# US 4,397,885 A · Method and apparatus for treating fluorescent substance

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- Number: US 4,397,885 A
- Document ID: US4397885A
- Status: Granted
- Kind: A
- Application number: 06/285,320
- Filed: 1981-07-22
- Granted: 1983-08-09
- Earliest claimed: 1980-08-22
- Assignees: Tokyo Shibaura Denki Kabushiki Kaisha
- Inventors: Yoshimi Akai; Akira Taya; Leo Mori; Kazuo Narita; Masahiko Hirose
- Web page: https://patentgrep.com/patent/US4397885A

## CPC

- H01J 37/32357: {Generation remote from the workpiece, e.g. down-stream}
- C09K 11/615: {Halogenides}
- C09K 11/642: {with zinc or cadmium}
- C09K 11/76: also containing phosphorus and halogen, e.g. halophosphates
- C09K 11/7789: {Oxysulfides}
- C09K 11/7795: {Phosphates}
- H05H 1/42: with provisions for introducing materials into the plasma, e.g. powder or liquid {(arc stabilising or constricting arrangements H05H1/3405; coaxial protecting fluids H05H1/341)}
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- H05H: PLASMA TECHNIQUE (apparatus or processes specially adapted for producing X-rays H05G2/00); PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS

## Abstract

A method and an apparatus for treating fluorescent substances used in illumination lamps or cathode ray tubes for television receivers. A gas plasma is produced by passing a gas through a discharge tube. The gas plasma including the active species are directed so as to bring the active species into contact with the fluorescent substance, the fluorescent substance being placed at a region separated from the plasma producing region.

## Claims

### Claim 1

A method for treating a fluorescent substance, said method comprising the steps of:
producing gas plasma in a first region; and
directing active species in the gas plasma to said fluorescent substance in a second region so as to bring the active species into contact with said fluorescent substance, said fluorescent substance in said second region being separated from said first region so as to be separated from ultraviolet radiation produced in said plasma producing step.

### Claim 2 (depends on 1)

A method according to claim 1, further comprising the step of stirring said fluorescent substance while in contact with said active species.

### Claim 3 (depends on 1)

A method according to claim 1, wherein said directing step comprises the step of directing said active species to said fluorescent substance while it is coated on a substrate.

### Claim 4 (depends on 2)

A method according to claim 2, wherein said stirring step comprises the step of rotating a cylindrical container about its axis, said container containing said fluorescent substance mixed with stir chips.

### Claim 5 (depends on 4)

A method according to claim 4, wherein said container and stir chips are made of quartz.

### Claim 6 (depends on 1)

A method according to claim 1, wherein said producing step comprises the step of producing a plasma from a gas selected from one of a first group consisting of Ar, He, Kr, Ne, Xe, H.sub.2, N.sub.2, O.sub.2 and methane halide, and a second group consisting of mixtures of at least two gasses in said first group.

### Claim 7 (depends on 6)

A method according to claim 6, wherein said producing step further comprises the step of producing a plasma from a mixture of N.sub.2 and H.sub.2.

### Claim 8 (depends on 6)

A method according to claim 6, wherein said producing step further comprises the step of producing a plasma from methane halide.

### Claim 9

An apparatus for treating a fluorescent substance comprising:
means for generating microwaves;
waveguide means, connected to said microwave generating means, for transmitting microwaves;
discharge means, crosswise penetrating said waveguide means, for producing a plasma therein;
gas supplying means, connected to one end of said discharge means, for supplying gas thereinto;
a treatment chamber connected to the other end of said discharge means, said fluorescent substance being disposed in said treatment chamber;
exhaust means, connected to the treatment chamber, for exhausting the gas therefrom;
a container rotatably supported in said treatment chamber for holding the fluorescent substance; and
means for rotating said container.

### Claim 10 (depends on 9)

An apparatus according to claim 9 wherein said container is cylindrical and further comprises a plurality of integral projections on an inside wall of said container.

### Claim 11 (depends on 9, 10)

An apparatus according to claim 9 or 10 further comprising stir chips disposed in said container together with a fluorescent substance.

### Claim 12 (depends on 11)

An apparatus according to claim 11 wherein said stir chips are made of quartz.