Patent Application
20110304268
The invention relates to a lighting device including at least one semiconductor light source and a method for operating a lighting device including at least one semiconductor light source.
Retrofit lamps with semiconductor light sources are known. A semiconductor retrofit lamp is provided to replace conventional lamps, such as incandescent lamps and halogen lamps. To this end, a semiconductor retrofit lamp includes a conventional base and, advantageously, its external contour does not substantially exceed the dimensions of the conventional lamp to be replaced. Nowadays, typical LED lamps, and also LED retrofit lamps, include light-emitting diodes (LEDs) and a lens (e.g. a translucent—opaque or transparent—cover such as a bulb or a cover disk and/or an optical component such as a reflector or a lens), a heat sink or a carrier, control electronics and a base.
The object of the present invention is to provide a possibility for a more versatile use of a lighting device.
This object is achieved by means of a lighting device and a method according to the respective independent claim. Preferred embodiments can be derived in particular from the dependent claims.
The lighting device is equipped with at least one semiconductor light source, wherein the lighting device includes at least one sensor and a logic circuit functionally connected to the at least one sensor, which is arranged to trigger at least one action of the lamp upon at least one predetermined sensor signal of the at least one sensor. In the following, this logic circuit will be referred to simply as the “evaluation electronics”.
The sensor enables the lighting device automatically to recognize changing ambient and/or operating parameters and, by means of suitably arranged evaluation electronics, to react flexibly thereto. This in turn enables the lighting device to be used more diversely, e.g. for the performance of functions other than normal lighting and/or for use in demanding environments. This is because the lighting device now includes an “intelligence” and can in particular perceive and further process internal physical parameters and ambient parameters.
The lighting device can be embodied as a light or as a general light fixture (“fixture”)—e.g. as a unit with a lamp. The lighting device can also be embodied as a lamp: this has the advantage that the new, sensor-assisted functions can be implemented at the user side without any functional modification to the light operating the lamp.
The lamp can be a retrofit lamp. This enables the implementation of the new sensor-assisted functions at the user side by simply replacing the lamp and without any modification to the light.
The at least one sensor can, for example, include a moisture sensor, a smoke sensor, a temperature sensor, an acoustic sensor, a motion sensor, a brightness sensor, a pressure sensor, an acceleration sensor, a color sensor and/or a position sensor.
The lighting device can in particular include at least one moisture sensor, wherein the evaluation electronics can be arranged to activate or amplify a heat source of the lighting device when a sensor signal of the at least one moisture sensor reaches or exceeds a predetermined moisture threshold. The lighting device can include a dedicated heating element, in particular a resistance heating element and/or an IR LED, as a heat source.
For example, the moisture sensor can be used to protect the lighting device, and in particular the light source, against the penetration of moisture. The light source(s) can absorb moisture through a casting compound (e.g. made of silicone) or through possible gaps between their connection legs and the housing of the light source(s). In the worst case, the moisture can damage the light source(s) and result in the failure of the light source(s). This type of damage can in particular occur when the light source(s) are exposed to moisture for a lengthy period and are not operated or only operated at a very low current so that moisture is not baked out of the housing. An operation of this kind is conceivable, for example, in emergency lighting located in a moist environment and which is not normally in operation. In an emergency, however, the light is required to function when a safety-relevant part is involved. Especially for use in moist environments, lighting devices, e.g. lights or lamps, can be mounted in a dust-proof and moisture-proof housing in order to prevent the moisture damaging the electronics and/or the light source(s). This protection by the housing is described by so-called “IP degrees of protection”. However, even housings with this highest IP degree of protection are not able completely to prevent the penetration of moisture.
The moisture sensor is used to sense a moisture value or a measured value correlated therewith (e.g. resistance value) in the interior of the lighting device and relay it to the evaluation electronics. The evaluation electronics can identify from the moisture value determined whether the moisture in the interior is too high and consequently could cause damage. The evaluation electronics can then trigger an action to reduce the moisture in the lighting device to a non-critical level. To this end, the evaluation electronics can, for example, activate or amplify a heat source in the interior of the lighting device so that the interior of the lighting device is baked.
The type of heat source is not restricted and can, for example, be the light source(s) whose heat loss during light generation is used for the baking. For the baking, the at least one light source is then either switched on or ramped up from a lower luminous intensity to a higher luminous intensity. The heat source can also include at least one resistance heating, which is supplied with a defined current. The heat source can also include a dedicated infrared radiator, e.g. an infrared light-emitting diode (IR LED).
The moisture sensor can advantageously be positioned as closely as possible to the light source and measures the moisture at the light source with a high degree of accuracy. The moisture sensor can, for example, be a simple capacitive sensor (e.g. a sensor from the series HCH-1000 made by the company Honeywell) or even a sensor offering an additional function, such as a temperature measurement, e.g. a sensor from the SHTx series made by the company Sensirion.
Recognition whether the moisture in the interior of the lighting device is too high can advantageously be achieved by comparison with one or more predetermined moisture thresholds. If, for example, in one possible embodiment a predetermined moisture threshold of 60% relative humidity (RH) is reached or exceeded, the evaluation electronics activate the heat source of the lighting device and hence bake the moisture out of the lighting device. When the level drops below the moisture threshold, the heat source is deactivated again. In a further possible embodiment, the heat source is activated when a prespecified first moisture value is exceeded, e.g. 60% RH, and the moisture baked out of the housing. The heat source is only deactivated again when the level drops below a predefined second moisture value, which is lower than the first moisture value, e.g. 50% RH. This involves the traversal of a “moisture hysteresis loop”, which prevents the at least one heat source for baking out the moisture from being switched on and then back off again at short intervals.
The use of the moisture sensor has the advantages that (a) the housing can be less complicated to construct since a lower IP degree of protection can be selected, (b) the reliability of the lighting device can be increased due to the fact that moisture-induced damage, in particular to the light source and the electronics, can be minimized and (c), particularly in the case of safety-relevant lighting devices (e.g. for emergency lighting in a tunnel etc.), creeping damage due to moisture can be avoided.
The use of a smoke sensor enables the lighting device to be simultaneously used as a smoke detector. The lighting device can, for example, emit an alarm signal on the detection of a predetermined amount of smoke. The alarm signal can be an optical signal, e.g. flashing and/or a color change of the light emitted by the lighting device, e.g. a color change from white to red. The lighting device can additionally include an acoustic signal transmitter (loudspeaker, siren, horn etc.), which, in the case of an alarm, emits an acoustic signal as an alarm signal additionally or alternatively to the optical signal. It is also possible to use the transmission (e.g. effected wirelessly or via the modulation of the mains voltage) of an alarm signal to a central monitoring unit, which then relays or triggers an alarm.
The use of a temperature sensor enables an outside temperature and/or a temperature in the housing of the lighting device to be monitored. If temperatures are achieved at which reliable operation of the lighting device is no longer guaranteed (overheating), the power to the lighting device can be throttled or the lighting device can be switched off completely. Alternatively or additionally, it is also possible for an (e.g. optical or acoustic) alarm signal to be emitted.
The use of an acoustic sensor in the lighting device enables the lighting device to be controlled by noise, for example. For example, the lighting device can be switched on by a single first clapping of the hands and switched off by a further clapping of the hands.
The use of a motion sensor in the lighting device enables the lighting device to be simultaneously used as a motion detector. As soon as, for example, someone approaches the lighting device, it comes on and/or emits an acoustic signal. This enables a separate motion detector to be spared.
A brightness sensor can be used to measure the brightness of the ambient light. If, for example, in one possible embodiment, the level drops below a first brightness threshold for the ambient light, the lighting device is switched on, if a second brightness threshold is exceeded, the lighting device then switches off again. The first brightness threshold can be equal to the second brightness threshold, alternatively the second brightness threshold can be higher than the first brightness threshold in order to a prevent the constant switching-on and switching-off of the lighting device. It is also possible to provide a twilight setting so that, as the ambient light decreases, the dim level of the lighting device is increased.
If a pressure sensor, in particular an air pressure sensor, is used, this sensor can respond, for example in the case of a pressure drop, e.g. in an airplane or in a hyperbaric chamber, and switch on the light source(s) to provide emergency lighting and/or emit an acoustic signal.
An acceleration sensor can be used to trigger the evaluation electronics if an acceleration threshold sensed by the acceleration sensor is exceeded, for example in the case of an earthquake, and initiate the switching-on of the light source(s), optionally also by means of an integrated battery-powered emergency power supply.
The use of a position sensor can, for example, prevent location-induced overheating of the lighting device. For example, LED-lighting devices dissipate the heat formed during light generation via a heat sink. The cooling efficiency of heat sinks, which are generally based on the free convection of air, is frequently determined by their mounting position. For example, horizontal installation of the flow channel generally impairs the efficiency of the heat sink. This mounting position can be determined from the position sensor so that, in the case of a non-optimum position, the evaluation electronics can reduce the power of the lighting device in order to avoid overheating.
The color sensor can be used to detect a change to the beam color due to a temperature and optionally, with a color-tunable light source, correct it by a color change of the light emitted by the lighting device. It is also possible to adjust the luminosity, in order to limit the change to the beam color.
To this end, and also generally for the processing of sensor values and/or control of the semiconductor light source(s), the lighting device can advantageously be equipped with a suitable control circuit. Additionally or alternatively, the lighting device can include—wireless or wire-bound—data transmission means for the transmission of measured values and/or reception of control signals. The control circuit can advantageously also be used to perform a function test. Alternatively, the lighting device can include a dedicated function test unit for the performance of a function test.
In response to a predetermined sensor signal of the at least one sensor, the lighting device can generally inter alia initiate
The at least one sensor can, for example, be arranged with the at least one semiconductor light source on a common substrate (e.g. a printed circuit board); arranged on a lens of the lighting device, thus enabling direct coupling to the incident ambient light; on a heat sink of the lighting device, thus enabling a reliable direct temperature measurement, e.g. taking into account (safety) thresholds for exposed surfaces and/or arranged on a base of the lighting device. Generally, the sensor can be arranged on an outer side of the lighting device or within the lighting device. For example, the sensor can be integrated in the lens, e.g. in a primary lens, secondary lens and/or a cover. The sensor can also be seated in the housing directly on a printed circuit board provided for mounting the light source(s), on a driver board or—for particularly simply mounting—on a separate printed circuit board.
The at least one sensor can be present as a combined sensor/(evaluation) electronics element. For example, the sensor can be integrated in the evaluation electronics. This enables a separate component to be dispensed with, thus saving costs and space.
The at least one semiconductor light source can include at least one diode laser, advantageously however at least one light-emitting diode. The light-emitting diode can emit monochromatic or polychromatic light, e.g. white light. In the case of a plurality of light-emitting diodes, these can emit, for example, isochromatic (monochromatic or polychromatic) and/or heterochromatic light. For example, an LED module can comprise a plurality of LED chips (‘LED cluster’), which together can issue a white mixed light, e.g. in ‘cold white’ or ‘warm white’. To generate a white mixed light, the LED cluster preferably includes LED chips, which emit light in the primary colors red (R), green (G) and blue (B). Hereby, individual or a plurality of colors can also be generated simultaneously by a plurality of LEDs; for example, combinations RGB, RRGB, RGGB, RGBB, RGGBB etc. are possible. However, the color combination is not restricted to R, G and B. To generate a warm-white shade, it is also possible, for example, for one or more amber-colored LEDs (A) to be present. In the case of LEDs with different colors, these can also be controlled in such a way that the LED module emits in a tunable RGB-color range. To generate a white light from a mixture of blue light with yellow light, it is also possible to use LED chips provided with luminescent material, e.g. in surface mounting technology, e.g. in so-called chip-level conversion technology. It is also possible to use methods, such as red/green combination by means of conversion technology. Obviously, “conventional” volume conversion is also possible. An LED module can also include a plurality of white individual chips enabling simple scalability of the luminous flux to be achieved. The individual LEDs and/or the modules can be equipped with suitable lenses for beam guidance, e.g. Fresnel lenses, collimators, etc. Instead of or in addition to inorganic light-emitting diodes, e.g. based on InGaN or AlInGaP, generally also organic LEDs (OLEDs) can also be used.
The lighting device can advantageously include a current-storage device, e.g. a battery or an accumulator so that in particular safety-relevant functions (fire detection by means of smoke detection, earthquake detection by acceleration detection etc.) continue to function even in the event of an interruption to the power supply.
The method is used to operate a lamp with at least one semiconductor light source and at least one sensor, wherein at least one action of the lamp is triggered upon at least one predetermined sensor signal of the at least one sensor.
The following figures describe the invention schematically in more detail with reference to exemplary embodiments. Hereby, for the sake of clarity, the same elements or elements with the same function are given the same reference numbers.
Alternatively to the embodiment of the sensor 6 as a moisture sensor, it can also be embodied as a smoke sensor, a temperature sensor, an acoustic sensor, a motion sensor, a brightness sensor, a pressure sensor, an acceleration sensor or a position sensor. The sensor 6 can also be attached to an outer side of the lamp 1.
However, the sensor can also be attached on the carrier 3 of an LED retrofit lamp 11, as shown in
Obviously, the present invention is not restricted to the exemplary embodiments shown. For example, it is also possible for two or more sensors of the same or different types to be arranged on the lighting device. It is also possible for the lighting device to contain a control circuit, e.g. in the form of an integrated circuit. It is also possible for a—integrated or dedicated—function test unit to be present for the performance of a function test. The lighting device can also include a current-storage device.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2009 010 180.2 | Feb 2009 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP10/51312 | 2/3/2010 | WO | 00 | 8/22/2011 |
