ADJUSTABLE GRAY LEVEL FED CONTROLLED BY ACTIVE MATRIX CURRENT SOURCE

PROBLEM TO BE SOLVED: To provide an adjustable gray level FED controlled by an active matrix current source. SOLUTION: According to the FED of this invention, the FED driven by a low control voltage active current source is formed by converting a voltage control signal into an output current by using an active device, and recording and maintaining the voltage control signal with a capacitor, and a gray level and brightness can be adjusted and maintained. The brightness is held constant by the active device and the capacitor, and thereby the FED achieves high momentary brightness under the low voltage and low brightness and generates high average brightness, and a problem of arc current occurring when applying high voltage is solved. Further, since the current flowing through the FED is controlled by the current source, a large arc current generated due to a vacuum state is suppressed by a constant current source so as to be maintained at a constant value, and the arc current is prevented from being generated, and the yield is improved. COPYRIGHT: (C)2004,JPO