Emmett M. Howard

A full description of a simple and scalable fabrication process for electrowetting displays

Electrowetting displays provide a high white state reflectance of >50% and have attracted substantial world-wide interest, yet are primarily an industrially led effort with few details on preferred materials and fabrication processes. Reported herein is the first complete description of the electrowetting display fabrication process. The description includes materials selection, purification and all fabrication steps from substrate selection to sealing. Challenging materials and fabrication processes include dielectric optimization, fluoropolymer selection, hydrophilic grid patterning, liquid dosing, dye purification and liquid ionic content. The process described herein has produced pixel arrays that were switched at <15 V on active-matrix backplanes, and which have individual sub-pixel areas of <50 × 150 µm2. The majority of fabrication processes can conform to liquid-crystal style manufacturing equipment, and therefore can be readily adopted by many display practitioners. Also presented are additional tips and techniques, such as controlling the onset of oil film break-up in an electrowetting display. This paper should enable anyone skilled in displays or microfabrication to quickly and successfully set up research and fabrication of electrowetting displays.

Nano‐emissive display technology for large‐area HDTV

— Using nano-emissive display (NED) technology, Motorola labs has successfully developed 5-in. full-color display prototypes. Carbon-nanotube-based field-emission displays with a pixel size of 0.726 mm for a 42-in. HDTV exhibit video image quality comparable to CRT displays and demonstrate a luminance of 350 cd/m2. These novel low-drive-voltage NEDs take advantage of selective growth of CNTs to obtain the desired electron-emission performance while maintaining inexpensive manufacturing due to a simple self-focusing and self-regulating planar structure. Improved video image quality and color purity are achieved with very low power consumption and without the need for an expensive focusing grid.

63.2: High Brightness, High Voltage Color Field Emission Display Technology

We have designed nanotube-based field emission displays to operate above 6500 V. As a result, we have improved the white-screen luminance of HDTV resolution (0.726 mm pixel) field emission displays beyond 700 cd/m2. We have maintained good color purity without employing separate focusing electrodes. In addition, we demonstrate spacers operating beyond 10,000 volts on the anode without any charging that would distort the image.

Dynamic studies on the charging of spacers for high-voltage field-emission displays

— In this article, a systematic study on the relationship between the rate of spacer surface-charge accumulation and the anode voltages in a dynamic setting is presented. The spacers are placed in a test package simulating a field-emission panel where electron trajectories are recorded along a preset timeline. True secondary emission of spacers under the influence of an anode field is then deduced and the factors affecting the rate of charge accumulation on the spacer surface are discussed. The results of invisible spacers under different operating conditions of anode voltage, emission current, and pulse width will also be given.

51.4: Development of Flexible Electrowetting Displays for Stacked Color

Electrowetting displays show promise for realizing vividly colorful electronic paper using stacked color layers to obtain high reflectivity. We develop and demonstrate technologies needed to realize stacked displays including (1) strategies for controlling colorant location, (2) incorporating spacers, black surround, and thin seals, and (3) building working modules on flexible substrates.

A carbon-nanotube field-emission display with simple electron-beam trajectory control

— A unique gated cathode structure for a carbon-nanotube-based field-emission display has been designed and built. This structure optimizes the electron-beam profiles to assure a good color gamut and high anode efficiency without requiring specific focusing electrodes or structure. A computer simulation, written to analyze and improve the device design, shows good correlation with the experimental data and helps predict design margins. A full-color frit-sealed display built with this approach demonstrates an excellent color gamut of the phosphor, and the model predicts avenues for further color-gamut improvements.

37.3: A Carbon Nanotube Field Emission Display with Simple Electron Beam Trajectory Control

A unique gated cathode structure for a Carbon Nanotube-based field emission display has been designed and built. This structure optimizes the electron beam profiles so as to assure high anode electron efficiency and a good color gamut without requiring specific focusing electrodes or structure. A computer simulation written to analyze and aid with the design shows good correlation with the experimental data and also helps to predict design margins. A full color frit-sealed display built with the approach demonstrates an excellent color gamut of the phosphor, and the model predicts avenues for increasing the color gamut further.