• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.645-648
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• 2005

Microscopy has enabled the development of many advanced technologies, and higher level microscopic techniques are required according to the increase of research in nano-technology and bio-technology fields. Therefore, in many applications, we need to measure the dimension of micro-scale parts accurately, not just to observe their shapes. To establish the meter-traceability in microscopy, gratings have been widely used as a magnification standard. KRISS provides the certification service of magnification standards using an optical diffractometer and a metrological AFM (MAFM). They are based on different measurement principles, and so can give complementary information for each other. In this paper, we describe the configuration of each system and measurement procedures to certificate grating pitch values of magnification standards. Several measurement results are presented, and the discussion about them are also given. Using the optical diffractometer, we can calibrate a grating specimen with uncertainty of less than 50 pm. The MAFM can measure a grating specimen of down to 100 nm pitch value, and the calibrated values usually have uncertainty less than 500 pm.

• Journal of the Semiconductor & Display Technology
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• v.10 no.4
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• pp.131-138
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• 2011

We fabricated distributed feedback InGaAsP/InP laser diodes for optical fiber communication module and characterized the lasing properties in continuous wave operation. The active layer of 7-period InGaAsP(1.127 eV)/InGaAsP(0.954 eV) multi-quantum well structure was grown by the metal-organic chemical vapor deposition. The grating for waveguide was also fabricated by the implementation of the Mach-Zehender holographic method of two laser beams interference of He- Cd laser and the fabricated laser diode has the dimension of the laser length of $400{\mu}m$ and the ridge width of $1.2{\mu}m$. The laser diode shows the threshold current of 3.59 mA, the threshold voltage of 1.059 V. For the room-temperature operation with the current of 13.54 mA and the voltage of 1.12 V, the peak wavelength is about 1309.70 nm and optical power is 13.254 mW.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.28-31
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• 2016

In this study, it was investigated about optical simulation in highg brightness and high uniformity direct-type backlight design for medical application. Direct-type backlight has been used high-brightness backlight such as Medical LCD application. The key parameter in designing direct-type backlight was consists of three geometrical dimension such as the distance of two lamps, the gap of lamp and reflection plate and the number of lamps. It has many of variations in optical design and it causes the different properties in backlight system. It shows the best values of above parameters; 26mm of the distance of two lamps, 4.5mm of the gap of lamp and reflection plate and 16 lamps. And we produced the specimen as above condition, and acquired good result in backlight such as the value of the brightness is 6423 nit in center of emission area and less than 5% in brightness uniformity. It shows the effective ways of designing backlight system using optical simulation method for medical LCD application.

• Journal of IKEEE
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• v.24 no.2
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• pp.409-418
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• 2020

In this paper, an integrated optical, evanescent-wave biosensor utilizing a multimode interferometer based on a Si₃N₄ rib-optical waveguide consisting of the Si/SiO₂/Si₃N₄/SiO₂ stacked structure was described. The theoretical background of the multimode interferometer was reviewed, and the structure and design process were presented through numerical computational analysis. We analyzed how the dimension (length, width) of the multimode interferometer affected the sensor performance. It has been confirmed through computational analysis that the changes in the refractive index of an analyte greatly affect the mode pattern formation position and output optical power of a multimode interferometer, and proved that this principle could be applied to integrated-optic biosensor.

• Advances in Energy Research
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• v.5 no.3
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• pp.227-237
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• 2017

The continuous increase of emission rates of green house gases and the effects on global warming added a new dimension to the problem of substituting the petroleum and its derivatives by environment friendly and sustainable energy sources for the world. Solar and wind energy appear at the top of the list of renewable of high potential, widely available, of dominated technology and well accepted. Brazil is one of the few countries in the world that receives number hours of sunshine exceeding 3,000 hours per year with a daily average of 4.5 to 6 kWh. However, this potential is largely unexplored and poorly tapped. The number of renewable systems implanted in Brazil has grown in recent years, but still insignificant when compared, for example, with Germany and Spain among others. This paper presents the results of an optical study on small concentration solar collector with evacuated tube enveloping the absorber and internal reflective surface fixed on the bottom part of the evacuated tube. The designed collector has a 2D geometrical concentration ratio between 2.455 and 4.91. The orientation of the solar collector, the ratio of the radius of the receiver to the radius of the absorber, the incidence angle for each period of the year, the collector inclination angle, the aperture angle of the reflective surface, concentration and optical efficiency were determined. The ray traces and flux distribution on the absorber of the evacuated tube solar collector were determined by using the program Ray Optics Simulation. The optical efficiency varies during the year according to the solar declination. For the periods were the solar declination is close to zero the efficiencies are maximum, and the variation during the day is around 25.88% and 99.9%. For the periods were the solar declination is maximum the efficiencies are minimum, and the variation during the day is around 23.78% and 91.79%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.3
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• pp.185-191
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• 2017

Cadmium compounds with one dimension (1D) nanostructures have attracted attention for their excellent electrical and optical properties. In this study, vertically aligned CdTe-Si nanostructures with high density were synthesized by several simple chemical reactions. First, l D Te nanostructures were synthesized by silver assisted chemical Si wafer etching followed by a galvanic displacement reaction of the etched Si nanowires. Nanowire length was controlled from 1 to $25{\mu}m$ by adjusting etching time. The Si nanowire galvanic displacement reaction in $HTeO_2{^+}$ electrolyte created hybrid 1D Te-branched Si nanostructures. The sequential topochemical reaction resulted in $Ag_2Te-Si$ nanostructures, and the cation exchange reaction with the hybrid 1D Te-branched Si nanostructures resulted in CdTe-Si nanostructures. Wet chemical processes including metal assisted etching, galvanic displacement, topochemical and cation exchange reactions are proposed as simple routes to fabricate large scale, vertically aligned CdTe-Si hybrid nanostructures with high density.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.81-84
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• 2007

In this paper, fiber optic sound and vibration monitoring sensor which is latticed shape structure based on Sagnac interferometer is fabricated and tested in laboratory conditions. To detect external vibrations surface mounted fibers on the latticed steel wire fence with a dimension of 170cm by 180cm is used. To detect external sound frequency the tightened fiber optic itself wire netting fence with a dimension of 50cm by 50cm is used. Experiments for the detection of the excited vibration and sound signals were performed. A small vibrator induced external vibration signal and it is applied to the latticed structure in the range of 100Hz to several kHz. External sound signal applied to the fiber optic sensor net using non-directional sound speaker. The detected optical signals were compared and analyzed to the detected both accelerometer and microphone signals in the time and frequency domain. Based on the experimental results, distributed fiber optic sensor using Sagnac interferometer detected effectively external vibration and sound signal and had a good performance. This system can be expanded to the monitoring of a significant system and to the structural health monitoring system.

• Journal of the Korean Society of Costume
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• v.54 no.7
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• pp.41-54
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• 2004

This study purposed to apply function form content, the three concepts that have been discussed by many philosophers since ancient times, to fashion design. Specific research goals are : first, to define fashion design based on the three concepts : and second, to examine how each of the three concepts function-oriented, form-oriented and content-oriented design have been expressed in women's fashion in the $20^{th} century. For these purposes. the author considered Morris' semiotics, which is the theoretical background of the three concepts, reviewed previous researches in design area, and applied the findings to fashion design. According to the result of applying the threefold structure of semiotics. which is the theoretical background of the three concepts, the pragmatic dimension of fashion design comprehends all functional rules related to the use of dress such as body motion and protection, health and safety. air flow and durability, and its syntactic dimension comprehend all the formal elements of visual design such as the structure, shape, line, color and material of dress. The semantic dimension of fashion design includes the symbolic meanings of dress expressed by emotion, sentiment and images. The three dimensions exist interdependently with one another. According to the result of considering the characteristics of the three concepts in the scope of women's fashion in the $20^{th} century. function-oriented design is characterized by practicality and simplicity, and has been expressed as the fashion of functionalism in the 1920s, that of minimalism in the 1960s, and the basic style from 1970s to 1980s, 1990s and the present. Form-oriented design has pursued aestheticism, putting stress upon form, and has been expressed with organic shapes imitating patterns found in nature in the 1950s and with optical art fashion in the 1960s. Content-oriented design attaches importance to transmission of delicate meanings related to the mental world of human beings, and is represented with symbolic forms. Such a characteristic has been expressed in fashion in the early 20th century influenced by surrealism and, with various types of design breaking established forms as well as metaphors and humors that characterize design in the late 20th century.

• Korean Institute of Interior Design Journal
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• v.13 no.5
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• pp.181-189
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• 2004

This study consists of two parts, in which the traditional discourses about light and color are analysed hermeneutically, The first part deals with the optical and chromatic discourse that stands in the same context with the aesthetic, and the second with the analysis of color phenomenon that is constituitive of space. From the ancient time the basic parameters of the conceptual thinking such as the virtual, simulacrum, have sticked to the inevitable status, which mediates to represent the original that can never present by oneself. In modern times this specificity of the virtual could have been connected with the problem, how and by which means objects can be perceived and grasped in itself. Among the barometers to the problem ‘color’ or ‘color perception’ has been regarded as the distinct one, in which the relationship between the image and the identifying of this one, the relationship between the perceived image and the perceiving subject and the problem of the spatiality of color and surface can be dwelled on. Through the explication of the chromatic and aesthetic discourse it can be recognized that color, surface and space are interacted with one another. Colors on the surface are not only the dynamic interpoints between the memory and the forgetfulness, but also the virtual interfaces, in which the spatialising actions happen incessantly. At this point it can be illuminated that the space-constituitive dimension of color is correlative with the dimension of chromatic effects of spatialising. Therefore color as well as surface as the spatial happening must be apprehended as the one, which constitutes the spatialising and at the same time varies and shifts itself into another on the purpose of the other spatialising.

• Korean Journal of Optics and Photonics
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• v.18 no.1
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• pp.74-78
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• 2007

We report theoretical and experimental results for application of transmittance-controlled photomask technology to ArF lithography. The transmittance-controlled photomask technology is thought to be a promising technique fo critical dimension (CD) uniformity correction on a wafer by use of phase patterns on the backside of a photomask. We could theoretically reproduce experimental results for illumination intensity drop with respect to the variation of backside phase patterns by considering light propagation from the backside to the front side of a photomask at the ArF lithography wavelength. We applied the transmittance-controlled photomask technology to ArF lithography for a critical layer of DRAM (Dynamic Random Access Memory) having a 110-nm design rule and found that the in-field CD uniformity value was improved from 13.8 nm to 9.7 nm in $3{\sigma}$.