WO2012118651A2

WO2012118651A2 - Glass substrate surface cleaning apparatus and glass substrate surface cleaning method

Info

Publication number: WO2012118651A2
Application number: PCT/US2012/026004
Authority: WO
Inventors: Michihiro Ohishi
Original assignee: 3M Innovative Properties Company
Priority date: 2011-03-01
Filing date: 2012-02-22
Publication date: 2012-09-07
Also published as: JP2012179539A; WO2012118651A3; CN103402657A; JP5840847B2; KR20140014193A; TW201240742A

Abstract

A glass substrate surface cleaning apparatus and method that has a cleaning function that can be applied to foreign matter that exists on glass substrates are provided. The glass substrate surface cleaning apparatus 100 includes a glass substrate support and transport mechanism 20 that supports and transports a glass substrate 50 in a first direction (M in FIG. 3). The apparatus also includes a glass substrate surface cleaning mechanism 10 having a cleaning belt 11 that removes foreign matter 300 adhered to the surface of the glass substrate and that slides on the surface of the glass substrate in a second direction (N in FIG. 3) that intersects the first direction. The cleaning belt includes a plurality of 3 dimensional structured abrasive protrusions 70 and grooves 60 located between the 3 dimensional structured abrasive protrusions. The width 62 of the grooves is wider than the foreign matter adhered to the glass substrate.

Description

GLASS SUBSTRATE SURFACE CLE ANING APPARATUS AND GLASS SUBSTRATE SURFACE CLEANING METHOD

Technical Field

The present invention relates to a glass substrate surface cleaning apparatus and a method of cleaning from a glass substrate surface foreign matter (mainly glass cullet) adhered to the glass substrate surface that is generated in a separation apparatus that separates glass substrates, and more particularly relates to a glass substrate surface cleaning apparatus and method therefore for glass substrates that are used in liquid crystal panels before the application of a polarizing plate in the process of manufacturing liquid crystal panels.

Background

Currently, apparatuses and methods using vacuum suction means on a glass substrate or using abrasives and the like are known cleaning apparatuses and methods for removing foreign matter (mainly glass cullet) adhered to glass substrates and are associated with substrate separation apparatuses that separate glass substrates (for example, Japanese Unexamined Patent Application Publication Nos. 2008-94690 and 2005-81297.

Summary

The problem to be solved by the present invention is to provide a glass substrate surface cleaning apparatus and method that has a cleaning function that can be

appropriately applied to foreign matter (mainly glass cullet) of various sizes (for example, in the range from 10 μιη to 1000 μιη) that exists on glass substrates.

One aspect of the glass substrate surface cleaning apparatus according to the present invention is constituted by a glass substrate surface cleaning apparatus 100 having a glass substrate support and transport mechanism 20 that supports a glass substrate 50 and transports the glass substrate in a first direction (M in FIG. 3) and a glass substrate surface cleaning mechanism 10 that includes a cleaning belt 11 that removes foreign matter 300 that adheres to the surface of the glass substrate and that slides on the surface of the glass substrate in a second direction (N in FIG. 3) that intersects the first direction The cleaning belt 11 includes a plurality of 3 -dimensional structured abrasive protrusions 70 on a surface thereof and grooves 60 located between the coating films. The width 62 of the grooves 60 is wider than the external width dimension of the foreign matter 300 adhered to the surface of the glass substrate.

Here, "cleaning" means removal of foreign matter (mainly glass cullet) from the glass substrate. "External width dimension of the foreign matter" means the maximum external peripheral width of the foreign matter in the second direction (N in FIG. 3) in which the cleaning belt slides on the glass substrate. "Groove" means the gap formed between a 3-dimensional structured abrasive protrusion and another adjacent

3 -dimensional structured abrasive protrusion. "Groove width" means the interval between the top 72 of a 3-dimensional structured abrasive protrusion 70and the top 72 of another adjacent 3-dimensional structured abrasive protrusion 70. Glass cullet means the glass waste produced when glass products are crushed or fragmented, or the like.

Another aspect of the present invention is the cleaning belt 11 used in the above glass substrate surface cleaning apparatus 100.

In addition, another aspect of the present invention is constituted by a glass substrate surface cleaning method comprising transporting a glass substrate 50 in a first direction using a glass substrate support and transport mechanism20 and sliding a cleaning belt 11 of the glass substrate surface cleaning mechanism 10 in a second direction that intersects with the first direction on the surface of the glass substrate 50 in order to remove foreign matter 300 adhered to the surface of the glass substrate 50. The cleaning belt includes a plurality of 3-dimensional structured abrasive protrusions 70 on a surface thereof and grooves 60 located between the coating films. The width of the grooves 60 is wider than the external width dimension of the foreign matter 300 adhered to the surface of the glass substrate 50.

According to the glass substrate surface cleaning apparatus and method of the present invention, it is possible to appropriately and reliably remove foreign matter (mainly glass cullet) having a range of sizes from a glass substrate.

Brief Description of the Drawings

FIG. 1 is a perspective view illustrating the overall configuration of a glass substrate surface cleaning apparatus according to the present invention;

FIG. 2 is a front elevation view illustrating the overall configuration of the glass substrate surface cleaning apparatus according to the present invention;

FIG. 3 is a plan view illustrating the relationship between the direction of transport (first direction, M) of a glass substrate and the direction of sliding (second direction, N) of the cleaning belt in the glass substrate surface cleaning apparatus according to the present invention;

FIG. 4 is a plan view illustrating a part of the 3 -dimensional structured abrasive material layer having a plurality of 3 -dimensional structured abrasive protrusions provided on the surface of the cleaning belt provided in the glass substrate surface cleaning apparatus according to the present invention;

FIG. 5 is a transverse cross-sectional view along the section line X-X in FIG. 4;

FIGS. 6a-6d are schematic cross-sectional views illustrating the behavioral relationship between foreign matter (glass cullet) adhered to the surface of a glass substrate and the grooves provided in the 3 -dimensional structured abrasive material layer of the cleaning belt when a width of the grooves is wider than an external width dimension of the foreign matter; and

FIGS. 7a-7d are schematic cross-sectional views illustrating the behavioral relationship between foreign matter (glass cullet) adhered to the surface of a glass substrate and the grooves provided in the 3 -dimensional structured abrasive material layer of the cleaning belt when a width of the grooves is narrower than an external width dimension of the foreign matter.

Detailed Description

Next, the embodiments of the present invention are explained in detail with reference to the drawings, but it should be understood that the present invention is not limited to the following embodiments, and that modifications, improvements, and the like can be made to the design as appropriate without deviating from the scope of the present invention, based on the knowledge of a person with ordinary skill in the art to which the present invention pertains.

FIGS. 1 and 2 illustrate a cleaning apparatus according to the present invention that can be used, for example, to clean the surface of glass substrates that are used in liquid crystal panels prior to the process of applying the polarizing plate in, for example, the liquid crystal panel manufacturing process disclosed in Japanese Unexamined Patent Application No. 2005-81297. In FIG. 1, a glass substrate surface cleaning apparatus 100 includes a glass substrate support and transport mechanism 20 and a glass substrate surface cleaning mechanism 10. The glass substrate support and transport mechanism 20 includes an import roller shaft 21, an export roller shaft 22, and a guide 23 that support a glass substrate 50 from the underside and transports it in a first direction (M in FIG. 3). The glass substrate surface cleaning mechanism 10 includes a cleaning belt 11 having an endless trajectory provided generally in the center above the glass substrate support and transport mechanism 20, a drive guide pulley 12, and driven guide pulleys 13, 14, 15 that rotate the cleaning belt 11 while applying a predetermined tension to the cleaning belt 11. The drive guide pulley 12 is connected to a drive motor 18 that applies the drive power to the drive guide pulley 12. Also, the cleaning belt 11 is disposed in a direction (second direction, N in FIG. 3) intersecting the transport direction (first direction, M in FIG. 3) of the glass substrate 50.

As illustrated in FIG. 2, when sliding, the cleaning belt 11 is disposed in contact with a top surface of a glass substrate 50, and a loading device 30 is disposed directly above the cleaning belt 11 to apply a load to press the cleaning belt against the glass substrate 50. Any type of loading device can be used as the loading device 30 as necessary, such as an air-blown type, a water pressure type, and so on. The load can be adjusted within the range from about 0.01 kg/cm² to about 3 kg/cm².

FIG. 3 illustrates the relationship between the glass transport direction (the first direction, M in FIG. 3) and the sliding direction (the second direction, N in FIG. 3) in the glass substrate surface cleaning apparatus 100. As illustrated in FIG. 3, the sliding direction (the second direction, N in FIG. 3) of the cleaning belt 11 on the glass substrate 50 is provided in a direction that intersects the transport direction (the first direction, M in FIG. 3) of the glass substrate 50. The reasons for disposing the cleaning belt 11 intersecting in this way are to widen the sliding surface on the glass substrate 50, and to relieve the impact when the glass substrate 50 impinges on the cleaning belt. The intersection angle Θ (FIG. 3) is provided specifically in the range of about 70° to about 85°, or about 95° to about 110°.

The cleaning belt sliding speed is determined taking into consideration the glass substrate transport speed, the glass substrate productivity, and the degree of removal of foreign matter. Specifically, the cleaning belt sliding speed in the second direction (N in FIG. 3) of the glass substrate 50 can generally be adjusted to the range from about 10 m to about 500 m per minute, and the transport speed in the first direction (M in FIG. 3) of the glass substrate 50 can generally be adjusted to the range from about 0.1 m to about 10 m per minute. The value of the ratio sliding speed/transport speed is generally in the range from about 2 to about 100. Therefore, in the glass substrate surface cleaning apparatus 100, removal of foreign matter due to the sliding of the cleaning belt 11 is mainly in the second direction (N in FIG. 3). FIGS. 4 and 5 illustrate the cleaning belt 11 used in the glass substrate surface cleaning mechanism 10 according to an embodiment of the present invention. As illustrated in FIGS. 4 and 5, the cleaning belt 11 used in the present invention is constituted from a the 3-dimensional structured abrasive material layer 80 that includes a plurality of 3-dimensional structured abrasive protrusions70 on a front surface and grooves 60 provided between the plurality of 3-dimensional structured abrasive protrusions 70, and a backing layer 90 that supports the 3-dimensional structured abrasive material layer 80 from a rear side of the front surface thereof.

The 3 -dimensioned structured abrasive material layer 80 is constituted from the 3-dimensional structured abrasive protrusions70 and grooves 60 on the surface of the backing layer 90.

The geometric shape of the 3-dimensional structured abrasive protrusions 70 can be selected from a group that includes, but is not limited to: a cubic shape, a prismatic shape, a circular cylindrical shape, a circular conical shape, a pyramidal shape, a truncated pyramidal shape (frustum of a pyramid), a truncated circular conical shape (frustum of a cone), and so on. Of these, forms having the truncated pyramidal form or the truncated circular conical form with a flat top surface are preferable. If the form is the truncated pyramidal form or the truncated conical form, the top surface of the 3-dimensional structured abrasive protrusions 70 are in plane contact with the glass substrate, and removal of foreign matter adhered to the surface of the glass substrate 50 is promoted.

The truncated pyramidal or truncated circular conical 3-dimensional structured abrasive protrusions 70 are generally formed precisely shaped. Here, "precisely shaped" has the same meaning as disclosed in PCT International Patent Publication No.

WO 98/39142, in which a binder precursor that includes abrasive particles is formed on the backing layer 90 using a manufacturing tool, then the binder precursor is hardened, to form the 3-dimensional structure.

The area of the top 72 of each of the truncated pyramids that are precisely shaped in this way is between about 0.2 mm² and about 20 mm², particularly about 1 mm² and about 10 mm². The bottom 74 of the truncated pyramids has an area that is a maximum of about 60% greater than the top, particularly a maximum of about 40% greater than the top, and more particularly a maximum of about 20% greater than the top. Also, the height (H in FIG. 5) of the truncated pyramids or cones is from about 0.2 mm to about 5 mm, and more particularly about 0.3 mm to about 3 mm. The form of the 3-dimensional structured abrasive protrusions 70 is ultimately determined based on consideration of the form of the foreign matter to be removed, in other words the size of the foreign matter and the strength of adhesion to the substrate, and so on.

The plurality of 3 -dimensional structured abrasive protrusions 70 is regularly and orderly disposed on the top surface of the backing layer 90 at equal intervals generally in the second direction (N in FIG. 3) in lattice or staggered form, or the like. This arrangement is referred to as "structured" with the same meaning as used in International Patent Publication No. W098/39142, so in this specification the abrasive material layer and the abrasive protrusion are referred to as the 3 -dimensional structured abrasive material layer and the 3 -dimensional structured abrasive protrusion, respectively.

The constituent materials of the cleaning belt 11 are the backing layer 90 and the

3-dimensional structured abrasive material layer 80. The 3-dimensional structured abrasive material layer 80 is made from abrasive particles and binder.

It is necessary that the backing layer 90 has the strength and durability to extend the life of the cleaning belt, and uniformly obtain foreign matter (mainly glass cullet) 300 over the whole width of the cleaning belt 11. It is necessary that the cleaning belt 11 have strength, deformability, and flexibility so that the cleaning belt 11 can uniformly conform to or be in close contact with the glass substrate 50. Polymer films, papers, fabrics, metal films, vulcanized fibers, or laminates or processed products thereof are exemplary materials of the backing layer. Examples of polymer films include, but are not limited to: polyester film, copolyester film, polyimide film, polyamide film, and so on. Examples of papers include, but are not limited to: paper impregnated with resin, to increase the strength, or the like. Examples of fabrics include, but are not limited to: woven or knitted fabric using fiber selected from resin fiber, cotton fiber, glass fiber, and combinations of these fibers, or the like. Polymer films may have a base coat of a material such as ethylene acrylate copolymer in order to promote adhesion with the base material of the 3-dimensional structured abrasive protrusions.

The 3-dimensional structured abrasive material layer 80 includes a binder matrix and an abrasive material component that includes abrasive particles dispersed in the binder matrix as its constituent components.

Preferably, the dimensions of the abrasive particles are fine, so that deep scratches are not imparted to the glass surface. For example, the dimension of the abrasive particles is an average particle diameter between about 0.01 and about 10 μιη, particularly between about 0.01 and about 5 um, and more particularly between about 0.01 and about 3 um. Examples of abrasive particles that can be applied to the present invention include, but are not limited to: diamond, cubic boron nitride, cerium oxide, fused aluminum oxide, heat- treated aluminum oxide, sol-gel aluminum oxide, silicon carbide, chromium oxide, silica, zirconia, alumina zirconia, iron oxide, garnet, calcium carbonate, and mixtures thereof. Particularly suitable are diamond, cubic boron nitride, aluminum oxide, silicon carbide, cerium oxide, and silica, having a Mohs hardness of 6 or higher.

The abrasive material layer is formed by hardening or gelation of the binder.

Examples of suitable binders according to the present invention include, but are not limited to: phenol resin, resole phenol resin, aminoplast resin, urethane resin, epoxy resin, acrylate resin, polyester resin, vinyl resin, melamine resin, acrylatized isocyanurate resin, urea formaldehyde resin, isocyanurate resin, acrylatized urethane resin, acrylatized epoxy resin, and mixtures thereof. The binder may be a thermoplastic resin.

Phenol resin, resole phenol resin, epoxy resin, acrylate resin, and urethane resin are particularly suitable.

The binder may be radiation hardenable. A radiation hardenable binder is a binder that is at least partially hardened or at least partially polymerized by radiation energy. Depending on the binder used, heat, infrared light, electron beam, ultra violet light, or visible light may be used as the energy source.

Typically these binders are polymerized by a free radical mechanism. Preferably they are selected from a group that includes acrylatized urethane, acrylatized epoxy, aminoplast derivitatives having an α, β unsaturated carbonyl group, ethylenically unsaturated compounds, isocyanurate derivatives having at least one acrylate group, isocyanate having at least one acrylate group, and mixtures thereof.

If the binder is hardened with ultra violet radiation, a photoinitiator is necessary to start the free radical polymerization. Examples of suitable photoinitiators for this purpose include, but are not limited to: organic peroxides, azo compounds, quinone, benzophenone, nitroso compounds, acryl halides, hydrazone, mercapto compound, pyrylium compounds, triacryl imidazole, bis-imidazole, chloro alkyl triazine, benzoin ether, benzyl ketal, thioxanthone and acetophenone derivatives. Preferred photoinitiators include 2, 2-dimethoxy-l, 2-diphenyl-l-ethanone, and 2-methyl-l-(4-methyl thiophenyl)- 2-morpholino-propane-l-one.

If the binder is hardened with visible light radiation, a photoinitiator is necessary to start the free radical polymerization. Examples of suitable photoinhibitors for this purpose include, but are not limited to, those disclosed in US Patent No. 4,735,632, from column 3, line 25 to column 4, line 10; column 5, lines 1-7, and column 6, lines 1-35. The abrasive material component is formed from a slurry that includes a plurality of abrasive particles dispersed in binder in the unhardened or ungelated state. In hardening or gelating, the abrasive material component is fixed, in other words, fixed in a predetermined shape and a predetermined structure.

Regarding the mixing proportion of abrasive particles with respect to binder in the abrasive material component, generally the abrasive particles are about 50 to about 1000 parts by mass to about 100 parts by mass binder, and particularly the abrasive particles are in the range of about 100 to about 700 parts by mass to about 100 parts by mass of binder. The proportion varies depending on the type and size of abrasive particle and the type of binder used.

Materials other than abrasive particles and binder may be included in the abrasive component. For example, common additives include, but are not limited to: coupling agents, wetting agents, dyes, pigments, plasticizers, fillers, releasing agents, abrasion auxiliary agents, and mixtures thereof.

The abrasive component can include a coupling agent. By adding a coupling agent, the viscosity of the slurry used for forming the abrasive component can be reduced. Suitable examples of this kind of coupling agent for the present invention include, but are not limited to: organic silane, zircoaluminate, and titanate. The quantity of coupling agent is generally less than about 5 wt%, and particularly less than about 2 wt%.

A plurality of the grooves 60 of the 3 -dimensional structured abrasive material layer 80 of the cleaning belt 11 is formed between the 3-dimensional structured abrasive protrusions 70. The shape of the grooves 60 is the same as the outer periphery of the 3-dimensional structured abrasive protrusions 70 on the top surface of the backing layer 90. Therefore, the depth of the grooves 60 is substantially the same as the height of the truncated pyramids, from about 0.2 mm to about 5 mm, and particularly from about 0.3 mm to about 3 mm. Also, the width of the grooves is not less than about 0.3 mm, particularly not less than about 0.5 mm, and more particularly not less than about 1 mm.

The groove dimensions of the cleaning belt 11 of the glass substrate surface cleaning apparatus 100 according to the present invention are determined taking into consideration the dimensions of the foreign matter 300 to be removed (mainly glass cullet). FIGS. 6 and 7 schematically illustrate the relationship between the foreign matter 300 and the grooves 60 of the cleaning belt 11 during operation of the glass substrate surface cleaning apparatus 100. When the groove width is wider than the external width dimension of the foreign matter 300 adhered to the surface of glass substrate 50 as illustrated in FIG. 6, first the top of the foreign matter 300 on the glass substrate 50 just contacts the top 72 of the plurality of 3-dimensional structured abrasive protrusions 70 structured on the 3-dimensional structured abrasive material layer 80 (see FIG. 6A), but by sliding the cleaning belt 11 on the glass substrate 50, as a result of the flexibility of the cleaning belt 11 the foreign matter 300 is contained in the groove 60, and becomes enmeshed in the groove 60 (see FIG. 6B). Here, "foreign matter becomes enmeshed in the groove" means at least a part of the top of the foreign matter 300 is contained within a groove 60 formed between the 3-dimensional structured abrasive protrusions 70, and is subject to a shear force in the second direction (N in FIG. 3) by the 3-dimensional structured abrasive protrusions 70 due to the sliding of the cleaning belt 11.

Thereafter, the foreign matter 300 within the groove 60 impacts a side wall of the groove 60, in other words a side wall of the 3-dimensional abrasive material layer 80 that has good shape maintenance (see FIG. 6C), and finally the foreign matter 300 is wiped off the glass substrate 50 and removed by moving within the groove 60 (see FIG. 6D).

On the other hand, when the groove width 62 is narrower than the external width dimension of the foreign matter 300 adhered to the glass substrate surface as illustrated in FIG. 7, first, from the state in which the top of the foreign matter 300 on the glass substrate 50 contacts the top 72 of the plurality of 3-dimensional structured abrasive protrusions 70 on the 3-dimensional structured abrasive material layer 80, thereafter even when the foreign matter 300 arrives at a groove 60 due to the sliding of the cleaning belt 11 , the foreign matter 300 is not contained within the groove 60, but just slides across the top of the abrasive laminate (3-dimensional structured abrasive protrusions 70), and the foreign matter 300 remains on the glass substrate 50 without being wiped off the glass substrate 50.

The following is a specific example of a method of cleaning the glass substrate 50 surface. The glass substrate surface cleaning apparatus according to the present invention operates by the following procedure.

(1) First, sampling is carried out for a foreign matter generation status survey on a glass substrate from the same manufacturing lot as the glass substrate 50, and from the sampling, the number of particles of foreign matter and the external dimensions of the foreign matter are surveyed to obtain information on the foreign matter.

Here, a survey using an optical microscope, or a survey using an image processing device, or the like, can be carried out as the foreign matter generation status survey. (2) The maximum value of the external width dimension of the foreign matter 300 in the sliding direction of the cleaning belt (second direction) for the manufacturing lot is predicted and a cleaning belt 11 with a groove width not less than this value is selected and fitted to the cleaning apparatus.

(3) After the first glass substrate 50 is placed on the glass substrate support and transport mechanism 20, the intersecting condition of the sliding direction of the cleaning belt (second direction, N in FIG. 3) with respect to the transport direction (first direction, M in FIG. 3) is determined taking into consideration the operational efficiency of the glass substrate surface cleaning and so on.

(4) After bringing the cleaning belt 11 into close contact with one end of the glass substrate 50 in the longitudinal direction, the glass substrate 50 is transported in the transport direction (first direction, M in FIG. 3), and the cleaning belt 11 is slid in the sliding direction (second direction, N in FIG. 3).

(5) After completion of cleaning of the glass substrate surface of the first glass substrate 50, the second and subsequent glass substrates are placed on the glass substrate support and transport mechanism 20, and the processes in (3) and (4) below are repeated.

Next, an example of the present invention is explained together with a comparative example. Examples

Test Sample Preparation

Examples 1 and 2

A cleaning belt having the 3 -dimensional structured abrasive material layer adapted to be used in the glass substrate surface cleaning method according to the present invention was produced by the following method.

Abrasive material application liquid with the composition shown in Table 1 was applied with a knife coater onto a polypropylene forming film (2MM-30-500) to form a pattern of truncated square pyramids (frustum of a square pyramid) having a height of about 0.5 mm and a surface form with a length of the side of a square on the top of about 2 mm, with the distance between truncated square pyramids (frustum of a square pyramid) of about 1.6 mm, on top of which was laminated a 125 μιη polyester film, which was processed for easy bonding and that has a slip prevention coating that includes calcium carbonate particles and urethane resin on the rear surface thereof, the adhesive was hardened with ultra violet radiation, and the abrasive film and the forming film were separated. After heat treating the abrasive film for 24 hours at 110°C, it was cooled to room temperature, which completed the manufacture of the abrasive film. The process for easy bonding is prime coating with ethylene acrylate copolymer.

Table 1

Example 3, Comparative Example 1

Trizact wrapping film 5 mm 3 microns, aluminum oxide type 2, manufactured by Sumitomo 3M Limited.

This abrasive material has an abrasive material layer on the same film base material as Example 1 with a height of about 0.35 mm and a surface shape of a truncated square pyramid (frustum of a square pyramid) having a square top surface with a side of about 1.3 mm, and the length between the truncated square pyramids (frustum of square pyramid) is about 0.5 mm, and includes aluminum oxide abrasive particles with an average particle diameter of 3 μιη.

Evaluation Test Method and Evaluation Test Results

1) Glass substrates were prepared, the edges of two glass substrates were rubbed together over the glass substrates to generate glass cullet, which dropped onto the glass substrates, which were then left for a while for the glass cullet to adhere. The glass substrates were divided into a group with the dimension (external width dimension) of the glass cullet adhered to the glass substrate not more than 1.5 mm and not less than 0.5 mm, and a group with dimension of glass cullet less than 0.5 mm.

2) The abrasive film of Examples 1, 2, and 3, and Comparative Example 1 were processed into endless belts of width about 30 mm and length 2080 mm, to form the cleaning belts. The cleaning belts were fitted to a cleaning apparatus, the intersection angle Θ (FIG. 3) was set at 80°, the belt sliding speed was set at 100 m/minute, and the glass substrate was passed underneath the cleaning belt at a transport speed of 6 m/minute so that the surface on which the cullet was adhered contacted the abrasive material surface. At this time water was supplied to the rear surface of the belt at a pressure of about 0.1 MPa so that a load was applied to the belt and the abrasive material surface was pressed against the surface of the glass substrate, and water was also supplied to the surface of the glass substrate, so that the adhered cullet was cleaned from the surface. Table 2 shows the amount of cullet remaining on the glass surface after cleaning.

Table 2

Glass cullet removal performance score

1 Almost no glass cullet was removed.

2 Amount of residual glass cullet was reduced, but was insufficient.

3 Amount of residual glass cullet was greatly reduced, but from time to time reached problematic levels.

4 Amount of residual glass cullet was small.

5 Residual glass cullet was not detected.

Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

Claims

1. A glass substrate surface cleaning apparatus, comprising:

a glass substrate support that supports a glass substrate;

a transport mechanism that transports the glass substrate in a first direction; and a glass substrate cleaning mechanism that includes a cleaning belt that removes foreign matter adhered to a surface of the glass substrate and that slides on the surface of the glass substrate in a second direction that intersects the first direction;

wherein the cleaning belt includes a plurality of 3 -dimensional structured abrasive protrusions on a surface thereof and grooves located between the 3 -dimensional structured abrasive protrusions; and

wherein a width of the grooves is wider than an external width dimension of the foreign matter adhered to the surface of the glass substrate.

2. A cleaning belt used in a glass substrate surface cleaning apparatus for removing foreign matter adhered to a glass substrate, the cleaning belt comprising:

a plurality of 3 -dimensional structured abrasive protrusions on a surface thereof; and

grooves located between the 3-dimensional structured abrasive protrusions, wherein a width of the grooves is wider than an external width dimension of the foreign matter adhered to the glass substrate.

3. A glass substrate surface cleaning method, comprising the steps of:

transporting a glass substrate in a first direction using a glass substrate support and transport mechanism; and

sliding a cleaning belt in a second direction that intersects with the first direction on a surface of the glass substrate in order to remove foreign matter adhered to the surface of the glass substrate;

wherein the cleaning belt includes a plurality of 3-dimensional structured abrasive protrusions on a surface thereof and grooves located between the 3-dimensional structured abrasive protrusions; and