Abstract: An optical scanning device (3) for scanning a record carrier (2) comprises an objective unit (20) and a diffraction element (14). The objective unit (20) is adapted to transmit an auxiliary radiation beam (21) towards the record carrier (2) in a defocused mode in addition to a main radiation beam (6) that is used for read-out and/or writing operations. The diffraction element (14) defines a measuring region (16) with respect to a spot (44) of the main radiation beam (6) so as to avoid an influence of the auxiliary radiation beam (21) on the main radiation beam (6) reflected. Hence, the performance of read-out and/or writing operations is increased.

Abstract: An optical scanning device for scanning a record carrier (22), the record carrier having an outer face (24), wherein the optical scanning device comprises a radiation source system (2) arranged to generate radiation (3); an objective system (20) having an exit face (24), the objective system being arranged between the radiation source system and the record carrier; a radiation detector arrangement for generating detector signals representing information detected in the radiation after interaction with the record carrier; and a position control system (42) for controlling a gap size of a gap between the exit face of the objective system and the outer face of the record carrier, the position control system providing for evanescent coupling of the radiation across the gap.

Abstract: An optical data storage system for recording and/or reading, using a radiation beam having a wavelength X is described. The radiation beam is focused onto a data storage layer of an optical data storage medium. The medium has a cover layer that is transparent to the focused radiation beam. The cover layer has a thickness h smaller than 5 ?m. A cover layer with thickness variation of substantially less than the focal depth, i.e. 50 nm, eliminates the need of dynamic focus control of the objective which is otherwise required in addition to the gap servo. Further a method of optical recording is described using such an optical data storage system by which a static focus control and spherical aberration correction to accommodate medium-to-medium variance is achieved. The static focus control can be realised by optimising the modulation depth of a known signal, e.g. from a lead-in track.

Abstract: An optical data storage system for recording and/or reading, using a radiation beam, having a wavelength ?, focused onto a data storage layer of an optical data storage medium is described. The system comprises the medium having a cover layer that is transparent to the focused radiation beam, an optical head, including an objective having a numerical aperture NA, said objective including a solid immersion lens that is adapted for being present at a free working distance of smaller than ?/10 from an outermost surface of said medium. The optical head comprises a first adjustable optical element corresponding to the solid immersion lens, means for axially moving the first optical element and dynamically keeping constant the distance between cover layer and solid immersion tens, a second adjustable optical element, means for dynamically adjusting the second optical element for changing the focal position of the focal point of the focused radiation beam relative to an exit surface of the solid immersion lens.

Abstract: A device reads and/or records marks in a track on a record carrier via near field optical recording. The device has a head including a lens to be positioned at a near field distance from a surface of the record carrier. An air gap controller is for controlling an air gap between the lens and the surface, and has an approach mode for bringing the lens from a remote distance in the far field (72) to the near field distance. Thereto the controller provides an increasing periodical excitation signal (73) for generating a sequence of approach instants (77) at which the lens approaches the surface. At the approach instants the lens has substantially zero velocity (76). The sequence of approach instants brings the lens subsequently closer to the surface. When the lens enters in the near field range (71) at one of the approach instants (77), the air gap controller is switched to closed loop mode.

Abstract: The present invention relates to a focus control apparatus and method of controlling focus of a radiation beam onto a first spatial level of a record carrier, wherein a focus control loop is locked onto a reflection signal obtained from a second spatial level located at a predetermined distance from said first spatial level, and is then opened to move an objective means towards the second spatial level by a predetermined amount related to the predetermined distance. This stepwise procedure enlarges the margin for mechanical overshoot and hence reduces the risk of bumping into the disc. Additionally, no ambiguous focus error signals are detected and robustness of initial focusing is improved if a thin transparent cover layer is present.

Abstract: For optical data storage applications a near field optical system can be used. In near field optical systems an accurate control of the distance between the solid immersion lens and the disc surface is crucial. After the correction of a tilt between the lens and the disc, the laser beam may not always be parallel to the optical axis. This has a detrimental effect on the gap signal used for the distance control. The optical head of the invention comprises a gap signal correcting unit to take care of such detrimental effects.

Abstract: An optical pickup actuator for scanning an optical record carrier comprises a first section having an objective system and second section having an optical element with large position tolerances with respect to the objective system. For high bandwidth performance and/or low power dissipation a small movable actuated mass is preferred. A resilient member is connecting the second section to the first section.

Abstract: For optical data storage applications a near field optical system can be used. In near field optical systems an accurate alignment of a solid immersion lens with respect to a disc surface is crucial. The correction of a tilt between the lens and the disc is performed by use of auxiliary beams. By comparing the gap signal for the auxiliary beams the air gap height and disc tilt can be determined.

Abstract: A Method of Manufacturing an Integrated Magneto-Optical Element for use in a Digital Magneto-Optical Signal write/Read Head and an Integrated Magneto-Optical Element Manufactured According to the Method A method of manufacturing an integrated magneto-optical element for use in a digital magneto-optical signal read/write head, in which the manufacturing techniques of thin film coils are combined with lens-making techniques to realise a high performance, reliable and cost-effective lens-MFM coil combination for use in a slider having an air bearing surface for “flying” just above a surface of a storage medium (102) during operation. The method comprises two principal steps: Step I is to make an MFM coil (106) by means of a thin film technique, and Step 2 is to make an objective lens (114) on top of the transparent (e.g. glass) plate (109) in which the MFM coil (106) is located.

Abstract: An optical scanning device for scanning a record carrier (22), the record carrier has an outer face (24) and the optical scanning device comprises a radiation source system (2) arranged to generate a radiation beam; an objective system (20) having an exit face (76) and which is arranged between the radiation source system and the record carrier and provides for evanescent coupling of the radiation across a gap between the exit face of the objective system and the outer face of the record carrier; and a radiation detector arrangement for detecting radiation after interaction with the record carrier. The radiation detector arrangement is arranged to produce a tilt error signals (?, ?) representing a tilt misalignment between the exit face of the objective system and the outer face of the record carrier.

Abstract: An optical input device for measuring the movement of an object (15), e.g. a finger, is accommodated in a housing provided with a transparent window (12) for transmitting a measurement beam (13) from a diode laser (3) to the object (15) and radiation reflected by the object (15) to a detector, wherein changes in the operation of the laser cavity caused a laser diode self-mixing effect indicate the extent and direction of movement of the object. The angle of incidence (?) and/or the refractive index of the transparent window (12) nlens are selected so that at least a significant proportion of the measuring beam (13) is substantially totally internally reflected by the transparent window (12) when the object (15) is not in contact therewith. A device is also described in which at least a portion of the measuring beam (13) is directed toward a second transparent window (36) to provide a laser pointing function or enable the projection of messages or images.

Abstract: The present invention relates to a storage medium (10) comprising an information layer (11) including transparent and non-transparent areas in which the information is stored, and a magnetizable layer (12) intended to contain at least one magnetized area, which is temporarily created when a light spot is transmitted by a corresponding transparent area of the information layer. The present invention also relates to a reading device for reading information on such a storage medium (10). Said reading device comprises an optical element (23) for generating an array of light spots from an input light beam (21), a light spot being intended to temporarily create the magnetized area in the magnetizable layer (12) when passing through the corresponding transparent area of the information layer (11), and a magnetic sensor (24) comprising an array of sensor elements for detecting the at least one magnetized areas.

Abstract: In an optical storage interface apparatus, a spot-forming lens projects a light spot on an optical information carrier in response to a light beam from a light source. There is an air gap (AG) between the spot-forming lens and the optical information carrier. A gap detector (PHD2) provides a gap indication signal (GIS) that varies with the air gap (AG) in accordance with a gap indication transfer function (F). A lens-positioning arrangement (CTRL, ACT) positions the spot-forming lens with respect to the optical information carrier on the basis of the gap indication signal (GIS). The lens-positioning arrangement (CTRL, ACT) comprises a compensator (CMP) for compensating nonlinearity in the gap indication transfer function (F). A suitable compensation transfer function (G) can be established on the basis of servo control loop measurements. Accordingly, compensation can be provided without any prior knowledge of the gap indication transfer function (F).

Abstract: Magneto-optical device comprising a magneto-optical read and/or write head with a coil (5), and a means for generating a laser beam (1), wherein the laser beam is passed through an aperture (12) in the coil (5) during operation, characterized in that the coil holder comprises a recess at or around the position of the optical center of the coil, and a lens (4) extends, viewed from the disk, behind the coil, overlapping the coil at least partly.

Abstract: The present invention relates to a domain expansion storage medium and manufacturing method with improved readout performance. The substrate of the storage medium and/or its storage layer is processed to define a predetermined shape of magnetic domains, adapted to the front of the thermal reading profile. In particular, reversed crescent shaped domains flipped in the track directions are defined. This allows improved resolution and jitter values.

Abstract: An actuator (6) for a magneto optical recording apparatus (1) comprises an actuator base (20); a platform (30) movably coupled to said actuator base (20); at least one actuator coil (31) supported by said platform (30); at least one writing coil (43) supported by said platform (30). One common conductor (22a; 22b) conducts actuator coil drive signals as well as writing coil drive signals from said actuator base (20) to said platform (30).

Abstract: Apparatus for optically scanning an information plane of a disc-shaped optical record carrier having an underlying surface extending parallel to the information plane. A radiation source supplies a scanning beam, and an optical scanning unit has a lens system which focuses the scanning beam to a scanning spot on the information plane. The lens system has an optical axis, a first lens unit with a first lens having an entrance side (11) and an exit side (13), and a second lens unit with a second lens situated opposite the exit side of the first lens. The scanning unit also includes a drive motor for displacing the first lens along the optical axis and a rotation element for adjusting the position of the second lens with respect to the underlying surface of the record carrier. To inhibit spherical and/or comatic and astigmatism aberrations during scanning, the rotation element is rotatably driven and forms part of the second lens unit.