Se-Il Lee

Analysis of Thermal Properties in LED Package by Via-hole and Dimension of FR4 PCB

In this study, the heat transfer capability have been improved by using via-holes in FR4 PCB, when the LED lighting is designed to solve the thermal problem. The thermal resistance and junction temperature were measured by changing the dimension of FR4 PCB and size of via hole. As a result, when the dimension was increased initially, the thermal resistance and junction temperature was decreased rapidly, the ones was stabilized after the dimension of 200 (mm 2 ). Also, the light output was improved up to maximum 17% by formation of via-hole and expansion of dimension in FR4 PCB. Therefore, the thermal resistance and junction temperature could be improved by expansion of PCB dimension and configuration of via-hole ability.

Analysis of Thermal Properties in LED Package by Via hole of FR4 PCB

The efficiency of LED package is increasing by applying the high power, and a existing lighting is changing as the LED lighting. However, many problems have appeared by heat. Therefore, in order to solve thermal problems, LED lighting is designing in several ways, but the advantages of LED lighting is fading due to increase the prices and volumes. In this study, we try to improve the thermal performance by formation of via holes. The junction temperature and thermal resistance in the FR4-PCB with via-holes of 0.6[mm] was excellent in experiment and FR4-PCB with Via-holes of 0.6[mm] was excellent in simulation without solder. Further, the thermal resistance and the optical properties can be improved through a formation of via-holes.

Measurement of Junction Temperature in High Power LED Module with Property Analysis of Single Package

Department of Electrical & Information Engineering, Wonkwang University, Iksan 570-749, Korea(Received September 27, 2010; Revised October 28, 2010; Accepted November 3, 2010) Abstract: The temperature of junction in LED affects the life time and performance. however, the measurement of junction temperature in module is very difficult. In this paper, to measure the junction temperature in LED module, optical and electrical properties is measured in single package in temperature from 25 [℃] to 85 [℃], and then junction temperature can is estimated in module with measuring the average voltage of single package. As results, the junction temperature of single package is measured the temperature of 61.2 [℃] in ambient temperature, also, the junction temperature of LED module is measured the temperature of 72.5 [℃] in ambient temperature. Keywords: LED, Junction temperature, Forward voltage

Analysis of the Thermoelectric Devices' Power Generation Performance for Utilizing the Waste Heat of LED Tunnel Lighting Module

In this paper, we propose the LED(Light-Emitting-Diode) emergency lighting in a tunnel by using the thermoelectric devices. To achieve high generated power, thermoelectric device should be have high Seebeck coefficient and small contact area. Also, we reveal that a moderate heatsink required for high generated power. From the waste heat of LED tunnel lighting module (25W), the generated power was 0.062W by thermoelectric device, and it could illuminate for 1hour after charge the battery of emergency lighting during about 101hours.

Thermal Design of High-power 5 Watt LEDs-based Searchlight

The heat dissipation conditions of high-power 5 watt LEDs-based searchlight modules were optimized with varying LED bar`shape, materials, and ambient temperature. The LED junction temperature was estimated by using Computational Fluid Dynamics simulation. The optimal heat dissipation conditions were found as follows; LED bar` shape: L

A Study of Characteristics of the LED Heat Dissipation According to the Changes in Composition of Die-casting Aluminum

Because of the development of LED technology, products due to high output and compact, the material with high thermal conductivity has been developed. Now that heat radiating part of the LED lamp is currently used for die casting of aluminum. The development of aluminum with excellent thermal conductivity is required. In this study, we measured the thermal properties and compared them while we produced the alloy by changing the component of die casting aluminum. From this study, the thermal conductivity and thermal resistance of the developed alloy were superior to die casting aluminum.