Light emitting device

• US 10,559,725 B2
• Filed: 10/22/2018
• Issued: 02/11/2020
• Est. Priority Date: 05/26/2016
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Asai, Kenji
• Primary Examiner(s): Shamsuzzaman, Mohammed
• Application Number:
  US16/167,471
• Publication Number:
  US 20190067531A1
• Time in Patent Office: 477 Days
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/7707 Germanates
• CPC Class Codes: C09K 11/7721 Aluminates
• CPC Class Codes: C09K 11/7734 Aluminates
• CPC Class Codes: C09K 11/77342 Silicates
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: C09K 11/7739 with halogens
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H01L 33/52 Encapsulations

Abstract

A light emitting device includes a light emitting element having a peak emission wavelength of 410 nm to 440 nm and a phosphor member. The phosphor member includes a first phosphor having a peak emission wavelength of 430 nm to 500 nm and containing an alkaline-earth phosphate, a second phosphor having a peak emission wavelength of 440 nm to 550 nm and containing at least one of an alkaline-earth aluminate and a silicate containing Ca, Mg, and Cl, a third phosphor having a peak emission wavelength of 500 nm to 600 nm and containing a rare-earth aluminate, a fourth phosphor having a peak emission wavelength of 610 nm to 650 nm and containing a silicon nitride containing Al and at least one of Sr and Ca, and a fifth phosphor having a peak emission wavelength of 650 nm to 670 nm and containing a fluorogermanate.

Claims

1. A light emitting device comprising:

a light emitting element having a peak emission wavelength in a range of 410 nm to 440 nm; and

a phosphor member, the phosphor member containing a phosphor comprising;

a first phosphor having a peak emission wavelength in a range of 430 nm to 500 nm and containing an alkaline-earth phosphate, which includes Cl and is activated with Eu;

a second phosphor having a peak emission wavelength in a range of 440 nm to 550 nm and containing at least one of an alkaline-earth aluminate, which is activated with Eu, and a silicate, which includes Ca, Mg, and Cl and is activated with Eu;

a third phosphor having a peak emission wavelength in a range of 500 nm to 600 nm and containing a rare-earth aluminate, which is activated with Ce;

a fourth phosphor having a peak emission wavelength in a range of 610 nm to 650 nm and containing a silicon nitride, which includes Al and at least one of Sr and Ca and is activated with Eu; and

a fifth phosphor having a peak emission wavelength in a range of 650 nm to 670 nm and containing a fluorogermanate, which is activated with Mn, wherein a percentage content of the first phosphor to a total content of the phosphor is in a range of 20 mass % to 80 mass %, and wherein when the light emitting device is configured to emit light of correlated color temperature in a range of 5,500 K to 7,500 K, and a ratio of peak optical intensity of the first phosphor to the light emitting element is in a range of 0.4 to 1.5;

when the light emitting device is configured to emit light of correlated color temperature in a range of 4,500 K to 5,500 K, and a ratio of peak optical intensity of the first phosphor to the light emitting element is in a range of 0.4 to 1.5;

when the light emitting device is configured to emit light of correlated color temperature in a range of 3,500 K to 4,500 K, and a ratio of peak optical intensity of the first phosphor to the light emitting element is in a range of 0.3 to 1.3; and

when the light emitting device is configured to emit light of correlated color temperature in a range of 2,500 K to 3,500 K, and a ratio of peak optical intensity of the first phosphor to the light emitting element is in a range of 0.2 to 1.4;

wherein the light emitting device is configured to emit light with a sum of special color rendering Indices R9 to R15 of 600 or greater.

2. The light emitting device according to claim 1, wherein the light emitting device is configured to emit light of correlated color temperature in a range of 5,500 K to 7,500 K, and a percentage content of the first phosphor with respect to a total content of the phosphor is in a range of 30 mass % to 80 mass %.

3. The light emitting device according to claim 2, wherein a content ratio of the first phosphor with respect to the third phosphor is in a range of 0.9 to 6.

4. The light emitting device according to claim 1, wherein the light emitting device is configured to emit light of correlated color temperature in a range of 4,500 K to less than 5,500 K, and a percentage content of the first phosphor with respect to a total content of the phosphor is in a range of 30 mass % to 80 mass %.

5. The light emitting device according to claim 4, wherein a content ratio of the first phosphor with respect to the third phosphor is in a range of 0.8 to 5.5.

6. The light emitting device according to claim 1, wherein the light emitting device is configured to emit light of correlated color temperature in a range of 3,500 K to less than 4,500 K, and a percentage content of the first phosphor with respect to a total content of the phosphor is in a range of 20 mass % to 75 mass %.

7. The light emitting device according to claim 6, wherein a content ratio of the first phosphor with respect to the third phosphor is in a range of 0.6 to 4.2.

8. The light emitting device according to claim 1, wherein the light emitting device is configured to emit light of correlated color temperature in a range of 2,500 K to less than 3,500 K, and a percentage content of the first phosphor with respect to a total content of the phosphor is in a range of 40 mass % to 55 mass %.

9. The light emitting device according to claim 8, wherein a content ratio of the first phosphor with respect to the third phosphor is in a range of 1.9 to 2.5.

10. The light emitting device according to claim 1, wherein the alkaline-earth phosphate has a composition represented by formula (1):

(Ca,Sr,Ba)₅(PO₄)₃(Cl,Br);

Eu 

 

(1)

11. The light emitting device according to claim 1, wherein the alkaline-earth aluminate has a composition represented by formula (2a) and the silicate has a composition represented by formula (2b):

(Sr,Ca,Ba)₄Al₁₄O₂₅;

Eu 

 

(2a)

(Ca,Sr,Ba)₈MgSi₄O₁₆(F,Cl,Br)₂;

Eu 

 

(2b)

12. The light emitting device according to claim 1, wherein the rare-earth aluminate has a composition represented by formula (3):

(Y,Lu,Gd)₃(Al,Ga)₅O₁₂;

Ce 

 

(3)

13. The light emitting device according to claim 1, wherein the silicon nitride has a composition represented by formula (4):

(Sr,Ca)AlSiN₃;

Eu 

 

(4)

14. The light emitting device according to claim 1, wherein the fluorogermanate has a composition represented by formula (5a) or formula (5b):

3.5MgO.0.5MgF₂.GeO₂;

Mn 

 

(5a)

(x−

s)MgO.(s/2)Sc₂O₃.yMgF₂.cCaF₂.(1−

t)GeO₂.(t/2)M^t₂O₃;

zMn 

 

(5b)

wherein, M^t is at least one selected from the group consisting of Al, Ga, and In, and x, y, z, s, t, and u respectively satisfy 2.0≤

x≤

4.0, 0<

y<

1.5, 0<

z<

0.05, 0≤

s<

0.5, 0<

t<

0.5, and 0≤

u<

1.5.

15. The light emitting device according to claim 1, wherein the light emitting device is configured to emit light with a special color rendering Index R12 of 60 or greater.