US 6,011,274 AGranted

X-ray imager or LCD with bus lines overlapped by pixel electrodes and dual insulating layers therebetween

AssigneeOIS Optical Imaging Systems, Inc.

InventorsTieer Gu, Willem den Boer

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Abstract

This invention is related to an active matrix liquid crystal display (AMLCD) or an X-ray imaging device having a high aperture ratio. The imager or display has an increased aperture ratio because electrodes are formed over dual insulating layers so as to overlap portions of the array address lines and/or TFTs. Both the manufacturability and capacitive crosstalk of the device are improved due to the use of a photo-imageable organic insulating layer between the pixel electrodes and the address lines. An intermediate inorganic insulating layer is provided between the photo-imageable organic insulating layer and the overlapped TFTs in order to prevent the organic insulating layer from directly contacting semiconductor material in the TFTs thereby reducing potential voltage swings.

Claims19

Dependent claims

An X-ray imager comprising:

a substrate;
an array of thin film transistors (TFTs) disposed on said substrate, said array of TFTs including a plurality of address lines connected to said TFTs;
an array of electrodes disposed on said first substrate, a plurality of said electrodes in said array of electrodes overlapping at least one of said address lines;
an organic photo-imageable insulating layer including acrylic, said organic photo-imageable insulating layer having a dielectric constant .epsilon. less than about 4.0 disposed on said substrate between said address lines and said electrodes at least in areas of overlap and areas adjacent source electrodes of the TFTs;
an intermediate protective insulating layer disposed between said TFTs and said photo-imageable insulating layer so as to prevent said organic photo-imageable insulating layer from directly contacting semiconductor material in channels of said TFTs thereby reducing potential shifts of threshold voltage and sub-threshold swings in said TFTs;
and
said photo-imageable insulating layer and said intermediate protective layer each having a plurality of contact vias defined therein, wherein said electrodes are in electrical communication with corresponding TFT source electrodes through said contact vias defined in said insulating layers.

4 more elements

A liquid crystal display comprising:

a first substrate;
a liquid crystal layer;
an array of substantially transparent pixel electrodes on said first substrate for permitting image data to be displayed to a viewer;
a plurality of gate lines and TFT gate electrodes;
a semiconductor layer patterned so as to remain in an array of TFT areas;
a source and a drain electrode in each TFT area on said first substrate, a TFT channel being defined between the corresponding source and drain electrodes of each TFT, thereby forming an array of TFTs on said first substrate;
drain lines connected to said drain electrodes;
wherein a plurality of said pixel electrodes overlap at least one of a gate line and a drain line thereby increasing the pixel aperture ratio of the display;
a substantially transparent organic polymer photo-imageable insulating layer having a dielectric constant .epsilon. less than about 4.0, said photo-imageable insulating layer being disposed on said first substrate between (i) at least one of said pixel electrodes, and (ii) at least one of said TFTs and at least one of the overlapped lines, so as to insulate the pixel electrodes from at least one of said overlapped lines and at least one of said TFTs;
and
an intermediate insulating layer disposed between said photo-imageable insulating layer and said TFTs so as to prevent the photo-imageable insulating layer from directly contacting TFT portions which said photo-imageable insulating layer overlap.

8 more elements

Dependencies are inferred from the claim text.