Multispectral dielectric microfilter arrays for local resolving color sensors

Dielectric microfilters are designed and developed providing different filter functions on 3-in. substrates. Combining several coating procedures, microlithographic techniques, and dry-etching processes, spectral properties of basic filters are modified within patterns with feature sizes down to 5 mu m, resulting in large-area filter patterns (>5 cm2) with multiple spectral characteristics and vertical edge profiles. By applying these techniques within a three-step-iterative procedure red, green, and blue filters (RGB) are arranged edge to edge on one substrate to form a multispectral dielectric microfilter array for use as a key component in a local resolving color sensor. These microfilters are arranged in an array of 19 identical hexagons consisting of three rhombi each. The number of these arrays amounts to 81 on a single 3-in. substrate. A modular setup of a compact local resolving color sensor is presented, consisting of Si-p-i-n photoelectric cells, dielectric microfilter arrays , an imaging lens, and a final glass cover plate with an IR-blocking filter.