Light filter for improving vision

US5235358A · kind A · utility

Inventors

• Maximillian F. Mutzhas · Munich, DE
• Seymour Zigman · Munich, DE

Key dates

• Filing date: Oct 21, 1991
• Grant date: Aug 10, 1993
• Expiry date: Oct 21, 2011

Classification

• Technology area (CPC G): Physics
• CPC primary: G02C2202/16
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

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.sup.-1, a means transmittance (.tau..sub.2) in a spectral range from 380 to 450 nm of at most 20%, and a means transmittance (.tau..sub.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..sub.2) in the 380 to 450 nm spectral range is at most 10% and the means transmittance (.tau..sub.3) in the 450 to 550 nm spectral range is at least 60%. Further, the light filter has a means transmittance of (.tau..sub.4) in a 550 to 780 nm spectral range of at least 65% and a means transmittance (.tau..sub.1) in a 250 to 380 nm spectral range of at most 10%.