Free stylus position locating system

• US 3,342,935 A
• Filed: 01/20/1964
• Issued: 09/19/1967
• Est. Priority Date: 01/20/1964
• Status: Expired due to Term

• Current Assignee: Charles Leifer Joseph, Julius Sobol Erwin, Mittelman J.R. Louis
• Original Assignee: Charles Leifer Joseph, Julius Sobol Erwin, Mittelman J.R. Louis
• Inventors: CHARLES LEIFER JOSEPH, MITTELMAN JR LOUIS, JULIUS SOBOL ERWIN
• Application Number:
  US04/338,883
• Time in Patent Office: 1,338 Days
• US Class Current: 178/19.03
• CPC Class Codes: G06F 3/0442 using active external devices, e.g. active pens, for transmitting changes in electrical potential to be received by the digitiser
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Claims

1. A SYSTEM FOR LOCATING THE POSITION OF A STYLUS AS DEFINED IN TERMS OF A COORDINATE, DISTANCES ALONG WHICH ARE REPRESENTED BY A FAMILY OF SPACED COORDINATE CONDUCTORS COMPRISING:

(A) MEANS FOR SEQUENTIALLY APPLYING AN IDENTIFYING WAVE TO EACH CONDUCTOR AND FOR CONCURRENTLY GENERATING A FIRST VOLTAGE WAVEFORM OF CHANGING LEVEL;

(B) MEANS FOR PICKING UP ONE OF SAID WAVES IN THE STYLUS FROM AN ADJACENT CONDUCTOR;

(C) MEANS OPERATED BY SAID PICKING UP MEANS FOR STORING THE LEVEL OF THE FIRST WAVEFORM AT THE INSTANT WHEN THE WAVE WAS PICKED UP;

(D) MEANS FOR GENERATING AND APPLYING PLURAL PHASESHIFTED COMPONENTS OF A CYCLIC WAVE IN A REPEATING SEQUENCE TO PLURAL CONDUCTORS IN REPEATING GROUPS AND FOR CONCURRENTLY GENERATING A SECOND WAVEFORM CHANGING IN LEVEL AND INITIATED AT THE TIME THE CYCLIC WAVE PASSES THROUGH A DEFINITE POINT IN ITS CYCLE;

(E) MEANS FOR PICKING UP A COMPOSITE OF THE PHASE SHIFTED COMPONENTS AT THE STYLUS AND DETERMINING THE INSTANT AT WHICH THE COMPOSITE PASSES THROUGH A SIMILAR DEFINITE POINT IN ITS CYCLE;

(F) MEANS OPERATED BY THE LATTER PICKING UP MEANS FOR STORING THE LEVEL OF THE SECOND WAVEFORM AT THE LATTER INSTANT;

AND (G) MEANS FOR COMBINING THE TWO STORED LEVELS TO PRODUCE AN OUTPUT LEVEL PROPORTIONAL TO SAID STORED LEVELS AND REPRESENTING THE POSITION OF THE STYLUS ALONG THAT COORDINATE.