JPH04260286A - Drive method for liquid crystal display device - Google Patents

Abstract

PURPOSE:To allow a liquid crystal display device corresponding to one High Vision device to implement HDTV display and EDTV display. CONSTITUTION:Scanning lines of a liquid crystal display panel 1 are extracted alternately from the left and right and given to 2 systems of X drivers 2, 3, and in the case of High Vision display, the two systems of the X side drivers 2, 3 are selected alternately for each field to apply interlace drive. On the other hand, in the case of the EDTV display, the two scanning lines connecting to the X side drivers 2, 3 are selected simultaneously and one pattern is formed by one field to implement noninterlace drive.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to high-definition display and ED.
The present invention relates to a driving method for realizing TV display using the same liquid crystal display device.

0002

[Prior Art] The drive system for high-definition LCD projection televisions has nine Y-side drivers arranged at the top and bottom of the liquid crystal panel, and adjacent pixels are alternately driven by the Y-side drivers at the top and bottom of the liquid crystal panel. At the same time, the LCD panel screen was divided horizontally into nine blocks, and an interlaced driving method was adopted in which each divided screen was displayed simultaneously. "Drive Circuit System for LCD Projection Television", 1989 Institute of Electronics, Information and Communication Engineers Autumn National Conference, C-29 (1989)).

FIG. 5 is a block diagram of a liquid crystal display module consisting of a liquid crystal panel and a driver having a sufficient number of signal lines for displaying high-definition signals.

In FIG. 5, the 1,000 scanning lines 4 of the liquid crystal panel 1, which correspond to a full line of high-definition signals, are separated into left and right lines for each line, with an X-side driver 2 on the left and an X-side driver 3 on the right. It is connected to two systems of X-side drivers.

Similarly, the 1296 signal lines 5 of the liquid crystal panel
are separated into upper and lower lines for each line, and are connected to two Y-side drivers, the upper Y-side driver 6 and the lower Y-side driver 11, to send the A/D converted video signal to the upper and lower Supply from the row direction.

FIG. 6 is a diagram showing the order of scanning lines selected in the driving method of an interlaced liquid crystal display device.

In the odd field of FIG. 6, G1 and G3
, . . . positive polarity video signals from the odd-numbered scanning lines 4 and the upper Y-side driver 6 selected in the order of G999,
A video signal of +-...+- polarity is displayed on the odd-numbered display electrodes provided near the intersection with the signal line to which the negative-polarity video signal from the lower Y-side driver 11 is applied. .

A video signal of negative polarity is applied from the even-numbered scanning line 4 selected in the even-numbered field, a video signal of negative polarity is applied from the upper Y-side driver 6, and a video signal of positive polarity is applied from the lower Y-side driver 11. A video signal having a polarity of -+...-+ is displayed on display electrodes in even-numbered rows provided near the intersections with the signal lines.

One frame is composed of an odd field and an even field, and in the next frame, the polarity of the video signal applied from each Y-side driver is reversed.

FIG. 7 is a diagram showing the order of scanning lines selected in the driving method of a non-interlaced liquid crystal display device.

[0011] In the odd field in FIG.
Even-numbered scanning lines are alternately G1, G2,..., G100
Selected in the order of 0.

During the odd field, a positive video signal is provided to the display electrode provided near the intersection of the odd numbered scanning line and the signal line, and a positive video signal is provided to the display electrode provided near the intersection of the even numbered scanning line and the signal line. A video signal of negative polarity is applied to each display electrode.

During the even field, a video signal of negative polarity is provided on the display electrode provided near the intersection of the odd numbered scanning line and the signal line, and a video signal of negative polarity is provided at the intersection of the even numbered scanning line and the signal line. A video signal of positive polarity is applied to each of the display electrodes.

[0014] EDTV display on a liquid crystal panel has also been displayed using a non-interlaced driving method, but a driving method for a liquid crystal display device that performs EDTV display and high-definition display in one liquid crystal display device is not well known. do not have.

The synchronizing signal extraction circuit and the field discrimination circuit perform interlaced scanning of the scanning lines of the liquid crystal panel, and non-interlaced scanning by simultaneously selecting two adjacent scanning lines of the liquid crystal panel. Driving method for a liquid crystal display device that provides a natural image even when it is difficult to distinguish between even and odd fields of a video signal applied to the liquid crystal display device by making it possible to select the state under specific conditions. There was (Unexamined Japanese Patent Publication No. 6)
4-65987).

FIG. 8 shows a drive circuit for various signals according to a conventional method for driving a matrix type liquid crystal display device.

In FIG. 8, an X-side driver 2 for odd-numbered scanning lines and an X-side driver 3 for even-numbered scanning lines are arranged on the left and right sides of a liquid crystal panel 1, respectively, and 400 scanning lines 4 are transmitted from the X-side driver. A scanning signal is supplied to.

The left X-side driver 2 applies odd-numbered scanning lines 4 from 1st to 399th, and the right X-side driver 2
It is connected to the scanning lines 4 from number 400 to number 400.

A Y-side driver 6 for supplying video signals is connected to 640 signal lines 5 intersecting with 400 scanning lines 4 of the liquid crystal panel 1.

Odd or even field video signal 7
is applied to the Y-side driver 6 through a video amplifier 8, and is converted into a horizontal synchronization signal, a vertical synchronization signal and a field signal by a synchronization signal extraction circuit 9.

The field signal from the extraction circuit 9 is applied to the discrimination circuit 10 and converted into a signal for simply selecting the left and right X-side drivers 2 and 3 either simultaneously or alternately.

However, in the conventional method for driving a liquid crystal display device, when it is difficult to distinguish between even and odd conditions, the liquid crystal display device is obviously driven by non-interlace scanning.

[0023]

SUMMARY OF THE INVENTION An object of the present invention is to selectably display high-definition signals and EDTV signals having different horizontal scanning frequencies on one liquid crystal display device.

[0024]

[Means for Solving the Problems] The present invention provides at least an X-side scanning line corresponding to a full line of a high-definition signal and a
In a method for driving a liquid crystal display device having side signal lines,
The switching circuit and the X-side driver selection circuit connect each scanning line of the liquid crystal display device to two separate systems of X-side drivers, and connect the two separate systems of X-side drivers to one field. High-definition display is performed by interlacing each drive, and the two adjacent X-side drivers are connected to
The present invention is characterized in that it is possible to select EDTV display by selectively driving each set of scanning lines and simultaneously driving two lines constituting one screen in one field.

[0025]

[Operation] Since two systems of X-side drivers with a simple shift register configuration are connected separately for each scanning line, in odd-numbered fields, the odd-numbered rows connected to the first system of X-side drivers The scanning lines are driven, and in even-numbered fields, the scanning lines in even-numbered rows connected to the X-side driver of the second system are driven.

With this driving method, interlaced high-definition display is achieved. In the case of EDTV display, the adjacent odd and even row scanning lines are divided into two for each field.
By driving line by line and displaying one screen, display is achieved by driving two lines simultaneously.

[0027]

[Examples] Examples of the present invention will be described below.

As a method for displaying video signals on a liquid crystal panel, HDTV and EDTV can be displayed on one liquid crystal display device by applying scanning signals to scanning lines at predetermined timings. Adjustment is necessary because the frequencies and phase relationships between the two are different.

For example, for horizontal scanning frequency HDTV
is 33.75kHz, and EDTV is 31.5kHz.

Therefore, in various cases, it is necessary to switch between different characteristics. FIG. 1 is a circuit diagram of a liquid crystal display module according to the present invention, which comprises a liquid crystal panel having a sufficient number of signal lines for displaying high-definition signals and a driver equipped with a switching circuit.

In the liquid crystal panel 1 shown in FIG. 1, the 1000 scanning lines are separated into left and right lines for each line, and are sent to two systems of X-side drivers: the left X-side driver 2 and the right X-side driver 3. The 1296 signal lines are separated vertically for each line, and are connected to the upper Y side driver 6 and the lower Y side driver 6.
It is connected to the two Y-side drivers of the side driver 11 and supplies video signals from the upper and lower column directions.

[0032] The horizontal synchronizing signal 12 is sent to the PLL 13, and the LCA
A vertical synchronizing signal 20 is input to each of the terminals 15 and 15, respectively.

In FIG. 1, the horizontal synchronizing signal 12 is output to the Y side driver 6 by the PLL 13 which is locked with the horizontal synchronizing signal.
, 11 sampling clocks are created, but HD
Since the horizontal scanning frequency is different between the TV and the EDTV, the time constant is changed over by the switch A14.

The video signal 7 and the timing signal from the LCA 15 are input to the video AMP polarity inversion circuit 19 .

Next, the LCA 15 switches between two memories, the memory A 17 and the memory B 18, by the switch B 16, so that the LCA 15 in the case of HDTV and EDTV is
Switch the input signals to the input signals, create timing signals that match each one inside the LCA 15, and connect the X side drivers 2 and 3, the Y side drivers 6 and 11, and the video AMP polarity inversion circuit 1.
9 is being input.

The circuit configuration shown in FIG. 1 allows HDTV and EDTV
Switching between displays is performed smoothly.

FIG. 2 is a timing chart of scanning lines when high-definition display is performed using the driving method of the present invention.

With the added set of memory and switch, in the case of an HDTV video signal, the interlaced HDTV video signal is displayed as a full screen on the liquid crystal panel.

Further, the left and right X-side drivers are selected for each field and are operated alternately.

That is, in an odd field, the right X-side driver is stopped, and the left X-side driver selects and drives the odd-numbered scanning lines of the liquid crystal panel sequentially from 1st to 3rd to 999th line. In the following even field, the left X side driver
2 by stopping the right X-side driver and sequentially selecting and driving the even-numbered scanning lines 2, 4, ... up to 1000 lines.
An interface where one screen is made up of fields (one frame).
A racing system has been realized.

In FIG. 2, between two vertical synchronizing signals 20, a number of horizontal synchronizing signals 12 equal to or greater than the number of scanning lines of the liquid crystal panel are normally generated, and the scanning signals 21 are applied to the scanning lines in accordance with the horizontal synchronizing signals 12. is applied.

Gn in the figure indicates the scanning signal for the n-th row of the liquid crystal panel. The scanning signal 21 is applied to the odd-numbered scanning line of the liquid crystal panel between two vertical synchronizing signals 20, and then It can be seen from FIG. 2 that the period between the two vertical synchronizing signals 20 is applied to the even-numbered scanning lines of the liquid crystal panel.

FIG. 3 is a timing chart when two scanning lines are simultaneously driven when performing EDTV display using the driving method of the present invention.

EDTV by the selection circuit of the X side driver.
In the case of a video signal, the video signal is converted to a non-interlaced video signal and displayed as a partial screen in a liquid crystal display device.

Further, the left and right X-side drivers located on the left and right sides of the liquid crystal panel and connected alternately to the left and right scanning lines are driven simultaneously.

That is, when the first scanning line corresponding to the left X-side driver is selected in a certain field, the second scanning line corresponding to the right X-side driver is also selected at the same time. so that

[0047] Sequentially 3,
A non-interlace method is realized by selectively driving 4 lines, 5 lines, 6 lines, ...999 lines, 1000 lines, etc., and simultaneously scanning two scanning lines that make up one screen in one field. .

In FIG. 3, between two vertical synchronizing signals 20, a number of horizontal synchronizing signals 12 equal to or greater than the number of rows of scanning lines on the liquid crystal panel are normally generated. At the same time, a scanning signal 21 is applied.

If Gn in the figure indicates the scanning signal for the n-th row of the liquid crystal panel, the scanning signal 21 is applied to all scanning lines of the liquid crystal panel between the two vertical synchronizing signals 20. It can be seen from 3.

FIG. 4 shows a video signal switching process diagram in the method for driving a liquid crystal display device of the present invention.

In FIG. 4, a video signal 7 is discriminated by a video signal discrimination circuit 22 into HDTV and EDTV.

Subsequently, the HDTV and EDTV signals are applied to the switching circuit 23, and then the HDTV and EDTV signals are applied to the switching circuit 23.
The signal is converted into two types of timing signals: an interlace scan of the V signal and a non-interlace scan of the EDTV signal.

Furthermore, the timing signal is
The signal is applied to a selection circuit 24 and converted into an interlaced signal 25 for alternately selecting odd and even scanning lines and a non-interlacing signal 26 for simultaneously selecting two scanning lines.

[0054]

[Effects of the Invention] As described above, according to the present invention,
A liquid crystal display device with scanning lines equivalent to one HDTV
Display of both DTV and EDTV becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a driving circuit diagram of a liquid crystal display device of the present invention.

FIG. 2 is a timing diagram of interlaced driving signals of the present invention.

FIG. 3 is a timing diagram of a non-interlaced drive signal of the present invention.

FIG. 4 is a diagram of video signal switching processing according to the present invention.

FIG. 5 is a wiring diagram of a liquid crystal panel compatible with high-definition display.

FIG. 6 is an explanatory diagram of an interlace method.

FIG. 7 is an explanatory diagram of a non-interlace method.

FIG. 8 is a drive circuit diagram of a conventional liquid crystal display device.

[Explanation of symbols]

1.LCD panel 2 X side driver 3 X side driver 4 Scanning line 5 Signal line 6 Y side driver 7 Video signal 8 Video amplifier 9 Extraction circuit 10 Discrimination circuit 11 Y side driver 12 Horizontal synchronization signal 13 PLL 14 Switch A 15 LCA 16 Switch B 17 Memory A 18 Memory B 19 Video AMP polarity inversion circuit 20 Vertical synchronization signal 21 Scanning signal 22 Video signal discrimination circuit 23 Switching circuit 24 X side driver-selection circuit 25 Interlace signal 26 Non-interlaced signal

Claims (1)

[Claims] Claim 1: In a method for driving a liquid crystal display device having an X-side scanning line and a Y-side signal line corresponding to at least a full line of a high-definition signal, the scanning line of the liquid crystal display device is divided into two separate systems for each line. The X-side driver of the two separate systems is connected to the 1. A method for driving a liquid crystal display device, which performs EDTV display by selectively driving two adjacent sets of scanning lines and simultaneously driving two lines constituting one screen in one field.