| 摘要 |
1,163,607. Lamps. KALLE A.G. 21 Dec., 1966 [22 Dec., 1965], No. 57131/66. Heading F4R. [Also in Division G2] An illuminating device for use in photocopying apparatus comprises a light source 20 which emits light through a wide angle and a grating 17 of reflecting elements which allows some light to pass through unreflected but reflects towards the normal path any rays which deviate from the normal by more than a given angle, which lies between 5 degrees and 40 degrees. The grating is made of polished aluminium or of plastics material having a metallized, preferably aluminium surface, and a thin layer of aluminium oxide impregnated with dye may be provided on the aluminium. Alternatively, if strong reflection in the ultraviolet range is desired the plastics may be coated with tantalum. The reflecting surfaces diverge from one another away from the light source at an angle of 5 degrees to 35 degrees, and are formed on the sides of triangular sectioned portions of the grating, the bases of which face the light source and are preferably also reflective. The bases may be formed in two parts set at an angle of between 135 degrees and 179 degrees. The reflecting surfaces may be flat or curved (Figures 1b, 1c, not shown) and in plan view may form a rectangular pattern, as illustrated, or a honeycomb design of equilateral hexagons. In an alternative embodiment (Figs. 2 and 3, not shown) the grating is composed of quadrant sections (9a, 9b) surrounding a single tubular light source (7) and separated by matt black screens (10a, 10b, 10c), the assembly being mounted inside a rotatable glass cylinder (8) and a fan being provided to blow cooling air over the source. In a modification the grating is replaced by a continuous reflecting element of substantially triangular section which is wound around the tube in the form of a spiral. |
