Abstract: The invention provides a liquid crystal (LC) composition, a LC device such as a liquid crystal display and a phase modulator, and a method thereof. The liquid crystal composition comprises a liquid crystal and a polymer. The liquid crystal exhibits a macroscopic anisotropic property such as optical property in the absence of the polymer under a condition such as certain temperature. The polymer in the composition stabilizes the liquid crystal so that the liquid crystal exhibits a macroscopic isotropic property under the same condition, and the liquid crystal stabilized by the polymer exhibits the macroscopic anisotropic property when an electrical field is applied thereon. The devices exhibit technical merits such as large viewing angle, fast response time, better contrast ratio, easy manufacturability of large size display with improved dark state, easy manufacturing process with wider temperature region, and polarization-insensitivity of PSI phase modulator, among others.

Abstract: A bi-stable active matrix (AM) display apparatus and a method for driving a display panel thereof are provided. The bi-stable AM display apparatus includes a bi-stable AM display panel, a scan driver, a data driver and a controller. A frame period is divided into a resetting phase and a determining phase. The controller resets pixels on a plurality of scan lines of the bi-stable AM display panel to a homotropic state in the resetting phase through the scan driver and the data driver. The controller writes frame information into the pixels on the scan lines in the determining phase through the scan driver and the data driver.

Abstract: A transreflective display in which the thickness of the liquid crystal layer is the same for both transmissive and reflective modes. The transmissive and reflective pixels are stabilized in two different liquid crystal configurations with different birefringences. The light retardation effect of one path in the transmissive pixels is close to or equals the retardation effect of two paths in the reflective pixels, resulting in synchronization of the two modes.

Abstract: The invention provides a liquid crystal (LC) composition, a LC device such as a liquid crystal display and a phase modulator, and a method thereof. The liquid crystal composition comprises a liquid crystal and a polymer. The liquid crystal exhibits a macroscopic anisotropic property such as optical property in the absence of the polymer under a condition such as certain temperature. The polymer in the composition stabilizes the liquid crystal so that the liquid crystal exhibits a macroscopic isotropic property under the same condition, and the liquid crystal stabilized by the polymer exhibits the macroscopic anisotropic property when an electrical field is applied thereon. The devices exhibit technical merits such as large viewing angle, fast response time, better contrast ratio, easy manufacturability of large size display with improved dark state, easy manufacturing process with wider temperature region, and polarization-insensitivity of PSI phase modulator, among others.

Abstract: A bistable switchable liquid crystal device is provided in which the device can be switched between a transparent and an opaque state by a predetermined voltage pulse. The device is based on polymer stabilized cholesteric materials. No additional amount of voltage has to be applied to the device in order to sustain the optical states. Therefore, the device is energy-saving.

Abstract: A transreflective display in which the thickness of the liquid crystal layer is the same for both transmissive and reflective modes. The transmissive and reflective pixels are stabilized in two different liquid crystal configurations with different birefringences. The light retardation effect of one path in the transmissive pixels is close to or equals the retardation effect of two paths in the reflective pixels, resulting in synchronization of the two modes.

Abstract: A device and method of manufacturing a single layer multi-state ultra-fast cholesteric liquid crystal includes two optically transparent states with a liquid crystal arranged therebetween, and changing the optical states of the liquid crystal ranging from one state to any combination of broadband reflection, tunable narrow band reflection, light scattering, and transparency in accordance with a voltage applied to the device. A surfactant can be added to reduce the response time and a dichroic dye may be added to include the property of light absorption and reduce the bandwidth. The device can provide any and all of the aforementioned optical states for infrared light, visible light, and ultra-violet light. The desired outputs can be formed according to need, so that predetermined optical states can operate with either no voltage or a particular voltage or voltage range.

Abstract: A dual frequency cholesteric display includes a pair of opposed substrates, wherein one of the substrates has a first plurality of electrodes facing a second plurality of electrodes on the other substrate. A dual frequency bistable cholesteric liquid crystal material is disposed between the substrates, wherein the material and the intersection of the first and second plurality of electrodes forms a plurality of pixels. By selectively applying high and low frequency voltages to the plurality of pixels, the high frequency voltage causes the material to exhibit one texture and the low frequency voltage causes the material to exhibit another texture. By adjusting a voltage amplitude value for each high and low frequency causes each pixel to exhibit a desired reflectance.

Abstract: A series of drive schemes are used to apply a single phase of at least one voltage pulse to drive a display with a bistable cholesteric liquid crystal material to a gray scale reflectance. Each drive scheme takes into consideration the initial texture of the cholesteric material and the range of voltages that may be applied between maximum and minimum reflectance of the material. Application of the single phase can be implemented by either time modulation or amplitude modulation.

Abstract: Bistable cholesteric liquid crystal material is disposed between opposed substrates, wherein one of the substrates has a first plurality of electrodes facing a second plurality of electrodes on the other substrate, wherein the intersection of the first and the second plurality of electrodes forms a plurality of pixels. The material is addressed by applying a preparation voltage across the first and second plurality of electrodes and then subsequently applying a selection voltage across the first and second plurality of electrodes. The material is then allowed to relax for a period of time, whereupon the preparation and selection voltages are reapplied. These steps are repeated until the liquid crystal material obtains the desired reflectance.

Abstract: A flat-panel liquid crystal display. The display includes a flat sheet of bistable chiral nematic liquid crystal material activated by a drive circuit that individually controls the display state of multiple picture elements. The driver circuitry activates the liquid crystal domains with various drive schemes which have any number of different phases to attain various addressing sequence times. At the end of each drive scheme, the texture of the liquid crystal material is allowed to provide either focal conic or twisted planar end states across the two-dimensional array of picture elements. Each drive scheme employs at least a preparation phase and a selection phase to predispose the liquid crystal material to one of the end states.

Abstract: A new liquid crystalline light modulating cell and material are characterized by liquid crystalline light modulating material of liquid crystal and polymer, the liquid crystal being a chiral nematic liquid crystal having positive dielectric anisotropy and including chiral material in an amount effective to form focal conic and twisted planar textures, the polymer being distributed in phase separated domains in the liquid crystal cell in an amount that permits the liquid crystal to change textures upon the application of a field and ruggedizes the structure. In still another embodiment, the material exhibits stability at zero field in a colored, light reflecting state, a light scattering state and multiple stable reflecting state therebetween, as well as being optically clear in the presence of a field. In yet another embodiment, the application of mechanical force to the cell changes the material from an optically clear state to a light reflecting state.

Abstract: Polymer/cholesteric liquid crystal dispersions are provided in which the liquid crystal phase separated from the polymer matrix to form droplets. The cholesteric liquid crystals were positive dielectric anisotropic. At a zero field condition, the liquid crystal in the droplets was bistable, that is, the liquid crystal can be in either the reflecting planar state or the scattering focal conic state. When the liquid crystal 101 was in the planar texture, the helical axis of the liquid crystal was more or less perpendicular to the cell surface; colored light 105 was Bragg reflected. When the liquid crystal 101 was in the focal conic texture, the helical axis was more or less parallel to the cell surface, incident light was scattering 106 in the forward direction.

Abstract: A liquid crystal shutter and a drive waveform for controlling the same is presented by this invention. The liquid crystal shutter includes two distinct layers of liquid crystal material where one layer has a right hand twist sense and the other layer has a left hand twist sense. An electric field is selectively applied to the layers of liquid crystal material which have dual frequency properties. Accordingly, when a low frequency is applied to the liquid crystal materials they exhibit a positive dielectric anisotropy and a homeotropic texture which is substantially transparent. When a high frequency electric field is applied to the liquid crystal materials they exhibit a negative dielectric anisotropy and a planar texture which is substantially reflective. The liquid crystal material may be selected to selectively reflect predetermined spectrums of light.

Abstract: A new liquid crystalline light modulating cell and material are characterized by liquid crystalline light modulating material of liquid crystal and polymer, the liquid crystal being a chiral nematic liquid crystal having positive dielectric anisotropy and including chiral material in an amount effective to form focal conic and twisted planar textures, the polymer being distributed in phase separated domains in the liquid crystal cell in an amount that stabilizes the focal conic and twisted planar textures in the absence of a field and permits the liquid crystal to change textures upon the application of a field. In one embodiment, the material is light scattering in a field-OFF condition and optically clear in a field-ON condition, while in another embodiment, the material is optically clear in a field-OFF condition and light scattering in a field-ON condition.

Abstract: A flat-panel liquid crystal display. The display includes a flat sheet of bistable chiral nematic liquid crystal material activated by a drive circuit that individually controls the display state of multiple picture elements at a refresh rate 1000 scan lines per second. The driver circuitry activates the liquid crystal domains into homeotropic states over a relatively long activation period and then, during a short (.about.1 msec.) selection period, either keeps the domains in a homeotropic state or initiate a transition to the transient twisted planar state. The drivers then activate the domains in an evolution phase to provide either focal conic or twisted planar end states across the two-dimensional array of picture elements.

Abstract: A new liquid crystalline light modulating cell and material are characterized by liquid crystalline light modulating material of liquid crystal and polymer, the liquid crystal being a chiral nematic liquid crystal having positive dielectric anisotropy and including chiral material in an amount effective to form focal conic and twisted planar textures, the polymer being distributed in phase separated domains in the liquid crystal cell in an amount that stabilizes the focal conic and twisted planar textures in the absence of a field and permits the liquid crystal to change textures upon the application of a field. In one embodiment, the material is light scattering in a field-OFF condition and optically clear in a field-ON condition, while in another embodiment, the material is optically clear in a field-OFF condition and light scattering in a field-ON condition.

Abstract: A new liquid crystalline light modulating cell and material are characterized by liquid crystalline light modulating material of liquid crystal and polymer, the liquid crystal being a chiral nematic liquid crystal having positive dielectric anisotropy and including chiral material in an amount effective to form focal conic and twisted planar textures, the polymer being distributed in phase separated domains in the liquid crystal cell in an amount that stabilizes the focal conic and twisted planar textures in the absence of a field and permits the liquid crystal to change textures upon the application of a field. In one embodiment, the material is light scattering in a field-OFF condition and optically clear in a field-ON condition, while in another embodiment, the material is optically clear in a field-OFF condition and light scattering in a field-ON condition.

Abstract: A light modulating reflective cell comprising a polymer-free chiral nematic liquid crystalline light modulating material is disclosed. The cell includes nematic liquid crystal having positive dielectric anisotropy and chiral material in an amount effective to form focal conic and twisted planar textures. The chiral material has a pitch length effective to reflect light in the visible spectrum, wherein the focal conic and twisted planar textures are stable in the absence of a field and the liquid crystal material is capable of changing textures upon the application of a field.

Abstract: A new liquid crystalline light modulating cell and material are characterized by liquid crystalline light modulating material of liquid crystal and polymer, the liquid crystal being a chiral nematic liquid crystal having positive dielectric anisotropy and including chiral material in an amount effective to form focal conic and twisted planar textures, the polymer being distributed in phase separated domains in the liquid crystal cell in an amount that stabilizes the focal conic and twisted planar textures in the absence of a field and permits the liquid crystal to change textures upon the application of a field. In one embodiment, the material is light scattering in a field-OFF condition and optically clear in a field-ON condition, while in another embodiment, the material is optically clear in a field-OFF condition and light scattering in a field-ON condition.