Thin film EL display panel drive circuit

Claim 1

A drive circuit for a thin film electroluminescent (EL) display panel having a plurality of scanning electrodes extending in one direction, a plurality of data electrodes extending in a second direction orthogonal to said first direction, and an EL layer sandwiched therebetween, picture elements being defined by intersections of said scanning and data electrodes, said picture elements being controllably selected to cause luminescence thereof, the circuit comprising: first switching circuit means connected to each of said scanning electrodes for applying a scanning voltage of negative polarity thereto; second switching circuit means connected to each of said scanning electrodes for applying a scanning voltage of positive polarity thereto; data electrode driver means connected to said data electrodes for selectively applying a modulation voltage or ground voltage to each said data electrode; said scanning electrodes being grouped into odd numbered scanning electrodes and even numbered scanning electrodes and being scanned in two fields in which odd numbered scanning electrodes are provided with said negative polarity voltage and even numbered scanning electrodes are provided with said positive polarity voltage in a first field, said negative and positive polarity voltage being applied to said even and odd numbered scanning electrodes, respectively, in a second field; said data electrode driver means including means for applying said modulation voltage to data electrodes defining selected picture elements along intersecting selected odd numbered scanning electrodes in said first field, applying ground to data electrodes defining selected picture elements along intersecting selected even numbered scanning electrodes in said first field, applying ground to data electrodes defining selected picture elements along intersecting selected odd numbered scanning electrodes in said second field, applying said modulation voltage to data electrodes defining selected picture elements along intersecting selected even numbered scanning electrodes in said second field, and applying voltage levels to data electrodes defining non-selected picture elements along intersecting selected scanning electrodes in each field of a different voltage to that applied to data electrodes defining selected picture elements intersecting selected scanning electrodes to inhibit selection of said non-selected picture elements.

Claim 9

A method of driving an electroluminescent display panel including an electroluminescent layer disposed between a group of scanning electrodes and a group of data electrodes, said scanning electrodes being arranged in alternating odd and even groups, comprising: (a) applying a first voltage pulse of a first polarity having sufficient voltage to cause electroluminescence to selected pixels of an odd scanning line; (b) applying a second voltage pulse of a second polarity also having sufficient voltage to cause electroluminescence to selected pixels of an even scanning line adjacent said odd scanning line; repeating said steps (a) and (b) to successive odd and even scanning lines until said first and second voltage pulses have been applied to all said scanning electrodes; (c) applying said second voltage pulse to selected pixels of an odd scanning line; (d) applying said first scan voltage pulse to selected pixels of an even scanning line adjacent said odd scanning line; repeating said steps (c) and (d) to successive odd and even scanning lines until said first and second voltage pulses have been applied to all said scanning electrodes; said first and second voltage pulses supplied to each said scan line in steps (a) and (b) having a constant phase difference from the first and second voltage pulses supplied therein during said steps (c) and (d) on each said scan line; said first and second voltage pulses in said steps (a-d) being formed from the simultaneous application of said scan pulses on a selected said scanning line and a modulation waveform on each said data line, the sum of each said scan pulse and said modulation waveform on pixels extending along a non-selected said data line being insufficient to cause electroluminescence.

Claim 10

A method of driving an electroluminescent display panel including an electroluminescent layer disposed between a group of scanning electrodes and a group of data electrodes, said scanning electrodes being arranged in alternating odd and even groups, comprising: (a) applying a first voltage pulse of a first polarity having sufficient voltage to cause electroluminescence to selected pixels of an odd scanning line; (b) applying a second voltage pulse of a second polarity also having sufficient voltage to cause electroluminescence to selected pixels of an even scanning line adjacent said odd scanning line; repeating said steps (a) and (b) to successive odd and even scanning lines until said first and second voltage pulses have been applied to all said scanning electrodes; (c) applying said second voltage pulse to selected pixels of an odd scanning line; (d) applying said first scan voltage pulse to selected pixels of an even scanning line adjacent said odd scanning line; repeating said steps (c) and (d) to successive odd and even scanning lines until said first and second voltage pulses have been applied to all said scanning electrodes; said first and second voltage pulses supplied to each said scan line in steps (a) and (b) having a constant phase difference from the first and second voltage pulses supplied therein during said steps (c) and (d) on each said scan line; said first and second voltage pulses in said steps (a-d) being formed from the simultaneous application of said scan pulses on a selected said scanning line and a modulation waveform on each said data line, the sum of each said scan pulse and said modulation waveform on pixels extending along a non-selected said data line being insufficient to cause electroluminescence.