Rca Inc.

Chih C Wang

Ronald F Bates

Thomas Clifford Lausman

Lincoln Ekstrom

Henry Wielicki

Harry Louis Pinch

Thomas E Smith

An improved process for the batch distillation or purification by stripping of a bis(hydroxyalkyl)disiloxane, which purified product is useful as a video disc lubricant additive or dopant. In accordance with the process, the feedstock of bis(hydroxyalkyl)disiloxane is subjected to a vacuum evaporation of the light volatiles by gradually reducing the pressure to about 2.times.10.sup.-1 Torr. After the low boiling materials have been distilled off, the temperature is gradually increased and the pressure gradually reduced (final temperature of about 135.degree. C. and final pressure of about 4.times.10.sup.-2 Torr) so as to produce a distill and having a viscosity of about 210.+-.30 centipoise at 25.degree. C.

Purification of video disc lubricant additives

High density information discs comprising conductive carbon loaded polyvinylchloride discs are lubricated with a fractionated methyl alkyl siloxane lubricant which contains an alkylene oxide silicone copolymer additive.

High density information disc

Bis(hydroxyalkyl)disiloxane lubricants of the formula ##STR1## wherein R.sub.1 and R.sub.3 are methyl or ethyl and R.sub.2 and R.sub.4 are linear alkyl groups of up to 20 carbon atoms. These compounds are useful as additives to methyl alkyl siloxane lubricants for conductive high density information discs. Discs lubricated with the lubricant mixture exhibit improved stability to environments of high temperature and high relative humidity.

Bis(hydroxylkyl)disiloxanes and lubricant compositions thereof

An improved information storage and playback system comprising a playback stylus and a disc record. The information is recorded in the surface of the disc record and there is relative motion between the disc and the playback stylus during recovery of the recorded information. The stylus is fabricated out of a dielectric support material and contacts the record disc surface during the recovery of the information. The improvement comprises employing a playback stylus whose dielectric support material is single crystal magnesium aluminate spinel. The spinel composition comprises a ratio of MgO to Al.sub.2 O.sub.3 of from about 1:1 to about 1:2.5.

Spinel video disc playback stylus

Bis(hydroxyalkyl)disiloxanes and lubricant compositions thereof

Molecular distillation of methyl alkyl siloxanes of the formula ##STR1## wherein R.sub.1 and R.sub.2 are alkyl groups of 4-20 carbon atoms and m and p are integers to produce a distillate having a molecular weight fraction wherein the sum of m and p is about 4, produces an improved lubricant for the video disc, a lubricant that is stable to long term storage and to wide variations in temperature and relative humidity.

Video disc lubricants

In a method for the glow discharge deposition of an amorphous, continuous layer from an organosilane and oxygen where the deposition is interrupted, wherein a glow discharge in oxygen is employed prior to resumption of glow discharge layer deposition.

Method of depositing an abrasive layer

Siloxanes of the formula ##STR1## wherein R.sub.3 and R.sub.3 ' independently at each occurrence are long chain alkyl groups and m is an integer of 0 or 1, can be employed as lubricants for video discs. The lubricants are stable to long term storage and to wide variations in temperature and humidity.

The method comprises the steps of providing a camera tube having an evacuated envelope, a photoconductive layer primarily of lead monoxide, an activated getter and an unactivated getter within the envelope. After a period of operation or storage the tube exhibits a deterioration in spectral photosensitivity of the layer. The characteristic ratio of blue light photosensitivity is measured and when the ratio is less than about 80% the unactivated getter is activated to regenerate the tube.

Method of regenerating a lead monoxide target layer of a camera tube

A photosensitive layer comprising primarily lead monoxide is deposited on a signal electrode of a vidicon camera tube target. The deposition is carried out in an atmosphere containing oxygen and deuterium oxide. The vidicon target formed exhibits improved transient response leg properties and hole transport characteristics.

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Hightstown, NJ, United States of America

Chih C Wang