WO1994029403A1 - Luminescent material - Google Patents

Luminescent material Download PDF

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Publication number
WO1994029403A1
WO1994029403A1 PCT/AU1993/000276 AU9300276W WO9429403A1 WO 1994029403 A1 WO1994029403 A1 WO 1994029403A1 AU 9300276 W AU9300276 W AU 9300276W WO 9429403 A1 WO9429403 A1 WO 9429403A1
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WO
WIPO (PCT)
Prior art keywords
oxide
composition according
luminescent composition
activating agent
luminescent
Prior art date
Application number
PCT/AU1993/000276
Other languages
French (fr)
Inventor
Desmond Willoughby Kell
Original Assignee
Mickellsun Pty. Ltd.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to AU31166/93A priority Critical patent/AU3116693A/en
Priority claimed from AU31166/93A external-priority patent/AU3116693A/en
Application filed by Mickellsun Pty. Ltd. filed Critical Mickellsun Pty. Ltd.
Priority to PCT/AU1993/000276 priority patent/WO1994029403A1/en
Priority to CN93108022.3A priority patent/CN1097454A/en
Publication of WO1994029403A1 publication Critical patent/WO1994029403A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/38—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
    • 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
    • C09K11/7777—Phosphates
    • 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
    • C09K11/7777—Phosphates
    • C09K11/7778—Phosphates with 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
    • C09K11/77—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
    • C09K11/7777—Phosphates
    • C09K11/7778—Phosphates with alkaline earth metals
    • C09K11/7779—Phosphates with alkaline earth metals with halogens
    • 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
    • C09K11/778—Borates
    • 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
    • C09K11/7795—Phosphates
    • 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
    • C09K11/7795—Phosphates
    • C09K11/7796—Phosphates with 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
    • C09K11/77—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
    • C09K11/7797—Borates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/18—Luminescent screens
    • H01J29/20—Luminescent screens characterised by the luminescent material

Definitions

  • the present invention relates to luminescent materials and to articles coated with such materials.
  • Discharge lamps such as mercury vapour discharge lamps are widely used for general illumination purposes because of their efficient conversion of electrical energy to radiant energy as compared with the standard incandescent lamp.
  • a luminescent composition including the reaction product of an yttrium-silicon-phosphorus phosphor; and an activating agent selected from the group consisting of lanthanum, cerium, terbium and europium oxide and mixtures thereof.
  • the phosphor is activated by a mixture of three or more of said oxides, for example a mixture of lanthanum, cerium, terbium and europium oxides.
  • the activating agent further includes strontium oxide.
  • the luminescent composition according to the present invention may be distinguished from prior art luminescent materials in the use of yttrium-silicon- phosphorus activated phosphors in place of the conventional aluminate or gallate phosphors.
  • conventional aluminate phosphors known in the prior art form an aluminium oxide lattice with various elements positioned within this structure.
  • the luminescent material of the present invention forms a silicone oxide lattice with various elements, preferably including europium, which act as activating agents positioned within the structure - these combinations of activating agents form tri-colour mixes with specific spectral emmissions.
  • the use of a yttrium-silicon-phosphorus phosphor may reduce the cost of the luminescent material and may provide increased useful life span and luminosity.
  • the luminescent material may exhibit substantially no reductions in luminosity over time. Luminosity may in fact increase over time.
  • the silicon source used may be selected from silicic acid, a silicon oxide such as silicon dioxide (e.g. silica), or silicon oxalate. Silicon oxalate is preferred.
  • the quantity of silicon preferred in the final material, expressed in the form of its oxide, is preferably within the range of approximately 10 to 50% by weight, more preferably 10 to 35% by weight, of the total weight of the material.
  • a range of phosphorus compounds may be utilised in the preparation of the luminescent composition, extending from oxides such as phosphorus pentoxide, through the acids such as orthophosphorous acid, halides such as phosphorus trichloride, oxyhalides such as phosphorus oxychloride, and the like.
  • a preferred phosphorus compound is phosphorus pentoxide.
  • the phosphorus will be present, in the form of its oxide, in an amount of from approximately 1 to 20% by weight, more preferably 1 to 10% by weight, based on the total weight of the material.
  • the yttrium source used may be yttrium oxide, preferably in an amount of from approximately 20 to 60% by weight of the total weight of the material.
  • the lanthanides may generally be provided in the hydride, oxide, hydroxide or halide form.
  • the mixture may be a complex of two or more of such lanthanides, a mixture of individual lanthanides, or a mixture of one or more complexes with one or more individual compounds of such lanthanides.
  • the lanthanides will be present in the form of their trivalent oxides, viz M-,0- where M is a lanthanide ion, and will comprise a mixture of the abovementioned individual lanthanides.
  • the lanthanides may be present in the luminescent composition, in amounts of approximately 1 to 36% by weight, more preferably 9 to 36% by weight.
  • the individual lanthanides are preferably present in the following amounts:
  • strontium may be provided in the form of its oxide, halide, nitrate, acid, oxyhalide, or the like. Strontium may be present in amounts of approximately 5 to 15% by weight of the total weight of the luminescent material in its oxide form. It has been found that the inclusion of strontium may increase the correlated colour temperature (CCT) of the material. Minor additives can be included to give special effects, or may be naturally present as impurities. The most notable of these include compounds, ions, radicals and other chemical entities of the following elements: aluminium, calcium, manganese, lead, barium, bismuth, boron and chlorine.
  • the luminescent material may be prepared by known methods such as by solid-state reaction at elevated temperature.
  • a process for the preparation of a luminscent composition which includes providing a source of yttrium, silicon and phosphorus; and an activating agent selected from the group consisting of lanthanum, cerium, terbium and europium oxide and mixtures thereof; mixing the yttrium, silicon, phosphorus and activating agent; and firing the mixture at elevated temperature.
  • the product so formed may have a Hyundaious structure.
  • the activating agent is preferably a mixture of lanthanum, cerium, terbium and europium oxides.
  • a mixture of the components in the required stoichiometric amounts may be heated to approximately 1200°C to 1750°C, preferably 1458°C to 1700°C, until a sacrificeous substance is formed.
  • the product may be subjected to a size reduction step.
  • the substance may be cooled, ground and sieved.
  • the particulate material so formed may for example have a particle size within the range of approximately 1-30 microns.
  • the particulate material may be mixed with a bonding agent such as butyl acetate, xylene, hydroxy ethyl cellulose or water, to form a slurry for coating the inner surface of a low pressure discharge lamp.
  • Coating of the discharge lamp may also be carried out by known methods.
  • the lamp is initially, internally washed, dried and cooled prior to coating, for example, by an "up flush” method.
  • the "up flush” method comprises pressurising a slurry of the coating material with an inert gas such as argon to force the coating material to rise up the inside of the lamp.
  • a coating at least 60 microns is thus formed on the inner surface of the lamp, and the lamp is drained, cooled and then dried with hot air.
  • a gas braking lehr may then be used for sintering the coating material and removing the coating from the ends of the lamp.
  • the luminescent material according to the invention may be used advantageously in discharge lamps, for example low pressure mercury vapour discharge lamps for general illumination purposes and exhibit wide spectral distribution as illustrated in the accompanying examples.
  • discharge lamps for example low pressure mercury vapour discharge lamps for general illumination purposes and exhibit wide spectral distribution as illustrated in the accompanying examples.
  • the present invention will now be more fully described with reference to the accompanying examples and to the accompanying drawings which are graphs of the spectral energy distribution of emitted radiation. It should be understood, however, that the description following is illustrative only and should not be taken in any way as a restriction on the generality of the invention described above.
  • This mix imparts a colour correlated temperature which has more of the red spectrum.
  • a mixture was made of the following ingredients which were admixed in the stated amounts: 16% wgt silicon oxalate, 15% wgt lanthanum oxide, 6% wgt cerium oxalate, 3% wgt terbium oxide, 27% wgt yttrium oxide, 2% wgt europium oxide, 9% wgt strontium carbonate and 7% wgt phosphorus pentoxide.
  • Impurities in the admixture mainly consisted of ⁇ 1% wgt aluminium oxide, ⁇ 1% wgt calcium carbonate, ⁇ 1% wgt magnesium oxide, ⁇ 1% manganese oxide, ⁇ 1% wgt barium chloride, ⁇ 1% wgt bismuth carbonate and ⁇ 1% wgt boron oxide.
  • the mixture was heated in a furnace at 1500°C until a glacious mass formed.
  • the product was then cooled and ground, and a particulate sieved to approximately 2-30 microns.
  • the mixture was coated on a conventional compact low pressure mercury discharge lamp by a conventional coating technique, and a Spectral Energy Test conducted.
  • the correlated colour temperature was 5,500°K as depicted in Figure 1.
  • a mixture was made of the following ingredients where were admixed and heated in the stated amounts in the same manner as in Example 1: 29% wgt silicon oxalate, 9% wgt lanthanum oxide, 4% wgt cerium oxide, 2% wgt terbium oxide, 49% wgt yttrium oxide, 3% wgt europium oxide and 3% wgt phosphorus pentoxide.
  • Impurities in the admixture mainly consisted of ⁇ 1% wgt aluminium oxide, ⁇ 1% wgt strongium carbonate, ⁇ 1% wgt calcium carbonate, ⁇ 1% wgt magnesium oxide, ⁇ 1% manganese oxide, ⁇ 1% wgt lead oxide,
  • the Spectral Energy data of this material as found is shown in Figure 2.
  • the correlated colour temperature is 2800°K.

Abstract

A luminescent composition including the reaction product of an yttrium-silicon-phosphorus phosphor; and an activating agent selected from the group consisting of lanthanum, cerium, terbium and europium oxide and mixtures thereof. A process for the preparation of a luminescent composition which includes providing a source of yttrium, silicon and phosphorus; and an activating agent selected from the group consisting of lanthanum, cerium, terbium and europium oxide and mixtures thereof; mixing the yttrium, silicon and phosphorus sources together with the activating agent; and firing the mixture at elevated temperature. The luminescent composition can be used for screens or discharge lamps.

Description

LUMINESCENT MATERIAL The present invention relates to luminescent materials and to articles coated with such materials.
Discharge lamps, such as mercury vapour discharge lamps are widely used for general illumination purposes because of their efficient conversion of electrical energy to radiant energy as compared with the standard incandescent lamp.
Research and development has been undertaken in the prior art to produce even more efficient discharge lamps with improved radiation and luminosity capabilities. Numerous patents have been granted relating to improvements in tube design and, in particular, to improvements in the materials used to coat the tube and convert the shorter wavelength ultra-violet radiation given off by the mercury, to radiation having a longer wavelength and a greater spectral distribution.
However there remains a need for discharge lamps exhibiting an increased life span and increased luminosity. Accordingly, it is an object of the present invention to overcome, or at least alleviate, one or more of the difficulties related to the prior art.
Accordingly, in a first aspect of the present invention, there is provided a luminescent composition including the reaction product of an yttrium-silicon-phosphorus phosphor; and an activating agent selected from the group consisting of lanthanum, cerium, terbium and europium oxide and mixtures thereof. Preferably the phosphor is activated by a mixture of three or more of said oxides, for example a mixture of lanthanum, cerium, terbium and europium oxides.
More preferably the activating agent further includes strontium oxide. The luminescent composition according to the present invention may be distinguished from prior art luminescent materials in the use of yttrium-silicon- phosphorus activated phosphors in place of the conventional aluminate or gallate phosphors. For example, conventional aluminate phosphors known in the prior art form an aluminium oxide lattice with various elements positioned within this structure.
However the luminescent material of the present invention forms a silicone oxide lattice with various elements, preferably including europium, which act as activating agents positioned within the structure - these combinations of activating agents form tri-colour mixes with specific spectral emmissions. The use of a yttrium-silicon-phosphorus phosphor may reduce the cost of the luminescent material and may provide increased useful life span and luminosity. The luminescent material may exhibit substantially no reductions in luminosity over time. Luminosity may in fact increase over time.
The silicon source used may be selected from silicic acid, a silicon oxide such as silicon dioxide (e.g. silica), or silicon oxalate. Silicon oxalate is preferred. The quantity of silicon preferred in the final material, expressed in the form of its oxide, is preferably within the range of approximately 10 to 50% by weight, more preferably 10 to 35% by weight, of the total weight of the material.
A range of phosphorus compounds may be utilised in the preparation of the luminescent composition, extending from oxides such as phosphorus pentoxide, through the acids such as orthophosphorous acid, halides such as phosphorus trichloride, oxyhalides such as phosphorus oxychloride, and the like. A preferred phosphorus compound is phosphorus pentoxide. Preferably, the phosphorus will be present, in the form of its oxide, in an amount of from approximately 1 to 20% by weight, more preferably 1 to 10% by weight, based on the total weight of the material. The yttrium source used may be yttrium oxide, preferably in an amount of from approximately 20 to 60% by weight of the total weight of the material.
The lanthanides may generally be provided in the hydride, oxide, hydroxide or halide form. The mixture may be a complex of two or more of such lanthanides, a mixture of individual lanthanides, or a mixture of one or more complexes with one or more individual compounds of such lanthanides. Suitably, the lanthanides will be present in the form of their trivalent oxides, viz M-,0- where M is a lanthanide ion, and will comprise a mixture of the abovementioned individual lanthanides.
The lanthanides may be present in the luminescent composition, in amounts of approximately 1 to 36% by weight, more preferably 9 to 36% by weight. In the preferred mixture of lanthanide oxides, the individual lanthanides are preferably present in the following amounts:
Oxide Weight Basis lanthanum 5-20% cerium 2-8% terbium 1-4% europium 1-4%
In addition to the above constituents, other elements in their appropriate form may be included to modify the spectral qualities of the luminescence. A preferred additive is strontium. Strontium may be provided in the form of its oxide, halide, nitrate, acid, oxyhalide, or the like. Strontium may be present in amounts of approximately 5 to 15% by weight of the total weight of the luminescent material in its oxide form. It has been found that the inclusion of strontium may increase the correlated colour temperature (CCT) of the material. Minor additives can be included to give special effects, or may be naturally present as impurities. The most notable of these include compounds, ions, radicals and other chemical entities of the following elements: aluminium, calcium, manganese, lead, barium, bismuth, boron and chlorine.
The luminescent material may be prepared by known methods such as by solid-state reaction at elevated temperature.
Accordingly in a further aspect of the present - A - invention there is provided a process for the preparation of a luminscent composition which includes providing a source of yttrium, silicon and phosphorus; and an activating agent selected from the group consisting of lanthanum, cerium, terbium and europium oxide and mixtures thereof; mixing the yttrium, silicon, phosphorus and activating agent; and firing the mixture at elevated temperature. The product so formed may have a glaceous structure. The activating agent is preferably a mixture of lanthanum, cerium, terbium and europium oxides. A mixture of the components in the required stoichiometric amounts may be heated to approximately 1200°C to 1750°C, preferably 1458°C to 1700°C, until a glaceous substance is formed.
The product may be subjected to a size reduction step. The substance may be cooled, ground and sieved. The particulate material so formed may for example have a particle size within the range of approximately 1-30 microns. The particulate material may be mixed with a bonding agent such as butyl acetate, xylene, hydroxy ethyl cellulose or water, to form a slurry for coating the inner surface of a low pressure discharge lamp.
Other aspects of the present invention relate to screens coated with the luminescent composition as described above and discharge lamps, particularly mercury vapour discharge lamps containing the material as an internal coating.
Coating of the discharge lamp may also be carried out by known methods. For example, the lamp is initially, internally washed, dried and cooled prior to coating, for example, by an "up flush" method. The "up flush" method comprises pressurising a slurry of the coating material with an inert gas such as argon to force the coating material to rise up the inside of the lamp. A coating at least 60 microns is thus formed on the inner surface of the lamp, and the lamp is drained, cooled and then dried with hot air. A gas braking lehr may then be used for sintering the coating material and removing the coating from the ends of the lamp. The luminescent material according to the invention may be used advantageously in discharge lamps, for example low pressure mercury vapour discharge lamps for general illumination purposes and exhibit wide spectral distribution as illustrated in the accompanying examples. The present invention will now be more fully described with reference to the accompanying examples and to the accompanying drawings which are graphs of the spectral energy distribution of emitted radiation. It should be understood, however, that the description following is illustrative only and should not be taken in any way as a restriction on the generality of the invention described above.
EXAMPLE 1 Material Parts by Weight Parts % Silicone dioxide (SiO-) 60.25 37.80
Yttrium oxide 68.29 42.85
Phosphorous Pentoxide 25.3 15.87
Europium Oxide 5.52 3.48
TOTAL 159.36 TOTAL % 100.00
This mix imparts a colour correlated temperature which has more of the red spectrum.
EXAMPLE 2
Material Parts by Weight Parts %
Silicon dioxide 64.0 40.13
Yttrium oxide 58.3 36.55
Phosphorous pentoxide 7.6 4.77
Cerium oxide 6.0 3.76
Terbium oxide 3.2 2.00
Lanthanum oxide 20.4 12.79
TOTAL 159.5 TOTAL % 100.00 This mix imparts a colour correlated temperature which has more of the green spectrum. EXAMPLE 3
A mixture was made of the following ingredients which were admixed in the stated amounts: 16% wgt silicon oxalate, 15% wgt lanthanum oxide, 6% wgt cerium oxalate, 3% wgt terbium oxide, 27% wgt yttrium oxide, 2% wgt europium oxide, 9% wgt strontium carbonate and 7% wgt phosphorus pentoxide. Impurities in the admixture mainly consisted of <1% wgt aluminium oxide, <1% wgt calcium carbonate, <1% wgt magnesium oxide, <1% manganese oxide, <1% wgt barium chloride, <1% wgt bismuth carbonate and <1% wgt boron oxide.
The mixture was heated in a furnace at 1500°C until a glacious mass formed. The product was then cooled and ground, and a particulate sieved to approximately 2-30 microns.
The mixture was coated on a conventional compact low pressure mercury discharge lamp by a conventional coating technique, and a Spectral Energy Test conducted.
The correlated colour temperature was 5,500°K as depicted in Figure 1.
EXAMPLE 4
A mixture was made of the following ingredients where were admixed and heated in the stated amounts in the same manner as in Example 1: 29% wgt silicon oxalate, 9% wgt lanthanum oxide, 4% wgt cerium oxide, 2% wgt terbium oxide, 49% wgt yttrium oxide, 3% wgt europium oxide and 3% wgt phosphorus pentoxide. Impurities in the admixture mainly consisted of <1% wgt aluminium oxide, <1% wgt strongium carbonate, <1% wgt calcium carbonate, <1% wgt magnesium oxide, <1% manganese oxide, <1% wgt lead oxide,
<1% wgt barium chloride, <1% wgt bismuth carbonate and <1% wgt boron oxide.
The Spectral Energy data of this material as found is shown in Figure 2. The correlated colour temperature is 2800°K.
These results and those of the previous Example indicate excellent spectral properties for the luminescent materials.
Finally, it is to be understood that various other modifications and/or alterations may be made without departing from the spirit of the present invention as outlined herein.

Claims

Claims
1. A luminescent composition including the reaction product of an yttrium-silicon-phosphorus phosphor; and an activating agent selected from the group consisting of lanthanum, cerium, terbium and europium oxide and mixtures thereof.
2. A luminescent composition according to claim 1, wherein the activating agent includes three or more of said oxides.
3. A luminescent composition according to claim 1, wherein the activating agent is a mixture of lanthanum, cerium, terbium and europium oxides.
4. A luminescent composition according to claim 1, wherein the activating agent further includes strontium oxide.
5. A luminescent composition according to claim 4, wherein the strontium oxide comprises 5 to 15% by weight of the total weight of the composition.
6. A luminescent composition according to claim 1, wherein the yttrium constitutes, in its oxide form, approximately 20 to 60% by weight based on the total weight of the composition; the silicon constitutes, in its oxide form, approximately 10 to 50% by weight based on the total weight of the composition; and the phosphorus constitutes, in its oxide form, approximately 1 to 20% by weight based on the total weight of the composition.
7. A luminescent composition according to claim 6 , wherein the lanthanide(s) is present in an amount of approximately 1 to 36% by weight based on the total weight of the composition.
8. A luminescent composition according to claim 6, wherein additives/impurities are present in an amount of less than approximately 1% by weight of the total weight of the composition.
9. A luminescent composition according to claim 8, wherein the impurities are selected from the group consisting of aluminium, calcium, magnesium, manganese, lead, barium and boron.
10. A process for the preparation of a luminscent composition which includes providing a source of yttrium, silicon and phosphorus; and an activating agent selected from the group consisting of lanthanum, cerium, terbium and europium oxide and mixtures thereof; mixing the yttrium, silicon and phosphorus sources together with the activating agent; and firing the mixture at elevated temperature.
11. A process according to claim 10, wherein the product so formed has a glaceous structure and is subjected to a size reduction step.
12. A screen coated with a luminescent composition according to claim 1.
13. A discharge lamp internally coated with a luminescent composition according to claim 1.
14. A luminescent composition substantially as herein described with reference to any one of Examples 1 to 4.
PCT/AU1993/000276 1992-01-13 1993-06-11 Luminescent material WO1994029403A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
AU31166/93A AU3116693A (en) 1992-01-13 1993-01-13 Luminescent material
PCT/AU1993/000276 WO1994029403A1 (en) 1993-01-13 1993-06-11 Luminescent material
CN93108022.3A CN1097454A (en) 1992-01-13 1993-07-12 Luminescent material

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Application Number Priority Date Filing Date Title
AU31166/93A AU3116693A (en) 1992-01-13 1993-01-13 Luminescent material
PCT/AU1993/000276 WO1994029403A1 (en) 1993-01-13 1993-06-11 Luminescent material

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WO1994029403A1 true WO1994029403A1 (en) 1994-12-22

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Citations (11)

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JPS5692984A (en) * 1979-12-26 1981-07-28 Hitachi Ltd Fluorescent material and its preparation
JPS5790086A (en) * 1980-11-27 1982-06-04 Toshiba Corp Phosphor
JPS59113084A (en) * 1982-12-21 1984-06-29 Toshiba Corp Fluorescent material
JPS59226088A (en) * 1983-06-07 1984-12-19 Toshiba Corp Green light-emitting fluorescent material
GB2142775A (en) * 1983-06-07 1985-01-23 Toshiba Kk Fluorescent lamp
JPS62579A (en) * 1985-06-26 1987-01-06 Toshiba Corp Production of rare earth green phosphor
JPS63154787A (en) * 1986-12-19 1988-06-28 Toshiba Corp Phosphor
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DE2841545A1 (en) * 1977-10-03 1979-04-12 Philips Nv LUMINOUS EARTH ALPHOSPHATE
US4810416A (en) * 1979-08-03 1989-03-07 Kasei Optonix, Ltd. Borate phosphor
JPS5692984A (en) * 1979-12-26 1981-07-28 Hitachi Ltd Fluorescent material and its preparation
JPS5790086A (en) * 1980-11-27 1982-06-04 Toshiba Corp Phosphor
JPS59113084A (en) * 1982-12-21 1984-06-29 Toshiba Corp Fluorescent material
JPS59226088A (en) * 1983-06-07 1984-12-19 Toshiba Corp Green light-emitting fluorescent material
GB2142775A (en) * 1983-06-07 1985-01-23 Toshiba Kk Fluorescent lamp
JPS62579A (en) * 1985-06-26 1987-01-06 Toshiba Corp Production of rare earth green phosphor
JPS63154785A (en) * 1986-12-18 1988-06-28 Toshiba Corp Phosphor
JPS63154787A (en) * 1986-12-19 1988-06-28 Toshiba Corp Phosphor
JPH01234490A (en) * 1988-03-16 1989-09-19 Toshiba Corp Fluorescent substance and fluorescent lamp

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