Patent ID: 6284119
Filing Date: 2001-09-04
Classification: G01N

Abstract:
In a DNA base sequencer comprising a gel electrophoretic means having tracks for electrophoresing fluorophore-labelled DNA fragments, a laser diode as a light source for illuminating said tracks with exciting laser light and a CCD sensor for detecting the fluorescence emitted from the illuminated DNA fragments, the improvement wherein said laser diode has a control unit comprising a Peltier device for controlling the temperature of the laser diode, a Peltier device temperature setting generating means having a processor and a memory, and a temperature control circuit that generates a drive current to the Peltier device for controlling its temperature, and wherein said CCD sensor receives part of the exciting light from the laser diode as stray light and detects its wavelength and said Peltier device temperature setting generating means is such that, in accordance with the wavelength of stray light as detected periodically with said CCD sensor according to the program stored in said memory, calculates a corrective value that adjusts the detected wavelength of stray light to the desired wavelength of exciting light that corresponds to the desired temperature setting and an appropriate temperature setting signal is generated on the basis of said corrective value and said desired temperature setting and sent to the Peltier device temperature control circuit.