201236984, 六、發明說明： 【發明所屬之技術領域】 本發明是有關於一種用於藉由溢流下拉法（〇verflQw down draw)來製造板玻璃的技術的改良。 【先前技術】 如眾所周知般，在液晶顯示器、電漿顯示器、有機電 致發光（ElectroLuminescence ’ EL )顯示器等的平板顯示 器（Flat Panel Display，FPD)用的玻璃基板，或以有機 EL照明用的玻璃基板為代表的用於各種領域的板玻璃 中，有時要求對於表面缺陷或彎曲嚴格的製品品質。 為了能夠應對此種要求，且為了獲得平滑且無缺陷的 玻璃表面’而利用稱作溢流下拉法的製造方法。 該製造方法為如下方法：使炫融玻璃流入成形體的頂 部的溢流溝槽中，並使從該溢流溝槽向兩側溢出的熔融玻 璃一面經由成形體的頂部平面部而沿著成形體的呈大致楔 狀的外侧面部流下，一面在上述成形體的下端部融合一體 化，從而連續成形1塊板玻璃。 然而’該溢流下拉法中所使用的成形體包含氧化鋁耐 火物、氧化锆耐火物等的耐火物。若在該成形體上流下熔 融玻璃，則成形體成分會溶析在熔融玻璃中，該溶析的成 形體成分發生結晶，II此存在成形的玻璃板的品質降低的 情況。 針對此種問題’考慮使成形體的與熔融玻璃接觸的部 位由相對於炫融玻璃具有耐腐蝕性的金屬來被覆。這樣， 201236984 4l494pif 已針對由耐腐錄金屬來被覆成形體而提出了幾個 例如，在專利文獻丨所揭示的溢流下拉法中，由 的整個表面__合金的金屬板來進行 ^金屬板的熔融玻璃接觸部位的板厚比其他部位的板 的目的在於：抑制由覆蓋成形體的整個表_ u金的金屬板來進行被覆的情況τ所產生的如下 開始:二=象=_玻璃的熱而金屬板從成形體 形體的方向^屬板中的騎玻璃接觸部位向離開成 方法中’可藉由如下的理由來抑制該現象。首先， 相較熔融玻璃接觸部位，其以外的部位更容 _子潯而引起向離開成形體的方向的變形。因 =^而沿著成形體表面產生了金屬板的熱』 方向的變形。藉此，溶融玻璃】= 熱膨脹被吸收，從而縣麵接觸部位 的向離開成形體的方向的變形得以抑制。 益’例如’專利文獻2所揭示的溢流下拉法中，亦 I麗，/而在成形體的與溶融玻璃接觸的面形成鉬等的貴 备屬膜。 、/ ，例如，專利文獻3所揭示的溢流下拉法中，在 成形體的下端部配設著鉑或鉑合金的金屬板。 先前技術文獻 專利文獻 4 201236984 1 :日本專利特開平5]娜6號公報 寻利文獻3 :日本真刹扭m 然而，專利文獻！ ^ _81653號公報 被覆整個成形體而可以理解’如根據金屬板 部位在成形體上為連續的。因又此1 =的炫融玻璃接觸 況下，存在如下的形體表面發生熱膨脹的情 b 在炫融玻璃接觸部位連續的方 成形體開始發生熱 地施加應力’藉此亦有可能在成频上產生裂紋。 -而且’專利文獻2巾所揭*的方法亦與專利文獻^所 揭示的方法同樣地，因溶融玻璃的熱而貴金屬膜從成形體 開始發生熱膨脹，藉此貴金屬膜有可能向離開成形體的方 向發生變形，或者有可能在成形體產生裂紋。 而且，如專利文獻3所揭示的方法般，在成形體的下 端部配設著不同於成形體的另外的金屬板的情況下，成形 體的下端部為溶融玻璃融合一體化的部位，因此有對成升多 的板玻璃的表面精度造成不良影響之虞。 ^ 【發明内容】 本發明鑒於上述情況’其技術性課題在於：藉由溢法 下拉法，在為了抑制成形體的成分向熔融玻璃的溶析而利 201236984 41494pif 用金屬來被覆成形體的情況下，可避免被覆金屬發生變形 的事態或成形體產生裂紋的事態，並且可良好地維持成形 的板玻璃的表面精度。 為了解決上述課題而創作的本發明的板玻璃製造裝置 包括成形體，該成形體在頂部具有溢流溝槽，且具有形成 在該溢流溝槽的兩側且彼此在下端連接的一對外側面部， 使熔融玻璃流入上述溢流溝槽，使從上述溢流溝槽中溢出 的上述熔融玻璃一面沿著上述一對外側面部流下一面在上 述-對外側面部的下端融合-體化，從而成形板玻璃；該 板玻璃製造裝置的賴松：僅在上述成碰的表面中的 上述溢流溝槽的内面設置著包含金屬的被覆部。 在成形體與熔融玻璃接觸的情況下，考慮到成形體成 分向熔融玻璃溶析的情況，除兩者的化學組成、兩者接觸 的時間之外，兩者的溫度也產生大的料。隨聽融玻璃 與成形體的溫度-併升高’兩者的界面的物質移動旺盛， 成形體成分向炫融玻璃的溶析增多。在成形體的表面，溢 流，槽中的内面為最初熔融玻璃所接觸的部位，因而溫度 最高。因^，成形體成分從該内面開始溶析在熔融玻璃中 的可能性高。上述裝置中，因該内面由包含金屬的被覆部 所被覆，故可有效地抑制成形體成分向熔融玻璃的溶析。 另方面，成形體中的溢流溝槽的内面以外的表面並 包含金屬的被覆部所被覆，被覆部成為成形體上的一 部分，其表面積少。因此，在因騎玻璃的熱而被覆部的 金屬與成频向沿著表面的方向發生鮮脹崎況下就 6 201236984^ f膨脹的長度而言，兩者的差被限定。因此，能夠抑制因 被物編離_鍋方向的變形 勺八：Ϊαλ"^裝置中，因成形體的外側面部的表面未由 包3金屬的被覆部所被覆，故在該表面，不會產生因熱膨 脹引起的金屬向離開成形體的方向的變形或成形體的裂 ，。因此，與由金屬所被覆的情況相比，該表面在板玻璃 良好地維縣面精度。_表面為關玻璃融合 流下的部位’故亦可良好地維持成形的板玻璃的 表面精度。 上述裝置中’較佳為上述被覆部設置在上述溢流溝槽 中的内面的80%以上的範圍内。 據此，能夠充分地享有抑制成形體成分向溶融玻 溶析的效果。 任裝置中，較佳為不進行通過上述被覆部的通電加 "、'。據此，在被覆部附近的成形體表面，容易抑制成形體 成分向熔融玻璃的溶析。 、上述任-裝置中，較佳為上述被覆部為藉由炫射而形 成的金屬膜。 被覆部的金屬只要為金屬膜的形態，則可直接形成在 成开y體表面，從而與將板狀形態的金屬利用焊接等固定在 成形，表面的情況祕，能夠容易地被誠形體表面。而 且若金屬膜藉由熔射而形成，則成膜快，而且，對成形 體賦予的熱的f彡響少’因而可抑制因成膜而胁的成形體 201236984 41494pif 的變形或應變。熔射的種類未作特別限定，例如為火焰熔 射（flame spraying)、電漿熔射（plasmaspraying)等。 上述任一裝置中，較佳為上述被覆部由鉑或鉑合金而 形成。 據此，即便在熔融玻璃的溫度超過1〇〇(rc的情況下， 被覆部的金屬亦不易熔解。作為鉑合金，例如可列舉鉑· 姥合金、始·銀合金等。 上述任一裝置中，較佳為該金屬膜的厚度為5〇〜 1000 μιη 〇 只要作為被覆部的金屬膜的厚度為5〇μπι以上，則可 抑制在板玻璃成形時產生的金屬膜的剝落或裂紋。只要作 為被覆部的金屬膜的厚度為簡卿以下，則可抑制炼射 時在金屬膜側產生的裂紋或剝離。而且，在板玻璃成形時， 月b夠避免因熔融玻璃的流動被金屬膜妨礙而導致板玻璃的 表面精度降低的事態。 而且，為了解決上述課題而創作的本發明的板玻璃製 造方法，包括成形體，該成形體在頂部具有溢流溝槽，且 具有开>成在該溢流溝槽的兩側且彼此在下端連接的一對外 側面，使炫融玻璃流入上述溢流溝槽，使從上述溢流溝 槽中溢出的上述熔融玻璃一面沿著上述一對外側面部流下 一面在上述一對外側面部的下端融合一體化，從而成形板 玻璃；上述板玻璃製造方法的特徵在於：作為上述成形體， 使用僅在其表面中的上述溢流溝槽的内面設置著包含金屬 的被覆部的成形體。 8 201236984 • i 、邊方法的構成與上述本發明的板玻璃製造裝置中開頭 所述的裝置的構成實質相同，因而其作用效果與關於該裝 置所述的作用效果實質相同。 [發明的效果] 、、根據本發明，藉由溢流下拉法，在為了抑制成形體的 成分向熔融玻璃的溶析而利用金屬來被覆成形體的情況 下i可避免被覆金屬發生變形的事態或成形體產生裂紋的 事悲、’並且可良好地維持成形的板玻璃的表面精度。 【實施方式】 以下’根據圖式對用以實施本發明的形態進行說明。 圖1A是表示本發明的實施形態的板玻璃製造裝置的 要部的概略正面圖。如該圖1A所示，該薄板玻璃製造裝 置包括用於執行溢流下拉法的成形體1。 〜成形體1如該圖1A所示，沿著與要製造的薄板玻璃 的寬度方向相對應的方向為長條狀，且以如下各部為主要 構成要素：在頂部沿著其長度方向形成的溢流溝槽2，從 兩上端開口緣延伸至外側方的成形體1的頂部平面部3， 及以楔狀朝向下方而彼此逐漸接近的一對外側面部4。成 形體1的下端部被稱作底部（r〇〇t) 5，且成形體1中的兩 侧的外侧面部4的下端藉由彼此連接而構成。成形體1由 相對於溶融玻璃g具有耐腐蝕性的例如氧化鋁耐火物、氧 化錯耐火物等形成。 在本實施形態的成形體1中設置著導引件6。導引件6 包含銘或其合金’且配設在兩外侧面部4及底部5的長度 201236984 41494pif 方向兩端。導引件6從成形體1的溢流溝槽2延伸至頂部 平面部3、兩外側面部4及底部5為止，具有對熔融玻璃g 的流下的寬度進行規定的作用。 在溢流溝槽2的長度方向一端侧連結著供給熔融玻璃 g的供給管7。本實施形態中，溢流溝槽2為以流路底板8 為下纟而的剖面V字狀。溢流溝槽2的流路底板8以隨著從 熔融玻螭g的流動方向的始端部側向終端部側移行而逐漸 變高的方式而被附以斜率。 溢流溝槽2的内面藉由作為由熔射形成的被覆部的金 屬膜9所被覆，另一方面，頂部平面部3與外側面部4的 表面的全部坯料露出。由金屬膜9被膜的部分為溢流溝槽 2的内面的至少一部分即可，本實施形態中，為溢流溝槽2 的内面的80%，但亦可為80%以上。而且，如圖1B所示， 本實施形態中包含流路底板8在内且從溢流溝槽2的流路 底板8朝向上端而連續地由金屬膜9所被覆。金屬膜9的 上端與溢流溝槽2的上端間的距離在溢流溝槽2的延伸方 向上為固定。而且，該距離在溢流溝槽2的—對側面為相 同。本實施形態中，金屬膜9的材質為鉑，但亦可為鉑合 金。而且，本實施形態中，作為成膜方法，而使用火焰熔 射，亦可例如使用電漿熔射等的其他熔射。而且，金屬膜 9可由熔射以外的方法例如蒸鍍等形成。此外，為了容易 理解’將金屬膜9圖示得比實際厚。 金屬膜9的厚度例如為5〇 μιη〜1〇〇〇 μιη，較佳為 μιη〜500 μηι，本實施形態中為25〇 μιη。若金屬膜的厚 201236984 度小於50 μιη，則在板玻璃成形時，可能產生金屬膜$的 剝離或裂紋，或者可能產生由熔融玻璃g引起的金屬膜9 的铋蝕。若金屬膜9的厚度超過1〇〇〇 μιη，則在熔射時可 能在金屬膜9的一側產生裂紋或剝離。而且，若金屬膜9 的厚度超過1000 μιη，則在板玻璃成形時，因金屬膜9妨 礙溶融玻璃g机動，從而對成形的板玻璃的表面精度造成 不良景>響。而且，若考慮到成形的板玻璃的表面精度，則 較佳為金屬膜9的厚度在板寬度方向上均一。 以下，對使用了上述裝置的板玻璃的製造方法進 明。 首先，在玻璃熔融爐（省略圖示）中熔融例如無鹼玻 璃（例如日本電硝子股份有限公司製造〇A_1〇G)等的玻 璃的原料。其次，使該熔融玻璃g經由供給管7而流入成 形體1的溢流溝槽2中。 若熔融玻璃g以規定量流入溢流溝槽2中，則熔融玻 螭g從溢流溝槽2經由其兩侧的頂部平面部3並沿著兩外 侧面部4而流下。 該溶融玻璃g在成形體1的底部5融合一體化。該一 體化的溶融玻璃g藉由配設在下方的輥等的牽引機構（省 略圖不）拉伸並且被冷卻’而連續地成形出板玻璃。 如上述般構成的本實施形態的板玻璃製造裝置中，可 享有以下的效果。 因成形體成分溶析在熔融玻璃g的可能性高的溢流溝 槽2的内面被始的金屬膜9所被覆，故可有效地抑制成形 11 201236984 41494pif 體成分向熔融玻璃g的溶析。另—方面，成形體i的頂部 平面部3與外侧面部4的表面未被金屬膜9所被覆，金屬 膜9被覆的部位成為成形體〗上的-部分，其表面積少。 因此，在祕融玻璃g的熱而金屬膜9與成形體〗向沿著 表面的方向發生__軌下，就其雜的長度而言， 兩者的差被限^。因此’能夠抑制因熱膨脹引起的金屬膜 9向離開成形體1的方向的變形或成形體i的裂紋。 、而且，因成形體1的外側面部4的表面未被金屬膜9 所被覆，故絲面並不會產生因㈣玻璃g的熱而金屬膜 9發生熱膨脹從而離開成形體1這樣的變形，或由金屬膜9 攸成形體1開始發生熱膨脹㈣_成雜丨的裂紋。因 此’與該表面由金屬膜9被覆的情況相比，在板玻璃成形 時，其表面的表面精度得以良好地維持。因該表面為炫融 破璃g融合-體化前流下的部位，故顏的減璃的表面 精度亦得以良好地維持。 此外，上述實施形 〜取叩瓶丄的則面部4白( 個為單一的平面，但本發明並不限定於此。例如，如圖 所示，外側面部4的各個亦可將垂直面部知與傾斜夜 4b上下連接而構成。亦即，外側面部4的至少下侧部^ 向下方而彼此逐漸接近’其下端相互連接，萨 體1的底部5即可。 魏斑 而且，上述實施形態中，溢流溝槽2剖面為v字狀， 但本發明並不限定於此。例如，如圖2所示，剖面亦可為 矩形狀，還可為ϋ字狀。 一 12 201236984 而且，上述實施形態中，溢流溝槽2的内面藉由利用 熔射而形成的金屬膜9所被覆，但本發明並不限定於此， 金屬膜9亦可利用熔射以外的方法形成。而且，溢流溝槽 2的内面亦可不藉由金屬膜9而由金屬板等的金屬構件被 覆。 本發明並不限定於以上的說明，只要在其技術性思想 範圍内，則可進行各種變形。 【圖式簡單說明】 圖1A是表示本發明的實施形態的板玻璃製造裝置的 要部的圖，且是概略正面圖。 圖1B是表示本發明的實施形態的板玻璃製造裝置的 要部的圖，且是圖1A的X-X線前視剖面圖。 圖2是表示本發明的其他例的剖面圖。 【主要元件符號說明】 1 成形體 2 溢流溝槽 3 頂部平面部 4 外側面部 4a :垂直面部 4b :傾斜面部 5 :底部 6 :導引件 7 :供給管 8 :流路底板 13 201236984 414y4pif 9 :金屬膜（被覆部） g:溶融玻璃 14201236984, VI. Description of the Invention: [Technical Field of the Invention] The present invention relates to an improvement of a technique for manufacturing sheet glass by a 下拉verflQw down draw method. [Prior Art] As is well known, a glass substrate for a flat panel display (FPD) such as a liquid crystal display, a plasma display, an organic electroluminescence (EL) display, or a glass for organic EL illumination In the sheet glass used for various fields, which is representative of the substrate, it is sometimes required to have strict product quality for surface defects or bending. In order to be able to cope with such a demand, and in order to obtain a smooth and defect-free glass surface, a manufacturing method called an overflow down-draw method is utilized. This manufacturing method is a method in which the glazing glass flows into the overflow groove at the top of the formed body, and the molten glass overflowing from the overflow groove to both sides is formed along the top flat portion of the formed body. The outer side surface of the body having a substantially wedge shape flows down and is integrated and integrated at the lower end portion of the molded body to continuously form one plate glass. However, the molded body used in the overflow down-draw method contains a refractory such as an alumina flame resistant material or a zirconia refractory. When the molten glass flows down the molded body, the molded body component is eluted in the molten glass, and the dissolved constituent component is crystallized, whereby the quality of the formed glass plate may be lowered. In response to such a problem, it is considered that the portion of the molded body that is in contact with the molten glass is covered with a metal having corrosion resistance with respect to the molten glass. Thus, 201236984 4l494pif has been proposed for coating a molded body from a corrosion-resistant metal. For example, in the overflow down-draw method disclosed in the patent document, the metal plate of the entire surface is alloyed. The thickness of the molten glass contact portion is greater than that of the other portions of the plate in order to suppress the occurrence of the coating τ by covering the entire surface of the molded body with the metal sheet τ: = = = = = glass The heat can be suppressed from the direction in which the metal plate is removed from the glass-contacting portion of the plate in the direction of the shaped body. First, the portion other than the molten glass contact portion is more likely to be deformed in a direction away from the molded body. The deformation of the metal plate in the direction of the heat is generated along the surface of the formed body due to =^. Thereby, the molten glass is suppressed, and the thermal expansion is absorbed, so that the deformation of the contact surface of the county surface away from the molded body is suppressed. In the overflow down-draw method disclosed in Patent Document 2, for example, a noble film such as molybdenum is formed on the surface of the molded body which is in contact with the molten glass. In the overflow down-draw method disclosed in Patent Document 3, for example, a metal plate of platinum or a platinum alloy is disposed at a lower end portion of the molded body. PRIOR ART DOCUMENT Patent Document 4 201236984 1 : Japanese Patent Unexamined 5] Na No. 6 Gazette Search for Document 3: Japan's True Brake M However, the patent literature! ^ _81653 STATEMENT It is understood that the entire molded body is covered as shown in the case where the metal plate portion is continuous on the formed body. In the case of contact with the glazed glass of 1 =, there is a case where the surface of the body is thermally expanded. b The continuous molded body at the contact portion of the glazed glass begins to thermally apply stress, which may also be on the frequency. Cracks are generated. Further, in the same manner as the method disclosed in the patent document, the noble metal film thermally expands from the molded body due to the heat of the molten glass, whereby the noble metal film may leave the molded body. The direction is deformed or it is possible to cause cracks in the formed body. Further, when a metal plate different from the molded body is disposed at the lower end portion of the molded body as in the method disclosed in Patent Document 3, the lower end portion of the molded body is a portion where the molten glass is integrated and integrated. It has an adverse effect on the surface accuracy of the slab glass. In view of the above, the present invention has a technical problem in that, in the case where the molded body is coated with a metal in order to suppress the elution of the components of the molded body to the molten glass by the overflow method, the method of the invention is to reduce the thickness of the molded body to 201236984 41494pif. In the case where the coated metal is deformed or the molded body is cracked, the surface precision of the formed sheet glass can be favorably maintained. The sheet glass manufacturing apparatus of the present invention created to solve the above problems includes a formed body having an overflow groove at the top and having a pair of outer sides formed on both sides of the overflow groove and connected to each other at a lower end a molten glass flows into the overflow groove, and the molten glass overflowing from the overflow groove is melted along the pair of outer side faces and merged at the lower end of the pair of outer side faces to form Plate glass; Laisong of the plate glass manufacturing apparatus: a coating portion containing a metal is provided only on the inner surface of the overflow groove in the surface of the collision. When the molded body is in contact with the molten glass, in consideration of the fact that the molded body component is eluted into the molten glass, the temperature of both of them is large, in addition to the chemical composition of both, and the time of contact between the two. The material at the interface between the molten glass and the temperature of the molded body is increased, and the dissolution of the molded body component into the molten glass is increased. On the surface of the molded body, the inner surface of the groove is overflowed, and the inner surface of the groove is the portion where the molten glass is first contacted, so that the temperature is the highest. Since the molded body component is eluted from the inner surface, it is highly likely to be eluted in the molten glass. In the above apparatus, since the inner surface is covered by the coating portion containing metal, it is possible to effectively suppress the elution of the molded body component into the molten glass. On the other hand, the surface other than the inner surface of the overflow groove in the molded body is covered with the covering portion containing the metal, and the covering portion is a part of the molded body, and the surface area thereof is small. Therefore, in the case where the metal of the covering portion due to the heat of riding the glass and the frequency of the forming portion are swollen in the direction along the surface, the difference between the two is limited. Therefore, it is possible to suppress the deformation of the object in the direction of the object in the direction of the pan: the Ϊαλ" device, since the surface of the outer surface portion of the molded body is not covered by the covering portion of the metal of the package 3, the surface is not generated. Deformation of the metal in the direction away from the shaped body or cracking of the formed body due to thermal expansion. Therefore, the surface has a good dimensional accuracy in the sheet glass as compared with the case where it is covered with a metal. The surface of the glass is fused to flow down, so that the surface precision of the formed sheet glass can be favorably maintained. In the above apparatus, it is preferable that the covering portion is provided in a range of 80% or more of the inner surface of the overflow groove. According to this, it is possible to sufficiently enjoy the effect of suppressing dissolution of the molded body component into the molten glass. In any of the devices, it is preferable that the energization by the above-mentioned covering portion is not performed. According to this, it is easy to suppress the elution of the molded body component into the molten glass on the surface of the molded body in the vicinity of the covering portion. In the above apparatus, it is preferable that the covering portion is a metal film formed by splattering. When the metal of the coating portion is in the form of a metal film, it can be formed directly on the surface of the y-shaped body, and the metal in the form of a plate can be fixed by molding or the like, and the surface can be easily formed on the surface of the body. On the other hand, when the metal film is formed by spraying, the film formation is fast and the heat applied to the molded body is less than that of the molded body. Therefore, deformation or strain of the molded body 201236984 41494pif due to film formation can be suppressed. The type of the spray is not particularly limited, and examples thereof include flame spraying, plasma spraying, and the like. In any of the above devices, it is preferable that the covering portion is formed of platinum or a platinum alloy. According to this, even when the temperature of the molten glass exceeds 1 Torr (rc), the metal of the coating portion is hardly melted. Examples of the platinum alloy include a platinum-rhodium alloy, a silver alloy, and the like. It is preferable that the thickness of the metal film is 5 〇 to 1000 μm, and if the thickness of the metal film as the covering portion is 5 〇 μm or more, peeling or cracking of the metal film which occurs during the molding of the sheet glass can be suppressed. When the thickness of the metal film of the coating portion is less than or equal to the following, cracking or peeling on the metal film side during the refining can be suppressed. Further, in the case of forming the sheet glass, the month b is prevented from being obstructed by the metal film due to the flow of the molten glass. A method for producing a sheet glass of the present invention which is created to solve the above problems, comprising a molded body having an overflow groove at the top and having an opening a pair of outer sides of the overflow groove connected to each other at the lower end, the molten glass flows into the overflow groove, and the molten glass overflowing from the overflow groove The sheet glass is formed by being fused and integrated at a lower end of the pair of outer side surfaces along the pair of outer side surfaces, and the sheet glass manufacturing method is characterized in that the above-mentioned overflow is used only in the surface of the formed body. The inner surface of the groove is provided with a molded body including a metal coating portion. 8 201236984 • The configuration of the side method is substantially the same as the configuration of the apparatus described above in the sheet glass manufacturing apparatus of the present invention, and thus the effect and effect thereof are According to the present invention, in the case of suppressing the elution of the components of the molded body into the molten glass, the molded body is coated with the metal by the overflow down-draw method. In the case where the coated metal is deformed or the molded body is cracked, the surface precision of the formed sheet glass can be favorably maintained. [Embodiment] Hereinafter, the form for carrying out the invention will be described based on the drawings. 1A is a schematic front view showing a main part of a sheet glass manufacturing apparatus according to an embodiment of the present invention. As shown in Fig. 1A, the thin plate glass manufacturing apparatus includes a molded body 1 for performing an overflow down-draw method. The molded body 1 is as shown in Fig. 1A along the width direction of the thin plate glass to be manufactured. The direction is an elongated shape, and the following components are main components: the overflow groove 2 formed along the longitudinal direction of the top portion extends from the upper end edge to the top flat portion 3 of the molded body 1 on the outer side, and A pair of outer side faces 4 which are gradually approached to each other in a wedge shape. The lower end portion of the formed body 1 is referred to as a bottom portion 5, and the lower ends of the outer side faces 4 on both sides of the formed body 1 are The molded body 1 is formed of, for example, an alumina refractory, an oxidized refractory, or the like having corrosion resistance with respect to the molten glass g. The molded body 1 of the present embodiment is provided with a guide 6. Piece 6 contains the inscription or its alloy' and is disposed at both ends of the length of the two outer side faces 4 and the bottom 5 in the direction of 201236984 41494pif. The guide member 6 extends from the overflow groove 2 of the molded body 1 to the top flat portion 3, the both outer side faces 4, and the bottom portion 5, and has a function of defining the width of the molten glass g flowing down. A supply pipe 7 that supplies the molten glass g is connected to one end side in the longitudinal direction of the overflow groove 2. In the present embodiment, the overflow groove 2 has a V-shaped cross section with the flow path bottom plate 8 as a lower jaw. The flow path bottom plate 8 of the overflow groove 2 is inclined in such a manner as to gradually become higher as it moves toward the end portion side from the start end side in the flow direction of the molten glass bowl g. The inner surface of the overflow groove 2 is covered by the metal film 9 as a coating portion formed by spraying, and on the other hand, all the blanks on the surface of the top flat portion 3 and the outer surface portion 4 are exposed. The portion of the film of the metal film 9 may be at least a part of the inner surface of the overflow groove 2, and in the present embodiment, it is 80% of the inner surface of the overflow groove 2, but may be 80% or more. Further, as shown in Fig. 1B, in the present embodiment, the flow path bottom plate 8 is included, and the metal film 9 is continuously covered from the flow path bottom plate 8 of the overflow groove 2 toward the upper end. The distance between the upper end of the metal film 9 and the upper end of the overflow groove 2 is fixed in the extending direction of the overflow groove 2. Moreover, the distance is the same on the opposite side of the overflow groove 2. In the present embodiment, the material of the metal film 9 is platinum, but it may be a platinum alloy. Further, in the present embodiment, as the film forming method, flame spraying may be used, and other spraying such as plasma spraying may be used. Further, the metal film 9 can be formed by a method other than the spraying such as vapor deposition or the like. Further, for the sake of easy understanding, the metal film 9 is illustrated to be thicker than actual. The thickness of the metal film 9 is, for example, 5 〇 μηη to 1 μm μη, preferably μιη to 500 μηι, and in the present embodiment, 25 μm μηη. If the thickness of the metal film is less than 50 μm at 201236984, peeling or cracking of the metal film $ may occur during the forming of the sheet glass, or corrosion of the metal film 9 caused by the molten glass g may occur. If the thickness of the metal film 9 exceeds 1 μm, cracking or peeling may occur on one side of the metal film 9 at the time of spraying. Further, when the thickness of the metal film 9 exceeds 1000 μm, the metal film 9 hinders the molten glass g from maneuvering during the molding of the sheet glass, thereby causing a bad view to the surface precision of the formed sheet glass. Further, in consideration of the surface precision of the formed sheet glass, it is preferable that the thickness of the metal film 9 is uniform in the sheet width direction. Hereinafter, a method of manufacturing the sheet glass using the above apparatus will be clarified. First, a raw material of glass such as an alkali-free glass (for example, 〇A_1〇G manufactured by Nippon Dentiscopis Co., Ltd.) is melted in a glass melting furnace (not shown). Next, the molten glass g is caused to flow into the overflow groove 2 of the forming body 1 via the supply pipe 7. When the molten glass g flows into the overflow groove 2 by a predetermined amount, the molten glass g flows down from the overflow groove 2 through the top flat portions 3 on both sides thereof along the outer side surface portions 4. This molten glass g is fused and integrated at the bottom 5 of the molded body 1. The integrated molten glass g is continuously formed into a sheet glass by being pulled by a pulling mechanism (not shown) provided by a lower roller or the like and cooled. In the sheet glass manufacturing apparatus of the present embodiment configured as described above, the following effects can be obtained. Since the inner surface of the overflow groove 2, which is highly likely to be dissolved in the molten glass g by the molded body component, is covered by the first metal film 9, it is possible to effectively suppress the elution of the bulk component into the molten glass g. On the other hand, the surfaces of the top flat portion 3 and the outer surface portion 4 of the molded body i are not covered by the metal film 9, and the portion where the metal film 9 is covered is a portion on the molded body, and the surface area thereof is small. Therefore, in the heat of the secret glass g, the metal film 9 and the molded body are __ tracked in the direction along the surface, and the difference between the two is limited. Therefore, deformation of the metal film 9 in the direction away from the molded body 1 or cracking of the molded body i due to thermal expansion can be suppressed. Further, since the surface of the outer surface portion 4 of the molded body 1 is not covered by the metal film 9, the silk surface does not undergo deformation due to the heat of the (four) glass g and the metal film 9 thermally expands and leaves the molded body 1, or From the metal film 9 攸 formed body 1, thermal expansion (four)_cracking occurs. Therefore, the surface precision of the surface of the sheet glass is favorably maintained as compared with the case where the surface is covered with the metal film 9. Since the surface is a portion where the glass is merged and melted before the body is melted, the surface precision of the glass is well maintained. Further, in the above-described embodiment, the face 4 is white (the single face is a single plane), but the present invention is not limited thereto. For example, as shown in the figure, each of the outer face portions 4 may also be associated with the vertical face. The inclined night 4b is connected up and down. That is, at least the lower side portion of the outer side surface 4 is gradually closer to each other and the lower end thereof is connected to each other, and the bottom portion 5 of the saddle body 1 is sufficient. In the above embodiment, The overflow groove 2 has a V-shaped cross section, but the present invention is not limited thereto. For example, as shown in Fig. 2, the cross section may have a rectangular shape or a U-shape. 12 201236984 Further, the above embodiment The inner surface of the overflow groove 2 is covered by the metal film 9 formed by spraying, but the present invention is not limited thereto, and the metal film 9 may be formed by a method other than welding. The inner surface of the groove 2 may be covered with a metal member such as a metal plate without the metal film 9. The present invention is not limited to the above description, and various modifications may be made within the scope of the technical idea. Description] Figure 1A shows the hair FIG. 1B is a view showing a main part of a sheet glass manufacturing apparatus according to an embodiment of the present invention, and is a front view of the XX line of FIG. 1A. Fig. 2 is a cross-sectional view showing another example of the present invention. [Description of main component symbols] 1 molded body 2 overflow groove 3 top flat portion 4 outer side surface 4a: vertical surface portion 4b: inclined surface portion 5: bottom portion 6: guide Primer 7: supply pipe 8: flow path bottom plate 13 201236984 414y4pif 9 : metal film (covered portion) g: molten glass 14