Image display apparatus

Claim 1

An image display apparatus comprising a laser cavity having an axis of symmetry and including an active laser medium for stimulated emission of light within said cavity and a first and second nontransmissive mirror respectively arranged perpendicular to said axis of symmetry at the ends of the cavity, said cavity and axis of symmetry being angular and said cavity further including a third mirror located at the apex of the angle of said axis of symmetry for reflecting said light between said first and second mirrors said third mirror having an aperture therein, A phase-modulating electro-optic crystal located within said cavity between said first and second mirrors in the path of said light and having its surface perpendicular to said axis of symmetry, means external to said cavity for varying the index of refraction of said crystal for phase modulating said light, said means including an electron gun positioned for scanning said crystal with a beam of electrons projected through said aperture normally to the surface of said crystal for varying the index of refraction of said crystal in spatially oriented incremental areas in accordance with the spatial distribution of intensity of any image to be coupled out of said cavity, wherein said varying of said index of refraction modulates said light into a zero order light beam and higher side order light beams, said first nontransmissive mirror being located in the path of said zero order light beam for reflecting said zero order beam back into said cavity and allowing said side order beams to pass out of said cavity.