Abstract: A polarization rotator is provided for rotating the polarization direction of linearly polarized light by any arbitrary angle other than 90°. The device comprises a layer of liquid crystal material disposed between alignment surfaces. In one mode, a 90° twist is induced in the liquid crystal director. An expression is provided for relating the retardation of the layer to the amount of polarization rotation and the angle between the polarization direction of incident light and the alignment direction at the input side of the liquid crystal layer.

Abstract: The present invention relates to organic chemistry, in particular, to synthesis of sulfoderivatives of the polycyclic compounds and fabrication of optically anisotropic coatings on their base. The indanthrone sulfoderivatives of the general structural formulas I or II capable of forming LLC phase are disclosed. The disclosed compounds could be used, in particular, for producing optically isotropic or anisotropic and at least partially crystalline films. The application also includes the liquid crystal systems based on the disclosed compounds, and anisotropic films. wherein n is 3 or 4, R?CH3, C2H5, OCH3, OC2H5, Cl, Br, OH, NH2, z is the value selected from the list including 0, 1, 2, 3, and 4, M—counterion, and j—number of counterions in a dye molecule, and which can be fractional in case of one counterion belonging to several molecules, and in case n>1, counterions may be different.

Abstract: The optical compensatory sheet has a transparent support and an optically anisotropic layer formed from liquid crystal molecules aligned in an average inclined angle of less than 5°. The optical compensatory sheet gives the retardation value in plane (Re) in the range of 10 to 1,000 nm and the retardation value along the thickness direction (Rth) in the range of 10 to 1,000 nm.

Abstract: A method and apparatus that includes a first waveguide segment that differentially changes the amplitude of the light relative to a first polarization orientation, a thickness of oriented liquid crystal or other birefringent material sufficient to delay one polarization component one-half wavelength relative to another, and a second waveguide segment that also differentially changes the amplitude of the light based on the polarization orientation. Also, an apparatus that includes a thin polarization converter that includes a thin first substrate that is substantially transparent to a wavelength of light, and a birefringent material deposited on one or more surfaces of the first substrate and oriented such that the polarization converter forms a half-wavelength birefringent plate for the light. Also, an apparatus having a first substrate surface, a second substrate surface, and a liquid crystal material between the first and second substrate surfaces to form a polarization converter.

Abstract: A novel polarization selective membrane is disclosed. The membrane comprises a liquid crystal molecule having a helical structure and selectively transmits specific polarized light and selectively reflects the other polarized light. The helical axis of the helical structure is practically oriented in the normal direction of the membrane plane, and the angle between the helical axis of the helical structure and the long axis of the liquid crystal molecules is from 5° to 85°.

Abstract: A polarized light extraction optical element is formed by a light-transmitting base material and a polarization separation layer laminated thereonto, this polarization separation layer being a liquid crystal layer made of a cholesteric liquid crystal. The thickness of the liquid crystal layer is smaller than the thickness that would be required to achieve a maximum reflectivity, so that part of one of the right and left circularly polarized light components is reflected with a reflectivity smaller than the maximum reflectivity.

Abstract: Disclosed herein is a process of producing a circularly-polarized-light-extracting optical element adapted to effectively prevent the appearance of bright and dark stripes on the screen of a display to avoid lowering of the displaying quality of the display. The circularly-polarized-light-extracting optical element includes a glass substrate 11, an alignment layer 12 laminated to the glass substrate 11, and a cholesteric layer 13 formed on the alignment layer 12, in which molecules are aligned in the sate of planar alignment due to the alignment-regulating action of the surface of the alignment layer 12. The cholesteric layer 13 has a first surface 13a on its glass substrate 11 side, and a second surface 13b opposite to the first surface 13a. Director directions of molecules on the first surface 13a of the cholesteric layer 13 are aligned in substantially one direction owing to the alignment-regulating action of the surface of the alignment layer 12.

Abstract: Disclosed are liquid crystal (LC) phase-retarders and linear polarizers and methods and apparatus for making the same. The liquid crystal phase-retarder is realized by a liquid crystal film structure having one or more phase retardation regions formed therein. Each phase retardation region has an optical axis specified by the direction and depth of orientation of liquid crystal molecules along the surface of the liquid crystal film structure. The liquid crystal linear polarizer is realized by a liquid crystal film structure having a chiral phase region within which liquid crystal molecules are cholesterically ordered. One or more nematic phase regions are formed along the surface of the liquid crystal film structure within which liquid crystal molecules are oriented along a direction and to a surface depth sufficient to realize one or more phase retardation regions therein having optical axes along the direction of liquid crystal molecule orientation.

Abstract: Provided is a circularly-polarized-light-extracting optical element adapted to effectively prevent lowering of displaying quality that is brought about by the appearance of bright and dark stripes on the screen of a display even when the circularly-polarized-light-extracting optical element is placed between circular or elliptical polarizers arranged in the cross nicol disposition. The circularly-polarized-light-extracting optical element 10 includes a liquid crystal layer 12 having cholesteric regularity with liquid crystalline molecules in planar orientation. The liquid crystalline molecules on a surface 12A, which is one of the two main opposite surfaces 12A and 12B of the liquid crystal layer 12, are wholly oriented in substantially one direction (director Da) and the liquid crystalline molecules on the other main surface 12B of the liquid crystal layer 12 are also wholly oriented in substantially one direction (director Db).

Abstract: The liquid crystal display apparatus according to the present invention includes a) the direction of the twist angle of molecule orientation of the twisted phase difference board (3) is reverse to the direction of the twisted orientation of the liquid crystal molecule of the liquid crystal devices (2), and the twist angle of the twisted phase difference board is smaller than the twist angle of the liquid crystal devices (2) by 10° to 40°; b) an angle between the liquid crystal molecule-oriented direction of the alignment film (23a) of the second substrate and the molecule-oriented direction of a lower polymer (32b) of the liquid crystal polymer layer lies in the range of 80° to 90°; c) an angle between an absorption axis of the first polarization board (1) and the liquid crystal molecule-oriented direction of the alignment film (23b) of the first substrate side lies in the range of 50° to 60°; d) an angle between the absorption axis of the second polarization board (4) and the molecule-oriented direction of a

Abstract: A circularly polarizing plate comprises a linearly polarizing membrane and a quarter wave plate. The quarter wave plate comprises an optically anisotropic layer A and an optically anisotropic layer B. The quarter wave plate has such an optical characteristic that a retardation value essentially is a quarter of a wavelength when the retardation value is measured at the wavelength of 450 nm, 550 nm and 650 nm. One of the optically anisotropic layers A and B is a layer made from liquid crystal molecules, and the other is a polymer film or a layer made from liquid crystal molecules.

Abstract: A cholesteric liquid crystal coating film 13′ is formed on an alignment layer 12 provided on a glass substrate 11 (FIG. 1(a)), and is subjected to a thermal alignment process at a temperature equal to or higher than the liquid crystalline phase transition temperature of a chiral nematic liquid crystal that constitutes the coating film (FIG. 1(b)). Active rays capable of activating optically active groups in the chiral nematic liquid crystal are applied to the cholesteric liquid crystal coating film 13′ to deactivate the optically active groups, thereby forming a cholesteric layer 13 having color-indicating regions with the desired areas and indication colors that have been created according to the active-rays-applied area and to the amount of active rays applied to the area (FIG. 1(c)). Thereafter, this cholesteric layer 13 is subjected to a thermal alignment process at a temperature lower than the liquid crystalline phase transition temperature of the chiral nematic liquid crystal (FIG. 1(d)).

Abstract: A polarizing element provided with a layer including liquid crystals and a polarizer having a transmission axis. The polarizing element of the present invention is structured such that liquid crystal molecules in the aforementioned liquid crystal layer have a chiral smectic texture of a helical configuration with respect to a axis, the axis is not along a direction normal to a surface of the liquid crystal layer (a z-direction), and a direction of an orthogonal projection of the axis onto the surface of the liquid crystal layer is substantially at 90° to the polarizer's transmission axis.

Abstract: Disclosed are super broadband circularly polarizing film materials and novels methods of fabricating and using the same. The circularly polarizing materials are made from a film of material, such as a CLC polymer having a cholesteric order, in which a liquid crystal material, such as a nematic liquid crystal material, is distributed in a non-linear fashion across the thickness of the film in a plurality of liquid crystal-rich and liquid crystal-depleted sites in the CLC polymer. The pitch of the helices of the CLC molecules in the polyermized CLC material varies in a non-linear (e.g. exponential) manner along the depth dimension (i.e. transverse to the surface) thereof. The resulting circularly polarizing materials have reflection and transmission characteristics over bands of operation approaching 2000 nm. Depending on the final spiral structure of the materials utilized, the CLC circularly polarizing materials reflect either left-handed or right-handed circularly polarized light.

Abstract: A polarizer construction is disclosed that includes a reflective polarizer disposed on a first side of the construction to transmit light having one polarization and reflect light having an orthogonal polarization, and one or more colored dichroic polarizers disposed on a second side of the construction. The one or more colored dichroic polarizers are arranged so that when the construction is illuminated from the first side, an observer viewing the construction from the second side will observe a first spectral distribution of visible light, and when the construction is illuminated from the second side, an observer viewing the construction from the second side will observe a second spectral distribution of visible light different from the first spectral distribution. Various display constructions using colored polarizers to achieve color changing and image reversal effects are also disclosed.

Abstract: A polarized electroluminescence element used for a display is disclosed. The polarized electroluminescence element includes a substrate, an orientation-inducing layer situated on the substrate and in a first direction of orientation, and a light-emitting layer situated on the orientation-inducing layer and made of a mixture of an electroluminescent material and an oriented material for emitting polarized electroluminescence, wherein the electroluminescent material and the oriented material are in a second direction of orientation corresponding to the first direction of orientation.

Abstract: An optical device has an E-mode polarizer. The optical device has an E-mode polarizer, a ¼ wave phase retardation plate, and a cholesteric reflective polarizer. The E-mode polarizer is a linear dichroic polarizer and enables extraordinary light to pass. The ¼ wave phase retardation plate is sandwiched between the E-mode polarizer and the cholesteric reflective polarizer.

Abstract: A polarized illumination system (10) in accordance with the present invention includes an illumination device (1) for emitting light beams and a polarizing device (2) aligned with the illumination device. The polarizing device has a first micro lens array (21), a second micro lens array (22), a birefringent crystal (23), and a plurality of half wave retardation plates (24) arranged in order. The birefringent crystal splits light beams into two, orthogonally polarized components, and the half wave retardation plates convert the polarization state of one of those components to match the state of the other component. The half wave retardation plates are attached to one side of the birefringent crystal. The structure of the polarized illumination system has low cost and high light utilization efficiency.

Abstract: A laminate polarizer has a dichroic polarizing sheet and a polarizing and scattering sheet showing anisotropy in scattering properties depending on a direction of polarization and being laminated on the dichroic polarizing sheet. An absorption axis of the dichroic polarizing sheet and an optical axis of the polarizing and scattering sheet in which polarized light is intensely scattered are in parallel to each other. A liquid crystal display is provided so that this laminate polarizer is disposed on a light source side of a liquid crystal panel as a polarizer.

Abstract: An active-radiation-curing liquid crystalline composition is applied to an alignment layer 2 formed on a base 1, and the liquid crystal alignment is regulated by the application of heat or the like, thereby forming a liquid crystal layer 3 having cholesteric regularity (FIG. 1(a)). Next, active radiation 4 with a predetermined radiant intensity is applied to the liquid crystal layer 3 through a photomask 10 (FIG. 1(b)), and this liquid crystal layer 3 is then brought into contact with a solvent 5 (FIG. 1(c)). As a result, the area 3b in the liquid crystal layer 3 not irradiated with the active radiation 4 is removed, while the area 3a in the liquid crystal layer 3 irradiated with the active radiation 4 remains; a semi-cured cholesteric layer 3′ having therein a predetermined pattern is thus formed (FIG. 1(d)).

Abstract: Switchable optical components such as switchable mirrors and variable retarders are fabricated using a unique class of materials. These materials are thin film composites comprising of porous inorganic films imbibed with liquid crystal materials.

Abstract: A flat plate collimator and backlight system capable of improving the display characteristics of liquid crystal display devices are obtained. In order to achieve this end, a collimator is provided which comprises a cholesteric liquid crystal layer exhibiting a selective-reflection wavelength band with respect to perpendicularly-incident light in the wavelength range &lgr;1 to &lgr;2 (&lgr;1<&lgr;2), and which satisfies the relation &lgr;0<&lgr;1 with respect to the maximum-emission wavelength &lgr;0 in the emission spectrum of the light source with which the collimator is used in combination, and a backlight system employing this collimator and light source is provided.

Abstract: A liquid crystal panel has a cholesteric filter and the quarter wave plate inserted between a glass substrate and color filter elements, and each section of the cholesteric filter reflects either right-handed or left-handed circularly polarized light component recognized as one of the three primary colors and the circularly polarized light components recognized as other primary colors toward a light source so as to recycle these circularly polarized light components, thereby enhancing the utilization factor of incident light without increase of power consumption.

Abstract: A reflector for reflecting a broad bandwidth of electromagnetic (EM) radiation, comprising a sheet comprising a large plurality of pairs of layers of transparent polymer material parallel to a surface of the sheet, each pair of layers having a difference in the index of refraction between the materials in each layer of the pair, the total thickness of each pair of layers in the large plurality of layers varying substantially continuously and non linearly across the thickness of the sheet, is disclosed.

Abstract: An optical compensatory sheet comprises an optically uniaxial or optically biaxial transparent stretched film. A Re retardation value in plane of the transparent stretched film measured at 550 nm fluctuates, in any direction parallel to the transparent stretched film surface, within the range of ±5 nm based on the average Re value in each direction. A Rth retardation value along a thickness direction of the transparent stretched film fluctuates, in any direction parallel to the transparent stretched film surface, within the range of ±10 nm based on the average Rth value in each direction.

Abstract: A novel polarization selective membrane is disclosed. The membrane comprises a liquid crystal molecule having a helical structure and selectively transmits specific polarized light and selectively reflects the other polarized light. The helical axis of the helical structure is practically oriented in the normal direction of the membrane plane, and the angle between the helical axis of the helical structure and the long axis of the liquid crystal molecules is from 5° to 85°. The membrane may be prepared by using a composition comprising a compound represented by Formula (I): wherein X represents a group having an optically active site, M represents a group having at least one aromatic carbocycle or aromatic heterocycle, Y1 and Y2 independently represent a bivalent group; R1 to R3 independently represent a hydrogen atom or an alkyl group, R represents an alkyl group.

Abstract: A circularly polarizing plate comprises a linearly polarizing membrane and a quarter wave plate. The quarter wave plate comprises an optically anisotropic layer A and an optically anisotropic layer B. The quarter wave plate has such an optical characteristic that a retardation value essentially is a quarter of a wavelength when the retardation value is measured at the wavelength of 450 nm, 550 nm and 650 nm. One of the optically anisotropic layers A and B is a layer made from liquid crystal molecules, and the other is a polymer film or a layer made from liquid crystal molecules.

Abstract: A transflective liquid crystal display providing a bright displayed image of high contrast in the transmission mode with less dependence on the viewing angle by combining a polarizer with an optically anisotropic element having a liquid crystal film in which a twisted nematic alignment stricture is secured to produce a circular polarizer and disposing the circular polarizer on the rear side of a transflector in the transflective liquid crystal display.

Abstract: A polarizing apparatus extracts light amount of which is increased by incidence of light (10, 12) having a plurality of planes of polarization, and by aligning the planes of polarization. This polarizing apparatus can be used as a polarizer for a liquid crystal display device (optical transducer), or can be disposed as a preliminary stage before a polarizer. Molecules of an optically active material (1) rotates the plane of polarization through an optical rotation angle &thgr;1 when a first vector component 10 of light having a horizontal plane of polarization passes, and rotates the plane of polarization through an optical rotation angle &thgr;2 (>&thgr;1) when a second vector component of light having a vertical plane of polarization passes. Therefore, light having a horizontal plane of polarization is amplified, and light having a vertical plane of polarization is reduced.

Abstract: A cholesteric film is formed into an optical device comprising a plurality of layers. 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 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 of the film in order to form the layers. This method may be used to produce a filter of reduced sensitivity to angle of incidence. In addition to the infrared reflecting layer, red and green reflecting layers are provided. For normally incident radiation, the red and green layers reflect red and green parts R and G, whereas the blue part B of the spectrum is transmitted.

Abstract: A circularly polarizing element is a laminate of n number of cholesteric liquid crystal layers that are laminated so that the helical axis in each liquid crystal layer extends in the direction of thickness, where liquid crystalline molecules in the cholesteric liquid crystal layers spiral in the same direction to form helixes. The cholesteric liquid crystal layers are wide-wave-range-covering liquid crystal layers adapted to selectively reflect circularly polarized light in wide wave ranges, and these selective reflection wave ranges overlap one another over a specified wide range. Each cholesteric liquid crystal layer is a single layer in which the helical pitch is varied in the direction of thickness so that the layer can selectively reflect circularly polarized light in a broadened wave range, and preferably covers a wave range of 200 nm or more.

Abstract: A circular polarizer having excellent circular polarization characteristics and a liquid crystal display device equipped with the circular polarizer. The circular polarizer is comprised of at least a polarizer and an optical anisotropic element having a phase difference of approximately ¼ wavelength in the visible light region and characterized in that the optical anisotropic element is comprised of at least a liquid crystal film with a fixed nematic hybrid orientation structure.

Abstract: An elliptically polarizing plate, comprising a polarizer, a first optical anisotropic layer having positive refractive index anisotropy and an optical axis of the anisotropy that is tilted, and a second optical anisotropic layer having negative refractive index anisotropy and an optical axis that is tilted, have accurate retardation compensation of a liquid crystal cell, and the liquid crystal display maintains a display contrast having a sufficient visibility when the viewing angle is changed and which does not generate colorization.

Abstract: A device for filtering at least a predetermined selected optical signal having a predetermined wavelength range from a series of optical signals, the device comprising: a polarisation alignment means for substantially aligning substantially orthogonal polarisation states of an optical input signal so as to produce a polarisation aligned optical signal; a polarisation manipulation means for imparting a controlled polarisation manipulation to the polarisation aligned optical signal so as to output a polarisation manipulated optical signal having one of at least two distinguishable polarisation states including a first polarisation state and a second polarisation state; and an optical separation means for spatially separating the selected optical signal from the series of optical signals when the polarisation state of the polarisation manipulated optical signal is in a first polarisation state, thereby forming a first and second output optical signal, and maintaining the spatial alignment of the selected optical

Abstract: A polarizing element for a liquid crystal display is disclosed having high brightness, and less coloration when viewed squarely or obliquely in a wide viewing angle range. The polarizing element is produced by providing a light-diffusion pressure-sensitive adhesive layer onto a reflective polarizing plate that separates incident natural light into reflected light and transmitted light both of which are composed of polarized light.

Abstract: A guest-host polarizer is disclosed that includes a host matrix, one or more first guest dyes disposed in the host matrix and oriented to absorb a first portion of visible light having a first polarization state, and one or more second guest dyes disposed in the host matrix and oriented to absorb a second portion of visible light having a second polarization state orthogonal to the first polarization state. Such guest-host polarizers can be used in various optical applications and display constructions.

Abstract: A polarizing plate comprises a light-scattering polarizing element and a light-absorbing polarizing element. The elements are so arranged that the polarizing transmission axis of the light-scattering polarizing element is essentially parallel to the polarizing transmission axis of the light-absorbing polarizing element. The light-scattering polarizing element has a polarizing layer comprising an optically isotropic continuous phase and an optically anisotropic discontinuous phase.

Abstract: A light-scattering film 10 is obtained by subjecting a birefringent material in a resin layer to orientation treatment, in which at least one component selected from a transparent resin 6 and a scattering material 7 is the birefringent material (e.g., a birefringent resin, a liquid crystalline material). According to the light-scattering film, in the case where a linear polarized light in which a vibrating direction and a propagating direction exist in a plane containing a surface-directional axis of the film and a thickness-directional axis of the film is incident at a film surface, the rectilinear transmittance of the incident light shows maximum at an oblique incident direction to the film surface (e.g., incident angle of 20 to 89°).

Abstract: A wide viewing angle polarizer having: a polarizing film; and a phase retarder adhesively laminated on at least one surface of the polarizing film through an adhesive layer, the phase retarder being made of a composite phase retarder constituted by a laminate in which a retardation layer B of a cholesteric liquid crystal-oriented solidified layer in a selective reflection wavelength range of not larger than 350 nm is supported by a retardation layer A of a thermoplastic resin exhibiting positive birefringence, the composite phase retarder being formed so that the laminate has Re of not smaller than 10 nm and Rth-Re of not smaller than 50 nm when Re and Rth are defined as Re=(nx−ny)×d and Rth=(nx−nz)×d respectively in which nx and ny are in-plane main refractive indices, nz is a thicknesswise refractive index, and d is a layer thickness.

Abstract: Provided is a circularly-polarized-light-extracting optical element adapted to effectively prevent lowering of displaying quality that is brought about by the appearance of bright and dark stripes on the screen of a display even when the circularly-polarized-light-extracting optical element is placed between circular or elliptical polarizers arranged in the cross nicol disposition. The circularly-polarized-light-extracting optical element 10 includes a liquid crystal layer 12 having cholesteric regularity with liquid crystalline molecules in planar orientation. The liquid crystalline molecules on a surface 12A, which is one of the two main opposite surfaces 12A and 12B of the liquid crystal layer 12, are wholly oriented in substantially one direction (director Da) and the liquid crystalline molecules on the other main surface 12B of the liquid crystal layer 12 are also wholly oriented in substantially one direction (director Db).

Abstract: A transflective liquid crystal display providing a bright displayed image of high contrast in the transmission mode with less dependence on the viewing angle by combining a polarizer with an optically anisotropic element having a liquid crystal film in which a twisted nematic alignment stricture is secured to produce a circular polarizer and disposing the circular polarizer on the rear side of a transflector in the transflective liquid crystal display.

Abstract: The present invention relates to heat-resistant and plarizers that use thin films of dichroic organic substances, mainly dichroic dyes applied on the surface of rigid or flexible substrates in which the molecules of the dichroic organic substance are arranged in the form of a crystalline grid. The purpose of this invention is to widen the spectral range of the polarizer operation while improving polarization characteristics. This dichroic polarizer includes a film having a portion at least consisting of a crystalline structure that comprises at least one dichroic organic substance, wherein the molecules or molecule fragments of this substance have a planar morphology. The dichroic substance consists of a dichroic substance having at least one crest on the spectral absorption curve within spectral ranges of 400 to 700 nm and/or 200 to 400 nm and 0.7 to 13 &mgr;m.

Abstract: In an illumination optical system comprising a light source unit, an integrator unit for homogenizing a luminous flux from the light source unit, and a light valve for modulating light from the integrator unit according to predetermined image information and outputting thus modulated light; effective luminous flux quantity adjusting means adapted to adjust a light quantity caused by an effective luminous flux on the light valve is disposed within or near the integrator unit.

Abstract: An object of the invention is to provide a small and low-cost variable polarization plane rotator that can control a rotation angle of the polarization plane easily, and an optical device using the same.

Abstract: A polarizing element and an optical element are provided that can form a semitransparent or other type of liquid crystal display which is excellent in contrast in a reflective display mode and also is excellent in luminance in a transmissive display mode utilizing a reflective polarizing plate. A polarizing element comprising a reflective polarizing plate and an absorptive polarizer, wherein the reflective polarizing plate separates an incident natural light into a reflected light and a transmitted light each comprising a polarized light, and the absorptive polarizer is arranged on one side of the reflective polarizing plate so as to transmit a polarized light comprising the transmitted light.

Abstract: A guest-host polarizer is disclosed that includes a host matrix, one or more first guest dyes disposed in the host matrix and oriented to absorb a first portion of visible light having a first polarization state, and one or more second guest dyes disposed in the host matrix and oriented to absorb a second portion of visible light having a second polarization state orthogonal to the first polarization state. Such guest-host polarizers can be used in various optical applications and display constructions.

Abstract: Disclosed are super broadband circularly polarizing film materials and novels methods of fabricating and using the same. The circularly polarizing materials are made from polymerizable CLC film material having a cholesteric order, in which a liquid crystal material, such as a nematic liquid crystal material, is distributed in a non-linear fashion across the thickness of the film in a plurality of liquid crystal-rich and liquid crystal-depleted sites in the CLC polymer. The pitch of the helices of the CLC molecules in the polyermized CLC material varies in a non-linear (e.g. exponential) manner along the depth dimension (i.e. transverse to the surface) thereof. The resulting circularly polarizing materials have reflection and transmission characteristics over bands of operation approaching 2000 nm. Depending on the final spiral structure of the polymeriable CLC materials utilized, the CLC circularly polarizing materials reflect either left-handed or right-handed circularly polarized light.

Abstract: A polarizing element 20 includes a cholesteric layer 21 that selectively reflects either one of right-handed and left-handed circularly polarized components of incident light, and an absorptive elliptical polarizing plate 22 that is laminated to the cholesteric layer 21. The polarizing plate 22 transmits elliptically polarized light that contains as its main component the circularly polarized component having the direction of optical rotation that is identical to that of the circularly polarized component selectively reflected by the cholesteric layer 21. In this polarizing element 20, the angle (angle of lamination) which the direction of the major axes of liquid crystalline molecules aligned on the absorptive-elliptical-polarizing-plate-side surface of the cholesteric layer 21, d1, forms with the direction of the major axis of elliptically polarized light produced by the absorptive elliptical polarizing plate 22, d2, falls in a specified angle range centering around 90°.

Abstract: A polarized light extraction optical element is formed by a light-transmitting base material and a polarization separation layer laminated thereonto, this polarization separation layer being a liquid crystal layer made of a cholesteric liquid crystal. The thickness of the liquid crystal layer is smaller than the thickness that would be required to achieve a maximum reflectivity, so that part of one of the right and left circularly polarized light components is reflected with a reflectivity smaller than the maximum reflectivity.

Abstract: A variable optical attenuator including: a birefringent element positioned to separate an input optical signal into two spatially separated, orthogonally polarized beams; a LC modulator positioned to receive the orthogonally polarized beams and selectively alter their polarizations; a reflective element positioned to reflect the beams back through the LC modulator and the birefringent element, wherein the birefringent element recombines orthogonally polarized components of the reflected beams to produce an output optical signal; and a controller coupled to the LC modulator to selectively cause the LC modulator to alter the polarizations of the orthogonally polarized beams, wherein during operation the controller is responsive to a request to variably attenuate the intensity of the output optical signal relative to the intensity of the input optical signal to one of multiple non-zero attenuation settings.