We propose to develop field emitter arrays with integrated focusing lenses that will enable flat-panel field-emission displays to achieve high resolution, high luminance, large dynamic range and high contrast, properties required for softcopy of digital x-ray imaging. The specific approaches are to develop the fabrication process for field emitter arrays with self-aligned integrated lenses and to experimentally demonstrate that the electron beam from these field-emitter arrays can be collimated such that the spot size on the phosphor screen can be dramatically improved. Field emission displays can have better visual qualities than cathode ray tubes, i.e., high resolution, isotropic modulation transfer function, high luminance, large dynamic range, high contrast and flickerless images, and at the same time retain wide viewing angle and good color of the CRT. In addition, field-emission displays are thin and flat. Electron beam collimation allows the application of high voltage phosphors and implementation of a larger gap between the field emitter arrays and the phosphor screen. High voltage phosphors are more efficient and have higher luminance and longer phosphor lifetime. They do not contaminate the field emitters. A larger gap provides better vacuum and thus improves field emitter lifetime. In Phase I we developed two processes to fabricate field-emitter arrays with self-aligned integrated lenses. The electron trajectory simulations indicate that the lenses are capable of providing good beam collimation. We believe that the proposed field-emitter arrays with the integrated lenses can improve not only resolution, but also image quality and reliability.
The flat-panel display market is steadily growing and is predicted to be worth $20-$30 billion per year by the year 2000. Field emission displays could capture a large portion of the market because of their better visual and performance characteristics relative to other flat panel displays. Field- emitter arrays with integrated lenses are also applicable for many electron gun applications.
