Patent ID: 7369121

Claim:
An input device comprising: a keyboard; and a zoom apparatus embedded on the keyboard, wherein the primary purpose of the zoom apparatus is to zoom an image rendered on a display screen, the zoom apparatus including: an actuator that translates in a first direction to induce the image to zoom in, and the actuator being translatable in a second direction to induce the image to zoom out, and a sensing arrangement including a pair of outer layers, an insulating layer positioned between the outer layers that defines a first aperture and a second aperture, a first contact positioned adjacent the first aperture, and a second contact positioned adjacent the second aperture for detecting movement of the actuator in the first direction and movement of the actuator in the second direction, wherein the insulating layer is formed from an insulative sheet of polyethylene mixed with conductive particles, and wherein the conductive particles are homogenously dispersed in the insulating layer and the net resistance of the sensing arrangement is functionally related to a volume fraction of the particles in ratio to a volume fraction of the insulating layer.