• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.444-447
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• 2005

This paper is described about the technique of ultra-precision machining for a infrared camera aspheric mirror. A 200 mm diameter aspheric mirror was fabricated by SPDTM. Aluminum alloy as mirror substrates is known to be easily machined, but not polishable due to its ductility. Aspheric large reflector without a polishing process, the surface roughness of 5 nm Ra, and the form error of $\lambda/2\;(\lambda=632.8 nm)$ for reference curved surface 200 mm has been required. The purpose of this research is to find the optimum machining conditions for cutting reflector using A16061-T651 and apply the SPDTM technique to the manufacturing of ultra precision optical components of Al-alloy aspheric reflector.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.1
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• pp.43-48
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• 2005

This paper is described about the technique of ultra-precision machining for an aerospace aspheric mirror. The reflection mirror system generates parallel beams inside a thermal vacuum chamber. A 200mm diameter aspheric mirror was fabricated by SPDTM. Aluminum alloy as mirror substrates is known to be easily machined, but not polishable due to its ductility. Aspheric large reflector without a polishing process, the surface roughness of 10nm Ra, and the form error of ${\lambda}/2$ (${\lambda}$=632.8nm) for reference curved surface 200mm has been required. The purpose of this research is to find the optimum machining conditions for cutting reflector using Al6061-T651 and apply the SPDTM technique to the manufacturing of ultra precision optical components of Al-alloy aspheric reflector.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.5 s.182
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• pp.44-50
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• 2006

This paper describs about the technique of ultra-precision machining for an infrared(IR) camera aspheric mirror. A 200 mm diameter aspheric mirror was fabricated by SPDTM(Single Point Diamond Turning Machine). Aluminum alloy as mirror substrates is known to be easily machined, but not polishable due to its ductility. Aspheric large reflector without a polishing process, the surface roughness of 5 nm Ra, and the form error of ${\lambda}/2\;({\lambda}=632.8\;nm)$ for reference curved surface 200 mm has been required. The purpose of this research is to find the optimum machining conditions for cutting reflector using Al6061-T651 and apply the SPDTM technique to the manufacturing of ultra precision optical components of Al-alloy aspheric reflector. The cutting force and the surface roughness are measured according to each cutting conditions feed rate, depth of cut and cutting speed, using diamond turning machine to perform cutting processing. As a result, the surface roughness is good when feed rate is 1mm/min, depth of cut $4{\mu}m$ and cutting speed is 220 m/min. We could machined the primary mirror for IR camera in diamond machine with a surface roughness within $0.483{\mu}m$ Rt on aspheric.

• Korean Journal of Optics and Photonics
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• v.24 no.3
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• pp.111-119
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• 2013

A large aspheric mirror is a key component for large astronomical telescopes and high resolution satellite cameras. Since it is large and has an aspheric form, it is much more difficult to fabricate it compared to the similar size of spherical mirror. Especially, the opto-mechanical design and analysis is critical to reduce the deformation of mirror surface due to the external forces such as gravity or temperature change, as the mirror size is larger and lightweighting ratio is increased. The design requirements for the mirror are different depending on the particular ground and space applications because the environmental conditions are changed. In this paper, we explain the opto-mechanical design and analysis for ground and space applications that are among the most difficult to achieve among several technologies related to development of the large aspheric mirror.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.897-900
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• 2002

The collimation mirror will be used for thermal vacuum testing of spacecraft. The reflection mirror system to generate parallel beam inside the thermal vacuum chamber. A 600mm diameter aspheric Collimation mirror was fabricated by ultra-precision single point diamond turning (SPDT). Aluminum alloy for mirror substrates is known to be easily machining, but not polishable due to its ductility. Aspheric large collimation reflector without a conventional polishing process, the surface roughness of 10nmRa, and the from error of $\lambda/2 ~\lambda/4(\lambda$ =632.8 nm) for reference curved surface 600 mm has been required. The purpose of this research is to find the optimum machining conditions for reflector cutting of A16061-T651 and apply the SPDT technique to the manufacturing of ultra precision optical components of metal aspheric reflector.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.4
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• pp.1-5
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• 2002

A 110 m diameter aspheric metal secondary mirror for a test model of an earth observation satellite camera was fsbricated by ultra-precision single point diamond turning (SPDT). Aluminum alloy for mirror substrates is known to be easily machinable, but not polishable due to its ductility. A harder material, Ni, is usually electrolessly coated on an A1 substrate to increase the surface hardness for optical polishing. Aspheric metal secondary mirror without a conventional polishing process, the surface roughness of Ra=10nm, and the form error of Ra=λ/12(λ=632.8nm) has been required. The purpose of this research is to find the optimum machining conditions for reflector cutting of electroless-Ni coated A1 alloy and apply the SPDT technique to the manufacturing of ultra precision optical components of metal aspheric reflector.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.1125-1128
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• 2001

A 110mm diameter aspheric metal secondary mirror for a test model of an earth observation satellite camera was fabricated by ultra-precision single point diamond turning(SPDT). Aluminum alloy for mirror substrates is known to be easily machinable, but not polishable due to its ductility. A harder material, Ni, is usually electrolessly coated on an Al substrate to increase the surface hardness for optical polishing. Aspheric metal secondary mirror without a conventional polishing process, the surface roughness of Ra=10nm, and the form error of Ra=λ/12(λ=632nm) has been required. The purpose of this research is to find the optimum machining conditions for reflector cutting of electroless-Ni coated Al alloy and apply the SPDT technique to the manufacturing of ultra precision optical components of metal aspheric reflector.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.83-87
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• 2001

A 110 mm diameter aspheric metal secondary mirror for a test model of an earth observation satellite camera was fabricated by ultra-precision single point diamond turning (SPDT). Aluminum alloy for mirror substrates is known to be easily machinable, but not polishable due to its ductility. A harder material, Ni, is usually electrolessly coated on an Al substrate to increase the surface hardness for optical polishing. Aspheric metal secondary mirror without a conventional polishing process, the surface roughness of Ra=10nm, and the form error of $Ra={\lambda}/12({\lambda}=632nm)$ has been required. The purpose of this research is to find the optimum machining conditions for reflector cutting of electroless-Ni coated Al alloy and apply the SPDT technique to the manufacturing of ultra precision optical components of metal aspheric reflector.

• Current Optics and Photonics
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• v.1 no.6
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• pp.618-625
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• 2017

In the present research, a new bending system using a segmented vacuum chuck for Stressed Mirror Polishing (SMP) is developed. SMP is a special fabrication method for thin aspheric mirrors, where simple flat or spherical fabrication is applied while a mirror blank is deflected. Since a mirror blank is usually glued to a bending fixture in the conventional SMP process, there are drawbacks such as long curing time, inconvenience of mirror replacement, risk of mirror breakage, and stress concentration near the glued area. To resolve the drawbacks, a new bending system is designed to effectively hold a mirror blank by vacuum. For the developed bending system, the optimal bending load to achieve the designated mirror deflection is found by finite element analysis and an optimization algorithm. With the measurement results of the deflected mirror surfaces with the optimal bending loads, the feasibility of the developed bending system is investigated. As a result, it is shown that the bending system is appropriate for the SMP process.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.1
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• pp.114-119
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• 2011

There is a limit to technology of improving luminous intensity uniformity and glare, known as a weakness of existing LED lamp. Because of Using many LED, LED lamp not only waste energy but have bad effect on efficiency. Our goal is to develop security lights solution which is contented with suitable area in KS(Korean Industrial Standards) and to remove glare by combining asphere in optical system with different concept. To improve luminous intensity uniformity, a reflect mirror system was used after an aspheric optical system design for this study. We made a mirror and measured it after analysing luminance changes depend on aspheric shapes with simulation program to see if aspheric shapes effect luminance distribution. We made progress to find problems and improve them by comparing measured data and analysed data. This result of the study will contribute to industry of LED lighting through developing solution of emotional illumination of LED security lights by knowing the importance of reflectivity with this study and improving luminous intensity uniformity with solving the problem.