Abstract: A glass filter for contrast enhancement in a color CRT display devices comprises100 parts by weight of a base glass comprising, in % by weight3 to 70% SiO.sub.2,0 to 40% B.sub.2 O.sub.3,0 to 23% Al.sub.2 O.sub.3,0 to 23% R.sub.2 O (R.sub.2 O being at least one selected from the group consisting of Li.sub.2 O, Na.sub.2 O and K.sub.2 O),2 to 35% RO (RO being at least one selected from the group consisting of MgO, CaO, SrO, BaO, ZnO and PbO),0 to 10% TiO.sub.2,0 to 10% ZrO.sub.2,0 to 35% La.sub.2 O.sub.3 and5 to 40% Nd.sub.2 O.sub.3,at least two coloring components selected form the group consisting of 6 parts by weight or less CeO.sub.2, 1.0 parts by weight or less CuO, 3.5 parts by weight or less MnO.sub.2, 0.15 parts by weight or less CoO, 3.0 parts by weight or less Fe.sub.2 O.sub.3, 1.5 parts by weight or less NiO and 5.0 parts by weight or less Pr.sub.6 O.sub.11, andat least one coloring component selected form the group consisting of CeO, CuO, MnO.sub.2 and CoO.

Abstract: A method for irradiating a chemically machinable light-sensitive glass plate with a parallel bundle of ultraviolet rays so as to form tapered holes or slits in the glass plate. A mask having a desired shaped opening is mounted on the light-sensitive glass plate and the plate is disposed so that its surface forms a predetermined angle with a plane which is perpendicular to the parallel bundle of ultraviolet rays. The glass plate is then rotated about a central vertical axis thereof.

Abstract: A method for irradiating a chemically machinable light-sensitive glass plate with a parallel bundle of ultraviolet rays so as to form a tappered polygonal hole in the glass plate. A mask having a regular polygonal opening having n vertexes is mounted on a machinable light-sensitive glass plate and a light source capable of generating a parallel bundle of ultraviolet is disposed so that one of the vertexes of the polygonal opening is positioned at the longest point from the center of the light source. The glass plate is then irradiated. Thereafter, the light source is rotated about a center axis of the opening by an angle equal to 360.degree./n and the glass plate is re-irradiated. This procedure is conducted so that the glass plate is irradiated n times.

Abstract: A glass for use as an optical glass having an anti-blurring property, water resistance and hardness and decreased liquidus temperature, said glass consisting essentially of, in mol. %, 47 to 65% P.sub.2 O.sub.5, 0.5 to 12% SiO.sub.2, 0.5 to 10% B.sub.2 O.sub.3, 6 to 15% SiO.sub.2 +B.sub.2 O.sub.3, 0 to 30% alkali metal oxide, 5 to 35% alkaline earth metal oxide, 20 to 45% alkali metal oxide+alkaline earth metal oxide, 0 to 5% Al.sub.2 O.sub.3, 0 to 10% ZnO, and no PbO. Oxides of Ce, Nd and Er may also be present.

Abstract: A near infrared absorption filter for color television cameras, comprising(a) a base glass comprising, in % by weight based on the weight of the base glass, 50-78% P.sub.2 O.sub.5, 10-50% BaO, 0-7% Al.sub.2 O.sub.3, 0-6% B.sub.2 O.sub.3, 0-5% SiO.sub.2, 0-8% Li.sub.2 O, 0-15% Na.sub.2 O, 0-18% K.sub.2 O, 0-5% MgO, 0-10% CaO, 0-15% SrO, 0-10% ZnO, and 0-10% PbO, and(b) about 0.5 to about 2.5% by weight of CuO based on the weight of the base glass.

Abstract: A green contrast enhancement filter for CRT display devices which is prepared by adding about 0.1 to 1.5 part by weight of Cr.sub.2 O.sub.3, about 0 to 0.5 part by weight of CuO and about 0 to 0.2 part by weight of NiO to 100 parts by weight of a base glass comprising about 4 to 70% by weight of SiO.sub.2, about 15 to 30% by weight of Nd.sub.2 O.sub.3, about 0 to 25% by weight of one or more alkali metal oxides (R.sub.2 O) and about 0 to 46% by weight of one or more divalent metal oxides (RO) such as MgO, CaO, SrO, BaO, ZnO and PbO, wherein the sum R.sub.2 O+RO is about 10 to 50% by weight, about 0 to 25% by weight B.sub.2 O.sub.3, about 10% by weight or less Al.sub.2 O.sub.3 and about 0 to 10% by weight each of TiO.sub.2, ZrO.sub.2, La.sub.2 O.sub.3, Nb.sub.2 O.sub.5 and Ta.sub.2 O.sub.5.

Abstract: A green colored filter glass comprising(a) 100 parts by weight of a base glass consisting of, by weight, 40 to 85% P.sub.2 O.sub.5, 2 to 10% Al.sub.2 O.sub.3, 0 to 53% BaO, 0 to 15% Li.sub.2 O, 3 to 53% BaO+ Li.sub.2 O, 0 to 15% NaO and/or K.sub.2 O, 0 to 10% MgO, CaO, ZnO and/or PbO, 0 to 20% SrO and 0 to 5% B.sub.2 O.sub.3, ZrO.sub.2, TiO.sub.2 and/or La.sub.2 O.sub.3 ;(b) 0.01 to 3.0 parts by weight of NiO; and(c) 0.02 to 3.0 parts by weight of CuO.

Abstract: A yellow colored filter glass comprising(a) 100 parts by weight of a base glass consisting of, by weight, 65 to 85% of P.sub.2 O.sub.5 ; 3 to 10% of Al.sub.2 O.sub.3 ; 0 to 18% of MgO, 0 to 25% of CaO, 0 to 30% of ZnO, with the total proportion of MgO + CaO + ZnO being 10 to 30%; 0 to 15% of SrO and/or BaO; 0 to 10% of PbO; 0 to 10% of at least one of Li.sub.2 O, Na.sub.2 O and K.sub.2 O; and 0 to 5% of B.sub.2 O.sub.3, ZrO.sub.2, TiO.sub.2 or La.sub.2 O.sub.3 ;(b) 0.01 to 1.0 part by weight of NiO; and(c) 0 to 2.0 parts by weight of CuO.

Abstract: This invention provides an anomalous dispersion glass exhibiting an .eta. d value of 1.54-1.71 and an.nu. d value of 55-30, and the anomaly of a partially dispersing property in the long wave length region. The anomalous dispersion glass contains B.sub.2 O.sub.3 45-70 mol.%; Pb0 5-30 mol.%; Na.sub.2 O 1-15 mol.%; SiO.sub.2 0-10 mol.%; Al.sub.2 O.sub.3 5-25 mol.%; one or more of CaO, BaO, MgO and CdO 0-16 mol.%, and one of TiO.sub.2, ZrO.sub.2, Sb.sub.2 O.sub.3, Wo.sub.3 and Tl.sub.2 O 0-3 mol.%. Fluorine may be present in an amount such that the F/O ion ratio in the resulting glass lies in the range of 0-0.35.

Abstract: A reversible light sensitive glass comprising 100 parts of a base glass, 0.15 to 1.0 parts of Ag and an amount of halogen corresponding to or more than to the chemical equivalence of Ag, in which the base glass consists of, by weight %, SiO.sub.2 48 to 62, Al.sub.2 O.sub.3 7 to 15, B.sub.2 O.sub.3 17 to 26, R.sub.2 O (where R represents Na, Li or K) 6 to 16, BaO 0.5 to 5, (BaO/R.sub.2 O 0.05 to 0.40), TiO.sub.2 0 to 10, ZrO.sub.2 0 to 10, Nb.sub.2 O.sub.5 0 to 5, TiO.sub.2 +ZrO.sub.2 +Nb.sub.2 O.sub.5 0.5 to 15, AS.sub.2 O.sub.3 0 to 2.0, and Sb.sub.2 O.sub.3 0 to 2.0 (AS.sub.2 O.sub.3 +Sb.sub.2 O.sub.3 <2.0).

Abstract: A reversible light-sensitive glass comprising 100 parts of a base glass composition consisting, in weight percent, of 48 to 62% SiO.sub.2, 15 to 22% B.sub.2 O.sub.3, 0 to 7% Al.sub.2 O.sub.3, 0 to 10% ZrO.sub.2, 6<Al.sub.2 O.sub.3 + ZrO.sub.2 <12%, 6 to 16% R.sub.2 O where R represents Li, Na or K, 0.5 to 7% BaO, BaO/R.sub.2 O 0.035 to 0.65, 0 to 2% TiO.sub.2, and 0.002 to 0.03% CuO, and as light-sensitive components, 0.15 to 1.0 part of Ag and more than the chemical Ag equivalent of halogens selected from the group consisting of Cl, Br and I.

Abstract: A reversible light-sensitive glass, e.g., for eyeglasses, comprising 100 parts of a base glass composition consisting, in weight percent, of 48 to 62% SiO.sub.2, 15 to 22% B.sub.2 O.sub.3, 0 to 11% Al.sub.2 O.sub.3, 0 to 10% ZrO.sub.2, 6<Al.sub.2 O.sub.3 + ZrO.sub.2 <13%, 6 to 16% R.sub.2 O where R represents Li, Na or K, 0.5 to 7% BaO, BaO/R.sub.2 O 0.035 to 0.65, 0 to 2% TiO.sub.2, 0 to 2.5%Nd.sub.2 O.sub.3, 0 to 2.5% Ho.sub.2 O.sub.3, 0 to 2.5% Er.sub.2 O.sub.3, 0.2<Nd.sub.2 O.sub.3 + Ho.sub.2 O.sub.3 + Er.sub.2 O.sub.3 <2.5% and 0.002 to 0.03%CuO, and as light-sensitive components 0.15 to 1.0 part of Ag and more than the Ag chemical equivalent of halogens selected from the group consisting of Cl, Br and I.