| 摘要 |
<p>PURPOSE: To improve electron emission efficiency. CONSTITUTION: The principal part of an electron emission source is constituted by coating a cathode electrode 13 with an insulating layer 15 and a gate electrode 14 in order, and forming a very small hole 20 through the gate electrode 14 and the insulating layer 15. The thickness t1 of the insulating layer 15 is less than 1μm, for example, 0.3μm. The top of the cathode electrode 13 is flat, and the section 13A exposed with the very small hole 20 functions as an electron emission face. When voltage is impressed between both electrodes, an equipotential level surface Em is made in roughly parallel with the electron emission face 13A on this face. Since electrons e shifts in the vertical direction to this equipotential level, a great part of electrons e are emitted through the very small hole 20, and because the electron emission face 13A is flat, the quantity of emitted electrons becomes large.</p> |
