Light valve imaging apparatus and method for providing gray scale

In electronic imaging apparatus of the type including (1) a linear light valve array which comprises a plurality of discretely addressable pixels activatable between light transmitting and non-transmitting conditions by selective application of an electrical field and a plurality of spaced linear electrodes adapted to apply electrical fields transversely across pixels of said array, (2) means for providing scanning movement between said array and a photosensitive image medium to facilitate successive line exposure periods of different portions of such image medium, (3) means for illuminating elements of said array with light and (4) addressing means for activating predetermined of said array pixels during each successive line exposure period in accordance with density information of respective lines of the image to be reproduced, the improvement wherein said addressing means includes (1) means for effecting each overall line exposure period activation of said array by enabling a plurality of distinct sub-period array activations, of substantially constant-magnitude potential throughout their respective durations, and (2) exclusive-or logic means for controlling energization of predetermined ones of said electrodes during such sub-period activations.

In the method of imaging wherein a light valve array, of the type including a plurality of discretely addressable pixel regions arranged in a line and adapted to selectively transmit or block light in response to respective electrical activations by spaced electrodes, is addressed in accordance with an electrical signal containing information for the respective pixel transmission of a line of the image to be reproduced, the improvement comprising addressing the pixel regions a plurality of times respectively during sub-periods of a given line transmission period and exclusive-or gating line information to said electrodes.