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In this paper we discuss a new dynamic drive scheme for bistable reflective cholesteric liquid crystal displays with high multiplexing level. Only two voltage levels (U and 0) are used for the addressing in this drive scheme. Addressing speed is about the time of the fast transition of a cholesteric liquid crystal from the homeotropic state to the transient planar state per line. The maximum value of using voltage is slightly overtop the critical voltage of a cholesteric-nematic transition. These facts make this drive scheme very perspective in application for such kind of displays.

Daylight is an inherent attribute of a sustainable building. Artificial reproduction of natural illumination under varying needs and environmental conditions has been made possible after the appearance of the new wave of solid-state light sources. Our work is devoted to the development of white light-emitting diode (LED) clusters consisting of red, green, blue, and white (RGBW) LEDs for implementation in a smart lighting system that is able to reproduce light with correlated color temperature (CCT) similar to daylight, high values of color rendering index, and luminous efficacy. A method for determination of the optimal contribution of each of the four LEDs is demonstrated and discussed. We show that only three LEDs-green, blue, and white (no red) can be used in many cases for reproducing daylight. Both luminous efficacy of radiation and actual luminous efficacy of the considered RGBW clusters as functions of the CCT are analyzed.

In this paper we have proposed the dynamic drive scheme for cholesteric liquid crystal displays (ChLCD) with high information content. Hysteresis properties of cholesteric liquid crystals (ChLC) combined with the fast transition of ChLC from the homeotropic state to the transient planar state are used for fast addressing. Schematic representation of voltage waveforms on rows, columns and resultant across pixels of a display is presented. In this dynamic drive scheme the time required for record of one display row in 4-5 times lower than the time of transition of ChLC material from the homeotropic state to the transient planar state.