FI92443C - A method for improving the durability of a fluorescent lamp's light output and fluorescent lamp - Google Patents

Description

92443

A method for improving the light output stability of a fluorescent lamp and a fluorescent lamp

Divided by application 851 785 5

This invention relates to phosphor. More specifically, the present invention relates to a method for improving the light output stability of a fluorescent lamp and a fluorescent lamp. The fluorescents are used in mercury-discharge lamp-10 lamps and erl electronic lalttelden display surfaces. It has been found that various improvements in the performance of the phosphor can be obtained if the phosphor is coated with a protective film containing pigment. Numerous attempts have been made to patch the outer surface 15 of individual phosphor components with a protective bale stellar. However, in previous baling methods in the art, it has not been possible to make a part with a continuous protective baling, the thickness of which is preferably substantially uniform on the outer surface of the part.

Improving the performance of fluorescent components with a continuous protective coating can be particularly useful in improving the performance of fluorescent lamps.

The present invention relates to a method for improving the light output stability of a parasitic fluorescent lamp, which method comprises the steps of depositing a continuous alumina coating on individual portions of a fluorescent lamp finely divided fluorescent powder to form a corrugated dome, wherein at least one of the phosphor layers has a phosphor component consisting of individually and continuously corrugated phosphor components; and a parasitic-35 agent-treated dome for processing into a finished fluorescent lamp.

92443 2

According to another aspect of the present invention, there is provided a fluorescent lamp comprising a glass dome, the inner surface of the glass dome being coated with one or more phosphor layers, wherein at least one fluorescent layer has a phosphor component comprising miinioksidipaållysteella.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic representation of a device suitable for use in the method of the present invention, and Fig. 2 is a schematic side view of a lamp.

For a better understanding of the present invention, in conjunction with its other objects, advantages, and uses, reference is made to the following description and appended claims in reference to the foregoing drawings.

The method of the present invention involves the formation of a continuous protective coating on the phosphor components 20 by chemical gas phase vapor deposition, wherein the phosphor components are suspended in a fluidized bed. The suspended particles are exposed to the vaporized precursor material in the first temperature state, wherein the first temperature state is lower than the temperature state in which the precursor material is distributed. When the precursor material envelops the particles, the precursor material is reacted to form a continuous protective bale for the individual particles in a second temperature state that is higher or equal to the temperature in which the precursor material reacts to form a protective coating material.

The fluidized bed is formed by passing an inert gas through a series of phosphor particles to suspend the particles in an inert gas stream. Inert gases suitable for use in this process include nitrogen, argon, helium, neon, or mixtures thereof. In addition to storing the phosphor particles in the fluidized bed, an inert gas acts as a carrier gas. The volatile bale precursor material is vaporized in an inert gas before it enters the reaction chamber in which the phosphor components are suspended. Preferably, the vapor from the bale precursor material saturates the carrier gas. As the carrier gas containing the vaporized batch precursor material passes upwardly through the composite particles to suspend the particles into a fluidized bed, the particles are enveloped in the hcSyryllM of the bale precursor material.

In the present method, the suspended particles are exposed to the vaporized bale precursor material in the first temperature state to surround the particles with the bale precursor material, the first 1 m , to form a protective coating having a defined thickness of the front cover for individual phosphor components 20, which second lamp state is higher than or equal to the temperature in which the bale precursor material reacts to form a protective bale.

The fluidized bed preferably maintains a temperature gradient ranging from the lowest temperature> ·, / 25 to the highest temperature. The lowest ISmpS state must be lower than the IMmp state in which the bale precursor material disperses, and the highest temperature state must be equal to or higher than the IMmp state in which the bale precursor material reacts to form the desired coating material.

l · If necessary, an oxidizing gas is introduced into the fluidized bed from a separate M carrier gas containing a vaporized bale precursor material. Examples of suitable oxidizing gases are air and oxygen. The oxidizing gas can be mixed with an inert diluent gas.

4,92443 The thickness of the coating depends on the time used to carry out the method, the temperature of the evaporation source, the flow rate across the evaporation source and the surface area of the phosphor.

Examples of phosphor coating materials that can be applied by the method of the present invention include metal or non-metal oxides. Preferred coating materials are refractory oxides such as alumina or yttriuroxide.

A chemical compound or chemical composition suitable for use as a precursor material for a coating in the process of the present invention must be vaporizable. Organic or non-metallic organic or alkoxy compounds of the desired oxide coating material which vaporize under the conditions used in the process can be used as precursor materials for the coating in the present invention. The metal acetyl acetonates of the oxide coating material can also be used as precursor materials in the present process.

For example, some suitable alumina precursor hematerials are represented by the general formula

Rx (OR ') 3.xA1 <d · 25 where 0 ^ x <3 and x are an integer and R and R' are lower alkyl groups such as: -CH3; -C2H5; C3H7; or -C4H9. Examples of suitable yttrium oxide precursor materials show the general formula

30 Rx (OR ') 3.xY

• · wherein 0 <x <3 and x is an integer and R and R 'are lower alkyl groups such as -CH3; -C2H5; C3H7; -C4H9; or -C5HU.

This list of examples of suitable precursor materials for the coating 35 in the form of alumina or yttrium oxide is not necessarily to be construed as limiting. Any alkyl, alkoxy or acetyl acetonate compound of aluminum or yttrium which can be vaporized on an inert gaseous support under the conditions used in the process can be used as a precursor material for the coating with counter-alumina coatings or coatings.

If an oxygen-containing bulk precursor material, such as an alkoxide or acetylacetonate, is used in the process of the present invention, the use of an oxidizing gas is optional.

In order to implement the fluidized bed and chemical vapor deposition method of the present invention, the phosphor powder particles 15 must be fluidizable. Fluorescent powders having an average particle size in the range of about 20 to 80 micrometers or greater can be fluidized without difficulty or only with minimal difficulty. However, there are difficulties in trying to fluidize fine phosphor powders, for example phosphor powders with an average particle size of less than about 20 micrometers. The difficulty in fluidizing the particles of the finely divided phosphor is due to the inter-particle holding forces which cause agglomeration and crosslinking between the agglomerates. Tåma ka-. . The crosslinking and crosslinking of the agglomerates usually causes the formation of channels through the bed, whereby the gas passes through the channels without fluidizing the particles. Under these conditions, the powder layer expands only slightly or not at all.

Particles of finely divided phosphor powders such as cold white halophosphate fluorescent substances belonging to the "C" class of the Gel-dart classification scale can be fluidized and coated by the method of the present invention. In order to fluidize the particles 35 of the finely divided phosphor powder according to the present invention. In a small amount, about 1% by weight of the phosphor, the fluidizing aid should be mixed with the phosphor powder to form a uniform mixture. Preferably, a fluidizing aid is used in an amount less than or equal to 5 to about 0.05% by weight based on the phosphor used. Suitable fluidizing aids include low particle size alumina, for example Aluminum Oxide C, or low particle size silica. Alternatively, the fluidization of the finely divided phosphor powders can be performed using an additional mixture of phosphor powder particles suspended in the carrier gas stream. This additional mixing can be performed by various mixing means, such as a mechanical stirrer and preferably by means of a high speed paddle stirrer. In a preferred embodiment of the present invention, both the fluidizing aid and the additional mixture are used together to fluidize the phosphor powder and expand the fluidized bed. A schematic representation of a fluidized bed reactor that can be used in the process of the present invention is shown in Figure 1.

In Figure 1, the inlet pipe 11 transfers an inert carrier gas to a stainless steel bubbler 12, which contains the bale precursor material to be vaporized, usually in liquid form. In the bubbling device, 12 * 25 bale pre-material is vaporized into the carrier gas. The carrier gas containing the precursor can be diluted to form suitable concentrations of reactants. A carrier gas containing vaporized bale precursor material is transferred through a tube 13 to a quartz-30 glass reaction tube 15. A carrier gas containing. The preform material of the baler passes through a porous quartz melt 14 in the tube 15, which is used to support the phosphor powder layer 16. The tube 15 also has a variable mixer 17. A group of openings 18 are arranged around the axis of the annular variable mixer 17. · ·

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92443 7 an oscillating plate 19, through the openings of which an oxidizing gas with or without an inert diluting gas enters the outlet 15. A quartz glass reaction tube 15 surrounds the furnace 20.

The inlet pipe 11 which transfers the inert gas to the bubbling device 12 and the bubbling device 12 containing the vaporizable coating precursor material in liquid form are both heated to a temperature which causes the precursor material to evaporate into the inert carrier. The Syot-10 tube 13, which feeds a gas stream containing hydration to the quartz glass reaction tube 15, is heated to a higher temperature than the tube 11 and the bubbling device 12 to keep the precursor material hydrated as it passes into the reaction tube 15.

An important feature of the preferred embodiment of the present invention is the maintenance of a temperature gradient in a fluidized bed. The porous sintered section of the reaction tube is heated to a temperature and maintained there at a temperature lower than the temperature at which the precursor material of the coating 20 decomposes. This region of the reaction tube located at the bottom of the fluidized bed has the lowest temperature of the temperature gradient in which the fluidized bed is maintained.

Feeding the precursor material to the fluidized bed by means of a flow of inert carrier gas and maintaining the sintered area at a temperature lower than the decomposition temperature of the precursor material in the outer fluid (which is also lower than the high temperature of the fluidized bed gradient). existing hoyry. The inert carrier of the coating precursor material into the reaction tube by means of a gas removes the inconvenience caused by the premature reaction of the precursor material to the desired coating material or undesirable by-product. The premature reaction 35 causes the actual coating material or 8 92443 by-products to form from the bubbling device 12 in the transfer tube 13 leading to the reaction tube 15, below the sintered portion or in the porous openings of the sintered portion 14 itself. Premature reaction can further cause clogging of the sintered part 5 and interruption of the baling process. In addition, the difficulty caused by the decomposition of the precursor material in the sintered region can be avoided by maintaining in the sintered region a temperature below the temperature at which the precursor material decomposes thermally. Dispersion of the precursor material, which does not contain oxygen, for example alkyl compounds, causes the transfer of the color of the base mass to the coated phosphor and / or the transfer of carbonaceous impurities to the fluorescent coating, which impurities absorb the fluorescent light emitted and / or emitted.

In the process of this invention, the oxidizing gas, if required, is fed to the fluidized bed separately from the carrier gas. The oxidizing gas may be undiluted or may be diluted with inert gas. The oxidizing gas is preferably added to the fluidized bed at a temperature lower than the highest temperature but higher than the lowest temperature. Most preferably, the oxidizing gas is added to the fluidized bed at a temperature gradient where the temperature is lower than the temperature at which a chemical change occurs in the precursor material of the coating in the presence of the oxidizing gas. This minimizes fouling of the coating material by carbon and other carbonaceous compounds.

The highest temperature of the temperature gradient must be sufficiently high that the precursor material of the coating surrounding the outer surfaces of the phosphor components reacts to form the desired coating material. As the precursor material reacts after the vapor of the precursor material coats the surfaces of the phosphor components, the coating 35 is continuous, i. the coating does not form very finely divided

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92443 9 individual particles of powder, but is, in contrast, a very uniform coating which mimics the microscopic features naturally present in the granular substrate of the phosphor. Påallyste is not crystalline.

The following is an example of the preparation of rolled phosphor powder particles by methods according to preferred embodiments of the present invention, which is not to be construed as limiting the invention.

Example 1 In this example, a cold white alkaline earth halide phosphate fluorescent powder was baled with alumina in accordance with the present invention using the apparatus shown in Figure 1. A fluidized bed with an inner diameter of 4.0 cm was used in the method. 15,200 g of calcium halophosphate phosphor powder (Cool White No. 4459, sold by the Chemical and Metallurgical Division of GTE Products Corporation, Towanda, Pennsylvania) and 0.1 g (0.05% by weight) of Aluminum Oxide C, sold by Degussa Inc., a fluidizing aid, was mixed together in a polyethylene container to obtain a uniform dispersion containing the fluidizing aid of Aluminum Oxide C evenly distributed in the alkaline earth metal halophosphate powder. A mixture of halophosphate fluorescent powder and fluidizing aid was added to a quartz glass reaction tube 15 to form a phosphor layer. Liquid trimethylaluminum was used in a stainless steel bubbler 12 as a precursor material for the coating. The carrier gas was bubbled into trimethylaluminum liquid to form a carrier gas containing vaporized trimethylaluminum. The carrier gas containing vaporized trimethylaluminum was diluted with an inert gas and then transferred through a transfer tube 13 to a quartz glass reaction tube 15. Nitrogen-diluted oxygen gas was introduced into the fluidized bed through openings 18 located in a circumferentially variable oscillator. 19. The oscillating agitator was operated at a rate of 60 cycles per minute. openings and prevent clogging of these openings.

The nitrogen gas pipe 11 leading to the bubbling device 10 12 and the bubbling device 12 were both heated to a temperature of 30 ° C and kept at this temperature. The tube 13 leading from the bubbler 12 to the bottom of the quartz glass reaction tube 15 was heated to a lamp space of about 45 ° C and kept at this temperature.

15 Oven 20 was a three-zone oven heated by electric heaters. the sintered part was kept at a temperature of about 60-150 ° C; the oxidizing gas intake area located above the alternating plate was heated to a temperature of about 400 ° C and maintained at that temperature; and the area above the ha-20 decomposing gas input range was heated to and maintained at a temperature of about 650 ° C, although 450 ° C and above may be used.

A stream of nitrogen of about 100 cc / min was passed through the bubbler 25 and nitrogen gas containing vaporized trimethylaluminum (transfer about 700 mg / h) was passed through line 13 to the reaction tube 15 at a flow rate of about 450 cc / min. A stream of oxygen gas diluted with nitrogen was introduced into the reaction tube through a second inlet-3 0 tube 21 at a flow rate of about 450 cm 3 / min. The concentration ratio between oxygen and alkyl was found to affect the basic color of the coated particles prepared according to the present method. An oxygen to ratio ratio of about 200: 1 to trimethylaluminum was maintained in this reaction to give a white base color (a ratio of less than li 92443 11 of about 200: 1 may cause poor or non-white base color variation).

The procedure was continued for 6 hours and a alumina bale layer having a thickness of about 150 x 10 x 10 in was formed on the phosphor particles.

Alkaline alkaline earth halophosphate particles were removed from the reaction tube.

Electron microscopic examination of the coated phosphor components of the example of Taina showed a uniform angle-10 accurate alumina coating on the cold white alkaline earth metal halophosphate phosphor components. In this example, the continuity and angular nature of the bale applied to the phosphor components was determined by repeating the microscopic features of the phosphor substrate. However, the microscopic features of the coated particles are visibly less pronounced when compared to the microscopic features of the uncoated particle. In addition, it was found that the bale was not crystalline according to the reflection electron diffraction study.

Auger analysis of the surface of the palletized particle showed that complete surface coverage with alumina had been achieved within the limits of the analysis (99.8%), which analysis was based on a peak-to-peak decrease in the alkali metal halophosphate phosphor of the alkali metal. : / Ic, paallystated λ% coverage = (1--1 x V Ic, paallystamatory

30 L J

Example 2

In the TassS example, particles of the cold white alkaline earth metal phosphate powder were pSally coated with alumina by the method of the present invention using the apparatus shown in Example 1. 300 grams of calcium halophosphate phosphor powder (Cool White No. 4459, supplied by the Chemical and Metallurgical Division of GTE Products Corporation, Towan, Pennsylvania) and 0.15 grams (0.05% by weight) of Aluminum 5 Oxide C, sold Degussa Inc., a fluidizing aid, was mixed together dry in a polyethylene vessel to obtain a uniform dispersion containing Aluminum Oxide C fluidizing aid thoroughly mixed with an alkaline earth metal halophosphate supernatant. Liquid trimethylaluminum was used in a stainless steel bubbler as a precursor material for the coating. The carrier gas was bubbled into the trime-15 aluminum aluminum liquid to form a carrier gas containing trimethylaluminum vaporized. The carrier gas containing vaporized trimethylaluminum was transferred through a feed tube to a quartz glass reaction tube. Oxygen diluted in nitrogen was introduced into the fluidized bed through holes in the shaft of the algae-20 algae agitator. The oscillating mixer was operated at 60 cycles per minute.

The bubbler and the nitrogen gas inlet tube were both heated to 30 ° C and maintained at this temperature. The tubes leading from the bubbler to the bottom of the quartz glass reaction tube were heated to a temperature of about 45 ° C and maintained at that temperature.

The sintered section of the reaction tube was maintained at a temperature of about 60-150 ° C; the oxidizing gas inlet located above the oscillating plate was heated to> 400 ° C and maintained at this temperature, and the area above the oxidizing gas core was heated to about 550 ° C and maintained at that temperature.

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92443 13

A stream of nitrogen at a rate of about 100 cm 3 / min was introduced into the bubbler and nitrogen gas containing vaporized trimethylaluminum was introduced into the reaction tube by means of a nitrogen carrier gas at a rate of about 550 cm 3 / min.

5 Oxygen gas diluted with nitrogen gas was introduced into the reaction tube through another core tube. The oxygen gas flow rate was 495 cm 3 / min and the nitrogen diluent was about 50 cm 3 / min. An oxygen to trimethylaluminum ratio of about 200: 1 was maintained during this reaction to give a white color 10.

The procedure was continued for 6 hours and an alumina coating with a thickness of about 100 x 10'10 m was formed on the phosphor component.

In this example, electron microscopic examination of the coated phosphor components 15 showed a uniform, angular coating of alumina with cold white alkaline earth metal halophosphate phosphor components. In this example, the continuous and angular nature of the coating applied to the phosphor components became apparent from the repetition of the microscopic features of the phosphor components. However, the microscopic features of the coated particles are clearly less pronounced than the microscopic features of the uncoated particle.

Example 3 In this example, a cold white alkaline earth metal halophosphate phosphor powder was coated with alumina by the method of the present invention using the apparatus shown in Example 1. 300 grams of calcium halophosphate phosphor powder (Cool White No. 4459, sold by the Chemical and Metallurgical Division of GTE Products Corporation, Towanda, Pennsylvania) and 0.15 grams (0.05% by weight) of Aluminum Oxide C lubricant excipient, sold by Degussa Inc., were mixed together in a dry polyethylene vessel to obtain a uniform dispersion containing Aluminum Oxide C fluidizing aid evenly distributed in the alkaline earth metal halophosphate phosphor. A mixture of halophosphate fluorescent powder and fluidizing aid was added to a quartz glass reaction tube to form a phosphor layer. Liquid-5 trimethylaluminum was used in a stainless steel bubbler as a precursor material for the coating. The carrier gas was bubbled through a trimethylaluminum liquid to form a stock containing trimethylaluminum vaporized. The carrier gas containing vaporized trimethyl-10 aluminum was fed via a feed tube to a quartz glass reaction tube. Oxygen-diluted oxygen gas was introduced into the fluidized bed through the openings in the shaft of the agitator. The oscillating mixer was operated at a rate of 60 and 15 soos per minute.

The bubbling device and the nitrogen gas supply pipe to the bubbling device were both heated to a temperature of 30 ° C and maintained at this temperature. The tube leading from the bubbler to the bottom of the quartz glass reaction tube was brought to a temperature of about 45 ° C and maintained at that temperature.

The sintered section of the reaction tube was maintained at a temperature of about 60-150 ° C; the oxidizing gas inlet located above the oscillating plate was heated to a temperature of about 400 ° C and maintained at this temperature, and the area above the oxidizing gas inlet was maintained at about 550 ° C.

A stream of nitrogen at a rate of about 150 cm 3 / min was introduced into the bubbler and nitrogen gas containing vaporized trimethyl-30 aluminum was introduced into the reaction tube by means of nitrogen gas at a flow rate of about 500 cm 3 / min. A stream of oxygen gas diluted with nitrogen gas was introduced into the reaction tube through a second inlet tube. The oxygen flow rate was about 495 cm 3 / min and the nitrogen diluent about 50 cm 3 / min. An oxygen content ratio of about 200: 1 to trimethyl-92443 aluminum was maintained during this reaction to obtain a colorless white mass.

The procedure was continued for 4 hours and an alumina coating with a thickness of about 100 x 10 10 m was formed on the phosphor component.

Electron microscopic examination of the coated phosphor particles of this example showed a uniform and angular alumina dipstick on the cold white alkaline earth metal phosphate phosphor particles. According to the example of Ta-10, the continuous and angular nature of the baling applied to the phosphor components was demonstrated by the repetition of the microscopic features of the phosphor substrate. However, the microscopic features of the coated particles are clearly less pronounced than the microscopic features of the uncoated particles.

Example 4

In this example, a powder of a cold white alkaline earth metal phosphate phosphate was coated with alumina by the method of the present invention using the apparatus shown in Example 1. 300 grams of calcium halophosphate phosphor powder (Cool White No. 4459, sold by the Chemical and Metallurgical Division of GTE Products Corporation, Towanda, Pennsylvania) and 0.15 grams (0.05% by weight) of Aluminum Oxide C 25 fluidizing aid, sold by Degussa Inc. ., were mixed dry together in a polyethylene vessel to obtain a uniform dispersion containing Aluminum Oxide C fluidizing aid thoroughly distributed in alkaline earth metal halophosphate powder. A mixture of halophosphate fluorescent powder and fluidizing aid was added to a quartz glass reaction tube to form a phosphor layer. Liquid trimethylaluminum was used in a stainless steel bubbler as a precursor material for the coating. The carrier gas was bubbled into the trimethylaluminum liquid to form a carrier gas containing trimethylaluminum vaporized. The carrier gas containing vaporized trimethylaluminum was fed through a feed tube into a quartz glass reaction tube. Oxygen-diluted oxygen gas was fed to the fluidized bed through holes in the shaft of the variable mixer. The variable agitator was operated at 60 cycles per minute.

The bubbler and the nitrogen gas tube to the bubbler were both heated to a temperature of 30 ° C and maintained at this temperature. The tube leading from the bubbler to the bottom of the quartz-10 glass reaction tube was heated to a temperature of about 45 ° C and kept at this temperature.

The sintered section of the reaction tube was maintained at a temperature of about 60-150 ° C; the oxidizing gas inlet located above the vMrMellating plate was heated to a temperature of about 400 ° C and maintained at that temperature; and the area above the oxidizing gas intake was heated to a lamp space of about 550 ° C and maintained at that temperature.

A nitrogen flow of about 100 cm 3 / min was introduced into the bubbler and nitrogen gas containing vaporized trimethylaluminum was fed to the reaction tube at a flow rate of about 550 cm 3 / min by means of a nitrogen stock. A stream of oxygen gas diluted with nitrogen gas was • introduced into the reaction tube through a second inlet line. The oxygen flow rate was about 495 cm 3 / min. and a nitrogen diluent of about 50 cm 3 / min. An oxygen content ratio of about 200: 1 to trimethylaluminum was maintained during this reaction to give a white color to the pulp.

The procedure was continued for 9 hours and an alumina coating with a thickness of about 150 x 10-10 m was formed on the phosphor components.

In this example, electron microscopic examination of the coated phosphor components showed a cold-white earthyness of a smooth and high-precision alumina coating.

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92443 with 17 meat phosphate phosphor components. In this example, the continuous and angular nature of the bale applied to the phosphor component was demonstrated by the repetition of the microscopic features of the phosphor substrate. However, the microscopic features of the coated 5 particles were clearly less pronounced than the microscopic features of the uncoated particle.

Example 5 In this example, powder particles of an off-white alkaline earth metal-10 phosphate phosphate powder were coated with alumina by the method of the present invention using the apparatus shown in Example 1. 300 grams of calcium halophosphate parasitic powder (Cool White No. 4459, sold by the Chemical and Me-15 Tallurgical Division of GTE Products Corporation, Towanda, Pennsylvania) and 0.15 grams (0.05% by weight) of Aluminum Oxide C fluidizing aid, sold by Degussa Inc., were mixed together dry in a polyethylene vessel to obtain a uniform dispersion containing Aluminum Oxide C fluidizing aid evenly distributed in the alkaline earth metal halophosphate phosphor powder. A mixture of halophosphate phosphor powder and fluidizing aid was added to a quartz glass reaction tube to form a phosphor layer. Liquid trimethylaluminum was used in: 25 stainless steel bubblers as a precursor material for the coating. The carrier gas was bubbled into the trimethylaluminum liquid to form a base of vaporized trimethylaluminum. The carrier gas containing vaporized trimethylaluminum was passed through 30 feed tubes to a quartz glass reaction tube. Oxygen-diluted oxygen gas was introduced into the fluidized bed through holes located in the shaft of the oscillating stirrer. The oscillating mixer was operated at 60 cycles per minute.

18 92443

The bubbler and the nitrogen gas pipe leading to the bubbler were both heated to a temperature of 30 ° C and maintained at that temperature. The tube leading from the bubbler to the bottom of the quartz glass reaction tube was heated to a temperature of about 45 ° C and maintained at that temperature.

The sintered section of the reaction tube was maintained at a temperature of about 60-150 ° C; the oxidizing gas inlet located above the oscillating plate was heated to a temperature of about 400 ° C and maintained at that temperature, and the area above the oxidizing gas core was heated to about 550 ° C and maintained at that temperature.

A stream of nitrogen at a rate of about 150 cm 3 / min was introduced into the bubbler and nitrogen gas containing vaporized trimethylaluminum was introduced into the reaction tube by means of a nitrogen carrier gas at a flow rate of about 550 cm 3 / min. A stream of oxygen gas diluted with nitrogen was introduced into the reaction tube through a second core tube. The oxygen flow rate was about 495 cc / min and the nitrogen diluent was about 50 cc / min. An oxygen to ratio ratio of about 200: 1 to trimethylaluminum was maintained during this reaction to give a white color to the base mass.

The procedure was continued for 9 hours and an alumina coating with a thickness of about 150 x 10.10 m was formed on the phosphor components.

According to this example, electron microscopic examination of the coated phosphor particles showed a uniform, angularly accurate alumina coating on the cold white ... 30 alkaline earth metal halophosphate phosphor particles. In the example, the continuous and angular nature of the coating applied to the phosphor components was demonstrated by the repetition of the microscopic features of the phosphor substrate. However, the microscopic nature of the coated particle is clearly less pronounced than the microscopic features of the uncoated particle.

* · ·

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92443 19

Example 6 In this example, a powder of a cold white alkaline earth metal halophosphate fluorescent material was coated with alumina by the method of the present invention using the apparatus shown in Example 1. 300 grams of calcium halophosphate phosphor powder (Cool White No. 4459, sold by the Chemical and Metallurgical Division of GTE Products Corporation, Towanda, Pennsylvania) and 0.15 grams (0.05% by weight) of Aluminum Oxide C -le-10 instant excipient, sold Degussa Inc., were mixed together in a dry polyethylene vessel to obtain a uniform dispersion containing Aluminum Oxide C fluidizing aid and distributed throughout the alkaline earth metal halophosphate phosphor powder. A mixture of the halophosphate phosphor and the fluidizing aid was added to a quartz glass reaction tube to form a phosphor layer. Liquid trimethylaluminum was used as a precursor material for the coating in a stainless steel bubbler. The carrier gas was bubbled into the trimethylaluminum-20 liquid to form an evaporated trimethylaluminum-containing carrier gas. The carrier gas containing vaporized trimethylaluminum was fed through a feed tube into a quartz glass reaction tube. Oxygen-diluted oxygen gas was injected into the fluidized bed through openings in the shaft of the variable mixer. The oscillating mixer was operated at 60 cycles per minute.

The bubbler and the nitrogen gas tube leading to the bubbler were both heated to a temperature of 30 ° C and maintained at that temperature. The tube leading from the bubbler to the bottom of the quartz glass reaction tube was heated to a temperature of 45 ° C and maintained at that temperature.

The sintered section of the reaction tube was maintained at a temperature of about 60-150 ° C; the oxidizing gas inlet located 35 above the oscillating plate was heated to a temperature of about 400 ° C and maintained there, and the area above the oxidizing gas inlet was heated to about 550 ° C and maintained at that temperature.

5 A stream of nitrogen gas at a rate of about 150 cm 3 / min was introduced into the bubbler and nitrogen gas containing vaporized trimethylaluminum was introduced into the reaction tube by means of a nitrogen stock at a flow rate of about 500 cm 3 / min. A stream of oxygen gas diluted with nitrogen was fed to the 10 reaction tubes through the second inlet tube. The oxygen flow rate was about 495 cm 3 / min and the nitrogen diluent about 50 cm 3 / min. An oxygen content to trimethylaluminum ratio of about 200: 1 was maintained during this reaction to obtain a white base mass of vM.

The procedure was continued for 8 hours and an alumina bale layer with a thickness of about 200 x 10.10 m was formed on the phosphor components.

In this example, electron microscopic examination of the coated phosphor particles showed a uniform, angular-20 accurate alumina coating formed on the particles of the cold white alkaline earth metal halophosphate phosphor. The continuous and angular nature of the coating applied to the phosphor components was demonstrated by the repetition of the microscopic features of the phosphor substrate. However, the microscopic features of the ‘25 particle of the pallet are clearly less pronounced than the microscopic features of the uncoated particle.

Example 7

In this example, a cold white alkaline earth metal halophosphate phosphor powder was coated with alumina by the method of the present invention using the apparatus of Example 1. 300 grams of calcium halophosphate phosphor powder (Cool White No. 4459, sold by Chemical and Metallurgical 35 Division of GTE Products Corporation, Towanda, Pennsylvania 21 92443) and 0.15 grams (0.05% by weight) of Aluminum Oxide C lubricant excipient , sold by Degussa Inc., was mixed together in a dry polyethylene vessel to obtain a uniform dispersion containing Aluminum Oxide C fluidizing aid evenly distributed in the alkaline earth metal halophosphate powder. The halophosphate phosphor powder and fluidizing aid were added to a quartz glass reaction tube to form a phosphor layer. Liquid trimethylaluminum was used in a stainless steel bubble as a 10-stage precursor material. The carrier gas was bubbled into the trimethylaluminum liquid to form a carrier gas containing trimethylaluminum. The carrier gas containing vaporized trimethylaluminum was fed via a feed tube to a quartz glass reaction tube. Oxygen-diluted oxygen gas was introduced into the fluidized bed through openings in the shaft of the oscillating stirrer. The vibrating mixer was operated at 60 cycles per minute.

The bubbler and the nitrogen-20 gas tube leading to the bubbler were both heated to a temperature of 30 ° C and kept at that temperature. The tube leading from the bubbler to the bottom of the quartz glass reaction tube was heated to a temperature of 45 ° C and kept there.

The sintered section of the reaction tube was maintained at a temperature of about 60-150 ° C; the oxidizing gas inlet above the alternating plate was heated to and maintained at a temperature of about 400 ° C, and the area 30 above the oxidizing gas inlet was heated to about 550 ° C and held at that temperature.

A stream of nitrogen at a rate of about 150 cm 3 / min was introduced into the bubbler and nitrogen gas containing vaporized trimethylaluminum was transferred to the reaction tube at a flow rate of about 500 • · - 22 92443 cm 3 / min by means of a nitrogen gas carrier. A stream of oxygen gas diluted with nitrogen gas was fed to the reaction tube through a second inlet tube. The oxygen flow rate was about 495 cm 3 / min and the nitrogen diluent about 50 cm 3 / min. An oxygen content ratio of about 200: 1 to tri-5 methylaluminum was maintained during this reaction to obtain a colorless white base mass.

The procedure was continued for 12 hours and an alumina coating with a thickness of about 300 x 10.10 m was formed on the phosphor component.

Electron microscopic examination of the coated phosphor components of this example showed a uniform, angular alumina coating formed on the particles of the cold white alkaline earth metal halophosphate phosphor. In the example, the continuous and angular nature of the påå-15 coating applied to the phosphor components was demonstrated by the repetition of the microscopic features of the phosphor substrate. The microscopic features of the coated particle were clearly less pronounced than the microscopic features of the uncoated particle.

Example 8 In this example, particles of a cold white alkaline earth metal halophosphate phosphor powder were coated with alumina by the method of the present invention using the apparatus shown in Example 1; 25 ta. 300 grams of calcium halophosphate phosphor powder (Cool White No. 4459, sold by the Chemical and Metallurgical Division of GTE Products Corporation, Towanda, Pennsylvania) and 0.15 grams (0.05% by weight) of Aluminum Oxide C fluidizing aid, sold by Degussa Inc. , was mixed on a dry basis in a polyethylene dish to obtain a uniform dispersion containing Aluminum Oxide C fluidizing aid evenly distributed in the alkaline earth metal halophosphate phosphor powder. A mixture of the halophosphate fluorescent powder and the fluidizing aid was added to a quartz glass reaction tube to form a phosphor layer.

• · · 23 92443

Liquid trimethylaluminum was used in a stainless steel bubbler as a pre-material for the baling. The carrier gas was bubbled into the trimethylaluminum liquid to form a carrier gas containing trimethylaluminum vaporized. The carrier gas containing vaporized trimethylaluminum was fed through a feed tube into a quartz glass reaction tube. Oxygen gas diluted with Ty-Pella was introduced into the fluidized bed through the openings in the orifices of the variable stirrer arm. The variable agitator was operated at 60 cycles per minute.

The bubbler and the nitrogen gas pipe leading to the bubbler were both heated to a temperature of 30 ° C and kept at that temperature. The tube leading from the bubbler to the bottom of the quartz glass reaction tube was heated to a temperature of about 45 ° C and kept there at a temperature.

The sintered region of the reaction tube was maintained at a temperature of about 60-150 ° C; the oxidizing gas injection site 20 located above the vSrahtelevS plate was heated to and maintained at about 400 ° C and the area above the oxidizing gas core was heated to about 550 ° C and maintained there.

.25 A stream of nitrogen at a rate of about 200 cm 3 / min was introduced into the bubbler and the nitrogen gas containing vaporized trimethylaluminum was introduced into the reaction tube by means of a nitrogen carrier gas at a flow rate of about 450 cm 3 / min. A stream of oxygen gas diluted with nitrogen gas was introduced into the reaction tube through a second core tube. The oxygen flow rate was about 496 cm 3 / min and the nitrogen flow rate was about 50 cm 3 / min.

An oxygen to ratio ratio of about 200: 1 to trimethylaluminum was maintained during this reaction to give a colorless white base mass.

• · 24 92443

The procedure was continued for 12 hours and an alumina coating with a thickness of about 300 x 10.10 m was formed on the phosphor component.

According to this example, electron microscopic examination of the baled phosphor-5 particles showed a smooth and angular alumina coating formed on the portions of the cold white alkaline earth metal halophosphate phosphor. In the example, the continuous and angular nature of the coating applied to the phosphor components was demonstrated by the repetition of the microscopic features of the loi-10 stent substrate. However, the microscopic features of the coated particle were clearly less pronounced than the microscopic features of the uncoated particle.

A comparison was made between the particles of uncoated cold white parasitic-15 material, the parts of uncoated cold white phosphor mechanically mixed with 0.05% by weight of Aluminum Oxide C, and the particles of cold white phosphor material present on aluminum. using the method for 20 varying coating thicknesses, SEM micrographs.

Micrographs showed that if the thickness of the coating increases to 150 x 10'10 m, a more popular growth of the alumina coating is observed at the points of the phosphor components to which the Aluminum Oxide C particles are attached during the manufacture of the powder. This phenomenon becomes more and more visible as the thickness of the coating increases. The surface pattern also becomes much less clear as the thickness of the coating increases in a very high resolution (50,000-100,000x) SEM analysis.

Example 9 In this example, a powder of a cold white alkaline earth metal halophosphate phosphor with alumina was coated by the method of the present invention using the apparatus shown in Example 1. 200 grams of calcium halophosphate

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25,92443 powder (Cool White No. 4459, sold by the Chemical and Metallurgical Division of GTE Products Corporation, Towanda, Pennsylvania) without a fluidizing aid was added to a quartz glass reaction tube to form a fluorescent light layer.

5 Liquid trimethylaluminum was used in a stainless steel bubbler as a bale precursor material. The carrier gas was bubbled into the trimethylaluminum liquid to form a carrier gas containing trimethylaluminum vaporized. The vaporized carrier gas containing 10 trimethylaluminum was fed via a feed tube to a quartz glass reaction tube. Oxygen-diluted oxygen gas was fed to the fluidized bed through openings in the shaft of the variable mixer. The variable mixer was operated at 60 and 15 soos per minute.

The bubbler and the nitrogen gas pipe leading to the bubbler were both heated to a temperature of 30 ° C and kept at that temperature. The tube leading from the die to the bottom of the quartz glass reaction tube was heated to a temperature of 45 ° C and kept in this lamp room.

The sintered section of the reaction tube was annealed at a temperature of about 60-150 ° C; the oxidizing gas injection site located above the oscillating plate was heated (<· 25 to about 400 ° C and the sitS was kept at this temperature; and the area above the oxidizing gas intake was heated to about 550 ° C and kept at this temperature).

A stream of nitrogen gas at a rate of about 100 cm 3 / min was passed to a bubbler and nitrogen gas containing vaporized trimethylaluminum was fed to the reaction tube at a flow rate of about 450 cm 3 / min by means of a nitrogen gas carrier. Oxygen gas diluted with nitrogen gas was introduced into the reaction tube through a second inlet tube. The oxygen flow-35 rate was about 496 cm 3 / min and the nitrogen diluent was about 50 • · 26 92443 cm3 / xnin. An oxygen content ratio of about 200: 1 to trimethylaluminum was maintained during this reaction.

The procedure was continued for 6 1/2 hours and an alumina coating with a thickness of about 160 x 10 "10 m was formed on the phosphor particles.

Electron microscopic examination of the coated phosphor components of this example showed a uniform, angle-accurate alumina coating formed on the particles of the cold white alkaline earth metal halophosphate phosphor. In this example, the continuous and angular nature of the coating applied to the phosphor was demonstrated by the repetition of the microscopic features of the phosphor substrate. However, the microscopic features of the coated particle are clearly less pronounced than the microscopic features of the uncoated particle.

Auger analysis of the surface of the coated particle showed complete surface coverage.

However, it was found that the color of the phosphor components baled using a fluidizing aid was not completely white and showed a brightness halide. The poor color of the base mass is caused by a poor circulation of the precursor material through the layer, which in turn is caused by a layer expansion smaller than the maximum value in the absence of a fluidizing aid.

"25 The coating thickness reported in each of the above examples has been calculated using the following formula: grams Al 2 O 3 / hour coating / hour = -3 - = - 3.97 g Al 2 O 3 / cm x total surface area of the phosphor x layer female surface (g) 30 •

The performance of the phosphor component of the present invention having a continuous, protective alumina coating surrounding its outer surface is superior to that of the uncoated phosphor. This will improve performance

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92443 27 is shown in the following use examples in which the alumina-coated fluorescent component of the present invention is used in fluorescent lamps. Fluorescent lamps typically experience a gradual decrease in light output as operating hours increase. Numerous factors contribute to the decrease in light output when using the lamp. These factors include the deposition of impurities from the cathode; formation of various mercury compounds by bombardment of a phosphor with mercury atoms and ions; 10 changes in the phosphor itself; and changes in the glass shell, especially if exposed to ultraviolet radiation. The ability of these lamps to resist a decrease in light output is commonly referred to as luminous flux stability, which is measured as the ratio of the luminous intensity of a given time interval to the original luminous flux, expressed as a percentage.

Although the decrease in light output over time occurs in all fluorescent lamps, it causes greater friction in high-power and very high-power 1 shots than in normally loaded lamps and fluorescents, which are particularly susceptible to diffuse discharge in a difficult environment.

Although all of the above factors may be present to a greater or lesser extent in the reduction of light output, it is generally assumed that one of the main reasons for the decrease in light output during use is the formation of mercury compounds, especially on the surface of the phosphor coating.

These mercury compounds are believed to form an ultraviolet-absorbing film which prevents the parasitic-30 substance from being sufficiently excited by the rain caused by the mercury discharge to achieve maximum light output.

Several uses of alumina have been proposed to improve lamp performance. The use of such a case-35 involves the use of a layer of alumina on the inner surface of the lamp dome and the application of a phosphor to it. Another use is to apply a thin layer of alumina to the surface of the phosphor layer.

Although these procedures provide some advantages, it is assumed that further improvement of the luminous flux stability when using only one layer of roaterial material on the inner surface of the lamp housing is advantageous.

In the method of the present invention, to improve the light output stability of fluorescent lamps, a continuous alumina coating is deposited on individual portions of the fine phosphor powder of the fluorescent lamp one by one and continuously to form baled phosphor components. The inner surface of the fluorescent lamp dome is then coated with one or more layers of fluorescent material. 15 Each layer of phosphor applied to the dome contains at least one phosphor component. A phosphor containing more than one phosphor component is more commonly referred to as a phosphor mixture. At least one of the phosphor layers applied to the lamp dome contains 20 phosphor components consisting of individually and continuously baled phosphor components. The coated dome is then processed into a finished lamp according to known methods. In those lamps which contain more than one phosphor layer, the layer containing the individually and continuously coated phosphor components is preferably the last phosphor layer applied to the lamp dome, i. a layer directly adjacent to the light arc-forming selector in the lamp.

As used herein, the term "continuous" refers to 30 non-fines, i.e. surrounding each phosphor component: the alumina coating does not consist of individual alumina components.

The main characteristics of the alumina-coated phosphor components of the present invention are: 35 (1) the continuous, non-continuous

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92443 29-part nature; (2) the angularly accurate nature of the baling, which reproduces the microscopic features naturally present on the non-balancing phosphor components; and (3) each phosphor component is individually påallystet-5 ty.

The main properties of the phosphor components of the present invention are determined and can be confirmed by scanning electron microscopy (SEM), Auger analysis, reflective electron diffraction and BET measurements.

Scanning electron microscopic examination of the coated particles shows that the particles are individually palletized, that the aluminum pellet on the phosphor component is continuous and does not consist of alumina particles, and that the pellet is angularly accurate and reproduces the microscopic features of the phosphor component below.

Auger analysis shows that the bale layer forms a substantially complete coverage of the outer surface of the phosphor components.

The hi electron diffraction fraction shows that the alumina pellet is continuous and non-crystalline, i. amorphous-sen.

BET measurements confirm that the alumina bale is angularly accurate and continuous in nature • 25 m, so that the surface area of the coated phosphor does not change significantly compared to the surface area of the uncoated phosphor. If the pSM coating were fine in nature, the surface area of the baled phosphor would increase considerably. BET measurements also confirm that the fluorescent-30 components are individually baled.

The fluorescent material of a fluorescent lamp comprises any material that fluoresces under the influence of ultraviolet rain. Examples of such fluorescent materials include, but are not limited to, alkaline earth metal halophosphate-35 phosphor phosphor and manganese doped zinc orthosilate phosphor.

30 92443

In a preferred embodiment, the continuous alumina dipally layer is deposited by chemical vapor deposition in a fluidized bed, e.g., a precursor material containing aluminum is deposited on the outer surface of the phosphor powder Examples of suitable precursors for aluminum-containing compounds include alkylaluminum compounds, aluminumalkoxide oxides and aluminumacetylacetonates.

In a preferred embodiment, the fluidized bed is formed by passing an inert gas through the phosphor particles to suspend the particles in an inert gas stream. Examples of suitable inert gases for use in this process include nitrogen, argon, helium, neon, and mixtures thereof. In addition to keeping the phosphor particles in the fluidized bed, the inert gas acts as a carrier gas. The pMallyste precursor material containing volatile aluminum is vaporized in an inert gas before it is introduced into the reaction chamber in which the phosphor components are suspended. Preferably, the carrier gas is saturated with steam from the precursor material of the aluminum-containing bale. As the carrier gas containing the bale precursor material containing vaporized aluminum moves up through the spheres of fluorescent particles to suspend the particles in the fluidized bed, the particles are covered by the carrier gas containing the bale precursor material.

Preferably, the suspended particles are exposed to the bale precursor material containing vaporized aluminum in a first temperature state lower than the iam-pd state in which the precursor material disperses. When the precursor material surrounds the particles, the precursor material is reacted to form a continuous allurine oxide patch on the surface of the individual particles in a second temperature state 35 or higher than the lamp state in which the precursor material reacts to form alumina.

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92443 31

The fluidized bed is most preferably maintained with a temperature gradient ranging from the lowest to the highest temperature. The lowest temperature must be lower than the temperature in which the precursor material of the bale 5 decomposes, while the highest temperature must be equal to or higher than the temperature in which the precursor material of the bale reacts to form the desired alumina precursor material.

If necessary, an oxidizing gas is introduced into the fluidized bed 10 separately from the carrier gas containing the vaporized bale precursor material. The use of oxidizing gas is optional if an oxygen-containing precursor material is used. Examples of suitable oxidizing gases are air and oxygen. The oxidizing gas can be mixed with 15 diluting inert gases.

The thickness of the bale depends on the time used for the procedure, the temperature of the evaporation source and the flow rate across the evaporation source, as well as the surface area of the phosphor. The process is continued long enough to form a continuous alumina coating of a predetermined thickness on the outer surface of the individual phosphor components.

One or more layers of fluorescent material are applied to the inner surface of the fluorescent lamp dome. At least one of the phosphor layers applied to the lamp image comprises a phosphor component consisting of individually and continuously coated phosphor components. The dome coated with the phosphor is then formed into a finished lamp according to known methods.

As used herein, the term "fluorescent lamp" refers to any lamp that contains a fluorescent material that fluoresces under the influence of ultraviolet radiation, regardless of its structure.

Referring now to Figure 35 in more detail, Figure 2 shows an example of a fluorescent lamp 92443 32 24 comprising a tubular, hermetically sealed glass dome 25. Electrodes 26 and 27 are attached to the ends of the dome 25. Electrodes 26 and 27 extend beyond the dome 25. An arc-forming and maintenance medium, such as one or more inert gases and mercury vapor, is added to the dome 25.

The phosphor bale 30 is applied to the inner surface of the dome 25. The coating 30 comprises a layer of fluorescent material consisting of finely divided portions of the fluorescent lamp fluorescent material 10, each of which is separately baled with a continuous alumina coating. Although the fluorescent lamp fluorescent material may be any material used in fluorescent lamps, the present invention is particularly effective if the fluorescent powder is a powder of alkaline earth metal halide phosphate or a manganese-doped zinc orthosilicate fluorescent powder.

The following examples of use are intended to explain to those skilled in the art the present invention and its application, and to further illustrate the various advantages of the present invention.

The phosphor numbers given in the illustrative examples below are key figures used by GTE Products Corporation, Towanda, Pennsylvania, from which the phosphor was obtained.

25 USE EXAMPLE 1

Individually and continuously coated phosphor particles prepared according to Example 1 are applied to the dome of a fluorescent lamp and a final lamp was prepared therefrom according to known methods. 30 steps for slurrying the phosphor into an organic solvent containing 1% by weight of Aluminum Oxide C using conventional mark screening.

Example 2 Uncoated calcium halophosphate particles (Cool 35 White No. 4459, lot 795) were mixed with 0.05% by weight of Aluminum Oxide C and the mixture was applied to a fluorescent lamp dome and treated according to methods known as finished lamps. than the use example cat 1.

5 Example 3 Uncoated calcium halophosphate particles (Cool White No. 4459, era 795) were applied to a fluorescent lamp dome and treated as a finished lamp according to known procedures, which were the same as in Example 1.

10 Use example 4

The calcium halophosphate particle (Cool White No. 4459, era 795) was coated with a continuous alumina pipette as shown in Example 1. The coated phosphor component was applied to the lamp dome as an aqueous suspension containing 1.75% by weight of Aluminum Oxide C and treated as a finished lamp according to known methods. The phosphor was not ground during the manufacturing process.

Use Example 5 A lamp was prepared according to Use Example 4 using weak grinding as an additional step.

The light output of the phosphor and its stability values for the standard according to use examples 1-5! For 4 Foot T-12 (40 watts) cold white fluorescent lamps, a flat -... 25 in size I is shown.

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II

92443 35

As can be seen from Table I, although the light output of the uncoated phosphor at 0 hours is increased, the light output stability of the phosphor components having a continuous alumina coating is improved compared to the uncoated phosphor components.

The effect of the fluorescent baling on the light output stability of the fluorescent lamp was further investigated in the following examples using a standard 4 Foot T12 VHO (very high output power) lamp.

10 Sample Example 6

Uncoated calcium halophosphate particles (Cool White No. 4459, era 501) were applied to the lamp dome as an aqueous suspension and processed into a finished lamp by known methods.

15 Sample Example 7

The calcium halophosphate particle (Cool White No. 4459, era 501) was coated with a continuous alumina coating as shown in Example 1. The baled phosphor components were applied to the lamp dome as an aqueous suspension 20 and processed into a finished lamp according to known methods. The phosphor was not ground during the manufacturing process.

The values of the light output of the phosphor and its stability for the 4 Foot T-12 VHO cold white * 25 fluorescent lamps used in Examples 6 and 7 are shown in Table II.

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As can be seen from Tables I and II, although the uncoated phosphor is initially brighter, the light output of the uncoated phosphor decreases faster as a function of time than the light output of the coated phosphor of the present invention. The ability of lamps with a coated fluorescent material to resist the dispersion of the fluorescent material is also demonstrated during the heat treatment in the oven during the lamp manufacturing stage.

The effect of alumina coating thickness on the light output stability of a parasitic-10 roller lamp was investigated using a standard 4 Foot T-14 VHO lamp.

Control Example 8 In this example, uncoated particles of cold white alkaline earth metal phosphate powder (Cool White No. 15 4459, lot 769) were applied to the inside of the lamp dome by injection of the following: according to known procedures: a Aluminum Oxide C, and for normal wet screening.

Control Example 9 In this example, particles of a cold white alkaline earth metal phosphate powder were individually coated with a continuous alumina coating using the apparatus shown in Example 1. 300 grams of 25 calcium halophosphate phosphor powder (Cool White No. 4459, lot 769) and 0.15 grams (0.05% by weight) of Aluminum Oxide C, sold by Degussa, Inc., as a fluidizing aid, were mixed together in a dry polyethylene container. to obtain a uniform dispersion containing Alumi-30 num Oxide C fluidizing aid evenly distributed in the alkaline earth metal halophosphate powder. A mixture of the halophosphate phosphor powder and the fluidizing aid was added to a quartz glass reaction tube to form a phosphor layer. Liquid trimethylaluminum was used in 35 stainless steel bubblers as a precursor material for the coating. The carrier gas was bubbled into the trimethylaluminum liquid to form a carrier gas containing trimethylaluminum vaporized. Hoyrys-damped trimethylaluminum was fed via a feed tube into 5 quartz glass reaction tubes. Oxygen-diluted oxygen gas was introduced into the fluidized bed through openings in the shaft of the oscillating mixer. The oscillating mixer was operated at 60 cycles per minute.

The bubbler and the nitrogen-10 gas tube leading to the bubbler were both heated to a temperature of 30 ° C and kept at that temperature. The tube leading from the bubbler to the bottom of the quartz glass reaction tube was heated to a temperature of about 45 ° C and kept there.

The sintered section of the reaction tube was maintained at a temperature of about 60-150 ° C; the oxidizing gas inlet located above the oscillating plate was heated to and maintained at a temperature of about 400 ° C, and the area 20 above the oxidizing gas inlet was heated to about 550 ° C and maintained at that temperature.

A stream of nitrogen of about 100 cm 3 / min was passed to a bubbler and nitrogen gas containing vaporized trimethylaluminum was injected with nitrogen carrier gas into 25 reaction tubes at a rate of about 550 cm 3 / min. Oxygen-diluted oxygen gas was introduced into the reaction tube through a second inlet tube. The oxygen flow rate was 495 cm 3 / min and the nitrogen diluent was about 50 cm 3 / min. An oxygen content to trimethylaluminum ratio of about 200: 1 was maintained during this reaction to give a white color to the base mass.

The procedure was continued for 6 hours and an alumina coating with a thickness of about 100 x 10.10 m was formed on the phosphor component.

II

92443 39

Electron microscopic examination of the baled phosphor components of this example showed a uniform angular-accurate alumina coating formed on the cold white alkaline earth metal halophosphate fluorescent components. In the example, the nature of the continuous and angular coating applied to the phosphor components was demonstrated by repeating the microscopic features of the phosphor substrate. However, the microscopic features of the baled particle were clearly less pronounced than the microscopic features of the uncoated particle-10 particle.

The baled phosphor components were applied to the inside of the lamp dome according to known methods, including the steps of slurrying the baled phosphor into an aqueous suspension containing 1.75% by weight of Aluminum Oxi-15 de C and performing normal mark screening.

KTyto Example 10

In this example, particles of a cold white alkaline earth metal phosphate powder were palletized with a continuous alumina coating using the apparatus shown in Example 1. 300 grams of calcium halophosphate phosphor powder (Cool White No. 4459, era 769) and 0.15 grams (0.05% by weight) of Aluminum Oxide C fluidizing aid, sold by Degussa Inc., were mixed together in a dry polyethylene vessel to form a uniform dispersion. containing Aluminum Oxide C fluidizing aid evenly distributed in the alkaline earth metal halophosphate powder. A mixture of halophosphate powder and Lei floating aid was added to a quartz glass reaction tube to form a phosphor layer. Liquid tri-30 methylaluminum was used in a stainless steel bubbler as a precursor material for the baling. The carrier gas was bubbled to form a carrier gas containing vaporized trimethylaluminum. The carrier gas containing vaporized trimethylaluminum was fed via a feed tube to a quartz glass reaction tube.

92443 40

Oxygen-diluted oxygen gas was introduced into the fluidized bed through openings in the shaft of the variable agitator. The variable agitator was operated at 60 cycles per minute.

5 The bubbler and the nitrogen gas pipe leading to the bubbler were both heated to a temperature of 30 ° C and kept at this temperature. The tube leading from the bubbler to the bottom of the quartz glass reaction vessel was heated to a temperature of about 45 ° C and kept at that temperature.

The sintered section of the reaction tube was maintained at a temperature of about 60-150 ° C; the oxidizing gas inlet located above the alternating plate was heated to and maintained at a temperature of about 400 ° C and the area above the bleed gas inlet was heated to and maintained at a temperature of about 550 ° C.

A nitrogen stream of about 150 cm 3 / min was introduced into the bubbler and nitrogen gas containing vaporized trimethylaluminum was fed to the reaction tube at a flow rate of about 500 cm 3 / min by means of a nitrogen carrier gas. Oxygen gas diluted with nitrogen gas was introduced into the reaction tube through a second inlet tube. The oxygen flow rate was about 495 cm 3 / min and the nitrogen diluent about 50 cm 3 / min. An oxygen content ratio of about 25,200: 1 to trimethylaluminum was maintained during this reaction to obtain a white color in the base mass.

The procedure was continued for 4 hours and an alumina bale with a thickness of about 100 x 10.10 m was formed on the phosphor component.

Electron microscopic examination of the polished phosphor components of this example showed a uniform, angular-accurate alumina coil formed on the particles of the cold white alkaline earth metal halophosphate phosphor 35. In the example, the continuous and angular nature of the coating applied to the phosphor components could be demonstrated by repeating the microscopic features of the phosphor substrate. However, the xnicroscopic features of the coated particle were clearly less pronounced than the xnicroscopic features of the uncoated particle-5 particle.

The baled phosphor components were applied to the inner surface of the lamp dome according to known methods, including the steps of slurrying the baled phosphor into an aqueous suspension containing 1.75% by weight of Aluminum 10 Oxide C and performing normal wet screening.

Sample example 11

In this example, particles of a cold white alkaline earth metal phosphate powder were individually coated with a continuous alumina coating using the apparatus shown in Example 1. 300 grams of calcium halophosphate fluorescent powder (Cool White No. 4459, era 769) and 0.15 grams (0.05% by weight) of Aluminum Oxide C fluidizing aid, sold by Degussa, Inc., were mixed together in a dry polyethylene vessel to form a uniform dispersion. containing Aluminum Oxide C fluidizing aid evenly distributed in alkaline earth metal halophosphate powder. A mixture of the halophosphate phosphor powder and the fluidizing aid was added to a quartz glass reaction tube to form a phosphor layer. Liquid trimethylaluminum was used in a stainless steel bubbler as a pre-stage material for baling. The carrier gas was bubbled into the trimethylaluminum liquid to form a carrier gas containing vaporized trimethylaluminum. Evaporated 30 trimethylaluminum-containing carrier gas was fed through a core tube into a quartz glass reaction tube. Oxygen gas diluted with nitrogen was introduced into the fluidized bed through openings in the arm of the vibrating mixer. The variable mixer was operated at 60 to 35 cycles per minute.

92443 42

The bubbler and the nitrogen gas tube leading to the bubbler were both heated to a temperature of 30 ° C and maintained at that temperature. The tube leading from the bubbler to the bottom of the quartz glass reaction tube was heated to a temperature of about 45 ° C and maintained at that temperature.

The sintered section of the reaction tube was maintained at a temperature of about 60-150 ° C; the oxidizing gas inlet was heated to about 400 ° C and maintained at that temperature, and the area above the oxidizing gas inlet was heated to about 550 ° C and maintained at that temperature.

A nitrogen flow of about 100 cm 3 / min was passed to a bubbler and nitrogen gas containing vaporized trimethylaluminum-15 was fed to the reaction tube at a flow rate of about 550 cm 3 / min by means of a nitrogen carrier gas. A stream of oxygen gas diluted with nitrogen gas was introduced into the reaction tube through a second inlet tube. The oxygen flow rate was about 495 cm 3 / min and the nitrogen diluent about 50 cm 3 / min. An oxygen content ratio of about 200: 1 to trimethylaluminum was maintained during this reaction to give a white color to the base mass.

The procedure was continued for 9 hours and an alumina coating with a thickness of * 25 of about 150 x 10.10 m was formed on the phosphor component.

Electron microscopic examination of the coated phosphor components of this example showed a uniform, angle-accurate alumina coating formed on the particles of the cold white alkaline earth metal halophosphate phosphor. In the example, the continuous and angular nature of the coating applied to the phosphor components was demonstrated by repeating the microscopic features of the phosphor substrate. However, the microscopic features of the coated particle were clearly less pronounced than the microscopic features of the uncoated particle.

92443 43 The coated phosphor component was applied to the inner surface of the laxnpu dome in accordance with known methods, including the steps of suspending the coated phosphor in an aqueous suspension containing 1.75% by weight of Alu-5 minum Oxide C and normal m.

Application Example 12 In this example, the particles of the cold white alkaline earth metal meat phosphate phosphor powder were coated individually with a continuous alumina coating using the apparatus shown in Example 1. 300 grams of calcium halophosphate fluorescent powder (Cool White No. 4459, era 769) and 0.15 grams (0.05% by weight) of Aluminum Oxide C fluidizing aid, supplied by Degussa, Inc., were mixed together in a dry polyethylene vessel to obtain a uniform dispersion, which contained Aluminum Oxide C lubricant excipient evenly distributed in the alkaline earth metal phosphate powder. A mixture of halophosphate fluorescent powder and fluidizing aid was added to a quartz glass reaction tube to form a phosphor layer. Liquid trimethylaluminum was used in a stainless steel bubbler as a precursor material for the coating. The carrier gas was bubbled into the trimethylaluminum liquid to form trimethylaluminum containing: 25 carrier gas. The vaporized trimethyl aluminum-containing carrier gas was passed through a feed tube to a quartz glass reaction vessel. Oxygen-diluted oxygen gas was introduced into the fluidized bed through openings in the shaft of the oscillating stirrer. Våråh-. 30 mixing mixers were operated at 60 cycles per minute.

The bubbling device and the nitrogen gas pipe leading to the bubbling device were heated to a temperature of 30 ° C and kept at this temperature. The tube leading from the bubbler to the bottom of the quartz-35 glass reaction tube was heated to a temperature of about 45 ° C and maintained at that temperature.

44 92443

The sintered section of the reaction tube was maintained at a temperature of about 60-150 ° C; the oxidizing gas inlet located above the alternating plate was heated to and maintained at a temperature of about 400 ° C, and the area above the oxidizing gas inlet was heated to about 550 ° C and maintained at that temperature.

A stream of nitrogen gas of about 150 cm 3 / min was introduced into the bubbler and nitrogen gas containing vaporized trimethylaluminum 10 was fed to the reaction tube by means of a nitrogen carrier gas at a flow rate of about 550 cm 3 / min. An oxygen stream diluted with nitrogen flash gas was introduced into the reaction tube through a second inlet tube. The oxygen flow rate was about 495 cm 3 / min and the nitrogen diluent about 50 cm 3 / min. An oxygen content ratio of about 15,200: 1 to trimethylaluminum was maintained during this reaction to obtain a white color in the base mass.

The procedure was continued for 9 hours and an alumina coating with a thickness of about 150 x 10.10 m was formed on the phosphor component.

Electron microscopic examination of the coated phosphor components of this example showed a smooth, angle-accurate alumina coating formed of cold white alkaline earth metal halophosphate phosphor: 25 particles. In the example, the continuous and angular nature of the coating applied to the phosphor components was demonstrated by the repetition of the microscopic features of the phosphor substrate. However, the microscopic features of the coated particle were clearly less pronounced than those of the uncoated particle. Microscopic features of 30 tomån particles.

The coated phosphor component was applied to the inner surface of the lamou dome according to known methods, including the steps of slurrying the coated phosphor into an aqueous suspension containing 1.75% by weight of Aluminum 35 Oxide C fluidization aid, as well as the normal amount.

II

45 92443 Example 13 In this example, particles of a cold white alkaline earth metal phosphate powder were individually individually coated with a continuous alumina coating 5 using the apparatus of Example 1. 300 grams of calcium halophosphate phosphor powder (Cool White No. 4459, era 769) and 0.15 grams (0.05% by weight) of Aluminum Oxide C fluidizing aid, supplied by Degussa, Inc., were mixed together in a dry polyethylene container with 10 uniform dispersions. containing Aluminum Oxide C fluidizing aid evenly distributed in the alkaline earth metal halophosphate powder. A mixture of halophosphate fluorescent powder and fluidizing aid was added to a quartz glass reaction tube to form a phosphor layer 15. Liquid trimethylaluminum was used in a stainless steel bubbler as a bale precursor material. The carrier gas was bubbled into the trimethylaluminum liquid to form a carrier gas containing trimethylaluminum. The carrier gas containing vaporized trimethylaluminum was introduced through a feed tube into a quartz glass reaction tube. Oxygen-diluted oxygen gas was fed to the fluidized bed through openings in the shaft of the variable agitator. The variable agitator was operated at 25 rpm for 60 cycles per minute.

The bubbler and the nitrogen-gas tube leading to the bubbler were both heated to a temperature of 30 ° C and kept at that temperature. The tube leading from the bubbler to the bottom of the quartz glass reaction tube was heated to a temperature of about 45 ° C and maintained at that temperature.

The sintered section of the reaction tube was maintained at a temperature of about 60-150 ° C; the oxidizing gas inlet located above the oscillating plate was heated to 35 and maintained at about 400 ° C, 46 92443 and the area above the oxidizing gas inlet was heated to about 550 ° C and maintained at that temperature.

A nitrogen flow of about 150 cm 3 / min was introduced into the bubbler and vaporized trimethylaluminum-containing nitrogen gas was introduced into the reaction tube by means of a nitrogen carrier gas at a flow rate of about 500 cm 3 / min. An oxygen stream diluted with nitrogen gas was introduced into the reaction tube through a second inlet tube. The oxygen flow rate was 495 10 cm 3 / min and the nitrogen diluent 50 cm 3 / min. An oxygen to ratio ratio of about 200: 1 to trimethylaluminum was maintained during this reaction to give a white color to the base mass.

The procedure was continued for 8 hours and an alumina bale with a thickness of about 200 x 10'10 m was formed on the phosphor component.

Electron microscopic examination of the coated phosphor components of this example showed a uniform, angular alumina coating formed on the cold white alkaline earth metal halophosphate phosphor particles. In the example, the continuous and angular nature of the coating applied to the phosphor components was demonstrated by the repetition of the microscopic features of the phosphor substrate. However, the microscopic features of the coated particle are clearly less pronounced than the microscopic features of the uncoated particle.

The coated phosphor components were applied to the inner surface of the lamp dome according to known methods, including the steps of slurrying the coated phosphor into an aqueous suspension containing 1.75% by weight of Aluminum.

Oxide C fluidization aid, and for normal wet screening.

Example 14 In this example, particles of a cold white alkaline earth metal-35 meat phosphate phosphor powder coating

II

47 92443 was individually coated with a continuous alumina coating using the apparatus shown in Example 1. 300 grams of calcium halophosphate fluorescent powder (Cool White No. 4459, era 769) and 0.15 grams (0.05% by weight) of Aluminum 5 Oxide C fluidizing aid, sold by Degussa, Inc., were mixed dry in a polyethylene vessel to obtain a uniform dispersion. which contained Aluminum Oxide C fluidizing aid evenly distributed in the halophosphate loose tea powder. A mixture of halophosphate fluorescent powder and fluidizing aid was added to a quartz glass reaction tube to form a phosphor layer. Liquid trimethylaluminum was used in a stainless steel bubbler as a bale precursor material. The carrier gas was bubbled into the trimethylaluminum liquid to form a carrier gas containing hoy-15 knurled trimethylaluminum. The carrier gas containing vaporized trimethylaluminum was fed through a feed tube into a quartz glass reaction tube. Oxygen-diluted oxygen gas was introduced into the fluidized bed through holes in the shaft of the variable se-20 stirrer. The variable agitator was operated at 60 rpm.

The bubbler and the nitrogen gas pipe leading to the bubbler were both heated to a temperature of 30 ° C and kept at that temperature. From the bubbler • The tube leading to the bottom of the 25 quartz glass reaction tubes was heated to a temperature of about 45 ° C and kept at that temperature.

The sintered section of the reaction tube was maintained at a temperature of 60-150 ° C; the oxidizing gas inlet located above the 30 volatile plates was heated to and maintained at 400 ° C and the area above the oxidizing gas inlet was heated to about 550 ° C and maintained there.

A stream of nitrogen of about 150 cm 3 / min was introduced into the bubbler and the nitrogen containing trimethylaluminum containing hydrogenated trimethylaluminum was fed to the reaction tube at a flow rate of about 500 cm 3 / min. A stream of oxygen gas diluted with nitrogen gas was introduced into the reaction tube through the second inlet tube. The oxygen flow rate was 495 cm 3 / min and the nitrogen diluent was about 50 cm 3 / min. An oxygen content to trimethylaluminum ratio of about 200: 1 was maintained during this reaction to obtain a white color in the base mass.

The procedure was continued for 12 hours and a phosphor component-10 was formed on it with a thickness of about 300 x 10 x 10 m.

Electron microscopic examination of the polarized phosphor particles of this example showed a uniform and angular alumina coil formed on the crystalline alkaline earth metal halophosphate phosphor particles. In the example, the continuous and angular nature of the Paal coating applied to the phosphor components was determined by repeating the microscopic features of the phosphor substrate. However, the microscopic features of the baled particle are clearly more pronounced than the microscopic features of the baled particle.

The coated phosphor component was applied to the inner surface of the lamp dome using known methods, including the steps of slurrying the coated phosphor into an aqueous suspension containing 1.75% by weight of Aluminum Oxide C fluidization aid and performing normal mark screening.

KTyto Example 15

In this example, the cold white alkaline earth metal. Particles of 30 meat phosphate phosphor powder were individually coated with a continuous alumina pallet using the apparatus shown in Example 1. 300 grams of calcium halophosphate fluorescent powder (Cool White No. 4459, erS 769) and 0.15 grams (0.15% by weight) of Aluminum 35 Oxide C fluidizing aid, supplied by Degussa, Inc., were mixed with each other when dry. in a polyethylene vessel to obtain a uniform dispersion containing Aluminum Oxide c lubricant excipient evenly distributed in alkaline earth metal phosphate powder. A mixture of a halophosphate phosphor and a fluidizing aid was added to a quartz glass reaction tube to form a phosphor layer. Liquid trimethylaluminum was used in a stainless steel bubbler as a bale precursor material. The carrier gas was bubbled into the trimethylaluminum-10 liquid to form a carrier gas containing trimethylaluminum. The carrier gas containing evaporated trimethylaluminum was introduced through a feed tube into a quartz glass reaction tube. Oxygen-diluted oxygen gas was introduced into the fluidized bed through openings in the shaft of the oscillating mixer 15. The variable agitator was operated at 60 cycles per minute.

The bubbler and the nitrogen gas tube leading to the bubbler were both heated to a temperature of 30 ° C and 20 were kept at this temperature. The tube leading from the bubbler to the bottom of the quartz glass reaction tube was heated to a temperature of about 45 ° C and kept there in the lamp6 state.

The sintered section of the reaction tube was maintained at 60-150 ° C in a lamp chamber; the oxidizing gas inlet located above the oscillating plate was heated to and maintained at about 400 ° C, and the area above the oxidizing gas inlet was heated to about 550 ° C and maintained at this temperature.

A nitrogen flow of about 200 cm 3 / min was passed through a bubbler and nitrogen gas containing vaporized trimethylaluminum was fed to the reaction tube at a flow rate of 450 cm 3 / min by means of a nitrogen carrier gas. A stream of oxygen gas diluted with nitrogen-35 gas was introduced into the reaction tube through a second inlet tube. The oxygen flow rate was about 496 cm 3 / min and the nitrogen diluent about 50 cm 3 / min. An oxygen content ratio of about 200: 1 to trimethylaluminum was maintained during this reaction to obtain a white color in the base mass.

The procedure was continued for 12 hours and an alumina coating with a thickness of about 300 x 10-10 m was formed on the phosphor particles.

Electron-10 microscopic examination of the baled particles of this example showed that a smooth, angular alumina coating had formed on the surface of the cold white alkaline earth metal halophosphate phosphor particles. In the example, the continuous and angular nature of the Paal coating applied to the phosphor component was demonstrated by repeating the microscopic features of the phosphor substrate. However, the microscopic features of the particle-free particle were clearly less pronounced than the microscopic features of the unpainted particle.

The coated phosphor component was applied to the inner surface of the dome of the lamp 20 according to known methods, including the steps of slurrying the coated phosphor into an aqueous suspension containing 1.75% by weight of Aluminum Oxide C and performing normal wet screening.

The values of the luminous efficacy and stability of the phosphor ‘25 standard 4 Foot T-12 VHO for cold white fluorescent lamps in Usage Examples 8-15 are shown in Table III. Although the values show a slight variation in the improvement in light output stability with thickness, an improvement in the light output stability of the 30 fluorescent lamps was obtained at all coating thicknesses studied.

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52 92443

The effect of the way in which the phosphor bale is prepared before it is applied to the inner surface of the lamp dome was investigated using a standard! 4 Foot T-12 VHO lamps. The results are shown in Table IV.

5 Sample Example 16

Uncoated particles of calcium halophosphate (Cool White No. 4459, era 501) were applied to the lamp dome in an aqueous suspension containing 1.75% by weight of Aluminum Oxide C and treated as a finished lamp according to known methods. The phosphor was ground slightly during the manufacturing process.

Sample Example 17

Particles of calcium halophosphate (Cool White No. 4495, era 501) were baled with a continuous alumina coating-15 tea 11a having a calculated thickness of 150 x 10 -10 m, as shown in Example 1. The coated phosphor components were applied to the lamp cap in an aqueous suspension containing 1.75% by weight of Aluminum Oxide C and treated as a finished lamp according to known procedures. Fluorescent-20 was not ground during the manufacturing process.

Example 18 18

A lamp was prepared according to Usage Example 17 using gentle grinding as an additional step.

Sample Example 19 Particles of calcium halophosphate (Cool White No. 4459, era 501) were baled on a continuous alumina coating with a calculated thickness of 150 x 10-10 m as shown in Example 1. The coated phosphor components were applied to the inner surface of the lamp dome according to known procedures, including the steps of slurrying the coated phosphor into an aqueous suspension containing 1.75% by weight of Aluminum Oxide C and performing a normal wet screen.

II

92443 53

Sample Example 20

Particles of calcium halophosphate (Cool White No. 4459, era 501) were coated with a continuous alumina coating having a calculated thickness of 150 x 10 -10 m, as shown in Example 1 of Example 5. The baled phosphor components were applied to the inner surface of the lamp dome according to known procedures, including the steps of slurrying the coated phosphor in an organic solvent containing 1% by weight of Aluminum Oxide C and performing a normal wet screen.

The luminous efficacy and stability values of the fluorescent material for the standard 4 Foot T-12 VHO prepared for cold white fluorescent lamps according to Usage Examples 16-20 are shown in Table IV. Although improvements are observed for all of the fabrication methods studied, the greatest improvement in light output stability when used alone and continuously baled phosphor components is observed in lamps made using mark screening. The values in Tables IV and I support the theory that grinding is detrimental to achieving optimal lamp performance when using Al 2 O 3 -painted phosphor components individually and continuously.

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11 92443 55

The effect of alumina-spun fluorescent components on the retention of the light output of the fluorescent lamp was further investigated using a 6 Foot T-12 HO (high power) standard lamp.

5 Sample example 21

Uncoated particles of calcium halophosphate (Cool White No. 4459, era 501) were applied to the lamp dome in aqueous suspension and treated as a finished lamp according to known procedures.

10 Use example 22

Particles of calcium halophosphate (Cool White No. 4459, lot 501) were baled on a continuous alumina coating as shown in Example 1. The baled phosphor component was applied to the lamp dome in an aqueous suspension and treated as a finished lamp according to known procedures. No phosphor was ground during the manufacturing process.

The values of the luminous efficacy of the phosphor and its stability 6 in the cold white fluorescent lamps according to Usage Examples 21-22 20 are shown in Table V.

92443 56

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X Φ> 92443 57 Reaction Example 23 In this example, particles of a green light emitting manganese-doped zinc orthosilicate fluorescent were individually coated with a continuous alumina coating-5 using the apparatus shown in Example 1. Manganese-doped zinc orthosilicate or willemite phosphor powder was screened through a mesn 400 mesh screen before being used in the present method to remove large agglomerates and particles. 300 grams of 10 screened manganese doped zinc orthosilicate phosphor powder (Sylvania type 2285) and 0.15 grams (0.05% by weight) of Aluminum Oxide C fluidizing aid, supplied by Degussa, Inc., were mixed dry in a polyethylene vessel to obtain a uniform dispersion. -15 si, which contained Aluminum Oxide C fluidizing aid evenly distributed in the phosphor powder. A mixture of the phosphor powder and the fluidizing aid was added to a quartz glass reaction tube to form a phosphor layer. Liquid trimethylaluminum was used in a 20 ° C stainless steel bubbler as a precursor material for the coating. The carrier gas was bubbled into trimethylaluminum liquid to form a carrier gas containing vaporized trimethylaluminum. The carrier gas containing vaporized trimethylaluminum was fed through a 25 inlet tube into a quartz glass reaction tube. Oxygen-diluted oxygen gas was fed to the fluidized bed through openings in the shaft of the oscillating mixer. The oscillating mixer was operated at 60 cycles per minute.

The bubbler and the nitrogen gas pipe leading to the bubbler were both heated to a temperature of 30 ° C and maintained at that temperature. The tube leading from the bubbler to the bottom of the quartz glass reaction tube was heated to a temperature of about 45 ° C and kept at this temperature-35.

58 92443

The sintered section of the reaction tube was maintained at a temperature of about 60-150 ° C; the oxidizing gas inlet above the oscillating plate was heated to about 400 ° C and maintained at that temperature, and the area above the oxidizing gas inlet was heated to about 550 ° C and maintained at that temperature.

A nitrogen stream of about 150 cm 3 / min was passed to a bubbler and nitrogen gas containing evaporated trimethylaluminum was fed to the reaction vessel with nitrogen carrier gas at a flow rate of about 500 cm 3 / min. A stream of oxygen gas diluted with nitrogen gas was passed through the second inlet of the reaction tube. The oxygen flow rate was about 500 cm 3 / min and the nitrogen diluent was about 50 cm 3 / min. An oxygen to trimethylaluminum ratio of about 15,200: 1 was maintained during this reaction to give a white color to the base mass.

The procedure was continued for 12 hours and an alumina coating with a thickness of about 250 x 10'10 m was formed on the phosphor component.

The alumina-coated particles of willemite were removed from the reaction tube.

Electron microscopic examination of the coated phosphor components of this example showed the formation of a uniform and high-grade alumina coating on the wille-mite phosphor components. In the example, the continuous and angular nature of the coating applied to the phosphor parts was demonstrated by the repetition of the microscopic features of the phosphor substrate. However, the microscopic features of the coated particle were clearly less ♦ • pronounced than the microscopic features of the uncoated particle.

Auger analysis of the surface of the coated particle showed that complete coating of the surface with alumina 35 had been achieved, an observation based on zinc, manganese

II

92443 59 and silicon in the fully attenuated coated wille mite compared to the uncoated willemite phosphor standard.

Individual and continuously coated phosphor-5 particles were then applied to the inner surface of the fluorescent lamp dome and a final 4 Foot-T 12 (40 watt) fluorescent lamp was prepared according to known methods, including the steps of slurrying the phosphor in an organic solvent containing 0.6% by weight: a Aluminum Oxide C, and 10 for normal wet screening. The phosphor was not ground during the manufacturing process. No Sb 2 O 3 was added to the slurry.

Reaction Example 24 Uncoated manganese-doped zinc or 15 tosilicate (Svlvania type 2285) particles were applied to the inner surface of a fluorescent lamp dome and a final 4 Foot-T12 (40 watt) fluorescent lamp was prepared by dissolving in an organic solvent, including the steps of a fluorescent solvent. % of Aluminum Oxide C, and for normal wet screening. The phosphor was not ground during manufacture. No Sk> 203 was added to the slurry.

Example 25

Uncoated particles of manganese doped zinc orthosilicate (Syl- "25 van type 2285) were applied to the inner surface of the fluorescent lamp dome and a final 4 Foot-T12 (40 watts) fluorescent lamp was prepared according to known methods, including steps to dissolve the phosphor in an organic solvent. % Aluminum Oxide C, and by gentle grinding: a phosphor during manufacture Antimony (III) oxide (Sk> 2203) was added to the coating suspension The Sb® addition used in the manufacture of the lamp is known to improve the vertical light output. .Butler, FLUORE-35 SCENT LAMP PHOSPHORS TECHNOLOGY AND THEORY, The Pennsylva- 60 92443 nia State University Press (University Park, Pa 1980), page 8. Sb203 lisays is an industry standard unless otherwise noted.

The luminosity and stability values of the phosphor for 4 Foot-T12 5 (40 watts) manganese doped zinc orthosilicate fluorescent lamps according to Examples 23-25 are shown in Table VI. An exceptional improvement in light output stability is observed in lamps using single and continuous Al 2 O 3 -coated, inangan-10 doped zinc orthosilicate fluorescent particles.

The thickness of the baler reported in each of the preceding use examples is calculated according to the following equation: 1

II

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62 92443

Although the presently preferred embodiment of the invention has been shown and described above, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the appended claims.

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II

Claims (10)

92443 A method for improving the light output stability of a fluorescent lamp, characterized in that it comprises the steps of a) depositing a continuous alumina coating on individual portions of the fine phosphor of the fluorescent lamp individually and continuously forming the fluorinated particles; B) applying one or more phosphor layers to the fluorescent lamp dome to form a phosphor-coated dome, wherein at least one phosphor layer has a phosphor component consisting of said individually and continuously expanded fluorescent components; and c) treating the dome corrugated with said fluorescent material into a finished lamp. A method according to claim 1, characterized in that the individual particles of fine fluorescent powder of the fluorescent lamp 20 are annealed by fluidizing the powder and spreading the continuous alumina coating on the individual particles by chemical hydride phase deposition. alumiinioksidipaailyste. Method according to Claim 1 or 2, characterized in that the fluorescent lamp is finely divided. The phosphor is an off-white alkaline earth metal halophosphate. Method according to Claim 1 or 2, characterized in that the fine phosphor of the fluorescent lamp is manganese-doped zinc orthosilicate. 92443 A method according to claim 2, characterized in that the suspended particles are exposed to the vaporized aluminum-containing precursor material in a first lamp state lower than the lamp state in which the precursor material disperses, and the precursor material is reacted to form a continuous alumina pair. in a lamp state higher than or equal to the lamp state in which the precursor material reacts to form alumina. 6. A fluorescent lamp comprising a glass dome having an inner surface, characterized in that the inner surface of the glass dome is annealed with one or more layers of fluorescent material, wherein at least one fluorescent layer has a phosphor component consisting of a fine fluorescent particulate particulate is individually bonded with a continuous alumina bonding gel. Fluorescent lamp according to Claim 6, characterized in that the continuous alumina coating is deposited by means of a chemical vapor deposition in a fluidized bed. Fluorescent lamp according to Claim 6 or 7, characterized in that the inner walls of the glass dome are coated with a fluorescent material consisting of finely divided phosphor particles of the fluorescent lamp, which are individually expanded by a continuous alumina pickling path. Fluorescent light lamp according to Claim 6, 7 or 8, characterized in that the finely divided phosphor of the fluorescent light lamp is a cold white alkaline earth metal halophosphate. Fluorescent lamp according to Claim 6, 7 or 8, characterized in that the fine phosphor of the fluorescent lamp 35 is a manganese-doped zinc orthosilicate fluorescent material. II 92443