摘要 |
<p>An electro-optical arrangement includes an electrochromic device which can take either a cleared (transparent) state, a first display state or a second display state, and a driving stage which provides first and second electrode-drive signals to drive the first and second electrodes of the device. At least one of the electrode-drive signals is supplied by way of a polysilicon thin-film buffer. The driving stage in an initial clearing operation outputs approximately equal voltages to the electrodes, which places the device into its transparent state. Subsequently the driver stage applies voltages to the electrodes, such that the device assumes either the first display state or the second display state. In either state it is arranged for the device not to be subjected to more than a safe operating voltage. Preferably, in one of the electrochromic device's two display states one of its electrodes is supplied with a voltage which is higher than the voltage (Vcom) on the other electrode, while in the other of its two display states the one electrode is supplied with a voltage which is lower than the voltage (Vcom) on the other electrode.</p> |