其製造方法。尤其，本發明係關於一種低溫多晶矽薄膜電晶體(以下記作LTPS-TFT(Low-Temperature-Polycrystalline-Silicon Thin-Film-Transistor))平面面板顯示器用玻璃基板之平面面板顯示器用玻璃基板。又，本發明係關於一種氧化物半導體薄膜電晶體(以下記作OS-TFT(Oxide-Semiconductor Thin-Film-Transistor))平面面板顯示器用玻璃基板之平面面板顯示器用玻璃基板。進而詳細而言，本發明係關於一種上述平面面板顯示器為液晶顯示器之平面面板顯示器用玻璃基板。或者係關於一種上述平面面板顯示器為有機EL(electroluminescent，電致發光)顯示器之平面面板顯示器用玻璃基板。The present invention relates to a glass substrate for a flat panel display and a method of manufacturing the same. In particular, the present invention relates to a glass substrate for a flat panel display of a glass substrate for a low-temperature polycrystalline germanium film transistor (hereinafter referred to as a LTPS-TFT (Low-Temperature-Polycrystalline-Silicon Thin-Film-Transistor)) flat panel display. Moreover, the present invention relates to a glass substrate for a flat panel display of an oxide semiconductor thin film transistor (hereinafter referred to as an OS-TFT (Oxide-Semiconductor Thin-Film-Transistor)) flat panel display glass substrate. More specifically, the present invention relates to a glass substrate for a flat panel display in which the above flat panel display is a liquid crystal display. Or a glass substrate for a flat panel display in which the above flat panel display is an organic EL (electroluminescent) display.

就行動裝置等所搭載之顯示器而言，出於可減少電力消耗等原因，期望將LTPS應用於薄膜電晶體(TFT)之製造，但於LTPS-TFT之製造中，必需以400~600℃之相對高溫進行熱處理。另一方面，近年來，對小型行動裝置之顯示器越來越要求高精細化。因此，引起像素之間距偏差之製造顯示器面板時產生的玻璃基板之熱收縮成為問題。又，即便於形成有OS-TFT之玻璃基板中，熱收縮之抑制亦同樣成為課題。 玻璃基板之熱收縮率一般可藉由提高玻璃之應變點或者降低熱膨脹係數而降低。 作為揭示著眼於熱收縮率之玻璃基板之文獻，有專利文獻1~2。專利文獻1~2均揭示關於液晶顯示器用玻璃基板之發明。 [專利文獻1]日本專利特開2004-315354號公報 [專利文獻2]日本專利特開2007-302550號公報In the case of a display mounted on a mobile device or the like, it is desirable to apply LTPS to the manufacture of a thin film transistor (TFT) for the purpose of reducing power consumption, etc., but in the manufacture of the LTPS-TFT, it is necessary to use 400 to 600 ° C. The heat treatment is performed at a relatively high temperature. On the other hand, in recent years, displays for small mobile devices are increasingly required to be highly refined. Therefore, heat shrinkage of the glass substrate which occurs when the display panel is manufactured, which causes variations in the pitch between pixels, becomes a problem. Moreover, even in the glass substrate in which the OS-TFT is formed, suppression of heat shrinkage is also a problem. The heat shrinkage rate of the glass substrate can generally be lowered by increasing the strain point of the glass or lowering the coefficient of thermal expansion. There are Patent Documents 1 to 2 as literatures for revealing a glass substrate focusing on heat shrinkage. Patent Literatures 1 to 2 disclose inventions relating to a glass substrate for a liquid crystal display. [Patent Document 1] Japanese Patent Laid-Open Publication No. 2004-315354 (Patent Document 2) Japanese Patent Laid-Open Publication No. 2007-302550

[發明所欲解決之問題] 專利文獻1中所記載之玻璃基板之應變點較高，但存在失透溫度較高，容易產生失透之問題。例如，專利文獻1中所記載之玻璃基板存在如下問題：若使用可省略玻璃基板表面之研磨步驟等而提昇生產性之溢流下拉法等成形方法，則失透問題變顯著。又，專利文獻2中所記載之玻璃基板之應變點並不足夠高，故而若欲使熱收縮率降低，則必需使成形後之平板狀玻璃於成為Tg附近之溫度範圍內之冷卻速度極慢。因此，專利文獻2中所記載之玻璃基板存在難以一面保持生產性一面降低熱收縮率之問題。 因此，本發明之目的在於提供一種可兼顧低熱收縮率及失透之抑制之玻璃基板。尤其，本發明之目的在於提供一種適於使用LTPS-TFT之平面面板顯示器之平面面板顯示器用玻璃基板及其製造方法。進而，目的在於提供一種即便於使用OS-TFT之平面面板顯示器中亦適用之可兼顧低熱收縮率及失透之抑制的平面面板顯示器用玻璃基板及其製造方法。 [解決問題之技術手段] 本發明者等人藉由對玻璃組成進行研究，發現可提供一種可兼顧低熱收縮率及失透之抑制之適於使用LTPS-TFT之平面面板顯示器之平面面板顯示器用玻璃基板，從而完成了本發明。進而，亦發現上述玻璃基板係亦可用作OS-TFT用之可兼顧低熱收縮率及失透之抑制者，從而完成了本發明。 本發明係如下所述。 [1] 一種平面面板顯示器用玻璃基板，其以莫耳%表示含有： 55~80%之SiO2 、 8~20%之Al2 O3 、 0~8%之B2 O3 、 超過0%~15%之MgO、 0~20%之CaO、 0~15%之SrO、 0~10%之BaO；且 SiO2 +2×Al2 O3 為100%以下； 莫耳比B2 O3 /(SiO2 +Al2 O3 )為0~0.12； 莫耳比MgO/RO(其中，RO為MgO、CaO、SrO及BaO之合計量)為0.15~0.9之範圍； 失透溫度未達1280℃； 自常溫以10℃/min升溫並以550℃保持2小時，其後，以10℃/min降溫至常溫後之由下述式所示之熱收縮率為3 ppm以上且未達75 ppm。 熱收縮率(ppm)={熱處理前後之玻璃之收縮量/熱處理前之玻璃之長度}×106 [2] 如[1]之玻璃基板，其以莫耳%表示含有： 63~72%之SiO2 、及 11~15%之Al2 O3 。 [3] 如[1]或[2]之玻璃基板，其中SiO2 -Al2 O3 /2為45~64%之範圍。 [4] 如[1]至[3]中任一項之玻璃基板，其以莫耳%表示含有： 63~70%之SiO2 、 12~15%之Al2 O3 、 1.5~7%之B2 O3 、 3~11%之MgO、 5~11%之CaO、 0~4%之SrO、 0~4%之BaO。 [5] 如[1]至[4]中任一項之玻璃基板，其以莫耳%表示含有： 0~2%之BaO。 [6] 如[1]至[5]中任一項之玻璃基板，其含有SnO2 及Fe2 O3 ；且 以莫耳%表示， SnO2 為0.03~0.15%， SnO2 及Fe2 O3 之合計量為0.05~0.2%之範圍。 [7] 如[1]至[6]中任一項之玻璃基板，其中以莫耳%表示， Li2 O、Na2 O及K2 O之合計量為0.01~0.5 mol%。 [8] 如[1]至[7]中任一項之玻璃基板，其實質上不含As2 O3 及Sb2 O3 。 [9] 如[1]至[8]中任一項之玻璃基板，其於100~300℃下之平均熱膨脹係數為28×10-7 ℃-1 以上且未達50×10-7 ℃-1 。 [10] 如[1]至[9]中任一項之玻璃基板，其係以溢流下拉法成形之玻璃基板。 [11] 一種平面面板顯示器，其係於玻璃基板表面形成有由LTPS或氧化物半導體形成之薄膜電晶體者，且上述玻璃基板為如[1]至[10]中任一項之玻璃基板。 [12] 如[11]之平面面板顯示器，其中平面面板顯示器為液晶顯示器或有機EL顯示器。 [13] 一種平面面板顯示器用玻璃基板之製造方法，其製造如[1]至[10]中任一項之平面面板顯示器用玻璃基板，且該製造方法包括以下步驟： 熔解步驟，其將調合成特定組成之玻璃原料熔解； 成形步驟，其將上述熔解步驟中熔解而成之熔融玻璃成形為平板狀玻璃；及 緩冷卻步驟，其係對上述平板狀玻璃進行緩冷卻之步驟，且係以降低上述平板狀玻璃之熱收縮率之方式控制上述平板狀玻璃之冷卻條件。 [14] 如[13]之製造方法，其中上述熔解步驟至少使用直接通電加熱而熔解玻璃原料。 [15] 如[13]或[14]之製造方法，其中上述熔解步驟係於至少含有高氧化鋯系耐火物而構成之熔解槽中熔解玻璃原料。 [16] 如[13]至[15]中任一項之製造方法，其中上述緩冷卻步驟係平板狀玻璃於Tg至Tg-100℃之溫度範圍內，以平板狀玻璃之冷卻速度達到30~300℃/min之方式進行緩冷卻。 [17] 一種平面面板顯示器用玻璃基板，其含有： 55~80%之SiO2 、 8~20%之Al2 O3 、 0~5%之B2 O3 、 超過0%~15%之MgO、 0~20%之CaO、 0~15%之SrO、 0~2%之BaO；且 SiO2 +2×Al2 O3 為100%以下； 莫耳比B2 O3 /(SiO2 +Al2 O3 )為0~0.12； 莫耳比MgO/RO(其中，RO為MgO、CaO、SrO及BaO之合計量)為0.15~0.9之範圍； 自常溫以10℃/min升溫並以550℃保持2小時，其後，以10℃/min降溫至常溫後之由下述式所示之熱收縮率未達60 ppm。 熱收縮率(ppm)={熱處理前後之玻璃之收縮量/熱處理前之玻璃之長度}×106 [發明之效果] 根據本發明，可提供一種能夠兼顧低熱收縮率及失透之抑制之平面面板顯示器用玻璃基板。尤其，可提供一種適於使用LTPS-TFT或OS-TFT之平面面板顯示器的平面面板顯示器用玻璃基板。[Problems to be Solved by the Invention] The glass substrate described in Patent Document 1 has a high strain point, but has a problem that the devitrification temperature is high and devitrification is likely to occur. For example, the glass substrate described in Patent Document 1 has a problem that the devitrification problem becomes remarkable when a molding method such as an overflow down-draw method in which the polishing step of the surface of the glass substrate can be omitted and the productivity is improved. Further, since the strain point of the glass substrate described in Patent Document 2 is not sufficiently high, if the heat shrinkage ratio is to be lowered, it is necessary to make the flat glass after molding have a very slow cooling rate in the temperature range near the Tg. . Therefore, the glass substrate described in Patent Document 2 has a problem that it is difficult to maintain the productivity while reducing the heat shrinkage rate. Accordingly, an object of the present invention is to provide a glass substrate which can achieve both low heat shrinkage rate and suppression of devitrification. In particular, it is an object of the present invention to provide a glass substrate for a flat panel display suitable for use in a flat panel display using LTPS-TFT and a method of manufacturing the same. Further, it is an object of the invention to provide a glass substrate for a flat panel display which is applicable to a flat panel display using an OS-TFT and which can achieve both low heat shrinkage rate and devitrification suppression, and a method for producing the same. [Means for Solving the Problem] The inventors of the present invention have found that a glass panel composition can be used to provide a flat panel display suitable for a flat panel display using LTPS-TFT which can achieve both low heat shrinkage rate and devitrification suppression. The glass substrate, thereby completing the present invention. Further, it has been found that the above-mentioned glass substrate can also be used as an OS-TFT for suppressing both low heat shrinkage rate and devitrification, and completed the present invention. The present invention is as follows. [1] A glass substrate for a flat panel display, which is expressed by mol%: 55 to 80% of SiO 2 , 8 to 20% of Al 2 O 3 , 0 to 8% of B 2 O 3 , more than 0% ~15% MgO, 0-20% CaO, 0-15% SrO, 0-10% BaO; and SiO 2 +2×Al 2 O 3 is 100% or less; Mobi B 2 O 3 / (SiO 2 +Al 2 O 3 ) is 0 to 0.12; Mohr is MgO/RO (where RO is the total amount of MgO, CaO, SrO and BaO) in the range of 0.15 to 0.9; the devitrification temperature is less than 1280 ° C The temperature was raised from normal temperature at 10 ° C / min and maintained at 550 ° C for 2 hours. Thereafter, after the temperature was lowered to 10 ° C / min to normal temperature, the heat shrinkage ratio represented by the following formula was 3 ppm or more and less than 75 ppm. The heat shrinkage rate (ppm) = {the amount of shrinkage of the glass before and after the heat treatment / the length of the glass before the heat treatment} × 10 6 [2] The glass substrate of [1], which is expressed in mol%, contains: 63 to 72% SiO 2 and 11 to 15% of Al 2 O 3 . [3] The glass substrate of [1] or [2], wherein SiO 2 -Al 2 O 3 /2 is in the range of 45 to 64%. [4] The glass substrate according to any one of [1] to [3], which is represented by mol%: 63 to 70% of SiO 2 , 12 to 15% of Al 2 O 3 , 1.5 to 7% B 2 O 3 , 3 to 11% of MgO, 5 to 11% of CaO, 0 to 4% of SrO, and 0 to 4% of BaO. [5] The glass substrate according to any one of [1] to [4], which is represented by mol%: 0 to 2% of BaO. [6] The glass substrate according to any one of [1] to [5] which contains SnO 2 and Fe 2 O 3 ; and is expressed by mol%, SnO 2 is 0.03 to 0.15%, SnO 2 and Fe 2 O The total amount of 3 is in the range of 0.05 to 0.2%. [7] The glass substrate according to any one of [1] to [6] wherein the total amount of Li 2 O, Na 2 O and K 2 O is 0.01 to 0.5 mol%, expressed as % by mol. [8] The glass substrate according to any one of [1] to [7] which is substantially free of As 2 O 3 and Sb 2 O 3 . [9] The glass substrate according to any one of [1] to [8], wherein the average thermal expansion coefficient at 100 to 300 ° C is 28 × 10 -7 ° C -1 or more and less than 50 × 10 -7 ° C - 1 . [10] The glass substrate according to any one of [1] to [9] which is a glass substrate formed by an overflow down-draw method. [11] A flat panel display in which a thin film transistor formed of LTPS or an oxide semiconductor is formed on a surface of a glass substrate, and the glass substrate is a glass substrate according to any one of [1] to [10]. [12] The flat panel display of [11], wherein the flat panel display is a liquid crystal display or an organic EL display. [13] A glass substrate for a flat panel display according to any one of [1] to [10], wherein the manufacturing method comprises the following steps: a melting step, which is to be adjusted a glass material for synthesizing a specific composition is melted; a forming step of forming molten glass obtained by melting in the melting step into a flat glass; and a step of cooling, which is a step of slowly cooling the flat glass, and The cooling conditions of the flat glass are controlled such that the heat shrinkage rate of the flat glass is lowered. [14] The production method according to [13], wherein the melting step melts the glass raw material using at least direct electric heating. [15] The production method according to [13] or [14] wherein the melting step is to melt the glass raw material in a melting tank comprising at least a high zirconia refractory. [16] The manufacturing method according to any one of [13] to [15] wherein the slow cooling step is a flat glass in a temperature range of Tg to Tg-100 ° C, and the cooling rate of the flat glass reaches 30~ Slow cooling was carried out at 300 ° C / min. [17] A glass substrate for a flat panel display, comprising: 55 to 80% of SiO 2 , 8 to 20% of Al 2 O 3 , 0 to 5% of B 2 O 3 , and more than 0% to 15% of MgO 0~20% CaO, 0~15% SrO, 0~2% BaO; and SiO 2 +2×Al 2 O 3 is 100% or less; Mo Erbi B 2 O 3 /(SiO 2 +Al 2 O 3 ) is 0 to 0.12; Mohr is MgO/RO (where RO is the total amount of MgO, CaO, SrO and BaO) in the range of 0.15 to 0.9; and is raised from normal temperature at 10 ° C/min to 550 ° C. After maintaining for 2 hours, the heat shrinkage ratio represented by the following formula after cooling to room temperature at 10 ° C / min was less than 60 ppm. Heat shrinkage rate (ppm) = {shrinkage amount of glass before and after heat treatment / length of glass before heat treatment} × 10 6 [Effect of the invention] According to the present invention, it is possible to provide a plane capable of achieving both low heat shrinkage rate and suppression of devitrification A glass substrate for a panel display. In particular, a glass substrate for a flat panel display suitable for use in a flat panel display using LTPS-TFT or OS-TFT can be provided.

本發明之平面面板顯示器用玻璃基板以莫耳%表示含有： 55~80%之SiO2 、 8~20%之Al2 O3 、 0~8%之B2 O3 、 超過0%~15%之MgO、 0~20%之CaO、 0~15%之SrO、 0~10%之BaO；且 SiO2 +2×Al2 O3 為100%以下； 莫耳比B2 O3 /(SiO2 +Al2 O3 )為0~0.12； 莫耳比MgO/RO(其中，RO為MgO、CaO、Sr0及BaO之合計量)為0.15~0.9之範圍； 失透溫度未達1280℃； 自常溫以10℃/min升溫並以550℃保持2小時，其後，以10℃/min降溫至常溫後之由下述式所示之熱收縮率為3 ppm以上且未達75 ppm。 熱收縮率(ppm)={熱處理前後之玻璃之收縮量/熱處理前之玻璃之長度}×106 以下，對本發明之平面面板顯示器用玻璃基板進行說明。 SiO2 係玻璃之骨架成分，因此為必需成分。若含量減少，則會有耐酸性降低，應變點降低，且熱膨脹係數增加之傾向。又，若SiO2 含量過少，則難以使玻璃基板低密度化。另一方面，若SiO2 含量過多，則會有熔融黏性顯著提高而難以熔解之傾向。若SiO2 含量過多，亦會有耐失透性降低之傾向。SiO2 之含量設為55~80 mol%之範圍。SiO2 之含量較佳為60~75 mol%，更佳為62~73 mol%，進而較佳為63~72 mol%，進一步較佳為63~70 mol%，更進一步較佳為65~70 mol%，進而進一步較佳為65~69 mol%，再進一步較佳為65~68 mol%之範圍。 Al2 O3 係抑制分相且提高應變點之必需成分。若Al2 O3 含量過少，則玻璃變得容易分相。又，若Al2 O3 含量過少，則應變點降低。進而，若Al2 O3 含量過少，則會有楊氏模數亦降低，取決於酸之蝕刻速率亦降低之傾向。若Al2 O3 含量過多，則會有玻璃之失透溫度上升而耐失透性降低，故而成形性惡化之傾向。就上述觀點而言，Al2 O3 之含量為8~20 mol%之範圍。Al2 O3 之含量較佳為8~18 mol%，更佳為9~17 mol%，進而較佳為11~15 mol%，進一步較佳為12~15 mol%，更進一步較佳為12~14 mol%之範圍。 B2 O3 係降低玻璃之高溫黏性並改善熔融性之成分。即，由於降低熔融溫度附近之黏性，故而可改善熔解性。又，B2 O3 亦為降低失透溫度之成分。若B2 O3 含量較少，則會有熔解性降低，耐失透性降低之傾向。若B2 O3 含量過多，則應變點降低，耐熱性降低。又，若B2 O3 含量過多，則楊氏模數降低。又，藉由玻璃成形時之B2 O3 之揮發，而容易產生失透。尤其，應變點較高之玻璃存在成形溫度增高之傾向，故而會促進上述揮發，失透之產生成為顯著之問題。又，藉由玻璃熔解時之B2 O3 之揮發，玻璃之不均質變得顯著，容易產生條紋。就上述觀點而言，B2 O3 含量為0~8 mol%，較佳為0~5 mol%之範圍。B2 O3 含量較佳為0.1~5 mol%，更佳為1.5~5 mol%，進而較佳為1.5~4.5 mol%之範圍。另一方面，於重視耐失透性之情形時，B2 O3 含量較佳為0~7 mol%，更佳為0.1~7 mol%，進而較佳為1~7 mol%，進一步較佳為1.5~7 mol%，更進一步較佳為1.5~6.5 mol%，進而進一步較佳為2~6 mol%之範圍。B2 O3 含量係考慮熔解性及耐失透性之兩者而適當決定。若考慮熔解性及耐失透性之兩者，則B2 O3 含量較佳為1~5 mol%，更佳為1.5~5 mol%，進而較佳為1.5~4.5 mol%之範圍。 MgO係提昇熔解性之必需成分。又，其係鹼土金屬中不易使密度增加之成分，故而若相對增加其含量，則容易實現低密度化。藉由含有MgO可提昇熔解性。但若MgO之含量過多，則玻璃之失透溫度急遽上升，故而尤其於成形步驟中容易失透。又，若MgO含量過多，則會有耐酸性降低之傾向。就上述觀點而言，MgO含量為超過0 mol%~15 mol%，較佳為1.5~15 mol%，更佳為2~15 mol%，進而較佳為2~12 mol%，進一步較佳為3~11 mol%，更進一步較佳為4~10 mol%，進而進一步較佳為5~9 mol%之範圍。 CaO係對不會急遽提高玻璃之失透溫度而提昇玻璃之熔解性有效之成分。又，其係鹼土金屬中不易使密度增加之成分，故而若相對增加其含量，則容易實現低密度化。若含量過少，則會有出現耐失透性降低之傾向。若CaO含量過多，則會有熱膨脹係數增加，且密度上升之傾向。就上述觀點而言，CaO含量為0~20 mol%，較佳為3~15 mol%，更佳為4~13 mol%，進而較佳為5~11 mol%，進一步較佳為7~11 mol%之範圍。 SrO係可降低玻璃之失透溫度之成分。SrO並非必需，但若含有SrO，則耐失透性及熔解性提昇。然而，若SrO含量過多，則密度會上升。就上述觀點而言，SrO含量為0~15 mol%，較佳為0~10 mol%，更佳為0~7 mol%，進而較佳為0~4 mol%，進一步較佳為0~2 mol%，更進一步較佳為0~1.5 mol%，進而進一步較佳為0~1 mol%之範圍。於欲降低玻璃之密度之情形時，較佳為實質上不含SrO。 BaO係可降低玻璃之失透溫度之成分。其並非必需成分，但若含有BaO，則耐失透性及熔解性提昇。然而，若BaO之含量過多，則密度會上升。又，就環境負荷之觀點、及存在熱膨脹係數增大之傾向之情況而言，BaO含量為0~10 mol%，較佳為0~4 mol%，更佳為0~3 mol%，進而較佳為0~2.5 mol%，進一步較佳為0~2 mol%，更進一步較佳為0~1 mol%，進而進一步較佳為0~0.5 mol%，再進一步較佳為實質上不含BaO。 Li2 O及Na2 O係有自玻璃基板溶出而使TFT特性劣化，或者增大玻璃之熱膨脹係數而於熱處理時損壞基板之虞的成分。較佳為實質上均不含Li2 O及Na2 O。 K2 O係提高玻璃之鹼性度，促進澄清性之成分。又，其係提昇熔解性，降低熔融玻璃之比電阻之成分。其並非必需成分，但若含有K2 O，則熔融玻璃之比電阻降低，而可防止電流於構成熔解槽之耐火物中流通，可抑制熔解槽被侵蝕。又，於構成熔解槽之耐火物含有氧化鋯之情形時，可抑制熔解槽被侵蝕而導致氧化鋯自熔解槽溶出至玻璃，故而亦可抑制由氧化鋯引起之失透。又，由於使熔解溫度附近之玻璃黏性降低，故而熔解性及澄清性提昇。另一方面，若K2 O含量過多，則會有自玻璃基板溶出而使TFT特性劣化之虞。又，會有熱膨脹係數亦增大之傾向。就上述觀點而言，K2 O含量較佳為0~0.8 mol%，更佳為0.01~0.5 mol%，進而較佳為0.1~0.3 mol%之範圍。 ZrO2 及TiO2 係提高玻璃之化學耐久性及應變點之成分。ZrO2 及TiO2 並非必需成分，但藉由含有ZrO2 及TiO2 可實現應變點之上升及耐酸性提昇。然而，若ZrO2 量及TiO2 量過多，則失透溫度明顯上升，故而有耐失透性及成形性降低之情況。尤其，ZrO2 之熔點較高而難熔，故而會引起原料之一部分堆積於熔解爐之底部等問題。若該等未熔解之成分混入至玻璃生坯中，則會作為內含物而引起玻璃之品質惡化。又，TiO2 係使玻璃著色之成分，故而對於顯示器用基板而言欠佳。就上述觀點而言，於本發明之玻璃基板中，ZrO2 及TiO2 之含有率分別較佳為0~5 mol%，更佳為0~3 mol%，進而較佳為0~2 mol%，進一步較佳為0~1 mol%。進而進一步較佳為本發明之玻璃基板中實質上不含ZrO2 及TiO2 。 ZnO係提昇耐BHF(Buffered Hydrofluoric acid，緩衝氫氟酸)性或熔解性之成分。但其並非必需成分。若ZnO含量過多，則會有失透溫度上升，應變點降低，且密度上升之傾向。就上述觀點而言，ZnO含量較佳為0~5 mol%，更佳為0~3 mol%，進而較佳為0~2 mol%，進一步較佳為0~1 mol%之範圍。較佳為實質上不含ZnO。 P2 O5 係降低高溫黏性，提昇熔解性之成分。但其並非必需成分。若P2 O5 含量過多，則藉由玻璃熔解時之P2 O5 之揮發，玻璃之不均質變得顯著，容易產生條紋。又，耐酸性明顯惡化。又，容易產生乳白。就上述觀點而言，P2 O5 含量較佳為0~3 mol%，更佳為0~1 mol%，進而較佳為0~0.5 mol%之範圍，尤佳為實質上不含P2 O5 。 本發明之玻璃基板可含有澄清劑。作為澄清劑，只要為對環境之負荷較小，玻璃之澄清性優異者，則無特別限制，例如可列舉選自Sn、Fe、Ce、Tb、Mo、Sb及W之金屬氧化物之群中之至少1種。作為澄清劑，較佳為SnO2 。澄清劑之含量若過少，則氣泡品質惡化，若含量過多，則會有成為失透或著色等之原因之情形。澄清劑之含量亦取決於澄清劑之種類或玻璃之組成。例如，SnO2 、Fe2 O3 及Sb2 O3 之合計量較佳為0.05~0.20 mol%。 SnO2 係即便為1600℃以上亦可獲得澄清效果之澄清劑，且係可使用於僅可微量含有鹼金屬氧化物之平面面板顯示器用玻璃基板(例如鹼金屬氧化物之合計量為0~0.8 mol%)之製造中的為數不多之澄清劑。然而，SnO2 為容易產生失透之成分，故而就抑制失透之觀點而言，不宜大量地添加。 又，應變點較高之玻璃(例如應變點為670℃以上之玻璃)與應變點較低之玻璃(例如應變點未達670℃之玻璃)相比，存在失透溫度容易變高之傾向，故而會有為抑制失透，不得不使成形步驟中之熔融玻璃之溫度高於應變點較低之玻璃之情形。此處，就耐潛變性、耐熱性之觀點而言，溢流下拉法中所使用之成形體較佳為包含含有氧化鋯之耐火物而構成。於採用溢流下拉作為成形方法之情形時，若欲提高成形步驟中之熔融玻璃之溫度，則亦必需提高成形體之溫度。然而，若成形體之溫度變高，則會有氧化鋯自成形體溶出，容易產生該氧化鋯之失透之問題。又，尤其是就較多地含有SnO2 之玻璃而言，會有因該氧化鋯而產生SnO2 之失透之虞。 進而，應變點較高之玻璃(例如應變點為670℃以上之玻璃)與應變點較低之玻璃(例如應變點未達670℃之玻璃)相比，存在熔解玻璃原料之溫度亦容易變高之傾向。此處，進行熔解步驟之熔解槽就耐侵蝕性之觀點而言較佳為包含含有氧化鋯之高氧化鋯系耐火物而構成。又，就能量效率之觀點而言，較佳為藉由電熔或電熔與其他加熱方法之組合而熔解玻璃原料。然而，於熔解如本發明所記載之具有高應變點，且僅可微量含有鹼金屬氧化物之玻璃之情形時，熔融玻璃之比電阻較大，故而容易產生電流於高氧化鋯系耐火物中流通，氧化鋯溶出至熔融玻璃中之問題。若氧化鋯溶出，則會有產生上述氧化鋯之失透及由氧化鋯引起之SnO2 之失透之虞。 即，就抑制由氧化鋯引起之SnO2 之失透之觀點而言，於本發明之玻璃基板中，超過0.2 mol%而含有SnO2 之情況亦欠佳。就上述觀點而言，SnO2 含量例如較佳為設為0.01~0.2 mol%之範圍，更佳為0.03~0.15 mol%，進而較佳為0.05~0.12 mol%之範圍。 Fe2 O3 係除具有作為澄清劑之作用以外，亦降低熔融玻璃之比電阻之成分。於高溫黏性較高且具有難熔解性之玻璃中，較佳為為了降低熔融玻璃之比電阻而含有Fe2 O3 。然而，若Fe2 O3 含量過多，則玻璃著色，穿透率降低。因此，Fe2 O3 含量為0~0.1 mol%之範圍，較佳為0~0.05 mol%，更佳為0.001~0.05 mol%，進而較佳為0.003~0.05 mol%，進一步較佳為0.005~0.03 mol%之範圍。 於本發明中，澄清劑較佳為組合使用SnO2 與Fe2 O3 。就失透之觀點而言，如上所述不宜較多地含有SnO2 。然而，為充分獲得澄清效果，需要含有特定值以上之澄清劑。因此，藉由併用SnO2 與Fe2 O3 ，可使SnO2 之含量不會多至產生失透之程度，而獲得充分之澄清效果，製作氣泡較少之玻璃基板。SnO2 與Fe2 O3 之合計量較佳為0.05~0.2 mol%之範圍，更佳為0.08~0.2 mol%，進而較佳為0.1~0.18 mol%，進一步較佳為0.1~0.15 mol%之範圍。 SnO2 之含量相對於SnO2 與Fe2 O3 之合計量之莫耳比(SnO2 /(SnO2 +Fe2 O3 ))若過大則容易產生失透，若過小則會有無法獲得充分之澄清效果，玻璃著色之情況。因此，較佳為0.55~1之範圍，更佳為0.6~1，進而較佳為0.65~1，進一步較佳為0.65~0.95，更進一步較佳為0.65~0.9之範圍。 本發明之玻璃基板就環境負荷之問題而言較佳為實質上不含As2 O3 。本發明之玻璃基板就環境負荷之問題而言較佳為含有0~0.6 mol%之Sb2 O3 ，更佳為0~0.1 mol%，最佳為實質上不含Sb2 O3 。 根據環境上之原因，本發明之玻璃基板較佳為實質上不含PbO及F。 再者，於本說明書中，所謂「實質上不含」係指於上述玻璃原料中不使用成為該等成分之原料之物質，並不排除其他成分之作為雜質包含於玻璃原料中之成分、自製造裝置溶出至玻璃之成分之混入。 SiO2 之含量與Al2 O3 之含量之2倍之合計量即SiO2 +2×Al2 O3 若過少則會有應變點降低之傾向，若過多則會有耐失透性惡化之傾向。因此，SiO2 +2×Al2 O3 為100 mol%以下，較佳為75~100 mol%，更佳為75~97 mol%，更佳為80~96 mol%，進而較佳為85~96 mol%，進一步較佳為85~95 mol%，更進一步較佳為87~95 mol%，進而進一步較佳為89~95 mol%，再進一步較佳為89~94 mol%。 關於SiO2 之含量與Al2 O3 之1/2之差SiO2 -Al2 O3 /2，若值過小，則雖蝕刻速率提昇，但有耐失透性降低之虞。若值過高，則會有蝕刻速率降低之虞。就上述觀點而言，SiO2 -Al2 O3 /2較佳為69 mol%以下，較佳為45~69 mol%，更佳為45~64 mol%，進而較佳為50~63 mol%，進一步較佳為55~62 mol%，更進一步較佳為55~61.5 mol%，進而進一步較佳為55~61 mol%。 莫耳比B2 O3 /(SiO2 +Al2 O3 )主要成為應變點及耐失透性之指標。如上所述，若B2 O3 含量較少，則熔解性及耐失透性降低。另一方面，若含量增多，則應變點降低，耐熱性降低。又，若含量增多，則會有耐酸性及楊氏模數降低之傾向。 關於B2 O3 /(SiO2 +Al2 O3 )亦基本存在相同之傾向。因此，莫耳比B2 O3 /(SiO2 +Al2 O3 )係設為0~0.12之範圍。若B2 O3 /(SiO2 +Al2 O3 )超過0.12，則會有無法充分提高應變點，耐失透性降低至接近0之程度之傾向。莫耳比B2 O3 /(SiO2 +Al2 O3 )較佳為0~0.1，更佳為0.001~0.08，進而較佳為0.005~0.08，進一步較佳為0.01~0.075，更進一步較佳為0.01~0.07之範圍。另一方面，於更加重視耐失透性之情形時，莫耳比B2 O3 /(SiO2 +Al2 O3 )為0~0.12，較佳為0.01~0.10，更佳為0.02~0.09，進而較佳為0.025~0.085之範圍。再者，關於上述莫耳比之倒數即(SiO2 +Al2 O3 )/B2 O3 ，於B2 O3 超過0 mol%之情形時，較佳為8.3以上。 B2 O3 與P2 O5 之合計量即B2 O3 +P2 O5 若過少，則會有熔解性降低之傾向，若過多，則會有B2 O3 +P2 O5 之玻璃之不均質變顯著，容易產生條紋，且應變點降低之傾向。因此，B2 O3 +P2 O5 較佳為0~8 mol%，更佳為0~5 mol%,，進而較佳為0.1~5 mol%，進一步較佳為1.5~5 mol%。另一方面，於重視耐失透性之情形時，B2 O3 +P2 O5 較佳為0~7 mol%，更佳為0.1~7 mol%，進而較佳為1~7 mol%，進一步較佳為1.5~7 mol%，更進一步較佳為1.5~6.5 mol%，進而進一步較佳為2~6.5 mol%，再進一步較佳為2~6 mol%之範圍。B2 O3 +P2 O5 係考慮熔解性與耐失透性之兩者而適當決定。若考慮熔解性與耐失透性之兩者，則B2 O3 +P2 O5 較佳為1~8 mol%，更佳為1.5~7 mol%，進而較佳為2~5 mol%。 莫耳比MgO/RO成為耐失透性之指標。其中，RO為MgO、CaO、SrO及BaO之含量之合計量(MgO+CaO+ SrO+BaO)。MgO/RO較佳為0.15~0.9，更佳為0.2~0.8，進而較佳為0.3~0.7，進一步較佳為0.3~0.6之範圍。藉由設為該等範圍，可兼顧耐失透性及熔解性。進而，可實現低密度化。 SrO及BaO係可降低玻璃之失透溫度之成分。其等並非必需成分，但若含有SrO及BaO，則耐失透性及熔解性提昇。但若含量過多，則密度上升。就上述觀點而言，SrO含量及BaO含量之合計量(SrO+BaO)較佳為0~15 mol%之範圍，更佳為0~10 mol%，進而較佳為0~7 mol%，進一步較佳為0~5 mol%，更進一步較佳為0~4 mol%，進而進一步較佳為0~3 mol%，再進一步較佳為0~2 mol%之範圍。於欲降低密度之情形時，較佳為實質上不含SrO及BaO。 MgO、CaO、SrO及BaO係提昇熔解性之成分。若MgO、CaO、SrO及BaO之含量之合計量即RO (MgO+CaO+ SrO+BaO)過少，則熔解性惡化。若RO過多，則應變點降低，密度上升，且楊氏模數降低。又，若RO過多，則亦會有熱膨脹係數增大之傾向。就上述觀點而言，RO較佳為4~25 mol%之範圍，更佳為7~21 mol%，進而較佳為12~19 mol%之範圍。 BaO係對環境之負荷較大之成分，且若其含量增多，則玻璃之密度提高，難以實現玻璃基板之輕量化。BaO/RO較佳為0~0.5，更佳為0~0.1，進而較佳為0~0.07，進一步較佳為0~0.05，更進一步較佳為0~0.02之範圍。 Li2 O、Na2 O及K2 O係提高玻璃之鹼性度，使澄清劑之氧化變容易而發揮澄清性之成分。又，其等係降低熔融溫度下之黏性，提昇熔解性之成分。又，其等亦係降低熔融玻璃之比電阻之成分。Li2 O、Na2 O及K2 O並非必需成分，但若含有該等，則熔融玻璃之比電阻降低，澄清性及熔解性提昇。尤其，可防止電流於構成熔解槽之耐火物中過度流通，可抑制熔解槽被侵蝕。又，於熔解槽含有氧化鋯之情形時，可抑制氧化鋯自熔解槽溶出至玻璃，故而亦可抑制由氧化鋯引起之失透。又，由於使熔解玻璃之黏性降低，故而熔解性及澄清性提昇。然而，若Li2 O、Na2 O及K2 O之含量之合計量即R2 O過多，則會有自玻璃基板溶出而使TFT特性劣化之虞。又，會有熱膨脹係數增大之傾向。R2 O較佳為0~0.8 mol%，更佳為0.01~0.5 mol%，進而較佳為0.1~0.3 mol%。 K2 O與Li2 O或Na2 O相比，分子量較大，故而不易自玻璃基板溶出。因此，於含有R2 O之情形時，較佳為相比Li2 O或Na2 O，更多地含有K2 O。若Li2 O及Na2 O之比率較大，則自玻璃基板溶出而使TFT特性劣化之虞變強。莫耳比K2 O/R2 O較佳為0.5~1，更佳為0.6~1，進而較佳為0.65~1，進一步較佳為0.7~1之範圍。 本發明之玻璃基板之失透溫度較佳為未達1280℃，更佳為1260℃以下，進而較佳為1250℃以下，進一步較佳為1235℃以下，更進一步較佳為1215℃以下。若失透溫度未達1280℃，則容易以溢流下拉法成形玻璃板。藉由應用溢流下拉法，可省略對玻璃基板表面進行研磨之步驟，故而可提昇玻璃基板之表面品質。又，亦可降低生產成本。若失透溫度過高，則會有容易產生失透，品質降低之虞。又，會有難以應用於溢流下拉法之傾向。 本發明之玻璃基板於100℃~300℃下之平均熱膨脹係數(100-300℃)較佳為28×10-7 ℃-1 以上且未達50×10-7 ℃-1 ，較佳為未達41×10-7 ℃-1 ，更佳為28×10-7 ℃-1 ~未達41×10-7 ℃-1 ，進而較佳為28×10-7 ℃-1 ~未達39×10-7 ℃-1 ，進一步較佳為28×10-7 ℃-1 ~未達38×10-7 ℃-1 ，更進一步較佳為32×10-7 ℃-1 ~未達38×10-7 ℃-1 ，進而進一步較佳為超過34×10-7 ℃-1 ~未達38×10-7 ℃-1 之範圍。若熱膨脹係數較大，則於熱處理步驟中，會有熱衝擊或熱收縮率增大之傾向。於LTPS-TFT之製造步驟中，反覆進行急加熱及急冷，對玻璃基板之熱衝擊增大。進而，大型之玻璃基板於熱處理步驟中容易產生溫度差(溫度分佈)，玻璃基板之破壞概率變高。又，若熱膨脹係數較大，則難以降低熱收縮率。另一方面，若熱膨脹係數較小，則會有難以獲得形成於玻璃基板上之金屬、有機系接著劑等周邊材料與熱膨脹係數之匹配，而導致周邊構件剝離之虞。 一般而言，若玻璃基板應變點較低，則於製造顯示器時之熱處理步驟中容易產生熱收縮。本發明之玻璃基板之應變點較佳為670℃以上，更佳為680℃以上，進而較佳為685℃以上，進一步較佳為690℃以上，更進一步較佳為695℃以上。 本發明之玻璃基板之熱收縮率為未達75 ppm，較佳為未達70 ppm，更佳為未達65 ppm，更佳為未達60 ppm。熱收縮率較佳為55 ppm以下，進而較佳為50 ppm以下，進一步較佳為48 ppm以下，更進一步較佳為45 ppm以下。若熱收縮率(量)過大，則會引起像素之較大之間距偏差，無法實現高精細之顯示器。為了將熱收縮率(量)控制在特定範圍內，較佳為將玻璃基板之應變點設為670℃以上，且將平均熱膨脹係數(100-300℃)設為未達50×10-7 ℃-1 。再者，熱收縮率最佳為0 ppm，若欲使熱收縮率為0 ppm，則需要極其延長緩冷卻步驟，或於緩冷卻、切割步驟後實施熱收縮降低處理(離線緩冷卻)，於此情形時，生產性降低，且成本高漲。若鑒於生產性及成本，則熱收縮率例如較佳為3 ppm以上且未達75 ppm，更佳為5 ppm以上且未達75 ppm，進而較佳為10 ppm以上且未達65 ppm，進一步較佳為15 ppm以上且未達60 ppm，更進一步較佳為20~55 ppm，進而進一步較佳為25~50 ppm。 再者，熱收縮率係以實施升降溫速度為10℃/min、以550℃保持2小時之熱處理後之下述式表示。更詳細而言，自常溫以10℃/min升溫，以550℃保持2小時，其後，以10℃/min降溫至常溫。 熱收縮率(ppm)={熱處理前後之玻璃之收縮量/熱處理前之玻璃之長度}×106 此時，所謂「熱收縮處理前後之玻璃之收縮量」係指「熱處理前之玻璃之長度-熱處理後之玻璃之長度」。 就玻璃基板之輕量化及顯示器之輕量化之觀點而言，本發明之玻璃基板之密度較佳為2.6 g/cm3 以下，更佳為2.57 g/cm3 以下，進而較佳為2.53 g/cm3 以下，進一步較佳為2.5 g/cm3 以下。若密度過高，則玻璃基板之輕量化變得困難，亦無法實現顯示器之輕量化。 若玻璃之轉移點(以下記作Tg)降低，則會有耐熱性降低之傾向。又，亦會有於熱處理步驟中容易產生熱收縮之傾向。本發明之玻璃基板之Tg較佳為720℃以上，更佳為730℃以上，進而較佳為740℃以上，進一步較佳為750℃以上。為了將玻璃基板之Tg設為上述範圍，較適當為於本發明之玻璃基板之組成之範圍中，增加提高Tg之成分，例如SiO2 及Al2 O3 等成分，或減少B2 O3 成分。 構成本發明之玻璃基板之玻璃較佳為蝕刻速率為50 μm/h以上。若蝕刻速率變快，則生產性提昇。尤其，於貼合TFT側與彩色濾光片側之玻璃基板之後進行蝕刻，並謀求輕量化之情形時，蝕刻速率會影響生產性。然而，若蝕刻速率過高，則雖液晶製造時之生產性提昇，但玻璃之耐失透性降低。又，熱收縮率亦變得容易增大。蝕刻速率較佳為60~140 μm/h，更佳為70~120 μm/h，進而較佳為75~120 μm/h，進一步較佳為80~120 μm/h。為了提高玻璃之蝕刻速率，只要減小SiO2 -Al2 O3 /2之值即可。另一方面，為了降低玻璃之蝕刻速率，例如只要增大SiO2 -Al2 O3 /2之值即可。於本發明中，上述蝕刻速率係定義為於以下條件下測定而得者。蝕刻速率(μm/h)係表示為將玻璃基板於調整為HF濃度1 mol/kg、HCl濃度5 mol/kg之40℃之蝕刻液中浸漬1小時之情形時之每單位時間(1小時)之玻璃基板之一表面的厚度減少量(μm)。 本發明之玻璃基板板厚例如可為0.1~1.1 mm之範圍。但並不意圖限於此範圍。板厚例如亦可為0.1~0.7 mm、0.3~0.7 mm、0.3~0.5 mm之範圍。若玻璃板之厚度過薄，則玻璃基板本身之強度降低。例如，於製造平面面板顯示器時容易產生破損。若板厚過厚，則對需求薄型化之顯示器而言欠佳。又，由於玻璃基板之重量變重，故而難以實現平面面板顯示器之輕量化。進而，於在形成TFT後進行蝕刻處理之情形時，蝕刻處理量增多，耗費成本及時間。 本發明之玻璃基板例如用於製造於貼合陣列-彩色濾光片後對玻璃基板表面進行蝕刻處理之平面面板顯示器。尤其，本發明之玻璃基板適於形成有LTPS-TFT或OS-TFT之平面面板顯示器用玻璃基板。具體而言，適於液晶顯示器用玻璃基板、有機EL顯示器用玻璃基板。尤其，適於LTPS-TFT液晶顯示器用玻璃基板、LTPS-TFT有機EL顯示器用玻璃基板。其中，適於需求高精細之移動終端等之顯示器用玻璃基板。 ＜平面面板顯示器＞ 本發明包含於玻璃基板表面形成有LTPS-TFT或OS-TFT之平面面板顯示器，該平面面板顯示器之玻璃基板為上述本發明之玻璃基板。本發明之平面面板顯示器例如可為液晶顯示器或有機EL顯示器。 ＜玻璃基板之製造方法＞ 本發明之平面面板顯示器用玻璃基板之製造方法包括以下步驟： 熔解步驟，其將調合成特定組成之玻璃原料例如使用直接通電加熱或燃燒加熱進行熔解； 成形步驟，其將上述熔解步驟中熔解而成之熔融玻璃成形為平板狀玻璃；及 緩冷卻步驟，其對上述平板狀玻璃進行緩冷卻。 尤其，上述緩冷卻步驟較佳為控制上述平板狀玻璃之冷卻條件以降低上述平板狀玻璃之熱收縮率之步驟。 [熔解步驟] 於熔解步驟中，將以具有特定組成之方式進行調合之玻璃原料例如使用直接通電加熱或燃燒加熱進行熔解。玻璃原料可自公知之材料適當選擇。就能效之觀點而言，於熔解步驟中，較佳為至少使用直接通電加熱將玻璃原料熔解。又，進行熔解步驟之熔解槽較佳為含有高氧化鋯系耐火物而構成。 [成形步驟] 於成形步驟中，將熔解步驟中熔解而成之熔融玻璃成形為平板狀玻璃。對平板狀玻璃之成形方法例如較佳為下拉法，尤佳為溢流下拉法，且成形玻璃帶作為平板狀玻璃。此外，可應用浮式法、再曳引法、輾平法等。藉由採用下拉法，與使用浮式法等其他成形方法之情形相比，所獲得之玻璃基板之主表面以與氣體氛圍以外不接觸之自由表面形成，故而具有極高之平滑性，無需成形後之玻璃基板表面之研磨步驟，故而可降低製造成本，進而亦可提昇生產性。進而，使用下拉法而成形之玻璃基板之兩主表面具有均勻之組成，故而於進行蝕刻處理時，可無關於成型時之表面背面而均勻地進行蝕刻。而且，藉由使用下拉法而成形，可獲得具有無由玻璃基板表面之研磨步驟引起之微裂痕之表面狀態的玻璃基板，故而亦可提昇玻璃基板本身之強度。 [緩冷卻步驟] 可藉由適當調整緩冷卻時之條件而控制玻璃基板之熱收縮率。尤佳為以降低上述平板狀玻璃之熱收縮率之方式控制上述平板狀玻璃之冷卻條件。玻璃基板之熱收縮率如上所述為3 ppm以上且未達75 ppm。為了製造3 ppm以上且未達75 ppm之玻璃基板，例如於使用下拉法之情形時，較理想為將作為平板狀玻璃之玻璃帶之溫度耗費20~200秒鐘於Tg至Tg-100℃之溫度範圍內進行冷卻，以此方式進行成形。若未達20秒鐘，則會有無法充分降低熱收縮率之情形。另一方面，若超過200秒鐘，則生產性降低，並且使玻璃製造裝置(緩冷卻爐)大型化。或者，較佳為以將作為平板狀玻璃之玻璃帶之冷卻速度於Tg至Tg-100℃之溫度範圍內設為30~300℃/min之方式進行緩冷卻。若冷卻速度超過300℃/min，則會有無法充分降低熱收縮率之情形。另一方面，若未達30℃/min，則生產性降低，並且使玻璃製造裝置(緩冷卻爐)大型化。冷卻速度之較佳之範圍為30~300℃/min，更佳為50~200℃/min，進而較佳為60~120℃/min。再者，於在緩冷卻步驟之下游切割平板狀玻璃之後，亦可藉由另外離線地進行緩冷卻而降低熱收縮率，但於此情形時，除進行緩冷卻步驟之設備外，必需另外離線地進行緩冷卻之設備。因此，就生產性及成本之觀點而言，較佳為如上所述以可降低熱收縮率之方式對緩冷卻步驟進行控制，從而可省略離線緩冷卻。 [實施例] 以下，基於實施例進而詳細地說明本發明。但本發明並不限於實施例。 實施例1~34 以成為表1所示之玻璃組成之方式，根據以下程序製作實施例1~34及參考例1~4之試樣玻璃。對所獲得之試樣玻璃及試樣玻璃基板求出失透溫度、Tg、100~300℃之範圍之平均熱膨脹係數、熱收縮率、密度、應變點。 [表1] (試樣玻璃之製作) 首先，使用作為通常之玻璃原料之二氧化矽、氧化鋁、氧化硼、碳酸鉀、鹼性碳酸鎂、碳酸鈣、硝酸鍶、硝酸鋇、二氧化矽及三氧化二鐵，以成為表1所示之玻璃組成之方式調合玻璃原料配料(以下稱作配料)。再者，以於玻璃中成為400 g之量進行調合。 上述調合之配料係於鉑坩堝中熔融及澄清。首先，將該坩堝於設定為1600℃之電爐中保持3小時而熔融配料。繼而，藉由將該電爐升溫至1640℃並保持4小時而進行玻璃熔融液之澄清。其後，使玻璃熔融液於爐外流出至鐵板上，進行冷卻固化而獲得玻璃體。對該玻璃體繼續實施緩冷卻操作。緩冷卻操作係藉由如下方式進行：將該玻璃體於設定為800℃之另一電爐中保持2小時之後，以2小時冷卻至740℃，進而以2小時冷卻至660℃後，切斷該電爐之電源，並冷卻至室溫。將經過該緩冷卻操作之玻璃體作為試樣玻璃。上述試樣玻璃係用於不受緩冷卻條件影響，且/或無法以基板狀測定之特性(失透溫度、熱膨脹係數、Tg及應變點)之測定。 對上述試樣玻璃實施切割、研削及研磨加工而製成為5 mm、長度為20 mm之圓柱狀，並將其以Tg保持30分鐘之後，以100℃/min冷卻至Tg-100℃，並冷卻至室溫，藉此製作熱收縮測定用試樣玻璃。 (應變點) 將上述試樣玻璃切割、研削加工為3 mm見方、長度為55 mm之角柱形狀而製作試驗片。使用彎樑測定裝置(東京工業股份有限公司製造)對該試驗片進行測定，並根據彎樑法(ASTM(American Society for Testing and Materials，美國材料試驗協會) C-598)藉由計算求出應變點。 (熱收縮率) 熱收縮率係使用以10℃/min自常溫升溫並以550℃保持2小時，其後，以10℃/min降溫至常溫後之熱收縮測定用試樣玻璃之收縮量藉由下式求出。 熱收縮率(ppm)={熱處理前後之玻璃之收縮量/熱處理前之玻璃之長度}×106 (失透溫度之測定方法) 將上述試樣玻璃粉碎，通過2380 μm之篩，獲得殘留在1000 μm之篩上之玻璃粒。將該玻璃粒浸漬於乙醇中並進行超音波清洗之後，使其於恆溫槽中乾燥。將經乾燥之玻璃粒放入寬度為12 mm、長度為200 mm、深度為10 mm之鉑坩堝上，以使25 g之上述玻璃粒成為大致固定之厚度。將該鉑坩堝於具有1080~1400℃之溫度梯度之電爐內保持5小時，其後，自爐中取出，並利用50倍之光學顯微鏡觀察玻璃內部所產生之失透。將觀察到失透之最高溫度設為失透溫度。 (100~300℃之範圍內之平均熱膨脹係數α及Tg之測定方法) 將上述試樣玻璃加工成為5 mm、長度為20 mm之圓柱狀而製作試驗片。使用示差熱膨脹計(Thermo Plus2 TMA8310)對該試驗片測定升溫過程中之溫度及試驗片之伸縮量。此時之升溫速度係設為5℃/min。以上述溫度及試驗片之伸縮量之測定結果為基礎，求出100~300℃之溫度範圍內之平均熱膨脹係數及Tg。再者，本案中之所謂Tg係指對將玻璃體於設定為800℃之另一電爐中保持2小時之後，以2小時冷卻至740℃，進而以2小時冷卻至660℃後，切斷該電爐之電源並冷卻至室溫之試樣玻璃進行測定而得之值。 (密度) 玻璃之密度係藉由阿基米德法進行測定。 (蝕刻速率) 蝕刻速率(μm/h)係表示為將試樣玻璃(12.5 mm×20 mm×0.7 mm)於以HF濃度成為1 mol/kg、HCl濃度成為5 mol/kg之方式製備而成之40℃之蝕刻液(200 ml)中浸漬1小時之情形時之每單位時間(1小時)之玻璃基板之一表面的厚度減少量(μm)。 使用具有包含高氧化鋯系耐火物之耐火磚製造之熔解槽及鉑合金製造之製備槽之連續熔解裝置將以成為實施例所示之組成之方式調合之玻璃原料以1560~1640℃進行熔解，且以1620~1670℃澄清並以1440~1530℃攪拌之後，藉由溢流下拉法成形為厚度為0.7 mm之薄板狀，並自Tg至Tg-100℃之溫度範圍內，以100℃/min之速度進行緩冷卻，從而獲得玻璃基板。再者，關於上述記載之各特性係使用所獲得之玻璃基板進行測定。再者，熱收縮率係藉由下述方法求出。 於玻璃基板之特定位置標註直線狀之標記之後，對該玻璃基板相對於標記垂直地添加切割線，而分割為2片玻璃板片。繼而，僅對一片玻璃板片實施550℃、2小時之熱處理。其後，將實施有熱處理之玻璃板片與未處理之玻璃板片並列並以黏著帶固定後，測定標記之偏移，以下述式求出熱收縮率。 熱收縮率(ppm)={熱處理前後之玻璃之收縮量/熱處理前之玻璃之長度}×106 以上述方式獲得之玻璃熱收縮率為3 ppm以上且未達75 ppm。又，失透溫度亦未達1280℃。因此，藉由使用該等玻璃，利用溢流下拉法，能製造可用於應用有LTPS-TFT之顯示器之玻璃基板。又，該等玻璃基板亦適用作OS-TFT用玻璃基板。The glass substrate for a flat panel display of the present invention is expressed in mol% and contains: 55 to 80% of SiO 2 , 8~20% Al 2 O 3 , 0~8% of B 2 O 3 , more than 0% to 15% of MgO, 0 to 20% of CaO, 0 to 15% of SrO, 0 to 10% of BaO; and SiO 2 +2×Al 2 O 3 100% or less; Mobi B 2 O 3 /(SiO 2 +Al 2 O 3 ) is 0 to 0.12; Mohr is MgO/RO (where RO is the total amount of MgO, CaO, Sr0, and BaO) in the range of 0.15 to 0.9; the devitrification temperature is less than 1280 ° C; and 10 ° C/min from the normal temperature. The temperature was raised and maintained at 550 ° C for 2 hours, and thereafter, after the temperature was lowered to 10 ° C / min to room temperature, the heat shrinkage ratio represented by the following formula was 3 ppm or more and less than 75 ppm. Heat shrinkage rate (ppm) = {shrinkage of glass before and after heat treatment / length of glass before heat treatment} × 10 6 Hereinafter, a glass substrate for a flat panel display of the present invention will be described. SiO 2 It is a skeleton component of glass and is therefore an essential component. If the content is decreased, the acid resistance is lowered, the strain point is lowered, and the coefficient of thermal expansion tends to increase. Also, if SiO 2 When the content is too small, it is difficult to reduce the density of the glass substrate. On the other hand, if SiO 2 When the content is too large, the melt viscosity is remarkably increased and it tends to be difficult to melt. If SiO 2 If the content is too much, there is a tendency for the resistance to devitrification to decrease. SiO 2 The content is set in the range of 55 to 80 mol%. SiO 2 The content is preferably 60 to 75 mol%, more preferably 62 to 73 mol%, still more preferably 63 to 72 mol%, still more preferably 63 to 70 mol%, still more preferably 65 to 70 mol%. Further, it is further preferably 65 to 69 mol%, and still more preferably 65 to 68 mol%. Al 2 O 3 It is necessary to suppress the phase separation and increase the strain point. If Al 2 O 3 When the content is too small, the glass becomes easy to separate. Also, if Al 2 O 3 If the content is too small, the strain point is lowered. Further, if Al 2 O 3 If the content is too small, the Young's modulus will also decrease, depending on the tendency of the acid etching rate to decrease. If Al 2 O 3 When the content is too large, the devitrification temperature of the glass increases and the devitrification resistance decreases, so that the formability tends to be deteriorated. In view of the above, Al 2 O 3 The content is in the range of 8 to 20 mol%. Al 2 O 3 The content is preferably from 8 to 18 mol%, more preferably from 9 to 17 mol%, still more preferably from 11 to 15 mol%, still more preferably from 12 to 15 mol%, still more preferably from 12 to 14 mol%. The scope. B 2 O 3 It is a component that lowers the high temperature viscosity of glass and improves the meltability. That is, since the viscosity in the vicinity of the melting temperature is lowered, the meltability can be improved. Also, B 2 O 3 It is also a component that reduces the devitrification temperature. If B 2 O 3 When the content is small, the meltability is lowered and the resistance to devitrification is lowered. If B 2 O 3 If the content is too large, the strain point is lowered and the heat resistance is lowered. Also, if B 2 O 3 If the content is too much, the Young's modulus is lowered. Also, when B is formed by glass 2 O 3 It volatilizes and is prone to devitrification. In particular, since the glass having a high strain point tends to have a high forming temperature, the above-described volatilization is promoted, and the occurrence of devitrification becomes a significant problem. Also, when B is melted by glass 2 O 3 The volatilization, the inhomogeneity of the glass becomes remarkable, and streaks are easily generated. In view of the above, B 2 O 3 The content is 0 to 8 mol%, preferably 0 to 5 mol%. B 2 O 3 The content is preferably from 0.1 to 5 mol%, more preferably from 1.5 to 5 mol%, still more preferably from 1.5 to 4.5 mol%. On the other hand, when attaching importance to the situation of devitrification resistance, B 2 O 3 The content is preferably 0 to 7 mol%, more preferably 0.1 to 7 mol%, still more preferably 1 to 7 mol%, still more preferably 1.5 to 7 mol%, still more preferably 1.5 to 6.5 mol%, Further, it is further preferably in the range of 2 to 6 mol%. B 2 O 3 The content is appropriately determined in consideration of both the meltability and the resistance to devitrification. If considering both meltability and resistance to devitrification, then B 2 O 3 The content is preferably from 1 to 5 mol%, more preferably from 1.5 to 5 mol%, still more preferably from 1.5 to 4.5 mol%. MgO is an essential component for improving the meltability. Further, since it is a component which is less likely to increase the density in the alkaline earth metal, if the content is relatively increased, the density is easily lowered. The meltability can be improved by containing MgO. However, if the content of MgO is too large, the devitrification temperature of the glass rises sharply, so that it is particularly devitrified in the molding step. Further, when the content of MgO is too large, the acid resistance tends to decrease. From the above viewpoints, the MgO content is more than 0 mol% to 15 mol%, preferably 1.5 to 15 mol%, more preferably 2 to 15 mol%, still more preferably 2 to 12 mol%, further preferably 3 to 11 mol%, more preferably 4 to 10 mol%, still more preferably 5 to 9 mol%. The CaO system is an effective component for improving the devitrification temperature of the glass without increasing the devitrification temperature of the glass. Further, since it is a component which is less likely to increase the density in the alkaline earth metal, if the content is relatively increased, the density is easily lowered. If the content is too small, there is a tendency for the resistance to devitrification to decrease. If the CaO content is too large, the coefficient of thermal expansion increases and the density tends to increase. From the above viewpoints, the CaO content is 0 to 20 mol%, preferably 3 to 15 mol%, more preferably 4 to 13 mol%, still more preferably 5 to 11 mol%, still more preferably 7 to 11 mol%. The range of mol%. The SrO system reduces the composition of the devitrification temperature of the glass. SrO is not essential, but if it contains SrO, resistance to devitrification and melting are improved. However, if the SrO content is too large, the density will increase. From the above viewpoints, the SrO content is 0 to 15 mol%, preferably 0 to 10 mol%, more preferably 0 to 7 mol%, still more preferably 0 to 4 mol%, still more preferably 0 to 2 The mol% is more preferably 0 to 1.5 mol%, and still more preferably 0 to 1 mol%. In the case where the density of the glass is to be lowered, it is preferably substantially free of SrO. BaO reduces the composition of the devitrification temperature of the glass. It is not an essential component, but if BaO is contained, devitrification resistance and meltability are improved. However, if the content of BaO is too large, the density will increase. Further, in the case of the environmental load and the tendency to increase the coefficient of thermal expansion, the BaO content is 0 to 10 mol%, preferably 0 to 4 mol%, more preferably 0 to 3 mol%, and further Preferably, it is 0 to 2.5 mol%, further preferably 0 to 2 mol%, still more preferably 0 to 1 mol%, still more preferably 0 to 0.5 mol%, still more preferably substantially free of BaO. . Li 2 O and Na 2 The O system has a component which is eluted from the glass substrate to deteriorate the TFT characteristics, or which increases the thermal expansion coefficient of the glass and damages the substrate during the heat treatment. Preferably, substantially no Li is contained 2 O and Na 2 O. K 2 O is a component that increases the alkalinity of the glass and promotes clarification. Further, it improves the meltability and lowers the specific resistance of the molten glass. It is not an essential ingredient, but if it contains K 2 O, the specific resistance of the molten glass is lowered, and current can be prevented from flowing in the refractory constituting the melting tank, and the melting tank can be prevented from being eroded. Further, when the refractory material constituting the melting tank contains zirconia, it is possible to suppress the erosion of the melting tank and cause the zirconia to be eluted from the melting tank to the glass, so that devitrification caused by zirconia can be suppressed. Further, since the viscosity of the glass in the vicinity of the melting temperature is lowered, the meltability and the clarification property are improved. On the other hand, if K 2 When the content of O is too large, there is a possibility that the characteristics of the TFT are deteriorated by elution from the glass substrate. Moreover, there is a tendency that the coefficient of thermal expansion also increases. In view of the above, K 2 The O content is preferably from 0 to 0.8 mol%, more preferably from 0.01 to 0.5 mol%, still more preferably from 0.1 to 0.3 mol%. ZrO 2 And TiO 2 It is a component that increases the chemical durability and strain point of glass. ZrO 2 And TiO 2 Not an essential ingredient, but by containing ZrO 2 And TiO 2 It can increase the strain point and improve the acid resistance. However, if ZrO 2 Amount and TiO 2 If the amount is too large, the devitrification temperature is remarkably increased, so that the devitrification resistance and the formability are lowered. Especially ZrO 2 The melting point is high and refractory, so that one of the raw materials is deposited on the bottom of the melting furnace. When these unmelted components are mixed into the glass green body, the quality of the glass is deteriorated as an inclusion. Also, TiO 2 Since the glass is colored, it is not preferable for the substrate for display. In view of the above, in the glass substrate of the present invention, ZrO 2 And TiO 2 The content ratio is preferably 0 to 5 mol%, more preferably 0 to 3 mol%, still more preferably 0 to 2 mol%, still more preferably 0 to 1 mol%. Further preferably, the glass substrate of the present invention is substantially free of ZrO 2 And TiO 2 . ZnO is a component that enhances BHF (Buffered Hydrofluoric Acid) or meltability. But it is not an essential ingredient. When the ZnO content is too large, the devitrification temperature rises, the strain point decreases, and the density tends to increase. From the above viewpoints, the ZnO content is preferably from 0 to 5 mol%, more preferably from 0 to 3 mol%, still more preferably from 0 to 2 mol%, still more preferably from 0 to 1 mol%. It is preferably substantially free of ZnO. P 2 O 5 It is a component that lowers the viscosity of high temperature and enhances the melting property. But it is not an essential ingredient. If P 2 O 5 If the content is too much, the P is melted by the glass. 2 O 5 The volatilization, the inhomogeneity of the glass becomes remarkable, and streaks are easily generated. Also, the acid resistance is significantly deteriorated. Also, it is easy to produce milky white. In view of the above, P 2 O 5 The content is preferably 0 to 3 mol%, more preferably 0 to 1 mol%, further preferably 0 to 0.5 mol%, and particularly preferably substantially no P. 2 O 5 . The glass substrate of the present invention may contain a clarifying agent. The clarifying agent is not particularly limited as long as it has a small load on the environment and is excellent in clarity of the glass, and examples thereof include a group of metal oxides selected from the group consisting of Sn, Fe, Ce, Tb, Mo, Sb, and W. At least one of them. As a clarifying agent, preferably SnO 2 . When the content of the clarifying agent is too small, the quality of the bubbles is deteriorated, and if the content is too large, the film may be devitrified or colored. The amount of clarifying agent also depends on the type of clarifying agent or the composition of the glass. For example, SnO 2 , Fe 2 O 3 And Sb 2 O 3 The total amount is preferably 0.05 to 0.20 mol%. SnO 2 A clarifying agent capable of obtaining a clarifying effect even at a temperature of 1600 ° C or higher, and can be used for a glass substrate for a flat panel display which can contain only a small amount of an alkali metal oxide (for example, the total amount of alkali metal oxides is 0 to 0.8 mol%) There are a few clarifying agents in the manufacture of). However, SnO 2 In order to easily cause devitrification, it is not preferable to add a large amount from the viewpoint of suppressing devitrification. Further, a glass having a higher strain point (for example, a glass having a strain point of 670 ° C or higher) tends to have a higher devitrification temperature than a glass having a lower strain point (for example, a glass having a strain point of less than 670 ° C). Therefore, in order to suppress devitrification, it is necessary to make the temperature of the molten glass in the forming step higher than that of the glass having a lower strain point. Here, from the viewpoint of resistance to latent heat and heat resistance, the molded body used in the overflow down-draw method preferably comprises a refractory containing zirconia. In the case where the overflow down-drawing method is employed as the molding method, if the temperature of the molten glass in the molding step is to be increased, it is necessary to increase the temperature of the molded body. However, when the temperature of the molded body becomes high, zirconia is eluted from the molded body, and the problem of devitrification of the zirconia tends to occur. Also, in particular, it contains more SnO. 2 For the glass, there will be SnO due to the zirconia. 2 The loss of transparency. Furthermore, a glass having a higher strain point (for example, a glass having a strain point of 670 ° C or higher) and a glass having a lower strain point (for example, a glass having a strain point of less than 670 ° C) tend to have a higher temperature of the molten glass raw material. The tendency. Here, the melting tank in which the melting step is performed is preferably composed of a high-zirconia-based refractory containing zirconia from the viewpoint of corrosion resistance. Further, from the viewpoint of energy efficiency, it is preferred to melt the glass raw material by a combination of electrofusion or electrofusion and other heating methods. However, when melting a glass having a high strain point and having only a small amount of an alkali metal oxide as described in the present invention, the specific resistance of the molten glass is large, so that current is easily generated in the high zirconia refractory. Flowing, the problem of zirconia dissolution into molten glass. If zirconia is dissolved, there will be devitrification of the above zirconia and SnO caused by zirconia. 2 The loss of transparency. That is, suppressing SnO caused by zirconia 2 From the viewpoint of devitrification, in the glass substrate of the present invention, more than 0.2 mol% contains SnO 2 The situation is also not good. In view of the above, SnO 2 The content is, for example, preferably in the range of 0.01 to 0.2 mol%, more preferably 0.03 to 0.15 mol%, still more preferably 0.05 to 0.12 mol%. Fe 2 O 3 In addition to having a function as a clarifying agent, it also reduces the specific resistance of the molten glass. Among the glasses having high viscosity at high temperature and having incompatibility, it is preferred to contain Fe in order to lower the specific resistance of the molten glass. 2 O 3 . However, if Fe 2 O 3 If the content is too much, the glass is colored and the transmittance is lowered. Therefore, Fe 2 O 3 The content is in the range of 0 to 0.1 mol%, preferably 0 to 0.05 mol%, more preferably 0.001 to 0.05 mol%, still more preferably 0.003 to 0.05 mol%, still more preferably 0.005 to 0.03 mol%. In the present invention, the clarifying agent is preferably a combination of SnO. 2 With Fe 2 O 3 . As far as the devitrification is concerned, it is not appropriate to contain SnO as described above. 2 . However, in order to sufficiently obtain a clarifying effect, it is necessary to contain a clarifying agent having a specific value or more. Therefore, by using SnO together 2 With Fe 2 O 3 Can make SnO 2 The content is not so much as to cause devitrification, and a sufficient clarifying effect is obtained to produce a glass substrate having less bubbles. SnO 2 With Fe 2 O 3 The total amount is preferably in the range of 0.05 to 0.2 mol%, more preferably 0.08 to 0.2 mol%, still more preferably 0.1 to 0.18 mol%, still more preferably 0.1 to 0.15 mol%. SnO 2 Content relative to SnO 2 With Fe 2 O 3 Total molar ratio (SnO 2 /(SnO 2 +Fe 2 O 3 )) If it is too large, it will easily cause devitrification. If it is too small, it will not be able to obtain sufficient clarification effect and the glass will be colored. Therefore, it is preferably in the range of 0.55 to 1, more preferably 0.6 to 1, further preferably 0.65 to 1, further preferably 0.65 to 0.95, still more preferably 0.65 to 0.9. The glass substrate of the present invention preferably contains substantially no As in terms of environmental load. 2 O 3 . The glass substrate of the present invention preferably contains 0 to 0.6 mol% of Sb in terms of environmental load. 2 O 3 More preferably 0 to 0.1 mol%, and most preferably substantially no Sb 2 O 3 . For reasons of environmental reasons, the glass substrate of the present invention preferably contains substantially no PbO and F. In the present specification, the term "substantially free" means that the raw material of the components is not used in the glass raw material, and the components contained in the glass raw material as impurities are not excluded from the other components. The manufacturing device is dissolved into the components of the glass. SiO 2 Content and Al 2 O 3 The total amount of 2 times is the SiO 2 +2×Al 2 O 3 If it is too small, the strain point tends to decrease, and if it is too large, the devitrification resistance tends to deteriorate. Therefore, SiO 2 +2×Al 2 O 3 It is 100 mol% or less, preferably 75 to 100 mol%, more preferably 75 to 97 mol%, still more preferably 80 to 96 mol%, still more preferably 85 to 96 mol%, still more preferably 85 to 95. Mol% is further preferably 87 to 95 mol%, further preferably 89 to 95 mol%, still more preferably 89 to 94 mol%. About SiO 2 Content and Al 2 O 3 1/2 difference SiO 2 -Al 2 O 3 /2, if the value is too small, the etching rate is increased, but the resistance to devitrification is lowered. If the value is too high, there will be a drop in the etch rate. From the above point of view, SiO 2 -Al 2 O 3 /2 is preferably 69 mol% or less, preferably 45 to 69 mol%, more preferably 45 to 64 mol%, still more preferably 50 to 63 mol%, still more preferably 55 to 62 mol%, further It is preferably 55 to 61.5 mol%, and further preferably 55 to 61 mol%. Moerby B 2 O 3 /(SiO 2 +Al 2 O 3 It is mainly an indicator of strain point and resistance to devitrification. As mentioned above, if B 2 O 3 When the content is small, the meltability and the resistance to devitrification are lowered. On the other hand, when the content is increased, the strain point is lowered and the heat resistance is lowered. Moreover, when the content is increased, the acid resistance and the Young's modulus tend to decrease. About B 2 O 3 /(SiO 2 +Al 2 O 3 ) There is basically the same tendency. Therefore, Moerby B 2 O 3 /(SiO 2 +Al 2 O 3 ) is set to the range of 0 to 0.12. If B 2 O 3 /(SiO 2 +Al 2 O 3 When it exceeds 0.12, the strain point may not be sufficiently increased, and the devitrification resistance tends to decrease to near 0. Moerby B 2 O 3 /(SiO 2 +Al 2 O 3 It is preferably 0 to 0.1, more preferably 0.001 to 0.08, still more preferably 0.005 to 0.08, still more preferably 0.01 to 0.075, still more preferably 0.01 to 0.07. On the other hand, when more emphasis is placed on the resistance to devitrification, Moerby B 2 O 3 /(SiO 2 +Al 2 O 3 It is 0 to 0.12, preferably 0.01 to 0.10, more preferably 0.02 to 0.09, still more preferably 0.025 to 0.085. Furthermore, regarding the reciprocal of the above molar ratio (ie, SiO 2 +Al 2 O 3 )/B 2 O 3 , in B 2 O 3 When it exceeds 0 mol%, it is preferably 8.3 or more. B 2 O 3 With P 2 O 5 Total measurement is B 2 O 3 +P 2 O 5 If it is too small, there will be a tendency for the meltability to decrease. If it is too much, there will be B. 2 O 3 +P 2 O 5 The unevenness of the glass becomes remarkable, and streaks are liable to occur, and the strain point tends to decrease. Therefore, B 2 O 3 +P 2 O 5 It is preferably 0 to 8 mol%, more preferably 0 to 5 mol%, still more preferably 0.1 to 5 mol%, still more preferably 1.5 to 5 mol%. On the other hand, when attaching importance to the situation of devitrification resistance, B 2 O 3 +P 2 O 5 It is preferably 0 to 7 mol%, more preferably 0.1 to 7 mol%, still more preferably 1 to 7 mol%, still more preferably 1.5 to 7 mol%, still more preferably 1.5 to 6.5 mol%, and further Further preferably, it is 2 to 6.5 mol%, and further preferably it is in the range of 2 to 6 mol%. B 2 O 3 +P 2 O 5 It is appropriately determined in consideration of both the meltability and the resistance to devitrification. If considering both meltability and devitrification resistance, then B 2 O 3 +P 2 O 5 It is preferably from 1 to 8 mol%, more preferably from 1.5 to 7 mol%, still more preferably from 2 to 5 mol%. Moerby MgO/RO is an indicator of resistance to devitrification. Among them, RO is a total amount of MgO, CaO, SrO, and BaO (MgO+CaO+SrO+BaO). The MgO/RO is preferably from 0.15 to 0.9, more preferably from 0.2 to 0.8, still more preferably from 0.3 to 0.7, still more preferably from 0.3 to 0.6. By setting these ranges, it is possible to achieve both devitrification resistance and meltability. Further, it is possible to achieve a low density. SrO and BaO systems reduce the composition of the devitrification temperature of the glass. These are not essential components, but when SrO and BaO are contained, devitrification resistance and meltability are improved. However, if the content is too much, the density increases. From the above viewpoints, the total amount of SrO content and BaO content (SrO+BaO) is preferably in the range of 0 to 15 mol%, more preferably 0 to 10 mol%, still more preferably 0 to 7 mol%, further It is preferably 0 to 5 mol%, still more preferably 0 to 4 mol%, still more preferably 0 to 3 mol%, still more preferably 0 to 2 mol%. In the case where the density is to be lowered, it is preferably substantially free of SrO and BaO. MgO, CaO, SrO and BaO enhance the melting properties. When the total content of MgO, CaO, SrO, and BaO, that is, RO (MgO + CaO + SrO + BaO) is too small, the meltability is deteriorated. If the RO is too large, the strain point is lowered, the density is increased, and the Young's modulus is lowered. Moreover, if the RO is too large, the thermal expansion coefficient tends to increase. From the above viewpoints, RO is preferably in the range of 4 to 25 mol%, more preferably 7 to 21 mol%, still more preferably 12 to 19 mol%. BaO is a component that has a large load on the environment, and if the content thereof is increased, the density of the glass is increased, and it is difficult to reduce the weight of the glass substrate. BaO/RO is preferably 0 to 0.5, more preferably 0 to 0.1, still more preferably 0 to 0.07, still more preferably 0 to 0.05, still more preferably 0 to 0.02. Li 2 O, Na 2 O and K 2 O is a component which increases the basicity of the glass and makes the oxidation of the clarifying agent easy to exhibit clarification. Further, it is a component which lowers the viscosity at the melting temperature and enhances the meltability. Further, these are also components which lower the specific resistance of the molten glass. Li 2 O, Na 2 O and K 2 O is not an essential component, but if it is contained, the specific resistance of the molten glass is lowered, and the clarifying property and the meltability are improved. In particular, it is possible to prevent current from flowing excessively in the refractory constituting the melting tank, and it is possible to suppress erosion of the melting tank. Further, when the melting bath contains zirconia, zirconia can be prevented from eluting from the melting tank to the glass, so that devitrification caused by zirconia can be suppressed. Further, since the viscosity of the molten glass is lowered, the meltability and the clarification property are improved. However, if Li 2 O, Na 2 O and K 2 The total content of O is R 2 When O is too large, there is a possibility that the characteristics of the TFT are deteriorated by elution from the glass substrate. Moreover, there is a tendency for the coefficient of thermal expansion to increase. R 2 O is preferably from 0 to 0.8 mol%, more preferably from 0.01 to 0.5 mol%, still more preferably from 0.1 to 0.3 mol%. K 2 O and Li 2 O or Na 2 Compared with O, the molecular weight is large, so it is not easily eluted from the glass substrate. Therefore, in containing R 2 In the case of O, it is better to compare with Li 2 O or Na 2 O, more containing K 2 O. If Li 2 O and Na 2 When the ratio of O is large, it is eluted from the glass substrate to deteriorate the characteristics of the TFT. Moerby K 2 O/R 2 O is preferably from 0.5 to 1, more preferably from 0.6 to 1, further preferably from 0.65 to 1, further preferably from 0.7 to 1. The devitrification temperature of the glass substrate of the present invention is preferably less than 1280 ° C, more preferably 1260 ° C or less, further preferably 1250 ° C or less, further preferably 1235 ° C or less, and still more preferably 12 15 ° C or less. If the devitrification temperature is less than 1280 ° C, it is easy to form the glass sheet by the overflow down-draw method. By applying the overflow down-draw method, the step of polishing the surface of the glass substrate can be omitted, so that the surface quality of the glass substrate can be improved. In addition, production costs can also be reduced. If the devitrification temperature is too high, there is a tendency to cause devitrification and a decrease in quality. Moreover, there is a tendency that it is difficult to apply to the overflow down-draw method. The average thermal expansion coefficient (100-300 ° C) of the glass substrate of the present invention at 100 ° C to 300 ° C is preferably 28 × 10 -7 °C -1 Above and not up to 50×10 -7 °C -1 , preferably less than 41×10 -7 °C -1 More preferably 28×10 -7 °C -1 ~Under 41×10 -7 °C -1 And further preferably 28×10 -7 °C -1 ~Not up to 39×10 -7 °C -1 Further preferably 28×10 -7 °C -1 ~Unseen 38×10 -7 °C -1 Further, it is preferably 32×10 -7 °C -1 ~Unseen 38×10 -7 °C -1 Further preferably more than 34×10 -7 °C -1 ~Unseen 38×10 -7 °C -1 The scope. If the coefficient of thermal expansion is large, there is a tendency that the thermal shock or the heat shrinkage rate increases in the heat treatment step. In the manufacturing process of the LTPS-TFT, the rapid heating and rapid cooling are repeatedly performed, and the thermal shock to the glass substrate is increased. Further, in the large-sized glass substrate, a temperature difference (temperature distribution) is likely to occur in the heat treatment step, and the probability of destruction of the glass substrate is increased. Moreover, if the coefficient of thermal expansion is large, it is difficult to reduce the heat shrinkage rate. On the other hand, when the coefficient of thermal expansion is small, it is difficult to obtain a match between the peripheral material such as a metal or an organic binder formed on the glass substrate and the thermal expansion coefficient, and the peripheral member is peeled off. In general, if the strain point of the glass substrate is low, heat shrinkage easily occurs in the heat treatment step at the time of manufacturing the display. The strain point of the glass substrate of the present invention is preferably 670 ° C or higher, more preferably 680 ° C or higher, further preferably 685 ° C or higher, further preferably 690 ° C or higher, and still more preferably 695 ° C or higher. The glass substrate of the present invention has a heat shrinkage ratio of less than 75 ppm, preferably less than 70 ppm, more preferably less than 65 ppm, and even more preferably less than 60 ppm. The heat shrinkage ratio is preferably 55 ppm or less, more preferably 50 ppm or less, further preferably 48 ppm or less, and still more preferably 45 ppm or less. If the heat shrinkage rate (amount) is too large, a large deviation between pixels will be caused, and a high-definition display cannot be realized. In order to control the heat shrinkage rate (amount) within a specific range, it is preferred to set the strain point of the glass substrate to 670 ° C or higher, and to set the average thermal expansion coefficient (100 - 300 ° C) to less than 50 × 10 -7 °C -1 . Further, the heat shrinkage rate is preferably 0 ppm, and if the heat shrinkage ratio is 0 ppm, it is necessary to extremely extend the slow cooling step, or to perform the heat shrinkage reduction treatment (offline cooling) after the slow cooling and cutting steps. In this case, productivity is lowered and costs are high. In view of productivity and cost, the heat shrinkage ratio is, for example, preferably 3 ppm or more and less than 75 ppm, more preferably 5 ppm or more and less than 75 ppm, and further preferably 10 ppm or more and less than 65 ppm. It is preferably 15 ppm or more and less than 60 ppm, more preferably 20 to 55 ppm, and still more preferably 25 to 50 ppm. In addition, the heat shrinkage rate is represented by the following formula after heat treatment at a temperature rise and fall rate of 10 ° C / min and 550 ° C for 2 hours. More specifically, the temperature was raised from normal temperature at 10 ° C / min, and maintained at 550 ° C for 2 hours, and thereafter, the temperature was lowered to normal temperature at 10 ° C / min. Heat shrinkage rate (ppm) = {shrinkage of glass before and after heat treatment / length of glass before heat treatment} × 10 6 In this case, the "shrinkage amount of the glass before and after the heat shrinkage treatment" means "the length of the glass before the heat treatment - the length of the glass after the heat treatment". The glass substrate of the present invention preferably has a density of 2.6 g/cm from the viewpoint of weight reduction of the glass substrate and weight reduction of the display. 3 Below, more preferably 2.57 g/cm 3 Hereinafter, it is further preferably 2.53 g/cm. 3 Hereinafter, it is further preferably 2.5 g/cm. 3 the following. If the density is too high, the weight of the glass substrate becomes difficult, and the weight of the display cannot be achieved. When the transition point of the glass (hereinafter referred to as Tg) is lowered, the heat resistance tends to decrease. Further, there is a tendency that heat shrinkage easily occurs in the heat treatment step. The Tg of the glass substrate of the present invention is preferably 720 ° C or higher, more preferably 730 ° C or higher, further preferably 740 ° C or higher, and further preferably 750 ° C or higher. In order to set the Tg of the glass substrate to the above range, it is more appropriate to increase the component of the Tg, such as SiO, in the range of the composition of the glass substrate of the present invention. 2 And Al 2 O 3 Equal component, or reduce B 2 O 3 ingredient. The glass constituting the glass substrate of the present invention preferably has an etching rate of 50 μm/h or more. If the etching rate becomes faster, the productivity is improved. In particular, when the glass substrate on the TFT side and the color filter side is bonded and then etched, and the weight is reduced, the etching rate affects productivity. However, if the etching rate is too high, the productivity at the time of liquid crystal production is improved, but the devitrification resistance of the glass is lowered. Moreover, the heat shrinkage rate also becomes easy to increase. The etching rate is preferably 60 to 140 μm/h, more preferably 70 to 120 μm/h, still more preferably 75 to 120 μm/h, still more preferably 80 to 120 μm/h. In order to increase the etching rate of the glass, it is only necessary to reduce the SiO 2 -Al 2 O 3 The value of /2 can be. On the other hand, in order to reduce the etching rate of the glass, for example, only SiO is increased. 2 -Al 2 O 3 The value of /2 can be. In the present invention, the above etching rate is defined as being measured under the following conditions. The etching rate (μm/h) is expressed per unit time (1 hour) when the glass substrate is immersed in an etching solution adjusted to an HF concentration of 1 mol/kg and a HCl concentration of 5 mol/kg at 40 ° C for 1 hour. The thickness reduction (μm) of the surface of one of the glass substrates. The thickness of the glass substrate of the present invention may be, for example, in the range of 0.1 to 1.1 mm. However, it is not intended to be limited to this scope. The plate thickness may be, for example, in the range of 0.1 to 0.7 mm, 0.3 to 0.7 mm, and 0.3 to 0.5 mm. If the thickness of the glass plate is too thin, the strength of the glass substrate itself is lowered. For example, it is prone to breakage when manufacturing a flat panel display. If the thickness of the plate is too thick, it is not good for a display that is thinner in demand. Moreover, since the weight of the glass substrate becomes heavy, it is difficult to reduce the weight of the flat panel display. Further, in the case where the etching treatment is performed after the TFT is formed, the amount of etching treatment is increased, which is costly and time consuming. The glass substrate of the present invention is used, for example, for a flat panel display in which a surface of a glass substrate is etched after bonding an array-color filter. In particular, the glass substrate of the present invention is suitable for a glass substrate for a flat panel display in which an LTPS-TFT or an OS-TFT is formed. Specifically, it is suitable for a glass substrate for a liquid crystal display or a glass substrate for an organic EL display. In particular, it is suitable for a glass substrate for an LTPS-TFT liquid crystal display or a glass substrate for an LTPS-TFT organic EL display. Among them, it is suitable for a glass substrate for a display such as a mobile terminal that requires high precision. <Flat Panel Display> The present invention comprises a flat panel display in which an LTPS-TFT or an OS-TFT is formed on a surface of a glass substrate, and the glass substrate of the flat panel display is the above-described glass substrate of the present invention. The flat panel display of the present invention may be, for example, a liquid crystal display or an organic EL display. <Method for Producing Glass Substrate> The method for producing a glass substrate for a flat panel display according to the present invention includes the following steps: a melting step of melting a glass raw material tuned to a specific composition, for example, by direct electric heating or combustion heating; a forming step, The molten glass melted in the melting step is formed into a flat glass, and a slow cooling step is performed to slowly cool the flat glass. In particular, the slow cooling step is preferably a step of controlling the cooling conditions of the flat glass to reduce the heat shrinkage rate of the flat glass. [Melting Step] In the melting step, the glass raw material blended in such a manner as to have a specific composition is melted by, for example, direct electric heating or combustion heating. The glass raw material can be appropriately selected from known materials. From the viewpoint of efficacy, in the melting step, it is preferred to melt the glass raw material using at least direct electric heating. Further, the melting tank in which the melting step is carried out is preferably composed of a high zirconia-based refractory. [Molding Step] In the forming step, the molten glass obtained by melting in the melting step is formed into a flat glass. The method for forming the flat glass is, for example, preferably a down-draw method, and particularly preferably an overflow down-draw method, and the formed glass ribbon is used as a flat glass. In addition, a floating method, a re-drag method, a flat method, or the like can be applied. By using the down-draw method, the main surface of the obtained glass substrate is formed as a free surface which is not in contact with the gas atmosphere as compared with the case of using other forming methods such as a floating method, so that it has extremely high smoothness and does not need to be formed. The polishing step of the surface of the rear glass substrate can reduce the manufacturing cost and further improve the productivity. Further, since the two main surfaces of the glass substrate formed by the down-draw method have a uniform composition, etching can be performed uniformly regardless of the surface back surface during molding. Further, by forming by using the down-draw method, a glass substrate having a surface state free from microcracks caused by the polishing step on the surface of the glass substrate can be obtained, so that the strength of the glass substrate itself can be improved. [Slow cooling step] The heat shrinkage rate of the glass substrate can be controlled by appropriately adjusting the conditions at the time of slow cooling. It is particularly preferable to control the cooling conditions of the flat glass in such a manner as to lower the heat shrinkage rate of the flat glass. The heat shrinkage rate of the glass substrate is 3 ppm or more and less than 75 ppm as described above. In order to manufacture a glass substrate of 3 ppm or more and less than 75 ppm, for example, when a down-draw method is used, it is preferable to use a glass ribbon as a flat glass for 20 to 200 seconds at a temperature of Tg to Tg-100 ° C. The cooling is carried out in the temperature range, and shaping is performed in this manner. If it is less than 20 seconds, there is a case where the heat shrinkage rate cannot be sufficiently reduced. On the other hand, when it exceeds 200 second, productivity will fall, and a glass manufacturing apparatus (slow cooling furnace) enlarges. Alternatively, it is preferred to perform slow cooling so that the cooling rate of the glass ribbon as the flat glass is 30 to 300 ° C/min in a temperature range of Tg to Tg - 100 ° C. If the cooling rate exceeds 300 ° C / min, there is a case where the heat shrinkage rate cannot be sufficiently lowered. On the other hand, if it is less than 30 ° C / min, the productivity is lowered, and the glass manufacturing apparatus (slow cooling furnace) is enlarged. The cooling rate is preferably in the range of 30 to 300 ° C / min, more preferably 50 to 200 ° C / min, and further preferably 60 to 120 ° C / min. Furthermore, after the flat glass is cut downstream of the slow cooling step, the heat shrinkage rate may be lowered by further slow cooling off, but in this case, in addition to the device for performing the slow cooling step, it is necessary to additionally take off offline. Equipment for slow cooling. Therefore, from the viewpoint of productivity and cost, it is preferable to control the slow cooling step so as to reduce the heat shrinkage rate as described above, so that offline slow cooling can be omitted. [Examples] Hereinafter, the present invention will be described in detail based on examples. However, the invention is not limited to the embodiment. Examples 1 to 34 Sample glasses of Examples 1 to 34 and Reference Examples 1 to 4 were produced according to the following procedure in such a manner as to have the glass composition shown in Table 1. The devitrification temperature, Tg, and the average thermal expansion coefficient, heat shrinkage ratio, density, and strain point in the range of 100 to 300 ° C were determined for the obtained sample glass and sample glass substrate. [Table 1] (Preparation of sample glass) First, cerium oxide, aluminum oxide, boron oxide, potassium carbonate, basic magnesium carbonate, calcium carbonate, cerium nitrate, cerium nitrate, cerium oxide, and trioxide are used as usual glass raw materials. Iron, the glass raw material ingredients (hereinafter referred to as ingredients) were blended in such a manner as to be the composition of the glass shown in Table 1. Further, the blending was carried out in an amount of 400 g in the glass. The above blended ingredients are melted and clarified in a platinum crucible. First, the crucible was kept in an electric furnace set at 1600 ° C for 3 hours to melt the ingredients. Then, the glass melt was clarified by raising the temperature of the electric furnace to 1640 ° C for 4 hours. Thereafter, the glass melt was discharged to the iron plate outside the furnace, and cooled and solidified to obtain a glass body. The slow cooling operation is continued on the glass body. The slow cooling operation was carried out by holding the glass body in another electric furnace set at 800 ° C for 2 hours, cooling to 740 ° C for 2 hours, and further cooling to 660 ° C for 2 hours, and then cutting the electric furnace. The power is supplied and cooled to room temperature. The glass body subjected to the slow cooling operation was used as a sample glass. The sample glass is used for measurement which is not affected by the slow cooling condition and/or which cannot be measured in a substrate form (devitrification temperature, thermal expansion coefficient, Tg, and strain point). The sample glass is cut, ground and polished. It is a cylindrical shape of 5 mm and a length of 20 mm, and it is held at Tg for 30 minutes, then cooled to Tg-100 ° C at 100 ° C / min, and cooled to room temperature, thereby preparing a sample glass for heat shrinkage measurement. . (Strain point) A test piece was produced by cutting and grinding the above-mentioned sample glass into a column shape of 3 mm square and a length of 55 mm. The test piece was measured using a curved beam measuring device (manufactured by Tokyo Industrial Co., Ltd.), and strain was calculated by calculation according to the bending method (ASTM (American Society for Testing and Materials) C-598) point. (Heat Shrinkage Ratio) The heat shrinkage rate is obtained by raising the temperature from normal temperature at 10 ° C/min and holding at 550 ° C for 2 hours, and then, after shrinking at 10 ° C / min to normal temperature, the shrinkage amount of the sample glass for heat shrinkage measurement is borrowed. It is obtained by the following formula. Heat shrinkage rate (ppm) = {shrinkage of glass before and after heat treatment / length of glass before heat treatment} × 10 6 (Method for Measuring Devitrification Temperature) The sample glass was pulverized and passed through a sieve of 2380 μm to obtain glass granules remaining on a sieve of 1000 μm. The glass granules were immersed in ethanol and subjected to ultrasonic cleaning, and then dried in a thermostat. The dried glass granules were placed on a platinum crucible having a width of 12 mm, a length of 200 mm and a depth of 10 mm so that 25 g of the above-mentioned glass granules became a substantially constant thickness. The platinum crucible was held in an electric furnace having a temperature gradient of 1080 to 1400 ° C for 5 hours, and thereafter, it was taken out from the furnace, and the devitrification generated inside the glass was observed with a 50-fold optical microscope. The highest temperature at which devitrification was observed was set as the devitrification temperature. (Method for measuring average thermal expansion coefficient α and Tg in the range of 100 to 300 ° C) The above sample glass is processed into A test piece was prepared for a cylindrical shape of 5 mm and a length of 20 mm. The test piece was measured for temperature during the temperature rise and the amount of expansion and contraction of the test piece using a differential thermal dilatometer (Thermo Plus 2 TMA8310). The rate of temperature rise at this time was set to 5 ° C / min. Based on the measurement results of the above temperature and the amount of expansion and contraction of the test piece, the average thermal expansion coefficient and Tg in the temperature range of 100 to 300 ° C were determined. In addition, in the present invention, the Tg means that the glass body is kept in another electric furnace set at 800 ° C for 2 hours, then cooled to 740 ° C in 2 hours, and further cooled to 660 ° C in 2 hours, and then the electric furnace is cut. The sample was obtained by measuring the power of the sample and cooling it to room temperature. (Density) The density of the glass is determined by the Archimedes method. (etching rate) The etching rate (μm/h) is expressed by preparing the sample glass (12.5 mm × 20 mm × 0.7 mm) in such a manner that the HF concentration is 1 mol/kg and the HCl concentration is 5 mol/kg. The thickness reduction (μm) of the surface of one of the glass substrates per unit time (1 hour) in the case of immersion in an etching solution (200 ml) at 40 ° C for 1 hour. The glass raw material blended in such a manner as the composition shown in the examples is melted at 1560 to 1640 ° C using a continuous melting apparatus having a melting tank made of a refractory brick containing a high zirconia refractory and a platinum alloy. After being clarified at 1620 to 1670 ° C and stirred at 1440 to 1530 ° C, it is formed into a thin plate having a thickness of 0.7 mm by an overflow down-draw method, and is in a temperature range from Tg to Tg-100 ° C at 100 ° C/min. The speed is slowly cooled to obtain a glass substrate. Further, each of the characteristics described above was measured using the obtained glass substrate. Further, the heat shrinkage ratio was determined by the following method. After a linear mark is attached to a specific position of the glass substrate, a cut line is vertically added to the glass substrate and divided into two glass sheets. Then, only one piece of the glass plate was subjected to heat treatment at 550 ° C for 2 hours. Thereafter, the heat-treated glass sheet and the untreated glass sheet were placed in parallel and fixed by an adhesive tape, and the offset of the mark was measured, and the heat shrinkage ratio was determined by the following formula. Heat shrinkage rate (ppm) = {shrinkage of glass before and after heat treatment / length of glass before heat treatment} × 10 6 The glass obtained in the above manner has a heat shrinkage ratio of 3 ppm or more and less than 75 ppm. Also, the devitrification temperature did not reach 1280 °C. Therefore, by using the glass, an overflow down-draw method can be used to manufacture a glass substrate which can be used for a display using an LTPS-TFT. Moreover, these glass substrates are also suitable as a glass substrate for OS-TFT.

無no

無no

無no

Claims (10)

一種平面面板顯示器用玻璃基板，其以莫耳%表示含有： 55~80%之SiO2 、 8~20%之Al2 O3 、 0~8%之B2 O3 、 超過0%~15%之MgO、 4~13%之CaO、 0~15%之SrO、 0~10%之BaO；其中 Li2 O、Na2 O及K2 O之合計量超過0.1 mol%且為0.5 mol%以下， 且不含Y2 O3 及La2 O3 ， SiO2 +2×Al2 O3 為100%以下； SiO2 -(1/2)×Al2 O3 為50~63 mol%， 莫耳比B2 O3 /(SiO2 +Al2 O3 )為0~0.12； 莫耳比MgO/RO(其中，RO為MgO、CaO、SrO及BaO之合計量)為0.15~0.9之範圍； 應變點為690℃以上； 玻璃轉移溫度為740℃以上； 失透溫度為1235℃以下。A glass substrate for a flat panel display, which is expressed by mol%: 55 to 80% of SiO 2 , 8 to 20% of Al 2 O 3 , 0 to 8% of B 2 O 3 , and more than 0% to 15% MgO, 4 to 13% CaO, 0 to 15% SrO, 0 to 10% BaO; wherein the total amount of Li 2 O, Na 2 O and K 2 O is more than 0.1 mol% and less than 0.5 mol%, And does not contain Y 2 O 3 and La 2 O 3 , SiO 2 + 2 × Al 2 O 3 is 100% or less; SiO 2 -(1/2) × Al 2 O 3 is 50 to 63 mol%, Mo Erbi B 2 O 3 /(SiO 2 +Al 2 O 3 ) is 0 to 0.12; Mohr ratio MgO/RO (where RO is the total amount of MgO, CaO, SrO and BaO) is in the range of 0.15 to 0.9; strain point It is above 690 ° C; the glass transition temperature is above 740 ° C; and the devitrification temperature is below 1235 ° C. 一種平面面板顯示器用玻璃基板，其以莫耳%表示含有： 55~80%之SiO2 、 8~20%之Al2 O3 、 0~8%之B2 O3 、 超過0%~15%之MgO、 0~20%之CaO、 0~4%之SrO、 0~10%之BaO；其中 Li2 O、Na2 O及K2 O之合計量超過0.1 mol%且為0.5 mol%以下， 且不含Y2 O3 及La2 O3 ， SiO2 +2×Al2 O3 為100%以下； SiO2 -(1/2)×Al2 O3 為50~63 mol%， 莫耳比B2 O3 /(SiO2 +Al2 O3 )為0~0.12； 莫耳比MgO/RO(其中，RO為MgO、CaO、SrO及BaO之合計量)為0.15~0.9之範圍； 應變點為690℃以上； 玻璃轉移溫度為740℃以上； 失透溫度為1235℃以下。A glass substrate for a flat panel display, which is expressed by mol%: 55 to 80% of SiO 2 , 8 to 20% of Al 2 O 3 , 0 to 8% of B 2 O 3 , more than 0% to 15% MgO, 0-20% CaO, 0-4% SrO, 0-10% BaO; wherein the total amount of Li 2 O, Na 2 O and K 2 O is more than 0.1 mol% and less than 0.5 mol%, And does not contain Y 2 O 3 and La 2 O 3 , SiO 2 + 2 × Al 2 O 3 is 100% or less; SiO 2 -(1/2) × Al 2 O 3 is 50 to 63 mol%, Mo Erbi B 2 O 3 /(SiO 2 +Al 2 O 3 ) is 0 to 0.12; Mohr ratio MgO/RO (where RO is the total amount of MgO, CaO, SrO and BaO) is in the range of 0.15 to 0.9; strain point It is above 690 ° C; the glass transition temperature is above 740 ° C; and the devitrification temperature is below 1235 ° C. 如請求項1或2之玻璃基板，其中自常溫以10℃/min升溫，以550℃保持2小時，其後，以10℃/min降溫至常溫後以下式所表示之熱收縮率為3 ppm以上且未達75 ppm， 熱收縮率(ppm)={熱處理前後之玻璃之收縮量/熱處理前之玻璃之長度}×106 。The glass substrate of claim 1 or 2, wherein the temperature is raised at 10 ° C / min from normal temperature, maintained at 550 ° C for 2 hours, and thereafter, after 10 ° C / min is cooled to normal temperature, the heat shrinkage ratio represented by the following formula is 3 ppm. Above and below 75 ppm, the heat shrinkage rate (ppm) = {the amount of shrinkage of the glass before and after the heat treatment / the length of the glass before the heat treatment} × 10 6 . 如請求項1至3中任一項之玻璃基板，其以莫耳%表示含有： 63~70%之SiO2 、 12~15%之Al2 O3 、 1.5~7%之B2 O3 、 3~11%之MgO、 5~11%之CaO、 0~4%之SrO、及 0~4%之BaO。The glass substrate according to any one of claims 1 to 3, which is represented by mol%: 63 to 70% of SiO 2 , 12 to 15% of Al 2 O 3 , 1.5 to 7% of B 2 O 3 , 3 to 11% of MgO, 5 to 11% of CaO, 0 to 4% of SrO, and 0 to 4% of BaO. 如請求項1至4中任一項之玻璃基板，其中 含有SnO2 及Fe2 O3 ；且 以莫耳%表示， SnO2 為0.03~0.15%， SnO2 與Fe2 O3 之合計量為0.05~0.2%之範圍。The glass substrate according to any one of claims 1 to 4, which contains SnO 2 and Fe 2 O 3 ; and expressed by mol %, SnO 2 is 0.03 to 0.15%, and the total amount of SnO 2 and Fe 2 O 3 is 0.05~0.2% range. 如請求項1至5中任一項之玻璃基板，其實質上不含As2 O3 及Sb2 O3 。The glass substrate according to any one of claims 1 to 5, which is substantially free of As 2 O 3 and Sb 2 O 3 . 如請求項1至6中任一項之玻璃基板，其於100~300℃下之平均熱膨脹係數為28×10-7 ℃-1 以上且未達50×10-7 ℃-1 。The glass substrate according to any one of claims 1 to 6, which has an average thermal expansion coefficient at 80 to 300 ° C of 28 × 10 -7 ° C -1 or more and less than 50 × 10 -7 ° C -1 . 一種平面面板顯示器，其係於玻璃基板表面形成有由LTPS或氧化物半導體形成之薄膜電晶體者，且上述玻璃基板為如請求項1至8中任一項之玻璃基板。A flat panel display in which a thin film transistor formed of LTPS or an oxide semiconductor is formed on a surface of a glass substrate, and the glass substrate is a glass substrate according to any one of claims 1 to 8. 一種平面面板顯示器，其係具備玻璃基板之液晶顯示器或有機EL顯示器，且上述玻璃基板為如請求項1至8中任一項之玻璃基板。A flat panel display comprising a liquid crystal display of a glass substrate or an organic EL display, and the glass substrate is the glass substrate according to any one of claims 1 to 8. 一種如請求項1至8中任一項之平面面板顯示器用玻璃基板之製造方法，其包括以下步驟： 熔解步驟，其將調合成特定組成之玻璃原料熔解； 成形步驟，其將上述熔解步驟中熔解而成之熔融玻璃成形為平板狀玻璃；及 緩冷卻步驟，其係對上述平板狀玻璃進行緩冷卻之步驟，且係以降低上述平板狀玻璃之熱收縮率之方式控制上述平板狀玻璃之冷卻條件。A method for producing a glass substrate for a flat panel display according to any one of claims 1 to 8, comprising the steps of: a melting step of melting a glass raw material tuned to a specific composition; and a forming step of the melting step The melted molten glass is formed into a flat glass; and a slow cooling step is a step of slowly cooling the flat glass, and controlling the flat glass by reducing the heat shrinkage rate of the flat glass Cooling conditions.
TW106118410A 2011-12-28 2012-12-28 Glass substrate for flat panel display and manufacturing method thereof TWI644880B (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2011-288651 2011-12-28
JP2011288651 2011-12-28
JP2012187879 2012-08-28
JP2012-187879 2012-08-28

Publications (2)

Publication Number Publication Date
TW201731787A true TW201731787A (en) 2017-09-16
TWI644880B TWI644880B (en) 2018-12-21

Family

ID=48697451

Family Applications (4)

Application Number Title Priority Date Filing Date
TW107139024A TWI673246B (en) 2011-12-28 2012-12-28 Glass substrate for flat panel display and manufacturing method thereof
TW104132598A TWI594967B (en) 2011-12-28 2012-12-28 Glass substrate for flat panel display and its manufacturing method
TW101150993A TWI510447B (en) 2011-12-28 2012-12-28 Glass substrate for flat panel display and method for manufacturing the same
TW106118410A TWI644880B (en) 2011-12-28 2012-12-28 Glass substrate for flat panel display and manufacturing method thereof

Family Applications Before (3)

Application Number Title Priority Date Filing Date
TW107139024A TWI673246B (en) 2011-12-28 2012-12-28 Glass substrate for flat panel display and manufacturing method thereof
TW104132598A TWI594967B (en) 2011-12-28 2012-12-28 Glass substrate for flat panel display and its manufacturing method
TW101150993A TWI510447B (en) 2011-12-28 2012-12-28 Glass substrate for flat panel display and method for manufacturing the same

Country Status (5)

Country Link
JP (2) JP5805180B2 (en)
KR (3) KR101951085B1 (en)
CN (2) CN108314314A (en)
TW (4) TWI673246B (en)
WO (1) WO2013099970A1 (en)

Families Citing this family (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108314314A (en) * 2011-12-28 2018-07-24 安瀚视特控股株式会社 Flat panel display glass substrate and its manufacturing method
KR102077212B1 (en) * 2012-12-05 2020-02-13 에이지씨 가부시키가이샤 Non-alkali glass substrate
JP6447510B2 (en) * 2013-11-28 2019-01-09 Ａｇｃ株式会社 Non-alkali glass substrate and method for thinning alkali-free glass substrate
JP6031613B2 (en) * 2014-06-30 2016-11-24 ＡｖａｎＳｔｒａｔｅ株式会社 Sheet glass manufacturing method and sheet glass manufacturing apparatus
JP6671368B2 (en) * 2014-12-08 2020-03-25 コーニング インコーポレイテッド Low consolidation laminated glass articles and methods of forming
JP7060915B2 (en) * 2014-12-12 2022-04-27 日本電気硝子株式会社 Alkaline-free glass
WO2016125792A1 (en) * 2015-02-06 2016-08-11 旭硝子株式会社 Selectively light-transmitting glass and laminated substrate
GB201505091D0 (en) 2015-03-26 2015-05-06 Pilkington Group Ltd Glass
CN108349785B (en) * 2015-12-01 2021-03-26 科立视材料科技有限公司 Low-boron barium-free alkaline earth aluminosilicate glass and application thereof
WO2017188126A1 (en) * 2016-04-27 2017-11-02 旭硝子株式会社 Non-alkali glass
WO2017204167A1 (en) * 2016-05-25 2017-11-30 旭硝子株式会社 Alkali-free glass substrate, laminated substrate, and method for manufacturing glass substrate
JP7110981B2 (en) * 2016-08-05 2022-08-02 Ａｇｃ株式会社 Glass substrates, semiconductor devices and display devices
US11066326B2 (en) 2016-12-20 2021-07-20 Nippon Electric Glass Co., Ltd. Glass
WO2018151166A1 (en) * 2017-02-15 2018-08-23 Ａｇｃ株式会社 Method for molding molten glass, molding apparatus, and method for producing glass articles
WO2018225627A1 (en) * 2017-06-05 2018-12-13 Ａｇｃ株式会社 Tempered glass
US10829408B2 (en) * 2017-12-13 2020-11-10 Corning Incorporated Glass-ceramics and methods of making the same
CN111630010A (en) * 2018-01-23 2020-09-04 日本电气硝子株式会社 Glass substrate and method for manufacturing same
CN111867992B (en) * 2018-03-09 2022-12-06 Ａｇｃ株式会社 Alkali-free glass substrate
WO2019205938A1 (en) * 2018-04-25 2019-10-31 成都光明光电股份有限公司 Glass composition
WO2020027088A1 (en) * 2018-07-31 2020-02-06 日本電気硝子株式会社 Substrate for displays and method for producing same
JP7389400B2 (en) * 2018-10-15 2023-11-30 日本電気硝子株式会社 Alkali-free glass plate
CN110357420B (en) * 2019-07-23 2022-03-04 中国洛阳浮法玻璃集团有限责任公司 Preparation method of electronic substrate glass with low thermal shrinkage
CN110862228A (en) * 2019-09-29 2020-03-06 彩虹显示器件股份有限公司 Preparation method of glass substrate
KR20240006552A (en) * 2021-05-10 2024-01-15 니폰 덴키 가라스 가부시키가이샤 Alkali-free glass plate
TW202319363A (en) * 2021-06-28 2023-05-16 日商日本電氣硝子股份有限公司 Alkali-free glass panel

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3858293B2 (en) * 1995-12-11 2006-12-13 日本電気硝子株式会社 Alkali-free glass substrate
JP3988209B2 (en) * 1996-06-03 2007-10-10 旭硝子株式会社 Alkali-free glass and liquid crystal display panel
JP3804112B2 (en) * 1996-07-29 2006-08-02 旭硝子株式会社 Alkali-free glass, alkali-free glass manufacturing method and flat display panel
DE19916296C1 (en) * 1999-04-12 2001-01-18 Schott Glas Alkali-free aluminoborosilicate glass and its use
JP4534282B2 (en) * 1999-12-14 2010-09-01 旭硝子株式会社 Glass for liquid crystal display substrates
JP2004315354A (en) 2003-03-31 2004-11-11 Asahi Glass Co Ltd Alkali-free glass
JP5105571B2 (en) * 2003-10-10 2012-12-26 日本電気硝子株式会社 Method for producing alkali-free glass
KR101296962B1 (en) * 2005-08-15 2013-08-14 아반스트레이트 가부시키가이샤 Glass composition
KR101282952B1 (en) * 2006-01-12 2013-07-08 니폰 덴키 가라스 가부시키가이샤 Alkali-free glass substrate
CN103121796B (en) * 2006-02-10 2017-03-29 康宁股份有限公司 Glass composition with high heat stability and chemical stability and preparation method thereof
JP5088670B2 (en) 2006-04-11 2012-12-05 日本電気硝子株式会社 Glass substrate for display
TWI414502B (en) * 2008-05-13 2013-11-11 Corning Inc Rare-earth-containing glass material and substrate and device comprising such substrate
EP2450319A4 (en) * 2009-07-02 2015-01-28 Asahi Glass Co Ltd Alkali-free glass and method for producing same
JP5375385B2 (en) * 2009-07-13 2013-12-25 日本電気硝子株式会社 Manufacturing method of glass substrate
JP5537144B2 (en) * 2009-12-16 2014-07-02 ＡｖａｎＳｔｒａｔｅ株式会社 Glass composition and glass substrate for flat panel display using the same
CN108314314A (en) * 2011-12-28 2018-07-24 安瀚视特控股株式会社 Flat panel display glass substrate and its manufacturing method

Also Published As

Publication number Publication date
TW201332929A (en) 2013-08-16
JPWO2013099970A1 (en) 2015-05-11
TWI510447B (en) 2015-12-01
CN108314314A (en) 2018-07-24
KR20140074245A (en) 2014-06-17
JP6105539B2 (en) 2017-03-29
TWI673246B (en) 2019-10-01
KR101654753B1 (en) 2016-09-08
KR101951085B1 (en) 2019-02-21
KR20160106206A (en) 2016-09-09
JP2015083533A (en) 2015-04-30
TWI594967B (en) 2017-08-11
JP5805180B2 (en) 2015-11-04
CN103429547A (en) 2013-12-04
KR102043599B1 (en) 2019-11-11
KR20190020169A (en) 2019-02-27
TW201908259A (en) 2019-03-01
WO2013099970A1 (en) 2013-07-04
TWI644880B (en) 2018-12-21
TW201619087A (en) 2016-06-01

Similar Documents

Publication Publication Date Title
TWI510447B (en) Glass substrate for flat panel display and method for manufacturing the same
JP6539250B2 (en) Glass substrate for flat panel display and method of manufacturing the same
JP6420282B2 (en) Glass substrate for flat panel display and manufacturing method thereof
JP6375277B2 (en) Glass substrate for display and manufacturing method thereof
JP6692812B2 (en) Glass substrate for display and manufacturing method thereof
TW201305081A (en) Glass substrate for flat panel display and manufacturing method thereof
JP6757159B2 (en) Glass substrate for magnetic recording medium and its manufacturing method
TW201706222A (en) Glass substrate for display and method for producing same
JP5753895B2 (en) Glass substrate for flat panel display