| 摘要 |
<p>The invention relates to a field-emission electron source, comprising an electron-emitting tip (12-14), the greatest width of the cross-section of which is greater than 0.4 mm, wherein the outer surface of said tip is made of a composite material consisting of a matrix of an electrically insulating material, inside which and at the surface of which carbon particles are randomly distributed so as to render the tip electrically conductive. The carbon particles constitute less than 40 wt % of the composite material. The carbon particles are carbon-black particles having a specific surface area of more than 150 m2/g, or graphite-powder particles, and the tip is made entirely of said composite material.</p> |
