In particular, when HPCOBLED is of high power, the decrease of luminous flux is larger. An explanation for this result is consumed power on the LED. We proposed HPCOBLED model modified from Hodapp’s model using temperature gradient between p-n junction of device and heat radiator for description of the temperature effect on luminous flux of HPCOBLED. The calculation results for the modified HPCOBLED model match with those experimental values measured by the luminous flux measurement system (VMI-PR-001, Vietnam). | Communications in Physics, Vol. 24, No. 3 (2014), pp. 267-273 DOI: STUDY OF TEMPERATURE EFFECT ON LUMINOUS FLUX OF HIGH POWER CHIP-ON-BOARD LIGHT EMITTING DIODE CAO XUAN QUAN AND VU KHANH XUAN Photometry and Radiometry Laboratory, Vietnam Metrology Institute LUU THI LAN ANH AND VO THACH SON School of Engineering Physics, Hanoi University of Science and Technology E-mail: quancx@ Received 25 July 2014 Accepted for publication 21 August 2014 Abstract. High power chip-on-board light emitting diode (HPCOBLED) is a promising solid state light technology for a variety of lighting applications. In this paper, we study temperature effect on luminous flux of HPCOBLED using VMI-PR-001 system of Vietnam Metrology Institute. The results show that when the case temperature (Tc ) increases, luminous flux decreases. In particular, when HPCOBLED is of high power, the decrease of luminous flux is larger. An explanation for this result is consumed power on the LED. We proposed HPCOBLED model modified from Hodapp’s model using temperature gradient between p-n junction of device and heat radiator for description of the temperature effect on luminous flux of HPCOBLED. The calculation results for the modified HPCOBLED model match with those experimental values measured by the luminous flux measurement system (VMI-PR-001, Vietnam). Keywords: high power chip-on-board light emitting diode (HPCOBLED), luminous flux, integrating sphere. I. INTRODUCTION High power chip-on-board light emitting diode (HPCOBLED) is a big potential candidate for solid state lighting technology in a variety of applications, including indoor and decorative lighting, street lamps, and automotive lighting [1-5]. HPCOBLED presents several advantages over conventional lighting technologies such as follows: (i) long operation lifetime, (ii) low energy consumption, and (iii) environmental protection. However, the actual efficiency and performance of HPCOBLED are highly depended .
