Patent Publication Number: US-2022212976-A1

Title: Methods and apparatus for manufacturing a ribbon

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority of U.S. Provisional Application Ser. No. 62/833,260 filed on Apr. 12, 2019 the contents of which are relied upon and incorporated herein by reference in their entirety as if fully set for the below. 
    
    
     FIELD 
     The present disclosure relates generally to methods and apparatus for manufacturing a ribbon and, more particularly, to methods and apparatus for heating a location of a nonuniformity of a molten portion of the ribbon. 
     BACKGROUND 
     It is known to control a thickness of a molten portion of a ribbon with a laser beam directed to a preselected portion of the molten portion of the ribbon. The laser beam can increase the temperature and reduce a viscosity of the preselected portion of the molten portion of the ribbon to cause the preselected portion to attain a desired thickness prior to cooling the molten portion to a glass portion of the ribbon. 
     SUMMARY 
     Some example embodiments of the disclosure are described below with the understanding that any of the embodiments may be used alone or in combination with one another. 
     Embodiment 1. A method of manufacturing a ribbon can comprise moving the ribbon along a travel direction of a travel path. The method can further comprise identifying a location of a nonuniformity in a characteristic of a molten portion of the ribbon. The method can further comprise deflecting a pulsed laser beam. The method can further comprise impinging the deflected pulsed laser beam on a heating zone comprising the location of the nonuniformity. The heating zone can be elongated in the travel direction of the travel path. 
     Embodiment 2. The method of embodiment 1, wherein the deflecting the pulsed laser beam can comprise reflecting the pulsed laser beam off a reflective surface of a polygonal reflecting device. 
     Embodiment 3. The method of embodiment 2, wherein the method can further comprise rotating the polygonal reflecting device at a substantially constant angular velocity about a rotation axis of the polygonal reflecting device. 
     Embodiment 4. The method of any one of embodiments 1-3, wherein the method can further comprise impinging the deflected pulsed laser beam on a sensing device to generate a signal, and calibrating a location of the deflected pulsed laser beam based on the signal from the sensing device. 
     Embodiment 5. A method of manufacturing a ribbon can comprise moving the ribbon along a travel direction of a travel path. The method can further comprise identifying a location of a nonuniformity in a characteristic of a molten portion of the ribbon on a treatment path of the molten portion of the ribbon. The method can further comprise reflecting a pulsed laser beam off a reflective surface of a polygonal reflecting device. The reflected pulsed laser beam can impinge on a heating zone on the treatment path. The method can further comprise rotating the polygonal reflecting device at a substantially constant angular velocity about a rotation axis of the polygonal reflecting device to move the heating zone along the treatment path. The heating zone can comprise the location of the nonuniformity. 
     Embodiment 6. The method of embodiment 5, wherein the method can further comprise impinging the reflected pulsed laser beam on a sensing device to generate a signal at a second angular orientation of the polygonal reflecting device, and calibrating a location of the reflected pulsed laser beam based on the signal from the sensing device. 
     Embodiment 7. A method of manufacturing a ribbon can comprise moving the ribbon along a travel direction of a travel path. The method can further comprise identifying a location of a nonuniformity in a characteristic of a molten portion of the ribbon. The method can further comprise deflecting a pulsed laser beam. The method can further comprise impinging the deflected pulsed laser beam on a heating zone of the location of the nonuniformity. The method can further comprise impinging the deflected pulsed laser beam on a sensing device. Impinging the deflected pulsed laser beam on the sensing device generates a signal. The method can further comprise calibrating a location of the deflected pulsed laser beam based on the generated signal. 
     Embodiment 8. The method of embodiment 7, wherein the deflecting the pulsed laser beam can comprise reflecting the pulsed laser beam off a reflective surface. 
     Embodiment 9. The method of any one of embodiments 1-8, wherein the characteristic can comprise a thickness of the ribbon. 
     Embodiment 10. The method of any one of embodiments 1-8, wherein the characteristic can comprise a temperature of the ribbon. 
     Embodiment 11. The method of any one of embodiments 1-10, wherein the pulsed laser beam can comprise a wavelength in a range from about 0.9 micrometers to about 12 micrometers. 
     Embodiment 12. The method of any one of embodiments 1-11, wherein the pulsed laser beam can be generated by a CO 2  laser generator. 
     Embodiment 13. The method of any one of embodiments 1-12, wherein the pulsed laser beam can impinge on the heating zone at a beam spot that may be repeatedly moved within the heating zone along the travel path. 
     Embodiment 14. The method of any one of embodiments 1-12, wherein the pulsed laser beam can comprise a plurality of pulsed laser beams impinging on the heating zone at corresponding beam spots arranged as an array of beam spots aligned in the travel direction of the travel path. 
     Embodiment 15. The method of embodiment 14, wherein the method can further comprise splitting the generated pulsed laser beam into the plurality of pulsed laser beams. 
     Embodiment 16. The method of any one of embodiments 1-12, wherein the heating zone can comprise an elliptical shape comprising a major axis extending in the travel direction of the travel path. 
     Embodiment 17. The method of embodiment 16, wherein the method can further comprise passing the pulsed laser beam through a cylindrical lens to generate the elliptical shape. 
     Embodiment 18. The method of embodiment 16, wherein the method can further comprise passing the pulsed laser beam through an anamorphic prism to generate the elliptical shape. 
     Embodiment 19. The method of any one of embodiments 1-18, wherein the method can further comprise controlling a characteristic of the pulsed laser beam to control a heating of the location of the nonuniformity. 
     Embodiment 20. The method of embodiment 19, wherein the characteristic of the pulsed laser beam can comprise a pulse frequency of the pulsed laser beam. 
     Embodiment 21. The method of any one of embodiments 19-20, wherein the characteristic of the pulsed laser beam can comprise a pulse width of the pulsed laser beam. 
     Embodiment 22. The method of any one of embodiments 19-21, wherein the characteristic of the pulsed laser beam can comprise a duty cycle of the pulsed laser beam. 
     Embodiment 23. The method of any one of embodiments 19-22, wherein heating the location of the nonuniformity can cause the nonuniformity to dissipate. 
     Embodiment 24. The method of any one of embodiments 1-23, wherein a width the heating zone across the travel path can be in a range from about 100 micrometers to about 30 millimeters. 
     Embodiment 25. The method of any one of embodiments 1-24, wherein the method can further comprise selectively controlling an elongated length of the heating zone extending in the travel direction. 
     Embodiment 26. The method of any one of embodiments 1-24, wherein the heating zone can comprise an elongated length extending in the travel direction in a range from about 1 millimeter to about 100 millimeters. 
     Embodiment 27. The method of embodiment 26, wherein the method can further comprise selectively controlling the elongated length of the heating zone. 
     Embodiment 28. The method of any one of embodiments 25-27, wherein a ratio of the elongated length of the heating zone to a width of the heating zone across the travel path can be about 3 or more. 
     Embodiment 29. The method of embodiment 28, wherein the width the heating zone can be in a range from about 100 micrometers to about 30 millimeters. 
     Additional embodiments disclosed herein will be set forth in the detailed description that follows. It is to be understood that both the foregoing general description and the following detailed description present embodiments intended to provide an overview or framework for understanding the nature and character of the embodiments disclosed herein. The accompanying drawings are included to provide further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the disclosure, and together with the description explain the principles and operations thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other embodiments are better understood when the following detailed description is read with reference to the accompanying drawings, in which: 
         FIG. 1  schematically illustrates an exemplary embodiment of a glass manufacturing apparatus configured to form a ribbon in accordance with embodiments of the disclosure; 
         FIG. 2  shows a perspective cross-sectional view of the glass manufacturing apparatus along line  2 - 2  of  FIG. 1  in accordance with embodiments of the disclosure; 
         FIG. 3  shows an enlarged view of one embodiment of a heating zone taken at view  3  of  FIG. 2 ; 
         FIG. 4  shows an enlarged view of another embodiment of a heating zone taken at view  3  of  FIG. 2 ; 
         FIG. 5  shows an enlarged view of another embodiment of a heating zone taken at view  3  of  FIG. 2 ; 
         FIG. 6  shows an enlarged view of another embodiment of a heating zone taken at view  3  of  FIG. 2 ; 
         FIG. 7  shows an enlarged view of another embodiment of a heating zone taken at view  3  of  FIG. 2 ; 
         FIG. 8  shows an enlarged view of another embodiment of a heating zone taken at view  3  of  FIG. 2 ; 
         FIG. 9  illustrates a schematic perspective view of embodiments of a treatment apparatus impinging a deflected pulsed laser beam on a heating zone of a molten portion of the ribbon; and 
         FIG. 10  illustrates a sensing device configured to generate a signal for use to calibrate a location of the deflected pulsed laser beam. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments will now be described more fully hereinafter with reference to the accompanying drawings in which example embodiments are shown. Whenever possible, the same reference numerals are used throughout the drawings to refer to the same or like parts. However, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. 
     The present disclosure relates to a glass manufacturing apparatus and methods for manufacturing a ribbon from a quantity of molten material. In some embodiments, the ribbon may comprise a molten portion that may be cooled to a glass portion. A slot draw apparatus, float bath apparatus, down-draw apparatus, up-draw apparatus, press-rolling apparatus or other glass manufacturing apparatus can be used to form the ribbon from a quantity of molten material. 
     Methods and apparatus for manufacturing glass will now be described by way of exemplary embodiments for forming a ribbon from a quantity of molten material. As schematically illustrated in  FIG. 1 , in some embodiments, an exemplary glass manufacturing apparatus  100  can comprise a glass melting and delivery apparatus  102 , a forming apparatus  101  including a forming vessel  140  designed to produce a molten portion  104  of a ribbon from a quantity of molten material  121 , and/or a treatment apparatus  142  designed to treat the molten portion  104  of the ribbon. For purposes of this application, the “molten portion” of the ribbon is considered the portion of the ribbon comprising a viscosity within a range of from about 10 4  to about 10 7.6  Poise. In some embodiments, the glass manufacturing apparatus  100  can be considered the treatment apparatus  142  without requiring features of the glass melting and delivery apparatus  102  or the forming apparatus  101 . In further embodiments, the glass manufacturing apparatus  100  can be considered the treatment apparatus  142  in combination with features of the forming apparatus  101  without requiring features of the glass melting and delivery apparatus  102 . In further embodiments, the glass manufacturing apparatus  100  may comprise the treatment apparatus  142  in combination features of the glass melting and delivery apparatus  102  and the forming apparatus  101 . 
     In some embodiments, the molten portion  104  of the ribbon may be cooled into a glass portion  103  of the ribbon comprising a central portion  152  disposed between a first outer edge  153  and a second outer edge  155  of the ribbon. Additionally, in some embodiments, a separated glass ribbon  106  can be separated from the glass portion  103  of the ribbon along a separation path  151  by a glass separator  149  (e.g., scribe, score wheel, diamond tip, laser, etc.). 
     In some embodiments, the glass melting and delivery apparatus  102  can include a melting vessel  105  oriented to receive batch material  107  from a storage bin  109 . The batch material  107  can be introduced by a batch delivery device  111  powered by a motor  113 . In some embodiments, an optional control device  115  (e.g., programmable logic controller) can be configured to (e.g., “programmed to”, “encoded to”, “designed to”, and/or “made to”) operated to activate the motor  113  to introduce a desired amount of batch material  107  into the melting vessel  105 , as indicated by arrow  117 . The melting vessel  105  can heat the batch material  107  to provide molten material  121 . In some embodiments, a melt probe  119  can be employed to measure a level of molten material  121  within a standpipe  123  and communicate the measured information to the control device  115  by way of a communication line  125 . 
     Additionally, in some embodiments, the glass melting and delivery apparatus  102  can include a first conditioning station including a fining vessel  127  located downstream from the melting vessel  105  and coupled to the melting vessel  105  by way of a first connecting conduit  129 . In some embodiments, molten material  121  can be gravity fed from the melting vessel  105  to the fining vessel  127  by way of the first connecting conduit  129 . For example, in some embodiments, gravity can drive the molten material  121  through an interior pathway of the first connecting conduit  129  from the melting vessel  105  to the fining vessel  127 . Additionally, in some embodiments, bubbles can be removed from the molten material  121  within the fining vessel  127  by various techniques. 
     In some embodiments, the glass melting and delivery apparatus  102  can further include a second conditioning station including a mixing chamber  131  that can be located downstream from the fining vessel  127 . The mixing chamber  131  can be employed to provide a homogenous composition of molten material  121 , thereby reducing or eliminating inhomogeneity that may otherwise exist within the molten material  121  exiting the fining vessel  127 . As shown, the fining vessel  127  can be coupled to the mixing chamber  131  by way of a second connecting conduit  135 . In some embodiments, molten material  121  can be gravity fed from the fining vessel  127  to the mixing chamber  131  by way of the second connecting conduit  135 . For example, in some embodiments, gravity can drive the molten material  121  through an interior pathway of the second connecting conduit  135  from the fining vessel  127  to the mixing chamber  131 . 
     Additionally, in some embodiments, the glass melting and delivery apparatus  102  can include a third conditioning station including a delivery vessel  133  that can be located downstream from the mixing chamber  131 . In some embodiments, the delivery vessel  133  can condition the molten material  121  to be fed into an inlet conduit  141 . For example, the delivery vessel  133  can function as an accumulator and/or flow controller to adjust and provide a consistent flow of molten material  121  to the inlet conduit  141 . As shown, the mixing chamber  131  can be coupled to the delivery vessel  133  by way of a third connecting conduit  137 . In some embodiments, molten material  121  can be gravity fed from the mixing chamber  131  to the delivery vessel  133  by way of the third connecting conduit  137 . For example, in some embodiments, gravity can drive the molten material  121  through an interior pathway of the third connecting conduit  137  from the mixing chamber  131  to the delivery vessel  133 . As further illustrated, in some embodiments, a delivery pipe  139  can be positioned to deliver molten material  121  to forming apparatus  101 , for example the inlet conduit  141  of the forming vessel  140 . 
     Forming apparatus  101  can comprise various embodiments of forming vessels in accordance with features of the disclosure including a forming vessel with a wedge for fusion drawing the ribbon, a forming vessel with a slot to slot draw the ribbon, or a forming vessel provided with press rolls to press roll the ribbon from the forming vessel. By way of illustration, the forming vessel  140  shown and disclosed below can be provided to fusion draw molten material  121  off a bottom edge, defined as a root  145 , of a forming wedge  209  to produce the molten portion  104  of the ribbon that can be drawn and cooled into the glass portion  103  of the ribbon. For example, in some embodiments, the molten material  121  can be delivered from the inlet conduit  141  to the forming vessel  140 . The molten material  121  can then be formed into the molten portion  104  of the ribbon based at least in part on the structure of the forming vessel  140 . For example, as shown, the molten material  121  can be drawn as the molten portion  104  off the root  145  of the forming vessel  140  and moved along a travel direction  154  of a travel path  150 . 
     In some embodiments, edge directors  163 ,  164  can direct the molten portion  104  off the forming vessel  140  and help define a width “W” of the resulting glass portion  103  of the ribbon. In some embodiments, the width “W” of the glass portion  103  can extend between the first outer edge  153  of the glass portion  103  and the second outer edge  155  of the glass portion  103 . In some embodiments, the width “W” of the glass portion  103  can be greater than or equal to about 20 mm, such as greater than or equal to about 50 mm, such as greater than or equal to about 100 mm, such as greater than or equal to about 500 mm, such as greater than or equal to about 1000 mm, such as greater than or equal to about 2000 mm, such as greater than or equal to about 3000 mm, such as greater than or equal to about 4000 mm, although other widths less than or greater than the widths mentioned above can be provided in further embodiments. For example, in some embodiments, the width “W” of the glass portion  103  can be from about 20 mm to about 4000 mm, such as from about 50 mm to about 4000 mm, such as from about 100 mm to about 4000 mm, such as from about 500 mm to about 4000 mm, such as from about 1000 mm to about 4000 mm, such as from about 2000 mm to about 4000 mm, such as from about 3000 mm to about 4000 mm, such as from about 20 mm to about 3000 mm, such as from about 50 mm to about 3000 mm, such as from about 100 mm to about 3000 mm, such as from about 500 mm to about 3000 mm, such as from about 1000 mm to about 3000 mm, such as from about 2000 mm to about 3000 mm, such as from about 2000 mm to about 2500 mm, and all ranges and subranges therebetween. 
       FIG. 2  shows a cross-sectional perspective view of the forming apparatus  101  (e.g., forming vessel  140 ) along line  2 - 2  of  FIG. 1 . In some embodiments, the forming vessel  140  can include a trough  201  oriented to receive the molten material  121  from the inlet conduit  141 . For illustrative purposes, cross-hatching of the molten material  121  is removed from  FIG. 2  for clarity. The forming vessel  140  can further include the forming wedge  209  including a pair of downwardly inclined converging surface portions  207 ,  208  extending between opposed ends  210 ,  211  (See  FIG. 1 ) of the forming wedge  209 . The pair of downwardly inclined converging surface portions  207 ,  208  of the forming wedge  209  can converge along the travel direction  154  to intersect along the root  145  of the forming vessel  140 . A draw plane  213  of the glass manufacturing apparatus  100  can extend through the root  145  along the travel direction  154  of the travel path  150 . In some embodiments, the molten portion  104  of the ribbon can move along the travel direction  154  of the travel path  150  and through the draw plane  213 . As shown, the draw plane  213  can bisect the forming wedge  209  through the root  145  although, in some embodiments, the draw plane  213  can extend at other orientations relative to the root  145 . 
     Additionally, in some embodiments, the molten material  121  can flow in a direction  156  into and along the trough  201  of the forming vessel  140 . The molten material  121  can then overflow from the trough  201  by simultaneously flowing over corresponding weirs  203 ,  204  and downward over the outer surfaces  205 ,  206  of the corresponding weirs  203 ,  204 . Respective streams of molten material  121  can then flow along the downwardly inclined converging surface portions  207 ,  208  of the forming wedge  209  to be drawn off the root  145  of the forming vessel  140 , where the flows converge and fuse into the molten portion  104  of the ribbon. The molten portion  104  of the ribbon can then be drawn off the root  145  in the draw plane  213  and the ribbon can move along the travel direction  154  of the travel path  150  and cooled into the glass portion  103  of the ribbon. 
     The molten portion  104  of the ribbon comprises a first major surface  215  and a second major surface  216  facing opposite directions and defining a thickness “T” (e.g., average thickness) of the molten portion  104 . In some embodiments, the thickness “T” of the molten portion  104  of the ribbon can be from about 0.5 millimeters (mm) to about 5 mm although other thicknesses can be provided in further embodiments. The thickness of the ribbon attenuates as it moves in the travel direction  154  of the travel path  150  and cools to transition from the molten portion  104  to the glass portion  103  of the ribbon. The final thickness of the glass portion  103  of the ribbon can be less than or equal to about 2 millimeters (mm), less than or equal to about 1 millimeter, less than or equal to about 0.5 millimeters, for example, less than or equal to about 300 micrometers (μm), less than or equal to about 200 micrometers, or less than or equal to about 100 micrometers, although other thicknesses may be provided in further embodiments. For example, in some embodiments, the thickness of the glass portion  103  can be from about 50 μm to about 750 μm, from about 100 μm to about 700 μm, from about 200 μm to about 600 μm, from about 300 μm to about 500 μm, from about 50 μm to about 500 μm, from about 50 μm to about 700 μm, from about 50 μm to about 600 μm, from about 50 μm to about 500 μm, from about 50 μm to about 400 μm, from about 50 μm to about 300 μm, from about 50 μm to about 200 μm, from about 50 μm to about 100 μm, including all ranges and subranges of thicknesses therebetween. In addition, the glass portion  103  of the ribbon can include a variety of compositions including, but not limited to, soda-lime glass, borosilicate glass, alumino-borosilicate glass, alkali-containing glass, or alkali-free glass. 
     The separated glass ribbon can then be processed into a desired application, e.g., a display application. For example, the separated glass ribbon can be used in a wide range of display applications, including liquid crystal displays (LCDs), electrophoretic displays (EPD), organic light emitting diode (OLED) displays, plasma display panels (PDPs), and other electronic displays. 
       FIGS. 3-4  illustrate features of example embodiments of the treatment apparatus  142  of the glass manufacturing apparatus  100  for treating the molten portion  104  of the ribbon. The treatment apparatus  142  can comprise a laser generator  301  designed to produce a pulsed laser beam  303 . In some embodiments, the laser generator can be designed to produce the pulsed laser beam  303  that can be absorbed by the molten portion  104  of the ribbon to heat the molten portion  104  of the ribbon at the location where the pulsed laser beam  303  impinges the surface of the molten portion  104  of the ribbon. In some embodiments, the laser generator  301  can comprise a CO 2  laser generator although other types of laser generators may be used in further embodiments. In addition or alternatively, in some embodiments, the pulsed laser beam  303  produced by the laser generator  301  can comprise a wavelength in a range from about 0.9 micrometers to about 12 micrometers. 
     The treatment apparatus  142  can further include a deflector device configured to deflect the pulsed laser beam  303  to impinge the deflected pulsed laser beam  303  on a heating zone of the molten portion  104  of the ribbon. As shown in  FIG. 2 , the deflected laser beam can impinge on a heating zone  217  on a treatment path  321  of the molten portion  104  while the heating zone  217  travels along direction  216   a . For example, the heating zone  217  can travel across substantially the entire width “W” in direction  216   a  from the first outer edge  153  to the second outer edge  155 . After reaching the second outer edge  155 , the heating zone may reappear at the first outer edge  153  and again travel in the direction  216   a  to the second outer edge  155 . Consequently, in some embodiments, the heating zone  217  can travel in the same direction  216   a  for each pass of the heating zone  217  across the width “W” of the ribbon from the first outer edge  153  to the second outer edge  155 . 
     As shown in  FIG. 2 , the deflected laser beam can impinge on the heating zone  217  on the treatment path  321  of the molten portion  104  while the heating zone  217  travels along direction  216   b . For example, the heating zone  217  can travel across substantially the entire width “W” in direction  216   b  from the second outer edge  155  to the first outer edge  153 . After reaching the first outer edge  153 , the heating zone may reappear at the second outer edge  156  and again travel in the direction  216   b  to the first outer edge  153 . Consequently, in some embodiments, the heating zone  217  can travel in the same direction  216   b  for each pass of the heating zone  217  across the width “W” of the ribbon from the second outer edge  155  to the first outer edge  153 . 
     As further shown in  FIG. 2 , the deflected laser beam can impinge on the heating zone  217  on the treatment path  321  of the molten portion  104  while the heating zone  217  travels along the direction  216   a  and the direction  216   b . For example, in some embodiments, the heating zone  217  can travel across substantially the entire width “W” in the direction  216   a  from the first outer edge  153  to the second outer edge  155 . After reaching the second outer edge  155 , the heating zone  217  can then travel across substantially the entire width “W” in the direction  216   b  from the second outer edge  155  to the first outer edge  153 . Consequently, in some embodiments, the heating zone  217  can travel in alternating directions  216   a  and  216   b  for each successive pass across the width “W” of the ribbon. 
     One or both of the directions  216   a  and  216   b  can extend across the travel direction  154  of the travel path  150 . For example, as shown, one or both of the directions  216   a  and  216   b  can extend perpendicular to the travel direction  154  along the direction of the width “W” although heating zone may travel along directions that are not perpendicular to the travel direction  154  in further embodiments. Various deflector devices can be used to cause the heating zone  217  to travel in one or both of the directions  216   a  and  216   b  as discussed above. For example, in some embodiments, the deflector device can comprise an acoustic optical deflector. In another example, in some embodiments, the deflector device can comprise an electro-optic deflector. In still another example, in some embodiments, the deflector device can comprise a rotating reflective surface. 
     In some embodiments, as shown in  FIG. 9 , the deflector device can comprise a polygonal reflecting device  305  including a plurality of reflective surfaces  307 . As shown, the polygonal reflecting device  305  may be rotated by a motor  309  to rotate in a rotation direction  311  about a rotation axis  313  of the polygonal reflecting device  305 . In some embodiments, the motor  309  may optionally be operated by a control device  315  (e.g., programmable logic controller) configured to (e.g., “programmed to”, “encoded to”, “designed to”, and/or “made to”) send command signals along communication line  317  to the motor  309  to rotate, in some embodiments, at a substantially constant angular velocity about the rotation axis  313  of the polygonal reflecting device  305 . Rotating the polygonal reflecting device  305  at a substantially constant angular velocity can help prevent damage to the motor  309  that may otherwise occur by frequently changing the angular velocity of the polygonal reflecting device  305 . In embodiments where the pulsed laser beam is reflected by the polygonal reflecting device  305 , the heating zone  217  may repeatedly travel in direction  216   a  or repeatedly travel in direction  216   b  depending on the rotation direction  311  that the polygonal reflecting device  305  rotates about the rotation axis  313 . 
     The control device  315  may be configured to (e.g., “programmed to”, “encoded to”, “designed to”, and/or “made to”) send command signals (e.g., by way of communication line  319 ) to the laser generator  301  to control a characteristic of the pulsed laser beam  303  to selectively control the heating of a location of a nonuniformity of the molten portion  104  of the ribbon. In some embodiments, the control device  315  may control a pulse frequency of the pulsed laser beam  303  to control the heating of the location of nonuniformity of the molten portion  104  of the ribbon. In some embodiments, the control device  315  may control a pulse width of the pulsed laser beam  303  to control the heating of the location of nonuniformity of the molten portion  104  of the ribbon. In some embodiments, the control device  315  may control a duty cycle of the pulsed laser beam  303  to control the heating of the location of nonuniformity of the molten portion  104  of the ribbon. In some embodiments, the control device  315  may control a plurality of characteristics of the pulsed laser beam  303  to control the heating of the location of nonuniformity of the molten portion  104  of the ribbon. For example, in some embodiments, the control device  315  may control the pulse frequency and the pulse width of the pulsed laser beam  303  to control the heating of the location of nonuniformity of the molten portion  104  of the ribbon. In some embodiments, the control device  315  may control the pulse frequency and the duty cycle of the pulsed laser beam  303  to control the heating of the location of nonuniformity of molten portion  104  of the ribbon. In some embodiments, the control device  315  may control the pulse width and the duty cycle of the pulsed laser beam  303  to control the heating of the location of nonuniformity of the molten portion  104  of the ribbon. In some embodiments, the control device  315  may control two or more of the pulse frequency, the pulse width and the duty cycle of the pulsed laser beam  303  to control the heating of the location of nonuniformity of molten portion  104  of the ribbon. 
     Further referring to  FIG. 9 , the treatment apparatus  142  can further comprise one or more sensing devices configured to monitor a characteristic of the ribbon. In some embodiments, the monitored characteristic of the ribbon can comprise a temperature and/or a thickness of the ribbon. In some embodiments, the one or more sensing devices can directly monitor a characteristic of the molten portion  104  of the ribbon. For example, with reference to  FIG. 2 , the characteristic of the molten portion  104  of the ribbon along a monitoring path  223   a  within the treatment path  321  may be directly monitored. In further embodiments, the characteristic of the molten portion  104  of the ribbon along a monitoring path  223   b  outside of the treatment path  321  (e.g., upstream or downstream from the treatment path  321 ) may be directly monitored. In some embodiments, a characteristic of the molten portion  104  of the ribbon within the treatment path  321  may be indirectly monitored. For example, as shown in  FIG. 9 , the characteristic of the glass portion  103  of the ribbon along a monitoring path  223   c  downstream from the molten portion  104  of the ribbon may be monitored. Then a corresponding characteristic of the molten portion  104  of the ribbon within the treatment path  321  may be determined based on the monitored characteristic along the monitoring path  223   c  of the glass portion  103 . For instance, a nonuniformity in the characteristic monitored along the monitoring path  223   c  of the glass portion  103  may indicate a corresponding nonuniformity in the characteristic of a portion of the treatment path  321  of the molten portion  104  of the ribbon located vertically above the monitored nonuniformity in the characteristic monitored along the monitoring path  223   c  of the glass portion  103 . 
     As shown in  FIG. 9 , the treatment apparatus  142  may optionally include a temperature sensor  323  configured to monitor the temperature of the molten portion  104  of the ribbon along a monitoring path (e.g., monitoring path  223   a ,  223   b ). In some embodiments, the temperature sensor  323  can comprise an infrared sensor (e.g., infrared camera) configured to monitor the temperature of the molten portion  104  by monitoring the infrared radiation being emitted by the molten portion  104  of the ribbon along one of the monitoring paths (e.g.,  223   a ,  223   b ). For instance, the temperature sensor  323  can comprise an infrared sensor (e.g., infrared camera) configured to directly monitor the temperature of the treatment path  321  of the molten portion  104  along the monitoring path  223   a . Sensed information relating to the temperature of the molten portion  104  of the ribbon along the monitoring path may then be transmitted by communication line  325  to a processor  327 . The processor  327  can then process the information to determine one or more locations of nonuniformity of the temperature of the molten portion  104  of the ribbon on the treatment path  321 . Based on the information from the processor  327 , the control device  315  may be configured to (e.g., “programmed to”, “encoded to”, “designed to”, and/or “made to”) modify the heating of the location of molten portion  104  of the ribbon to cause the nonuniformity to dissipate to provide a more uniform thickness of the molten portion  104  of the ribbon across the width “W” of the molten portion  104  of the ribbon. For example, a nonuniformity can be dissipated such that the thickness variation is less than 3 micrometers. Once the more uniform thickness is achieved, the molten portion  104  of the ribbon can proceed to be cooled into the glass portion  103  of the ribbon with a more uniform thickness of the glass portion  103  along the width “W” of the glass portion  103  of the ribbon. 
     In one embodiment, if the nonuniformity is determined to be a relatively low temperature compared to other locations of the monitoring path, the control device  315  may be configured to (e.g., “programmed to”, “encoded to”, “designed to”, and/or “made to”) send command signals by way of the communication line  319  to the laser generator  301  to increase the heating of the location(s) of the nonuniformity by increasing one or more of the pulse frequency, the pulse width, or duty cycle as discussed above while the pulsed laser beam  303  heats the location(s) of the nonuniformity. 
     In another embodiment, if the nonuniformity is determined to be a relatively high temperature compared to other locations of the monitoring path, the control device  315  may be configured to (e.g., “programmed to”, “encoded to”, “designed to”, and/or “made to”) send command signals by way of the communication line  319  to the laser generator  301  to decrease the heating of the location(s) of the nonuniformity by decreasing one or more of the pulse frequency, the pulse width or duty cycle as discussed above while the pulsed laser beam  303  heats the location(s) of the nonuniformity. 
     As further shown in  FIG. 9 , the treatment apparatus  142  may optionally include a thickness sensor  329  configured to sense information relating to a thickness of the ribbon. In some embodiments, the thickness sensor  329  may be provided without the temperature sensor  323 . In further embodiments, the temperature sensor  323  may be provided without the thickness sensor  329 . In further embodiments, the thickness sensor  329  and the temperature sensor  323  may both be provided to monitor one or more characteristics of the ribbon. If provided, the thickness sensor  329  can comprise an optical thickness sensor. The optical thickness sensor can comprise one or more sensors spanning across the width “W” of the ribbon. Alternatively, as shown, the optical thickness sensor  329  can be configured to scan in directions  333  across the travel direction  154  of the travel path  150 . For example, as shown, the thickness sensor  329  can be configured to scan in directions  333  perpendicular to the travel direction  154  although other scanning directions may be provided in further embodiments. In some embodiments, the optical thickness sensor  329  can include a laser that directs a laser beam to a location of a monitoring path (e.g., monitoring path  223   c  of the glass portion  103 ). A portion of the laser beam can reflect from the second major surface  216  to be sensed by the optical thickness sensor  329 . Another portion of the laser beam can pass through the thickness of the ribbon and then be reflected off the first major surface  215  back to be sensed by the optical thickness sensor  329 . The information regarding the reflected portions of the laser beam can be transmitted by way of communication line  335  to the processor  327 . The processor can then consider this information together with the refractive index of the ribbon to calculate the thickness of the ribbon along a monitoring path and/or calculate the thickness of the ribbon along the treatment path  321 . For example, as shown in  FIG. 9 , the thickness sensor  329  can sense the thickness of a glass portion  103  along monitoring path  223   c . The processor  327  can then process the information to determine a location of a nonuniformity in thickness sensed along the monitoring path  223   c . The sensed nonuniformity can be used by the processor to determine a corresponding location of a nonuniformity in a thickness of a corresponding portion of the molten portion  104  of the ribbon within the treatment path  321  that may be located vertically above the sensed nonuniformity in the glass portion  103 . Based on the information from the processor  327 , the control device  315  may be configured to (e.g., “programmed to”, “encoded to”, “designed to”, and/or “made to”) modify the heating of the location of the nonuniformity to cause the nonuniformity to dissipate to provide a more uniform thickness of the molten portion  104  across the width “W” of the molten portion  104  of the ribbon. Once the more uniform thickness is achieved, the molten portion  104  of the ribbon can proceed to be cooled into the glass portion  103  with a more uniform thickness of the glass portion  103  along the width “W” of the glass portion  103  of the ribbon. 
     In one embodiment, if the nonuniformity of thickness is determined to be a relatively high thickness compared to other locations of the treatment path  321 , the control device  315  may be configured to (e.g., “programmed to”, “encoded to”, “designed to”, and/or “made to”) send command signals by way of the communication line  319  to the laser generator  301  to increase the heating of the location(s) of the nonuniformity of thickness by increasing one or more of the pulse frequency, the pulse width or duty cycle as discussed above while the pulsed laser beam  303  heats the location(s) of the nonuniformity of thickness. The increased heating can reduce the viscosity of the molten material at the location(s) of the nonuniformity to reduce the thickness of the molten portion  104  of the ribbon at the location(s) of the nonuniformity of thickness. 
     In another embodiment, if the nonuniformity of thickness is determined to be a relatively low thickness compared to other locations of the treatment path  321 , the control device  315  may be configured to (e.g., “programmed to”, “encoded to”, “designed to”, and/or “made to”) send command signals by way of the communication line  319  to the laser generator  301  to decrease the heating of the location(s) of the nonuniformity of thickness by decreasing one or more of the pulse frequency, the pulse width or duty cycle as discussed above while the pulsed laser beam  303  heats the location(s) of the nonuniformity of thickness. The decreased heating can increase the viscosity of the molten material at the location(s) of the nonuniformity of thickness to increase the thickness of the molten portion  104  of the ribbon at the location(s) of the nonuniformity of thickness. 
     The deflected pulsed laser may impinge on the first major surface  215  of the molten portion  104  of the ribbon at one of various alternative heating zones  217  as schematically shown in  FIG. 2 .  FIG. 3  illustrates one embodiment where the heating zone  217  comprises a circular heating zone  217   a .  FIG. 4  illustrates another embodiment of the heating zone  217  comprising a square heating zone  217   b  with rounded corners. 
     In some embodiments, the heating zone can be elongated in the travel direction  154  of the travel path  150  wherein the heating zone includes a length  219  extending in the travel direction  154  that is greater than a width  221  of the heating zone that extends perpendicular to the travel direction  154 . Providing the length  219  extending in the travel direction  154  that is greater than the width  221  can increase the time that the location of the nonuniformity is heated as the molten portion  104  of the ribbon travels in the travel direction  154 ; thereby allowing more time for heat to conduct through the thickness “T” [e.g., from about 0.5 millimeters (mm) to about 5 mm] of the molten portion  104  of the ribbon that is traveling in the travel direction  154 . In some embodiments, a ratio of the length  219  of the heating zone to the width  221  of the heating zone can be about 3 or more. In some embodiments, in addition or alternatively to the above-referenced ratio of the length to width of 3 or more, the width  221  of the heating zone that extends perpendicular to the travel direction  154  can be in a range from about 100 micrometers to about 30 millimeters (mm). In some embodiments, in addition or alternatively to the above-referenced ratio of the length to width of 3 or more, the length  219  of the heating zone along the travel path  150  can be in a range from about 1 mm to about 100 mm. In some embodiments, the method can comprise selectively controlling the length  219  of the pulsed laser beam. For example, in some embodiments, the control device  315  may be configured to (e.g., “programmed to”, “encoded to”, “designed to”, and/or “made to”) selectively control the length  219  of the heating zone based on the speed that the molten portion  104  of the ribbon is traveling in the travel direction  154 . 
     In some embodiments, the heating zone can comprise an oblong shape such the length  219  extending in the travel direction  154  that is greater than the width extending perpendicular to the travel direction  154 .  FIG. 5  illustrates another embodiment of the heating zone  217  comprising an oblong shape in the form of a rectangular heating zone  217   c  with rounded corners. 
       FIG. 6  illustrates another embodiment of the heating zone  217  comprising a reciprocating beam spot  601  that produces an oblong heating zone  217   d . In some embodiments, the pulsed laser beam  303  can be moved to repeatedly move the beam spot  601  in the travel direction  154  of the travel path  150  to produce the oblong heating zone  217   d . In some embodiments, the pulsed laser beam  303  can be moved to repeatedly move the beam spot  218  in a direction  603  opposite travel direction  154  of the travel path  150  to produce the oblong heating zone  217   d . Alternatively, in some embodiments, the pulsed laser beam  303  can be moved to repeatedly reciprocate the beam spot  601  in the travel direction  154  and in the direction  603  opposite the travel direction  154  to produce the oblong heating zone  217   d . For example, the beam spot  601  can oscillate up in direction  603  and down in direction  154  to create the oblong heating zone  217   d . The oblong heating zone  217   d  provided by the moving beam spot  218  can include the length  219  extending in the travel direction  154  that is greater than the width  221  that extends perpendicular to the travel direction  154 . As shown schematically in  FIG. 9 , the treatment apparatus  142  may include a heating zone device  337  to modify the pulsed laser beam  303  produced by the laser generator  301  to create the heating zone including the length that is greater than the width. For instance, the heating zone device  337  can comprise an oscillator that causes the beam spot  601  to travel along one or more of directions  154  or  603 . In some embodiments, the oscillator can comprise a rotating mirror or other moving mirrors or moving optical components to cause the beam spot to quickly and repeatedly travel along the direction(s) to produce the oblong heating zone  217   d.    
     In some embodiments, as shown in  FIG. 7 , the heating zone  217  may comprise an oblong heating zone  217   e  provided by a plurality of pulsed laser beams impinging on the oblong heating zone  217   e  as an array of beam spots  701 . As shown, in some embodiments, the centers of the beam spots  701  can each be positioned on a linear axis that extends in the travel direction  154 . For instance, as shown in  FIG. 2 , the array of beam spots  701  comprises three beam spots with centers positioned on a linear axis that extends in the travel direction  154  to provide the oblong heating zone  217   e  with the length  219  extending in the travel direction  154  that is greater than the width  221  that extends perpendicular to the travel direction  154 . While three beam spots  701  are illustrated, in some embodiments two beam spots or more than three beam spots may be provided. Furthermore, the plurality of beam spots  701  may overlap one another although the beam spots may be slightly spaced apart in further embodiments. Overlapping the beam spots can create a more uniform heating along the length  219 . If providing the beam spots  701  in an overlapping aligned configuration, some embodiments may overlap the beam spots by 50% or less of the dimension of the beam spot  701  in the travel direction  154 . In some embodiments, the heating zone device  337  can comprise a beam splitter designed to split the pulsed laser beam  303  from the laser generator  301  into the plurality of pulsed laser beams that impinge on the major surface of the molten portion  104  of the ribbon in the above-described array of beam spots. 
     In some embodiments, as shown in  FIG. 8 , the heating zone  217  may comprise an oblong heating zone  217   f  provided as a beam spot  801  in the shape of an ellipse. As shown, the beam spot  801  of oblong heating zone  217   f  impinged by the pulsed laser beam  303  in the illustrated elliptical shape can comprise a major axis extending in the travel direction  154  of the travel path  150  such that the length  219  of the heating zone extends in the travel direction  154  of the travel path  150  and is greater than the width  221  that extends perpendicular to the travel direction  154 . Referring to  FIG. 9 , in some embodiments, an optical component  339  may be provided to shape the pulsed laser beam  303  and provide the oblong heating zone  217   f  in the shape of an ellipse. In some embodiments, the optical component  339  may comprise one or more cylindrical lenses. In some embodiments, the optical component  339  may comprise an anamorphic prism. 
     As shown in  FIGS. 9-10 , the treatment apparatus  142  can optionally comprise a sensing apparatus  341 .  FIG. 10  schematically shows embodiments of the sensing apparatus  341  comprising a sensing device  403 . In some embodiments, laser generator  301  can be configured to emit a pulsed laser beam  303  to be deflected with the deflector device (e.g., polygonal reflecting device) to impinge on the sensing device  403 . The pulsed laser beam  303  impinging on the sensing device  403  can generate a signal that may be communicated to the processor  327  by way of communication line  409 . The processor can then calibrate the location of the deflected pulsed laser beam  303  to allow more accurate and precise heating of the proper location of nonuniformity in the characteristic of the molten portion  104  of the ribbon. 
     Methods of manufacturing a ribbon will now be discussed with reference to  FIGS. 2-10 . Embodiments of methods of manufacturing the ribbon can comprise moving the ribbon along the travel direction  154  of the travel path  150 . For example, the ribbon may be fusion drawn from the root  145  of the forming vessel  140  to draw the ribbon along the travel direction  154  of the travel path  150 . Methods of the disclosure can further include identifying a location of a nonuniformity in a characteristic (e.g., temperature and/or thickness) of the ribbon such as the molten portion  104  of the ribbon. In some embodiments, methods may include monitoring the characteristic of the molten portion  104  of the ribbon along a monitoring path  223   a ,  223   b ,  223   c  to directly or indirectly identify the location of the nonuniformity in the characteristic (e.g., temperature, thickness) of the molten portion  104  of the ribbon. 
     In one embodiment, the method may include identifying the location of a nonuniformity in the temperature of the molten portion  104  of the ribbon. In some embodiments, the temperature may be monitored by the temperature sensor  323  (e.g., infrared camera). In some embodiments, the temperature sensor  323  may monitor the temperature of the molten portion  104  of the ribbon along a monitoring path  223   a ,  223   b  of the molten portion  104 . Signals relating to the sensed temperature can be communicated by way of the communication line  325  to the processor  327  that can determine one or more locations of a nonuniformity in the temperature along the monitoring path. 
     In another embodiment, the method may include identifying the location of the nonuniformity in the thickness of the ribbon (e.g., a thickness of the glass portion  103  and/or the molten portion  104  of the ribbon). In some embodiments, the thickness may be monitored by the thickness sensor  329  along the monitoring path  223   c  of the glass portion  103  of the ribbon. Signals relating to the sensed thickness can be communicated by way of the communication line  335  to the processor  327  that can determine one or more locations of a nonuniformity in the thickness of the glass portion  103  and/or the molten portion  104  located vertically above the glass portion  103 . 
     Methods of the disclosure can further comprise heating the molten portion  104  of the ribbon. In some embodiments, the pulsed laser beam  303  may be generated by the laser generator  301 . The laser generator  301  produces a pulsed laser beam that can impinge on a surface of the molten portion  104  of the ribbon to transfer energy from the pulsed laser beam  303  to the molten portion  104 . In some embodiments, a CO 2  laser generator may be used to produce the pulsed laser beam  303 , although other types of laser generators may be used in further embodiments. In some embodiments, the pulsed laser beam  303  may comprise a wavelength that can facilitate transfer of energy from the pulsed laser beam  303  to the molten portion  104  when the pulsed laser beam  303  impinges on the surface of the molten portion  104 . For instance, the pulsed laser beam can include a wavelength within a range of from about 0.9 micrometers to about 12 micrometers to allow the energy from the pulsed laser beam  303  to be absorbed by the molten portion  104  of the ribbon. The wavelength of the pulsed laser beam can be selected to optimize absorption on the particular type of molten material being treated. 
     The treatment apparatus  142  may then deflect the pulsed laser beam  303  to impinge on the treatment path  321  at the heating zone  217  on the treatment path  321  of the molten portion  104  of the ribbon. In some embodiments, as shown, the treatment path  321  can extend perpendicular to the travel direction  154  although the treatment path  321  may extend at other angles in further embodiments. Deflection of the pulsed laser beam  303  can be achieved using an acoustic optical deflector or an electro-optic deflector to deflect the generated pulsed laser beam  303 . In still further embodiments, the deflection of the pulsed laser beam  303  may comprise reflecting the pulsed laser beam  303  off a reflective surface. 
     Deflection of the pulsed laser beam  303  can result in movement of the heating zone  217  along one of the directions  216   a ,  216   b  of the treatment path  321 . In embodiments where the treatment path  321  is perpendicular to the travel direction  154 , the directions  216   a ,  216   b  can comprise directions of the width “W” of the ribbon. Movement of the heating zone  217  along the directions  216   a ,  216   b  can be achieved by the acoustic optical deflector, the electro-optic deflector or the reflective surface. For instance, the reflective surface can comprise a rotating reflective surface such as a rotating mirror. The rotating mirror can rotate about an axis wherein the heating zone  217  moves along one or both of the directions  216   a ,  216   b  depending on how the reflective surface is rotated. 
     In the illustrated embodiment, the reflective surface, if provided, can comprise a plurality of reflective surfaces  307  of the polygonal reflective device  305 . As shown, the plurality of reflective surfaces  307  can, in some embodiments, comprise a plurality of reflective flat mirrors that are radially arranged about the rotation axis  313  to define an outer polygonal peripheral shape of the polygonal reflective device  305 . Consequently, as shown in  FIG. 9 , the pulsed laser beam  303  reflecting off each reflective surface  307  of the polygonal reflective device  305  can result in a stroke of the heating zone  217  along direction  216   a  across the width “W” of the ribbon as the polygonal reflective device  305  rotates in rotation direction  311  about the rotation axis  313 . 
     In some embodiments, the method can comprise rotating the polygonal reflecting device at a substantially constant angular velocity in the rotation direction  311  about the rotation axis  313  of the polygonal reflecting device  305  to move the heating zone  217  along the treatment path  321 . Rotating the polygonal reflecting device  305  at a substantially constant angular velocity can increase the lifespan of the motor  309  driving the rotation of the polygonal reflecting device  305  by avoiding overheating and other stresses that can cause premature failure of the motor  309  due to constant changes in the angular velocity that may otherwise be required to provide a desired heating profile across the treatment path  321 . 
     Methods of the disclosure can comprise impinging the deflected (e.g., reflected) pulsed laser beam  303  on the heating zone  217  along the treatment path  321  wherein the heating zone  217  can comprise the identified location of the nonuniformity. For instance, as the heating zone  217  travels in the direction  216   a  and/or  216   b  of the treatment path  321 , the heating zone can be moved such that, during a period of time, the heating zone comprises the identified location of nonuniformity. A characteristic of the pulsed laser beam  303  can be controlled to selectively control the heating provided by the pulsed laser beam  303  depending on the location of the heating zone  217  along the treatment path  321 . For instance, controlling the characteristic of the pulsed laser beam  303  may comprise modifying one or more characteristics (e.g., pulse frequency, pulse width, and/or duty cycle) of the pulsed laser beam  303  for the period of time that the heating zone  217  comprises the identified location of nonuniformity. Modifying the one or more characteristics of the pulsed laser beam  303  can also allow selective adjustment of the heating of the molten portion  104  of the ribbon at the location of nonuniformity to treat the location of the nonuniformity different than other locations of the molten portion  104  along the treatment path  321 . In some embodiments, selective controlling of the heating of the nonuniformity can cause the nonuniformity to dissipate where the thickness variation at the location of nonuniformity relative to the thickness of other locations along the treatment path  321  is less than 3 micrometers. In some embodiments, the pulsed laser beam  303  may be turned off along a portion of the treatment path  321 . For example, the pulsed laser beam  303  may be turned of when the deflected pulsed laser beam  303  would not produce the heating zone  217  comprising the location of the nonuniformity. Rather, the pulsed laser beam  303  can be turned on only when the deflected pulsed laser beam  303  provides the heating zone  217  comprising the location of the nonuniformity. Turning off the pulsed laser beam  303  when the resulting beam spot would be located outside of the location of nonuniformity can avoid thinning portions of the ribbon outside of the location of the nonuniformity. Alternatively, the pulsed laser beam may be left on during a longer length of the treatment path  321  (e.g., across the entire width “W” of the ribbon) to change the amount of heating along the treatment path  321  wherein enhanced heating can be provided at the location of nonuniformity to cause relatively higher thinning at that location relative to locations outside of the nonuniformity to cause the nonuniformity to dissipate. 
     In one embodiment, if the nonuniformity comprises an overly thick location of the molten portion  104 , the method can include changing one or more characteristics of the pulsed laser beam  303  to increase the heating with the pulsed laser beam  303  while the heating zone  217  comprises the identified location of nonuniformity. The increased heating can dissipate the nonuniformity of thickness of the molten portion along the treatment path  321 . 
     In another embodiment, if the nonuniformity comprises a reduced temperature at the location of the molten portion  104 , the method can include changing one or more characteristics of the pulsed laser beam  303  to increase the heating with the pulsed laser beam  303  while the heating zone  217  comprises the identified location of nonuniformity. The increased heating can cause the temperature nonuniformity to dissipate where the temperature becomes more uniform across the treatment path  321  and across the width “W” of the ribbon. 
     In another embodiment, if the nonuniformity comprises an elevated temperature at the location of the molten portion  104 , the method can include changing one or more characteristics of the pulsed laser beam  303  to decrease the heating with the pulsed laser beam  303  while the heating zone  217  comprises the identified location of nonuniformity. The decreased heating can cause the temperature nonuniformity to dissipate where the temperature becomes more uniform across the treatment path  321  and across the width “W” of the ribbon. 
     In some embodiments, the polygonal reflecting device  305  may rotate at a substantially constant angular velocity while the characteristic of the pulsed laser beam  303  may be controlled to modify the heating profile across of the treatment path  321 . In such a manner, rotation of the polygonal reflecting device  305  at the substantially constant angular velocity can avoid failure of the motor  309  while changing the characteristic of the pulsed laser beam  303  can provide a desired heating profile across the treatment path  321  as the polygonal reflecting device  305  rotates. 
     In some embodiments, the method can comprise impinging the pulsed laser beam  303  on a heating zone  217  that, as illustrated in  FIG. 2 , may be elongated in the travel direction  154  of the travel path  150  wherein the length  219  of the heating zone  217  extending in the travel direction  154  is greater than the width  221  of the heating zone  217  extending perpendicular to the travel direction  154 . The heating zone may not be elongated in some embodiments, for example, with certain glass compositions or when the molten portion of the ribbon may be more responsive to heating through the entire thickness when the major surface of the ribbon is impinged by the pulsed laser beam. In some embodiments, providing the heating zone  217  that is elongated in the travel direction  154  can help increase the accumulated time that the location of the nonuniformity of the molten portion  104  of the ribbon is exposed to the pulsed laser beam  303  as the ribbon travels in the travel direction  154 . The increase in accumulated time of exposure can help the pulsed laser beam  303  more fully heat the full thickness of the molten portion  104  of the ribbon at the location of the nonuniformity even though the ribbon is traveling in the travel direction  154 . In some embodiments, a ratio of the elongated length  219  of the heating zone  217  to the width  221  of the heating zone  217  may be about 3 or more. In some embodiments, the width  221  the heating zone  217  can be in a range from about 100 micrometers to about 30 millimeters. In some embodiments, the length  219  of the heating zone  217  can be in a range from about 1 millimeter to about 100 millimeters. In some embodiments, the elongated length  219  of the heating zone  217  may be about a distance that the ribbon moves in a selected period of time in the travel direction  154 . In some embodiments, the period of time may be at least about 1 second although less than 1 second may be provided in further embodiments. For instance, the control device  315  may be configured to (e.g., “programmed to”, “encoded to”, “designed to”, and/or “made to”) send command signals to the heating zone device  337  to adjust the length  219  of the heating zone  217  based on the speed that the ribbon is traveling. For example, the control device  315  may be configured to (e.g., “programmed to”, “encoded to”, “designed to”, and/or “made to”) send command signals to the heating zone device  337  to cause the length  219  to adjust to be the distance the ribbon travels over a programmed period of time. 
     Various methods can be used to provide the optionally elongated heating zone as illustrated by the alternative heating zones  217  shown in  FIGS. 3-8 . In some embodiments, as discussed with respect to  FIGS. 5-8 , the heating zone  217  may optionally comprise an oblong heating zone including a length  219  in the travel direction  154  that is greater than the width  221  perpendicular to the travel direction  154 . For example,  FIG. 5  illustrates the heating zone  217  comprising an oblong shape in the form of the rectangular heating zone  217   c  with rounded corners. In another example, as shown in  FIG. 6  and described previously, the heating zone  217  comprising the reciprocating beam spot  601  that produces the oblong heating zone  217   d . In another embodiment, as shown in  FIG. 7  and described previously, the heating zone  217  may comprise the oblong heating zone  217   e  provided by a plurality of pulsed laser beams impinging on the oblong heating zone  217   e  as an array of beam spots  701 . In still another embodiment, as shown in  FIG. 8  and described previously, the heating zone  217  may comprise the oblong heating zone  217   f  provided as the beam spot  801  in the shape of an ellipse. 
     In some embodiments, methods can include calibrating the location of the deflected laser beam to more accurately control the heating of the location of the nonuniformity. By frequently calibrating the location of the deflected laser beam, the processor  327  can more accurately control the characteristic of the pulsed laser beam at the appropriate time to provide the desired heating of the heating zone  217  comprising the identified location of the nonuniformity in the molten portion  104  of the ribbon. To facilitate calibration, in some embodiments, the treatment apparatus  142  can comprise a sensing apparatus  341  schematically illustrated in  FIG. 9 . Features of one embodiment of the sensing apparatus  341  is shown in  FIG. 10 . As shown, the sensing apparatus  341  can optionally comprise a focusing lens  401  designed to focus the pulsed laser beam  303 . In further embodiments, the sensing apparatus  341  can comprise a mask  405  with an aperture  407 . As shown, as the pulsed laser beam approaches the aperture  407  in the mask  405 , the mask  405  blocks the pulsed laser beam  303  from passing through the mask  405  to reach the sensing device  403 . However, eventually, the pulsed laser beam  303  moves to a position that is aligned with the aperture  407  of the mask, wherein the pulsed laser beam  303  can pass through the aperture  407  to impinge on the sensing device  403 . The aperture  407  in the mask  405  can be reduced in size to increase the accuracy of locating the position of the pulsed laser beam at a particular time. Impinging the sensing device  403  with the pulsed laser beam  303  generates a signal that passes along communication line  409  to the processor  327  that then calibrates the precise location of the deflected pulsed laser beam based on the signal from the sensing device. 
     In some embodiments with a rotating polygonal reflecting device  305 , the method can include reflecting the pulsed laser beam  303  off a reflective surface  307  of the polygonal reflecting device  305  to impinge on the molten portion  104  of the ribbon at a first angular orientation of the polygonal reflecting device and further reflect the pulsed laser beam  303  off the reflective surface  307  of the polygonal reflecting device  305  to impinge on the sensing device  403  at a second angular orientation different than the first angular orientation to calibrate the location of the reflected pulsed laser beam  303 , for example, at least once for each stroke of the heating zone traveling across the width “W” of the ribbon. For example, as shown in  FIG. 9 , the reflected pulsed laser beam may move such that the heating zone travels along direction  216   a  along the treatment path  321  across the width “W” until the heating zone reaches the first outer edge  153  of the ribbon. Further rotation of the polygonal reflecting device  305  in rotation direction  311  causes the laser beam to travel off the first outer edge  153  and laterally outside the first outer edge  153  to eventually impinge on the sensing device  403  laterally outside the first outer edge  153 . As such, the calibration of the location of the pulsed laser beam  303  can be conducted without interfering with the heating of the molten portion  104  of the ribbon along the treatment path  321  since unused portions of the pulsed laser beam that has travelled outside the first outer edge  153  may be used to calibrate the location of the pulsed laser beam  303 . Although not shown, another sensing apparatus (similar or identical to the sensing apparatus  341 ) may be provided laterally outside the second outer edge  155 . In such embodiments, calibration of the pulsed laser beam  303  may be conducted twice for each stroke of the heating zone traveling across the width “W” of the ribbon to further increase precision of calibration of the location of the pulsed laser beam  303 . 
     Embodiments and the functional operations described herein can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Embodiments described herein can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a tangible program carrier for execution by, or to control the operation of, data processing apparatus. The tangible program carrier can be a computer-readable medium. The computer-readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, or a combination of one or more of them. 
     The term “processor”, “controller” or “control device” can encompass all apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, or multiple processors or computers. The processor can include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. 
     A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, or declarative or procedural languages, and it can be deployed in any form, including as a standalone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network. 
     The processes described herein can be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit) to name a few. 
     Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read only memory or a random-access memory or both. The essential elements of a computer are a processor for performing instructions and one or more data memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto optical disks, or optical disks. However, a computer need not have such devices. Moreover, a computer can be embedded in another device, e.g., a mobile telephone, a personal digital assistant (PDA), to name just a few. 
     Computer-readable media suitable for storing computer program instructions and data include all forms of data memory including nonvolatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry. 
     To provide for interaction with a user, embodiments described herein can be implemented on a computer having a display device, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, and the like for displaying information to the user and a keyboard and a pointing device, e.g., a mouse or a trackball, or a touch screen by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, input from the user can be received in any form, including acoustic, speech, or tactile input. 
     Embodiments described herein can be implemented in a computing system that includes a back-end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front-end component, e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with implementations of the subject matter described herein, or any combination of one or more such back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication, e.g., a communication network. Embodiments of communication networks include a local area network (“LAN”) and a wide area network (“WAN”), e.g., the Internet. 
     The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises from computer programs running on the respective computers and having a client-server relationship to each other. 
     It will be appreciated that the various disclosed embodiments may involve particular features, elements or steps that are described in connection with that particular embodiment. It will also be appreciated that a particular feature, element or step, although described in relation to one particular embodiment, may be interchanged or combined with alternate embodiments in various non-illustrated combinations or permutations. 
     It is also to be understood that, as used herein the terms “the,” “a,” or “an,” mean “at least one,” and should not be limited to “only one” unless explicitly indicated to the contrary. Likewise, a “plurality” is intended to denote “more than one.” 
     Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, embodiments include from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. 
     The terms “substantial,” “substantially,” and variations thereof as used herein are intended to note that a described feature is equal or approximately equal to a value or description. 
     Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that any particular order be inferred. 
     While various features, elements or steps of particular embodiments may be disclosed using the transitional phrase “comprising,” it is to be understood that alternative embodiments, including those that may be described using the transitional phrases “consisting” or “consisting essentially of,” are implied. Thus, for example, implied alternative embodiments to an apparatus that comprises A+B+C include embodiments where an apparatus consists of A+B+C and embodiments where an apparatus consists essentially of A+B+C. 
     It should be understood that while various embodiments have been described in detail with respect to certain illustrative and specific embodiments thereof, the present disclosure should not be considered limited to such, as numerous modifications and combinations of the disclosed features are possible without departing from the scope of the following claims.