| 摘要 |
<p>The present invention generally relates to an optical system for a wash light and specifically to a variable beam angle system which provides an improved range of beam angles and efficient light output. The present invention includes a light modulating optical element that has a central aperture that can be moved along the optical axis the system. Further the central aperture of the modulating element may be occluded by a diffusing element. The extent of the occlusion can be varied. At a first limit position when the optical system is adjusted so as to provide the minimum beam divergence the light beam will pass through the aperture with no intensity loss. In this configuration the first optical element has practically no effect on the beam. At a second limit position when the optical system is adjusted so as to provide the maximum beam divergence the diffusers cover the central aperture to diffuse the central illumination so as to avoid excessive intensity in the beam centre. The range of beam angles and light modulation can be further improved by means of a variable sized aperature.</p> |
