Patent ID: 7336042
Filing Date: 2008-02-26
Classification: G09G

Abstract:
1. A display apparatus comprising: a field emission device including a first electrode serving as a display plate on which phosphor material is coated, and a second and a third electrode for emitting electrons to be ejected onto the first electrode, wherein the phosphor material emits light when the electrons are ejected thereonto; a voltage application unit for applying driving voltages to the second and the third electrode to control an emitted amount of the electrons in accordance with display data and allow a specific part of the phosphor material to emit light; and a brightness control unit for controlling an emission brightness of the phosphor material, wherein the brightness control unit includes: a first electrode current detection unit for detecting a signal corresponding to a current flowing through the first electrode over a specific period of time; a display data amount estimation unit for detecting a signal corresponding to the display data inputted to the second electrode over the specific period of time; a comparing unit for generating an error signal representing a difference between the signal corresponding to the current flowing through the first electrode and the signal corresponding to the display data; a preset value generation unit for generating a preset value; an average turn-on rate detection unit for calculating an average turn-on rate indicating a degree to which the phosphor material emits light over the specific period of time; an average turn-on rate analysis unit for finding whether the average turn-on rate is greater than, equal to or smaller than a threshold value; and a selection unit for making the third electrode driven by a feedback control system in accordance with the error signal if the average turn-on rate is found to be greater than or equal to the preset value, and by the preset value if the average turn-on rate is found to be smaller than the preset value.