Abstract: An optical device comprises an input polarizer 4, a patterned retarder 5 and an output polarizer 12. The retarder 5 has regions 8 and 9, at least one of which alters the polarization of light from the input polarizer 4. The output polarizer 7 has a transmission axis 12 such that light passing through the regions 8 and 9 of the retarder 5 and through the output polarizer 7 is matched in amplitude, phase and polarization. Such a device may be used as a switchable parallax barrier with an LCD 2 to provide a display which is switchable between an autostereoscopic 3D mode and a 2D mode with the 2D mode having more uniform intensity across the display.

Abstract: A display is switchable between a first display mode with a first viewing angle range, a second display mode having a second viewing angle range smaller than the first viewing angle range and a multiple view directional display mode. The display includes an image display layer and a control element that is switchable between a first state in which it cooperates with the image display layer to provide the first display mode, a second state in which it cooperates with the image display layer to provide the second display mode, and a third state in which it cooperates with the image display layer to provide the multiple view directional display mode.

Abstract: An autostereoscopic display comprises a pixellated transflective spatial light modulator which is arranged to provide a visual indication to an observer of the amount of crosstalk caused by reflection of ambient illumination. The display comprises a rear parallax barrier between a backlight and the modulator. Part of the barrier is formed as a screen blocking transmitted light from a first region of the modulator so that the pixels in this region are visible only by reflection of ambient illumination. In a second region, the pixels are illuminated with both transmitted and reflected light. A controller sets the pixels of the first region to maximum intensity and the pixels of the second region to a fraction of the maximum intensity. The fraction corresponds, for example, to a maximum amount of crosstalk which is permissible for autostereoscopic viewing.

Abstract: Bandwidth use between an access provider system (14) and a user computer (10) is adapted to an amount of subscription quotum that has been used by a subscriber. Quotum use information is representative of an amount of data that has been exchanged between the user computer (10) and an access provider system (14) since a predetermined time point. A request is received for retrieving media information from the network (16) and for rendering that media information at the user computer (10). In response to the request a selection is made between a plurality of versions of the requested media information, dependent on the quotum use information. Different versions require respective different data rates for transmission from the access provider system (14) to the user computer (10). The more quotum has been used, the lower the data rate of the selected version.

Abstract: A spatial light modulator comprises: a first substrate (25); a second substrate (26); a layer of electrooptic material disposed between the first substrate and the second substrate. A first electrode arrangement (27) is disposed over the first substrate (25); and a second electrode arrangement (35) is disposed over the second substrate (26). The first electrode arrangement (27) comprises first and second electrode layers (28,29) disposed over the first substrate, with the spacing between the first electrode layer (28) and the first substrate (25) being different to the spacing between the second electrode (29) layer and the first substrate (25). The first electrode layer (28) and the second electrode arrangement (35) are configured so as to co-operate, in use, to define a plurality of first addressable regions in the electrooptic material.

Abstract: The invention relates to ureido or carbamate derivatives of crown ethers and of silicon of formula: These derivatives can be grafted to silica gel for the purpose of obtaining supports for the chromatographic separation of cations or of molecules comprising amine functional groups, such as amino acids.

Abstract: A polarization rotator is provided for rotating the polarization direction of linearly polarized light by any arbitrary angle other than 90°. The device comprises a layer of liquid crystal material disposed between alignment surfaces. In one mode, a 90° twist is induced in the liquid crystal director. An expression is provided for relating the retardation of the layer to the amount of polarization rotation and the angle between the polarization direction of incident light and the alignment direction at the input side of the liquid crystal layer.

Abstract: The invention relates to ureido or carbamate derivatives of crown ethers and of silicon of formula: These derivatives can be grafted to silica gel for the purpose of obtaining supports for the chromatographic separation of cations or of molecules comprising amine functional groups, such as amino acids.

Abstract: The invention relates to a pivot bearing for a vehicle having a base body for connecting wheel guiding elements to a wheel. The base body is composed of a planar piece of sheet metal to which a flange plate is assigned. The flange plate is connected to the base body in a frictionally locking fashion.

Abstract: A broadband optical retardation device, such as may be used for polarisation encoding of display information or in diffractive optical systems, includes a patterned uniform half wave plate retarder in combination with a non-patterned uniform quarter wave plate retarder having an optic axis oriented at 90° to the xz plane. The patterned retarder consists of alternating first and second regions having first and second optic axes at different orientations to a reference axis, for example at +22.5° and −22.5° to the xz plane. Considering light of wavelength &lgr;° incident on the retarder and linearly polarised in the xy plane, such light is differently polarised by the regions, and the light output by the device includes regions in which the light is right circularly polarised and regions in which the light is left circularly polarised.

Abstract: The invention relates to a method for electrochemically depositing a catalyst, especially a noble metal, from a precursor layer which is present on a membrane and in which the catalyst material is present in the form of salts that are soluble in the membrane material. According to the method, the membrane is surrounded by an atmosphere containing water vapour during the deposition process, this atmosphere ensuring the stability and ionic conductibility of the membrane. In contrast to methods used up until now, this prevents the soluble catalyst salt from being dissolved out the precursor layer. The method can be carried out in a simple device comprising a sealable vessel which can be advantageously tempered, a holder for receiving a membrane/precursor unit, a gas supply and electrical contacts.

Abstract: A polarisation rotator is provided for rotating the polarisation direction of linearly polarised light by any arbitrary angle other than 90°. The device comprises a layer of liquid crystal material disposed between alignment surfaces. In one mode, a 90° twist is induced in the liquid crystal director. An expression is provided for relating the retardation of the layer to the amount of polarisation rotation and the angle between the polarisation direction of incident light and the alignment direction at the input side of the liquid crystal layer.

Abstract: An autostereoscopic display comprises a pixellated transflective spatial light modulator which is arranged to provide a visual indication to an observer of the amount of crosstalk caused by reflection of ambient illumination. The display comprises a rear parallax barrier between a backlight and the modulator. Part of the barrier is formed as a screen blocking transmitted light from a first region of the modulator so that the pixels in this region are visible only by reflection of ambient illumination. In a second region, the pixels are illuminated with both transmitted and reflected light. A controller sets the pixels of the first region to maximum intensity and the pixels of the second region to a fraction of the maximum intensity. The fraction corresponds, for example, to a maximum amount of crosstalk which is permissible for autostereoscopic viewing.

Abstract: A method of making a patterned retarder of the present invention includes the steps of providing an alignment layer rubbing the alignment layer in a first rubbing direction, masking with a mask at least one first region of the alignment layer, to reveal at least one second region of the alignment layer, rubbing the at least one second region through the mask in a second rubbing direction different from the first rubbing direction, removing the mask, disposing on the alignment layer a layer of birefringent material whose optic axis is aligned by the alignment layer, and fixing the optic axis of the birefringent layer.

Abstract: A parallax barrier includes a polarization modifying layer having aperture regions, for supplying light of a second polarization when receiving light of a first polarization, separated by barrier regions, for supplying light of a third polarization different from the second polarization when receiving light of the first polarization, and a polarizer selectively operable in a first mode and a second mode. At least one of the aperture regions and the barrier regions alters the polarization of light passing therethrough. The polarizer passes light of the second polarization and blocks light of the third polarization in the first mode and passes light of the third polarization in the second mode.

Abstract: A parallax barrier includes a polarisation modifying layer having aperture regions, for supplying light of a second polarisation when receiving light of a first polarisation, separated by barrier regions, for supplying light of a third polarisation different from the second polarisation when receiving light of the first polarisation, and a polariser selectively operable in a first mode and a second mode. At least one of the aperture regions and the barrier regions alters the polarisation of light passing therethrough. The polariser passes light of the second polarisation and blocks light of the third polarisation in the first mode and passes light of the third polarisation in the second mode.

Abstract: A passive polarisation modulating optical element comprises a layer of birefringent material. The layer has substantially fixed birefringence and comprises retarder regions forming a regular pattern, for instance to act as a parallax barrier for a 3D display. The retarders have optic axes aligned in different directions from each other. The element may be associated with a polariser, for instance an output polariser of a liquid crystal device, with the polarising direction of the polariser being parallel to the optic axis of the retarders. Thus, the retarders have no effect on the intensity of light passing through the element whereas the retarders act as half waveplates and rotate the polarisation vector of light passing therethrough, for instance by 90.degree..

Abstract: A parallax barrier includes a polarisation modifying layer having aperture regions, for supplying light of a second polarisation when receiving light of a first polarisation, separated by barrier regions, for supplying light of a third polarisation different from the second polarisation when receiving light of the first polarisation, and a polariser selectively operable in a first mode and a second mode. At least one of the aperture regions and the barrier regions alters the polarisation of light passing therethrough. The polariser passes light of the second polarisation and blocks light of the third polarisation in the first mode and passes light of the third polarisation in the second mode.

Abstract: Connection control apparatus is provided for use in an ATM network to control ABR connections provided by the network, each such ABR connection having an agreed minimum transmission rate which it is permitted to exceed when there is spare capacity in the network. The apparatus includes: congestion detection circuitry (32, 33) for determining the end-to-end delay experienced by ATM cells of each ABR connection as they pass through the network; and a rate control circuit (30) connected to the said congestion detection circuitry for detecting, based on the determined end-to-end delay, when one of the ABR channels is congested. When congestion in one of the ABR channels is detected the rate control circuit imposes on the ABR connection concerned a maximum transmission rate that is higher than and dependent upon the said agreed minimum transmission rate for the connection concerned.

Abstract: A circuit for measuring current in a power MOS transistor (M0) comprises second (M1) and third (M2) transistors in series of the same type and same technology as, but having a smaller surface than, the power transistor and arranged in parallel on the latter. The two series transistors have their gates connected to the gate of the power transistor. The current in transistor (M2) which is connected to the reference electrode of the power transistor is measured.