Improvement of LED Performance With an Integrated Thermoelectric Cooling Package

Guorong Sui,Jiajun Chen,Xiumin Gao,Hao Ni,Ning Wang,Yanying Ma

doi:10.1109/access.2020.3004142

Abstract

The high junction temperature for a working light-emitting diode (LED) will lead to a decrease in luminous efficiency, redshift in wavelength, and shortened lifetime. Conventional cooling methods such as air cooling and water cooling cannot meet the heat dissipation requirements of highly integrated high-power LED cooling systems. A thermoelectric cooler (TEC) has the characteristics of small size, long life, light weight and high reliability, which can effectively reduce the operating temperature of an LED, obtain higher luminous efficiency and improve its service life. In this paper, LED cooling systems with integrated TEC packaging are studied by experiments. Through the comparison of RGBW LED, the influence of temperature on LED is observed, especially the optical characteristics such as spectrum, irradiance and CRI. By observing the board temperature and regulation of optical parameters, the optical characteristics of an LED with an integrated TEC thermal package are significantly improved. For RGB LEDs cooled by a TEC and large-sized heat sink, the wavelength of the red LED is restored by 5 nm. In the case of a white LED cooled by a TEC with a small-sized heat sink, the illuminance is increased by 3 times from 26,768.93 Lux to 82,962.79 Lux with TEC power increased from 0 W to 14.4 W. As an effective refrigeration device for LEDs, a TEC can supply an extra performance regulation method for realizing a controllable cooling environment. By integrating RGBW LEDs with a TEC, this study provides a solution for LED heat dissipation and studies TEC temperature control for the optical performance of LEDs to provide a basis for adjusting the optical performance of LEDs through a TEC.

Highlights

Light-emitting diodes (LEDs) are compound semiconductor lighting devices, which have been regarded as one of the most valuable light sources in the 21st century due to their many incomparable advantages over other conventional counterparts [1]
LED chip cooling by a thermoelectric cooler (TEC) through experimental methods is studied in this paper, and the optical characteristics of the RBGW LEDs such as spectrum, irradiance, color rendering index (CRI) and other optical characteristics are measured and analyzed
When the LED is cooled by a TEC and large-sized heat sink, the working board temperature of the LED is only 17 ◦C

Summary

INTRODUCTION

Light-emitting diodes (LEDs) are compound semiconductor lighting devices, which have been regarded as one of the most valuable light sources in the 21st century due to their many incomparable advantages over other conventional counterparts [1]. The optical characteristics of an LED are improved and the luminous flux is increased due to a decrease in the junction temperature with enhanced thermoelectric cooler (TEC) cooling power. Due to the varying temperature dependence of the emissivity of the spectral channels (red, green, blue), the summarized optical spectrum from such a light source will be changed with temperature variation To solve this problem, some cooling solutions are employed in high-power LED applications, such as use of a fan, heat sink and heat pipe. By observing the junction temperature and the change in the optical parameters, such as wavelength, CCT, CRI, light intensity, and illumination, the optical characteristics of the LED under the integrated TEC thermal package were significantly improved.

HEAT DISSIPATION EXPERIMENT

RESULTS AND DISCUSSION

CONCLUSION