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Touch screen displays have been a subject of growing interest in recent years due to the significant usability benefits they provide for portable electronic devices ranging from mobile phones to tablet PCs. In this paper we report the preparation of index-matched ITO-PET films by depositing thin films of SiNx, SiOx and ITO on hard coated polyethylene terephthalate (PET) film utilizing roll-to-roll sputtering system.

Currently, substrate thin film solar cells with Cu(In,Ga)Se2(CIS) absorbers yield conversion efficiencies of up 20.4%, the highest published efficiency of CIS superstrate thin film solar cells is 12.8%. It is the maximum efficiency when composition is as follow; Cu, In and Se was 1, 1 and 2. The maximum efficiency of CIS superstrate thin film solar cell is smaller than that of CIS substrate thin film solar cell, but manufacturing cost of CIS superstrate is lower than that of CIS substrate since the reduce of the manufacturing process. In addition, CIS absorber layer is fabricated through binary phases to reduce the process temperature and processing price. In this study, CIS superstrate thin film solar cell was fabricated to reduce the device manufacturing cost and CIS absorber layer was deposited by the binary phases. By using substrate (Sodalime Glass,SLG), window layer(i-ZnO, Al:ZnO)were deposited on n-type transparent electrode layer in the upper part. CIS absorber was respectively deposited by In2Se3...

The preparation method of encapsulating paste containing YAG phosphor and red quantum dot (QD) in silicone resin and the structure of phosphor layers were studied from the view point of improving both the efficiency and color rendering index (CRI) of the phosphor converted white LED (pcWLED). The addition of red phosphor or red QD in addition to the YAG phosphor could increase CRI of the pcWLED, but the efficiency was decreased. The pcWLED packaged with the encapsulant where the red QD was mixed in advance with the part of the silicone resin and mixed again with the YAG phosphor dispersed the remaining in silicone resin exhibited higher CRI and efficiency than the one packaged with one pot mixture of YAG and red QDs. The pcWLEDs made by silicone encapsulant with YAG phosphor and red QD at the ratio of YAG:QD = 5.0:0.5wt% exhibited that both efficiency and color rendering index could be increased at same time by adopting YAG phosphor and QD encapsulation in a layer-by-layer structure on top of InGaN LED chip.

The chip on board (COB) types LED modules were fabricated by using metal core printed circuit board (mcPCB), aluminium oxide (Al2O3) and aluminium nitride (AlN) as submounts of LED chips. The radiant flux of the LEDs exhibited slight difference in terms of the LED chip bonding process in which eutectic bonding gave higher radiant flux than Ag epoxy bonding in both AlN and Al2O3 substrates. However the LED modules fabricated on AlN ceramic substrate exhibited higher radiant flux than the one on Al2O3 substrate at high current due to more effective heat dissipation in case of AlN substrate. The WLED modules encapsulated with YAG phosphor and red QD by layer-by-layer mode showed both high total luminous flux and high color rendering index.

This study was carried out to analyze the dynamic characteristics of laser tailor-welded blanks (TWBs) made of dissimilar materials. The analysis was performed using Hyper Works 10.0 with Solver LS-DYNA v.971. 2D-Shell was used as the modeling element, and the number of elements and nodes was 35,641 and 36,561, respectively. The impact speed was 10 km/h. To analyze the impact characteristics according to the height of the weld line for the upper and lower parts of the center pillar, the length of the lower part was set as 300 and 400 mm. When the lower part was made of SPFC980 steel with a length of 300 mm, the deformation was the smallest and the absorbed energy of the impact force was the largest. On based the lower part of center pillar, the position of TWB shows the shorter and the better value. In other words, the performance depended on the proportion of the upper part made of high-strength SABC1470 steel. A lower part made of SPFH590 steel showed large deformation. In contrast, a lower part made of SPFC980 steel showed significantly lesser deformation. Therefore, the impact performance of a lower part made of SPFC980 steel with a length of 300 mm showed the best analysis result.

A humanoid robot hand with one thumb and two fingers has been developed. Each finger has the specially designed compact joints, called "MEC Joint", which convert the rotation of a motor to the swing motion of a pendulum. The robot hand with the MEC Joints is compact and relatively light but strong enough to grasp objects in the same manner as human being does in daily activities. In this paper the kinematic model and the torque characteristics of the MEC Joint are presented and compared with the results of the dynamic simulation and the dynamometer test. The dynamic behavior of the thumb and two fingers with MEC Joints are also presented by computer simulation.

In order to ensure long lifetime and stable light output of LEDs the thermal performance parameters need to be designed in the LED chip package and module level, which include such items as heat sink structure and materials, interface materials and substrates. In this work we used aluminium nitride(AlN) as submount of LED chips and made chip on board(COB) type LED module. The effect of different silver(Ag) epoxy bonding materials and bonding methods on the performance of LED module were examined. The effect of addition of red quantum dot(QD) on the performance of white LED was also studied.

In this paper we studied switchable mirrors for application to transparent flat panel displays. The typical structure of switchable mirror has configuration of MgNi/Pd/Ta2O5/HxWO3/ITO. In this study photocatalyst layer (TiO2 or Nb2O5) was used between Pd and Ta2O5 layers. These layers were prepared by RF magnetron sputtering method utilizing TiO2 and Nb2O5 targets under various conditions and their electrochromic properties were investigated by using FE-SEM, EDAX and Nano View system. The transmittances of the Nb2O5 and the TiO2 thin films, could be optimized in the switchable mirror as photocatalyst layer, where they were deposited under the power of 80 W and 70 W, respectively, by the RF magnetron sputter. The characteristics of Nb2O5 and TiO2 transmittance are the outstanding at 80 W, 70 W respectively.

A series of polyimide (PI) and copolyimide (Co-PI) films were prepared by two-step imidization processes from the poly(amicacid) precursors. The color and visible light transmission of the Co-PI films were much better than those of the general Kapton type PI film mainly due to the decrease of the charge transfer complex formation by the presence of the CF3 groups both in the aromatic diamine and dianhydride monomers. In the ITO thin film deposition and subsequent OLED device fabrication, the thermal and mechanical properties of the Co-PI films were more important than the optical property of the Co-PI films.

Flexible white OLED (organic light emitting diode) is a subject of intense research due to its application as versatile lightings for housing and flexible backlight unit for TFT-LCD. In order to make flexible OLED, flexible transparent conductor substrate is required which can replace ITO-glass used in current OLED devices. Another important point is a good gas barrier property of the flexible ITO-film, since the water vapor transmission rate (WVTR) of polymer film is much higher than that of ITO-glass and the life time of OLED device is very sensitive to the transmitted water vapor. In this work, a wet process of forming gas barrier layer on polyethersulfone (PES) film was studied utilizing spin coating of polysilazane solution and thermal conversion to thin SiO2 barrier layer. The flexible white OLED fabricated with this ITO-SiO2 (polysilazane)-PES substrate exhibited about equal power and current efficiencies to the OLED made with ITO-glass.

We introduce indium zinc oxide (IZO) thin films grown at room temperature by using a low-frequency (LF) 60 Hz magnetron sputtering system. The flexible substrates are PES, PET and PC. The optical, electrical and structural properties of IZO films on flexible substrates were investigated. The alloy target was In2O3:ZnO (90:10 wt%) with a diameter of 3 inch and thickness of 5 mm. The vacuum chamber was evacuated down to pressure 5 × 10−6 torr prior to deposition. The flow rates of argon gas (99.999 %) were kept at a constant value of 30 sccm by a mass flow controller(MFC). The discharges were performed by power of 300 V, 310 V, 320 V. They have low sheet resistance of about 30 Ω/sq., high transmittance of over 85 % in the range of 400–700 nm. Also they showed good band gap of about 3.43 eV on polyethersulfone (PES) substrates, 3.50 eV on polyethylene terephthalate (PET) and 3.30 eV on polycarbonate (PC). The experimental results imply that the films with good qualities in surface morphology, transmittance a...

This study provides the electrical model of combustible catalytic gas sensor. Physical characteristics such as thermal behavior, resistance change were included in this model. The finite element method analysis for sensor device structure showed that the thermal behavior of sensor is expressed in a simple electrical equivalent circuit that consists of a resistor, a capacitor and a current source. This thermal equivalent circuit interfaces with real electrical circuit using two parts. One is `power to heat` converter. The other is temperature dependent variable resistor. These parts realized with the analog behavior devices of the SPICE library. The gas response tendency was represented from the mass transferring limitation theory and the combustion theory. In this model, Gas concentration that is expressed in voltage at the model, is converted to heat and is flowed to the thermal equivalent circuit. This model is tested in several circuit simulations. The resistance change of device, the delay time due to thermal capacity, the gas responses output voltage that are calculated from SPICE simulations correspond well to real results from measuring in electrical circuits. Also good simulation result can be produced in the more complicated circuit that includes amplifier, bios circiut, buffer part.

Many works to improve the stability and sensitivity of metal-oxide based gas sensors have been carried out during last several decades. As one of stability problems, we can present an example that the resistance alters to some extent when the devices are exposed to the normal air, which becomes an obstacle to its practical use. In this paper, we proposed a new type of micro gas sensor with single electrode for improving stability and sensitivity. Generally, metal-oxide gas sensors have two electrodes for heating and sensing. But this new type sensor has only a single electrode by depositing a sensing metal-oxide material onto the heating electrode. Owing to this structure, the sensor output signal in ambient condition could be very stable unlikely to metal-oxide gas sensor. As a result of CO gas sensing characteristics, this sensor shows 80 mV voltage output for 1000 ppm and linearity for ranges (0–250 ppm) of gas concentrations. The deviation of sensor resistance is about 1% for 3 months and a little influence for humidity upto 90% RH.

Optical fiber sensors have been used to detect small amounts of chemical species. In this work, a new thin polymer-clad fiber sensor is developed. Polyaniline is chemically synthesized and thin clad layers of the polymer are easily deposited on optical fiber by dip-coating technique. The optical property of polyaniline as a sensing material is analyzed by UV-Vis-NIR. The light source is stabilized He-Ne laser at 635 nm wavelength with 1 mW power. The light power transmitted through the optical fiber is measured with a spectrophotometer. By selecting a fixed incident angle, variation of transmitted light intensity through the optical fiber can be detected as gas molecules absorbed in the polyaniline clad layer. Among the various gases, the fabricated optical fiber sensor shows good sensitivity to gas. The optical fiber sensors was shown more improved properties than polymer based sensors which measure conductivity changes.

A three electrode type sensor was fabricated. This sensor consists of two parts. One is a tin doped indium oxide (or indium tin oxide: denoted ITO hereafter) film. It was fabricated by the metal thermal oxidation method. This produces a large surface area and low resistivity. So, this film has two functions, a gas sensitive film and an effective heater. The other part is a platinum resistor line covered with oxidized aluminum film. This part is located in the backside of the sensor. It plays three roles. The first is a load resistor for a measuring system. Secondly, it also acts as a heater. Most of the consumed power in the sensor is used as the thermal energy of gas sensing. The last role is catalytic combustible gas sensing in high gas concentrations. In this paper, the fabrication method of gas sensitive ITO film is researched. A complex sensor structure is fabricated. It acts as a hot wire semiconductor sensor at low gas concentration and a combustible catalytic sensor at high concentration.

The tin dioxide (SnO2) films were been prepared by oxidization of tin black film which was deposited by thermal evaporation. This method can be used for a simple and economical fabrication of a SnO2 gas sensor. These films also have an ultra-porous structure and a grain size in the nanometer. The reduction of particle size to nanometers leads to a dramatic improvement in sensitivity. The particle size and structural properties of SnO2 film were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Through the addition of Pt sol as a catalyst, the SnO2/Pt films acquired an appropriate resistance and stable reaction, though sensitivity decreased. The gas sensing characteristics were also investigated using iso-C4H10, CH4, C3H8, and CO gases.

Micro gas sensor with single electrode was proposed for improving stability and sensitivity. Generally, metal oxide gas sensors have two electrodes for heating and sensing. This fabricated new type sensor have only a single electrode by forming a sensing material onto heating electrode. Pt as a heating and sensing electrode was sputtered on glass substrate and a sensing material was thermally evaporated on Pt electrode. was patterned by lift-off process and then thermally oxidized in condition for 1 hr., . The size of fabricated sensor was . As a result of CO gas sensing characteristics, this sensor showed 100 mV change for 1,000 ppm and linearity for wide range() of gas concentrations. And the sensor shows a good recovery characteristics of 1% deviation compared to initial resistance.

In order to get low cost and portability, semiconductor gas sensor need to have low operating temperature and high sensitivity. based sensors which were doped with metal oxide catalysts(, , , and CdO) were fabricated by screen printing method. To improve electrical stability of sensors, the sensors were annealed in at for 2 hours. The doped sensor showed about sensitivity at alcohol 1,000 ppm and have good selectivity to hydrocarbon gas and tobacco odors. The fabricated sensor and PIC-chip were employed for portable alarm system.

WO 3 -based thin film micro-gas sensor was fabricated and the NO x gas sensing as well as electrical properties have been investigated. To obtain the optimal heat distribution, the structure of micro-hot plate was designed from the result of finite element simulation and was prepared by backside etching with KOH solution. The micro-hot plate was made out of N/O/N diaphragm with the thickness of 0.6 μm and area of 1.5×1.5 mm 2 . The power consumption to maintain the device temperature of 300°C was about 60 mW. WO 3 thin film was thermally evaporated on micro-diaphragm. The film exhibited a fast response to NO 2 gas and the relationship between sensitivity and NO 2 concentration showed good linearity in the gas concentration range of 0–30 ppm NO 2 . The sensitivity of micro-gas sensor to NO x was correlated with the microstructure of the thin film.

Two different sensing materials of TiO2–WO3 system with the grain size of nanometer are synthesized; one is a complete 2-nm-sized coprecipitate ((Ti,W)O2) made by sol-coprecipitation of TiCl4 and WCl6, and the other is a complex 8-nm-sized material (TiO2+WO3) by mixing the sol-precipitation of TiCl4 and WCl6. The TiO2–WO3 system showed different characteristics between the coprecipitate and the complex material of TiO2 and WO3. The sensitivity and sorption properties were improved in the coprecipitate. In the coprecipitate, the sensitivity defined as RG/RA, where RG and RA are resistance in gas ambient and in air, respectively, was about 100 for 30 ppm NO2 at 340°C, which is suited for facility combustion furnace. The coprecipitated sensing materials had different resistance and grain size of 6 nm after calcination in air at 600°C for 2 h. The properties of precursor have been investigated by SEM, X-ray diffraction (XRD) and BET analyses.

The parameter study on the grasping characteristics of the humanoid robot hand with a spherical four bar linkage as a finger joint. The humanoid robot hand has one thumb and three fingers, each of which has two spherical four bar linkages, respectively. The humanoid robot hand is 280mm long and less than 2.5kg by weight. The robot hand totally has 13 degree of freedom: one thumb has 4 degree of freedom: each finger has 3 degree of freedom. The spherical four bar linkage was specially designed to rotate like a human finger joint. The robot hand can perform the dexterous motion like a human hand but also the relatively powerful grasping. Two parameters for the grasping characteristics studied in this paper were a diameter of a cylinder to be grasped, the type of grasping. The contact force of the finger joints were calculated for four cases. Numerical analysis had been done in a position control mode by Recurdyn with Matlab/Simulink.

We report on the fabrication and characteristics of micro hot wire sensor with Borofloat glass membrane on diaphragm by using anodic bonding. Borofloat membrane was thermally stable and strong for mechanical stress. The four types of sensing materials SnO/sub 2/, In/sub 2/O/sub 3/ and mixed oxide of adequate ratio with these two type metal oxide semiconductor were prepared by thermal evaporation method and then oxidized at 600 /spl deg/C, 3 hrs. Various sensing materials for NO/sub x/, CO, etc. were prepared. And then the response characteristics were investigated. For mixed oxide semiconductor with Sn and In oxide, these showed the high sensitivity for NO/sub x/ and CO gas. And by using the Borofloat glass substrate, the power consumption was much reduced about 60 mW in condition of the best sensitivity.

The researched sensor at this paper is based on gas sensitive conducting polymer. Some types of conducting polymer have gas sensitivity at room temperature (Matsuguchi et al., 2002). These conducting polymers have several shortages such as low sensitivity. The transistor type gas sensor has been studied for several decades. These sensors are based on metal oxide ceramics such as tin dioxide (Wollenstein et al., 2000 and Popova et al., 1991). We researched a polymer FET gas sensor. The sensor structure is similar to thin film transistor (TFT) one. This sensor can detect very low concentration of ammonia gas. The synthesized polyaniline has the resistance change for ammonia gas. Normally IDT electrode resistor sensor can detect several decade ppm or more ammonia gas. The FET type sensor which has the same polyaniline film can detect 5 ppm of ammonia.

The transparent conductive oxide (TCO) electrode is an important part of organic light-emitting diodes (OLEDs), especially for the OLEDs based on flexible substrate. We fabricated indium tin oxide (ITO)/Ag/ITO multilayer films deposited on polyethylene terephthalate (PET) film by using sputtering technique at room temperature in order to achieve high transmittance and low sheet resistance for application to flexible OLED devices. The OLEDs made with ITO/Ag/ITO multilayer deposited on flexible film exhibited lower operating voltage and higher current efficiency than the OLEDs made with commercial single layer ITO glass substrate.

Transparent conductive ITO/Ag/ITO multilayer thin films were successfully deposited on polyethylene terephthalate (PET) substrates by RF sputtering of ITO layer and DC sputtering of Ag layer at room temperature. Electrical and optical properties of ITO/Ag/ITO multilayer films were strongly dependent on the thickness of Ag thin interlayer. The ITO (50 nm)/Ag (17 nm)/ITO (50 nm) multilayer films deposited on PET substrates exhibited lowest sheet resistance (6.7 Ω/□) and highest transmittance (83.2% at 550 nm). Especially, the sheet resistance of ITO/Ag/ITO multilayer films was superior to those of the commercial ITO (150 nm) films deposited on rigid glass substrates at high temperature. The ITO/Ag/ITO multilayer films coated PET substrate could be a good candidate for application to a transparent conductive oxide (TCO) electrode material for large size flexible OLED devices.

In this study, we have tried the growth of indium tin oxide (ITO) thin films by using low frequency (60 Hz) magnetron sputtering method (LFMSM). Characteristics of ITO thin films deposited at different substrate temperatures (Ts) from room temperature (RT) to 300°C were investigated. The optical transmittance of more than 83% in the visible region and a resistivity of 1.7 × 10−4 Ω·cm have been obtained in the films prepared at a deposition rate of 100 A/min. The peak to valley roughness (Rp-v) value measured by an atomic force microscopy was 4.2–7.8 nm. Structural and electrical characteristics are superior in the films deposited at 250°C. The sheet resistance was 11 Ω/sq for 150-nm-thick films grown at 250°C. LFMSM is a way to obtain ITO films with a smooth surface, high transmittance and high electrical conductivity.