Led lighting source and led lighting apparatus

• US 20070023769A1
• Filed: 09/07/2004
• Published: 02/01/2007
• Est. Priority Date: 09/16/2003
• Status: Abandoned Application

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nagai, Hideo, Nishimoto, Keiji, Saito, Takeshi, Tanimoto, Noriyasu, Shimizu, Masanori
• Application Number:
  US10/569,360
• Publication Number:
  US 20070023769A1
• Time in Patent Office: Days
• US Class Current: 257/88
• 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: F21K 9/20 Light sources comprising attachment means
• CPC Class Codes: F21K 9/23 Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings
• CPC Class Codes: F21K 9/233 specially adapted for generating a spot light distribution, e.g. for substitution of reflector lamps
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• 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 33/641 characterized by the materials

Abstract

An LED lighting source preventing heat deterioration and improving luminous efficiency includes a mounting substrate having a wiring pattern on a first main surface thereof and a plurality of LED bare chips, each composed of a first semiconductor layer and a second semiconductor layer having respectively different conductivity, an active layer disposed therebetween, and a metal electrode on the first semiconductor layer and substantially equal in area thereto, and each LED bare chip being joined to the wiring pattern according to flip chip mounting of the metal electrode to form a junction between the wiring pattern and the metal electrode. Each junction is formed so that an area thereof is at least 20% of the area of the metal electrode. Thermal resistance from the active layers through to a second main surface of the mounting substrate, which is a back surface thereof, is set to 3.0 9C./W or lower.

Claims

1. An LED lighting source comprising:

a mounting substrate having a wiring pattern on a first main surface thereof; and

a plurality of LED bare chips, each composed of a first semiconductor layer and a second semiconductor layer that have respectively different conductivity, an active layer disposed between the first and second semiconductor layers, and a metal electrode disposed on the first semiconductor layer and being substantially equal in area to the first semiconductor layer, and each LED bare chip being joined to the wiring pattern according to flip chip mounting of the metal electrode to form a junction between the wiring pattern and the metal electrode,

wherein each junction is formed so that an area thereof is at least 20% of the area of the metal electrode, and

thermal resistance from the active layers through to a second main surface of the mounting substrate, which is a back surface thereof, is set to 3.0°

C./W or lower.

2. The LED lighting source of claim 1, wherein

at least the metal electrodes disposed on the first semiconductor layers and the wiring pattern are joined according to one of a gold-gold junction, a gold-aluminium junction, and a gold-tin junction.

3. The LED lighting source of claim 1, wherein

each junction between the metal electrodes disposed on the first semiconductor layer of each LED bare chip and the wiring pattern is made up of two or more bumps.

4. The LED lighting source of claim 1, wherein

each junction between the metal electrodes disposed on the first semiconductor layer of each LED bare chip and the wiring pattern is made up of two or more bumps that each have a diameter of at least 100 μ

m, or three or more bumps that each have a diameter of at least 80 μ

m.

5. The LED lighting source of claim 1, wherein

current density of the active layer of each LED bare chip during driving is in a range of 250 mA/mm² to 660 mA/mm² inclusive.

6. The LED lighting source of claim 1, wherein

the mounting substrate is composed of an insulation layer and a metal layer, the first main surface on which the wiring pattern is disposed being a main surface of the insulation layer, and the second main surface of the mounting substrate, which is an opposite surface to the surface on which the wiring pattern is disposed, being a surface of the metal layer.

7. The LED lighting source of claim 1, wherein

the mounting substrate includes an insulation layer that is composed of a composite material that includes an inorganic filler and a resin composite.

8. The LED lighting source of claim 1, wherein

the mounting layer includes an insulation layer that is composed of a ceramic material.

9. The LED lighting source of claim 1, wherein

the mounting substrate is composed of a ceramic material.

10. The LED lighting source of claim 9, wherein

the ceramic material includes at least one of AlN, Al₂O₃, and SiO₂.

11. An LED lighting apparatus comprising the LED lighting source of claim 1, wherein

the LED lighting apparatus includes a heats ink that is provided in close thermal contact with the back surface of the mounting substrate, and that has a thermal resistance of no less than 1.0°

C./W and no greater than 4.0°

C./W.

12. The LED lighting apparatus of claim 11, wherein

the heatsink is composed of at least one material chosen form the group consisting of Al, Cu, W, Mo, Si, AlN, and SiC.

13. An LED lighting apparatus comprising the LED lighting source of claim 1, wherein

the LED lighting apparatus includes a heats ink that is provided in close thermal contact with the back surface of the mounting substrate, and that has an enveloping volume of 100 cm³ to 820 cm³, inclusive.

14. The LED lighting apparatus of claim 13, wherein

the heatsink is composed of at least one material chosen form the group consisting of Al, Cu, W, Mo, Si, AlN, and SiC.

15. An LED lighting apparatus comprising the LED lighting source of claim 1, wherein

the LED bare chips are mounted to the mounting substrate by each LED bare chip being joined with a submount according to flip chip mounting, and each sub-mount being electrically joined with the wiring pattern on the first main surface of the mounting substrate.

16. An LED lighting apparatus comprising the LED lighting source of claim 15, wherein

the submounts and the mounting board are joined by conductive paste.

17. An LED lighting apparatus comprising the LED lighting source of claim 16, wherein

the conductive paste is composed of (i) at least one material selected from the group consisting of silver, copper, nickel, palladium, and tin;

or an alloy that includes one of the materials, and (ii) one of the materials mixed with resin.