Electron-emitting apparatus and method for emitting electrons

An electron-emitting apparatus comprising:

• an element having:
• an emitter section made of a dielectric material,
• a lower electrode disposed below the emitter section, and
• an upper electrode disposed above the emitter section to oppose the lower electrode, with the emitter section sandwiched therebetween, the upper electrode having a plurality of micro through holes and formed so that its surface around the circumference of the micro through holes facing the emitter section being apart from the emitter section,
• wherein the element supplies electrons to the emitter section from the upper electrode when an element voltage which is a potential of the upper electrode relative to a potential of the lower electrode, is a negative voltage whose absolute value is larger than a predetermined level to accumulate the electrons in the emitter section, and emits the electrons accumulated in the emitter section via the micro through holes when the element voltage is a positive voltage whose absolute value is larger than another predetermined level while the electrons are accumulated in the emitter section;
• and
• drive voltage applying means for applying a drive voltage between the upper electrode and the lower electrode to set the element voltage at the negative voltage and thereafter to set the element voltage at the positive voltage,
• wherein the drive voltage applying means increases the positive voltage stepwise.