Abstract: The present invention provides for improved brightness and reduced power consumption in transflective displays operating in transmissive mode. The invention is based on the inclusion of a depolarizing means (206) between the transflector (201) and the rear stack polarizer (202). The depolarizer (206) is arranged to selectively depolarize light originating from the backlight (203) and reflected by the transflector (201), without substantially affecting the light that is transmitted through the transflector. Thereby part of the reflected light is transmitted back through the rear stack polarizer (202) and can be recycled in the backlight (203). The invention is applicable to any transflective display having a transflector (201) that changes polarization of light originating from the backlight (203) upon reflection back towards the backlight (202).

Abstract: This invention relates to a normally white super-twist nematic liquid crystal display device for multiplex operation, comprising a liquid crystal cell essentially comprising a liquid crystal layer (2), being sandwiched between a front and a rear substrate (3, 4), an at least partly reflective film (5, 13, 14, 15), arranged in proximity to said rear substrate (4), and a front optical stack, arranged on a viewer's side of the front substrate, the stack comprising one or more optical films, wherein the front optical stack consists solely of a polarizer (7) and an optional light scattering film (6).

Abstract: This invention relates to a liquid crystal display device, comprising at least one retardation film (4), a nematic liquid crystal layer (5), and a light reflecting RGB patterned cholesteric colour filter (6), for reflecting either essentially left-circular or right-circular polarised light, being characterised in that said liquid crystal layer (5) is a super twisted nematic liquid crystal layer having a twist angle in the interval 180-270 degrees, and in that the summed retardation R of the retardation film or retardation films and the liquid crystal layer is equal to approximately R=(3+2n)?/4, where n=0,1,2,3.

Abstract: This invention relates to a liquid crystal display device, comprising at least one retardation film (4), a nematic liquid crystal layer (5), and a light reflecting RGB patterned cholesteric color filter (6), for reflecting either essentially left-circular or right-circular polarized light, being characterized in that said liquid crystal layer (5) is a super twisted nematic liquid crystal layer having a twist angle in the interval 180-270 degrees, and in that the summed retardation R of the retardation film or retardation films and the liquid crystal layer is equal to approximately R=(3+2n)&lgr;/4, where n=0,1,2,3 . . . .

Abstract: This invention relates to a liquid crystal display device, comprising at least one retardation film (4), a nematic liquid crystal layer (5), and a light reflecting RGB patterned cholesteric color filter (6), for reflecting either essentially left-circular or right-circular polarized light, being characterized in that said liquid crystal layer (5) is a super twisted nematic liquid crystal layer having a twist angle in the interval 180-270 degrees, and in that the summed retardation R of the retardation film or retardation films and the liquid crystal layer is equal to approximately R=(3+2n)&lgr;/4, where n=0,1,2,3 . . . .

Abstract: Manufacture of a display device for a touch panel display, for example, an LCD (20) is simplified by attaching parts of the display panel, for example, a light-scattering film (27) and a polarizer (28) to a substrate (11) of the touch panel (10).

Abstract: In a touch panel display, a substrate (11) of the touch panel (10) or the touch panel itself is used as an optical guide for lighting a reflective display (20).

Abstract: In a touch panel display, the touch panel (10) is inclined with respect to the (reflective) display (20) to prevent degradation of the image by spurious reflections.

Abstract: A plasma-addressed liquid crystal color display device comprising a layer of liquid crystal material, data electrodes coupled to the liquid crystal layer and adapted to receive data voltages for activating pixels of the liquid crystal layer, and a plurality of ionizable-gas-filled plasma channels extending generally transverse to the data electrodes for selectively switching on said liquid crystal pixels. The plasma channels are sealed off by a thin dielectric sheet. To reduce the magnitude of the data voltages needed to activate the device, the LC layers are given compositions such that a much higher fraction of the applied data voltages appears across the liquid crystal layer thereby allowing a smaller data voltage to be used to obtain the same effect on the liquid crystal pixels.

Abstract: The invention relates to a color filter layer of a cholesterically ordered material, in which the axis of the molecular helix is directed perpendicularly to said layer. According to the invention, the color filter layer comprises at least one dye which is able to absorb undesired colors caused by color shifts. A correct choice of the bandwidth of the primary colors of the color filter layer and the dyes significantly alleviates the problem of undesired color shift. The invention also relates to a liquid crystal color display device of the reflective type, which is provided with such a color filter layer.

Abstract: The invention provides active-matrix display devices with non-linear two-pole switching elements such as MIMs or three-pole switching elements such as TFTs having a smaller difference in charge current at a different image content by using a suitable. ##EQU1## This leads to less burn-in of the image to be displayed. Moreover, a satisfactory transmission characteristic is obtained at a higher value of .epsilon..sub..perp.. For TFTs it is then possible to use smaller auxiliary capacitances due to the higher values of (.epsilon..sub..perp.). The latter aspect may in turn be utilized to realise a larger aperture.

Abstract: Nematic liquid crystal display device, in which the isocontrast curve has obtained a more symmetrical shape by combining two and four sub-pixels with twist angles which are smaller than 90 degrees, at which the sub-pixels are obtained by providing different orientation directions (11) in an orienting layer (8) by means of linearly polarized light. If a cholesteric nematic liquid crystal material is used, a sub-pixel may have a twist angle of more than 90 degrees, while pairs of sub-pixels then have twist angles of opposite twist sense, at which the sum of the absolute values of the twist angles is smaller than 180 degrees.

Abstract: The Application relates to an illumination system comprising a fluorescent lamp and a broadband, cholesteric polarizer. Such a polarizer contains a layer of a polymeric material having a cholesteric order, which material is ordered in such a way that the axis of the molecular helix extends at right angles to the layer. The broadband character of the polarizer is obtained by causing the pitch of the molecular helix to increase from a minimum value at a first surface of the cholesteric layer to a maximum value at the second surface of the layer. In accordance with the invention, the polarizer should be positioned in the illumination system in such a manner that the cholesteric layer is directed towards the fluorescent lamp with its first surface. In addition, the value of the product p.sub.max.n.sub.e of the maximum value of the pitch in the cholesteric layer p.sub.max and of the extraordinary refractive index n.sub.e must range between 0.61 micron and 0.76 micron.

Abstract: In a liquid crystal display device the number of grey levels is increased by means of a compensation foil comprising a layer having a cholesteric ordering with a helix pattern, in which the pitch of the helix is smaller than (0.26-0.31..DELTA.n) .mu.m, in which .DELTA.n is the optical anisotropy of the anisotropic layer. Moreover, the viewing angle dependence will be more symmetrical by patterning the cholesteric ordering.

Abstract: Optically active dopants of the formula ##STR1## wherein A represents an optically active group selected from 1,1'-binaphthyl-2,2'-diyl, --CHR.sup.1 --CHR.sup.2 -- or --CH(COOR.sub.3)--CH(COOR.sub.4)--; Z denotes a group --(CH.sub.2).sub.4 --, --O(CH.sub.2).sub.3 -- or the trans form of --OCH.sub.2 --CH.dbd.CH--; R is hydrogen, methyl, phenyl or cyclohexyl; R.sup.2 is methyl, phenyl or cyclohexyl; R.sup.3 and R.sup.4 denote alkyl; Y stands for --CO-- or --CH.sub.2 --; ring B represents 1,4-phenytene or trans-1,4-cyclohexylene; and R is hydrogen, alkyl, alkoxy or cyano,liquid crystalline mixtures which contain such dopants and their use for optical and electro-optical purposes.

Abstract: Optically active compounds of the formula ##STR1## wherein m stands for the number 1 and R.sup.2 is an unsubstituted or halogen-substituted alkyl or alkenyl group in which optionally one methylene group is replaced by oxygen and/or optionally one methylene group is replaced by an ester group --COO-- or --OOC--; or m stands for the number 0 or 1 and R.sup.2 denotes a group of the formula ##STR2## R.sup.1 and R.sup.3 each independently represent an alkyl or alkenyl group in which optionally one methylene group is replaced by oxygen; Z.sup.1, Z.sup.2 and Z.sup.3 each independently are a single covalent bond, --CH.sub.2 O--, --OCH.sub.2 --, --CH.sub.2 CH.sub.2 --, --COO-- or --OOC--; n stands for the number 0 or 1; rings A.sup.1 and A.sup.2 each independently are unsubstituted or halogen, cyano and/or methyl-substituted 1,4-phenylene in which optionally 1 CH group or 2 CH groups is/are replaced by nitrogen; and C.sup.* denotes a chiral carbon atom; with the proviso that simultaneously R.sup.

Abstract: Compounds of the formula ##STR1## wherein n stands for the number 0 or 1; R.sup.1 denotes a group R.sup.3 or R.sup.3 --A.sup.3 --Z.sup.2 -- and R.sup.2 denotes a group R.sup.4 or R.sup.4 --A.sup.4 --Z.sup.3 --; ring A.sup.1 is unsubstituted or halogen-, cyano- and/or methylsubstituted 1,4-phenylene in which optionally 1 CH group or 2 CH groups is/are replaced by nitrogen; A.sup.3 A.sup.4 and ring A.sup.2 each independently represent unsubstituted or halogen-, cyano- and/or methyl- -substituted 1,4-phenylene in which optionally 1 CH group or 2 CH groups is/are replaced by nitrogen or trans-1,4-cyclohexylene, trans-1,3-dioxane-2,5-diyl, 1-cyano-trans-1,4-cyclohexylene, bicyclo[2.2.2]octane- -1,4-diyl, naphthalene-2,6-diyl, tetralin-2,6-diyl or trans-decalin-2,6- diyl; Z.sup.1, Z.sup.2 and Z.sup.3 each independently are a single covalent bond, --COO--, --OOC--, --CH.sub.2 O--, --OCH.sub.2 --, --CH.sub.2 CH.sub.2 --, --C.vertline.C--, --(CH.sub.2).sub.3 O--, --O(CH.sub.2).sub.3 --, --(CH.sub.2).sub.

Abstract: Optically active compounds of the formula ##STR1## wherein R.sup.1 and R.sup.2 each are alkyl with at least 2 carbon atoms; A.sup.1, A.sup.2 and A.sup.3 each are unsubstituted, cyano-, halogen- or methyl-substituted 1,4-phenylene, optionally having one or two CH groups replaced by nitrogen, unsubstituted, cyano- or methyl-substituted trans-1,4-cyclohexylene, the cyclohexylene optionally having one or two CH.sub.2 groups replaced by oxygen; Z.sup.1 and Z.sup.2 each are a single covalent bond, --COO--, --OOC--, --CH.sub.2 CH.sub.2 --, --OCH.sub.2 --, --CH.sub.2 O--, --C.tbd.C--, --COS-- or --SOC--; m stands for the number 0 or 1; n is an integer of 0 to 4; X is oxygen or a methylene group; and each C* represents a chiral carbon atom, one of the chiral carbon atoms has the R-configuration while the other has the S-configuration.The compounds are used in liquid crystalline mixtures to compensate the temperature dependence of the threshold potential of liquid crystal cells.

Abstract: Optically active compounds of the formula ##STR1## wherein m stands for the number 1 and R.sup.2 is an unsubstituted or halogen-substituted alkyl or alkenyl group in which optionally one methylene group is replaced by oxygen and/or optionally one methylene group is replaced by an ester group --COO-- or --OOC--; or m stands for the number 0 or 1 and R.sup.2 denotes a group of the formula ##STR2## R.sup.1 and R.sup.3 each independently represent an alkyl or alkenyl group in which optionally one methylene group is replaced by oxygen; Z.sup.1, Z.sup.2 and Z.sup.3 each independently are a single covalent bond, --CH.sub.2 O--, --OCH.sub.2 --, --CH.sub.2 CH.sub.2 --, --COO-- or --OOC--; n stands for the number 0 or 1; rings A.sup.1 an A.sup.2 each independently are unsubstituted or halogen, cyano and/or methyl-substituted 1,4-phenylene in which optionally 1 CH group or 2 CH groups is/are replaced by nitrogen; and C* denotes a chiral carbon atom; with the proviso that simultaneously R.sup.

Abstract: Compounds of the formula ##STR1## wherein R.sup.1 is alkyl or alkenyl; Z.sup.1 denotes a single covalent bond or --CH.sub.2 CH.sub.2 --; ring A represents unsubstituted or halogen- and/or methyl-substituted 1,4-phenylene; Z.sup.2 denotes a single covalent bond, oxygen or --CH.sub.2 O--; and R.sup.2 is an unsubstituted or halogen-substituted alkyl or alkenyl group,their preparation as well as liquid crystalline mixtures and their use for electro-optical purposes.