PHOTIC PAROXYSMAL BRAIN WAVE REACTION PREVENTIVE FILTER

摘要

A filter for preventing children who might have a photic paroxysmal brain wave reaction induced even by a feeble photic stimulation such as by viewing a CRT (TV) from being provoked to have a photic paraoxysmal brain wave reaction and a subsequent photosensitive attack. The filter has a characteristic that the transmittance shown by the attenuation curve drawn toward the long wavelength side in the range over at least 600 nm decreases to 20 % at the range from 610 to 680 nm and a characteristic that the average transmittance over the range from 400 to 700 nm is suppressed below 65-50 %. The characteristics of the filter are realized by coloring glass or resin by adding a coloring component containing Cu ions essentially and at least one kind of ions among from Nd ions, Fe ions, Co ions, and Mn ions, thus producing a filter of absorption type preferable to, e. g. a CRT (TV).