PURPOSE: To realize highly accurate detection of field by providing an optical transmission means having a liquid crystal section disposed in the way of an optical transmission path, and means for converting a quantity of light passed through the liquid crystal section into a quantity of electricity.
CONSTITUTION: A liquid crystal section 2 is connected with a ground electrode 11 and an electrostatic electrode 12 and applied with the potential difference thereof. The liquid crystal section 2 is disposed in the way of an optical transmission path at an optical transmission section 3 in order to transmit the light. An optoelectric conversion means connected through the optical transmission section 3 with the liquid crystal section 2 comprises an optoelectric conversion element and transmits an electric signal corresponding to the quantity of transmitted light to an operating section. The operating section processes the quantity of light to operate the strength of field being applied to an electrostatic sensitive section 1 and delivers an operated signal to a display section in order to display the strength of field. When the liquid crystal section is constituted of a combination of a plurality of transparent electrodes and provided with a linearly variable section, sensitivity and accuracy can be enhanced in the detection of field strength.
OKASATO AKIRA
KOJIMA YASUO
NAKAMURA KOICHI
TAWARA TOKUO
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