• Journal of the Optical Society of Korea
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• v.14 no.2
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• pp.163-169
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• 2010

Novel wafer-level fabrication of a glass ball-lens is realized for optoelectronic applications. A Pyrex wafer is bonded to a silicon wafer and cross-cut into a square-tile pattern, followed by wet-etching of the underlying silicon. Cubes of Pyrex on the undercut silicon are then turned into ball shapes by thermal reflow, and separated from the wafer by further etching of the silicon support. Radial variation and surface roughness are measured to be less than ${\pm}3\;{\mu}m$ and ${\pm}1\;nm$, respectively, for ball diameter of about $500\;{\mu}m$. A surface defect on the ball that is due to the silicon support is shown to be healed by using a silicon-optical-bench. Optical power-relay of the ball lens showed the maximum efficiency of 65% between two single-mode fibers on the silicon-optical-bench.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.6
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• pp.8-14
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• 2006

The object transport system is used in many industry field such as the conveyor belt, which transports huge goods in container harbor, the magnetic levitation system, and the indexing system which transports precision components such as semiconductor and optical components. In conventional transport system, the magnetic field may damage semiconductor and the contact force may scratch on the optical lens. So ultrasonic wave transport system has been proposed to replace the previous transport system. In this paper, the good transport condition of optical lens is obtained according to the flexural beam shapes. The working frequency and transport speed are measured and the vibration characteristics of the flexural beams are investigated by Laser Scanning Vibrometer.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.11
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• pp.654-659
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• 2005

An improved power supply for APD(Avalanche Photo Diode) with a received optical power monitoring circuit allows the received optical power increase temporary without of the degradation of the electrical signal. For the cost reduction and simple fabrication, an improved power supply has been proposed that it was designed for driving a APD as a receiving device of a wireless optical transmission system. It was demonstrated that it was possible to improve a dynamic range by compensating the temperature coefficient of the APD up to 1.0 V/$^{\circ}C$ through the power supply. Also, for an efficient transmission at the receiver end, a simple structure of a single cylindrical micro-lens configuration was used in conjunction with the laser diode to partially compensate a laser beam ellipticity. For this purpose, an astigmatism introduced by the micro-lens is utilized for the additional compensation of the beam ellipticity at the receiver end. In this paper, it is demonstrated that an efficient beam shaping is realized by using the proposed configuration consisting of the single lens attached to the laser diode.

• Korean Journal of Optics and Photonics
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• v.24 no.3
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• pp.125-134
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• 2013

In case of the optical camera system with an infinite object distance, optical designs different from previous systems are required to speed up the auto-focus. As the number of lens groups is increased due to this, the conventional analytic method found it difficult to calculate the locus, and even the one-step advanced calculation method also had the trouble of taking a lot of time. In this paper, we suggested an analytic method for calculating the zoom loci by analyzing movement of one or two groups for situations corresponding to the given back focal length and effective focal length after taking a spline interpolation for each lens group. With this method, we would not only calculate the analytic zoom loci without iterations in every optical system without placing a limit on the group number at the zoom lens systems with the infinite object distance, but we would also show the utilities of this method through many examples.

• Korean Journal of Optics and Photonics
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• v.20 no.1
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• pp.1-5
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• 2009

Recently, much research has been done for to realizeing nano-scale photonic circuits based on photonic crystal, plasmonics and silicon photonics in order to overcome fundamental limits of electronic circuits. These limits include such as bottleneck of speed, and size that cannot be reduced. Even though several kinds of coupling schemes have been reported, coupling structures are still large when it is compared with the nano-scale optical circuit. In this paper, we proposed using a very thin Fresnel lens while shortening the focal length of the Fresnel lens as much as possible. We proposed, for the first time, to utilize metal slits that are able to use the optical coupling system between a nano-scale optical circuit and the standard single mode optical fiber for overcoming the limitation of focal length shortening of the Fresnel lens. Comparative study has been carried out with a FDTD simulation between normal and metal slit assisted Fresnel lens. From the result of simulation, we can achieve 65% coupling efficiency for the metal-slit Fresnel lens when the focal length of metal-slit Fresnel lens is just $4{\mu}m$. On the other hand, the coupling efficiency of the normal Fresnel lens is about 43%.

• Korean Journal of Optics and Photonics
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• v.26 no.5
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• pp.269-274
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• 2015

In this paper we design the optical system for an integrated two-channel TO-type optical transmitter to apply the HDMI interface using the code V simulator. The proposed integrated two-channel optical transmitter has two VCSELs attached in parallel on an 8-pin TO-CAN package, on top of which is a lens filter block ($1mm{\times}2mm{\times}4mm$) composed of hemispherical lenses and WDM filters. Considering two-channel transmitters manufactured with wavelength combinations of 1060nm/1270nm and 1330nm/1550nm, we obtain the optimum value of the diameter of the hemispherical lens as 0.6 mm for both combinations, and the distances L between the lens filter block and ball lens as 1.7 mm and 2.0 mm for the 1060nm/1270nm and 1330nm/1550nm wavelength combinations, respectively. At this time, the focal length f0 of the lens filter blocks for wavelengths of 1060, 1270, 1330, and 1550 nm are 0.351, 0.354, 0.355, and 0.359 mm, respectively, and the focal lengths F of light passing through the lens filter block and ball lens are 0.62 mm for 1060nm/1270nm and 0.60-0.66 mm for 1330nm/1550nm wavelength combinations.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.3
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• pp.89-95
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• 1993

This paper presents the development of CAD system for the design of lens of the Turn Signal Lamp that can model and simulate its optical performance. The system consists of three main modules: skin surface modeling module, inner lens modeling module and optical performance simulation module. Skin surface geometry can be modeled by the input of data file and inner lens can be modeled by the input of only four parameter using its geometric characteristics. Also light distribution pattern, the barometer of optical performance is generated by means of finite ray tracing method. The system display modeled geometry, ray tracing and generated light distribution pattern.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.9
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• pp.173-179
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• 2003

In optical storage device system, there are several research topics to increase its recording density. The main idea is reducing wave length of laser diode and magnifying the number of numerical aperture (NA). In conventional optical system NA cannot be over the unity in the air because of its diffraction limit. But it is possible to overcome its limitation of unity in near field using Solid Immersion Lens. In this work, the mathematical Solid Immersion Lens (SIL) design process was illustrated by using near field theory. Also, numerical SIL design parameters were calculated by means of CODE V. Through the work, we propose the new type of SIL for high density optical recording systems.

• Journal of the Optical Society of Korea
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• v.13 no.2
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• pp.201-205
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• 2009

We investigated the optimum adhesive thickness for athermalizing an elastomeric lens mount in our space optics application. Theoretical results were compared with finite element solutions using two different models; discrete circular pads and discrete circular pads with columns filling the insertion holes reflecting the reality. A noticeable difference between their optimal thicknesses was observed, and physical interpretation revealed the uncertainty of prevailing athermal equations. A pilot sample was made to check our results and thermo-optical stress was assessed using an interferometer after isothermal load. This study presented insight into preliminary design guidance in elastomeric lens mounting.

• Journal of the Optical Society of Korea
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• v.18 no.4
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• pp.345-349
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• 2014

A direct-lit color-matching liquid crystal display using a lenticular lens array with grouped lens elements that image linear RGB light sources on the RGB subpixels of a color filter to enhance transmittance is designed, simulated, and fabricated. The RGB LED linear light sources were fabricated using small RGB LEDs in a linear array arrangement, and the lenticular lens array consisted of eight units of the same structure with a gap of 2.19 mm. The optical transmittance of the liquid crystal panel was improved by as much as 240% due to the color matching.