James E. Jaskie

Field emission displays: a critical review

Abstract The goal of making attractive flat panel displays (FPDs) based on arrays of cold cathodes has now become a reality. Pixtech and Futaba have begun commercial production of low voltage, monochrome field emission displays (FEDs). Moreover, public response to the high voltage, full color, VGA FED prototypes shown by Candescent and Motorola at various technical meetings and exhibits has been extremely positive and encouraging. Yet, the future of the FED industry is uncertain. The tremendous improvements in visual quality and reduction in manufacturing cost of liquid crystal displays, as well as the formidable progress made in other FPD technologies has raised the standard for FEDs. In this article, we first review the status of FEDs based on the Spindt microtip emitter. We focus on the scalability of the Spindt process to large substrates, phosphor selection, high voltage stability, and display lifetime. Second, we discuss in detail the recent advances made in alternate cold cathode technology, including carbon nanotubes and composite materials, and their potential advantages for FPD. This new technology offers a tremendous opportunity to lower capital investment, to cut manufacturing costs and to challenge the existing flat panel industry.

Towards a low-cost high-quality carbon-nanotube field-emission display

We have developed field-emission-display technology driven by chemical-vapor-deposition-grown carbon-nanotube emitters incorporated in a simple, low-cost device structure. Here, we report on frit-sealed test displays with a brightness of 3000 cd/m 2 at 3 kV and a lifetime of 9000 hours with only 45% degradation. We also demonstrate the scalability of the technology with a uniform high-brightness 6-in. QVGA that displays video images with a switching voltage of 40 V.

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.

19.1: Distinguished Paper: Towards A Low Cost High Quality Carbon Nanotubes Field Emission Display

We have developed field emission display technology driven by Chemical Vapor Deposition grown carbon nanotube emitters incorporated in a simple, low cost device structure. Here we report in frit-sealed test vehicles 3000Cd/m2 brightness at 3kV, a lifetime of 7500 hours with only 40% degradation. We also demonstrate the scalability of the technology with a uniform, high brightness, 6″ QVGA cathode array showing video images with a switching voltage of ∼ 50 V.

Development of Field Emission Flat Panel Displays at Motorola

Over the past few years, Motorola, as well as several other companies around the world, have been developing a new type of flat panel display, called the field emission display (FED). The FED combines many of the advantages of its cousin, the cathode ray tube (CRT), including high brightness and contrast, wide angle viewability, and speed in a flat package that is only a few millimeters thick. A 14 cm diagonal FED prototype built at Motorola Flat Panel Display Division is shown below, in Figure 1.

Motorola Spindt tip FEDs operating for 10,000 hours

At Motorola, full-color, Spindt tip field emission displays (FEDs) have now been running continuously for more than 10,000 hours on our life test racks. These displays demonstrate that adequate FED lifetime can be achieved using Spindt tip technology, color phosphors, and high anode voltage (4 kV). Motorolas spacer technology also remains invisible after 10,000 hours. We discuss these results and the dependence of lifetime on important variables.

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.