Nichia Corporation announced blue Light Emitting Diodes (LED) by
1993. They were widely used in markets by 1996 after combining blue
LED with yellow phosphors to emit white lights. There¡¦re two keys to
utilize LED as replacement light energy; one is to increase the chipset
brightness, while another is to use LED arrays instead of single LED.
Around 15 to 20% of LED illuminant will be transformed to visible light,
while up to 85% of the LED illuminant will be transformed to heat.
Therefore, before there¡¦s obvious breakthrough on LED constructions to
heat, thermal management of LED is relatively important.
The purpose of this research is to do value simulation by slightly
change the construction of low power LED and increase its power (150,
350mA), to investigate the differences of high power LED in thermal
transmission by single LED and LED arrays under different parameters,
and learn if the emitted heat can be tolerated by its key materials. This
research can be used as the reference to design LED products for
According to the analysis result, under environment temperature of 25
to 80 Celsius Degree, the temperatures of a 0.5W LED chipset, mounted
board and packing materials will increase around 3 to 4 Celsius Degrees
when the environment temperature will increase one Celsius Degree. If
we increase the LED chipset power to be 1W, the temperature increase
for chipset and mounted board is around 3 to 4 Celsius Degrees while the
temperature increase for packing materials is 3 to 9 Celsius Degrees.
Regarding high power LED arrays, according to the analysis result, when
the distance between two LEDs is too small, the temperature will increase
dramatically; when the P value (see report content) is over 5mm, per
1mm distance increase, the chipset temperature decrease will become 1 to
2.5 Celsius Degrees from initially 3 to 5 Celsius Degrees. If we further
increase the two LEDs distance, there¡¦ll be no significant effect from
chipset itself but only the mounted board.
|14 August 2007
|Chieh-Li Chen Professor, Yu, Ming-Huei, Yang, Fan-Chiang, Tseng, Yih-Tun
|NSYSU Electronic Thesis and Dissertation Archive
|off_campus_withheld, Copyright information available at source archive
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