PHOTOVOLTAIC SENSOR

PROBLEM TO BE SOLVED: To stably keep specific error characteristics of output voltage, regardless of variation in the relative humidity by placing a photosensor section in a case isolated from the external environment and encapsulating a dry gas. SOLUTION: A photosensor section 6 and a drying agent 7 are bonded, first, into the box type container 1a of a watertight box 1. Voltage applying lines 2a, 2b and optical fibers 3, 4 are then passed through-holes 1e-1h of the watertight box 1 and connected with the photosensor section 6. The holes 1e-1h are sealed with an adhesive. Subsequently, a temperature sensor 5 is inserted into a hole 1i which is then sealed similarly. Thereafter, the watertight box 1 is placed in the air of 0 deg.C, having relative humidity of 0-20% and assembled by means of bolts 1d, while sandwiching a packing 1c between the box type container 1a and a cover 1b thus isolating the photosensor section 6 from the external environment. Drying gas, e.g. nitrogen gas, may be encapsulated. According to the structure, variation in performance is prevented at the photosensor section comprising an optical crystal, regardless of variation of relative humidity in addition to temperature variation.