| 摘要 |
An optical filter which can be used in a lamp has low attenuation in a selected frequency range and comprises material which absorbs light outside the selected frequency range and fluorescently emits light in the selected frequency range. Hence the fluorescent omission supplements brightness of light from the filter. The filter can absorb infra red frequencies 3 so as to emit light (such as the yellow light in the figures) 2. The filter may consist of a polymer material doped with a fluorescent dye. |
