Abstract:
A high-contrast electro-optic liquid crystal camera iris (10) provides angle independent transmission for uniform gray shades. The liquid crystal iris comprises a combination of first and second liquid crystal devices (12, 14) arranged in optical series and positioned between optical polarizers (46, 48). The director field (18) of the second liquid crystal device is a mirror image of the director field (16) of the first liquid crystal device, and the first and second liquid crystal devices are placed together so that the azimuthal directions (42) of the surface-contacting directors (18c, 22c) are in parallel alignment at the adjoining or confronting surfaces of the substrates (242, 321) of the first and second liquid crystal devices. The liquid crystal iris provides, therefore, less angular variation of intermediate transmittances compared with that provided by prior art liquid crystal irises.
Abstract:
Self-compensating, quasi-homeotropic liquid crystal devices (100, 200, 300, 400) overcome the contrast reducing effects of smaller pretilt angles. The devices exhibit extremely high contrast ratio but at the same time suppress fringe field-induced disclination lines in high pixel density and small pixel size quasi-homeotropic displays. The surface pretilt (520, 540) and cell twist (570) angles are set at values that, in combination, contribute to establishing a cuspate singularity in the contrast ratio for normally incident light in response to a drive signal switching the liquid crystal device to the OFF director field state that provides nearly 0% optical efficiency. The OFF director field state corresponds to a subthreshold drive level that provides for the liquid crystal device self-compensation for in plane optical retardation. Setting the cell gap ("d") to provide substantially 100% optical efficiency in response to a value of the drive signal switching the liquid crystal device to the ON director field state achieves optimal dynamic range for the liquid crystal device.
Abstract:
An electronic (e.g., LCD) projector (50) combines multiple projection lens assemblies (100R, 100B, 100G) with equal color component optical path lengths (52B) to provide improved display images and a compact arrangement. In one implementation, the projector (50) includes a successive pair of angled dichroic mirrors (70, 78) that fold the red and blue color components of light in opposed directions. The green color component of light (52G) passes through the dichroic mirrors (70, 78) toward a pixelated electronic light modulator, such as a liquid crystal display, and an associated projection lens assembly. The red and blue color components of light (52R, 52B) are each folded again to propagate parallel with the green color component (52G) toward a pixelated electronic light modulator, such as a liquid crystal display, and an associated projection lens assembly. The separate projection lens assemblies (100R, 100B, 100G) are arranged in a non-linear, close-packed arrangement to receive the color components of light (52R, 52B, 52G).
Abstract:
A simple, reliable and cost-effective super-twisted nematic liquid crystal display is disclosed. The liquid crystal display is suitable for application in all portable electronic devices due to the reliable and simple design employing a thin crystal film polarizer and is particularly suitable for outdoor display applications due to its increased environmental robustness. The thin crystal film polarizer also increases the viewing characteristics of the liquid crystal display and provides additional advantages. The disclosed liquid crystal display includes a front and rear polarizer and a super-twisted nematic liquid crystal layer, wherein the liquid crystal layer has a twist angle from about 230° to about 250°. The front and rear transmission axes of the polarizers are angularly displaced by about 70° to about 86° relative to each other.
Abstract:
The invention relates to a liquid crystal display device (1) with a negative display when no current is supplied. Said device comprises a liquid crystal layer that is built into an active zone (2) between substrates, the exterior of each of said substrates being covered by pole filters that are aligned in an arrangement for the currentless negative display. The interior of said substrates is provided with segments (2.2) of surface electrodes that are separated from one another by means of electrically insulating dividing lines (5), said segments being connected to connection lines that lead to the exterior. Masking is provided on the interior of the substrate for areas that would otherwise remain bright during retrace blanking. The invention provides an advantageous construction and display quality, as the periphery of the active zone (2) is encompassed by adhesive strips (4), which appear black, between the substrates, and the masking, at least in bright areas that would otherwise be visible from a conventional viewing distance during retrace blanking, is produced by means of additional adhesive strips (4').
Abstract:
Die Erfindung bezieht sich auf eine im spannungslosen Zustand helle Flüssigkristallanzeigevorrichtung (1) mit einer in einer aktiven Zone (2) zwischen Substraten eingebrachten Flüssigkristallschicht, wobei die Substrate außen jeweils mit in einer Anordnung für die spannungslose Hellanzeige ausgerichteten Polfiltern abgedeckt sind und auf ihrer Innenseite mit elektrisch isolierenden Trennlinien (5) voneinander getrennte Segmente (2.2) von Flächenelektroden tragen, die mit nach außen führenden Anschlussleitungen verbunden sind, und wobei auf der Substratinnenseite eine Maskierung für bei Dunkelsteuerung ansonsten hell bleibende Bereiche vorgesehen ist. Vorteile für den Aufbau und die Qualität der Anzeige ergeben sich dadurch, dass die aktive Zone (2) umfangsseitig mit schwarz erscheinenden Kleberstreifen (4) zwischen den Substraten umschlossen ist und dass die Maskierung zumindest in ansonsten aus üblichem Betrachtungsabstand bei Dunkelsteuerung deutlich in Erscheinung tretenden Hellbereichen mittels weiterer Kleberstreifen (4') hergestellt ist.
Abstract:
A twisted type nematic liquid crystal display (LCD) device (30) having a liquid crystal layer (34) characterized as a polarization rotator below an optical threshold voltage, a half-wavelength plate at approximately a saturation voltage, and a transparent layer above the saturation voltage. The twist angle of the liquid crystal layer ranges from 0 DEG to 360 DEG . The twist angle of the liquid crystal layer preferably is between 46 DEG -89 DEG , and most preferably is about 55 DEG . The product of the birefringence of the liquid crystal and the thickness of the liquid crystal layer ( DELTA nd) is in the range of 0.35-0.70 mu m, and preferably about 0.52 mu m for the 55 DEG twist. One polarizing layer (42) is applied to the liquid crystal device with the polarization direction either parallel or perpendicular to the immediately neighboring liquid crystal director. Further, the performance of the LCD is dependent upon the parameters of the liquid crystal material, such as the elastic constants.
Abstract:
An automatic-darkening filter 10, 10' that comprises a first polarizer 14, a second polarizer 18, a first liquid-crystal cell 16, and a sensor 64. The first polarizer 14 has a first polarization direction, and the second polarizer 18 has a second polarization direction. The liquid crystal cell 16 is disposed between the first and second polarizers 14, 18 and contains first and second optically-transparent, flexible, glass layers 40 and 42 with the liquid crystal layer 48 being located between these layers. The sensor 64 detects incident light and causes a signal to be sent, which causes molecular rotation within the liquid crystal layer. The inventive automatic-darkening filter is beneficial in that overall product weight can be reduced and the view field can be increased.
Abstract:
A protective automatic darkening filter construction 10 includes two low twist liquid crystal cells 26, 30 interspersed between a series of offset polarizers 24, 28, 32. The resulting construction provides improved homogeneity in the dark state as viewed by the user over a large viewing angle. By reducing variations in shade, visibility through the filter may be improved.