• Journal of the Optical Society of Korea
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• v.12 no.3
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• pp.166-169
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• 2008

The submersion monitoring system based on a reflective side-polished optical fiber submersion sensor with an optical fiber mirror was shown to be an effective alarm system with remote monitoringwhen the drainage capacity of a common utility duct is exceeded due to heavy rainfall. The proposed sensor was connected to an existing installed optical fiber network at a height of 250mm in a common utility duct, and then tested under sample materials(distilled water, river water, sea water, foul water, muddy water, petroleum, edible oil) at a distance of 1km from the sensor for remote sensing. In experiments, the proposed real-time sensor system reduced maintenance cost and improved monitoring efficiency by using a reflection-type side-polished optical fiber submersion sensor efficient for remote monitoring of a common utility duct.

• Korean Journal of Optics and Photonics
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• v.4 no.2
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• pp.140-144
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• 1993

A computer program for computing the edge response function(ERF) from the optical transfer function( 0TF) was developed. The ERFs of un-aberrated optical system and aberrated optical system were studied by the use of that program. We calculated the ERFs of the optical systems with a single aberration and with a combined aberration. In sagittal case, the ERE of the optical system with defocus or spherical aberration was worse than that with coma. In tagential case, the ERF of the optical system with coma was worse than that with defocusing or spherical aberraion. Both the shape and the position of ERF were varied with coma, but only the position of ERF was varied with distortion, in tangential case.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.5 s.170
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• pp.80-86
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• 2005

Optical performance evaluation results and an interference fringe pattern analysis of alignment errors for an optical head of a near-field receding (NFR) system are presented. The focusing unit is an optical head of a NFR system and is composed of a solid immersion lens (SIL) and an objective lens (OL). Generally, the size of the focusing unit is smaller than that of the conventional optical recording head. Hence there are difficulties to assemble the small focusing unit precisely. We composed an evaluation system with an interferometer and evaluated some focusing unit samples aligned and assembled by manual and present the obtained results. Using the conventional optical tool, Code V, a tolerance analysis of the alignment error between the SIL and the objective lens and an interference pattern analysis for the assembly error are executed. Then, through an analysis of the simulation results, the conceptual auto-alignment methodology using a neural network approach is considered.

• Smart Structures and Systems
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• v.12 no.1
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• pp.23-39
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• 2013

In this article, a smart multifunctional optical system-on-a-chip (SOC) sensor platform is presented and its application for fiber Bragg grating (FBG) sensor interrogation in optical sensor networks is investigated. The smart SOC sensor platform consists of a superluminescent diode as a broadband source, a tunable microelectromechanical system (MEMS) based Fabry-P$\acute{e}$rot filter, photodetectors, and an integrated microcontroller for data acquisition, processing, and communication. Integrated with a wireless sensor network (WSN) module in a compact package, a smart optical sensor node is developed. The smart multifunctional sensor platform has the capability of interrogating different types of optical fiber sensors, including Fabry-P$\acute{e}$rot sensors and Bragg grating sensors. As a case study, the smart optical sensor platform is demonstrated to interrogate multiplexed FBG strain sensors. A time domain signal processing method is used to obtain the Bragg wavelength shift of two FBG strain sensors through sweeping the MEMS tunable Fabry-P$\acute{e}$rot filter. A tuning range of 46 nm and a tuning speed of 10 Hz are achieved. The smart optical sensor platform will open doors to many applications that require high performance optical WSNs.

• Journal of Sensor Science and Technology
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• v.23 no.3
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• pp.165-169
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• 2014

An existing infrared (IR) analysis system is generally composed of infrared source, IR focusing lenses, IR detector, and optical chopper. An optical chopper is widely used in combination with lock-in amplifier to improve the signal-to-noise ratio by periodically interrupting incident light beam. During recent years, a few researches on miniaturized optical chopper have been reported to apply to micro-scaled optical systems. In this paper, a micro optical chopper operated by electromagnetic actuation is proposed and applied to a miniaturized micro-scaled optical system operating in IR spectral range. Additionally, the fabrication method of the proposed micro chopper is demonstrated. The proposed micro optical chopper is composed of the polydimethylsiloxane (PDMS) membrane, solenoid, and permanent magnet. The permanent magnet is bonded on the PDMS membrane using an ultraviolet-activated adhesive. The operation of the chopper is based on the attractive and repulsive forces between permanent magnet and solenoid induced by an electrical current flowing through the solenoid. The fabricated micro optical chopper could operate up to 200 Hz of frequency. The maximum operating distance of the chopper with 7mm diameter membrane was $750{\mu}m$ at 100 Hz of frequency.

• Journal of the Semiconductor & Display Technology
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• v.18 no.2
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• pp.58-62
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• 2019

Diffractive Optical Elements(DOEs) diffracts incident light using the diffraction phenomenon of light to generate a desired diffraction image. In recent years, the use of diffraction optics, which can replace existing refractive optical elements with flat plates, has been increased by implementing various optical functions that could not be implemented in refractive optical devices and by becoming miniaturized and compacted optical elements. Direct laser lithography is typically used to effectively fabrication such a diffractive optical element in a large area with a low process cost. In this study, the process conditions for fabricating patterns of diffractive optical elements in various shapes were found using direct laser lithographic system, and optical performance evaluation was performed through fabrication.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.483-486
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• 2004

A CCD-based color uniformity measurement system was set up. Through measuring the two-dimensional brightness distributions of three primary colors on the screen, chromaticity coordinate distributions of combination gray can be obtained within a few seconds. This system can be widely used in the production of LCD projection.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.440-441
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• 2004

A volumetric three-dimensional (3D) display system was presented, which utilizes a rotating two-dimensional (2D) display panel of light emitting diodes (LEDs) to generate more than 10 million volume pixels (voxels) within a cylindrical volume of 165 mm in height and 292 mm in diameter. Due to persistence of vision, momentarily addressed voxel information is perceived and fused into a 3D image. Important cues for depth perception, such as binocular parallax, accommodation, convergence and motion parallax are satisfied automatically and naturally, thus it is suitable for individual or group viewing, without the need for any special visual aids.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1051-1052
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• 2010

• The Optical Journal
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• v.10 no.3 s.55
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• pp.36-40
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• 1998