Browse Prior Art Database

Drive Orientation Free Focus Acquiring Method

IP.com Disclosure Number: IPCOM000119658D
Original Publication Date: 1991-Feb-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Kagami, N: AUTHOR [+3]

Abstract

Disclosed is a method for moving an optical pickup away from an optical disk surface before the focus acquisition process. This method is widely applicable to any optical pickup system. This method allows usage of the optical disk driver in any orientation posture without any special mechanism or any electrical circuit.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 92% of the total text.

Drive Orientation Free Focus Acquiring Method

      Disclosed is a method for moving an optical pickup away
from an optical disk surface before the focus acquisition process.
This method is widely applicable to any optical pickup system.  This
method allows usage of the optical disk driver in any orientation
posture without any special mechanism or any electrical circuit.

      In this method, the focus servo system which is already
provided is used to remove the head from the disk surface. A focus
servo system generally includes an electrical focus offset correction
circuit.  This method uses the focus offset correction circuit to
allow the usage of the drive in any orientation posture.  The method
will be well understood with reference to the flowchart which
sequentially shows the steps of the method.
      Step 1:  Turn of a laser.
      Step 2:  Apply an electrical focus offset value to the
                offset correction circuit.  This offset value
                is large enough to move an optical pickup.
      Step 3:  Turn on a focus servo system.  At this moment
                an objective lens is pulled down far from a
                disk media surface.
      Step 4:  Wait for pickup to be in a stable condition.
      Step 5:  Turn on the laser.
      Step 6:  Wait for the laser power to be in a stable
                condition.
    ...