• Journal of the Optical Society of Korea
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• v.16 no.4
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• pp.336-342
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• 2012

A low-cost optimal double-prism method is proposed by using the developed MATLAB program to correct chromatic aberration. We present an efficient approach to choose a couple of low-cost glasses to obtain a low aberration double prism. The doublet prisms were made of two lead-free glasses. The relative partial dispersion of the two lead-free glasses is identical and their Abbe numbers are different greatly. The proposed design aims to minimize chromatic aberration, such as in apochromats, for paraxial ray tracing. Finally, an optimization design for real ray tracing can be evaluated by the chromatic aberration curve with a minimal area.

• Korean Journal of Optics and Photonics
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• v.30 no.1
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• pp.8-14
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• 2019

This paper presents methods to correct and evaluate the chromatic aberration occurring on the cut-off line of a headlamp without additional optical components and alignment process. To correct the chromatic aberration using a geometrical concept, the maximum differences in exit-ray angle between wavelengths are reduced by tilting the convex surface of an aspheric projection lens. To evaluate the chromatic aberration, the position and luminous intensity to be measured are suggested, and the criterion for chromatic aberration is presented through color coordinates. From the evaluation of an automotive headlamp designed using this geometrical method, it is found that the chromatic aberration of the cut-off line is significantly reduced.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.9
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• pp.119-126
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• 2013

In this paper, we propose a chromatic aberration removal algorithm in image capture devices, which considers local properties of the image. Chromatic aberration is generated by the fact that the refractive index of the lens is different for different wavelengths, which produces color artifacts on strong edge due to misalignment of RGB channels. Under the characteristics of the artifacts, the proposed algorithm first estimates the regions with the apparent color artifacts as the neighborhoods of the strong edge. In the regions, the proposed algorithm removes the color artifacts by matching the edges of RGB channels. The widely used conventional methods based on global image warping could not remove the color artifacts of longitudinal chromatic aberration and purple fringing identified by the image sensor, whereas the matching process of the proposed method could reduce them. Experimental results show that the proposed algorithm outperforms the conventional methods on objective and subjective criteria.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1761-1766
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• 2004

Recently, Plastic optical products are widely used. Injection molding process has advantages of low cost and high productivity. However, it remains a residual birefringence and residual stress by difference cooling. The present study focused on measuring birefringence in optical plastic parts using interference color pattern. The main idea of an analysis comes from chromatic aberration which is caused by difference light wavelengths. As a result, a complete system measuring the high order 2-D birefringence pattern was built. Further investigation is under way to improve the accuracy of birefringence measurement system by diode laser.

• Laser Solutions
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• v.2 no.2
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• pp.18-26
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• 1999

An innovative real-time weld monitoring technique using chromatic filtering of the thermal radiation from a weld pool is developed. The thermal radiation from the weld pool is focused on an aperture and the transmitted thermal radiation is monitored at two wavelengths with high-speed single-element detectors. Due to the chromatic aberration introduced in the focusing optics, the transmittance curve of thermal radiation varies by the wavelength. Owing to this difference in the transmittance, the local variation of thermal radiation from the weld pool can be monitored by processing the two spectroscopic signals from two detectors. In this paper, the algorithms to monitor the laser power on the weld specimen and the focus shift we investigated and the performances of laser power and focus monitoring are shown for a pulsed Nd:YAG laser welding. The monitoring of the weld pool size variation is also discussed.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.4-11
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• 2005

In this paper, we propose novel optics design for media inside near-field recording (NFR) using hemispherical solid immersion lens (HMS). To obtain strong advantage of data protection and high data capacity simultaneously, HMS based near field optics using aplanatic position of super hemisphere is designed. In this design, to improve small optical tolerance of this aplanatic position, additional aspheric lens surface is added on top of the HMS and it is combined with zoom optics which composed of two single lenses having low numerical aperture (NA). Also, to compensate chromatic aberration which happens seriously in optics using blue laser diode, diffractive optical element is used. Using zoom optics, additional aspheric lens surface, and diffractive optical element together, wavefront aberration and chromatic aberration are effectively reduced in broad range of cover layer thickness and wavelength variation. In addition, In this paper, effect of gap induced aberration is investigated by analyzing different behavior of each TM and TE wave for designed media inside dual-layer NFR optics.

• Transactions of the Society of Information Storage Systems
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• v.2 no.1
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• pp.13-20
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• 2006

In this paper, we propose novel optics design for media inside near-field recording(NFR) using hemispherical solid immersion lens(HMS). To obtain strong advantage of data protection and high data capacity simultaneously, HMS based near field optics using aplanatic position of super hemisphere is designed. In this design, to improve small optical tolerance of this aplanatic position, additional aspheric lens surface is added on top of the HMS and it is combined with zoom optics which composed of two single lenses having low numerical aperture(NA). Also, to compensate chromatic aberration which happens seriously in optics using blue laser diode, diffractive optical element is used. Using zoom optics, additional aspheric lens surface, and diffractive optical element together, wavefront aberration and chromatic aberration are effectively reduced in broad range of cover layer thickness and wavelength variation. In addition, in this paper, effect of gap induced aberration is investigated by analyzing different behavior of each TM and TE wave for designed media inside dual-layer NFR optics.

• Korean Journal of Optics and Photonics
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• v.26 no.4
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• pp.217-225
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• 2015

This paper shows the best selection and combination of glass in lens design, to correct a chromatic aberration using achromatic and apochromatic conditions. Using this research result, we have designed a telecentric lens for machine vision in the full range of visible light. We obtain good optical quality in the form of a quite small RMS wavefront error of $0.057{\lambda}$ in the super-broadband wavelength range 380 nm -780 nm. This result is better than that for a common telecentric lens in the visible wavelength range 486.1-656.2 nm.

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.100-101
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• 2002

This paper show lens design and simulation for microdisplay system with two mirror, Lens design optimized consider to spherical aberration, astigmatism, distortion, and chromatic aberration.

• Current Optics and Photonics
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• v.4 no.1
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• pp.23-30
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• 2020

This paper presents a new method for designing a lens system stable against chromatic variation at a specified wavelength. Conventional lenses are corrected for chromatic aberration, but the new method suppresses chromatic changes of the marginal ray in the image-side. By doing so, paraxial properties of the lens system are stabilized against chromatic variation. Since the new method is based on paraxial ray tracing, the stabilizing conditions against chromatic variation are given by recurrence formulas. However, there is an analytic solution for the case of a cemented doublet in the air. A stable doublet at 405 nm wavelength is designed and analyzed.