Electrographic system

• US 4,523,654 A
• Filed: 09/14/1983
• Issued: 06/18/1985
• Est. Priority Date: 09/14/1983
• Status: Expired due to Term

• Current Assignee: Frances B. Cuniberti, Scriptel Corporation, Walter T. Krumm
• Original Assignee: Scriptel Corporation
• Inventors: Schlosser, Philip A., Quayle, Stanley F.
• Primary Examiner(s): SCHREYER, STAFFORD
• Application Number:
  US06/532,191
• Time in Patent Office: 643 Days
• Field of Search: 178/19, 178/18, 178/20, 324/71 R, 33/11 M, 346/139 C
• US Class Current: 178/19.06
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

An electrographic system utilizing a transparent resistive layer which operates in conjunction with a stylus or cross hair cursor excited from an a.c. source to develop coordinate defining electrical signals. Through the utilization of a sequence of border switching arrays, the signals may be collected from the resistive surface in a predetermined sequence and submitted in serial fashion to the input of a signal treatment network. As a consequence, only one such network is required to effect operation of the system. The hand-held cursor is formed including a transparent disk carrying cross hairs which is excited from an a.c. source to very accurately locate coordinate positions upon the resistive surface.

Claims

1. An electrographic system comprising:

an electrically insulative substrate;

a resistive layer exhibiting substantially uniform electrical resistance supported upon said insulative substrate and having an operational region extending in a x-coordinate sense between first and second parallel, spaced-apart border regions, and extending in a y-coordinate sense between third and fourth parallel, spaced-apart border regions;

stylus means for generating localized electromagnetic radiation from an a.c. source to effect the propagation thereof toward said resistive layer from positions selectively spaced therefrom to effect interaction therewith;

a plurality of first, discrete, spaced-apart contacts electrically coupled with said resistive layer at said first border region;

a plurality of second, discrete, spaced-apart contacts electrically coupled with said resistive layer at said second border region;

a plurality of third, discrete, spaced-apart contacts electrically coupled with said resistive layer at said third border region;

a plurality of fourth, discrete, spaced-apart contacts electrically coupled with said resistive layer at said fourth border region;

signal treating means having an input of predetermined impedance for selectively receiving electrical signals generated by said stylus means interaction and present at said first and second contacts to derive x-coordinate signals corresponding with the x-coordinate location of said interaction, and selectively responsive to said electrical signals present at said third and fourth contacts to derive y-coordinate signals corresponding with the y-coordinate location of said interaction;

first discrete low impedance solid state series switches, each coupled between a selected one of said first contacts and said signal treating means input and actuable to effect conveyance of said electrical signals thereto;

second discrete low impedance solid state series switches, each coupled between a selected one of said second contacts and said signal treating means input and actuable to effect conveyance of said electrical signals thereto;

third discrete low impedance solid state series switches, each coupled between a selected one of said third contacts and said signal treating means input and actuable to effect conveyance of said electrical signals thereto;

fourth discrete low impedance solid state series switches, each coupled between a selected one of said fourth contact and said signal treating means input and actuable to effect conveyance of said electrical signals thereto;

first discrete low impedance solid state grounding switches, each coupled between a select one of said first contacts and ground and actuable to effect coupling of said select first contact with said ground;

second discrete, low impedance solid state grounding switches, each coupled between a select one of said second contacts and ground and actuable to effect coupling of said select second contact with said ground;

third discrete, low impedance solid state grounding switches, each coupled between a select one of said third contacts and ground and actuable to effect coupling of said select third contact with said ground;

fourth discrete, low impedance solid state grounding switches, each coupled between a select one of said fourth contacts and ground and actuable to effect coupling of said select fourth contact with said ground; and

control means having output means coupled with said first, second, third and fourth series switches and said first, second, third and fourth grounding switches for actuating said first series switches while simultaneously actuating said second grounding switches during a first data mode, for actuating said second series switches while simultaneously actuating said first grounding switches during a second data mode, for actuating said third series switches while simultaneously actuating said fourth grounding switches during a third data mode, and for actuating said fourth series switches while simultaneously actuating said third grounding switches during a fourth data mode.

2. The electrographic system of claim 1 in which said control means effects said first, second, third and fourth data mode switch actuations in a predetermined repetitive sequence.

3. The electrographic system of claim 1 in which said first, second, third, and fourth series switches exhibit an impedance, when actuated, of less than about five ohms.

4. The electrographic system of claim 1 in which said stylus means is a hand manipular, self-contained, battery powered transmitting antenna operative in a frequency range of between about 10 KHz and 1 MHz.

5. The electrographic system of claim 1 in which:

said substrate is substantially transparent; and

said resistive layer is a deposited oxide of metal selected from the group comprising tantalum, indium, tin, antimony and mixtures thereof.

6. The electrographic system of claim 1 in which said signal treating means comprises:

current to voltage converter means having an input of near ground potential for receiving said electrical signals and having an alternating voltage output corresponding therewith; and

converter means for converting said alternating voltage output to a constant voltage output.

7. The electrographic system of claim 6 in which:

said signal treating means includes analog to digital converter means for converting said constant voltage output to digitally characterized signals; and

said control means includes processor means having an input for receiving said digitally characterized signals during each said data mode and responsive to treat said digitally characterized signals to generate digital x-coordinate signals corresponding with the ratio of the difference of said digital characterized signals received during said first and second data modes divided by the sum thereof, said processor means proving said x-coordinate signals at an output thereof.

8. The electrographic system of claim 7 in which said processor means is responsive to treat said digitally characterized signals to generate y-coordinate signals corresponding with the ratio of the difference of said digitally characterized signals received during said third and fourt data modes divided by the sum thereof, said processor means providing said y-coordinate signals at said output.

9. The electrographic system of claim 8 in which:

said resistive layer has a predetermined operational border extending adjacent said first, second, third and fourth border regions; and

said processor means is responsive to said x-coordinate signals and said y-coordinate signals having values representing positions of said stylus means outwardly of said border to effect the negation thereof.

10. The electrographic system of claim 1 in which said first, second, third and fourth spaced-apart contacts are elongate conductive pads of predetermined length mutually spaced-apart by about said predetermined length.

11. The electrographic system of claim 1 in which:

said control means effects said first, second, third and fourth data mode switch actuations in a predetermined repetitive sequence; and

said first, second, third, and fourth series switches exhibit an impedance, when actuated, of less than about five ohms.

12. An electrographic system comprising:

an electrically insulative substrate;

a resistive layer exhibiting substantially uniform electrical resistance supported upon said insulative substrate and having an operational region extending in a x-coordinate sense between first and second parallel, spaced-apart border regions, and extending in a y-coordinate sense between third and fourth parallel, spaced-apart border regions;

cursor means including an electrically conductive transparent disk having a cross hair indicia formed thereon positionable adjacent said resistive layer;

means for exciting said cursor means from an a.c. source to generate localized electromagnetic radiation from said disk to effect an interaction with said resistive layer;

a plurality of first, discrete, spaced-apart contacts electrically coupled with said resistive layer at said first border region;

a plurality of second, discrete, spaced-apart contacts electrically coupled with said resistive layer at said second border region;

a plurality of third, discrete, spaced-apart contacts electrically coupled with said resistive layer at said third border region;

a plurality of fourth, discrete, spaced-apart contacts electrically coupled with said resistive layer at said fourth border region;

signal treating means having an input for selectively receiving electrical signals generated by said cursor means interaction and present at said first and second contacts to derive output signals corresponding therewith, and selectively receiving said electrical signals present at said third and fourth contacts to derive output signals corresponding therewith;

solid state switching means for coupling said first contacts in signal transferring relationship with said signal treating means input while effecting a mutual, open circuit isolation of said third and fourth contacts, for coupling said second contacts in signal transferring relationship with said signal treating means input while effecting a mutual, open circuit isolation of said third and fourth contacts, for coupling said third contacts in signal transferring relationship with said signal treating means input while effecting a mutual, open circuit isolation of said first and second contacts, and for coupling said fourth contacts in signal transferring relationship with said signal treating means input while effecting a mutual, open circuit isolation of said first and second contacts; and

control means responsive to said output signals for deriving x-coordinate signals corresponding with the x-coordinate location of said interaction and y-coordinate signals corresponding with the y-coordinate location of said interaction.

13. The system of claim 12 in which said signal treating means comprises:

current to voltage converter means having an input of predetermined impedance for receiving said electrical signals and having an alternating voltage output corresponding therewith;

converter means for converting said alternating voltage; and

means for converting said output signals to corresponding digital form.

14. The system of claim 13 in which said control means is responsive to said signals in digital form corresponding with each said first and second border regions for deriving said x-coordinate signals corresponding with the ratio of the difference of said output signals divided by the sum thereof.

15. The system of claim 13 in which said control means is responsive to said output signals in digital form correspnding with each said third and fourth border regions for deriving said y-coordinate signals corresponding with the ratio of the difference of said output signals divided by the sum thereof.

16. The electrographic system of claim 12 in which:

said resistive layer has a predetermined operational border extending adjacent said first, second, third and fourth border regions; and

said processor means is responsive to said x-coordinate signals and said y-coordinate signals having values representing positions of said stylus means outwardly of said border to effect the negation thereof.