Patent ID: 7463796

Claim:
An optical motion sensing device comprising: a sensor frame defining an opening; a sensor pad disposed in the opening; an optical sensing system adapted to detect an amount of movement of the sensor pad in the sensor frame, the optical sensing system comprising: (a) an optical waveguide positioned within the sensor frame such that the movement of the sensor pad results in the flexing or compressing of the optical waveguide, (b) an optical source device to supply optical energy to a first end of the optical waveguide, and (c) an optical detector to detect an amount of optical energy exiting a second end of the optical waveguide; a load spring attached to at least a portion of the sensor frame and also supporting the sensor pad, and configured to counter at least some of a pressure exerted against the sensor pad, and further adapted to allow a desirable displacement of the sensor pad at a maximum pressure; and an output unit configured to receive a signal indicative of the amount of optical energy exiting the optical waveguide and to generate a measure of the amount of movement of the sensor pad from the received signal.