Bistable deflection system

An imaging device, comprising:

• a. a photosensitive imaging member capable of forming a latent image in response to light of wavelength .lambda. and a source of light comprising light of wavelength .lambda.;
• b. between said photosensitive imaging member and said source of light, a bistable deflector comprising, between two transparent electrodes, an about 1 micron to about 6 micron thick layer of homogeneously aligned nematic liquid crystalline material having negative dielectric anisotropy;
• c. voltage means for applying a d.c. voltage between said two electrodes at least at the parallel variable diffraction mode voltage threshold for said nematic liquid crystalline material wherein vortical domains of said liquid crystalline material are formed in a direction parallel to the direction of initial homogeneous alignment, said domains being substantially parallel one to the other and having a spatial frequency dependent upon the magnitude of said d.c. voltage, said voltage means in response to an electrical pulse increasing the voltage level to at least the critical angle voltage for said light of wavelength .lambda. wherein said spatial frequency is sufficient to totally internally reflect said light of wavelength .lambda. within said layer of liquid crystalline material, and in the absence of an electrical pulse decreasing the voltage level to below said critical angle voltage wherein said spatial frequency is insufficient to totally internally reflect said light of wavelength .lambda. within said layer of liquid crystalline material but is sufficient to diffract said light of wavelength .lambda. through said layer of liquid crystalline material and said electrodes;
• and
• d. scanning means for directing, at predetermined positions upon said photosensitive member, light of wavelength .lambda. passing through said bistable deflector.