• Current Optics and Photonics
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• v.2 no.4
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• pp.324-331
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• 2018

This paper describes a symmetric method for determining a combination of element power and optical material to design a catadioptric system with corrected color aberration and flat Petzval curvature. To graphically obtain the solutions, a glass chart containing the Abbe number, the refractive index, and the optical power, which are closely related to these aberrations, is suggested. First, we recompose an optical system as a doublet of the specific lens and an equivalent single lens, and then locate both lenses on lines that are symmetric to each other on a glass chart, through changing the lens parameters effectively. Utilizing this method, an achromatic catadioptric system with flat Petzval curvature is obtained.

• Journal of Korean Clinical Health Science
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• v.7 no.1
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• pp.1205-1214
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• 2019

Purpose: To investigate the effect of color soft contact lenses on the corneal thickness in young Korean population. Methods: The subjects consisted of 112 eyes (7 males, 49 females) with the mean age of $20.987{\pm}1.093years$ (range 20-25 years) in young Korean population during 2018. Test was compared the corneal thickness before and after wearing color soft contact lenses. The thinnest cornea thickness(TCT), central cornea thickness(CCT), pupil centre thickness(PCT), superior corneal thickness(SCT),inferior corneal thickness(ICT), medial corneal thickness(MCT), lateral corneal thickness(LCT) of the cornea was measured using the Pentacam pachymetry. The statistically analysis was perform the Shaparo-Wilk test. Results: The right eye was a statistically significant among the CCT,LCT, MCT and TCT values(p<0.001) in the compared the corneal thickness before and after wearing soft colour contact lenses. Also the left eye was a statistically significant among the LCT and MCT values(p<0.001) in the compared the corneal thickness before and after wearing soft colour contact lenses. However, there was no statistical difference (p>0.5) in the mean PCT between before and after wearing color soft contact lenses. Conclusion: These results suggested that the color soft contact lens wear can the effect the regional thickness of cornea. Therefore, the analysis of corneal topography with Pentacam can provide correct and useful diagnostic information of the morphology of the RGP contact lens fitting and diagnosis of corneal refraction surgery.

• Journal of the Optical Society of Korea
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• v.19 no.3
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• pp.303-310
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• 2015

An image-space telecentric lens for an intra-oral 3D scanner was designed and fabricated for dental application. Since a telecentric function can provide the same results regardless of image plane position, it helps to realize a more accurate image for an intra-oral scanner. The performance of the designed lens meets the required properties for HD resolution. In particular, lateral color is corrected within 1 pixel. This system achieves depth of focus of more than 3 mm. For user convenience, the developed system consists of a prism part and an imaging part. Both parts are optimized to reduce the front size and weight of the system. In order to make the parallax sights, parallax angle was determined to be 8 degrees between two optical systems.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.229-230
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• 2009

This paper proposes a new design of ultra-slim color mixing lens (CML) for backlight unit (BLU), and presents simulated performance of the design. The novel color mixing structure has a shorter mixing length (< 1cm) than the existing color mixing structure, and achieves high efficiency and uniformity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.2
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• pp.84-88
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• 2002

We designed 5 layer coating in using $SiO_2$and $ZrO_2$. We calculated reflectance with changing the thickness of 5th layer and visualized color of reflected light in using reflectance of RGB. by the result, when thickness is increase from 5 nm to 80 nm, red color of reflected light is decreased and increase from 80 nm to 150 nm, blue color of reflected light is increased. we maked use of Photoshop 5.0 to analyze colors.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2006.11a
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• pp.168-172
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• 2006

With the progress of the aging society into the aged society, the planning of senior housing is inevitably required. Among the factors of planning, color appeals to people's vision which mostly accepts information about the environment, so age-related color vision changes should be studied. The purpose of the study is to find out characteristics of color perception focused on yellow and blue with advancing of the yellowed eye sight in the old age. The findings are as follows. (1) Regardless of gender, losses of color perception in sensitivity is occurred as aging is proceeded. But the rate of reduction is mitigated compared with the ex-research in Japan because of the promotion of physical health. (2) Human lens coloration was not common until 85 years old and the hue of yellow and red was easily perceived by the older subjects. (3) Yellow is more preferred to other colors by the elderly and accuracy of yellow-color perception is higher than that of blue-color. (4) It is especially hard for the elderly to perceive the difference between pure blue and mixture of blue-green. Therefore blue and blue-green should not be adopted simultaneously in senior housing environment. Except for the space which specially requires carefulness, various color preferred by the elderly should be applied to the senior housing environment to satisfy their psychological condition and provide the vitality of life.

• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.249-258
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• 1998

This study was researched the state and problem of the soft contact Lens wear by the history and inverted microscopy. The results was as follows; 1. The first use of contact lens wear was the 15 years and the last use was the 26 years. The first age of most contact lens wear was the 19 years. 2. In the almost contact lens wearers, the first visual test was the optical shop. 3. At present, almost soft contact lens purchase the optical shop 4. At present, most contact lens wearer like a soft type. 5. At present, most soft contact lens were a domestic production, and some subjects were foreign country production, but some subjects were unknown. 6. After contact lens wear, most subjects don't known the corrected visual acuity, especially, almost people don't known the binocular visual acuity. 7. At present, on soft contact lens color, the teens like the non-color contact lens, twenties like the color contact lens, but thirties was not known. 8. On the advantage of soft contact lens knowledge, most teens and twenties were only one, thirties was unknown. 9. On the disadvantage of soft contact lens knowledge, most teens and thirties were only one, twenties were two. 10. On the side effect of soft contact lens wearer, teens was one, and twenties and thirties don't known. 11. On the main symptoms of soft contact lens wearer, total kinds were seven, On these kinds, most subjects were not symptoms, the next order was unknown on the symptom. But, On the symptoms, the main symptoms was the pain and dry eye. 12. At present, the research on the surface morphology of soft contact lens by inverted microscope, the lens repture, lens folding, foreign body immersion and etc were present. Above the study, most contact lens was soft lens, and the purchase was the optical shop, on the other hand, the knowledge of soft contact lens and visual acuity was few. As a results, On the practical problems of soft contact lens wear, the optician have to the soft contact lens treatment and aftercare by law and educational supporting.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.17-21
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• 2001

We analyzed the luminance in the visual light region and the size of pupil by the luminance to estimate an UV-A line cut efficiency in the lens. The size of pupil by the luminance(L) was given by ${\Phi}=d-e{\cdot}tanh(f{\cdot}logL)$ and the transmittance efficiency value of a size of pupil was given by $T_r(r)=1-gr^2+hr^4$. We derived the absolute cut efficiency value ${\alpha}$ and the exclusion index $b=(1-{\alpha}){\times}100%$ about the UV-A in the $320{\sim}400nm$ regions. The ${\alpha}$ and b values were obtained respectively 0.018, 0.31, 0.273, 0.153 and 98, 69, 72, 85% of Uv-cut Lens, CR-39, red color and blue color.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.134-137
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• 2010

An LED sensor luminaire for visual function improvement necessitates the control algorithm for light level adjustment and the appropriate lens design. The control algorithm adapts to surround lighting condition, and thus has the advantages of energy saving and glare reduction. The multi-cell lens design improves color temperature uniformity and spatial light distribution of the luminaire. Experimental and simulated results show that this approach contributes noticeably to energy saving and color temperature uniformity of the LED sensor luminaire.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.1
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• pp.47-51
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• 2016

Purpose: The purpose of this study was to investigate the change of contrast sensitivity by prescribing tinted lenses and to provide the clinical manual. Methods: Contrast sensitivity was measured for twenty adults with normal vision while they wore yellow, orange and green tinted lenses. To measure contrast sensitivity, the 5 spatial frequencies (2, 4, 6, 8 and 10 cpd) were used for 33 ms and 233 ms, respectively. Results: The contrast sensitivity was overall higher with 233 ms than 33 ms (p<0.05). The peaks of contrast sensitivity with 33 ms and 233 ms were 1.75 log unit with the yellow lens and 1. 85 log unit without the color respectively. However, there was no significance between the yellow and orange tinted lens (p>0.64) Conclusions: Yellowish tinted lens that reduces chromatic aberration and the scattering is prescribed for the various purposes to improve visual functions. Before prescribing tinted lens, identifying characteristic of user and tinted lens for cut off wavelengths is recommended.