Reverse clipping means null for the optical conservation filter and the optical conservation filter which have the filter element which can control the permeability of the light which relates

摘要

PURPOSE: To intercept interfering light and to improve the detective precision of light sensitive sensors. ;CONSTITUTION: In a light protection filter 3 particularly used for welding technique, by a shielding means 10 fitted or assembled with light sensitive sensors 5 and 6 cooperating with a transmissibility controller, only light emitted from an original operating process (such as welding) is allowed to change the transmissibility of the light protection filter 3, and the influence, e.g. of the illumination of work section on the light protection filter is prevented.;COPYRIGHT: (C)1993,JPO