White light emitting device

• US 7,227,190 B2
• Filed: 09/22/2003
• Issued: 06/05/2007
• Est. Priority Date: 09/30/2002
• Status: Expired due to Term

• Current Assignee: Leuchtstoffwerk Breitungen GmbH, Litec Gbr, Toyoda Gosei Company Limited (Toyota Motor Corporation), TridonicAtco Optoelectronics GmbH (Zumtobel Group AG)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Ota, Koichi, Shimonishi, Shota, Yasukawa, Takemasa
• Primary Examiner(s): Kebede; Brook
• Application Number:
  US10/529,254
• Publication Number:
  US 20050253158A1
• Time in Patent Office: 1,352 Days
• Field of Search: 257/13, 257/79, 257 80-101
• US Class Current: 257/79
• 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 is fixed onto lead frames in the cup of a frame using a mount, and the purple LED is sealed by filling a sealant of transparent resin into the cup. Red/green/blue phosphors that absorb a light emitted by the purple LED and emit lights having red, green, blue wavelengths different from the wavelength of this absorbed light are mixed into the sealant. A yellow phosphor that absorbs a light emitted by the purple LED and emits a light having a yellow wavelength different from the wavelength of this absorbed light is additionally mixed into the sealant in such a white light emitting device.

Claims

1. A white light emitting device, comprising:

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

a first phosphor to absorb a light emitted from the light emitting element and to emit a light comprising a yellow wavelength different from a wavelength of the light absorbed; and

a second phosphor comprising an emission wavelength different from at least that of the first phosphor, wherein the first phosphor comprises an alkaline earth metal silicate.

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

the emission wavelength comprises 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 comprising 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 to emit 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 comprises an alkaline earth metal silicate activated with europium.

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

the first phosphor comprises 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)SiO₂.aP₂O₅bAl₂O₃cB₂O₃dGeO₂;

y Eu²⁺

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)SiO₂.aP₂O₅bAl₂O₃cB₂O₃dGeO₂;

y Eu²⁺

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.

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

at least one of a red, green, blue yellow phosphor is mixed into a covering member covering the light emitting element.

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

the at least one red, green, blue and yellow phosphor to be mixed into the covering member is mixed into at the vicinity of the light emitting element in a high density condition.

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

the at least one red, green, blue and yellow phosphor is mixed in an insulative adhesive material for fixing the light emitting element to a lead frame.

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

the light emitting element is attached to a lead frame by a mounting material.

16. The white light emitting device as defined in claim 15, wherein:

the mounting material comprises the first phosphor and the second phosphor.

17. The white light emitting device as defined in claim 15, wherein:

an upper surface of the lead frame extends beyond a central portion of a bottom of a cup formed by a mount lead.

18. The white light emitting device as defined in claim 15, wherein:

the mounting material is previous to light emitted from the light emitting element.

10. A white light emitting device;

comprising;

a light emitting element comprising 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; and

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.

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

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

12. 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.

13. 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

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.

14. 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.