With progress of mobile computing devices, low power consumption backlighting for LCD has been demanded. Generally, CCFL (Cold Cathode Fluorescent Lamp) has been used as a high efficiency backlighting. We report our new developed CCFL based on the pulsed discharge in Xe-Hg which has much better efficiency at low power consumption and at low ambient temperature than conventional CCFL.

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This paper is stated about the new type of flat fluorescent lamps for LCD backlighting, which utilizes xenon dielectric barrier discharges. The lamps are made of two glass plates. The structure is very simple. The lamps are featured, as described below. (1) Stable luminous characteristics in every lamp size. (2) Good operation in low temperature. (3) Excellent luminance uniformity. (4) High luminance and high luminous efficacy. (Sine wave operation : 5000cd/m^2,18lm/W Pulse wave operation : 3500cd/m^2,27lm/W) (5) Stable luminance maintenance during operation.

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This report intoroduces the developed Reflector Type LED Lamp with high brightness and wide visibility angle that is a light source used on LED display boad at a high place outdoors. This Reflector Type LED Lamp has suitable characteristics for this situation. Because of the optical and structural characteristics of the Reflection type LED. The lenz type LED generaly used is superseded.

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In the present paper, we fabricated the FEAs made of n-type silicon, and n-type silicon covered with metal. We measured I-V characteristics and the energy distribution of the field emitted electrons by the retarding field method. The electron emitted from the FEAs covered with metal in lower applied voltage than non-covered one. The energy distribution of electrons emitted from Si-FEAs is broader than that from the FEAs covered with metal.

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It has been tried to make the phosphors used in usual CRT such as Zn_<1-x>Cd_xS : Ag, Cl and Y_2O_2S : EU conductive by some methods such as the addition of conductive In_2O_3 powder to the phosphors, the formation of Cu_xS layer, carbon deposition and the formation of In_2O_3 layer by sol-gel method on the phosphor surface. It was shown that the addition of In_2O_3 and the formation of In_2O_3 layer is quite effective for not only the cathodoluminescence of Zn_<1-x>Cd_xS : Ag, Cl phosphor but also that of Y_2O_2S : Eu phosphor excited lower voltage than 500V.

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A color PDP which represents color pictures uses phosphors excited by vacuum ultraviolet light (VUV) generated in gas discharge. Therefore, it is necessary to measure phosphor and its screen characteristics under VUV excitation. In this report, we describe an apparatus to measure optical properties of phosphor screen applying a VUV excimer lamp as an excitation light source, and discuss the results of dependence on phosphor screen thickness of brightness and effects of a reflection layer.

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Y_2O_3,which is a dielectric, mixed with Al thick-film paste was screen printed as a cathode. And Y_2O_3 also works as a cathode when it is thick-film printed on an Al bus-line. This cathode enables discharge voltage to be 80V lower than that of Al cathode, and has more than 10,000-hour lifetime. Brightness and luminous efficiency, however, were not improved. It can be adapted as a cothode of DC-PDP with optimization of gas pressure and its composition, and improvement of cathode structure such as combination with transparent electrode.

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For the purpose of investigating the characteristics of secondary electron emission by ion from the protecting layer materials of plasma displays, we constracted an experimental apparatus. The secondary electron emission characteristics are discussed concerning the properties for stainless, sheet MgO film, and optically trasparent materials for ultravioret rays.

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The enlargement of phosphor area for a discharge cell at its maximum is one of the most efficient methods to realize high luminance and high luminous efficiency in modern color PDPs. However the enlargement of phosphor area causes life time shorter because probability to sputter phosphors by ions becomes very high. In order to remove the disadvantage, we proposed double protecting layer which consist of the MgF_2 layer and MgO layer.

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Wall charges play an important role on the stability of light emission from the sustain discharges in AC-PDPs. AC/DC hybrid PDPs employed in the experiments separate functions of write and sustain discharges. Initial amount of wall charges were measured, and luminous intensity variation of sustain discharges was observed. It was found that the stability of the luminous intensity depends largely on an amount of the initial wall charges, and that its characteristics can be explained qualitatively using the voltage transfer curve. A new sustain driving waveform is proposed to improve the emission stability.

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The density of VUV-emitting Xe (1s_4) atoms in a micro-cell of color PDP was measured by laser spectroscopic microscopy. Under our experimental condition, (He-Xe (10%), total 2.67 X 10^4 Pa and total 4.66 X 10^4 Pa), a positive column was observed when the gap between the electrodes was larger than 350 μm. We found that a higher gas pressure was desirable to utilize the positiive columns effectively.

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Color PDPs utilize the pulse-number-modulation-within-a-field technique for expressing gray levels. When moving images are displayed on the PDPs, disturbances of color and gray levels are often observed. These disturbances are originated from a temporal non-uniformity which is transfered to a spatial non-uniformity by the motion of an observation point on the panel. The paper introduces simulation and experimental results of the disturbances. Appearance of the dynamic false contours depends on a speed of an observation spot, a duration of light emission blocks, a light emission distribution within a TV field, and an arrangement of discharge cells within a pixel, but not largely on a light-emission duty factor. A motion of a color pattern with gray scale results in appearance of the false colors. When a magenta gradation pattern for instance moves, a pair of moving red and blue false colors appears.

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In order to clarify the detailed mechanism of rubbing process on the polymer surface, we have observed the rubbed polymer surface by only one fiber in order to symplify the ordinary rubbing process in which overlapping of the rubbing complicates the surface structure. In this experiment, we observed the grooves formed by the rubbing by using AFM and FFM and compered them with the shape of the fiber observed by SEM. As the result, we found that the structure of the microgroove is strongly related to the edge shape of the fiber. Therefore, it is suggested that the microgrooves are formed by the microstructure of the edge of the fiber. We also measured the surface anchoring strength, and found that the rayon fiber gave larger value. The reason is considered that rayon fiber has smooth edge and therefore shallow but wide grooves were formed, by which the rubbed area was increased and induced the stronger anchoring.

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The mechanism of the liquid crystal molecule(5CB) alignment by the polarized UV irradiated polymer film has been examined by the spectroscopic method like UV/vis and IR. Consequencely it became clear that crosslinking of PVCn fairly depends on the temperature of the substrate, especially 5CB alignment is improved by the use of irradiating with UV light to PVCn through heating the substrate above Tg.

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In a recent paper [Phys. Rev. E, 52,681 (1995)] we showed that in the absence of an external field the twisted structure of substrates with weak anchoring can induce a deviation of the directors at the surfaces from an easy axis and that the anchoring energy can be evaluated by measuring this deviation. To test the prediction, the anchoring energy for nematic 4-pentyl-4'cyanobiphenyl and the polyimide Langmuir-Blodgett (LB) substrates with thicknesses in the range of <10nm has been measured.

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The alignment of liquid crystals on surface of polymers, which are made of a liquid crystalline monoacrylate, a non-liquid crystalline diacrylate and a non-liquid crystalline monoacrylate has been studied. We found that the alignment of liquid crystal on surface of polymer made of a liquid crystalline monoacrylate is homeotropic, that of a non-liquid crystalline diacrylate is parallel to the surface of polymer and that of non-liquid crystalline monoacrylate is homeotropic. The relation of alignment and chemical structure of acrylates is discussed.

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We have tried to apply the Polyurethane-Elastomer (PUE), which physical properties change reversibly by thermal treatment, to the alignment film for Amorphous Twisted Nematic Liquid Crystal Display (a-TN-LCD). The LC alignment on the PUE film surface is investigated by the measurement of the order-parameter and the contact angle of LCs (5CB) at various temperature. It is confirmed that the interaction between LCs and the PUE film come to weak at the temperature above Tg of the PEU. By using the PUE for alignment film, it is easily possible to obtain the amorphous alignment by the annealing above Tni after injecting LCs into the non-rubbed cell at the room temperature.

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Elastic constants of liquid crystals are very important parameters for physical studies of liquid crystals and for liquid crystal display. In this paper, a new method is proposed to determine elastic constants K_<11>/K_<33> and K_<11> of nematic liquid crystals by measuring relationships of optical retardations and capacitances versus electric fields at high electric fields. At first, we introduce theoretical formulas for the elastic constants, and then show this experimental method and experimental results of elastic constants for some kinds of liquid crystals.

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A multi-field-driving method which reduces not only the dynamic power consumption but also the static power consumption of LCD driving circuit has been developed. In this method, one frame is divided into several interlaced sub-field images, and a lower driving frequency operation of TFT-LCD is achieved. The applicability of this method was confirmed by using a 9.5" VGA TFT-LCD. Total driving circuit power consumption was reduced to less than half compared with that of conventional methods for all displayed images. In addition, displayed images were sufficient for practical use without visible image degradation, such as flicker and crosstalk.

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We investigated the relation between the easiness to read and the luminous reflectance of reflective LCDs and their contrast by subjective evaluation. Five scale subjective evaluation was carried out for forty people using fifty monochrome images including characters and a photograph, each printed on a glossy paper with its luminous reflectance and contrast varied. The perpendicular illuminance of the desk was 500lx. From this evaluation, the permissible limit curve of the luminous reflectance and contrast was calculated from the experimental equation introduced to relate the average value of the evaluation with the luminous reflectance and the contrast using the method of least squares.

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A new type of reflective color LCD has been developed with MIM (Metal-Insulator-Metal) elements and the higher transmissive color filters. To achieve this LCD panel, we have examined various kinds of parameters. We will discuss the thickness of the lower glass substrate for LCD, the property of color filter, the color pixel arrangement, the property of reflector, and the liquid crystal display modes, etc.

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Reflective liquid crystal displays (LCDs) attract many interests for its light weight and low power consumption. We propose a new type of reflective LCD mainly comprising a Hybrid-aligned nematic LC-layer, a biaxial-retardation film, a light scattering film and a mirror electrode. This new type of reflective LCD has advantage of high resolutions owing to the mirror electrode and wide viewing angle by designing with the same concept of the OCB mode. In this paper we describe the optimum condition of light scattering film for this new reflective LCD.

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The possibility of using holographic polymer dispersed liquid crystal (HPDLC) for a full-color reflective display was confirmed. An HPDLC device is an electrically controllable hologram formed by tiny liquid crystal droplets in a polymer. It is fast enough for a moving picture display, can produce grayscale, and has high color purity. Since the device is polarization independent and stackable, it can use ambient light very efficiently. A method to control the color of a device is established, and a 32×32 pixel monochrome display driven by thin-film transistors (TFT) is made, proving that HPDLC has potential use for full-color displays.

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The SmC^* liquid crystal was filled in isotropic phase in the cell with a pair of parallel electrodes on the same substrate and cooled down, and a horizontal electric field (HEF) was applied between two electrodes. The E-O property of the HEF cell shows hysterisis, and the contrast ratio reaches about 30. The optical switching response of the HEF cell gives out an explicit proof of the hindered rotational motion of the long axis of SmC^* liquid crystal molecules, the switching time is less than 5ms, and the switching current is about 10^<-9> A. In our experiment it was observed that the FLC molecules near the surface could not be rotated until the applied voltage was above 2.0V/μm.

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