Abstract: A human-computer interface includes a plurality of transducers comprising of emitters ad transducers arranged to detect patterns relating to movement of an object such as a gesture or a user's hand within a detection volume in the vicinity of the transducers, and to provide an input to computer equipment depending on the pattern detected. The interface may perform a simple analysis of the date received by the transducer to detect basic gestures, or it may perform a more complex analysis to detect a greater range of gestures, or more complex gestures. The transducers are preferably infra-red or ultrasonic transducers, although others may be suitable. The transducers may be arranged in a linear, a two-dimensional, or a three-dimensional pattern. Signals emitted by emitters may be modulated to aid gesture identification. The computer equipment may be a standard computer, or may be a game machine, security device, domestic appliance, or any other suitable apparatus incorporating a computer.

Abstract: A ferroelectric liquid crystal device includes a layer of ferroelectric liquid crystal material contained between a pair of substrates, a first plurality of electrodes and a second plurality of electrodes defining a plurality of addressable liquid crystal pixels. A driving arrangement is provided for applying a first signal (Strobe) in succession to the first plurality of electrodes and for applying a plurality of second signals (Data) simultaneously to the second plurality of electrodes. The plurality of second signals are arranged to include non-rectangular wave signals which have a lower harmonic content than a rectangular wave. Non-uniform heating of the device as a result of the application of the second signals (Data) is reduced with consequent improvement in device performance.