Feedback circuit for organic LED active-matrix display drivers
Name
51480029-MIT.pdf
Description
Full printable version
Size
2.29 MB
Format
Adobe PDF
Checksum (MD5)
0867cf904613d7a06b375bc114f2d7fc
Author(s)
Lisuwandi, Eko T., 1977-
Advisor(s)
Charles G. Sodini and Vladimir Bulovic.
Alternative Title
OLED Feedback circuit and demonstration system
Date Issued
2002
Publisher
Massachusetts Institute of Technology
Abstract
A feedback circuit for an Organic Light Emitting Diode (OLED) based display is proposed and demonstrated. An OLED-based flat panel display is brighter, much lower power, has no viewing angle limitation and potentially cheaper compared to available Liquid Crystal (LC) based displays. Despite these advantages, an OLED-based display is not widely commercialized mainly due to its short practical lifetime. The I-V characteristics of the individual OLED pixels vary over time, temperature and processing-dependent parameters. Moreover, the variation is not uniform across an array of OLED pixels, causing OLED based displays to lose brightness accuracy after a few thousand hours of operation. The proposed feedback circuit is used to compensate for the non-uniformities in the individual OLED characteristics. The resulting display leverages the beneficial aspects of OLED display technology, while maintaining pixel uniformity and grayscale reproducibility. A demonstration system is built proving the feasibility of a flat panel display using direct optical feedback. The feedback loop monitors the output light level using a sensor and adjusts the current fed to the pixels to set the output light power to a digitally set reference level. The system shares a single feedback loop among a number of pixels, saving power and real estate. The demonstration system consists of a 5x5 array of LEDs, a CMOS camera, analog pixel circuitry, driver and feedback loop, as well as a digital controller. The demonstration system also shows the feasibility of time-sharing a feedback loop among a number of output devices.
Description
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.
Includes bibliographical references (leaves 44-45).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Subjects
Electrical Engineering and Computer Science.
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
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