| 摘要 |
<p>An electric light fixture (10) is disclosed which includes a lamp head housing (12), a lamp or bulb (22) within the housing (12) and an elliptical reflector (20) for focusing light from the lamp (22) to a predetermined focal point (24). A transparent lens (40) is positioned across the open end of the housing (12) and an extension ring (30) is removably mounted on that open end of the housing (12) and extends away from the housing (12) and the lens (40). This ring (30) creates an air space (50) beneath the lens (40) within the confines of the ring (30) that traps heat generated from the bulb (22) and reflected to a position within the ring (30) whereby dust particles are deflected away from the lens (40) by convection air flow created as a result of the heat trapped in such space (50).</p> |
