Apparatus and method for optical clearance determination

DETAILED DESCRIPTION In carrying out one form of my invention, I provide apparatus for optically determining the clearance between an edge of at least one translating member and a relatively stationary second member.
The apparatus includes probe means disposed in relatively fixed position with respect to the stationary second member for directing light from a light source to the edge and for collecting light scattered back from the edge.
The probe means includes first channel means for directing the light to the edge and second channel means generally adjacent to the first channel means for collecting the light scattered back from the edge wherein the first and second channel means are substantially optically isolated from each other.
The probe means includes probe output means responsive to the light scattered back for developing a probe output signal.
Signal processing means is coupled to the probe output means for receiving the probe output signal and developing an intermediate electrical signal substantially representative of the instantaneous clearance between the edge and the second member.
Means responsive to the intermediate signal is provided to provide a representation of the clearance.
Other forms of my invention are provided.