DIFFERENTIAL TYPE BISECTED PHOTODIODE AND CURVED PRISM TYPE LIQUID REFRACTOMETER USING SAME

摘要

PURPOSE:To enable exact detection of the position of a terminator by forming a set of photodetecting surfaces which are varied in photodetecting area on one chip to constitute a differential type bisected photodiode. CONSTITUTION:The differential type bisected photodiode 10 is formed with a set of the photodetecting surfaces 11, 12 having the different photodetecting surfaces in parallel with the respective terminators to be detected on one ship. A dividing line 13 is formed between the photodetecting surfaces 11 and 12. The photodetecting surface 11 constitutes a zone A and the photodetecting surface 12 constitutes a zone B, respectively. Electrodes 11a, 12a, etc., connected to the photodetecting surfaces 11, 12 are provided to the peripheral edge of the diode 10. Measurement is made by using the photodetecting surfaces 11, 12 of the diode 10 if; for example, the terminator serving as a reference for certain measurement is a-a' concerning said measurement. The output currents from the electrodes 11a, 12a on the photodetecting surfaces 11, 12 of the diode 10 are measured at this time. The calibrated position of the terminator is determined in accordance with the ratio of the output currents concerning the photodetecting surface 11, 12.