Abstract: The structure and construction of a bistable twisted nematic liquid crystal display with very long lifetime are disclosed. The two stable twist states in this display when no voltage is applied have almost infinite lifetimes and do not decay. These two stable twist states differ by a twist angle of 180°. New design conditions of this bistable twist structure are disclosed such that the contrast and the brightness are both optimized. This display can be operated in transmittive mode with two polarizes or in the reflective mode with one polarizer.

Abstract: A surface mode liquid crystal device, for example of the pi-cell type, comprises a layer nematic liquid crystal (10) disposed between alignment layers (4,9) and an electrode arrangement (3,8). The nematic liquid crystal has viscosity coefficients &eegr;1, &eegr;2 and &ggr;1, such that (&eegr;1-&eegr;2)/&ggr;1≧1.15 or (&eegr;1-&eegr;2)/&ggr;1≦0.9.

Abstract: An achromatic half wave plate includes a first twisted nematic liquid crystal layer, a second twisted nematic liquid crystal layer, and a uniaxial half wave plate between the first twisted nematic liquid crystal layer and the second twisted nematic liquid crystal layer. In one embodiment the first twisted nematic liquid crystal layer and the second twisted nematic liquid crystal layer have an identical twist angle of 135 degrees. The optic axis at the entrance of the first twisted nematic liquid crystal layer is substantially orthogonal to the optic axis at the exit of the second twisted nematic liquid crystal layer.

Abstract: A liquid crystal display device comprises: a layer of a chiral liquid crystal material disposed between first and second substrates; and means for applying a voltage across the liquid crystal layer. A first region of the liquid crystal layer is an active region for display and a second region of the liquid crystal layer is a nucleation region for generating a desired liquid crystal state in the first region when a voltage is applied across the liquid crystal layer. The ratio of the thickness d of the liquid crystal layer to the pitch p of the liquid crystal material has a first value (d/p)A in the first region of the liquid crystal layer and has a second value (d/p)N different from the first value in the second region of the liquid crystal layer.

Abstract: The present invention provides the conditions for new bistable twisted nematic liquid crystal displays, in particular the necessary twist angles, liquid crystal retardation values, input and output polarizer angles, for both transmissive and reflective liquid crystal displays.

Abstract: In a liquid crystal display device comprising first and second substrates having first and second principal surfaces which are opposed to each other with a space left therebetween, first and second alignment layers are formed on the first and the second principal surfaces of the first and the second substrates. The first alignment layer is subjected to a first aligning treatment in a first aligning treatment direction while a second alignment layer is subjected to a second aligning treatment in a second aligning treatment direction which shifts from the first aligning treatment direction by a predetermined slight angle. Interposed between the first and the second alignment layers, a liquid crystal layer comprises a plurality of liquid crystal molecules each of which is twist aligned by a twist angle equal to the predetermined slight angle.

Abstract: A reflective liquid crystal display device includes: first and second substrates spaced apart and facing each other; a twisted nematic liquid crystal layer sandwiched between the two substrates, the liquid crystal layer having a twist angle and birefringence property &Dgr;n and having a thickness d; a retardation film disposed on the first substrate and opposite to the liquid crystal layer, the film converting a first linearly polarized light from above to a first circularly polarized light and converting a second circularly polarized light reflected from below to a second linearly polarized light; a linear polarizer disposed on the retardation film and opposite to the liquid crystal layer and converting the incident light to the first linearly polarized light; and a reflector disposed between the liquid crystal layer and the second substrate and reflecting light passed through the liquid crystal layer.

Abstract: The invention relates to TN and STN liquid-crystal displays and to the novel nematic liquid-crystal mixtures used therein, characterized in that they comprise one or more compounds of the formula I 1

Abstract: A reflection liquid crystal display device comprising only one polarization film, wherein the twist angle of a nematic liquid crystal ranges from 0° to 90°, the relationship between the difference between the indices of birefringence &Dgr;nLC, the thickness of the liquid crystal layer dLC, and the retardation of the phase plate RF is expressed by &Dgr;nLC.dLC=0.20 to 0.30 &mgr;m, RF-&Dgr;nLC.dLC=−0.20 to −0.

Abstract: The invention relates to dielectrically positive nematic liquid crystal compositions for active matrix displays with high voltage holding ratio and very low birefringence. The composition of the mixtures is given in claim 1. The compositions are particularly suited for reflective displays. The invention further relates to particular reflective displays with low optical retardation.

Abstract: A reflective liquid crystal display device includes: a liquid crystal layer in a cell; a polarizer disposed in front of the liquid crystal layer; a reflector disposed behind the liquid crystal layer; and a quarter-wave plate disposed between the liquid crystal layer and the reflector, the liquid crystal layer including a liquid crystal and a liquid crystalline polymer which are twisted in molecule alignment so as to have a twist angle X represented by X=(45°+90° n)±10° (n=0 or a positive integer).

Abstract: The invention pertains to a normally white super twisted nematic (NW-STN) display comprising a super twisted nematic (STN) display cell and a compensation layer, characterized in that the compensation layer is a twisted liquid crystalline polymer and has an optical retardation (OR) which is 10 to 50% of the OR of the display cell in the off-state, and wherein the absolute value of the twist angle of the compensation layer is between 150° and 10° and is at least 90° smaller that the absolute value of the twist angle of the STN display cell. Preferably, the compensation layer of the NW-STN display is temperature matched with the STN display cell.

Abstract: A twisted nematic liquid crystal-based electro-optic modulator with a twist angle between 0° and 90°, and preferably between 50° and 80° is provided. The modulator provides a relatively rapid switching time such as less than about 50 milliseconds, and provides relatively large extinction ratios, such as greater than −25 dB. Preferably the liquid crystal entrance director differs from the polarization direction by a beta angle of about 15°.

Abstract: A liquid crystal display device is disclosed, comprising a cholesteric liquid crystal layer which has an intrinsic helical pitch of approximately twice as large as a thickness of the liquid crystal layer and also has a bistable character capable of switching by an application of voltage, and further provided with at least one birefringent medium layer between a polarizer and a substrate. This construction of the liquid crystal display device results in a reduction of birefringent effects, whereby achieving a high contrast, satisfactory color purity, and other display characteristics such as a higher duty ratio operation and faster time response, suitable for displaying a large volume of information data.

Abstract: A generalized mixed twisted nematic/birefringent effect mode is presented for reflective liquid crystal displays with only one polarizer. This new MTB mode encompasses all previously published reflective nematic liquid crystal display modes and is clearly shown on the parameter space diagrams. The invention of how to obtain operating conditions of this generalized mixed mode display is discussed. For any given angle between the polarizer and the input director of the liquid crystal cell, a unique range of values of the twist angle and the retardation d&Dgr;n for efficient reflection and low dispersion is defined.

Abstract: A liquid crystal display device, includes: a first substrate, a second substrate, a liquid crystal layer interposed therebetween, and a plurality of pixel regions defined by a pair of electrodes for applying a voltage to the liquid crystal layer. Each of the plurality of pixel regions includes a reflection region and a transmission region, and the liquid crystal layer is made of a liquid crystal material having positive dielectric anisotropy. A first polarizing element is provided on the first substrate opposite to the liquid crystal layer; a second polarizing element is provided on the second substrate opposite to the liquid crystal layer; a first phase difference compensator is provided between the first polarizing element and the liquid crystal layer; and a second phase difference compensator is provided between the second polarizing element and the liquid crystal layer. A twist angle &thgr;t of the liquid crystal layer is in a range of 0° to 90°.

Abstract: An electrooptical system contains: (a) a twisted nematic liquid-crystal layer, with an input side and an output side, which is positioned between a first substrate and a second substrate, each of whose inside surface is provided with an electrode coating and an alignment layer thereon, the director of said liquid crystal layer having a parallel edge alignment and a twist angle of 0°≦&bgr;≦1000, (b) at least one compensation layer for compensating the optical path difference of the liquid-crystal layer d·&Dgr;n, and (c) at least one device for linear polarization of light in such an arrangement that light, before entering and after exiting the liquid-crystal layer, passes through a polarization device, I.

Abstract: In a liquid crystal display device comprising first and second substrates having first and second principal surfaces which are opposed to each other with a space left therebetween, first and second alignment layers are formed on the first and the second principal surfaces of the first and the second substrates. The first alignment layer is subjected to a first aligning treatment in a first aligning treatment direction while a second alignment layer is subjected to a second aligning treatment in a second aligning treatment direction which shifts from the first aligning treatment direction by a predetermined slight angle. Interposed between the first and the second alignment layers, a liquid crystal layer comprises a plurality of liquid crystal molecules each of which is twist aligned by a twist angle equal to the predetermined slight angle.

Abstract: A twisted nematic color liquid crystal display. The liquid crystal display comprises parallel glass substrates covered by a transparent electrode and an alignment film, a twisted nematic liquid crystal between the glass substrates, a retardation layer and polarizers. Between the glass substrates, a liquid crystal unit which forms the liquid crystal has a twist angle about 70 to about 180 about degree while free of an externally applying voltage. A product of anisotropy of refractive index for the twisted nematic liquid crystal &Dgr;n and the thickness d thereof, that is, &Dgr;n·d, is set in a range between about 1100 Å to about 2000 Å. Without using a passive device such as an external color light source or color filter, a multi-color or full color display is formed by an active controlling method of birefringence of electric field via applying a voltage on the transparent electrode.

Abstract: The characteristic of a visual-field angle is improved by improving a characteristic of the contrast of a liquid-crystal display element employed in a head mounted display apparatus which is used as an optical visualizing apparatus mounted on the head of an image viewer for viewing an image appearing in front of both eyes of an image viewer. The liquid-crystal display element for displaying an image comprises a liquid-crystal board as well as first and second polarizing boards sandwiching the liquid-crystal board wherein the polarization directions of the first and second polarizing boards are inclined in a slanting orientations so that the contrast characteristic in the horizontal direction can be kept unchanged while the characteristic of the contrast in the vertical direction can be changed. In this way, the angle of the visual field can be enhanced.

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: A liquid crystal display apparatus of the present invention, which has a plurality of display pixels arranged in a matrix, includes: a pair of substrates opposing each other; a liquid crystal layer placed between the pair of substrates; an alignment film formed on a surface of at least one of the pair of substrates opposing the liquid crystal layer and subjected to a treatment for aligning liquid crystal molecules in the liquid crystal layer; and a pair of polarizing plates placed so as to interpose the pair of substrates, wherein the liquid crystal layer is divided into at least two regions in each of the display pixels, alignment states of the liquid crystal molecules are different in the at least two regions, and one absorption axis of one of the pair of polarizing plates is substantially parallel to a 6-12 o'clock direction or a 3-9 o'clock direction.

Abstract: A twisted nematic liquid crystal-based electro-optic modulator with a twist angle between 0° and 90°, and preferably between 50° and 80° is provided. The modulator provides a relatively rapid switching time such as less than about 50 milliseconds, and provides relatively large extinction ratios, such as greater than −25 dB. Preferably the liquid crystal entrance director differs from the polarization direction by a beta angle of about 15°.

Abstract: The invention relates to a TN cell which contains a nematic liquid crystal having positive dielectric anisotropy and a twist angle of essentially 90.degree., between two substrates provided with electrode and alignment layers, where the product of the separation between the substrate plates d and the optical anisotropy d.multidot..DELTA.n [sic] of the liquid crystal is between 0.15 and 0.70 .mu.m, characterised in that the liquid crystal contains a doping component in order to improve the grey shade capacity, so that the cell has a value for the undisturbed quotient of the separation between the substrate plates d and the pitch of the liquid crystal p of 0.1.ltoreq.d/p.ltoreq.0.5.

Abstract: The present invention provides a liquid crystal display panel that can improve alignment stability, display uniformity, and display quality. By facilitating stable alignment of liquid crystal materials and inducing a twisted alignment, a uniform display can be provided and the balance among the optical characteristics can be improved. In particular, a stable alignment margin can be obtained when the cell thickness d is 7 .mu.m or more and when the twist angle for liquid crystal molecules is 240.degree. or less.

Abstract: A twisted nematic liquid crystal-based electro-optic modulator with a twist angle between 0.degree. and 90.degree., and preferably between 50.degree. and 80.degree. is provided. The modulator provides a relatively rapid switching time such as less than about 50 milliseconds, and provides relatively large extinction ratios, such as greater than -25 dB. Preferably the liquid crystal entrance director differs from the polarization direction by a beta angle of about 15.degree..

Abstract: A liquid crystal display device having a liquid crystal cell including: a pair of substrates at least one of which has light transparency; a chiral nematic liquid crystal layer having positive anisotropy of dielectric constant, disposed between the pair of substrates; and a voltage applying circuit for applying a voltage to the liquid crystal layer, wherein the liquid crystal layer contains a pleochroic dye, and liquid crystal molecules in the liquid crystal layer are twisted with respect to a helical axis perpendicular to surfaces of the pair of substrates, a twist angle of the liquid crystal molecules from one of the pair of substrates to the other of the pair of substrates is in a range selected from the group consisting of a range from 0.degree. to 50.degree., a range from 140.degree. to 250.degree., and a range of twist angles obtained by adding an integral multiple of n radian to the twist angles in the range from 0.degree. to 50.degree. and in the range from 140.degree. to 250.degree..

Abstract: A liquid crystal display is described in which the need for a conventional output polarizer is eliminated and the display comprises only a liquid crystal cell, a single input polarizer, a reflector placed behind the cell, and a retardation film placed between the reflector and the cell. A Jones matrix simulation approach is used in order to obtain the parameters corresponding to solution spaces for the above design and several combinations are disclosed that give good results.

Abstract: Supertwist liquid crystal displays (STN displays) of excellent characteristics are obtained if the nematic liquid crystal mixtures used therein comprise at least one compound of the formula IA ##STR1## and at least one compound of the formula IB ##STR2## in which R.sup.a, R.sup.b, Z, L.sup.a, L.sup.b, L.sup.c, L.sup.d, L.sup.e, L.sup.f, L.sup.g, L.sup.h, R.sup.3, R.sup.4 are as defined below.

Abstract: A color display that includes an array of pixels having a top side and an opposite bottom side. Each pixel includes a material having a first optical state exhibiting birefringence and a second optical state different from the first optical state. Each pixel also includes an element capable of driving the pixel to a selected one of the first optical state or the second optical state. A first selected group of pixels of the array has a first pair of axes of optical birefringence when each pixel of the first selected group is in the first optical state and at least a second selected group of pixels of the array has a second pair of axes of optical birefringence, different from the first pair of axes of optical birefringence, when each pixel of the second selected group is in the first optical state. A reflective layer is disposed adjacent the bottom side and a polarizing layer, having a predetermined polarity orientation, is disposed adjacent the top side.

Abstract: Supertwist liquid-crystal displays having excellent properties are obtained if the nematic liquid-crystal mixture comprises at least one compound of the formula I: ##STR1## and at least one compound of the formula I.sup.* : ##STR2## in which R.sup.1 is alkyl, alkoxy, alkenyl or alkenyloxy having 1 to 12 carbon atoms,R.sup.2 is alkyl or alkoxy having 1 to 8 carbon atoms,Z is --COO--, --CH.sub.2 CH.sub.2 or a single bond,one of the radicals L.sup.1 and L.sup.2 is F and the other is H,Alkenyl.sup.* is an alkenyl radical having up to 7 carbon atoms,L.sup.* is H or F, andR.sup.* is F or an alkyl group having 1 to 12 carbon atoms which is unsubstituted or non-substituted.

Abstract: A color display that includes an array of pixels having a top side and an opposite bottom side. Each pixel includes a material having a first optical state exhibiting birefringence and a second optical state different from the first optical state. Each pixel also includes an element capable of driving the pixel to a selected one of the first optical state or the second optical state. A first selected group of pixels of the array has a first pair of axes of optical birefringence when each pixel of the first selected group is in the first optical state and at least a second selected group of pixels of the array has a second pair of axes of optical birefringence, different from the first pair of axes of optical birefringence, when each pixel of the second selected group is in the first optical state. A reflective layer is disposed adjacent the bottom side and a polarizing layer, having a predetermined polarity orientation, is disposed adjacent the top side.

Abstract: A reflector includes a substrate, a plurality of convex/concave portions formed on the substrate, and a thin reflective film formed over the convex/concave portions. When light is incident upon the reflector from a certain direction, an intensity of reflected light in a viewing angle range of about -45.degree. to +45.degree. with respect to a regular reflection direction of the incident light is about 60% or more of an intensity of light which is incident upon a standard white plate from a direction inclined by about 30.degree. from a direction normal to the plate and is reflected to the direction normal to the plate.

Abstract: We invent a self-compensated twist nematic (SCTN) mode for reflective light valves with high optical efficiency nearly 100% and it has a saturation voltage below about 3 V and a relatively large tolerance in cell-gap non-uniformity compared to other prior arts. The invented SCTN mode is especially suitable for reflective light valves driven by active matrices fabricated on Si-wafers.

Abstract: The invention provides a reflective liquid crystal display which consists of just an input polarizer, the liquid crystal cell and a rear reflector which can be placed inside or outside of the liquid crystal cell. There is no rear polarizer and no retardation film compensation. The invention is capable of producing a high contrast, low chromatic dispersion display. Depending on the twist angle chosen for the liquid crystal cell, the display can be used in direct view or in a projection type display. The display can also be driven in an active matrix mode or in a passive matrix multiplexed drive mode. A full numerical simulation which takes into account the liquid crystal director deformation under the application of an electric field was used to optimize such displays.

Abstract: A liquid crystal cell filled with a polymer-dispersed liquid crystal layer 15 comprising liquid crystal droplets 15.sub.1 dispersed in a polymer 15.sub.2 between a first glass base plate 11 with a first transparent electrode 12 and a second glass base plate 13 with a second transparent electrode 14, is placed between crossed Nicols formed by a first polarizer 16 and a second polarizer 17, with a backlight 18 situated on the outer side thereof, the diameter of the liquid crystal droplets 15.sub.1 is between 3 .mu.m and 100 .mu.m, and the liquid crystal molecules in the liquid crystal droplets 15.sub.1 are twisted to between 30.degree. and 180.degree.. The liquid crystals used have a dielectric anisotropy .DELTA..epsilon. which is negative when the frequency of the electric field is high and positive when the frequency is low, and by adjusting the dielectric anisotropy .DELTA..epsilon. via the frequency of the electric field it is possible to form liquid crystal droplets of a desired diameter.

Abstract: A liquid crystal (LC) cell having LC phase gratings is disclosed. The LC cell includes alternating strips of a first single domain LC material having a twist angle with a magnitude and a positive sign, and a second single domain LC material having a twist angle with the same magnitude and a negative sign. The magnitude of the twist angle is approximately from 45 to 70 degrees. The first and second LC materials are twisted nematic LC materials or ferro-electric LC materials. The liquid crystal phase gratings operate preferably in a normally-black condition with low operating voltages of below 3 V and high optical diffraction efficiencies. The LC cell is used in reflective or transmissive spatial light modulators of displays.

Abstract: A twisted nematic liquid crystal (TNLC) cell used in reflective spatial light modulators (SLMs) of displays is disclosed. The TNLC cell includes front and rear substrates, and a TNLC material having a thickness d and a left-handed or right-handed twist angle .phi.. The TNLC material is sandwiched between the front and rear substrates, and the twist angle .phi. is approximately from 46.degree. to 62.degree.. A direction of directors of the TNLC material located nearest the front substrate forms an initial angle .beta. with a direction of linearly polarized light incident thereon. The initial angle .beta. is approximately from -6.degree. to 60.degree.. A birefringence .DELTA.n of the TNLC material times the thickness d is between approximately 0.7.lambda. to 1.25.lambda., where .lambda. is a wavelength of light incident on the front substrate.

Abstract: In a liquid crystal display device comprising a plurality of layer domains of a liquid crystal material between a first and a second substrate member with two adjacent ones of which domains made to serve as a first layer domain of a first twist angle of liquid crystal orientations and as a second layer domain of a second twist angle of liquid crystal orientations, an angle between the first and the second twist angles is selected between 80.degree. and 100.degree. with the liquid crystal material made to have a chiral pitch between 20 micrometers and 200 micrometers in each of the first and the second layer domains. Preferably, the liquid crystal orientations have a pretilt angle between 0.degree. and 1.50.degree. at an interface between the liquid crystal material layer domains and at least one of the first and the second substrate members.

Abstract: A TN-mode, normally-white format liquid crystal display device having high contrast and exceptional display characteristics. The angle of gradation inversion is increased and a straight-on contrast of more than 100 is obtained by setting the twist angle to 78.degree.-90.degree., preferably 84.degree.-90.degree., .DELTA..sub.n d to 0.3-0.4 .mu.m, preferably 0.35-0.38 .mu.m, and .DELTA..sub..epsilon. to at least 6.2.

Abstract: A nematic liquid crystal device with two bistable switched states, having two cell walls treated which provide a bigrating on one or both cell walls. The bigrating enables the liquid crystal molecules at a surface to lie in two different angular directions, 45 or 90 degrees apart. The bigrating may be symmetric or asymmetric, with the surface energy of each of the gratings of the bigratings being nearly equal.

Abstract: The present invention provides a liquid crystal display device including a pair of electrode substrates and a display medium sandwiched between the electrode substrates and including a polymeric wall and liquid crystal regions at least partly surrounded by the polymeric wall. In this liquid crystal display device, the polymeric wall is tightly attached to both the electrode substrates. Furthermore, the invention also provides a method for producing a liquid crystal display device including a pair of electrode substrates, at least one of which is transparent, and a display medium including a polymeric wall and liquid crystal regions at least partly surrounded by the polymeric wall and sandwiched between the electrode substrates.

Abstract: A liquid crystal display device comprising a first substrate having a first electrode and a homeotropic aligning film formed thereon, a second substrate having a second electrode and a homogeneous aligning film formed thereon, and a chiral nematic liquid crystal sealed between the first and second substrates. One % by weight of a dichroic dye is added to the chiral nematic liquid crystal. The liquid crystal molecules of this liquid crystal display device has a twist angle .theta. of 0.5.pi. radians or greater and smaller than (5/3).pi. radians. The cell gap d of the liquid crystal display device and the natural pitch p of the nematic liquid crystal are selected in such a way that d/p satisfies an inequality (9):(.theta./2.pi.)-(1/4)<d/p<(.theta./2.pi.

Abstract: The invention relates to a liquid-crystal display based on a twisted nematic cell and havingtwo substrates provided with electrode layers and alignment layers thereon and, with a frame, forming a cell,a nematic liquid-crystal mixture having positive dielectric anisotropy present in the cell, anda twist angle of the liquid-crystal layer in the cell with a value of between 0.degree. and 600.degree. from alignment layer to alignment layer,whose liquid-crystal mixture is based on medium-polarity compounds of the SFM type which are selected so that the liquid-crystal mixture has a viscosity at 20.degree. C. of less than 30 mm.sup.2 s.sup.-1 and has a value ofK/.DELTA..di-elect cons..ltoreq.1.5for the quotient of the Frank constant K ##EQU1## and the dielectric anisotropy .DELTA..di-elect cons..DELTA..di-elect cons.=.di-elect cons..vertline.-.di-elect cons..sub..perp.when used in a TN cell (.nu.=.pi./2, d/p<<1)K/.DELTA..di-elect cons..ltoreq.1.5where .nu.

Abstract: A liquid crystal electro-optical device comprising: a pair of insulating substrates; an electrode and an alignment film formed in this order on each of the insulating substrates; a liquid crystal layer interposed between the pair of insulating substrates, wherein the alignment film is a film capable of aligning the liquid crystal molecules in the liquid crystal layer perpendicularly with respect to the insulating substrates, and wherein the thickness of the liquid crystal layer is 45 to 70% of the twist pitch of the liquid crystal molecules.

Abstract: The invention relates to improved high-multiplexed supertwist liquid crystal displays in which each pixel is addressed by orthogonal row waver forms, the improvement wherein the nematic liquid crystal mixture consists essentially of 40-80% by weight of at least three compounds having a tolan-4,4'-diyl structure element.

Abstract: A liquid crystal shutter has a liquid crystal layer which is made of a liquid crystal material prepared from a nematic liquid crystal. The ratio d/p of the thickness d of the liquid crystal layer to the chiral pitch p of the liquid crystal material and a twist angle .theta. which is set by a pair of alignment layers for liquid crystal molecules of the liquid crystal layer satisfy the relation of .theta./360.degree.<d/p.

Abstract: The invention relates to a TN cell which contains a nematic liquid crystal having positive dielectric anisotropy and a twist angle of essentially 90.degree., between two substrates provided with electrode and alignment layers, where the product of the separation between the substrate plates d and the optical anisotropy d.multidot..DELTA.n ?sic! of the liquid crystal is between 0.15 and 0.70 .mu.m, characterized in that the liquid crystal contains a doping component in order to improve the grey shade capacity, so that the cell has a value for the undisturbed quotient of the separation between the substrate plates d and the pitch of the liquid crystal p of 0.1.ltoreq.d/p.ltoreq.0.5.

Abstract: A reflection-type liquid crystal (LC) device having a twisted nematic (TN) LC layer that lets linearly-polarized incident light enter and become circularly-polarized at a reflecting surface, and then linearly polarizes it, after reflecting, with a plane of polarization that has been rotated 90.degree. from the incident light at an light output surface. The TN LC layer allows linearly-polarized incident light to enter at an angle to the molecular plane of light input of the twisted nematic LC, and to linearly polarize the light after reflection. The plane of polarization is rotated 90.degree. from the incident light at the light output surface. The TN LC layer also allows circularly-polarized incident light to enter and become linearly-polarized light at the reflecting surface. Circularly-polarized light after reflection may be rotated opposite the incident circularly-polarized light at the light output surface to provide for reverse on/off states.

Abstract: A color display is formed by stacking two or more birefringent elements that are tuned to provide different spectral characteristics, and operating each of the elements independently.