White light emitting device

• US 20050253158A1
• Filed: 09/22/2003
• Published: 11/17/2005
• Est. Priority Date: 09/30/2002
• Status: Active Grant

• Current Assignee: Leuchtstoffwerk Breitungen GmbH, Litec Gbr, Toyoda Gosei Company Limited (Toyota Motor Corporation), Tridonic.Atco Optoelectronics GmbH
• Original Assignee: Tridonic.Atco Optoelectronics GmbH
• Inventors: Shomonishi, Shota, Ota, Koichi, Yasukawa, Takemasa
• Granted Patent: US 7,227,190 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: C09K 11/7731 with alkaline earth metals
• CPC Class Codes: C09K 11/77344 Aluminosilicates
• CPC Class Codes: C09K 11/7735 Germanates
• CPC Class Codes: C09K 11/7737 Phosphates
• CPC Class Codes: C09K 11/774 Borates
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/06102 the bonding areas being at different heights
• CPC Class Codes: H01L 2224/16145 the bodies being stacked
• CPC Class Codes: H01L 2224/1703 Bump connectors having different sizes, e.g. different diameters, heights or widths
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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
• CPC Class Codes: H01L 33/504 : Elements with two or more wavelength conversion materials
• CPC Class Codes: Y02B 20/00 : Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A purple LED (19) is fixed onto lead frames (14, 15) in the cup (17a) of a frame (17) using a mount (21), and the purple LED (19) is sealed by filling a sealant (26) of transparent resin into the cup (17a). Red/green/blue phosphors (28-30) that absorb a light emitted by the purple LED (19) and emit lights having red, green, blue wavelengths different from the wavelength of this absorbed light are mixed into the sealant (26). A yellow phosphor (31) that absorbs a light emitted by the purple LED (19) and emits a light having a yellow wavelength different from the wavelength of this absorbed light is additionally mixed into the sealant (26) in such a white light emitting device.

Claims

1. A white light emitting device, comprising:

a light emitting element having a peak wavelength of 500 nm or less;

a first phosphor absorbing a light emitted from the light emitting element and emitting a light having a yellow wavelength different from a wavelength of the light absorbed; and

a second phosphor having an emission wavelength different from at least that of the first phosphor.

2. The white light emitting device as defined in claim 1, wherein:

the emission wavelength is a peak wavelength of 400 nm or less.

3. The white light emitting device as defined in claim 1, wherein:

the second phosphor includes one or more of phosphors having blue through red emission wavelengths.

4. The white light emitting device as defined in claim 1, wherein:

the second phosphor includes any or all of phosphors emitting a blue light, a red light, and a green light, respectively.

5. The white light emitting device as defined in claim 1, wherein:

the first phosphor is an alkaline earth metal silicate.

6. The white light emitting device as defined in claim 1, wherein:

the first phosphor is an alkaline earth metal silicate activated with europium.

7. The white light emitting device as defined in claim 1, wherein:

the first phosphor is an alkaline earth metal orthosilicate activated with divalent europium represented by a formula;

(2-x-y)SrO.x(Ba, Ca)O.(1-a-b-c-d)SiO_2.aP₂O₅bAl₂O₃cB₂O₃dGeO₂;

yEu²⁺

wherein 0<

x<

1.6, 0.005<

y<

0.5, 0<

a, b, c, d<

0.5; and

/or an alkaline earth metal orthosilicate represented by a formula;

(2-x-y)BaO.x(Sr, Ca)O.(1-a-b-c-d)SiO₂aP₂O₅bAl₂O₃cB₂O₃dGeO₂;

yEu²⁺

wherein 0.01<

x<

1.6, 0.005<

y<

0.5, 0<

a, b, c, d<

0.5;

in this case, at least one of the values a, b, c, and d is advantageously more than 0.01.

8. The white light emitting device as defined in claim 1, wherein:

the red, green, blue and/or yellow phosphor(s) is (are) mixed into a covering member covering the light emitting element.

9. The white light emitting device as defined in claim 8, wherein:

the red, green, blue and/or yellow phosphor(s) to be mixed into the covering member is (are) mixed into at the vicinity of the light emitting element in a high density condition.

10. The white light emitting device as defined in claim 8, wherein:

the red, green, blue and/or yellow phosphor(s) is (are) further mixed also in an insulative adhesive material for fixing the light emitting element to a lead frame.

11. A white light emitting device;

comprising;

a light emitting element made of a GaN-based semiconductor and emitting a purple light which is disposed in a cup of a mount lead; and

a sealant made of a transparent resin filled in the cup and sealing the light emitting element;

red, green, and blue phosphors absorbing a light emitted from the light emitting element and emitting red, green, and blue lights of wavelengths different from that of the light absorbed, respectively, and a yellow phosphor absorbing a light emitted from the light emitting element and emitting a yellow light of a wavelength different from that of the light absorbed being mixed into the sealant.

12. The white light emitting device as defined in claim 11, wherein:

the white light emitting device comprises further a lens-shaped mold member made of a transparent resin and covering the cup filled with the sealant and a part of the mount lead.

13. A white light emitting device, comprising:

a light emitting element made of a GaN-based semiconductor and emitting a purple light which is disposed in a cup of a mount lead;

a sealant made of a transparent resin filled in the cup and sealing the light emitting element;

a lens-shaped mold member made of a transparent resin and covering the cup filled with the sealant and a part of the mount lead; and

a fluorescence cover fitted to the mold member and to which red, green, and blue phosphors absorbing a light emitted from the light emitting element and emitting red, green, and blue lights of wavelengths different from that of the light absorbed, respectively, are mixed into;

a yellow phosphor absorbing a light emitted from the light emitting element and emitting a yellow light of a wavelength different from that of the light absorbed is mixed into the fluorescence cover.

14. A white light emitting device, comprising:

a light emitting element emitting a purple light; and

a substantially rectangular light guidance plate guiding a light emitted from the light emitting element to outgo the light from a light-outgoing surface;

red, green, and blue phosphors absorbing a light emitted from the light emitting element and emitting red, green, and blue lights of wavelengths different from that of the light absorbed, respectively, and a yellow phosphor absorbing a light emitted from the light emitting element and emitting a yellow light of a wavelength different from that of the light absorbed being applied onto the light-outgoing surface of the light guidance plate.

15. A white light emitting device, comprising:

a light emitting element emitting a purple light;

a substantially rectangular light guidance plate guiding a light emitted from the light emitting element to outgo the light from a light-outgoing surface; and

a film to which red, green, and blue phosphors absorbing a light emitted from the light emitting element and emitting red, green, and blue lights of wavelengths different from that of the light absorbed, respectively, are mixed into;

a yellow phosphor absorbing a light emitted from the light emitting element and emitting a yellow light of a wavelength different from that of the light absorbed being mixed into the film.