Micro-LED based high voltage AC/DC indicator lamp

• US 7,535,028 B2
• Filed: 04/08/2005
• Issued: 05/19/2009
• Est. Priority Date: 02/03/2005
• Status: Active Grant

• Current Assignee: AC Led Lighting, LLC
• Original Assignee: AC Led Lighting, LLC
• Inventors: Jiang, Hongxing, Lin, Jingyu, Fan, Zhaoyang
• Primary Examiner(s): SEFER, AHMED N
• Application Number:
  US11/102,273
• Publication Number:
  US 20060169993A1
• Time in Patent Office: 1,502 Days
• Field of Search: 257 88- 89, 257/99, 438/22, 438/25
• 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: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 27/153 in a repetitive configuration, e.g. LED bars
• 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 2924/181 Encapsulation
• 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

Abstract

An AC/DC indicator lamp based on an array of micro-LEDs may be powered by a standard high voltage AC or DC power source. The indicator lamp has a low power consumption. The micro-LEDs are serially connected on a substrate with the total device area and power consumption compatible with a standard DC low voltage LED. A plurality of indicator lamps may be connected together in parallel to present a string of indicator lamps.

Claims

1. An AC/DC lamp comprising:

an integrated array of series connected micro-LEDs having a direction of current flow and presenting positive and negative terminals, each of said micro-LEDs having an active region between a p-type semiconductor and a n-type semiconductor,

said array of series connected micro-LEDs grown on a substrate,

said terminals adapted to be connected across a power source to energize said array of series connected micro-LEDs, and

said array being included in a package formerly designed for use for a standard-sized LED thus enabling said array to function as an indicator lamp.

2. The AC/DC lamp as set forth in claim 1 wherein said power source includes a power source selected from the group consisting of 12 volts DC, 24 volts DC, 36 volts DC, 48 volts DC, 110 volts AC, 120 volts AC, 220 volts AC and 240 volts AC.

3. The AC/DC lamp as set forth in claim 1 wherein said micro-LEDs are isolated from each other by etched trenches, and wherein said trenches are filled with polymer, oxides, nitrides or other insulation materials to achieve a generally flat top surface.

4. The AC/DC lamp as set forth in claim 1 wherein said micro-LEDs include etched trenches and sidewalls, said sidewalls coated with an insulation material.

5. The AC/DC lamp as set forth in claim 4 wherein said insulation material includes an insulation material selected from the group consisting of silicon oxide, silicon nitride, oxides, nitrides and polymides.

6. The AC/DC lamp as set forth in claim 4 wherein said sidewalls have a slope to enhance light extraction and conformal deposition of insulation material and interconnection metal wire.

7. The high voltage AC/DC lamp as set forth in claim 1 further comprising a second array of series connected micro-LEDs grown on said substrate and connected in series or parallel to said array of series connected micro-LEDs.

8. The high voltage AC/DC lamp as set forth in claim 1 wherein said substrate is an insulating substrate and includes a substrate material selected from the group consisting of sapphire, aluminum nitride, silicon carbide, silicon, gallium nitride, gallium arsenide and indium phosphide.

9. The AC/DC lamp as set forth in claim 1 wherein said substrate is a conducting or semi-conducting substrate and includes a substrate material selected from the group consisting of silicon carbide, silicon, gallium nitride, gallium arsenide and indium phosphide.

10. The AC/DC lamp as set forth in claim 1 further comprising an insulating layer between said substrate and said n-type semiconductor.

11. The AC/DC lamp as set forth in claim 10 wherein said insulating layer selected from the group consisting of aluminum nitride, aluminum gallium nitride, and aluminum indium gallium nitride.

12. The high AC/DC lamp as set forth in claim 10 further comprising a buffer layer between said insulating layer and said substrate.

13. The AC/DC lamp as set forth in claim 12 wherein said buffer layer has a thickness between 0 and 10 μ

m.

14. The AC/DC lamp as set forth in claim 1 wherein said micro-LEDs are based on semiconductors selected from the group consisting of AlInGaN, AlInGaP and AlGaAs.

15. The AC/DC lamp as set forth in claim 1 further comprising a package for housing said array.

16. The AC/DC lamp as set forth in claim 15 wherein said package includes a package selected from the group consisting of T1, T1-¾

and T3-¼

having lens size diameters of 3 mm, 5 mm, and 10 mm respectively.

17. The AC/DC lamp as set forth in claim 16 further comprising a plurality of said indicator lamps connected in parallel.

18. The AC/DC lamp as set forth in claim 17 wherein said indicator lamps emit the same or different colors.

19. The AC/DC lamp as set forth in claim 15 wherein said package is a surface mount package.

20. The AC/DC lamp as set forth in claim 1 wherein said array of micro-LEDs emit white light by wavelength conversion with phosphor.

21. The AC/DC lamp as set forth in claim 1 wherein said array of micro-LEDs emit white light by mixing red, blue and green light.

22. The AC/DC lamp as set forth in claim 1 wherein said array of micro-LEDs has a die size of less than approximately 1 millimeter by 1 millimeter.

23. An indicating lamp operable on a source of AC power, said lamp comprising:

a first serially-connected array of micro-LEDs grown on a substrate;

a second serially-connected array of micro-LEDs grown on said a substrate;

said first array being connected in parallel with said second array;

said second array being arranged such that it has a reversed current flow direction relative to said first array so that when said lamp is operated using said source of AC power illumination is sustained regardless of current cycle; and

said indicator lamp being fittable into a package formerly designed for use for a standard-sized LED.

24. An AC lamp comprising:

an integrated array of series connected micro-LEDs;

said micro-LEDs being multiple times smaller than a conventional 300 micron by 300 micron LED and thus causing said array to have a size which enables a substitution of said array in a conventional use of said conventional 300 micron by 300 micron LED; and

said array fitted into a standard-sized LED indicator lamp package.