CA1136202A - Method of sealing a gas discharge display without a tubulation - Google Patents
Method of sealing a gas discharge display without a tubulationInfo
- Publication number
- CA1136202A CA1136202A CA000328225A CA328225A CA1136202A CA 1136202 A CA1136202 A CA 1136202A CA 000328225 A CA000328225 A CA 000328225A CA 328225 A CA328225 A CA 328225A CA 1136202 A CA1136202 A CA 1136202A
- Authority
- CA
- Canada
- Prior art keywords
- plates
- gas
- envelope
- frit material
- display device
- 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
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
Abstract
Abstract A method for constructing a gas discharge display with-out the utilization of an exterior exhaust tubulation structure.
When the face plate and base plate of the display device are as-sembled in face-to-face relation, irregularities in the sealing frit material provide vias to the interior envelope of the gas display device to allow evacuation of the envelope and the intro-duction of the ionized gas. The frit material is preglazed to ensure a hermetic seal between the plates when the frit is melted.
Specially designed biasing means are attached to the plates to provide a tighter force between the plates while the frit material is being melted and devitrified to seal the interior envelope containing the ionizable gas.
When the face plate and base plate of the display device are as-sembled in face-to-face relation, irregularities in the sealing frit material provide vias to the interior envelope of the gas display device to allow evacuation of the envelope and the intro-duction of the ionized gas. The frit material is preglazed to ensure a hermetic seal between the plates when the frit is melted.
Specially designed biasing means are attached to the plates to provide a tighter force between the plates while the frit material is being melted and devitrified to seal the interior envelope containing the ionizable gas.
Description
Background of thc Invention The present invention is directed to making a gas dis-charge display device without an external -tubulation and more particularly is directed to a method of making a gas display device having no tubulation in a more efEicient manner and wi-th an improved seal.
The commonly used method for constructing a gas dis-charge display device incorporates the use of a tubulation port in one of the pla-tes that forms -the display device. A rather fragile tubulation glass chalmel extends away from the display plate adjacent the tubulation port -to provide a channel for the evacuation of the envelope in the display device and for the subsequent in-troduction of an ionizable gas. Once the display is filled with an ionizable gas at the proper pressure, the tubula-tion member is pinched off to seal the display. However, asignificant portion of the tubulation member remains attached to the display device presenting a projection exterior to the dis-play device essen-tially perpendicular to the plane of the display device. Being nlade of glass material, the projecting tubulation `' ' - ' ~.
! r .
' '' ., ' :~i '. . ~ ' ' .
?
iLJL~ ~d is extremely fragile and is susceptible to breakage during packing, trans-porting or use of the display device. Consequently, many displays must be repaired or scrapped when breakage of the tubulation occurs.
! Because of the utilization of a tubulation tube on a gas discharge display device presents a very fragile member in the device, various approaches have been utilized to avoid incorporating the tubulation member.
In one approach a gap is left in the sealing frit material around the perimeter of the viewing area of the display device to provide an exhaust port for evacuating the envelope and an entry port to fill the envelope with the ionizable gas. After the filling of the envelope with the ionizable gas, the gap in the sealing frit is sealed with a sealing material or lcw melting glass plug which is melted to enclose the gap. Examples of such an approach are shcwn in the Kupsky 4,009,407, Hinson 4,013,912 and Przybylek 3,980,366 patents.
Another approach has been to plug the tubulation port with some type of sealing material which is heated to enclose or plug the tubulation port leaving no tubulation extending frcm the exterior surface of the plate. An example of such arrangements are shcwn in the Beckerman et al. 3,914,000 patent and the Frankland et al,4,182,540 patent entitled MEI~iOD OF SE~LING GAS DISCHARGæ DISPLAYS.
Another approach to eliminating the utilization of a tubulation member on the gas display device i5 shcwn in the Wilson 3,778,126 patent wherein a sealing material initially has a permeable ch æ acteristic so that envelope evacuation and gas introduction can be done through the sealing material after which ~he device is heated sufficiently to melt the sealing material and seal the gas within the envelope.
Although many of the above described approaches eliminate the -utilization of a tubulation me~ber on the gas display dm~ 2 -~3~
device, each has certain relative disadvantages. The use of a separate sealing material to plug a gap in the frit of the display device requires special equipment to properly orient the sealing element as well as proper controls or even the use of special heating equipmen-t to provide the necessary heating of the sealing plug. The requirement of special equipment to heat the sealing plug is especially true with respect to the Beckerman patent which utilizes a separate small heating unit which must be placed adjacent the sealing plug to cover the exhaust port in one of the plates of the display.
In most of these approaches the sealing time for the display is considerably longer than desired and in many instances the sealing frit is not properly prepared to provide a satisfactory and reliable seal. Also, in many of the above disclosed approaches the evacuation and gas filling of the display envelope require special equipment connected to each of the display devices.
Summary of the Invention The present invention is a method for making a gas discharge display device without having a tubulation projecting from the display. Specifically, the invention relates to a method for constructing a gas display device having a face plate and a back plate forming an envelope containing display electrodes. The method comprises the steps of s_reen printing a frit material on at least one of the plates; preglazing the frit material in an atmospheric environment to remove all organic binders within the frit material; assembling the plates in face-to-face relation to ~i mb/sb - 3 -;~ :
..
:: . : , - . ~ . .
., ~ :
..
-- ~ 3~ ~d~) form the envelope; placing the plates within a vacuum furnace; evacuating the atmosphere within the envelope through the interface of the frit material and the other of the plates; introducing an ionizable gas into the envelope; andheating the frit material to hermetically seal the plates with no exhaust port in the plates and the frit material~
In its apparatus aspect the invention relates to a gas discharge display device comprising a nonapertured base plate; a nonapertured face plate positioned in face-to-face spaced relation with the base plate to form an envelope; a screen printed preglazed frit material located between the plates to form a perimeter seal around the plates to hermetically seal the plates, the frit material bein~ continuous throughout the perimeter around the plates, the frit material prior to establishing the hermetic seal providing passageways for the evacuation and backfilling of the envelope, the frit material having substantially no organic binder material when the hermetic seal is formed, means in the frit material for maintaining the space between the plates; an ionizable gas within the envelope; and electrodes within the envelope for selectively activating the gas to provide a visible message, the device having no fill ports for the introduction of the gas into the envelope.
Thus, the process of the present invention prepares :
the sealing frit in such a manner that it is preglazed to remove any organic binders from the sealing frit, so that, when it is heated for sealing between the plates of the 1- mb/~ ~ 3a -~ .
. . -, ,... ,; ~ , , , , ,.'. , ~ '`,: . ,, . : , ' :` ' ' display, a rellable and permanent seal i5 established.
Also incorporated in the present invention is the utilization of biasing means attached between the plates when they are assembled in face-to-face relation so that during the heating step to provide the seal between the plates the time required is significantly reduced and the seal is greatly improved.
The irregularities in the sealing frit prior to its heating for sealing provides the necessary passageways for the : mb/ l - 3b -. . . ~ . .: ,: .
. . . , : , -, 4~ 114 evacuation and filling of the envelope in a vacuum furnace prior to the sealing of the plates. The use of the vacuum furnace allows Eor the simultaneolls evacuation and ~illing of several display devices without the need of any special connecting equip-ment be-tween each display and a vacuum source as well as an ionizable gas source.
Conse~uently, the present invention not only eliminates the use of a tubulation in -the device, but also eliminates the requirement for a special aperture in eitller of the plates or in the sealing frit as an evacuation and gas filling port. In addition, the present invention utilizes a method -to reduce the time required during the heating cycle for sealing the plates together with the sealing frit or material. The use of the biasing means also allows for a reduction in the temperature re-quired for the proper sealing.
Without the proper preparation of the sealing frit by a preglaxing process in an air or oxygen environment -to remove -the organic binders, the frit upon melting for sealing may have a porosity which would result in a nonhermetic seal.
The present invention also u-tilizes a sealing frit ..
which is screened onto -the perimeter of one of the face plates.
The heating of the sealing frit to hermetically seal the pla-tes together results in a devi-tri:Eication of the frit.
In summary, the present invention teaches a method for making a gas display device without a tubulation member in such a manner -that not only the -time, but also -the temperature required to seal the pla-tes is reduced, and the frit is prepared in such a manner that i-t will create a reliable and hermetic sea:L between the plates which is extremely important to the gas fil].ed enve-lope of the display.
P,rief _e~c~e~ of the Dra~in~s Figure l is a pe:Lspective vi.ew of a display device :~
_~_ `, . .
` ~2~-114 ~3~
prior to assembly of the plates, showing the interior surface of each of the plates;
Figure 2 is a perspective view of the plates asiembled in a display device with biasing means attached to the plates;
Figure 3 i5 an enlarged end view with one of the bias-ing means removed showing the irregularities of the sealing frit prior to heating of -the sealing frit to sealed plates; and Figure 4 is an enlarged end view of the device similar to Figure 3 showing the sealing frit after it has been heated to create the seal be-tween the respective plates.
De-tailed Description of the Invention In Figure 1 the face plate 10 and the base pla-te 12 of a gas discharge display 14 are shown prior to assembly with the interior surfaces 16 and 13 of the respective face plate 10 and base plate 12 exposed. Located on the interior surface 18 of the base plate 12 is an electrode pattern comprised of a plurality of character positions 20 formed by a series of separate cathode electrode segments 22. A dielectric layer 24 covers the electrode conductive runs which have been screened on the base plate 12 to properly interconnect the appropriate cathode segments 22 with the terminal pads 26 located along the longitudinal edge 28 of tlle base plate 12. Both the electrode pa-ttern and the dielectric layer 24 are preferably screen printed on the interior surface 18 of the base pla-te 12.
~eposited on the interior surface 16 of the face pla-te 10 are a plurality of anode electrodes 30 which are designed to operate in conjunction with each of the character positions 20 on the base plate 12. The anodes 30 are preferably made of a trans-parent material such as tin oxide. Each of the anodes 30 is ~-connected to a respec-tive terminal pad 26 by a clip (not shown) placed between the plates. Located around -the per.~phery of the anodes 30 is a sealing frit 32. The sealing frit 32 is prefera-, .` ; ' ' . . : ,-~' , ' ' ' ' ' ' '~.J~ 3~2 ~ bly screen printed on-to the face plate. One preferable material -~i` is Corning 75~5 frit although Corning 7555 is another frit material to use. Glass beads, not shown, are in the sealing frit so that, when the frit melts, tlle glass beads will establish the necessary spacing between the plates when they are assembled. It should be noted that the cathode electrodes 22 and the anodes 30 could be placed on the base plate 12 in a coplanar relationship.
Once the cathode electrodes 22, the anode electrodes 30, the dielectric layer 24 and the sealing frit 32 have been properly placed on the respective interior surfaces 16 and 18 of the plates 10 and 12, the face pla-te 10 is placed in face--to-face relationship with the base plate 12 to assume -the orientation shown in Figure 2. ~lowever, prior to this step, the fri-t material has been preglazed or heated in an air or oxygen atmosphere to remove any organic binders in the frit as will be explained later with respect -to the overall method of assembly of the present invelltion .
In order to provide -tight engagement between the face plate 10 and the base plate 12 in Figure 2 a plurality of biasing -clips 34 are placed around the display device 1~. Depending upon the size of the display device either two or four biasing clips 3~ can be utili7.ed. As shown in Figure 3, which is an end view of -the display l~ wi-th the end biasing clip 3~ removed, the sealin~ frit has an irregular surface 35 which in conjunction with the interior surface 1~ of the base plate 12 forms a plural~
ity of vias or openings 36 which permi-t the evacuation of -the interior envelope formed between the face plate 10 and base plate 12 in conjunction wi-th the sealing frit 32. Further, the vias ox openings 36 can be utilized for -the in-troduction of an ionizable gas into the envelope prior to sealin~ of the frit 32.
It should be no-ted that the base plate 12 is wider than the face plate 10 to provide an extended por-tion 38 oF the base ~ J-114 ~L~3~
plate 12 on which the colmection or terminal pads 26 are sitllat~d to create an edge board connection to the electronic circuitry of the device in ~hich the display is to be utilized.
Tllrninq -to the more detailed explanation of the method 5 for constructing the gas discharge display device 1~ a-ttention is directed to Figure l. A plurality of cathode electrodes 22 with a series of electrode conductive runs (not shown) are screen printed on the interior surface 18 of the base plate 12. Further the terminal pads 26 which connect to the conductive runs are deposited along the extended portion 38 of the base pla-te 12.
Subse~uently a dielectric layer 24 is placed over the electrode conductive runs. The dielectric layer 24 has a plurality of apertures or windows 25 which allow for the exposure of the cathode electrode segments 22 to form the character positions 20.
Depending upon the complexity of the character position more than one conductive layer and dielectrlc layer may be necessary.
The face plate 10 in Figure 1 has a plurality of anode electrodes 30 deposited on the interior surface 16 with each anode electrode 30 designed to operate cooperatively a respective character position 20 on the base plate 12. Although the pr~sent lnven-tion shows the anode electrodes 30 being placed on the face plate lO it should be noted that in some arrangements it may be desirable to incorporate the anodes on the base plate 12 to provide a coplanar anode and ca-thode electrode arrangement~
Deposited on the interior surface 16 of the Æace plate lO ls a ~lass frit 32 which is preferably screen deposited~ Located within the fri-t 32 are a plurali-ty of small spacer beads (not shown) which have a higner melt.ing point than the frit material and are designed to provide -the necessary spacing between the ~ace plate lO and the base plate 12 ~7hen the pla-tes are assembled iIl face--to-face relation. `
. . . . ~. , Prior to the assembly of the face plate 10 and the base plate 12 in face-to-face relation, the glass frit 32 is preglazed or heated by placing the face pLate 10 in an oxygen or atmosphere furnace and heated to remove or burn out any organic binders which may be in the glass frit material. Otherwise, the presence oE binders within the glass frit would esta~lish or create a porous sealing material when the frit is subse~uently heated to seal the plates hermetically to~e-ther. In other words, if the binders were burned out at the time that the plates are assembled and the frit is heated to seal the plates, the removal of the binders may result in the exis-tence of voids within the frit which could result in leakage of the ionizable gas from wi-thin the display envelope and could contaminate the gas.
AEter the preglazing s-tep on the frit material 32, the plates are assembled in face-to-face relationship with respect to each o-ther to assume the position or configuration shown in Figure 2. As stated previously, -the width of the face plate 10 is less than the width of the base plate 12 so that a pro-truding edge portion 38 on the base plate to support the terminal connec-tion pads 26 for inser-tion into the electronics of the device in ~hich the display is to be utilized. After the plates are proper-ly oriented with respect to each other, a plurality of the biasing or spring clips 34 are positioned around the display device 1~.
Depending upon the size of the display device, two or four of 2S these clips 3~ may be utilized. The clips not only maintain the proper orientation between the plates, but also provide for in-creased pressure between the plates. The pressure of these clips reduce the temperature and the time required for the sealing step when the frit material is heated to provide the seal between the ~`
pla-tes.
However, prior to the heating of the frit material for sealing the plates toge-ther, the device 1~ is inserted into a !
. ~
. .
1~3~V?~
`vacuu~ furnace wherein a vacuu~ environment is created to withdraw or evacuate the atmosphere within the envelope created between the plates and the frit material 32. Since, as shown in Figure 3, the frit material prior to its heating for sealing has an irregular Æ face 35 to create a plurality of vias 36, the atmosphere within the envelope can easily be withdrawn. After the vacuum environment has been created typically to approximately 10-5 torr at approximately 350C for approximately 5 minutes, an ionizable gas is introduced within the furnace to fill the envelope between the plates through the vias 36. After the ionizable gas has filled the envelope at the proper pressure, the vacuum furnace temperature is raised to the point where the sealing glass frit is melted and devitrified to create a hermetic seal between the plates. As stated previously, located within the frit material are glass beads having a higher melting temperature than the glass frit and will provide the necessary spacing between the plates as the frit material devitrifies. The utilization of the biasing clips 34 greatly decreases the time and temperature necessary to create the hermetic seal by the melting of the glass frit.
By way of example, once the display device 14 has been placed within the vacuum furnace, the temperature is increased to approximately 350C
while the vacuum is being created. The vacuum is held for several minutes after which the temperature is again raised to 480C during which time the introduction of the ionizable gas occurs. Once a temperature of 480C is reached, it is held for approximately 20 minutes to provide for the devitrification of the glass frit. The furnace is then allowed to gradually cool from 480C to 330C for approximately 40 mlnutes and nitrogen is injected into the furnace to approximately one atmosphere to aid in cooling. Finally the displays are cooled to approximately 100C and remov~d from the furnace.
dm~ g _ 1 . ~, ,, , , , . ~ , , , ~ , . .:
_3D-114 It will be appreciated that while the preferred process for making the gas display has been described, cognizance should be taken of the fac-t that it would be apparent to those skilled in tne ar-t that certain obvious modifica-tions such as the use of a vitreous frit may be made to -the present invention wi-thout departing from the true spirit and scope of the claims set forth.
The commonly used method for constructing a gas dis-charge display device incorporates the use of a tubulation port in one of the pla-tes that forms -the display device. A rather fragile tubulation glass chalmel extends away from the display plate adjacent the tubulation port -to provide a channel for the evacuation of the envelope in the display device and for the subsequent in-troduction of an ionizable gas. Once the display is filled with an ionizable gas at the proper pressure, the tubula-tion member is pinched off to seal the display. However, asignificant portion of the tubulation member remains attached to the display device presenting a projection exterior to the dis-play device essen-tially perpendicular to the plane of the display device. Being nlade of glass material, the projecting tubulation `' ' - ' ~.
! r .
' '' ., ' :~i '. . ~ ' ' .
?
iLJL~ ~d is extremely fragile and is susceptible to breakage during packing, trans-porting or use of the display device. Consequently, many displays must be repaired or scrapped when breakage of the tubulation occurs.
! Because of the utilization of a tubulation tube on a gas discharge display device presents a very fragile member in the device, various approaches have been utilized to avoid incorporating the tubulation member.
In one approach a gap is left in the sealing frit material around the perimeter of the viewing area of the display device to provide an exhaust port for evacuating the envelope and an entry port to fill the envelope with the ionizable gas. After the filling of the envelope with the ionizable gas, the gap in the sealing frit is sealed with a sealing material or lcw melting glass plug which is melted to enclose the gap. Examples of such an approach are shcwn in the Kupsky 4,009,407, Hinson 4,013,912 and Przybylek 3,980,366 patents.
Another approach has been to plug the tubulation port with some type of sealing material which is heated to enclose or plug the tubulation port leaving no tubulation extending frcm the exterior surface of the plate. An example of such arrangements are shcwn in the Beckerman et al. 3,914,000 patent and the Frankland et al,4,182,540 patent entitled MEI~iOD OF SE~LING GAS DISCHARGæ DISPLAYS.
Another approach to eliminating the utilization of a tubulation member on the gas display device i5 shcwn in the Wilson 3,778,126 patent wherein a sealing material initially has a permeable ch æ acteristic so that envelope evacuation and gas introduction can be done through the sealing material after which ~he device is heated sufficiently to melt the sealing material and seal the gas within the envelope.
Although many of the above described approaches eliminate the -utilization of a tubulation me~ber on the gas display dm~ 2 -~3~
device, each has certain relative disadvantages. The use of a separate sealing material to plug a gap in the frit of the display device requires special equipment to properly orient the sealing element as well as proper controls or even the use of special heating equipmen-t to provide the necessary heating of the sealing plug. The requirement of special equipment to heat the sealing plug is especially true with respect to the Beckerman patent which utilizes a separate small heating unit which must be placed adjacent the sealing plug to cover the exhaust port in one of the plates of the display.
In most of these approaches the sealing time for the display is considerably longer than desired and in many instances the sealing frit is not properly prepared to provide a satisfactory and reliable seal. Also, in many of the above disclosed approaches the evacuation and gas filling of the display envelope require special equipment connected to each of the display devices.
Summary of the Invention The present invention is a method for making a gas discharge display device without having a tubulation projecting from the display. Specifically, the invention relates to a method for constructing a gas display device having a face plate and a back plate forming an envelope containing display electrodes. The method comprises the steps of s_reen printing a frit material on at least one of the plates; preglazing the frit material in an atmospheric environment to remove all organic binders within the frit material; assembling the plates in face-to-face relation to ~i mb/sb - 3 -;~ :
..
:: . : , - . ~ . .
., ~ :
..
-- ~ 3~ ~d~) form the envelope; placing the plates within a vacuum furnace; evacuating the atmosphere within the envelope through the interface of the frit material and the other of the plates; introducing an ionizable gas into the envelope; andheating the frit material to hermetically seal the plates with no exhaust port in the plates and the frit material~
In its apparatus aspect the invention relates to a gas discharge display device comprising a nonapertured base plate; a nonapertured face plate positioned in face-to-face spaced relation with the base plate to form an envelope; a screen printed preglazed frit material located between the plates to form a perimeter seal around the plates to hermetically seal the plates, the frit material bein~ continuous throughout the perimeter around the plates, the frit material prior to establishing the hermetic seal providing passageways for the evacuation and backfilling of the envelope, the frit material having substantially no organic binder material when the hermetic seal is formed, means in the frit material for maintaining the space between the plates; an ionizable gas within the envelope; and electrodes within the envelope for selectively activating the gas to provide a visible message, the device having no fill ports for the introduction of the gas into the envelope.
Thus, the process of the present invention prepares :
the sealing frit in such a manner that it is preglazed to remove any organic binders from the sealing frit, so that, when it is heated for sealing between the plates of the 1- mb/~ ~ 3a -~ .
. . -, ,... ,; ~ , , , , ,.'. , ~ '`,: . ,, . : , ' :` ' ' display, a rellable and permanent seal i5 established.
Also incorporated in the present invention is the utilization of biasing means attached between the plates when they are assembled in face-to-face relation so that during the heating step to provide the seal between the plates the time required is significantly reduced and the seal is greatly improved.
The irregularities in the sealing frit prior to its heating for sealing provides the necessary passageways for the : mb/ l - 3b -. . . ~ . .: ,: .
. . . , : , -, 4~ 114 evacuation and filling of the envelope in a vacuum furnace prior to the sealing of the plates. The use of the vacuum furnace allows Eor the simultaneolls evacuation and ~illing of several display devices without the need of any special connecting equip-ment be-tween each display and a vacuum source as well as an ionizable gas source.
Conse~uently, the present invention not only eliminates the use of a tubulation in -the device, but also eliminates the requirement for a special aperture in eitller of the plates or in the sealing frit as an evacuation and gas filling port. In addition, the present invention utilizes a method -to reduce the time required during the heating cycle for sealing the plates together with the sealing frit or material. The use of the biasing means also allows for a reduction in the temperature re-quired for the proper sealing.
Without the proper preparation of the sealing frit by a preglaxing process in an air or oxygen environment -to remove -the organic binders, the frit upon melting for sealing may have a porosity which would result in a nonhermetic seal.
The present invention also u-tilizes a sealing frit ..
which is screened onto -the perimeter of one of the face plates.
The heating of the sealing frit to hermetically seal the pla-tes together results in a devi-tri:Eication of the frit.
In summary, the present invention teaches a method for making a gas display device without a tubulation member in such a manner -that not only the -time, but also -the temperature required to seal the pla-tes is reduced, and the frit is prepared in such a manner that i-t will create a reliable and hermetic sea:L between the plates which is extremely important to the gas fil].ed enve-lope of the display.
P,rief _e~c~e~ of the Dra~in~s Figure l is a pe:Lspective vi.ew of a display device :~
_~_ `, . .
` ~2~-114 ~3~
prior to assembly of the plates, showing the interior surface of each of the plates;
Figure 2 is a perspective view of the plates asiembled in a display device with biasing means attached to the plates;
Figure 3 i5 an enlarged end view with one of the bias-ing means removed showing the irregularities of the sealing frit prior to heating of -the sealing frit to sealed plates; and Figure 4 is an enlarged end view of the device similar to Figure 3 showing the sealing frit after it has been heated to create the seal be-tween the respective plates.
De-tailed Description of the Invention In Figure 1 the face plate 10 and the base pla-te 12 of a gas discharge display 14 are shown prior to assembly with the interior surfaces 16 and 13 of the respective face plate 10 and base plate 12 exposed. Located on the interior surface 18 of the base plate 12 is an electrode pattern comprised of a plurality of character positions 20 formed by a series of separate cathode electrode segments 22. A dielectric layer 24 covers the electrode conductive runs which have been screened on the base plate 12 to properly interconnect the appropriate cathode segments 22 with the terminal pads 26 located along the longitudinal edge 28 of tlle base plate 12. Both the electrode pa-ttern and the dielectric layer 24 are preferably screen printed on the interior surface 18 of the base pla-te 12.
~eposited on the interior surface 16 of the face pla-te 10 are a plurality of anode electrodes 30 which are designed to operate in conjunction with each of the character positions 20 on the base plate 12. The anodes 30 are preferably made of a trans-parent material such as tin oxide. Each of the anodes 30 is ~-connected to a respec-tive terminal pad 26 by a clip (not shown) placed between the plates. Located around -the per.~phery of the anodes 30 is a sealing frit 32. The sealing frit 32 is prefera-, .` ; ' ' . . : ,-~' , ' ' ' ' ' ' '~.J~ 3~2 ~ bly screen printed on-to the face plate. One preferable material -~i` is Corning 75~5 frit although Corning 7555 is another frit material to use. Glass beads, not shown, are in the sealing frit so that, when the frit melts, tlle glass beads will establish the necessary spacing between the plates when they are assembled. It should be noted that the cathode electrodes 22 and the anodes 30 could be placed on the base plate 12 in a coplanar relationship.
Once the cathode electrodes 22, the anode electrodes 30, the dielectric layer 24 and the sealing frit 32 have been properly placed on the respective interior surfaces 16 and 18 of the plates 10 and 12, the face pla-te 10 is placed in face--to-face relationship with the base plate 12 to assume -the orientation shown in Figure 2. ~lowever, prior to this step, the fri-t material has been preglazed or heated in an air or oxygen atmosphere to remove any organic binders in the frit as will be explained later with respect -to the overall method of assembly of the present invelltion .
In order to provide -tight engagement between the face plate 10 and the base plate 12 in Figure 2 a plurality of biasing -clips 34 are placed around the display device 1~. Depending upon the size of the display device either two or four biasing clips 3~ can be utili7.ed. As shown in Figure 3, which is an end view of -the display l~ wi-th the end biasing clip 3~ removed, the sealin~ frit has an irregular surface 35 which in conjunction with the interior surface 1~ of the base plate 12 forms a plural~
ity of vias or openings 36 which permi-t the evacuation of -the interior envelope formed between the face plate 10 and base plate 12 in conjunction wi-th the sealing frit 32. Further, the vias ox openings 36 can be utilized for -the in-troduction of an ionizable gas into the envelope prior to sealin~ of the frit 32.
It should be no-ted that the base plate 12 is wider than the face plate 10 to provide an extended por-tion 38 oF the base ~ J-114 ~L~3~
plate 12 on which the colmection or terminal pads 26 are sitllat~d to create an edge board connection to the electronic circuitry of the device in ~hich the display is to be utilized.
Tllrninq -to the more detailed explanation of the method 5 for constructing the gas discharge display device 1~ a-ttention is directed to Figure l. A plurality of cathode electrodes 22 with a series of electrode conductive runs (not shown) are screen printed on the interior surface 18 of the base plate 12. Further the terminal pads 26 which connect to the conductive runs are deposited along the extended portion 38 of the base pla-te 12.
Subse~uently a dielectric layer 24 is placed over the electrode conductive runs. The dielectric layer 24 has a plurality of apertures or windows 25 which allow for the exposure of the cathode electrode segments 22 to form the character positions 20.
Depending upon the complexity of the character position more than one conductive layer and dielectrlc layer may be necessary.
The face plate 10 in Figure 1 has a plurality of anode electrodes 30 deposited on the interior surface 16 with each anode electrode 30 designed to operate cooperatively a respective character position 20 on the base plate 12. Although the pr~sent lnven-tion shows the anode electrodes 30 being placed on the face plate lO it should be noted that in some arrangements it may be desirable to incorporate the anodes on the base plate 12 to provide a coplanar anode and ca-thode electrode arrangement~
Deposited on the interior surface 16 of the Æace plate lO ls a ~lass frit 32 which is preferably screen deposited~ Located within the fri-t 32 are a plurali-ty of small spacer beads (not shown) which have a higner melt.ing point than the frit material and are designed to provide -the necessary spacing between the ~ace plate lO and the base plate 12 ~7hen the pla-tes are assembled iIl face--to-face relation. `
. . . . ~. , Prior to the assembly of the face plate 10 and the base plate 12 in face-to-face relation, the glass frit 32 is preglazed or heated by placing the face pLate 10 in an oxygen or atmosphere furnace and heated to remove or burn out any organic binders which may be in the glass frit material. Otherwise, the presence oE binders within the glass frit would esta~lish or create a porous sealing material when the frit is subse~uently heated to seal the plates hermetically to~e-ther. In other words, if the binders were burned out at the time that the plates are assembled and the frit is heated to seal the plates, the removal of the binders may result in the exis-tence of voids within the frit which could result in leakage of the ionizable gas from wi-thin the display envelope and could contaminate the gas.
AEter the preglazing s-tep on the frit material 32, the plates are assembled in face-to-face relationship with respect to each o-ther to assume the position or configuration shown in Figure 2. As stated previously, -the width of the face plate 10 is less than the width of the base plate 12 so that a pro-truding edge portion 38 on the base plate to support the terminal connec-tion pads 26 for inser-tion into the electronics of the device in ~hich the display is to be utilized. After the plates are proper-ly oriented with respect to each other, a plurality of the biasing or spring clips 34 are positioned around the display device 1~.
Depending upon the size of the display device, two or four of 2S these clips 3~ may be utilized. The clips not only maintain the proper orientation between the plates, but also provide for in-creased pressure between the plates. The pressure of these clips reduce the temperature and the time required for the sealing step when the frit material is heated to provide the seal between the ~`
pla-tes.
However, prior to the heating of the frit material for sealing the plates toge-ther, the device 1~ is inserted into a !
. ~
. .
1~3~V?~
`vacuu~ furnace wherein a vacuu~ environment is created to withdraw or evacuate the atmosphere within the envelope created between the plates and the frit material 32. Since, as shown in Figure 3, the frit material prior to its heating for sealing has an irregular Æ face 35 to create a plurality of vias 36, the atmosphere within the envelope can easily be withdrawn. After the vacuum environment has been created typically to approximately 10-5 torr at approximately 350C for approximately 5 minutes, an ionizable gas is introduced within the furnace to fill the envelope between the plates through the vias 36. After the ionizable gas has filled the envelope at the proper pressure, the vacuum furnace temperature is raised to the point where the sealing glass frit is melted and devitrified to create a hermetic seal between the plates. As stated previously, located within the frit material are glass beads having a higher melting temperature than the glass frit and will provide the necessary spacing between the plates as the frit material devitrifies. The utilization of the biasing clips 34 greatly decreases the time and temperature necessary to create the hermetic seal by the melting of the glass frit.
By way of example, once the display device 14 has been placed within the vacuum furnace, the temperature is increased to approximately 350C
while the vacuum is being created. The vacuum is held for several minutes after which the temperature is again raised to 480C during which time the introduction of the ionizable gas occurs. Once a temperature of 480C is reached, it is held for approximately 20 minutes to provide for the devitrification of the glass frit. The furnace is then allowed to gradually cool from 480C to 330C for approximately 40 mlnutes and nitrogen is injected into the furnace to approximately one atmosphere to aid in cooling. Finally the displays are cooled to approximately 100C and remov~d from the furnace.
dm~ g _ 1 . ~, ,, , , , . ~ , , , ~ , . .:
_3D-114 It will be appreciated that while the preferred process for making the gas display has been described, cognizance should be taken of the fac-t that it would be apparent to those skilled in tne ar-t that certain obvious modifica-tions such as the use of a vitreous frit may be made to -the present invention wi-thout departing from the true spirit and scope of the claims set forth.
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for constructing a gas display device having a face plate and a back plate forming an envelope containing display electrodes, said method comprising the steps of screen printing a frit material on at least one of said plates; preglazing said frit material in an atmospheric environment to remove all organic binders within said frit material; assembling said plates in face-to-face relation to form said envelope; placing said plates within a vacuum furnace; evacuating the atmosphere within said envelope through the interface of said frit material and the other of said plates; introducing an ionizable gas into said envelope; and heating said frit material to hermetically seal said plates with no exhaust port in said plates and said frit material.
2. A method for constructing a gas display device as defined in claim 1 and after said assembling step additionally comprising the step of attaching biasing means to said plates to force said plates into tighter engagement with each other so that the time and temperature required to seal said plates as compared to the time and temperature required to seal said plates without said biasing means is reduced.
3. A method for constructing a gas display device as defined in claim 1, wherein said frit material is a glass and devitrifies during said heating step.
4. A method for constructing a gas display device as defined in claim 1, wherein said frit material contains glass beads having a higher melting temperature than said frit material so that during said heating step said glass beads establish the proper base plate and back plate spacing.
5. A method for constructing a gas display device as defined in claim 2, wherein said biasing means comprise compression springs which are connected to both the face plate and the back plate during said attaching step to hold said plates in tight engagement with each other.
6. A method for constructing a gas display device as defined in claim 1, wherein said evacuating step comprises at least a vacuum environment of approximately 10-5 torr at approximately 350°C for approximately 5 minutes.
7. A method for constructing a gas display device as defined in claim 1, wherein said introducing step comprises the raising of the temperature from approximately 350°C to approximately 480°C for a period of approximately 20 minutes, said ionizable gas being introduced into said envelope when the temperature is below the flow point of the frit at approximately 350°C.
8. A method for constructing a gas display device as defined in claim 1, wherein said heating step comprises maintaining a temperature of substantially 480°C
for approximately 20 minutes.
9. A gas discharge display device comprising a nonapertured base plate; a nonapertured face plate positioned in face-to-face spaced relation with said base plate to form an envelope; a screen printed preglazed frit material located between said plates to form a perimeter seal around said
for approximately 20 minutes.
9. A gas discharge display device comprising a nonapertured base plate; a nonapertured face plate positioned in face-to-face spaced relation with said base plate to form an envelope; a screen printed preglazed frit material located between said plates to form a perimeter seal around said
Claim 9...continued.
plates to hermetically seal said plates, said frit material being continuous throughout the perimeter around said plates, said frit material prior to establishing said hermetic seal providing passageways for the evacuation and backfilling of said envelope, said frit material having substantially no organic binder material when said hermetic seal is formed, means in said frit material for maintaining the space between said plates; an ionizable gas within said envelope; and electrodes within said envelope for selectively activating said gas to provide a visible message, said device having no fill ports for the introduction of said gas into said envelope.
plates to hermetically seal said plates, said frit material being continuous throughout the perimeter around said plates, said frit material prior to establishing said hermetic seal providing passageways for the evacuation and backfilling of said envelope, said frit material having substantially no organic binder material when said hermetic seal is formed, means in said frit material for maintaining the space between said plates; an ionizable gas within said envelope; and electrodes within said envelope for selectively activating said gas to provide a visible message, said device having no fill ports for the introduction of said gas into said envelope.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US91584478A | 1978-06-15 | 1978-06-15 | |
| US915,844 | 1978-06-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1136202A true CA1136202A (en) | 1982-11-23 |
Family
ID=25436339
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000328225A Expired CA1136202A (en) | 1978-06-15 | 1979-05-24 | Method of sealing a gas discharge display without a tubulation |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS551099A (en) |
| CA (1) | CA1136202A (en) |
| DE (1) | DE2924274A1 (en) |
| GB (1) | GB2029084B (en) |
| NL (1) | NL7904634A (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2133210A (en) * | 1983-01-07 | 1984-07-18 | Philips Electronic Associated | Envelope for a cathode-ray tube |
| JPS59147155A (en) * | 1983-02-09 | 1984-08-23 | Daikin Mfg Co Ltd | Power transmission mechanism with fluid coupling |
| GB2142391B (en) * | 1983-07-01 | 1986-03-26 | Honda Motor Co Ltd | Control device for a direct clutch in automatic transmission |
| JP2521475B2 (en) * | 1987-06-05 | 1996-08-07 | 株式会社佐竹製作所 | Grain sample crusher |
| FR2718285B1 (en) * | 1994-03-31 | 1996-06-21 | Pixel Int Sa | Process for manufacturing flat vacuum tubes without piping, and products obtained by this process. |
| FR2781308A1 (en) * | 1998-07-15 | 2000-01-21 | Thomson Plasma | Display panel spacers, especially for plasma display panels, are produced by applying deposits of height defining the panel sheet spacing onto one of the panel sheets |
| JP5068924B2 (en) * | 2004-02-20 | 2012-11-07 | 中外炉工業株式会社 | Continuous sealing processing furnace and sealing processing method for glass panel assembly |
| KR101176056B1 (en) * | 2004-12-01 | 2012-08-24 | 엘리노 인더스트리에-오펜바우 게엠바하 | Method and device for producing units for creating flat-panel monitors and the like, and device for evacuating/filling the intermediate space within such units |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3778126A (en) * | 1971-12-30 | 1973-12-11 | Ibm | Gas display panel without exhaust tube structure |
| JPS5315749A (en) * | 1976-07-28 | 1978-02-14 | Ise Electronics Corp | Vacuum display tube |
-
1979
- 1979-05-24 CA CA000328225A patent/CA1136202A/en not_active Expired
- 1979-05-29 GB GB7918648A patent/GB2029084B/en not_active Expired
- 1979-06-13 NL NL7904634A patent/NL7904634A/en not_active Application Discontinuation
- 1979-06-15 JP JP7474979A patent/JPS551099A/en active Pending
- 1979-06-15 DE DE19792924274 patent/DE2924274A1/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| JPS551099A (en) | 1980-01-07 |
| NL7904634A (en) | 1979-12-18 |
| GB2029084A (en) | 1980-03-12 |
| GB2029084B (en) | 1982-07-28 |
| DE2924274A1 (en) | 1979-12-20 |
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| MKEX | Expiry |