Light-Extraction Enhancement of Light Emitting Diodes and Organic Light Emitting Diodes by Photonic Crystal Structures
Date Issued
2007
Date
2007
Author(s)
CHANG, TUN-MIN
DOI
zh-TW
Abstract
In this thesis, a flexible and efficient method to calculate light extraction
efficiency of light-emitting device is developed. This method is primarily
based on finite-difference time-domain ( FDTD) method aided with
Fourier analysis to obtain the intensity of the target frequency. Energy
through all angles or positions is summed up to evaluate total extraction
efficiency.
LEDs ( light emitting diodes) and OLEDs ( organic light emitting diodes)
might become one of the primary components in displays and lighting.
However, both suffer low light extraction efficiency. Considering this issue,
this thesis focuses on LED and OLED simulation. Photonic crystal
is applied to LED and OLED for light extraction efficiency improvement.
Numerous parameters are scanned within parameter bounds to evaluate
the best case and the relationship between light extraction efficiency and
each individual parameter, enabling us to understand effects of various
parameters and design considerations.
We define structure without photonic crystals an ”original structure.”
The thesis starts with ordinary rectangular structure. Furthermore, triangular,
semi-circle and circle structures are also taken into consideration.
Finally, simulation results indicate that rectangular structure in LED offers an optimal improvement at three times of the light extraction
efficiency compared with original structure, while rectangular structure
combined with flat plate in OLED offers an optimal improvement
of thirty percent in light extraction efficiency compared with original
structure.
Subjects
有機發光二極體
發光二極體
光子晶體
有限時域差分法
發光效率
方形結構
三角形結構
半圓形結構
圓形結構
light emitting diode
organic light emitting diode
Photonic crystal
finite difference time domain
light extraction efficiency
square structure
triangle structure
semi-circle structure
circle structure
Type
thesis
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