Semiconductor light emitting device

• US 20020097579A1
• Filed: 01/24/2001
• Published: 07/25/2002
• Est. Priority Date: 01/24/2001
• Status: Active Grant

• Current Assignee: Gelcore (General Electric Company)
• Original Assignee: Gelcore (General Electric Company)
• Inventors: Stalions, Drake Charles
• Granted Patent: US 6,940,704 B2
• Time in Patent Office: Days
• US Class Current: 362/241
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H01L 33/64 Heat extraction or cooling elements

Abstract

A light emitting diode (LED) including a combination of features that enable the LED to produce a high-brightness predetermined radiation pattern. The combination of features enable the LED to function cooler and more reliably at a higher drive currents and elevated ambient temperatures, and therefore emit light of increased brightness, without overheating, and to have a particular radiation pattern. In particular, a surface mount that is capable of operating at high drive currents and high ambient temperatures is disclosed. The LED comprises a surface mount package having a metal lead frame having mass sufficient to provide low thermal resistance, at least one anode contact pad and at least one cathode contact pad. The LED also includes a reflector positioned within the package, a semiconductor die and an optional focusing dome. The semiconductor die comprises a transparent substrate and a semiconductor component and is positioned within the package so that the semiconductor component and the substrate are arranged side-by-side over the reflector (flop-chip). Alternatively, the die is positioned within the package so that the substrate is on top of the semiconductor component (flip-chip). The optional focusing dome is operative to refract light emitted from the semiconductor die and light reflected from the reflector to create a predetermined radiation pattern.

Claims

1. A light emitting diode comprising:

a surface mount package;

a metal lead frame having mass sufficient to provide low thermal resistance and including at least one anode contact pad and at least one cathode contact pad;

a reflector positioned within the package; and

,

a semiconductor die comprising a transparent substrate and a light emitting component, the semiconductor die positioned within the package between an anode contact and a cathode contact over the reflector.

2. The light emitting diode of claim 1 further comprising a focusing dome operative to refract light emitted from the semiconductor die and light reflected from the reflector to create a predetermined radiation pattern.

3. The light emitting diode of claim 2 wherein the radiation pattern comprises a 120 degree illumination pattern.

4. The light emitting diode of claim 1 wherein the reflector comprises a truncated cone shape.

5. The light emitting diode of claim 1 wherein the lead frame comprises three anode contact pads and one cathode contact pad.

6. The light emitting diode of claim 1 wherein the lead frame comprises a lead frame having a thermal resistance less than 300 K°

/W.

7. The light emitting diode of claim 1 wherein the lead frame comprises copper.

8. The light emitting diode of claim 1 wherein the lead frame comprises silver-plated copper.

9. The light emitting diode of claim 1 wherein the light emitting component comprises a GaN-based compound semiconductor and the substrate comprises sapphire.

10. The light emitting diode of claim 1 wherein the light emitting component comprises an AlInGaP compound semiconductor and the substrate comprises GaP.

11. The light emitting diode of claim 1 wherein the light emitting component and the substrate are arranged side-by-side over the reflector.

12. The light emitting diode of claim 1 wherein the substrate is positioned on top of the light emitting component over the reflector.