Author
Takashi Iwata
Bio: Takashi Iwata is an academic researcher from Kyushu University. The author has contributed to research in topics: Liquid crystal & Phase (matter). The author has an hindex of 9, co-authored 17 publications receiving 2167 citations.
Topics: Liquid crystal, Phase (matter), Isotropy, Dog clutch, Clutch
Papers
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01 May 2007
TL;DR: In this paper, the authors demonstrate the sufficiently large electric field-induced birefringence and the micro-second response of the polymer-stabilized blue phases and the induced-isotropic phases without any surface treatment.
Abstract: Blue phases have two major advantages over commonly used nematic phases:1) the response is much faster, 2) the zero-electric field state is optically isotropic. We demonstrate the sufficiently large electric field-induced birefringence and the micro-second response of the polymer-stabilized blue phases and the induced-isotropic phases without any surface treatment.
1,030 citations
01 Jun 2009
TL;DR: In this paper, the phase behavior and electro-optical Kerr effect of the optically isotropic liquid crystal composites, which require no surface treatment for device fabrication, were presented.
Abstract: In this paper, we present the phase behavior and electro-optical Kerr effect of the optically isotropic liquid crystal composites, which require no surface treatment for device fabrication. Anomalously large Kerr constant, more than 10−8 mV−2 and fast response, less than sub-milli-second were observed at a room temperature.
980 citations
TL;DR: In this paper, the authors investigated the kinetics of cross-linking copolymerization of acrylate and methacrylate-monomers in a liquid crystal blue phase to prepare the polymer-stabilized blue phase based on dynamic mechanical analysis.
Abstract: Kinetics of cross-linking copolymerization of acrylate- and methacrylate-monomers in a liquid crystal blue phase to prepare the polymer-stabilized blue phase were investigated based on dynamic mechanical analysis. Although the polymerization rate of methacrylate-monomers is generally much lower than that of acrylate-ones, we found that a methacrylate cross-linker enhanced the cross-linking copolymerization and an acrylate one suppressed it when acrylate- and methacrylate-monomers were copolymerized with cross-linking. The order of copolymerization rate of monofunctional monomer/difunctional one was monoacrylate (mA)/dimethacrylate (dMA), mA/diacrylate (dA), monomethacrylate (mMA)/dMA, and mMA/dA. The synchrotron small-angle X-ray scattering measurements were carried out to evaluate the aggregated structure of polymer networks in the polymer-stabilized blue phase and found the regular polymer structure corresponding to the disclination lattice of the blue phase, indicating that the polymers were segregated preferentially in the disclination cores. The degree of the regularity of polymer networks was opposite order of copolymerization rate. We obtained a good correlation among the polymerization kinetics, the mechanical elastic constant and the polymer aggregation structure in the polymer-stabilized blue phases, leading to a novel strategy to control the structure and the performance of the polymer-stabilized blue phases.
53 citations
TL;DR: In this paper, a cross-linker with a chiral structure was used to increase the magnitude of the Kerr constant of polymer-stabilised blue phase (PSBP) for display devices.
Abstract: Polymer-stabilised blue phase (PSBP) is one of the most promising materials for display devices because of its superior electro-optical properties compared with conventional nematics. However, the application of the PSBP has a serious practical issue in that the driving voltage required is too high to drive with thin film transitors, that is, the magnitude of the Kerr constant of PSBPs is insufficient. We present a useful method for increasing the Kerr constant based on the control of polymer aggregation structure using a cross-linker with a chiral structure. The director distortion arising from polymer networks in the PSBP seems to be responsible for the resulting improvement.
24 citations
TL;DR: In this article, an optically isotropic liquid crystal display (LCD) was demonstrated with a sub-millisecond response time and a continuous greyscale capability.
Abstract: We demonstrate an intriguing liquid crystal display (LCD) mode that comprises an optically isotropic LC composite incorporating in-plane electric field geometry. No surface treatment, such as rubbing, is required to fabricate the LCD mode because it is based on an isotropic state. The measured response time is of submillisecond order. This rapid response originates from the local reorientation of molecules in small LC clusters as well as from strong polymer stabilization. The LCD mode has several unique features such as fast response, continuous greyscale capability and a high contrast ratio.
23 citations
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Patent•
01 Aug 2008
TL;DR: In this article, the oxide semiconductor film has at least a crystallized region in a channel region, which is defined as a region of interest (ROI) for a semiconductor device.
Abstract: An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.
1,501 citations
Patent•
25 Sep 2013
TL;DR: In this paper, a connection terminal portion is provided with a plurality of connection pads which are part of the connection terminal, each of which includes a first connection pad and a second connection pad having a line width different from that of the first one.
Abstract: An object of the present invention is to decrease the resistance of a power supply line, to suppress a voltage drop in the power supply line, and to prevent defective display. A connection terminal portion includes a plurality of connection terminals. The plurality of connection terminals is provided with a plurality of connection pads which is part of the connection terminal. The plurality of connection pads includes a first connection pad and a second connection pad having a line width different from that of the first connection pad. Pitches between the plurality of connection pads are equal to each other.
1,136 citations
Patent•
17 Jan 2006
TL;DR: In this article, the authors propose a technique by which a pattern of wirings or the like which is partially constitutes a semiconductor device or a display device can be formed with a desired shape with controllability.
Abstract: To provide a semiconductor device and a display device which can be manufactured through a simplified process and the manufacturing technique. Another object is to provide a technique by which a pattern of wirings or the like which is partially constitutes a semiconductor device or a display device can be formed with a desired shape with controllability.
1,043 citations
01 Jun 2009
TL;DR: In this paper, the phase behavior and electro-optical Kerr effect of the optically isotropic liquid crystal composites, which require no surface treatment for device fabrication, were presented.
Abstract: In this paper, we present the phase behavior and electro-optical Kerr effect of the optically isotropic liquid crystal composites, which require no surface treatment for device fabrication. Anomalously large Kerr constant, more than 10−8 mV−2 and fast response, less than sub-milli-second were observed at a room temperature.
980 citations
Patent•
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22 Jun 2009
TL;DR: In this paper, a gate-insulated thin-film transistor with a halogen block in between the blocking layer and a gate insulator is described. But the block is not used to prevent the transistor from being contaminated with impurities such as alkali ions.
Abstract: A gate-insulated thin film transistor is disclosed. One improvement is that the thin film transistor is formed on a substrate through a blocking layer in between so that it is possible to prevent the transistor from being contaminated with impurities such as alkali ions which exist in the substrate. Also, a halogen is added to either or both of the blocking layer and a gate insulator of the transistor in order that impurities such as alkaline ions, dangling bonds and the like can be neutralized, therefore, the reliability of the device is improved.
348 citations