Abstract: A false twist device for an open-end spinning device to introduce a false twist in a yarn has a largely tubular carcass and several false twist edges arranged behind one another in the yarn draw-off direction and inclined by an angle in the carcass with regard to the yarn draw-off direction. The false twist edges protrude in such a way into the interior of the tubular carcass that the yarn experiences a deflection on each one of the false twist edges. The several false twist edges are arranged offset in such a way in the carcass in circumferential direction that the yarn simultaneously experiences a spatial deflection compared to its regular yarn draw-off direction through the successive deflections on the several false twist edges.

Abstract: A false twist device (17) for an open-end spinning device (1) to introduce a false twist in a yarn (7) has a largely tubular carcass (20) and several false twist edges (19) arranged behind one another in yarn draw-off direction (G) and inclined by an angle (?) in the carcass (20) with regard to the yarn draw-off direction (G). The several false twist edges (19) protrude in such a way into the interior of the tubular carcass (20) that the yarn (7) experiences a deflection in each one of the false twist edges (19). Additionally, the several false twist edges (19) are arranged offset in such a way in the carcass (20) in circumferential direction that the yarn (7) simultaneously experiences a spatial deflection compared to its regular yarn draw-off direction (G) through the successive deflections on the several false twist edges (19).

Abstract: An electro-optical display device comprising a liquid crystal layer achieves switching using an electric field component which is predominantly parallel to the surface of the liquid crystal layer. Low dependence of image contrast on viewing angle is achieved by selection of parameters including pretilt angle ?0, orientation angle ?0, etc. of the liquid crystal molecules in the layer.

Abstract: A bobbin plate is described which is provided with yarn catching slits, with whose aid a yarn reserve winding is formed on a rotating empty bobbin tube. The bobbin plate comprises a base body as well as a nipping ring which can be pressed onto the base body and which nipping ring is flexible at its front side. The base body as well as the nipping ring are each provided with yarn catching slits in such a way that the caught thread can be nipped between the base body and the nipping ring. The supporting surface, on which the bobbin tube is disposed on the nipping ring, is so designed that a relative motion between the bobbin plate and bobbin tube is prevented.

Abstract: The invention relates to an electrooptical system according to the preamble of claim 1, where the angle &psgr;, which the polarization device forms on the input side with the directors of the liquid-crystal molecules on the 1st substrate surface, is optimized in order to achieve high contrast and/or high brightness and/or high viewing angle independence and/or the color values.

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: An electro-optical display device comprising a liquid crystal layer achieves switching using an electric field component which is predominantly parallel to the surface of the liquid crystal layer. Low dependence of image contrast on viewing angle is achieved by selection of parameters including orientation angle .beta..sub.o, and others, of the liquid crystal molecules in the layer.

Abstract: An electro-optical display device comprising a liquid crystal layer achieves switching using an electric field component which is predominantly parallel to the surface of the liquid crystal layer. Low dependence of image contrast on viewing angle is achieved by selection of parameters including pretilt angle .alpha..sub.0, orientation angle .beta..sub.0, etc. of the liquid crystal molecules in the layer. Reflection mode devices are described.

Abstract: The invention makes available an electrochromic right valve (1) with an active electrochromic layer (2) and a passive electrochromic layer (3). Between the two electrochromic layers is an electrolyte (4). Each of the electrochromic layers is connected to an associated electrode (5, 6). The active electrochromic layer can accept electrons from its electrodes and ions of a particular element from the electrolyte to become reversibly colored. The passive electrochromic layer acts as a reservoir for ions of the species concerned, donating such ions to and accepting them from the electrolyte. At the operating temperature of the electrochromic light valve, the passive layer is super-saturated with the element which provides the ions of the species concerned. The invention also covers a method of manufacturing the electrochromic light valve and uses of the valve.

Abstract: An electro-optical display device comprising a liquid crystal layer achieves switching using an electric field component which is predominantly parallel to the surface of the liquid crystal layer. Low dependence of image contrast on viewing angle is achieved by selection of parameters including orientation angle .beta..sub.o and pretilt angle .alpha..sub.o of the liquid crystal molecules in the layer. For example, good results are achieved when 0.degree.<.beta..sub.o .ltoreq.20.degree. for liquid crystal molecules having negative dielectric anisotropy and 70.degree..ltoreq..beta..sub.o <90.degree. for molecules having positive dielectric anisotropy. Preferably, 0.degree..ltoreq..alpha..sub.o <30.degree..

Abstract: The invention relates to an electrooptical display element which can be multiplexed, has two support plates which, with an edging, form a cell containing a pneumatic liquid crystal material with positive dielectric anisotropy, and at least one chiral additive, and has a small surface tilt angle and a twist angle with a value between 150.degree. and 250.degree., wherein the ratio of the elastic constants for bending and twisting K.sub.3 /K.sub.2 of the liquid crystal material and the twist angle are such that when using liquid crystal material with the ratio of the elastic constants K.sub.3 /K.sub.1 for mending and spreading, which is in the order of the maximum possible, the steepness of the characteristic line is approved by the characteristic line is bi-stable or when using liquid crystal material with the ratio of the elastic constants K.sub.3 /K.sub.

Abstract: A projector has a light source (1) for producing a parallel beam of white light (4); two dichroic prisms (21, 22) each having two dichroic colour-splitting layers, which on three of their sides have three liquid crystal light valve arrangements (23, 24, 25, 26, 27, 28) associated with different components of the color image; a lens (8) through which the color image components produced by the light valve arrangements (23 to 28) can be projected together on to a screen. The light valve arrangements (23 to 28) associated with the two dichroic prisms operate by reflection. Each of the two dichroic prisms (21, 22) is coupled with one of the outlets of a polarizing beam splitter (10), said outlets being associated with different polarizing directions. The polarizing beam splitter (10) distributes the beam of white light (4, 6) to the two dichroic prisms (21, 22) and directs the light of the activated image points travelling back from the two dichroic prisms into the lens (8).

Abstract: A suitable choice of the liquid crystal parameters K.sub.3 /K.sub.1 and .DELTA.E/E.sub.1 makes it possible in electrooptical display elements to obtain both a minimum dependence on the angle of observation and, simultaneously, a steep electro-optical characteristic when operated in the first transmission minimum.

Abstract: Liquid crystalline dielectrics having steep characteristic curves comprise 5-85% by weight of at least one carboxylic acid ester of formula (I)R.sub.1 --X--R.sub.2 (I)wherein X is --CO--O-- or --O--CO--, R.sub.1 is alkyl of 1-7 C atoms, R.sub.2 is ##STR1## and R is alkyl of 1-7 C atoms which can be the same or different from R.sub.1, and 95-15% by weight of at least one compound of the formulae (II) to (VI), ##STR2## wherein n is 1 or 2, Z is R', OR' or CN, R and R' being the same or different, and each being alkyl of 1-7 C atoms.

Abstract: A display device having a liquid crystal cell containing a medium, which can be switched zone-wise between at least two different optical states to form a light valve, a light trap in the form of a plate-shaped body disposed behind the liquid crystal cell when taken in a direction of observation of the device, the plate-shaped body having a material with an index of refraction greater than 1, containing fluorescent particles, and possessing a light emergent or outlet window at the rear of each switchable zone of the liquid crystal cell characterized by the light emergent or outlet windows comprising a groove in the plate and a light scattering surface disposed between the groove and the medium of the liquid crystal cell.