CA1041766A - Forming metal coating on parts of operative cathodes in gas discharge panel - Google Patents
Forming metal coating on parts of operative cathodes in gas discharge panelInfo
- Publication number
- CA1041766A CA1041766A CA208,548A CA208548A CA1041766A CA 1041766 A CA1041766 A CA 1041766A CA 208548 A CA208548 A CA 208548A CA 1041766 A CA1041766 A CA 1041766A
- Authority
- CA
- Canada
- Prior art keywords
- cathodes
- layer
- operative
- parts
- panel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Gas-Filled Discharge Tubes (AREA)
Abstract
ABSTRACT:
Before assembling a gas discharge panel the active surfaces of the chromium-containing electrodes which constitute the cathodes are covered with a thin layer of platinum, aluminium or nickel which can prevent the formation of chromium oxide.
Before assembling a gas discharge panel the active surfaces of the chromium-containing electrodes which constitute the cathodes are covered with a thin layer of platinum, aluminium or nickel which can prevent the formation of chromium oxide.
Description
PHN. 7045-The invention relates to a method of manufac-turing a gas disch æge display panel, comprising an insulating base plate and an insulating transparent tup plate, said plates each supporting electrodes con-sisting of a chromium alloy, which electrodes constitu~e the cathodes and anodes for the gas discharges and which plates are secured together while being heated, for example, by means of a sealing glass which is melted. ' The invention further relates to a gas disch æge display panel manufactured by such a method~
It has been found that during melting of the seal-ing glass upon assembling the'panel the electrodes become ; -'' covered with a chromium oxide layer. Such a chromium oxide -layer is favourable indeed for the good adhesion of the electrodes to the glass plates, but the presenoe thereof on the cathodes influences the operating voltages and the ' ignition v~ltages of the gas disch æges. -Cleaning of the'acti~ cathode surfaces after sealing or securing the electrodes to the plates (which usually oonsist of glass) provides little improvement since during heating to melt the sealing glass, a fresh chromium oxide layer'is formed. Mbreover, such deanlng is cumbersome and hence expensive.
According to ~he invention the said drawback is ~-considerably reduced in that at least the parts of the cathodes operative for the gas discharges are covered, prior to assembling the panel, with a metal la~er of a '~
~$ ' .~ '1 ' PHN. 7045- ~
~41~
thickness sufficient to prevent the formation of chro~ium oxide during heating the plates upon assembling ~he panel, the layer consisting of a metal which oxidizes less rapidly than chr ~ium or the oxide of which sputters more rapidly in a gas discharge than chr ~ium oxide.
m e layer may consist of platinum with a -thick-ness of 0.04 /um (400 A). Such a thin platinum la~er has ~ ;
been found to be sufficiently dense to prevent the forma- ; -tion of chromium oxide and can be sputtered in a few hours during the trial period of the panel.
Preferably, a nickel layer or al ~Lnium layer with a thic~ness of 1 to 20 /um is used. This layer is sufficiently dense to prevent the formation of chrcmium oxide. During assembly of the panel the nickel layer or -aluminium layer o~idizes superficially but nickel oxide ~
and aluminium oxide sputter much more rapidly than - -chromium oxide. The remaining nickel or aluminium of the layer need not be removed since this does not present any difficulties for the gas discharge.
The invention will be described in greater detail with reference to the drawing, of which FigL~e 1 is a perspective sectional view of a ~
gas disch~rge display panel, embodying the invention, and i Fig~lre 2 is a sectional view on an enlarged scale of a cathode of ~he panel shown in Figure 1.
Reference numeral 1 in the drawing denotes a base plate and 2 is a top plate consisting of a trans~
' -- 3 - ~ ~
P~. 7045.
7~ ' parent insulating material, in this case glass.
Sealed in the top plate 2 are bar-shaped con-ductors 3 which serve as anodes and which are partly etched away so that channels 6 are formed. The same is the case with the conductors 4 which serve as the cathodes and are sealed in the base plate 1 which consists of glass.
The conductors 3 and 4 consist of an alloy composition of 47.5 weight percent Ni, 47.5 weight percent Fe and 5 weight percent Cr. Since the channels 6' of the base plate and the channels 6 of the top plate cross each other at right angles, cavities of which the height is equal to the sum of --the dep*hs of tWD channels 6 and 6' are formed at the cross- -ings. In said cavities gas discharges may occur by applying suitable potential differences between the crossing anodes 3 and cathodes 4.
m e plates 1 and 2 are secured together b~ means of a readily melting type of glass 8 generally denoted by the te~m "sealing glass".
It has been found that the chromium of the active ' surfaces of the conductors 3 and 4 oxidizes during sealing said conduc~ors in the plates 1 and 2 and during heating of the panel to melt the sealing glass 8, as a result of which a trial test of approximately 30 hours normally has to be carried out after filling the cavities with a suitable gas so as to sputter the chrcmium oxide from the active parts of the cathodes 4 and to obtain constant ignition and operating voltages.
, . ~.. . ~ , . .
PHN. 7045- ~ -~O~ 66 }
According to the invention this is avoided by covering the active surfaces of the cathodes 4, prior to assembly ~f the'panel, with a layer 5 of a metal which oxidizes less rapidly than chromium, or of which the oxide, possibly formed during the melting of the sealing glass, sputters more rapidly than chr~mium oxide. The ~ ' layer 5 must be sufficiently dense to prevent the fo~ma-tion of chromium oxide. However, such a layer 5 should ''~
not be provided on the cathode surfaces which constitute -' the vacuumrtight leadthrGugh of the cathode conductors to the exterior, since a chromium oxide layer promotes the adhesion to the sealing glass. `-A suitable metal is platinum which forms a suffi-cient~y dense layer of a thickness of 0.04 /um to prevent ~ ;
the formation of chromium oxide. After assembly of the panel, the thin platinum layer may be sputtered off in a ~
trial test of a few hours.0wing to the small quantity of '; ;
platinum no difficulties'occur as a result of condensa- ~' tion thereof on the walls of the channels 6 and 6'. '' An even more suitable metal for the'layer 5 is nickel. Although nickel oxidizes superficially upon l' meltin~ the sealing glass 8, said nickel oxide sputters s much more rapidly than~u~#~ chromium oxide. H~wever, ~`;' the nickel layer should bave a mLnimum thickness of 1 to 2 ' /um so as to be suffici~ntly dense, but this is no draw~
back since nickel does not exert a detrimental influence on the gas disch æ ge being itself a suit~ble electrcde `
~. ' 5 ~
', . .
PHN. 7045.
,, , ~
material. So the layer itself need not be sputtered off entirely and may therefore be chosen to be much thicker, for example 20 /um thick. Only the thin surface layer of nickel oxide should be rem~ved from the active cathode surfaces.
Alumunium is also suitable for a layer thickness of 1 to 20 /um. Although this metal also oxidizes during ~-heating ~he panel upon asse~bly,said A1203 layer may be sputtered rapidly, while the remaining aluminium layer ~;
constitutes a suitable cathode sur~ace.
Although several other metals are useful, for :, , , exa~ple, gold and silver, these metals are less suitable ~-than platinum, nickel or aluminium since ~hey have not `;
: :.., only to be provided in thicker layers than aluminium but m~reover thèy have to be sputtered off entirely because they influence the gas discharge. Detrimental dep3sits ~-. . .
may occur on ~he insulating surfaces ketween th conduc ;;
tors so that leakage current can occur and the top plate can beoome opaque.
~,
It has been found that during melting of the seal-ing glass upon assembling the'panel the electrodes become ; -'' covered with a chromium oxide layer. Such a chromium oxide -layer is favourable indeed for the good adhesion of the electrodes to the glass plates, but the presenoe thereof on the cathodes influences the operating voltages and the ' ignition v~ltages of the gas disch æges. -Cleaning of the'acti~ cathode surfaces after sealing or securing the electrodes to the plates (which usually oonsist of glass) provides little improvement since during heating to melt the sealing glass, a fresh chromium oxide layer'is formed. Mbreover, such deanlng is cumbersome and hence expensive.
According to ~he invention the said drawback is ~-considerably reduced in that at least the parts of the cathodes operative for the gas discharges are covered, prior to assembling the panel, with a metal la~er of a '~
~$ ' .~ '1 ' PHN. 7045- ~
~41~
thickness sufficient to prevent the formation of chro~ium oxide during heating the plates upon assembling ~he panel, the layer consisting of a metal which oxidizes less rapidly than chr ~ium or the oxide of which sputters more rapidly in a gas discharge than chr ~ium oxide.
m e layer may consist of platinum with a -thick-ness of 0.04 /um (400 A). Such a thin platinum la~er has ~ ;
been found to be sufficiently dense to prevent the forma- ; -tion of chromium oxide and can be sputtered in a few hours during the trial period of the panel.
Preferably, a nickel layer or al ~Lnium layer with a thic~ness of 1 to 20 /um is used. This layer is sufficiently dense to prevent the formation of chrcmium oxide. During assembly of the panel the nickel layer or -aluminium layer o~idizes superficially but nickel oxide ~
and aluminium oxide sputter much more rapidly than - -chromium oxide. The remaining nickel or aluminium of the layer need not be removed since this does not present any difficulties for the gas discharge.
The invention will be described in greater detail with reference to the drawing, of which FigL~e 1 is a perspective sectional view of a ~
gas disch~rge display panel, embodying the invention, and i Fig~lre 2 is a sectional view on an enlarged scale of a cathode of ~he panel shown in Figure 1.
Reference numeral 1 in the drawing denotes a base plate and 2 is a top plate consisting of a trans~
' -- 3 - ~ ~
P~. 7045.
7~ ' parent insulating material, in this case glass.
Sealed in the top plate 2 are bar-shaped con-ductors 3 which serve as anodes and which are partly etched away so that channels 6 are formed. The same is the case with the conductors 4 which serve as the cathodes and are sealed in the base plate 1 which consists of glass.
The conductors 3 and 4 consist of an alloy composition of 47.5 weight percent Ni, 47.5 weight percent Fe and 5 weight percent Cr. Since the channels 6' of the base plate and the channels 6 of the top plate cross each other at right angles, cavities of which the height is equal to the sum of --the dep*hs of tWD channels 6 and 6' are formed at the cross- -ings. In said cavities gas discharges may occur by applying suitable potential differences between the crossing anodes 3 and cathodes 4.
m e plates 1 and 2 are secured together b~ means of a readily melting type of glass 8 generally denoted by the te~m "sealing glass".
It has been found that the chromium of the active ' surfaces of the conductors 3 and 4 oxidizes during sealing said conduc~ors in the plates 1 and 2 and during heating of the panel to melt the sealing glass 8, as a result of which a trial test of approximately 30 hours normally has to be carried out after filling the cavities with a suitable gas so as to sputter the chrcmium oxide from the active parts of the cathodes 4 and to obtain constant ignition and operating voltages.
, . ~.. . ~ , . .
PHN. 7045- ~ -~O~ 66 }
According to the invention this is avoided by covering the active surfaces of the cathodes 4, prior to assembly ~f the'panel, with a layer 5 of a metal which oxidizes less rapidly than chromium, or of which the oxide, possibly formed during the melting of the sealing glass, sputters more rapidly than chr~mium oxide. The ~ ' layer 5 must be sufficiently dense to prevent the fo~ma-tion of chromium oxide. However, such a layer 5 should ''~
not be provided on the cathode surfaces which constitute -' the vacuumrtight leadthrGugh of the cathode conductors to the exterior, since a chromium oxide layer promotes the adhesion to the sealing glass. `-A suitable metal is platinum which forms a suffi-cient~y dense layer of a thickness of 0.04 /um to prevent ~ ;
the formation of chromium oxide. After assembly of the panel, the thin platinum layer may be sputtered off in a ~
trial test of a few hours.0wing to the small quantity of '; ;
platinum no difficulties'occur as a result of condensa- ~' tion thereof on the walls of the channels 6 and 6'. '' An even more suitable metal for the'layer 5 is nickel. Although nickel oxidizes superficially upon l' meltin~ the sealing glass 8, said nickel oxide sputters s much more rapidly than~u~#~ chromium oxide. H~wever, ~`;' the nickel layer should bave a mLnimum thickness of 1 to 2 ' /um so as to be suffici~ntly dense, but this is no draw~
back since nickel does not exert a detrimental influence on the gas disch æ ge being itself a suit~ble electrcde `
~. ' 5 ~
', . .
PHN. 7045.
,, , ~
material. So the layer itself need not be sputtered off entirely and may therefore be chosen to be much thicker, for example 20 /um thick. Only the thin surface layer of nickel oxide should be rem~ved from the active cathode surfaces.
Alumunium is also suitable for a layer thickness of 1 to 20 /um. Although this metal also oxidizes during ~-heating ~he panel upon asse~bly,said A1203 layer may be sputtered rapidly, while the remaining aluminium layer ~;
constitutes a suitable cathode sur~ace.
Although several other metals are useful, for :, , , exa~ple, gold and silver, these metals are less suitable ~-than platinum, nickel or aluminium since ~hey have not `;
: :.., only to be provided in thicker layers than aluminium but m~reover thèy have to be sputtered off entirely because they influence the gas discharge. Detrimental dep3sits ~-. . .
may occur on ~he insulating surfaces ketween th conduc ;;
tors so that leakage current can occur and the top plate can beoome opaque.
~,
Claims (4)
1. In the method of manufacturing a gas discharge display panel comprising an insulating base plate and an insulating transparent top plate, said plates supporting electrodes consisting of a chromium alloy, which elec-trodes constitute the cathodes and anodes for the gas discharges and which plates are assembled, while being heated to form a panel, the improvement comprising cover-ing at least the parts of the cathodes operative for the gas discharges prior to assembling the panel with a layer of a metal selected from the group consisting of nickel, platinum and aluminium, said metal layer having a thick-ness sufficient to prevent the formation of chromium oxide during heating of the plates upon assembly of the panel.
2. A method as claimed in Claim 1, wherein at least the parts of the cathodes operative for the gas dis-charges are covered with a layer consisting of platinum with a thickness of about 0.04 µm.
3. A method as claimed in Claim 1, wherein at least the parts of the cathodes operative for the gas dis-charges are covered with a layer consisting of nickel with a thickness of 1 to 20 µm.
4. A method as claimed in Claim 1, wherein at least the parts of the cathodes operative for the gas discharges are covered with an aluminium layer with a thickness of 1 to 20 µm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA208,548A CA1041766A (en) | 1974-09-05 | 1974-09-05 | Forming metal coating on parts of operative cathodes in gas discharge panel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA208,548A CA1041766A (en) | 1974-09-05 | 1974-09-05 | Forming metal coating on parts of operative cathodes in gas discharge panel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1041766A true CA1041766A (en) | 1978-11-07 |
Family
ID=4101057
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA208,548A Expired CA1041766A (en) | 1974-09-05 | 1974-09-05 | Forming metal coating on parts of operative cathodes in gas discharge panel |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1041766A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107504989A (en) * | 2017-08-16 | 2017-12-22 | 钟祥市中原电子有限责任公司 | A kind of molten steel Determining oxygen probe |
-
1974
- 1974-09-05 CA CA208,548A patent/CA1041766A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107504989A (en) * | 2017-08-16 | 2017-12-22 | 钟祥市中原电子有限责任公司 | A kind of molten steel Determining oxygen probe |
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