Improvement of cathode life of pierce gun using for the deposition of MgO protection layer in plasma display

To improve the cathode life of pierce gun of evaporator used for deposition of MgO thin film as a protection layer in ac-PDPs, various operation conditions of pierce gun including vacuum pressure, deposition beam current and the erosion depth of cathode resulted from ion bombardment were studied. According to the experimental results, higher pressure and higher beam current results in a shorter cathode life. In addition, by reducing the spot size and deposition beam current through a modified focus lens of pierce gun system, a longer cathode life can be achieved.