Holographic light line sight

Abstract

A sight for determining the direction and distance from a viewer to a target employs a transparent panel containing a hologram of a line of light on a plain background. The line extends from one side of the field of view, near the viewer, away from the hologram, and terminates at its far end in the central portion of the field of view. A coherent light source illuminates the panel to reconstruct a three-dimensional virtual image of the line superimposed on the scene viewed through the hologram. By moving the panel and source relative to the viewer the line may be moved and by adjusting the angle of incidence of the reconstructing wavefront and the position of their source relative to the panel, the extension of the line from the viewer may be manipulated. In alternative embodiments a reticle or distance and direction indicia are formed along the line; a plurality of different lines are recorded on the hologram using reference beams bearing different angles to the recording plate so as to be selectively reconstructable; and the panel is associated with an artillery piece and the line is curved to approximate the trajectory of a projectile.