04177354 is referenced by 48 patents and cites 7 patents.

A light-spot-emitting stylus (21) is utilized by an operator to write graphical information on the surface of a simple multilayer planar transducer device (10) that includes a photoconductive layer (16) sandwiched between a transparent conductive layer (14) and a resistive layer (18) that includes spaced-apart electrodes (23 through 32 . . . ). In response to the writing spot, the transducer device generates electrical output signals indicative of successive coordinate positions of the spot on the transducer surface. In turn, these signals are transmitted to a remote location where the originally written graphical information is reconstructed. Moreover, by positioning the transducer on the face of a display unit (51), the information being written on the transducer can be viewed by the operator during the writing process.

Title
Graphic communications apparatus
Application Number
5/896705
Publication Number
4177354
Application Date
April 17, 1978
Publication Date
December 4, 1979
Inventor
Max V Mathews
New Providence
NJ, US
Agent
Lucian C Canepa
Assignee
Bell Telephone Laboratories Incorporated
NJ, US
IPC
G08C 21/00
View Original Source