A method for effectively reducing bubbles in melting of LTPS glass substrate

Abstract

The present invention relates to a method for effectively reducing bubbles in the melting of LTPS glass substrate, which is composed of the following percentages of oxides: SiO 2 62~65%, Al2O318~22%, CaO 3.9~4.85%, B2O 3 1.5~2%, MgO 4~5%, SrO 5~6.8%, SrCl20.20~0.25%, among which SiO2+Al2O 3 83~84%; the raw materials for SrO are Sr(NO3)2, SrCO3 and SrSO4. The following steps are taken for melting: the raw materials of each component are mixed evenly, melted at a high temperature of 1690~1720℃ for 8~15 hours, the melted and clarified glass liquid is poured into a mold from a platinum crucible to form, and then enters a muffle furnace for precision annealing to obtain LTPS glass. The number of bubbles per unit volume in the LTPS glass of the present invention is significantly better than that of conventional glass, achieving an excellent clarification effect.

Description

Technical Field

[0001] The invention relates to the field of glass manufacturing, and in particular to a method for effectively reducing bubbles in melting of a LTPS glass substrate. Background Art

[0002] The raw materials of TFT-LCD glass substrates do not contain alkali metal compounds and have a high aluminum oxide content, which makes the glass melting process much more difficult than conventional soda-lime silicate glass. The glass melting temperature is high, the viscosity is high, and it is difficult to remove bubbles. The melting and clarification temperature of LTPS (Low Temperature Poly-silicon) glass substrates is about 80~100℃ higher than that of TFT-LCD glass substrates. The batch materials are more difficult to melt, the glass liquid has high viscosity, and bubbles are also difficult to effectively remove, resulting in difficulty in homogenization and clarification processes. In the glass preparation process, bubbles are one of the most common defects, which will affect the appearance, transmittance, mechanical strength and hardness of glass products. When a certain number of microbubbles remain on the glass substrate and the homogeneity is poor, it cannot meet the requirements of display glass substrates. Summary of the invention

[0003] The object of the present invention is to provide a method for effectively reducing bubbles in the melting of an LTPS glass substrate, and to provide an LPTS glass substrate composition and a preparation method thereof.

[0004] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0005] A method for effectively reducing bubbles in the melting of an LTPS glass substrate, characterized in that the composition is composed of the following oxides in mass percentage: SiO2 62-65%, Al2O3 18-22%, CaO 3.9-4.85%, B2O3 1.5-2%, MgO 4-5%, SrO 5-6.8%, SrCl2 0.20-0.25%, wherein SiO2+Al2O3 83-84%;

[0006] Furthermore, the method for effectively reducing bubbles in the melting of LTPS glass substrates is described, wherein the introduced raw materials of SrO are Sr(NO3)2, SrCO3 and SrSO4, and the mass ratio of the three is Sr(NO3)2:SrCO3=4.5~6; SrSO4:[Sr(NO3)2+SrCO3]=5%~8%.

[0007] A method for effectively reducing bubbles in the melting of an LTPS glass substrate, characterized in that the melting is performed by taking the following steps:

[0008] (1) Mix the raw materials of various components uniformly according to the above mass percentages, place them in a high temperature furnace and melt them at a high temperature of 1690-1720°C for 8-15 hours;

[0009] (2) The melted and clarified glass liquid is poured from a platinum crucible into a mold to form;

[0010] (3) Then it enters into a muffle furnace for precision annealing to obtain LTPS substrate glass.

[0011] Beneficial effects of the present invention: The present invention provides a method for effectively reducing glass bubbles in LTPS substrates, so that the number of bubbles per unit volume in the melted sample is significantly better than that of a process formula using conventional glass composition, achieving an excellent clarification effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is the bubble diagram of the melted sample of Example 1;

[0013] Figure 2 This is a bubble diagram of the comparative example melt sample. Implementation

[0014] A method for effectively reducing bubbles in the melting of LTPS glass substrates, the specific implementation steps are as follows:

[0015] The components and contents of the LTPS glass substrate composition used to prepare the LTPS glass substrate composition in Examples 1 to 5 are shown in Table 1:

[0016] The LTPS glass substrate in each embodiment is prepared according to the following steps:

[0017] The raw materials of each component in Table 1 are mixed uniformly, placed in a platinum crucible in a high-temperature furnace and melted at a high temperature of 1690-1720°C for 8-15 hours; when the glass liquid reaches a molten state, the glass liquid is stirred with a platinum stirring rod, and bubbles are more easily discharged, thereby achieving the purpose of clarification and homogenization; the melted and clarified glass liquid is poured from the platinum crucible into a mold for forming; then it is precisely annealed in a muffle furnace, and the obtained glass is cut and polished to obtain an LTPS glass substrate, and the number of bubbles per unit volume in the sample is counted by an optical microscope, and then the quality of the clarification effect is compared. As shown in Table 1, the method provided by the present invention achieves a significant reduction in the number of bubbles compared with the comparative example, such as Figure 1 and Figure 2 shown.

[0018] Embodiment 1~5

[0019] Table 1

[0020]

[0021] The present invention provides a method for effectively reducing glass bubbles in LTPS substrates, so that the number of bubbles per unit volume in the sample obtained by melting is significantly better than that of the process formula using conventional glass composition, and an excellent clarification effect is achieved. To achieve the above-mentioned goal, the key lies in controlling the mass ratio of Sr(NO3)2, SrCO3 and SrSO4, wherein SrSO4 is a glass clarifier, which can release oxygen at high temperature, and its reaction at high temperature is: 2SrSO4== 2SrO+2SO2↑+O2↑, by releasing oxygen at high temperature, and cooperating with the high-temperature evaporation of SrCl2, it can achieve the purpose of clarifying the glass liquid; At the same time, Sr(NO3)2 is also a high-temperature oxygen supply agent, which will also decompose and release oxygen at high temperature, and the temperatures of oxygen release of the two are different. On the one hand, the decomposition product SrO of Sr(NO3)2 and SrCO3 is used in the glass network, which has an important influence on the formation of the silicate network structure. At the same time, the different temperatures of oxygen release of the two are used to discharge bubbles from the glass liquid in stages, so as to achieve the best clarification effect.

[0022] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form; any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the above disclosed methods and technical contents without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A method for effectively reducing bubbles in melting of LTPS glass substrate, characterized in that: The composition for melting LTPS glass is composed of the following oxides in mass percentage: SiO2 62~65%, Al2O3 18~22%, CaO 3.9~4.85%, B2O3 1.5~2%, MgO 4~5%, SrO 5~6.8%, SrCl2 0.10~0.15%, wherein SiO2+Al2O3 83~84%; The following steps are taken for melting: (1) Mix the raw materials of the above-mentioned mass percentages uniformly, place them in a high-temperature furnace and melt them at a high temperature of 1690-1720°C for 8-15 hours; (2) The melted and clarified glass liquid is poured from a platinum crucible into a mold to form; (3) Then enter the muffle furnace for precision annealing at a temperature of 800-830°C to obtain LTPS substrate glass; In the oxide, the raw materials for introducing SrO are Sr(NO3)2, SrCO3 and SrSO4, and the mass ratio of the three is Sr(NO3)2:SrCO3=4.5~6; SrSO4:[Sr(NO3)2 + SrCO3]=5%~8%.

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