Patent Application
20070216845
1. Field of the Invention
The present invention relates to a liquid crystal display panel and, more particularly, to a liquid crystal display panel whose conducting lines for transmitting control signals of the control integrated circuits have uniform resistance and capacitance.
2. Description of Related Art
Liquid crystal displays (LCDs) have gradually replaced cathode ray tubes (CRTs) in the market, and have been more and more appreciated by consumers. Liquid crystal displays not only have the advantage of compactness, but also have lower power consumption. Therefore, they have occupied an important position in almost every field of their application.
As shown in
In order to solve the above problem, the widths of the conducting lines 12 have been made different (the conducting line at the center is thinner, while the conducting lines at the left and right sides are thicker) to compensate for the non-uniform impedance caused by different lengths, as shown in
Therefore, there is need for an improved liquid crystal display panel which provides conducting lines with identical resistances and capacitances to allow for uniform impedance.
To achieve these and other advantages and in order to overcome the disadvantages of the conventional method in accordance with the purpose of the invention as embodied and broadly described herein, the present invention provides a conducting line design used in LCD panels, in which the lengths and widths of the conducting lines are made different to allow each line to have identical impedances. The plurality of conducting lines is formed in a fanlike shape and is used for transmitting control signals of the control integrated circuits (ICs) to the transistors. Each of the conducting comprises a respective width and a respective length. The width of the conducting lines increases towards the medial portion of the fanlike shape. Also, the length of the conducting lines increases towards the medial portion of the fanlike shape. The arrangement of the various lengths and widths make the resistance and capacitance of the conducting lines uniform.
An object of the present invention is to provide an LCD panel capable of producing high quality optical performance.
To achieve the above objects, an LCD panel of the present invention comprises a plurality of transistors, a plurality of control ICs for controlling switching of the transistors and inputting data to the transistors, and a plurality of conducting lines having identical resistances and capacitances for transmitting control signals of the control ICs to the transistors.
The conducting lines are straight lines, oblique lines, bending lines, zigzag shape, wavy shape, or other shape or pattern. Additionally, the conducting lines are one type of line or a combination of lines, shapes, or patterns.
Since the conducting lines have uniform impedance, the optical performance is improved.
These and other objectives of the present invention will become obvious to those of ordinary skill in the art after reading the following detailed description of preferred embodiments.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings:
FIGS. 3(a) and 3(b) are diagrams showing the electrical properties of a conventional liquid crystal display panel;
FIGS. 8(a) and 8(b) are diagrams showing the electrical properties of a liquid crystal display panel according to an embodiment of the present invention; and
Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
The present invention provides a conducting line design that makes the resistance and capacitance of each conducting line identical. Through change and proper combination of the length and width of each conducting line, the present invention allows the conducting lines to have the same electrical properties, thereby enhancing the image quality of the LCD panel.
The present invention makes use of impedance compensation to reduce the difference in resistance and capacitance between conducting lines. Refer to
As shown in
Similarly, in the direction to the left of center, Lm−1 is the same length as Lm+1, Lm−2 is the same length as Lm+2, and Lm−n is the same length as Lm+n.
The conducting line in the center of the fanlike shape has a width Wm. The first conducting line to the right of center has a width Wm+1 and the second conducting line to the right of center has a width Wm+2. Width Wm is the largest conducting line width. Wm is greater than Wm+1 which is greater than Wm+2, etc. The conducting line on the far right has a width of Wm+n, which is the smallest conducting line width.
Similarly, in the direction to the left of center, Wm−1 is the same width as Wm+1, Wm−2 is the same width as Wm+2, and Wm−n is the same width as Wm+n.
In
The first portion 22a of the conducting line can be a straight line, an oblique line, or a combination of straight line and oblique line to avoid the problem of a too close distance between conducting lines. Because the resistance of the conducting line 22 is inversely proportional to its cross sectional area and proportional to its length, the conducting lines 22 are arranged with the various lengths and widths in order to provide identical resistances and capacitances.
Refer to
In
The design of conducting lines in the above embodiments uses the resistance of the central conducting line 22 as a reference standard. First the width and length of the center conducting line is designed, and then the impedance of conducting lines 22 to the left and right sides of the center are made identical to the standard. Therefore, the widths and lengths of the conducting lines gradually decrease from the center toward the left and right sides.
Alternatively, another conducting line 22 (e.g., the outmost conducting line) can also be chosen as a reference standard for impedance compensation, and the widths and lengths of the conducting lines are changed accordingly from outside to inside to allow each conducting line to finally have identical resistances and capacitances.
The present invention further provides an LCD panel that utilizes the above conducting line design. Refer to
The gates of the transistors 24 are connected to the conducting lines 22 in the horizontal direction, and the drains of the transistors 24 are connected to the conducting lines 22 in the vertical direction. The conducting lines 22 in the horizontal direction are responsible for transmitting signals for controlling switching of the transistors 24. The control ICs 20 will turn on a row of transistors 24 each time, and send data into each transistor 24 in the row via the conducting lines 22 in the vertical direction, and then turn off the transistors 24. Data read in at this time will be stored in the transistors 24 in the form of charge until the control ICs 20 turn on the transistors 24 and store other data into the transistors 24.
Next, the control ICs 20 will turn on the next row of transistors 24, and input data into each transistor 24 in the row, and then turn them off. All the transistors 24 will undergo the above steps in order, and the whole frame data are thus stored into the corresponding transistors 24 and displayed on the panel. Alternatively, a conducting line 22 for transmitting data can be connected to more than one transistor 24, but these transistors 24 are controlled by different switching signals. Therefore, the sane conducting line 22 can be selected to transmit data to several transistors 24, thereby reducing the number of conducting lines and also lowering the cost.
Each conducting line 22 comprises a first portion 22a and a second portion 22b. The widths of the conducting lines 22 gradually increase from the left and right sides toward the medial portion, and the lengths of the conducting lines 22 gradually increase from the left and right sides toward the medial portion. The first portion 22a can be a straight line, an oblique line, or a combination of straight line and oblique line to avoid the problem of a too close of distance between conducting lines Also, the shape or pattern of the second portion 22b can be selected according to requirements.
This design can allow the conducting lines 22 for transmitting control signals and data signals to have the electrical properties curve shown in FIGS. 8(a) and 8(b), in which “left”, “center” and “right” represent the conducting lines at the left side, the center and the right side, respectively. Because each conducting line 22 in the figures has the same resistance and capacitance, the control signals that pass through won't have any inconsistency or delay phenomenon. Signals can be simultaneously transmitted to each controlled transistor 24 to maintain the wholeness of data to be displayed, thereby producing a display frame of high image quality.
In the above embodiment, the first portions 22a of the conducting lines 22 are connected to the transistors 24 of the LCD panel, and the second portions 22b are connected to the control ICs 20. The connection can also be reversed, as shown in
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the invention and its equivalent.
