# US 10,312,417 B2 · Wavelength converted light emitting device

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- Number: US 10,312,417 B2
- Document ID: US10312417B2
- Status: Granted
- Kind: B2
- Application number: 15/538,162
- Filed: 2015-12-23
- Published: 2017-12-28
- Granted: 2019-06-04
- Earliest claimed: 2015-01-06
- Assignees: Koninklijke Philips N.V.
- Applicants: Koninklijke Philips N.V.
- Inventors: Gerd Mueller; Regina Mueller-Mach; Peter Josef Schmidt; Danielle Russell Chamberlin; Oleg Borisovich Shchekin; Hans-Helmut Bechtel
- Web page: https://patentgrep.com/patent/US10312417B2

## CPC

- H10H 20/8512: {Wavelength conversion materials}
- H10H 20/01: Manufacture or treatment
- H10H 20/824: comprising only Group III-V materials, e.g. GaP
- H10H 20/8513: {having two or more wavelength conversion materials}
- H10H 20/8514: {characterised by their shape, e.g. plate or foil}
- H10H 20/0361: {of wavelength conversion means}
- H10H 20/8516: {having a non-uniform spatial arrangement or non-uniform concentration, e.g. patterned wavelength conversion layer or wavelength conversion layer with a concentration gradient}
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS

## Abstract

In a method according to embodiments of the invention, for a predetermined amount of light produced by a light emitting diode and converted by a phosphor layer comprising a host material and a dopant, and for a predetermined maximum reduction in efficiency of the phosphor at increasing excitation density, a maximum dopant concentration of the phosphor layer is selected.

## Claims

### Claim 1

A method comprising:
providing a phosphor layer overlying a light emitting diode for converting a wavelength emitted by the light emitting diode to a longer wavelength, the step of depositing the phosphor layer comprising:
depositing a first region of the phosphor layer having a first dopant with a first dopant concentration, the first region emitting light of a first wavelength; and
depositing a second region of the phosphor layer adjacent to the first region, the second region having the first dopant with a second dopant concentration, wherein the second dopant concentration is less than the first dopant concentration, the second region also emitting light of the first wavelength,
wherein light emitted by the light emitting diode reaches the second region before the first region.

### Claim 2 (depends on 1)

The method of claim 1 wherein the first dopant concentration is uniform throughout the first region and the second dopant concentration is uniform throughout the second region.

### Claim 3 (depends on 1)

The method of claim 1 wherein the dopant concentration in the phosphor layer is graded.

### Claim 4 (depends on 1)

The method of claim 1 wherein the dopant in the first region and in the second region is Eu2+.

### Claim 5 (depends on 1)

The method of claim 1 wherein the dopant in the first region and in the second region is Ce3+.

### Claim 6

A structure comprising:
a light emitting diode emitting light having a first peak wavelength;
a phosphor layer disposed in a path of light emitted by the light emitting diode, the phosphor layer for absorbing light emitted by the light emitting diode and emitting light having a second peak wavelength; wherein the phosphor layer comprises a host material and a dopant, wherein the phosphor layer comprises:
a first region having a first dopant with a first dopant concentration, the first region emitting light having the second peak wavelength;
a second region having the first dopant with a second dopant concentration, wherein the second dopant concentration is less than the first dopant concentration, the second region also emitting light of the second peak wavelength; and
the first region and the second region are arranged such that light emitted by the light emitting diode reaches the second region before the first region.

### Claim 7 (depends on 6)

The structure of claim 6 wherein the first region is uniformly doped and the second region is uniformly doped.

### Claim 8 (depends on 6)

The structure of claim 6 wherein:
the second region is a layer proximate the light emitting diode;
the first region is a layer opposite the second region; and
the dopant concentration is graded between the second region and the first region.

### Claim 9 (depends on 6)

The structure of claim 6 wherein the dopant in the first region and in the second region is Eu2+.

### Claim 10 (depends on 6)

The structure of claim 6 wherein the dopant in the first region and in the second region is Ce3+.