Electroluminescent display devices
First Claim
1. An active matrix electroluminescent display device comprising an array of pixels (10), each pixel comprising:
- an electroluminescent display element (20);
a drive transistor (22) for driving a current through the display element;
a storage capacitor (24) for storing a voltage to be used for addressing the drive transistor;
a discharge photosensitive element (34) for discharging the storage capacitor in dependence on the light output of the display element; and
a further photosensitive element (40) which is shielded from light emitted by the display element (20) while being exposed to light from other directions, and which is connected so as to cancel photocurrents produced in the discharge photosensitive element (34) by light from the other directions.
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Accused Products
Abstract
In an active matrix electroluminescent display device a storage capacitor (24) is provided in each pixel for storing a voltage to be used for addressing a drive transistor (22) which controls the illumination of the electroluminescent display element (20). A discharge photosensitive element (34) is provided for discharging the charge storage capacitor in dependence on the display element'"'"'s light output. A further photosensitive element (40) is provided so as to cancel photocurrents produced in the discharge photosensitive element (34) as a result of light input to the discharge photosensitive element other than from the pixel'"'"'s display element (20), the further photosensitive element being shielded (44) from light emitted by the display element while being exposed to light from other directions. Irregularities in the display output due to the effects of the unwanted light inputs to the discharge photosensitive elements are then avoided.
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Citations
13 Claims
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1. An active matrix electroluminescent display device comprising an array of pixels (10), each pixel comprising:
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an electroluminescent display element (20);
a drive transistor (22) for driving a current through the display element;
a storage capacitor (24) for storing a voltage to be used for addressing the drive transistor;
a discharge photosensitive element (34) for discharging the storage capacitor in dependence on the light output of the display element; and
a further photosensitive element (40) which is shielded from light emitted by the display element (20) while being exposed to light from other directions, and which is connected so as to cancel photocurrents produced in the discharge photosensitive element (34) by light from the other directions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification