Pixel intensity control in electro-optic modulators

摘要

A laser imager comprises a modulator with an array of electrodes to control picture elements individually or by groups to produce images on a recording plane. The light intensity of each picture element or group of elements is determined by electrical potential applied between sets of controlling electrodes. These levels can be manually set or automatically exercised during a balancing routine through a feed-back loop using a photodetector to monitor and detect elements producing a light intensity higher than a set value. Control means assign to these elements a "correction voltage" to lower the density of elements they control. These correction values obtained after one or repeated balancing routines are stored in a memory and are used during the imaging cycle to produce images of substantially equal intensity on the recording medium. Different electrode arrangements to control the intensity of picture elements can be applied to different kinds of modulators and for different power levels of radiated energy.