Patent ID: 7816851

Claim:
A planar light source device comprising: a lower substrate; a cathode electrode including at least two layers on the lower substrate, an uppermost layer of the cathode electrode including at least one selected from the group consisting of silver (Ag), lead (Pb), niobium (Nb), molybdenum (Mo), copper (Cu), tantalum (Ta), bismuth (Bi), aluminum (Al), titanium (Ti), and a molybdenum-tungsten (MoW) alloy; a gate electrode on the cathode electrode, the gate electrode being electrically insulated from the cathode electrode; a catalyst metal layer disposed on the gate electrode without any carbon nanotube grown on the gate electrode; a carbon nanotube grown on the cathode electrode and entirely separated from the lower substrate by the cathode electrode to form an emitter tip; and an upper substrate facing the lower substrate, the upper substrate including a fluorescent material and a transparent electrode.