Eye-safe laser-based lighting

Abstract

The invention relates to a laser-based light source comprising a laser device (1) adapted for generating laser light of a predetermined laser wavelength and emitting this laser light as a laser beam; a light-conversion device (2) for converting at least part of the laser light into converted light; a laser-output sensor (7) for determining a laser-output signal proportional to the output of laser light emitted by the laser device (1); a converted-light sensor (6) for determining a converted-light signal proportional to the output of converted light emitted by the light-conversion device (7); and a controller (9) which is adapted for receiving the laser-output signal and the converted-light signal, for determining a safe-to-operate parameter, based on the laser-output signal and the converted-light signal, and for controlling the operation of the laser-based light source, based on a comparison of the safe-to-operate parameter with a at least one predefined threshold. In this way, a laser-based light source is proposed which enables reliable eye-safety in an easy way.

Description

FIELD OF THE INVENTION[0001]The invention relates to the field of a laser-based light source and a method of operating the same, and especially to eye-safe laser-based lighting.BACKGROUND OF THE INVENTION[0002]During the last decades, thanks to the advances of semiconductor technology, LEDs (Light Emitting Diodes) have become more and more important in lighting applications. Technological breakthroughs in high-power LEDs have opened the door to new lighting concepts driven by miniaturization, lifetime, efficiency and sustainability.[0003]Compared to LEDs, the advantage of lasers is their much higher brightness. Semiconductor lasers have started to become available in output powers of several Watts, thus enabling a high lumen output. Laser light by itself will not be of much use for illumination since the laser beam is too bright to be eye-safe, too monochromatic for faithful colour reproduction and will result in annoying speckle due to its coherence. A convenient way to resolve the...

AI Technical Summary

Benefits of technology

The invention is a laser-based light source that is safe to operate and easy to adjust. It includes a laser device that generates laser light, a light-conversion device that converts at least part of the laser light into converted light, a laser-output sensor that determines a laser-output signal correlated with the laser light, a converted-light sensor that determines a converted-light signal correlated with the converted light, and a controller that receives the laser-output and converted-light signals and adjusts the operation of the light source based on these signals. The invention is applicable to different types of light-conversion devices, such as phosphors or scattering devices, and can be used in various situations, such as opening the light source or detecting damage to the optical components. The invention ensures reliable eye-safe operation and prevents external straylight from entering the light source.

Problems solved by technology

Laser light by itself will not be of much use for illumination since the laser beam is too bright to be eye-safe, too monochromatic for faithful colour reproduction and will result in annoying speckle due to its coherence.

However, one critical issue with laser-based lighting is the fact that the light source should adhere to strict legislation and be eye-safe under all circumstances, even when tampered with.

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