GB1599771A - Fluorescent lamps - Google Patents
Fluorescent lamps Download PDFInfo
- Publication number
- GB1599771A GB1599771A GB305578A GB305578A GB1599771A GB 1599771 A GB1599771 A GB 1599771A GB 305578 A GB305578 A GB 305578A GB 305578 A GB305578 A GB 305578A GB 1599771 A GB1599771 A GB 1599771A
- Authority
- GB
- United Kingdom
- Prior art keywords
- phosphor
- color
- combination
- halophosphate
- strontium
- 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
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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
- C09K11/70—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing phosphorus
- C09K11/72—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing phosphorus also containing halogen, e.g. halophosphates
- C09K11/73—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing phosphorus also containing halogen, e.g. halophosphates also containing alkaline earth metals
-
- 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
- C09K11/74—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing arsenic, antimony or bismuth
- C09K11/75—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing arsenic, antimony or bismuth containing antimony
- C09K11/76—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing arsenic, antimony or bismuth containing antimony also containing phosphorus and halogen, e.g. halophosphates
-
- 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
- C09K11/7783—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals one of which being europium
- C09K11/7784—Chalcogenides
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J61/00—Gas-discharge or vapour-discharge lamps
- H01J61/02—Details
- H01J61/38—Devices for influencing the colour or wavelength of the light
- H01J61/42—Devices for influencing the colour or wavelength of the light by transforming the wavelength of the light by luminescence
- H01J61/44—Devices characterised by the luminescent material
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Vessels And Coating Films For Discharge Lamps (AREA)
- Luminescent Compositions (AREA)
Description
(54) IMPROVEMENTS IN FLUORESCENT LAMPS
(71) We, GENERAL ELECTRIC COMPANY, a corporation organized and existing under the laws of the State of New York, United States of America, of 1 River Road,
Schenectady 12345, State of New York, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:
This invention relates generally to fluorescent lamps and in particular to a low-pressure mercury vapor discharge lamp having a particular type phosphor coating to emit white light when excited by the ultraviolet radiation generated from the mercury vapor discharge.
More particularly. the present type lamp construction is intended for general illumination at a color temperature in the range 2,700 K - 6,500 K with a satisfactory color rendition and at higher emission efficiency than conventional deluxe-type fluorescent lamps.
The use of several luminescent materials in combination to produce a predetermined overall spectral energy distribution is well-known. It is also well-known to employ such material combinations as a blended mixture or as a plurality of two or more layers in which one layer generally further comprises a blend of the individual phosphors. Particularly well-known phosphor blends in the form of a single layer phosphor coating to produce white color emission include two component mixtures for deluxe cool-white and deluxe warm-white. These already well-known two component phosphor mixtures generally employ a manganese-activated or antimony-activated strontium haloapatite phosphor constituent including various combinations thereof.Conventional deluxe-type fluorescent lamps represent a compromise between luminous efficiency (lumen output per watt input) and color rendition since better color rendition is usually achieved with a reduction of as much as 35 percent or more in luminous efficiency. A satisfactory color rendition for deluxe-type fluorescent lamps is approximately 80 or more as measured by the generally accepted C.I.E. color rendering index. The color temperature of the emission in these lamps is also fixed at around 3,000 K for the warm-white deluxe lamp, around 3.500 K for the standard white deluxe lamp around 4,2000K for the cool-white deluxe lamp, and around 6,500 K for the daylight deluxe lamp. as measured by the C.I.E. chromaticity x and y values.
A relatively recent fluorescent lamp development employs various rare earth oxide phosphors exhibiting higher luminous efficiency than the conventional phosphors to increase the overall efficiency of the phosphor combination. A rare earth oxide phosphor being employed in this manner is generally blended with two or more different phosphor materials to provide efficient composite emission. In a different known embodiment, the relatively expensive rare earth oxide phosphor material is employed as a separate top layer overlying a phosphor blend layer of less expensive phosphors to increase the absorption of ultraviolet radiation by the expensive material and thereby increase the composite emission.Such a combination permits accomplishment of a predetermined spectral energy distribution utilizing less rare earth oxide phosphor material than would be the case if a single phosphor layer of the blended mixture were employed.
The present invention is a modification or improvement of the invention described and claimed in Patent Specification No. 1556472. This specification claims a fluorescent lamp having a tubular shaped lamp glass envelope. and electrode structure at each end of said glass envelope, a mercury and inert gas filling within said glass envelope, and a phosphor coating on the interior surface of said glass envelope, the phosphor being a combination of a strontium-haloapatite phosphor with europium-activated yttrium oxide phosphor.
The present invention provides a fluorescent lamp which includes a tubular shaped glass envelope, an electrode structure at each end of said glass envelope, a mercury and inert gas filling within said glass envelope, and a phosphor admixture coating on the interior surface of said glass envelope, wherein the phosphor admixture comprises a two phosphor combination of strontium haloapatite phosphor with europium-activated yttrium oxide phosphor, and a third phosphor having a visible emission response similar to the composite emission response of said two phosphor combination, said two phosphor combination consisting of 68-85 weight percent of the strontium haloapatite phosphor, the haloapatite phosphor having the general formula: Srl x-ySbxMny (PO4)6 .A2 wherein A is F or Cl or a combination thereof, x is from 0.04-0.15, and y is from 0.01-0.42, or being a strontium green halophosphate phosphor of the formula: SrR.71Sbo,,52Mno.l7 (PO4)6 0.93(SrF2), a strontium yellow halophosphate phosphor of the formula: Sr8 s6sb( (}3sMn() 33 (P04)6 0.93(SrF2), a strotium blue halophosphate phosphor of the formula: Sr8,g8Sb(,,068MnO,(,ll (PO4)6 0.92(SrF2) or a strontium blue-green halophosphate phosphor of the formula: Sr8 8sSb(,,(,62Mn(, (PO4)6 0.94(SrF2), and 32-15 weight percent of the europium-activated yttrium oxide phosphor, which phosphor combination produces a composite emission at a colour temperature in the range 2,7000K-6,5000K.
As is shown in Patent Specification No. 1556472, the combination of two different phosphor materials attempts to achieve improved luminous efficiency at comparable colour rendition in a deluxe-type fluorescent lamp. More particularly, it has been found that a combination of a strontium haloapatite phosphor with europium-activated yttrium oxide phosphor produces the desired emission at a colour temperature range from 2,700K to 6,500K with both a satisfactory color rendition and higher luminous efficiency than can be obtained with conventional phosphor blends.Useful strontium haloapatite phosphors include strontium blue halophosphate phosphors which are antimony and manganese activated, strontium green halophosphate phosphors coactivated with antimony and manganese and strontium yellow halophosphate phosphors activated with antimony and manganese and which contains a still greater manganese acivator level. A typical phosphor material can be prepared in conventional fashion by firing a mixture of SrH PO4, SrCO3, SrF2, MnCO3, and Sb203 from four to six hours at 1,1000C.
Useful europium-activated yttrium oxide phosphors in the practice of the present invention are also well known. As will be further described in connection with the following preferred embodiments, the selection of particular phosphor material constituents and the proportion of these phosphor constituents in a blended mixture is accomplished in a specific manner from the predetermined visible spectral energy distribution desired as measured by the C.I.E. chromaticity values.
The relative proportions of the individual phosphor constituents in a blended mixture of the present two phosphor combination are maintained at weight ratios having 68-85 weight percent of the strontium haloapatite phosphor and 32-15 weight percent of the europium-activated yttrium oxide phosphor. As will also be further described hereinafter, a blended phosphor mixture contains said phosphor combination at the specified weight ratios and further includes a third phosphor constituent exhibiting a visible emission response comparable to the composite visible emission response of said phosphor combination and produces the same desired results at lower phosphor costs. Such ternary phosphor mixture utilizes a lesser weight proportion of the relatively expensive europiumactivated yttrium oxide phosphor constituent bv replacing a part of the two phosphor combination with another phosphor having a visible emission response similar to the composite emission response of the phosphor combination without appreciably sacrificing luminous efficiency compared with a binary mixture utilizing only said phosphor combination. The particular class of phosphors which can be admixed with the present phosphor combination in this manner may be selected from conventional calcium halophosphate phosphors exhibiting an emission response satisfying the chromaticity x and y values for deluxe-type fluorescent lamps.A useful phosphor in a cool-white deluxe lamp can have the batch formula: Ca869 Sb.185 Mn18 Cd.0972 (PO4)6 (CaF2).89 C1.378 A useful phosphor in a standard white lamp can have the batch formula: Caress Sub.185 Mn.252 Cd.0972 (to4)6 (CaF2).882 C1.379 A useful phosphor in a warm-white deluxe lamp can have the batch formula:: Cay.59 Sub 196 My 342 Cd.0972 (PO4)6 (CaF2).864 Cl.438
A typical phosphor admixture which can be used in a daylight deluxe lamp contains approximately 51 percent by weight of the above defined phosphor combination used in a standard white deluxe lamp with approximately 49 percent by weight of a blue halophosphate having the batch formula: Ca8 81 Sub.082 Cd.0972 (PO4)E (CaF2).95 Illustrative examples for a ternary admixture utilizing various proportions of the particular phosphor additive above identified for use in a standard white deluxe lamp are hereinafter provided in the description of the preferred embodiments.
The present invention will be further described by way of example only with reference to the accompanying drawings, in which
Figure 1 is a perspective view partially broken away of a fluorescent lamp construction in accordance with the present invention;
Figure 2 is a visible emission curve for a blended phosphor mixture in accordance with the present invention:
Figure 3 is a C.I.E. chromaticity diagram including the black body locus line with corresponding color temperatures indicated thereon for various deluxe-type fluorescent lamps; and
Figure 4 is a lumen output graph for a different blended phosphor mixture of the present invention
The present invention is a modification of or an improved in the invention described in patent specification no. 1556472. To show the modification or improvement, a two phosphor component combination will first be described.
The two phosphor combination herein employed utilizes one phosphor constituent emitting relatively broad band emissions in the lower spectral region from approximately 4.500 Angstroms to 5,900 Angstroms along with a specific rare earth oxide phosphor constituent exhibiting narrow band emission in the spectral energy region from approximately 6,000 Angstroms to about 6,150 Angstroms for higher emission efficiency and satisfactory color rendition at the desired color temperature. By varying the weight ratio of these phosphor constituents in the blended mixture as hereinafter described in greater detail, it becomes possible to achieve the same approximate color temperature that is emitted by conventional deluxe-type fluorescent lamps.The improvement in composite emission results from the relatively higher emission efficiency of the rare earth oxide phosphor compared with that for the tin-activated orthophosphate phosphor now used in said conventional lamps and the two phosphor combination has also been found to provide this benefit with no appreciable decrease in lamp maintenance.
Referring to Figure 1, there is shown a fluorescent lamp 1 comprising an elongated soda-lime silicate glass bulb 2 with a circular cross section. The discharge assembly in said lamp has the usual electrode structure 3 at each end supported by in-lead wires 4 and 5 which extend through a glass press seal 6 in a mount stem 7 to the contacts of a base 8 affixed at opposite ends of the lamp. The discharge-sustaining filling in the sealed glass tube is an inert gas such as argon or a mixture of argon and other gases at a low pressure in combination with a small quantity of mercury to provide the low vapor pressure manner of lamp operation. The inner surface of the glass bulb is provided with a phosphor coating 9 which is applied extending substantially the full length of the bulb and around the bulb circumferential inner wall.
Various 40-WT12 lamps were constructed for comparison with conventional deluxe-type fluorescent lamps now utilizing strontium blue halophosphate or strontium green halophosphate with tin-activated strontium orthophosphate in approximately equal weight proportions. The conventional deluxe white lamps exhibited approximately 2,100 lumens value at 100 hours with a color temperature within the color oval shown in Figure 3 while the two phosphor combination utilizing an approximate 80 parts strontium green halophosphate with 20 parts europium-activated yttrium oxide in the blended mixture achieved 2,750 lumens output at approximately the same color temperature. The lamps further exhibited a 5-8 percent lumen depreciation after 1,000 hours of burning which is comparable to the maintenance performance of the conventional deluxe-type fluorescent lamps tested.
The particular emission spectrum for the above illustrated lamp construction is shown in
Figure 2. It can be noted from said visible emission curve that broad band emission over the spectral region extending from approximately 4,500 Angstroms to 5,900 Angstroms wave length is attributable to the proportion of strontium green halophosphate phosphor in the blended mixture having a chemical composition which can be represented by the structural formula:
Sr8.71 Sb.(f52 Mn,l7 (PO4)6 .0.93(SrF2)
The portion of said emission curve extending from approximately 5,800 Angstroms to 6,200 Angstroms wave length is attributable to the proportion of rare earth oxide phosphor in the blended mixture, said phosphor having a chemical composition which can also be represented by the structural formula: Eu3+:Y203.A color-rendering index value of 82 was obtained for said lamp construction as measured by the generally accepted C.I.E. method.
The x and y chromaticity values for said lamp construction in accordance with a further well-known C.I.E. method were found to be x = 0.404 and y = 0.395. Said chromaticity values lie within the same color oval shown in Figure 3 for conventional deluxe white lamps.
Comparable results are obtained with a different phosphor combination to provide a warm-white deluxe color emission having a color point within or adjacent the color oval shown in Figure 3 for conventional deluxe warm-white lamps. Specifically, a high efficiency strontium yellow halophosphate phosphor having the structural formula: SrgS6 Sub.035 Mn33 (PO4)6 0.93(SrF2) is blended with europium-activated yttrium oxide in the proportions to provide a desired color point adjacent the black body locus line. Said particular phosphor blend comprised approximately 83 parts of the strontium yellow halophosphate phosphor and 17 parts of the europium-activated yttrium oxide phosphor which resulted in a 100 hour lumen output value of 2,900 lumens when tested in 40-WT12 lamps.The x and y chromaticity values achieved with said mixture were x = 0.445 and y = 0.415 which corresponded to a color point adjacent the desired color oval.
A cool-white deluxe color emission can be obtained having a higher efficiency than with conventional deluxe-type phosphor blends. More particularly, a mixture containing 80 parts of a strontium blue-green halophosphate phosphor coactivated with antimony and manganese having the structural formula: Sir, 85 Sub.061 Mn,()5 (PO4)6 0.94(SrF2) and 20 parts europium-activated yttrium oxide phosphor provided composite emission within the standard color oval shown in Figure 3 for conventional deluxe cool-white lamps.
The x and y chromaticity values for said mixture measured x = 0.374 and y = 0.364 utilizing the same C.I.E. method of measurement. A 40-WT12 type fluorescent lamp using said phosphor blend produced a 100 hour lumen output value of approximately 2.650 lumens along with a 90 color rendering index value.
A still further example for a daylight deluxe fluorescent lamp is provided having a composite emission color point within or adjacent the color oval shown in Figure 3 for conventional deluxe daylight lamps. Accordingly, 84 parts strontium blue halophosphate phosphor having the structural formula: Srg g8 Sb (,g Mn (31 l (PO4)6 0.92(SrF2) were blended with 16 parts of the europium-activated yttrium oxide phosphor and the 40-WT12 lamps coated with said blend exhibited a 100 hour lumen output value of 2,650 lumens with a 93 C.I.E. color rendering index value. The x and y chromaticity values obtained by the same C.I.E. method of measurement previously employed were x = .313 and y = .346.
An explanation of the manner in which the desired emission color point is obtained with the present phosphor combination is also shown in Figure 3. The straight solid line appearing on said graph represents the color points obtained by compositional variation of the strontiumhaloapatite phosphor within the general range previously given. More particularly, one point illustrated on said straight line is the color point exhibited by the strontium blue halophosphate phosphor mentioned above while the second point illustrated on said straight line represents the color point exhibited by the hereinbefore disclosed strontium green halophosphate phosphor.The color point for the europium-activated yttrium oxide phosphor is also shown on said graph which permits a second straight dash line to be drawn between said color point and the particular point on the solid line representing the color point of the halophosphate phosphor. It will be noted for the particular illustration shown wherein the strontium green halophosphate phosphor is blended with said Y203:Eu phosphor that the dash line intersects the standard color oval for conventional deluxe white lamps. Such intersection demonstrates that color points within a particular color oval can be obtained by varying the weight proportion of the two component phosphor materials.In like manner, it will be evident that comparable color emission characteristics within the color ovals shown for deluxe warm-white, deluxe cool-white, and deluxe daylight lamps are obtained by varying the weight proportions in the two phosphor combination and utilizing other strontiumhaloapatite phosphor materials as hereinbefore disclosed.
To improve or modify the performance of the two component phosphor combination, a part of the combination is replaced by a third phosphor as a blended admixture. Typical ternary phosphor admixtures for a standard white deluxe lamp can have various weight proportions of the Ca65 Sb.185 Mn 2S2 Cud 0972 (PO4)6 (CaF2).882 C1.379 phosphor blended with a particular phosphor combination of the present invention utilizing 75 parts of the strontium green halophosphate phosphor and 25 parts of the europium-activated yttrium oxide phosphor.Accordingly, a 40-WT12 type fluorescent lamp was constructed utilizing said ternary phosphor mixtures wherein said mixtures contained 30-70 percent by weight of the calcium halophosphate phosphor constituent with the balance consisting of the designated phosphor combination. All of said ternary phosphor mixtures exhibited a color temperature within the applicable color oval shown in Figure 3 along with color-rendering indices ranging between 66-74 and which can be still acceptable C.I.E. values for deluxe type lamps. The corresponding 0 hour total lumen values measured upon said lamps is shown in Figure 4. The increased lumen output of said lamps with increasing proportions of the calcium halophosphate constituent as shown is accompanied by decrease in the C.I.E.
coloring rendering index values to the extent above specified. It is also expected that comparable results can be obtained for admixtures utilizing the remaining calcium halophosphate phosphor additives previously disclosed. Accordingly, blended phosphor mixtures utilizing the present phosphor combination can contain up to 50 percent or more by weight of said calcium halophosphate phosphor constituents and still provide deluxe color rendition at higher lumen output and reduced cost.
From the above preferred embodiments it is also evident that a particular three component phosphor combination has been provided which achieves significantly more light output than with current deluxe phosphor blends in fluorescent lamps.
WHAT WE CLAIM IS:
1. A fluorescent lamp which includes a tubular shaped glass envelope, an electrode structure at each end of said glass envelope, a mercury and inert gas filling within said glass envelope. and a phosphor admixture coating on the interior surface of said glass envelope, wherein the phosphor admixture comprises a two phosphor combination of strontium haloapatite phosphor with europium-activated yttrium oxide phosphor, and a third phosphor having a visible emission response similar to the composite emission response of said two phospor combination, said two phosphor combination consisting of 68-85 weight percent of the strontium haloapatite phosphor, the haloapatite phosphor having the general formula: : Sr(, x ySbxMn (PO4)6 A2 A2 wherein A is F or Cl or a combination thereof, x is from 0.04-0.15, and y is from 0.01-0.42, or being a strontium green halophosphate phosphor of the formula: Srx 7lsb() (s2Mn( l7 (PO4)6 0.93(SrF2).
a strontium yellow halophosphate phosphor of the formula: Srx 56Sb(, (,35Mn(,33 (PO4)6 0.93(SrF2),
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (6)
1. A fluorescent lamp which includes a tubular shaped glass envelope, an electrode structure at each end of said glass envelope, a mercury and inert gas filling within said glass envelope. and a phosphor admixture coating on the interior surface of said glass envelope, wherein the phosphor admixture comprises a two phosphor combination of strontium haloapatite phosphor with europium-activated yttrium oxide phosphor, and a third phosphor having a visible emission response similar to the composite emission response of said two phospor combination, said two phosphor combination consisting of 68-85 weight percent of the strontium haloapatite phosphor, the haloapatite phosphor having the general formula:: Sr(, x ySbxMn (PO4)6 A2 A2 wherein A is F or Cl or a combination thereof, x is from 0.04-0.15, and y is from 0.01-0.42, or being a strontium green halophosphate phosphor of the formula: Srx 7lsb() (s2Mn( l7 (PO4)6 0.93(SrF2).
a strontium yellow halophosphate phosphor of the formula: Srx 56Sb(, (,35Mn(,33 (PO4)6 0.93(SrF2),
a strontium blue halophosphate phosphor of the formula:
Sr8.88Sb0.068Mn0.011 (PO4)6 0.92(SrF2) or a strontium blue-green halophosphate phosphor of the formula:
Sr8,85Sb0.62Mn0.05 (PO4)6 0.94(SrF2).
and 32-15 weight percent of the europium-activated yttrium oxide phosphor, which phosphor combination produces a composite emission at a colour temperature in the range of 2,7000K-6,5000K.
2. A fluorescent lamp as claimed in Claim 1 wherein the third phosphor is:
Ca8.69Sb0.185Mn0.18Cd0.0972 (PO4)6 (CaF2)0.89Cl0.378
3. A fluorescent lamp as claimed in Claim 1 wherein the third phosphor is: Ca8.65Sbo185Mnoz52Cd0.0972 (P04)6 (CaF2)0.882Cl0.379
4. A fluorescent lamp as claimed in Claim 1 wherein the third phosphor is:
Ca8.59Sb0,196Mn0,342Cd0.0972 (PO4)6 (CaF2)0.864Cl0438
5. A fluorescent lamp as claimed in Claim 1 wherein the third phosphor is:
Ca8.81Sb0.082Cd0.0972 (PO4)6 (CaF2)0.95
6. A fluorescent lamp as claimed in Claim 1 substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/763,442 US4079287A (en) | 1975-09-25 | 1977-01-28 | Fluorescent lamp construction utilizing a mixture of two phosphor materials |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1599771A true GB1599771A (en) | 1981-10-07 |
Family
ID=25067846
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB305578A Expired GB1599771A (en) | 1977-01-28 | 1978-01-25 | Fluorescent lamps |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5416870A (en) |
| BE (1) | BE863273A (en) |
| BR (1) | BR7800544A (en) |
| DE (1) | DE2803448C2 (en) |
| FR (2) | FR2379160A1 (en) |
| GB (1) | GB1599771A (en) |
| MX (1) | MX147966A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1394864A1 (en) * | 2001-04-20 | 2004-03-03 | Nichia Corporation | Light emitting device |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2081497A (en) * | 1980-07-31 | 1982-02-17 | Gen Electric | Fluorescent lamp construction utilizing a mixture of two phosphor materials |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2488733A (en) * | 1942-06-17 | 1949-11-22 | Gen Electric | Alkaline earth halophosphate phosphors |
| US3400090A (en) * | 1964-11-09 | 1968-09-03 | Grace W R & Co | Sealing compositions comprising halogenated butyl rubber, drying oil and liquid polyiisobutylene |
| US3301791A (en) * | 1965-04-30 | 1967-01-31 | Du Pont | Red luminescent composition product and process |
| US3602758A (en) * | 1969-06-20 | 1971-08-31 | Westinghouse Electric Corp | Phosphor blend lamps which reduce the proportions of the costlier phosphors |
| US3602757A (en) * | 1969-06-20 | 1971-08-31 | Westinghouse Electric Corp | Multiple-luminescent layer improved lumen maintenance combination |
| DE2128065C2 (en) * | 1970-12-10 | 1983-08-18 | Westinghouse Electric Corp., 15222 Pittsburgh, Pa. | Phosphor layer for an electrical light source for generating white light and use of this phosphor layer |
| NL165605C (en) * | 1974-03-15 | 1981-04-15 | Philips Nv | ELECTRIC GAS DISCHARGE LAMP. |
| CH610705B (en) * | 1975-09-12 | Ebauchesfabrik Eta Ag | DEVICE FOR ATTACHING A DIAL TO A WORK PLATE OF A WATCH. | |
| JPS5241484A (en) * | 1975-09-25 | 1977-03-31 | Gen Electric | Fluorescent lamp structure using two kinds of phospher |
-
1978
- 1978-01-20 FR FR7801587A patent/FR2379160A1/en active Granted
- 1978-01-20 FR FR7801588A patent/FR2379161A2/en active Granted
- 1978-01-24 BE BE184605A patent/BE863273A/en not_active IP Right Cessation
- 1978-01-25 GB GB305578A patent/GB1599771A/en not_active Expired
- 1978-01-27 MX MX17222178A patent/MX147966A/en unknown
- 1978-01-27 DE DE19782803448 patent/DE2803448C2/en not_active Expired
- 1978-01-27 BR BR7800544A patent/BR7800544A/en unknown
- 1978-02-09 JP JP1303078A patent/JPS5416870A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1394864A1 (en) * | 2001-04-20 | 2004-03-03 | Nichia Corporation | Light emitting device |
| EP1394864A4 (en) * | 2001-04-20 | 2010-09-29 | Nichia Corp | Light emitting device |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2803448C2 (en) | 1983-08-04 |
| DE2803448A1 (en) | 1978-08-03 |
| FR2379160B1 (en) | 1982-01-29 |
| FR2379161A2 (en) | 1978-08-25 |
| FR2379160A1 (en) | 1978-08-25 |
| FR2379161B2 (en) | 1982-02-05 |
| JPS5416870A (en) | 1979-02-07 |
| BE863273A (en) | 1978-07-24 |
| BR7800544A (en) | 1978-10-03 |
| MX147966A (en) | 1983-02-17 |
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