• The Journal of Advanced Prosthodontics
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• 제4권2호
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• pp.93-96
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• 2012

PURPOSE. The objective of this study was to compare the light transmittance of zirconia in different thicknesses using various light curing units. MATERIALS AND METHODS. A total of 21 disc-shaped zirconia specimens (5 mm in diameter) in different thicknesses (0.3, 0.5 and 0.8 mm) were prepared. The light transmittance of the specimens under three different light-curing units (quartz tungsten halogen, light-emitting diodes and plasma arc) was compared by using a hand-held radiometer. Statistical significance was determined using two-way ANOVA (${\alpha}$=.05). RESULTS. ANOVA revealed that thickness of zirconia and light curing unit had significant effects on light transmittance ($P$ <.001). CONCLUSION. Greater thickness of zirconia results in lower light transmittance. Light-emitting diodes light-curing units might be considered as effective as Plasma arc light-curing units or more effective than Quartz-tungsten-halogen light-curing units for polymerization of the resin-based materials.

• 폴리머
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• 제36권5호
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• pp.662-667
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• 2012

평판 디스플레이에 사용되는 PET 필름의 광학적 특성을 알아보기 위하여 필름 표면 굴절률, 필름 표면조도 및 필름 내부입자가 광투과율에 미치는 영향을 알아 보았다. 필름표면에 굴절률이 낮은 코팅층을 형성함에 따라 필름의 광투과율이 향상되었고, 최대의 광투과율을 가지는 코팅두께가 있음을 확인하였다. 표면 거칠기의 영향에 대해서는 표면조도를 나타내는 Ra를 입사 파장의 1/4 이하로 조절한 경우 광손실이 발생되지 않았다. 필름 내 무기입자는 입사된 광의 흡수 및 산란을 발생시켜 광손실을 증가시켰다.

• 한국안광학회지
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• 제19권2호
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• pp.135-143
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• 2014

목적: 국제표준에서 규정한 청색광위험함수를 도입하여 청색광차단렌즈에 대한 청색광차단율과 시감투과율을 평가한다. 방법: 8개사 총41종의 청색광차단렌즈에 대한 청색광차단율과 시감투과율을 구하기 위해 UV-VIS 분광광도계로 380~780 nm 범위에서의 분광투과율을 측정하였다. 청색광차단율은 ANSI Z80.3:2010 및 ISO 13666(한국표준 KS B ISO 13666:2004)에서 규정된 청색광위험함수를 도입하여 산출하였다. 결과: 전체 렌즈에 대한 청색광차단율 범위는 9.3%~96.8%, 투과율 범위는 53.5%~92.7%, 시감투과율 범위는 58.0%~98.1%이었다. 전반적으로 코팅 청색광차단렌즈는 시감투과율이 높은 경향이 있었고, 착색 청색광차단렌즈는 청색광차단율이 높은 경향이 있었다. 결론: 렌즈분광분포곡선의 분석으로부터 청색광차단렌즈의 성능을 향상시킬 수 있는 가능성이 있음을 확인할 수 있었다. 제조업체는 국제표준의 규정에 맞춰 성능을 평가할 수 있는 자체기술을 확보할 필요가 있다.

• Current Optics and Photonics
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• 제4권2호
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• pp.141-147
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• 2020

To understand the cause of the high light transmittance of the human eye, the optical effects of the collagen fibers of the stroma layer, which constitute the majority of the cornea, were analyzed. These collagen fibers, approximately 20 nm in diameter, have a regular arrangement. Accordingly, the optical properties of the collagen fibers and the fiber layer were analyzed by simulation. A standing wave was formed in the incident space by the overlapping incident light and the light reflected by the plate. In addition, it was confirmed that when the collagen fibers are arranged in a layer, the light transmittance periodically changes, depending on the number of fiber layers. The standing wave was formed in the incident space, and the light's intensity distribution was changed by the nanoscale collagen fibers in the section with the collagen layer, which affected the transmittance. To explain this phenomenon, the collagen fiber was defined as a second light source, and an attempt was made to describe the simulation results in terms of overlap of the incident light with the light emitted from the collagen fiber.

• 한국산학기술학회논문지
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• 제10권11호
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• pp.3427-3433
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• 2009

본 연구는 착색렌즈의 광투과율에 따른 명소시 대비감도의 변화를 분석하여 색렌즈를 착용할 때 색상에 따른 적절한 광투과율 기준을 제시하고자 하였다. 정상 시기능을 가진 남자 24명과 여자 13명을 대상으로, 광투과율 80~90%, 60~80%, 43~60%, 30~43%로 착색된 4개의 색렌즈(회색, 갈색, 적색, 녹색)를 순서대로 착용시키고 F.A.C.T. 시표를 이용하여 대비감도 검사를 실시하였다. 검사 결과, 광투과율이 감소될수록 대비감도는 감소되었고, 시감도는 갈색이 가장 높고 적색이 가장 낮은 것으로 나타났다. 대비감도 검사결과를 고려한 색상별 권장 광투과율은 갈색, 회색과 녹색 38% 이상, 적색 52% 이상인 것으로 나타났다. 이러한 결과들로 보아 일상생활에서 눈을 보호할 목적으로 색렌즈를 선택할 때 색상과 그 색상에 적절한 광투과율이 고려되어야 한다.

• 한국재료학회지
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• 제28권8호
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• pp.452-458
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• 2018

This research is conducted to create a functional hydrogel ophthalmic lens containing nanoparticles. Carbon nanoparticles and PEGMEMA are used as additives for the basic combination of HEMA, MA, and MMA, and the materials are copolymerized with EGDMA as the cross-linking agent and AIBN as the thermal initiator. The hydrogel lens is produced using a cast-mold method, and the materials are thermally polymerized at $100^{\circ}C$ for an hour. The polymerized lens sample is hydrated in a 0.9 % saline solution for 24 hours before the optical and physical characteristics of the lens are measured. The refractive index, water content, contact angle, light transmittance, and tensile strength are measured to evaluate the physical and optical characteristics of the hydrogel lens. The refractive index, water content, contact angle, UV-B light transmittance, UV-A light transmittance, visible light transmittance, tensile strength and breaking strength of the hydrogel lens polymer are 1.4019~1.4281, 43.05~51.18 %, $31.95{\sim}68.61^{\circ}$, 21.69~58.11 %, 35.59~84.26 %, 45.85~88.06 %, 0.1075~0.1649 kgf and 0.1520~0.2250 kgf, respectively. The results demonstrate an increase in refractive index, tensile strength and breaking strength and a decrease in contact angle and light transmittance. Furthermore, the visible light transmissibility is significantly increased at PEG 10 %. It is clear that this material can be used for high-performance ophthalmic lenses with wettability, ultraviolet ray blocking effect, and tensile strength.

• KIEAE Journal
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• 제12권2호
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• pp.53-58
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• 2012

Daylight is one of the most critical factors that can be utilized for architectural spaces; compared to artificial light, it is a sustainable energy source without the cost of electric energy and offers a more natural feeling to the visitors in the building. To make the space quality better, many architects have tried to predict daylight performance during the design process. The aim of this study is to evaluate the daylight transmittance efficacies of the five shapes - Flat, Pyramid, Dome, Barrel Vault. Ridge - of skylights. The results of this study indicated that the differences of transmittance efficiency among various skylights were less than 4.6% except the flat shaped skylight. Therefore, this study shows that there were no big differences of the daylight transmittance efficacies among the shapes of skylights.

• Restorative Dentistry and Endodontics
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• 제43권2호
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• pp.22.1-22.9
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• 2018

Objectives: To evaluate and compare light-transmittance in dental tissues and dental composite restorations using the incremental double-layer technique with varying layer thickness. Materials and Methods: B1-colored natural teeth slabs were compared to dental restoration build-ups with A2D and B1E-colored nanofilled, supra-nanofilled, microfilled, and microhybrid composites. The enamel layer varied from 0.3, 0.5, or 1.2 mm thick, and the dentin layer was varied to provide a standardized 3.7 mm overall sample thickness (n = 10). All increments were light-cured to $16J/cm^2$ with a multi-wave LED (Valo, Ultradent). Using a spectrophotometer, the samples were irradiated by an RGB laser beam. A voltmeter recorded the light output signal to calculate the light-transmittance through the specimens. The data were analyzed using 1-way analysis of variance followed by the post hoc Tukey's test (p = 0.05). Results: Mean light-transmittance observed at thicker final layers of enamel were significantly lower than those observed at thinner final layers. Within 1.2 mm final enamel resin layer (FERL) thickness, all composites were similar to the dental tissues, with exception of the nanofilled composite. However, within 0.5 mm FERL thickness, only the suprananofilled composite showed no difference from the dental tissues. Within 0.3 mm FERL thickness, none of the composites were similar to the dental tissues. Conclusions: The supra-nanofilled composite had the most similar light-transmittance pattern when compared to the natural teeth. However, for other composites, thicker FERL have a greater chance to match the light-transmittance of natural dental tissues.

• 대한시과학회지
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• 제20권4호
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• pp.561-568
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• 2018

목적 : 각막실질 내 다발 구조로 이루어진 콜라겐섬유의 크기와 규칙적인 배열은 투명성과 매우 밀접한 상관성을 가지고 있다. 시뮬레이션을 이용하여 배열구조 및 콜라겐섬유층 두께에 따른 광투과율의 변화를 확인하고자 하였다. 방법 : 시뮬레이션 소프트웨어인 OptiFDTD로 각막실질 내 콜라겐섬유를 정육각형, 육각형, 사각형 및 자유형으로 각각 배열하였고 이에 따른 광투과율을 분석하였다. 사각형 배열에 대하여 시뮬레이션 공간상에 있는 콜라겐섬유의 개수가 동일할 때 밀도변화에 따른 광투과율을 확인하고 콜라겐섬유의 개수와 밀도가 변화할 때 광투과율을 조사하였다. 결과 : 콜라겐섬유의 개수가 동일할 때 사각형, 정육각형, 자유형 및 육각형의 배열구조 순서로 밀도가 작아지고, 섬유층의 두께가 두꺼워진다. 배열구조를 변화시켜 광투과율을 측정한 결과 동일한 위치의 검출기에서 측정된 광투과율은 배열구조에 관계없이 거의 유사하였다. 검출기 D0, D1, D2 및 D3에서 각각 사각형, 육각형과 사각형, 정육각형 및 정육각형 배열구조에서 최대투과율로 나타났으며, 육각형, 자유형, 육각형과 사각형 및 사각형 배열구조에서 최소 투과율로 나타났다. 하지만, 최대 투과율과 최소 투과율의 차이는 1% 이내로 거의 유사하였다. 콜라겐섬유의 개수가 동일할 때 사각형 배열구조에서 밀도변화에 따른 광투과율은 섬유층 두께가 증가할수록 광투과율은 감소하였다. 또한, 두께가 증가하면서 콜라겐섬유의 개수가 감소하였을 때 광투과율이 더 많이 감소하였다. 결론 : 콜라겐 배열구조가 변화하여도 광투과율은 배열구조와 관계없이 거의 유사하게 나타났다. 하지만, 배열구조의 변화에 따라 콜라겐섬유층의 두께가 변화하였고, 두께가 증가할수록 광투과율이 감소하였다. 즉, 광투과율은 배열구조보다는 콜라겐섬유층의 두께와 더 밀접한 관계를 가지고 있음을 확인하였다.

• 대한치과기공학회지
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• 제42권2호
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• pp.65-71
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• 2020

Purpose: To know the transmittance of light when wearing shading goggles and to protect eyes from blue light emitted from dental scanner when using CAD/CAM works or inducing polymerization reactions of dental resin with curing unit and infrared light occurred when melting Dental precious metal and non-precious metal alloys. Methods: By measuring and comparing the average transmittances of blue light, visible light and infrared ight by using UV-Vis Spectrophotometer analysis measuring instrument, I compared 3 GREEN Color Goggles worn when casting Dental precious metal and non-precious metal alloys, and compared each of YELLOW, ORANGE Color Goggles worn when using Dental CAD/CAM scanners and Light Curing(LED) the Dental resin. Results: In blue light range, YELLOW Color Goggles are more effective than ORANGE Color Goggles. In infrared light range, No.12 Goggles are more effective than No.10 and No.11 Goggles. Conclusion: When wearing blue light shading goggles to avoid harmful blue light occurred in using dental scanner and curing light, and when wearing infrared light shading goggles to avoid harmful infrared light during casting, to avoid the Side Effects like transmittance rate of blue light and infrared light goggles becomes too high to block appropriate amount of harmful light or too low that causing lower image clarity.