• Journal of the Korean Society for Nondestructive Testing
• /
• v.21 no.2
• /
• pp.189-196
• /
• 2001

Photoelasticity is one of the most widely used methods for whole field stress analysis. In photoelasticity, the difference and the directions of the principal stresses we given isochromatic and isoclinic fringe patterns. Conventionally, principal stress directions are measured manually by relating the polarizer and analyzer of a plane polariscope at the same time. This is known to be the Tardy compensation method. This measurement can be very tedious and time consuming in whole field analysis. It is not possible to separate isoclincs from photoelastic fringes by conventional photoelastic technique. In this study, photoelastic theory is represented by Jones matrices and 4-steps and 8-steps phase shifting methods are described A feasibility study using computer simulation is done to separate isoclincs and isochomatics from photoelastic fringes of a circular disk under diametrical compression. Fringe patterns of the disk are generated using stress optic law. The magnitudes of isoclincs and isochromatics obtained from 8-step phase shifting method are compared with those of theories. From computer simulation, it is verified to separate isoclincs and isochomatics from photoelastic fringes.

• Proceedings of the Optical Society of Korea Conference
• /
• 1996.09a
• /
• pp.50-50
• /
• 1996

• Proceedings of the Zoological Society Korea Conference
• /
• 1999.04a
• /
• pp.36-36
• /
• 1999

No Abstract, See Full Text

• Korean Journal of Oriental Medicine
• /
• v.1 no.1
• /
• pp.273-287
• /
• 1995

Moire topography, a simple technique for three-dimensional quantitation, was used to provide interference fringe photographs of the human back with sufficient accuracy to be used for detecting patient with asymmetry due to scoliosis, the disease of cervix and lumbar, muscle dysfunction. Contour lines are a suitable and widely accepted method of describing a three-dimensional surface. In the moire technique, contour lines of an object are produced as interference fringes while the object is illuminated by a spotlight through a special grating. The fringe pattern is produced by the interference of the grating and its shadow on the object. A photograph of a moire pattern on the human back will permit an assessment of the overall body shape and the symmetry of the back. This study uses shadow moire topography. Moire topography provides a non-invasive technique for quantifying the shape of the human body. In the use of moire topography for the Oriental Medicine Diagnosis, the strength of moire lies in the ablility to detect change due to deformity of human body.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.8 no.4
• /
• pp.130-135
• /
• 1999

The main scale of linear encoder greatly effects on the precision of displacement measurement. Especially when needing the long range measurement the length of main scale should be increased accordingly. In this paper we propose a linear encoder that uses laser interference pattern as main scale for long range measurement. The linear encoder is similar to Michelson interferometer excepting that the reference mirror is tilted so as to obtain interference fringe pattern and a grating panel is attached on a quadratic photo diodes. Four kinds of grating having phase difference of 0. $\pi$/4, $\pi$/2, 3$\pi$/4 are arranged on the panel. The experimental results show that signals of quadratic photo diode A, B, {{{{ {-}atop {A } }}}} and {{{{ {- } atop {B } }}}} are cosine wavelike and successive signals have phase difference of $\pi$/4 each other. So the proposed method can achieve improved measurement resolution.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.162-162
• /
• 2009

Optical bounce which occurs by over twist of the liquid crystal (LC) director has a problem of response time in fringe-field switching (FFS) modes. After removing the electric field, effective birefringence ($d{\Delta}n_{eff}$) at the edge of pixel electrode meets the $\lambda/2$ phase instantly, since tilt angle of LC directors at that position suddenly decreases compared to twist angle. In this paper, based on the careful analysis, origin of optical bounce has been explained.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.163-163
• /
• 2009

Viewing angle controllable liquid crystal display (LCD) associated with fringe-field switching (FFS) mode with high image quality is proposed. In the device, one pixel is composed of main and sub pixels, in which adjacent sub pixel is patterned with pixel electrodes direction orthogonal to the adjacent one. In this way, light leakage can be generated in the all viewing angle directions except the normal direction, realizing view angle controllable LCD in both horizontal and vertical directions.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.29A no.11
• /
• pp.62-69
• /
• 1992

In this paper, a measurement system of surface flatness test using 2-Bucket algorithm phase-shifting interferometry is designed and constructed. In the conventional surface flatness test system using phase shifting interferometry, it is needed more than 3 fringe datas but we propose 2-Bucket algorithm phase-shifting interferometry which only uses two fringe datas. 2-Bucket algorithm uses the relative phase differences of the neighbour pixels. If we watch the result of phase-shift error test simulation, 2-Bucket algorithm has the same calculating values that 3-Bucket, 4-Bucket and 5-Bucket algorithm have them. Experiments have been carried out on the silicon wafer. The measurement of silicon wafer's surface flatness shows that the flatness topography using 2-Bucket algorithm is similar to that of other algorithms.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1266-1269
• /
• 2004

This study focuses on the color characteristics of FFS (Fringe Field Switching). We use various methods to prove the high performance of color characteristics in the Fringe Field Switching mode. We have described a color performance of 15" XGA product by the viewing angle range using x, y parameters of CIE chromaticity diagram. And so we used the 2 dimensional analyzing to prove the color shift distribution by viewing angle.

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.11 s.188
• /
• pp.34-41
• /
• 2006

Nanoimprint lithography is an emerging technology which has an ability to make patterns under 100nm width. Recently many researches have been focused to develop multilayer patterning function in nanoimprint lithography and aligning method is attracting attention as a key technology. $Moir\'{e}$ has been used widely to measure dislocation or deformation of objects and considered one of the best solutions to detect aligning error in nanoimprint lithography. Concentric circular patterns are used to generate a $moir\'{e}$ fringe in this paper and aligning offset and direction are extracted from it. Especially this paper shows the difference of fringe equation of $moir\'{e}$ which can be obtained in nanoimprint process atmosphere from normal one.