JP2020508226A - Method and apparatus for finishing glass sheets - Google Patents

Abstract

A method and apparatus for finishing an edge of a glass sheet is described. The edge of the glass sheet is finished using a grinding wheel mounted on one end of the spindle, the grinding wheel having a peripheral edge that contacts the edge of the glass sheet during grinding. The edge of the glass sheet is further finished by polishing the edge of the glass sheet with a polishing wheel attached to one end of a spindle, the polishing wheel having an end surface that contacts the glass edge during polishing.

Description

Cross-reference of related applications

  This application is incorporated by reference herein in its entirety, and incorporated herein by reference in its entirety. U.S. Provisional Patent Application Ser. No. 62 / 445,782, filed Jan. 13, 2017, 35 U.S.C. Claim the benefit of priority under Section 119 of the Patents Act.

  The present application relates to a method and apparatus for finishing edges of a glass sheet.

  Glass sheets are used in the backlighting of various products, for example, edge-lit liquid crystal display (LCD) devices, and in the manufacture of light guide plates (LGPs) that distribute light evenly across the display panel, the edge of the glass sheet is used. Is finished by grinding and polishing. Side-lit backlight units for such devices typically include LGPs made of a highly permeable plastic material such as polymethyl methacrylate (PMMA). The trend toward thinner displays is limited by the challenges associated with the use of polymer light guide plates (LGPs). Although such plastic materials exhibit excellent properties such as light transmission, these materials have relatively poor mechanical properties such as stiffness, coefficient of thermal expansion (CTE), and hygroscopicity. In particular, polymer LGPs lack the dimensional stability required for ultra-thin displays. When the polymer LGP is exposed to heat and humidity, the LGP swells and can impair photomechanical performance. Due to the instability of the polymer LGP, the designer needs to add a wider bezel and a thicker backlight with an air gap to compensate for this movement.

  Although glass sheets have been proposed as an alternative LGP solution for displays, the glass sheets must have the proper attributes to achieve sufficient optical performance with respect to transmission, scattering and light coupling. A glass sheet for a light guide plate must satisfy edge specifications such as squareness, straightness, and flatness. The glass sheet is cut to size to produce LGPs by mechanical scoring to form "vents", indentation lines that extend partially into the glass surface. The vent acts as a separation line for controlled crack propagation to make the glass sheet into two separate pieces by applying a mechanical force to the glass vent line. Dimensional tolerances are ± 0.5 mm and the average roughness of the edges is less than 0.2 micrometer. Displays with a thickness of 0.7 mm to 2.0 mm are currently up to 1.78 meters diagonal Of glass LGP are available. Corning Incorporated sells Corning Iris ™ glass for LGP, which exhibits a high transmission of almost 90% or more in the wavelength range of 400-650 nm.

  In an attempt to achieve the desired roughness of the edge, after scoring, the finish of the glass edge can be achieved by grinding and polishing the edge with a grinding wheel and a polishing wheel. Alternatively, etching with hydrofluoric acid and / or slurry polishing can be used. However, HF etching has safety and environmental considerations, and the etched edges may not provide the desired glass transmission. Slurry polishing takes longer to remove glass edge material than polishing with a polishing wheel, and it is more difficult to control the glass edge dimensions using slurry polishing. Traditional grinding and polishing using multiple wheels also takes time to replace the grinding and polishing wheels, and the polishing wheels can wear out quickly. Accordingly, it would be desirable to provide a method and apparatus for finishing the edges of glass sheets, especially those used for LGPs. It would also be desirable to provide devices and methods that provide additional functions in addition to grinding and polishing, such as forming holes in a glass sheet.

  A first aspect of the present disclosure relates to an apparatus for finishing an edge of a glass sheet by grinding and polishing the edge of the glass sheet. In one embodiment, such an apparatus is a worktable that supports a glass sheet while the edges are subjected to grinding and polishing, wherein the X axis is the direction of lateral movement of the glass sheet on the worktable in the plane. And the Y axis is the direction of vertical movement on a plane perpendicular to the X axis, and the Z axis is the direction of movement perpendicular to the plane. Worktable; rotation movable along the X and Y axes A rotary table having a rotary table rotary axis; a first spindle mounted on the rotary table and a second spindle having a common spindle rotary axis about which the first and second spindles rotate. A first spindle and a second spindle, wherein the common spindle rotation axis is orthogonal to the rotary table rotation axis; A grinding wheel attached to and a grinding wheel attached to a second spindle, wherein the grinding wheel is configured to grind an edge of the glass sheet with a common spindle rotation axis parallel to the Z axis. A grinding wheel and a grinding wheel, wherein the wheel is configured to grind the edge of the glass sheet with a common spindle rotation axis parallel to the X axis.

  A second aspect of the present disclosure relates to a method for finishing an edge of a glass sheet. In one embodiment, the method comprises supporting the glass sheet on a surface, wherein the X axis is the direction of lateral movement of the glass sheet on the surface and the Y axis is relative to the X axis. Grinding the edge of the glass sheet with a grinding wheel attached to one end of the first spindle, the direction of longitudinal movement on a vertical plane, the Z axis being the direction of movement perpendicular to the plane. Wherein the first spindle is oriented along the Z axis during grinding, and the grinding wheel includes a peripheral edge that contacts an edge of the glass sheet during grinding; and at one end of the second spindle Polishing the edge of the glass sheet at the end face of the mounted polishing wheel, wherein the second spindle is arranged parallel to the plane during polishing.

  The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects described below.

1 is a perspective view of an apparatus for finishing an edge of a glass sheet, showing a grinding wheel arranged to grind the edge of the glass sheet according to one or more embodiments. Detailed perspective view of a portion of the device shown in FIG. FIG. 2 is a perspective view of an apparatus for finishing an edge of a glass sheet, showing a polishing wheel arranged to polish the edge of the glass sheet according to one or more embodiments. 3 is a detailed perspective view of a portion of the apparatus shown in FIG. Detailed perspective view of a polishing wheel on a spindle according to one or more embodiments 1 is a detailed perspective view of a grinding wheel of the apparatus shown in FIG. 1 according to one or more embodiments. Side view showing a grinding wheel for grinding the edge of a glass sheet Side view showing a polishing wheel for polishing the edge of a glass sheet FIG. 4 is a side view illustrating a polishing wheel dressed by a dressing wheel according to one or more embodiments. FIG. 2 is a perspective view of a polishing wheel according to one or more embodiments. FIG. 2 is a perspective view of a polishing wheel according to one or more embodiments. FIG. 2 is a perspective view of a grinding wheel according to one or more embodiments. Perspective view of a drilling tool according to an embodiment FIG. 3 illustrates an exemplary embodiment of a light guide plate. FIG. 4 shows total reflection of light at two adjacent edges of glass LGP

  The various embodiments, examples of which are illustrated in the accompanying examples and figures, will now be described in detail.

  In the following description, like reference characters designate like or corresponding parts throughout the several views shown in the drawings. It is also understood that terms such as “top,” “bottom,” “outward,” “inward,” and the like are words of convenience and should not be construed as limiting, unless otherwise specified. In addition, whenever a group is described as comprising at least one of the group of elements and combinations thereof, the group individually or in combination with each other, represents any number of the listed elements. It is understood to include, consist essentially of, or consist of. Similarly, whenever a group is described as consisting of at least one of a group of elements or a combination thereof, the group may include, individually or in combination with each other, any number of the listed elements. It is understood that it can be comprised by. Unless otherwise specified, ranges of values, when recited, include both the upper and lower limits of the range, as well as ranges in between. As used herein, the indefinite articles "a", "an", and the corresponding definite article "the" mean "at least one" or "one or more", unless otherwise indicated. It is also understood that the various features disclosed in the specification and drawings can be used in any and all combinations.

  A method and apparatus for finishing an edge of a glass sheet is described herein. In certain embodiments, a glass sheet is finished by grinding and polishing to provide a light guide plate that can be used in a backlight unit according to embodiments of the present disclosure. Certain embodiments have similar or superior optical properties to light guide plates made of PMMA and have stiffness, coefficient of thermal expansion (CTE), and dimensional stability in high humidity conditions compared to PMMA light guide plates Provided is a light guide plate having much better mechanical properties such as properties.

  Referring now to FIGS. 1-6, an edge finishing apparatus 100 adapted to finish the edge 12 of the glass sheet 10 includes a work table that supports the glass sheet 10 while the edge 12 is subjected to grinding and polishing. 102. The apparatus can be used for grinding and / or polishing edge 12, and / or second edge 14, third edge 13, and fourth edge 15, according to one or more embodiments. In the illustrated embodiment, the worktable 102 is shown parallel to a horizontal plane, but the present disclosure is not limited to the worktable 102 in a horizontal plane. The phrase "horizontal plane" with respect to FIGS. 1-6 is the XY plane, where in FIGS. And the Y axis labeled Y is the direction of the vertical movement on the horizontal plane perpendicular to the X axis, and the Z axis labeled Z is the X axis shown in FIGS. , Y, and Z, the direction of movement perpendicular to the horizontal plane (XY plane). However, the XY plane can be a plane other than the horizontal plane, according to alternative embodiments.

  Referring to FIG. 5, the edge finishing apparatus 100 further includes a rotary table 104 movable along an X axis and a Y axis, and the rotary table 104 has a rotary table rotary shaft 105. The edge finishing apparatus 100 shown in FIGS. 1 to 6 comprises a first spindle 106 and a second spindle mounted on a turntable 104 having a common spindle rotation axis 107 on which a first spindle and a second spindle rotate. The common spindle rotation shaft 107 is orthogonal to the rotation table rotation shaft 105. The edge finishing device 100 further includes a grinding wheel 110 removably attached to the first spindle 106 and a polishing wheel 112 removably attached to the second spindle 108, wherein the grinding wheel 110 comprises: The grinding wheel 112 is configured to grind the edge 12 of the glass sheet 10 with the common spindle rotation axis 107 in a vertical direction (ie, parallel to the Z axis) and the grinding wheel 112 in a horizontal direction (ie, the X axis). Alternatively, the edge 12 of the glass sheet 10 is polished by the common spindle rotation shaft 107 (in the XY plane or the horizontal plane of the glass sheet 10 or in the horizontal plane).

  One or more embodiments of the edge finishing device 100 further include a plurality of first peripheral liquid cooling nozzles 120 arranged annularly, wherein the plurality of first peripheral liquid cooling nozzles 120 are adjacent to the grinding wheel 110. And is arranged to guide the coolant towards the peripheral grinding edge 111 of the grinding wheel 110. According to one or more embodiments, “adjacent” means that the first peripheral liquid-cooled nozzle 120 is about 1-10 cm, about 1-8 cm, about 1-6 cm, from the peripheral grinding edge 111 of the grinding wheel 110. Refers to being at a distance in the range of about 1-4 cm, or about 1-2 cm. The cooling liquid of the first peripheral liquid cooling nozzle 120 can flow to the first peripheral liquid cooling nozzle 120 through the first cooling liquid line 121. In one or more embodiments, the apparatus further includes a plurality of annular second peripheral liquid cooling nozzles 130, which are adjacent to the grinding wheel 110. The coolant of the second peripheral cooling nozzle can flow to the second peripheral liquid cooling nozzle 130 via the second coolant line 131. The coolant supplied to the first coolant line 121 and the second coolant line 131 can be supplied by a first supply line 127 (best shown in FIGS. 2 and 4), Can be connected to a tap source that supplies tap water or a coolant source (not shown) such as a pump connected to a tank (not shown) containing deionized and / or demineralized water. The annular arrangement of the first peripheral liquid cooling nozzle 120 and the second peripheral liquid cooling nozzle 130 provides for efficient cooling of the wheels and finished edges during grinding and polishing, edge burnout of the edges 12 of the glass sheet 10 and Reduce chipping.

  In one or more embodiments, the edge finishing device 100 further includes a plurality of remote liquid cooling nozzles 140 located remote from the grinding wheel 110 and the polishing wheel 112, wherein the remote liquid cooling nozzles 140 are ground and / or ground. During polishing, the coolant is directed toward the edge 12 of the glass sheet. In one or more embodiments, “separated” means that the remote liquid cooling nozzle 140 is about 10-200 cm, about 40-200 cm, from the edge and / or the grinding wheel 110 and the polishing wheel 112 of the glass sheet. It is meant to be at a distance in the range of about 80-200 cm, about 100-200 cm, or about 150-200 cm. 1-4, the remote liquid cooling nozzle 140 is shown as being located on a housing 150 that holds the turntable 104 in the gantry 152. The coolant can flow to the remote liquid cooling nozzle 140 via a third coolant line 141. The coolant supplied to the third coolant line 141 can be supplied by a second supply line 147 (best shown in FIGS. 2 and 4), which is a tap that supplies tap water Or a coolant source (not shown) such as a pump connected to a tank (not shown) containing deionized and / or deionized water.

  In one or more embodiments, the plurality of first peripheral liquid cooling nozzles and remote liquid cooling nozzles 140 are configured to operate during grinding of the glass sheet. The plurality of first peripheral liquid cooling nozzles 120 may include any suitable number of nozzles to provide sufficient cooling during grinding and / or polishing. For example, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 first peripheral liquid cooling nozzles 120 can be provided. Similarly, the plurality of second peripheral liquid cooling nozzles 130 may include any suitable number of nozzles to provide sufficient cooling during grinding and / or polishing. For example, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 second peripheral liquid cooling nozzles 130 can be provided. With respect to the remote liquid cooling nozzle 140, any number of nozzles can be provided and attached to the housing 150. As shown in FIGS. 1 to 6, remote liquid cooling nozzles 140 are provided on two side surfaces of housing 150. Each side of the housing may have, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 remote liquid cooling nozzles 140 to provide sufficient cooling during grinding and / or polishing. Etc., may have any suitable number of nozzles. The remote liquid cooling nozzle 140 can be spaced at any suitable distance from the edge 10 of the glass sheet during grinding and / or polishing. The remote liquid-cooled nozzle 140 may be positioned 5 cm, 10 cm, 15 cm, 20 cm, 25 cm, 30 cm, 35 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, 90 cm, 100 cm from the edge 12 of the glass sheet 10 during the grinding and / or polishing operation. , 125 cm, 150 cm, 200 cm, or a maximum of 500 cm. The first peripheral liquid cooling nozzle 120, the second peripheral liquid cooling nozzle 130, and the remote liquid cooling nozzle 140 can each be sized and shaped as needed to achieve the desired cooling effect. For example, the openings of the first peripheral liquid cooling nozzle 120, the second peripheral liquid cooling nozzle 130, and the remote liquid cooling nozzle 140 have diameters of 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0. It can be up to 6 mm, 0.8 mm, 0.9 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or 10 mm. The first coolant line 121, the second coolant line 131, the third coolant line 141, and the first supply line 127 and the second supply line 147 are respectively provided with conventional polyvinyl chloride (PVC). Alternatively, other plastic or metal tubes can be used. The coolant may include water, cold water, or other coolants.

  Referring now to FIGS. 7A and 9C and FIGS. 7B and 9A and 9B, in one or more embodiments, the grinding wheel 110 comprises a cylindrical wheel with a peripheral grinding edge 111 and a grinding wheel 112. Includes a cup-shaped wheel or cup wheel with a peripheral polishing edge 161 and a polishing end surface 162. As shown in FIGS. 7B, 9A and 9B, the cup wheel includes a cavitation region 164. The polishing wheel 112 shown in FIG. 9A includes a slot 166 located on the polishing end surface 162 to provide a slotted surface that contacts the edge 12 of the glass sheet during polishing. Suitable cup wheels include a slotted 2000 mesh (2000 #) epoxy resin cup wheel, a 5000 mesh epoxy resin wheel (5000 #), and a fine abrasive to reduce heat, with a Cu content of up to 50% by volume. Epoxy resin wheel 9000 mesh (9000 #).

  As shown in FIGS. 7A and 9C, the grinding wheel 110 includes a chamfer 125 that can be used to form a chamfer 19 on the edge 12 of the glass sheet 10. In one or more embodiments, the first spindle 106 and the grinding wheel 110 are such that the peripheral grinding edge 111 contacts the edge 12 of the glass sheet 10 during grinding and the second spindle 108 and the grinding wheel 112 Polished end surface 162 is configured to contact the edge of the glass sheet.

  Referring again to FIGS. 1-4, the turntable 104 is mounted on a gantry 152 that is movable along the Y axis, and the turntable 104 is movable along the X axis. The gantry 152 is movable on the Y-axis carriage 180 along the rail 18. The arrangement shown is exemplary, and linear movement of the gantry 152 along the Y axis is achieved using other methods, for example, using a worm gear assembly (not shown) including a screw shaft, a rotating nut, and a motor drive. It will be understood that it is possible. The turntable 104 is movable on the X-axis carriage 190 along the rail 192. The arrangement shown is exemplary, and linear translation of the rotary table 104 along the X axis can be achieved in other ways, such as a worm gear assembly including a screw shaft, a rotating nut, and a motor drive (not shown). Will be understood.

  Next, the operation of the edge finishing device 100 will be described. The edge finishing device 100 can be part of a computer numerical control (CNC) machine 200. Grinding wheel 110 with shank 195 is a chuck or collet (not shown) that can be driven by a motor (not shown) to rotate first spindle 106 and grinding wheel 110 about rotation axis 107. Can be attached to the first spindle 106. Similarly, polishing wheel 112 with shank 197 is driven by a chuck or collet (not shown) that can be driven by a motor (not shown) to rotate spindle and polishing wheel 112 about axis of rotation 107. It can be attached to the second spindle 108. The grinding wheel 110 can be rotated while translating along the edge 12 in the direction of the Y axis to remove material from the edge 12 of the glass sheet 10. CNC machine 200 includes a controller 210 that controls rotation and translation of grinding wheel 110 and polishing wheel 112. Controller 210 communicates with CNC machine 200 via either a wired or wireless connection. The controller 210 can be any suitable component that can control the translation and rotation of the components of the CNC machine 200 and the edge finishing device 100. For example, controller 210 can be a computer including a central processing unit, memory, appropriate circuitry and storage. CNC machine 200 further includes one or more position sensors 212, which may include, for example, a machine vision system including a camera such as a charge coupled device (CCD) camera to accurately track the position of the grinding wheel. It can be provided to accurately track where the edges of the glass sheet are ground and polished and provide information to the controller 210 to align the grinding and polishing wheels. A camera with a resolution of 0.001 micrometers can monitor single flat edges, rectangular parts, and circular parts.

  The positioning of the grinding wheel 110 and the polishing wheel 112 in the XY plane may be controlled by a roller or slide type rail system to effect movement of the grinding wheel 110 and the polishing wheel 112 in the X and Y directions. As described above, the parallel movement of the gantry 152 on the Y axis is performed via the Y axis carriage 180 on the rail 182, and the parallel movement on the X axis is performed via the X axis carriage 190 on the rail 192. The position sensor 212 communicates with the controller 210 to provide feedback to the controller about the positions of the grinding wheel 110 and the polishing wheel 112 and the glass sheet 10 during finishing of the glass sheet. The controller 210 of the CNC machine 200 can also be used to control the flow of coolant, which communicates with valves and pumps (not shown) to communicate with the first peripheral liquid cooling nozzle 120, The pressure, flow rate, and duration of the coolant flow through each of the two peripheral liquid cooling nozzles 130 and the remote liquid cooling nozzle 140 can be controlled.

  According to one or more embodiments, the rotating table 104 causes the grinding wheel 110 and the polishing wheel 112 to rotate about a rotation axis 105 that is orthogonal to the rotation axis 107 of the first spindle 106 and the second spindle 108. be able to. The turntable 104 rotates at regular intervals, ie, in any desired number of increments, for example, in 1, 5, 10, 15, 20, 45, 90, and 180 degree increments. Can rotate. A suitable turntable 104 is Detron Machine Co., Taiwan. , Ltd. Detron GX-170P available from the company. According to some embodiments, in use, during the grinding operation, the first spindle 106 is in a vertical direction parallel to the Z axis, or along the Z axis, as shown in FIG. First spindle 106 rotates about axis 107 and translates along the Y axis to remove material from edge 12. In one or more embodiments, the edges 13, 15 are translated from the edges 13, 15 by translating the first spindle along the X axis while rotating the first spindle 106 about the axis of rotation 107. Finishing can be achieved by removing material. Upon completion of the grinding operation, the controller 210 of the CNC machine 200 will determine that the second spindle 108 is positioned parallel to the XY plane or the horizontal plane of the worktable 102 and the glass sheet 10 so that the end face 162 is ground. A signal for rotating the first spindle 106 by 90 degrees about the rotation shaft 105 is transmitted so that the edge 12 of the glass sheet 10 can be brought into contact therewith. It will be appreciated that the orientation of the worktable 102 and the glass sheet may be other than horizontal, and in some embodiments, the worktable 102 and the glass sheet may be inclined at an angle to the horizontal. During the edge 12 polishing operation, the second spindle 108 rotates about the axis of rotation 107, causing the second spindle 108 to translate along the Y axis. The polishing operation can be performed on the edge 14 in the same manner.

  Thus, the rotary table 104 has a vertical (parallel to the Z axis) grinding on the first spindle 106 and a horizontal (second parallel to the horizontal or XY plane) second spindle 108. It will be appreciated that the polishing can be done with A grinding wheel 110 mounted on the first spindle 106 and a polishing wheel 112 mounted on the second spindle 108 allow for quick grinding and grinding operations on the edges 12, 14 of the glass sheet 10 without changing wheels. And it can proceed efficiently. The cooling provided by the first peripheral liquid cooling nozzle 120, the second peripheral liquid cooling nozzle 130 and the remote liquid cooling nozzle efficiently cools the edges of the glass sheet during finishing and the grinding wheel during the grinding and polishing process. And the grinding wheel is cooled as well.

  Typically, it is difficult to maintain a flat end surface 162 on the polishing wheel 112, especially after the polishing wheel 112 has polished many glass edges. The dressing process can make the wheel flatter and remove burnout areas, improving polishing efficiency. Referring now to FIG. 8, a conditioning tool 300 having a motor 302 and a dressing wheel 304 that rotates in the direction of arrow 305 is shown. Dressing wheel 304 contacts end surface 162 of polishing wheel 112 while polishing wheel 112 rotates about axis of rotation 107 and translates along direction 309. The conditioning tool 300 may be located off-line, i.e., remote from the edge finishing device 100 or separate therefrom. Alternatively, the conditioning tool 300 can be attached to or adjacent to the edge finishing device 100. While rotating the grinding wheel 112 at 3000 rpm, the grinding wheel 112 is translated at 800 mm / min at a depth of 0.01 mm of the glass edge, while the grinding wheel 112 is operated at 147 rpm with an outer diameter of 75 mm and an inner hole diameter. Dressing with a 12.7 mm and 25 mm thick GC (Green Silicon Carbide) 120 mesh (120 #) dressing wheel improved the flatness of the end face 162 after dressing from 14 micrometers to <1 micrometer.

  Next, referring to FIG. 10, a drilling tool 400 can also be coupled to the first spindle 106 or the second spindle 108 to form a hole in the glass sheet 10. Thus, in one or more embodiments, the method may include forming a hole in the glass sheet with a drilling tool coupled to the first spindle or the second spindle. The step of forming holes in the glass sheet can be performed before and after the grinding and polishing described herein.

  According to one or more embodiments, the edge finishing apparatus 100 can form an edge 12 that is perpendicular to the major surface of the glass sheet, without etching the edge with hydrofluoric acid, and / or Edges with improved edge roughness up to Ra <0.5 micrometers, Ra <0.4 micrometers, Ra <0.3 micrometers, or Ra <0.2 micrometers without slurry polishing the edges Can be provided. Stated another way, according to one or more embodiments by grinding and polishing using the edge finishing apparatus 100 of the present disclosure, Ra <0.5 micrometers, Ra <0.4 micrometers, Ra <. Glass sheets having an edge roughness of 0.3 micrometers or Ra <0.2 micrometers can be produced. The average roughness (Ra) of the edge of the glass sheet after grinding and polishing is available at www. keyence. It is measured according to ISO 4288: 1996 using a Keyence ultra-deep profilometer VK-8510 / VK-8500 model available from Keyence Corporation at Com. The edge finishing apparatus 100 can process glass sheets of various sizes, for example, glass sheets having XY dimensions ranging from 10 × 10 mm to 3600 mm × 1725 mm or more.

  Another aspect of the present disclosure relates to a method for grinding and polishing an edge of a glass sheet. In one embodiment, the method includes supporting the glass sheet on a surface, such as the worktable 102 shown in FIGS. 1-2, wherein the X axis is the lateral translation of the glass sheet on the surface. The Y axis is the direction of vertical movement on a plane perpendicular to the X axis, and the Z axis is the direction of movement perpendicular to the plane. In a particular embodiment, the X axis is the direction of the horizontal movement of the glass sheet on the horizontal surface, the Y axis is the direction of the vertical movement on the horizontal plane perpendicular to the X axis, and the Z axis Is the direction of vertical movement with respect to the horizontal plane. The method further includes grinding the edge of the glass sheet with a grinding wheel attached to one end of the first spindle, wherein the first spindle is oriented along the Z axis during grinding and the grinding wheel is rotated during grinding. Has a peripheral edge that contacts the edge of the glass sheet. The method further comprises polishing the edge of the glass sheet with a polishing wheel mounted on one end of a second spindle, wherein the second spindle is disposed parallel to a plane of the glass sheet during polishing, The polishing wheel has an end surface that contacts the edge during polishing. In certain embodiments where the worktable and glass sheet are horizontal, the second spindle is positioned horizontally (i.e., parallel to the XY plane) during polishing.

  In one or more embodiments, the method includes directing a cooling fluid to a peripheral edge of the grinding wheel using a first peripheral liquid cooling nozzle arranged annularly, wherein the first peripheral cooling nozzle comprises: Adjacent to the peripheral edge of the grinding wheel during grinding. In one or more embodiments, the method includes using the edge of the glass sheet during polishing and / or a plurality of remote liquid-cooled nozzles located away from the grinding wheel 110 and the polishing wheel 112 while polishing the glass sheet during polishing. Guiding the cooling fluid to the edge of In one or more embodiments, the method includes using the edge of the glass sheet during grinding and / or the plurality of remote liquid cooling nozzles located away from the grinding wheel 110 and the polishing wheel 112 to apply the edge to the edge during grinding. Directing a cooling fluid.

  In one or more embodiments, the method includes moving a first spindle and a second spindle relative to the glass sheet in a direction along the Y axis during grinding and polishing of the edge of the glass sheet. . In one or more embodiments of the method, the first spindle and the second spindle have a common spindle rotation axis 107 on which the first spindle and the second spindle rotate.

  In one or more embodiments of the method, the polishing wheel is a cup wheel. In one or more embodiments of the method, the polishing wheel is a cup wheel having a slot in an end face of the cup wheel. In one or more embodiments of the method, the finished glass sheet can be used as a light guide plate, the edge being the finished edge after grinding and polishing, the finished edge having an average of less than 0.2 micrometers. Has roughness.

  In one or more embodiments of the method, the finished edge is a light incident edge where the glass sheet after grinding and polishing of the edge scatters light within an angle of less than 12.8 degrees at full width at half maximum (FWHM) in transmission. It has perpendicularity so that it can be used as a light guide plate having In one or more embodiments of the method, the finished edge of the glass sheet has a light transmission of at least 95% at a wavelength of 450 nm. The glass sheet having this high transmittance is suitable for use as a light guide plate.

In one or more embodiments, the edge of the glass sheet is a first edge that is subjected to grinding and polishing to provide an edge that can be used as a first light incident edge in the manufacture of a light guide plate. . The method may further include grinding and polishing two edges adjacent to the first light incident edge. In one or more embodiments of the method, the glass sheet, 50 mol% _SiO 2 in the range of 80 mol%, 0 mol% 20 mol% in the range _Al 2 _{O 3,} and 0 mol% 25 mol percent range _{B 2} O ₃ as well as iron (Fe) concentrations in the range of less than 50 ppm by weight.

As mentioned above, the devices and methods described herein can be utilized in the manufacture of glass light guide plates. FIG. 11 illustrates an exemplary embodiment of a light guide plate that can be manufactured by the methods and apparatus of the present disclosure to finish a glass sheet by grinding and polishing edges. The glass sheet has the shape and structure of a typical light guide plate, including a glass sheet having a first surface 610 that can be a front surface and a second surface opposite the first surface that can be a back surface. Have. The first and second surfaces have a height H and a width W. In one or more embodiments, the first and / or second surfaces have an average roughness (R _a ) of less than 0.6 nm.

  The glass sheet 600 has a thickness T between the front and the back, which forms four edges. The thickness of the glass sheet is typically less than the front and back height and width. In various embodiments, the thickness of the light guide plate is less than 1.5% of the front and / or back height. In one or more embodiments, thickness T is about 2 mm, about 1.9 mm, about 1.8 mm, about 1.7 mm, about 1.6 mm, about 1.5 mm, about 1.4 mm, about 1.3 mm. About 1.2 mm, about 1.1 mm, about 1 mm, about 0.9 mm, about 0.8 mm, about 0.7 mm, about 0.6 mm, about 0.5 mm, about 0.4 mm, or about 0.3 mm. It is possible. The height, width, and thickness of the light guide plate are configured and dimensioned for use as LGPs in LCD backlight applications.

  In the embodiment shown, first edge 630 is a light incident edge that receives light provided by, for example, a light emitting diode (LED). In some embodiments, the light incident edge scatters light within an angle of less than 12.8 degrees at full width at half maximum (FWHM) in transmission. The light incident edge can be obtained by grinding and polishing the first edge 630 according to the apparatus and method described herein.

  The glass sheet further includes a second edge 640 adjacent the light incident edge 630 and a third edge 660 opposite the second edge 640 and adjacent the light incident edge 630, wherein the second edge 640 is Edge 640 and / or third edge 660 scatter light within an angle of less than 12.8 degrees FWHM in reflection. Second edge 640 and / or third edge 660 may include a reflection divergence angle of less than 6.4 degrees. The glass sheet includes a fourth edge 650 opposite the first edge 630.

  According to one or more embodiments, three of the four edges of the LGP have a mirror polished surface for two reasons: LED coupling and total internal reflection at two edges (TIR). . According to one or more embodiments, as shown in FIG. 12, light incident on a first edge 630 may include a second edge 640 adjacent the incident edge and a third edge 660 adjacent the incident edge. , Where the second edge 640 is opposed to the third edge 660. The second and third edges can also be processed without etching and / or slurry polishing the edges with hydrofluoric acid such that incident light undergoes total internal reflection from the two edges adjacent to the first edge. It may include a low edge average roughness of less than 5 micrometers, less than 0.4 micrometers, less than 0.3 micrometers, or less than 0.2 micrometers.

  Light may be incident into the first edge 630 from an array of LEDs 700 disposed along the first edge 630. The LED may be located at a distance less than 0.5 mm from the first edge 630. According to one or more embodiments, the LEDs may have a thickness or height that is less than or equal to the thickness of the glass sheet to provide efficient optical coupling to the light guide plate 600. According to one or more embodiments, the two edges 640, 660 may also include a divergence angle of reflection less than 6.4 degrees.

  The transmittance values were determined using several glass sheets having XYZ dimensions of 200 mm x 200 mm x 1.1 mm, using the edge finishing apparatus 100 described below and different grinding and polishing wheels. , Grinding and polishing. The transmittance after grinding and polishing is available at www. keyence. The measurements were made using a Keyence ultra-depth profilometer VK-8510 / VK-8500 model available from Keyence Corporation at Com. A laser light source (EQ-99X LDLS, Woburn, Mass., USA) at a wavelength ranging from 400 nm to 700 nm by directing the light source at the ground and polished edge and measuring the light transmitted through the opposite edge of the sample with a microscope. Transmittance was measured on a 200 mm x 200 mm x 1.1 mm glass sheet over the Y dimension (200 mm) using Energetiq Technology, Inc. (available from Inc.). Measurements were taken at wavelengths of 400 nm, 560 nm, and 630 nm. To provide the percent value compared to the cut edge sample, the transmittance measurements of the sample with the ground and polished edge were taken over the Y dimension (200 mm) after cutting and before grinding and polishing the edge. Compared to transmittance values measured through a glass sheet having YZ dimensions. The transmittance of a sample with a cutting edge was measured by directing a light source to the cutting edge and measuring the light transmitted through the opposite edge of the sample. After being cut, the sample measured before grinding and polishing the edge had a glass transmission of 100.00% at the cut edge. The transmittance values provided below are average values measured at wavelengths of 400 nm, 560 nm, and 630 nm.

  The average roughness was determined using several glass sheets having XYZ dimensions of 1219 mm x 150 mm x 1.1 mm, and the edge finisher 100 and different grinding and polishing wheels were used as described below. Used for grinding and polishing. The surface roughness of the edge after grinding and polishing is www. keyence. Measurements were made according to ISO 4288: 1996 using a Keyence ultra-deep profilometer VK-8510 / VK-8500 model available from Keyence Corporation at Com.

Example 1
The edges were ground using a 800 mesh (800 #) chamfered metal bonded diamond grinding wheel at a translation speed of 6000 mm / min to remove 0.10 mm edges. This is followed by a second edge polishing step on the end face of a 2000 mesh (2000 #) slotted epoxy resin cup wheel with a Cu content of up to 50% by volume, once at a translation speed of 6000 mm / min. To remove 0.03 mm. The third step involves polishing on the non-slotted end face of a 5000 mesh resin cup wheel (5000 #) with a Cu content of up to 50% by volume, with a single pass at a translation speed of 6000 mm / min. 0.005 mm was removed. The average roughness Ra measured using a Keyence microscope using the above technique was 0.04 micrometers. When the light transmittance was measured as described above, the light transmittance exceeded 99.5% and was measured as 99.8%.

Example 2
The edges of the glass sheet were ground using an 800 mesh (800 #) straight (non-chamfered) metal bonded diamond grinding wheel at a translation speed of 6000 mm / min to remove the 0.10 mm edge. This was followed by a second edge grinding step with a 800-mesh (800 #) chamfered metal bonded diamond grinding wheel to remove 0.05 mm by one pass at a translation speed of 6000 mm / min. The third step involves polishing on the end face of a slotless epoxy resin cup wheel 5000 # with a Cu content of up to 50% by volume, 0.005 mm by three passes at a translation speed of 6000 mm / min. Removed. The average roughness Ra measured using a Keyence microscope using the above technique was 0.035 micrometers.

  When the light transmittance was measured using the above method, it was measured to be more than 99.5% and 99.8%.

  Various modifications and variations can be made to the materials, methods, and articles described herein. Other aspects of the materials, methods, and articles described herein will be apparent from consideration of the specification and practice of the materials, methods, and articles disclosed herein. The specification and examples are intended to be considered as illustrative. It will be apparent to those skilled in the art that various modifications and changes can be made without departing from the spirit or scope of the present disclosure.

  Hereinafter, preferred embodiments of the present invention will be described separately.

Embodiment 1
In an apparatus for finishing the edge of a glass sheet,
A work table supporting the glass sheet while the edge is being subjected to grinding and polishing, wherein the X axis is the direction of lateral movement of the glass sheet on the work table on a plane, and the Y axis is A work table, the direction of vertical movement on the plane perpendicular to the X axis, and the movement direction of the Z axis perpendicular to the plane;
A rotary table movable along the X axis and the Y axis, the rotary table having a rotary table rotation axis;
A first spindle and a second spindle mounted on the turntable, the first spindle and the second spindle having a common spindle rotation axis about which the common spindle rotation axis is rotated. A first spindle and a second spindle, which are orthogonal to the rotary table rotation axis; and a grinding wheel attached to the first spindle and a polishing wheel attached to the second spindle, wherein the grinding wheel is Wherein the grinding wheel is configured to grind an edge of the glass sheet with the common spindle rotation axis parallel to the Z axis, and wherein the polishing wheel is mounted on the common spindle rotation axis parallel to the X axis. Grinding wheel and polishing wheel configured to polish the edge of the glass sheet Equipment.

Embodiment 2
A plurality of first peripheral liquid cooling nozzles arranged annularly, the first peripheral liquid cooling nozzle being adjacent to the first spindle and directing a cooling liquid toward a peripheral edge of the grinding wheel; The apparatus of embodiment 1, wherein the apparatus is arranged as follows.

Embodiment 3
Embodiment 3. The apparatus of embodiment 2, further comprising a plurality of second peripheral liquid cooling nozzles arranged annularly, wherein the second peripheral liquid cooling nozzle is adjacent to the second spindle.

Embodiment 4
3. The apparatus of embodiment 2, further comprising a plurality of remote liquid cooling nozzles positioned away from the grinding wheel and the polishing wheel and positioned to direct a cooling liquid toward an edge of the glass sheet.

Embodiment 5
The apparatus of embodiment 4, wherein the plurality of first peripheral liquid cooling nozzles and the remote liquid cooling nozzle are configured to operate during grinding of the glass sheet.

Embodiment 6
3. The apparatus of embodiment 2, wherein the plurality of first peripheral liquid cooling nozzles includes four cooling nozzles.

Embodiment 7
3. The apparatus of embodiment 2, wherein the plurality of first peripheral liquid cooling nozzles includes six cooling nozzles.

Embodiment 8
The apparatus of embodiment 1, wherein the grinding wheel comprises a cylindrical wheel with a peripheral grinding edge, and wherein the polishing wheel comprises a cup wheel with a peripheral polishing edge and a polishing end face.

Embodiment 9
The first spindle and the grinding wheel are configured to contact an edge of the glass sheet by the peripheral grinding edge during grinding, and wherein the second spindle and the grinding wheel The device of embodiment 8, wherein the device is configured to contact an edge of a glass sheet.

Embodiment 10
Embodiment 10. The apparatus of embodiment 9, wherein the polishing end surface of the cup wheel comprises a slotted surface.

Embodiment 11
The apparatus of embodiment 1, wherein the turntable is mounted on a gantry movable along the y-axis, and the turntable is movable along the x-axis.

Embodiment 12
Embodiment 12. The apparatus of embodiment 11, wherein the gantry is movable along a y-axis carriage and the turntable is movable along an x-axis carriage.

Embodiment 13
In a method of grinding and polishing the edge of a glass sheet,
A step of supporting a glass sheet on a surface, wherein the X axis is the direction of horizontal movement of the plane of the glass sheet on the surface, and the Y axis is the direction of vertical movement on the plane perpendicular to the X axis Wherein the Z axis is the direction of movement perpendicular to said plane;
Grinding the edge of the glass sheet with a grinding wheel attached to one end of a first spindle, wherein the first spindle is oriented along the Z axis during grinding, and the grinding wheel comprises: Polishing the edge of the glass sheet with an end face of a polishing wheel attached to one end of a second spindle, comprising: a peripheral edge that contacts the edge of the glass sheet during grinding; and A method wherein a second spindle is positioned parallel to said plane during polishing.

Embodiment 14
Directing a cooling fluid to the peripheral edge of the grinding wheel with a plurality of first peripheral liquid cooling nozzles arranged annularly, wherein the first peripheral liquid cooling nozzle is adjacent to the peripheral edge of the grinding wheel. 14. The method according to embodiment 13.

Embodiment 15
15. The method of embodiment 14, further comprising directing a cooling fluid to the edge of the glass sheet during polishing with a plurality of remote liquid cooling nozzles located away from the edge of the glass sheet.

Embodiment 16
16. The method of embodiment 15, further comprising directing a cooling fluid to the edge during grinding with the plurality of remote liquid cooling nozzles located away from the edge of the glass sheet.

Embodiment 17
Embodiment 15 further comprises the step of moving the first spindle and the second spindle relative to the glass sheet in a direction along the Y axis during grinding and polishing of the edge of the glass sheet. The described method.

Embodiment 18
Embodiment 18. The method of embodiment 17, wherein the first spindle and the second spindle rotate about a common spindle rotation axis.

Embodiment 19
Embodiment 16. The method of embodiment 15 wherein the polishing wheel is a cup wheel.

Embodiment 20
20. The method of embodiment 19, wherein the cup wheel includes a slot on an end face thereof.

Embodiment 21
14. The method of embodiment 13, further comprising forming a hole in the glass sheet with a drilling tool coupled to the first spindle or the second spindle.

Embodiment 22
14. The method of embodiment 13, wherein the edge is a finished edge after grinding and polishing having an average roughness of less than about 0.2 micrometers.

Embodiment 23
Said glass sheet, 50 mol% _SiO 2 in the range of ~80mol%, 0mol% ~20mol% range _Al 2 _{O 3,} and 0 mol% 25 mol% in the range of _B 2 _{O 3,} and less than 50 wt ppm Fe Embodiment 23. The method of embodiment 22 comprising:

Reference Signs List 10 Glass sheet 12 Edge 13 Third edge 14 Second edge 15 Fourth edge 19 Chamfer 100 Edge finishing device 102 Work table 104 Rotary table 105 Rotary table rotary shaft 106 First spindle 107 Common spindle rotary shaft 108 Second Spindle 110 grinding wheel 111 peripheral grinding edge 112 polishing wheel 120 first peripheral liquid cooling nozzle 121 first cooling liquid line 125 chamfer 127 first supply line 130 second peripheral liquid cooling nozzle 131 second cooling liquid line 140 Remote liquid cooling nozzle 141 Third cooling liquid line 147 Second supply line 150 Housing 152 Gantry 161 Peripheral polishing edge 162 Polishing end face 164 Hollow area 180 Y-axis carriage 182 Rail 190 X-axis carriage 92 rail 200 computer numerically controlled (CNC) machine 210 controller 212 the position sensor 300 the conditioning tool 302 Motor 304 dressing wheel 305 arrow 309 direction

Claims (12)

In an apparatus for finishing the edge of a glass sheet,
A work table supporting the glass sheet while the edge is being subjected to grinding and polishing, wherein the X axis is the direction of lateral movement of the glass sheet on the work table on a plane, and the Y axis is A work table, the direction of vertical movement on the plane perpendicular to the X axis, and the movement direction of the Z axis perpendicular to the plane;
A rotary table movable along the X axis and the Y axis, the rotary table having a rotary table rotation axis;
A first spindle and a second spindle mounted on the turntable, the first spindle and the second spindle having a common spindle rotation axis about which the common spindle rotation axis is rotated. A first spindle and a second spindle, which are orthogonal to the rotary table rotation axis; and a grinding wheel attached to the first spindle and a polishing wheel attached to the second spindle, wherein the grinding wheel is Wherein the grinding wheel is configured to grind an edge of the glass sheet with the common spindle rotation axis parallel to the Z axis, and wherein the polishing wheel is mounted on the common spindle rotation axis parallel to the X axis. Grinding wheel and polishing wheel configured to polish the edge of the glass sheet Equipment.   A plurality of first peripheral liquid cooling nozzles arranged annularly, the first peripheral liquid cooling nozzle being adjacent to the first spindle and directing a cooling liquid toward a peripheral edge of the grinding wheel; The apparatus of claim 1, wherein the apparatus is arranged as follows.   3. The apparatus of claim 2, further comprising a plurality of second peripheral liquid cooling nozzles arranged in an annular configuration, wherein the second peripheral liquid cooling nozzle is adjacent to the second spindle.   3. The apparatus of claim 2, further comprising a plurality of remote liquid cooling nozzles located remote from the grinding wheel and the polishing wheel and positioned to direct a cooling liquid toward an edge of the glass sheet.   The apparatus of claim 4, wherein the plurality of first peripheral liquid cooling nozzles and the remote liquid cooling nozzle are configured to operate during grinding of the glass sheet.   3. The apparatus of claim 2, wherein the plurality of first peripheral liquid cooling nozzles includes four cooling nozzles.   The apparatus of claim 2, wherein the plurality of first peripheral liquid cooling nozzles includes six cooling nozzles.   The apparatus of claim 1, wherein the grinding wheel comprises a cylindrical wheel with a peripheral grinding edge, and wherein the polishing wheel comprises a cup wheel with a peripheral polishing edge and a polishing end face.   The first spindle and the grinding wheel are configured to contact an edge of the glass sheet by the peripheral grinding edge during grinding, and wherein the second spindle and the grinding wheel are The apparatus of claim 8, wherein the apparatus is configured to contact an edge of a glass sheet.   The apparatus of claim 9, wherein the polished end face of the cup wheel comprises a slotted surface.   The apparatus of claim 1, wherein the turntable is mounted on a gantry movable along the y-axis, and wherein the turntable is movable along the x-axis.   The apparatus of claim 11, wherein the gantry is movable along a y-axis carriage and the turntable is movable along an x-axis carriage.

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