The present invention relates to liquid crystal panels and liquid crystal displays (LCDs), and more particularly to an LCD panel and an LCD with a high aperture ratio.
Recently, LCDs that are light and thin and have low power consumption characteristics have been widely used in office automation equipment, video units and the like. Such kinds of LCDs typically include a twisted nematic (TN) mode LCD and a super twisted nematic (STN) mode LCD. Although TN-LCDs and STN-LCDs have been put to practical use in many applications, they generally have a very narrow viewing angle. In order to solve the problem of narrow viewing angle, In Plane Switching (IPS) LCDs have been developed.
A typical IPS LCD includes a plurality of pixel regions defined by a plurality of data lines and gate lines perpendicular to each other.
When a voltage is applied, a parallel main electric field 190 between the pixel and common electrode 131a, 133a is generated. However, at junctions of the zigzagged pixel electrodes 131a and the pixel lines 131b, the electric field is abnormal, and the liquid crystal molecules thereat cannot be driven properly. Distorted electrical field corresponding to the acute angle junction region and an obtuse angle junction region are produced. As shown in
Because the acute angle junction region has a smaller space than that of the obtuse angle junction region, the distorted electrical field 190a in the acute angle junction region has a sharper change of electrical field over a given distance than the distorted electrical filed 190b in the obtuse angle junction region. Thus, the transmission ratio of the obtuse angle junction region is higher than that of the acute angle junction region. However, the TFT 120 positioned at the obtuse angle junction region is opaque. That is, the TFT 120 blocks light beams that would otherwise be transmitted through a part of the obtuse angle junction region. This means that the TFT 120 further reduces the transmission ratio of the obtuse angle junction region. As a result, black regions corresponding to the obtuse angle junction region and the acute angle junction region are produced in a display of the IPS LCD 1.
What is needed, therefore, is a liquid crystal display panel which has an equally good visual performance at various different viewing angles and a high contrast ratio.
In a preferred embodiment, a liquid crystal display includes: a first substrate; a second substrate opposite to the first substrate; a plurality of liquid crystal molecules interposed between the first and second substrates; and a plurality of gate lines and data lines formed on the first substrate, thereby defining a plurality of pixel regions. Each pixel region has a pixel electrode assembly, a common electrode assembly spaced apart from the pixel electrode assembly and a plurality of transistor. The pixel electrode assembly has a pixel line and at least one pixel electrode, one of the at least one pixel electrode defining an acute angle junction region where said one of the at least one pixel electrode adjoins the pixel line. The common electrode assembly has a common line and at least one common electrode. Each transistor is positioned at the acute angle junction region.
In another preferred embodiment, a panel includes a substrate defining a plurality of pixel regions. Each pixel region has a pixel electrode assembly and a plurality of transistor. The pixel electrode assembly includes a pixel line, at least one pixel electrode. One of the at least one pixel electrode defines an acute angle junction region where the pixel electrode adjoins the pixel line. Each transistor is positioned at the acute angle junction region.
In still another preferred embodiment, a liquid crystal display includes: a first substrate; a second substrate opposite to the first substrate; a plurality of liquid crystal molecules interposed between the first and second substrates; and a plurality of gate lines and data lines formed on the first substrate, thereby defining a plurality of pixel regions. Each pixel region has a pixel electrode assembly, a common electrode assembly spaced apart from the pixel electrode assembly and a plurality of transistor. The pixel electrode assembly has a pixel line and at least one pixel electrode, one of the at least one pixel electrode defining a lower light transmission region and a higher light transmission region at two sides of each pixel electrode where said one of the at least one pixel electrode adjoins the pixel line. The common electrode assembly has a common line and at least one common electrode. Each transistor is positioned at an intersection of the data line and the gate line, corresponding to one lower transmission region.
Other advantages and novel features will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:
Referring to
The pixel electrode assembly 431 and the common electrode assembly 433 are each generally comb-shaped. That is, each of the pixel electrode assembly 431 and the common electrode assembly 433 has gently zigzagged-shaped tooth portions, which are uniformly spaced apart from each other. In particular, the common electrode assembly 433 includes a common line 433b, and a plurality of gently zigzagged common electrodes 433a. The pixel electrode assembly 431 includes a pixel line 431b, and a plurality of gently zigzagged pixel electrodes 431a. First ends of the zigzagged pixel electrodes 431a integrally connect with the pixel line 431b respectively. Each zigzagged pixel electrode 431a defines an acute angle α4 and an obtuse angle β4 at two respective sides thereof where it adjoins the pixel line 431b. The acute angle α4 angle and the obtuse angle β4 are supplementary angles. The acute angle α4 defines an acute angle junction region (not labeled) thereat, and the obtuse angle β4 defines an obtuse angle junction region (not labeled) thereat.
The TFT 420 is positioned at an intersection of the pixel line 431b and one pixel electrode 431a, corresponding to one acute angle junction region α4. The TFT 420 has a gate electrode (not labeled), a source electrode (not labeled), and a drain electrode (not labeled), which are connected to the gate line 413, the data line 415, and the pixel electrode assembly 431 respectively. Specially, the TFT 420 is positioned adjacent to an intersection of the gate line 413 and the data line 415.
The zigzagged pixel electrodes 431a of the pixel electrode assembly 431 and the zigzagged common electrodes 433a of the common electrode assembly 433 are arranged one next to the other in alternating fashion, parallel to each other and uniformly spaced apart. Therefore when a voltage is applied at the pixel region, a parallel main electrical field 490 between the zigzagged pixel electrodes 431a and the zigzagged common electrodes 433a is produced. At the same time, a distorted electrical field 490a at the acute angle junction region and a distorted electrical field 490b at the obtuse angle junction region are also respectively produced. Thus, a plurality of liquid crystal molecules 430b in the distorted electrical fields 490a, 490b have a different orientation from that of a plurality of liquid crystal molecules 430a in the main electrical field 490. Because the distorted electrical field 490a at the acute angle junction region has a sharper change over a given distance than that of the obtuse angle junction region, fewer light beams transmit through the acute angle junction region than through the obtuse angle junction region. That is, the obtuse angle junction region has a higher transmission ratio than that of the acute angle junction region.
The LCD 4 according to the first preferred embodiment utilizes the TFT 420 positioned at the acute angle junction region having a lower transmission ratio to efficiently use the region with a lower transmission ratio and save the region with a higher transmission ratio. Therefore, the LCD 4 increase the transmission ratio and the aperture ratio of the pixel region.
Referring to
Referring to
It is to be understood, however, that even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
Number | Date | Country | Kind |
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94205940 | Apr 2005 | TW | national |