Long travel elastomer keyboard

Claim 1

A keyboard assembly comprising: a first substrate having first switch points, a second flexible substrate having conducting stripes and second switch points, said first and second switch points facing one another in opposed complementary relation, an insulating spacer between said first and second substrates having a plurality of apertures in alignment with said first and second switch points, and a third substrate positioned over said second substrate and having a dome over the locations of each of said first and second switch points to be deformed to provide travel and tactile feedback when a force is applied to a dome for deforming a portion of the second substrate into a spacer aperture for pressing switch points of the first and second substrates together through the insulating spacer aperture, characterized in that the second substrate is formed of a first selected material for receiving said conductive stripes and switch points thereon and has a first selected thickness permitting repeated flexing deformation of the second substrate to a first selected extent over a long service life, the insulating spacer has a selected limited thickness permitting said second substrate portion to be repeatedly deformed to said first selected extent to press first and second switch points together through said insulating spacer apertures throughout said long service life, and said third substrate is formed of a second, elastomeric material and has each dome thereof proportioned to be deformed to a relatively much greater extent to provide long travel and high tactile feedback when said force is applied to a dome for deforming a portion of the second substrate into a spacer aperture for pressing said switch points of the first and second substrates together through the insulating spacer aperture throughout said long service life.