Disadvantages
Just like any other displays with individually addressable sub-pixels, FED displays can potentially suffer from manufacturing problems that will result in dead pixels. However, the emitters are so small that many "guns" can power a sub-pixel, the screen can be examined for dead emitters and brightness corrected by increasing the pulse width to make up for the loss through increased emissions from the other emitters feeding the same pixel
The efficiency of the field emitters is based on the extremely small radii of the tips, but this small size renders the cathodes susceptible to damage by ion impact. The ions are produced by the high voltages interacting with residual gas molecules inside the device.
FED display requires a vacuum to operate, so the display tube has to be sealed and mechanically robust. However, since the distance between the emitters and phosphors is quite small, generally a few millimeters, the screen can be mechanically reinforced by placing spacer strips or posts between the front and back face of the tube.
FEDs require high vacuum levels which are difficult to attain: the vacuum suitable for conventional CRTs and vacuum tubes is not sufficient for long term FED operation. Intense electron bombardment of the phosphor layer will also release gas during use.
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