Lighting device having a lighting unit

Patent metadata

Field	Value
Publication number	US-10132458-B2
Application number	US-201615736791-A
Country	US
Kind code	B2
Filing date	May 20, 2016
Priority date	Jun 17, 2015
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

A lighting device provides a lighting unit for emitting useful light and a sensor. The unit includes a laser diode for emitting pump radiation and a phosphor element, which during operation is irradiated by the laser diode and thereby excited and serves for converting the pump radiation into conversion light, which conversion light at least proportionally forms the useful light. The sensor monitors the pump radiation conversion and at the same time detects a conversion light intensity, and is arranged with respect to the phosphor element of the unit so that a portion of the useful light and a measurement portion of the conversion light is incident on the sensor. The lighting device operates so that the phosphor element at least at times is irradiated in a pulsed manner and thereby excited so that between two pulses the conversion light intensity detected by the sensor decreases by at least 10%.

First claim

The invention claimed is:

1. A lighting device comprising
a lighting unit for emitting useful light and a sensor,
wherein the lighting unit
comprises a laser diode for emitting pump radiation and a phosphor element, which during operation is irradiated by the laser diode and thereby excited and serves for converting the pump radiation into conversion light, which conversion light at least proportionally forms the useful light,

wherein the sensor is provided for monitoring the pump radiation conversion and at the same time is designed to detect a conversion light intensity, and is arranged with respect to the phosphor element of the lighting unit in such a way that a portion of the useful light and thus a measurement portion of the conversion light is incident on the sensor, and wherein the lighting device is configured for operation in such a way that the phosphor element at least at times is irradiated in a pulsed manner and thereby excited in such a way that between two pulses the conversion light intensity detected by the sensor decreases by at least 10%.

2. The lighting device as claimed in claim 1 , which is configured for operation in such a way that the pulsed excitation of the phosphor element is carried out in a first operating state and, in a second operating state, the phosphor element is irradiated and thereby excited in such a way that the conversion light intensity detected by the sensor falls by at most 5% relative to a maximum value attained during the second operating state, wherein the first and second operating states succeed one another alternately during the operation of the lighting device.

3. The lighting device as claimed in claim 2 , which is configured for operation in such a way that in each case when the lighting device is operated in the first operating state, the conversion light intensity detected by the sensor decreases by at least 10% at least five times.

4. The lighting device as claimed in claim 1 , wherein, for the pulsed irradiation of the phosphor element, the laser diode is operated with a pulsed output power.

5. The lighting device as claimed in claim 4 , which is configured for operation in such a way that the output power of the laser diode is reduced between the pulses by at least 30% relative to the output power during the respectively preceding pulse.

6. The lighting device as claimed in claim 1 further comprising a reflector comprising a reflection surface, via which the useful light is guided to a lighting application, wherein the reflection surface is provided with an interruption, through which that portion of the useful light which is incident on the sensor passes.

7. The lighting device as claimed in claim 1 , wherein a scattering means is assigned to the sensor, through which scattering means penetrates that part of the useful light which is then incident on the sensor.

8. The lighting device as claimed in claim 1 , wherein the useful light proportionally also contains non-converted pump radiation and a second sensor is designed to detect an intensity of a pump radiation incident thereon.

9. The lighting device as claimed in claim 1 further comprising a plurality of sensors for monitoring the conversion of the pump radiation, wherein a respective portion of the useful light is incident on each of the sensors.

10. The lighting device as claimed in claim 1 , further comprising a plurality of lighting units each designed for emitting useful light, wherein in each case a portion of the useful light emitted by a respective one of the lighting units is incident on the sensor.

11. The lighting device as claimed in claim 1 , which is configured at least to reduce a propagation of the pump radiation in a fault situation.

12. The lighting device as claimed in claim 11 , which is configured to ascertain the fault situation depending on a decrease in the conversion light intensity detected by the sensor.

13. The lighting device as claimed in claim 12 , further comprising a plurality of lighting units each designed for emitting useful light, wherein in each case a portion of the useful light emitted by a respective one of the lighting units is incident on the sensor, wherein the lighting device is configured to individually specify in the fault situation which of the lighting units is affected.

Assignees

• Osram Gmbh

Inventors

• Haas Norbert
• Hadrath Stefan

Classifications

• H01S5/06835 Primary

  Stabilising during pulse modulation or generation · CPC title

• F21Y2115/20

  Electroluminescent [EL] light sources · CPC title

• F21S41/37

  characterised by their material, surface treatment or coatings · CPC title

• B60Q11/005

  for lighting devices, e.g. indicating if lamps are burning or not · CPC title

• H01S5/005

  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 title