Abstract: The cost and complexity of an electronic pressure sensitive transducer are decreased by constructing such a transducer directly on a printed circuit board containing support electronics. Conductive traces are formed on the printed circuit board to define a contact area. A flexible substrate having an inner surface is positioned over the contact area. An adhesive spacer, substantially surrounding the contact area, attaches the flexible substrate to the printed circuit board. At least one resistive layer is deposited on the flexible substrate inner surface. In use, the resistive layer contacts at least two conductive traces in response to pressure applied to the flexible substrate to produce an electrical signal indicative of applied pressure.

Abstract: The cost and complexity of an electronic pressure sensitive transducer are decreased by constructing such a transducer directly on a printed circuit board containing support electronics. Conductive traces are formed on the printed circuit board to define a contact area. A flexible substrate having an inner surface is positioned over the contact area. An adhesive spacer, substantially surrounding the contact area, attaches the flexible substrate to the printed circuit board. At least one resistive layer is deposited on the flexible substrate inner surface. In use, the resistive layer contacts at least two conductive traces in response to pressure applied to the flexible substrate to produce an electrical signal indicative of applied pressure.

Abstract: A pressure transducer includes a base ply, a resistance ply disposed on the base ply and at least two spaced apart conductors juxtaposed in relation to the resistance ply whereby at least one of the conductors may be pressed against the resistance ply. The resistance ply is made by spraying or silk screening a mixture of a continuous matrix conductive resin and a stannous oxide particulate and then curing the composition to form a solid resistance ply having a surface with a multiplicity of micro-protrusions formed by the stannous oxide particulate.

Abstract: A pressure transducer includes a base ply, a resistance ply disposed on the base ply and at least two spaced apart contacts juxtaposed in relation to the resistance ply whereby at least one of the contacts may be pressed against the surface of the resistance ply. The resistance ply is made by spraying or silk screening a mixture of resin resistive to electrical conduction and a conductive particulate and then curing the composition to form a thin resistance ply having a surface with a multiplicity of micro-protrusions formed by the conductive particulate. The ratio of conductive particulate to resin is such that the mean distance between microprotrusions is greater than about five time the size of the conductive particles. The particles are in the range of about 0.5 to 10 microns and the resin layer is about is 0.4 to 0.8 microns thick.

Abstract: A pointing device may be directly soldered to a printed circuit board. In one embodiment, a bottom substrate defines a sensing region with a plurality of interdigitated conductive trace regions. Each trace region includes interdigitated common and sense traces. At least one via passes through the bottom substrate for each trace. Each via supports a conductive path from one trace to at least one lead element. Each lead element is solderable to a printed circuit board. A flexible substrate is constructed from a heat resistant polymer. The flexible substrate has a resistive layer deposited on a bottom side. A raised pedestal is formed on the bottom substrate top face around at least a portion of the sensing region. The pedestal separates the interdigitated conductive traces from the flexible substrate resistive layer. A button on a keypad membrane may be used to depress the flexible substrate onto the trace region.

Abstract: An adaptive keypad which has one or more keys includes, for each key, a pressure transducer positioned below a semi-rigid faceplate where the pressure transducer has a resistance which decreases as the pressure compressing the transducer increases. The transducer is connected in series with a capacitor to define an RC circuit for each key. Each RC circuit has a charge time proportional to the pressure applied to the key. A time capture circuit initially and thereafter intermittently, obtains the charge time for each RC circuit for each key and computes a conductance value from that time. The initial conductance value is stored in a memory. A comparing circuit intermittently compares the initial conductance value with each subsequent conductance value generated for a key. If the comparison value generated is greater than a predefined amount, a signal is generated indicating that a key has been depressed.