• Journal of Sensor Science and Technology
• /
• v.5 no.3
• /
• pp.65-73
• /
• 1996

One of the important factor in drug stuffs to a patient is to inject exact amount with stable flow rates. Since improper injection amount and flow rates would cause bad effect to recovery of a patient, the detecting sensors with high sensitivity is required for an injection pump systems' performance improvement. In this study, the three sensors, piezo film sensor, photo transistor and photo array, were compared to find best one for an injection pump monitoring system. Using suggested data processing technique and photo array sensors, we could minimize the effect of interference, disturbance, illumination, and sensitivity change caused by sensor's position. According to the experiments, the photo array showed the higher reliance than any other the three types of sensors.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.885-888
• /
• 2004

We have prepared and investigated the properties of photoinitiator-free photosensitive polyimide gate insulatos for organic thin-film transistors (OTFTs). The precursor was prepared from a dianhydride, 3,3',4,4'-Benzophenone tetracarboxylic dianhydride (BTDA) and novel aromatic diamine, 7-(3,5-diaminobenzoyloxy) coumarine (DA-CM). Photo-patternability of the polyimide precursor film and surface morphology of the films before and after photo-patterning process were investigated and negative pattern with a resolution of 50 ${\mu}m$ was obtained nicely. In addition, we have fabricated OTFTs with pentacene and photosensitive polyimide as a semiconductor and a gate insulator; respectively. According to the device geometry, the ${\mu}$, current modulation ratio and subthreshold swing of the devices were around 0.2${\sim}$0.4 $cm^2$/Vs, more than $10^5$ and around 3${\sim}$5 V/dec, respectively.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2003.07a
• /
• pp.295-298
• /
• 2003

Reflective mode liquid crystal on silicon (LCoS) microdisplay is the major technology that can produce extremely high-resolution displays. A very large number of pixels can be packed onto the CMOS circuit with integrated drivers that can be projected to any size screen. Large size direct-view thin film transistor (TFT) LCDs becomes very difficult to make and to drive as the information content increases. However, the existing LC alignment technology for the LCoS cell fabrication is still the mechanical rubbing method, which is prone to have minor defects that are not visible normally but can be detrimental if projected to a large screen. In this paper, application of photo-alignment to LCoS fabrication is presented. The alignment is done by three-step exposure process. A MTN $90^{\circ}$ mode is chose as to evaluate the performance of this technique. The comparison with rubbing mode shows the performance of photo-alignment is comparable and even better in some aspect, such as sharper RVC curve and higher contrast ratio.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.7
• /
• pp.1393-1398
• /
• 2009

Conventionally, etching is first considered for microelectronics fabrication process and is specially important in process of a-Si:H thin film transistor for LCD. In this paper, we stabilize properties of device by development of wet and dry etching process. The a-Si:H TFTs of this paper is inverted staggered type. The gate electrode is lower part. The gate electrode is formed by patterning with length of 8 ${\mu}$m${\sim}$16 ${\mu}$m and width of 80${\sim}$200 ${\mu}$m after depositing with gate electrode (Cr) 1500 ${\AA}$under coming 7059 glass substrate. We have fabricated a-SiN:H, conductor, etch-stopper and photo resistor on gate electrode in sequence, respectively. The thickness of these thin films is formed with a-SiN:H (2000 ${\mu}$m), a-Si:H(2000 ${\mu}$m) and n+a-Si:H (500 ${\mu}$m), We have deposited n-a-Si:H, NPR(Negative Photo Resister) layer after forming pattern of Cr gate electrode by etch-stopper pattern. The NPR layer by inverting pattern of upper gate electrode is patterned and the n+a-Si:H layer is etched by the NPR pattern. The NPR layer is removed. After Cr layer is deposited and patterned, the source-drain electrode is formed. In the fabricated TFT, the most frequent problems are over and under etching in etching process. We were able to improve properties of device by strict criterion on wet, dry etching and cleaning process.

• Journal of the korean Society of Automotive Engineers
• /
• v.11 no.6
• /
• pp.48-56
• /
• 1989

A shock tube technique was developed in which a freely falling droplets column produced by an ultrasonic atomizer was ignited behind reflected shock. In the present study, the effects of turbulent mixing on the ignition delay of a cetane was decided, also, ignition process was investigated. For the purpose of disturbance of droplets column and mixing, authors installed turbulent lattice in shock tube. Usually, the ignition delay is so called Arrhenius plot which found break point in the Arrhenius plot on the high temperature side. The rate of misfiring increased rapidly below 1080K, but ignition took place from 838k and luminous flame was seen to spread over the whole section by turbulent lattice. Length, from end plate to turbulent lattice, was varied with 60,40,20mm. Also, ignition process was detected by Photo transistor. As a result, it was found that physical factors changed ignition delay greatly and turbulent mixing had a considerable effects in the ignition process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.22 no.12
• /
• pp.1058-1062
• /
• 2009

For the investigation of the mechanism of photoelectric characteristics of a hydrogenated amorphous silicon thin film transistor(a-Si:H TFT), spectral characteristics of various backlights were analyzed in terms of the photon energy at each wavelength. Photon energy spectral characteristics were obtained through the multiplication of each photon energy and spectral intensities of backlights at each wavelength and the total photon energies were obtained by the integration of the photon energy spectrums. From the comparison of the experimental photo leakage current and the calculated photon energy, it was possible to conclude that the absorption of illuminated backlight to a-Si:H layer and the generation of electrons and holes are mainly carried out at the wavelength less than 500 nm as described in previous reports.

• Transactions on Electrical and Electronic Materials
• /
• v.14 no.3
• /
• pp.156-159
• /
• 2013

The electrical properties of ZnO nanowire field effect transistors (FETs) have been investigated depending on various diameters of nanowires. The ZnO nanowires were synthesized with an Au catalyst on c-plane $Al_2O_3$ substrates using hot-walled pulsed laser deposition (HW-PLD). The nanowire FETs are fabricated by conventional photo-lithography. The diameter of ZnO nanowires is simply controlled by changing the thickness of the Au catalyst metal, which is confirmed by FE-SEM. It has been clearly observed that the ZnO nanowires showed different diameters simply depending on the thickness of the Au catalyst. As the diameter of ZnO nanowires increased, the threshold voltage of ZnO nanowires shifted to the negative direction systematically. The results are attributed to the difference of conductive layer in the nanowires with different diameters of nanowires, which is simply controlled by changing the catalyst thickness. The results show the possibility for the simple method of the fabrication of nanowire logic circuits using enhanced and depleted mode.

• Tribology and Lubricants
• /
• v.14 no.3
• /
• pp.81-86
• /
• 1998

The purpose of this paper is to measure the rotational speed of tappet in OHC valve train system. Tappet has eccentricity about cam center, which induces the tappet rotation and prevents from wear. In this paper, the experimental test rig which composes of one cam system is developed to measure the tappet rotation by using the laser generating system, rotary encoder, optical fiber, and photo transistor. The direction of tappet rotation is judged from the oder of optical signal. As results of experiment, average and instant rotational speed and average rotation angle per one cam revolution are presented. Measured results show that eccentricity ratio is dominant factor for the tappet rotation, and tappet is rotated at the base circle.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08b
• /
• pp.1295-1297
• /
• 2007

In this study, we report that the characteristics of OTFTs can be improved by the UV exposure of the surface of the synthesized photo-reactive gate insulator, and be optimized by controlling the exposure time. As a gate dielectric, the modified PVP was prepared by substituting hydroxyl group in PVP with cinnamoyl group. The synthesis details and the effects of the modified PVP on the device performance are discussed.

• Journal of the Speleological Society of Korea
• /
• no.81
• /
• pp.35-41
• /
• 2007

According as the industry develops recently, the import and export freight amount is increasing sharply, but physical distribution processing equipment ability had achieved conveyance, surge and setup of physical distribution by human's labor ability. But, inefficiency is indicated in operation of product line and warehouse or physical distribution storage equipment because is ceilinged the processing physical distribution amount and the efficiency in physical distribution processing by these labor ability.