Abstract: To provide a novel glass composition having the property of browning substantially improved, while securing an adequate X-ray absorption property and while suppressing devitrification of a panel glass to a practically problem-free level, in preparation for higher voltage and larger current for projection type cathode ray tubes. A panel glass for cathode ray tube, having a glass composition containing substantially no PbO, and more than 10 mass % and at most 15 mass % of ZnO, wherein (MgO (mass %)+ZnO (mass %))/(SrO (mass %)+BaO(mass %)+CaO (mass %))>0.55, and wherein when the sum of Na2O (mol %), K2O (mol %) and Li2O (mol %), as represented by mol percentage, is represented by R2O, 0.15?Na2O (mol %)/R2O?0.25, and 0.45?K2O (mol %)/R2O?0.55, and the linear absorption coefficient of X-ray having a wavelength of 0.06 nm is at least 36.0 cm?1.

Abstract: A method for holding an edge of a molten glass flow, comprising forming a molten glass flow by continuously feeding molten glass on a bath surface of molten metal contained in a vessel, holding an edge of the molten glass flow in a width direction thereof when advancing the molten glass flow to draw the molten glass flow in a glass ribbon having a target thickness, and controlling a flow of the molten metal so that a bath surface level in height of the molten metal in the vicinity of the edge of the molten glass flow is different from that of the molten metal in the vicinity of a central portion of the molten glass flow in the width direction thereof, whereby a force to spread or narrow the molten glass flow in the width direction is compensated so as to hold the edge of the molten glass flow at a predetermined position.