Patent ID: 6377002
Filing Date: 2002-04-23
Classification: H01J

Abstract:
A cathodoluminescent visual display device having a plurality of pixel dots for displaying images when said device is viewed in a viewing direction, comprising:a housing defining a chamber therein, said housing having a face plate, and a back plate; an anode on or near said face plate; luminescent means that emits light in response to electrons, and that is on or adjacent to the anode; a plurality of rows of field emission cathode elements in the chamber between the face and back plates, said elements comprising base and gate electrodes, wherein at least one row of the elements includes more than one element; a first spacer structure defining holes therein for passage of electrons; a first set of elongated grid electrodes between the anode and cathode, said grid electrodes being transverse to the rows of cathode field emission elements, the electrodes overlapping the luminescent means and said rows at locations when viewed in the viewing direction, wherein the overlapping locations define rows and columns of pixel dots; and a circuit applying electrical potentials to the anode, cathode, the set of grid electrodes and the elements in the rows of field emission cathode elements, causing the cathode elements to emit electrons and such electrons to travel to the luminescent means at desired pixel dots on or adjacent to the anode for displaying images of desired brightness, said circuit applying electrical potentials to the rows of cathode field emission elements to control scanning or brightness of the display; wherein each of said field emission cathode elements comprises: a base electrode; a gate electrode electrically insulated from the base electrode; a plurality of microtip structures; a first set of resistors, each resistor in the first set electrically connected to a corresponding structure; and a current limiting circuit connected to the resistors having a constant current source so that the resistors and the circuit connect the base electrode to the microtip structures to limit total amount of current delivered by the base electrode to said plurality of microtip structures.