GAS DISPLAY PANEL WITHOUT EXHAUST TUBE STRUCTURE

• US 3,778,126 A
• Filed: 12/30/1971
• Issued: 12/11/1973
• Est. Priority Date: 12/30/1971
• Status: Expired due to Term

• Current Assignee: Donald Miller Wilson
• Original Assignee: Donald Miller Wilson
• Inventors: Wilson, Donald Miller
• Primary Examiner(s): Lanham, Charles W.
• Assistant Examiner(s): Davie, J. W.
• Application Number:
  US05/214,174
• Time in Patent Office: 712 Days
• Field of Search: 316/19,20 315/169R 313/109.5,182,220 29/63B
• US Class Current: 445/25
• CPC Class Codes: H01J 9/261 the vessel being for a flat panel display for flat discharge lamps H01J9/268

Abstract

Projecting exhaust tube constructions of earlier gas panels are eliminated by the disclosed process. In the present method an unfused low-softening-point glass sealant, arranged in a picture frame pattern, is sandwiched loosely between aligned flat glass plates, and the disjoint assembly is placed in a vacuum oven enclosure. The enclosure is successively evacuated, filled with the requisite gas mixture at predetermined pressure and heated above the softening point of the sealant to establish a sealed gas-filled envelope within the assembly. Previously the plates have been joined initially by heat fused sealant to form an envelope which is thereafter evacuated and filled with gas by connection to a thin glass tubular orifice projecting from one of the plates. Manipulation of this tube for evacuation and gas back-filling of the envelope, which is a difficult operation requiring considerable time, technique and skill, is eliminated by the present method.

Claims

1. A process for constructing a gas discharge display device devoid of gas-filling ducts or tubulations, comprising:

assembling discrete parts - including a pair of transparent dielectric support plates bearing dielectric coated conductive circuits in a spaced apart unfused configuration with uniform spacing between the unfused plates established by a heat fusible sealing material of generally uniform thickness arranged in an enclosure shape of predetermined form in an unfused condition, said sealing material having a pedetermined softening temperature substantially lower than the softening temperatures of said plates - to form an enclosed space which is relatively permeable to gas flow at a boundary between said sealing material and said plates;

providing spacer elements within said enclosed space having thickness dimensions establishing a predetermined limiting dimension within said space less than the thickness of said unfused sealing material;

said elements having softening temperature substantially higher than that of the sealing material;

filling said enclosed space, with an ionizable gas suited for display usage, by exposing said assembled parts to an atmosphere of said gas at predeterminEd pressure; and

heating said assembled parts with said enclosed space filled with and retaining said gas, over a temperature range exceeding the softening point of the sealing material but below the softening points of said support plates and spacer elements, to cause selective softening of said sealing material with resulting fusion of said sealing material, dielectric circuit coatings and plates into a sealed unit impermeably confining a predetermined volume of said gas between said circuits in an envelope space of predetermined uniform height dimension established by said spacer elements.

2. A process according to claim 1 wherein said step of filling said space is accomplished by successively evacuating a volume of space containing said unfused assembled parts and filling said containing volume of space with said gas at said predetermined pressure while maintaining said volume at a temperature below the softening temperature of said sealing material.

3. A process for constructing ductless gas discharge display devices comprising in succession:

arranging transparent flat glass plates, bearing orthogonally oriented printed circuit conductors encapsulated in transparent dielectric films, in substantially parallel spaced apart orientation with initial spacing determined by an enclosed strip of heat fusible envelope sealing material in unfused condition and ultimate spacing determined by glass spacer elements thinner than said sealing material;

said material and dielectric films having softening temperatures lower than softening temperatures of said plates and spacer elements;

locating said arranged parts in the interior of a vacuum oven equipped for selective evacuation, gas filling and heating;

evacuating said oven interior while maintaining a temperature therein below the softening temperatures of said sealing material and dielectric films;

filling said oven interior with a gas subject to ionization display usage at predetermined pressure while maintaining temperature in said interior below said sealing material and dielectric film softening temperatures; and

varying the temperature in said oven interior over a range encompassing the said sealing material and film softening temperatures but substantially below the softening temperature of the glass plates and spacer elements to effect selective softening of said sealing material and films and fusion of said sealing material to said plates forming an integral unit impermeably confining an ionization space of predetermined uniform height dimensions determined by said spacer elements, said ionization space filled exclusively with a predetermined volume of said gas at a predetermined pressure.

4. Process of claim 3 wherein said sealing material is arranged initially in a uniformly thick picture frame strip pattern with initial thickness exceeding the desired height dimensions of said ionization space.

5. A process for constructing gas discharge display devices devoid of specialized gas-filling structural projections or tubulations comprising:

arranging components - including transparent flat dielectric support members having predetermined softening temperature and bearing integral printed circuit metallization patterns encapsulated in transparent dielectric film coatings of predetermined thickness, said coatings having predetermined softening temperature, and transparent dielectric spacer rods having predetermined softening temperature assembled in a spaced configuration established by a closed strip of heat fusible sealing material forming a permeable enclosure of a space between said members;

said strip having predetermined generally uniform thickness greater than the diameter of the spacer rods and having predetermined softening temperature less than the softening temperatures of said members, film coatings and spacer rods - within a vacuum oven enclosure;

said spacer rods being located and dimensioned to establish a predetermined limiting spacing between the encapsulAted metallization patterns on said plates upon subsequent softening of said sealing material;

evacuating said oven enclosure with said arranged components located therein and with the temperature thereof maintained below the softening temperature of said sealing material;

filling said oven enclosure with a predetermined gas suited for display usage;

with said gas at predetermined pressure specifically related to the pressure required for display operation and with said enclosure maintained at temperature below the softening point of said sealing material;

uniformly heating said gas-filled oven enclosure, with said gas confined therein, to a selected temperature above the softening points of said sealing material and film coatings but below the softening points of said members, film coatings and spacer rods thus effecting selective softening of said sealing material and fusion of said sealing material to said flat members forming an impermeable gas-filled envelope between said members of predetermined uniform height dimension determined by the thickness of said spacing rods, said envelope sealably confining a predetermined fractional volume of the gas in said oven enclosure at a predetermined elevated pressure; and

restoring said oven enclosure to ambient temperature and atmosphere and pressure conditions.

6. Process according to claim 5 wherein said oven enclosure is maintained at the temperature of the ambient environment surrounding the enclosure during said evacuating and gas filling step.

7. Process according to claim 5 wherein said oven enclosure is pre-heated to a temperature above the temperature of the surrounding ambient and below the softening points of said material prior to said gas filling step, whereby said gas may be introduced at a reduced pressure.

8. A process according to claim 5 wherein a plurality of panels are aggregately assembled in stacked formation to form a three-dimensional display.

9. A process according to claim 6 wherein the evacuating step comprises reducing pressure within said oven enclosure from atmospheric ambient to approximately 10 Torr in approximately 5 minutes and from 10 Torr to between 10 3 and 10 6 Torr in approximately 60 minutes;

and wherein the heating step comprises raising the oven temperature at a rate of between 1* and 3* C per minute to a point sufficient to establish selective softening and complete fusion of the sealing material and the restoring step comprises first cooling the oven enclosure at said rate of 1*-3* C per minute and then restoring ambient atmosphere and pressure to the oven enclosure.

10. A process according to claim 7 wherein the evacuating step comprises reducing the pressure in said oven enclosure from atmospheric ambient to approximately 10 Torr in approximately 5 minutes and from 10 Torr to between 10 3 and 10 6 Torr in approximately 60 minutes;

and said pre-heating step is executed between said evacuating and filling steps by adding heat to produce a temperature rise of between 1*-3* C per minute; and

wherein said heating step comprises adding more heat sufficient to increase the temperature at 1*-3* C per minute to a value above the selective softening point of the sealing material before initiating ambient cooling and re-pressurization.