White light emitting diode

• US 6,084,250 A
• Filed: 11/03/1998
• Issued: 07/04/2000
• Est. Priority Date: 03/03/1997
• Status: Expired due to Fees

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Ronda, Cees, Nikol, Hans, Justel, Thomas
• Primary Examiner(s): Tran, Minh Loan
• Application Number:
  US09/185,006
• Time in Patent Office: 609 Days
• Field of Search: 257/89, 257/98, 257/99, 257/100, 257/103, 313/502, 313/503, 313/504, 313/512
• US Class Current: 257/89
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials

Abstract

A light-emitting device comprising a UV-diode with a primary emission of 300 nm≦λ≦370 nm and a phosphor layer including a combination of a blue-emitting phosphor having an emission band, with 430 nm≦λ≦490 nm, a green-emitting phosphor having an emission band, with 520 nm≦λ≦570 nm and a red-emitting phosphor having an emission band, with 590 nm≦λ≦630 nm, emits high-quality white light. The color-rendering index CRI is approximately 90 at a color temperature of 4000 K. The color rendition depends only on the composition of the three phosphors, not on the relation between converted and non-converted light, and hence can be readily controlled and regulated.

Claims

1. A light-emitting device comprising an UV-diode with a primary emission of 300 nm≦

λ

≦

370 nm and exposed to said emission a phosphor layer comprising a blue-emitting phosphor having an emission band, with 430 nm≦

λ

≦

490 nm, a green-emitting phosphor having an emission band, with 520 nm≦

λ

≦

570 nm, and a red-emitting phosphor having an emission band, with 590 nm≦

λ

≦

630 nm.

2. A light-emitting device as claimed in claim 1, characterized in that the red-emitting phosphor is a emitter having an emission band with a wavelength maximum of 605 nm≦

λ

≦

620 nm.

3. A light-emitting device as claimed in claim 1, characterized in that the green-emitting phosphor is a emitter having an emission band with a wavelength maximum of 520 nm≦

λ

≦

570 nm.

4. A light-emitting device as claimed in claim 1, characterized in that the UV-diode is a GaN diode.

5. A light-emitting device as claimed in claim 1, characterized in that the phosphor layer comprises a blue-emitting phosphor in a quantity x1 of 0<

x1<

30% by weight, a green-emitting phosphor in a quantity x2 of 20≦

x2≦

50% by weight and a red-emitting phosphor in a quantity x3 of 30≦

x3≦

70% by weight.

6. A light-emitting device as claimed in claim 1, characterized in that the phosphor layer comprises BaMgAl₁₀ O₁₇ :

Eu as the blue-emitting phosphor, ZnS;

Cu as the green-emitting phosphor and Y₂ O₂ S as the red-emitting phosphor.

7. A light-emitting device as claimed in claim 1, characterized in that the phosphor layer comprises a phosphor of the general formula [Eu(diketonate)_a X_b1 X'"'"'_b2 ] as the red-emitting phosphor, wherein X=pyridine or a monodentate pyridine derivative and X'"'"'=2,2'"'"'-bipyridine or a 2,2'"'"'-bipyridyl derivative and 2a+b₁ +2b₂ =8.