Light emitting device

• US 8,546,824 B2
• Filed: 08/22/2011
• Issued: 10/01/2013
• Est. Priority Date: 09/06/2010
• Status: Active Grant

• Current Assignee: Alpad Corporation
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Mitsuishi, Iwao, Fukuda, Yumi, Okada, Aoi, Matsuda, Naotoshi, Nunoue, Shinya, Kato, Masahiro, Albessard, Keiko
• Primary Examiner(s): Mai, Anh
• Assistant Examiner(s): Breval, Elmito
• Application Number:
  US13/214,608
• Publication Number:
  US 20120056216A1
• Time in Patent Office: 771 Days
• Field of Search: 257/88, 257/E33.056, 257/E33.059, 257/E33.061, 257/89, 313484-487, 313/489, 313/498, 313/512, 313/467, 313/468, 313/499, 313501-503, 362/235, 362/227, 362/231, 362/293, 362/545, 362/800, 438/22, 438/26, 438/458, 345/44, 345/46
• US Class Current: 257/89
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: G09F 13/20 with luminescent surfaces or parts luminescent compositions C09K11/00; light sources using luminescence F21K2/00
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 33/502 Wavelength conversion materials

Abstract

A light emitting device according to one embodiment includes: a board; plural first light emitting units each including a first light emitting element and a first fluorescent layer formed on the first light emitting element having a green phosphor; plural second light emitting units each including a second light emitting element and a second fluorescent layer formed on the second light emitting element having a red phosphor; the second fluorescent layers and the first fluorescent layers being separated in a non-contact manner with gas interposed there between; and plural third light emitting units each including a third light emitting element and a resin layer formed on the third light emitting element having neither a green phosphor nor the red phosphor, the third light emitting units being disposed between the first light emitting units and the second light emitting units.

Claims

1. A light emitting device comprising:

a board;

a plurality of first light emitting units each of which includes a first light emitting element mounted on the board to emit light having a wavelength of 250 nm to 500 nm and a first fluorescent layer formed on the first light emitting element, the first fluorescent layer including a green phosphor;

a plurality of second light emitting units each of which includes a second light emitting element mounted on the board to emit the light having the wavelength of 250 nm to 500 nm and a second fluorescent layer formed on the second light emitting element, the second fluorescent layer including a red phosphor, the second fluorescent layers and the first fluorescent layers being separated in a non-contact manner with air interposed therebetween; and

a plurality of third light emitting units each of which includes a third light emitting element mounted on the board to emit the light having the wavelength of 250 nm to 500 nm and a resin layer formed on the third light emitting element, the resin layer including neither a green phosphor nor a red phosphor, the third light emitting units being disposed between the first light emitting units and the second light emitting units,

wherein the red phosphor has a composition expressed by equation (2);

(M′

<sub>1−

x2</sub>Eu_x2)_a1Si_b1AlO_c1N_d1 

 

(2)

(in the equation (2), M′

is an element selected from IA group elements, IIA group elements, IIIA group elements, IIIB group elements except Al (Aluminum), rare-earth elements, and IVB group elements, and x2, a1, b1, c1, and d1 satisfy the following relationship;

0<

x2<

1,

0.55<

a1<

0.95,

2.0<

b1<

3.9,

0<

c1<

0.6.

2. The device according to claim 1, wherein the third light emitting element is a blue LED.

3. The device according to claim 1, wherein the resin layer is made of a transparent resin.

4. The device according to claim 1, wherein the resin layer is made of a silicone resin.

5. The device according to claim 1, wherein the resin layer includes a yellow phosphor.

6. The device according to claim 1, wherein the first, second, and third light emitting elements are an identical kind of light emitting element.

7. The device according to claim 1, wherein the plurality of first light emitting units, the plurality of second light emitting units, and the plurality of third light emitting units are arrayed in column, respectively, and the column of the third light emitting units is disposed between the column of the first light emitting units and the column of the second light emitting units.

8. The device according to claim 1, wherein the plurality of second light emitting units are surrounded by the plurality of third light emitting units, and the plurality of third light emitting units are surrounded by the plurality of first light emitting units.

9. The device according to claim 1, wherein the plurality of first light emitting units are surrounded by the plurality of third light emitting units, and the plurality of third light emitting units are surrounded by the plurality of second light emitting units.