JP3101331B2 - Driving method of liquid crystal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high definition display and an ED.
The present invention relates to a driving method for realizing TV display with the same liquid crystal display device.

[0002]

2. Description of the Related Art In a drive system for a high-definition liquid crystal projection television, nine Y-side drivers are arranged above and below the liquid crystal panel, and adjacent pixels are alternately driven by the Y-side drivers above and below the liquid crystal panel. At the same time, the LCD screen was divided into nine blocks in the horizontal direction, and an interlaced driving method of simultaneously displaying each of the divided screens was adopted (ren, Nakai, Noda, Kubota, Miki, Hi-Vision Drive System for Liquid Crystal Projection Television for Television ", 1989 IEICE Autumn National Convention, C-29 (1989)).

FIG. 5 is a block diagram of a liquid crystal display module comprising a liquid crystal panel having a sufficient number of signal wires for displaying a high definition video signal and a driver.

In FIG. 5, scanning lines 4 of 1000 liquid crystal panels 1 corresponding to a full line of a Hi-Vision signal are separated into right and left for each line, and a left X-side driver-2 and a right X-side driver-3 are provided. Are connected to the two X-side drivers.

Similarly, 1296 signal lines 5 of the liquid crystal panel
Are vertically separated for each line, and connected to two Y-side drivers, an upper Y-side driver 6 and a lower Y-side driver 11, respectively, to convert the A / D-converted video signal into upper and lower parts. Supply from the column direction.

FIG. 6 is a diagram showing the order of the scanning lines selected by the driving method of the interface type liquid crystal display device.

In the odd-numbered fields shown in FIG.
The odd-numbered scanning lines 4 and the positive video signal from the upper Y driver 6 and the negative video signal from the lower Y driver 11 are applied in the order of G999. The display electrodes of the odd-numbered rows provided near the intersections with the signal lines to be displayed by the video signals of the polarity of +-.. +-.

[0008] A negative video signal is applied from the even-numbered scanning line 4 selected in the even field and the upper Y driver 6, and a positive video signal from the lower Y driver 11 is applied. The display is performed by the video signal of the polarity of-+ ..- + on the display electrodes of the even-numbered rows provided near the intersection with the signal line.

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

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

In the odd-numbered field shown in FIG.
The even-numbered scanning lines are alternately G1, G2,.
0 is selected in order.

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

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

Although the EDTV display on the liquid crystal panel is also displayed by the non-interlace type driving method, the driving method of the liquid crystal display device for performing the EDTV display and the high definition display in one liquid crystal display device is not well known. Absent.

A state in which the scanning lines of the liquid crystal panel are interface-scanned by the synchronizing signal extraction circuit and the field discriminating circuit, and two adjacent scanning lines of the liquid crystal panel are simultaneously selected to perform non-interlace scanning. And a method for driving a liquid crystal display device that provides a natural image even when it is difficult to determine whether the field of a video signal applied to the liquid crystal display device is even or odd. (Japanese Unexamined Patent Publication No.
4-65887).

FIG. 8 shows a driving circuit for various signals according to a conventional driving method of 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 the liquid crystal panel 1, respectively. Are supplied with a scanning signal.

The left X-side driver-2 is connected to odd-numbered scanning lines 4 from No. 1 to 399, and the right X-side driver is connected to 2nd.
It is connected to the scanning lines 4 from No. 400 to No. 400.

A Y driver 6 for supplying a video signal is connected to 640 signal lines 5 intersecting 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 synchronizing signal, a vertical synchronizing signal and a field signal by an extracting circuit 9 for synchronizing signals.

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

However, in the above-mentioned conventional method of driving a liquid crystal display device, when it is difficult to discriminate between even and odd, the liquid crystal display device is driven by non-interlaced scanning as obvious.

[0023]

SUMMARY OF THE INVENTION It is an object of the present invention to selectively display a Hi-Vision signal and an EDTV signal having different horizontal scanning frequencies on a single liquid crystal display device.

[0024]

According to the present invention, an X-side scanning line corresponding to at least a full line of a high-definition signal and a Y-side scanning line are provided.
In the method for driving a liquid crystal display device having a signal line on the side,
The scanning lines of the liquid crystal display device are connected to two separate X-side drivers for each line by a switching circuit and an X-side driver-selection circuit, and the two separate X-side drivers are connected to one field. The interface drive is performed every time to display a high-definition image.
It is characterized in that EDTV display can be selected by simultaneously driving two lines constituting one screen by one field by selectively driving each set of scanning lines.

[0025]

In the odd-numbered field, the odd-numbered rows of the odd-numbered rows connected to the first-type X-side driver are connected because the two-system X-side drivers having a simple shift register configuration are separately connected for each scanning line. The scanning lines are driven, and in the even-numbered fields, the scanning lines in the even-numbered rows connected to the second-system X-side driver are driven.

According to this driving method, an HDTV display of an interface system is performed. In the case of the EDTV display, two adjacent odd-numbered and even-numbered scanning lines are provided for each field.
By driving one line and displaying one screen, display by simultaneous driving of two lines is performed.

[0027]

Embodiments of the present invention will be described below.

As a method of displaying a video signal on a liquid crystal panel, an HDTV and an EDTV can be displayed on a single liquid crystal display device by applying a scanning signal to a scanning line at a predetermined timing. It needs to be adjusted because they differ in the frequency and phase relationship between the two.

For example, for the horizontal scanning frequency, the HDTV
Is different from 33.75 kHz and EDTV is 31.5 kHz.

Therefore, it is necessary to switch different characteristics in various cases. 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 a Hi-Vision signal and a driver having a switching circuit.

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

The horizontal synchronizing signal 12 is supplied to the PLL 13 by the LCA.
The vertical synchronizing signal 20 is input to 15.

In FIG. 1, the horizontal synchronizing signal 12 is controlled by the PLL 13 locked by the horizontal synchronizing signal.
Although 6 and 11 sampling clocks are created,
Since the horizontal scanning frequency differs between the DTV and the EDTV, the time constant is switched by the switch A14.

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

Next, the LCA 15 switches between the 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 switched.
Input signals to the X-side drivers 2, 3 and the Y-side drivers 6, 11 and the video AMP polarity inverting circuit 1.
9 has been entered.

HDTV and EDTV by the circuit configuration of FIG.
Switching in the case of display is performed smoothly.

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

With an additional set of memory and switch, in the case of an HDTV video signal, the entire screen is displayed on the liquid crystal panel as an interface type HDTV video signal.

The left and right X-side drivers are selected and operated alternately for each field.

That is, in the odd field, the right X-side driver is stopped, and the left X-side driver selectively drives the odd rows of the scanning lines of the liquid crystal panel up to 1, 3,... On the subsequent even-numbered field, the left X-side driver
Is stopped, and the even-numbered rows of the scanning lines are sequentially driven to 2, 4,...
An interface that composes one screen with one field (one frame)
The racing system is realized.

In FIG. 2, between the two vertical synchronizing signals 20, the number of horizontal synchronizing signals 12 equal to or more than the number of scanning lines of the liquid crystal panel is normally generated. Is applied.

In the drawing, Gn indicates a scanning signal on the n-th row of the liquid crystal panel. The scanning signal 21 is applied to an odd-numbered scanning line of the liquid crystal panel during a certain two vertical synchronizing signals 20. It can be seen from FIG. 2 that the two vertical synchronizing signals 20 are applied to the even-numbered scanning lines of the liquid crystal panel.

FIG. 3 is a timing chart in the case where EDTV display is performed by the driving method of the present invention, and two scanning lines are simultaneously driven.

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

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

That is, when the first row of the scanning line corresponding to the left X-side driver is selected in a certain field, the second row of the scanning line corresponding to the right X-side driver is simultaneously selected. So that

It is assumed that one set of two scanning lines is
.. 999, 1000 lines are selected and driven simultaneously to scan two scanning lines constituting one screen in one field, thereby realizing a non-interlace system. .

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

In the drawing, Gn indicates a scanning signal on the n-th row of the liquid crystal panel, and the scanning signal 21 is applied to all the scanning lines of the liquid crystal panel between two vertical synchronizing signals 20. 3 shows.

FIG. 4 is a diagram showing a video signal switching process in the method of driving a liquid crystal display device according to the present invention.

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

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

Further, the timing signal is supplied to the X-side driver.
The signal is applied to a selection circuit 24 and converted into an interface signal 25 for alternately selecting odd and even scanning lines and a non-interlace signal 26 for simultaneously selecting two scanning lines.

[0054]

As described above, according to the present invention,
A liquid crystal display device having one HDTV equivalent scanning line
Both DTV and EDTV can be displayed.

[Brief description of the drawings]

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

FIG. 2 is a timing chart of an interface-type drive signal of the present invention.

FIG. 3 is a timing chart of a driving signal of a non-interlace type according to the present invention.

FIG. 4 is a diagram illustrating a video signal switching process 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 interface system.

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]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal panel 2 X side driver 3 X side driver 4 Scan 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 Reference Signs List 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 Interface signal 26 Non-interlace − Signal

Claims (1)

(57) [Claims] 1. A driving method for a liquid crystal display device having at least an X-side scanning line and a Y-side signal line corresponding to at least a full line of a high-definition signal. X-side driver
The two different systems of X-side drivers are interface driven one field at a time to perform HDTV display, and the two different systems of X-side drivers are driven by two adjacent scanning lines. And a EDTV display by simultaneously driving two lines constituting one screen in one field.