Liquid crystal display device

Abstract

This invention offers a liquid crystal display device according to FFS technology, which is capable of sufficiently providing a common electrode with common electric potential and improving an aperture ratio of pixels to obtain a bright display. A pixel electrode is formed of a first layer transparent electrode. A common electrode made of a second layer transparent electrode is formed above the pixel electrode interposing an insulation film between them. The common electrode in an upper layer is provided with a plurality of slits. The common electrode extends over all the pixels in a display region. An end of the common electrode is disposed on a periphery of the display region and connected with a peripheral common electric potential line that provides a common electric potential Vcom. There is provided neither an auxiliary common electrode line nor a pad electrode, both of which are provided in a liquid crystal display device according to a conventional art.

Description

CROSS-REFERENCE OF THE INVENTION[0001]This application claims priority from Japanese Patent Application No. 2006-204624, the content of which is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention relates to a liquid crystal display device, specifically to a liquid crystal display device in which an alignment direction of liquid crystal molecules is controlled by a lateral electric field generated between a pixel electrode and a common electrode.[0004]2. Description of the Related Art[0005]As a way to achieve a wide viewing angle of the liquid crystal display device, a method has been developed to realize a light switching function by rotating the liquid crystal molecules in a plane parallel to a substrate with a lateral electric field generated between the electrodes on the same substrate. In-Plane Switching (hereafter referred to as IPS) technology and Fringe-Field Switching (hereafter referred to as FFS) ...

AI Technical Summary

Benefits of technology

[0017]When the auxiliary common electrode line 15 is disposed within the display region, however, there is a problem that its wiring portion makes a light-shielding region to reduce an aperture ratio of the pixels. This invention is directed to offer a liquid crystal display device capable of securely providing the common electrode with the common electric potential sufficiently and improving the aperture ratio of the pixels to obtain a bright display.

Problems solved by technology

Since the common electrode 23 is formed of the transparent electrode such as ITO that has higher sheet resistivity than ordinary metal, the degradation in the quality of display is prone to be caused.

This problem becomes evident particularly as a panel size of the liquid crystal display device becomes larger.

When the auxiliary common electrode line 15 is disposed within the display region, however, there is a problem that its wiring portion makes a light-shielding region to reduce an aperture ratio of the pixels.

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