Fiber optics condition sensor and method of making same

Abstract

A fiber optics condition sensor and a method of producing such a device is disclosed. A bundle of optical fibers provides a planar termination on one end and is bifurcated to provide one group adapted to be connected to a light source and another group adapted to be connected to a detector. A shallow, curved, thin metallic diaphragm provides a central portion movable toward and away from the termination in response to the condition being sensed in order to vary the light reflected to the detector and therefore produce a detector output signal which is a function of the changes in conditions being sensed. The diaphragm may be formed of bimetal for sensing temperature conditions, or of a homogeneous metal to sense pressure. The curvature formed in the diaphragm is selected to provide movement of the central portion of the diaphragm through a distance selected to match the reflective light intensity versus spacing curve so that the system provides substantially the maximum response over a predetermined range of conditions being sensed. Variations in the curvature of the diaphragm are compensated for in the mounting of the diaphragm with respect to the fiber optics termination so as to ensure maximum response in the total system.