| 摘要 |
<p>To provide an increase horizontal spread of light compared with a paraboloidal reflector, the lamp reflector comprises a dished body (10) having an internal reflective surface defined at least partly by a series of troughs (15) whose surfaces are generated by movement of a parabola so that the tangent at the apex thereof moves parallel to itself along a polygonal line whose sides are tangents to a parabola which has the same focal length as that of the first-mentioned parabola and which is perpendicular to the latter. In an alternative embodiment, only one such trough is provided between a pair of paraboloidal reflective portions each of which has its focus coincident with the second-mentioned parabola.</p> |
