Character recognition device

• US 4,493,104 A
• Filed: 12/11/1981
• Issued: 01/08/1985
• Est. Priority Date: 12/11/1981
• Status: Expired due to Term

• Current Assignee: Moore Business Forms Inc.
• Original Assignee: Moore Business Forms Inc.
• Inventors: Lukis, Lawrence J., Duhig, Gerard P.
• Primary Examiner(s): Boudreau, Leo H.
• Application Number:
  US06/329,807
• Time in Patent Office: 1,124 Days
• Field of Search: 178/18, 178/19, 178/20, 382/13, 382/3, 382/59
• US Class Current: 382/315
• CPC Class Codes: G06F 2203/04113 Peripheral electrode pattern in resistive digitisers, i.e. electrodes at the periphery of the resistive sheet are shaped in patterns enhancing linearity of induced field
• CPC Class Codes: G06V 10/12 Details of acquisition arrangements; Constructional details thereof

Abstract

This invention is concerned with a character recognition device which includes a writing pad having a pair of sheets with one of the sheets comprising an area of high resistivity and the other one of the sheets comprising a layer of conductive material, the sheets being normally electrically insulated from one another but adapted to be brought into contact with one another by application of writing pressure by a writing implement upon the writing pad, the sheets being adapted to be connected to an electrical switching circuit whereby current is caused to flow through the pad along two alternate paths, wherein the high resistivity and the conductive sheet are separated by a layer of reticulated material and the conductive material is sufficiently elastomeric to provide good continuous electrical contact between the sheets when writing pressure is applied.

Claims

1. A character recognition device comprising a writing pad having a pair of sheets and a layer of reticulated material with reticules, one of the sheets comprising an area of high resistivity and the other one of the sheets comprising a layer of conductive material, the sheets being normally electrically insulated from one another while being constructed and arranged to be brought into contact with one another by application of writing pressure by a writing implement upon the writing pad, the sheets being adapted to be connected to an electrical switching circuit whereby current is caused to flow through the pad along two alernate paths and to a recognition circuit to recognize written characters by virtue of the change in electrical voltages in the alternate paths, the high resistivity sheet and the conductive sheet being separated by the layer of reticulated material and the conductive material being elastomeric and being sufficiently elastic to deform through the reticules of the reticulated material to provide continuous electrical contact between the sheets through the whole length of a writing stroke with said writing implement.

2. A character recognition device according to claim 1 wherein a protective layer of thermoplastic film is provided to protect the elastomeric layer.

3. A character recognition device according to claim 1 wherein the reticulated material is a layer of knitted fabric.

4. A character recognition device according to claim 1 wherein the reticulated material is a lattice sheet of small thicknesses of thermoplastic material.

5. A character recognition device comprising a writing pad having a pair of sheets, one of the sheets comprising an area of high resistivity and the other one of the sheets comprising a layer of conductive material, the sheets being normally electrically insulated from one another while being constructed and arranged to be brought into contact with one another by application of writing pressure by a writing implement upon the writing pad, the sheets being adapted to be connected to an electrical switching circuit whereby current is caused to flow through the pad along two alternate paths and to a recognition circuit to recognize written characters by virtue of the change in electrical voltages in the alternate paths, the high resistivity sheet and the conductive sheet being separated by a layer of reticulated material, the conductive material is sufficiently elastomeric to provide continuous electrical contact between the sheets when writing pressure is applied, and a protective layer of thermoplastic film for protecting said elastomeric conductive material, said layer of reticulated material being welded to said protective layer around the periphery of the layers, the elastomeric conductive material layer being trapped between the reticulated layer and the protective layer.

6. A character recognition device comprising a writing pad having a pair of sheets, one of the sheets comprising an area of high resistivity and the other one of the sheets comprising a layer of conductive material, the sheets being normally electrically insulated from one another while being constructed and arranged to be brought into contact with one another by application of writing pressure by a writing implement upon the writing pad, the sheets being adapted to be connected to an electrical switching circuit whereby current is caused to flow through the pad along two alternate paths and to a recognition circuit to recognize written characters by virtue of the change in electrical voltages in the alternate paths, the high resistivity sheet and the conductive sheet being separated by a layer of reticulated material, the conductive material being sufficiently elastomeric to provide continuous electrical contact between the sheets when writing pressure is applied, said reticulated material being a lattice sheet of small thickness of thermoplastic material, said layer of reticulated material being welded to the protective layer around the periphery of the layer, said elastomeric conductive layer being trapped between the reticulated layer and the protective layer.