Movable contact element and switch using the same
A movable contact element includes a cover sheet to which a movable contact having a dome shape is bonded and which is stacked on a top surface of a pressure sensitive conductive sheet. The movable contact element is bonded to a top surface of a substrate having a fixed contact formed thereon, thereby forming a switch. Through the construction, it is possible to obtain the movable contact element, which has a simple construction and can perform various operations, and the switch using the same.
1. A switch comprising:
a substrate;
a movable contact element including: a movable contact having a dome shape;
a cover sheet having the movable contact bonded to its lower surface; and
a pressure sensitive conductive sheet having the cover sheet stacked on its top surface;
and a fixed contact that is formed on a top surface of the substrate such that a top surface of the fixed contact faces a lower surface of the pressure sensitive conductive sheet, the pressure sensitive conductive sheet including a low resistor layer and a high resistor layer having a larger resistance value than the low resistor layer,
wherein
the fixed contact has an outer-periphery fixed contact, a first central fixed contact and a second central fixed contact,
the pressure sensitive conductive sheet comes in contact with the first central fixed contact and the second central fixed contact by deforming the movable contact elastically,
a first resistor element is connected to the first central fixed contact, and
a second resistor element is connected to the second central fixed contact, the second resistor element having a larger electric resistance value than the first resistor element.
2. The switch of claim 1 , wherein the low resistor layer, where carbon powder is dispersed into synthetic resin, has a sheet resistance value of 0.5 to 30 kΩ/□.
3. The switch of claim 1 , wherein the high resistor layer has surface irregularities and has a sheet resistance value of 50 kΩ/□to 5 MΩ/□.
4. The switch of claim 1 , wherein each of the first central fixed contact and the second central fixed contact has a comb shape such that teeth of the first central fixed contact and the second central fixed contact are alternately arranged with each other with a predetermined gap therebetween.
5. The switch of claim 1 , wherein the pressure sensitive conductive sheet and the outer-periphery fixed contact are electrically connected to each other at all times.