Patent ID: 7122818

Claim:
An external force detecting device, comprising: a plurality of optical displacement sensors, at least one of said plurality of optical displacement sensors including: a light source disposed at one of a reference object and a measurement object; a light receiving means disposed at the other one thereof at which the light source is not disposed, and functioning to receive light emitted from the light source thereby measuring displacement of the measurement object relative to the reference object with respect to two-axis directions in a plane perpendicular to an optical center axis of the light emitted from the light source; and an optical fiber disposed between the light source and the light receiving means in such a manner as to keep its relative position steady with respect to the light source, the optical fiber functioning to conduct the light, emitted from the light source so that the light can be received by the light receiving means, wherein an external force applied to the measurement object is detected based on a signal of measurement results by the optical displacement sensor, and wherein said plurality of optical displacement sensors are provided such that the two-axis directions with respect to which displacement is measured differ among the optical displacement sensors, and wherein the plurality of optical displacement sensors share one light source in common, with one optical fiber branching into a number equal to a number of light receiving means.