Henry Si Ng

US Patent:

44764634, Oct 9, 1984

Filed:

Aug 24, 1981

Appl. No.:

6/295495

Inventors:

Henry H. Ng - Chestnut Hill MA
Bela R. Hatvany - London, GB2

Assignee:

Interaction Systems, Inc. - Newtonville MA

International Classification:

G09G 100

US Classification:

340712

Abstract:

A display device locates a touch anywhere on a conductive display faceplate by measuring plural electrical impedances of the faceplate conductive coating. The impedances are at electrodes located on different edges of the faceplate. A touch locating circuit determines the location of a touch using known pulsed signals and, in another embodiment, using a tuned measuring signal.

US Patent:

43743811, Feb 15, 1983

Filed:

May 1, 1981

Appl. No.:

6/259614

Inventors:

Henry H. Ng - Chestnut Hill MA
Frederick R. Schmidt - Marshfield MA

Assignee:

Interaction Systems, Inc. - Newtonville MA

International Classification:

G06F 314
G09F 932

US Classification:

340711

Abstract:

A touch terminal identifies a single user-selectable, touch-responsive pad element on the display screen for user communication with a data processing system. The terminal makes the identification in response to the durations of pulse signals which vary according to the touch-selection condition of the pad elements. A multiple-step technique of repetitively measuring the signal durations relative to reference values attains essentially error-free pad selection. The operation includes the updating of the reference values of the pulse-signal durations.