• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.105-108
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• 2007

Because of energy efficiency and environment-friendly characteristics, demands of white LED are being increased in various fields. White LED is being observed as next-generation light sources to alternate incandescent and fluorescent lamps so that the studies on white LED are being processed continuously. This study investigates technical developments and market movements of white LED to evaluate technical characteristics and to analyze performances data by comparing prototypes of white LEDs. And comparing efficiency of white LED with that of incandescent and fluorescent lamps, this study aimed at presentation of compatible standards for future LEDs.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.1
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• pp.42-46
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• 2011

Light can be divided into ultraviolet rays, visible rays, and infrared rays depending on the wavelengths. Visible rays with specific wavelength are those predominantly used for would treatment. Especially low level laser irradiates into cells, effectively stimulating cellular tissues and activating cellular function. This study was intended to verify the effect of white LED irradiation therapy on wound recovery in animal tests by applying white LED irradiator, which was independently designed and developed to emit beams of similar wavelength to that of a laser. The designed LED Irradiator was used to find out how white LED light source affected the skin wound of SD-Rat(Sprague-Dawley Rat). We divided the participants into two groups; white LED irradiation group which was irradiated 1 hour a day for 9 consecutive days, and none irradiation group. The results showed that the study group had lower incidence of inflammation and faster recovery, compared with the control group.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.356-356
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• 2012

InGaN/GaN로 제작된 Blue chip의 파장에 따른 백색 LED의 성능 저하를 전기적, 광학적 특성을 고려하여 조사하였다. 4가지 파장으로 제작된 백색 LED Sample들은 60 mA, 75 mA, 90 mA의 주입 전류로 장 시간동안 스트레스를 주었다. 또한 형광체가 없는 상태와 있는 상태를 구분하여 패키지의 감쇠 특성을 확인하였다. Blue 피크 파장 437 nm, 주입전류 90 mA, 형광체가 있는 상태와 형광체가 없는 상태에서 패키지의 출력 광세기는 각각 20%, 36%까지 감소하였다. 이는 Blue Chip에서 출력되는 단파장이 페키지 몰드의 노화(황변)현상에 직접적인 영향을 주기 때문이다. 전기적 특성은 Blue chip의 파장영역에 의존하지 않고, 스트레스 시간에 따른 LED내부 저항이 커지는 현상을 확인하였다. 따라서 InGaN/GaN로 제작된 백색 LED의 장 수명을 얻기 위해서는 Blue chip의 출력 파장 영역과 페키지 몰드 재료 특성의 신뢰성 관계가 중요하다.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.2
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• pp.117-122
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• 2016

Purpose: Gingival whitening is one of dental treatment purposes which is close to treating aesthetic disorders. Initial gingival whitening treatment was done by dermabrasion using a high power Diode Laser. However, this treatment method cannot be free from any infection or pain after the treatment. Therefore, we have decided to progress gingival whitening treatment using a low power LED laser. Materials and Methods: The laser was irradiated on pork meat then the safety of output power, temperature change and skin denaturalization was measured. Bison 365 nm LED laser was irradiated on oral mucosal pigment of a 15 - 20 kg beagle for 15 min for 1 - 2 weeks, one or two times each. Any pigment loss was checked through Hematoxyline-Eosin staining. Results: The melanin pigments at the area of 365 nm LED Laser irradiation were decreased. Conclusion: The 365 nm LED Laser proposed in this study is considered to compensate the bleaching effect achieved by either using Diode laser or surgical methods.

• Restorative Dentistry and Endodontics
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• v.29 no.6
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• pp.504-514
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• 2004

This study compared the dentin shear bond strengths of currently used dentin bonding agents that were irradiated with an LED (Elipar FreeLight, 3M-ESPE) and a halogen light (VIP, BISCO). The optical characteristics of two light curing units were evaluated. Extracted human third molars were prepared to expose the occlusal dentin and the bonding procedures were performed under the irradiation with each light curing unit. The dentin bonding agents used in this study were Scotchbond Multipurpose (3M ESPE), Single Bond (3M ESPE), One-Step (Bisco), Clearfil SE bond (Kuraray), and Adper Prompt (3M ESPE), The shear test was performed by employing the design of a chisel-on-iris supported with a Teflon wall. The fractured dentin surface was observed with SEM to determine the failure mode. The spectral appearance of the LED light curing unit was different from that of the halogen light curing unit in terms of maximum peak and distribution. The LED LCU (maximum peak in 465 nm) shows a narrower spectral distribution than the halogen LCU (maximum peak in 487 nm). With the exception of the Clearfil SE bond (P < 0.05), each 4 dentin bonding agents showed no significant difference between the halogen light-cured group and the LED light-cured group in the mean shear bond strength (P > 0.05). The results can be explained by the strong correlation between the absorption spectrum of camphoroquinone and the narrow emission spectrum of LED.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.3
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• pp.55-58
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• 2004

Recently the examples of a lighting design with LED source have increased rapidly, but there are few researches that are related to selecting luminous colors by LED. The research is that respondents operated color blender and got preference colors according to what they made, the colors were measured by chroma meter and marking CIE 1931 chromaticity diagram. Through the results of the research has made group preference for luminous colors. From now on, not only does it seem capable of using a designing a building-lighting to which LED but it will be actively applied to controlling with a digital technology for lighting design.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.329-332
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• 2012

LEDs are using widely in a field of illumination, LCD LED backlight, mobile signals because they have several merits, such as low power consumption, long lifetime, high brightness, fast response, environment friendly. To achieve high performance LEDs, one needs to enhance output power, reduce operation voltage, and improve device reliability. In this paper, we have proposed that the optimum design and specialized process could improve the performance of LED chip. It was showed an output power of 7cd and input supplied voltage of 3.2V by the insertion technique of current blocking layer. In this paper, GaN-based LED chip which is built on the sapphire epi-wafer by selective MOCVD were designed and developed. After that, their performances were measured. It showed the output power of 7cd more than conventional GaN-based chip. It will be used the lighting source of a medical equipment and LCD LED TV with GaN-based LED chip.

• The Journal of the Convergence on Culture Technology
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• v.7 no.1
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• pp.564-569
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• 2021

In this paper, for the typical LED and the tilted LED, when there is no electrode, when 20% absorption (80% reflection) occurs at the electrode, and when 60% absorption (40% reflection) occurs at the electrode, the effect of the absorption at the electrode and the height of the active region on the photon extraction efficiency and the mean photon path length was investigated, and an appropriate height of the active region was proposed. In a typical LED, as the absorption of the electrode increases, the photon extraction efficiency decreases from 18% to 15% and 13%, and the photon extraction efficiency is highest when the height of the active area is located in the center between the two electrodes. In the tilted LED, as the absorption of the electrode increases, the photon extraction efficiency decreases from 38% to 33% and 25%, and the photon extraction efficiency is highest when the height of the active area is located in the center between the two electrodes. The tilted LED can increase the photon extraction efficiency more than twice than that of a typical LED, where photons are trapped inside the chip due to total reflection.

• Congress of the korean instutite of fire investigation
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• 2009.12a
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• pp.53-65
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• 2009

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.856-859
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• 2012

In order to cultivate vegetables in plastic greenhouse or housing facilities it was investigated properties of radiation and functions of LED lamp and proposed application possibility. Against presently existing method of obtaining blue and red colored wave lights needed to plants growing, it was used white LED and red LED to investigate growing conditions as well as brightness and color sense with working condition. And also it was presented lighting system of selective wave functions to promote plant growth.