Abstract: An object is to provide an optical glass with a near-infrared absorbing function that maintains constant and high transmittance in a visible light range and also has excellent oblique incidence characteristics as well as excellent durability, heat resistance, and weather resistance, and to provide a near-infrared cut filter, a glass element for press molding, an optical element blank, and an optical element including the same. Provided is an optical glass including a glass composition as a base containing at least Yb2O3 and B2O3 as essential components, the optical glass characterized in that a content of Yb2O3 is 5% to 60% by mass, a content of B2O3 is 10% to 50% by mass, and when a thickness of the optical glass is 2.5 mm, average transmittance in a wavelength range of 925 to 955 nm is 0% to 70%, and average transmittance in a wavelength range of 965 to 985 nm is 0% to 50%.

Abstract: Glass surfaces are produced having a highly polished surface by polishing with a glass polishing liquid having a pH approximating the pH of the glass being polished. The method provides highly polished, smooth, highly accurate glass surfaces suitable for use optical filters and solid camera devices and solid image sensors. Phosphate and fluorophosphate glass filters and the like so formed have hair-like surface flaws, if any, of a width of 7 &mgr;m or less.

Abstract: A glass for a near infrared absorption filter, which has spectral characteristics that it efficiently transmits light in a wavelength region of from ultraviolet region to 600 nm and selectively absorbs light in a near infrared region of a wavelength of larger than about 600 nm, a near infrared absorption filter formed of the above glass, and a solid-state image sensing device to which the above filter is applied, the glass comprising, by cationic %, 35 to 54% of P, 20 to 47% of Zn, 0 to 8% of the total, R, of Li, Na, K and Cs which are monovalent metal elements, 0 to 17% of the total, M, of Mg, Ca, Ba, Sr and Pb which are divalent metal elements, the total of R and M being 1 to 22%, 0.1 to 7% of As, 0.2 to 9% of Cu and 0 to 6% of Al.

Abstract: Phosphate or flurorophosphate glass surfaces are polished to smooth, highly accurate surfaces using a glass polishing liquid having a pH approximating the pH of the glass being polished. A highly polished glass surface results suitable for use optical filters and solid camera devices and solid image sensors. Phosphate and fluorophosphate glass filters and the like so formed have hair-like surface flaws, if any, of a width of 7 .mu.m or less.

Abstract: A near infrared absorption filter glass containing______________________________________ P.sub.2 O.sub.5 35.about.50% Li.sub.2 O 0.about.5% Na.sub.2 O 0.about.12% K.sub.2 O 0.about.20% Cs.sub.2 O 0.about.20% R.sub.2 O (in which R is an alkali metal) 1.5.about.20% ZnO 17.about.48% MgO 0.about.7% CaO 0.about.7% SrO 0.about.7% BaO 0.about.12% R'O (in which R' is an alkaline earth metal) 0.about.15% CuO 0.2.about.12% ______________________________________ in which % stands for % by weighthas excellent transmittance characteristics in the ultraviolet region over conventional phosphate-based glass, has glass stability and processability which enable the mass production, and further has sufficient weatherability.