Abstract: A fiber, especially an optical fiber, comprising a lightguide, provided with a protective coating comprising at least one layer of a crosslinked epoxidized-polydiene oligomer, as well as to a process for manufacturing such a fiber. The protective coating may include an intermediate layer of a crosslinked material that adheres to the fiber less strongly than the crosslinked epoxidized-polydiene oligomer.

Abstract: The color video-endoscope (100) comprises in particular:a single light source (10);a bundle of optical fibers (40) for transmitting the light to a field of observation;a periodic filtering device (50) including three filters (53, 54, 55) illuminating the field of observation with three respective primary colors (R, G, B), and a fourth filter zone (56) which is transparent and through which the light also passes;a photosensitive sensor (60) for picking up an image of objects situated in the field of observation;an analog-to-digital converter (91) for digitizing the periodic information from the sensor (60) representative of color images (RGB) and of a black-and-white image (B/W), with the digital information being stored in four respective memories (81 to 84); anda color toning device (85a, 85b) selectively combining the black-and-white image information (B/W) with the color information for the purpose of reconstituting a color image of very good quality.

Abstract: A rigid video-endoscope having an optical system which provide a rotatable image of an object to be observed is shown and described. The optical system is inside a rigid tube. A camera who's axis is in alignment with the optical axis of the optical system picks up the image provided by the optical system. A bundle of optical fibers passing along the tube is connected to a light source for illumination of the object to be observed. Rotation of the image provided by the optical system which adjusts the orientation of the image relative to an observer. The rotating device is disposed inside a handle of the video-endoscope together with the camera and disposed between the camera and the optical system.

Abstract: A quick connector for optical fibers of the type comprising a first and second tubular bodies through which passes an optical fiber, which are aligned axially and joined together by means of a nut which partially envelops the second body and is screwed about the first body. The connector further comprises means for fixing and centering the fiber by clamping, this means being formed more particularly by a rigid sleeve and a deformable sleeve intended to be fitted on the optical fiber and to be housed end to end inside said second body.Furthermore, the connector cooperates with a tool intended to carry out the circular cutting or cleavage of the proximal end of the optical fiber.

Abstract: A method for the production of a preform with a view to obtain an optical fibre with index jump or gradient, consisting in spreading over a substrate, a solution of doped transparent substance, the said substrate being simultaneously driven in rotation about its axis and heated; the solution is spread over successive parts of the substrate, and each part starts being heated when the solution is being spread thereon.The present invention finds an application in the production of silica preforms.

Abstract: Oxadiazoline derivatives of the formula: ##SPC1##Wherein R is alkyl of 1 through 4 carbon atoms, which are useful as intermediates in the synthesis of oxadiazoline derivatives of the formula: ##SPC2##Wherein R is as defined above and R.sub.1 is alkyl of 1 through 4 carbon atoms, possessing useful herbicidal properties, are prepared by a process which comprises reducing the nitro group in a 5-alkyl-3-(2-nitro-4-chlorophenyl)-1,3,4-oxadiazolin of the formula: ##SPC3##Wherein R is as defined above to a hydroxylamino group, subjecting the resulting 5-alkyl-3-(2-hydroxylamino-4-chlorophenyl)-1,3,4-oxadiazolin-2-one to the Bamberger rearrangement, and converting the amine group in the resulting 5-alkyl-3-(2-amino-4-chloro-5-hydroxyphenyl)-1,3,4-oxadiazolin-2-one to a chlorine atom. The 5-alkyl-3-(2-hydroxylamino-4-chlorophenyl)-1,3,4-oxadiazolin-2-one intermediates are compounds.