Vertical cavity surface emitting laser arrays for illumination

• US 5,758,951 A
• Filed: 06/27/1997
• Issued: 06/02/1998
• Est. Priority Date: 11/01/1995
• Status: Expired due to Fees

• Current Assignee: Avago Technologies Fiber IP Singapore PTE Limited (Broadcom, Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Haitz, Roland H.
• Primary Examiner(s): Husar, Stephen F.
• Application Number:
  US08/884,378
• Time in Patent Office: 340 Days
• Field of Search: 362/230, 362/231, 362/240, 362/242, 362/244, 362/259, 362/268, 362/800, 372/43, 372/45, 372/46, 372/50
• US Class Current: 362/259
• 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 illumination source comprising:

a plurality of vertical cavity surface emitting laser chips, each chip having a plurality of vertical cavity surface emitting laser elements, the elements on each chip generating laser light of a predetermined wavelength and being coupled together so that they can be driven at least in parallel, the vertical cavity surface emitting laser elements being at least 20 μ

m in diameter, each element having multiple lasing filaments, the filaments lasing independently of one another, without temporal coherence;

a power supply coupled to each of the chips, the power supply being at least capable of supplying drive current to all the elements in all of the chips in parallel; and

a controller coupled to the power supply for controlling the light output of the chips.

2. The illumination source of claim 1 wherein the elements comprising each chip generate light of the same wavelength, the wavelength of light generated by each chip differing from that of every other chip.

3. The illumination source of claim 1 wherein the chips can simultaneously be modulated to transmit information and generate illumination.

4. The illumination source of claim 1 wherein a phase destroying optical system is placed between the illumination source and objects being illuminated, the phase destroying optical system reducing the temporal coherence of the individual lasing elements.

5. The illumination source of claim 1 wherein the power supply can be regulated by the controller to provide a variable drive current to each of the lasing elements simultaneously, thereby permitting the illumination source to be dimmed.

6. The illumination source of claim 5 wherein the illumination source can further be dimmed by forming a single cathode contact to all elements on a chip and forming a plurality of anode contact groups, each element being coupled to one anode contact group, there being at least two anode contact groups on each chip, the dimming being accomplished by selectively deactivating at least one of the anode groups.

7. An illumination source comprising:

a plurality of vertical cavity surface emitting laser chips, each chip having a plurality of vertical cavity surface emitting laser elements, the elements on each chip generating laser light of a predetermined wavelength and being coupled together so that they can be driven at least in parallel, the vertical cavity surface emitting laser elements being separated form one another by a distance of between 20 μ

m and 50 μ

m;

a power supply coupled to each of the chips, the power supply being at least capable of supplying drive current to all the elements in all of the chips in parallel; and

a controller coupled to the power supply for controlling the light output of the chips.

8. The illumination source of claim 7 wherein the elements comprising each chip generate light of the same wavelength, the wavelength of light generated by each chip differing from that of every other chip.

9. The illumination source of claim 7 wherein the chips can simultaneously be modulated to transmit information and generate illumination.

10. The illumination source of claim 7 wherein a phase destroying optical system is placed between the illumination source and objects being illuminated, the phase destroying optical system reducing the temporal coherence of the individual lasing elements.

11. The illumination source of claim 10 wherein the power supply can be regulated by the controller to provide a variable drive current to each of the lasing elements simultaneously, thereby permitting the illumination source to be dimmed.

12. The illumination source of claim 11 wherein the illumination source can further be dimmed by forming a single cathode contact to all elements on a chip and forming a plurality of anode contact groups, each element being coupled to one anode contact group, there being at least two anode contact groups on each chip, the dimming being accomplished by selectively deactivating at least one of the anode groups.