POLARIZING GLASS HAVING HIGH EXTINCTION RATIO

• Main Authors: IKEDA TAKURO, MAEDA KOZO, MATSUMOTO HITOMI, YANO NOBORU
• Format: Patent
• Language: English
• Published: 08.07.2010
• Subjects: CHEMICAL COMPOSITION OF GLASSES, GLAZES, OR VITREOUSENAMELS; CHEMISTRY; GLASS; JOINING GLASS TO GLASS OR OTHER MATERIALS; METALLURGY; MINERAL OR SLAG WOOL; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS,MINERALS OR SLAGS; SURFACE TREATMENT OF GLASS

PROBLEM TO BE SOLVED: To provide an improved method for producing a polarizing glass exhibiting a high extinction ratio, by facilitating the particle diameter control of silver halide particles in a matrix glass having high Ag concentration, and the polarizing glass produced by the improved method. SOLUTION: There is disclosed the polarizing glass containing dispersed, aligned and shape-anisotropic metallic silver particles at least in the surface layer, wherein the content of TiO2is 1.7 wt.% or below and the content of Ag is 0.42 wt.% or above, the loss in 633 nm is ≤0.6 dB, the extinction ratio is ≥35 dB, and that satisfy the relationships: the Ag/(Cl + Br) molar ratio is 0.2 to 1.0, the Cl/(Cl+Br+F) molar ratio is 0.5 to 0.95, and the Br/(Cl+Br+F) molar ratio is 0.05 to 0.4 and Ag×(Br-F)≤0.1 by wt.%. The composition of the polarizing glass contains 40-63 wt.% SiO2, 15-26 wt.% B2O3, ≤15 wt.% Al2O3, ≤12 wt.% ZrO2, 4-16 wt.% R12O (where R1expresses Li, Na, K and Cs and Li2O: 0-5 wt.%, Na2O: 0-9 wt.%, K2O: 0-12 wt.% and Cs2O:0-6 wt.%) and 0-6 wt.% ZnO. The method of producing the polarizing glass includes a step of stretching glass containing dispersed AgClxBr1-xand a step of reducing under a reduction atmosphere. COPYRIGHT: (C)2010,JPO&INPIT