We have succeeded in developing high-performance p-type of organic semiconductors with phenylethynyl groups, which have high filed-effect mobilities (> 3cm²V^-1s^-1) by improving molecular planarity. A single crystal of the organic semiconductors has a herringbone structure. It plays an important role for carrier transport. In addition, we found that they had lower contact resistances to Au electrodes as well. Then, we used the materials for the carrier injection layer deposited onto another organic semiconductor we developed recently, which achieved a high field-effect mobility, and a low threshold voltage (V_th).

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Thin-film transistors based on Liquid-crystalline phenylterthiophenes, 3-TTPPh-5 and 3-TTPPhF4-6 are fabricated with a spin-coating method. The devices exhibit p-type operation with the mobility on the order of 10^-2cm²V^-1s^-1. The field-effect mobilities of the transistors using 3-TTPPh-5 and 3-TTPPhF4-6 are almost independent of the temperature above room temperature. In particular, the temperature range in which the mobility is constant is between 230 and 350K for 3-TTPPh-5.

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Solution-based organic field-effect transistors (OFETs) with low parasitic capacitance have been fabricated using a self-aligned method. The self-aligned processes using a cross-linking polymer gate insulator allow fabricating electrically stable polymer OFETs with small overlap area between the source-drain electrodes and the gate electrode, whose frequency characteristics have been investigated by impedance spectroscopy (IS). The IS of polymer OFETs with self-aligned electrodes reveals frequency-dependent channel formation process and the frequency response in FET structure.

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This report describes a crystallization method we developed for amorphous (a)-Si film by using 405-nm laser diodes (LDs). The proposed method has been used to fabricate bottom gate (BG) microcrystalline (µc)-Si TFTs for the first time. A µc-Si film with high crystallinity was produced and high-performance BG µc-Si TFTs with a field effect mobility of 3.6cm²/Vs and a current on/off ratio exceeding 10⁸ were successfully demonstrated. To determine the advantages of a 405-nm wavelength, a heat flow simulation was performed with full consideration of light interference effects. Among commercially available solid-state lasers and LDs with wavelengths having relatively high optical absorption coefficients for a-Si, three (405, 445, and 532nm) were used in the simulation for comparison. Results demonstrated that wavelength is a crucial factor for the uniformity, efficiency, and process margin in a-Si crystallization for BG µc-Si TFTs. The 405-nm wavelength had the best simulation results. In addition, the maximum temperature profile on the gate electrode through the simulation well explained the actual crystallinity distributions of the µc-Si films.

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We have studied effects of additive elements into the channel layers of amorphous IGZO TFTs on threshold voltage shift issues under light illumination stress condition. By addition of Hf or Si element, the V_th shift under light illumination and negative bias-temperature stress and illumination stress conditions was drastically suppressed while the switching operation of TFTs using IGZO with Mn or Cu was not observed. It was found that the addition of Si or Hf element into the IGZO channel layer leads to reducing the hole trap sites formed at or near the gate insulator/IGZO channel interface.

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Well-crystallized Ba₂SiO₄: Eu²⁺ powders were grown on a substrate by the vapor phase reaction between a mixed powder (barium carbonate and europium oxide) and SiO gas. The vaporization of SiO occurs at 1400-1600°C from the SiO₂ source (or SiO powder) in a reducing atmosphere. The formed SiO gas was transported by 95 vol% Ar - 5 vol% H₂ gas and reacted with the raw material powders. The emission intensity of the Ba₂SiO₄: Eu²⁺ phosphor synthesized by the new vapor phase technique is about 2.6 times higher than that of a conventional solid-state reaction sample.

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We proposed a novel UV curable reactive mesogen monomer for VA-LCD with Polymer-Sustained (Stabilized) Vertical Alignment (PSVA) which shows a high display performance. The experimental results reveal that the PSVA by the novel-monomer realizes less image sticking and better response time.

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Depth profile of mass density of vertical alignment film was investigated by X-ray reflectivity, in order to characterize side chains at film surface for vertical alignment of liquid crystals. Existence thin and low density top layer at surface of polyimide film, which was considered to be side chains, was clearly detected. Furthermore, existence of high density layer just below side chain layer was also found, and it is suggested that backbone chain ordering at film surface. Effect of rubbing on VA film was not detected. However, density growth by annealing just below side chain layer of rubbed VA film suggests more ordered backbone chain alignment induced by rubbing.

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Backlight dimming techniques have been researched much to obtain high power saving on display modules, especially those which are based on LCD. The use of LED as a light source in a backlight module has opened a wider chance to perform local dimming as an improvement of a conservative global dimming approach. However, local dimming techniques are sometimes observed to obtain worse performance than global dimming ones in terms of power saving or image fidelity. We observed that even some of their results show visible artifacts. In this paper, we propose a novel backlight dimming technique called hybrid dimming, which combines local and global dimming approaches effectively. We do local dimming to obtain the initial backlight levels while calculating its SSIM index, which is a human visual system-aware image quality metric. We then make sure that these backlight levels don't exceed the ones obtained from a human visual system-aware global dimming with similar image fidelity. As a result, our proposed method can gain better power saving than a human visual system-aware global dimming and prior local dimming techniques, while making little difference in the image fidelity and suppressing visible block artifacts in the results. Experimental results showed that the proposed technique can achieve up to 14, 2.2, and 2.4 times higher power saving ratio than human visual system-aware global dimming and two well-designed local dimming techniques, respectively.

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The color appearance model gives us the proper brightness information and optimized display conditions for various viewing surroundings. However on conditions of low-level illumination or low background reflectivity, the performance of brightness estimation is relatively poor. Therefore, through our psychophysical experiments, we investigated the state of visual luminance adaptation for comparing single adaptations and mixed adaptations under a complex viewing field, and we also investigated background adaptation degrees and exponential nonlinearity factors for mixed adaptation models. It provides more accurate brightness predictions according to different adapting luminance, which is decided from object and background luminance.

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A 24-GHz continuous wave (CW) radar with three vertically switched beam antennas for monitoring different range segments has been newly proposed and developed as a means to detect intruders in a fan-shaped ground area with 90degs. in azimuth and over 10m in range. This radar can detect moving targets and measure their positions from a tampering-proof height of about 5m by taking advantage of a two-frequency-CW modulation technique and monopulse scheme used to achieve the wide azimuth coverage. The radar module consists of microstrip-patch planar antennas and monolithic microwave integrated circuits (MMICs), which are placed on the opposite side of a single metal plate to attain compact size and lower cost. An experimental radar successfully detected a human intruder with a position accuracy of 50cm when moving at 1.4m/s.

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This paper presents an adaptive FFE/DFE receiver with an algorithm that measures the data-dependent jitter. The proposed adaptive algorithm determines the compensation level by measuring the input data-dependent jitter. The adaptive algorithm is combined with a clock and data recovery phase detector. The receiver is fabricated in with 0.13µm CMOS technology, and the compensation range of equalization is up to 26dB at 2GHz. The test chip is verified for a 40 inch FR4 trace and a 53cm flexible printed circuit channel. The receiver occupies an area of 440µm × 520µm and has a power dissipation of 49mW (excluding the I/O buffers) from a 1.2V supply.

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A 12Gb/s 10-level pulse amplitude modulation (PAM) serial-link transmitter was implemented using a 0.18µm CMOS process. The proposed 10-PAM transmitter achieves a channel efficiency of 4bit/symbol by dual-mode amplitude modulations using 10 differential-mode levels and 3 common-mode levels. The measured maximum data-rate was 12Gb/s over 0.7-m cable and 2-cm printed circuit board (PCB) traces. The entire transmitter consumes 432mW such that the figure of merit of the transmitter is 36pJ/bit. The present work demonstrates the greater channel efficiency of 4bit/symbol than the currently reported multi-level PAM transmitters.

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Dielectric rod arrays in a metallic waveguide alter the propagation modes and group velocities of electromagnetic waves. We have focused on TE₃₀-to-TE₁₀ mode converters and investigated how their behavior varies with frequency. A mode converter is proposed that passes the TE₁₀ mode at frequencies lower than 2ƒ_c, and converts the TE₃₀ mode into the TE₁₀ mode for frequencies higher than 3ƒ_c.

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A 200kS/s 10-bit successive approximation (SA) analog-to-digital converter (ADC) with a rail-to-rail input signal is proposed for acquiring biosignals such as EEG and MEG signals. A split-capacitor-based digital-to-analog converter (SC-DAC) is used to reduce the power consumption and chip area. The SC-DAC's linearity is improved by using dummy capacitors and a small bootstrapped analog switch with a constant on-resistance, without increasing its area. A time-domain comparator with a replica circuit for clock feed-through noise compensation is designed by using a highly differential digital architecture involving a small area. Its area is about 50% less than that of a conventional time-domain comparator. The proposed SA ADC is implemented by using a 0.18-µm 1-poly 6-metal CMOS process with a 1V supply. The measured DNL and INL are +0.44/-0.4 LSB and +0.71/-0.62 LSB, respectively. The SNDR is 55.43dB for a 99.01kHz analog input signal at a sampling rate of 200kS/s. The power consumption and core area are 5µW and 0.126mm², respectively. The FoM is 47fJ/conversion-step.

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In this letter, an improved triple-tunable frequency synthesizer structure to achieve both high frequency resolution and fast switching speed without degradation of spurious signals (spurs) level performance is proposed. According to this structure, a high performance millimeter-wave frequency synthesizer with low spurious, low phase noise, and fast switching speed, is developed. This synthesizer driven by the direct digital synthesizer (DDS) AD9956 can adjust the output of a DDS and frequency division ratios of two variable frequency dividers (VFDs) to move the spurious components outside the loop bandwidth of the phase-locked loop (PLL). Moreover, the ADF4252 based microwave PLL can further suppress the phase noise. Experimental results from the implemented synthesizer show that remarkable performance improvements have been achieved.

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A 6-10-GHz broadband low noise amplifier (LNA) and transmitting amplifier (TA) for direct sequence ultra-wideband (DS-UWB) are presented. The LNA and TA are fabricated with the 0.18-µm 1P6M standard CMOS process. The CMOS LNA and TA are checked by on-wafer measurement with the DC supply voltage of 1.5V. From 6-10GHz, the broadband LNA exhibits a noise figure of 5.3-6.2dB, a gain of 11-13.8dB, a P_1dB of -15.7--10.8dBm, a IIP3 of -5.5--1dBm, a DC power consumption of 12mW, and an input/output return loss higher than 11/12dB, respectively. From 6-10GHz, the broadband TA exhibits a gain of 7.6-10.5dB, a OP_1dB of 2.8-6.1dBm, a OIP3 of 12.3-15.1dBm, and a PAE of 8.8-17.6% @ OP_1dB, and a η of 9.7-21.1% @ OP_1dB, and an input/output return loss higher than 6.8/3.2dB, respectively.

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