US2010155761A1PendingUtilityA1

Light emitting device having a divalent europium-activated alkaline earth metal orthosilicate phoshor

Assignee: TOYODA GOSEI KKPriority: Dec 28, 2000Filed: Feb 23, 2010Published: Jun 24, 2010

Est. expiryDec 28, 2020(expired)· nominal 20-yr term from priority

Inventors:Koichi Ota Atsuo Hirano Akihito Ota Stefan Tasch Peter Pachler Gundula Roth Walter Tews Wofgang Kempfert Detlef Starick

H10W 72/552H10W 90/756H10W 90/736H10W 90/722H10W 90/00H10W 74/00H10W 72/07554H10W 72/5522H10W 72/884H10W 72/547G02B 6/0073B82Y 20/00F21Y 2115/10C09K 11/7795F21Y 2105/10C09K 11/774G02B 6/0036C09K 11/77344C09K 11/7734H10H 20/8515H10H 20/882H10H 20/825H10H 20/812H10H 20/8512Y02B20/00C09K 11/77

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Claims

Abstract

A light emitting device includes a light emitting element comprising a nitride semiconductor and a phosphor that can absorb a part of light emitted from the light emitting element and can emit light of a wavelength different from that of the absorbed light. The phosphor comprises a silicate phosphor comprising three alkali earth metals.

Claims

exact text as granted — not AI-modified

1 . A light emitting device, comprising:
 a light emitting element comprising a nitride semciconductor; and   a phosphor that can absorb a part of light emitted from said light emitting element and can emit light of a wavelength different from that of said absorbed light,   wherein said phosphor comprises a silicate phosphor comprising three alkali earth metals.   
     
     
         2 . The light emitting device according to  claim 1 , wherein said silicate phosphor comprises barium (Ba), calcium (Ca), and strontium (Sr). 
     
     
         3 . The light emitting device according to  claim 1 , wherein said silicate phosphor comprises a divalent-europium-activated alkaline earth metal silicate represented by a formula:
   (2-x-y)SrO.x(Ba,Ca)O.(1-a-b-c-d)SiO 2 . aP 2 O 5 bAl 2 O 3 cB 2 O 3 dGeO 2 :yEu 2+       where   0&lt;x&lt;1.6, 0.005&lt;y&lt;0.5, and 0&lt;a,b,c,and d &lt;0.5, and/or   a divalent-europium-activated alkaline earth metal silicate represented by a formula:
   (2-x-y)BaO.x(Sr,Ca)O.(1-a-b-c-d)SiO 2 .aP 2 O 5 bAl 2 O 3 cB 2 O 3 dGeO 2 :yEu 2+   
   where 
   0.01&lt;x&lt;1.6, 0.005&lt;y&lt;0.5, and 0&lt;a,b,c, and d&lt;0.5.   
     
     
         4 . The light emitting device according to  claim 1 , wherein said silicate phosphor emits a light with a half bandwidth up to 110 nm. 
     
     
         5 . The light emitting device according to  claim 1 , wherein said light emitting device emits white light. 
     
     
         6 . The light emitting device according to  claim 1 , wherein said light emitting element comprises a peak emission wavelength of 380 to 500 nm. 
     
     
         7 . The light emitting device according to  claim 1 , wherein a half-value width of a wavelength emitted from said light emitting element is not more than 500 nm. 
     
     
         8 . The light emitting device according of  claim 1 , wherein said nitride semiconductor comprises GaN-based semiconductor. 
     
     
         9 . The light emitting device according to  claim 1 , wherein said phosphor further comprises a different phosphor for emitting a red light. 
     
     
         10 . The light emitting device according to  claim 9 , wherein said different phosphor is selected from a group of an alkaline earth metal-magnesium-disilicate:Eu 2+ , Mn 2+  represented by a formula: Me (3-x-y) MgSi 2 O 3 :xEu, yMn where 0.005&lt;x&lt;0.5, 0.005&lt;y&lt;0.5, and Me comprises Ba and/or Sr and/or Ca.

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