Capacitive circuitboard

• US 3,921,167 A
• Filed: 06/14/1974
• Issued: 11/18/1975
• Est. Priority Date: 06/14/1974
• Status: Expired due to Term

• Current Assignee: Jon Edward Fox
• Original Assignee: Jon Edward Fox
• Inventors: Fox, Jon Edward
• Primary Examiner(s): Habecker, Thomas B.
• Assistant Examiner(s): Groody, James J.
• Application Number:
  US05/479,683
• Time in Patent Office: 522 Days
• Field of Search: 340/365C,365R,200 317/DIG.2,261,246,249R,11B 307/88ET,116 179/111E 333/24C 178/DIG.10 200/DIG.1
• US Class Current: 307/116
• CPC Class Codes: H03K 17/98 having a plurality of control members, e.g. keyboard
• CPC Class Codes: H05K 1/0239 Signal transmission by AC coupling
• CPC Class Codes: H05K 1/0286 Programmable, customizable or modifiable circuits by programmable non-printed jumper connections H05K3/222
• CPC Class Codes: H05K 1/0393 Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 1/144 Stacked arrangements of planar printed circuit boards
• CPC Class Codes: H05K 1/162 incorporating printed capacitors
• CPC Class Codes: H05K 2201/09672 Superposed layout, i.e. in different planes

Abstract

Apparatus for use with capacitively coupled keyboard devices is described in which an improved circuitboard which eliminates the necessity of through-plated holes is claimed. At least one flexible dielectric substrate, and one substrate which may be flexible or rigid, are both provided with printed or etched circuit patterns and are used in a sandwich construction with insulative material between them. Pairs of capacitively couplable circuit pads result from this construction and one of the pads in each pair has a capacitively coupled output.

Claims

1. Capacitively coupled circuitboard apparatus, comprising:

a first, flexible, sheet of dielectric material having a first electrically conductive pattern comprising a plurality of adjacent areas of conductive material, said first pattern being on a first surface of said first sheet of dielectric material;

means for connecting at least one of said electrically conductive areas of said first pattern, said connecting means being connected to a source of alternating current voltage, at least one adjacent area of said conductive material of said first pattern being insulated from said alternating current source of voltage by an intervening area of said dielectric material;

a second sheet of dielectric material having, on a first surface thereof, a second pattern of electrically conductive material comprising a plurality of adjacent areas;

at least one of said areas of said second conductive pattern having means for connecting it to an output terminal;

a third, flexible, sheet of dielectric material;

said first, second, and third sheets of material overlying one another in substantially continuous contact with one another in an order in which said third sheet lies between said first and second sheets, with said first and second patterns of conductive material on said first and second sheets, respectively, being in contact with opposite sides of said third sheet;

means for holding said first and second sheets in alignment with one another so that corresponding areas of said conductive material patterns are opposite one another with said at least one area of said first pattern which is insulated from said alternating current source being opposite said at least one electrically conductive area on said second sheet having means for connecting it to said output terminal.

2. Apparatus as described in claim 1, further comprising:

means for holding said first, second and third sheets in contact with one another in said order so that a plurality of corresponding areas of said first and second patterns oF conductive material are in vertical alignment with each other and form capacitances with each other at said corresponding and aligned areas thereof.

3. Capacitively couplable circuit apparatus, comprising:

a first, flexible, sheet of dielectric material having a first electrically conductive pattern comprising a plurality of adjacent areas of conductive material, said first pattern being on a first surface of said first sheet of dielectric material;

at least one of said electrically conductive areas of said first pattern having means for connecting it to a source of alternating current voltage and at least one adjacent area of said conductive material being insulated from said alternating current voltage by an intervening area of said dielectric material;

a second sheet of dielectric material having on a first surface thereof, a second pattern of electrically conductive material comprising a plurality of adjacent areas;

at least one of said areas of said second pattern having means for connecting it to an output terminal;

a third, flexible, sheet of dielectric material;

said first, second, and third sheets overlying one another in substantially continuous contact with one another in an order so that said third sheet lies between said first and second sheets, said first and second patterns of conductive material on said first and second sheets, respectively, being in contact with opposite sides of said third sheet;

means for holding said first and second sheets in alignment with one another so that corresponding areas of said conductive material patterns are opposite one another with said at least one area of said first pattern which is insulated from said alternating current source being opposite said at least one electrically conductive area on said second sheet having said means for connecting it to said output terminal; and

a means for conducting electrical current;

said conducting means being placed in proximity to said first sheet in alignment with at least one of said areas which is connected to said alternating current source of voltage by said connecting means and in alignment with at least one of said areas which is isolated from said alternating current source of voltage, said conducting means substantially overlying said two areas on said first sheet and being on the side of said first flexible dielectric sheet which is opposite the side on which said first pattern of electrically conductive material is placed, said conducting means capacitively coupling said alternating current voltage from said area connected therewith, through said conducting means, to said adjacent conductive area of said first pattern which is insulated from alternating current voltage by said intervening area of said dielectric material.

4. Apparatus as described in claim 3, wherein:

said first and second patterns of conductive material form an M X N crosspoint matrix of conductors, where M and N designate rows or columns in a matrix and are whole numbers, each said M conductor having means for connecting it to said source of alternating current voltage and each said N conductor having means for connecting it to said output terminal.

5. Apparatus as described in claim 4, wherein:

all of said M conductors are on said first flexible dielectric sheet and all of said N conductors are on said second dielectric sheet.