| 摘要 |
<p>The present invention relates to a lighting system comprising a plurality of light emitting diodes. In order to obtain a sensor signal, at least one of the diodes (3) is switched between two states (MODE 1, M0DE2). In a first state (MODE 1) the diode emits light and in a second state (MODE 2) the diode is switched off and use is made of the fact that the PN junction of the diode generates a small current which depends on the light incident thereon. This current is measured in order to provide the sensor signal.</p> |
