| 摘要 |
A direction controllable lighting unit 10 for use in a lighting system is described. The light emission of the lighting unit 10 may be directed into different directions, e. g. by use of a mechanically movable element 14, 60. At least two ultrasound transmitters 20a, 20b, or ultrasound receivers 21a, 21b are disposed at the lighting unit 10 such that they differ in position, or in direction or shape of the spatial intensity distribution or spatial distribution of reception sensitivity. A mobile control element 46 has at least one corresponding ultrasound transmitter or receiver 50. A difference between a signal from a transmitter received at multiple receivers, or a signal of multiple transmitters received at a single receiver is used to determine a relative direction of the direction controllable lighting unit 10 and the control element 46, and to control the direction of the lighting unit 10 in dependence thereof.
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