| 摘要 |
PURPOSE:To focus a spot and to align a slit by receiving the regularly reflected light from front and rear faces of a bending substrate by a CCD sensor to calculate the vertical extent of movement and the angle of inclination of the substrate. CONSTITUTION:The spot to which a laser beam L is focused is made incident at an angle phi on a glass substrate S, and the regularly reflected light from front and rear faces of the substrate S is received by the CCD sensor to measure the variation of the light reception position. A vertical extent DELTAZ of movement and an angle DELTAtheta of inclination of the substrate are calculated based on a prescribed formula in accordance with the angle phi of incidence and regular reflection, the refractive index and the thickness of the substrate S, the variation of the light reception position, and the distance between the spot and the CCD sensor. The substrate or a defect detecting optical system is vertically moved by DELTAZ to focus the spot, and the slit of a light reception system is moved by the angle 2DELTAtheta and is aligned. |
