Abstract: Optical information carrier comprising an optically transparent layer and a reflective layer adjacent to each other, and the interface between the layers comprises an optically readable information structure containing alternate areas with such different properties that a scanning light beam is modulated in correspondence with the information present in the structure. In the interface between the optically transparent layer, and the surface of the reflective layer, multiple gas-filled interconnected buffer spaces are provided at positions distributed over the interface, so as to provide for vapor pressure equalization across the carrier structure to maintain its flat shape.

Abstract: Optical information carrier comprising an optical transparent layer and a reflective layer adjacent to each other whereby the interface comprises an optically readable information structure containing alternate areas with such different properties, so that a scanning light beam is modulated in correspondence with the information present in said structure. Between the surface of the transparent layer and the surface of the reflective layer one or more gas-filled interconnected buffer spaces are realized at positions distributed over the interface between said layers.

Abstract: Optical information carrier comprising an optically transparent layer and a reflective layer adjacent to each other whereby the interface comprises an optically readable information structure containing alternate areas with such different properties, so that a scanning light beam is modulated in correspondence with the information present in said structure. Between the surface of optically transparent layer and the surface of the reflective layer, one or more gas-filled interconnected buffer spaces are provided at positions described over the interface between the layers, and an excavation is provided at the edge of the carrier.

Abstract: Cassette containing a recording carrier in tape form, and including means for transporting the recording carrier tape along an information transfer member forming part of the means for reading and/or writing and/or erasing the recording carrier tape. The cassette has an enclosure of hermetically sealed construction, and is filled with an inert low pressure gas which does not react chemically with the surface of the tape or with the surface of the tape guide means, if such means exists, such as hydrogen or helium gas at a pressure below 0.05 MPa.

Abstract: Device for guiding an information carrier which is in tape form and moves between two reels. The device is situated in the path of tape transport between the two reels and embodied as a slidable guide member along which the tape is moved with a certain tape tension. The guide member is a non-rotatable sliding member adapted to oscillate in a direction at right angles to the local direction of movement of the tape, with a maximum acceleration which is at least a few times greater than the transverse component of the tape tension divided by the mass of that part of the tape which is affected by the sliding member.

Abstract: A case provided with an information carrier consisting of a tape, one side of which has a structure carrying optically readable information as well as an apparatus for writing, reading or erasing such information. In the dustproof case containing a tape having on one side a structure carrying optically readable information, the tape is accomodated on two reels. The case is provided with one window through which a part of the tape between the reels is visible and with pressing means for urging that visible part of the tape against the window. This pressing means may be a wheel and the window may have the shape of a cylindrical lens.

Abstract: Method for reproducing relief structures onto a substrate, whereby between a die surface comprising holes or protuberances corresponding to the negative shape of the relief to be reproduced, and a substrate a hardenable liquid is deposited. After depositing the die surface and the substrate are at least locally forced together whereby the respective section of the die surface does not move in relation to the substrate in any other direction than perpendicular to the contact surface. During the following hardening of said liquid there is no mutual movement between the die surface and the substrate both of which remain forced together with a pressure which is smaller than the pressure during the initial pressing stage. The substrate and the die surface are separated after the liquid is hardened.

Abstract: A medium for recording optically readable information, comprising a transparent substrate layer, a semi reflective recording layer of a material which can melt, atomize or evaporate under the influence of light, and a separating layer is disclosed. Holes are put into the separating layer with a regular pattern with the holes extending through the complete thickness of the layer.

Abstract: An apparatus for controlling the monoplanar motion of an object, more in particular a tape containing optically readable information, comprising two opposite clamping means on either side of the object. The object as well as at least one of the clamping means are accommodated within a dustproof case. One of the clamping means can be moved relative to the other by generating an (electro)magnetic field outside the case.

Abstract: A case provided with a conveying means for conveying tape-like information carrier as well as an apparatus for writing, reading or erasing information to be utilized in combination with such a case. A case for an information carrying tape, provided with two reels. No rotary parts extend through the wall. Each reel is rotatably mounted and can also move axially between a position in which it is locked and one in which it can rotate. If no (electro)magnetic field is present each reel is in the locked position. If outside the case a rotary (electro)magnetic field is generated which penetrates to a reel, this reel is moved from the locked into the unlocked position and subsequently rotated by the field.

Abstract: A transmission apparatus utilizes the shear resistance in the laminar flow of hydraulic fluid in the active gap between the opposing surfaces of the transmission plates in order to control the transmission of torque. The apparatus comprises at least one plate having a perforated active surface and provided with at least one flowpath away from the active surface, the flowpath connecting the perforations with the non-active space around the perforated plate, and at least one corresponding plate having a non-perforated active surface spaced apart from the active surface of the perforated plate by an active gap. The active gap, the perforations, and the flowpath are arranged and dimensioned such that the resistance to radial flow in the gap is several times the resistance to flow through the perforations and the flowpath in order to create and maintain in the gap at a tangential laminar flow without an effective radial flow component.