• 조명전기설비학회논문지
• /
• 제27권10호
• /
• pp.15-20
• /
• 2013

In this paper, wireless power transfer system using the magnetic resonance was designed and applied to LED lighting for implementation of wireless lighting. This lighting was made by the converted DC driving type and the direct AC driving type. In the former, transferred AC power was rectified into DC and regulated to the specified voltage value, which leads to produce the loss at the rectifying and regulating circuit. In the latter, wireless-transferred AC power was directly applied to LED, which get rid of the loss derived from the additional circuit. For the efficiency-comparison between the former and the latter, the power at each stage was measured when the same optical output radiated from LED lighting part. The result revealed that the direct AC driving type had 18% higher efficiency than the DC driving type and confirmed that LED lighting using magnetic resonance wireless power transfer system can be efficient by direct AC power supply. And the direct AC driving type had the simple circuit structure and the simple LED lighting formation, so this can leads to various application.

• Journal of Information Display
• /
• 제11권2호
• /
• pp.45-48
• /
• 2010

A direct-lit liquid crystal display that does not use color filters is proposed. A backlight unit that employs compartmentalized RGB LED and lenticular-lens arrays is used instead of color filters to direct the RGB LED lights into the RGB subpixels. The color-filterless LED backlight design, simulation, and experiment results are presented.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2017년도 추계학술대회
• /
• pp.510-511
• /
• 2017

본 논문에서는 현재 단수명 및 잔고장의 빈도가 높은 LED 조명기의 수명 및 고장 발생을 최소화 하고자 연구를 진행하였으며, 현재 LED 칩의 경우 수명이 반영구적이라고 할 수 있지만, LED 칩의 수명에 비해 LED 조명기의 구동드라이버는 수명이 길지 않다. 최근에는 중국산등의 저가 LED 조명기가 시장에 진입함으로써 많은 소비자로부터 LED 조명기의 인식이 나빠지고 있다. 이러한 문제점을 해결하고자 본 논문에서는 고장의 원인이 되는 LED 구동드라이버 부분에 있는 전해 콘덴서 부분을 제거하여 기존의 구동드라이버 보다 수명이 긴 AC Direct IC를 이용하여 25W급의 LED 조명기를 설계하였다.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2012년도 추계총회 및 학술대회 논문집
• /
• pp.171-171
• /
• 2012

In this study, we fabricated the high-brightness AlGaInP-based red light emitting diodes (LED)s using by direct printing technique and inductive coupled plasma (ICP) reactive ion etching (RIE). In general, surface roughening was fabricated by wet etching process to improve the light extraction efficiency of AlGaInP-based red LED. However, a structure of the surface roughening, which was fabricated by wet etching, was tiled cone-shape after wet etching process due to crystal structure of AlGaInP materials, which was used as top-layer of red LED. This tilted cone-shape of surface roughening can improve the light extraction of LED, but it caused a loss of the light extraction efficiency of LED. So, in this study, we fabricated perfectly cone shaped pattern using direct printing and dry etching process to maximize the light extraction efficiency of LED. Both submicron pattern and micron pattern was formed on the surface of red LED to compare the enhancement effect of light extraction efficiency of LEDs according to the diameter of sapphire patterns.After patterning process using direct printing and ICP-RIE proceeded on the red LED, light output was enhanced up to 10 % than that of red LED with wet etched structure. This enhancement of light extraction of red LED was maintained after packaging process. And as a result of analyze of current-voltage characteristic, there is no electrical degradation of LED.

• 중환자간호학회지
• /
• 제13권2호
• /
• pp.12-23
• /
• 2020

Purpose : This study aimed to evaluate the clinical outcomes of direct interhospital transfers (IHTs) of patients with acute aortic syndrome (AAS) led by advanced practice nurses (APNs). Methods : From September 2014 to June 2017, the study retrospectively investigated 183 patients with AAS who were transferred to a high-volume tertiary hospital. Results : One hundred forty-eight (81%) patients were admitted through direct IHTs, and 35 (19%) patients were admitted through non-direct IHTs. The direct IHT group had a significantly shorter time from symptom onset to hospital arrival than the non-direct IHT group (11.4 vs. 32.1 h, p=.043). There were no significant differences in other clinical outcomes, such as peri-transfer status, mortality, hospital length of stay, and readmission, between the two groups. In the direct IHT group, 55% of transfers were led by APNs. There was no significant difference in outcomes between APN- and physician-led transfers. Conclusions : Implementation of direct IHTs markedly shortened the time from symptom onset to hospital arrival in patients with AAS. Finally, direct IHTs can potentially improve the outcomes of patients with AAS, a condition with time-dependent mortality and morbidity. In addition, APNs can effectively lead the direct IHT of patients with AAS.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
• /
• pp.72-75
• /
• 2009

In this paper, we have designed a novel lens for LED's package that can expend the radiation angle of LED from $120^{\circ}$ to $170^{\circ}$ successfully. At the same brightness and uniformity condition of 37" LED BLU system, using novel lens LED package can be reduced amounts of LED 40% or thickness of BLU 30% respectively. Besides, the power consumption of BLU also can be reduced 25%.

• 한국정보전자통신기술학회논문지
• /
• 제11권4호
• /
• pp.388-393
• /
• 2018

본 논문은 고효율 리플렉터 일체형 50W급 AC 직결형 엔진을 개발하여 SMPS 사용하지 않고 제품의 소형화 및 경량화를 구현하여 소비자가 편리하게 사용하고, AC Driver의 취약한 부분을 보완하기 위해 다단 바리스터 회로를 설계하여 전자 부품 수량 감소를 통한 원가절감 전해 콘덴서를 사용하지 않는 회로 구성으로 고신뢰성을 구현 하여 LED수명을 증대시켰다. 또한 AC 직결형 구동장치를 IC 반도체로 제작하여 리플렉터 일체형으로 AC 직결형 구동장치를 적용 하여 제작 그 수명을 LED의 온전한 수명을 모두 사용할 수 있는 장치와 발광 다이오드 조명 장치의 제어 회로에 하나 이상의 발광다이오드를 포함하는 여러 개의 발광 다이오드 채널이 직렬로 구성되는 광원을 정류 전압으로 구동하는 발광 다이오드 조명 장치의 제어회로를 제안하였다.

• 디지털융복합연구
• /
• 제14권4호
• /
• pp.419-424
• /
• 2016

본 논문에서는 광학설계 프로그램을 이용하여 LED 광원의 위치 변화에 따른 배광분포에 대하여 연구하였다. 사용한 LED 조명기구는 엣지형의 LED 배열을 이용하였으며 반사판을 중심으로 도광판 및 확산판을 위와 아래에 배치한 구조이다. LED 칩을 반사판 에지 중심에서 위로 1mm, 2mm 및 3mm로 위치를 바꾸어 시뮬레이션 하였다. LED 칩이 중심에 위치한 경우는 전반확산 배광분포를 보였으며 2mm 이상에서는 효율 0.56의 반직접 배광 분포를 보였다. 3mm 위에 LED 칩을 위치시키면 0.31 효율을 갖는 직접 배광분포를 갖는 배광특성을 나타내었다. 도광판은 평면형 보다 칩 위치에서 밖으로 작아지는 쐐기형의 구조에서 더 좋은 효율을 나타내었다. 그리고 반사면에 반구형의 형상을 0.015mm 씩 증가시키며 방사 형태로 배치한 경우는 파워 1.02W, 효율 0.25, 최대광도 0.104W/sr로서 패턴을 형성하지 않은 경우보다 더 우수한 광 특성을 얻을 수 있었다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2011년도 전력전자학술대회
• /
• pp.350-351
• /
• 2011

본 논문에서는 대형 LED lamp용 직렬 공진형 direct ac-dc 컨버터를 제안하였다. 교류상용전원을 통한 LED lamp에 전원 공급 시, 입력전류의 왜곡을 방지하기 위해, PFC ac-dc 컨버터가 적용된다. 하지만 PFC 컨버터의 특성에 따라 회로의 복잡도 및 수용 전력의 한계가 존재한다. 제안된 컨버터는 기존의 전력변환 방식과 다른 형태로서, 교류 쵸퍼(AC chopper)와 직렬공진회로가 혼합된 구성을 가지며, 교류 쵸퍼의 직접 전력 변환을 통해 PFC 회로 구성없이도 고 역률을 획득할 수 있으며, 직렬공진회로를 통하여 제안된 컨버터의 모든 스위치의 영전압 스위칭(ZVS) 턴-온동작을 통해 손실저감을 도모한다. 본 논문에서는 제안된 컨버터의 동작원리를 간단히 설명하고, 250W의 프로토 타입을 통하여 제안된 컨버터의 우수성을 검증한다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2018년도 전력전자학술대회
• /
• pp.522-524
• /
• 2018

A New Direct AC LED Driver has been proposed for wide output power range and precise constant current regulation using an advanced auto commutation topology. The conventional shunt regulation method provides a stepped input current shape by fixed regulation references in the linear regulator of the each channel, which results in poor current regulation and high THD. The conventional method needs to assign a linear regulator in each LED channel so that the number of linear regulator increases when extending the number of channels especially at high power application. The proposed regulation method can drive multiple switches to regulate each LED channel current by a single amplifier with sinusoidal reference so that large number of LED channel can be simply extended with less BOM cost and low THD is obtained with the accurate current regulation thanks to the sinusoidal input current control in the closed loop control. To confirm the validity of the proposed circuit, theoretical analysis and experimental results from a 20-W LED driver prototype are presented.