Three-dimensional Display

Abstract

A three-dimensional display is disclosed which uses a variable focal length lens through which two-dimensional images of an object are viewed. In one embodiment, a sequence of different images representative of cross sections of the object along its depth dimension are presented by a two-dimensional display apparatus such as a high resolution CRT. The viewer sees these two-dimensional images of the object through the variable focal length lens. The focal length of the lens is changed in synchronization with the two-dimensional images such that each cross section image is seen at a different focal length, thus resulting in a three-dimensional image of the object. The rate of change of the two-dimensional images and the focal length of the lens is higher than the retention rate of the eye of the viewer, thus the images presented appear to fuse into a coherent three-dimensional image. Also disclosed is a ?uid-?lled lens having an optically transparent elastic membrane for one optical surface which changes the lens focal length by changing membrane curvature in response to ?uid pressure changes. A controller is used to control the sequence of two-dimensional images presented and the fluid pressure of the lens. The controller may also size particular two-dimensional images of the object to produce a proper perspective in the three-dimensional image.