LEVEL UTILIZING SEMICONDUCTOR SENSOR

PURPOSE:To measure levelness with high precision by arranging an optoelec tromotive force type semiconductor sensor in a case provided with a slit which stops down irradiation light at the upper part. CONSTITUTION:The level 1 is provided with the case 2, the slit 3 at the upper part of the case, and the optoelectromotive force type semiconductor sensor 4 at the internal bottom part of the case. Light entering the case 2 through the slit 3 illuminates the semiconductor sensor 4 to generate a potential difference between electrodes 5a and 5b positioned on the same plane parallel to a faying surface, and this electromotive force varies linearly, so the potential between the electrodes 5a and 5b is measured and utilized to measure the irradiation position of the light. When the levelness is measured, the level 1 on a body to be measured is irradiated with light and then the output signal of the level 1 is inputted to an MPU10 as a control signal through an amplifier 9 and compared with a reference signal to sends the position signal of a positioner 8 to a positioner controller 11. Thus, the levelness of the body 7 to be measured is known and the levelness is adjusted on the basis of said levelness.