Spectral Sensor Module Using Absorption and Interference Filters

The patent combines multiple filter types (absorption color filters and interference-based filters) with digital image sensors into an integrated spectral sensor module. This merging of components allows the system to achieve high spectral resolution through the complementary filtering mechanisms while maintaining a compact form factor, resolving the contradiction between measurement precision and device complexity.

The patent employs composite filtering structures that integrate absorption type color filters with interference-based filters. This composite approach combines the wavelength-selective properties of absorption filters with the sharp spectral features of interference filters, achieving superior spectral resolution and accuracy while managing the overall device complexity through integrated design.

The patent applies different filter types at different locations in the optical path: absorption color filters are positioned to provide broad wavelength selection, while interference-based filters are strategically placed to provide sharp spectral features at specific wavelength bands. This local differentiation allows the system to achieve high spectral accuracy while minimizing overall light loss by using each filter type where it is most effective.

The patent employs a multi-stage filtering approach where absorption filters provide initial wavelength selection and interference filters provide refined spectral separation. This partial action at each stage achieves cumulative spectral accuracy improvement while the progressive filtering minimizes energy loss compared to using a single complex filter that would need to reject all unwanted wavelengths at once.