JP2016051821A - Manufacturing method of glass substrate, and manufacturing device of glass substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a glass substrate that can achieve both stable conveyance and washability of the glass substrate.SOLUTION: There is provided a manufacturing method of a glass substrate including a glass substrate for a liquid crystal display and a substrate floating unit that floats to convey the glass substrate, the method including: a floating step of forming a liquid layer comprising a liquid between a bottom face of the glass substrate and the substrate floating unit so as to maintain a constant pressure in a surface direction on the glass substrate, supplying and recovering the liquid to circulate the liquid, and controlling the pressure or the amount of supplying and recovering the liquid to set the height of the liquid layer and float the glass substrate on the liquid; and a conveyance step of applying an external force in the surface direction to the glass substrate to convey the glass substrate on the liquid.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a glass substrate manufacturing method and a glass substrate manufacturing apparatus.

  A flat glass plate is used as a display part of a display such as a liquid crystal display device or a plasma display device. In the following description, such a glass plate is referred to as a glass substrate for a flat panel display or simply a glass substrate. For example, in a liquid crystal display device, a moving image can be displayed by changing the electric field applied to the liquid crystal sealed between the glass substrates and changing the orientation of the liquid crystal. Since it is necessary to change the electric field when displaying an image on the liquid crystal display device, a transparent electrode for applying a voltage is formed on the glass substrate.

  In addition, an active matrix using thin film transistors (TFTs) is used in liquid crystal display devices used in television receivers that require high-quality display in order to control the on / off of the voltage applied to the electrodes on the glass substrate. System control is adopted. This TFT is also formed on the glass substrate. Specifically, a liquid crystal display includes a TFT (Thin Film Transistor) that controls the amount of transmitted light, a liquid crystal, and a color filter as components. A method for manufacturing a color filter panel in a liquid crystal display usually forms a black matrix on the surface of a glass substrate, and then sequentially forms different hues of red, green, and blue in a striped or mosaic color pattern. Method is used.

  As the display becomes higher in definition, the line width and pitch of the black matrix arranged on the surface of the glass substrate are reduced. For example, in order to achieve a high contrast of the display, the aperture ratio is improved by increasing the fineness and definition of the black matrix (specifically, the line width of less than 20 μm) and the high dimensional accuracy of the black matrix. There is a need for improved light shielding. As the number of display pixels increases, the pattern size varies depending on the use of the color filter and each color. For example, red, green, and blue pixels are changed from 200 to 300 μm to 100 μm, and the black matrix is 20 μm. Fine wire technology has been developed from 10 μm to 5 μm.

  As described above, electrodes and active elements are formed by a very thin metal film or semiconductor on the glass surface of a glass substrate for a flat panel display. Therefore, the glass surface of the glass substrate has extremely high flatness and extremely high cleanliness. Sex is required.

  By the way, if the glass substrate for flat panel displays is what is used for a liquid crystal display device (henceforth a liquid crystal glass substrate), it will exhibit a thin rectangular plate-like form. The glass substrate for liquid crystal is usually about 0.05 mm to 0.7 mm and thinner than 1 mm, and the demand for larger size is increasing year by year.

  The glass substrate for liquid crystal is supplied to the manufacturing process of the liquid crystal display device in a form called mother glass having a size corresponding to the size of a plurality of glass substrates having a size required for one liquid crystal display device. The size of the mother glass is conventionally expressed as a generation, and for example, the size of the sixth generation mother glass is 1500 mm × 1850 mm. The mother glass is obtained by cutting a glass plate formed into a plate shape into a predetermined size. And in order to remove the stain | pollution | contamination, chip, etc. which were produced at the time of the cutting | disconnection of a glass plate, washing | cleaning of the glass substrate for liquid crystals which is mother glass is needed.

  In the conveyance at the time of cleaning the glass surface of the glass substrate for liquid crystal performed in such a situation, a conveyance method using a conveyance roller is widely used. As an example of a transport method using a transport roller, for example, a method described in Patent Document 1 has been proposed. With regard to the cleaning of the glass substrate transported by such a transport system, the glass substrate is cleaned by physical cleaning, or the glass substrate is cleaned by a cleaning unit that applies a striking force to the glass.

JP 2008-285243 A

  However, in the conventional glass conveyance method, as the thickness of the glass substrate becomes thinner, the influence of the bending of the glass substrate becomes larger, and the glass substrate gets under the conveyance roller when the conveyance roller is transferred. was there. In particular, as the thickness of the glass substrate is reduced, the bending phenomenon becomes more prominent. When the thickness of the glass substrate is 0.4 mm or less, the distance between the commonly used transfer rollers is problematic. Therefore, measures such as narrowing the distance between the conveying rollers are taken. If the conveyance roller interval is narrowed, even a thin glass substrate can be stably conveyed, but the place where a cleaning unit for cleaning the glass substrate can be arranged is limited. It may not be possible to ensure cleanability.

  Then, an object of this invention is to provide the manufacturing method of a glass substrate and the manufacturing apparatus of a glass substrate which can make the stable conveyance and cleaning property of a glass substrate compatible.

One aspect of the present invention is a method for producing a glass substrate comprising a glass substrate for a liquid crystal display and a substrate floating unit that floats to convey the glass substrate,
Forming a liquid layer made of liquid between the bottom surface of the glass substrate and the substrate floating unit so that the pressure in the surface direction of the glass substrate is constant, and circulating the liquid while supplying and collecting the liquid; By controlling the pressure or amount to be supplied and recovered, the height of the liquid layer is set, and a levitation step of levitating a glass substrate on the liquid;
A transfer step of applying an external force in the surface direction of the glass substrate and transferring the glass substrate on the liquid,
It is characterized by that.

Cleaning means for cleaning the glass substrate is disposed above and / or below the thickness direction of the glass substrate,
The liquid is a cleaning liquid for cleaning the glass substrate,
It is preferable that the height of the liquid layer is set so that the surface of the glass substrate is cleaned by the cleaning means.

  The thickness of the glass substrate is preferably 0.4 mm or less.

Another aspect of the present invention is a glass substrate manufacturing apparatus including a glass substrate for a liquid crystal display, a substrate floating unit that floats to transport the glass substrate, and a transport unit.
The substrate floating unit forms a liquid layer composed of a liquid between the bottom surface of the glass substrate and the substrate floating unit so that the pressure in the surface direction of the glass substrate is constant, while supplying and recovering the liquid Circulating and controlling the pressure or amount to supply and recover the liquid, thereby setting the height of the liquid layer, and floating the glass substrate on the liquid,
The transport unit applies an external force in the surface direction of the glass substrate, and transports the glass substrate on the liquid.
It is characterized by that.

  According to this invention, even if it is a thin glass substrate, the stable conveyance of a glass substrate and washability can be made compatible.

It is a flowchart for demonstrating the outline | summary of the manufacturing method of the glass substrate of this embodiment. It is the schematic of a single wafer cleaning apparatus. It is a top view of a washing unit. It is a side view of a washing unit. It is a partial enlarged side view of a substrate floating unit. It is a side view of the washing unit concerning Embodiment 2.

<Composition of glass sheet>
A glass sheet (glass substrate) is glass used for manufacture of flat panel displays (FPD), such as a liquid crystal display, for example. In this glass sheet, a color filter is formed by arranging a black matrix and RGB pixels as wavelength selection elements that transmit red (R), green (G), and blue (B) light on the surface. The The black matrix improves display contrast by blocking light leakage of the backlight outside the RGB pixel region and preventing color mixing of adjacent RGB pixels. That is, the light passage region in the color filter is determined by the shape and arrangement of the black matrix. The thickness of the glass sheet is, for example, 0.1 mm to 0.7 mm, and may be 0.4 mm or less. The size of the glass sheet is, for example, 680 mm × 880 mm (G4 size), 2200 mm × 2500 mm (G8 size).

The glass sheet used for the production of FPD is preferably alkali-free glass or fine alkali glass. When the glass sheet is non-alkali glass, the composition of the glass is, for example, SiO ₂ : 50 mass% to 70 mass%, Al ₂ O ₃ : 0 mass% to 25 mass%, B ₂ O ₃ : 1 mass% to 15 mass%, MgO: 0 mass% to 10 mass%, CaO: 0 mass% to 20 mass%, SrO: 0 mass% to 20 mass%, BaO: 0 mass% to 10 mass%. Here, the total content of MgO, CaO, SrO and BaO is 5% by mass to 30% by mass.

When the glass sheet is a fine alkali glass containing a trace amount of alkali metal, the composition of the glass further contains 0.1% by mass to 0.5% by mass of R ′ ₂ O, preferably 0.2% by mass. % To 0.5% by mass of R ′ ₂ O. Here, R ′ is at least one selected from Li, Na and K. The total content of R ′ ₂ O may be less than 0.1% by mass.

Further, the glass sheet, in addition to the above _components, SnO 2: 0.01 wt% to 1 wt% (preferably 0.01 mass% to 0.5 _{mass%), Fe 2 O 3:} 0 wt% 0.2% by mass (preferably 0.01% by mass to 0.08% by mass) may be further contained, and in consideration of environmental load, As ₂ O ₃ , Sb ₂ O ₃ and PbO are substantially contained. It does not have to be contained.

<Flow of glass sheet manufacturing method>
FIG. 1 is a flowchart showing a flow of a glass sheet manufacturing method. Hereafter, each step S1-S10 of a flowchart is demonstrated.

  First, in step S1, a molten glass is generated by heating a glass raw material adjusted to produce a glass sheet having the above-described composition, and a molten glass or preform glass is formed by a downdraw method, a redraw method, a float method, or the like. A glass ribbon having a predetermined thickness is continuously formed. In step S2, the glass ribbon produced | generated by step S1 is cut | disconnected, and the base plate glass which has a predetermined size is obtained. In step S3, the base glass obtained in step S2 is placed on a pallet for transporting and storing the base glass as a laminated body laminated via a slip sheet for protecting the surface of the base glass. .

  Next, in step S <b> 4, the base glass is taken out from the base glass stack, and the base glass is cut into the size of the glass sheet as a product. In step S5, the glass sheet obtained in step S4 is subjected to end face processing such as grinding and polishing of the end face and etching of the end face.

  Next, in step S6, the glass sheet is washed while being conveyed. In the glass sheet cleaning step, cullet, dust, dirt, adhesive foreign matter, and the like, which are fine glass pieces, attached to the surface of the glass sheet are removed. Further, in the glass sheet cleaning step, an inorganic alkaline cleaning agent containing a surfactant is used so that these foreign substances do not adhere to the surface of the cleaned glass sheet again.

  Next, in step S7, an optical inspection of the glass sheet cleaned in step S6 is performed. In step S8, the glass sheet that has passed the inspection in step S7 is placed on a pallet and packed as a laminated body that is alternately laminated with slip sheets for protecting the surface of the glass sheet. In step S9, the packaged glass sheet laminate is shipped to the FPD manufacturer's delivery destination. Pulp paper that does not contain recycled paper is used as the slip sheet sandwiched between the laminates of the glass sheet to be shipped from the viewpoint of preventing foreign matters derived from the slip sheet from adhering to the surface of the glass sheet.

  In addition, the base glass laminated body placed on the pallet in Step S3 may be stored for a long period of several weeks or months in Step S10. In this case, recycled paper is used from the viewpoint of cost and environmental protection as the interleaving paper sandwiched between the laminates of the base glass to be stored. As described above, the laminated body of the base glass that has been stored for a long time is shipped in Step S9 through the cutting process in Step S4 to the packing process in Step S8. In addition, the laminated body of the glass sheet placed and packed on the pallet in step S8 may be stored for a long period of several weeks or months in step S10.

<Flow of glass sheet cleaning process>
Next, the details of the glass sheet cleaning step performed in step S6 of FIG. 1 will be described. In the glass sheet cleaning step, for example, the surface of the glass sheet is cleaned using an inorganic alkaline cleaning agent to which a surfactant is added.

  In the cleaning process, for example, the surface of the glass sheet is cleaned using an inorganic alkaline cleaning agent to which a surfactant is added. The inorganic alkaline cleaning agent is generated by adding an alkali component to a diluted solution obtained by diluting a commercially available glass sheet cleaning solution with water. As the glass sheet cleaning liquid, for example, PK-LCG series manufactured by Parker Corporation or Semi-clean series manufactured by Yokohama Oil & Fats Co., Ltd. is used. More specifically, a cleaning liquid to which p-alkylsulfonic acid is added as a surfactant is used. p-Alkylsulfonic acid is a nonionic surfactant (nonionic surfactant) and is a glass sheet compared to other anionic surfactants (anionic surfactants) such as 1,3-alkylsulfonic acid. Even if it remains on the surface of the black matrix, the black matrix can be prevented from peeling off. Nonionic surfactant does not show ionicity even when dissolved in water, but is a surfactant that exhibits surface activity, and therefore, repulsion by ions is suppressed when forming a black matrix on the surface of a glass sheet. Therefore, the black matrix has good adhesion and excellent cleaning performance. The glass sheet cleaning liquid is diluted with water so as to have a concentration of 1 wt% to 5 wt%, for example. The concentration of the alkaline component in the diluted solution is, for example, 0.02 wt% to 0.15 wt% in terms of the concentration of potassium hydroxide (KOH). The water used for diluting the cleaning agent is pure water subjected to ion exchange treatment, EDI (Electrodeionization) treatment, filter treatment using a reverse osmosis membrane (RO membrane), and decarbonation treatment through a decarbonation device. Ultrapure water is preferable from the viewpoint of keeping the glass sheet surface clean. Moreover, in order to remove soluble organic substances, it is preferable to perform a treatment of passing water through activated carbon. Specifically, foreign substances such as fine particles are removed from the water using a filter, and then organic substances are removed by passing water through activated carbon. Next, ion exchange treatment, EDI treatment, filter treatment using a reverse osmosis membrane, Further, it is preferable to perform a decarbonation gas treatment through a decarbonation gas apparatus. In the ion exchange treatment, ionic substances contained in water, such as chlorine ions and sodium ions, are removed from the water using an ion exchange resin membrane. In the EDI treatment, an ion exchange resin membrane is used, and an ionic substance is removed from water with high accuracy using a potential gradient formed by applying a potential to an electrode. In the filter treatment using a reverse osmosis membrane, ionic substances, salts and organic substances are removed from water. In the carbon dioxide removal treatment, carbon dioxide is removed from water using a carbon dioxide removal device.

In the present embodiment, KOH, NaOH, ETDA-4 are used as dilutions of the glass sheet cleaning liquid.
1 selected from the group consisting of Na, ETDA-4K, Na4P2O7 and K4P2O7
More than one species of alkali component is added to produce a cleaning agent used in the cleaning process. The concentration of the alkaline component of this cleaning agent is 1 wt% or more in terms of the concentration of potassium hydroxide (KOH). The above alkali component has higher etching properties with respect to glass and is more soluble than other alkali components. In particular, it is preferable to use KOH alone as an alkali component from the viewpoint of etching properties, solubility, and prevention of adverse effects on the thin film transistor formed on the glass sheet. Moreover, KOH and NaOH are advantageous in terms of wastewater treatment as compared with other alkali components.

  The cleaning agent used in the cleaning process has a stronger cleaning power for removing foreign substances from the glass sheet as the concentration of the alkali component is higher. However, if the concentration of the alkali component is too high, the glass sheet cleaning device is corroded, causing problems such as generation of crystals in the cleaning agent. Therefore, it is preferable that the concentration of the alkali component of the cleaning agent does not exceed 10 wt%. In order to facilitate handling of the cleaning agent, it is more preferable that the concentration of the alkali component of the cleaning agent does not exceed 5 wt%.

  In this embodiment, there are two types of glass sheet cleaning methods: single wafer cleaning and batch cleaning. Here, a glass sheet cleaning method by single wafer cleaning will be described. FIG. 2 is a schematic view of the single wafer cleaning apparatus 1 for the glass sheet G that performs single wafer cleaning. The single wafer cleaning apparatus 1 includes a cleaning unit 10 that performs a cleaning process. The glass sheet G is cleaned in the cleaning unit 10 with an inorganic alkaline cleaning agent to which a surfactant is added.

  FIG. 3 is a top view of the cleaning unit 10. FIG. 4 is a side view of the cleaning unit 10. As shown in FIGS. 3 and 4, the cleaning unit 10 includes a transport roller 11, a substrate floating unit 12, and a brush unit 13.

  The conveyance roller (conveyance unit) 11 has a plurality of rollers, and conveys the glass sheet G by the plurality of rollers. Each transport roller 11 rotates around the central axis in the same direction at the same speed. Moreover, each conveyance roller 11 is arrange | positioned so that a center axis may be located in a line on the same horizontal plane, and has the same diameter. The conveyance roller 11 is provided in the vicinity of both ends of the glass sheet G so that the glass sheet G is not scratched or soiled when the portion of the glass sheet G that is a product and the conveyance roller 11 come into contact with each other. When the conveyance roller 11 rotates, the glass sheet G that is in contact with the conveyance roller 11 is given an external force in the surface direction to the glass sheet G, and is smoothly and horizontally conveyed at the same speed. By narrowing the interval between the conveying rollers 11 arranged from the upstream side to the downstream side, the force applied to the glass sheet G can be dispersed and the bending of the glass sheet G can be suppressed. If the width is narrowed, a place for installing the brush unit 13 cannot be secured. For this reason, when the glass sheet G is levitated by the substrate levitating unit 12, the force received by the glass sheet G coming into contact with the transport roller 11 is dispersed, and the glass sheet G is prevented from being bent. As shown in FIGS. 3 and 4, for example, by setting the interval between the transport rollers 11 to 70 to 120 mm or more, a brush unit is provided between the upstream transport roller 11 and the downstream transport roller 11. 13 can be provided.

  The substrate floating unit 12 is a unit that floats the glass sheet G by providing a liquid between the lower surface of the horizontal glass sheet G and the substrate floating unit 12. Here, the liquid is arbitrary, for example, water, pure water, ultrapure water, cleaning liquid, or the like. The substrate floating unit 12 is mainly composed of a plurality of float panels that supply liquid. FIG. 5 is an enlarged view of a part of the substrate floating unit 12. As shown in the figure, the substrate floating unit 12 supplies the liquid L to the lower surface (bottom surface) of the glass sheet G so that the substrate floating unit 12 and the glass sheet G do not come into contact with each other. Make it rise. When the thickness of the glass sheet G is 0.4 mm (millimeters) or less, for example, when a force is applied to a part of the glass sheet G, the glass sheet G may be bent. For this reason, even if it is a thin glass sheet G of 0.4 mm or less by supplying the liquid L to the entire lower surface of the glass sheet G and suppressing the force from being applied to only a part of the glass sheet G, The sheet G is conveyed in a state in which the sheet G is kept horizontal without being bent. While the substrate floating unit 12 supplies the liquid, it collects the liquid and controls the height of the liquid surface by controlling the positive pressure and the negative pressure applied to the liquid. Further, the substrate levitation unit 12 controls the supply amount for supplying the liquid and the recovery amount for recovering the liquid, and makes the buoyancy that the liquid gives to the glass sheet G constant, so that the buoyancy that the liquid gives to the glass sheet G. And the gravity of the glass sheet G are balanced, and the glass sheet G is floated on the liquid. By supplying the liquid L to the entire lower surface of the glass sheet G, a liquid layer made of liquid is formed between the bottom surface of the glass sheet G and the substrate floating unit 12 so that the pressure in the surface direction of the glass sheet G is constant. . The substrate floating unit 12 circulates while supplying and recovering the liquid, and controls the pressure or amount for supplying and recovering the liquid, thereby setting the height of the liquid layer and floating the glass sheet G on the liquid. The liquid surface is controlled to a height at which the lower surface of the glass sheet G and the transport roller 11 can come into contact with each other. By rotating the transport roller 11 while the lower surface of the glass sheet G and the transport roller 11 are in contact with each other, the glass sheet is rotated. G is conveyed. The substrate floating unit 12 can stably float the glass sheet G by applying, for example, positive pressure: 0.01 to 0.5 MPa and negative pressure: −10 to 70 kPa to the liquid. As a method for controlling the height of the liquid level while the substrate floating unit 12 supplies and recovers the liquid, a publicly known method can be used, and JP 2004-175525 A and JP 2004-352375 A. Including the contents described in the above, the contents are considered.

  The brush unit 13 has a cleaning brush roll for cleaning the glass sheet G, and one or a plurality of brush units 13 are arranged along the conveyance direction of the glass sheet G. A pair of brush units 13 (above and / or below) are arranged above and below the glass sheet G so that both surfaces of the conveyed glass sheet G can be cleaned. The brush units 13 are arranged so as to cross the conveying direction of the glass sheet G, respectively. A plurality of cleaning brushes are attached to the outer peripheral surface of the cleaning brush roll. The cleaning brush comes into contact with the surface of the glass sheet G to be transported by the shaft rotation of the cleaning brush roll, and the surface of the glass sheet G is cleaned. If the brush unit 13 contacts the glass sheet G in a state where only both ends of the glass sheet G are supported by the transport roller 11, the glass sheet G is bent. In particular, when the glass sheet G becomes thin, the bending due to the contact of the brush unit 13 becomes remarkable. However, in this embodiment, since the whole lower surface of the glass sheet G is supported by the liquid, even if the brush unit 13 is in contact with the glass sheet G, it does not bend. In addition, the brush unit 13 is not limited to the contact washing | cleaning unit which makes a washing brush contact the surface of the glass sheet G, and it wash | cleans by discharging | emitting air and a liquid toward the surface of the glass sheet G. It may be a non-contact cleaning unit for cleaning the surface.

  In the cleaning unit 10 of the present embodiment, the liquid supplied by the substrate floating unit 12 is used as a cleaning liquid, whereby the cleaning liquid is supplied to the surface of the glass sheet G, and the glass sheet G is floated by the cleaning liquid and conveyed. The glass sheet G is washed by 13. The entire lower surface of the glass sheet G is supported by a liquid (here, a cleaning liquid), and no force is applied to a part of the glass sheet G. For this reason, even if the thickness of the glass sheet G is as thin as 0.4 mm or less, the glass sheet G can be conveyed without being bent. Further, since the thin glass sheet G can be washed with the washing liquid and the brush unit 13 while being floated by the liquid and stably conveyed, the washing performance is excellent.

  The cleaned glass sheet G is conveyed downstream by the cleaning unit 10, and a removing process for removing the cleaning liquid adhering to the glass sheet G is performed. In this removal step, the cleaning liquid is removed using a cleaning unit having the same configuration as the cleaning unit 10 described above. The cleaning unit 10 used in the removing process supplies pure water or ultrapure water instead of the cleaning liquid to float the glass sheet G. The cleaning unit 10 floats the glass sheet G with pure water or the like to remove the cleaning liquid adhering to the surface of the glass sheet G with pure water or the like while stably transporting the glass sheet G. The conveying method and the cleaning method of the glass sheet G are the same as the cleaning process.

  The glass sheet G from which the cleaning liquid has been removed is conveyed downstream, and a drying process is performed to remove (dry) pure water attached to the glass sheet G. As a method of drying the glass sheet G, a known method such as a roller having a sponge that absorbs water, an air blowing device that blows air (gas) and blows water can be used. The cleaning process of step 6 includes a cleaning process for cleaning cullet, dust, dirt, sticky foreign matter, etc., which are fine glass pieces adhering to the surface of the glass sheet G, using a cleaning liquid, and adhering to the glass sheet G. The cleaning liquid is removed by using pure water, and the drying process is performed by drying and removing the pure water adhering to the glass sheet G. After passing through these processes, the process proceeds to the inspection process in Step 7. .

  The glass sheet cleaning method by single wafer cleaning has been described above. By such transport and cleaning, the glass sheet can be cleaned while being transported stably, so that both stable transport and cleanability of the glass sheet can be achieved. Moreover, since the glass sheet is floated and transported by the liquid, no force is applied to a part of the glass sheet, so even a thin glass sheet, for example, a glass sheet having a thickness of 0.4 mm or less The glass sheet can be conveyed without being bent. Moreover, since the brush unit which wash | cleans a glass sheet can be provided between an upstream conveyance roller and a downstream conveyance roller, the washability of a glass sheet is securable.

(Embodiment 2)
Next, a method for transporting and cleaning by providing the cleaning unit 10 on both the upper and lower surfaces of the glass sheet G will be described. In addition, description is abbreviate | omitted about the structure which is common in the above-mentioned embodiment.

  FIG. 6 is a side view of the cleaning unit according to the present embodiment. As shown in the figure, the cleaning unit 10 is provided on both the upper and lower surfaces of the glass sheet G to convey and clean. The glass sheet G advances from upstream to downstream in the liquid supplied from the cleaning unit 10 disposed on both sides. Since the liquid (for example, cleaning liquid) is supplied to the both surfaces of the upper surface and the lower surface of the glass sheet G, both surfaces of the glass sheet G are once attached by the pair of brush units 13 provided on both surfaces of the glass sheet G. Can be washed. Moreover, the substrate floating unit 12 provided on both surfaces of the glass sheet G controls the height of the liquid surface on both surfaces of the glass sheet G by controlling the positive pressure and the negative pressure applied to the liquid. The force received by G contacting with the conveyance roller 11 can be dispersed and the glass sheet G can be prevented from bending. By filling the space between the two cleaning units 10 on both sides with a liquid and conveying the glass sheet G in the liquid, an equal force is applied to both sides of the glass sheet G. Even a thin glass sheet G of 4 mm or less can be conveyed without bending.

  As described above, in the glass sheet cleaning method according to the present embodiment, the glass sheet can be cleaned while being stably transported, so that both stable transport and cleanability of the glass sheet can be achieved. Further, since the glass sheet is transported in the liquid, the force applied to the glass sheet is uniform, and more stable transport can be performed.

  The glass sheet (glass substrate) manufactured by this embodiment is suitable as a glass substrate for flat panel displays, for example, a glass substrate for liquid crystal displays or a glass substrate for organic EL displays. Furthermore, the glass substrate manufactured in this embodiment is particularly suitable as a glass substrate for LTPS (Low-temperature poly silicon) TFT display used for high-definition displays, or a glass substrate for oxide semiconductor TFT displays. .

  As mentioned above, although the manufacturing method of the glass substrate and the manufacturing apparatus of the glass substrate of this invention were demonstrated in detail, this invention is not limited to the said embodiment, an Example, etc., In the range which does not deviate from the main point of this invention, it is various. Of course, improvements and changes may be made.

1 Cleaning Device 10 Cleaning Unit 11 Transport Roller 12 Substrate Floating Unit 13 Brush Unit G Glass Sheet L Liquid

Claims (4)

A glass substrate manufacturing method comprising a glass substrate for a liquid crystal display and a substrate floating unit that floats to convey the glass substrate,
Forming a liquid layer made of liquid between the bottom surface of the glass substrate and the substrate floating unit so that the pressure in the surface direction of the glass substrate is constant, and circulating the liquid while supplying and collecting the liquid; By controlling the pressure or amount to be supplied and recovered, the height of the liquid layer is set, and a levitation step of levitating a glass substrate on the liquid;
A transfer step of applying an external force in the surface direction of the glass substrate and transferring the glass substrate on the liquid,
A method for producing a glass substrate, comprising: Cleaning means for cleaning the glass substrate is disposed above and / or below the thickness direction of the glass substrate,
The liquid is a cleaning liquid for cleaning the glass substrate,
The height of the liquid layer is set so that the surface of the glass substrate is cleaned by the cleaning means.
The method for producing a glass substrate according to claim 1. The plate thickness of the glass substrate is 0.4 mm or less,
The manufacturing method of the glass substrate of Claim 1 or 2 characterized by the above-mentioned. A glass substrate manufacturing apparatus comprising a glass substrate for a liquid crystal display, a substrate floating unit that floats to transport the glass substrate, and a transport unit,
The substrate floating unit forms a liquid layer composed of a liquid between the bottom surface of the glass substrate and the substrate floating unit so that the pressure in the surface direction of the glass substrate is constant, while supplying and recovering the liquid Circulating and controlling the pressure or amount to supply and recover the liquid, thereby setting the height of the liquid layer, and floating the glass substrate on the liquid,
The transport unit applies an external force in the surface direction of the glass substrate, and transports the glass substrate on the liquid.
An apparatus for producing a glass substrate.

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