| 摘要 |
PURPOSE:To detect an object to be detected without being affected by diffused external light, etc., by providing at least >=2 photodetecting elements and subjecting the output values of the respective photodetecting elements to a subtraction process. CONSTITUTION:A detecting part 2 is so constituted that the outputs of photodiodes 41, 42 are inputted by codes to a substrate 55. A photodetecting part 40 is constituted of the photodiodes 41, 42 and an arithmetic circuit 50 of operational amplifiers 51-53 in such detecting part 2. Photodetection signals DS1, DS2 of the polarity values reverse from each other are inputted from the photodiodes 41, 42 of the photodetecting part 40 to the operational amplifier 53 of the arithmetic circuit part 50. The difference between the two signals DS1 and DS2, i.e., a fluorescence emission signal DS5 indicating the fluorescence of glue is inputted to the amplifier 54, from which a detection output KS1 is outputted. The signal levels of the computed signals from the influence of the diffused external light and improving the S/N without weakening the emission intensity of the detected fluorescence by subtracting the signal levels of the arithmetic signals DS3, DS4 from the two photodiodes 41, 42 are subtracted to form the signal DS5 in this photodetecting part 2, by which the influence of the diffused external light is eliminated and the S/N is improved without weakening the emission intensity of the detected fluorescence. |
