• Journal of the Microelectronics and Packaging Society
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• v.25 no.2
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• pp.35-39
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• 2018

In order to improve the coupling efficiency, a collimator lens that collects the light emitted from the laser diode at a wide angle to the core of the optical fiber is essential. Glass mold method using a mold is widely used as a collimator lens currently used. Although this method is inexpensive to produce, it is difficult to form precisely and quality problems such as spherical aberration. In this study, the precision of surface processing was improved by replacing the existing glass mold method with the semiconductor process, and the material of the lens was changed to silicon suitable for the semiconductor process. The semiconductor process consists of a photolithography process using PR and a dry etching process using plasma. The optical coupling efficiency was measured using an ultra-precision alignment system for the evaluation of the optical characteristics of the silicon lens. As a result, the optical coupling efficiency was 50% when the lens diameter was $220{\mu}m$, and the optical coupling property was 5% or less with respect to the maximum optical coupling efficiency in the lens diameter range of $210-240{\mu}m$.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.6
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• pp.143-150
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• 2004

In this paper, resonant ultrasound spectroscopy(RUS) was used to determine the natural frequency of a ceramic ferrule and a ball lens. The ceramic ferrules are cylinderical shape with $\phi$ 2.56mm diameter and l0mm in length. Crack lengths of these ferrules are 10.40$\mu$m, 21.18$\mu$m and 32.35$\mu$m. The spherical ball lens was made of BK-7 glass, one's diameter in 2mm and 5mm. RUS system is consisted of spectrum analyzer, power amplifier, PZT sensor and support frame. The principle of RUS is that the mechanical resonant frequency of the materials depends on density and the coefficient of elasticity. Rus system is based on that given resonant frequency of the materials can be represented by the function of density and the coefficient of elasticity, and it is applied to excite specimen and to inspect the difference of natural frequency pattern between acceptable specimen and defective ones. Defect evaluation by RUS are performed to investigate the natural frequency measure of ferrule and ball lens.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.7
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• pp.46-52
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• 2004

The Magnetorheological fluid has the properties that its viscosity has drastic changed under some magnetic fields therefore, Magnetorheological fluids has been used fur micro polishing of the micro part(for example, a spherical surface in a micro lens). The polishing process may appears as follows. A part rotating on the spindle is brought into contact with an Magnetorheological finishing(MRF) fluids which is set in motion by the moving wall. In the region where the part and the MRF fluid are brought into contact, the applied magnetic field creates the conditions necessary for the material removal from the part surface. The material removal takes place in a certain region contacting the surface of the part which can be called the polishing spot or zone. The polishing mechanism of the material removal in the contact zone is considered as a process governed by the particularities of the Bingham flow in the contact zone. Resonable calculated and experimental magnitudes of the material removal rate for glass polishing lends support the validity of the approach.