CA1229868A

CA1229868A - Display panel and method of making it

Info

Publication number: CA1229868A
Application number: CA000453301A
Authority: CA
Inventors: Philip Kuznetzoff
Original assignee: Burroughs Corp
Current assignee: Unisys Corp
Priority date: 1983-05-02
Filing date: 1984-05-01
Publication date: 1987-12-01
Also published as: JPS59209243A; EP0124099A3; EP0124099B1; EP0124099A2; DE3474230D1; US4534744A

Abstract

ABSTRACT OF DISCLOSURE
DISPLAY PANEL AND METHOD OF MAKING IT

The method of making a display panel 10 comprising forming an assembly of a glass base plate having a set of longitudinal first slots in which anode electrodes are secured and having an array of cathode electrodes seated on the top surface of the base plate and oriented transverse to the anodes. An apertured electrode plate is disposed adjacent to the base plate and its electrodes, and a face plate assembly is prepared by providing a glass plate and forming on one surface, in order, a large-area electrode and one or more insulating layers, after which an apertured insulating layer is formed thereon by a photo-etching process. The face plate assembly carrying the apertured insulating layer is assembled with the other parts of the panel, and the panel is processed to completion.

Description

DISPLAY PANEL AND METHOD OF ~AKING IT

BACKGROUND OF THE INVENTION
-A recently invented display panel which comprises a dot matrix display having memory is relatively complex and includes several support plates, insulating layers, and electrode arrays which must be prepared and assembled accurately.
. The present invention relates to improvements in the panel which simpliiy its prepara-tion.

DESCRIPTIO~ OF THE DRAWINGS
. .
Fig. l is a perspective exploded view of 2 display panel.embodying the invention;
Fig. 2 is a sectional view through the panel of Fig. 1 along lines 2-2, with the panel shown assembled;
Fig. 3 is a sectional view of a portion of ~he face place of the panel of Eig. 1 at oRe stage in che manufacture of the face pLate assembly; and `

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Fig. 4 is a perspective view of the assembly of Fig. 3 at a later stage in its preparation and ready for assembly with other parts of the display panel.

DESCRIPTION OF THE INVENTION
The present invention is used to manufact~re a dot matrix memory display panel including a D.C. scan/
address portion and an A.C. display portion.

The display panel 10 lncludes a gas~Eilled envelope made up of an insulating base plate or substrate 20 and a glass race plate 30, which are hermetically sealed together, as illustrated in Fig. ~, along a closed periphery which surrounds the operating inner portion of the panel and the various gas cells provided therein. The base plate has a top surtace 22, in which a plurality or relatively deep parallel, longitudinal slots 40 are Eormed and in each of ~hich a scan/address anode electrode~ Eor example a wire 50, is seated and secured.
A plurality o~ scan cathode elect,odes, in the form of wires or strips, are seated on che top s~rtace of the base plate or in shallow slots 70 cherein. The scan cathodes 60 are disposed transverse to the sc~n anodes 50, and each crossing o~ a scan cathode 60 and a scan anode 40 defines a scanning celi 72 ~Fig. 2). I~
can be seen that the scanning cells are arrayed in ro~s and columns. ~lore specifically, the cachode ?orciQrls 61, the underLying portions of anodes 50, and the intermedia~-e gaseous regions deLine the scanning ceils.

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The scan cathodes 60A, B, C, etc., form a series of cathodes which can be energized serially in a scanning cycle, with cathode 60A being the first cathode energized in the scanning cycle.
A reset cathode electrode 62 is disposed in a slot 64 in the top surface of the base plate adjacent to the first sc~n cathode 60A, so that, when it is energized, it provides excited particles for cathode 60~ at the beginning of a scanning cycle to be described. l~here the reset cathode crosses each scan anode, a reset cell is formed, and the crossing of all of the scan anodes by the reset cathode provides a column o~ reset cells. These reset cells are turned on or energized at the beginning of each scannin~ cycle, and they expedite the turn-on of the first column o~ scanning cells associated wich the first cathode 60A.
The panel lO includes a suitable keep-alive arran~ement, one form of which is described below and in U. S. Patent No. 4,329,616 of George E. Holz and James A. Ogle.
In the panel lO, a spacer means comprising strips 74 of insulating material, such as glass, are provided on the top surface or the insulating plate ~0 and on cathodes 60 and 62 so chat the cathodes are 2S spaced uniformly from an electrode plate 80 disposed above them, as described below. The s.rips 74 are disposed across the cathodes 60 which are thus separated into discrete operating portions.
The portions of the panel described up to this point comprise the base plate assembly. This is che D.C.
portion and the scanning and addressing portion ot the panel.
Adjacent to the base plate assembly is the second portion of the panel which is a quasi A.C.
assembly; that is, it includes A.C. and D.C. features.

_4~ 3~3 This portion of the panel includes an electrode in the form of a thin metal plate 80 (known as the priming pla~e) having an array of rows and columns of relatively small apertures 92, each overlying one of the scanning cells. The plate 80 is positioned close to cathodes 60 and may be seated on insulating sheet 74. Electrode plate 80 includes a terminal 88 for making electrical connection thereto.
Adjacent to plate 80, and preferably in contact with the upper surface thereof, is an apertured plate or layer 86 (known as the glow isolator) having rows and columns of apertures 94 which are considerably larger than apertures 92. The apertures 94 comprise the display cells of panel 10. The sheet 86 may be of insulating material, as shown in Fig. ~, or it may be of metal, and, if it is of metal, the plates 80 and 86 may be made in one piece.
The quasi A.C. assembly also includes a face plate assembly which includes a single large-area transparent conductive electrode lO0 on the inner surface of the plate 30. A narrow conductor 110, which outlines and reinforces the electrode layer lO0 in conductive contact, serves to increase its conductivity, if necessary. The conductor llO includes a suitable tab L14, to which external connection can be made. The large-area electrode 100 is of sufficient area to overlie the entire array of display cells 94 in plate 86. An insulating coating 120 of glass or the like covers electrode 100.
3~) Under some circumstances, it is desirable to coat the glass layer 120 with a low work function reEractory layer 132 of magnesium oxide~ thorium oxide, or the like.
In panel lO, the apertures 94 in pla~e 86 comprise display cells, and, as can be seen in Fig. 2, each display cell has one end ~all 134 formed by a portion of insulating layer 132, and an opposite end wall 136 formed by a portion of the top surface of plate 80. Io provide cell uniformity and to minimize sputtering, a coating of the material of layer 132 should also be provided on the base or lower wall 136 of each display cell 94, such as the layer 133 shown in Fig. 2.
Panel 10 has a keep-alive arrangement, referred to above, which includes an A.C. electrode 140 in the form of a linear conductive fiLm or layer of opaque metal, such as silver provided on the inner surface of the face plate 30 adjacent to one edge of the transparent conductive electrode 100. The A.C.
keep-alive electrode 140 is positioned so that it is in optimum operative relation with the column of reset cells and reset cathode 62, to which it supplies excited particles. The A.C. keep-alive eleccrode 140 is covered by the insulating layers 120 and 132. The pla~e 86 is provided with a slot 142, and plate 80 i5 provided with a column of holes 150, the 510t 142 overlying and being aligned wieh the column of holes 150, and both lie beneath and are aligned with the A.C. electrode 140.
The slot 142 in the plate 36 is narrower than che opaque A.C. electrode 140 so tha~ a viewer, looki.ng ~hrough face plate 30, cannot see any glow which is present in slot 142 and holes 150. Electrode 140 operates wich pLa~e 80 to produce glow discharge bet~een them and produce exci.ted partlcles in slot 14~ and hoies 150.
These excited particles are available to the reset cathode 62 and assist the firing o the columll of reset cells.
The gas filling in panel 10 is prer-erably a Penning gas mlxture of, for example, neon and a small percentage of xenon, at a pressure of about 400 Torr.

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When the panel has been constructed and evacuated~ the gas filling is introduced through a tubulation 24 secured to base plate 20 (Fig. 2), or a non-tubulated construction can be employed.
In making the panel 10, the base plate assernbly, including glass base plate 20, anodes ~0, cathodes 60, and insulating strips 74, are prepared in any suitable manner, for examPle. as described in ~. S. Patent No.

4,352,050 of Nicholas C. Andreadakis. Pla-te 80 is a plate of any suitable metal in which the holes 92 and 150 are formed ~y laser drilliny or in any other suitable manner. The face plate and the electrode 100 and ring 113 and glass layer 120 and magnesium oxide layer 132 are prep~red in any well known manner.
According to the invention, reEerring ~o Figs. 3 and 4, the glow isolator plate a6 is prepared on the layer 132 on the face plate. The invention can be carried out with several materials and appro~riate process steps. For example, one material is Fotoorm Q , a Corning product which is available in the form o~ a thin plate which is secured to the lower surface oÇ the face plate and chen is exposed chrough a suita~le mas'c and developed with heat to form a pactern of crystallized regions in the plate. When the plate is then contac~ed with a solvenc, such as dilute hydro~luoric acid~ ~he crystallized regions are removed, and this leaves the desired glow isolator place B6 on the face J~Late.
Another usable material is Fodel ~ , a DuPont product, which is a photopolymer available in the form of a paste containing certain fillers, in this case, glass fillers. The paste material is spread on ~he lower surface of the face place to torm a layer which is exposed and developed and processed with a spray of 1, 1, 1 trichloroethane to remove the une~posed portions ~7~

and this leav~sapertured plate 86.
Another usable material is also a DuPont product known as Riston ~ . This is a photopolymer which comes in sheets, and a length is secured to the lower surface of the base plate. The applied layer is then exposed and developed and etched in 1, 1, 1 trichloroethane to leave an array of islands of Riston in a pattern which is the reverse of the pattern of apertures 94 in the glow isolator plate; that is, there are islands of Riston where the apertures 94 are in the completed glow isolator. A layer of glass or ceramic is then applied to the Riston layer, and the remains of the Riston layer are etched out with the same etchant to leave the desired apertured glow isolator plate 86.
After this face plate assembly has been prepared, all oi the panel parts are then assembled and processed to completivn.

Claims

What is claimed is:

1. The method of making a display panel comprising the steps of forming a plurality of relatively deep parallel, longitudinal first slots in a glass base plate having a top surface, upper and lower edges, and left and right ends, securing an anode electrode in each of said first slots, providing a plurality of cathode electrodes adjacent to the top surface of said base plate oriented generally transverse to said anode electrodes, said cathode electrodes crossing said anode wires and forming a first glow cell at each crossing, said first glow cells being disposed in rows and columns in a first layer, placing means comprising strips of insulating material on said base plate overlying said cathodes, mounting an electrode plate on said base plate, said electrode plate having an array of small holes, each of which overlies one of said first glow cells, mounting on said electrode plate, a face plate carrying an apertured insulating layer, said apertured insulating layer having an array of apertures comprising display cells, each of which overlies one of said small holes, and hermetically sealing together all of said parts to form the completed panel and filling the panel with an ionizable gas.

2. The method of making a display panel comprising the steps of forming a plurality of relatively deep parallel, longitudinal first slots in a glass base plate having a top surface, upper and lower edges, and left and right ends, securing an anode electrode in each of said first slots, providing a plurality of cathode electrodes adjacent to the top surface of said base plate oriented generally transverse to said anode electrodes, said cathode electrodes crossing said anode wires and forming a first glow cell at each crossing, said first glow cells being disposed in rows and columns in a first layer, placing means comprising strips of insulating material on said base plate overlying said cathodes, mounting an electrode plate on said base plate, said electrode plate having an array of small holes, each of which overlies one of said first glow cells, preparing a face plate assembly made up of a glass plate having two surfaces, on one of which is formed a large-area transparent electrode covered by a thin layer of glass which is covered by a second insulating layer and a third insulating layer having an array of apertures therein, mounting said face plate assembly on said electrode plate with the apertures in said third insulating layer aligned with the small holes in said electrode plate, and hermetically sealing together all of said pares to form the completed panel and filling the panel with an ionizable gas.

3. The method defined in Claim 2 wherein said third insulating layer in said face plate assembly is prepared by forming on the bottom surface of a glass plate, in order, first a large-area transparent electrode, second a layer of glass, and third a layer of insulating material, providing a layer of photosensitive material on said third layer, exposing said layer in a pattern and developing said pattern in said layer to render portions thereof resistant to removal, and removing portions of said layer to leave an apertured insulating plate which is said third insulating layer.

4. The method of making a display panel comprising the steps of forming a plurality of relatively deep parallel, longi-tudinal first slots in a glass base plate having a top surface, securing an anode electrode in each of said first slots, providing a plurality of cathode electrodes adjacent to the top surface of said base plate oriented gener-ally transverse to said anode electrodes, said cathode electrodes crossing said anode wires and forming a first glow cell at each crossing, said first glow cells being disposed in rows and columns in a first layer, placing means comprising strips of insulating material on said base plate overlying said cathodes, mounting an electrode plate on said base plate, said electrode plate having an array of small holes, each of which overlies one of said first glow cells, preparing a face plate assembly made up of a glass plate .

having two surfaces, on one of which is formed a large-area transparent electrode covered by a thin layer of glass which is covered by a second insulating layer and a third insulating layer having an array of apertures therein, mounting said face plate assembly on said electrode plate with the apertures in said third insulating layer aligned with the small holes in said electrode plate, and hermetically sealing together all of said parts to form the completed panel and filling the panel with an ionizable gas, said third insulating layer in said face plate assembly being prepared by forming on the bottom surface of a glass plate, in order, first a large-area transparent electrode, second a layer of glass, and third a layer of insulating material, providing a layer of photosensitive material on said third layer, exposing said layer in a pattern and developing said pattern in said layer to render portions thereof resistant to removal, removing portions of said layer to leave an apertured insulating plate which is the reverse of said third insulating layer and has solid material where said third insulating layer has apertures, providing areas of insulating material in the apertures in said insulating plate, and removing all of apertured insulating plate to leave said areas of insulating material which comprise said third layer of insulating material.

5. The method defined in claim 4 wherein the material provided in said apertures is a glass.

6. The method of making a display panel comprising the steps of forming a plurality of relatively deep parallel, longi-tudinal first slots in a glass base plate having a top surface, securing an anode electrode in each of said first slots, providing a plurality of cathode electrodes adjacent to the top surface of said base plate oriented generally transverse to said anode electrodes, said cathode electrodes crossing said anode wires and forming a first glow cell at each crossing, said first glow cells being disposed in rows and columns in a first layer, placing means comprising strips of insulating material on said base plate overlying said cathodes, mounting an electrode plate on said base plate, said electrode plate having an array of small holes, each of which overlies one of said first glow cells, preparing a face plate assembly made up of a glass plate having two surfaces, on one of which is formed a large-area transparent electrode covered by a thin layer of glass which is covered by a second insulating layer and a third insulating layer having an array of apertures therein, mounting said face plate assembly on said electrode plate with the apertures in said third insulating layer aligned with the small holes in said electrode plate, and hermetically sealing together all of said parts to form the completed panel and filling the panel with an ionizable gas, said third insulating layer in said face plate assembly being prepared by forming on the bottom surface of a glass plate, in order, first a large-area transparent electrode, second a layer of glass, and third a layer of insulating material, providing a layer of photosensitive material on said third layer, forming an array of apertures in said layer of photosensitive material, filling said apertures with glass, and removing said layer of photosensitive material to leave an array of spaced-apart glass bodies which define apertures which are the display cells in said third layer.