Automatic automobile rear view mirror assembly

Abstract

A variable reflectivity automobile mirror assembly is operable by automatic electrical circuitry responsive to variations of incident light upon the mirror and ambient light level about the automobile to provide positions of high and low reflectivity. The assembly also includes a support member or housing, a reflective mirror panel, motor means, actuation means secured to the housing and driven by the drive element of the motor, and a timed-drive circuit for directing the current through the motor in opposite directions to move the mirror between the two positions. the automatic circuitry can include photosensing means and means to combine the output of the photosensing means and to compare it to an independent source. The circuit can position the mirror in response to the output of the comparing means. The circuit can have means to automatically adjust the sensitivity of the circuit so that the incident light level needed to move the panel from the higher or lower reflectivity orientation decreases as ambient light level decreaases. This can be provided by the first and second photosensing means being part of an electrical bridge. Means are also provided to integrate the photosensing signals at different rates. A summer means can add the integrated signals. Means for preventing the mirror switching from a lower to a higher reflectivity position for a short time interval following switching to a lower reflectivity position is also provided. The present invention also includes circuitry for manual actuation of the mirror.