U.S. Philips Corporation

Koninklijke Philips Corporation N.V.

Gerard E Van Rosmalen

Willem G Opheij

Josephus A Kahlman

Wilhelm J Kleuters

Wilhelmus A Gijzen

Hugo Johan Cornelissen

Gerardus A Vrijssen

Martinus P Bierhoff

Willem Gerard Ophey

Peter J Janssen

Kornelis A Immink

Herman G Lakerveld

Karl-Hanns Meyer

Cornelis J Savert

Leonhard Honds

Helmar Van Santen

Josephus Arnoldus Henricus Maria Kahlman

Arthur M Hoeberechts

Johannes H Spruit

Bernardus A Jacobs

Josephus A H M Kahlman

Gerard Van Engelen

Antonius A Van Alem

Jan Willem Aarts

Gerrit B Gerritsen

Robert N Van Sluys

Jan Peter Baartman

Adrianus P Jongenelis

Pieter A Schoneveld

Renso J Zwiers

Marcus Jh Willems Van Dijk

Johannes Petrus Sinjou

Bob Hoekstra

Willy J Aerts

Gerardus C Dortant

Kornelis Bulthius

A device for reading and/or writing a disc-shaped information carrier which comprises a support element of a magnetizable material along its circumference. An electromagnetic unit cooperates with the support element and a scanning unit for reading and/or writing the information carrier, which can be rotated about an axis of rotation and positioned with respect to the scanning unit in five degrees of freedom except for the rotational degree around the axis of rotation.

Device for scanning an electromagnetically suspended information carrier

The invention relates to a method of manufacturing a master mold ( ), which is used to manufacture an optical information disc, such as a CD or DVD. According to the method, a substrate ( ) is provided with a photosensitive layer ( ), which is subsequently irradiated by means of a radiation beam ( ), which is focused to a scanning spot ( ) on said layer by means of an optical lens system ( ). A liquid, such as water, is supplied into a gap ( ) present between the photosensitive layer and an auxiliary lens ( ) of the lens system facing said layer. As a result, the size of the scanning spot is decreased and the information density of the information disc to be manufactured is increased. According to the invention, the liquid is supplied via a supply opening ( ) which is positioned immediately adjacent the auxiliary lens ( ), in a direction which, viewed from the scanning spot ( ), is contrary to a direction (Z) wherein the substrate ( ) is moved with respect to the lens system ( ). Thus, the liquid supplied via the supply opening is transported immediately and exclusively into said gap ( ), so that the amount of liquid to be supplied to fill the gap is limited. The supply opening is formed in a wall portion ( ), which extends in an imaginary plane in which also a side wall ( ) of the auxiliary lens ( ) facing the photosensitive layer is present. As a result, a homogeneous Couette flow of liquid without air inclusions is obtained in the gap. This Couette flow does not cause any undesirable mechanical vibrations of the lens system. The invention further relates to a method of manufacturing an optical information disc, according to which method a master mold ( ) is manufactured in a first step, and the information disc is manufactured in a second step by means of a replica process using said master mold. The invention further relates to a device ( ) for the manufacture of a master mold by means of a method according to the invention.

Method of manufacturing an optically scannable information carrier

An optical scanning device includes a radiation source; an optical lens system with an optical axis for focusing a radiation beam supplied, in operation, by the radiation source into a scanning spot on an information carrier, the lens system including a housing, a first lens which is secured in the housing in a fixed position, and a second lens which, viewed in a direction parallel to the optical axis, is elastically suspended in the housing; a first actuator for displacing the lens system in a direction parallel to the optical axis; a first control unit for controlling the first actuator by means of a first control signal; a second actuator for displacing the second lens relative to the first lens in a direction parallel to the optical axis; and a second control unit for controlling the second actuator by means of a second control signal, and in which during operation, the first control unit also controls the second actuator by means of a third control signal which is proportional to the first control signal.

Optical scanning device with parallel-controlled actuators

An optical disk drive for reading and/or writing information from/on an optical disk includes an auxiliary lens to compensate for optical aberrations and a servo loop for positioning the auxiliary lens relative to a main lens. The servo loop includes an actuator for driving the auxiliary lens and a controller to feed the actuator coil with a drive current dependent on a position signal which is derived from the actual inductance of the actuator coil and a reference signal which indicates a desired position of the scan element. The disk drive also includes an inductance influencing device to vary the inductance of the actuator coil as a function of the position of the scan element.

Apparatus for reading and/or writing information from/on a recording medium

An optical scanning device for scanning an optically readable record carrier (1) includes a radiation source (5), a radiation-sensitive detection system (7), and an optical scanning unit for focusing a scanning beam (3) produced by the radiation source to a scanning spot (9) on the record carrier. The scanning unit including a lens system having an optical axis (13), which lens system includes a first lens unit having a main lens (15) and a second lens unit having an auxiliary lens (17). The scanning device further includes a first detection unit involved in detection of the main lens with respect to the record carrier, and a second detection unit involved in detection of the auxiliary lens. The scanning unit further includes a first electrical drive unit for moving the first lens unit in dependence upon a signal supplied by the first detection unit, and a second electrical drive unit for moving the second lens unit with respect to the main lens in dependence upon a signal supplied by the second detection unit. The second drive unit includes a first part and a second part which cooperates with the first part via an air gap (51). The first part is secured to the first lens unit and the second part is secured to the second lens unit. In order to counteract spherical aberration and/or coma and/or astigmatism during scanning the second detection unit includes a position and orientation detector system for detecting the position and orientation of the auxiliary lens with respect to the record carrier during scanning.

Optical scanning unit having a main lens and an auxiliary lens

A scanning device for an optical disc record carrier includes a turntable and a positioning device which is movable relative to the turntable in a plane transverse to the axis of rotation thereof. The positioning device includes a radiation source unit and an actuator unit having a carrier which supports several different objective lenses and which is movable parallel to the access of rotation. The scanning device further includes actuating apparatus for moving the actuator unit and the radiation source unit relative to one another between discrete operating positions in at least the plane transverse to the axis of rotation, so as to place a respective lens in position for scanning a respective one of several different types of optical discs having mutually different substrate thicknesses and/or information densities.

Scanning device for optical discs

An optical unit for optically scanning a surface, particularly an information surface of a recording medium. The unit may include a frame, a radiation source unit, a rotatable mirror unit, and an objective system for forming a scanning spot on the information surface. The objective system has an entrance pupil and an optical axis. From an optical point of view, the rotatable mirror unit is situated between the radiation source unit and the objective system, suspension means being provided for movably supporting the objective system relative to the frame. The suspension means allow a longitudinal movement of the objective system along the optical axis and a pivotal movement of the objective system about a pivot which coincides with the point of intersection of the optical axis and the entrance pupil. Actuating means drive the objective system in accordance with these movements. Alternatively, the optical unit may include an optical beam deflection unit. In this embodiment and from an optical point of view, the deflection unit is situated between the radiation source unit and the objective system and the suspension means allow a pivotal movement of the objective system about a pivot which at least coincides with the point of intersection.

Optical unit for optically scanning an information surface, and optical

A device for electromagnetically scanning information tracks on a record carrier, such as an optical tape, via a scanning beam is described. On this tape, information tracks are arranged substantially parallel and substantially transverse to a transport direction of the record carrier. The device is provided with a scanning unit for scanning, with the beam always following parallel scanning paths, and a control system for controlling an angle of the scanning paths with respect to the transport direction, dependent on a tilt signal. According to the invention, the device is provided with angle-measuring means for generating the tilt signal dependent on a tracking error signal which is indicative of a difference between a scanning path and the relevant information track. In addition to a tilt signal, a speed signal may also be derived from the tracking error signal. Both the tilt signal and the speed signal are derived from the tracking error signal in a captured and in a non-captured state of operation.

Device for scanning information tracks on a record carrier

An optical apparatus for scanning a tape-shaped record carrier, which apparatus uses a mirror polygon for scanning tracks extending perpendicularly to the tape travel direction. Since at least one facet, or a part thereof, of the mirror polygon extends at a different angle to the axis of rotation, the scanning spot is periodically moved transversely to the track direction, so that a tracking signal can be generated.

Optical apparatus for scanning a tape-shaped record carrier

An optical scanning device is described, which is provided with a scanning element having a reflecting measuring reference face (31), and a position detection system (80) which supplies, inter alia, a measuring signal (S.sub.z) for the position of the scanning element in a direction perpendicular to the reference face. By implementing the scanning element in a very thin form and by correcting said measuring signal (S) by means of the polygon bending signal (S.sub.b) supplied by the position detection system, a very rapid and accurate scanning can be realized.

Optical scanning device, and apparatus provided with such a device,

An electron-beam-pumped laser includes a cathode ray tube containing a laser crystal, an electron gun for producing an electron beam including a multi-element focusing electrode layer on an inner surface of the tube for effecting focusing of the beam on the laser crystal, and a multi-element deflection electrode layer on an inner surface of the tube for effecting scanning of the beam across the laser crystal. The laser crystal is disposed on a metal heat-conductive support which is adapted for accurately positioning the laser crystal in closely spaced relationship with respect to the electron gun and to a laser light emitting window of the tube.

Rapidly scanning cathode-ray tube laser

A position detection system (80) is described for detecting movements of an object (20) in at least five degrees of freedom, which system comprises a radiation source (33), a beam splitter (36) for forming a first measuring sub-beam (45) and a second measuring sub-beam (50), a reflector (38) arranged in the path of one of these measuring beams (45, 50) and a composite radiation-sensitive detection system (60). The first measuring sub-beam (45) is used for detecting displacements along three mutually perpendicular axes (X, Y, Z), and the second measuring sub-beam (50) is used for detecting rotations about at least two of these axes.

Position detection system for an object with at least five degrees of

An optical unit (1) is provided for optically scanning a surface, particularly an information surface of a recording medium (9). The unit comprises a frame (13), a radiation source unit (15), a rotatable mirror unit (17), and an objective system (19) for forming a scanning spot on the information surface, which objective system has an entrance pupil (19b) and an optical axis (19a). From an optical point of view, the rotatable mirror unit is situated between the radiation source unit and the objective system, suspension means being provided for movably supporting the objective system relative to the frame. The suspension means allow a longitudinal movement of the objective system along the optical axis and a pivotal movement of the objective system about a pivot which coincides with the point of intersection of the optical axis and the entrance pupil. Actuating means drive the objective system in accordance with these movements.

A tape-like record carrier (109) is disclosed which comprises paths (A, B). Each path (A, B) contains substantially parallel tracks (1) the path width (1s) in length and the direction of the tracks is transverse to the longitudinal direction of the path (A, B). The diameters (10) of the paths have various directions. The ends of the paths (1) are overlapping. In these overlapping areas the tracks (1) belonging to the various paths are positioned in interlineated manner. Said record carrier (109) is advantageous in that no time is lost during recording or reading when a path is changed. Furthermore, a recording and reading device is disclosed which are applicable in combination with the record carrier.

Record carrier, recording device and reading device

A scanning device for repeatedly scanning a scanning surface of a record carrier (e.g., a tape) by means of a first and a second scanning spot produced by respective scanning beams. The scanning spots perform synchronous movements along a first and a second scanning path, respectively, having different given scanning directions, as a result of which, the distance, viewed in a direction transverse to the scanning paths, between the first and the second scanning spot changes during scanning. The scanning device can be used in a recording and/or read apparatus which further includes a detection system for converting radiation emanating from the second scanning spot into a corresponding detection signal, and a measurement circuit which derives a position measurement signal indicative of deviation of track pitch based on a deviation in a relationship between the detection signal and a reference signal indicative of the position of the first scanning spot on the first scanning path. Other circuits can also be employed to derive a speed measurement signal indicative of the speed of the first scanning spot in a direction transverse to the track direction and a quality measurement signal indicative of the quality of an information pattern at the location of tracks traversed by the second scanning spot. If during reading a third scanning spot is used such that the second and the third scanning spot are always disposed symmetrically relative to the first scanning spot, corresponding detection signals can be obtained which can be used for deriving an inclination measurement signal indicative of the angle between the track direction and the first scanning path.

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Eindhoven, Netherlands

Gerard E Van Rosmalen