| 摘要 |
The rear mirror has a foot for fitting to the vehicle, and a mirror glass. The microphone is built into it, pref. at its outer free end so as to prevent as far as possible the pick-up of disturbing sound reflexes from the vehicle bodywork. Sound is picked up by the microphone only from a limited area in a well defined direction, the area being where another vehicle on approaching from the rear is in an oblique position in relation to the microphone. Such sound is of a frequency significant and common to vehicles circulating in every day traffic. The mirror incorporates a lamp fitted behind a red, transparent plastic plate bearing the text WARNING, located on the side of the mirror facing the rear of the vehicle, i.e. between the mirror glass and the vehicle and a near as possible to the driver to facilitate observation. A battery with associated current circuit connects the microphone to the lamp, so that the circuit incorporating the lamp is connected when the microphone is activated by sound from a vehicle approaching from the rear, causing the lamp to illuminate. |
