EPD Paper, April 2007

Project Documents

• CSE561 Modeling and Simulation Project Preliminary Report (.doc)
• Project Slides presented on 5 March 2007 (.ppt)
• Project document as of 5 March 2007 (.doc)

Paper Search

"LCD power model" search on ACM

Display Technologies

General

• > "Qualcomm report on competitive modern display technologies"
• "Display Technologies for Portable Communication Devices", 2002

Liquid Crystal Displays (LCD)

• Liquid Crystal Display (LCD)
• > LCD background
• > Thin Film Transistor (TFT LCD) Overview (plasma.com)
• TFT on Wikipedia
• Active Matrix LCD
• L. Blackwell, "LCD Specs: Not So Swift", PC World, Friday, July 22, 2005

Flexible Displays

Electrophroetic Displays (EPD)

• > Incredible list of papers on EPD and other topics from the Liquid Crystals and Photonics Group at University of Ghent
• Electronic paper prototype
• Electrophoretic technology
• (1.21) B. Comiskey, J. D. Albert, H. Yoshizawa, J. Jacobson, "An electrophoretic ink for all-printed reflective electronic displays", Nature 394, 253-255 (16 July 1998)
• (1.12) A. L. Dalisa, "Electrophoretic Display Technology", IEEE Transactions on Electron Devices, Vol. ED-24, No. 7, July 1977

Some current characterization for electrophoretic suspension fluid.

• (1.13) "Katase, Method and circuit for driving electrophoretic display, electrophoretic display and electronic device using same", U.S. Patent 6961047, 2005
• (1.14) M. A. Hopper, V. Novotny, "An Electrophoretic Display, Its Properties, Model, and Addressing", IEEE Transactions on Electron Devices, Vol. ED-26, No. 8, August 1979

Addressing. With a display thickness of 50micrometer and an average dielectric constant of 5.0, the capacitance per element would be ~0.055 pF.

• (1.15) S. Vermael, K. Neyts, G. Stojmenovik, F. Beunis, L. Schlangen, "A 1-Dimensional Simulation Tool for Electophoretic Displays", Fourth FTW PhD Symposium, Ghent University, 2003
• (1.17) E. Herz, "Electrophoretic Display technology: The beginnings, the improvements, and a future in flexible electronics", Term Paper, MSE542, Cornell University, May 19, 2006
• (1.19) H. Takao, M. Miyasaka, H. Kawai, H. Hara, A. Miyazaki, T. Kodaira, S. W. B. Tam, S. Inoue, T. Shimoda, "Flexible Semiconductor Devices: Fingerprint Sensor and Electrophoretic Display on Plastic", ESSDERC Proceeding of the 34th European, pp. 309-312, September 2004

EPD driver information and pixel level model

Section 3. To compensate for the leakage current, the storage capacitor must be very large; here, the capacitance is 34 pF. A polysilicon TFT is preferable to an amorphous silicon TFT for the switching transistor, because the large capacitor must be charged during the short pixel selection period.

• (1.20) S. Inoue, H. Kawai, S. Kanbe, T. Saeki, T. Shimoda, "High-Resolution Microencapsulated Electrophoretic Display (EPD) Driven by Poly-Si TFTs With Four-Level Grayscale", IEEE Transactions on Electron Devices, Vol. 49, No. 8, August 2002

EPD driven to produce greyscale

I. ...we have reported the world's first active-matrix EPD at an international electron device meeting (IEDM 2000)[12]. Since then, a few displays combining TFTs and microencapsulated electrophoretic materials have also been introduced [13]-[16].

I. Microencapsulated electrophoretic material in this EPD was driven by poly-Si TFTs fabricated with a low temperature process...

• (1.22) K. S. Kim, J. Y. Lee, B. J. Park, J. H. Sung, I. Chin, H. J. Choi, J. H. Lee, "Synthesis and characteristics of microcapsules containing electrophoretic particle suspensions", Springer-Verlag, 11 January 2006
• Tokiwa, Imamura, "Electrophoretic Mobility Studies of Colloidal Particles in Aqueous Solutions of Various Phosphates", Journal of the American Oil Chemists' Society, June 1969
• (1.23) T. Bert, H. De Smet, F. Beunis, K. Neyts, "Complete electrical and optical simulation of electronic paper", Science Direct, 13 October 2005
• (1.24) F. Strubbe, (K. Neyts), "Determination of the valency of pigment particles in electrophoretic ink", Ghent University, 30 November 2005
• M. Valentine, "Driver Electronics Morph for Flexible Displays", Power Electronics Technology, July 1, 2006

Good description of E-Ink displays and driver information

Colloidal suspension physics

• Poise and viscosity, units of viscosity

Greyscale properties

• 20.1: R.C. Liang, J. Hou, J. Chung, X. Wang, C. Pereira and Y. Chen, "Microcup® Active and Passive Matrix Electrophoretic Displays by Roll-to-Roll Manufacturing Processes", SID 03 DIGEST © 2003 SID

Reflective Cholesteric Displays (ChLCDs)

• List of papers on ChLCD from Kent Displays

Electro-wetting displays

• Hayes and Feenstra, "Video-speed electronic paper based on electrowetting", Nature 425, 383-385, 25 September 2003

Organic Light Emitting Diode (OLED)

• T. Shimoda, M. Kimura, S. Seki, H. Kobayashi, S. Kanbe, S. Miyashita, R. H. Friend, J. H. Burroughes, C. R. Towns, I.S. Millard, "Technology for active matrix light emitting polymer displays", Electron Devices Meeting, IEDM Technical Digest. International, pp. 107-110, December 1999

Display Power

• (1.1) W. Cheng, Y. Hou, M. Pedram, "Power Minimization in a Backlit TFT-LCD Display by Concurrent Brightness and Contrast Scaling", Design, Automation and Test in Europe Conference and Exhibition, Vol.: 1, pp. 252 - 257, 2004

LCD greyscale single pixel power consumption formula

• [10] LG Phillips, LP064V1 LCD specifications (640x480px, 0.9W-1.54W)
• [13](1.2) (13) H. Aoki, "Dynamic Characterization of a-Si TFT-LCD Pixels"
• (apparently related) Simrata, Subhasis, Gupta, Gate "Capacitance Characteristics of a Poly-Si Thin Film Transistor"

• (1.6) A. Iranli, W. Lee, M. Pedram, "Backlight Dimming in Power-Aware Mobile Displays", DAC, 2006
• (1.4) W. Cheng, C. Chao, "Minimization for LED-backlit TFT-LCDs", DAC, 2006

Addresses independant scaling of three color LED backlights based on image histogram

• (1.8) A. Iranli, M. Pedram, "DTM: Dynamic Tone Mapping for Backlight Scaling", DAC, June 2005
• (1.5) F. Gatti, A. Acquaviva, L. Benini, B. Ricco’, "Low Power Control Techniques For TFT LCD Displays", CASES, October 2002
• (1.3) L. Benini, R. Hodgson, P. Siegel, "System-level Power Estimation And Optimization", ISLPED, August 1998
• (1.7) L. Zhong, N. K. Jha, "Graphical User Interface Energy Characterization for Handheld Computers", CASES, October 2003

3.1: Whenever there is a screen change, the processor generates new data for the changing screen pixels and stores them into the framebuffer. This implies a higher energy consumption with increased temportal changes in the screen. Meanwhile, to maintain a screen on the LCD, the LCDC must sequentially read screen data from the frame-buffer and refresh the LCD pixels even when there is no screen change.

3.1: The display itself consists of several parts: LCD power circuitry, a front light, and an LCD. The LCDs used in the systems we studied are color active thin film transistor (TFT) LCDs. In such LCDs, each pixel has three comonents: R, G and B, signifying red, green and blue, respectively. Liquid crystals for each component are independently oriented by two polarizers, which are connected to a storage capacitor. The capacitor is in turn charged and discharged through a TFT to accommodate screen changes. Moreover, the capacitor must be refreshed at a high rate to maintain an appropriate voltage across the polarizers so that the corresponding liquid crystals remain properly oriented.

• (1.9) A. Kudurshian, "Techniques in Decreasing Power Consumption for Handheld Displays", CS IS: Issues in Embedded Systems, 2002
• (1.10) I. Choi, H. Shim, N. Chang, "Low-Power Color TFT LCD Display for Hand-Held Embedded Systems", International Symposium on Low Power Electronics and Design, August 12-14, 2002
• (1.11) B. W. Marks, "Power Consumption in Multiplexed Liquid-Crystal Displays", IEEE Transactions on Electron Devices, Vol. ED-29, No. 8, August 1982
• (1.25) B. W. Marks, "Power Reduction in Liquid-Crystal Display Modules", IEEE Transactions on Electron Devices, Vol. ED-29, No. 12, December 1982
• (1.16) T. N. Ruckmongathan, M. Govind, G. Deepak, "Reducing Power Consumption in Liquid-Crystal Displays", IEEE Transactions on Electron Devices, Vol. 53, No. 7, July 2006
• (1.18) W. F. Aerts, S. Verlaak, P. Heremans, "Design of an Organic Pixel Addressing Circuit for an Active-Matrix OLED Display", IEEE Transactions on Electron Devices, Vol. 49, No. 12, December 2002]
• Chung, Chen, Cheng, Yeh, "A Physically-Based Built-in Spice Poly-Si TF Model for Circuit Simulation and Reliability Evaluation", IEEE 1996
• Jagar, Cheng, Zhang, Wang, Poon, Kok, Chan, "A SPICE Model for Thin-Film Transistors Fabricated on Grain-Enhanced Polysilicon Film"
• NEC NL2432HC17-01B QVGA LCD for mobile applications with touch panel specification

Backlight power: 200mW

Panel and Driver power: 20mW

Active Matrix (Thin Film Transistor, TFT)

• Guo, Silva, "Circuit simulation of current-modulated field emission display pixel driver based on carbon nanotubes", Electronics Letters, September 2nd, 2004
• MOS16(2.0) poly-Si TFT model AIM-SPICE, HSPICE

Display Drivers

• Display Buffer Formats, MSDN Library
• Y. Nakajima, N. Goto, H. Kataoka, T. Maekawa, "A 3.8inch QVGA Reflective Color LCD with Integrated 3b DAC Driver", IEEE International Solid-State Circuits Conference, 2000
• Yongfu Zhu, Muju Li, Jianfeng Yuan, Chuanzhen Liu, Bailiang Yang, and Dezhen Shen, "Simulation of Pixel Voltage Error for a-Si TFT LCD Regarding the Change in LC Pixel Capacitance", IEEE Transactions on Electron Devices, Vol. 48, No. 2, February 2001

TFT characterization

• H.E.A. Huitema, G.H. Gelinck, J.B.P.H. van der Putten, K.E. Kuijk, C.M. Hart, E. Cantatore, D.M. de Leeuw, "Active-Matrix Displays Driven by Solution-Processed Polymeric Transistors", Advanced Materials Vol. 14 No. 17 pp. 1201-1204, August 29, 2002

LCD total pixel capacitance 5 pF

• R.C. Liang, J. Hou, J. Chung, X. Wang, C. Pereira and Y. Chen, "Microcup® Active and Passive Matrix Electrophoretic Displays by Roll-to-Roll Manufacturing Processes", SID Digest, 2003

Roll-to-Roll manufacturing

Grayscale through pulse-width modulation

Image Quality

• Universal Image Quality Index
• The Structureal Similarity (SSIM) Index for Image Quality Assessment
• MSU image quality software tool from Russian developer

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