JPH05103285A - Liquid display device and its driving method - Google Patents

Abstract

PURPOSE:To display both a high-vision image and an NTSC image by dividing a liquid crystal pannel into plural blocks and displaying plural channels on the same screen when the NTSC or EDTV image is displayed. CONSTITUTION:A liquid display device is constituted of data drivers 2 and 3 supplying a video signal to the liquid crystal pannel 1 which has the aspect ratio of an effective display part by 16:9, about one thousand scanning signal lines and video signal lines within the range of 1400-1920 lines, gate drivers 4 and 5 controlling TET(thin film transistor) inside the liquid crystal pannel 1, a video signal processing circuit 6 for high-definition or NTCS and a timing signal generating circuit 7 controlling the drivers. When the high-vision image is displayed, the image is displayed in the whole areas of the pannel 1 of the liquid crystal display device. When the NTSC image is displayed, switching control is executed in order to display the image in a part of the areas or the whole areas of the pannel 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-definition liquid crystal display device for displaying images of the current NTSC and EDTV systems and a driving method thereof.

[0002]

2. Description of the Related Art Hi-vision broadcasting is based on broadcasting satellite (BS-
3b) launch extended broadcast time, 1997
Full-scale broadcasting is scheduled for the year.

Under such circumstances, the development and commercialization of related equipment such as a high-definition television receiver is actively being carried out.

As a high-definition display device, a projection TV using a CRT, as well as a direct-view CRT whose standard is standardized in 32 inches and 36 inches, is used.
Also, projection TVs using liquid crystal panels have been commercialized. Research on high-definition display using flat panel display devices such as plasma displays is also underway.

However, all the display devices are dedicated to high-definition display and cannot display the current NTSC broadcast.

On the other hand, high-definition broadcasting is based on the current NTSC.
A decoder (down converter), which is a related device, has been developed for displaying on a display device for use, and it is possible to enjoy high-definition broadcasting on a CRT currently in each home. However, the original purpose of high-definition display is to deviate from the original definition of high-definition and sharpness, and a powerful and realistic image.

[0007] In the future, when high-definition video enters the home due to the enhancement of high-definition broadcasting and the price reduction / spreading of related equipment, at present, TVs for NTSC and high-definition are required, respectively. Problems such as price will occur.

That is, in the future, instead of displaying a high-definition signal on a display device for NTSC using a down converter, a high-definition display device for enjoying high-definition, realistic and powerful images, which is the original purpose of high-definition television, will be provided. It is considered that it is required to display the current NTSC video.

Further, it is desired that the display device is not a display device using a CRT, which is heavy in terms of weight, but is lightweight and thin.

Now, the difference between the NTSC standard and the high-definition standard will be described.

The major differences between the two standards are the number of vertical scanning lines and the aspect ratio of the screen (the aspect ratio of the television screen).

The number of vertical scanning lines, the number of effective scanning lines, and the aspect ratio of the NTSC standard and the high-definition standard will be shown below.

Aspect ratio: NTSC = 4: 3, HDTV = 1
6: 9 ・ Number of vertical scanning lines: NTSC = 525 lines, HD =
1125 lines-Number of effective scanning lines: NTSC = 485 lines, HDTV =
1035 However, in the display device conforming to the high-definition standard, NT
Displaying SC images has the following problems.

Regarding the number of vertical scanning lines, the NTSC standard is about half that of the high-definition standard. Therefore, when an NTSC image is displayed on a display device of the high-definition standard, it is displayed only in an approximately 1/2 area in the vertical direction. Nothing is displayed in the remaining half of the area.

Further, due to the difference in the aspect ratio of the screen,
When an NTSC broadcast is displayed in the entire effective display area with an aspect ratio of 16: 9 according to the high-definition standard, the image becomes long in the horizontal direction.

As described above, in order to display a high-definition image on a high-definition standard display device, it is necessary to solve the above problems.

[0017]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the related art, and a liquid crystal which displays different types of images such as high-definition images and NTSC / EDTV images on the same display device. A display device and a driving method thereof are provided.

[0018]

A method of driving a liquid crystal display device according to the present invention includes a matrix display panel having a plurality of scanning signal lines and a plurality of image signal lines corresponding to the high definition standard, and a scanning signal line of the panel. And a scanning signal drive circuit connected to the panel, and an image signal drive circuit connected to the image signal line of the panel.
In a method of driving a liquid crystal display device capable of displaying both images, in the case of displaying a high-definition image, the same scanning signal is simultaneously supplied to each scanning signal line group consisting of the plurality of adjacent scanning signal lines. Is.

Further, the liquid crystal display device of the present invention includes a matrix display panel having a plurality of scanning signal lines and a plurality of image signal lines corresponding to the high definition standard, and a scanning signal drive connected to the scanning signal lines of the panel. Circuit, and a video signal drive circuit connected to the video signal line of the panel, for high-definition video and current NTSC video or EDTV
In a liquid crystal display device capable of displaying, a high-definition image is displayed in the entire area of the panel, and an NTSC or EDTV image is displayed by dividing the panel into a plurality of blocks. , It is possible to display a plurality of channels on the same screen.

Furthermore, the liquid crystal display device of the present invention includes a matrix display panel having a plurality of scanning signal lines and a plurality of image signal lines corresponding to the high-definition standard, and a scanning signal connected to the scanning signal lines of the panel. A drive circuit and a video signal drive circuit connected to the video signal line of the panel are provided, and the high-definition video and the current NTSC video or E
It is possible to switch the display between the DTV and the display.

[0021]

According to the liquid crystal display device of the present invention, when a high-definition image is displayed, the image is displayed on the entire area of the panel of the liquid crystal display device, while when an NTSC image is displayed, the panel is displayed. By controlling the switching so as to display in a part or the whole area of the same, it is possible to display different types of images such as high-definition images and NTSC images on the same liquid crystal display device.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the structure of a video display device of the present invention.

The liquid crystal display device shown in the figure complies with the high-definition standard, and the aspect ratio of the effective display part is 16: 9, about 1000 scanning signal lines and 1400 to 1920 video signal lines are provided.
Data drivers 2 and 3 for supplying a video signal to the liquid crystal panel 1 which is a book, gate drivers 4 and 5 for controlling TFTs (thin film transistors) in the liquid crystal panel 1, a high-definition or NTSC video signal processing circuit 6, and a driver And a timing signal generation circuit 7 for controlling.

The operation of each block when a high-definition image is displayed on the liquid crystal display device shown in FIG.

Since high-definition broadcasting uses 2: 1 interlaced scanning, 4 of the gate drivers 4 and 5 in the odd-numbered field sequentially shifts every horizontal scanning period, but 5 does not. In the even field, 5
Similarly, only 4 shifts every horizontal scanning period, but 4 does not.

The data drivers 2 and 3 have the following <
The video signal is sampled and held by the output pulse of the shift register that operates at the frequency f calculated by Equation 1>, and the video data is supplied to the liquid crystal panel in synchronization with the shift operation of the gate driver.

[0027]

[Equation 1]

The video signal processing circuit 6 amplifies a high-definition video signal and performs an AC inversion process necessary for driving the liquid crystal panel.

FIG. 2 shows a timing chart of each signal supplied to the liquid crystal display device.

Here, the timing signal generation circuit 7 starts signals STV1 and STV2 for starting the shift operation of the left and right gate drivers and shift clocks CKV1 and CK.
V2 and V2 are generated alternately for each field. Further, it also generates the clock signal and the start signal of the data driver having the operating frequency obtained by the above-mentioned <Formula 1>.

FIG. 3 shows a display area of a high-definition image in the liquid crystal display device of the present invention.

In FIG. 9A, the number of pixels in the horizontal direction is 1920 dots (length 16
0 cm), the number of pixels in the vertical direction is 1024 dots (length 90
cm) shows the effective display area of the display panel,
FIG. 3B shows a display area when a high-definition broadcast is displayed.

FIG. 4 shows a display area in the case of NTSC (including EDTV) broadcasting.

FIG. 3A shows an example in which two adjacent scanning signal lines are driven in pairs, and an image is displayed in the central portion of the display area of FIG. 3A. That is, using only the number of effective scanning lines of NTSC 485 × 2 = 970 lines,
27 unused lines are provided above and below the display surface, and an image is displayed in an area having an aspect ratio of 4: 3 in the horizontal direction according to the size of the scanning line 970 lines.

The left and right non-display areas are the difference in aspect ratio between the NTSC standard and the high definition standard, that is,
From the difference between 4: 3 (12: 9) and 16: 9, 1 in the left-right direction
Each / 8 may be provided as an unused area that is not displayed on the left and right of the display area.

The horizontal image display dimension and the left and right unused area dimensions are calculated by the following equations.

90 cm × (970/1024) × (4/3) = 113.67 cm (160 cm-113.67 cm) /2=23.165 cm NT having an aspect ratio of 4: 3 is provided by providing a region of this width.
SC / EDTV video can be obtained. That is, the NTSC image is displayed in the center of the screen, and the non-display areas are provided on the left and right of the display. This unused area may be displayed with an arbitrary background color such as black display.

Next, an example in which the NTSC / EDTV image is overscan-displayed using the entire area of the display panel shown in FIG. 4B will be described.

In the horizontal direction, 1920 dots (1
60 cm) and using one vertical direction,
Since the aspect ratio of NTSC / EDTV is 4: 3, the display size is 160 cm × 3/4 = 120 cm, and 364 of the 485 effective scanning lines of NTSC / EDTV (485 × 90 cm / 120 cm) are displayed on the display panel. If it is displayed in the entire area of, the NTSC / EDTV image can be displayed.

On the other hand, in the case of performing NTSC / EDTV display by using all the 1024 dots in the vertical direction, if the same scan signal is supplied to three adjacent scan signal lines and overscan is performed, 341 scans are performed. It can be displayed as a line.

FIG. 4 (c) uses the entire area of the display panel to display NTSC / EDTV broadcast images of four different channels, such as commercial companies A, B, C and D. Here is an example. The number of scanning lines for 1-channel display is 48
Since it is composed of five lines, it is possible to construct a two-screen display in the vertical direction. The horizontal direction is set according to the aspect ratio of 4: 3.

The multi-channel display for displaying images of a plurality of channels on the same screen is not limited to four channels.

FIG. 5 is an ED in the case of driving FIG. 4 (a).
The timing chart in a TV system is shown.

As shown in FIG. 5, the first 27 in FIG.
In order to set the line as an unused area, the vertical start signal STV is set by 27 horizontal scanning periods (27 Hs) earlier than the start of the effective scanning line.

That is, the start signal STV1 of the left odd row driver is 14 Hs before the effective scanning line, and the start signal STV2 of the right even row driver is 1 before the effective scanning line.
By generating at 3 Hs, the first image is displayed on the 28th and 29th lines of the display panel.

On the other hand, in the horizontal direction, the effective display period is about 52 μs.
Approximately 1364 dots (113.67 cm x 19)
20/160 cm) may be sampled. In this case, the frequency of the shift clocks of the data drivers arranged above and below is basically 13 MHz according to the following equation.

1364 dots / 52 μs / 2≈13 MHz FIG. 6A is a timing chart showing the driving example of FIG. 4B.

In this case, contrary to the above-mentioned FIG. 4A, overscan display is performed. The first 72 lines of video data are not displayed on the display,
Since the same scanning signal is supplied to the lines, the scanning signal lines 1, 2, 3 (G1, G2, G3 in the drawing) of the display panel may be turned on at the 73rd line after the start of effective scanning. And
G4, G5, and G6 should be sequentially shifted to the 74th line, and G7, G8, and G9 should be sequentially shifted to the 75th line. The 76th and subsequent lines are similarly shifted.

When the same scanning signal is supplied to the three adjacent lines, the gate driver needs a latch function and an output control function, but the number of lines supplying the same scanning signal is three lines. Without limitation, it is possible to enlarge and display 4 lines, 6 lines, or the like. In that case, the display period in the horizontal direction may be changed according to the number of vertical display lines and the aspect ratio.

FIG. 6B shows a display period in the horizontal direction. That is, 341 × in the area of 90 cm in the vertical direction.
The display period in the horizontal direction corresponding to the display of 3 = 1024 dots is 48.8 μs, and the shift clock is 19.7M.
It shows that it becomes Hz. Here, a typical operation of the above-mentioned latch function will be described. For example, considering interlaced scanning with one side arrangement of the gate driver, the output of the gate driver needs to be a signal for each output.
In this case, a latch circuit is needed. That is, the shift register is sequentially shifted and its output is set to 1 by the latch circuit.
It will be converted for each book.

The timing chart thereof is shown in FIG. In the figure, the latch circuit is in the through mode when LAT is High and in the latch mode when LAT = Low.

The input of the latch circuit is the output signal of the shift register circuit. When LAT is High, the latch output outputs the output signal of the shift register through,
When AT is Low, the output is held. That is, by supplying the LAT signal at a cycle twice that of the shift clock (CKV), it is possible to output a signal shifted for each line.

Even when the three lines are simultaneously driven by arranging both sides of the gate driver, the control method is somewhat complicated, but basically the above-mentioned latch operation is required.

As described above, with the liquid crystal display device capable of switching the display between the high-definition video and the current NTSC video or EDTV, the original definition of high-definition display is high definition and sharpness, and it is more realistic. A powerful image can be obtained, and at the same time, the current NTSC video can be displayed on the same display device without using a new display device. Furthermore, since it is a lightweight and thin liquid crystal display device, it is very effective in terms of installation space and weight.

[0055]

According to the present invention, high-definition and NTSC / NTSC / TV can be displayed on a single display device without impairing the original high-definition, high-definition, realistic image.
It is possible to display images of different systems called EDTV, and even if high-definition television spreads in each home in the future, not only a plurality of display devices are required but also television display of each system becomes possible. It becomes a lightweight and thin display device.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a liquid crystal display device targeted by the present invention.

FIG. 2 is a timing chart for high-definition display on a liquid crystal display device.

FIG. 3 is a diagram showing an image display area in each mode.

FIG. 4 is a timing chart in EDTV mode.

FIG. 5 is a timing chart showing a driving example.

FIG. 6 is a timing chart showing a driving example.

FIG. 7 is a timing chart illustrating a latch function.

[Explanation of symbols]

 1 liquid crystal panel 2 data driver 3 data driver 4 gate driver 5 gate driver 6 video signal processing circuit 7 timing signal generation circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H04N 7/01 J 9070-5C

Claims (3)

[Claims] 1. A matrix display panel having a plurality of scanning signal lines and a plurality of image signal lines corresponding to a high-definition standard, a scanning signal drive circuit connected to the scanning signal lines of the panel, and an image signal of the panel. Equipped with image signal drive circuit connected to the line, high-definition video and current NTS
In a method of driving a liquid crystal display device capable of displaying both C images, when displaying a high-definition image, the same scanning signal is simultaneously supplied to each scanning signal line group consisting of the plurality of adjacent scanning signal lines. A method for driving a liquid crystal display device, comprising: 2. A matrix display panel having a plurality of scanning signal lines and a plurality of image signal lines corresponding to the high definition standard, a scanning signal drive circuit connected to the scanning signal lines of the panel, and a video signal of the panel. Equipped with a video signal drive circuit connected to the line, high-definition video and current NT
In a liquid crystal display device capable of displaying SC video or EDTV, when high-definition video is displayed, it is displayed in the entire area of the panel, and the NTSC or EDTV is displayed.
A liquid crystal display device characterized in that, when displaying an image, the panel is divided into a plurality of blocks and a plurality of channels can be displayed on the same screen. 3. A matrix display panel having a plurality of scanning signal lines and a plurality of image signal lines corresponding to the high-definition standard, a scanning signal drive circuit connected to the scanning signal lines of the panel, and a video signal of the panel. Equipped with a video signal drive circuit connected to the line, high-definition video and current NT
A liquid crystal display device capable of switching display between SC video and EDTV.