Light emitting device and light emitter

• US 20080284315A1
• Filed: 04/15/2008
• Published: 11/20/2008
• Est. Priority Date: 04/16/2007
• Status: Active Grant

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Tasumi, Koji, Suehiro, Yoshinobu, Yamaguch, Seiji
• Granted Patent: US 7,872,410 B2
• Time in Patent Office: Days
• US Class Current: 313/503
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/003 Lens or lenticular sheet or layer
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02B 6/0083 Details of electrical connections of light sources to drivers, circuit boards, or the like
• CPC Class Codes: H01L 2224/0554 External layer
• CPC Class Codes: H01L 2224/0555 Shape
• CPC Class Codes: H01L 2224/0556 Disposition
• 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 2224/05599 Material
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• 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 33/501 characterised by the materials, e.g. binder

Abstract

A light emitting device includes a light emitting element, a substrate with a flat mounting surface for mounting the light emitting element thereon, a sealing part for the light emitting element on the mounting surface of the substrate. The sealing part is formed of glass including a phosphor to be excited by light emitted from the light emitting element to radiate a wavelength conversion light. The sealing part is shaped like a rectangular solid wherein a lateral length is defined as a distance between a center of a bottom surface of the sealing part bonded to the mounting surface and a side face perpendicular to the mounting surface, a vertical length is defined as a distance between the mounting surface and a top surface of the sealing part, and at least one of the lateral length is longer than the vertical length. The device further includes a transparent member formed on the top surface of the sealing part. The transparent member includes the phosphor at a concentration higher than the sealing part.

Claims

1. A light emitting device, comprising:

a light emitting element;

a substrate comprising a flat mounting surface for mounting the light emitting element thereon;

a sealing part for the light emitting element on the mounting surface of the substrate, the sealing part comprising glass including a phosphor to be excited by light emitted from the light emitting element to radiate a wavelength conversion light, the sealing part being shaped like a rectangular solid wherein a lateral length is defined as a distance between a center of a bottom surface of the sealing part bonded to the mounting surface and a side face perpendicular to the mounting surface, a vertical length is defined as a distance between the mounting surface and a top surface of the sealing part, and at least one of the lateral length is longer than the vertical length; and

a transparent member formed on the top surface of the sealing part, the transparent member including the phosphor at a concentration higher than the sealing part.

2. The light emitting device according to claim 1, wherein:

the transparent member comprises a vertical dimension thereof in a direction perpendicular to the mounting surface,

the vertical dimension is smaller than a difference between the lateral length and the vertical length, and

the light emitting element comprises a plurality of light emitting elements.

3. The light emitting device according to claim 2, wherein:

the substrate comprises a heat dissipation pattern on a back surface opposite the mounting surface, and

the light emitting device further comprises a heat dissipation member connected directly or indirectly to the heat dissipation pattern.

4. The light emitting device according to claim 3, wherein:

the transparent member comprises glass.

5. The light emitting device according to claim 4, wherein:

the transparent member further comprises inorganic paste.

6. The light emitting device according to claim 5, wherein:

the sealing part comprises the top surface and the bottom surface which are both shaped like a square, and

the two lateral lengths of the sealing part are equal to each other.

7. The light emitting device according to claim 6, wherein:

the sealing part comprises the top surface and the bottom surface which are both shaped like a rectangle with an elongated side in a direction, and

the sealing part further comprises a reflection member on the elongated side.

8. The light emitting device according to claim 4, wherein:

the transparent member further comprises resin.

9. The light emitting device according to claim 4, wherein:

the light emitting element is adapted to emit light with a wavelength not more than 410 nm, and

the phosphor is adapted to radiate blue, green and red lights as the wavelength conversion light.

10. The light emitting device according to claim 4, wherein:

the light emitting element is adapted to emit light in a blue region, and

the phosphor is adapted to radiate yellow light as the wavelength conversion light.

11. The light emitting device according to claim 4, wherein:

40% or more of the mounting surface of the substrate is covered with silver.

12. A light emitter, comprising:

the light emitting device according to claim 4; and

an emission surface to cause emission of light emitted from the light emitting device.