Cold Cathode Gun Controllable at Low Voltages
Original Publication Date: 1978-Feb-01
Included in the Prior Art Database: 2005-Feb-20
A cheap, easily fabricated cold-cathode gun is useful for many electron-optical applications, and in particular is necessary for implementation of array types of cathode ray tubes (CRTs). Field-emission guns made by planar processing techniques are attractive for this purpose. However, prior methods of operation of planar processed guns have disadvantages. For example, it has been suggested that a close-packed array of needles be used as the cathode, with the anode spaced an appreciable distance away. This arrangement requires about a 5-kv anode potential in order to obtain a significant emission current. These large voltages are required because of undesirable interaction effects due to the presence of needles surrounding any given needle, thereby suppressing the field at the tip.