Active plate
AssigneeKoninklijke Philips Electronics N. V.
InventorSteven C. Deane
Life of this patent
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Abstract
The storage capacitor of an active matrix liquid crystal display is formed to have a second electrode (28) that laterally overlaps a first electrode (10). The drain (30) of a thin film transistor extends across the gate electrode (2). The gate electrode (2) and the first electrode (10) of the storage capacitor are formed from a single metallization layer. The width of the gate electrode (2) and the first electrode (10) will tend to vary in parallel, as a result of process variation. This parallel variation tends to cancel out subsequent variation in the kick back voltage.
Claims10
An active plate, comprising:
- a substrate;
- a first metallisation layer defining gate electrodes and further defining first storage capacitor electrodes extending longitudinally across the substrate;
- a second metallisation layer defining source and drain electrodes and second storage capacitor electrodes;
- a semiconductor body layer forming thin film transistor bodies between the source and drain electrodes;
- and
- an insulation layer between first and second storage capacitor electrodes,
- wherein the drain electrode extends across the width of the gate electrode, and the second storage capacitor electrode overlaps the lateral edges of the first storage capacitor electrode.
A liquid crystal display comprising an active plate, a passive plate and liquid crystal between the active and passive plates, the active plate comprising a substrate;
- a first metallisation layer defining gate electrodes and further defining first storage capacitor electrodes extending longitudinally across the substrate;
- a second metallisation layer defining source and drain electrodes and second storage capacitor electrodes;
- a semiconductor body layer forming thin film transistor bodies between the source and drain electrodes;
- and
- an insulation layer between first and second storage capacitor electrodes,
- wherein the drain electrode extends across the width of the gate electrode, and the second storage capacitor electrode overlaps the lateral edges of the first storage capacitor electrode.
A method of manufacture of an active plate, comprising the steps of:
- depositing and patterning using a lower definition patterning process a first metallisation layer on a substrate, the first metallisation layer defining gate electrodes and first storage capacitor electrodes extending longitudinally across the substrate;
- depositing an insulation layer;
- depositing and patterning using a lower definition patterning process a semiconductor body layer forming thin film transistor bodies;
- and
- depositing and patterning using a higher definition process a second metallisation layer defining source and drain electrodes and second storage capacitor electrodes,
- wherein the second storage capacitor electrodes overlap the lateral edges of the first storage capacitor electrode.
Dependencies are inferred from the claim text.