Patent ID: 9000399
Filing Date: 2015-04-07
Classification: G01J,G01N

Abstract:
1. A fluorescence detection optical system comprising: a light source unit which emits excitation light; an objective lens which focuses the excitation light on a microfluidic device; a fluorescence detector which detects fluorescence which is generated by the microfluidic device while a sample in the microfluidic device is excited by the excitation light; an automatic focusing unit which detects the excitation light which is reflected off the microfluidic device, calculates a focusing error of the excitation light reflected off the microfluidic device, and adjusts a focusing position of the objective lens with respect to the microfluidic device; and a light transferring unit which transfers the excitation light emitted from the light source unit to the microfluidic device, transfers the excitation light reflected off the microfluidic device to the automatic focusing unit, and transfers the fluorescence generated by the microfluidic device to the fluorescence detector, wherein the automatic focusing unit comprises: a divided-type photodetector which is divided into a plurality of photodetecting segments; a focusing lens which focuses the excitation light reflected off the microfluidic device; an actuator which adjusts the focusing position of the objective lens; and a focusing control unit which calculates the focusing error from an output of the divided-type photodetector, and controls an operation of the actuator, wherein the automatic focusing unit further comprises a knife edge which is between the focusing lens and the divided-type photodetector, and blocks out-of-focus light, and wherein the divided-type photodetector is a dual-type photodetector comprising two photodetecting segments.