Patent ID: 6333499
Filing Date: 2001-12-25
Classification: G01N

Abstract:
A method of detecting a reading start point which starts reading information in a horizontal scanning direction or a recording start point which starts recording information in said horizontal scanning direction, by relatively moving a predetermined medium to be scanned and/or a scan head, which reads said information from said medium or records said information on said medium, by horizontal scanning means so that said scan head can reiteratively perform horizontal scanning in a fixed direction with respect to said medium, said method comprising the steps of:generating two rotational angle pulse signals having a phase difference which varies according to a rotational direction of a rotary drive means provided in said horizontal scanning means;causing said horizontal scanning direction to depend on the rotational direction of said rotary drive means;detecting reversal of the rotational direction of said rotary drive means, based on said phase difference between said two rotational angle pulse signals;detecting said rotational angle pulse signals from the reversal of said rotational direction; anddetecting said scanning start point, based on the detected rotational angle pulse signals.