| 摘要 |
PROBLEM TO BE SOLVED: To provide a beam irradiation apparatus capable of smoothly controlling a scanning position by simple constitution. SOLUTION: Electrostatic capacity type displacement sensors are arranged in the vertical and horizontal directions of a lens. When the lens is driven in the vertical direction, driving currents Ia, Ib at timing that electrostatic capacity reaches saturated capacities Ca, Cb are detected. A driving current Iym for positioning the lens on a vertically neutral position and a vertical lens shifting distanceΔyd per unit driving current are found out by following equation: Iym=(Ia+Ib)/2,Δyd=(Da+Db)/(Ia-Ib). Similarly a horizontal driving current Izm and a horizontal lens shifting distanceΔzd are found out. Driving currents in respective directions to a target area are set on the basis of the calculated driving currents Iym, Izm and lens shifting distancesΔyd,Δzd. Consequently the target area can be accurately irradiated with laser light. COPYRIGHT: (C)2007,JPO&INPIT
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