• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.31-35
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• 2001

The anti-reflective anti-static(ARAS) optical film Was designed using conducting layer $TiN_x$ by Essential Macleod program. From this results, [air ${TiN_x{\mid}SiO_2{\mid}$ glass] two layer shows wide-band AR coating in the wavelength range of 450~700 nm. The $TiN_x$ thin films were prepared on the glass substrate by RF(radio-freqency) magnetron sputtering apparatus from a Ti target in agaseous mixture of argon and nitrogen with the thickness of 7~10 nm. For the films obtained, the chemical binding energy of the films was investigated by x-ray photoelectron spectroscopy(XPS) in order to analyze the chemical nature and composition of the films. In addition, we investigated the relationship between the surface resistance and the chemical nature the sheet resistance and XPS depth profiling the chemical binding of the films.

• Macromolecular Research
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• v.10 no.1
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• pp.2-12
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• 2002

The small-angle X-ray scattering (SAXS) beamline BL4C1 at the 2.5 GeV storage ring of the Pohang Accelerator Laboratory (PAL) has been in its first you of operation since August 2000. During this first stage it could meet the basic requirements of the rapidly growing domestic SAXS user community, which has been carrying out measurements mainly on various polymer systems. The X-ray source is a bending magnet which produces white radiation with a critical energy of 5.5 keV. A synthetic double multilayer monochromator selects quasi-monochromatic radiation with a bandwidth of ca. 1.5%. This relatively low degree of monochromatization is sufficient for most SAXS measurements and allows a considerably higher flux at the sample as compared to monochromators using single crystals. Higher harmonics from the monochromator are rejected by reflection from a flat mirror, and a slit system is installed for collimation. A charge-coupled device (CCD) system, two one-dimensional photodiode arrays (PDA) and imaging plates (IP) are available its detectors. The overall performance of the beamline optics and of the detector systems has been checked using various standard samples. While the CCD and PDA detectors are well-suited for diffraction measurements, they give unsatisfactory data from weakly scattering samples, due to their high intrinsic noise. By using the IP system smooth scattering curves could be obtained in a wide dynamic range. In the second stage, stating from August 2001, the beamline will be upgraded with additional slits, focusing optics and gas-filled proportional detectors.

• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.217-222
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• 1998

Coating films of $SiO_2-TiO_2-AgO$ have been prepared on soda-lime-silica slide glasses and single crystal silicon wafer by the sol-gel method using a spin-coating technique. Commercially available tetraethyl orthosilicate, titanium trichloride, and silver-nitrates were used as starting materials. The heat treatment temperature of this coating films was $500^{\circ}C$ properly, obtained from TG-DTA result. The films with thickness of 310 nm were prepared by 5 times coating. In the case of l0 mol% AgO, the film showed a crack-free and smooth surface, but the higher Ago content exhibited the more pin hole and the segregated cluster of AgO. The IR absorbance of the films decreased in the range of 400 nm to 700 nm with the increase of annealing temperature. And the reflectance of the coating films decreased and the color was changed light yellow to white yellow with the increase of Ago content.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.3
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• pp.120-123
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• 2005

The 5 mol% ZnO doped $LiNbO_3$ film and the 2 mol% MgO doped $LiNbO_3$ film were grown on the $LiNbO_3$ (001) substrate by liquid phase epitaxy (LPE) method with $Li_2CO_3-V_2O_5$ flux system. The crytsallinity and the lattice mismatch between $Zn:LiNbO_3$, film and $Mg:LiNbO_3$, film were analyzed by x-ray rocking curve (XRC). In addition, the ZnO and MgO distribution in the cross-section of the multilayer thin films was observed using electron probe micro analyzer (EPMA).

• Korean Journal of Optics and Photonics
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• v.19 no.3
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• pp.193-198
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• 2008

A novel refractive index sensor, which consists of polymer channel waveguide overlaid with $TiO_2$ thin film, is demonstrated. To evaluate the fabricated sensor, we measured the polarimetric interference induced by concentration change of injected glycerol solution. Our experimental results show that thicker $TiO_2$ film improves the sensitivity of the polarimetric interferometer. For the fabricated waveguide with a 20 nm thick $TiO_2$ film, the measured index change to lead phase variation of $2{\pi}$ is $1.8{\times}10^{-3}$.

• Korean Journal of Optics and Photonics
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• v.8 no.5
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• pp.387-394
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• 1997

The influences of laser-induced damage threshold by the after-processing of $Al_2O_3$ thin films was investigated. The samples were fabricated at the substrate temperature of $100^{\circ}C$, $200^{\circ}C$, $300^{\circ}C$ and $350^{\circ}C$ respectively, and the LIDT were measured by using Nd:YAG laser. After the processing with baking and laser conditioning of the samples, the variation of LIDT was measured. It was found that LIDT was enhanced twice by laser-conditioning process and 1.5 times by baking process. In addition, we measured the chemical properties of the thin film structure before and after the processing by using XPS.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.7.1-7.1
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• 2011

Nanoporous templates have been widely used for the development of new functional nanostructured materials suitable for electronics, optics, magnetism, and energy storage materials. We have prepared nanoporous templates by using thin films of mixtures of polystyrene-block-poly (methyl methacrylate) (PS-b-PMMA) and PMMA homopolymers. These templates have cylindrical nanoholes spanning the entire thickness of the film. Some applications of nanoporous templates are introduced: a) anti-reflective coating, b) the preparation of conducting polymer nanowires of poly (pyrrole), poly (3,4-ethylenedioxy-thiopene) onto a glass coated with indium-tin-oxide, and c) the separation membranes for biomaterials. We found that when the pore fraction of nanoholes in the film was ~0.68, almost zero reflectance at a specific wavelength, which can be changed with film thickness, was achieved at visible wavelengths Furthermore, ultra high density array of conducting nanowires was successfully prepared onto various substrates including flexible polymer. Due to highly alignment of polymer chain along the nanowire direction, the conductivity was much increased. Furthermore, these nanoporous films were found to be very effective for the separation of human Rhinovirus type 14 (HRV 14), major pathogen of a common cold in humans, from the buffer solution. We also found that when the pore size was effectively controlled down to 6 nm, a single file diffusion was observed.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.729-735
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• 2021

Recently Artificial Intelligence(AI) has been developed and used in various fields. Especially AI recognition technology can perceive and distinguish images so it should plays a significant role in quality inspection process. For stability of autonomous driving technology, semiconductors inside automobiles must be protected from external electromagnetic wave(EM wave). As a shield film, a thin polymeric material with hole shaped micro-patterns created by a laser processing could be used for the protection. The shielding efficiency of the film can be increased by the hole structure with appropriate pitch and size. However, since the sensitivity of micro-machining for some parameters, the shape of every single hole can not be same, even it is possible to make defective patterns during process. And it is absolutely time consuming way to inspect all patterns by just using optical microscope. In this paper, we introduce a AI inspection system which is based on web site AI tool. And we evaluate the usefulness of AI model by calculate Area Under ROC curve(Receiver Operating Characteristics). The AI system can classify the micro-patterns into normal or abnormal ones displaying the text of the result on real-time images and save them as image files respectively. Furthermore, pressing the running button, the Hardware of robot arm with two Arduino motors move the film on the optical microscopy stage in order for raster scanning. So this AI system can inspect the entire micro-patterns of a film automatically. If our system could collect much more identified data, it is believed that this system should be a more precise and accurate process for the efficiency of the AI inspection. Also this one could be applied to image-based inspection process of other products.

• Korean Journal of Optics and Photonics
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• v.21 no.4
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• pp.175-178
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• 2010

A transmission type color filter based on a thin film Ag-$SiO_2$-Ag etalon was proposed and realized in a quartz substrate. The device could acquire infrared suppressed transmission and wide effective area compared to costly e-beam lithography and laser interference lithography. The FDTD method was introduced to take into account the effect of the dispersion characteristics of the silver metal and the thickness thereof. Three different color filters were devised: The cavity length for the red, green and blue filters were 160 nm, 130 nm, and 100 nm respectively, with the metal layer unchanged at 25 nm. The observed center wavelengths were measured at 650 nm, 555 nm, and 480 nm for the red, green, and blue devices; the corresponding bandwidths were about 120 nm, 100 nm, and 120 nm; and the peak transmission for all was ~60%. Finally the relative transmission was measured to decline with the angle of the incident beam with the rate of 1%/degree.

• Korean Journal of Optics and Photonics
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• v.7 no.2
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• pp.129-135
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• 1996

We observed the absorptive optical bistability in the single layer amorphous $As_2S_3$ thin film which has an isolated electron pairs at roomtemperature, for the frist time, $Ar^+$ laser beam (λ=514.5 nm) was used as a light source and was focused by thin lens. The experiment was performed in cavityless system and the occurrence of optical bistability in this material could be explained by the temperature-dependent absorption coefficient of the sample. Also, this effect was explained by the reversible shift of the absorption edge in this material. The condition of optical bistability is determined by detuning value ($a_0L$) and this value was 0.12 when thikness of that sample was about 0.8 ${\mu}{\textrm}{m}$. The switching was observed clealy when light intensity is 150~180 mW and the swiching time was about $10^{-4}$ s.