CA1150340A - Cathode unit for fluorescent tube - Google Patents
Cathode unit for fluorescent tubeInfo
- Publication number
- CA1150340A CA1150340A CA000364156A CA364156A CA1150340A CA 1150340 A CA1150340 A CA 1150340A CA 000364156 A CA000364156 A CA 000364156A CA 364156 A CA364156 A CA 364156A CA 1150340 A CA1150340 A CA 1150340A
- Authority
- CA
- Canada
- Prior art keywords
- cathode
- shield
- tube
- disc
- hole
- 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
- H01J61/00—Gas-discharge or vapour-discharge lamps
- H01J61/02—Details
- H01J61/04—Electrodes; Screens; Shields
Landscapes
- Discharge Lamp (AREA)
- Vessels And Coating Films For Discharge Lamps (AREA)
- Electrodes For Cathode-Ray Tubes (AREA)
- Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
- Nitrogen Condensed Heterocyclic Rings (AREA)
- Discharge Lamps And Accessories Thereof (AREA)
- Physical Vapour Deposition (AREA)
Abstract
Abstract The present invention refers to a cathode unit intended for use in a fluorescent tube and designed in such a way that the service life of the tube is increased markedly as a result of a reduction in the loss of emission mater-ial from the cathode. These material losses are caused by, inter alia, ion bombardment and by vaporization of the emission material. In order to achieve a marked increase in the reflection of released atoms and molecules back to the cathode surface, both atoms and molecules which have been released through ion bombardment and atoms and molecules which have been vaporized from the cathode surface, the cathode is surrounded by an electrically conductive cathode shield in the form of a box-shaped casing which is electrically insulated from the cathode. An opening is made in the bottom of the shield for inserting the cathode. The open end of the shield is closed by means of a disc, preferably made of mica and provided with a centrally located hole. The hole diameter of the mica disc should be selected so that it is as small as possible while bearing in mind the fact that the starting voltage for the tube should not exceed a predetermined value.
Description
~5~340 The present invention refers to a cathode unit for a fluorescent tube with a cathode which is permanently mounted in relation to the tube wall and which is surrounded by a cathode shield which consists of electrically conduc-tive material and which is not connected electrically to the cathode.
The service life for a fluorescent tube counted in hours of burning time is determined mainly by the service life of the tube cathodes. When the cathodes have lost a certain portion of their emission material consisting of alkaline earth oxides, their electron emitting capacity drops to such an extent that the tube will either not start or will enter a flickering stage which rapidly pulverizes the remaining emission material.
It is well known that surplus barium dissolved in the mixed crystals of the emission material makes the alkaline earth oxides semiconductive and reduce the liberation work of the electrons. This surplus barium is formed through a chemical reaction between barium oxide and tungsten in accordance with the following equation. _ ~
6 BaO + W ~ Ba3W06 + 3 Ba t ~r~State The barium tuugst4n thus formed remains as an intermediate layer between the tungsten and the actual emission substance throughout the service life of the cathodes while the barium is continuously diffused as vapour through the substance.
Sta ~ c, The barium ~ffRgs*en layer entails a damping of the reaction according to the above formula, i.e. a reduced formation of barium. As a result of this, all of the barium will not have been vaporized until after about 30,000 hours of continuous burning of a normal fluorescent tube. The stresses on the tube cathodes during the starting process are, however, so large that the service life is reduced by a factor of 2-3 during the normal use of a fluorescent tube, i.e. with a mean connection period of 2-3 hours a time. ~
~15~340 Loss of the cathode material which serves as emission substances and the resultant reduction in the service life of the fluorescent tube is caused, in principleJ by three different processes, namely 1) removal of emission material due to ion bombardment, particularly in conjunction with insufficient cathode temperatures; 2) vaporization of emission material; and 3) chemical reactions between the emission material and gaseous impurities in the tube.
In the design of a fluorescent tube intended for an extremely long service life during which the tube will be ignited and extinguished a consider-able number of times, the tube cathodes must be designed in such a way that lQ these three reasons for reduced cathode service life are taken fully into account.
A prerequisite for the removal of emission material due to ion bom-bardment is, in principle, that each atom which leaves the cathode surface never returns to the cathode. This is, however, only true in a vacuum. In reality the cathode is surrounded in a normal fluorescent tube construction by a rare gas atmosphere with a pressure of about 2.5 x 10 Pa. Consequently, the free /en qt~ ~f rnd~en~
medium usYe~el~h for the atoms and molecules released from the surface is con-siderably shorter than the distance between the cathode and the tube wall. As a result, many of the released atoms and molecules are reflected back and fall in towards the cathode surface. This considerably reduces the material loss.
Such a reduction is, however, insufficient in the case of cathodes for long-life tubes.
The vaporization of the emission substance is comparatively constant during continuous operation but takes place more rapidly after each start and in the minutes following a start due to the increased cathode temperature.
This means that a cathode for a long-life tube must be designed so that vapor-ized atoms and molecules are reflected back to the cathode surface to a con-siderable extent and so that the cathode temperature remains moderate during the actual start period.
. ~ ~ , ; , . . ~
3~0 The purpose of the present inyention ~s to solye the problems out-lined above and thus to achieve a cathode design which is intended for use in a fluorescent tube and which markedly increases the service life of the tube.
According to the invention, the cathode shield is generally box-shaped, preferably cylindrical, with a bottom provided with an opening permit-tlng the cathode to be inserted into the interior of the shield, and having an open end closed by a disc provided with a centrally located hole and made of electrically insulating material. A cathode unit of this type causes atoms and molecules which have been released from a cathode surface through ion bombard-ment and atoms and molecules which have been vaporized from the cathode surface to be reflected back to the cathode surface to a far greater extent.
The cathode shield should preferably consist of iron or nickel. The disc, which must consist of a material ~hich is not pulveri~ed during the ion bombardment, can consist to advantage of mica.
The hole in the disc must have as small a diameter as possible so as to reduce the blackening of the inside of the tube wall to a minimum. Too small a hole diameter will, howeverJ mean that the starting voltage of the fluorescent tube will rise in undesirable manner. Consequently, the hole in the disc should have a diameter which is as small as possible while bearing in mind the fact that the starting voltage of the tube may not exceed a predetermined value.
The most suitable hole diameter for a normal fluorescent tube with a tube dia-meter of 38 mm has proved to be 10-12 mm.
Since undesirable chemical reactions between the emission material and gaseous impurities in the tube can be disastrous for the service life of the tube, it is of the greatest importance that an efficient pump process be used when manufacturing the tube to remove all traces of different gases. Experience has shown that the most efficient pump process is achieved in an automatic pump ~5~3~0 unit where vacuum pumping under high temperature is oombined with internal pump-ing achieved by feeding mercury drops into the hot fluorescent tube. ~hen the mercury drops strike the fluorescent tube they are vaporized explosively and give rise to a diffusion pump effect in the fluorescent tube. This entails an extremely efficient removal of impurities. If this is to take place to a sufficient extent it is, however, essential that the cathode does not exercise any restrictive effect on the efficiency on the abovementioned pump process.
For this reason the opening in the bottom of the cathode shield should prefer-ably have an area which is at least equal in size to the area of the hole in thedisc.
The invention will ncw be described in greater detail with referen oe to the accompanying drawings, in which:
Figure 1 is a fragmentary sectional view showing one end of a fluores-cent tube provided with a cathode unit designed and constructed in accordan oe with the invention;
Figures 2a and 2b show - in a vertical cross section and from beneath, respectively, a cathode shield used in the cathode unit of Figure l;
Figure 3 shows, in plan, a mica disc which covers the open end of the cathode shield illustrated in Figure 2a and Figure 2b; and Figure 4 is a chart which illustrates the dependency of the starting voltage and the degree of blackening on the hole diameter of the mica disc.
Figure 1 shows, in section, one end of a fluorescent tube designed and constructed in accordance with the invention. The glass wall 1 of the tube is sealed by a foot 2 at one end in the conventional manner. This foot serves simultaneously as a base for cathode supports 4 which support a spiral cathode 3.
These cathode supports, which are electrically conductive, are oonnected by means of supply wires 5 fused into the foot 2 through which current can be made to pass through the cathode 3 and heat up the cathode. m e cathode 3 is ~15~340 surrounded by a cathode shield 6 which should preferably be of iron or nickel.
The shield 6 is supported by a brace 7 fused into the foot 2 and is electrically insulated from the cathode 3.
As can be seen most clearly from Figures 2a and 2b, the cathode shield 6 is shaped like a cylindrical box, in the bottom of which an oblong opening 8 has been made for free reception of the cathode 3 and parts of the cathode supports 4. The open end of the cathode shield 6 is closed with the aid of a mica disc 9, the thickness of which should preferably be in the range 0.10 -1.15 mm. As can be seen from Figure 3, the mica disc 9 is provided with a centrally located hole 10, preferably circular in shape. The hole 10 has a diameter of 10 - 12 mm for a normal fluorescent tube with a tube diameter of 38 mm. A smaller diameter than this will, admittedly, reduce the blackening of the inside of the tube wall but will, simultaneously, increase the starting vol-tage to unacceptable values, as is illustrated in Figure 4, which shows the starting voltage U in volts as well as the relative degree of blackening S as a function of the diameter Dlo in mm of the hole 1. A larger hole diameter will reduce the starting voltage only insignificantly but will increase the blackening of the tube wall considerably.
It is important that the disc 9 be of mica or some other electrically non-conductive material which does not emit a gas since the ion bombardment would, if the disc were made, for example, of iron, give rise to further pulver-ized material and thus increase the blackening of the tube wall.
The design described above offers a further advantage which occurs during the half periods when the spiral acts as an anode. Since the discharge must pass through the mica disc 9 provided with a hole, a marked increase will be obtained in the electron density adjacent to the spiral 3 which functions as an anode. The anode drop will thus be reduced. This will entail a reduction .
:' :
~15~3~0 in the cathode temperature and thus reduce the rate of vaporization.
As has been mentioned earlier, it is desirable that the tube be evacuated by means of a pump process in which vacuum pumping is combined with "internal pumping" achieved by permitting mercury drops to strike the hot tube.
A drop of this type is illustrated schematically at 11 in Figure 1. When the drop strikes the heated fluorescent tube ~wall 1 and/or foot 2) it is vaporized explosively and the mercury vapour thus formed will rapidly flow out. The arrows 12 and 13 indicate in a schematic manner the most important flow paths taken by the vapour. The mercury vapour which follows the path marked by the arrow 13 must not be obstructed by the construction formed from the cathode shield 6 and the mica disc 9 if the carbon dioxide which exists at the emission layer and which was formed through conyersion from carbonates to oxides is to be removed efficiently and if the internal pumping is to be effective. For this reason the hole diameter in the mica disc 9 should exceed 10 mm (for a fluo-rescent tube with a tube diameter of 38 mm) and the bottom opening 8 in the cathode shield 6 must have an area which is at least as large as the hole area of the mica disc but preferably larger.
The cathode design described above makes it possible, while retaining a normal burning time of 3 hours per connection, to achieve a service life which is 3 - 4 times longer than that of conventional fluorescent tubes.
~ ,~ ,..
The service life for a fluorescent tube counted in hours of burning time is determined mainly by the service life of the tube cathodes. When the cathodes have lost a certain portion of their emission material consisting of alkaline earth oxides, their electron emitting capacity drops to such an extent that the tube will either not start or will enter a flickering stage which rapidly pulverizes the remaining emission material.
It is well known that surplus barium dissolved in the mixed crystals of the emission material makes the alkaline earth oxides semiconductive and reduce the liberation work of the electrons. This surplus barium is formed through a chemical reaction between barium oxide and tungsten in accordance with the following equation. _ ~
6 BaO + W ~ Ba3W06 + 3 Ba t ~r~State The barium tuugst4n thus formed remains as an intermediate layer between the tungsten and the actual emission substance throughout the service life of the cathodes while the barium is continuously diffused as vapour through the substance.
Sta ~ c, The barium ~ffRgs*en layer entails a damping of the reaction according to the above formula, i.e. a reduced formation of barium. As a result of this, all of the barium will not have been vaporized until after about 30,000 hours of continuous burning of a normal fluorescent tube. The stresses on the tube cathodes during the starting process are, however, so large that the service life is reduced by a factor of 2-3 during the normal use of a fluorescent tube, i.e. with a mean connection period of 2-3 hours a time. ~
~15~340 Loss of the cathode material which serves as emission substances and the resultant reduction in the service life of the fluorescent tube is caused, in principleJ by three different processes, namely 1) removal of emission material due to ion bombardment, particularly in conjunction with insufficient cathode temperatures; 2) vaporization of emission material; and 3) chemical reactions between the emission material and gaseous impurities in the tube.
In the design of a fluorescent tube intended for an extremely long service life during which the tube will be ignited and extinguished a consider-able number of times, the tube cathodes must be designed in such a way that lQ these three reasons for reduced cathode service life are taken fully into account.
A prerequisite for the removal of emission material due to ion bom-bardment is, in principle, that each atom which leaves the cathode surface never returns to the cathode. This is, however, only true in a vacuum. In reality the cathode is surrounded in a normal fluorescent tube construction by a rare gas atmosphere with a pressure of about 2.5 x 10 Pa. Consequently, the free /en qt~ ~f rnd~en~
medium usYe~el~h for the atoms and molecules released from the surface is con-siderably shorter than the distance between the cathode and the tube wall. As a result, many of the released atoms and molecules are reflected back and fall in towards the cathode surface. This considerably reduces the material loss.
Such a reduction is, however, insufficient in the case of cathodes for long-life tubes.
The vaporization of the emission substance is comparatively constant during continuous operation but takes place more rapidly after each start and in the minutes following a start due to the increased cathode temperature.
This means that a cathode for a long-life tube must be designed so that vapor-ized atoms and molecules are reflected back to the cathode surface to a con-siderable extent and so that the cathode temperature remains moderate during the actual start period.
. ~ ~ , ; , . . ~
3~0 The purpose of the present inyention ~s to solye the problems out-lined above and thus to achieve a cathode design which is intended for use in a fluorescent tube and which markedly increases the service life of the tube.
According to the invention, the cathode shield is generally box-shaped, preferably cylindrical, with a bottom provided with an opening permit-tlng the cathode to be inserted into the interior of the shield, and having an open end closed by a disc provided with a centrally located hole and made of electrically insulating material. A cathode unit of this type causes atoms and molecules which have been released from a cathode surface through ion bombard-ment and atoms and molecules which have been vaporized from the cathode surface to be reflected back to the cathode surface to a far greater extent.
The cathode shield should preferably consist of iron or nickel. The disc, which must consist of a material ~hich is not pulveri~ed during the ion bombardment, can consist to advantage of mica.
The hole in the disc must have as small a diameter as possible so as to reduce the blackening of the inside of the tube wall to a minimum. Too small a hole diameter will, howeverJ mean that the starting voltage of the fluorescent tube will rise in undesirable manner. Consequently, the hole in the disc should have a diameter which is as small as possible while bearing in mind the fact that the starting voltage of the tube may not exceed a predetermined value.
The most suitable hole diameter for a normal fluorescent tube with a tube dia-meter of 38 mm has proved to be 10-12 mm.
Since undesirable chemical reactions between the emission material and gaseous impurities in the tube can be disastrous for the service life of the tube, it is of the greatest importance that an efficient pump process be used when manufacturing the tube to remove all traces of different gases. Experience has shown that the most efficient pump process is achieved in an automatic pump ~5~3~0 unit where vacuum pumping under high temperature is oombined with internal pump-ing achieved by feeding mercury drops into the hot fluorescent tube. ~hen the mercury drops strike the fluorescent tube they are vaporized explosively and give rise to a diffusion pump effect in the fluorescent tube. This entails an extremely efficient removal of impurities. If this is to take place to a sufficient extent it is, however, essential that the cathode does not exercise any restrictive effect on the efficiency on the abovementioned pump process.
For this reason the opening in the bottom of the cathode shield should prefer-ably have an area which is at least equal in size to the area of the hole in thedisc.
The invention will ncw be described in greater detail with referen oe to the accompanying drawings, in which:
Figure 1 is a fragmentary sectional view showing one end of a fluores-cent tube provided with a cathode unit designed and constructed in accordan oe with the invention;
Figures 2a and 2b show - in a vertical cross section and from beneath, respectively, a cathode shield used in the cathode unit of Figure l;
Figure 3 shows, in plan, a mica disc which covers the open end of the cathode shield illustrated in Figure 2a and Figure 2b; and Figure 4 is a chart which illustrates the dependency of the starting voltage and the degree of blackening on the hole diameter of the mica disc.
Figure 1 shows, in section, one end of a fluorescent tube designed and constructed in accordance with the invention. The glass wall 1 of the tube is sealed by a foot 2 at one end in the conventional manner. This foot serves simultaneously as a base for cathode supports 4 which support a spiral cathode 3.
These cathode supports, which are electrically conductive, are oonnected by means of supply wires 5 fused into the foot 2 through which current can be made to pass through the cathode 3 and heat up the cathode. m e cathode 3 is ~15~340 surrounded by a cathode shield 6 which should preferably be of iron or nickel.
The shield 6 is supported by a brace 7 fused into the foot 2 and is electrically insulated from the cathode 3.
As can be seen most clearly from Figures 2a and 2b, the cathode shield 6 is shaped like a cylindrical box, in the bottom of which an oblong opening 8 has been made for free reception of the cathode 3 and parts of the cathode supports 4. The open end of the cathode shield 6 is closed with the aid of a mica disc 9, the thickness of which should preferably be in the range 0.10 -1.15 mm. As can be seen from Figure 3, the mica disc 9 is provided with a centrally located hole 10, preferably circular in shape. The hole 10 has a diameter of 10 - 12 mm for a normal fluorescent tube with a tube diameter of 38 mm. A smaller diameter than this will, admittedly, reduce the blackening of the inside of the tube wall but will, simultaneously, increase the starting vol-tage to unacceptable values, as is illustrated in Figure 4, which shows the starting voltage U in volts as well as the relative degree of blackening S as a function of the diameter Dlo in mm of the hole 1. A larger hole diameter will reduce the starting voltage only insignificantly but will increase the blackening of the tube wall considerably.
It is important that the disc 9 be of mica or some other electrically non-conductive material which does not emit a gas since the ion bombardment would, if the disc were made, for example, of iron, give rise to further pulver-ized material and thus increase the blackening of the tube wall.
The design described above offers a further advantage which occurs during the half periods when the spiral acts as an anode. Since the discharge must pass through the mica disc 9 provided with a hole, a marked increase will be obtained in the electron density adjacent to the spiral 3 which functions as an anode. The anode drop will thus be reduced. This will entail a reduction .
:' :
~15~3~0 in the cathode temperature and thus reduce the rate of vaporization.
As has been mentioned earlier, it is desirable that the tube be evacuated by means of a pump process in which vacuum pumping is combined with "internal pumping" achieved by permitting mercury drops to strike the hot tube.
A drop of this type is illustrated schematically at 11 in Figure 1. When the drop strikes the heated fluorescent tube ~wall 1 and/or foot 2) it is vaporized explosively and the mercury vapour thus formed will rapidly flow out. The arrows 12 and 13 indicate in a schematic manner the most important flow paths taken by the vapour. The mercury vapour which follows the path marked by the arrow 13 must not be obstructed by the construction formed from the cathode shield 6 and the mica disc 9 if the carbon dioxide which exists at the emission layer and which was formed through conyersion from carbonates to oxides is to be removed efficiently and if the internal pumping is to be effective. For this reason the hole diameter in the mica disc 9 should exceed 10 mm (for a fluo-rescent tube with a tube diameter of 38 mm) and the bottom opening 8 in the cathode shield 6 must have an area which is at least as large as the hole area of the mica disc but preferably larger.
The cathode design described above makes it possible, while retaining a normal burning time of 3 hours per connection, to achieve a service life which is 3 - 4 times longer than that of conventional fluorescent tubes.
~ ,~ ,..
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A cathode unit for a fluorescent tube with a cathode permanently mounted in relation to the tube wall and surrounded by a cathode shield which is not electrically connected to the cathode and which consists of electrically conductive material, wherein the cathode shield is generally box-shaped having a bottom provided with an opening made for inserting the cathode into the inter-ior of the shield and having an open end closed by means of a disc provided with a centrally located hole and made of electrically insulating material.
2. A cathode unit in accordance with Claim 1, wherein the cathode shield consists of iron or nickel.
3. A cathode unit in accordance with Claim 1 or Claim 2, wherein the disc is made of mica.
4. A cathode unit in accordance with Claim 1 or Claim 2 wherein the hole in the disc has a diameter which is selected so that it is as small as possible consistent with an acceptable level of starting voltage.
5. A cathode unit in accordance with Claim 1 or Claim 2, wherein the opening in the bottom of the cathode shield has an area which is at least as large as the area of the hole in the disc.
6. A cathode unit in accordance with Claim 1 or Claim 2, wherein the hole in the disc is in the range 10 - 12 mm.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE7909213-6 | 1979-11-07 | ||
| SE7909213A SE435332B (en) | 1979-11-07 | 1979-11-07 | CATHOD UNIT OF LIGHT |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1150340A true CA1150340A (en) | 1983-07-19 |
Family
ID=20339270
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000364156A Expired CA1150340A (en) | 1979-11-07 | 1980-11-06 | Cathode unit for fluorescent tube |
Country Status (25)
| Country | Link |
|---|---|
| JP (1) | JPH0250582B2 (en) |
| AT (1) | AT377385B (en) |
| AU (1) | AU543221B2 (en) |
| BE (1) | BE886030A (en) |
| BR (1) | BR8008906A (en) |
| CA (1) | CA1150340A (en) |
| CH (1) | CH649653A5 (en) |
| CS (1) | CS250206B2 (en) |
| DE (2) | DE3041548C2 (en) |
| DK (1) | DK158177C (en) |
| ES (1) | ES263202Y (en) |
| FI (1) | FI68928C (en) |
| FR (1) | FR2473785A1 (en) |
| GB (1) | GB2077033B (en) |
| HU (1) | HU181318B (en) |
| IT (1) | IT1134172B (en) |
| MX (1) | MX147322A (en) |
| NO (1) | NO153946C (en) |
| PL (1) | PL132221B1 (en) |
| PT (1) | PT72017B (en) |
| RO (1) | RO81624B (en) |
| SE (1) | SE435332B (en) |
| SU (1) | SU1218936A3 (en) |
| WO (1) | WO1981001344A1 (en) |
| YU (1) | YU39696B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6384534B1 (en) | 1999-12-17 | 2002-05-07 | General Electric Company | Electrode material for fluorescent lamps |
| CN107026069A (en) * | 2015-10-06 | 2017-08-08 | 优志旺电机株式会社 | Short arc discharge lamp |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0555619B1 (en) * | 1992-02-13 | 1996-05-22 | Luminova Aktiebolag | Cathode screen for gas discharge lamps |
| SE515637C2 (en) | 2000-01-24 | 2001-09-17 | Auralight Ab | Security structure for fluorescent lamps |
| US6741023B2 (en) * | 2001-07-10 | 2004-05-25 | Light Sources, Inc. | Fluorescent tanning lamp with improved service life |
| SE524397C2 (en) * | 2002-04-11 | 2004-08-03 | Auralight Int Ab | Cathode unit for fluorescent lamps and method for manufacturing fluorescent lamps |
| US6812639B2 (en) * | 2002-09-13 | 2004-11-02 | Light Sources, Inc. | Germicidal lamp with end of life arc quenching device |
| US6809468B1 (en) | 2002-12-11 | 2004-10-26 | Light Sources, Inc. | Cathode with disintegration shield in a gas discharge lamp |
| DE10334175B4 (en) * | 2003-07-26 | 2006-09-21 | Dei-Anang, Kwesi, Priv.-Doz. Dr.med. | Respirator |
| JP2008204856A (en) * | 2007-02-21 | 2008-09-04 | Nec Lighting Ltd | Thermoionic cathode fluorescent lamp |
| RU2505744C2 (en) * | 2012-03-06 | 2014-01-27 | Государственное научное учреждение Всероссийский научно-исследовательский институт электрификации сельского хозяйства Российской академии сельскохозяйственных наук (ГНУ ВИЭСХ Россельхозакадемии) | Electric lighting system (versions) |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2008066A (en) * | 1933-02-17 | 1935-07-16 | Quarzlampen Gmbh | Gas or vapor discharge tube |
| US2238277A (en) * | 1940-02-09 | 1941-04-15 | Miller Maurice | Combination tube closure and electrode for neon tubes |
| US2725497A (en) * | 1951-04-25 | 1955-11-29 | Westinghouse Electric Corp | Floating grids for fluorescent lamps |
| DE955341C (en) * | 1952-01-13 | 1957-01-03 | Physikalisch Tech Werkstaetten | Gas discharge tubes with a screen enclosing the cathode in a pot-shaped manner |
| FR1110434A (en) * | 1954-08-31 | 1956-02-13 | Hyperion Sa | Improvements to the electrodes of the discharge tubes |
| US2917650A (en) * | 1955-06-29 | 1959-12-15 | Hyperion Sa | Electrode for discharge tubes |
| GB841343A (en) * | 1957-10-09 | 1960-07-13 | Philips Electrical Ind Ltd | Improvements in or relating to low-pressure mercury vapour discharge tubes |
| FR1271505A (en) * | 1959-05-11 | 1961-09-15 | Lampes Sa | Low pressure discharge device |
| US3121184A (en) * | 1960-12-30 | 1964-02-11 | Gen Electric | Discharge lamp with cathode shields |
| NL6514352A (en) * | 1965-11-05 | 1967-05-08 | ||
| US3390297A (en) * | 1966-07-01 | 1968-06-25 | Perkin Elmer Corp | Shield for hollow cathode lamps |
| US3430359A (en) * | 1967-02-09 | 1969-03-04 | Roll O Sheets | Apparatus with heat conductive belt |
| US3623136A (en) * | 1968-05-10 | 1971-11-23 | Hitachi Ltd | Light-source lamp for atomic light-absorption analysis |
-
1979
- 1979-11-07 SE SE7909213A patent/SE435332B/en not_active IP Right Cessation
-
1980
- 1980-11-04 IT IT25764/80A patent/IT1134172B/en active
- 1980-11-04 DE DE3041548A patent/DE3041548C2/en not_active Expired
- 1980-11-04 DE DE19808029380U patent/DE8029380U1/en not_active Expired
- 1980-11-04 PT PT72017A patent/PT72017B/en unknown
- 1980-11-05 BE BE0/202699A patent/BE886030A/en not_active IP Right Cessation
- 1980-11-05 FR FR8023573A patent/FR2473785A1/en active Granted
- 1980-11-06 MX MX184636A patent/MX147322A/en unknown
- 1980-11-06 ES ES1980263202U patent/ES263202Y/en not_active Expired
- 1980-11-06 HU HU801205A patent/HU181318B/en unknown
- 1980-11-06 YU YU2839/80A patent/YU39696B/en unknown
- 1980-11-06 WO PCT/SE1980/000279 patent/WO1981001344A1/en active IP Right Grant
- 1980-11-06 BR BR8008906A patent/BR8008906A/en not_active IP Right Cessation
- 1980-11-06 JP JP55502594A patent/JPH0250582B2/ja not_active Expired - Lifetime
- 1980-11-06 CA CA000364156A patent/CA1150340A/en not_active Expired
- 1980-11-06 AU AU65704/80A patent/AU543221B2/en not_active Expired
- 1980-11-06 GB GB8120702A patent/GB2077033B/en not_active Expired
- 1980-11-06 CH CH8265/80A patent/CH649653A5/en not_active IP Right Cessation
- 1980-11-07 CS CS807548A patent/CS250206B2/en unknown
- 1980-11-07 AT AT0547480A patent/AT377385B/en active
- 1980-11-07 PL PL1980227738A patent/PL132221B1/en unknown
-
1981
- 1981-07-03 DK DK296081A patent/DK158177C/en active
- 1981-07-06 FI FI812128A patent/FI68928C/en not_active IP Right Cessation
- 1981-07-06 NO NO812294A patent/NO153946C/en unknown
- 1981-07-06 SU SU813315649A patent/SU1218936A3/en active
- 1981-07-07 RO RO104806A patent/RO81624B/en unknown
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6384534B1 (en) | 1999-12-17 | 2002-05-07 | General Electric Company | Electrode material for fluorescent lamps |
| CN107026069A (en) * | 2015-10-06 | 2017-08-08 | 优志旺电机株式会社 | Short arc discharge lamp |
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