Abstract:
A method of fabricating spacers for use in a flat panel device includes: preparing a core glass having a low solubility in a chemical etching solution and a tube glass having a high solubility in the chemical etching solution and having a larger inner diameter than an outer diameter of the core glass; inserting the core glass into the tube glass to obtain a cylindrical glass; drawing the cylindrical glass at a predetermined temperature until the core glass has a predetermined diameter; cutting the drawn cylindrical glass to a predetermined length; and removing the tube glass in the cylindrical glass using the chemical etching solution.

Description:
CLAIM OF PRIORITY 
     This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. § 119 from an application entitled METHOD OF FABRICATING SPACERS AND METHOD OF INSTALLING SPACERS IN FLAT PANEL DEVICE, earlier filed in the Korean Intellectual Property Office on 11 Aug. 2004 and there duly assigned Serial No. 10-2004-0063092. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method of fabricating cylindrical spacers used in a flat panel device and a method of installing the spacers on a substrate of the flat panel device. 
     2. Description of the Related Art 
     In a flat panel device, spacers are used to provide a vacuum area between a front substrate and a rear substrate. Flat panel devices that use such spacers include Liquid Crystal Displays (LCDs) and Field Emission Displays (FEDs). 
     The spacers must have an insulating property since they support the front substrate and the rear substrate and are in contact with the substrates and must have a sufficient stiffness to resist a pressure difference between the inside and the outside of the flat panels resulting from the high vacuum area inside the flat panels. 
     A spacer can have a flat rod shape and is placed across a display. The spacer can also have a grating shape or a cylindrical shape. 
     A spacer having a rod shape or a grating shape can be fabricated using a laser cutting method or a patterning method. 
     However, a spacer having a cylindrical shape cannot be easily manufactured and installed in a flat panel device. 
     SUMMARY OF THE INVENTION 
     The present invention provides a method of fabricating cylindrical spacers using a drawing property of glass. 
     The present invention also provides a method of installing cylindrical spacers on a substrate of a flat panel device in a convenient manner. 
     According to one aspect of the present invention, a method of fabricating spacers is provided, the method comprising: preparing a core glass having a low solubility in a chemical etching solution and a tube glass having a high solubility in the chemical etching solution and having a larger inner diameter than an outer diameter of the core glass; inserting the core glass into the tube glass to obtain a cylindrical glass; drawing the cylindrical glass at a predetermined temperature until the core glass has a predetermined diameter; cutting the drawn cylindrical glass to a predetermined length; and removing the tube glass in the cylindrical glass using the chemical etching solution. 
     The core glass preferably comprises silicate glass including a large amount of PbO. 
     The chemical etching solution preferably comprises hydrochloric or acetic acid. 
     The tube glass preferably comprises BaO—B2O3 based silicate glass. 
     The predetermined temperature is preferably in a range of 650-700 degrees C. 
     The predetermined diameter is preferably in a range of 20-100 micrometers. 
     The predetermined length is preferably 1.1 mm. 
     According to another aspect of the present invention, a method of installing spacers in a flat panel device is provided, the method comprising: preparing a mold having grooves, each groove having a radius corresponding to that of a spacer; disposing each of the spacers in each groove of the mold and assembling another mold on the mold having the spacers disposed therein; disposing the assembled molds on a substrate so that the spacers are vertically arranged on the substrate; and removing the molds from the substrate. 
     Disposing each of the spacers preferably further comprises coating an adhesive on one end of each of the spacers; and disposing the assembled molds on the substrate so that the one end of each of the spacers coated with the adhesive contacts the substrate. 
     Each of the molds preferably has grooves on both opposite sides and distances between the grooves respectively correspond to spacing distances between the spacers arranged on the flat panel device. 
     According to yet another aspect of the present invention, a method of installing spacers in a flat panel device is provided, the method comprising: coating a magnetic material on one end of each of the spacers; disposing magnetic dots at positions where the spacers are to be installed on a plate; magnetizing the magnetic material; placing the spacers on the plate and applying a magnetic field to the plate to attach the spacers to the magnetic dots; coating an adhesive on an other end of each of the spacers; aligning the plate on a substrate so that the other end of each of the spacers is attached to the substrate; and removing the magnetic field applied to the plate and separating the plate from the substrate. 
     Distances between the magnetic dots preferably correspond to spacing distances between the spacers arranged on the flat panel device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the present invention, and many of the attendant advantages thereof, will be readily apparent as the present invention becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein: 
         FIG. 1  is a schematic cross-sectional view of a flat panel device; 
         FIG. 2  is a schematic perspective view of the structure of a spacer; 
         FIGS. 3A through 3D  are views of a method of fabricating spacers according to an embodiment of the present invention; 
         FIGS. 4A through 4C  are views of a method of fabricating spacers according to another embodiment of the present invention; and 
         FIGS. 5A through 5D  are views of a method of fabricating spacers according to still another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a schematic perspective view of a structure of a flat panel device.  FIG. 2  is a schematic perspective view of a structure of a spacer used in the device of  FIG. 1 . 
     Referring to  FIG. 1 , spacers  3  are used to provide a vacuum area between a front substrate  1  and a rear substrate  2  in the flat panel device. Flat panel devices that use such spacers  3  include Liquid Crystal Displays (LCDs) and Field Emission Displays (FEDs). 
     The spacers  3  must have an insulating property since they support the front substrate  1  and the rear substrate  2  and are in contact with the substrates  1  and  2  and must have a sufficient stiffness to resist a pressure difference between the inside and the outside of the flat panels resulting from the high vacuum area inside the flat panels. 
     The spacer illustrated in  FIG. 2  has a flat rod shape and is placed across a display. The spacer can also have a grating shape or a cylindrical shape. 
     Hereinafter, a method of fabricating spacers according to an embodiment of the present invention is described in detail with reference to  FIGS. 3A through 3D . 
     Referring to  FIG. 3A , a tube glass  21  which has a high solubility in a predetermined chemical etching solution and a core glass  22  which has a very low solubility in the chemical etching solution are provided. The tube glass  21  has a larger diameter than the core glass  22 . The inner diameter of the tube glass  21  and the outer diameter of the core glass  22  can be about 1-5 mm. Glass used in fabricating a MicroChannel Plate (MCP) can be used for the tube glass  21  and the core glass  22 . For example, BaO—B2O3 based silicate glass can be used for the tube glass  21  and silicate glass containing a large amount of PbO can be used for the core glass  22 . About 1 N hydrochloric acid or acetic acid solution can be used as the chemical etching solution. Compositions of such glasses are disclosed in U.S. Pat. No. 4,112,170. 
     Referring to  FIG. 3B , the core glass  22  is inserted into the tube glass  21  to obtain a cylindrical glass  23 . 
     Referring to  FIG.3C , a plurality of the cylindrical glasses  23  are assembled and drawn at a predetermined temperature, for example, 650-700 degrees C., using a draw machine until the core glass  22  has a desired diameter, for example, 20-100 micrometers. 
     Referring to  FIG. 3D , a plurality of the cylindrical glasses  23 ′ obtained in the previous procedure are cut to a desired spacer length, for example, 1.1 mm. Then, both ends of the cut cylindrical glasses  23 ″ can be polished. 
     Then, the cut cylindrical glasses  23 ″ are immersed into a chemical etching solution, for example, 1 N hydrochloric acid solution to etch the tube glasses  21 . Through this etching procedure, a plurality of spacers, separated from each other, can be obtained. 
     Hereinafter, a method of installing spacers in a flat panel device according to an embodiment of the present invention is described in detail with reference to  FIGS. 4A through 4C . 
     Referring to  FIG. 4A , a mold  40  has grooves  41  into which spacers  30  are inserted. Specifically, each of both opposite sides of the mold  40  has grooves  41  spaced apart from each other by a predetermined distance d 1  and corresponding grooves  41  on both the sides are spaced apart from each other by a distance d 2 . The distances d 1  and d 2  correspond to spacing distances between the spacers  30  respectively actually installed on a flat panel device, in a first direction and a second direction which is perpendicular to the first direction. Distance d 3  can be about 1.0 mm, which is shorter than a length of the spacers  30 , for example, 1.1 mm. 
     Referring to  FIG. 4B , each of the spacers  30  is placed in each of grooves  41  on one side of the mold  40  and another mold  40  is layered on the mold  40  provided with the spacers  30 . After the spacers  30  are placed in the grooves  41 , an adhesive is coated on one end of each of the spacers  30 . 
     Referring to  FIG. 4C , the obtained molds  40  are placed on a substrate  50  so that one end of each of the spacers  30  coated with the adhesive contacts the substrate  50 . Then, the molds  40  are removed to obtain the substrate  50  having the spacers  30  arranged thereon. Such arrangement of the spacers  30  is constantly controlled by the design of the distances d 1  and d 2  during fabrication of the mold  40 . The substrate  50  will be a front substrate or a rear substrate of the flat panel device. Reference numeral  32  denotes a portion in which the adhesive is coated. 
     Hereinafter, a method of installing spacers in a flat panel device according to another embodiment of the present invention is described in detail with reference to  FIGS. 5A through 5D . 
     Referring to  FIG. 5A , a magnetic material  51  is coated on one end of a spacer  50 . Examples of the magnetic material  51  include Fe, Co, Ni, or their alloys or oxides. 
     Referring to  FIG. 5B , magnetic dots  62  are disposed at positions where spacers  50  will be arranged on a plate  60 . A distance between the magnetic dots  62  in a first direction is d 3  and a distance between the magnetic dots  62  in a second direction which is perpendicular to the first direction is d 4 . The magnetic dots  62  can be made of Fe, Co, Ni, or their alloys or oxides. When a magnetic field is applied to the plate  60 , the magnetic dots  62  are magnetized. 
     Referring to  FIG. 5C , the spacers  50  are placed on the plate  60  and when a magnetic field is applied to the plate  60 , the one end of each of the spacers  50  coated with the magnetic material  51  is attached to the magnetic dots  62  by a magnetic force. 
     Then, an adhesive  52  is coated on the other end of each of the spacers  50 . For example, the other end of each of the spacers  50  can be easily coated with the adhesive by placing the plate  60  on the adhesive. 
     Referring to  FIG. 5D , the plate  60  is aligned with a substrate  70  so that the spacers  50  are arranged on the substrate  70 . Then, after the magnetic field is removed, the plate  60  is separated from the substrate  70  and the spacers  50  are attached to the substrate  70 . Such arrangement of the spacers  50  is constantly controlled by the design of the distances d 3  and d 4  during fabrication of the plate  60 . The substrate  70  can be a front substrate or a rear substrate of the flat panel device. Advantageously, the magnetic material  51  on the one end of each of the spacers can be removed therefrom. 
     As explained above, the method of fabricating spacers according to the present invention can provide cylindrical spacers without a complicated patterning process. In addition, the method of installing spacers according to the present invention can facilitate an arrangement of the spacers on a substrate. 
     While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that s various modifications in form and detail can be made therein without departing from the spirit and scope of the present invention as defined by the following claims.