JPH055114B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for driving a color liquid crystal image display device using a transmissive active matrix liquid crystal panel, and an object of the present invention is to provide a method for driving a color liquid crystal image display device that uses a transmissive active matrix liquid crystal panel, and which enables good multicolor image display. do.

FIG. 1 is a diagram for explaining a method of driving a conventional black-and-white liquid crystal image display device. In FIG. 1, the RF signal received by antenna 101 is
The signal is returned to an intermediate frequency signal in the tuner 102, and then demodulated into an image signal 108 by passing through an intermediate frequency signal processing circuit (hereinafter abbreviated as IF circuit) 103. Timing control circuit 104
is the timing signal 109,1 from the image signal 108
10 are extracted and each data line drive circuit 10 is extracted.
5. Supply to the scanning line drive circuit 106. Shift register 111 and analog switches 112, 11
Data line drive circuit 10 consisting of 3, . . . 117
5 samples and holds the image signal 108 transmitted by the video line 130 and sends it to the data line 11.
8, 119, . . . 122.

The scanning line drive circuit 106 drives the scanning lines 124, 125, . . . 129 at the period of the horizontal synchronization signal.
131, 132 etc. are thin film transistors, MIM
A pixel is composed of a switching element such as a metal insulatar (metal insulatar metal) element and a liquid crystal. pixel 13
1, 132, etc. are displayed in halftones according to the level of the image signal. In this case, the image signal 108 is a luminance signal that gives the luminance of the pixel, and the driving method shown in FIG. 1 cannot drive a color liquid crystal display device.

The present invention corrects the above-mentioned drawbacks of conventional methods for driving a liquid crystal image display device, and provides a method for driving a liquid crystal image display device that enables good multicolor image display.

Hereinafter, the present invention will be explained in detail based on Examples.

FIG. 2 is a diagram showing a first embodiment of the present invention. In the figure, the same parts as those in FIG. 1 are given the same reference numerals. In FIG. 2, similar to FIG. 1, the RF signal received by the antenna 101 is
The signal is returned to an intermediate frequency signal in the tuner 102, and is further demodulated into an image signal 108 by passing through an IF circuit 103. The timing control circuit 104 extracts timing signals 109 and 110 from the image signal 108 and supplies them to the data line drive circuit 203 and the scanning line drive circuit 106, respectively. On the other hand, the color processing circuit 201 processes 3 from the image signal 108.
Different types of color signals 231, 232, and 233 are separated and extracted. In this embodiment, three color signals 23
Three primary color signals of red, green, and blue are used for signals 1, 232, and 233, respectively, but the gist of the present invention is to
There is no difference even if a color signal other than the primary color signal is used, and the number of color signals may be any number of colors as long as it is three or more colors. The data line drive circuit 203 includes a shift register 204, three video lines 211, 2
12, 213, and analog switch 205,
Consisting of 206...210, video line 21
The color signals 231, 232, 233 transmitted by the data lines 118, 119, . . .
Apply to 3. On the other hand, the scanning line drive circuit 106
Scanning lines 124, 125, . . . at the period of the horizontal synchronization signal
...129 is driven. 214, 215...230
A pixel is composed of a switching element such as a thin film transistor or an MIM element, a liquid crystal, and a color filter, and an active matrix liquid crystal panel 202 is formed by a collection of a plurality of pixels. Second
In the illustrated embodiment, 231 is a red primary color signal, which is sampled and held by analog switches 205, 208, .
1, ... is supplied. Similarly, green primary color signal 2
32 is sampled and held by analog switches 206, 209, . . . and connected to data lines 119, 12.
2, . . . The blue primary color signal 233 is sampled and held by analog switches 207 . . . and supplied to data lines 120 . Figure 3 shows the relationship between the red primary color signal VSR, the green primary color signal VSG, and the blue primary color signal VSB and the timing at which these primary color signals are sampled and held by the analog switch in the data line drive circuit. . In the same figure, TR is the red primary color signal VSR,
TG is the green primary color signal VSG, TB is the blue primary color signal
This is the timing when VSB is sampled and held, and the cycle is TR→TG→TB. Note that 1H represents one horizontal scanning period, that is, one period of the horizontal synchronizing signal. ) In the embodiments shown in FIGS. 2 and 3, the color scheme of the color filters used is striped as shown in FIG. In the figure, R, G, and B mean red, green, and blue, respectively.

By using the above driving method,
Multicolor image display using liquid crystal will become a reality. Furthermore, according to the above-described driving method, since the writing time of the image signal to the data line can be set to an arbitrary length without lowering the resolution, the time constant t of the data line can be set to an arbitrary length.
This makes it possible to drive large active matrix liquid crystal panels.

FIGS. 5 to 10 are diagrams for explaining a second embodiment of the present invention. Compared to the color filter with a striped color scheme as shown in Figure 4,
A color filter having a periodic mosaic-like color scheme as shown in FIGS. 6 and 7 has the effect of increasing the resolution of the screen. A second embodiment of the present invention will be described below, taking as an example a case where an active matrix liquid crystal panel is formed using the color filters shown in FIG. FIG. 8 is a block diagram showing the driving method of this embodiment. In the figure, the same parts as those in FIG. 2 are given the same reference numerals. In Figure 8,
The process until the RF signal received by the antenna 101 is demodulated into the image signal 108 by the tuner 102 and the IF circuit 103 is exactly the same as in FIG. The image signal 108 is divided into a red primary color signal 231, a green primary color signal 232, and a blue primary color signal 233 by the color processing circuit 201. Primary color signal 23
1, 232, and 233 are further switched every horizontal scanning period (1H) in the multiplex circuit 802 by a control signal 806 output from the timing control circuit 801. This situation is shown in FIG. For example, video line 803
The signal VS1 transmitted by VSR→VSG→VSB→VSR at timing TH of 1H period
→VSG→...The signal is switched to the same primary color signal in 3H cycles. (however,
(VSR, VSG, and VSB are primary color signals of red, green, and blue, respectively) If the switching timing TH is set to exist in a period 901 in which no display is displayed on the liquid crystal display device, that is, one horizontal blanking period, Even better color images can be obtained. video line 8
The color signal VS1 transmitted by 03, the color signal VS2 transmitted by video line 804, and the color signal VS3 transmitted by video line 805 are as follows.
As shown in FIG. 10, each signal is sampled and held by an analog switch in the data line drive circuit. That is, the color signal VS1 is applied to the analog switches 205, 208,
Sampled and held by ..., data line 1
18, 121, . . . Similarly, the color signal VS2 is sampled and held by the analog switches 206, 209, . . . at timing T2, and is supplied to the data lines 119, 122, . Further, the color signal VS3 is sampled and held by the analog switches 207, . . . at the timing of T3, and the data lines 120, .
is supplied to

The present embodiment is otherwise the same as the first embodiment. This results in higher resolution, more natural,
Color image display using a liquid crystal panel is realized.

As described above, according to the present invention, the combination of the three primary color signals to be transmitted and the video line is periodically switched, that is, the three primary colors (R, G, B) applied to one video line are changed over time. By switching to , it is possible to connect not only one color but three color filters to one data line. For this reason, the color filter arrangement is not limited to a stripe arrangement.
Various variations such as mosaic arrangement and delta arrangement are possible. This makes it possible to realize a color liquid crystal display device with even higher resolution.

Furthermore, since the above-mentioned switching timing is set within one horizontal blanking period, flickering and the like due to switching do not occur, and good color display is possible.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining a conventional driving method of a liquid crystal image display device. FIG. 2, FIG. 3, and FIG. 4 are diagrams for explaining the first embodiment of the present invention.
Figure 5, Figure 6, Figure 7, Figure 8, Figure 9, Figure 1
FIG. 0 is a diagram for explaining a second embodiment of the present invention. 201...Color processing circuit, 202...Active matrix panel, 203...Data line drive circuit.

Claims (1)

[Claims] 1. Three primary color signals separated from an image signal are sent to a plurality of video lines through a plurality of color filters arranged corresponding to a plurality of pixels arranged in a matrix in a color liquid crystal image display device. In the method for driving a color liquid crystal image display device, the combination of the three primary color signals and the plurality of video lines is switched in synchronization with one horizontal scan of the image signal, and the switching time point is set as the image signal. A method of driving a color liquid crystal image display device, characterized in that setting is performed within one horizontal blanking period.