# US 6,720,026 B2 · Method for improving the optical separation of fluorescent layers

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- Number: US 6,720,026 B2
- Document ID: US6720026B2
- Status: Granted
- Kind: B2
- Application number: 09/764,950
- Filed: 2001-01-17
- Published: 2001-08-02
- Granted: 2004-04-13
- Earliest claimed: 2000-01-17
- Assignees: Siemens Aktiengesellschaft
- Inventors: Manfred Fuchs; Erich Hell; Detlef Mattern; Bernhard Schmitt
- Web page: https://patentgrep.com/patent/US6720026B2

## CPC

- C23C 14/0694: {Halides}
- H01J 9/221: {in continuous layers}
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

In a method for improving the optical separation of needle-shaped fluorescent layers, made from a fluorescent material, which are formed by vapor deposition on a substrate, vapor deposition is controlled so that the fluorescent layer is deposited on the substrate with a density which is reduced in comparison to the density that the fluorescent material has as a solid.

## Claims

### Claim 1

A method for forming fluorescent layers on a substrate, comprising the steps of:
vapor depositing a needle-shaped fluorescent layer having needle structures with voids therebetween, composed of fluorescent material, by producing a vapor jet of said fluorescent material onto a substrate in a vapor-deposition apparatus;
cooling said vapor jet before said vapor jet strikes said substrate by flowing cool inert gas through said vapor-deposition apparatus during the vapor depositing; and
controlling vapor deposition of said fluorescent layer so that said fluorescent layer is deposited on said substrate with lattice imperfections therein, giving said fluorescent it layer a density which is reduced, due to said voids and lattice imperfections, in comparison to a density which said fluorescent material has as a solid, to produce a needle-shaped fluorescent layer with optical separation between needle structures.

### Claim 2 (depends on 1)

A method as claimed in claim 1 comprising controlling said vapor deposition to reduce said density of the fluorescent layer by between 5% to 50% of said density that said fluorescent material has as a solid.

### Claim 3 (depends on 1)

A method as claimed in claim 1 comprising introducing said inert gas into said vapor deposition apparatus at a gas pressure below 10 Pa.

### Claim 4 (depends on 3)

A method as claimed in claim 3 comprising introducing said inert gas into said vapor-deposition apparatus at a pressure between 1 Pa and 3 Pa.

### Claim 5 (depends on 1)

A method as claimed in claim 1 comprising diverting said inert gas relative to said vapor jet with a baffle before introducing said inert gas into said vapor jet, causing said inert gas to be introduced indirectly into said vapor jet.

### Claim 6 (depends on 1)

A method as claimed in claim 1 comprising discharging said inert gas from said vapor-deposition apparatus with a pump.

### Claim 7 (depends on 1)

A method as claimed in claim 1 comprising introducing said inert gas into said vapor-deposition apparatus through a control valve.

### Claim 8 (depends on 1)

A method as claimed in claim 1 comprising conducting argon through said vapor-deposition apparatus as said inert gas.

### Claim 9 (depends on 1)

A method as claimed in claim 1 comprising introducing said inert gas at a temperature in a range between 0° C. and 100° C.

### Claim 10 (depends on 9)

A method as claimed in claim 9 comprising introducing said inert gas at approximately room temperature.

### Claim 11 (depends on 1)

A method as claimed in claim 1 comprising cooling said substrate during said vapor deposition.

### Claim 12 (depends on 11)

A method as claimed in claim 11 comprising maintaining said substrate at a temperature in a range between 50° C. and 200° C.

### Claim 13 (depends on 1)

A method as claimed in claim 1 comprising conducting said vapor-deposition at a rate greater than 1 mg cm−2min−1.