• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.8
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• pp.25-33
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• 2017

This paper reports the optical design of the MR-16 lamp series with a LED second lens and an aspherical plano-convex lens suitable for a simple and rapid injection molding fabrication method. The fabrication and performance evaluation of the MR-16 lamp series, which was designed with a narrow angular distribution of luminous intensity, were conducted to replace halogen lamps with LED lamps. Four types of LED lamps were fabricated, which have angular distributions of luminous intensity of $22.4^{\circ}$, $31.1^{\circ}$, $37.3^{\circ}$, and $59.9^{\circ}$ and luminous efficiencies of 76.5 lm/W, 75.2 lm/W, 72.0 lm/W, and 77.8 lm/W, respectively, while their spreading angles with an illuminance uniformity of 81% were $3^{\circ}$, $15^{\circ}$, $22^{\circ}$, and $49^{\circ}$, respectively. After eliminating a yellow tail of the LED lamps using a diffusion sheet, the angular distributions of the luminous intensity were measured to be $20.8^{\circ}$, $31.5^{\circ}$, $37.8^{\circ}$, and $68.7^{\circ}$.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.3
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• pp.323-329
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• 2014

Purpose: To understand the pattern of prescribing contact lenses in Korea from 2010 to 2013. Methods: Four hundred survey questionnaires were randomly posted to Korean Optometric clinics for 4 years. The questionnaire was the same form as a form used for International Contact Lens Prescribing Trend. It was also designed to collect information about the contact lenses prescribed to the first 10 patients after its receipt. Results: 1937 fits were used for the analysis among the four hundred survey questionnaires. The average patient age was $26.2{\pm}7.0$ in 2010, $26.1{\pm}7.6$ in 2011, $24.7{\pm}6.6$ in 2012 and $24.8{\pm}7.2$ in 2013. The patients were mainly women (75%). Of all the soft contact lenses, silicon hydrogel lenses were 18% of fits (17% in 2010, 10% in 2011, 20% in 2012, 24% in 2013). By degine, the percentage of toric design lenses accounted for 17% of soft lenses fits and had increased during 4 years (10% in 2010, 18% in 2011, 16% in 2012, 22% in 2013), and cosmetic contact lens made up for 29% (15% in 2010, 20% in 2011, 40% in 2012, 41% in 2013). Conclusions: The contact lenses wearers were mostly women and the average patient age becomes slightly younger. In relation to the increase in the mumber of younger female contact lens wearers,the percentage of cosmetic lenses prescription was much higher (29%) than the global average (7%), and it has gradually increased for last 4 years. This trend could be related to the growth of beauty market in Korea. By emphasizing on toric lens marketing in manufactures, the prescription rate has been gradually increased.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.2
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• pp.233-239
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• 2012

Purpose: In the study, the change of protein and lipid deposits on soft contact lens by drinking was investigated. Methods: Fifty male subjects wearing soft contact lens were surveyed whether they felt any discomfort induced by drinking or not. Further, 32 male subjects who has no ocular disease drank 190 mL alcohol. The protein and lipid deposits on soft contact lens (etafilcon A material) of subjects were measured after 4 hours later and compared with those of non-drinking subject. Results: When subjects drink alcohol with soft contact lens on, 58% of subjects answered they experienced the change of lens awareness such as stiffness, blurry sight, dryness and so on. The protein deposit on soft contact lens increased an average of $59.3{\mu}g/lens$ by drinking and the case of more than double in protein deposit was reached in 9 eyes. However, the protein deposited on soft contact lens was lysozyme which was unchanged by drinking. The amounts of cholesterol and methyl oleate after drinking were 85.5% (p=0.25) and 52.6% (p=0.002) of non-drinking's indicating some change of lipid deposit on soft contact lens by drinking. Conclusions: The results showed the composition of protein and lipid deposited on soft contact lens was changed due to drinking. Thus, it is suggested that wearing soft contact lens when drinking might be one of the reasons to feel discomfort.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.4
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• pp.455-462
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• 2015

Purpose: To develop more accurate wet measuring system combining the wet cell, automatic lensmeter and the related software for hydrophilic contact lenses and to verify the accuracy of those measuring holder system already available in the market. Methods: Refractive power measurement were done in both a conventional method which has been commonly used in optical shops and a new method which is recently developed in korea. Hydrophilic contact lens of korean brand was chosen as a test material and was tested by water content ratio and by spherical refractive power. Results: When spherical power of -3.00 D contact lens is measured in the newly developed wet cell measurement holder with automatic lensmeter, it reads -3.01 D at water content ratio of 38%. -3.00 D at 45% and -2.98 D at 58%. The same experiment with the Poster soft contact lens wet cell measurement holder maintaining other conditions same resulted in -3.60 D at the water content ratio of 38%, -3.06 D at 45% and -2.46 D at 58%. Conclusions: At the higher water content, the refractive power values measured by both of the wet cell measuring holders are shown lower, and additionally, the new method using the wet cell holder and new software program in a automatic lensmeter showed more accurate readings than conventional Poster soft contact lens wet cell measuring system.

• Journal of the Institute of Convergence Signal Processing
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• v.17 no.1
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• pp.26-31
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• 2016

In this paper, we propose an image quality evaluation system for compact camera module and assess the effect of optical performance improvement for proposed anti-halation disk in small lens. We develop a image quality evaluation system for quality estimation of camera module image. And we also develop a program to control register in image signal processor. Finally the resolution, brightness, and color reproduction performances were evaluated image quality comparison between conventional and proposed camera module using developed quality evaluation system and ISP register control program.

• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.749-754
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• 2009

HEMA (2-hydroxyethyl methacrylate) is a hydrophilic material which is broadly used for ophthalmologic purposes and especially in the manufacture of soft contact lenses. Also, the oxygen transmissibility (Dk/t) is a very important physical characteristic in the evaluation of a material’s adequacy to be used to produce contact lenses. This study used HEMA (2-hydroxyethyl methacrylate), MMA (methylmethacrylate), NVP (Nvinyl-pyrrolidone), the cross-linker EGDMA (ethylene glycol dimethacrylate) for copolymerization, and measured the oxygen transmissibility of the central and peripheral areas of the manufactured general and color contact lenses using the polarographic method. The measurement showed that the decreased amount of oxygen transmissibility of the central and peripheral areas of the contact lenses measured using the polarographic method range between 40.77% and 49.13%, and the oxygen transmissibility of the color contact lens showed a larger decrease due to the effects of the coloring materials.

• Journal of IKEEE
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• v.26 no.3
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• pp.416-421
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• 2022

In this study, we present a fully automated system that combines camera technology with liquid crystal technology to create a polarization camera capable of detecting the partial linear polarization of light reflected from an object. The use of twisted nematic (TN) liquid crystals that electro-optically modulate the polarization plane of light eliminates the need to mechanically rotate the polarizing filter in front of the camera lens. Images obtained using these techniques are imaged by computer software. In addition, liquid crystal panels have been produced in a square shape, but many camera lenses are usually round, and lighting or other driving units are installed around the lens, so space is optimized through the application of a circular liquid crystal display. Through the development of this technology, an electrically switchable and space-optimized liquid crystal polarizer is developed.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.3
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• pp.213-217
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• 2010

Purpose: To emphasize the necessity of post-fitting by follow-up test, the mis-alignment was analyzed after initial wearing of toric soft contact lenses (TSCL). Methods: After trial contact lenses were worn to 87 eyes with myopic astigmatism for 1 week, we observed the alignment of axis mark on trial contact lenses using slit lamp and corrected the rotated axis by method of LARS. After final fitting, rotation ratio, rotation degree and rotation position were analyzed compared to initial prescription divided to amount of cylinderical and spherical powers. Results: Rotation ratio of TSCL's axis was increased as increment of both cylinderical powers and (-)spherical powers. An average of rotation degree was $10^{\circ}{\sim}13^{\circ}$ which was not related to amount of their powers. Rotation position of TSCL's axis was more to temporal than to nasal. Conclusions: Because mis-alignment of axis after TSCL wearing induce the poor sight, adjustment of axial alignment as a result of follow-up must be performed.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.4
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• pp.437-443
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• 2015

Purpose: This study evaluated the optical and physical and characteristics of soft contact lens polymerized with addition of 3-chloropyridine-4-carboxylic acid and 3-fluoropyridine-4-carboxylic acid in the basic hydrogel contact lens material. In particular, the utility of 3-chloropyridine-4-carboxylic acid and 3-fluoropyridine- 4-carboxylic acid as a hydrogel contact lens material was investigated. Methods: In this study, 3-chloropyridine-4-carboxylic acid and 3-fluoropyridine-4-carboxylic acid were used as additives. Also, 2-hydroxyethyl methacrylate, acrylic acid, methyl methacrylate and a cross-linker EGDMA were co-polymerized in the presence of AIBN as an initiator. Results: The physical properties of the produced polymers were measured as followings. The water content of 34.54~37.15%, refractive index of 1.4320~1.4342, tensile strength of 0.2872~0.3608 kgf and contact angle of $57.82{\sim}79.57^{\circ}$, UV-B transmittance of 76.8~82.4% and UV-A transmittance of 84.6~86.6% were obtained respectively. Conclusions: Based on the results of this study, contact lens material containing 3-chloropyridine-4-carboxylic acid and 3-fluoropyridine-4-carboxylic acid is expected to be able to used as a material for high wettability and UV-block hydrogel contact lens.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.1
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• pp.43-49
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• 2014

Purpose: The physical and optical characteristics of hydrophilic contact lens polymerized with addition of glycerin and PVP(polyvinylpyrrolidone) in the basic hydrogel contact lens material were evaluated. Methods: This study used glycerin and PVP(polyvinylpyrrolidone) with the cross-linker EGDMA (ethylene glycol dimethacrylate), HEMA (2-hydroxyethyl methacrylate) and the initiator AIBN (azobisisobutyronitrile) for copolymerization. Results: Measurements of the physical characteristics of the copolymerized material including PVP(polyvinylpyrrolidone) showed the refractive index of 1.4382~1.4288, tensile strength of 0.3446~2542 kgf and water content and contact angle of sample showed the increase of 13.49% and decrease of 21.44% independently. And also, the physical characteristics of the copolymerized material including glycerin showed the refractive index of 1.4330~1.4328, tensile strength of 0.2974~0.2854 kgf, water content 35.58~36.53% and contact angle of sample showed the decrease of 37.64%. Conclusions: Based on the results of this study, the produced copolymers is suitable for conventional lens with high wettability. Also, glycerin minimized the changes of water content and refractive index at the same time, increased the wettability of the hydrogel lens materials.