Coordinate inputting system with provision for erroneous input detection

• US 4,819,194 A
• Filed: 06/03/1987
• Issued: 04/04/1989
• Est. Priority Date: 06/18/1986
• Status: Expired due to Fees

• Current Assignee: Omron Tateisi Electronics Co. (Omron Corporation)
• Original Assignee: Omron Tateisi Electronics Co. (Omron Corporation)
• Inventors: Sato, Hideki, Koizumi, Haruyuki, Omae, Koichi, Hashizume, Shinichi
• Primary Examiner(s): Malzahn, David H.
• Application Number:
  US07/056,892
• Time in Patent Office: 671 Days
• Field of Search: 364/556, 364/709, 364/709.11, 178/18
• US Class Current: 700/293
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

In this coordinate inputting system, a coordinate inputting sheet is provided for detecting an axial coordinate, and this includes a sheet body with a resistive surface laid over one of its sides, a pair of mutually substantially parallel edge electrodes extending along opposite edges of this resistive surface which are for having voltage applied between them, and several intermediate electrodes, substantially mutually parallel and substantially parallel to the pair of edge electrodes, and extending along the resistive surface bewteen the pair of edge electrodes in a mutually spaced relationship. Also, there are provided a device for processing information by obtaining voltage divided at an input point selected by pen contact against the coordinate inputting sheet as axial coordinate information, a device for storing in advance reference information relating to the voltages on the electrodes when the voltage is applied between the edge electrodes, a device for detecting which of the electrodes straddle the input point by comparing the axial coordinate information obtained from the information processing device with the reference information, and a device for determining the validity of input operation according to the result of comparison between the voltages upon the electrodes which straddle the input point and the reference information. Optionally, the reference information may include the voltages on the electrodes when the voltage is applied between the edge electrodes, and the voltage differences between neighboring ones of the electrodes.

Claims

1. A coordinate inputting system, comprising:

at least one coordinate inputting sheet, comprising a sheet body having a resistive layer, a pair of substantially parallel edge electrodes extending along opposite edges of said resistive layer and a plurality of intermediate parallel electrodes, which are substantially parallel to said pair of edge electrodes, and extend along said resistive layer between said pair of edge electrodes in a mutually spaced relationship;

means for applying a voltage across said pair of edge electrodes to develop voltages at each of said electrodes;

a pen for contacting said resistive layer of said sheet to select an input point;

means for storing reference information relating to voltages on said electrodes when said voltage is applied across said edge electrodes and in the absence of any contact between said pen and said sheet;

means for determining as axial coordinate information a divided voltage at an input point where said pen contacts with said sheet;

means for determining which of said electrodes straddle said input point by comparing said axial coordinate information with said reference information; and

means for determining the validity of an input operation by comparing the voltages upon said straddling electrodes with said reference information.

2. A coordinate inputting system according to claim 1, wherein said reference information includes the voltages on said electrodes when said voltage is applied between said edge electrodes, and the voltage differences between neighboring ones of said electrodes.

3. A coordinate inputting system according to claim 1 wherein at least two of said coordinate inputting sheets are provided with the electrodes of one of said sheets being angled relative to the electrodes of another of said sheets to provide X and Y coordinate input data.

4. A coordinate inputting system according to claim 3 wherein the electrodes of one of said sheets are perpendicular to the electrodes of another of said sheets.

5. A coordinate inputting system as in claim 3 further comprising a switchover circuit for sequentially supplying a voltage to said pair of edge electrodes of each of said sheets.

6. A coordinate inputting system as in claim 1 further comprising means responsive to said validity determining means for indicating an invalid input operation.

7. A coordinate inputting system comprising:

a first coordinate input sheet comprising a first sheet body having a first resistive layer, a first pair of substantially parallel edge electrodes extending along opposite edges of said first resistive layer, and a first plurality of intermediate parallel electrodes, which are substantially parallel to said first pair of edge electrodes and extend along said first resistive layer between said first pair of edge electrodes in mutually spaced relationship;

a second coordinate input sheet comprising a second sheet body having a second resistive layer, a second pair of substantially parallel edge electrodes extending along opposite edges of said second resistive layer, and a second plurality of intermediate parallel electrodes, which are substantially parallel to said second pair of edge electrodes and extend along said second resistive layer between said second pair of edge electrodes in mutually spaced relationship, the electrodes of said second sheet being substantially perpendicular to the electrodes of said first sheet;

means for sequentially applying a voltage across said first and second pair of edge electrodes to sequentially develop voltages at the electrodes of said first and second sheets;

a pen for contacting said first and second sheets to select an input point having X and Y coordinates;

means for storing reference information relating to the voltages on said electrodes of each of said first and second sheets when a voltage is applied across the edge electrodes thereof and in the absence of any contact between said pen and said sheets;

means for determining, as axial coordinate information, for each of said sheets, a divided voltage at an input point where said pen contacts with said sheets;

means for determining, for each of said sheets, which of the electrodes thereof straddle said input point by comparing the axial coordinate information of a sheet with the reference information for the same sheet; and

,

means for determining the validity of an input operation by comparing the voltage upon the straddling electrodes of one of said sheets with said reference information for the same sheet.