Low-loss sinusoidal drive system and technique
First Claim
1. A method for driving thin-film electroluminescent displays comprising:
- generating an alternating signal and providing an output thereof;
coupling said alternating signal output to an inductance-capacitance resonant tank circuit to produce and maintain a resonant sinusoidal output;
coupling said resonant sinusoidal output to the backplane electrode of a thin-film electroluminescent display having a backplane electrode and a plurality of segment electrodes by coupling said electroluminescent display in electrical parallel with the capacitance of said resonant tank circuit; and
controlling each of said plurality of segments to selectively produce a luminous display.
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Accused Products
Abstract
A low-loss sinusoidal drive system is disclosed for powering thin-film electroluminescent displays (TFEL). A DC power source coupled through a DC-to-AC inverter and driving an LC resonant tank circuit is used to produce a sinusoidal supply voltage. The sinusoidal supply voltage is coupled to produce a sinusoidal backplane driving voltage and coupled to a synchronizer circuit which controls drive logic for selectively energizing segments of the TFEL display. The drive logic is coupled to respond to an on-off command for selecting a particular segment such that the average DC voltage across a segment of the TFEL is zero, independent of the on/off condition of the segment. The backplane sinusoidal voltage may be applied in common to multiple TFEL devices with the synchronizing and drive logic circuits individually selecting the segments for TFEL drive.
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Citations
14 Claims
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1. A method for driving thin-film electroluminescent displays comprising:
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generating an alternating signal and providing an output thereof; coupling said alternating signal output to an inductance-capacitance resonant tank circuit to produce and maintain a resonant sinusoidal output; coupling said resonant sinusoidal output to the backplane electrode of a thin-film electroluminescent display having a backplane electrode and a plurality of segment electrodes by coupling said electroluminescent display in electrical parallel with the capacitance of said resonant tank circuit; and controlling each of said plurality of segments to selectively produce a luminous display.
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2. A power supply and drive system for a display comprising:
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a display element having a common backplane electrode and a plurality of individual segment eletrodes; means for producing and maintaining a resonating sinusoidal output signal from an inductance-capacitance resonant tank circuit and coupling said output signal to said backplane electrode by coupling said display element in electrical parallel with the capacitance of said tank circuit; and means for applying control signals to selected ones of said plurality of segment electrodes for causing said selected segment electrodes to become luminous. - View Dependent Claims (3, 4, 5, 6)
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7. A thin-film electroluminescent display system comprising:
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a thin-film electroluminescent display having a backplane electrode and a plurality of segment electrodes which may be selectively controlled to form a luminous display; a DC-AC inverter for providing an alternating signal output; an inductance-capacitance tank circuit coupled to receive the alternating signal output of said DC-AC inverter and produce a resonant sinusoidal output; means responsive to said resonant sinusoidal output for controlling said DC-AC inverter to maintain resonance of said resonant sinusoidal output, said resonant sinusoidal output being coupled to said backplane electrode by coupling said electroluminescent display in electrical parallel with the capacitance of said tank circuit; and means for selectively controlling the plurality of segment electrodes for producing a luminous display. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A power supply and drive system for a display comprising:
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a display element having a common backplane electrode and a plurality of individual segment electrodes; means for producing and maintaining a resonating sinusoidal output signal from an inductance-capacitance resonant tank circuit and coupling said output signal to said backplane electrode; and means for applying control signals to selected ones of said plurality of segment electrodes to cause said selected segment electrodes to become luminous, said means for applying control signals comprising means for causing an alternating signal across the selected segment eletrode to produce illumination so that there is no DC offset signal applied to the display element.
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14. A thin-film electroluminescent display system comprising:
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a thin-film electroluminescent display having a backplane electrode and a plurality of segment electrodes which may be selectively controlled to form a luminous display; a DC-AC inverter for providing an alternating signal output; an inductance-capacitance tank circuit coupled to receive the alternating signal output of said DC-AC inverter and produce a resonant sinusoidal output; means responsive to said resonant sinusoidal output for controlling said DC-AC inverter to maintain resonance of said resonant sinusoidal output, said resonant sinusoidal output being coupled to said backplane electrode; and means for selectively controlling the plurality of segment electrodes to produce a luminous display by driving said segment electrodes so that there is a zero net DC offset signal between the segment electrodes and backplane electrode at all times.
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Specification