Focusing control method for reading/writing optical disc

Abstract

An optical reading/writing apparatus has an optical head that includes a collimator and a lens. For focusing control, a startup procedure is executed to generate a first startup S-curve. A boundary is then set according to the startup S-curve. After executing focusing on and tracking on, a plurality of position combinations of the collimator and the lens are selected for focusing calibration, thereby obtaining respective focusing error signals. By comparing the focusing error signals with the boundary, whether the position combinations of the selected collimator and the lens are valid can be determined. One of the valid position combinations with the greatest image-quality value is then selected to read/write the optical disc in the subsequent reading/writing procedure.

Dependencies are inferred from the claim text.