• Title/Summary/Keyword: Lens power

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The Optical Tolerances' Decision of the Ophthalmic Dispensing for Korean Models (한국형 안경조제의 광학적 허용오차 설정)

  • Kim, YongGeun
    • Journal of Korean Ophthalmic Optics Society
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    • v.3 no.1
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    • pp.189-199
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    • 1998
  • The system for optical tolerances of completion spectacles was made to sum of the accumulated error - the circumstances on composing prescription, the visual-distance, the tilting angle, the losing of a temple, the vertex distance, the axis of toric lens and the sloping of lens etc. It was given by the relation of allowed values size(T) and power(D), $T=T_0e^{-aD}$. Here, $T_0$ is the size of allowed values of plane-lens with power is 0 and ${\alpha}$ is the factor of allowed values. In case of being adopted to new form s tolerance corresponding to RAL 915, for the tolerance is large direction, the factor of allowed values ${\alpha}$ is $0.166(T_0=5.90)$ and for the tolerance is small direction, the factor of allowed values ${\alpha}$ is $0.166(T_0=2.95)$.

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Study on the Labeling Items and Reliability of Spectacle Lens (안경렌즈의 표시사항 및 신뢰성에 관한 연구)

  • Ye, Ki-Hun;Kim, Tae-Hun;Kwon, Young-Seok;Sung, A-Young
    • Journal of Korean Ophthalmic Optics Society
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    • v.11 no.4
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    • pp.323-327
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    • 2006
  • For this study we research investigated the current situation of packing on the labeling items of domestic spectacle lens and reliability of spectacle lens. We use sample which is three hundred and ninety six spectacle lenses of eight company total. Refractive index of each sample in experiment is 1.55~1.56, 1.60~1.61 and 1.67. The percentage of labeling of A company and B company indicated the percentage of labeling of 80%, but The percentage of labeling of two companies indicated only 52.1% and 56.9% seperately. The most companies indicated comparatively a low marking ratio about packing on the labeling items. The results of difference the value of power which is recorded with the value of power which is measurement showed only small value.

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Hybrid (refrctive/diffractive) lens design for the ultra-compact camera module (초소형 영상 전송 모듈용 DOE(Diffractive optical element)렌즈의 설계 및 평가)

  • Lee, Hwan-Seon;Rim, Cheon-Seog;Jo, jae-Heung;Chang, Soo;Lim, Hyun-Kyu
    • Korean Journal of Optics and Photonics
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    • v.12 no.3
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    • pp.240-249
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    • 2001
  • A high speed ultra-compact lens with a diffractive optical element (DOE) is designed, which can be applied to mobile communication devices such as IMT2000, PDA, notebook computer, etc. The designed hybrid lens has sufficiently high performance of less than f/2.2, compact size of 3.3 mm (1st surf. to image), and wide field angle of more than 30 deg. compared with the specifications of a single lens. By proper choice of the aspheric and DOE surface which has very large negative dispersion, we can correct chromatic and high order aberrations through the optimization technique. From Seidel third order aberration theory and Sweatt modeling, the initial data and surface configurations, that is, the combination condition of the DOE and the aspherical surface are obtained. However, due to the consideration of diffraction efficiency of a DOE, we can choose only four cases as the optimization input, and present the best solution after evaluating and comparing those four cases. On the other hand, we also report dramatic improvement in optical performance by inserting another refractive lens (so-called, field flattener), that keeps the refractive power of an original DOE lens and makes the petzval sum zero in the original DOE lens system. ystem.

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A Comparative Study on Ophthalmic Lenses Standards (시력 보정용 안경렌즈의 규격 비교 연구)

  • Kwak, Ho-Won;Yu, Dong-Sik;Moon, Byeong-Yeon
    • Journal of Korean Ophthalmic Optics Society
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    • v.10 no.3
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    • pp.221-228
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    • 2005
  • In order to analyze the difference of lenses production, we measured the refractive power and the thickness of their optical centers using ophthalmic lenses which were distributed at home country and abroad. The home products were manufactured to be next to foreign goods, but there were several cases to exceed acceptable limits and we need to reduce the deviation from measuring values in the same lenses. To get a beat on advanced countries, rearing technical expert, hard quality test and process control and standardization of lenses are essential to home lens industrials.

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Characterization of Surface treatment for Mold materials using optical system of laser heat treatment (레이저 열처리 광학계를 이용한 금형소재의 표면 열처리 특성)

  • Shin, Ho-Jun;Yoo, Young-Tae;Shin, Hyung-Heon;Ro, Kyoung-Bo
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.1542-1547
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    • 2007
  • Laser surface treatment technologies have been used to improve characteristics of wear and to enhance the fatigue resistance for mold parts. The optical lens with the elliptical profile is designed to obtain a wide surface hardening area with a uniform hardness. The objective of this research work is to investigate the influence of the process parameters, such as power of laser and defocused spot position, on the characteristics of laser surface treatment for the case of SKD61 steel and SCM4 steel. From the results of the experiments, it has been shown that the maximum average hardness is approximatly 700${\sim}$780 Hv when the power, focal position and the travel of laser are 1,095 W, 0mm and 0.3 m/min, respectively. In samples treated with lower scanning speeds, some small carbide particles appear in the interdendritic regions. This region contains fine martensite and carbide in proportions which depend on the local thermal cycle.

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Characteristics of Laser Surface Hardening for SM45C Medium Carbon Steel using Continuous Wave Nd:YAG Laser (연속파형 Nd:YAG 레이저를 이용한 SM45C 중탄소강의 레이저표면경화 특성)

  • Yoo, Young-Tae;Shin, Ho-Jun;Ahn, Dong-Gu
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.11 s.176
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    • pp.51-58
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    • 2005
  • Laser surface hardening technologies have been used to improve characteristics of wear and to enhance the fatigue resistance for automotive parts. The objective of this research work is to investigate the influence of the process parameters, such as power of laser and defocused spot position, on the characteristics of laser heat treatment for the case of SM45C medium carbon steel. CW Nd:YAG laser is selected as the heat source. The optical lens with the elliptical profile is designed to obtain a wide heat treatment area with a uniform hardness. From the results of the experiments, it has been shown that the maximum hardness is approximatly 780 Hv when the power and the travel speed of laser are 1,095 W and 0.6 m/min, respectively. In addition, the hardening width using the elliptical lens was three time larger than that using the defocusing of laser beam.

The Surface Hardening Characteristics of Hot work Tool Steel by CW Nd:YAG Laser (CW Nd:YAG 레이저에 의한 열간금형 공구강의 표면경화특성)

  • Shin H.J.;Yoo Y.T.;Ahn D.G.;Shin B.H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.219-220
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    • 2006
  • Laser surface hardening technologies have been used to improve characteristics of wear and to enhance the fatigue resistance for mold parts. The objective of this research work is to investigate the influence of the process parameters, such as power of laser and defocused spot position, on the characteristics of laser surface hardening for the case of SKD61 steel. CW Nd:YAG laser is selected as the heat source. The optical lens with the elliptical profile is designed to obtain a wide surface hardening area with a uniform hardness. From the results of the experiments, it has been shown that the maximum hardness is approximatly 740 Hv when the power, focal position and the travel of laser are 1,095 W, +1mm and 0.3 m/min, respectively. In addition, the hardening width using the elliptical lens was three time larger than that using the defocusing of laser beam.

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Characteristics Induction and Laser Surface hardening of SM45C Steel (SM45C강의 레이저표면경화와 고주파표면경화특성)

  • Na Gee-Dae;Shin Ho-Jun;Shin Byung-Heon;Yoo Young-Tae
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.7 s.184
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    • pp.39-50
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    • 2006
  • Laser heat treatment technologies have been used to improve characteristics of wear and to enhance the fatigue resistance for automotive parts. The bjective of this research work is to investigate the influence of the process parameters, such as power of laser and defocused spot position, on the characteristics of laser heat treatment for the case of SM45C medium carbon steel. CW Nd:YAG laser is selected as the heat source. The optical lens with the elliptical profile is designed to obtain a wide heat treatment area with a uniform hardness. From the results of the experiments, it has been shown that the maximum hardness is approximatly 780 Hv when the power and the travel of laser are 1,095 W and 0.6 m/min, respectively. In addition, the hardening width using the elliptical lens was three time larger than that using the defocusing of laser beam.

Characteristics of Surface Hardening for Hot Work Tool Steel using Continuous Wave Nd:YAG Laser (연속파형 Nd:YAG 레이저를 이용한 열간금형 공구강의 표면경화 특성)

  • Shin, Ho-Jun;Shin, Byung-Heon;Yoo, Young-Tae
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.4 s.193
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    • pp.57-67
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    • 2007
  • Laser surface hardening technologies have been used to improve characteristics of wear and to enhance the fatigue resistance fur mold parts. The objective of this research work is to investigate the influence of the process parameters, such as power of laser and defocused spot position, on the characteristics of laser surface hardening for the case of SKD61 steel. CW Nd:YAG laser is selected as the heat source. The optical lens with the elliptical profile is designed to obtain a wide surface hardening area with a uniform hardness. From the results of the experiments, it has been shown that the maximum average hardness is approximatly 780 Hv when the power, focal position and the travel of laser are 1,095 W, 0mm and 0.3 m/min, respectively. In samples treated with lower scanning speeds, some small carbide particles appear in the interdendritic regions. This region contains fine martensite and carbide in proportions which depend on the local thermal cycle.