Development of High-Image-Quality and High-Performance Top-Emitting Organic Light-Emitting Devices
Date Issued
2007
Date
2007
Author(s)
Yang, Chih-Jen
DOI
en-US
Abstract
Organic Light Emitting devices (OLEDs) have been the subjects of intense investigation in recent years due to their applications in efficient, large-area and full-color displays. A general OLED usually consists of highly reflective metal films exhibits rather strong ambient-light reflection which reduces the contrast of the display. To enhance the image quality of the display, polarizers or filter films may be laminated on the surface of the display panel to reduce reflection of ambient illumination. However, such approaches reduce the device performances of the device because of the low-reflection characteristics of the contrast enhanced films. Furthermore, photon energies of incident ambient light and significant portion of OLED internal radiation are simply absorbed and wasted.
In this thesis, we developed various OLEDs structures for achieving high performances and high image quality. We first describe the development of high-contrast top-emitting OLEDs. The devices are readily compatible with the processing of active-matrix backplanes and active-matrix OLED displays incorporating such high-contrast top-emitting OLEDs were demonstrated. We then report the integration of OLEDs with solar cells, which not only exhibits a contrast superior to the conventional polarizer approach but also is capable of recycling both incident ambient illumination and internally generated OLED emission. We also examine the combination of polarized OLEDs and waveplate/polarizer for achieving high-contrast and high-efficiency devices.
To improve the device efficiency, we show that microcavity top-emitting OLEDs integrated with microlenses may provide a universal approach for simultaneously achieving all the desired nice characteristics. Since the microlenses can be fabricated separately and then laminated on the microcavity OLED, this approach is simple, effective and highly compatible with OLED fabrication.
Subjects
有機發光元件
上發光型
微共振腔
低反射
能量回收
OLED
Top-emitting
microcavity
low-reflection
high-contrast
energy recycling
Type
thesis
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