Patent ID: 7550930

Claim:
A lighting device for an electronic or electromechanical apparatus, the lighting device including: (a) a display device for displaying time-related data or data not related to time; (b) a light source, operable in a first mode to produce lighting and operable in a second mode to detect ambient luminosity, arranged to light the display device and to measure intensity of ambient light; and (c) a measurement stage comprising the light source provides an electric signal representative of ambient lighting conditions measured by the light source, wherein an RC circuit comprising a capacitor and a resistor connected in series is operably connected to the measurement stage, said RC circuit supplying a first signal when the lighting device is in a brightly lit environment and maintaining the supply of this first signal even when the lighting device is passed to an environment in semi-darkness or darkness until a predetermined time corresponding to the time necessary for the human eye to become accustomed to the semi-darkness or darkness has been reached, the RC circuit supplying a second signal different from the first signal after the moment when the human eye has become accustomed to the semi-darkness has been reached.