| 摘要 |
414,726. Street &c. lamps. GENERAL ELECTRIC CO., Ltd., and DAMANT, E. L. B., Magnet House, Kingsway, London. Feb. 8, 1933, No. 3868. [Classes 75 (ii) and 75 (iv).] In a fitting adapted to redistribute light from a source into a plurality of preferred directions, means are provided for reducing the effective brightness of some part of the source as viewed from one of the said preferred directions relatively to the effective brightness of some part of the source as viewed from another of the said preferred directions. The invention is particularly applicable to street lamps in which the preferred directions are up and down the street. The effective brightness may be reduced by increasing the effective area of the source, as by means of fluted or ribbed glass, ground glass or like diffusing surfaces, or a series of spaced reflecting strips returning light to the source, or it may be reduced by interposing a medium that absorbs light without altering its direction. The difference in effective brightness may be obtained by using a fluted glass or the like on one side only of the source, or by using two or more glasses having flutes of different light-spreading strengths. In the form shown, a vertical linear electric discharge tube 1 is arranged between a pair of prismatic refractors 2, 2<1> having vertical prisms to direct the light up and down the street and slightly towards the opposite side, these refractors being associated with glasses 3, 3<1> having vertical convex ribs. The glass 3 is adapted to face on-coming traffic on the same side of the street and the effective brightness on this side is made less than that on the opposite side by providing the glass 3 with ribs of less radius of curvature than those on glass 3<1>. Reference has been directed by the Comptroller to Specification 408,419. |
