Patent application number | Description | Published |
20080212436 | Optical Pick-Up and/or Recording Device - 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. | 09-04-2008 |
20080232216 | Focus Control Scheme with Jumping Focal Point - 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. | 09-25-2008 |
20080267036 | Air Gap Servo for Optical Recording - 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 ( | 10-30-2008 |
20080279064 | Optical Data Storage System and Method of Optical Recording and/or Reading - 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 μm. 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. | 11-13-2008 |
20080279070 | Optical Data Storage System and Method of Optical Recording and/or Reading - An optical data storage system for recording and/or reading, using a radiation beam, having a wavelength λ, 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 λ/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. This achieves reliable read-out and writing during cover layer thickness variations. Further a method is described for controlling such a system. | 11-13-2008 |
20090028037 | OPTICAL SCANNING DEVICE - An optical scanning device for scanning a record carrier ( | 01-29-2009 |
20090109825 | OPTICAL SCANNING DEVICE - An optical scanning device ( | 04-30-2009 |
20090190461 | OPTICAL DATA STORAGE SYSTEM FOR RECORDING AND/OR READING AN OPTICAL DATA STORAGE MEDIUM FOR USE IN SUCH SYSTEM - Multi layer near-field optical recording using a moderate numerical aperture (NA) is superior to the high-NA (NA=2.0) first-surface single-layer technique. The use of very flat and thin spacer layers limits spherical aberration due to difference in layer depth. The thin spacer layers may have a high refractive index because their thickness allow for a relatively high absorption constant. This makes possible in principle an m-layer system, e.g. m=4, with NA=1.6 which may include a flat, protective cover layer. Further a medium for use in such a system is described. | 07-30-2009 |
20090219790 | MAGNETO OPTICAL DEVICE - In a magneto optical device is which a laser beam is shone in operation through a coil ( | 09-03-2009 |
20110127552 | LIGHT OUTPUT DEVICE - The present invention relates to a light output device ( | 06-02-2011 |