U.S. Philips Corporation

Koninklijke Philips Corporation N.V.

James H Coombs

Antonius H Holtslag

Johan P Duchateau

Wilma Van Es-Spiekman

Petrus Theodorus Jutte

Bernardus A Jacobs

Guofu F Zhou

Mark Thomas Johnson

Josephus J Braat

Johannes H Spruit

Bastiaan Wilhelmus Maria Moeskops

Guo-Fu Zhou

Cornelis M Van Uijen

Adrianus P Jongenelis

Jacobus P Kroon

Jacob Sonneveld

Igolt P Ubbens

Yvonne A Boersma

Wilma Van Es Spiekman

The present application relates to a cutting head () for a device for cutting hair. The cutting head has an optical system () which directs a laser beam () across a cutting zone () in the cutting head. The laser beam has a fast and a slow axis. The optical system has a focus lens () configured to form a first focal point () of the laser beam in the cutting zone. In one embodiment, the optical system () also has a focusing element () which refocuses the laser beam to form a second focal point () of the laser beam in the cutting zone. In another embodiment, the focus lens forms a focal length of the laser beam in the cutting zone along its fast axis which is greater than a focal length of the laser beam in the cutting zone along its slow axis.

Cutting head for a device for cutting hair

An optical scanning device is described which can scan a record carrier by a radiation beam. A dividing element directs radiation reflected from the record carrier to a detection system. The detection system includes at least three detectors. The dividing element has at least three gratings, each forming a sub-beam directed to one of the detectors. The longest dimension of each detector is substantially perpendicular to the bisector of the appertaining sector.

Optical scanning device

A description is given of an reversible optical information medium comprising a substrate, a first dielectric layer, a phase-change recording layer on the basis of Ge--Sb--Te, a second dielectric layer, and a metal mirror layer. The recording layer comprises an alloy having the composition Ge.sub.50x Sb.sub.40-40x Te.sub.60-10x in atom %, wherein

Reversible optical information medium

A description is given of an reversible optical information medium comprising a substrate (1), a first dielectric layer (2), a phase-change recording layer on the basis of Ge-Sb-Te (3), a second dielectric layer (4), and a metal mirror layer (5). The recording layer (3) comprises an alloy having the composition Ge.sub.50x Sb.sub.40-40x Te.sub.60-10x, in atom %, wherein

A method is described for recording an optical information carrier, in which marks representing recorded data are written at different writing speeds by radiation pulse of equal length and power, independent of the writing speed. The number of pulses per unit length of the written mark is a constant independent of the writing speed.

Method and device for recording a mark having a substantially constant

An optical scanning device can scan two types of record carriers each having a transparent layer with a different thickness, in which a radiation beam scans an information layer of the record carrier through the transparent layer. When scanning a first type of record carrier the best focus of a scanning radiation beam is positioned on the information layer and when scanning a second type of record carrier the paraxial focus of the radiation beam is positioned on the information layer.

Device for optically scanning a recording medium by focusing the best

A description is given of an optical information carrier comprising a substrate (1), a thin reflective layer (5), a dielectric layer (7), a phase-change recording layer on the basis of GeTeSe (9), a dielectric layer (11), an opaque metal reflective layer (13) and a protective layer (15). The information carrier can be inscribed, erased and read by means of a laser-light beam a and, in the inscribed state, complies with the CD-industrial standard. The recording layer (9) comprises an alloy having the composition Ge.sub.x Te.sub.y Se.sub.z, in atom %, wherein

Optical information carrier

Information storage system, device and record carriers for improved erasing of information written on a record carrier. A radiation beam is focused on a recording layer of a record carrier containing phase-change material. Crystalline information areas are written on initially amorphous portions of the recording layer by means of the radiation beam having its intensity modulated in accordance with write pulses. The information areas are erased (and changed back into amorphous portions) by means of the radiation beam having its intensity modulated in accordance with erase pulses. The time duration of each of the erase pulses (and, therefore, the intensity of the radiation beam being modulated in accordance therewith to heat the recording layer) and the cooling time of the recording layer thereafter is short enough that areas of the recording layer which are heated during erasing to a temperature above the crystallization temperature of the recording layer but lower than the melting point of the recording layer remain above the crystallization temperature for a period of time which is shorter than the crystallization time for the recording layer. The recording layer may contain a track and have more crystallization nuclei proximate to a centerline of the track than away from the centerline. In addition, the record carrier may be such that its reflection is larger when the recording layer has an amorphous structure than when it has a crystalline structure.

Phase change record carries having crystalline nuclei and/or which

An optical record carrier with a substrate (1) having thereon a stack (3) of a reflection layer (4), an interference layer (5) and a phase-change recording-layer (6) in that order, the incident radiation being first incident on the reflection layer. Due to this structure of the stack a high contrast between the inscribed and uninscribed areas of the recording layer, and/or a high reflection, is obtained.

Optical record carrier

Information storage system, device and record carrier for improved erasing of information written on the record carrier. A radiation beam is focused on a recording layer of the record carrier containing phase-change material. Crystalline information areas are written on initially amorphous portions of the recording layer by means of the radiation beam having its intensity modulated in accordance with write pulses. The information areas are erased by means of the radiation beam having its intensity modulated in accordance with erase pulses. The time duration of each of the erase pulses (and, therefore, the intensity of the radiation beam being modulated in accordance therewith to heat the recording layer) and the cooling time of the recording layer thereafter is short enough that areas of the recording layer which are heated during erasing to a temperature above the crystallization temperature of the recording layer but lower than the melting point of the recording layer remain above the crystallization temperature for a period of time which is shorter than the crystallization time for the recording layer. The recording layer may contain a track and have more crystallization nuclei proximate to a centerline of the track than away from the centerline.

Information storage system and device for improved erasing of

The disclosed information reading system comprises a record carrier (1) having at least two parallel tracks (2a, 2b) whose mutual distance is so small that the radiation beam (10) is modulated by the information patterns of the two tracks (2a, 2b) when the tracks are scanned by a focused radiation beam (10) along a line (18) indicating the center between the tracks (2a, 2b). The tracks comprise elementary areas, with the positions of the boundaries (80) of the elementary areas of the two tracks, viewed in the track direction, corresponding to each other. The information patterns in the tracks comprise elementary areas occupied by a mark and unoccupied elementary areas. The occupied elementary areas have a different influence on the radiation than the unoccupied elementary areas. When the two tracks (2a, 2b) are scanned, the center (17) of the scanning spot (14) is directed onto a line (18) which is located centrally between the tracks (2a, 2b). A radiation beam modulated by the scanned information pattern is projected onto a detection system (12). The information (I1, I2, I) which has been read is at least partly derived on the basis of one or more detection signals (Vt, Vppr, Vppt, Vppd) which are supplied by the detection system (12) at the instants when the radiation beam passes the boundaries (80) of the elementary areas.

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Eindhoven, Netherlands

James H Coombs