US 3558975 A
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Description (OCR text may contain errors)
United States Patent 4 Claims, 4 Drawing Figs.
us. Cl 316/19 lnt.Cl i. H0lj9/18 FieldofSearch 316/17,]9
 References Cited UNITED STATES PATENTS 2,644,] 13 6/1953 Etzkom 3 16/ 1 9X 2,923,586 2/1960 Anton .t 316/19 2,928,014 3/1960 Aiken et al. 316/19X Primary Examiner-H. A. Kilby, Jr. Attorneys-Kenneth L. Miller and Robert A. Green ABSTRACT: The disclosure is of a multiple gas cell display panel which includes a sandwich of a central apertured plate and top and bottom cover plates, all of glass. The central plate includes apertures arranged in rows and columns which comprise the light-producing cells of the display. The top and bottom plates are of glass and are rigid and the central plate is formed from a flexible strip of powdered glass which is cut to size, has the holes formed in it, and is then sealed in place between the top and bottom plates.
F I 4 INVENTOR.
JAMES A. OGLE wagg ATTORNEY 1 GAS-FILLED MATRIX DISPLAY DEVICES BACKGROUND OF THE INVENTION Display panels of the general type contemplated by the present invention are relatively new, and many problems are still to be solved. One important problem area concerns the central apertured plate which is thin and fragile and includes a large number of tiny holes. It can be readily seen that the making of such a plate and its mating with two other glass plates present difficult problems for a manufacturer.
SUMMARY OF THE INVENTION Briefly, the invention comprises rigid glass top and bottom plates, between which is provided an apertured center plate formed from a flexible sheet of powdered glass. The invention also relates to method of making such devices.
DESCRIPTION OF THE DRAWING In the drawing:
FIG. 1 is a plan view of a device embodying the invention;
FIG. 2 is a sectional view along the lines 2-2 in FIG. 1;
FIG. 3 is an elevational view, partly in section, of apparatus used in practicing the invention; and
FIG. 4 is a sectional view of a portion of a modification of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS A display panel embodying the invention and shown in FIG. 1 includes an apertured central glass plate and top and bottom glass cover plates and 40, respectively. The central plate includes any desired number of apertures or cells 50 which are preferably arranged in rows and columns and are gas-filled and comprise the light-producing members of the display panel.
It is clear that the display panel I0 may be made in any size and may include substantially any number of light-producing gas cells.
In the panel 10, each column of cells 50 is provided with a common column electrode 60, and each row of cells is provided with a common row electrode 70. In one type of device, these electrodes are separated from the gas in the cells and are provided, in one arrangement, on the outer surfaces of the top and bottom plates 30 and 40, as shown in FIG. 1. Of course, the electrodes might be provided on the other surfaces of the glass plates so that they are in contact with the gas in cells 50.
In order to be able to view the glowing gas when cells are fired, at least one set of electrodes, say the column electrodes 60, are made transparent, for example, by making them of thin films of gold or the like, or else they are offset with respect to the cells or properly dimensioned so that the glowing gas in the cells may be viewed.
According to the invention, the center plate 20 is formed from a thin flexible sheet which comprises a thin layer of powdered glass in a binder or on a binder layer such as nitrocellulose or polyvinyl chloride. An auxiliary adhesive might also be included with the glass powder, if necessary. This type of flexible sheet is available commercially from the Vitta Corporation and is known as a glass transfer tape. This product comprises essentially a layer of glass frit secured to a carrier or binder film of a synthetic resinous material, and it may also include a layer of a pressure-sensitive adhesive. The tape is of precise thickness and density, and, on firing, the hinder or carrier and adhesive decompose completely and disappear, and an extremely uniform glass film is provided. The tape is flexible, can
be handled with ease, and can be cut with a scissors to form pieces of any size and shape.
The desired apertures may be formed in the abovedescribed flexible glass sheet in many ways including utlrasonic drilling, punching, or the like. A preferred and relatively simple method according to the invention comprises disposing a sheet of the glass tape 20' (FIG. 3) on a suitable support and then bringing into contact with it a tool having metal rods I20 identical in disposition, number, and
diameter to the size and number and disposition of the apertures to be formed. The tool is pressed into engagement with the strip 20' with sufficient pressure to engage the adhesive or the binder, and, when the tool is removed, the circular areas of the strip which had been contacted thereby adhere to it and are removed. Thus, the desired apertures are formed.
The strip 20' thus treated is positioned between the top and bottom plates 30 and 40 for final processing. The three plates may be held together by the binder or adhesive in sheet 20 or by a suitable jig. The assembly is heated to drive off the binders in sheet 20 and to melt the various glasses sufficiently to forma bond between the three glass plates.
Under some circumstances, the punching mechanism may form holes 50' that are not of uniform diameter from top to bottom, as shown in sheet 20 in FIG. 4. In this case, a second sheet 20" is then secured to a sheet 20', and corresponding holes 50 are formed in the second sheet 20" in line with holes 50'. The two sheets 20 and 20" together then form the center apertured plate of a panel.
The cells in panel 10 are filled with an ionizable gas such as neon, argon, or the like, separately or in mixtures, or in mixtures with gases such as helium or nitrogen. A mixture of about 96 percent neon and 4 percent nitrogen at a pressure of a few hundred mm. Hg is preferred for one type of operation in which the cells 50 have memory. The gas may be introduced during the assembly operation described above if the operation is performed in a vacuum furnace in which the gas atmosphere can be controlled. In another arrangement, the panel 10 is provided with a tubulation (not shown) through which the desired gas filling can be introduced.
Iclaim: l. The method of making a display panel comprising the steps of:
providing a flexible sheet of a thin layer of powdered glass secured to a carrier of a synthetic resinous material;
pressing a plurality of rods into adherent contact with areas of said sheet, removing said rods and thereby removing said areas of said sheet contacted by said rods to leave holes in said sheet;
sealing said sheet between a pair of glass plates; and
filling said holes in said sheet with an ionizable light-producing gas to produce gas-filled cells.
2. The method defined in claim 1 and including, before the step of sealing, the step of heating said sheet to remove vaporizable binders and adhesives.
3. The method defined in claim 1 and including the steps of disposing a first array of electrodes between said sheet and one of said glass plates and disposing a second array of electrodes between said sheet and said other glass plate.
4. The method defined in claim 1 and including the steps of disposing a first array of electrodes between said sheet and one of said glass plates and disposing a second array of electrodes between said sheet and said other glass plate, said first and second arrays of electrodes being disposed at 90 with respect to each other.