JP3995146B2 - Manufacturing method of glass substrate for liquid crystal display - Google Patents

Description

【００４６】
１００μｍ未満のピット・キズの個数は、比較例１では１６０個であるのに対し、実施例１では５０個だった。したがって、実施例１における１００μｍ以下のピット・キズの個数は、比較例１におけるそれの３分の１以下に減少していることが確認された。また、１００μｍ以上のピット・キズの個数は、比較例１では１０個であるのに対し、実施例１では０個であり、完全にピット・キズの拡大が抑制されていることが確認された。
さらに、両方のガラス基板に偏光板を貼り付け、これを蛍光灯下（照度１×１０³ルクス）で目視観察を行なったところ、本実施例のガラス基板では、ピットの存在が確認されなかったのに対して、比較例１のガラス基板では、数多くのピットが確認された。接着剤はピット径が小さいほどピット中に埋まりやすくなるので、本実験結果から、実施例１のガラス基板は、比較例１のガラス基板に比べて表面の平坦性に優れることが定性的に確認された。
【００４７】
（実施例２）
下記に示す研磨液を１Ｌ調製して、全量を３０℃に設定した恒温槽の中に入れた。次いで下記に示すガラス基板を研磨液の中に３秒浸漬して、研磨液をガラス基板表面に塗布した。その後３０℃で平坦化処理を１０分行ない、続いて水で研磨液を完全に洗浄した。
上記操作を１サイクルとして１０サイクル繰り返した。本実施例におけるガラス基板の研磨量は４００μｍだった。
このようにして作成したＬＣＤ用ガラス基板の表面状態を下記に示す評価法に基づいて評価した。表２に検体数５枚の平均値を示した。
【００４８】
［ガラス基板］
ガラス成分として、ＳｉＯ₂５７％、Ａｌ₂Ｏ₃１７％、Ｂ₂Ｏ₃７％を含むガラス基板（１０ｃｍ×１０ｃｍ角、厚み１１００μｍ）を使用した。
［研磨液］
研磨成分としてフッ酸を、増粘剤として硫酸マグネシウム及びアミン系界面活性剤を、溶媒として水を使用して、フッ酸濃度４０％、硫酸マグネシウム濃度３０％、アミン系界面活性剤濃度１％の研磨液を調製した。
［研磨液の粘度］
Ｂ型粘度計を用いて、ローターＮｏ．４、回転数０．６ｒｐｍ、液温２０℃の条件で研磨液の粘度を測定した。結果は、１×１０³Pa・sだった。
［ガラス基板の表面状態の評価］
表面粗度計を用いて、表面粗さを測定した。また、マイクロメーターを用いて板厚ばらつきを測定した。また、ピット、キズの有無とうねりの有無を目視により観察した。
【００４９】
（比較例１）
下記に示す研磨液を用いた以外は、実施例１と同一研磨量になるように、ＬＣＤ用ガラス基板を作成した。表２に検体数５枚の平均値を示した。
［研磨液］
研磨成分としてフッ酸を、溶媒として水を使用して、フッ酸濃度４％の研磨液を調製した。
［研磨液の粘度］
Ｂ型粘度計を用いて、ローターＮｏ．１、回転数６０ｒｐｍ、液温２０℃の条件で研磨液の粘度を測定した。結果は、１×１０^-1Pa・sだった。
【００５０】
【表２】

【００５１】
実施例２の表面粗さは最大０．００７μｍであるのに対し、比較例２の表面粗さは最大０．０１１μｍであった。また、実施例２の板厚ばらつきは最大５μｍであるのに対し、比較例２の板厚ばらつきは最大１５μｍであった。この結果より、塗布・平坦化・洗浄のサイクルを複数回繰り返して同一研磨量のＬＣＤ用ガラス基板を製造する場合、本発明は、従来技術に比べて、ガラス表面の平坦性が格段に優れることが確認された。また、ピット、キズの有無、うねりの有無についても定性的ではあるが、本発明の方が従来技術よりも優れていることが確認された。
【００５２】
【発明の効果】
以上説明したように、本発明のＬＣＤ用ガラス基板は、従来よりもガラス基板表面の平坦性に優れたものである。また本発明の製造方法によれば、連続生産しても歩留まり良く、かつ化学研磨液の廃棄処分が不要なＬＣＤ用ガラス基板を製造することができる。
【図面の簡単な説明】
【図１】ガラス基板を水平にした状態でＬＣＤ用ガラス基板を製造する場合の製造工程の１実施例を示す正面図である。
【図２】ガラス基板を垂直にした状態でＬＣＤ用ガラス基板を製造する場合の製造工程の１実施例を示す正面図である。
【図３】研磨液を含有する液槽の中にガラス基板を浸漬する塗布手段を用いる場合の表面処理装置の形態を示す模式図である。
【符号の説明】
１ ガラス基板
２ 塗布厚調整ローラー
３ 噴射ノズル
４ 研磨液
５ 洗浄ノズル
６ 水切りワイパー
７ エアーノズル
８ ガラス送り用ローラー
９ 液槽
１０ ガラス固定用カセット
１１ 温度調節用ヒーター[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a glass substrate for a liquid crystal display obtained by chemically polishing a glass substrate with a polishing liquid.ofIt relates to a manufacturing method.
[0002]
[Prior art]
Conventionally, a glass substrate for a liquid crystal display (hereinafter referred to as “LCD”) has been mechanically or chemically surface-treated on the surfaces of the base glass and the laminated glass (hereinafter referred to as “glass substrate”) after film formation. Manufactured.
For example, as a mechanical surface treatment method, the surface of a glass substrate has been polished using abrasive grains as an abrasive. However, in this method, since polishing is performed using an abrasive, there is a problem that the flatness of the surface of the glass substrate is deteriorated. Therefore, in order to solve such problems, fine and soft abrasive grains have been conventionally used. However, in such a surface treatment method, the polishing rate of the surface of the glass substrate is slow and the treatment time is long. There was a point.
[0003]
Furthermore, only one glass substrate can be surface-treated per polishing apparatus, and several stages of polishing processes are required to perform stepwise polishing from roughing to finishing. However, there is also a problem that both the equipment cost and the installation area become large.
[0004]
Further, as a chemical surface treatment method, a planarization treatment has been conventionally performed while immersing a glass substrate in a tank filled with a chemical polishing solution made of several percent hydrofluoric acid. In this method, for example, an area of 1 m²When surface treatment is performed on 50 batches of glass substrates having a length of 1 m × width 1 m and a thickness of 1 mm, the polishing liquid is at least 5.0 m.^ThreeThis polishing liquid is used repeatedly many times after sufficiently controlling immersion conditions such as hydrofluoric acid concentration and temperature.
However, according to the conventional method, as the number of times of processing the glass substrate increases, the flatness of the manufactured glass substrate for LCD gradually deteriorates, and there is a problem that the yield of the product decreases.
[0005]
The present inventor has analyzed this cause, and as a result, it has been found that the decrease in yield is caused by the reaction product generated with the flattening treatment.
That is, when the chemical polishing liquid is used repeatedly, reaction products such as fluoride gradually increase in the chemical polishing liquid. And this reaction product has a property which is easy to adhere or adsorb | suck on a glass substrate. For this reason, when a glass substrate is immersed under the same hydrofluoric acid concentration and temperature conditions, the reaction product adheres to the glass substrate, and the hydrofluoric acid concentration in the polishing liquid remains constant as it is during initial use. The polishing rate gradually deteriorates, and undulations and pits are likely to occur on the substrate surface. Therefore, the flatness of the manufactured glass substrate for LCD is gradually deteriorated and the yield is deteriorated.
[0006]
As for pits on the surface of the glass substrate, for example, pits and scratches with a diameter of 10 μm existing on the substrate surface before the surface treatment expand to a diameter of 10 μm or more, and in severe cases expand to a diameter of 100 μm or more. However, there is a problem that a glass substrate for LCD having excellent flatness cannot be produced. Here, in this specification, the “pit” refers to an irregular recess having a certain width when the glass substrate is observed from directly above. The “pit diameter” means the maximum value of the pit width. For example, when the pit shape is an ellipse, it corresponds to the length of the long axis. In the present specification, “scratch” refers to a linear recess having almost no width when the glass substrate is observed from directly above. The “scratch diameter” refers to the length of the linear portion.
[0007]
Further, when the yield of the LCD glass substrate to be manufactured has deteriorated, it is necessary to discard the entire chemical polishing liquid in the liquid tank and replace it with a new chemical polishing liquid, and the chemical polishing liquid is wasteful.
Furthermore, when the chemical polishing liquid is discarded, the reaction product forms sludge. Therefore, it is necessary to dispose of the polishing component made of hydrofluoric acid and the sludge after separating them. The cost burden was large.
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of various problems that occur in the conventional chemical surface treatment method, and has a glass substrate for an LCD that is superior in flatness of the surface of the glass substrate as compared with the conventional method, and even if it is continuously produced. An object of the present invention is to provide a method for producing a glass substrate for LCD which has a high yield and does not require disposal of a chemical polishing liquid.
[0009]
[Means for Solving the Problems]
  Of the present inventionThe method for producing a glass substrate for LCD includes a polishing component having a function of chemically polishing a glass substrate and a thickening agent having a function of increasing the viscosity of the solution, and a viscosity of 5 × 10. ^-1 ~ 5x10 ⁵ A polishing liquid in the range of Pa · s is applied on a glass substrate by a predetermined amount to advance a flattening reaction of the glass substrate, and after a predetermined time has elapsed, the polishing liquid used for the flattening reaction is washed. And
  According to the present invention, 100 cm²There are no pits with a diameter of 100 μm or more per hit, and there are 50 or less pits with a diameter of less than 100 μm.Can produce glass substrates for LCD. Illuminance 1 × 10³There are no visible pits in LuxCan produce glass substrates for LCD.
[0011]
  As the above polishing liquid, hydrofluoric acid, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acidFromIt is preferable to contain one or two or more selected polishing components, and it is preferable to contain 1 to 55% by weight of the polishing component. In addition, the above polishing liquid is magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium carbonate, magnesium hydroxide, magnesium citrate, magnesium acetate.ofMagnesium compound, ester, phenol, amide, fatty acid ester, phosphate ester, sulfonic acid, nonion, amine, ether, polymer alcoholofSurfactant, anionicofFlocculants, synthetic or natural water-absorbing polymers, polyglycol-based antifoam agents, urea, natural sugars, adhesivesFromIt is preferable to contain one or more selected thickeners.
[0012]
  The polishing liquid preferably contains hydrofluoric acid as a polishing component, and more preferably contains magnesium sulfate and an amine surfactant as a thickener. Further, the above polishing liquid is a fluoride produced by the planarization reaction.ofIt is preferable that the reaction product is substantially not contained. Further, in the step of applying the polishing liquid on the glass substrate, it is preferable to apply the polishing liquid on the glass substrate in a state where the glass substrate is horizontal or vertical.
[0013]
Further, in the step of applying the polishing liquid on the glass substrate, spray coating by spraying, spin coating by a roller, flat coating by a squeegee, or dip coating in which the glass substrate is immersed in a liquid bath containing the polishing liquid is selected. It is preferable to use one type or two or more types of coating means.
In the step of cleaning the polishing liquid subjected to the planarization reaction, it is preferable to use one or more cleaning means selected from shower cleaning, jet cleaning, roller cleaning, and scraper cleaning.
[0014]
Further, in the method for producing a glass substrate for LCD of the present invention, a step of applying a predetermined amount of a polishing liquid on the glass substrate to advance a flattening reaction of the glass substrate, and a flattening reaction after a predetermined time has elapsed. It is preferable to repeat the step of cleaning the polishing liquid a plurality of times.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
An LCD glass substrate with excellent flatness according to the present invention comprises a coating step of uniformly applying a predetermined amount of a polishing liquid containing a polishing component and a thickening agent and having a predetermined viscosity range on a glass substrate. In addition, a flattening treatment process for causing the flattening reaction to proceed for a predetermined time and a cleaning process for cleaning the polishing liquid used in the flattening reaction are manufactured.
In the following, first, raw materials such as a glass substrate and a polishing liquid used in the present invention will be described, and then a coating process, a planarization process, and a cleaning process will be sequentially described.
[0016]
[raw materials]
If the glass substrate used by this invention is a glass substrate normally used for liquid crystal displays, it will not restrict | limit in particular about the component and component composition. For example, in the present invention, SiO in terms of weight%.₂56-60%, Al₂O_Three16-18%, B₂O_ThreeIs preferably used in the range of 7 to 10%.
[0017]
  The polishing liquid used in the present invention is preferably one in which a polishing component and a thickening agent are dissolved in a solvent and both the polishing component and the thickening agent are contained at a constant concentration. Here, the “polishing component” in the present invention refers to a substance capable of polishing the glass substrate surface by a chemical action. As polishing components, hydrofluoric acid, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acidofInorganic acids are preferably used. When it is desired to adjust the polishing rate, two or more of these polishing components can be used in combination.
[0018]
The polishing component concentration is preferably in the range of 1 to 55% by weight, more preferably in the range of 10 to 50% by weight, and particularly preferably in the range of 20 to 40% by weight. If the polishing component concentration exceeds 55% by weight, the polishing rate becomes too high, and the polishing amount is reflected sharply in the processing time, making it difficult to control the thickness of the glass substrate. On the other hand, when the polishing component concentration is less than 1% by weight, the polishing rate becomes too slow and the production rate becomes slow.
[0019]
  In the present invention, the “thickening agent” refers to a substance having an action of increasing the viscosity of the polishing liquid. Thickeners include magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium carbonate, magnesium hydroxide, magnesium citrate, magnesium acetateofMagnesium compound, ester, phenol, amide, fatty acid ester, phosphate ester, sulfonic acid, nonion, amine, ether, polymer alcoholofSurfactant, anionicofFlocculants, synthetic or natural water-absorbing polymers, polyglycol-based antifoaming agents, urea, natural sugars, and adhesives are preferably used. In addition, when it is desired to adjust the viscosity of the polishing liquid, two or more of these thickeners can be used in combination.
[0020]
In the present invention, the “solvent” refers to a substance that serves as a medium for dissolving the above-described polishing component and thickener. In the present invention, water or other water-soluble substances are preferably used as the solvent. Specifically, it is usually sufficient to use only water, but when using a thickener having low solubility in water, a mixed solvent of water and a water-soluble substance such as ethanol can also be used.
[0021]
Next, a method for producing an LCD glass substrate according to the present invention will be described with reference to the drawings. FIG. 1 shows one embodiment of a manufacturing process in the case of manufacturing a glass substrate for LCD in a state where the glass substrate is horizontal.
[0022]
A plurality of glass feeding rollers 8 are installed on the production line, and the glass substrate 1 that performs surface treatment is placed on the glass feeding rollers 8. Above the glass substrate 1, an injection nozzle 3 for spraying the polishing liquid 4 onto the glass substrate, a coating thickness adjusting roller 2 for adjusting the polishing liquid 4 sprayed onto the glass substrate 1 to have a uniform thickness, A cleaning nozzle 5 for cleaning the polishing liquid 4 on the glass substrate 1 subjected to the flattening treatment reaction with cleaning water, a draining wiper 6 for draining the cleaning water remaining on the glass substrate 1, and the draining water is not drained. An air nozzle 7 that completely blows away the remaining cleaning water is disposed at a predetermined position so as to be movable up and down.
[0023]
[Coating process]
First, when the glass feed roller 8 rotates counterclockwise at a constant speed, the glass substrate 1 moves leftward at a constant speed. At this time, the spray nozzle 3 descends to the vicinity of the upper surface of the glass substrate 1, and the polishing liquid 4 is sprayed from the left end to the right end on the glass substrate 1 at a constant speed.
In the present invention, the amount of the polishing liquid 4 sprayed onto the upper surface of the glass substrate 1 is not particularly limited as long as it is a little thicker than the final target coating thickness.
Subsequently, the spray nozzle 3 moves upward and returns to a predetermined position, and the glass feeding roller 8 rotates clockwise, whereby the glass substrate 1 moves rightward and returns to the starting position.
[0024]
Next, when the glass feed roller 8 rotates counterclockwise at a constant speed, the glass substrate 1 moves leftward at a constant speed. At this time, the coating thickness adjusting roller 2 descends to near the upper surface of the glass substrate 1 and rotates clockwise at a fixed position in synchronization with the feeding speed of the glass substrate 1 while maintaining a constant distance from the glass substrate 1. The coating thickness of the polishing liquid 4 is made uniform from the left end to the right end on the glass substrate 1.
Subsequently, the coating thickness adjusting roller 2 moves upward and returns to a predetermined position, and the glass feeding roller 8 rotates clockwise, whereby the glass substrate 1 moves rightward and returns to the starting position. Thereby, the coating process of the polishing liquid 4 is completed.
[0025]
In the present invention, the distance between the coating thickness adjusting roller 2 and the glass substrate 1 is preferably designed to be a distance corresponding to the final target coating thickness. The final coating thickness can be appropriately designed depending on the required polishing amount, the polishing rate of the polishing liquid 4 to be used, etc., but generally the coating thickness adjusting roller 2 is in the range of 0.1 to 3.0 mm. And the distance between the glass substrate 1 may be designed.
[0026]
Here, the polishing liquid 4 applied to the upper surface of the glass substrate 1 is obtained by dissolving a predetermined amount of polishing components and a thickener in a solvent as described above. In the present invention, the temperature is 10 to 40 ° C. The viscosity at 5 × 10^-1~ 5x10^FiveThose within the range of Pa · s are preferred, and 5 to 5 × 10.^FourThose within the range of Pa · s are more preferred, 5 × 10¹~ 5x10^ThreeThose in the range of Pa · s are particularly preferred. Viscosity 5 × 10^FiveIf it exceeds Pa · s, it becomes difficult to adjust the injection amount of the polishing liquid 4 by the application means (in this embodiment, the injection nozzle 3), and further, the polishing liquid by the application means (in this embodiment, the application thickness adjusting roller 2). There is a problem in that the uniformization of the coating thickness 4 is hindered. On the other hand, the viscosity is 5 × 10^-1If it is less than Pa · s, there is a problem in that the uniform coating thickness of the polishing liquid by the coating means (in this embodiment, the coating thickness adjusting roller 2) is hindered.
[0027]
In the present invention, it is very important to keep the coating thickness of the polishing liquid 4 on the glass substrate 1 constant in the above-described coating process. This is because the polishing amount or polishing rate of the outer surface of the glass substrate 1 is proportional to the absolute amount of the polishing component in contact with the upper surface of the glass substrate 1 and the temperature during polishing. In the present invention, by using the polishing liquid 4 having the specific viscosity range described above, the coating amount can be controlled to a certain level even when the glass substrate for LCD is continuously produced.
[0028]
[Planarization process]
After completion of the coating process, the flattening reaction is advanced by leaving the glass substrate 1 for a predetermined time. The time required for this flattening reaction can be appropriately designed according to the required polishing amount, the polishing rate of the polishing liquid 4 used, the reaction temperature, etc., and in general, it is flattened within a reaction time of 1 minute to several tens of minutes. Processing is performed.
[0029]
In the present invention, the polishing rate of the polishing liquid 4 is preferably in the range of 0.5 to 1.2 μm / s, and more preferably in the range of 1.0 to 1.2 μm / s. If the polishing rate exceeds 1.2 μm / s, the polishing rate becomes too high and the polishing amount is reflected sharply in the processing time, making it difficult to control the thickness of the glass substrate. On the other hand, if the polishing rate is less than 0.5 μm / s, the polishing rate becomes too slow, and pits and scratches on the surface of the glass substrate existing on the surface of the glass substrate before the surface treatment are expanded to a diameter of 100 μm or more. There arises a problem that the flattening of the substrate surface is hindered.
[0030]
Further, in the above planarization treatment, reaction products such as fluoride gradually increase as the polishing reaction proceeds. Since this reaction product has a high affinity with the glass substrate 1, it has a property of being easily attached or adsorbed on the glass substrate. For this reason, the contact of the polishing component contained in the polishing liquid 4 with the surface of the glass substrate 1 is generally hindered, and the polishing rate gradually decreases.
However, in the present invention, since the thickener contained in the polishing liquid 4 has a high affinity for the above reaction product, the reaction product can be prevented from adhering to the surface of the glass substrate 1, and the result As a result, generation or expansion of pits on the glass substrate and generation or expansion of scratches can be suppressed.
[0031]
[Washing process]
When the flattening process is completed, the glass feeding roller 8 rotates counterclockwise at a constant speed, so that the glass substrate 1 subjected to the flattening process moves leftward at a constant speed. At this time, the cleaning nozzle 5, the water wiper 6, and the air nozzle 7 are lowered to the vicinity of the upper surface of the glass substrate 1, and the cleaning water is first sprayed from the cleaning nozzle 5 onto the upper surface of the glass substrate 1. The polished polishing liquid 4 is completely cleaned. Next, while the draining wiper 6 is in contact with the upper surface of the glass substrate 1 at a fixed position, the glass substrate 1 is moved leftward, whereby the cleaning water remaining on the upper surface of the glass substrate 1 is drained. Subsequently, air is sprayed from the air nozzle 7 onto the upper surface of the glass substrate 1, whereby the cleaning water remaining on the upper surface of the glass substrate 1 is completely removed and the upper surface of the glass substrate 1 is dried. By performing the above operation from the left end to the right end of the glass substrate 1, the cleaning process is completed.
[0032]
In the present invention, a glass substrate for LCD is manufactured by continuously chemically polishing a large number of glass substrates 1 with the above coating process, planarization process, and cleaning process as one cycle.
According to the coating process of the present invention, the fresh polishing liquid 4 is always supplied to the glass substrate 1. For this reason, reaction products such as fluoride produced by the flattening treatment are substantially not contained in the polishing liquid 4, so that an LCD glass substrate having better flatness than the conventional one is manufactured continuously and with a high yield. be able to.
[0033]
Moreover, when there is much grinding | polishing amount, said cycle can also be repeated in multiple times. In general, the flatness deteriorates as the number of repetitions increases. However, in the present invention, the flatness does not deteriorate even when the number of repetitions increases.
[0034]
In this embodiment, the rotary application means using the application thickness adjusting roller 2 is used. However, the application means of the present invention is not limited to this. For example, spray application by spray, flat application by squeegee, or polishing liquid. A coating means such as dip coating in which a glass substrate is immersed in a liquid tank containing a slag can also be used as necessary.
In this embodiment, shower cleaning by the cleaning nozzle 5 and scraper cleaning by the water wiper 6 are used. However, the cleaning means of the present invention is not limited to this, for example, cleaning such as jet cleaning or roller cleaning. Means can also be used as needed.
[0035]
In addition, the present embodiment shows a manufacturing process in the case where a glass substrate for LCD is manufactured in a state where the glass substrate 1 is horizontal, but in the present invention, the glass substrate 1 may be manufactured vertically. Yes (see FIG. 2). In the embodiment of FIG. 2, the glass substrate 1 is fixed by a support material (not shown) and moved in the vertical direction. At that time, the polishing liquid 4 is sprayed from both the left and right directions of the glass substrate 1, so A process and a cleaning process are performed. When the manufacturing method shown in FIG. 2 is employed, an LCD glass substrate in which the left and right surfaces of the glass substrate 1 are flattened can be manufactured.
[0036]
In this embodiment, the polishing liquid 4 applied to the surface of the glass substrate 1 is flattened in a state where it is held vertically, so that liquid dripping tends to occur due to the influence of gravity. Therefore, in order to prevent such dripping, 5 × 10¹~ 5x10^ThreeIt is preferable to use the polishing liquid 4 in the viscosity range of Pa · s.
[0037]
FIG. 3 is a schematic view showing a form of the surface treatment apparatus in the case of using a coating means for immersing the glass substrate 1 in the liquid tank 9 containing the polishing liquid 4. In the present embodiment, it is preferable to introduce a temperature adjusting heater 11 into the liquid tank 9 to adjust the temperature of the polishing liquid 4 to a constant temperature. In order to make the temperature distribution in the liquid tank uniform, a stirrer may be used in combination.
[0038]
In this embodiment, several glass substrates 1 are fixed to the glass fixing cassette 10, and these are immersed in the polishing liquid 4 stored in the liquid tank 9. The glass substrate 1 is pulled up within 5 seconds after the immersion, and the planarization reaction proceeds with the glass substrate 1 held constant. As described above, the time required for the flattening reaction can be appropriately designed according to the required polishing amount, the polishing rate of the polishing liquid 4 used, the reaction temperature, and the like. Generally, the reaction time is several seconds to several minutes. A flattening process is performed. After the planarization process is completed, the polishing liquid 4 subjected to the planarization process is completely cleaned using the above-described cleaning means, whereby the LCD glass substrate of the present invention is manufactured.
[0039]
In this embodiment, the glass substrate 1 is pulled up immediately after the glass substrate 1 is immersed in the polishing liquid 4. Even in such a simple processing operation, the coating amount of the polishing liquid 4 on the glass substrate 1 can be controlled to a constant thickness by appropriately designing the viscosity of the polishing liquid 4 as described above.
Further, in this embodiment, the polishing liquid 4 is used many times as in the conventional method. However, since the immersion time of the glass substrate 1 is extremely short, the reaction product such as fluoride described above is used as the polishing liquid. Hardly generate in.
Therefore, since the reaction product is not substantially contained in the polishing liquid 4, when the LCD glass substrate is continuously produced using the polishing liquid 4, the flatness of the glass substrate surface is improved as compared with the conventional case. An excellent LCD glass substrate can be manufactured with a high yield.
[0040]
Further, in this embodiment, since the reaction product is substantially not contained in the polishing liquid, there is an advantage that the disposal of the polishing liquid 4 is not required.
Furthermore, as another advantage of this embodiment, in addition to being able to planarize both surfaces of the glass substrate 1, a plurality of glass substrates can be dipped at a time, so that the production rate of the LCD glass substrate of the present invention can be increased. The points that can be raised can be mentioned.
[0041]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited at all by these Examples. In the following examples and comparative examples, “%” means% by weight.
[0042]
Example 1
1 L of the polishing liquid shown below was prepared and put in a thermostatic bath whose total amount was set to 30 ° C. Next, the glass substrate shown below was immersed in a polishing solution for 3 seconds, and uniformly coated so that the coating amount was 0.5 mm.
Thereafter, a flattening treatment was performed at room temperature (25 ° C.) for 2 minutes, and then the polishing liquid was completely washed with water to prepare a glass substrate for LCD. The polishing amount of the glass substrate in this example was 100 μm.
The surface state of the prepared glass substrate for LCD was evaluated based on the evaluation method shown below. Table 1 shows the average value of 10 specimens.
[0043]
[Glass substrate]
As a glass component, SiO₂57%, Al₂O_Three17%, B₂O_ThreeA glass substrate containing 7% (10 cm × 10 cm square, thickness 1100 μm) was used.
[Polishing liquid]
A polishing liquid having a hydrofluoric acid concentration of 30% and a magnesium sulfate concentration of 30% was prepared using hydrofluoric acid as a polishing component, magnesium sulfate as a thickener, and water as a solvent.
[Viscosity of polishing liquid]
Using a B-type viscometer, rotor No. 4. The viscosity of the polishing liquid was measured under the conditions of a rotation speed of 0.3 rpm and a liquid temperature of 20 ° C. The result is 5 × 10²It was Pa · s.
[Evaluation of surface condition of glass substrate]
Using an optical microscope, the substrate 100 cm²The number of pits and scratches with a diameter of 100 μm or more and the number of pits and scratches with a diameter of less than 100 μm were observed. In addition, a polarizing plate is attached to the prepared glass substrate via an adhesive, and this is placed under a fluorescent lamp (illuminance 1 × 10^ThreeLux) was visually observed to observe the presence or absence of pits.
[0044]
(Comparative Example 1)
A glass substrate for LCD was prepared so as to have the same polishing amount as in Example 1 except that the polishing liquid shown below was used. Table 1 shows the evaluation results of the LCD glass substrate prepared.
[Polishing liquid]
A polishing solution having a hydrofluoric acid concentration of 4% was prepared using hydrofluoric acid as a polishing component and water as a solvent.
[Viscosity of polishing liquid]
Using a B-type viscometer, rotor No. 1. The viscosity of the polishing liquid was measured under the conditions of a rotation speed of 60 rpm and a liquid temperature of 20 ° C. The result is 1 × 10^-1It was Pa · s.
[0045]
[Table 1]

[0046]
The number of pits and scratches of less than 100 μm was 160 in Comparative Example 1, whereas it was 50 in Example 1. Therefore, it was confirmed that the number of pits and scratches of 100 μm or less in Example 1 was reduced to one third or less of that in Comparative Example 1. The number of pits and scratches of 100 μm or more was 10 in Comparative Example 1 but 0 in Example 1, and it was confirmed that the expansion of pits and scratches was completely suppressed. .
Furthermore, a polarizing plate is attached to both glass substrates, and this is placed under a fluorescent lamp (illuminance 1 × 10^ThreeIn the glass substrate of this example, the presence of pits was not confirmed, whereas in the glass substrate of Comparative Example 1, many pits were confirmed. The smaller the pit diameter, the easier it is for the adhesive to be embedded in the pit. From this experimental result, it is qualitatively confirmed that the glass substrate of Example 1 is superior in surface flatness to the glass substrate of Comparative Example 1. It was done.
[0047]
(Example 2)
1 L of the polishing liquid shown below was prepared and put in a thermostatic bath whose total amount was set to 30 ° C. Next, the glass substrate shown below was immersed in a polishing liquid for 3 seconds, and the polishing liquid was applied to the surface of the glass substrate. Thereafter, a flattening treatment was performed at 30 ° C. for 10 minutes, and then the polishing liquid was completely washed with water.
The above operation was repeated 10 cycles as 1 cycle. The polishing amount of the glass substrate in this example was 400 μm.
The surface state of the LCD glass substrate thus prepared was evaluated based on the following evaluation method. Table 2 shows the average value of 5 specimens.
[0048]
[Glass substrate]
As a glass component, SiO₂57%, Al₂O_Three17%, B₂O_ThreeA glass substrate containing 7% (10 cm × 10 cm square, thickness 1100 μm) was used.
[Polishing liquid]
Using hydrofluoric acid as the polishing component, magnesium sulfate and amine surfactant as the thickener, and water as the solvent, the hydrofluoric acid concentration is 40%, the magnesium sulfate concentration is 30%, and the amine surfactant concentration is 1%. A polishing liquid was prepared.
[Viscosity of polishing liquid]
Using a B-type viscometer, rotor No. 4. The viscosity of the polishing liquid was measured under the conditions of a rotation speed of 0.6 rpm and a liquid temperature of 20 ° C. The result is 1 × 10^ThreeIt was Pa · s.
[Evaluation of surface condition of glass substrate]
The surface roughness was measured using a surface roughness meter. Moreover, the plate | board thickness dispersion | variation was measured using the micrometer. In addition, the presence or absence of pits and scratches and the presence or absence of undulation were visually observed.
[0049]
(Comparative Example 1)
A glass substrate for LCD was prepared so as to have the same polishing amount as in Example 1 except that the polishing liquid shown below was used. Table 2 shows the average value of 5 specimens.
[Polishing liquid]
A polishing solution having a hydrofluoric acid concentration of 4% was prepared using hydrofluoric acid as a polishing component and water as a solvent.
[Viscosity of polishing liquid]
Using a B-type viscometer, rotor No. 1. The viscosity of the polishing liquid was measured under the conditions of a rotation speed of 60 rpm and a liquid temperature of 20 ° C. The result is 1 × 10^-1It was Pa · s.
[0050]
[Table 2]

[0051]
The surface roughness of Example 2 was a maximum of 0.007 μm, while the surface roughness of Comparative Example 2 was a maximum of 0.011 μm. Further, the plate thickness variation of Example 2 was 5 μm at maximum, whereas the plate thickness variation of Comparative Example 2 was 15 μm at maximum. From this result, when manufacturing a glass substrate for LCD with the same polishing amount by repeating the coating, flattening, and cleaning cycles a plurality of times, the present invention has a remarkably superior flatness of the glass surface compared to the prior art. Was confirmed. Moreover, although it was qualitative also about the presence or absence of a pit and a crack, and the presence or absence of a wave | undulation, it was confirmed that the direction of this invention is superior to a prior art.
[0052]
【The invention's effect】
As described above, the glass substrate for LCD of the present invention is superior in the flatness of the surface of the glass substrate than before. Further, according to the manufacturing method of the present invention, it is possible to manufacture a glass substrate for LCD which has a high yield even in continuous production and does not require disposal of the chemical polishing liquid.
[Brief description of the drawings]
FIG. 1 is a front view showing one embodiment of a manufacturing process for manufacturing a glass substrate for LCD with the glass substrate being horizontal.
FIG. 2 is a front view showing one embodiment of a manufacturing process in the case of manufacturing a glass substrate for LCD in a state where the glass substrate is vertical.
FIG. 3 is a schematic diagram showing the form of a surface treatment apparatus when using a coating means for immersing a glass substrate in a liquid tank containing a polishing liquid.
[Explanation of symbols]
1 Glass substrate
2 Coating thickness adjustment roller
3 Injection nozzle
4 Polishing liquid
5 Cleaning nozzle
6 Drainer wiper
7 Air nozzle
8 Glass feed roller
9 Liquid tank
10 Glass fixing cassette
11 Heater for temperature control

Claims (10)

Both a polishing component having an action of chemically polishing a glass substrate and a thickener having an action of increasing the viscosity of the solution are contained at a constant concentration, and the viscosity is in the range of 5 × 10 ^{−1 to} 5 × 10 ⁵ Pa · s. A glass substrate for a liquid crystal display, wherein a predetermined amount of a polishing liquid is applied onto a glass substrate to cause a flattening reaction of the glass substrate, and the polishing liquid used for the flattening reaction is washed after a predetermined time has elapsed. Manufacturing method. The method for producing a glass substrate for a liquid crystal display according to claim 1 , wherein the polishing liquid contains one or more polishing components selected from hydrofluoric acid, hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid. The method for producing a glass substrate for a liquid crystal display according to claim 1 or 2 , wherein the polishing liquid contains 1 to 55% by weight of a polishing component. The polishing solution, magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium carbonate, magnesium hydroxide, magnesium citrate, magnesium acetate magnesium compound, ester, phenolic, amide, fatty acid esters, phosphoric acid esters, sulfonic acid selected systems, nonionic, amine, ether, surfactant polymeric alcohol, anionic flocculants, synthetic or natural water-absorbing polymers, polyglycol-based defoaming agents, urea, natural sugars, from the adhesive one or process for producing a glass substrate for a liquid crystal display according to any of claims 1 to 3, characterized in that it contains two or more thickeners. Polishing solution contains hydrofluoric acid as a polishing component, a glass for liquid crystal display according to claims 1, characterized in that it contains magnesium sulfate and amine based surfactant as thickeners to claim 4 A method for manufacturing a substrate. Polishing liquid, production of a glass substrate for a liquid crystal display according to any of the preceding claims 1, wherein the reaction product of the fluoride produced by flattening the reaction is equal to or not substantially containing Method. In a state where the glass substrate in a horizontal or vertical, method of manufacturing a glass substrate for a liquid crystal display according to claim 1, claim 6, characterized in applying a polishing liquid onto a glass substrate. By using one or two or more coating means selected from spray coating by spraying, rotational coating by a roller, planar coating by a squeegee, or dip coating in which a glass substrate is immersed in a liquid bath containing a polishing liquid, method of manufacturing a glass substrate for a liquid crystal display according to any one of claims 1 to claim 7, wherein applying a polishing liquid onto the substrate.   The polishing liquid subjected to the planarization reaction is cleaned by using one or more cleaning means selected from shower cleaning, jet cleaning, roller cleaning, and scraper cleaning. The manufacturing method of the glass substrate for liquid crystal displays in any one of 8.   A step of applying a predetermined amount of polishing liquid on a glass substrate to advance a planarization reaction of the glass substrate and a step of cleaning the polishing liquid subjected to the flattening reaction after a predetermined time have been repeated a plurality of times The manufacturing method of the glass substrate for liquid crystal displays in any one of Claims 1-9.

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