A light source apparatus (8) includes a rear plate (80), a front plate
(89) formed with an anode layer (82), and a cathode (81) interposed
therebetween. The cathode includes a plurality of electrically conductive
carriers (812) and a plurality of field emitters (816) formed thereon.
The field emitters are uniformly distributed on anode-facing surfaces of
the conductive carriers. The anode layer includes a plurality of curving
portions (820) corresponding to the conductive carriers. Preferably, the
field emitters extend radially outwardly from the corresponding
conductive carriers. The conductive carriers are parallel with each
other, and are located substantially on a common plane. Each of the
conductive carriers can be connected with a pulling device arranged at
least one end thereof, and an example of the pulling device is a spring.
The conductive carriers may be cylindrical, prism-shaped or polyhedral.