METHOD AND APPARATUS FOR LOCALLY MEASURING REFRACTIVE CHARACTERISTICS OF A LENS IN ONE OR SEVERAL SPECIFIC POINTS OF SAID LENS

摘要

The invention concerns a measuring apparatus comprising: a support (40) designed to receive such a lens, alone or on its frame; on one first side of said support, illuminating means (21) including an optical system for producing a collimated light beam (28) directed towards the lens (L) arranged on said support; and on one side or the other of the support (40), means (23) for detaching light rays of the light beam, capable of separating a localized group of at least three non-coplanar light rays clustered about a measuring axis passing through the measuring point of the lens, into a measuring cylinder having a cross-section substantially smaller than the measured lens; on a second side of the support (40), acquisition means (30) for reading the deflections imparted by the lens to said separated light rays and for delivering a signal representing said deflection; an electronic and computer system (50) programmed to deduce from said deflections the value of the characteristic of the lens (L) at the measuring point. Since the support (40) is fixed relative to the illuminating means (21), the means separating the light rays have an adaptive geometry controlled by the electronic and computer system (50) to modify the position of the measuring axis based on the position of the measuring point.