摘要:
A dark field projection display comprises a spatial light modulator (7) and a light source in the form of a lamp (1) and a reflector (2). Light from the light source (1, 2) passes to a plurality of optical sub-systems, such as a split Fresnel lens (3) with the lens portions (3a, 3b) being relatively displaced. The sub-systems (3) form a spatial distribution of images of the source (1, 2) with the relative positions of the source images being different from the relative positions of input apertures of the sub-systems (3a, 3b). A plurality of reflectors, such as mirrored corner cubes and microlenses (4) arranged in a vertical array, receives the source images and forms overlapping images (8) at the modulator (7).
摘要:
A method is provided of making a cell wall (1 to 5) of a liquid crystal spatial light modulator (1 to 11). The cell wall comprises a substrate (1) above which is formed a polariser (3) made of a polymer with conjugated double bonds. An alignment layer (5) is formed above the polariser (3) relative to the substrate (1). The conditions during manufacture are such that the performance of the polariser (3) is not excessively degraded. It is thus possible to provide a liquid crystal device containing an internal polariser and having acceptable performance.
摘要:
A diffractive spatial light modulator comprises an array of pixels (40) which can be actively or passively addressed. Each pixel comprises a material such as a ferroelectric liquid crystal addressed on one side by interdigitated elongate first and second electrodes (3a, 3b). The interdigitated electrodes are connected to an address signal generator, such as a strobe signal generator (43) and a data signal generator (41, 42). The address signal generator supplies signals which allow each pixel to be switched to any one of a non-diffractive state and a plurality of different diffractive states of different diffraction efficiencies. This may be achieved by varying the diffraction grating mark/space ratios. Alternatively or additionally, the individual interdigitated electrodes may be controlled so as to allow non-periodic gratings to be written at each pixel.
摘要:
A method and system adaptively substitutes a single dialing button sequence for a selected action in a voice menu of a telephone system. A shortcut message in the voice menu prompts a caller to select a shortcut button to acheive a shortcut action. The system then accumulates counts related to frequencies of occurrence of a plurality of actions prompted by the voice menu. The system then ranks the plurality of actions by their respective accumulated counts and determines if any one of the plurality of actions has an accumulated count greater than an accumulated count of the shortcut action. If it does, then the system causes the substitution the one of the plurality of actions and a corresponding message for the shortcut action and the shortcut message in the voice menu.
摘要:
A cholesteric film 1 is formed into an optical device comprising a plurality of layers 17, 18 and 19. The cholesteric film is initially placed in a first predetermined state, for instance heating to a first predetermined temperature, and is then irradiated with narrow band UV radiation. The properties of an upper layer 17 of the film are fixed, for instance for reflecting normally incident infrared radiation of a particular handedness. This process is repeated for different wavelengths of UV fixing radiation so as to penetrate to different depths from the surface 2 of the film 1 in order to form the layers 17, 18 and 19. This method may be used to produce a filter of reduced sensitivity to angle of incidence. In addition to the infrared reflecting layer 17, red and green reflecting layers 18 and 19 are provided. For normally incident radiation, the red and green layers 18 and 19 reflect red and green parts R and G, whereas the blue part B of the spectrum is transmitted. For off-axis illumination or viewing, the red part R is reflected by the infrared layer 17 and the green part G is reflected by the red layer 18. The birefringence of the layers 17 and 18 reverses the direction of circular polarisation of the blue part B, which thus passes through the green layer 19.
摘要:
An active matrix liquid crystal display (40) includes a data line driver circuit (44) and a scan line driver circuit (42). The circuits are controlled so that a data input signal is sampled and stored to produce data signals for a first group of the control elements along the row in a first line subperiod and the stored data signals are applied to the first group of control elements in a second line subperiod, and so that the data input signal is sampled and stored to produce data signals for a second group of control elements along the row in the second line subperiod and the stored data signals are applied to the second group of control elements in a subsequent line subperiod. Such an arrangement requires only a single data memory for each data line.
摘要:
A liquid crystal display comprises, in order from the viewing side, a first glass substrate 10 carrying an electrode 12, a dichroic liquid crystal layer 16 provided with suitable alignment layers 14, 18, a half wave retarding layer 30, a quarter wave retarding layer 20, a reflector 24 and a second glass substrate 28 carrying an electrode 26. In use, in one of its states, the dichroic liquid crystal layer 16 absorbs a component of the light incident thereon, the transmitted component being plane polarised. The polarised light is incident upon the retarding layer 20 which converts the plane polarised light to circularly polarised light, this light being reflected and converted back to plane polarised light polarised in a direction perpendicular to the original plane of polarisation on returning through the retarding layer 20. Such polarised light is absorbed by the dichroic dye, no light being transmitted by the cell towards the viewer. The presence of the layer 30 improves the achromaticity of and light absorption in the dark state. In another state, the dichroic dye does not absorb, and hence does not polarise, the light, the cell then transmitting light to the viewer.
摘要:
A cholesteric film 1 is formed into an optical device comprising a plurality of layers 17, 18 and 19. The cholesteric film is initially placed in a first predetermined state, for instance heating to a first predetermined temperature, and is then irradiated with narrow band UV radiation. The properties of an upper layer 17 of the film are fixed, for instance for reflecting normally incident infrared radiation of a particular handedness. This process is repeated for different wavelengths of UV fixing radiation so as to penetrate to different depths from the surface 2 of the film 1 in order to form the layers 17, 18 and 19. This method may be used to produce a filter of reduced sensitivity to angle of incidence. In addition to the infrared reflecting layer 17, red and green reflecting layers 18 and 19 are provided. For normally incident radiation, the red and green layers 18 and 19 reflect red and green parts R and G, whereas the blue part B of the spectrum is transmitted. For off-axis illumination or viewing, the red part R is reflected by the infrared layer 17 and the green part G is reflected by the red layer 18. The birefringence of the layers 17 and 18 reverses the direction of circular polarisation of the blue part B, which thus passes through the green layer 19.
摘要:
A ferroelectric liquid crystal device, such as a display panel, has a plurality of pixels arranged as rows and columns in a passive matrix arrangement. Each pixel has a plurality of switching thresholds, for instance by having different regions (7, 8) of different thicknesses, so as to provide a plurality of grey levels. A voltage waveform is applied to each pixel for switching it to a desired grey level. A blanking pulse of a first polarity is applied to reset the pixel to a reset grey level. This is followed by a compensating pulse (20) of polarity opposite the first polarity, after which a waveform for selecting the desired grey level is provided. The effect of the compensating pulse (20) is to reduce the effect of τmin shift so as to provide a relatively wide driving window (13) to allow more reliable selection of an intermediate grey level.