We have studied photo-induced effects in a p-type transistor based on a [1]benzothieno[3,2-b]benzothiophene (BTBT) derivative. Repetition of blue light irradiation and electrical characterization under dark reveals that its threshold voltage gradually shifts in the positive direction as the cumulative exposure time increases. This shift is slowly reversed when the transistor is stored under dark. The onset voltage defined as the gate bias at which the sub-threshold current exceeds a certain level behaves in a similar manner. Mobility remains more or less the same during this exposure period and the storage period. Time evolution of the threshold voltage shift is fit by a model assuming two charged meta-stable states decaying independently. A set of parameters consists of a decay constant for each state and the ratio of the two states. A single parameter set reproduces the positive shift during the exposure period and the negative shift during the storage period. Time evolution of the onset voltage is reproduced by the same parameter set. We have also studied photo-induced effects in two types of n-type transistors where either a pure solution of a perylene derivative or a solution mixed with an insulating polymer is used for printing each semiconductor layer. A similar behavior is observed for these transistors: blue light irradiation under a negative gate bias shifts the threshold and the onset voltages in the negative direction and these shifts are reversed under dark. The two-component model reproduces the behavior of these voltage shifts and the parameter set is slightly different among the two transistors made from different semiconductor solutions. The onset voltage shift is well correlated to the threshold voltage shift for the three types of organic transistors studied here. The onset voltage is more sensitive to illumination than the threshold voltage and its sensitivity differs among transistors.

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Battery life and outdoor visibility are two of the most important features for mobile applications today. It is desirable to achieve both low power consumption and excellent outdoor visibility on the display device at the same time. We have previously reported a new RGBW method to realize low power consumption and high luminance with high image quality. In this paper, the basic concept of a new RGBW calculation utilizing an “Extended HSV color space” model is described, and also its performance, such as low power consumption, color image reproducibility and outdoor visibility is presented. The new method focuses on the luminance-increase ratio by means of a White signal for the display image data, and derives the appropriate RGBW signal and backlight PWM signal for every frame period. This dynamically controlled system solves the problems of conventional RGBW systems, and realizes the same image quality as a corresponding RGB display. In order to quantify its color image reproducibility, a spectroscopic measurement has been completed using the Macbeth Color Chart. In addition, the advantages of high luminance by the new RGBW method is described. The converted tone curve with an RGBW method provides very high luminance, such as 1,000cd/m², and improved outdoor visibility. Finally, a newly developed 4.38-inch full-HD (1,080 × 1,920) 503ppi prototype LCD utilizing this new RGBW technology is described.

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We designed multilayer wavelength-selective reflector films by stacking thin-films of transparent polymer. The optimum structure of the multilayer is determined using a combination of characteristic matrix method and a version of genetic algorithm. Such multilayer films can be used in LCD devices to enhance the color saturation of the display.

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We estimated the dependence of the perceived depth on luminance ratio by increasing the distance between the front and rear planes of a depth-fused 3-D (DFD) display. When the distance is great, the perceived depth has the tendency of nonlinear dependence on luminance ratio, which is very different from the almost linear dependence in a short-distance conventional DFD display. In a long-distance DFD display, the perceived depth is split to near the front plane at 0-40% of the rear luminance, near the rear plane at 70-100%, and the midpoint of the front and rear planes at 40-60%. Thus, the luminance-ratio dependence of perceived depth changes widely with the distance.

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We describe an In-Cell Projected Capacitive Touch Panel in a display using IGZO TFT technology. The prototype demonstrates high signal-to-noise ratio (SNR) and pen input operation. The possibility of enlarging the display size beyond current limits makes this a highly promising approach for In-Cell Capacitive touch panels.

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Ultra-high luminance lamps emitting white light with a well-scattered blue spectrum from InGaN/GaN laser diodes and a phosphor-converted yellow spectrum show speckle contrast values as low as LED. Spectral behavior of the laser diodes is analyzed to find the reason why such low values are obtained. As a result, the PWM-driven, multi-longitudinal mode with dynamically broadened line-width is found to have a great effect on reducing speckle contrast. Despite using the lasers, such speckle-free lamps are considered to be very suitable for high-luminance and other various lighting applications.

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This paper, presents a high-speed full swing driver for a heavy-load flat-panel scan-line circuit. The high driving capability is achieved using the proposed Complementary Dual-Bootstrap (CDUB) technique. The scan-line CDUB driver was fabricated in a 0.35-µm CMOS technology. The measured results, under the flat-panel scan-line load model, indicate that the delay time is within 2.8µs and the average power is 0.74mW for a 5V supply voltage.

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In this paper, we propose a chromatic adaptation model based on the adapting degree according to the level of adapting luminance and chromaticity in various surround illuminants. In the proposed model, first maximum adapted cone responses are calculated through the estimation of adapting degree for viewing conditions then corresponding colors are reproduced from original colors using the ratio of maximum adapted cone responses between different viewing conditions. The purpose of this study is to produce chromatic adaptation transform applied to environment-adaptive color display system. As a result, our proposed model can give better estimation performance than prior models and be embodied easily as a linear model in display systems. So it is confirmed that the implemented system can predict corresponding-color data very well under a variety of viewing conditions.

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The iCAM06 has been used as an image appearance model for HDR image rendering. iCAM06 goes through the color space conversions of the several steps to present HDR images. The dynamic range of a HDR image needs to be mapped onto the range of output devices, which is called the tone mapping. However, tone compression process of iCAM06 causes white point shift and color distortion because of color-clipping and cross-stimulus. Therefore, we proposed a modified white-balanced method in low-chromatic region and a color adjustment method in IPT space to compensate the color distortion during in tone compression process. Through the experimental results, we confirmed the proposed compatible color adjustment method had better performance than iCAM06 and enhanced models.

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1 × N active multi-mode interferometer laser diode (MMI LD) is proposed and demonstrated to realize single-wavelength edge-emitter without using grating configuration. As the 1 × N active-MMI LDs are based on longitudinal mode interference, they have a potential of single-wavelength emission without incorporating any grating layer on/beneath active layer. The fabricated devices showed single-wavelength emission with a side mode suppression ratio (SMSR) of 12dB at a wavelength of 1.57µm.

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An on-chip SIDO DC-DC boost converter core that can be used for both battery and solar cell operating applications is proposed. The converter is able to supply a current of up to around 30mA with an on-chip driver and more than 100mA by using an off-chip power MOS driver. The cross regulation problem was solved by inserting an extra cycle. Efficiencies of 85% and 84% were achieved for each driving mode. Complicated maximum power point tracking (MPPT) controls are available for a solar cell operation. An embedded micro-computer can be used to calculate a complicated algorithm. The converter exploits 99% of the expected maximum power of the solar cell. The converter protects the leak current that flows through the solar cell when there is no light. The proposed protection circuits reduce the leak current by three orders of magnitude without any performance loss.

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An Ldi/dt effect model based on float ground in a plamsa display panel (PDP) driver system is established in this paper. The model is to analyze the noise which appears in power supply and float ground pins of driver integrated circuits. Considering printed circuit board wiring and switching parasitic parameters, firstly Ldi/dt effect due to integrated circuits transition, is explained on the entire float-ground circuit operation. Then an analytic model is deduced and validated, and good agreement is obtained with experimental results. Based on the model, sensitivity analyses of key parameters are done. Finally, design optimisations to prevent the Ldi/dt effect based on float ground are proposed and verified in a PDP system.

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Electromagnetic scattering and radiation in cylindrical electromagnetic bandgap (EBG) structure is analyzed. The radiated field from a line source placed inside the eccentric configuration of the cylindrical EBG structure and plane wave incident on the cylindrical EBG structure is numerically studied based on the method proposed by the authors in their early papers. Using the developed formulation, it is shown first time that when the cylindrical EBG is illuminated by plane wave of particular resonance frequencies, the field are strongly enhanced or shaded inside the cylindrical EBG structure and this effect depends on the angle of incidence of the plane waves. We give a deep physical insight into explanation of this phenomenon based on the Lorentz reciprocity relation for cylindrical structures.

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This paper describes how to design matching structures to improve the frequency characteristics of one-dimensional finite periodic structures. In particular, it deals with one-dimensional finite superlattices. A downhill simplex method is used to determine some of the structural parameters of the matching structure. Numerical examples show that this method is effective in improving the frequency characteristics of finite superlattices.

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Channel modeling, which is quite important for wireless communications system design, is difficult to be statistically generated from experimental results due to the expense and time constraints. However, with the computational electromagnetics method, the Electro-Magnetic (EM) field can be emulated and the corresponding EM wave propagation scenario can be analyzed. In this letter, the Finite Integration Technique (FIT) method is utilized to calculate the EM wave propagation of the onboard mobile communications in the cabin of an aircraft. With the simulation results, the channel model is established. Compared with Finite-Difference Time-Domain (FDTD), the proposed scheme is more accurate, which is promising to be used in the cabin channel modeling for onboard mobile system design.

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