GB328017A - Apparatus for use as anti dazzle and fog-penetrating device for use in conjunction with motor car headlamps - Google Patents

Abstract

328,017. Smith, F. H. Jan. M, 1929. Lantern screens. - For anti-dazzle and fog-penetrat. ing purposes a part or the whole of the light projected by a vehicle lamp is adapted to traverse one or more screens each of which contains an electrolytic solution capable of assuming or deepening in an amber, orange, or other colour when an electric current is passed through it and of re-assuming its original clear or slightly tinted state when the currrent is switched off. The screens may contain a solution of potassium iodide and sodium hydroxide, with or without a non-freezing agent such as alcohol or a solution of common salt, lithium chloride, or brine. 'The electrodes may be made of platinum, silver, german silver, tungsten, magnesium, or any other chemical-resisting and non-oxidizable metal or alloy ; they may enter the containers at two or more points, or they may form parts of the containers. The connections to the electrodes may be reversible, or the containers may be turned round to change the polarity of the electrodes. A lesser and higher voltage may be applied to a single container for anti-dazzle and fog-penetrating purposes respectively, or two screens may be employed, the one containing the more concentrated solution being used only when a fog-penetrating light is required. The current for producing an anti-dazzle colour is preferably switched on automatically with the lamp. The screens may be arranged immediately in front of or behind the front glass or between the light source and the reflector. In the form shown in Fig. 1, the solution is contained in a flat pocket 3 formed by two clear glass or like discs 1 and an annular glass or metal spacing washer 2, whilst Fig. 2 shows the bulb b surrounded by two annular containers 4 having cambered peripheries 5. The containers 4 are provided with vent, filling, and emptying nipples 6, preferably fitted with valves or caps, and the electrodes are introduced through stems 7 carried by a cap 9 having contact pins adapted to engage in a socket 9d on the lamp. The containers 4 may be replaced by a single hollow ring or by a close helix of glass tubing, and a flat bulb container may replace the screen shown in Fig. 1 or be arranged horizontally over the top of the bulb b. Such a flat bulb container could also be provided with clips or rubber suckers for mounting it on the front of the lamp. Alternatively a flat bulb container 11, Fig. 6, and a lower coaxial annular container 12 may be supported above the bulb b by means of stems 13. A circular or other container 14, Fig. 7, is provided with uper connecting tubes 17 to provide an anti-dazzle light and with lower passages 18 to provide a fog-penetrating light. The passages 18 may be replaced by connecting tubes, and the connecting tubes may be close together at the top or throughout the depth of the screen, or they may be arranged vertically or otherwise.