Patent ID: 8203925
Filing Date: 2012-06-19
Classification: G11B

Abstract:
1. Apparatus for recording angular multiplexed pits on an optical recording medium, wherein a rotation angle of an angular multiplexed pit represents several bits of information, wherein the apparatus is configured to perform the steps of: introducing a phase shift of 180 degrees in a first half of the recording light beam relative to a second half of the recording light beam with a liquid crystal element comprising electrodes that are sectors of a circle; setting an orientation of a border between the first half of the recording light beam and the second half of the recording light beam relative to an optical axis of the recording light beam to a first orientation of at least two different orientations in accordance with a rotation angle of a first pit to be recorded; recording the first pit on the optical recording medium by illuminating the optical recording medium with the recording light beam; setting the orientation of the border between the first half of the recording light beam and the second half of the recording light beam relative to the optical axis of the recording light beam to a second orientation different from said first orientation in accordance with a rotation angle of a second pit to be recorded; and recording the second pit on the optical recording medium by illuminating the optical recording medium with the recording light beam; wherein the orientation of the border between the first half of the recording light beam and the second half of the recording light beam is set by selectively applying a voltage to one half of the electrodes of the liquid crystal element.