1283146 玖、發明說明： 【發明所屬之技術領域】 本發明涉及一種有機發光二極體（以下簡稱OLED)用玻璃基板的研 磨方法，特別涉及一種研磨OLED用玻璃基板，以獲得低光照度的研磨 方法。 【先前技術】 一般情況下，利用OLED的顯示裝置可在15伏特電壓以 下進行驅動，其發光效率高、電消耗少，而且由於不需要 採取TFT-LCD薄膜電晶體工藝，因此其成本不到LCD成本 的一半。同時，由於它本身可以發光，與其他顯示裝置相 比，不僅其視野廣闊，而且具有厚度薄、重量輕、反應速 度快等優點，因此作為新一代的顯示裝置備受關注。這種 利用OLED的顯示裝置具有在玻璃基板上塗，覆有ITO薄膜 ，在ITO薄膜上設有有機發光層的結構特性。 因此，用於OLED的玻璃基板的光照度及平坦度，對利 用OLED的顯示裝置性能產生巨大影響。為了用於製造 OLED，這種玻璃基板首先要經過研磨。 目前通常採用的玻璃基板研磨方法是，利用研磨裝置， 通過相同的研磨劑和研磨墊研磨後，投入到ITO薄膜塗層 等OLED的製造工藝中。 但是，這種研磨方法，僅通過一次研磨就要滿足玻璃基 板的光照度及平坦度，因而難以同時獲得低光照度及平坦 1283146 為此’把ITO薄膜塗覆於玻璃基板上時，會出現波峰（ spike)，從而在驅動〇LED時導致亮度及電效率降低，致使 元件出現不良反應。 【發明内容】 本發明的目的在於解決上述不足，提供一種將〇LED用玻璃基板研磨 成低光照度的OLED用玻璃基板的研磨方法。 本發明的另一目的是，提供一種將玻璃基板研磨成低光照度，並且利用 玻璃基板製造OLED時，可減少不良現象的0LED用玻璃基板的研磨方法。 本發明的又一目的是，提供一種通過研磨低光照度玻璃基板，提高利用 玻璃基板的OLED的電效率及亮度的OLED用玻璃基板的研磨方法。 為了實現上述目的，本發明採取如下技術方案： 本發明OLED用玻璃基板的研磨方法，利用玻璃研磨裝置進行研磨。該 玻璃研磨裝置包括有其上面附著有研磨墊、並向規定方向旋轉的下頂板； 與所述下頂板緊密接觸向下加壓、並在所述下頂板上按規定角度左右盤旋 的上頂板；以及向下頂板供應研磨液的研磨液供應裝置。其研磨方法包括 用包含氧化鈽系列研磨劑的研磨液對玻璃基板進行第一次研磨的階段和用 包含氧化矽系列研磨劑的研磨液，對經過第一次研磨的玻璃基板進行第二 次研磨的階段。 通過所述第一次研磨階段和第二次研磨階段進行研磨 時’所述上頂板的向下壓力發生變化，所述下頂板的轉速 和上頂板的旋轉速度也發生變化，以此進行研磨。通過這 種方法可提高OLED用玻璃基板的平坦度及表面光照度。 所述氧化鈽系列研磨劑為二氧化鈽，所述氧化矽系列研 1283146 - 迴旋驅動裝置5包括：相對於下頂板2沿水平方向支樓上頂板3的支撲 • 臂51 ’為使支撲臂51左右旋轉移動而與支撐臂51的一端連接的旋轉轴52, 以及用於左右移動旋轉轴52的驅動馬達（未圖示）。在此，按照不同的研 磨時間，可分別控制下頂板2的轉速、上頂板3的加壓量及旋轉速度。 研磨液供應裝置6用於向下頂板2的中央及週邊供應研磨液。即，研磨 液供應裝置6在規定位置分開，分別通向上部供應管道61及下部供應管道 62。上部供應管道61附著於支撐臂51的規定位置，向下頂板2的週邊部 分供應研磨液，下部供應管道62與下頂板2的中央部分連通，並向下頂板 • 2的中央部分供應研磨液。 在這種研磨裝置’被研磨的OLED用玻璃基板，通過設置於上頂板3下 面的研磨座附者於上頂板3，上頂板3在下頂板2上左右往復迴旋運行，並 隨著下頂板2的旋轉聯動旋轉。從而，附著於上頂板3的下面的〇LED用 玻璃基板，在附著於下頂板2上面的研磨墊21和研磨液供絲£ 6供應的 研磨液的作用下得到研磨。 - 下賴姻上述研棘置的OLED基板的研磨方法進行說明。圖 2知本伽QLED肖賴魏㈣财法的雜目。如_示，〇LED用 玻璃基板的研財法包括如下轉：第—步，通過具有包含氧化錦系列研 磨劑的研磨液的研磨裝置對玻璃基板進行第一次研磨的階段幻；第二步， 用包含氧化石夕系列研磨劑的研磨液，對經所述第一次研磨的玻璃基板進行 第二次研磨的階段S2。 在第-次研磨階段S1，附著於下頂板2的研磨墊2卜採用多元醇、異氛 ' 认絲面雜劑、催化鮮發糊和與二氧化娜合的雜基甲酸醋 _研磨墊。包含於研磨液的研磨劑為氧鱗（cerium0xide)系府磨劑，包 含有氧_ (Lanthanum Qxide)、氧倾（p_dymium〇xide)、氧化 1283146 鉉（Neodymium 0xide) ’用去離子水⑽水）混合形成。其中，氧 氧化鑭、氧化镨、氧化纽如表丨所示。糾，上軸分的· ' 100nm_150nm。 又馬 【表1】 構 成 氧化 鈽 氧化 鑭 氧 化镨 氧化钕 重 量比 (%) 50-65 30-40 3-8 1-15 利用具備上述條件的研磨墊η和研磨液完成對〇LED用玻璃基板的第 一次研磨。下面對第一次研磨階段S1的研磨條件進行說明。圖$表示本發 明OLED用玻璃基板的研磨方法中第一次研磨時的研磨條件曲線圖。如圖 所不，在第一次研磨階段S1，利用上述研磨裝置進行研磨時，隨著研磨時 間的變化’按各時間段調節上頂板3的加壓及迴旋速度、下頂板2的轉速。 首先，在第一時間段（Ο-A區域），上頂板3的加壓量小，下頂板2的 轉速及上頂板的迴旋速度慢，在這種狀態下按規定時間進行研磨。 其次’在第二時間段（A—B區域），將上頂板3的加壓 力、下頂板2的轉速及上頂板的迴旋速度調節到最高，在這 種狀態下，按規定時間進行研磨。 在第三時間段（B — C區域），保持下頂板2的轉速和上 頂板3的迴旋速度，僅將上頂板3加壓量調節到低於第一時 間段（0 — A區域）的加壓量，在這種狀態下，按規定時間 進行研磨。 在第四時間段（C—D區域），進一步減少上頂板3的加壓 1283146 里，把下頂板2的轉速降低到與第一時間段（〇一 A區域） 的速度相同。同時，把上頂板3的迴旋速度調節為低於（〇 A區域）旋轉速度，在這種狀態下進行規定時間研磨。 在第五時間段（D_E區域），讓上頂板3的迴旋速度保持 不變’進一步減少上頂板3的加壓量及下頂板2的轉速，然 後進行規疋時間研磨，隨後結束研磨。 進行研磨時，通過研磨液供應部6的上部供應管道61和 下部供應管道62供應研磨液。此時，通過上部供應管道61 供應的研磨液量大於通過下部供應管道62供應的研磨液量 〇 通過上述方法進行第一次研磨S1時，在研磨劑和研磨墊 21的作用下，〇LED用玻璃基板的平坦度將降低。即，第一 次研磨階段S1的主要目的在於改善平坦度，而非改善光照 度。 隨後進行OLED用玻璃基板的第二次研磨S2。第二次研 磨階段S2和第一次研磨階段31有所不同。第二次研磨階段 S2中的研磨墊21採用纖維系列的發泡氨基甲酸乙酯。第二 次研磨階段S2的目的是提高玻璃基板的表面光照度，這種 玻璃基板的平坦度已經過第一次研磨階段s丨得到了改善。 因此採用纖維系列的發泡氨基甲酸乙酯。並且，研磨液為 液狀的碎膠和DI水的混合物。在所述第一次研磨階段si， 為了降低玻璃基板的平坦度，採用固態氧化鈽系列研磨劑 與DI水的混合物，但在第二次研磨階段S2中，為了降低玻 璃基板的光照度採用液態研磨劑。分析研磨液分佈，占3 5 1283146 % — 50%重量比的Si02與DI水和其他添加劑混合。此時， 石夕的粒度大小小於70nm— 100nm。 圖4是用顯微鏡拍攝本發明的研磨方法中第一次研磨階 段所研磨的玻璃基板表面的相片。如圖所示，經過所述第 一次研磨階段S1研磨的玻璃基板的表面平坦度可保持在 300 A — 500 A。 採用具備所述條件的研磨墊21和研磨液，完成OLED用 玻璃基板的第二次研磨S2。對第二次研磨階段S2的研磨條 > 件進行說明。圖5是本發明OLED用玻璃基板的研磨方法中 第一次研磨階段的研磨條件曲線圖。如圖所示，第二次研 磨階段S2和第一次研磨階段si—樣，利用上述研磨裝置進 行研磨，並隨著研磨時間的變化，按各時間段調節上頂板3 的加壓量及迴旋速度、下頂板2的轉速。 在第一時間段（0—A區域），在頂板3的加壓力小、下 頂板2的轉速及上頂板3的迴旋速度慢的狀態下，進行規定 時間的研磨。之後，在第二時間段（A_B區域），將上頂 1 板3的加壓量、下頂板2的旋轉速度、上頂板3的迴旋速度 調至最大，並在這種狀態下進行規定時間的研磨。 在第三時間段（B—C區域），保持下頂板2的轉速和上 頂板3的迴旋速度穩定，僅將上頂板3的加壓量調節至與第 一時間段的加壓量相同，並在這種狀態下進行規定時間研 磨。 胃在第四時間段（C—D區域），進一步減少上頂板3的加 壓量，把下頂板2的轉速調節為與第一時間段（〇—a區域 11 1283146 )的轉速相同。並且，降低上頂板3的旋轉速度，使其略 快於第一時間段（〇 — A區域）的旋轉速度。即，使上頂板 3的迴旋速度保持在第二時間段（A — B區域）和第一時間 段（0— A區域）的中間速度。在上述條件下進行規定時間 研磨。 在第五區域（D—E區域），減少上頂板3的加壓量及下 頂板2的轉速、上頂板3的迴旋速度，在此條件下進行規定 時間研磨，並結束研磨。此時，將上頂板3的迴旋速度調 至低於第一區域（0—A區域）的迴旋速度。 第二次研磨階段S2中頂板3的加壓量要低於第一次研磨 階段S1中的值。這是因為第二次研磨階段S2的研磨量少於 第一次研磨階段S1的研磨量，如果上頂板3維持高壓力，就 不能獲得所需要的光照度。但是，下頂板2的轉速或上頂板 3的迴旋速度接近於第一次研磨階段81的速度。 並且’研磨期間的研磨液供應量少於第一次研磨階段S1 的研磨液供應量。第二次研磨階段S2的目的在於提高玻璃 基板的光照度，因玻璃基板表面的研磨量明顯少於第一次 研磨階段S1，因此研磨液的供應量少於第一次研磨。但是 ’就上部供應管道61和下部供應管道62的研磨液供應量而 言，應使通過上部供應管道61的供應量大於通過下部供應 管道的供應量。 圖6表示本發明研磨方法中，用光學顯微鏡拍攝經第二 次研磨階段研磨的玻璃基板表面的玻璃基板表面照片。如 圖所示’在第二次研磨階段S2研磨的玻璃基板的表面光照 12 1283146 度 Rp-v為 30 A — 70 A。 • 採用上述研磨方法，可研磨出低平坦度及低表面光照度 " 的OLED用玻璃基板。 本發明提供一種能夠以低光照度研磨OLED用玻璃基板 的OLED用玻璃基板的研磨方法。 同時，提供一種將玻璃基板研磨成低光照度，並利用這 種玻璃基板製造OLED時，可減少不合格元件的〇LED用玻 璃基板的研磨方法。 • 並且，還提供一種研磨低光照度玻璃基板，提高使用玻 璃基板的OLED的電效率及免度的OLED用玻璃基板的研磨 方法。 【圖式簡單說明】 圖1是本發明OLED用玻璃基板的研磨方法中使用的研磨裝置的示音圖； 圖2是本發明OLED用玻璃基板的研磨方法的流程圖； 圖3是本發明OLED用玻璃基板的研磨方法中進行第一次研磨時的研磨 • 條件曲線圖； 圖4是本發明OLED用玻璃基板的研磨方法中，利用光學顯微鏡拍攝經 第二次研磨的玻璃基板表面的玻璃基板表面照片； 圖5是本發明OLED用玻璃基板的研磨方法中進行第二次研磨時的研磨 條件曲線圖； . 圖6是本發明OLED用玻璃基板的研磨方法中，利用光學顯微鏡拍攝經 第二次研磨的玻璃基板表面的玻璃基板表面相片。 13 1283146 【主要元件符號說明】 1、 本體 2、 下頂板 3、 上頂板 5、 迴旋驅動裝置 51、支撐臂 6、 研磨液供應裝置 61、上部供應管道 11、柵欄 21、研磨墊 4、氣缸 52、旋轉軸 62、下部供應管道1283146 玖Invention Description: [Technical Field] The present invention relates to a method for polishing a glass substrate for an organic light-emitting diode (hereinafter referred to as OLED), and more particularly to a method for polishing a glass substrate for an OLED to obtain a low illuminance . [Prior Art] In general, a display device using an OLED can be driven at a voltage of 15 volts or less, which has high luminous efficiency, low power consumption, and is less expensive than an LCD because it does not require a TFT-LCD thin film transistor process. Half the cost. At the same time, since it can emit light itself, compared with other display devices, it not only has a wide field of view, but also has the advantages of thin thickness, light weight, fast reaction speed, and the like, and thus has attracted attention as a new generation of display devices. Such a display device using an OLED has a structural property of being coated on a glass substrate, covered with an ITO film, and having an organic light-emitting layer on the ITO film. Therefore, the illuminance and flatness of the glass substrate used for the OLED have a great influence on the performance of the display device using the OLED. In order to be used in the manufacture of OLEDs, such glass substrates are first ground. A glass substrate polishing method which is generally used at present is carried out by a polishing apparatus, polished by the same abrasive and a polishing pad, and then placed in an OLED manufacturing process such as an ITO thin film coating. However, this polishing method satisfies the illuminance and flatness of the glass substrate by only one polishing, so that it is difficult to obtain both low illuminance and flatness at the same time. 1283146 For this, when a ITO film is coated on a glass substrate, a peak appears (spike Therefore, when the 〇LED is driven, the brightness and the electric efficiency are lowered, resulting in an adverse reaction of the element. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for polishing a glass substrate for OLED which is obtained by polishing a glass substrate for 〇LED into a low illuminance. Another object of the present invention is to provide a method for polishing a glass substrate for OLEDs which can reduce defects by polishing a glass substrate to a low illuminance and manufacturing an OLED using a glass substrate. Still another object of the present invention is to provide a method for polishing a glass substrate for an OLED which is improved in electrical efficiency and brightness of an OLED using a glass substrate by polishing a low-illumination glass substrate. In order to achieve the above object, the present invention adopts the following technical solution: The polishing method of the glass substrate for OLED of the present invention is performed by a glass polishing apparatus. The glass polishing apparatus includes a lower top plate having a polishing pad attached thereto and rotating in a predetermined direction; an upper top plate which is pressed downward in close contact with the lower top plate and spiraled at a predetermined angle on the lower top plate; And a slurry supply device that supplies the slurry to the top plate. The grinding method comprises the steps of performing a first grinding of the glass substrate with a polishing liquid containing a cerium oxide series abrasive and a second grinding of the first ground glass substrate with a polishing liquid containing a cerium oxide series abrasive. Stage. When the grinding is performed by the first grinding stage and the second grinding stage, the downward pressure of the upper top plate changes, and the rotational speed of the lower top plate and the rotational speed of the upper top plate also change, thereby performing grinding. By this method, the flatness and surface illuminance of the glass substrate for OLED can be improved. The cerium oxide series abrasive is cerium oxide, and the cerium oxide series 1283146 - the gyro driving device 5 includes: a branching arm 51' for supporting the top plate 3 in the horizontal direction with respect to the lower top plate 2 A rotating shaft 52 that is rotatably moved left and right by the arm 51 to one end of the support arm 51, and a drive motor (not shown) for moving the rotating shaft 52 left and right. Here, the rotation speed of the lower top plate 2, the pressing amount of the upper top plate 3, and the rotation speed can be separately controlled according to different grinding times. The slurry supply device 6 is for supplying the slurry to the center and the periphery of the lower top plate 2. Namely, the slurry supply device 6 is separated at a predetermined position, and is connected to the upper supply pipe 61 and the lower supply pipe 62, respectively. The upper supply duct 61 is attached to a predetermined position of the support arm 51, and the slurry is supplied to the peripheral portion of the lower top plate 2, and the lower supply duct 62 communicates with the central portion of the lower top plate 2, and the slurry is supplied to the central portion of the lower top plate 2. In such a polishing apparatus, the glass substrate for OLED to be polished is attached to the upper top plate 3 through a polishing seat disposed under the upper top plate 3, and the upper top plate 3 is reciprocally rotated left and right on the lower top plate 2, and along with the lower top plate 2 Rotate in conjunction with rotation. Thereby, the glass substrate for 〇LED attached to the lower surface of the upper top plate 3 is polished by the polishing pad 21 attached to the upper surface of the lower top plate 2 and the polishing liquid supplied from the polishing liquid supply. - The method of polishing the OLED substrate in which the above-described thorns are placed will be described. Figure 2 shows the miscellaneous of Qiao Qiao QLED Xiao Laiwei (four). For example, the research and development method of the glass substrate for LED includes the following steps: Step-by-step, the stage of the first polishing of the glass substrate by the polishing apparatus having the polishing liquid containing the oxidized series of abrasives; The second polishing step S2 is performed on the glass substrate subjected to the first grinding using a polishing liquid containing a oxidized stone series abrasive. In the first grinding stage S1, the polishing pad 2 attached to the lower top plate 2 is made of a polyol, an ambiguous ray-recognition agent, a catalytic fresh-keeping paste, and a hetero-formic acid vinegar-grinding pad combined with dioxane. The polishing agent contained in the polishing liquid is a cerium 0xide-based abrasive, and includes aerobic _ (Lanthanum Qxide), oxygen pour (p_dymium 〇 xide), and oxidation 1283146 Ne (Neodymium 0xide) 'with deionized water (10) water) Mixed formation. Among them, bismuth oxide, ruthenium oxide, and oxidized ruthenium are shown in the table. Correction, the upper axis is divided into '100nm_150nm. [1] 构成 钸 钸 钸 钸 钸 钕 钕 钕 钕 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 The first grinding. The polishing conditions of the first polishing stage S1 will be described below. Fig. $ is a graph showing the polishing conditions at the time of the first polishing in the polishing method of the glass substrate for OLED of the present invention. As shown in the figure, in the first polishing stage S1, when the polishing is performed by the above-described polishing apparatus, the pressure and the swirling speed of the upper top plate 3 and the number of revolutions of the lower top plate 2 are adjusted for each time period as the polishing time changes. First, in the first period of time (Ο-A region), the amount of pressurization of the upper top plate 3 is small, the rotational speed of the lower top plate 2 and the swirling speed of the upper top plate are slow, and grinding is performed for a predetermined time in this state. Next, in the second period (A-B area), the pressing force of the upper top plate 3, the rotation speed of the lower top plate 2, and the swirling speed of the upper top plate are adjusted to the highest, and in this state, the polishing is performed for a predetermined period of time. In the third time period (B-C area), the rotation speed of the lower top plate 2 and the swirling speed of the upper top plate 3 are maintained, and only the pressing amount of the upper top plate 3 is adjusted to be lower than the first time period (0-A area). The amount of pressure, in this state, is polished for a predetermined period of time. In the fourth time period (C-D area), the pressure of the lower top plate 2 is further reduced by 1283146, and the rotation speed of the lower top plate 2 is lowered to be the same as the speed of the first time period (the area of the first zone A). At the same time, the swirling speed of the upper top plate 3 is adjusted to be lower than the (〇A region) rotational speed, and the predetermined time is polished in this state. In the fifth period (D_E area), the swirling speed of the upper top plate 3 is kept constant, 'the amount of pressurization of the upper top plate 3 and the number of revolutions of the lower top plate 2 are further reduced, and then the time-lapse grinding is performed, and then the grinding is finished. At the time of grinding, the slurry is supplied through the upper supply pipe 61 and the lower supply pipe 62 of the slurry supply portion 6. At this time, the amount of the slurry supplied through the upper supply pipe 61 is larger than the amount of the slurry supplied through the lower supply pipe 62. When the first grinding S1 is performed by the above method, under the action of the abrasive and the polishing pad 21, the LED is used. The flatness of the glass substrate will be lowered. That is, the main purpose of the first grinding stage S1 is to improve the flatness instead of improving the illuminance. Subsequently, the second polishing S2 of the glass substrate for OLED is performed. The second grinding stage S2 differs from the first grinding stage 31. The polishing pad 21 in the second grinding stage S2 is a foamed urethane of a fiber series. The purpose of the second grinding stage S2 is to increase the surface illuminance of the glass substrate, and the flatness of the glass substrate has been improved by the first grinding stage. Therefore, a foamed urethane of the fiber series is used. Further, the slurry is a mixture of liquid gelatin and DI water. In the first grinding stage si, in order to reduce the flatness of the glass substrate, a mixture of solid cerium oxide series abrasive and DI water is used, but in the second grinding stage S2, liquid polishing is used to reduce the illuminance of the glass substrate. Agent. Analyze the slurry distribution, accounting for 3 5 1283146% - 50% by weight of SiO 2 mixed with DI water and other additives. At this time, the particle size of Shi Xi is less than 70 nm - 100 nm. Fig. 4 is a photograph of the surface of a glass substrate polished in the first polishing stage in the polishing method of the present invention by a microscope. As shown, the surface flatness of the glass substrate ground by the first grinding stage S1 can be maintained at 300 A - 500 A. The second polishing S2 of the OLED glass substrate is completed by using the polishing pad 21 and the polishing liquid having the above conditions. The grinding strip > of the second grinding stage S2 will be described. Fig. 5 is a graph showing the polishing conditions in the first polishing stage in the polishing method of the glass substrate for OLED of the present invention. As shown in the figure, the second grinding stage S2 and the first grinding stage si are milled by the above-mentioned grinding device, and the pressing amount and the swirl of the upper top plate 3 are adjusted for each time period as the grinding time changes. Speed, the speed of the lower top plate 2. In the first time period (0-A area), polishing is performed for a predetermined period of time in a state where the pressing force of the top plate 3 is small, the rotation speed of the lower top plate 2, and the swirling speed of the upper top plate 3 are slow. Thereafter, in the second period (A_B area), the pressing amount of the upper top plate 3, the rotation speed of the lower top plate 2, and the turning speed of the upper top plate 3 are adjusted to the maximum, and the predetermined time is performed in this state. Grinding. In the third time period (B-C area), the rotation speed of the lower top plate 2 and the swirling speed of the upper top plate 3 are kept stable, and only the pressing amount of the upper top plate 3 is adjusted to be the same as the pressing amount of the first time period, and In this state, polishing is performed for a predetermined period of time. In the fourth time period (C-D area), the stomach further reduces the amount of pressure applied to the upper top plate 3, and adjusts the rotational speed of the lower top plate 2 to be the same as the rotational speed of the first time period (〇-a area 11 1283146). Also, the rotational speed of the upper top plate 3 is lowered to be slightly faster than the rotational speed of the first time period (〇 - A region). Namely, the swirling speed of the upper top plate 3 is maintained at the intermediate speed of the second period (A - B region) and the first period (0 - A region). Grinding is carried out for a predetermined period of time under the above conditions. In the fifth region (D-E region), the amount of pressurization of the upper top plate 3, the number of revolutions of the lower top plate 2, and the swirling speed of the upper top plate 3 are reduced, and under these conditions, polishing is performed for a predetermined period of time, and the polishing is terminated. At this time, the swirling speed of the upper top plate 3 is adjusted to be lower than the swirling speed of the first region (0-A region). The amount of pressurization of the top plate 3 in the second grinding stage S2 is lower than that in the first grinding stage S1. This is because the amount of polishing in the second grinding stage S2 is smaller than the amount of grinding in the first grinding stage S1, and if the upper top plate 3 is maintained at a high pressure, the required illuminance cannot be obtained. However, the rotational speed of the lower top plate 2 or the rotational speed of the upper top plate 3 is close to the speed of the first grinding stage 81. And the amount of the slurry supplied during the grinding is smaller than the amount of the slurry supplied in the first grinding stage S1. The purpose of the second polishing stage S2 is to increase the illuminance of the glass substrate, since the amount of polishing of the surface of the glass substrate is significantly less than that of the first polishing stage S1, so the supply amount of the polishing liquid is less than that of the first polishing. However, the supply amount of the slurry supplied to the upper supply pipe 61 and the lower supply pipe 62 should be made larger than the supply amount through the lower supply pipe 61. Fig. 6 is a view showing a photograph of the surface of a glass substrate on the surface of a glass substrate polished by a second polishing stage by an optical microscope in the polishing method of the present invention. As shown in the figure, the surface of the glass substrate polished in the second grinding stage S2 is 12 1283146 degrees Rp-v is 30 A - 70 A. • The glass substrate for OLEDs with low flatness and low surface illuminance can be polished by the above grinding method. The present invention provides a polishing method for a glass substrate for OLED which can polish a glass substrate for OLED with low illuminance. At the same time, a method of polishing a glass substrate for 〇LED which can reduce defective components when the OLED is manufactured by using such a glass substrate is provided by polishing a glass substrate to a low illuminance. • Also, a method of polishing a glass substrate for OLEDs by polishing a low-illumination glass substrate and improving the electrical efficiency and freedom of the OLED using the glass substrate is also provided. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a polishing apparatus used in a method of polishing a glass substrate for an OLED according to the present invention; FIG. 2 is a flow chart of a method of polishing a glass substrate for an OLED of the present invention; FIG. 4 is a view showing a polishing/condition chart at the time of the first polishing in the polishing method of the glass substrate; FIG. 4 is a glass substrate on the surface of the glass substrate subjected to the second grinding by the optical microscope in the polishing method of the glass substrate for OLED of the present invention; FIG. 5 is a graph showing the polishing conditions when the second polishing is performed in the polishing method for the glass substrate for OLED of the present invention; FIG. 6 is a second embodiment of the method for polishing a glass substrate for an OLED according to the present invention. Photograph of the surface of the glass substrate on the surface of the sub-polished glass substrate. 13 1283146 [Description of main component symbols] 1. Main body 2, lower top plate 3, upper top plate 5, swing driving device 51, support arm 6, slurry supply device 61, upper supply pipe 11, fence 21, polishing pad 4, cylinder 52 , rotating shaft 62, lower supply pipe