Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
1998-12-28
2001-10-30
Hjerpe, Richard (Department: 2674)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S089000, C345S090000, C345S092000
Reexamination Certificate
active
06310592
ABSTRACT:
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to a liquid crystal display (LCD), and more particularly to a LCD having a dual bank data driver structure and a driving method thereof.
(b) Description of the Related Art
The LCD is increasingly being used for the display device in televisions, personal computers and various other consumer appliances. The superior qualities of the LCD, such as low power consumption, thin profile, high resolution, light weight, etc., makes it be a future substitute for the traditional CRT displays.
LCDs apply an electric field to liquid crystal material of anisotropic dielectricity injected between two substrates to form a liquid crystal layer. The two substrates are arranged substantially parallel to one another having a predetermined gap therebetween, and the amount of light permeating the substrates is controlled by the intensity of the electric field applied to the liquid crystal material.
The LCD typically comprises a LCD panel including two substrates on which are formed a plurality of gate lines and data lines, a switching transistor and a pixel defined by the intersection of the gate lines and data lines. The LCD also comprises a gate driver that turns on each of the gate lines in sequence by applying a scanning signal; and a data driver (also called a source driver) that applies grey voltage corresponding to color signals to the data lines of the LCD panel in units of lines. The data driver and the gate driver are comprised of a plurality of data driver ICs and gate driver ICs, respectively.
If the electric field is applied to the liquid crystal layer, in the same direction continuously, the liquid crystal tends to degrades. Accordingly, image signals must be driven alternately between positive and negative values. Such a drive method is called an inversion driving method. Among the different types of the inversion driving methods, a frame inversion method inverts the image signals in units of frames, a line inversion method inverts the image signals in units of lines, and a dot inversion method inverts the image signals in units of pixels. When using a frame inversion method or a line inversion method, however, it is difficult to attain an optimal picture quality because of crosstalk and flicker problems.
Accordingly, a method recently used alternates the polarity of an image signal for common electrode voltage, supplied from the data driver ICs, between a positive polarity (+) and a negative polarity (−) in units of pixels. In more detail, after arranging the data driver ICs in a row on one of the two substrates of the LCD panel and electrically connecting a data line to an output terminal of each of the data driver ICs (hereinafter referred to as a single bank structure), a grey voltage output from each of the output terminals of the data driver ICs is controlled to change from positive to negative while being applied to the data lines, thereby alternating the polarity of the pixels from positive to negative.
In addition to the above typical single bank structure LCD, there has been developed a dual bank structure LCD in which data driver ICs are arranged on both the upper and lower substrates of the LCD panel. In the dual bank structure, odd (or even) data lines are connected to upper data driver ICs and even (or odd) data lines are connected to lower data driver ICs. However, with the dual bank structure LCD, as with the single bank structure LCD, if grey voltage output from the output terminals of the data drive ICs is applied to the data lines alternating from positive to negative, polarities of the pixels are inverted in (+)(+) and (−)(−) cycles. As a result, full dot inversion is not realized.
SUMMARY OF THE INVENTION
The present invention has been made in an effort to solve the above problems.
It is an object of the present invention to provide an LCD having a dual bank data driver structure realizing dot inversion and a driving method thereof.
To achieve the above object, the present invention provides an LCD having a dual bank data driver structure and a driving method thereof. The LCD includes an LCD panel including a plurality of gate lines, a plurality of data lines intersecting the gate lines, and a plurality of pixels arranged in a matrix and each having a switching element connected to the gate lines and the data lines, wherein the data lines are grouped into a plurality of data line groups and each data line group has an even number of adjacent data lines; a gate driver successively applying gate ON voltage to the gate lines to turn on the switching elements; and first and second data drivers provided on opposing sides of the LCD panel and to which the data line groups are alternately connected, the first and second data drivers applying grey voltages corresponding to image signals to the data lines via output terminals.
According to the present invention, the LCD further includes a timing signal generator for outputting timing signals to the first and second data drivers, and to the gate driver.
Another feature of the present invention is that the grey voltage is output at opposite polarities for adjacent output terminals of the first and second data drivers.
According to the present invention, each data line group is comprised of a pair of adjacent data lines.
According to the present invention, the timing signal generator includes a first divider receiving the R,G,B data input in series, and outputting a first R,G,B data each corresponding to odd R,G,B data among the R,G,B data and a second R,G,B data corresponding to even R,G,B data among the R,G,B data; a second divider receiving the first and second R,G,B data, and outputting a third R,G,B data corresponding to every other first R,G,B data beginning with a first of the same, a fourth R,G,B data corresponding to every other first R,G,B data beginning with a second of the same, a fifth R,G,B data corresponding to every other second R,G,B data beginning with a first of the same, and a sixth R,G,B data corresponding to every other second R,G,B data beginning with a second of the same; and a data selector for selectively outputting the third, fourth, fifth and sixth R,G,B data output from the second divider to the first and second data drivers, and which applies grey voltage to the data lines of the LCD panel such that grey voltage of opposite polarity is applied to adjacent data lines.
The method of driving the LCD according to the present invention includes the steps of applying gate ON voltage successively to the gate lines, and applying grey voltage to the data lines in units of lines through the first and second data drivers.
According to the present invention, the step of applying grey voltage to the data lines further includes the steps of receiving the R,G,B data input in series; outputting a first R,G,B data corresponding to odd R,G,B data among the R,G,B data and a second R,G,B data corresponding to even R,G,B data among the R,G,B data; receiving the first and second R,G,B data, and outputting a third R,G,B data corresponding to every other first R,G,B data beginning with a first of the same, a fourth R,G,B data corresponding to every other first R,G,B data beginning with a second of the same, a fifth R,G,B data corresponding to every other second R,G,B data beginning with a first of the same, and a sixth R,G,B data corresponding to every other second R,G,B data beginning with a second of the same; and selectively outputting the third, fourth, fifth and sixth R,G,B data to the first and second data drivers, and applying grey voltage to the data lines of the LCD panel such that grey voltage of opposite polarity is applied to adjacent data lines.
REFERENCES:
patent: 5604511 (1997-02-01), Ohi
patent: 5796379 (1998-08-01), Enomoto et al.
patent: 5808596 (1998-09-01), Kim
patent: 5945970 (1999-08-01), Moon et al.
Moon Hoi-Sik
Park Dong-won
Hjerpe Richard
Howrey Simon Arnold & White , LLP
Nguyen Kimnhung
Samsung Electronics Co,. Ltd.
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