Liquid crystal display devices (LCDs) are increasingly being used for displays in various portable instruments. Almost all LCDs presently used in them are twisted nematic type LCDs (TN-LCDs) among many suggested display modes. However, as application of TN-LCDs .expands, their narrow viewing angle gradually becomes a problem, and hence it becomes necessary to look over the other display modes again to use them properly, consdering their characteristics. Therefore, in this paper, the authors tried to systemize various liquid crystal display modes according to their molecular alignments and their optical eflects, and summarize their characteristics. As a recent trend of LCDs, the time-sharing multiplex or matrix driving technique for many segments has been generally used according to complexity of display information. This paper also describes about the driving technique and discusses the propriety of various display modes of liquid crystal to the technique.
Two capillary tubes are inserted vertically in the same vessel through the bottom. The ratio of flow rates through the two tubes is constant when the pressures and heights at the outlet ends of both tubes are the same. The smaller flow rate can be known by measuring the larger one with a suitable flowmeter, for example, a positive displacement flowmeter or movable flowmeter. These flowmeters can be used independently of the viscosity of the liquid. The following results are obtained from the experiment. 1) The same ratio is obtained whether the two tubes are located vertically or horizontally, and even if various kinds of liquids are used as samples. 2) The ratio can be changed by using tubes with different diameters. These results agree fairly with our theoretical considerations. The smallest flow rate experienced in this research is about 0.03 cm3/min.
A model for investigating the occurrence of current controlled negative resistance is proposed and analyzed while considering the drift lengths of electrons and holes injected into a semi-insulator with deep impurity levels partially occupied by electrons. Criteria for the occurrence and disappearance of the negative resistance are deduced by applying this model. These criteria are found to be strongly dependent on the concentration and capture cross section of the deep level. Experiments in relation to this model were carried out by using Au doped Si p-i-n diodes. The results show that the negative resistance occurs when ND/NAU (ND: donor concentration in the original Si substrate, NAu: concentration of Au atoms in Si) is in the range from 10-2 to 1 and disappears when ND/NAu becomes smaller than 10-2. These experimental results are in good qualitative agreement with the model proposed here.
Intercalation compounds of bromine with graphite fibers, prepared by benzene decom-position, were used as electrodes in a con-centration cell. The following merits of applying the graphite fibers were clarified ; 1) high open-circuit voltage, 2) easy circulation of bromine gas, 3) low internal resistance, 4) long life. The open-circuit voltage depended strongly on the weight of electrode material of compounds as well as on the geometry of bridges for bromine gas and for KBr solution. By keeping the anode and cathode of inter-calation compounds (300mg) at 70°C and 15°C, respectively, the open-circuit voltage of 65 mV and short-circuit current of approximately 0.7 mA were obtained. The cell showed a high degree of performance over long periods of time, in comparison with the cell having compounds of graphite powder.
Phosphors used for color picture tubes and fluorescent lamps are reviewed with a focus on their recent developments. These phosphors have held the largest markets in the industrial use of phosphors. Color picture tubes mainly use ZnS and Eu3+-activated phosphors. Tb3+-activated phosphors are suitable for use under a high beam-current density in projection color picture tubes. In order to render clearer pictures, it is required to develop more efficient red phosphors and green phosphors with a linear beam-current dependence of the luminescence intensity. Calcium halophosphate activated with Sb and Mn has been and will continue to be the most important fluorescent lamp phosphor. Rare earth activated phosphors also play an integral role in high-color-rendering three-conponent fluorescent lamps.
Various mass transport processes to cause morphological changes of the solid surface ware interpreted from the aspects of surface and volume diffusion. Explanations were made on the basic diffusion equation and the boundary conditions derived from the motive force of the transport. The kinetics were discussed on flattening of periodical surface gratings, grain boundary grooving, morphological instabilities of fibers and thin films, pore migration and diffusional creep.
The Ion Sensitive Field-Effect Transistor (ISFET) is a new device for sensing cation activity in the electrolyte. This device is similar to the conventional MOSFET except that the gate insulator is exposed to solution. The gate insulator plays the role of an ion selective electrode and its potential can be detected by its FET action. ISFET's have potential advan-tages over conventional ion selective electrode in their rapid response, small size and low output impedance, and are extremely attractive for biomedical applications. The chemical responses of ISFET's depend on its surface materials. A nearly ideal pH response, excellent stability and selectivity to other cations are obtained using Al203 or Ta2O5. On the other hand, SiO2 shows a poor response and it is proved that the oxygen content in Si3N4 surface degrades its properties as a pH sensor. Sodium-alumino-silicate glass (NAS glass), which is generally known as a material for pNa, pK selective glass electrodes, is utilized as a surface material for the pNa and pK ISFET. The selectivities of these devices are comparable to that of the conventional pNa pK glass electrodes. Some applications of ISFET are also described, that is, micro ion sensor, multi-ion sensor (pH and pNa), combined pH sensor, and pCO2 sensor.