Electrical switch device and process for manufacturing same
AssigneeAptek Williams, Inc.
InventorTom O. Martin
Life of this patent
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Abstract
An electrical switch device includes a thick film switch element having a low temperature co-fired dielectric substrate, electrical conductor tracks embedded in the substrate and having a surface substantially flush with the substrate surface, and wiper contacts in sliding engagement with the conductor tracks. The switch is useful for position sensors, throttle controls, and digital encoders. A method of manufacturing a thick film switch element includes providing a low temperature co-fired dielectric substrate in a green state, depositing an electrically conductive material onto a face of the substrate, pressing the conductive material into the substrate until the material is substantially flush with the substrate face, and then firing the substrate and conductive material.
Claims39
An electrical switch device having at least two electrical conductors engageable by a wiper contact slidable over said conductors, made by the process of:
- (a) providing a low temperature co-fired dielectric substrate in a green state;
- (b) depositing an electrically conductive material onto a face of said substrate to form said electrical conductors;
- (c) pressing said electrical conductors into said substrate until said conductors are substantially flush with said substrate face;
- (d) after step (c), firing said substrate with said flush electrical conductors at a temperature sufficient to sinter said substrate but less than the melting point of said electrical conductors, wherein said electrical conductors and said substrate have a similar shrinkage during firing such that after firing said electrical conductors are substantially flush with substrate surface;
- and
- (e) assembling the electrical wiper in sliding engagement with said conductors.
An electrical switch device comprising:
- a wiper contact;
- and
- a switch element comprising a low temperature co-fired dielectric substrate having a top surface, at least one conductor track having a surface adapted for sliding engagement by the wiper contact;
- wherein the at least one electrical conductor track is embedded into the surface of the substrate, and the surface of the substrate and the surface of the conductor track are substantially flush.
An integrated position sensor and validation device, said device comprising:
- (a) a device housing;
- (b) a wiper inside said housing adapted for mechanical coupling to a movable object external to said housing, said wiper having a plurality of wiper contacts;
- and
- (c) a switch element inside the housing and proximate to the wiper, the switch element including:
- (1) a low temperature co-fired dielectric substrate having a top surface,
- (2) a plurality of spaced apart electrical conductor tracks each having a surface for engagement with at least one of the wiper contacts, at least three of said electrical conductors positioned with respect to the wiper contacts and cooperating with the wiper contacts to form a single-pole, double-throw switch to provide a validation signal responsive to the position of the movable object, and at least one of said electrical conductor tracks positioned with respect to the wiper contacts to form a common collector for a variable resistor;
- and
- (3) a thick film resistor on the surface of the substrate having opposing ends disposed over electrical conductor pads and cooperating with wiper contacts in sliding engagement with the resistor and the common collector to form a variable resistor to provide a position signal responsive to the position of the movable object;
- wherein the surface of the conductor tracks and the conductor pads are substantially flush with the surface of the substrate.
A method of manufacturing a switch element for an electrical switch having at least two electrical conductors engageable by an electrical wiper slidable over said conductors, comprising the steps of:
- (a) providing a low temperature co-fired dielectric substrate in a green state;
- (b) depositing an electrically conductive material onto a face of said substrate to form said electrical conductors, said material having shrinkage similar to said substrate,
- (c) pressing said electrical conductors into said substrate until said conductors are substantially flush with said substrate face,
- (d) after step (c), firing said substrate with said flush electrical conductors at a temperature sufficient to sinter said substrate but less than the melting point of said electrical conductors;
- and
- (e) placing an electrical wiper on said substrate in electrical contact with at least two of said conductors.
A method of manufacturing an electrical sensor switch, of the type having a substrate, at least two electrical conductors on said substrate and spaced apart to form a gap therebetween, and a contactor in sliding engagement with said conductors and through said gap between said conductors, comprising the steps of:
- (a) providing a first layer of low temperature co-fired dielectric substrate in a green state;
- (b) depositing an electrically conductive material on a face of said first layer of substrate in at least two spaced apart areas to form said electrical conductors having a gap therebetween, said conductive material having similar firing shrinkage characteristics as said substrate;
- (c) providing a second layer of a dielectric material in a green state;
- (d) placing the first layer on the second layer with the electrical conductors remaining exposed;
- (e) pressing said first and second layers together;
- (f) pressing said electrical conductors into said first layer;
- (g) firing the layers and electrical conductors;
- (h) depositing electrically conductive traces on the first layer electrically connecting each of said conductors to terminals on the layer;
- and
- (i) placing a slideable contactor over said electrical conductors.
A method of manufacturing an electrical switch board having at least two electrical conductors thereon, said conductors being engageable by an electrical wiper slidable over said board to make and break a circuit containing said conductors, comprising the steps of:
- (a) providing a first sheet of a low temperature co-fired dielectric in a green state;
- (b) depositing an electrically conductive material onto one face of said first sheet to form said electrical conductors, said conductive material having similar firing shrinkage characteristics as said substrate;
- (c) providing a second sheet of a dielectric material in a green state;
- (d) pressing said first and second sheets together with a pressure sufficient to displace said electrical conductors into said first sheet until said conductors are substantially flush with said one face;
- (e) firing the sheets laminated in step (d).
Dependencies are inferred from the claim text.