Active matrix display device
AssigneeTPO Hong Kong Holding Limited
InventorsJason R. Hector, Martinus P. Creusen
Life of this patent
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Abstract
A display device comprising an array of pixels, with gates of thin film transistors of the pixels in a row connected to a row conductor. Row driver circuitry provides row address signals for controlling the switching of the transistors of the pixels of the row including an ON gate voltage and an OFF gate voltage. Control circuitry shifts the ON gate voltage and the OFF gate voltage in dependence on drive and/or environmental conditions such as temperature and/or refresh rate. The control circuitry maintains a constant difference between the ON gate voltage and the OFF gate voltage. This allows the gap between the on and off voltages to be reduced, which results in power savings. The kickback voltage is kept constant so that kickback compensation is kept simple.
Claims19
A display device comprising an array of pixels, each pixel comprising a thin film transistor switching device (14) and a display element (16), the array being arranged in rows and columns, wherein each row of pixels shares a row conductor (10), which connects to the gates (14a) of the thin film transistors (14) of the pixels in the row, wherein row driver circuitry (30) provides row address signals for controlling the switching of the transistors (14) of the pixels of the row, wherein the row address signals each comprise a waveform (42, 44) for providing an ON gate voltage and an OFF gate voltage to the drive transistor (14), wherein the device further comprises control circuitry (50) for shifting the amplitudes of the ON gate voltage and the OFF gate voltage in dependence on drive and/or environmental conditions, the control circuitry (50) maintaining a constant amplitude difference (39) between the ON gate voltage and the OFF gate voltage.
A row driver circuit for an active matrix display device for providing row address signals, in which device each pixel comprises a thin film transistor (14) switching device and a display element (16), and the row address signals are provided to the gates (14a) of the thin film transistors (14) of the pixels in the row, wherein row driver circuit comprises:
- means (30) for providing row address signals comprising a waveform for providing an ON gate voltage and an OFF gate voltage to the drive transistor,
- an input for receiving a control signal (52) dependent on drive and/or environmental conditions;
- and
- means (50) for shifting the amplitude of the ON gate voltage and the OFF gate voltage in response to the control signal (52), and maintaining a constant amplitude difference between the ON gate voltage and the OFF gate voltage.
A method of generating row address signals for an active matrix display device, the method comprising:
- providing row address signals (42, 44) comprising a waveform for providing an ON gate voltage and an OFF gate voltage to the drive transistors (14) of the pixels in a row, and
- shifting the amplitude of the ON gate voltage and the OFF gate voltage in dependence on drive and/or environmental conditions whilst maintaining a constant amplitude difference between the ON gate voltage and the OFF gate voltage.
Dependencies are inferred from the claim text.