A device for producing images of a plurality of speechinformation symbols associated with speech sounds produced by aspeaker into the field of view of a hearing-impaired person withone or more light emitting or illuminated arrays mounted paraxiallywith the viewer's line of sight on a transparent plate whichsubtends and mounts an adjacent eyeglass lens. A mirror is mountedon the lens to produce a magnified image in the field of view andreflect the image back to the viewer. The interior surface of thelens may be coated to form the mirror or spherical dimples may beground into the surface before coating and the coated dimples thenfilled with a material having substantially the same refractiveindex as the lens.
Method and apparatus for displaying speech information
McCartney, M. (1983). IPC No. U.S. Method and apparatus for displaying speech information. (U.S. Patent No. 4414431).