A Collimated LED Light Module for Absorbance Detection

摘要

In the bio absorbance detection systems, sensitivity of detection depends on collimation length of light module. Although the conventional LEDs have the advantages of low cost and compact, their light is diverged with divergence angle larger than 10 degree. Therefore, conventional LEDs are not suitable for bio-chip absorbance detection. By exploiting the concept of fiber collimator, this project proposes a design to realize a collimated light module. The advantages of low cost, miniaturized, and multi-channel capability are then achieved. The divergence angle of this collimator is about 1.2 degree within 1.5 cm optical path length. The power variation of this module is under 1% within an hour. The absorbance experiment to measure sodium pyruvate range from 0 to 82μM using fabricated light module was conducted, where sensitivity of 7.7×10{sup}3 / M and linearity of 0.9995 R{sup}2 is obtained.