JPH06175619A - Method for driving liquid crystal pannel - Google Patents

Abstract

PURPOSE:To remove lines with the same polarity between frames, to prolong the life of a liquid crystal pannel and to suppress a flicker in a display image by reversing the polarity at every one frame (two fields). CONSTITUTION:At the time of AC driving with a twice write drive system or a two rows simultaneous system, the polarity is reversed at every one frame of a pixel 2 in a liquid crystal pannel 1, and the polarity is reversed at every two lines in a field constituting each frame. That is, the polarity of the second lines of first and second fields in a first frame are reversed to the same of the second lines of third and fourth fields in a second frame, and further, the sames of the fourth lines, etc., in the same fields as the abovementioned fields are reversed to each other as well. Thus, though the frequency of the flicker in the display image becomes low, the flicker is inconspicious since the phase of a peripheral pixel 2 is reversed, and the flicker is suppressed, and the life of the liquid crystal pannel 1 is prolonged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC driving method for a liquid crystal display device, and more particularly to a driving method for a liquid crystal panel which suppresses image flicker of the liquid crystal panel.

[0002]

2. Description of the Related Art Conventionally, as a driving method of this type of liquid crystal panel, a double writing method and a two-row simultaneous driving method for converting an interlaced image into a non-interlaced image without using a line memory have been adopted. .

As already known, the above-mentioned double writing drive system is, for example, shown in FIGS. 5 (a) to 5 (e) and FIG.
As shown in (a) to (e), the polarity of the driver output for driving the liquid crystal panel is inverted for each horizontal line of each field (shown in FIGS. 5B and 6B), and the liquid crystal panel The output of the gate for driving each pixel is set to 2 pulses for each line (shown in FIGS. 5 (c) to (e) and 6 (c) to (e)).

Further, the two-row simultaneous drive system is, for example, as shown in FIGS. 5 (a), 5 (b),
As shown in (f) to (h) and FIGS. 6 (a), (b), (f) to (h), the polarity of the driver output for driving the liquid crystal panel is inverted for each horizontal line of each field ( 5 (b) and 6 (b)), and the output of the gate for driving each pixel of the liquid crystal panel is simultaneously set to two pulses for each line (FIGS. 5 (c) to 5 (e), 6 ()). c) to (e)
Shown in).

In the above driving method, for example, as shown in FIGS. 7 and 8, the polarity of AC driving is inverted every horizontal line of the liquid crystal panel 1, that is, the voltage applied to each pixel 2 of the liquid crystal panel 1. The polarity is reversed to prolong the life of the liquid crystal panel 1. In addition, in FIG. 7 and FIG.
“+” And “−” represent the polarities of each pixel 2.

[0006]

However, in the above-mentioned liquid crystal panel driving method, as shown in FIGS. 7 and 8, the second and fourth lines of the first and second fields of the first frame are used. Have the same polarity, and the same line has the same polarity for each frame, so that a DC component remains in the pixel 2 portion of each line, which only deteriorates the life of the liquid crystal panel 1. Instead, flicker will occur on the display screen.

The present invention has been made in view of the above problems, and an object thereof is to improve the life of the liquid crystal panel and suppress the flicker of the displayed image even in the double writing drive system and the double row simultaneous drive system. An object of the present invention is to provide a method of driving a liquid crystal panel that can be performed.

[0008]

In order to achieve the above object, according to the present invention, when a liquid crystal panel is driven, a horizontal line of the liquid crystal panel is AC-driven by a double writing method, or
In a method for driving a liquid crystal panel that is AC-driven by a row-simultaneous driving method, the polarity is inverted for each frame of a display image signal of the liquid crystal panel, and the polarity is inverted for every two lines of fields constituting each frame. Is the gist.

[0009]

With the above method, the polarities of the horizontal lines (2 lines) of the liquid crystal panel are inverted every frame, that is, the first field and the second line of the first frame.
The polarity reversal of the field of
Since the polarities in the third field and the fourth field, which correspond to the frame, are reversed, there is no horizontal line that remains the same polarity. As a result, the flicker frequency of the display image on the liquid crystal panel becomes as low as 15 Hz, but since the phases of the surrounding pixels are inverted, the flicker is inconspicuous and, as a result, the flicker can be suppressed. Moreover, the life of the liquid crystal panel can be further extended.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS. In the figure, the same parts as those in FIGS. 5 to 8 are designated by the same reference numerals, and a duplicate description will be omitted.

As shown in FIGS. 1 and 2, in the method of driving a liquid crystal panel according to the present invention, when the liquid crystal panel is driven, the horizontal lines of the liquid crystal panel are AC-driven by a two-row simultaneous driving method or twice. In the driving method of a liquid crystal panel that is AC-driven by the writing method, the polarity inversion in the first and second fields of the first frame is the same as the conventional one, and the polarity in the third and fourth fields corresponding to the second frame is inverted. That is, that is, the polarity is inverted every one frame (two fields).

In this case, for the first field and the second field of the first frame, as shown in the schematic view of the liquid crystal panel of FIG. 1 and the time charts of FIGS. 5 and 6, each pixel 2 of the liquid crystal panel 1 While the polarity of the field for driving the liquid crystal is inverted as in the conventional case, the liquid crystal panel of FIG. 2 is used for the third field and the fourth field of the second frame, and as shown in the time charts of FIGS. The polarity of the field driving each pixel of the panel 1 is inverted.

In the second frame, the third field has a polarity opposite to that of the first field of the first frame, and the fourth field has a polarity opposite to that of the second field of the first frame. That is, regarding the driver output of the liquid crystal panel 1, for example, when the polarity of the line 1 of the first field is positive and the polarity of the line 2 of the same field is negative (shown in FIG. 5B), the line of the third field 1
Has a negative polarity, and the line 2 in the same field has a positive polarity (shown in FIG. 3B). Further, for example, the polarity of the line 262 of the second field is negative, and the line 2 of the same field
If the polarity of 63 is positive (as shown in FIG. 6B), the fourth
The field line 262 has a positive polarity, and the field line 263 has a negative polarity (shown in FIG. 4B).

That is, as is apparent from FIGS. 1 and 2, the second line and the fourth line of each frame, that is, the second line of the first and second fields and the second line of the third and fourth fields. Are reversed, the polarities of the fourth line of the first and second fields are reversed, and the polarities of the fourth line of the third and fourth fields are reversed, and the polarities of the following lines are reversed.

As a result, when the liquid crystal panel 1 is driven, the frequency of the flicker of the display image on the liquid crystal panel 1 becomes as low as 15 Hz, but the flicker is noticeable because the phases of the surrounding pixels are inverted. In addition, it is possible to suppress the flicker of the result display image and further prolong the life of the liquid crystal panel 1.

[0016]

As described above, according to the liquid crystal panel driving method of the present invention, the polarity is inverted every one frame (two fields) in the double write driving method and the two-row simultaneous driving method. Therefore, it is possible to eliminate lines having the same polarity between frames, which can prolong the life of the liquid crystal panel and suppress flicker of a display image.

[Brief description of drawings]

FIG. 1 is a schematic partial schematic view of a liquid crystal panel to which an embodiment of the present invention is applied, to which a liquid crystal panel driving method is applied.

FIG. 2 is a schematic partial schematic view of a liquid crystal panel to which the driving method of the liquid crystal panel is applied according to the embodiment of the present invention.

FIG. 3 is a schematic time chart diagram illustrating the operation of the liquid crystal panel driving method according to the embodiment of the present invention.

FIG. 4 is a schematic time chart diagram for explaining the operation of the liquid crystal panel driving method according to the embodiment of the present invention.

FIG. 5 is a schematic time chart diagram illustrating an operation of a conventional liquid crystal panel driving method.

FIG. 6 is a schematic time chart diagram illustrating an operation of a conventional liquid crystal panel driving method.

FIG. 7 is a schematic partial schematic view of a liquid crystal panel to which a conventional liquid crystal panel driving method is applied.

FIG. 8 is a schematic partial schematic view of a liquid crystal panel to which a conventional liquid crystal panel driving method is applied.

[Explanation of symbols]

 1 LCD panel 2 pixels

Claims (1)

[Claims] 1. A method of driving a liquid crystal panel, wherein a horizontal line of the liquid crystal panel is AC-driven by a double writing method or a two-row simultaneous driving method, the method comprising: The polarity is inverted for each frame, and 2 of the fields that make up each frame
A method for driving a liquid crystal panel, which is characterized in that the polarity is inverted for each line.