# US 5,707,139 A · Vertical cavity surface emitting laser arrays for illumination

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- Number: US 5,707,139 A
- Document ID: US5707139A
- Status: Granted
- Kind: A
- Application number: 08/548,346
- Filed: 1995-11-01
- Granted: 1998-01-13
- Earliest claimed: 1995-11-01
- Assignees: Hewlett-Packard Company
- Inventors: Roland H. Haitz
- Web page: https://patentgrep.com/patent/US5707139A

## CPC

- H01S 5/423: {having a vertical cavity}
- 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
- F21K 9/60: Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
- F21Y 2115/10: Light-emitting diodes [LED]
- F21Y 2115/30: Semiconductor lasers
- 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)}
- H01S 5/02208: characterised by the shape of the housings
- H01S 5/02253: using lenses
- H01S 5/02325: Mechanically integrated components on mount members or optical micro-benches
- Y10S 362/80: Light emitting diode
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- F21K: NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
- F21Y: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## 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

### Claim 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 2)

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

### Claim 4 (depends on 1)

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

### Claim 5 (depends on 2)

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.

### Claim 6 (depends on 5)

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

### Claim 7 (depends on 1)

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.