Abstract: For cooling the faceplate of a high-energy cathode ray tube in an in-line television projection system, a cooling cell (5) constructed as a separate entity is interposed between the CRT faceplate (2) and the transmission lens (3) which is arranged in front of and in line with the cathode ray (1). The cooling cell comprises two flexible transparent diaphragms (6 and 7) which are connected at their peripheries to form an enclosure (8) for containing a cooling liquid and which are arranged in contact with the front surface 2a of the CRT faceplate and the rear surface (4) of the lens. The cooling cell has an inlet (11) and an outlet (12) through which circulating liquid enters and leaves the cell.

Abstract: A lens is produced having one aspherical surface which is accurately axially aligned with a spherical or flat surface on the opposite side of the lens. The aspherical surface is produced with a mold. The mold has a molding surface having an accurate negative profile and the desired finish of the required aspherical surface.The mold is on a rotatable jig. By means of adjustment screws the mold is adjusted to correct misalignment of the axis of the molding surface and the axis of rotation of the jig. Misalignment is detected by directing a collimated light beam onto the molding surface so that it is reflected onto a screen. When the mold is rotated, the light beam moves on the screen until the molding surface is properly aligned with the axis of rotation.A preformed glass substrate has one aspherical surface of approximately the desired profile and finish and on its opposite side a spherical or flat surface.

Abstract: A method of manufacturing a multiple mirror reflector for land based telescopes. At least one series of identical segments are mounted on a rigid support to form a large primary reflector with each segment forming a part of the total profile. Each segment includes an accurately profiled reflective metal layer bonded to a concave surface of a substrate by an adhesive layer. The layer is formed on the appropriate substrate surface by transfer replication.

Abstract: A polygonally shaped, multifaceted rotary scanner comprising a plurality of optically flat, reflective surfaces on the facets. The reflective surfaces are integrally bonded to a multifaceted, polygonal base at precise angles to the axis of rotation by a replication technique in which each optically flat reflective surface is produced on the surface of a flat master preform, and the flat master preform is then accurately located in position at the precise angle relative to the base by contact with upper and lower facets of a master multifaceted polygonal fixture. The flat reflective surface is then adhesively bonded to the corresponding facet of the polygonal base (while the polygonal base is arranged concentrically between the upper and lower facets of the fixture) by the application of a small quantity of a liquid adhesive to the surface of the facet of the polygonal base. On hardening, the adhesive bonds the reflective layer of each master preform to the appropriate facet of the polygonal base.

Abstract: A method of making a master replicating tool having a predetermined negative aspherical profile from which aspherical profiled optical elements can be made, comprising machining a blank of a hard, non deformable siliceous material with a cutting tool in a one stage machining operation to produce substantially the predetermined profile, coating the surface so produced with a layer of nickel or nickel based alloy, machining the nickel or nickel based alloy to produce the predetermined profile with the cutting tool and protecting the surface by applying a layer of an inert, scratch-resistant material thereon. Hand figuring the blank after machining is avoided. The scratch-resistant layer is thin and can be between 500 A and 5000 A thick. This layer is applied by vapour deposition and is preferably vacuum deposited vitreous carbon.

Abstract: A method of producing an aspherical optical element involves first forming a glass substrate with at least part of one surface having an irregular surface finish and an aspherical profile having a second order accuracy, which can be obtained by automatic tooling methods, and thereafter forming a polymeric material on such surface so as to form a surface making up differences between the aspherical parts of the substrate and a predetermined, desired aspherical profile, i.e. one of the first order of accuracy which can be obtained only by detailed and skilled hand work.

Abstract: An aspheric element, placed near a principle plane of an wide-angle, wide-aperture image forming system and having in its aspheric function a term proportional to the third power of the distance from the optic axis improves off-axis revolution.

Abstract: An optical element comprising a glass substrate on which a plastics material defining an optical surface is moulded. Shrinkage of the plastics material during curing is compensated for by allowing the glass substrate to deform due to the shrinkage, and optically working flat the outer surface of the glass substrate so that when the element is released from mould this outer surface will restore and take up a curvature which is equal to the amount of curvature lost at the moulded optical surface due to the shrinkage.Fig. 1 is best suited for early publication purposes.