Force sensing dome switch
View Patent ↗The force sensing dome switch is configured to simultaneously, or nearly simultaneously, close or open two separate circuits. For one of these circuits, the force sensing dome switch acts as a variable resistor whose value is controlled by applied force. Each force sensing dome switch is disposed upon a printed circuit board (PCB) comprising two separate circuits. An example force sensing dome switch comprises: a conductive dome in conductive contact with a first trace of a first circuit, the conductive dome is configured to make conductive contact with a second trace of the first circuit when pressed down; and a force-sensing resistor element positioned between the PCB and the conductive dome, the force-sensing resistor element overlays a pair of traces of a second circuit and is configured to conductively connect the pair of traces when pressed against the PCB by the conductive dome. The force-sensing resistor element is a layer of material whose resistance changes when force is applied.
1. A force sensing dome switch disposed upon a printed circuit board comprising a first circuit and a second circuit, the force sensing dome switch comprising:
a conductive dome in conductive contact with a first trace of the first circuit, the conductive dome is configured to make conductive contact with a second trace of the first circuit when pressed down; and
a force-sensing resistor element positioned between the printed circuit board and the conductive dome, the force-sensing resistor element overlays a pair of traces of the second circuit and is configured to conductively connect the pair of traces when pressed against the printed circuit board by the conductive dome;
wherein the force-sensing resistor element is a layer of material whose resistance changes when force is applied; and
wherein the force-sensing resistor element has a hole therein, the hole is configured so no portion of the force-sensing resistor element overlays the second trace of the first circuit.
2. The force sensing dome switch of claim 1 , further comprising a spacer positioned between the conductive dome and the force-sensing resistor element, the spacer has a hole therein configured so no portion of the spacer overlays the second trace of the first circuit.
3. The force sensing dome switch of claim 1 , further comprising a spacer positioned between the force-sensing resistor element and the printed circuit board, the spacer has a hole therein configured so no portion of the spacer overlays the second trace of the first circuit.
4. The force sensing dome switch of claim 1 , wherein the conductive dome is fabricated from an electrically conductive and resilient material.
5. A force sensing dome switch disposed upon a printed circuit board comprising a first circuit and a second circuit, the force sensing dome switch comprising:
a conductive dome in conductive contact with portions of a first trace of the first circuit, the conductive dome is configured to make conductive contact with a second trace of the first circuit when pressed down; and
a force-sensing resistor element positioned between the printed circuit board and the conductive dome, the force-sensing resistor element overlays a pair of traces of the second circuit and is configured to conductively connect the pair of traces when pressed against the printed circuit board by the conductive dome;
wherein the force-sensing resistor element is a layer of material exhibiting varying resistance in response to applied force;
wherein the force-sensing resistor element has a hole therein, the hole is configured so no portion of the force-sensing resistor element overlays the second trace of the first circuit.
6. The force sensing dome switch of claim 5 , further comprising a spacer positioned between the conductive dome and the force-sensing resistor element, the spacer has a hole therein configured so no portion of the spacer overlays the second trace of the first circuit.
7. The force sensing dome switch of claim 5 , further comprising a spacer positioned between the force-sensing resistor element and the printed circuit board, the spacer has a hole therein configured so no portion of the spacer overlays the second trace of the first circuit.
8. The force sensing dome switch of claim 5 , wherein the conductive dome is fabricated from an electrically conductive and resilient material.
9. A force sensing dome switch disposed upon a printed circuit board comprising a first circuit and a second circuit, the force sensing dome switch comprising:
a conductive dome comprising a first end and a second end, the first end and the second end of the conductive dome are in conductive contact with a first portion and a second portion, respectively, of a first trace of the first circuit, the conductive dome is configured so that pressing down on the conductive dome causes a portion thereof to make conductive contact with a second trace of the first circuit; and
a force-sensing resistor element positioned between the printed circuit board and the conductive dome, the force-sensing resistor element overlays a pair of traces of the second circuit and is configured to conductively connect the pair of traces when pressed against the printed circuit board by the conductive dome;
wherein the force-sensing resistor element is a layer of material exhibiting varying resistance in response to applied force; and
wherein the force-sensing resistor element has a hole therein, the hole is configured so no portion of the force-sensing resistor element overlays the second trace of the first circuit.
10. The force sensing dome switch of claim 9 , further comprising a spacer positioned between the conductive dome and the force-sensing resistor element, the spacer has a hole therein configured so no portion of the spacer overlays the second trace of the first circuit.
11. The force sensing dome switch of claim 9 , further comprising a spacer positioned between the force-sensing resistor element and the printed circuit board, the spacer has a hole therein configured so no portion of the spacer overlays the second trace of the first circuit.
12. The force sensing dome switch of claim 9 , wherein the conductive dome is fabricated from an electrically conductive and resilient material.
13. The force sensing dome switch of claim 9 , wherein the pair of traces of the second circuit are positioned between the first portion and the second portion of the first trace of the first circuit, the pair of traces of the second circuit are positioned around the second trace of the first circuit.