GB458509A - Improvements in or relating to anti-dazzle screens and transparencies - Google Patents

Abstract

458,509. Vehicle antidazzle screens; transparencies; vehicle lamps. COOKE, A. G., 101, Brondesbury Road, Kilburn, London. June 12, 1935, No. 16895. [Class 103 (ii)] [See also Groups X and XI] A transparency or an antidazzle screen adapted to be placed in front of a vehicle lamp or on or adjacent to a vehicle windscreen and which is substantially transparentwhen viewed in one direction and semi-opaque when viewed in a different direction, comprises a composite thick plate of transparent refracting material composed of a plurality of superposed, parallelogram-section, prismatic elements of glass, celluloid, the material known under the Registered Trade Mark " Perspex," or other transparent material, the shorter diagonal of each element being substantially equal and perpendicular to the shorter sides while the adjacent surfaces 3 of the elements are separated by a thin film or sheet 5 of semi-opaque material such as blue or amber-coloured celluloid. The angle between the faces 2, 3 of each element is between 42 and 45‹. The screen may be formed from a pile of slabs of transparent material interleaved with thin sheets of coloured material, by cutting the pile at an angle of 45<0> into slices having a thickness 1À414 times that of each slab. When used in connection with a vehicle windscreen the required effect is obtained by movement of the driver's head or by rotating the antidazzle screen.