Drive regulation and delay control in display systems

Claim 1

A system for operating a mulTiple position flat panel display device which comprises a base plate and face plate spaced apart and hermetically sealed together along a perimeter to form an envelope which is filled with an ionizable gas, a plurality of conductive runs on said base plate, and a plurality of groups of cathode segments on said base plate but insulated from said conductive runs, with each run being connected to one cathode segment in each group, each said group of cathode segments comprising a character position, and an anode electrode for each of said groups of cathode segments, said system comprising a power supply, a separate anode driver coupled to each of the anode electrodes for applying positive-going signals to the anode electrodes as each character position is energized, a separate cathode driver having its output coupled to each of said conductive runs for applying negative-going signals to selected ones of the cathode electrodes concurrent with energization of the associated anode electrode to display a character at each character position, a source of input signals coupled to each cathode driver, a first bus coupled between said power supply and through separate resistive paths to the output of each said cathode driver, a second bus connected to the input of each said cathode driver, a third bus coupled to a portion of each said cathode driver for maintaining bias potential thereon, an active circuit element coupled between said second and third buses for maintaining bias potential on said third bus, a capacitor connected between said first and second buses for receiving current from said active circuit element and storing charge, and then applying operating bias potential to each of the cathode drivers, and impedance means coupled between said capacitor and said active circuit element for charging the capacitor proportionally to the number of cathode segments energized in each said group at each character position to regulate the potential across it so that the firing threshold of the cathodes at the selected position in the device is exceeded and the cathodes exhibit cathode glow.

Claim 2

A system for operating a mulTiple position flat panel display device which comprises a base plate and face plate spaced apart and hermetically sealed together along a perimeter to form an envelope which is filled with an ionizable gas, a plurality of conductive runs on said base plate, and a plurality of groups of cathode segments on said base plate but insulated from said conductive runs, with each run being connected to one cathode segment in each group, each said group of cathode segments comprising a character position, and an anode electrode for each of said groups of cathode segments, said system comprising a power supply, a separate anode driver coupled to each of the anode electrodes for applying positive-going signals to the anode electrodes as each character position is energized, a separate cathode driver having its output coupled to each of said conductive runs for applying negative-going signals to selected ones of the cathode electrodes concurrent with energization of the associated anode electrode to display a character at each character position, a source of input signals coupled to each cathode driver, a first bus coupled between said power supply and through separate resistive paths to the output of each said cathode driver, a second bus connected to the input of each said cathode driver, a third bus coupled to a portion of each said cathode driver for maintaining bias potential thereon, an active circuit element coupled between said second and third buses for maintaining bias potential on said third bus, a capacitor connected between said first and second buses for receiving current from said active circuit element and storing charge, and then applying operating bias potential to each of the cathode drivers, and impedance means coupled between said capacitor and said active circuit element for charging the capacitor proportionally to the number of cathode segments energized in each said group at each character position to regulate the potential across it so that the firing threshold of the cathodes at the selected position in the device is exceeded and the cathodes exhibit cathode glow.

Claim 4

A system for operating a multiple position flat panel display device which comprises a base plate and face plate spaced apart and hermetically sealed together along a perimeter to form an envelope which is filled with an ionizable gas, a plurality of conductive runs on said base plate, and a plurality of groups of cathode segments on said base plate but insulated from said conductive runs, with each run being connected to one cathode segment in each group, each said group of cathode segments comprising a character position, and an anode electrode for each of said groups of cathode segments, said system comprising a power supply, a first bus extending from said power supply, a second bus, a third bus, and a fourth bus, a capacitor connected between said second and third buses, a first transistor connected between said third and fourth buses and having base, emitter, and collector electrodes, said first transistor and its associated circuitry sensing thE number of cathodes energized and to be turned on at any one character position and passing a charging current, proportional to said number of cathodes, to said capacitor, the charge developed therein being applied to said second bus and to said cathode runs and to the associated cathode segments, and a cathode driver circuit for each of said conductive runs and for each said one cathode segment in each said group of cathode segments, each said driver circuit including a source of input signals, and a second transistor having base, emitter, and collector electrodes, the emitter electrode being coupled both to said source of input signals and to said third bus, the base electrode being connected to said fourth bus, and the collector electrode being connected both to said second bus and to one of said conductive runs, whereby when a source of input signals is operated and applies a signal to the second transistor in the associated cathode drive circuit, said second transistor is driven to saturation before the associated cathode turns on and current flows through said first transistor to charge said capacitor proportionally to the number of cathodes to be turned on, said charge being applied as a generally negative potential to said second bus and to the associated cathodes to be turned on.

Claim 5

A system for operating a multiple position flat panel display device which comprises a base plate and face plate spaced apart and hermetically sealed together along a perimeter to form an envelope which is filled with an ionizable gas, a plurality of conductive runs on said base plate, and a plurality of groups of cathode segments on said base plate but insulated from said conductive runs, with each run being connected to one cathode segment in each group, each said group of cathode segments comprising a character position, and an anode electrode for each of said groups of cathode segments, said system comprising a power supply, a first bus extending from said power supply, a second bus, a third bus, and a fourth bus, a capacitor connected between said second and third buses, a first transistor connected between said third and fourth buses and having base, emitter, and collector electrodes, said first transistor and its associated circuitry sensing thE number of cathodes energized and to be turned on at any one character position and passing a charging current, proportional to said number of cathodes, to said capacitor, the charge developed therein being applied to said second bus and to said cathode runs and to the associated cathode segments, and a cathode driver circuit for each of said conductive runs and for each said one cathode segment in each said group of cathode segments, each said driver circuit including a source of input signals, and a second transistor having base, emitter, and collector electrodes, the emitter electrode being coupled both to said source of input signals and to said third bus, the base electrode being connected to said fourth bus, and the collector electrode being connected both to said second bus and to one of said conductive runs, whereby when a source of input signals is operated and applies a signal to the second transistor in the associated cathode drive circuit, said second transistor is driven to saturation before the associated cathode turns on and current flows through said first transistor to charge said capacitor proportionally to the number of cathodes to be turned on, said charge being applied as a generally negative potential to said second bus and to the associated cathodes to be turned on.