| 摘要 |
<p>The present invention relates to a multi color LED based light source, at least comprising several light emitting elements (1, 2, 3) emitting light beams (5, 6, 7) of different colors, a beam combining optics arranged for combining said light beams (5,6,7) to a combined light beam (8), and at least two light sensors (11, 12, 13) arranged at separate locations to measure fractions of light emitted by said light emitting elements (1, 2, 3). The beam combining optics comprises a first wavelength selective element (9) transmitting light of a first (1) of said light emitting elements (1,2,3) in a first wavelength region and reflecting light of a second (2) of said light emitting elements (1,2,3) in a second wavelength region. A first (11) of said sensors (11,12,13) is arranged to measure light of said first light emitting element (1) reflected at said first wavelength selective element (9) and/or to measure light of said second light emitting element (2) transmitted through said first wavelength selective element (9). With the proposed multi color light source cheap light sensors can be used to reliably control the spectral output of the light source.</p> |
