CA1096603A - Luminescent screen - Google Patents
Luminescent screenInfo
- Publication number
- CA1096603A CA1096603A CA266,422A CA266422A CA1096603A CA 1096603 A CA1096603 A CA 1096603A CA 266422 A CA266422 A CA 266422A CA 1096603 A CA1096603 A CA 1096603A
- Authority
- CA
- Canada
- Prior art keywords
- luminescent
- aluminate
- aluminates
- magnesium
- luminescent screen
- 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
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
- C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
- C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
- C09K11/7766—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals
- C09K11/7774—Aluminates
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Luminescent Compositions (AREA)
- Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
Abstract
ABSTRACT:
Luminescent aluminate of trivalent cerium and of magnesium, which is activated by trivalent terbium of the composition (1/2-x-y)Ce2O3.xLa2O3.yTb2O3.MgO.pAl2O3 where 0 ? x ? 0.20 0.05 ? y ? 0.25 6.25 ? p ? 25, and in which the Mg may be wholly or partly replaced by Zn and/or Me, and the Al to a maximum of 25 mole % by Ga and/or Se.
Luminescent aluminate of trivalent cerium and of magnesium, which is activated by trivalent terbium of the composition (1/2-x-y)Ce2O3.xLa2O3.yTb2O3.MgO.pAl2O3 where 0 ? x ? 0.20 0.05 ? y ? 0.25 6.25 ? p ? 25, and in which the Mg may be wholly or partly replaced by Zn and/or Me, and the Al to a maximum of 25 mole % by Ga and/or Se.
Description
~Q~66~3 PHN 82~0 The invention relates to a luminescent screen provided with a luminescent a:Luminate of trivalent cerium and of magnesium, which aluminate is activated by trivalent terbium. Furthermore the invention relates to a low-pressure mercury vapour discharge lamp provided with such a luminescent screen and to the luminescent aluminate itself.
Our Canadian Patent 1,028,844 which issued on April 4, 1978 discloses a lar~e number of luminescent aluminates and gallates, the host lattices of which are ternary compounds which contain besides aluminium and/or gallium a large positive ion and a small bivalent ion, particularly magnesium. Of the luminescent materials described, the terbium-activated aluminates of cerium and magnesium constitutes a particularly important group.
These aluminates, which appear to have a crystal structure corresponding to that of magnetoplumbite (PbFel2019), emit namely when excited by, for example ultraviolet radiation, in a very efficient manner the characteristic Tb3 20` emmission~ They are therefore used with much advantage in low pressure mercury vapour discharge lamps ~see also our Canadian Patent 1,033,158 which issued on June 20, ` 1978).
The molar ratios of the elements present in ~,~
B
. .................................... :
~66~3 .
said ternary compounds may generally be within wide ranges of ~alues. It has appeared, howevert ~hat in the case of the terbium-activated aluminates of cerium and magnesium, optimum luminescent properties, especially as regards the lumlnous flux, are achieved with materials which satisfy the formula (Ce, Tb) MgAll1019. When preparing these aluminates a deviation is often made, as described in the above-men-tioned Canadian Patent 1,028,844, from the stoichiometry of this optimally luminescent phase and a small excess of A1203 is added in order to obtain a reaction process which proceeds better. When using, for example, 10 mole ~ A1203 in excess the composition of the reaction product may be represented as ~(Ce,Tb)203.
- MgO.6.05 A1203.
- 15 Terbium-activated aluminates of cerium and magnesium are also disclosed in German Patent 2,501,783, which issued to Thorn Electrical Industries on July 24, 1975, in which wide ranges are also indicated for the molar ratios of the composite elements. The compounds described in this place have the crystal structure of -alumina (a structure which i~ strongly related to that of magnetoplumbite~. As optimally luminescent aluminates of cerium and magnesium are mentioned (Ce, Tb)Mgl 25A122035 75 ' ) g2A122036.5; however, no values of the luminous flu~ of these luminescent phases are given.
It is an object of the invention to provide . .
6~3 PHN 8240 improved terbium-actlvated lu~inescent aluminates on the basis of the known (Ce,Tb)MgA:LllOlg-phase with magneto-plumbite structure.
A luminescent screen according to the invention is provided with a luminescent aluminate of trivalent cerium and of magnesium which is activated by trivalent terbium and is characterized in that the aluminate has the composition (~-x-y)ce2o3~xLa2o3 yTb2o3~Mgo pAl2o3 where 0 ~ x ~ 0.20 0.05 ~ y ~ 0.25 6.2 ~ p C 25, and where the Mg may be replaced partly or wholly by Zn and/or Be, and the Al to a maximum of 25 mole % by Ga and/or Sc.
A luminescent screen according to the invention contains a cerium magnesium aluminate in which in known manner (see Canadian Patents l,028,844 and l,033,158 already mentioned above) part of the Ce may be replaced by La and part (maximum 25 mole %) of the Al ma~ be replaced by Ga and/or Sc. Furthermore, it is possible to replace the Mg wholly or partly by Zn and/or Be. Said substitutions affect the luminescent properties of the aluminate only sllghtly and yield no additional advantages.
The luminescent aluminates according to the invention contain a comparativeIy large to a very , .
- - : , , -PHN. 82~0.
6~3 large excess of A12O3 with respect to the stoichiome-trical quantity (p = 5.5). They are obtained by heat-ing to a high temperature, for example a 1200C or higher, a starting mixture of the composite oxides in the specified quantities or of compounds which form these oxides on heating x-ray diffraction analyses of the luminescent aluminates according to the inven-tion display the characteristic pattern of magneto~
plumbite together with the diffraction lines of A1203. -It is consequently assumed that the luminescent phase proper in a luminescent aluminate according to the invention is the stoichiometric ~Ce, Tb)MgA111019 phase. This is also confirmed by the spectral en~rgy distribution of the omitted radiation which, for the aluminates according to the invention, is identical to that of the stoichiometric phase. Actually, the results of x-ray diffraction analyses performed on the aluminates according to the invention are sub-stantially equal to those of similar analyses on mechanical mixtures of the stoichiometric phase with corresponding large quantities of A1203.
It has surprisingly appeared that with the aluminates according to the invention luminous fluxes are o~tained which can be compared with or are even slightly higher than those obtained with the stoi-chiometric phase. Only with very high values of p . ..
~ in the above-mentioned range (6.2 ~ p ~25~ a slight ,.
- . . ~. ... .
PHN. 8~40.
66~3 decrease is observed in the luminous ~lux. This was to~ally unexpected, as 90 ~ar diluting a luminescent phase with an inert material gave rise to considerable losses in the luminous ~lux.
A great advanl:age of the aluminates according to the invention is that they are considerably cheaper than the pure stoichiometric phase. With a value o~ p in the above-mentioned composition equal to 15, for example, a material is obtained which consists for less than 50 weight % o~ the stoichiometric phase and whose luminous flux is Iess than 2% lower than that of the stoichiometric phase. This yields a saving in cost of approximately 50% when a same pow~er weight is used in the luminescent screen. In the aluminates according to the invention the value of p is not chosen to be lower than 6.2 because then the savings obtained would be too small. Values of p which exceed 25 are not used because then too large a loss in luminous flux would occur.
The aluminates according to the invention have the additional advantage that they are obtained in the form of a powder with an average grain diameter, which is smaller than that of the stoichiometric com-pound. This offers a possibility to use lower powder weights in the luminescent screen whilst maintaining the luminous flux. This also means a further economic advantage.
. ' - 6 - ;
:
PHN. ~240.
~,@~66~
The alumina-tes according to the inven-tion appear, when used in the luminescent screen of low-pressure mercury vapour discha~ge lamps to have during the operating life of the lamps a smaller decline of the luminous flux than the stoichiometric compound, which o~
course is very advantageous. An aluminate according to the invention which initially yields, in a lamp, a luminous flux which is a few per cents smaller may already emit a larger luminous flux after 100 operating hours than the stoichiometric compound.
Preference is given to aluminates according to the invention where x = O, 0.15 ~ Y 0~20 and 10 ~ p 15. Namely with these materials the most favourable combinations of cost reduction and high luminous fluxes are obtained.
The invention will now be further explained with reference to a number of embodiments and measure-ments and a drawing.
Starting from the basic materials A1203, MgO, CeO2 and Tb407 materials of the composition / (Cel.33Tbo~67) 03 MgO-pA1103 with respectively p = 7.0; 10.4; 14.2 and 21.1 are made by carefully mixing these basic materials in the required quantities and by heating the mixture obtained twice, in air, each 25 time for 1 hour at 1550C. Each heating operation is followed by cooling in nitrogen. The product thus ob-tained is pulverized and sieved and thereafter heated , ~ .
:, .
~ 3 PHN 8240 for 2 hours at 1200C in a nitrogen current which contains some vol. ~, for example 2 vo:L. %, of hydrogen and which has been passed through water of approximately 15C.
After cooling and pulverizing the product is ready.
In a manner which is known in itself the lumine-scent aluminates thus obtainecl are applied to the luminescent screen of a low-pressure mercury vapour discharge lamp.
Measurements of the luminous flux (in Lm/W) of these lamps at different times during burning of the lamps are summarized in the table which follows herebelow. For comparison the table shows under example (a~ the measure-ments of a known aluminate with a very slight excess of A1203 (p = 6.05 ; not according to the invention; see our Canadian Patent 1,028,844). Also for comparison, under (b) the measuring results are shown which are obtained with lamps provided with a mechanical mixture of the material specified under (a) with 15.05 mol A1203. Prior to mixing the A1203 was submitted to a heat treatment analogous to the heat treatment as used in the preparation described above of the aluminates according to the invention. The material mentioned under (b) contains a total of 21.1 mole A1203 (compare with example 4).
A material of a composition equal to example
Our Canadian Patent 1,028,844 which issued on April 4, 1978 discloses a lar~e number of luminescent aluminates and gallates, the host lattices of which are ternary compounds which contain besides aluminium and/or gallium a large positive ion and a small bivalent ion, particularly magnesium. Of the luminescent materials described, the terbium-activated aluminates of cerium and magnesium constitutes a particularly important group.
These aluminates, which appear to have a crystal structure corresponding to that of magnetoplumbite (PbFel2019), emit namely when excited by, for example ultraviolet radiation, in a very efficient manner the characteristic Tb3 20` emmission~ They are therefore used with much advantage in low pressure mercury vapour discharge lamps ~see also our Canadian Patent 1,033,158 which issued on June 20, ` 1978).
The molar ratios of the elements present in ~,~
B
. .................................... :
~66~3 .
said ternary compounds may generally be within wide ranges of ~alues. It has appeared, howevert ~hat in the case of the terbium-activated aluminates of cerium and magnesium, optimum luminescent properties, especially as regards the lumlnous flux, are achieved with materials which satisfy the formula (Ce, Tb) MgAll1019. When preparing these aluminates a deviation is often made, as described in the above-men-tioned Canadian Patent 1,028,844, from the stoichiometry of this optimally luminescent phase and a small excess of A1203 is added in order to obtain a reaction process which proceeds better. When using, for example, 10 mole ~ A1203 in excess the composition of the reaction product may be represented as ~(Ce,Tb)203.
- MgO.6.05 A1203.
- 15 Terbium-activated aluminates of cerium and magnesium are also disclosed in German Patent 2,501,783, which issued to Thorn Electrical Industries on July 24, 1975, in which wide ranges are also indicated for the molar ratios of the composite elements. The compounds described in this place have the crystal structure of -alumina (a structure which i~ strongly related to that of magnetoplumbite~. As optimally luminescent aluminates of cerium and magnesium are mentioned (Ce, Tb)Mgl 25A122035 75 ' ) g2A122036.5; however, no values of the luminous flu~ of these luminescent phases are given.
It is an object of the invention to provide . .
6~3 PHN 8240 improved terbium-actlvated lu~inescent aluminates on the basis of the known (Ce,Tb)MgA:LllOlg-phase with magneto-plumbite structure.
A luminescent screen according to the invention is provided with a luminescent aluminate of trivalent cerium and of magnesium which is activated by trivalent terbium and is characterized in that the aluminate has the composition (~-x-y)ce2o3~xLa2o3 yTb2o3~Mgo pAl2o3 where 0 ~ x ~ 0.20 0.05 ~ y ~ 0.25 6.2 ~ p C 25, and where the Mg may be replaced partly or wholly by Zn and/or Be, and the Al to a maximum of 25 mole % by Ga and/or Sc.
A luminescent screen according to the invention contains a cerium magnesium aluminate in which in known manner (see Canadian Patents l,028,844 and l,033,158 already mentioned above) part of the Ce may be replaced by La and part (maximum 25 mole %) of the Al ma~ be replaced by Ga and/or Sc. Furthermore, it is possible to replace the Mg wholly or partly by Zn and/or Be. Said substitutions affect the luminescent properties of the aluminate only sllghtly and yield no additional advantages.
The luminescent aluminates according to the invention contain a comparativeIy large to a very , .
- - : , , -PHN. 82~0.
6~3 large excess of A12O3 with respect to the stoichiome-trical quantity (p = 5.5). They are obtained by heat-ing to a high temperature, for example a 1200C or higher, a starting mixture of the composite oxides in the specified quantities or of compounds which form these oxides on heating x-ray diffraction analyses of the luminescent aluminates according to the inven-tion display the characteristic pattern of magneto~
plumbite together with the diffraction lines of A1203. -It is consequently assumed that the luminescent phase proper in a luminescent aluminate according to the invention is the stoichiometric ~Ce, Tb)MgA111019 phase. This is also confirmed by the spectral en~rgy distribution of the omitted radiation which, for the aluminates according to the invention, is identical to that of the stoichiometric phase. Actually, the results of x-ray diffraction analyses performed on the aluminates according to the invention are sub-stantially equal to those of similar analyses on mechanical mixtures of the stoichiometric phase with corresponding large quantities of A1203.
It has surprisingly appeared that with the aluminates according to the invention luminous fluxes are o~tained which can be compared with or are even slightly higher than those obtained with the stoi-chiometric phase. Only with very high values of p . ..
~ in the above-mentioned range (6.2 ~ p ~25~ a slight ,.
- . . ~. ... .
PHN. 8~40.
66~3 decrease is observed in the luminous ~lux. This was to~ally unexpected, as 90 ~ar diluting a luminescent phase with an inert material gave rise to considerable losses in the luminous ~lux.
A great advanl:age of the aluminates according to the invention is that they are considerably cheaper than the pure stoichiometric phase. With a value o~ p in the above-mentioned composition equal to 15, for example, a material is obtained which consists for less than 50 weight % o~ the stoichiometric phase and whose luminous flux is Iess than 2% lower than that of the stoichiometric phase. This yields a saving in cost of approximately 50% when a same pow~er weight is used in the luminescent screen. In the aluminates according to the invention the value of p is not chosen to be lower than 6.2 because then the savings obtained would be too small. Values of p which exceed 25 are not used because then too large a loss in luminous flux would occur.
The aluminates according to the invention have the additional advantage that they are obtained in the form of a powder with an average grain diameter, which is smaller than that of the stoichiometric com-pound. This offers a possibility to use lower powder weights in the luminescent screen whilst maintaining the luminous flux. This also means a further economic advantage.
. ' - 6 - ;
:
PHN. ~240.
~,@~66~
The alumina-tes according to the inven-tion appear, when used in the luminescent screen of low-pressure mercury vapour discha~ge lamps to have during the operating life of the lamps a smaller decline of the luminous flux than the stoichiometric compound, which o~
course is very advantageous. An aluminate according to the invention which initially yields, in a lamp, a luminous flux which is a few per cents smaller may already emit a larger luminous flux after 100 operating hours than the stoichiometric compound.
Preference is given to aluminates according to the invention where x = O, 0.15 ~ Y 0~20 and 10 ~ p 15. Namely with these materials the most favourable combinations of cost reduction and high luminous fluxes are obtained.
The invention will now be further explained with reference to a number of embodiments and measure-ments and a drawing.
Starting from the basic materials A1203, MgO, CeO2 and Tb407 materials of the composition / (Cel.33Tbo~67) 03 MgO-pA1103 with respectively p = 7.0; 10.4; 14.2 and 21.1 are made by carefully mixing these basic materials in the required quantities and by heating the mixture obtained twice, in air, each 25 time for 1 hour at 1550C. Each heating operation is followed by cooling in nitrogen. The product thus ob-tained is pulverized and sieved and thereafter heated , ~ .
:, .
~ 3 PHN 8240 for 2 hours at 1200C in a nitrogen current which contains some vol. ~, for example 2 vo:L. %, of hydrogen and which has been passed through water of approximately 15C.
After cooling and pulverizing the product is ready.
In a manner which is known in itself the lumine-scent aluminates thus obtainecl are applied to the luminescent screen of a low-pressure mercury vapour discharge lamp.
Measurements of the luminous flux (in Lm/W) of these lamps at different times during burning of the lamps are summarized in the table which follows herebelow. For comparison the table shows under example (a~ the measure-ments of a known aluminate with a very slight excess of A1203 (p = 6.05 ; not according to the invention; see our Canadian Patent 1,028,844). Also for comparison, under (b) the measuring results are shown which are obtained with lamps provided with a mechanical mixture of the material specified under (a) with 15.05 mol A1203. Prior to mixing the A1203 was submitted to a heat treatment analogous to the heat treatment as used in the preparation described above of the aluminates according to the invention. The material mentioned under (b) contains a total of 21.1 mole A1203 (compare with example 4).
A material of a composition equal to example
2 of the tab:Le (p = 10.4) is obtained by suspending .
I'l]N 8i'~
I'l]N 8i'~
3 1 o . ~
tlle :requ:i.red q~lalltl-t:~ oI` :E`illely clis~e.rs(?cl l~:L203 ;:rl a so] u ti on o:E` Ce-, Mg-, ~.ri~ ancl, op ti ona:l :l y, I~l.~ni tra te, ereaf`-ter b~r add i.nrr Nl-l~101-l the me l;al llyclroxicles arc percipitated onto -the 1\1203. 'Nle coprec:ipitate ob~
tained is -tllerea:~ter heated in tl~e same 3nan~e:r as descri~ed abov-e. Measurements made on lamps prov:i.c1ed .~ith the 1ulllirlescellt alulllinate thus obtailled are :L:ist-ed under examp1e 5 in the tab~ e.
.. ~
lum:inoll.s :f` 1 ux ... ~ . .__~
E~am- .0 hour 100 1000 ple P . hours hoL1rs .~
~m/l~ 1n % ~ r t .Lm/W ~m/W
~ ........ _ ~ ~_ ~ :
. .. (a) 6,o5109,5 103,5105,3 9717 . 1 7, 109~6 100,2-109,~ 105.1 2 10,11109,2 101~1108,0 102 3 lL~2 107~ 100.7107,0 101,1 Ll 21 ~ 1102~ ~l 101 ,5 . . 100,9 97.0 ~1~) 6,o5 ~91,S 107,585~1~ 77~1 1~ 0 mo1e ~
. , ~ ~ lO~./I108,6 -10!~,7_ L
-- ~ ~ ~ ~._. _ .~..... .
.~ .
:` :
_ 9 . : .
,~
~ : . , , : ~
I'] li~
lo. 1 1.7G
~6~ 3 T]-le dra~ ng shows a low~pressure mercllry vapollr dischalge la~np accordin~: to t:l~e :i:nveIltion. The lalnp com-prises all envelope 1 wi-th electrodes 2 and 3 place(l one at each encZ thereo:r. The inte:rnal sur~ace o:~ the en-velope 1, whic}l is, for exalnp:Le, made o~ glass :i.s coat~
ed Wit}l a luminescent layer 4 whicll contains a ,Lum;.-nescent aluinina-te accorcdin~ tol:the invention. Tlle lu-minescellt al.umiliate, optionally m:ixed wi-tll o-ther ].umi-nescent materia:Ls ma~r be applied to the enve].ope 1 by applying a suspension o~ th.e luminescent mate:rial and nitrocel:Lulose in butyl-acetate to the internal sur-~ace o~ the eIlvelope so -that a thin coating of this suspension is ~ormed. lIerein nitrocellulose serves as a temporary binder. Thereafter the envelope is sub-mit-ted to a tempera-ture treatment which expels -the binder and which results in a proper adhesion o~ -the l~inescont coat.
; . : - 1 0 ~ - ~
tlle :requ:i.red q~lalltl-t:~ oI` :E`illely clis~e.rs(?cl l~:L203 ;:rl a so] u ti on o:E` Ce-, Mg-, ~.ri~ ancl, op ti ona:l :l y, I~l.~ni tra te, ereaf`-ter b~r add i.nrr Nl-l~101-l the me l;al llyclroxicles arc percipitated onto -the 1\1203. 'Nle coprec:ipitate ob~
tained is -tllerea:~ter heated in tl~e same 3nan~e:r as descri~ed abov-e. Measurements made on lamps prov:i.c1ed .~ith the 1ulllirlescellt alulllinate thus obtailled are :L:ist-ed under examp1e 5 in the tab~ e.
.. ~
lum:inoll.s :f` 1 ux ... ~ . .__~
E~am- .0 hour 100 1000 ple P . hours hoL1rs .~
~m/l~ 1n % ~ r t .Lm/W ~m/W
~ ........ _ ~ ~_ ~ :
. .. (a) 6,o5109,5 103,5105,3 9717 . 1 7, 109~6 100,2-109,~ 105.1 2 10,11109,2 101~1108,0 102 3 lL~2 107~ 100.7107,0 101,1 Ll 21 ~ 1102~ ~l 101 ,5 . . 100,9 97.0 ~1~) 6,o5 ~91,S 107,585~1~ 77~1 1~ 0 mo1e ~
. , ~ ~ lO~./I108,6 -10!~,7_ L
-- ~ ~ ~ ~._. _ .~..... .
.~ .
:` :
_ 9 . : .
,~
~ : . , , : ~
I'] li~
lo. 1 1.7G
~6~ 3 T]-le dra~ ng shows a low~pressure mercllry vapollr dischalge la~np accordin~: to t:l~e :i:nveIltion. The lalnp com-prises all envelope 1 wi-th electrodes 2 and 3 place(l one at each encZ thereo:r. The inte:rnal sur~ace o:~ the en-velope 1, whic}l is, for exalnp:Le, made o~ glass :i.s coat~
ed Wit}l a luminescent layer 4 whicll contains a ,Lum;.-nescent aluinina-te accorcdin~ tol:the invention. Tlle lu-minescellt al.umiliate, optionally m:ixed wi-tll o-ther ].umi-nescent materia:Ls ma~r be applied to the enve].ope 1 by applying a suspension o~ th.e luminescent mate:rial and nitrocel:Lulose in butyl-acetate to the internal sur-~ace o~ the eIlvelope so -that a thin coating of this suspension is ~ormed. lIerein nitrocellulose serves as a temporary binder. Thereafter the envelope is sub-mit-ted to a tempera-ture treatment which expels -the binder and which results in a proper adhesion o~ -the l~inescont coat.
; . : - 1 0 ~ - ~
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS
1. A luminescent screen provided with an aluminate of trivalent cerium and of magnesium, which is activated by trivalent terbium, characterized in that the aluminate has the composition (1/2-x-y)Ce2O3.xLa2O3.yTb2O3.MgO.pAl2O3 where 0?x?0.20 0.05?y?0.25 6.2?p?25 and in which the Mg may be wholly or partly replaced by Zn and/or Be and the Al to a maximum of 25 mole % by Ga and/or Sc.
2. A luminescent screen as claimed in Claim 1, characterized in that x = 0 0.15?y?0.20 10?p?15.
3. A luminescent aluminate of trivalent cerium and of magnesium, which is activated by trivalent terbium, characterized in that the aluminate has the composition (1/2-x-y)Ce2O3.xLa2O3.yTb2O3.Mgo.pA12O3, where 0?x?0.20 0.05?y?0.25 6.2?p?25, and in which the Mg may be wholly or partly replaced by Zn and/or Be, and the Al to a maximum of 25 mole % by Ga and/or Sc.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL7513898 | 1975-11-28 | ||
| NLAANVRAGE7513898,A NL178517C (en) | 1975-11-28 | 1975-11-28 | LUMINESCENT SCREEN; LOW-PRESSURE MERCURY DISCHARGE LAMP; METHOD FOR PREPARING A LUMINESCENT ALUMINATE |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1096603A true CA1096603A (en) | 1981-03-03 |
Family
ID=19824938
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA266,422A Expired CA1096603A (en) | 1975-11-28 | 1976-11-24 | Luminescent screen |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS5268084A (en) |
| AR (1) | AR215606A1 (en) |
| AU (1) | AU509091B2 (en) |
| BE (1) | BE848835A (en) |
| CA (1) | CA1096603A (en) |
| DE (1) | DE2652472A1 (en) |
| FR (1) | FR2333037A1 (en) |
| GB (1) | GB1510429A (en) |
| IT (1) | IT1064645B (en) |
| NL (1) | NL178517C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60121099U (en) * | 1984-01-26 | 1985-08-15 | 不二サッシ株式会社 | Wind-stopping material for sliding shoji sliding shoji fittings |
| JPS60141390U (en) * | 1984-03-01 | 1985-09-19 | 不二サッシ株式会社 | Wind-stopping material for sliding shoji sliding shoji fittings |
| JPH0349038Y2 (en) * | 1984-09-19 | 1991-10-18 | ||
| DE102017207796B4 (en) * | 2017-05-09 | 2023-12-14 | Vitesco Technologies GmbH | Method for attaching a permanent magnet in a magnetic pocket of a rotor for an electrical machine |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1500902A (en) * | 1974-01-17 | 1978-02-15 | Thorn Electrical Ind Ltd | Phosphors and their preparation |
-
1975
- 1975-11-28 NL NLAANVRAGE7513898,A patent/NL178517C/en not_active IP Right Cessation
-
1976
- 1976-11-18 DE DE19762652472 patent/DE2652472A1/en not_active Withdrawn
- 1976-11-23 AR AR265579A patent/AR215606A1/en active
- 1976-11-24 CA CA266,422A patent/CA1096603A/en not_active Expired
- 1976-11-25 JP JP51140813A patent/JPS5268084A/en active Granted
- 1976-11-25 AU AU19994/76A patent/AU509091B2/en not_active Expired
- 1976-11-25 GB GB49208/76A patent/GB1510429A/en not_active Expired
- 1976-11-25 IT IT29783/76A patent/IT1064645B/en active
- 1976-11-26 BE BE172781A patent/BE848835A/en not_active IP Right Cessation
- 1976-11-26 FR FR7635734A patent/FR2333037A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| AU509091B2 (en) | 1980-04-17 |
| DE2652472A1 (en) | 1977-06-08 |
| IT1064645B (en) | 1985-02-25 |
| BE848835A (en) | 1977-05-26 |
| JPS5268084A (en) | 1977-06-06 |
| FR2333037B1 (en) | 1981-08-28 |
| JPS5761068B2 (en) | 1982-12-22 |
| FR2333037A1 (en) | 1977-06-24 |
| AR215606A1 (en) | 1979-10-31 |
| AU1999476A (en) | 1978-06-01 |
| GB1510429A (en) | 1978-05-10 |
| NL178517C (en) | 1986-04-01 |
| NL7513898A (en) | 1977-06-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |