Patent Number: 6,305,807

Title: Digital electrochromic mirror system

Abstract: An electrochromic rearview mirror system for a vehicle includes anelectrochromic reflective element having an electrochromic cell, whereinthe reflective element colors to a partial reflectance level in responseto a drive signal applied to the cell. The rearview mirror assemblyadditionally includes a drive circuit which applies a pulsed drive signalto the electrochromic cell in order to establish the partial reflectancelevel of the reflective element. The drive circuit controls the partialreflectance level as a function of the duty cycle of the pulsed drivesignal, which has a pulse repetition rate of at least approximately 10cycles per second and preferably at least approximately 20 cycles persecond. The drive circuit additionally adjusts the amplitude of the pulsesas a function of the voltage developed across the electrochromic cell.

Inventors: Schierbeek; Kenneth L. (Zeeland, MI)

Assignee:

International Classification:

Expiration Date: 10/23/2013