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Electrofluidic Imaging Films for Simultaneous Advancements in Performance and Simplicity for Electronic Paper

Hagedon, Matthew A
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378109126

Abstract Details

2013, PhD, University of Cincinnati, Engineering and Applied Science: Electrical Engineering.
As technology has developed and become pervasive, more and more daily activities occur through interaction with electronic displays. More than 40 years of development have resulted in emmisive liquid crystal displays (LCD) and organic light emitting displays (OLED) which not only create extremely sharp, vibrant images but also are thin and portable, however emissive displays suffer from large power drains and low readability in high ambient light conditions. Reflective displays solve these two problems by reflecting ambient light thereby reducing the need for a back light in most reading conditions. Though LCD was used for many years in reflective display applications, however liquid crystal light valves are not ideal for reflective displays due to the heavy light loss which occurs in the polarization layers. The reflectance levels of these displays were too low to be referred to as an electronic paper (e-Paper). Electrophoretic Displays (EPD), commercialized by Eink, combine high reflectivity, paper like reflection, and zero-voltage stability to create the first commercial technology which was assigned the term e-Paper. Improvements to the Eink product have placed it as the dominant display technology in e-readers today. However, with a 40% reflectance efficiency and >100ms switching times, Eink cannot achieve full color reflectance or video speed operation leaving a lot of room for improvement in the e-Paper space, yet no technology to date has been successfully commercialized which can compete with Eink. To do so, a technology must not only offer significantly increased performance, but it must also be manufactured at a competitive cost point and ideally provide zero-power stability for extreme low-power operation. This dissertation introduces a technology which is referred to as the electrofluidic imaging film which specifically targets increased performance to enable the next generation of reflective e-Paper displays with color and video speed operation while retaining the unique advantages of the Eink EPD display. The new display architecture utilizes the principals developed by previous electrofluidic displays to achieve high performance but utilizes a novel configuration to enable zero-voltage stability and a non-aligned fabrication without a need for pixel walls. First the requirements for the optics of an e-Paper display are discussed. This develops the understanding of the optical problems which must be overcome when making an efficient reflective display which has a paper like appearance. Then the EFD imaging film is demonstrated and the structure and operating principals are reviewed. We demonstrate a >70% white state reflectance and a >15ms switching time at a resolution of 150 pixels per inch. A novel fabrication technique is then demonstrated for the key display components, the fluid transfer membrane. The process integrates an engineered gain diffuser into the film creating a highly paper like reflectance profile using principals developed earlier in the dissertation. Finally, a predictive model is developed which demonstrates the dominant microfluidic phenomena that are involved in the display switching.
Jason Heikenfeld, Ph.D. (Committee Chair)
Jeffrey P. Maranchi, Ph.D. (Committee Member)
Chong Ahn, Ph.D. (Committee Member)
Ian Papautsky, Ph.D. (Committee Member)
Andrew Steckl, Ph.D. (Committee Member)
175 p.
Electrical Engineering
e-Paper; Displays; Optics; Microfluidics; Electrofluidics

Recommended Citations

Citations

  • Hagedon, M. A. (2013). Electrofluidic Imaging Films for Simultaneous Advancements in Performance and Simplicity for Electronic Paper [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378109126

    APA Style (7th edition)

  • Hagedon, Matthew. Electrofluidic Imaging Films for Simultaneous Advancements in Performance and Simplicity for Electronic Paper. 2013. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378109126.

    MLA Style (8th edition)

  • Hagedon, Matthew. "Electrofluidic Imaging Films for Simultaneous Advancements in Performance and Simplicity for Electronic Paper." Doctoral dissertation, University of Cincinnati, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378109126

    Chicago Manual of Style (17th edition)

ucin1378109126
663
© 2013, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.