Abstract: A head-coupled display device for use in presenting electronically generated visual images to a viewer. The device includes a headpiece worn by a viewer, and an image display screen mounted in the headpiece for presenting electronically generated images. A fresnel lens is positioned adjacent the screen for focusing images from the screen at a selected position for viewing as a virtual image. The lens has a set of concentric converging rings whose surface curvatures act to minimize rectilinear distortion of the virtual images perceived by the viewer over the entire field of view of the image.

Abstract: In one embodiment of the invention, a plurality of sensors are placed over the joints of a hand. Each motion sensor comprises an optical fiber disposed between a light source and a light sensor. An upper portion of the fiber is treated so that transmission loss of light being communicated through the optical fiber is increased only when the fiber bends in one direction. In another embodiment of the invention, a flexible tube is disposed in close proximity to a finger joint and bends in response to bending of the finger. A light source and light sensor are provided on opposite ends of the tube for continuously indicating the extent of bending of the tube. A wedge is disposed between the tube and the finger for setting the tube straight when the finger is hyperextended for eliminating the symmetry of the output signal which ordinarily would result from bending of the tube on opposite sides of the axis of movement.

Abstract: An optical flex sensor is provided and consists of a flexible tube having two ends, a reflective interior wall within the flexible tube and a light source placed within one end of the flexible tube and a photosensitive detector placed within the other end of the flexible tube to detect a combination of direct light rays and reflected rays when the flexible tube is bent.