Patent ID: 7355720
Filing Date: 2008-04-08
Classification: G01H,H04R

Abstract:
1. An optical displacement sensing apparatus, comprising: (a) a vertical-cavity surface-emitting laser (VCSEL) further comprising a first optical cavity with an active region therein to produce a beam of lasing light; (b) a membrane located proximate to the VCSEL to receive the beam of lasing light and to reflect a portion of the beam of lasing light back into the VCSEL through an output mirror of the VCSEL, with the membrane and the output mirror forming a second optical cavity which is coupled to the first optical cavity to produce a change in intensity of the beam of lasing light in response to a displacement of the membrane; and (c) a photodetector to detect the change in intensity of the beam of lasing light from the VCSEL and to generate therefrom an electrical output signal which varies with the displacement of the membrane.