| 摘要 |
To efficiently utilize a halogen incandescent lamp in a flashlight, while providing for essentially uniform illumination of respective spot and flood fields, the halogen incandescent lamp (11) is located within an elliptical reflector portion (12), with the filament of the lamp at one of the focal points of the ellipse. A part spherical reflector portion (13) is joined to the elliptical portion (12). At or close to the second focal point of the ellipse, a diaphragm (14) is located, which diaphragm is imaged by a condenser lens (16). The change between spot and flood illumination is obtained by varying the diaphragm opening, for example by a variable diaphragm size opening, or shifting the diaphragm towards and away from the first focal point. |
