Test of a novel microlens grating based miniature spectrometers array for chromatic confocal technology

Multifocal chromatic confocal techniques have important applications in 3D measurement. A chromatic confocal system consists of a dispersive objective, a light source, a fiber coupler, and a spectrometer. An array of spectrometers is required when applying a chromatic confocal sensor for multifocal scanning. A novel microspectrometer array utilizing a single hybrid optical device with microlens array and grating surface on its two sides is developed, which differs from the state-of-the-art micro or miniature spectrometers array usually with a combination use of a microlens arrays a grating. For investigation of feasibility of these microlens array-grating based microspectrometer in multifocal chromatic confocal scanning, we built a chromatic confocal system and test bench, developed an evaluation methodology. Testing results demonstrated that the repeatability of detection is in 0.5 pixel. which proves that the microlens grating spectrometer is reliable.