摘要:
A polymer dispersion type liquid crystal display element is disclosed. The element has a polymer dispersion type liquid crystal sandwiched between a pair of substrates, each having an inside electrode. Liquid crystal droplets are dispersed either in a polymer matrix continuous phase or in a three-dimensional matrix-containing polymer. When no voltage is applied to the electrodes, the liquid crystal molecules in the droplets present a bipolar-form orientation pattern having at least two poles in the vicinity of the interfaces between the liquid crystal droplets and the polymer. When a clear point transition temperature of the liquid crystal is Tni, the pattern of bipolar-form orientation is maintained at least when the element is operating at a temperature in the range of 5° C. to (Tni−5)° C.
摘要:
A polymer dispersion type liquid crystal display element having a polymer dispersion type liquid crystal sandwiched between a pair of substrates, each having an inside electrode, is disclosed. The liquid crystal has liquid crystal droplets dispersed and held in either a polymer compound-containing continuous phase matrix or a three dimensional network of such a matrix. In one embodiment, the capacitance hysteresis, defined as Chys=(C2−C1)/Cmax, does not exceed 1.5%. C1 is the capacitance for an applied voltage that is in the process of rising a voltage-capacitance characteristic; C2 is the capacitance of an applied voltage in the process of dropping; and C2 is the capacitance of a maximum applied voltage. In another embodiment, the Chys value does not exceed 0.6% when the optical hysteresis Thys is (P2−P1)/Pmax where P1 is the intensity of transmitted light of an applied rising voltage V, P2 is the intensity of transmitted light of an applied dropping voltage, and Pmax is the intensity of transmitted light of a maximum applied voltage.
摘要:
A method of making a polymer dispersion type liquid crystal display element including a phase separation step. The method calls for placing a liquid crystal polymer precursor compatible solution having a liquid crystal and a polymer precursor between a pair of substrates, each having an inside electrode, and irradiating a substrate surface with ultraviolet. The radiation causes a phase separation of the liquid crystal and the polymer precursor as well as polymerization and curing of the precursor. The method forms a polymer dispersion type liquid crystal having liquid crystal droplets dispersed and held in a continuous matrix phase or a three-dimensional network matrix. During the phase separation step, the irradiation time is controlled from the beginning of irradiation to the completion of phase separation to influence any of the degree of polymerization of the precursor in the solution, the rate of phase separation, and the generating density of the separated liquid crystal nuclei so that the dispersed liquid crystal droplets have even particle sizes.
摘要:
In a liquid crystal display element in which liquid crystal droplets are dispersed and held in polymer composition sandwiched between a pair of substrates each having an electrode at the inside thereof, the liquid crystal droplets are formed to have substantially the same shape and size with minimized variations in particle size so that the liquid crystal droplets can be stably kept in the bipolar-form orientation pattern within a wide temperature range, to minimize hysteresis of transmittance of light to a voltage applied across the electrodes. Similar effects can be produced by tilt angles of liquid crystal molecules in the vicinity of interface between the liquid crystal droplets and the polymer compound being minimized or by anchoring strength being increased, by adding an interfacial restrictive force controlling material to a liquid crystal polymer precursor compatible solution or raising a temperature under which polymerization of polymers and phase separation between the polymer and the liquid crystal are performed by irradiation of ultraviolet. Also, an improved response to electric field can be provided within a wide operation temperature range by allowing surface tension of liquid crystal material to be smaller than critical surface tension of an insulating film or surface tension of the polymer compound. Accordingly, the liquid crystal display element is available for forming displays, such as television sets and personal computers, capable of displaying moving pictures and the like within a wide operation temperature range.
摘要:
A polymer dispersion type liquid crystal display element having liquid crystal droplets dispersed and held in a continuous matrix phase including polymer compound or a three dimensional network form of matrix including polymer compound dispersed between a pair of substrates, each having an inside electrode. The liquid crystal droplets are in all areas but for an area in the vicinity of the interfaces between the substrates. The liquid crystal droplets are ellipsoid of revolution forms of substantially the same size.
摘要:
A method of forming a polymer dispersion type liquid crystal display element having a polymer dispersion type liquid crystal sandwiched between a pair of substrates, each having an inside electrode, is disclosed. The droplets either are dispersed and held in a continuous matrix phase of the polymer or held in a three dimensional network of a matrix containing the polymer. In the method, the value of (V90×R/d is at least 0.7 where V90 is that voltage required for transmittance of a voltage-transmittance characteristic of the display element to be 90% when the element is at 30° C., d is the interval between the substrate pair, and R is the average particle size of the liquid crystal droplets. In the method, a liquid crystal polymer precursor compatible solution containing a liquid crystal and a polymer precursor placed between the substrate pair is held at a temperature greater than the thermal phase separation temperature of the precursor solution, which is irradiated with ultraviolet to permit phase separation of the liquid crystal and the polymer precursor.