Abstract: An information storage system is described which comprises a reading device (6) and an optical record carrier (5) having at least two information planes (1, 2, 3). The radiation from the record carrier is converted in a detection system (15) into a detection signal (16) which is applied to a detection circuit (17). In order that this circuit can derive the read information from the detection signal in a reliable manner, the interference signals generated by the information planes which are not to be read should comply with a requirement, referred to as the interference requirement, which is characteristic of the detection circuit. Values for the parameters of the record carrier, such as the thickness of the layers between the information planes and the reflection and transmission coefficients of the information planes then follow from this interference requirement.

Abstract: An optical information storage system has a multi-recording-layer record carrier and a scanner device for the carrier. The scanner produces a radiation beam which is compensated for spherical aberration for a single height of the scanning spot with the stack of layers. The height of the stack is determined by the maximum spherical aberration permissible for the system. The number of layers in the stack is determined by the minimum distance between layers, which depends on the crosstalk in the error signals due to currently unscanned layers.

Abstract: A method of displaying a video signal (Vs) with m video lines in a video field period on a plasma display panel (1) which has n display lines (Di), includes selecting (2) the n display lines (Di) in an interlaced way to subsequently select a first and a second field of n/2 display lines (Di) to display an interlaced video signal (Vs). For displaying a progressive video signal (Vs), the m video lines are alternately displayed (3) on the first field of display lines (Di) only, or on the second field of display lines (Di) only, both during respective time periods which are longer than the video field period.

Abstract: A method of displaying an interlaced video signal (VS) on a matrix display panel (1) which is sub-field and interlaced driven and comprises a first and a second display field (Df1, Df2) forming interlaced display lines (Di), said interlaced video signal (Vs) having frames with a first and a second video field (Vf1, Vf2). During the frame period (Tfr) of the video signal (Vs), at least a first and a second display period (Td1, Td2) are generated. During each display period (Td1, Td2), the first and the second display field (Df1, Df2) are alternately selected for displaying video information related to the first and the second video field (Vf1, Vf2), respectively. The sub-field weights associated with the first and the second display field (Df1, Df2) of the first display period (Td1) differ by at least one weight from sub-field weights associated with the first and the second display field (Df1, Df2) of the second display period (Td2).

Abstract: An optical information storage system has a multi-recording-layer record carrier and a scanner device for the carrier. The scanner produces a radiation beam which is compensated for spherical aberration for a single height of the scanning spot with the stack of layers. The height of the stack is determined by the maximum spherical aberration permissible for the system. The number of layers in the stack is determined by the minimum distance between layers, which depends on the crosstalk in the error signals due to currently unscanned layers.

Abstract: An optical information storage system has a multi-recording-layer record carrier and a scanner device for the carrier. The scanner produces a radiation beam which is compensated for spherical aberration for a single height of the scanning spot with the stack of layers. The height of the stack is determined by the maximum spherical aberration permissible for the system. The number of layers in the stack is determined by the minimum distance between layers, which depends on the crosstalk in the error signals due to currently unscanned layers.

Abstract: An image display panel includes a number of channels extending in a first direction. First electrodes extend parallel to the channels and a pair of second electrodes extend perpendicular to the channels. An image cell is created at the position where the pair of second electrodes cross a crossing of a first electrode. An array of cylindrical lenses is arranged on the viewer's side of the panel each having a longitudinal axis substantially parallel to the second electrodes. The pitch of the lens array may be equal to the vertical pitch of the image cells, while the array is shifted with respect to the image cells in a direction substantially perpendicular to the second electrodes. Also, the pitch of the lens array may be smaller than the vertical pitch of the image cells with or without with the aforementioned shift of the lenses with respect to the image cells.

Abstract: A picture display device comprising a cathode ray tube of the index type has two patterns of index elements which are electrically separated and each generate separate signals. A first pattern, which is preferably positioned at the blind edge of the display screen, can detect large-scale and, hence, low-frequency disturbances. A second pattern, which preferably extends in the visible part of the display screen, can detect high-frequency disturbances.

Abstract: A drive circuit for a CRT locally enhances the drive signal range in a window. Circuitry is further included for monitoring the average luminosity in the window, and the drive signal range is reduced if there is a danger of doming in the window.

Abstract: A flat panel display comprises a plurality of display elements (C) arranged in a matrix of rows (R) and columns, and first and second electrodes (Sc, Su) which are aligned with respect to each other and extend in a row or a column direction. The first and second electrodes (Sc, Su) form pairs which are associated with same display elements (C). An amount of electro-magnetical interference caused by currents through the first and second electrodes (Sc, Su) is decreased by driving the first and second electrodes (Sc, Su) in at least two groups such that the pairs are divided in two groups, and such that currents in pairs belonging to different groups flow in opposite directions.

Abstract: An information storage system is described which comprises a reading device (6) and an optical record carrier (5) having at least two information planes (1, 2, 3). The radiation from the record carrier is converted in a detection system (15) into a detection signal (16) which is applied to a detection circuit (17). In order that this circuit can derive the read information from the detection signal in a reliable manner, the interference signals generated by the information planes which are not to be read should comply with a requirement, referred to as the interference requirement, which is characteristic of the detection circuit. Values for the parameters of the record carrier, such as the thickness of the layers between the information planes and the reflection and transmission coefficients of the information planes then follow from this interference requirement.

Abstract: An information storage system is described which comprises a reading device (6) and an optical record carrier (5) having at least two information planes (1, 2, 3). The radiation from the record carrier is converted in a detection system (15) into a detection signal (16) which is applied to a detection circuit (17). In order that this circuit can derive the read information from the detection signal in a reliable manner, the interference signals generated by the information planes which are not to be read should comply with a requirement, referred to as the interference requirement, which is characteristic of the detection circuit. Values for the parameters of the record carrier, such as the thickness of the layers between the information planes and the reflection and transmission coefficients of the information planes then follow from this interference requirement.

Abstract: An optical information storage system has a multi-recording-layer record carrier and a scanner device for the carrier. The scanner produces a radiation beam which is compensated for spherical aberration for a single height of the scanning spot with the stack of layers. The height of the stack is determined by the maximum spherical aberration permissible for the system. The number of layers in the stack is determined by the minimum distance between layers, which depends on the crosstalk in the error signals due to currently unscanned layers.

Abstract: An optical information storage system has a multi-recording layer record carrier and a scanner device for the carrier. The scanner produces a radiation beam which is compensated for spherical aberration for a single height of the scanning spot with the stack of layers. The height of the stack is determined by the maximum spherical aberration permissible for the system. The number of layers in the stack is determined by the minimum distance between layers, which depends on the crosstalk in the error signals due to currently unscanned layers.

Abstract: A reading device (6) and an optical record carrier (5) having at least two information planes (1, 2, 3). The radiation from the record carrier is converted in a detection system (15) into a detection signal (16) which is applied to a detection circuit (17). In order that this circuit can derive the read information from the detection signal in a reliable manner, the interference signals generated by the information planes which are not to be read should comply with a requirement, referred to as the interference requirement, which is characteristic of the detection circuit. Values for the parameters of the record carrier, such as the thickness of the layers between the information planes and the reflection and transmission coefficients of the information planes then follow from this interference requirement.

Abstract: 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.

Abstract: 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.

Abstract: A method of and an apparatus for writing and reading and/or erasing a multilayer record carrier (1) having a guide plane (2) and a plurality of recording planes (4) are described, using a guide beam (5) which cooperates with the guide plane (2) and a scanning beam (6) for at least writing in the recording planes (4). During writing the position of the scanning focus (36) formed by the scanning beam (6) is coupled to the focus (11) of the guide beam (5) which is actively controlled by using guide information which is present in the guide plane (2). During reading the scanning beam (6) is actively controlled by its own servosystem (20-28).

Abstract: 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.

Abstract: Recording and/or reading of information on an optical record carrier is effected by scanning such record carrier with a radiation beam which is focussed by an objective lens into a scanning spot of a size which is diffraction-limited by the aperture of the objective lens. The effective size of the scanning spot is considerably reduced by including a layer of non-linear optical material in the record carrier, such material having an optical characteristic which changes with changes in intensity of the radiation incident thereon. The read/write resolution of information on the record carrier is thereby substantially increased.