Abstract: The present invention relates to a method of reading out information from a multiple layer optical recording medium (10) by an optical readout device (12), the method comprising the steps of: focusing a central light beam (14) and two satellite light beams (16, 18) onto a first recording layer (20) of the optical recording medium, projecting reflection beams (22, 24) of at least part of the satellite light beams on two split detectors (26, 28), thereby creating satellite spots (116, 118), each split detector being associated with one of the satellite light beams, the reflected light interfering with light reflected by a second recording layer (21), and processing the signals from the split detectors for providing a tracking error signal, wherein the influence of a central part (29) of the reflection beams on the tracking error signal is removed and/or modified, thereby reducing a negative influence of this central part on the quality of the tracking error signal.

Abstract: The invention relates to an optical device comprising a first radiation source (101) for producing a first radiation beam, a second radiation source (101) for producing a second radiation beam and means for directing the first and second radiation beams along a common optical path. Each radiation beam has an intensity distribution, a central axis and an outer envelope. The optical device further comprises, in the common optical path, means (103) for modifying the intensity distribution of the first radiation beam only. This means are designed for increasing the ratio between the intensity near the envelope and the intensity near the central axis of the first radiation beam by reducing at least the intensity of the first radiation beam near its central axis.

Abstract: An optical scanning device for scanning optical record carriers having information layers at different information layer depths within the carrier, the optical record carriers including a first optical record carrier (3?) having an information layer (2?) at a first information layer depth d1, a second optical record carrier (3?) having an information layer (2?) at a second information layer depth d2 and a third optical record carrier (3??) having an information layer (2??) at a third information layer depth d3, wherein d3<d2<d1. The scanning device includes a radiation source system (7) for producing first, second and third radiation beams (4?; 4?; 4??), for scanning said first, second and third record carriers (3?; 3?; 3??), respectively, the device including a diffraction structure (48) introducing first, second and third, different, wavefront modifications into at least part of the first, second and third, radiation beams, respectively.

Abstract: The invention relates to an optical device comprising a radiation source (101) for producing a radiation beam and means (103, 106) for focusing the radiation beam on an information carrier (100) along an optical path. The radiation beam has a central axis, an outer envelope and an intensity distribution. The optical device further comprises, in the optical path, an optical component (104) designed for increasing the RIM intensity and thus the radio between the intensity near the envelope and the intensity near the central axis in that at least the radiation beam near the central axis is diffracted.

Abstract: In an optical scanning device for scanning an optical record carrier (20) and comprising a radiation source (2), a beam splitter (8) arranged to pass a first portion (b3) of the source beam (b1) to the record carrier and a second portion (b5) to an intensity sensor (10), and a signal detector (24) in the path of the beam reflected by the record carrier, false radiation (b6) reflected by the signal detector can be prevented from reaching the intensity sensor by tilting the signal detector. A polarization filter (40) may be arranged in front of the intensity sensor to prevent false radiation reflected by the radiation source and by the signal detector from reaching the intensity sensor.

Abstract: The invention relates to an optical scanning device for scanning in a first mode a first information layer (111) of an information carrier and in a second mode a second information layer (112) of the information carrier. The optical scanning device comprises a radiation source (101) for generating a radiation beam (102), an objective system (105) for focussing an entrance beam on an information layer and an optical element (103) arranged between the radiation source and the objective system, for converting said radiation beam into a diverging entrance beam in the first mode and a converging entrance beam in the second mode.