Prototyping and Medical Application of Spectrally Tunable LED Light Source

( Hideaki Haneishi ),( Yoko Kurabuchi ) 한국감성과학회 2019 한국감성과학회 국제학술대회(ICES) Vol.2019 No.-

Currently many different color LEDs (light emitting diode) are commercially available. By attaching these LEDs to a board and controlling the light intensity of each LED, we can realize a so-called spectral tunable light source. Compared with a conventional tunable light source using a white lamp such as xenon lamp and grating, LED-based tunable light source is cost effective. We built a prototype of spectrally tunable LED light source (STLED) and are looking for its application to the medical field. In such a field, visual diagnosis is one of the most important ways for evaluation. Observing tissue structure is effective for improving precision of surgery. We focused on an emphatic illuminant which brought a fine view of micro blood vessel structures. In this paper, we simulated the illuminant and evaluated it by subjective evaluation. In an evaluation experiment, to compare two illuminant conditions, a conventional and the emphatic illuminant, 14 LEDs fixed to the light unit were spectrally adjusted to demonstrate the two illuminants. We set a rat cecum as a target to observe the structure of micro blood vessels. The effectiveness of the emphatic illuminant was confirmed by ratio of detected blood vessel region to the ground truth.

Stabilizing color shift of tandem white organic light-emitting diodes

조현수,송진욱,권병화,최수경,이현구,주철웅,안성덕,강승열,유승협,문제현 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.69 No.-

One drawback of white organic light-emitting diodes (WOLEDs) is the white angular dependence (WAD). Aimed to suppress the WAD of tandem WOLED to a negligible degree, we investigated the effect of optical resonance and probed various scattering structures. In a two-tandem configuration, the emissive layer physically remote from the reflective metal electrode is causing detrimental WAD. By combining an external nanoparticle based volumetric scattering film and an internal random nanostructure, it was possible to suppress the WAD of tandem WOLED to a value as low as 0.005, which is indistinguishable to human eyes.

건식이중바닥구조의 중량충격음에 대한 실험적 평가

연준오(Yeon, Junoh),김경우(Kim, Kyoungwoo),최현중(Choi, Hyunjuong),양관섭(Yang, Kwanseop),김경호(Kim, Kyungho) 한국소음진동공학회 2013 한국소음진동공학회 논문집 Vol.23 No.1

The 1st assessment(performance test) was applied to assure the floor impact sound performance for developing the dry double-floor with the change of rubber hardness of the upper panel's support and the ceiling structure of the sub-floor. Depends on the change of the rubber hardness in sub-structure, the heavy-weight sound impact value is improved up to 3 dB, and the light-weight sound impact value is moved up to 21 dB, comparing with the bare-slab. Also, the improved value for the floor impact sound conjugating with the sub-floor's ceiling was 5 dB. Based on this result, the 2nd assessment(performance test) was made the state that the rubber hardness of the sub-floor support was ranged between 50 and 70 for considering the stability of walking patients. In addition to this process, the assessment was carried out with a variety of ceiling structure applied to the dry double-floor structure with the air flow system on the sub-floor's ceiling. The result for the 2nd assessment proved that TYPEII-3 had the better sound reduction performance in the heavy-weight impact sound test than other types, and also for the light-weight impact sound TYPEII-3 had the 29 dB sound reduction performance overall. Henceforth, based on the result the research for the sound reduction performance from the floor impact sound shall be ongoing process as well as the development of a double-dry floor and a sound reduction ceiling to suitable on the field.

유연 및 AVR 디스플레이 광원을 위한 나노 어레이 구조 개발

김제원 조선대학교 공학기술연구원 2024 공학기술논문지 Vol.17 No.1

The nano-sized structures were fabricated by forming patterned nano-molds different from the conventional nano-structure fabrication methods. In order to form a nano-mold structure, a silicon oxide layer was applied and a reactive etching process was used in a semiconductor process. It is possible to create a nanorod structure capable of controlling the pitch size with a nano-mold formed through pattern formation and etching processes. In the conventional two-dimensional planar structure, nitride grows in the c-crystal plane (0001). Therefore, electrons and holes are spatially separated due to a polarization effect, thereby preventing effective recombination. On the other hand, when the light emitting layer is grown on the side of the nanorod, the nonpolar nitride can be grown on the m-crystal plane (10-10) rather than on the c-crystal plane. The formation of the light emitting layer based on the nonpolar nitride can suppress the polarization effect generated in the nitride of the polarity, and thus it is expected that the recombination of electrons and holes can be strengthened.

다중 슬릿빔를 이용한 대 영역 자유 형상 측정

허은창(Eun-Chang Heo),권민철(Min-Chul Kwon),김원일(Won-Il Kim),김병창(Byoung-Chang Kim) 한국기계가공학회 2008 한국기계가공학회 춘추계학술대회 논문집 Vol.2008 No.-

In heavy industry, 3D surface measurement of large-scale hull pieces is needed for fabrication and assembly. Until now, there is not such an efficient method as a standard ruler on 3D profile measurement of large-scale curvature plates. We suggest an efficient method of 3D profile measurement to obtain the xyz-coordinates of curvature plates. The measurement system comprises multiple line structured laser sources and performs profile measurement by projecting structured light source on the object surface.

스테레오 적외선 조명 및 단일카메라를 이용한 3차원 환경인지

이수용(Sooyong Lee),송재복(Jae-Bok Song) 제어로봇시스템학회 2009 제어·로봇·시스템학회 논문지 Vol.15 No.5

This paper describes a new sensor system for 3D environment perception using stereo structured infrared light sources and a camera. Environment and obstacle sensing is the key issue for mobile robot localization and navigation. Laser scanners and infrared scanners cover 180° and are accurate but too expensive. Those sensors use rotating light beams so that the range measurements are constrained on a plane. 3D measurements are much more useful in many ways for obstacle detection, map building and localization. Stereo vision is very common way of getting the depth information of 3D environment. However, it requires that the correspondence should be clearly identified and it also heavily depends on the light condition of the environment. Instead of using stereo camera, monocular camera and two projected infrared light sources are used in order to reduce the effects of the ambient light while getting 3D depth map. Modeling of the projected light pattern enabled precise estimation of the range. Two successive captures of the image with left and right infrared light projection provide several benefits, which include wider area of depth measurement, higher spatial resolution and the visibility perception.

940-nm 350-mW Transverse Single-mode Laser Diode with AlGaAs/InGaAs GRIN-SCH and Asymmetric Structure

곽정근,박종근,박종현,백기종,최안식,김태경 한국광학회 2019 Current Optics and Photonics Vol.3 No.6

We report experimental results on 940-nm 350-mW AlGaAs/InGaAs transverse single-mode laser diodes (LDs) adopting graded-index separate confinement heterostructures (GRIN-SCH) and p,n-clad asymmetric structures, with improved temperature and small-divergence beam characteristics under high-output-power operation, for a three-dimensional (3D) motion-recognition sensor. The GRIN-SCH design provides good carrier confinement and prevents current leakage by adding a grading layer between cladding and waveguide layers. The asymmetric design, which differs in refractive-index distribution of p-n cladding layers, reduces the divergence angle at high-power operation and widens the transverse mode distribution to decrease the power density around emission facets. At an optical power of 350 mW under continuous-wave (CW) operation, Gaussian narrow far-field patterns (FFP) are measured with the full width at half maximum vertical divergence angle to be 18 degrees. A threshold current (I th ) of 65 mA, slope efficiency (SE) of 0.98 mW/mA, and operating current (I op ) of 400 mA are obtained at room temperature. Also, we could achieve catastrophic optical damage (COD) of 850 mW and long-term reliability of 60°C with a TO-56 package.