670 



DISPLAY SYSTEM DESIGN PROBLEMS 



40 80 120 160 200 240 280 320 350 

 VOLTS 



Fig. 12-45 Capacitive Characteristic of Ferroelectric Material. 



shown in our schematic varies the voltage drop across the electrolumines- 

 cent phosphor. The change in voltage across the light-producing element is 

 rapid with change in control potential, since we are basically dealing with a 

 capacitor-divider. The leakage resistance of this ELF (electroluminescence- 

 ferroelectric) circuit is extremely high, thereby retaining the voltage across 

 the light-producing phosphor for time durations of several minutes. We can 

 see in the ELF material the capabilities of fast time constant and storage 

 that are prerequisite to the ideal display device. 



Although the ferroelectric material has the advantage of good impedance 

 matching and fast time constant, much development must be done to 

 overcome the disadvantages of nonuniformity, temperature sensitivity, and 

 relatively high control voltage range. 



Horizontal Keying 

 Pulse Source 



Video 

 Signal 



Vertical Keying 

 Pulse Source 



Horizontal Keying 

 Pulse Distributer 



aaaa- 



E ] [] [] [ ] 



E ] [] [] [ ] 



E ] [] [] [ ] 

 E ] E] E] [ ] 



m m m ED 



Horizontal Actuated 

 Switch and Intermediate 

 Storage Capacitor 



Fig. 12-46 An Electronic Distribution System for ELF. 



