• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.2
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• pp.310-314
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• 2015

To improve the optical performance of the backlight unit with light guide plate(LGP), we investigated the effects of LGP patterns on the brightness and viewing angles properties of the backlight unit. We designed several patterns of LGP and calculated their optical properties by the optical simulation. The results reveal that the highest brightness and wide viewing angle was achieved with the extended-closed-polygon diffusion pattern and upper triangle prism pattern of the LGP.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.5
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• pp.444-452
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• 2008

This paper presents an overall image processing approach of defect inspection of patterned TFT-LCD panels for the real manufacturing process. A prototype of AOI(Automatic Optical Inspection) system which is composed of air floating stage and multi line scan cameras is developed. Adjacent pattern comparison algorithm is enhanced and used for pattern elimination to extract defects in the patterned image of TFT-LCD panels. New region merging algorithm which is based on border expansion is proposed to identify defects from the pattern eliminated defect image. Experimental results show that a developed AOI system has acceptable performance and the proposed algorithm reduces environmental effects and processing time effectively for applying to the real manufacturing process.

• Korean Journal of Optics and Photonics
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• v.20 no.6
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• pp.361-365
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• 2009

We describe a simple method to obtain an optical sectioning in a conventional wide-field microscope by projecting a single spatial frequency grid pattern onto the object. Using a patterned beam, we have measured the height of BGA with a rough surface that provide the coherence noise. The configuration of the height measurement system using pattern beam is simple. The image acquired by this system is not depend on the coherence noises. This system is also applicable to the sample reference plan that has no pattern on ground. The reappearance and accuracy are outstanding and applicable to many industrial optical metrology.

• Journal of Institute of Convergence Technology
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• v.2 no.1
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• pp.43-48
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• 2012

Generally, in-plane position of moving object is measured referring to the reference pattern attached to the object. From optical camera to magnetic reluctance probe, there are many ways detecting a variation of the periodical pattern. In this paper, the various operating principles developed for in-plane positioning are reviewed and compared each other. And, a novel method measuring large rotation as well as x, y linear displacements is suggested, including a detailed description of the overall system layout. It is a modified version of the surface encoder, which is a robust digital measuring method. From the surface encoder, the rotation of an object is measured indirectly through a compensated input of optical servo and independently of linear displacements. So, the operating range can be extended simply by enlarging the reference pattern, without magnifying the decoding units.

• Journal of the Optical Society of Korea
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• v.17 no.1
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• pp.50-56
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• 2013

Optical-fiber electronic speckle pattern interferometry (ESPI) is a non-contact, non-destructive examination technique with the advantages of rapid measurement, high accuracy, and full-field measurement. The optical-fiber ESPI system used in this study was compact and portable with the advantages of easy set-up and signal acquisition. By suitably configuring the optical-fiber ESPI system, producing an image signal in a charge-coupled device camera, and periodically modulating beam phases, we obtained phase information from the speckle pattern using a four-step phase shifting algorithm. Moreover, we compared the actual defect size with that of interference fringes which appeared on a screen after calculating the pixel value according to the distance between the object and the CCD camera. Conventional methods of measuring defects are time-consuming and resource-intensive because the estimated values are relative. However, our simple method could quantitatively estimate the defect length by carrying out numerical analysis for obtaining values on the X-axis in a line profile. The results showed reliable values for average error rates and a decrease in the error rate with increasing defect length or pressure.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.533-534
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.539-540
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• 2013

• Journal of the Optical Society of Korea
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• v.14 no.4
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• pp.357-362
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• 2010

The joint transform correlator (JTC) has been the best known technique for pattern recognition and identification. This paper proposes a new technique of fringe adjustment by adopting a sinusoidal amplitude-modulated iterative filter convolved with an interference fringe pattern in the joint power spectrum (JPS) domain. The comparison of our new technique and other techniques is presented to show that the newly proposed technique can successfully improve both the correlation peaks and the peak signal-to-noise ratio (PSNR). Simulated results of enhanced interference fringes are also presented.

• Korean Journal of Optics and Photonics
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• v.12 no.3
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• pp.190-199
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• 2001

In this paper, we have researched the depth of focus (DOF) and cutoff intensity of the $0.1{\mu}m$rule dense line'||'&'||'space pattern according to the various off-axis illumination (OAl) conditions in the optical system of 0.65 NA using ArF excimer laser (193 nm). We have also studied the variation of the DOF and cutoff intensity according to the sub-resolution pattern (hammer head type) size for optical proximity correction (OPC) applied to the capacitor pattern and the various OAl conditions in the same optical system. As a result, it is revealed that the cross type quadrupole or annular illumination is preferred to the conventional X type quadrupole for printing the $0.1{\mu}m$ rule dense pattern. Also, we can investigate the optimal illumination condition and the size of ope sub-resolution pattern to keep a consistent DGF and cutoff intensity trends.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.1
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• pp.42-50
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• 2012

Light color reaction, immersion and diffusion operation through the mural art can be expressed in a variety of image types. In this paper, the digital pattern for mural art was formed by observation of the optical phenomena in natural gems and the relation between the optical sparkle in gems and minerals and pattern design was characterized. New possibility with relevance for design work based on ultramarine with a beautiful sheen and spectrum of the coloring was used for Sustainable 3D simulation modeling and represented by high-resolution Image graphic design.