Matrix display devices with redundant driving transistor arrangement for improved fault tolerance
First Claim
1. A matrix display device comprising a plurality of display elements arranged in an array, each of which comprises electrodes carried on opposing substrates with electro-optical material therebetween and is associated with switching means operable to control the application of data signals to the display element in response to switching signals being applied thereto, characterised in that the switching means associated with each display element comprises a fault tolerant switching circuit having two branches connected electrically in parallel between a common data signal input and an electrode of the display element, with each branch comprising a plurality of transistors whose main current carrying electrodes are connected in series between the common data signal input and the picture element electrode and with the control electrodes of the transistors of both branches being connected to a common switching signal input.
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Accused Products
Abstract
In a matrix display device, such as an LCD-TV, supply of data signals to each one of an array of display elements is controlled by respective switching devices circuits in response to applied switching signals. Each switching device circuit is fault-tolerant and has two branches each containing two series-connected transistors, e.g. TFTs, and connected in parallel between a data signal input and a display element electrode with the transistor gates being connected to a common switching signal input. For commonly-occuring transistor defects such a circuit can tolerate a defective transistor, thereby improving fabrication yields. Further transistor defects are accommodated for improved fault tolerance by provision of impedances (38) in the gate supply lines. The impedance may be resistors or active loads (41).
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13 Claims
- 1. A matrix display device comprising a plurality of display elements arranged in an array, each of which comprises electrodes carried on opposing substrates with electro-optical material therebetween and is associated with switching means operable to control the application of data signals to the display element in response to switching signals being applied thereto, characterised in that the switching means associated with each display element comprises a fault tolerant switching circuit having two branches connected electrically in parallel between a common data signal input and an electrode of the display element, with each branch comprising a plurality of transistors whose main current carrying electrodes are connected in series between the common data signal input and the picture element electrode and with the control electrodes of the transistors of both branches being connected to a common switching signal input.
Specification