TY - JOUR A1 - Miyamoto, Ko-ichiro A1 - Wagner, Torsten A1 - Mimura, Shuhei A1 - Kanoh, Shin`ichiro A1 - Yoshinobu, Tatsuo A1 - Schöning, Michael Josef T1 - Constant-phase-mode operation of the light-addressable potentiometric sensor JF - Procedia Chemistry. 1 (2009), H. 1 Y1 - 2009 SN - 1876-6196 N1 - Proceedings of the Eurosensors XXIII conference ; Eurosensors 23 SP - 1487 EP - 1490 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Miyamoto, Ko-ichiro A1 - Sugawara, Yuri A1 - Kanoh, Shin´ichiro A1 - Yoshinobu, Tatsuo A1 - Wagner, Torsten A1 - Schöning, Michael Josef T1 - Image correction method for the chemical imaging sensor JF - Sensors and Actuators B: Chemical. 144 (2010), H. 2 Y1 - 2010 N1 - 22nd International Conference on Eurosensors - Dresden, Germany, 7-10 September 2008 ; Eurosensors ; (22, 2008, Dresden) SP - 344 EP - 348 ER - TY - JOUR A1 - Wagner, Torsten A1 - Werner, Frederik A1 - Miyamoto, Ko-ichiro A1 - Ackermann, Hans-Josef A1 - Yoshinobu, Tatsuo A1 - Schöning, Michael Josef T1 - FPGA-based LAPS device for the flexible design of sensing sites on functional interfaces JF - Physica Status Solidi (A). 207 (2010), H. 4 Y1 - 2010 SN - 1862-6300 N1 - Special Issue: Engineering of Functional Interfaces EnFI 2009 SP - 844 EP - 849 ER - TY - JOUR A1 - Wagner, Torsten A1 - Miyamoto, Ko-ichiro A1 - Schöning, Michael Josef A1 - Yoshinobu, Tatsuo T1 - Novel combination of digital light processing (DLP) and light-addressable potentiometric sensors (LAPS) for flexible chemical imaging JF - Procedia Engineering. 5 (2010) Y1 - 2010 SN - 1877-7058 N1 - Eurosensor XXIV Conference SP - 520 EP - 523 ER - TY - JOUR A1 - Miyamoto, Ko-ichiro A1 - Kaneko, Kazumi A1 - Matsuo, Akira A1 - Wagner, Torsten A1 - Kanoh, Shin`ichiro A1 - Schöning, Michael Josef A1 - Yoshinobu, Tatsuo T1 - Miniaturized chemical imaging sensor system using an OLED display panel JF - Procedia Engineering. 5 (2010) Y1 - 2010 SN - 1877-7058 N1 - Eurosensor XXIV Conference SP - 516 EP - 519 ER - TY - JOUR A1 - Miyamoto, Ko-ichiro A1 - Wagner, Torsten A1 - Yoshinobu, Tatsuo A1 - Kanoh, Shin`ichiro A1 - Schöning, Michael Josef T1 - Phase-mode LAPS and its application to chemical imaging JF - Sensors and Actuators B: Chemical. 154 (2011), H. 1 Y1 - 2011 SN - 1873-3077 SP - 28 EP - 32 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Miyamoto, Ko-ichiro A1 - Yoshida, Midori A1 - Sakai, Taito A1 - Matsuzaka, Atsushi A1 - Wagner, Torsten A1 - Kanoh, Sanoh A1 - Yoshinobu, Tatsuo A1 - Schöning, Michael Josef T1 - Differential setup of light-addressable potentiometric sensor with an enzyme reactor in a flow channel JF - Japanese Journal of Applied Physics. 50 (2011) Y1 - 2011 SN - 0021-4922 SP - 04DL08-1 EP - 04DL08-5 PB - Japan Society of Applied Physics CY - Bristol ER - TY - JOUR A1 - Miyamoto, Ko-ichiro A1 - Wagner, Torsten A1 - Yoshinobu, Tatsuo A1 - Kanoh, Shin`ichiro A1 - Schöning, Michael Josef T1 - Phase-mode operation of FDM-LAPS JF - Sensor letters Y1 - 2011 SN - 1546-1971 VL - 9 IS - 2 SP - 691 EP - 694 PB - American Scientific Publishers CY - Stevenson Ranch, Calif. ER - TY - JOUR A1 - Miyamoto, Ko-ichiro A1 - Wagner, Torsten A1 - Mimura, Shuhei A1 - Kanoh, Shiníchiro A1 - Yoshinobu, Tatsuo A1 - Schöning, Michael Josef T1 - Constant-phase-mode operation of the light-addressable potentiometric sensor JF - Sensors and Actuators B: Chemical. 154 (2011), H. 2 Y1 - 2011 SN - 1873-3077 N1 - EUROSENSORS XXIII SP - 119 EP - 123 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Wagner, Torsten A1 - Miyamoto, Ko-ichiro A1 - Shigihara, Noriko A1 - Schöning, Michael Josef A1 - Yoshinobu, Tatsuo T1 - Microfluidic systems with free definable sensor spots by an integrated light-addressable potentiometric sensor JF - Procedia Engineering. 25 (2011) Y1 - 2011 SN - 1877-7058 N1 - EurosensorsXXV ; Proc. Eurosensors XXV, September 4-7, 2011, Athens, Greece SP - 791 EP - 794 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Werner, Frederik A1 - Wagner, Torsten A1 - Miyamoto, Ko-ichiro A1 - Yoshinobu, Tatsuo A1 - Schöning, Michael Josef T1 - High speed and high resolution chemical imaging based on a new type of OLED-LAPS set-up JF - Procedia Engineering. 25 (2011) Y1 - 2011 SN - 1877-7058 N1 - EurosensorsXXV ; Proc. Eurosensors XXV, September 4-7, 2011, Athens, Greece SP - 346 EP - 349 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Werner, Frederik A1 - Wagner, Torsten A1 - Miyamoto, Ko-ichiro A1 - Yoshinobu, Tatsuo A1 - Schöning, Michael Josef T1 - High speed and high resolution chemical imaging based on a new type of OLED-LAPS set-up JF - Sensors and Actuators B: Chemical N2 - Light-addressable potentiometric sensors (LAPS) are field-effect-based sensors. A modulated light source is used to define the particular measurement spot to perform spatially resolved measurements of chemical species and to generate chemical images. In this work, an organic-LED (OLED) display has been chosen as a light source. This allows high measurement resolution and miniaturisation of the system. A new developed driving method for the OLED display optimised for LAPS-based measurements is demonstrated. The new method enables to define modulation frequencies between 1 kHz and 16 kHz and hence, reduces the measurement time of a chemical image by a factor of 40 compared to the traditional addressing of an OLED display. Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.snb.2011.12.102 SN - 0925-4005 N1 - Part of special issue "Selected Papers presented at Eurosensors XXV" VL - 175 SP - 118 EP - 122 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Miyamoto, Ko-ichiro A1 - Kaneko, Kazumi A1 - Matsuo, Akira A1 - Wagner, Torsten A1 - Kanoh, Shiníchiro A1 - Schöning, Michael Josef A1 - Yoshinobu, Tatsuo T1 - Miniaturized chemical imaging sensor system using an OLED display panel JF - Sensors and Actuators B: Chemical N2 - The chemical imaging sensor is a semiconductor-based chemical sensor that can visualize the two-dimensional distribution of specific ions or molecules in the solution. In this study, we developed a miniaturized chemical imaging sensor system with an OLED display panel as a light source that scans the sensor plate. In the proposed configuration, the display panel is placed directly below the sensor plate and illuminates the back surface. The measured area defined by illumination can be arbitrarily customized to fit the size and the shape of the sample to be measured. The waveform of the generated photocurrent, the current–voltage characteristics and the pH sensitivity were investigated and pH imaging with this miniaturized system was demonstrated. KW - LAPS KW - Light-addressable potentiometric sensor KW - Chemical imaging sensor KW - Organic light-emitting diode display Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.snb.2011.02.029 SN - 0925-4005 N1 - Part of special issue "Eurosensors XXIV, 2010" VL - 170 SP - 82 EP - 87 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Miyamoto, Ko-ichiro A1 - Hirayama, Yuji A1 - Wagner, Torsten A1 - Schöning, Michael Josef A1 - Yoshinobu, Tatsuo T1 - Visualization of enzymatic reaction in a microfluidic channel using chemical imaging sensor JF - Electrochimica acta Y1 - 2013 SN - 1873-3859 (E-Journal); 0013-4686 (Print) SP - Publ. online PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Itabashi, Akinori A1 - Kosaka, Naoki A1 - Miyamoto, Ko-ichiro A1 - Wagner, Torsten A1 - Schöning, Michael Josef T1 - High-speed chemical imaging system based on front-side-illuminated LAPS JF - Sensors and actuators B: Chemical N2 - The chemical imaging sensor is a semiconductor-based chemical sensor that can visualize the spatial distribution of specific ions on the sensing surface. The conventional chemical imaging system based on the light-addressable potentiometric sensor (LAPS), however, required a long time to obtain a chemical image, due to the slow mechanical scan of a single light beam. For high-speed imaging, a plurality of light beams modulated at different frequencies can be employed to measure the ion concentrations simultaneously at different locations on the sensor plate by frequency division multiplex (FDM). However, the conventional measurement geometry of back-side illumination limited the bandwidth of the modulation frequency required for FDM measurement, because of the low-pass filtering characteristics of carrier diffusion in the Si substrate. In this study, a high-speed chemical imaging system based on front-side-illuminated LAPS was developed, which achieved high-speed spatiotemporal recording of pH change at a rate of 70 frames per second. Y1 - 2013 U6 - http://dx.doi.org/10.1016/j.snb.2013.03.016 SN - 1873-3077 VL - 182 SP - 315 EP - 321 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Miyamoto, Ko-ichiro A1 - Ichimura, Hiroki A1 - Wagner, Torsten A1 - Schöning, Michael Josef A1 - Yoshinobu, Tatsuo T1 - Chemical imaging of the concentration profile of ion diffusion in a microfluidic channel JF - Sensors and actuators. B: Chemical N2 - The chemical imaging sensor is a device to visualize the spatial distribution of chemical species based on the principle of LAPS (light-addressable potentiometric sensor), which is a field-effect chemical sensor based on semiconductor. In this study, the chemical imaging sensor has been applied to investigate the ion profile of laminar flows in a microfluidic channel. The chemical images (pH maps) were collected in a Y-shaped microfluidic channel while injecting HCl and NaCl solutions into two branches. From the chemical images, it was clearly observed that the injected solutions formed laminar flows in the channel. In addition, ion diffusion across the laminar flows was observed, and the diffusion coefficient could be derived by fitting the pH profiles to the Fick's equation. Y1 - 2013 U6 - http://dx.doi.org/10.1016/j.snb.2013.04.057 SN - 1873-3077 (E-Journal); 0925-4005 (Print) N1 - Part of special issue "Selected Papers from the 26th European Conference on Solid-State Transducers" VL - 189 SP - 240 EP - 245 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Miyamoto, Ko-ichiro A1 - Itabashi, Akinori A1 - Wagner, Torsten A1 - Schöning, Michael Josef A1 - Yoshinobu, Tatsuo T1 - High-speed chemical imaging inside a microfluidic channel JF - Sensors and actuators. B: Chemical N2 - In this study, a high-speed chemical imaging system was developed for visualization of the interior of a microfluidic channel. A microfluidic channel was constructed on the sensor surface of the light-addressable potentiometric sensor (LAPS), on which the ion concentrations could be measured in parallel at up to 64 points illuminated by optical fibers. The temporal change of pH distribution inside the microfluidic channel was recorded at a maximum rate of 100 frames per second (fps). The high frame rate allowed visualization of moving interfaces and plugs in the channel even at a flow velocity of 111 mm/s, which suggests the feasibility of plug-based microfluidic devices for flow-injection analysis (FIA). Y1 - 2014 U6 - http://dx.doi.org/10.1016/j.snb.2013.12.090 SN - 1873-3077 (E-Journal); 0925-4005 (Print) VL - 194 SP - 521 EP - 527 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Guo, Yuanyuan A1 - Seki, Kosuke A1 - Miyamoto, Ko-ichiro A1 - Wagner, Torsten A1 - Schöning, Michael Josef A1 - Yoshinobu, Tatsuo T1 - Novel photoexcitation method for light-addressable potentiometric sensor with higher spatial resolution JF - Applied physics express : APEX N2 - A novel photoexcitation method for the light-addressable potentiometric sensor (LAPS) is proposed to achieve a higher spatial resolution of chemical images. The proposed method employs a combined light source that consists of a modulated light probe, which generates the alternating photocurrent signal, and a ring of constant illumination surrounding it. The constant illumination generates a sheath of carriers with increased concentration which suppresses the spread of photocarriers by enhanced recombination. A device simulation was carried out to verify the effect of constant illumination on the spatial resolution, which demonstrated that a higher spatial resolution can be obtained. Y1 - 2014 U6 - http://dx.doi.org/10.7567/APEX.7.067301 SN - 1882-0786 (E-Journa); 1882-0778 (Print) VL - 7 IS - 6 SP - 067301-4 PB - IOP CY - Bristol ER - TY - JOUR A1 - Guo, Yuanyuan A1 - Miyamoto, Ko-ichiro A1 - Wagner, Torsten A1 - Schöning, Michael Josef A1 - Yoshinobu, Tatsuo T1 - Theoretical study and simulation of light-addressable potentiometric sensors JF - Physica status solidi (A) : applications and materials N2 - The light-addressable potentiometric sensor (LAPS) is a semiconductor-based potentiometric sensor using a light probe with an ability of detecting the concentration of biochemical species in a spatially resolved manner. As an important biomedical sensor, research has been conducted to improve its performance, for instance, to realize high-speed measurement. In this work, the idea of facilitating the device-level simulation, instead of using an equivalent-circuit model, is presented for detailed analysis and optimization of the performance of the LAPS. Both carrier distribution and photocurrent response have been simulated to provide new insight into both amplitude-mode and phase-mode operations of the LAPS. Various device parameters can be examined to effectively design and optimize the LAPS structures and setups for enhanced performance. Y1 - 2014 U6 - http://dx.doi.org/10.1002/pssa.201330354 SN - 0031-8965 VL - 211 IS - 6 SP - 1467 EP - 1472 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Guo, Yuanyuan A1 - Miyamoto, Ko-ichiro A1 - Wagner, Torsten A1 - Schöning, Michael Josef A1 - Yoshinobu, Tatsuo T1 - Device simulation of the light-addressable potentiometric sensor for the investigation of the spatial resolution JF - Sensors and actuators B: Chemical N2 - As a semiconductor-based electrochemical sensor, the light-addressable potentiometric sensor (LAPS) can realize two dimensional visualization of (bio-)chemical reactions at the sensor surface addressed by localized illumination. Thanks to this imaging capability, various applications in biochemical and biomedical fields are expected, for which the spatial resolution is critically significant. In this study, therefore, the spatial resolution of the LAPS was investigated in detail based on the device simulation. By calculating the spatiotemporal change of the distributions of electrons and holes inside the semiconductor layer in response to a modulated illumination, the photocurrent response as well as the spatial resolution was obtained as a function of various parameters such as the thickness of the Si substrate, the doping concentration, the wavelength and the intensity of illumination. The simulation results verified that both thinning the semiconductor substrate and increasing the doping concentration could improve the spatial resolution, which were in good agreement with known experimental results and theoretical analysis. More importantly, new findings of interests were also obtained. As for the dependence on the wavelength of illumination, it was found that the known dependence was not always the case. When the Si substrate was thick, a longer wavelength resulted in a higher spatial resolution which was known by experiments. When the Si substrate was thin, however, a longer wavelength of light resulted in a lower spatial resolution. This finding was explained as an effect of raised concentration of carriers, which reduced the thickness of the space charge region. The device simulation was found to be helpful to understand the relationship between the spatial resolution and device parameters, to understand the physics behind it, and to optimize the device structure and measurement conditions for realizing higher performance of chemical imaging systems. Y1 - 2014 U6 - http://dx.doi.org/10.1016/j.snb.2014.08.016 SN - 1873-3077 (E-Journal); 0925-4005 (Print) VL - 204 SP - 659 EP - 665 PB - Elsevier CY - Amsterdam ER -