United States Patent 19 11 3,904.425 Young Et Al
United States Patent 19 11 3,904.425 Young et al. (45) Sept. 9, 1975 54) ABSORPTIVE GLASS Primary Examiner-Harvey E. Behrend 75 Inventors: Robert W. Young, Woodstock, Attorney, Agent, or Firm-William C. Nealon; H. R. Conn.; Robert E. Graf, Southbridge, Berkenstock, Jr. Mass. W EXEMPLARY CLAIM 73) Assignee: American Optical Corporation, 1. A glass material having a calculated oxide composi Southbridge, Mass. tion comprising 22 Filed: June 12, 1964 21 Appl. No.: 374,811 Percent by Weight Silicon Dioxidc (SiO) 5.9 Sodium Oxide (NaO) 6.5 (52) U.S. Cl...................................... 106/52; 106/50 Potassium Oxide (KO) 6.8 (51 l Int. Cl........................................... CO3C 13/00 Calcium Oxide (CaO) 6.5 58) Field of Search................................. 106/50, 52 Antimony Trioxide (SbO) 0.4 Aluminum Oxide (AO) 4. Zinc Oxide (ZnO) 2.2 56) References Cited Titanium Dioxidc (TiO) 0.4 Manganese Dioxide (MnO) 23.4 UNITED STATES PATENTS Chromium Oxide (CrO) O.S 2,676,09 4/1954 Barnes ct al.......................... 106752 Tct O).() 2,776,900 l/1957 Duncan et al........................ 106/52 2,898,219 8/1959 Duncan ct al........................ 106/52 2,902,377 9, 1959 Duncan............ ... 106/52 a 100 micron thickness of said glass material having 3,146,2O 8/1964 Upton et al.... ... 106/52 an optical density greater than 0.25 at least for light 3,20386 8/1965 Bull et al.............................. 1 O6/52 from 0.4 to 0.6 microns wavelength. FOREIGN PATENTS OR APPLICATIONS 6 4,357 21 1961 Canada................................. 106/52 6 Claims, No Drawings 3,904,425 2 ABSORPTIVE GLASS als should have optical densities at least as high as 0.25 The field of this invention is that of glass composi in sample thickness as small as 100 microns at least for tions and the invention relates more particularly to light of wavelengths between 0.4 and 0.6 microns.
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