Vertical cavity surface emitting laser arrays for illumination

• US 5,707,139 A
• Filed: 11/01/1995
• Issued: 01/13/1998
• Est. Priority Date: 11/01/1995
• Status: Expired due to Term

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Haitz, Roland H.
• Primary Examiner(s): Husar, Stephen F.
• Application Number:
  US08/548,346
• Time in Patent Office: 804 Days
• Field of Search: 362/230, 362/231, 362/240, 362/242, 362/244, 362/259, 362/800, 362/268, 372/43, 372/50, 257/88, 257/90, 257/96
• US Class Current: 362/231
• 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 9/60 Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: F21Y 2115/30 Semiconductor lasers
• CPC Class Codes: H01S 5/005 Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping H01S5/026, H01S5/18388 take precedence
• CPC Class Codes: H01S 5/02208 characterised by the shape of the housings
• CPC Class Codes: H01S 5/02253 using lenses
• CPC Class Codes: H01S 5/02325 Mechanically integrated components on mount members or optical micro-benches
• CPC Class Codes: H01S 5/423 having a vertical cavity
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

Arrays of vertical cavity surface emitting lasers ("VCSEL"s) used for illumination in both infra-red and visible light wavelengths are described. By using several different arrays, each array generating light of a different wavelength, a replacement for conventional lighting sources can be obtained. The present invention offers lower power consumption and longer operating lifetime than known lighting technologies.

Claims

1. An infra-red illumination source comprising:

a plurality of vertical cavity surface emitting laser chips, each chip comprised of a plurality of vertical cavity surface emitting laser elements, the elements on each chip emitting infra-red light and being coupled together so that they can be driven at least in parallel, the chips being coupled together by a combination of series and parallel couplings; and

a power supply coupled to the chips for providing drive current to the elements.

2. The source of claim 1 wherein the elements on each chip generate infra-red light of a different wavelength than that generated by the elements on the other chips.

3. The source of claim 2 wherein the elements on each chip generate infra-red light with a wavelength between 700 and 1000 nm.

4. The source of claim 1 wherein the elements can be modulated at a frequency of at least 10 MHz.

5. The source of claim 2 wherein a phase destroying optical system is placed between the chips and objects being illuminated, the phase destroying optical system reducing the temporal coherence of the elements.

6. The source of claim 5 wherein the source is used to provide infra-red illumination for security purposes.

7. The source of claim 1 wherein each element has a cathode and an anode contact, the cathode contact of all elements on a chip being common and the anode contacts being formed into at least two separate anode groups, dimming of the source then being accomplished by a combination of decreasing the drive current to the elements and turning off those elements coupled to at least one of the anode groups.