Reflectance colorimetry measurement system using scanning spectrometer with array detector

Abstract

A reflectance colorimetry measurement system is constructed using scanning spectrometer with array detector, and the color measurement can be achieved under 45:0 and 0:45 geometry conditions. Typically, there are two types of spectrometer for colorimetry measurement: the scanning spectrometer with single-channel detector requires point-by-point spectral reading, and the measurement is time consuming; array sensor spectrometer (multichannel spectrometer) can completes the measurement in a few milliseconds, but its spectral resolution and range are limited by the array sensor and the optical elements. This colorimetry measurement system is designed for color calibration service, it using a scanning spectrometer with array detector, which divides the board spectral measurement range into sections, and uses the array detector to measure each section respectively, thus achieving the rapid measurement of spectral data with high resolution and wide wavelength range, so as to realized fast color measurement with high precision. The array sensor of the system using a photo diode array (PDA) with 1024 pixel, having a larger dynamic range and better linearity compared to CCD. The grating is rotated with a precision rotation stage, and the rotation angle is calculated basing the parameters of grating and collimator lens, so as to stitch the spectral data of each measurement section., the measurement signal is mutated at the junction point between measurement sections, due to the rotation angle and the shape of grating efficiency curve. The theoretical analysis and experiment shows that the signal mutation at the junction point can be eliminated by comparison measurement of reflectance.