Acoustic-wave device

Claim 1

An acoustic-wave device comprising: a light modifying member having three dimensions, said member including layers of electret material and an electrooptic material associated with each layer of the electret material, said member being responsive to a combination of three mutually crossing acoustic waves and a non-acoustic energy condition, said energy condition being applied momentarily at preselected times when said acoustic waves are at preselected intersection points in the member, such that a changed, electrically polarized condition is produced at said intersection points in the electrooptic material, means applying the acoustic waves to the member in three, mutually perpendicular directions, means momentarily applying the non-acoustic energy condition to the member at said preselected times, wherein the changed, electrically polarized condition includes a spatial change in light impinging on said member producing a three-dimensional image and wherein said spatial change is not affected by subsequent applications of said non-acoustic energy condition, and wherein the changed, electrically polarized condition produced at each preselected point during the momentarily applied non-acoustic energy condition is a change in birefringence.