Field
The present specification generally relates methods and apparatuses for conveying flexible glass substrates and, more specifically, to methods and apparatuses for minimizing contact between flexible glass substrates and roller elements as the flexible glass substrates are conveyed and redirected.
Technical Background
Thin flexible glass substrates can be used in a variety of applications, including so-called “e-paper,” color filters, photovoltaic cells, displays, OLED lighting, and touch sensors. The glass for such substrates can be quite thin, typically less than about 0.3 mm. The processing of the substrates can be performed on an individual glass sheet basis, or most efficiently, by conveying the substrate as a long glass ribbon, or web, wound on a roll, or spool. Such methods include dispensing the ribbon from one roll, processing the dispensed portion, then re-winding the ribbon onto a take-up roll. Alternatively, the glass ribbon can be singulated into discrete components or sheets instead of the final re-winding onto a take-up roll.
One drawback to a so-called “roll-to-roll” process is the brittleness of the thin glass ribbon. Specifically, mechanical contact of the ribbon during handling can lead to damage, including scratches, chipping, and fracture. What is needed are methods and apparatuses for conveying the flexible glass substrate without damaging the glass or any fabricated device structures that may exist on the glass surfaces.
The embodiments described herein relate to methods and apparatuses for conveying and redirecting a flexible glass ribbon assembly while minimizing the likelihood of damage to the glass ribbon assembly or any fabricated device structures on the glass surfaces as the glass ribbon assembly is redirected from a first plane into a second plane. Specifically, the methods and apparatuses described herein prevent contact between the flexible glass substrate or device structures and roll members of a conveying apparatus thereby reducing the likelihood of damage to the flexible glass substrate or fabricated devices during handling and processing.
According to one embodiment, a method of redirecting a glass ribbon assembly to avoid contact with a glass substrate of the glass ribbon assembly or fabricated device includes conveying the glass ribbon assembly structures in a conveyance direction on a first glass conveyance path. The glass ribbon assembly includes a flexible glass substrate having a first surface and a second surface that extend laterally between a first edge and a second edge, a first handling tab affixed to the first edge, and a second handling tab affixed to the second edge. The first handling tab and the second handling tab extend above and below the flexible glass substrate and define a handling surface envelope in which the flexible glass substrate is positioned when the first surface and the second surface are planar. The method also includes supporting the glass ribbon assembly on the first handling tab and the second handling tab such that the flexible glass substrate is free to flex out of the handling surface envelope while remaining spaced apart from a primary roll member when the flexible glass substrate is directed around the primary roll member. The method further includes directing the glass ribbon assembly around the primary roll member such that the glass ribbon assembly is redirected from the first glass conveyance path to the second glass conveyance path.
In another embodiment, an apparatus for redirecting a glass ribbon assembly to avoid contact with a glass substrate of the glass ribbon assembly or fabricated devices includes a glass ribbon assembly source which provides a glass ribbon assembly that includes a flexible glass substrate having a first surface and a second surface that extend laterally between a first edge and a second edge, a first handling tab affixed to the first edge, and a second handling tab affixed to the second edge. The first handling tab and the second handling tab extend above and below the flexible glass substrate and define a handling surface envelope. The apparatus also includes a primary roll member located downstream of the glass ribbon assembly source. The primary roll member includes a first cylindrical contact surface and a second cylindrical contact surface spaced apart from the first cylindrical contact surface along a roller element axis. The flexible glass substrate of the glass ribbon assembly is free to flex out of the handling surface envelope while remaining spaced apart from the primary roll member. The apparatus further includes a first glass conveyance path extending from the glass ribbon assembly source to the primary roll member. The first cylindrical contact surface and the second cylindrical contact surface of the primary roll member are positioned to be tangential to the first glass conveyance path. The apparatus also includes a second glass conveyance path extending from the primary roll member in a downstream direction. The first cylindrical contact surface and the second cylindrical contact surface of the primary roll member are tangential to the second glass conveyance path and the second glass conveyance path is non-planar with the second glass conveyance path.
In yet another embodiment, a method of redirecting a glass ribbon assembly to avoid contact with a glass substrate of the glass ribbon assembly or fabricated device includes conveying the glass ribbon assembly in a conveyance direction on the first glass conveyance path. The glass ribbon assembly includes a flexible glass substrate having a first surface and a second surface that extend laterally between a first edge and a second edge. The first surface and the second surface define a handling surface envelope in which the flexible glass substrate is positioned when the first surface and the second surface are planar. The method also includes supporting the glass ribbon assembly on a primary roll member that includes a first cylindrical contact surface and a second cylindrical contact surface spaced apart from the first cylindrical contact surface along a roller element axis. The glass ribbon assembly is supported by the first and second cylindrical contact surfaces at positions proximate to the first edge and the second edge of the flexible glass substrate. The flexible glass substrate is free to flex out of the handling surface envelope while remaining spaced apart from a primary roll member at positions between the first cylindrical contact surface and the second cylindrical contact surface when the flexible glass substrate is directed around the primary roll member. The method further includes directing the glass ribbon assembly around the primary roll member such that the glass ribbon assembly is redirected along from the first glass conveyance path to the second glass conveyance path.
Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows, the claims, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.
Reference will now be made in detail to embodiments of methods and apparatuses for conveying and redirecting flexible glass substrates, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. In one embodiment, a method of redirecting a glass ribbon assembly includes conveying the glass ribbon assembly along a first glass conveyance path. The glass ribbon assembly comprises a flexible glass substrate that includes a first surface and a second surface that extend laterally between a first edge and a second edge. First and second handling tabs are affixed to the first and second edges. The handling tabs extend above and below the flexible glass substrate and define a handling surface envelope in which the flexible glass substrate is positioned when the first surface and the second surface are planar. The glass ribbon assembly is supported on the first and second handling tabs such that the flexible glass substrate is free to flex outside of the handling surface envelope while remaining spaced apart from a primary roll member when the flexible glass substrate is directed around the primary roll member. For example, the handling tabs together create a gap between the flexible glass substrate and the roll member. The method further includes directing the glass ribbon assembly around a primary roll member such that the glass ribbon assembly is redirected from the first glass conveyance path to the second glass conveyance path. The methods of redirecting a glass ribbon assembly from a first glass conveyance path to a second glass conveyance path and apparatuses for performing the method will be described in further detail herein with specific reference to the appended drawings.
While glass is generally known as a brittle material, inflexible and prone to scratching, chipping and fracture, glass having a thin cross section can in fact be quite flexible. Glass in thin sheets or ribbons can be wound and un-wound from rolls, much like paper or plastic film. However, even though glass can be made flexible, it retains its brittle characteristic, and can be damaged by contact. For certain applications, particularly those for which visual defects can be distracting (e.g., display applications), even minor, seemingly cosmetic defects are unacceptable. For other applications requiring high mechanical strength, defects even less than 1 μm can limit the mechanical reliability of the glass substrate. Thus, handling of the glass substrates during a manufacturing process, such as the deposition of thin film coatings onto the glass substrate, can become a source of loss and high cost. Additionally, as device structures are fabricated on the flexible glass surfaces, contact with the device structures can result in damage to the device structures and significant reduction in manufacturing yield.
In order to minimize contact with the glass substrate or device structures fabricated on the glass surfaces during roll-to-roll or sheet-fed roll processing, handling tabs may be attached to the edges of a flexible glass substrate, as described in U.S. patent application Ser. No. 12/511,167 entitled “F
While the handling tabs make it possible to prevent contact with the surface of the flexible glass substrate during most processing and/or manufacturing operations, the present inventors have determined that the handling tabs may not prevent all contact with the glass surface or devices structures fabricated on the glass surfaces during processing. Specifically, as a flexible glass substrate is redirected through different processing stages, one or more rollers may be utilized to convey the flexible glass substrate from stage to stage and redirect the flexible glass substrate along different glass conveyance paths. The present inventors have determined that as the flexible glass substrate with handling tabs transitions from a flat or planar state to a curved state, such as when the flexible glass substrate is redirected around a cylindrical roller, the center portion of the flexible glass substrate may flex and may make contact with the roller, potentially damaging the surface of the flexible glass substrates. Additionally, instabilities, perturbations, vibrations, and transient effects that may exist in manufacturing environments or in processing and handling equipment may also cause intermittent or extended contact to occur between flexible glass substrate and the roller handling system. The methods and apparatuses described herein mitigate contact between the flexible glass substrate or device structures fabricated on the glass surfaces and the roller during handling, including where the flexible glass substrate transitions from a planar state to a curved state around a roller.
Although glass can be processed on an individual sheet basis, “roll-to-roll” processing of the glass ribbon allows for an efficient method of processing that involves starting with a glass ribbon assembly paid out from a glass ribbon assembly source. For example, the glass ribbon assembly source may include the glass ribbon assembly wound on a pay-out roll, as depicted in
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While the methods and apparatuses described herein may be used in roll-to-roll processing of glass substrates, it should be understood that other applications are possible. For example, the methods and apparatuses may be used in conjunction with a glass manufacturing apparatus.
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The delivery vessel 325 supplies the molten glass 326 through a downcomer 330 into the FDM 341. The FDM 341 comprises an inlet 332, a forming vessel 335, and a pull roller assembly 340. As shown in
As the flexible glass substrate 92 exits the pull roller assembly 340, the molten glass solidifies. In one embodiment, after the molten glass solidifies and cools, the flexible glass substrate 92 may be directed into a cutting device, such as a laser cutting device 350, which removes edge beads 352 formed on the flexible glass substrate 92 during the formation process by laser separation. However, it should be understood that this step is optional and that in other embodiments (not shown) the edge beads 352 may be left in place on the flexible glass substrate 390.
The flexible glass substrate 92 is then directed into a tab applicator 301 where an adhesive tape ribbon may be applied to the first and second edges 93, 94 of the flexible glass substrate 92. Upon exiting the tab applicator, handling tabs 95, 96 may be formed on the lateral edges 93, 94 of the flexible glass substrate 92 to create a glass ribbon assembly 90 and to facilitate handling the glass ribbon assembly 90 during downstream processing operations. Thereafter, the glass ribbon assembly 90 may be conveyed into apparatus 100 through additional downstream processing steps as described hereinabove. Accordingly, in this embodiment, the processing equipment upstream of the apparatus 100 can be collectively referred to as the glass ribbon assembly source.
It should now be understood that methods and apparatuses for conveying a glass ribbon assembly according to the present disclosure include primary roll members that support a glass ribbon assembly on first and second handling tabs positioned at the edges of the flexible glass substrate. The upper and lower surfaces of the handling tabs define a handling surface envelope. As the glass ribbon assembly is conveyed along a conveyance path and redirected from a first path to a second path around a primary roll member, the flexible glass substrate is free to flex outside of the handling surface envelope while remaining spaced apart from the primary roll member. Accordingly, by maintaining spacing between the flexible glass substrate and the primary roll member as the glass ribbon assembly is redirected, damage to the flexible glass substrate may be minimized. The purpose of the roll member design is to prevent contact between flexible glass substrate or device structures that are fabricated on the glass surfaces and the roll member. The roll member can act alone to redirect the glass direction. Alternatively, the roll member can be used to initiate or to complete a curved path of the glass ribbon assembly. The curved path initiated or completed with the roll member may then continue over other rollers placed in proximity to the roll member. It should be understood that the most likely location for contact between the flexible glass substrate and the roll member is in a location proximate to the transition of the glass ribbon assembly between a flat shape and a curved shape. When the glass ribbon assembly is conveyed in a straight direction, the flexible glass substrate may have a tendency to sag or bow. This deflection may be exacerbated or caused by instabilities in the overall mechanical system. The roll member design prevents or minimizes contact between the flexible glass substrate and the roll member. As the direction of glass conveyance between the roll member and other rollers in proximity to the roll member is along a conveyance path that is curved, the likelihood of contact is reduced. Further, any or all portions of the roll member may include a fluid support device, as described hereinabove.
Variations of the concept of use include the use of roll member designs in sheet-fed roller conveyance equipment configurations. Further, while handling tab configurations that are positioned above and below the flexible glass substrate were described above, other handling tab designs are contemplated. Use of roll members according to the present disclosure with a flexible glass substrate that does not include handling tabs is possible. In such applications, contact between the flexible glass substrate and the roll member is permissible along the edges of the flexible glass substrate, while the central portion of the flexible glass substrate remains free from contact with the roll members.
It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus it is intended that the specification cover the modifications and variations of the various embodiments described herein provided such modification and variations come within the scope of the appended claims and their equivalents.
This is a divisional of U.S. patent application Ser. No. 13/307,235 filed on Nov. 30, 2011, the content of which is relied upon and incorporated herein by reference in its entirety, and the benefit of priority under 35 U.S.C. §120 is hereby claimed.
Number | Name | Date | Kind |
---|---|---|---|
1569724 | Dimond | Jan 1926 | A |
2595325 | Baumgartner | May 1952 | A |
5585188 | Cheron et al. | Dec 1996 | A |
5967394 | Crowley et al. | Oct 1999 | A |
6032843 | Juergens, III | Mar 2000 | A |
6668473 | Schoening | Dec 2003 | B2 |
7017853 | Colson et al. | Mar 2006 | B2 |
9034458 | Li | May 2015 | B2 |
20100260964 | Nakamura et al. | Oct 2010 | A1 |
20110023548 | Garner et al. | Feb 2011 | A1 |
20110177325 | Tomamoto et al. | Jul 2011 | A1 |
20110223386 | Tomamoto et al. | Sep 2011 | A1 |
20120247154 | Abramov | Oct 2012 | A1 |
20120255672 | Marshall et al. | Oct 2012 | A1 |
20130134202 | Garner | May 2013 | A1 |
Number | Date | Country |
---|---|---|
1969009701 | May 1969 | JP |
62036263 | Feb 1987 | JP |
2001196438 | Jul 2001 | JP |
2006206320 | Aug 2006 | JP |
2011178490 | Sep 2011 | JP |
2006121709 | Nov 2006 | WO |
Entry |
---|
Byon et al.; “Effect of roll gap adjustment on exit cross sectional shape in groove rolling—Experimental and FE analysis”; Journal of Materials Processing Technology 209 (2009); pp. 4465-4470. |
Japanese Patent Office; Notice of Grounds for Rejection for Japanese Application No. 2014-544907; Issue Date: Aug. 2, 2016; pp. 1-5. |
Number | Date | Country | |
---|---|---|---|
20160185545 A1 | Jun 2016 | US |
Number | Date | Country | |
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Parent | 13307235 | Nov 2011 | US |
Child | 15060714 | US |