Analyzer for simultaneously determining the rx, photochromic, and hardening characteristics of lenses

Claim 1

In an instrument for measuring and analyzing the prism power, cylinder power, and spherical power of a sample lens, which includes a support means, an incandescent light source mounted on said support means providing a first portion of light along a first axis, a telescopic portion mounted on said support means and positioned along said first axis receiving said first portion of light from said incandescent light source, a sample lens movably positioned to a first position along said first axis, an eyepiece mounted on said support means and positioned along said first axis to receive light transmitted successively through said telescopic portion and said sample lens to allow determination of the prism power, cylindrical power and spherical power of said sample lens; the improvement comprising: a prism mounted on said support means, to receive a second portion of light from said incandescent light source; a polarizing filter having its direction of polarization in a first direction mounted on the light exiting face of said prism; a polarizing analyzer filter having its direction of polarization in a second direction which is crossed 90* with respect to that of said polarizing filter, and mounted on said support means to receive light transmitted through said polarizing filter along a second axis approximately parallel to said first axis; said sample lens movably positioned to a second position along said second axis whereby determination can be observed through said polarizing analyzer filter if said sample lens has the characteristic of being heat treated and air cooled hardened or chemically hardened; an ultraviolet light source mounted on said support means so as to radiate said sample lens in either said first or said second position to effect a change in observable density if said sample lens has photochromic characteristics.