# US 2019/0375985 A1 · Hybrid fluorescent material and method of producing same

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- Number: US 2019/0375985 A1
- Document ID: US20190375985A1
- Status: Published application
- Kind: A1
- Application number: 16/549,298
- Filed: 2019-08-23
- Published: 2019-12-12
- Earliest claimed: 2015-12-09
- Assignees: Nichia Corporation
- Applicants: Nichia Corporation
- Inventors: Naoto FUJIOKA
- Web page: https://patentgrep.com/patent/US20190375985A1

## CPC

- C09K 11/7774: {Aluminates}
- B05D 1/18: performed by dipping
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02)

## Abstract

A method of producing hybrid fluorescent material includes dispersing Lu3Al5O12:Ce fluorescent material particles in a first solution; mixing the first solution in a second solution, the second solution including a mixture of a first metallic salt containing at least one element selected from the group consisting of yttrium, gadolinium, and terbium, a second metallic salt containing aluminum and/or gallium, and a third metallic salt containing cerium, wherein the mixing attaches (Y,Gd,Tb)3(Al,Ga)5O12:Ce fluorescent material precursor particles on surfaces of the Lu3Al5O12:Ce fluorescent material particles to obtain a hybrid fluorescent material precursor; separating the hybrid fluorescent material precursor particles from the first and second solutions; and calcining the hybrid fluorescent material precursor particles to obtain a hybrid fluorescent material of Lu3Al5O12:Ce fluorescent material particles covered by (Y,Gd,Tb)3(Al,Ga)5O12:Ce fluorescent material.

## Claims

### Claim 1

A method of producing a hybrid fluorescent material comprising:
(A) providing fluorescent material particles by heat treatment of a raw material mixture containing oxides or compounds convertible to the oxides by the heat treatment that contain lutetium (Lu), aluminum (Al), and cerium (Ce), wherein a temperature of the heat treatment is in a range of 1000° C. to 2100° C.,
(B) dispersing the fluorescent material particles obtained in (A) in a solution containing carbonate;
(C) providing a solution containing a mixture of a first metallic salt containing at least one element selected from the group consisting of yttrium, gadolinium, and terbium, a second metallic salt containing aluminum or gallium, and a third metallic salt containing cerium;
(D) mixing the solution obtained in (C) in the solution having the fluorescent material particles dispersed therein obtained in (B), to attach a fluorescent material precursor on surfaces of the fluorescent material particles obtained in (A), in order to obtain a hybrid fluorescent material precursor;
(E) separating the hybrid fluorescent material precursor from the solution; and
(F) calcining the hybrid fluorescent material precursor to obtain the hybrid fluorescent material in which the fluorescent material particles obtained in (A) are covered by a fluorescent material derived from the fluorescent material precursor attached to the surfaces on the fluorescent material particles in (D).

### Claim 2 (depends on 1)

The method of producing a hybrid fluorescent material according to claim 1, wherein in (C) a solution containing a mixture of a first metallic salt containing yttrium or gadolinium, a second metallic salt containing aluminum or gallium, and a third metallic salt containing cerium, is provided.

### Claim 3 (depends on 1)

The method of producing a hybrid fluorescent material according to claim 1, wherein in (C), a solution containing a mixture of a first metallic salt containing terbium, a second metallic salt containing aluminum, and a third metallic salt containing cerium is provided.

### Claim 4 (depends on 1)

The method of producing a hybrid fluorescent material according to claim 1, wherein in (C), the first metallic salt, the second metallic salt, and the third metallic salt are salts of at least one selected from the group consisting of nitrate, sulphate, and chloride.

### Claim 5 (depends on 1)

The method of producing a hybrid fluorescent material according to claim 1, wherein in (F), the calcining is performed in a reducing atmosphere.

### Claim 6 (depends on 1)

The method of producing a hybrid fluorescent material according to claim 1, wherein in (B), the carbonate is at least one carbonate selected from the group consisting of sodium carbonate, potassium carbonate, sodium hydrogen carbonate, ammonium hydrogen carbonate, and ammonium carbonate.

### Claim 7 (depends on 1)

The method of producing a hybrid fluorescent material according to claim 1, wherein (F) further comprises mixing a hybrid fluorescent material precursor and a flux.

### Claim 8 (depends on 7)

The method of producing a hybrid fluorescent material according to claim 7, wherein the flux is a fluorine compound.

### Claim 9 (depends on 1)

The method of producing a hybrid fluorescent material according to claim 1, wherein in (F), the calcining is carried out at a temperature in a range of 1,400° C. to 1,600° C.

### Claim 10 (depends on 1)

The method of producing a hybrid fluorescent material according to claim 1, wherein in (A), an average particle diameter of the fluorescent material particles is in a range of 5 μm to 25 μm.