A force sensor particularly suited for use in an electronic stylus that senses the contact force on its nib for recording pen strokes and handwriting recognition. The sensor has a load bearing member movably mounted for receiving an input force to be sensed, the load bearing member being biased against...http://www.google.de/patents/US7974500?utm_source=gb-gplus-sharePatent US7974500 - Optoelectronic force sensor
