CA1069308A - Method of manufacturing a gas discharge lamp display panel and gas discharge display panel manufactured according to said method - Google Patents
Method of manufacturing a gas discharge lamp display panel and gas discharge display panel manufactured according to said methodInfo
- Publication number
- CA1069308A CA1069308A CA264,082A CA264082A CA1069308A CA 1069308 A CA1069308 A CA 1069308A CA 264082 A CA264082 A CA 264082A CA 1069308 A CA1069308 A CA 1069308A
- Authority
- CA
- Canada
- Prior art keywords
- plate
- shaped
- glass element
- panel
- shaped glass
- 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
- 238000000034 method Methods 0.000 title claims description 14
- 238000004519 manufacturing process Methods 0.000 title claims description 10
- 239000011521 glass Substances 0.000 claims abstract description 33
- 230000005489 elastic deformation Effects 0.000 claims abstract description 7
- 239000003566 sealing material Substances 0.000 claims description 11
- 238000007789 sealing Methods 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims 5
- 229910052729 chemical element Inorganic materials 0.000 claims 1
- 239000007789 gas Substances 0.000 description 15
- 239000000725 suspension Substances 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 3
- 229910052753 mercury Inorganic materials 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000005030 aluminium foil Substances 0.000 description 2
- 229940072049 amyl acetate Drugs 0.000 description 2
- PGMYKACGEOXYJE-UHFFFAOYSA-N anhydrous amyl acetate Natural products CCCCCOC(C)=O PGMYKACGEOXYJE-UHFFFAOYSA-N 0.000 description 2
- 238000004031 devitrification Methods 0.000 description 2
- MNWFXJYAOYHMED-UHFFFAOYSA-M heptanoate Chemical compound CCCCCCC([O-])=O MNWFXJYAOYHMED-UHFFFAOYSA-M 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000000020 Nitrocellulose Substances 0.000 description 1
- 235000018734 Sambucus australis Nutrition 0.000 description 1
- 244000180577 Sambucus australis Species 0.000 description 1
- FJWGYAHXMCUOOM-QHOUIDNNSA-N [(2s,3r,4s,5r,6r)-2-[(2r,3r,4s,5r,6s)-4,5-dinitrooxy-2-(nitrooxymethyl)-6-[(2r,3r,4s,5r,6s)-4,5,6-trinitrooxy-2-(nitrooxymethyl)oxan-3-yl]oxyoxan-3-yl]oxy-3,5-dinitrooxy-6-(nitrooxymethyl)oxan-4-yl] nitrate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](O[N+]([O-])=O)[C@H]1O[N+]([O-])=O)O[C@H]1[C@@H]([C@@H](O[N+]([O-])=O)[C@H](O[N+]([O-])=O)[C@@H](CO[N+]([O-])=O)O1)O[N+]([O-])=O)CO[N+](=O)[O-])[C@@H]1[C@@H](CO[N+]([O-])=O)O[C@@H](O[N+]([O-])=O)[C@H](O[N+]([O-])=O)[C@H]1O[N+]([O-])=O FJWGYAHXMCUOOM-QHOUIDNNSA-N 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 239000005357 flat glass Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910052754 neon Inorganic materials 0.000 description 1
- GKAOGPIIYCISHV-UHFFFAOYSA-N neon atom Chemical compound [Ne] GKAOGPIIYCISHV-UHFFFAOYSA-N 0.000 description 1
- 229920001220 nitrocellulos Polymers 0.000 description 1
- 229940079938 nitrocellulose Drugs 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
- H01J9/24—Manufacture or joining of vessels, leading-in conductors or bases
- H01J9/26—Sealing together parts of vessels
- H01J9/261—Sealing together parts of vessels the vessel being for a flat panel display
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
- Joining Of Glass To Other Materials (AREA)
Abstract
ABSTRACT:
In gas discharge display panels of some dimension a fracture in the seal between the plate-shaped elements of the panel is obtained in many cases upon evacuating the panel. Said fracture is a result of the fact that the plate-shaped elements, for example the glass face plate of the panel, are not entirely flat so that said elements contact the intermediately located spacing members in an insufficient number of places. This problem is solved by producing the vacuum-tight seal between the plate-shaped elements while maintaining such a pressure on the surface of said element that they are brought in permanent contact with the spacing members. Furthermore, at least the glass face plate is preferably heated to such a high temperature that a possible elastic deformation of said element resulting from a pressure exerted on the surface thereof is converted into a plastic deformation.
In gas discharge display panels of some dimension a fracture in the seal between the plate-shaped elements of the panel is obtained in many cases upon evacuating the panel. Said fracture is a result of the fact that the plate-shaped elements, for example the glass face plate of the panel, are not entirely flat so that said elements contact the intermediately located spacing members in an insufficient number of places. This problem is solved by producing the vacuum-tight seal between the plate-shaped elements while maintaining such a pressure on the surface of said element that they are brought in permanent contact with the spacing members. Furthermore, at least the glass face plate is preferably heated to such a high temperature that a possible elastic deformation of said element resulting from a pressure exerted on the surface thereof is converted into a plastic deformation.
Description
The invention relates to a method of manufac-turing a gas discharge display panel in which a first plate-shaped glass element is sealed in a vacuum-tight manner to a second plate-shaped element only along a closed path, a defined space being maintained between said elements by means of at least one spacing member situated inside the closed path.
The invention furthermore relates to a gas discharge display panel manufactured according to the method.
The development of gas discharge panels for displaying information in the form of digits, letters and television pictures has of late been directed mainly to the manufacture of panels which, as regards picture size, can compare with that of the preset-day cathode ray tubes. It has been found that certain methods which are usual in the manufacture of small panels, that is to say panels smaller than 10 x lO cm, cannot be used as such in manufacturing panels of larger dimensions. Problems occur notably when in one of the last phases of the manufacturing process a negative pressure with respect to the ambient pressure outside the panel is provided in the panel and the space between the plate-shaped elements is filled with a suitable ionisable gas. As a result of said negative
The invention furthermore relates to a gas discharge display panel manufactured according to the method.
The development of gas discharge panels for displaying information in the form of digits, letters and television pictures has of late been directed mainly to the manufacture of panels which, as regards picture size, can compare with that of the preset-day cathode ray tubes. It has been found that certain methods which are usual in the manufacture of small panels, that is to say panels smaller than 10 x lO cm, cannot be used as such in manufacturing panels of larger dimensions. Problems occur notably when in one of the last phases of the manufacturing process a negative pressure with respect to the ambient pressure outside the panel is provided in the panel and the space between the plate-shaped elements is filled with a suitable ionisable gas. As a result of said negative
- 2 - ~
~ O 6 9 3 O 8 PHN 8208 pressure there is a r{sk o~ a fracture occurring in the seal joining the plate-shaped elements so that the panel is useless.
Investigations have proved that the cause of said fracture is mainly a result of the fact that the plate-shaped elements, such as a glass plate, are not entirely fla'c. Deviations of 250/um are no exception.
It may occur that one or both plate-shaped elements are not supported by a spacing member over too large a surface.
As a result of this, during providing a nega~ive pressure in the panel, at least one of said plate-shaped elements sags so that the connection seam between said elements is loaded too heavily.
A considerable improvement in this respect lS would be obtained if in assembling the panel the starting material were entirely flat plate-shaped elements. How-ever, such a solution is not attractive economically because for that purpose the elements would have to be subjected to an extra and usually expensive treatment.
It is an object of the invention to provide a method of manufacturing a gas discharge display panel in which the occurrence of fracture as a result of negative pressure in the panel is avoided.
According to the invention, a method of the kind mentioned in the preamble is characterized in that the vacuum-tight seal between the elements is effected while maintaining such a pressure on the surface of the plate-shaped elements that said elements are brought into permanent contact with the said spacing member.
~069308 When the plate-shaped elements have been brought into contact with the spacing member and in that state the final sealing of the panel is effected, the load on the seal between the elements tends to remain more constant during later stages of manufacture. According to the invention, such a contact can be realised in a simple manner when a pressure which is at least equal to the pressure which was necessary to contact the elements with the said spacing member is maintained on the surface of the plate-shaped elements from the point in the process at which these elements are sealed together up to and including the sealing of the exhaust tube of the gas discharge display panel.
Such a contact is preferably effected by providing in the said space between the elements a negative pressure with respect to the amb;ent pressure of the panel.
Suitably at least the said first plate-shaped glass element is furthermore heated to such a high temperature below the softening temperature of the glass from which it is manu-factured that a possible elastic-deformation of said element, obtained by a pressure exerted on the surface thereof, is converted into a plastic deformation. Softening temperature is to be understood to mean herein that temperature at which the glass just does not deform under its own weight. The advantage of this embodiment of the method according to the invention is that immediately after producing the vacuum-tight connection between the elements, the negative pressure in the panel can be removed without any objection.
.
. . . . .
The panel may then be filled with a suitable ionisable gas to any desired pressure smaller than or equal to the atmospheric pressure.
For converting a possible elastic deformation into a plastic deformation it is not necessary to heat the glass plate or plates up to softening temperature as defined above. Already at a considerably lower temperature than the softening temperature meant here can the object of the invention be realised. A suitable choice of this temperature is determined in general by the type of sealing and the type of sealing material which is used to seal the plate-shaped elements together. Furthermore, the choice of temperature is associated with the way in which the temperature can best be fitted in the manufacturing process, while the construction of the panel itself with respect to such a choice may also play an important part.
According to the invention, preferably at least the first plate-shaped glass element is heated to a temperature which is approximately equal to the lowest strain point of the glass (from which it is manufactured), that is that ~emperature at which the glass has a viscosity of 1014-5 poises. In this connection "approxi-mately" is to be understood to mean a spreading of 30C
relative to the lowest strain point. It has been found, rather surprisingly, that even at temperatures below the lowest strain point an elastic deformation of the glass plate can be converted into a permanent deformation within a reasonable time. This time becomes the shorter as the temperature is higher.
^ 5 -The advantage of the invention is that a thin glass plate of normal window glass may be used even for large panels.
The invention will be described in greater detail with reference to the drawing, in which:
Figure 1 shows a gas discharge display panel partly broken away, and Figure 2 shows a phase in an embodiment of the method according to the invention.
The gas discharge panel shown in Figure 1 comprises a first plate-shaped element 1 consisting of a 4 mm thick glass face plate of 32 x 32 cm. A second plate-shaped element
~ O 6 9 3 O 8 PHN 8208 pressure there is a r{sk o~ a fracture occurring in the seal joining the plate-shaped elements so that the panel is useless.
Investigations have proved that the cause of said fracture is mainly a result of the fact that the plate-shaped elements, such as a glass plate, are not entirely fla'c. Deviations of 250/um are no exception.
It may occur that one or both plate-shaped elements are not supported by a spacing member over too large a surface.
As a result of this, during providing a nega~ive pressure in the panel, at least one of said plate-shaped elements sags so that the connection seam between said elements is loaded too heavily.
A considerable improvement in this respect lS would be obtained if in assembling the panel the starting material were entirely flat plate-shaped elements. How-ever, such a solution is not attractive economically because for that purpose the elements would have to be subjected to an extra and usually expensive treatment.
It is an object of the invention to provide a method of manufacturing a gas discharge display panel in which the occurrence of fracture as a result of negative pressure in the panel is avoided.
According to the invention, a method of the kind mentioned in the preamble is characterized in that the vacuum-tight seal between the elements is effected while maintaining such a pressure on the surface of the plate-shaped elements that said elements are brought into permanent contact with the said spacing member.
~069308 When the plate-shaped elements have been brought into contact with the spacing member and in that state the final sealing of the panel is effected, the load on the seal between the elements tends to remain more constant during later stages of manufacture. According to the invention, such a contact can be realised in a simple manner when a pressure which is at least equal to the pressure which was necessary to contact the elements with the said spacing member is maintained on the surface of the plate-shaped elements from the point in the process at which these elements are sealed together up to and including the sealing of the exhaust tube of the gas discharge display panel.
Such a contact is preferably effected by providing in the said space between the elements a negative pressure with respect to the amb;ent pressure of the panel.
Suitably at least the said first plate-shaped glass element is furthermore heated to such a high temperature below the softening temperature of the glass from which it is manu-factured that a possible elastic-deformation of said element, obtained by a pressure exerted on the surface thereof, is converted into a plastic deformation. Softening temperature is to be understood to mean herein that temperature at which the glass just does not deform under its own weight. The advantage of this embodiment of the method according to the invention is that immediately after producing the vacuum-tight connection between the elements, the negative pressure in the panel can be removed without any objection.
.
. . . . .
The panel may then be filled with a suitable ionisable gas to any desired pressure smaller than or equal to the atmospheric pressure.
For converting a possible elastic deformation into a plastic deformation it is not necessary to heat the glass plate or plates up to softening temperature as defined above. Already at a considerably lower temperature than the softening temperature meant here can the object of the invention be realised. A suitable choice of this temperature is determined in general by the type of sealing and the type of sealing material which is used to seal the plate-shaped elements together. Furthermore, the choice of temperature is associated with the way in which the temperature can best be fitted in the manufacturing process, while the construction of the panel itself with respect to such a choice may also play an important part.
According to the invention, preferably at least the first plate-shaped glass element is heated to a temperature which is approximately equal to the lowest strain point of the glass (from which it is manufactured), that is that ~emperature at which the glass has a viscosity of 1014-5 poises. In this connection "approxi-mately" is to be understood to mean a spreading of 30C
relative to the lowest strain point. It has been found, rather surprisingly, that even at temperatures below the lowest strain point an elastic deformation of the glass plate can be converted into a permanent deformation within a reasonable time. This time becomes the shorter as the temperature is higher.
^ 5 -The advantage of the invention is that a thin glass plate of normal window glass may be used even for large panels.
The invention will be described in greater detail with reference to the drawing, in which:
Figure 1 shows a gas discharge display panel partly broken away, and Figure 2 shows a phase in an embodiment of the method according to the invention.
The gas discharge panel shown in Figure 1 comprises a first plate-shaped element 1 consisting of a 4 mm thick glass face plate of 32 x 32 cm. A second plate-shaped element
3 consisting of a 4 mm thick glass rear plate is maintained at a defined distance from the plate 1 by means of a spacing member 2, consisting of a 0.3 mm thick intermediate plate of anodised aluminium. The face plate 1 and the rear plate 3 consist of glass having substantially the following composition:
69.1% by weight of SiO2, 9% by weight of Na20, 7.4% by weight of K20, 9.7% by weight of CaO, 2.8% by weight of BaO. This ~o glass has a lowest strain point of 505C (viscosity 1014-5 poises). In a modification the rear plate need not consist of glass but may be any insulating material which is suitable for this application, for example ceramic. Furthermore, the spacing member 2 need not consist of one plate but separate spacing members distributed over the surface of the face plate may alternatively be used. The gas discharge panel illustrated has a first set of electrodes 4 disposed between the rear plate 3 and the intermediate plate 2, and a second set of electrodes 5 disposed between the face plate 1 and the intermediate plate 2. Each electrode 4 crosses each electrode 5 and at the area of such a crossing there is a perforation 8 in the intermediate plate 2. In this manner each crossing defines a gas discharge cell and all the crossings together constitute a matrix of gas dis-charge cells each of which can be ignited selectively by applying a suitable potential difference between an electrode 4 and an electrode 5. If desired, grooves may be provided in the face plate and the rear plate respectively, in which the electrodes 4 and 5, are located. By choosing the depth of said grooves to be such as to determine the required dis-tance between the electrodes 4 and the electrodes 5, the intermediate plate 2 may be omitted and the ridges between the grooves constitute the spacing members as referred to above.
After assembling the parts as shown in the drawing, which may be carried out in a jig, the face plate 1 and the rear plate 3 are connected together in a vacuum-tight manner along a closed path only, in this case along the edge of the rear plate, by means of a sealing material 6. The sealing material is a crystallizing (devitrifying) glass and is applied in the form of a suspension of glass powder in a solution of 1% nitro-cellulose in amyl acetate.
A viscosity of the suspension suitable for this application is obtained with a composition of 10 parts by weight of glass powder in 1 part by weight of binder.
After evaporating the amyl acetate from the .. . . . ...... .... ... . ..
; suspension, the assembly is heated in an oven to a temperature of 440C at which some devitrification of the sealing material starts to take place. The increase of viscosity of the sealing material associated with said devitrification is such as to permit a negative pressure of approximately 5 cm mercury in the panel with respect to the ambient pressure without the sealing material being sucked into the panel to an unacceptable distance.
As a result of said negative pressure, the face plate and the rear plate are deformed elastically in places where, as a result of their unsmoothness, they do not bear against the intermediate plate 2 until they contact the plate in places distributed over the surface. At this stage the sealing material 6 is still so soft that it does not prevent relative movement between the plates. The temperature is now raised to 485C and maintained there for 30 minutes, the elastic deformation of the plates being converted into a permanent deformation and the sealing material being converted at least partly into a crystalline phase. The panel is finally cooled after which the space in the panel is filled with an ionisable gas, such as for example, neon, argon, xenon, and the exhaust tube 7 is sealed.
The above-described method is only one of the many possibilities. The procedure described may be altered in a number of ways. For example, it is possible to maintain in the panel the negative pressure of 5 cm mercury for a restricted period of time~ for example, 10 minutes, and to increase said negative pressure to, ~069308 ` PHN 8208 for example, 40 cm mercury with the raising of the temper-ature to 485C. The advantage of this larger negative pressure is that the electrodes are subject to oxidation to a smaller extent and a possible oxide skin is rapidly sputtered away from the cathodes during the initial operation of the panel.
Figure 2 shows diagrammatically in what manner the object according to the invention can be achieved other than by means of a negative pressure in the panel. The envelope of the panel again consists of two plates 10 and 11 which are sealed together only along the edge of the glass plate 10 by means of a suspension of a devitrifiable glass 12. The assembly is accommodated in a metal housing 14 which can be closed in a vacuum-tight manner by means of a cover 13, the exhaust tube 15 of the panel being inserted through an aperture in the base plate of the housing 14. The exhaust tube 15 communicates with an exhaust duct 16 having a cock 17, the aperture in the base plate of the housing 14 being sealed hermetically from the atmosphere by means of a bellows seal 23. The exhaust duct 16 communicates at one end with a seco~d exhaust duct 18, which communicates with the space sur-rounded by the housing 14 and which has two cocks 19 and 20. The cover 13 consists of an aluminium foil 21 having expansion bellows 22. With the cocks 17, 19 and 20 in the opened position, the interior of the housing 14 and the gas discharge panel accommodated therein is evacuated by means of a pumping set not shown. The ambient pressure ~L~69308 PHN 8208 transferred to the plate 10 via the aluminium foil 21 presses the plates 10 and 11 towards each other until they come into contact with the spacing members 24 between the plates. By means of an analogous tempera-ture treatment as described with reference to figure 1, the elastic deformation of the plates 10 and 11 is again converted into a plastic deformation, the con-nection material 12 being devitrified. After cooling the assembly, the cock 17 is closed and air is admitted to the housing 14 via the duct 18, after which the cover 13 is removed. The cock 20 is then closed and the duct 18 evacuated. The cock 17 is finally opened i again and the panel is filled with a suitable ionisable 9 gas via the ducts 18 and 16, after which the exhaust ~, 15 tube 15 is sealed and the pane1 is taken out of the ; housing 14 ready for operation.
Although the invention has been explained wit~ reference to examples in which the sealing material t:, `, ` consists of a devitrifiable glass, it is by no means restricted thereto. Other sealing or connection material and even other connection methods may be used without departing from the sco~e of this invention.
. .
:`
- lQ -. , ,. . ....... .. ...
69.1% by weight of SiO2, 9% by weight of Na20, 7.4% by weight of K20, 9.7% by weight of CaO, 2.8% by weight of BaO. This ~o glass has a lowest strain point of 505C (viscosity 1014-5 poises). In a modification the rear plate need not consist of glass but may be any insulating material which is suitable for this application, for example ceramic. Furthermore, the spacing member 2 need not consist of one plate but separate spacing members distributed over the surface of the face plate may alternatively be used. The gas discharge panel illustrated has a first set of electrodes 4 disposed between the rear plate 3 and the intermediate plate 2, and a second set of electrodes 5 disposed between the face plate 1 and the intermediate plate 2. Each electrode 4 crosses each electrode 5 and at the area of such a crossing there is a perforation 8 in the intermediate plate 2. In this manner each crossing defines a gas discharge cell and all the crossings together constitute a matrix of gas dis-charge cells each of which can be ignited selectively by applying a suitable potential difference between an electrode 4 and an electrode 5. If desired, grooves may be provided in the face plate and the rear plate respectively, in which the electrodes 4 and 5, are located. By choosing the depth of said grooves to be such as to determine the required dis-tance between the electrodes 4 and the electrodes 5, the intermediate plate 2 may be omitted and the ridges between the grooves constitute the spacing members as referred to above.
After assembling the parts as shown in the drawing, which may be carried out in a jig, the face plate 1 and the rear plate 3 are connected together in a vacuum-tight manner along a closed path only, in this case along the edge of the rear plate, by means of a sealing material 6. The sealing material is a crystallizing (devitrifying) glass and is applied in the form of a suspension of glass powder in a solution of 1% nitro-cellulose in amyl acetate.
A viscosity of the suspension suitable for this application is obtained with a composition of 10 parts by weight of glass powder in 1 part by weight of binder.
After evaporating the amyl acetate from the .. . . . ...... .... ... . ..
; suspension, the assembly is heated in an oven to a temperature of 440C at which some devitrification of the sealing material starts to take place. The increase of viscosity of the sealing material associated with said devitrification is such as to permit a negative pressure of approximately 5 cm mercury in the panel with respect to the ambient pressure without the sealing material being sucked into the panel to an unacceptable distance.
As a result of said negative pressure, the face plate and the rear plate are deformed elastically in places where, as a result of their unsmoothness, they do not bear against the intermediate plate 2 until they contact the plate in places distributed over the surface. At this stage the sealing material 6 is still so soft that it does not prevent relative movement between the plates. The temperature is now raised to 485C and maintained there for 30 minutes, the elastic deformation of the plates being converted into a permanent deformation and the sealing material being converted at least partly into a crystalline phase. The panel is finally cooled after which the space in the panel is filled with an ionisable gas, such as for example, neon, argon, xenon, and the exhaust tube 7 is sealed.
The above-described method is only one of the many possibilities. The procedure described may be altered in a number of ways. For example, it is possible to maintain in the panel the negative pressure of 5 cm mercury for a restricted period of time~ for example, 10 minutes, and to increase said negative pressure to, ~069308 ` PHN 8208 for example, 40 cm mercury with the raising of the temper-ature to 485C. The advantage of this larger negative pressure is that the electrodes are subject to oxidation to a smaller extent and a possible oxide skin is rapidly sputtered away from the cathodes during the initial operation of the panel.
Figure 2 shows diagrammatically in what manner the object according to the invention can be achieved other than by means of a negative pressure in the panel. The envelope of the panel again consists of two plates 10 and 11 which are sealed together only along the edge of the glass plate 10 by means of a suspension of a devitrifiable glass 12. The assembly is accommodated in a metal housing 14 which can be closed in a vacuum-tight manner by means of a cover 13, the exhaust tube 15 of the panel being inserted through an aperture in the base plate of the housing 14. The exhaust tube 15 communicates with an exhaust duct 16 having a cock 17, the aperture in the base plate of the housing 14 being sealed hermetically from the atmosphere by means of a bellows seal 23. The exhaust duct 16 communicates at one end with a seco~d exhaust duct 18, which communicates with the space sur-rounded by the housing 14 and which has two cocks 19 and 20. The cover 13 consists of an aluminium foil 21 having expansion bellows 22. With the cocks 17, 19 and 20 in the opened position, the interior of the housing 14 and the gas discharge panel accommodated therein is evacuated by means of a pumping set not shown. The ambient pressure ~L~69308 PHN 8208 transferred to the plate 10 via the aluminium foil 21 presses the plates 10 and 11 towards each other until they come into contact with the spacing members 24 between the plates. By means of an analogous tempera-ture treatment as described with reference to figure 1, the elastic deformation of the plates 10 and 11 is again converted into a plastic deformation, the con-nection material 12 being devitrified. After cooling the assembly, the cock 17 is closed and air is admitted to the housing 14 via the duct 18, after which the cover 13 is removed. The cock 20 is then closed and the duct 18 evacuated. The cock 17 is finally opened i again and the panel is filled with a suitable ionisable 9 gas via the ducts 18 and 16, after which the exhaust ~, 15 tube 15 is sealed and the pane1 is taken out of the ; housing 14 ready for operation.
Although the invention has been explained wit~ reference to examples in which the sealing material t:, `, ` consists of a devitrifiable glass, it is by no means restricted thereto. Other sealing or connection material and even other connection methods may be used without departing from the sco~e of this invention.
. .
:`
- lQ -. , ,. . ....... .. ...
Claims (4)
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PRO-PERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Method of manufacturing a gas discharge display panel comprising a first plate-shaped glass element, a second plate-shaped element, a spacing member intermediate said plate-shaped elements and a tubulation for exhausting and backfilling said panel, the method comprising the steps of assembling said plate-shaped elements and said intermediate spacing member, placing a heat fusible sealing material in contact with said plate-shaped elements along a closed path surrounding said spacing member, exerting a uniform pressure on the entire surface of at least the plate-shaped glass ele-ment sufficient to elastically deform said plate-shaped glass element and to bring it into contact with the spacing member, heating the assembly to a temperature above the softening point of said sealing material but below the softening point of said plate-shaped glass element for a sufficient time to thereby form a vacuum-tight seal between the plate-shaped elements and convert the elastic deformation of said plate-shaped glass element obtained by the uniform pressure exerted on the surface thereof into a permanent deformation, evacua-ting and backfilling the space between said plate-shaped elements with an ionizable gas through said tubulation and sealing said tubulation.
2. Method of claim 1 wherein the step of exerting the uniform pressure on the surface of the plate-shaped glass element comprises reducing the pressure in the space between the plate-shaped elements during sealing to effec-PHN.8208.
tively maintain external pressure on said plate-shaped glass element.
tively maintain external pressure on said plate-shaped glass element.
3. Method of claim 1 wherein the heating step com-prises heating the assembly to a temperature which is approximately equal to the temperature at the lowest strain point of the plate-shaped glass element.
4. Method of claim 2 wherein the heating step com-prises heating the assembly to a temperature which is approximately equal to the temperature at the lowest strain point of the plate-shaped glass element.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL7512517A NL7512517A (en) | 1975-10-27 | 1975-10-27 | METHOD OF MANUFACTURING A GAS DISCHARGE DISPLAY PANEL AND GAS DISCHARGE DISPLAY PANEL THEREFORE MANUFACTURED. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1069308A true CA1069308A (en) | 1980-01-08 |
Family
ID=19824736
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA264,082A Expired CA1069308A (en) | 1975-10-27 | 1976-10-25 | Method of manufacturing a gas discharge lamp display panel and gas discharge display panel manufactured according to said method |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5836804B2 (en) |
| CA (1) | CA1069308A (en) |
| DE (1) | DE2647552A1 (en) |
| FR (1) | FR2330136A1 (en) |
| GB (1) | GB1559869A (en) |
| NL (1) | NL7512517A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3328036A1 (en) * | 1983-08-03 | 1985-02-14 | Siemens AG, 1000 Berlin und 8000 München | GAS DISCHARGE DISPLAY DEVICE WITH A SPACER FRAME AND METHOD FOR PRODUCING THIS FRAME |
| JPS60227336A (en) * | 1984-04-25 | 1985-11-12 | Toshiba Corp | Lead frame material for diaplay tube |
| JPS60258825A (en) * | 1984-06-05 | 1985-12-20 | Fujitsu Ltd | Manufacture of gas discharge display panel |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1340007A (en) * | 1971-12-02 | 1973-12-05 | Standard Telephones Cables Ltd | Gas discharge display matrix |
-
1975
- 1975-10-27 NL NL7512517A patent/NL7512517A/en not_active Application Discontinuation
-
1976
- 1976-10-21 DE DE19762647552 patent/DE2647552A1/en not_active Ceased
- 1976-10-22 GB GB4394476A patent/GB1559869A/en not_active Expired
- 1976-10-23 JP JP12681876A patent/JPS5836804B2/en not_active Expired
- 1976-10-25 CA CA264,082A patent/CA1069308A/en not_active Expired
- 1976-10-27 FR FR7632344A patent/FR2330136A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5254368A (en) | 1977-05-02 |
| GB1559869A (en) | 1980-01-30 |
| FR2330136B1 (en) | 1982-01-08 |
| DE2647552A1 (en) | 1977-04-28 |
| FR2330136A1 (en) | 1977-05-27 |
| NL7512517A (en) | 1977-04-29 |
| JPS5836804B2 (en) | 1983-08-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4139250A (en) | Gas discharge display panel and method of manufacturing the same | |
| US5897927A (en) | Seal for vacuum devices and methods for making same | |
| US6194830B1 (en) | Multi-compartment getter-containing flat-panel device | |
| JP2000172202A (en) | Flat panel image display device and method of manufacturing the same | |
| CA1069308A (en) | Method of manufacturing a gas discharge lamp display panel and gas discharge display panel manufactured according to said method | |
| US4666548A (en) | Process for making fluorescent display device | |
| US3931436A (en) | Segmented gas discharge display panel device and method of manufacturing same | |
| EP0958589B1 (en) | Local energy activation of getter | |
| EP0042003B1 (en) | Method for forming a fusible spacer for plasma display panel | |
| US6459198B1 (en) | Seal and method of sealing devices such as displays | |
| US4428764A (en) | Method of making fusible spacer for display panel | |
| JPS6316543A (en) | Flash discharge tube | |
| US6257945B1 (en) | Method for sealing a gas within a picture display device | |
| US3944868A (en) | Segmented gas discharge display panel device | |
| US4009407A (en) | Segmented electrode type gas discharge display panel with mercury giver means | |
| US4119378A (en) | Segmented gas discharge display panel device and method of manufacturing same | |
| JPH06302279A (en) | Flat display panel | |
| JP2001313343A (en) | Airtight container and its manufacturing method | |
| CN101027746A (en) | Lighting device component assembly with solder glass preform and sealing process | |
| US4051404A (en) | Gas discharge display panel with fused sealing plug | |
| US4105889A (en) | Laser method of introducing mercury to gas discharge display panels | |
| WO2008025998A2 (en) | Glass structures | |
| JPS6326924A (en) | Flat discharge tube and its manufacture | |
| JPH10223143A (en) | Planar light emitting device | |
| JPH0311524A (en) | Method for vacuum-hermetic sealing fluorescent character display tube |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |