Digitizer pad

• US 4,810,992 A
• Filed: 04/19/1988
• Issued: 03/07/1989
• Est. Priority Date: 01/17/1986
• Status: Expired due to Term

• Current Assignee: Interlink Electronics Incorporated
• Original Assignee: Interlink Electronics Incorporated
• Inventors: Eventoff, Franklin N.
• Primary Examiner(s): Goldberg, E. A.
• Assistant Examiner(s): Lateef, Marvin M.
• Application Number:
  US07/183,118
• Time in Patent Office: 322 Days
• Field of Search: 338/99, 338/114, 338/100, 338/69, 84/DIG. 7, 178/18, 178/19, 178/28, 340/365 A, 340/711, 340/712, 340/825.89
• US Class Current: 338/99
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

A digitizer pad includes at least two base plys, each having thereon at least three terminals, a resistor ply disposed between two of the terminals with a plurality of conductors extending from each resistor ply which are spaced apart and interleaved with a plurality of conductors extending from each third terminal. The respective base plys'"'"' conducting surfaces face each other and are sandwiched about a nonconductive ply that includes a pressure sensitive conductive layer on each side, the area of which layer covers a portion of the area encompassed by the interleaved conductors on each base ply. The resistor plys and conductors on each base ply are at predetermined angles to those on the base ply, hence the conductors of each base ply form two predefined axes. A voltage source is sequentially coupled, by suitable switching means, across a selected pair of terminals on each ply to measure the selected location along the parameter dimension defined by the terminals across which the voltage source is coupled. Hence, the spatial location of a force applied to the digitizer pad along any one or more axes in a plane is determinable as well as the magnitude of the force applied generally perpendicular to that plane.

Claims

1. A digitizer pad apparatus comprising:

an insulative ply,

a first conducting ply on one side of the insulative ply;

a second conducting ply on the other side of the insulative ply opposite the one side;

two base plys, each base ply having thereon;

(a) at least three terminals,

(b) a resistor ply coupled between two of the terminals,

(c) a plurality of first conductors extending from the resistor ply,

(d) a plurality of second conductors coupled to the third terminal interleaved between but spaced apart from the plurality of first conductors defining a pad area,

the base plys positioned with their respective pad areas in facing relationship to each other and the insulative ply therebetween, with the first and second conducting plys in facing relationship to the pad areas of the respective base plys and at least one of the first and second conducting plys being a pressure sensitive semiconductor ply.

2. The digitizer pad of claim 1, wherein the first and second conductors on each base ply are orthogonal to each other.