Patent ID: 6778277
Filing Date: 2004-08-17
Classification: H04N

Abstract:
Apparatus for measuring deflection of a film in a film gate having an aperture illuminated by a primary light source having an output spectrum, comprising:a) a reflective photonic probe mounted in the film gate, the reflective probe having at least one input output fiber and at least one detection optical fiber cleaved and polished flat normal to their fiber axes and mounted parallel and at a fixed spacing relative to each other, and; b) a measurement light source coupled to the reflective photonic probe and emitting a wavelength of light outside of the primary light source's spectrum; c) a photodetector coupled to the reflective photonic probe; d) a narrow bandpass filter located between the photodetector and the reflective photonic probe, the narrow bandpass filter passing the light from the measurement light source and blocking the light from the primary light source; and e) signal processing electronics connected to the photodetector for producing a signal representing the deflection of the film in the film gate as a function of time.