JPS6392928A - Color liquid crystal display using active double matrix - Google Patents

Abstract

PURPOSE:To reduce the load of a line memory circuit by providing two kinds of data lines for specifying a pair of upper and lower liquid crystal components on a matrix and using gate lines in common to form double matrix constitution. CONSTITUTION:A panel has the double matrix constitution consisting of odd data lines 11, even data lines 12 and gate lines 13. When a gate line 13 to be a scanning signal line is selected, a thin film transistor (TR) 16 is turned on and odd and even data corresponding to a pair of upper and lower liquid crystal picture elements are simultaneously written in the liquid crystal picture elements R1-1, G1-1 adjacent to the gate line 13 through the data lines 11, 12. In case of reproducing a TV picture using about 260 scanning lines to a high quality picture having twice the display lines of the TV picture, time capable of selecting each data line is 52.7musec/n (n is the number of liquid crystal elements in one scanning line), so that the time capable of selecting one liquid crystal picture element can be increased and the device can be used under a state increasing its charging rate. Consequently, it is unnecessary to store an input signal in a line memory.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a so-called active matrix color liquid crystal display device that drives liquid crystal using active elements such as thin film transistors (hereinafter abbreviated as TPT) and diode rings. .

2. Description of the Related Art Here, a description will be given using a three-terminal active element of TPT. The active matrix color liquid crystal display device that uses conventional TPT active elements to drive the liquid crystal is the fifth type.
It has the configuration shown in the figure.

For a particular data line 6, the cells are Pi, ~Pio
The TPT4 is connected to
N, the display content is written from the data line 6 to the liquid crystal pixel 8, and then the TPT 4 is turned off and the written data is held until the next selection. Now, if we consider a TV screen display using about 260 scanning lines using polysilicon with a time constant of several n5ec for TFT4, the selection time of one scanning line is approximately 63.6μ860, field The period is 16.7 m5ec. In other words, when n liquid crystal pixels are lined up on one scanning line, data is written to each pixel in 52.7 μsea/n of one scanning period, and the data is retained for 16.7 m515c. Become. This scanning method is a point-sequential driving method in which the image input signal 1 is sequentially selected from the shift register 2 to drive the TPT 4 of each cell via the switching transistor 3 (Japanese Unexamined Patent Publication No. 158691/1982). and,
Red (R), green (G) corresponding to multiple color image input signals
), blue CB) are arranged as shown in FIG.

According to the conventional configuration, when it is desired to reproduce an image with twice the number of display lines as the number of scanning lines in a field (hereinafter referred to as a high-quality image), the number of samplings of the image input signal 1 is doubled,
Image input signal 1 is sampled as shown in FIG.

Next, in order to send out this sampled data and select a pair of upper and lower liquid crystal pixels in the matrix corresponding to two scanning lines, it is necessary to send two gate lines for each data line.
Use books. Since the gate lines are selected in order from top to bottom, data line 6 in FIG. 5 is common to R1-1 and G.
In order to write an image input signal to one set of liquid crystal pixels +-+, the image input signal to be written to the cell connected to the gate line G, and the image input signal written to the cell connected to the gate line G2 are separated into lines. Image input signals to a pair of upper and lower liquid crystal pixels are stored in the memory 5, and are taken out from the memory one by one and sent to each liquid crystal pixel from each data line. In order to select two gate lines within one scanning period for display using the dot sequential driving method, the time applied to the liquid crystal pixels is 31.8 μB, which is half of the previous selection time T.
This is done within 0/n.

Problems to be Solved by the Invention In such a conventional configuration, when reproducing the above-mentioned high-quality image, a sampled image input signal is used to perform point-sequential driving to specify a pair of upper and lower liquid crystal pixels. Because the matrix configuration is such that two upper and lower gate lines correspond to one data line, the sampled R, G, and B image input signals are directly input as shown in Figure 6. At the same time, liquid crystal pixel R1-1 corresponding to FIG. 5! G1-11
0+-21L-+ +... cannot be applied to the two types of line memories Od and Ev in FIG. 6 corresponding to the gate lines G and G2, respectively. There is a problem in that after all image input signals sampled during one running period have been stored in the line memory, each gate line must be selected and sequentially retrieved from the line memory and displayed. Ta. Also, because the time t when the image input signal is written into the line memory and the time t2 when it is read out from the line memory and written to the liquid crystal pixel are different, the capacity of the line memory is limited to two input horizontal omnivorous signals. It was necessary.

The present invention is intended to solve these problems, and aims to enable point-sequential driving without the need to store image input signals in a line memory.

Means for solving the problems and the technical means of the present invention for solving the above problems are as follows: A pair of upper and lower liquid crystal pixels in a matrix corresponding to one sampling signal during one scanning period; An odd data line corresponding to the upper liquid crystal pixel of the pair of liquid crystal pixels, an even data line corresponding to the lower liquid crystal pixel of the pair of liquid crystal pixels, and a scanning signal line of the upper and lower pair of liquid crystal pixels. It has a double matrix configuration with a common gate line, and a transistor that performs a switching operation for each output of the shift register transfers the image input signal to the above pair using the odd data line and the even data line. The voltage is applied to the liquid crystal pixels at the same time.

Effect With this configuration, the image input signal on one scanning line is divided into two types of signals, one for the odd data line and the other for the even data line, and by using the output of the shift register described above, Since the corresponding image input signal and the image input signal corresponding to the even data line can be sampled simultaneously, there is no need to store the image input signal in the line memory.
In this way, point-sequential driving is possible.

Furthermore, according to the present invention, the gate lines corresponding to the pair of upper and lower liquid crystal pixels are shared as one gate line instead of two in the conventional case, so the total number of gate lines in the entire device can be reduced to half of the conventional one. Therefore, the gate line selection time can be increased, and the charging rate of the liquid crystal pixels can also be increased.

Example An embodiment of the present invention will be described below.

Figure 1 is a panel configuration diagram of an active dual matrix color liquid crystal display device, where 9 is an image input signal, 10 is a liquid crystal pixel, 11 is an odd data line, 12 is an even data line, and 13 is a panel configuration diagram of an active dual matrix color liquid crystal display device.
is the gate line, 14 is the odd data line 11 and the even data line 1
A driver 15 drives the gate line 13, and a gate line selection circuit 15 sequentially selects the gate lines 13 from top to bottom. This channel has a double matrix configuration with odd data lines 11, even data lines 12, and gate lines 13.

FIG. 2 shows the drive circuit of this display device.

In this example, it is assumed that polysilicon with a time constant of several n5ec is used for the TFT 16, the color cells are arranged at positions corresponding to FIG. 5, and each pixel is driven dot-sequentially.

The operating principle is that the image signal period used for display within one horizontal synchronization period is determined by the number n of liquid crystal pixels in the horizontal direction of the liquid crystal display device (
A shift register 1 whose clock is a signal with a period divided by n = several hundred or more) and which receives a horizontal synchronization signal 19 as an input.
For each output of 7, the image input signal 9 corresponding to each liquid crystal pixel is sampled by a switching transistor that performs a switching operation. As shown in FIG. 3, the Od and Ev data sampled to correspond to a pair of upper and lower liquid crystal pixels can be transmitted to the TFTl 6 by selecting the gate line 13, which is the scanning signal line in FIG.
N, the data is written to both liquid crystal pixels R1-4 and 01-1 adjacent to the gate line 13 at once using the odd data line 11 and the even data line 12. As mentioned above, sampling data can be written to a pair of upper and lower liquid crystal pixels at once, so when reproducing a TV screen that uses about 260 scanning lines into a high-quality image with twice as many display lines as mentioned above, , the time during which each data line can be selected is 5
2.7μS5C/n, compared to 31.8μ of the conventional method.
This is approximately 1.7 times that of sea/n, which increases the time during which one liquid crystal pixel can be selected, and allows use with a higher charging rate.

Further, by arranging driver circuits consisting of a shift register 17 and a switching transistor 18 for driving the odd data lines 11 and even data lines 12 above and below the liquid crystal display portion, wiring is easy.

Next, another embodiment will be explained with reference to FIG.

In this embodiment, amorphous silicon having a time constant of several μsec is used for the TFT 16. Due to the problem of the TPT160 time constant, a line-sequential drive method is adopted as a drive method for the active elements of the display device. The drive circuit in Fig. 4 is
In addition to Figure 2, a 2o capacitor is included. Fourth
The operating principle of the diagram is as follows. As in the previous embodiment, the data sampled from the image input signal 9 using the shift register 17 and the switching transistor 18 is temporarily stored in the capacitor 20, which is a buffer memory. After all the image input signals on one scanning line are sampled, by selecting the gate line 13, all 'ry'ri 6 of each cell are turned ON, and the odd data line 11 and the even data line 12 are turned on. Using gate line 13
It is possible to simultaneously apply the voltage to all liquid crystal pixels 1o adjacent to the same.

The output selection time of this gate line is approximately 10 times the retrace time (T3 in Fig. 3) from the end of sampling of the image input signal used to display one scanning line to the start of sampling of the next scanning line. .8 μsec. Here, the minimum value of the equivalent resistance value when the amorphous silicon is in the ON state is 1 MΩ, the equivalent capacitance of the liquid crystal pixel 1o is 1 pF, and the time constant is set to 1 μ$θC. In other words, the time constant is 1μs
In order to write data to the ec liquid crystal pixels, it is sufficient if the selection time of each gate line is about 10μ5e50.

However, if line sequential driving is to be performed with the conventional configuration, two gate lines must be selected during the retrace time T in FIG. 6, so the selection time for one gate line is T,
/2 of 5.4 μsec L, and the ON resistance of the above amorphous silicon (i) is 2 to 3 MΩ,
The time constant becomes large and the liquid crystal pixels cannot be sufficiently charged.

Therefore, in this embodiment, even in line-sequential driving, it is possible to sufficiently display the image data of the liquid crystal pixels 10 by simply adding the capacitor 20, which is a buffer memory that holds data until the retrace time.

Effects of the Invention As described above, according to the present invention, when reproducing a high-quality image using a color image input signal, two types of data lines are provided for specifying a pair of upper and lower liquid crystal pixels on a matrix. By adopting a double matrix configuration with a common gate line, the number of line memory circuits is reduced, and by separating the driver circuits for each data line into upper and lower sections, the driver circuit for color liquid crystal display devices is simplified. In addition, since the time for selecting the gate line is increased, the charging rate of the liquid crystal pixels is increased, and a clearer, high-quality image can be reproduced.

[Brief explanation of the drawing]

FIG. 1 is a panel configuration diagram of an active dual matrix color liquid crystal display device of the present invention, and FIG. 2 is a circuit diagram of a driving circuit of a liquid crystal display device for dot-sequential driving of liquid crystal pixels according to an embodiment of the present invention. FIG. 3 is an explanatory diagram of its operation, FIG. 4 is a circuit diagram of a drive circuit for line-sequential driving according to another embodiment of the present invention, and FIG. 5 is a drive circuit of a conventional active matrix color liquid crystal display device. The circuit diagram of FIG. 6 is an explanatory diagram of its operation. 9... Image input signal, 1o... Liquid crystal pixel, 11... Odd data line, 12...
Even data line, 13... Gate line, 14...
...Driver, 17...Shift register,
18...Switching transistor. Name of agent: Patent attorney Toshio Nakao and one other person?
-1 Pixel inlay 1 No. 10 - Liquid crystal pixel n-'j - 12 - Even data line 13 - Gate line 14 - Driver Figure 1 Figure 2 Figure 3 Br-z Eh-s No. 4 Figure 5 Figure 6 g7-z f3r-3

Claims (3)

[Claims] (1) A plurality of color image input signals are used as image input signals, and a pair of upper and lower liquid crystal pixels in a matrix corresponding to one sampling signal during one scanning period, and an upper A gate line consisting of an odd data line corresponding to the liquid crystal pixel, an even data line corresponding to the lower liquid crystal pixel of the pair of liquid crystal pixels, and a gate line that shares the scanning signal line of the upper and lower pair of liquid crystal pixels. An active double matrix color liquid crystal display device having a double matrix configuration and reproducing an image of twice the number of display lines in a field of the image input signal. (2) A shift register which receives a horizontal synchronization signal as an input and whose clock is a signal having a period obtained by dividing the image signal period used for display by the number of horizontal liquid crystal pixels within one horizontal synchronization period, and each of this shift register. Claim 1, characterized in that an image input signal is simultaneously applied to a pair of upper and lower liquid crystal pixels using an odd-numbered data line and an even-numbered data line by a transistor that performs a switching operation on the output.
The active dual matrix color liquid crystal display device described in Section 1. (3) The active device according to claim 2, characterized in that a driver circuit consisting of a shift register and a transistor for driving odd-numbered data lines and even-numbered data lines is arranged separately in the upper and lower parts of the display part. Dual matrix color liquid crystal display.