Light deflector comprising cascaded light displacement means and hologram plate

Claim 1

A light deflector for deflecting an incident coherent light beam into a desired direction comprising a hologram plate, said plate having recorded therein interference fringes between a narrow coherent light beam deflected in various directions from a fixed position and a wide coherent light beam in a fixed direction, said slate diffracting a coherent light beam incident on said hologram plate at each position on an incident plane in said fixed direction to emit a deflected light beam in a direction passing through a fixed point spaced from said hologram plate, and light displacement means disposed in front of said recording hologram plate for displacing a coherent light beam projected thereon at an incident position in said fixed direction without changing its direction so as to displace only its optical path in parallel to project said coherent light beam onto said hologram plate at a desired position thereon, whereby said coherent light beam may be deflected in a desired direction passing through said fixed point after passing through said hologram.