US 2012/0056185 A1 · LIQUID CRYSTAL DISPLAY DEVICE

Abstract

In an IPS type liquid crystal display device having a reduced number of layers and formed through a reduced number of photolithography steps, an off current of a TFT is prevented from increasing due to photocurrent. A drain line, a TFT drain electrode, and a source electrode each have a multilayer structure including metal and a semiconductor layer. The drain line and the semiconductor layer formed thereunder are separated from the drain electrode and the semiconductor layer formed thereunder with the drain line and the drain electrode connected by a blocking conductive film formed of ITO of which the pixel electrode is also formed. Photocurrent generated by backlight is blocked by the blocking conductive film without flowing into the TFT. Therefore, the number of photomasks required in the production process can be decreased without an increase of causing the off current of the TFT.

Claims6

Dependent claims

A liquid crystal display device including a TFT substrate, a counter substrate, and liquid crystal held between the TFT substrate and the counter substrate,

wherein the TFT substrate has a gate electrode, a gate insulating film, and a semiconductor layer formed thereon in the cited order, the semiconductor layer having a drain electrode, a drain line, and a source electrode formed thereon except where a TFT channel region is formed;
the gate insulating film has a rectangular pixel electrode of ITO formed thereon, the pixel electrode being overlappingly connected with the source electrode;
the pixel electrode has a comb-teeth-shaped common electrode disposed thereon across an insulating film;
and
the drain electrode and the semiconductor layer thereunder are separated from the drain line and the semiconductor layer thereunder, the drain electrode and the drain line being connected by a blocking conductive film formed of the same material as the pixel electrode.

2 more elements

Dependencies are inferred from the claim text.

Liquid crystal display device

Life of this patent

Liquid crystal display device

Life of this patent

Abstract

Claims6