| 摘要 |
<p>Light filter apparatus for receiving a light beam (25) having wavelengths in a selected band and for dispersing the light into a plurality of rays (30), with each ray having a different wavelength for which the intensity peaks. The peak wavelength varies approximately continuously with displacement of spatial position in a chosen direction along the filter's light-receiving plane. In one embodiment, the filter is a modified etalon structure having at least two reflecting surfaces whose separation distance is not constant but increases or decreases monotonically with distance in a chosen direction in a light-receiving plane of the etalon. Each of these two reflecting surfaces (26,27) may be planar or non-planar but continuous, or may have a step or staircase configuration. This structure may operate using transmitted light or reflected light. In a second embodiment, an edge filter combination is used to produce a narrow band of transmitted or reflected light having a variable central wavelength that varies with position along the chosen direction. In a third embodiment, a multi-layer thin film structure is used to provide a narrow band of transmitted or reflected light having a variable central wavelength. The filter may be combined with a one-dimensional or two-dimensional array of photosensor elements, which array may be linear, circular or generally curvilinear, one such element receiving a group of adjacent light rays of similar peak wavelength, to provide a plurality of different wavelength readings on an incident light beam for spectrophotometry or colorimetry analysis. <IMAGE></p> |
