Patent ID: 8013845

Claim:
An optical touch pad for determining a position of an object with respect to an external surface of the optical touch pad, the optical touch pad comprising: a multilayer waveguide comprising: a first waveguide layer bounded on at least one side by a first TIR mirror surface of a first TIR mirror, the first waveguide layer having a first index of refraction; a second waveguide layer bounded on at least one side by a second TIR mirror surface of a second TIR mirror, the second waveguide having a second index of refraction; and wherein the first waveguide layer comprises a rigid layer that comprises the external surface of the optical touch pad and a pliable layer that is directly adjacent to the external layer, wherein the rigid layer is more rigid than the pliable layer and the pliable layer is more pliable than the rigid layer, and wherein when an external force is applied to the external layer that deforms the external layer into the pliable layer, the pliable layer compresses without substantially stressing any other layers within the multilayer waveguide; wherein the multilayer waveguide is configured to direct electromagnetic radiation by total internal reflection to at least one detector to enable the detector to determine the position of the object with respect to the external surface; and wherein the rigid layer and the pliable layer are index of refraction matched.