Linear Total Internal Reflection Spatial Light Modulator For Laser Printing

This paper describes an alternative technique to laser scanning for nonimpact printing on a photosensitive medium. The laser light is formed into a line of illumination which illuminates a linear array of light modulators which in turn is imaged onto the photoreceptor. This array is implemented as a total internal reflection (TIR) spatial light modulator, with the electrodes and drive electronics fabricated on an integrated drive element which is placed against the total reflection surface of an electro-optic crystal. The localized change in index of refraction produced by the fringing field between each two electrodes is read out with Schlieren readout optics which image the TIR interface onto the photoreceptor. This paper will describe the basic device concept, present measurements on the required electrode spacing, length, and drive voltage, discuss analytically and experimentally the cacteristics of the relay imaging system, and show experimental results for modulators built with simple test electrode structures and a passively addressed full scale silicon device.