U.S. Philips Corporation

Jan G Peelen

Hermanus N Tuin

Wilhelmus C Meerman

Andreas N Van Geelen

Marius A Klop

Andreas J Piers

Hendrik Venhuizen

Gerrit J Koel

Rene A Pluijms

Johannes Feenstra

Pieter Van Der Ree

The invention comprises a novel type of glass for a cone (3) of a display tube envelope (1), said glass being manufactured by recycling screen glass and cone glass of display tube envelopes. A mixture of screen and cone glasses is supplemented with other glass-forming components to form a novel glass composition which can be used in cone glass applications. The glass is characterized by a relatively high BaO and SrO content. The glass has an x-ray absorption .mu. of at least 65 cm.sup.-1 at 0.6 .ANG..

Glass for a cone of a display tube, display tube envelope comprising a

In the P.C.V.D. process, in principal the quartz tube need not be rotated during the deposition of the glass layers. However, it has been found in practice that an improvement in the quality of the glass fibers can be obtained if the quartz tube is rotated regularly over an angle of 360.degree./n. n is preferably equal to an integer from 2 to 12.

Method of and device for manufacturing optical fibers

While collapsing the central duct in hollow glass optical fiber preforms, an etchant consisting of a mixture of oxygen and a fluorocarbon compound from the group C.sub.2 F.sub.6, C.sub.3 F.sub.8 and N-C.sub.4 F.sub.10 is passed through the duct. In particular, the etchant is passed through the duct only when the duct's diameter is 1 mm or smaller. The resulting solid preforms and optical fibers drawn therefrom do not have a central dip in the refractive index profile.

Method of manufacturing an optical fiber preform

In the P.C.V.D. process in principal the quartz tube need not be rotated during the deposition of the glass layers. However it has been found in practice that an improvement in the quality of the glass fibers can be obtained if the quartz tube is rotated regularly over an angle of 360.degree./n. n is preferably equal to an integer from 2 to 12.

Device for manufacturing optical fiber preforms

Method of and apparatus for manufacturing optical fibers in which a preform is heated in a furnace which is provided with a graphite heating element and a fiber is drawn from the heated preform. The fiber is subsequently cooled, provided with a coating, and, after drying of the coating, the fiber is wound onto a reel. For applying a coating to the fiber, the fiber is passed through a nozzle which has a polygonal nozzle opening.

Coating apparatus for manufacturing optical fibers

Method of and apparatus for manufacturing optical fibers in which a preform is heated in a furnace which is provided with a graphite heating element and a fiber is drawn from the heated preform. The fiber is subsequently cooled, provided with a coating, and, after drying of the coating, the fiber is wound onto a reel. During drawing of the fiber, the preform and fiber are flushed with a gas. According to the invention the gas with which the fiber is flushed is passed along a condensation element.

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Eindhoven, Netherlands

Jan G Peelen