| 摘要 |
PCT No. PCT/EP89/01329 Sec. 371 Date Oct. 21, 1991 Sec. 102(e) Date Oct. 21, 1991 PCT Filed Nov. 7, 1989 PCT Pub. No. WO90/05321 PCT Pub. Date May 17, 1990.A light filter for filtering light for a human eye with the filter being formed of a plastic material in combination with the filtering material. The filtering material is added so as to provide the filter with spectral transmittance characteristics which include a cut-off location ( lambda H) of 450 nm to 550 nm, a steepness (S) for the transmittance curve at the cut-off location of at least 1%.nm-1, a means transmittance ( tau 2) in a spectral range from 380 to 450 nm of at most 20%, and a means transmittance ( tau 3) in a spectral range from 450 to 550 nm of at least 40%. The filtering material preferably includes an organic dye dissolved in the plastic or an organic pigment finely distributed in the plastic material. In addition, the mean transmittance ( tau 2) in the 380 to 450 nm spectral range is at most 10% and the means transmittance ( tau 3) in the 450 to 550 nm spectral range is at least 60%. Further, the light filter has a means transmittance of ( tau 4) in a 550 to 780 nm spectral range of at least 65% and a means transmittance ( tau 1) in a 250 to 380 nm spectral range of at most 10%.
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