• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4489-4493
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• 2014

LED light driving device has problems in efficiency and heating at higher than 150W. In addition, there is inconvenience in replacing the lighting device to another when W is not the same as the previous one. In this paper, a multi-channel LED light driver, driver embedded driver circuit in a multi-channel structure with a power system in the driver-interlocking structure was designed. With the auto control converter structure with a power efficiency above 93% and power factor above 0.98, the weight of the high efficiency LED lighting-actuating device in driver-interlocking structure, a driver in self-calibrating self-optimization structure. In this paper, at below 10% THD, the existing converter contrast weight was reduced by 40% or more.

• Current Optics and Photonics
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• v.4 no.6
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• pp.477-482
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• 2020

Recently, one of the authors has been reported an optically tunable fiber Bragg grating (FBG) with a photomechanical polymer. It was based on a typical FBG with a downsized diameter of 60 ㎛, coated with azobenzene-containing polymer material. Azobenzene is a well-known reversibly photomechanical stretchable material under ultraviolet (UV) light. The small part of the functional-coating region on the FBG absorbed UV light, which pulled the UV-exposed part of the grating. It was selectable as tunable FBG or tunable chirped FBG, by adjusting the position of UV exposure on the grating. As proof of concept for the tunable FBG device, the characteristics just including UV-induced center-wavelength shift and spectral-width changes of the device were reported. In this paper, we report for the first time that the microactuator makes it possible to control the spectral shape of the FBG reflection, according to the specifications (shape and intensity) of the UV beam that reaches the FBG coated with the azobenzene polymer. In addition, we provide the group-delay profiles for the chirped FBG, so that the sign of its dispersion (normal or anomalous) can be tailored by simply selecting the moving direction of the UV light's displacement in the experiment.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.6
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• pp.49-56
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• 2007

In this paper, the development of excitation light source is proposed for excitation light of the photodynamic therapy of cancer. Since the selection of the wavelength band of excitation light has an interrelation with fluorescence generation according to the selection of a photosensitizer. This study aims at designing and evaluating light source that can stably generate light with various kinds of wavelengths in order to make possible photodynamic diagnosis using a photosensitizer and diagnosis using auto-fluorescence. The light source device was a Xenon lamp and filter wheel, composed of an optical output control through iris and filters with several wavelength bands. It also makes the inducement of auto-fluorescence possible because it is designed to generate a wavelength band of 380-420nm, 430-480nm, 480-560nm. The transmission part of the light source was developed to enhance the efficiency of light transmission. To evaluate this light source device by KFDA#s technical reference, the characteristics of the light output and wavelength band were found.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.11
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• pp.205-210
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• 2014

This is concerned with the technology to display the design on Porcelain and adjust malfunction for moving effect and light intensity by curator. More precisely, the technology makes it possible that the porcelain is connected to Light module which is the device for controlling light emission and rotating rolling plate, etc that are connected to LED light module, optical fiber and controller that is for scenario from the given storytelling. In addition, with a WiFi portable device (Smart-phone, other mobile device). equipped with a scenario programs, information for operation, failure and malfunction can be obtained and analyzed in real-time, and menu color and alarm is alerted when the displaying design is in abnormal status, which makes the early reactions to the status. Furthermore, the collected data can be sent through WiFi network to the device and PC managed by the curator specialized in managing the design on the Porcelain, thus the technology could help the curator who have less knowledge about moving pattern on the Porcelain. There is always a possibility of malfunction due to various condition that are caused by wring-harness when modules are wired-connected. In this research, in order to overcome this problem, we propose a system configuration that can do monitoring and diagnosis with a device for collecting data from LED control module, Light emission sensor and a personal WiFi device. Also, we performed connection between optical Fiber and LED and interlock for the system defined by the definition for information and storytelling scenario.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.713-716
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• 2000

In this study, we present a mobile robot for ultrasonic scanning of weldment. magnetic Caterpillar mechanism is selected in order to travel on the inclined surface and vertical wall. A motion control board and motor driver are developed to control four DC-servo motors. A virtual device driver is also developed for the purpose of communicating between the control board and a host PC with Dual 'port ram. To provide the mobile robot with stable and accurate movement, PID control algorithm is applied to the mobile robot control. And a vision system for detecting the weld-line are developed with laser slit beam as a light source. In the experiments, movement of the mobile robot is tested inclined on a surface and a vertical wall.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.627-627
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• 2013

Recently, most studies concerning inorganic CdSe/ZnS quantum dot (QD)-polymer hybrid LEDs have been concentrated on the structure with multiple layers [1,2]. The QD LEDs used almost CdSe materials for color reproduction such as blue, green and red from the light source until current. However, since Cd is one of six substances banned by the Restriction on Hazardous Substances (RoHS) directive and classified into a hazardous substance for utilization and commercialization as well as for use in life, it was reported that the use of CdSe is not suitable to fabricate a photoelectronic device. In this work, we demonstrate a novel, simple and facile technique for the synthesis of ZnO-graphene quasi-core.shell quantum dots utilizing graphene nanodot in order to overcome Cd material including RoHS materials. Also, We investigate the optical and structural properties of the quantum dots using a number of techniques. In result, At the applied bias 10 V, the device produced bluish-white color of the maximum brightness 1118 cd/$m^2$ with CIE coordinates (0.31, 0.26) at the bias 10 V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.240-240
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• 2009

We developed the low level laser therapy(LLLT) apparatus for external injury cure using a GaAsP Diode. This equipment was fabricated by using GaAsP diode and a microcontroller, and designed to enable us to control light irradiation timer, and frequency. In this paper, the designed device was used to find out how GaAsP diode light source affects the skin wound of RAT. In the experiment, $1cm^2$ wounds on the External injury of RAT were made. Light irradiation RAT and none light irradiation RAT divided, each RAT was irradiated 20 min a day for 9 days. In result, compared with none light irradiation RAT, the lower incidence of inflammation and faster recovery was shown in light irradiation RAT.

• Applied Science and Convergence Technology
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• v.25 no.1
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• pp.1-6
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• 2016

Quantum dots (QDs) are considered as excellent color conversion and self-emitting materials for display and lighting applications. In this article, various technologies which can be used to realize white light emission with QDs are discussed. QDs have good color purity with a narrow emission spectrum and tunable optical properties with size control capabilities. For white light emission with a color-conversion approach, QDs are combined with blue-emitting inorganic and organic light-emitting diodes (LED) to generate white emission with high energy conversion efficiency and a high color rendering index for various display and lighting applications. Various device structures for self-emitting white QD light-emitting diodes (QD-LED) are also reviewed. Various stacking and patterning technologies are discussed in relation to QD-LED devices.

• Journal of Ceramic Processing Research
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• v.13 no.spc2
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• pp.193-197
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• 2012

Oxygen plasma has been treated on the surface of indium-tin-oxide (ITO) to improve the efficiency of the organic light-emitting diodes (OLEDs) device. The plasma treatment was expected to inject the holes effectively due to the control of an ITO work-function and the reduction of surface roughness. To optimize the treatment condition, a surface resistance and morphology of the ITO surface were investigated. The effect on the electrical properties of the OLEDs was evaluated as a function of oxygen plasma powers (0, 200, 250, 300, and 450 W). The electrical properties of the devices were measured in a device structure of ITO/TPD/Alq3/BCP/LiF/Al. It was found the plasma treatment of the ITO surface affects on the efficiency of the device. The efficiency of the device was optimized at the plasma power of 250 W and decreased at higher power than 250 W. The maximum values of luminance, luminous power efficiency, and external quantum efficiency of the plasma treated devices increase by 1.4 times, 1.4 times, and 1.2 times, respectively, compared to those of the non-treated ones.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.53-53
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• 2010

Graphene comes into the spotlight as an emergent device material on account of its high carrier mobility reflecting its massless Dirac fermion behavior. Chemical technique to control reversibly the carrier concentration of semiconducting graphene for the achievement of a large-area graphene device has been strongly required. Here we show that the adsorptions of a metal and a molecule can manipulate the carrier concentration of single-layer graphene, epitaxially grown on SiC, which was directly observed using angle-resolve photoemission spectroscopy. These results will shed light on the researches for the very large scale integration of a graphene device. Furthermore, the carrier concentration changes can be applied to a highly sensitive gas sensor or a detector for an specific binding between an antigen and an antibody.