| 摘要 |
758,734. Elongated lamp fittings. BRITISH THOMSON-HOUSTON CO., Ltd. Oct. 19, 1954 [Nov. 24, 1953], No. 32591/53. Classes 75(2) and 75(4). In an electric lantern particularly for street lighting, having reflectors 5, 5<SP>1</SP> arranged on both sides of the vertical axial plane containing the axis of the elongated light source 3 so as to redirect light emanating from the source over predetermined arcs back towards the said plane for emission from the lantern, a refractor device, shown in the form of a plate 7 is arranged to intercept at least some. of the reflected light to modify its direction so as to increase the light intensity in a desired direction or to increase the width of the beam in the desired direction. The refractor plate 7 is formed from twin plates of transparent material each provided on one face with a series of prisms 8 of form appropriate to their required functions, the plates being secured together with their prismatic faces opposing and corresponding prisms in the respective plates aligned in relation to each other and parallel to the axis of the source 3. The top surface 7<SP>1</SP> is opaque. |
