Local dimming light‐guiding plate type backlight system using alignment‐controlled polymer‐dispersed liquid crystals

A new technology which enables a local brightness control according to the displayed images has been expected in the thin and lightweight backlight systems to improve a contrast ratio and power consumption of the liquid crystal displays (LCDs). In this paper, we have proposed a novel local‐dimming backlight system using alignment‐controlled polymer‐dispersed liquid crystals as a light‐guiding plate and investigated the forming conditions of polymer‐dispersed liquid crystals to achieve both a high‐luminance ratio and a fast response speed. As a result, we found that a luminance ratio and response speed of the backlight system can be improved by using bifunctional LC monomer materials and forming fine and rigid polymer network in the LCs, and achieved high luminance ratio of 16:1 and fast response time less than 0.5 ms. In addition, we fabricated the twisted nematic‐mode LCD using the local dimming light‐guiding plate‐type backlight based on this design, and successfully realized eight times higher contrast ratio than that of the traditional twisted nematic‐mode LCD.     

Control of three-link underactuated manipulators using a switching method of fuzzy energy regions

In general, manipulators used for industry and in academic laboratories have actuators to drive each joint. On the other hand, underactuated manipulators handled by our research have some passive or free joints without actuators and brakes. We recently developed a switching method of fuzzy energy regions to control such manipulators. In such a method, it is necessary to design parameters related to energy regions and the gains of some partly stable controllers based on the computed torque method. Here, the switching method is applied for a three-link underactuated manipulator. We optimize such design parameters related to fuzzy energy regions by a genetic algorithm. The effectiveness of the present method is illustrated with some simulations. This work was presented in part at the 12th International Symposium on Artificial Life and Robotics, Oita, Japan, January 25–27, 2007     

Preparation of Laminin-apatite-polymer Composites Using Metastable Calcium Phosphate Solutions

1Introduction Themostimportantrequirementofapercutaneous deviceisthepreventionofbacterialinfectionthroughtheinterfacebetweenthematerialandtheskin.Therefore,a percutaneousdevicehastoadherefirmlytoskintissueandpreventepidermaldowngrowth.Previously,Aokietalp…     

Study on Pb-Bi natural circulation phenomena

For the development of 45w%Pb-55w%Bi cooled direct contact boiling water small fast reactor (PBWFR), experimental study on Pb-Bi-water direct contact boiling two-phase flow has been performed using Pb-Bi-water direct contact boiling two-phase flow loop. For stable start-up of the boiling flow operation, Pb-Bi single-phase natural circulation must be realized in a Pb-Bi flow system of the loop before water injection into Pb-Bi. The Pb-Bi flow system consists of a four-heater-pin bundle, a chimney, an upper plenum, a level meter tank, a cooler, and an electromagnetic flow meter. A stable Pb-Bi single-phase natural circulation was realized in the range of flow rate from 1.5 l/min to 4.8 l/min by heating Pb-Bi in the heater-pin bundle with a power up to 7.7 kW. The inlet and outlet temperatures of the heater bundle were in the ranges from 243°C to 278°C, and from 251°C to 278°C, respectively. The natural circulation flow was simulated analytically using one-dimensional flow model including frictional, form and drag forces. Total hydraulic head through the loop were calculated from Pb-Bi densities at measured Pb-Bi temperatures in the loop. It was found that the calculated flow rate agreed well with the measured ones, which indicated the validity of the analytical models.     

Novel screen technology for high‐contrast front‐projection display by controlling ambient‐light reflection

Abstract— One problem with front‐projection displays is that the screen contrast ratio decreases in bright ambient light. In this paper, we propose a new front‐projection display system that incorporates the control of reflection of ambient light in the screen design, providing a high contrast ratio even in a brightly lit room.     

Electron injection in "electron-only" devices based on a symmetric metal/silole/metal structure

We report on electron injection from two different metal electrodes into three silole derivatives, namely 2,5-di-(3-biphenyl)-1,1-dimethyl-3,4-diphenylsilacyclopentadiene (PPSPP), 1,2-bis(1-methyl-2,3,4,5,-tetraphenylsilacyclopentadienyl) ethane (2PSP) and 2,5-bis-(2', 2'-bipyridin-6-yl)-1, 1-dimethyl-3,4-diphenylsilacyclopentadiene (PyPySPyPy), previously employed as emissive and electron transport materials in molecular organic light-emitting diodes (MOLEDs). Silole films were sandwiched between symmetric Mg:Ag or bilayer CsF-Al electrodes. The steady-state current density-voltage characteristics were measured as a function of the silole layer thickness for the two cathodes. The trap-free space-charge-limited current based on time-of-flight measurements compared with the injected electron current for PyPySPyPy indicated that Mg:Ag contacts limit the injected current, while CsF-Al contacts behave as quasi-ohmic contacts. Similar findings were obtained for 2PSP and PPSPP allowing steady-state derived electron mobility parameters to be extracted. Based on space-charge-limited conduction analysis of the measured current-voltage characteristics, PyPySPyPy is found to be a superior electron transporting silole with approximately an order of magnitude higher electron mobility (2.0/spl times/10/sup -4/ cm/sup 2//Vs) compared with those of 2PSP (2.4/spl times/10/sup -5/ cm/sup 2//Vs) and PPSPP (5.2/spl times/10/sup -5/ cm/sup 2//Vs), which is significantly higher than that of the prototype electron transport material tris (8-hydroxyquinolinolato) aluminum (III) (Alq/sub 3/) (6.5/spl times/10/sup -7/ cm/sup 2//Vs) at 0.6 MV/cm.     

Progress in viewing‐angle properties of liquid‐crystal displays

Abstract— Viewing‐angle dependences of the contrast ratio and color shift of LCDs have been radically improved as evidenced by the increasing application of LCDs in high‐quality television. This paper describes the concept of optical compensation and the fundamental characteristics of the viewing‐angle property for various LC modes.