Liquid crystal display device and method of manufacturing the same

Abstract

In a liquid crystal display device comprising a first substrate 101 having a color filter, a second substrate 131 and a liquid crystal layer disposed therebetween, a color filter layer 110 is disposed on a protection film 108 of a thin film transistor formed on the first substrate 101 so as to be partitioned by a light shielding portion 111, and a common electrode 103 is disposed thereon. A pixel electrode to be connected to a source electrode 107 is disposed through a through hole formed in an overcoat layer (interlayer separation film) 112. On the first substrate below the color filter layer 110 are provided plural scan signal electrodes, plural video signal electrodes crossing the scan signal electrodes in a matrix form, plural thin film transistors formed in association with the crossing points between the electrodes. Each pixel is provided with a common electrode 103 which is connected over plural pixels through a common electrode wire to supply reference potential, and a pixel electrode 114 which is connected to the corresponding thin film transistor and disposed so as to confront the common electrode in the pixel area.

Description

[0001] 1. Field of the Invention[0002] The present invention relates to an active matrix type liquid crystal display device which thin film transistors (TFT) are arranged in a matrix form and these thin film transistors are used as switching elements.[0003] 2. Description of the Related Art[0004] An active matrix type TFT (Thin Film Transistor: hereinafter abbreviated as "TFT") liquid crystal display device in which TFTs are formed in a matrix arrangement on a glass substrate and these TFTs are used as switching elements has been developed as a high-quality flat-face display. In a twisted nematic (hereinafter abbreviated as "TN") type active matrix crystal display device which has been hitherto widely used, transparent electrodes which are formed on two glass substrates so as to confront each other are used as electrodes for driving a liquid crystal layer. By applying a voltage to liquid crystal molecules which are arranged in parallel to the substrate surface under non-voltage appl...

AI Technical Summary

Benefits of technology

This configuration prevents charge-up in the color filter layer, suppressing color shades and enhancing the visibility angle by maintaining the electric field's effect solely on the liquid crystal layer, thereby improving display characteristics without affecting the color filter.

Problems solved by technology

However, the inherent behavior of the liquid crystal voltages under voltage-applied state causes a problem that the angle of visibility of the TN type liquid crystal display device is small.

The problem that the angle of visibility is small is particularly remarkable in the rise-up direction of the liquid crystal molecules under a half tone display state.

However, in the IPS system, the color filter layer is disposed between the liquid crystal layer and the counter substrate, and thus the electric field which will be formed when potential is applied between the source electrode and the drawn-out common electrode adversely affects the color filter layer and degrades the display characteristic of the active matrix type liquid crystal display device.

When the color filter layer charges up, undesired electric field is applied to the liquid crystal molecules below the charge-up area of the color filter layer at all times, so that the display characteristic is adversely effected.

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