ELECTRON EMITTING ELEMENT, ELECTRON SOURCE, AND IMAGE FORMING DEVICE

• Main Authors: TSUKAMOTO TAKEO, YAMANOBE MASATO
• Format: Patent
• Language: English
• Published: 22.12.1997
• Edition: 6
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRICITY

PROBLEM TO BE SOLVED: To control an emission current with high accuracy at a high speed by providing the third electrode across an insulating layer on the substrate side of an electron emission section, and controlling the potential applied to this electrode. SOLUTION: An electron emission section 5 is constituted with high-resistance cracks formed on a part of a conductive film 4, a voltage is applied between element electrodes 2, 3 to emit electrons from the electron emission section 5. A conductive layer is set to a high potential by a high-voltage power supply, and the parallel electric field is formed across vacuum between an electron emitting element and a glass substrate 8. When a positive potential is applied to the third electrode 6, the emission current quantity is increased, and the electron emission efficiency is improved. When a negative potential is applied to the third electrode 6, the emission current quantity is decreased. When the thickness of an insulating layer 7 is set within the five times the thickness multiplied with the crack width in the electron emission section 5 by the relative dielectric constant of the insulating layer 7, the emission current quantity can be controlled with very small electric power.