| 摘要 |
1,112,674. Electric incandescent lamps. C. R. FULLER and E. B. MYERS, [trading as FULLER-MYERS]. 17 May, 1965 [19 May, 1964], No. 20850/65. Heading H1F. [Also in Division F4] A lamp such as a vehicle headlamp comprises a trough-shaped reflector having a first portion and a second portion, the cross-sections of the two portions being in the form of different conic sections with a common focus and a source of light being disposed parallel and adjacent to the common focal line of the reflector. The source is either a ribbon filament positioned so that the opposite sides of the filament direct light towards the respective portions of the reflector, or a gas-filled arc discharge capillary tube. In the preferred embodiment the two portions have a common vertex and the line joining the focus and the vertex of each section is horizontal, the upper section being an ellipse and the lower section a parabola so that all the light emitted by the lamp is below a horizontal plane. The reflector may be made of metal or glass having a vapour deposited layer of aluminium protected by a quarter wavelength layer of silicon monoxide. When the source is a ribbon filament it may be disposed in a separate tubular glass bulb or mounted directly in the lamp, an atmosphere of iodine vapour and argon or xenon being provided in each case. The front glass of the lamp may have a vapour deposited coating of magnesium fluoride. |
