• Korean Journal of Optics and Photonics
• /
• v.7 no.4
• /
• pp.314-321
• /
• 1996

In this paper, the chemical process of each step in fabricating the holographic phase diffraction grating with silver salt sensitive materials has been studied in detail. A new analysis of the bleaching methods have been made through the study. The result shows that among the types of bleaching methods, the reversal bleach can not be reacted chemically. And the experiments about the chemical reactions, the characteristics of the reaction products and the refractive modulation types by the bleaching methods have been done to prove the theory. It is investigated that the exposure acts as the catalyst of developing reaction and affects the developing reaction time conspicuously. At the optimum developing reaction times, which could be taken from the experiments, the holographic diffraction gratings with high diffraction efficiency over 70% could be obtained in the range of the exposure quantity 50~350 [$\mu$J/ $\textrm{cm}^2$]. From the experiments about the correlation of the chemical processing conditions of the composition of developers, the exposure, and the developing reaction time, it has proved that the enhancement of the diffraction efficiency is impossible in the limited exposure energy and conventional constant chemical reaction time.

• Journal of the Korean Graphic Arts Communication Society
• /
• v.4 no.1
• /
• pp.43-55
• /
• 1986

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.05a
• /
• pp.155-156
• /
• 2010

• Korean Journal of Optics and Photonics
• /
• v.33 no.6
• /
• pp.324-330
• /
• 2022

We measured the Dill and Mack model parameters that determine the exposure and development characteristics of photoresists, respectively. First, photoresist samples were prepared while altering the exposure dose, and changes in transmittance were measured. Analyzing these results, the Dill model parameters A, B, and C were determined. In particular, the exact solution of the Dill model equation was used to determine the C parameter. In addition, changes in thickness were measured as a function of development time for different exposure doses, and the Mack model parameters R_min, R_max, a, and n were determined using the results. We also determined parameter values for the reduced Mack model that uses only three parameters, R_min, R_max, and n. The root mean square error between the model predictions and the measured values for the photoresist thickness was found to increase slightly compared to the case using the original Mack model with four parameters.

• Korean Journal of Optics and Photonics
• /
• v.9 no.5
• /
• pp.315-320
• /
• 1998

The characteristics and structures of photopolymer are analyzed in this paper, which recently have various applications in optical information processing and optical memory, Especially, Du Pont's photopolymer OmniDex 706 reflection film is used in many experiments of different exposures and incident angles, and analyzed by the diffraction pattern generated by glass plate's reflection beam. With the dark reaction of the monomer in photopolymerization, dynamic parameters are considered due to the variation of exposure time and diffusion time delay after exposure. The performance of diffraction efficiency is improved by 10%, when an exposure time is 6.25 sec, and a diffusion time delay is 2 minute.

• Journal of the Korean Vacuum Society
• /
• v.12 no.4
• /
• pp.288-292
• /
• 2003

The fabrication of silicon nano-master with pillar structures using E-beam lithography and ICP etching was investigated for application of 2-dimensional polymer photonic crystal waveguides with air hole structures. Pillar structures with square, hexagon, dodecagon and circle were successfully fabricated. The diameters and structures of fabricated pillars were measured by CD-SEM and SPM-AFM. It was found that the optimal dose for complete circle pillar structures was 432 $\mu$C/$\textrm{cm}^2$.

• Journal of Bio-Environment Control
• /
• v.29 no.4
• /
• pp.399-405
• /
• 2020

Recently, it is difficult to produce uniform scions and rootstocks with high quality in a greenhouse due to weather extremes. The closed transplant production system is useful for producing scions and rootstocks with desirable morphological characteristics by environment control regardless of weather outside. In this study, we investigated transpiration rates and growth of cucumber and tomato scions and rootstocks grown under different light intensity conditions for precise irrigation control in a closed transplant production system. Hanging system to measure continuously the weight of plug tray consisting of seedlings and substrate with load-cell was installed in each growing bed. Using this system, we confirmed initial wilting point of cucumber and tomato seedlings, and conducted subirrigation when moisture content of substrate was not below 50%. The irrigation time of cucumber scions and rootstocks were 7 and 6 days after sowing, respectively. In tomato scions and rootstocks grown under PPF (photosynthetic photon flux) 300 μmol·m^-2·s^-1, the irrigation time were 5, 8, 11, and 13 days after sowing. Increasing light intensity increased transpiration rates and differences of transpiration rates by light intensity was higher in tomato seedlings. The growth of cucumber and tomato seedlings was promoted by increasing light intensity, especially, hypocotyl elongation and stem thickening was affected by light intensity. Cumulative transpiration rate of plug tray in cucumber and tomato seedlings was increased by increasing light intensity, and daily transpiration rate per seedling was regressed by 1st-order linear equation with high correlation coefficient. Estimation of transpiration rates by weighing continuously plug tray of vegetable seedlings can be useful to control more accurately irrigation schedule in a closed transplant production system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.05c
• /
• pp.240-244
• /
• 2003

후막 리소그라피 기술은 기판 위에 감광성 페이스트를 도포한 후 자외선과 패턴마스크를 사용하는 광식각(photolithography) 방법을 이용하여 세부 패턴을 형성시키는 기술이다, 이 기술은 후막기술로서는 높은 해상도인 선폭 $30{\mu}m$ 이하의 미세도선을 구현할 수 있어, 후막기술을 이용한 고주파 모듈의 제조에 있어서 새로운 대안으로 주목받고 있다. 본 연구에서는 알루미나 기판 상에 수십 ${\mu}m$ 이하의 마이크로 비아를 가지는 유전체 층을 형성시킬 수 있는 저온소결용 감광성 유전체 페이스트를 개발하였다. 저온소결용 유전체 파우더와 폴리머, 모노머, 광개시제 등의 양을 조절하여 마이크로 비아를 형성할 수 있는 최적 페이스트 조성을 연구하였으며, 노광량 및 현상시간과 같은 공정변수가 마이크로 비아의 해상도에 미치는 영향을 평가하였다. 알루미나 기판에 전면 프린팅 한 후 건조, 노광, 현상, 소성 과정을 거쳐 소결전 $37{\mu}m$, 소결후 $49{\mu}m$의 해상도를 가지는 마이크로 비아를 형성할 수 있었다.

• Korean Journal of Optics and Photonics
• /
• v.11 no.4
• /
• pp.255-260
• /
• 2000

We report that the crack-free organic-inorganic hybrid silica thin films were fabricated by sol-gel process using organometallic compounds as a precursor and that we have established very reproducible fabrication condition with systematic investigation of thickness and refractive index variations for various control parameters, such as, coating type, coating speed, chemical composition, prebake and postbake temperature. Additionally, we measured and compared the change of optical property with the UV exposure dose for three different kinds of photoinitiators. Furthermore, the fabrication of Ix4 MMI optical power splitter using the sol-gel thin film provides the possibility of various applications to the optical waveguide devices. vices.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.22 no.4
• /
• pp.39-43
• /
• 1985

The charcterization of optical lithography on the step and repeat projection system is studied. Parameters that influence optical lithography were analyzed and the experiment was performed on the mask of $\pm$ 5rm, the surface flatness. From the experiment, the relationship between linewidth diviation on defocus and linewidth shift on exposure of the small features is obtained. Conditions maintaining good uniformity of small features from these relation-ships is presented.