NONNCONTACT TYPE DISTORTION METER FOR OPTICAL FIBERS OR THE LIKE

摘要

PURPOSE:To measure slight distortion by using refractive index, safely without directly contacting the object being examined, by disposing a rotatable sensitive color plate between an analyzer and polarizer placed on the optical axis of a light source, and porviding a photo detector to view said color plate in the rear stage of the analyzer. CONSTITUTION:A pair of polarizer 3 and analyzer 4 are disposed on the optical axis of a light source 1, being spaced from each other and in a manner to form the polarizing surfaces of the two at a right angle, so that a polarizing part 5 such as crossed Nicols is composed. Between the polarizer 3 and analyzer 4 is placed a sensitive color plate 7 in a manner to permit rotation of more than 90 deg.around the optical axis. In response to the interference of polarized light obtained at the polarizing part 5, a sensitive color is obtained in its viewing field. In addition, an objective, condensing element 8 is provided in order to magnify and view the parts of optical fiber A passing between the polarizer 3 and analyzer 4 at a rear stage of the analyzer 4. Further, a photo detector 15 is used to select only blue or yellow color out of the sensitive colors appearing in the viewing field of sensitive color plate 7 after passing through a mask 10, interference filter 13, and eye piece 14, and the brightness of the selected color is measured. Thus, from the brightness and the color, the tensile and compressive distortion may be known.