| 摘要 |
PURPOSE:To remove noise light components other than a signal luminous flux effectively by processing signals from respective detection areas of a detecting means by using a specific window function. CONSTITUTION:The luminous flux from a light source 31 is collimated by a collimator lens 32 into parallel luminous flux, which irradiates a 1st physical optic element 41M as a 1st object 1 slantingly through a projection lens 31 ad a half-mirror 34. The 1st physical optic element 41M converges the light beams to unit the reflected light beams in the normal direction of the 1st body and the light beams are made incident on a 2nd physical optic element 41W as a 2nd body 2 which is placed at a specific distance from the 1st physical optic element 41M. This 2nd physical optic element 41W units the luminous flux toward an alignment head 24 and the light beams are converted on the detection surface of a detector 38 through a condenser lens 36. Then, the output signal of the detector 38 is adjusted to find the quantity of the position shift between the 1st and 2nd body 2 on a plane. |
