JPS63290085A - Liquid crystal video display - Google Patents

Abstract

PURPOSE:To set a picture to be clearly viewed by dividing vertical lines into lines addressing picture elements with odd-numbered lateral lines and lines addressing the picture elements with even-numbered lateral lines and extracting them. CONSTITUTION:Picture elements 17 and 18 connected with a vertical line 11 cross with even-numbered lateral lines 13 and 15. Picture elements 19 and 110 connected with the other vertical line 12 cross with even-numbered lateral lines 14 and 16. With dividing the vertical line 11 connected with the picture elements 17 and 18 which cross with the odd-numbered lateral lines 13 and 15, and the vertical line 12 connected with the picture elements 19 and 110 which cross with the even-numbered lateral lines 14 and 16, a panel having the lateral lines more than 400, for example, can be driven by skipped scanning even if a field memory is not given in terms of circuit. Since the frequency of even number- multiplied field is large, the flicker of a screen can be eliminated. Thus, the picture can clearly be displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to pixel arrays and applied signal waveforms for liquid crystal video displays.

[Conventional technology]

Conventional liquid crystal video displays can be broadly classified into high-duty one-way type, two-terminal element panel type, and three-terminal element panel type. High-duty one-sided systems and similar systems include those using TN (Lysted Nematic) panels, those using 5TN (Super Lysted Nematic) panels, and those using SMC (Smectic C) panels. It is considered. Both attempts to increase the number of lines that can be driven by improving the steepness of the voltage-contrast curve of the panel. 2
As the terminal element panel, a panel using MIM elements,
There are devices in which a diode ring is formed using a diode characteristic element (amorphous diode or varistor).

As a 3-terminal element, amorphous TPT, polysilicon TFT1, and various other semiconductor materials are used.
It forms a T and has a liquid crystal panel. Panels using these two-terminal elements and three-terminal elements increase the number of lines that can be driven by controlling the input and output of signals to and from pixels by the element without relying on the steepness of the liquid crystal, and retaining the charge within the pixel. ing. The explanation of this case will focus on two-terminal element panels among the above-mentioned panels, especially MIM panels.

FIG. 4 is a plan view showing the arrangement of ffi poles of a conventional MIM panel. In this figure, the MIM element 41 is formed of tantalum-tantalum pentoxide-chromium, and the pixel f
This is an example in which f11442 is formed of ITO. The horizontal line 48 intersects each pixel connected to all the vertical lines 44.

Figure 5 below shows the electrode arrangement of a liquid crystal color display using a conventional MIM panel. Also in this example, the horizontal line 51 intersects each pixel 53 connected to all the vertical lines 52.

Figure 6 shows the horizontal line 51 and vertical line 5 shown in Figure 5.
20 is a diagram showing signals applied between 20 and Selection signal 6
1 and 62 are inverted every 1 field period 63.

The waveform applied to the liquid crystal within the pixel is as shown in 65.

[Problem that the invention seeks to solve]

However, with the above-mentioned technology, in panels with 400 or more horizontal lines, unless field memory (memory for video signals for -fields) is included in the circuit, images compatible with interlaced scanning cannot be obtained clearly. It was not possible to display the On the other hand, without having field memory 4
When a 7-inch channel with more than 0.00 horizontal lines was interlaced scanned at the television signal frequency, the signal of each pixel flickered and the image could not be seen clearly. This flickering becomes more visible the longer each pixel holds a signal.

In interlaced scanning, each pixel retains the signal for about 3
3m5 e c, the frequency is 15) 1z.

This is the frequency at which flickering is clearly visible to the human eye. Therefore, a conventional LCD video display has 20
The signals of the first field and the second field are superimposed on about 0 horizontal lines, and the writing frequency of each pixel is set to 30H.
Z and flickering are made invisible. 4 horizontal lines
In order to prevent flickering from appearing on more than 00 panels, the only way to prevent flickering from appearing is to provide field memory in the circuitry of conventional panels.

[Means for solving problems]

(i) The liquid crystal video display of the present invention is addressed by vertical lines and horizontal lines, where the vertical lines address pixels by odd-numbered horizontal lines and lines which address pixels by even-numbered horizontal lines. It is characterized by being drawn out in two parts.

(ii) An element is formed on one side of the substrate of the display.

(iii) The frequency of the signal that selects each pixel of the liquid crystal display described in item (i) is different between the first field and the second field, and one field of both fields has a frequency of the field scan frequency of the television. (30H2 in Japan) (hereinafter referred to as the equivalent field), and the other field is characterized by being an even multiple of the TV field scan frequency (hereinafter referred to as the even multiple field), and the pixel The polarity of the signal applied to the liquid crystal is inverted for each selection signal, and if one of the odd-numbered horizontal lines and the even-numbered horizontal lines of the liquid crystal display is an equal field, the other is always an even-multiplied field. It is characterized by being

(iv) The video signal (data signal) applied to the pixels of the same field period of the liquid crystal display arranged in items (i) and (i i) is a signal obtained by modulating the television signal into voltage amplitude or pulse width. and the video signal (data signal) applied to the pixels in the even field period.
is characterized by a constant voltage amplitude or pulse width that is independent of the television signal.

[Effect]

According to the above structure of the present invention, it is possible to drive a panel having 400 or more horizontal lines by interlaced scanning even though the circuit does not have a field memory. The flicker of
It can be made invisible. Therefore, it was possible to simplify the circuitry around the panel and form a panel with good resolution and contrast.

〔Example〕

FIG. 1 is a plan view showing the pixel arrangement of the present invention.
Pixels 17.18 connected to the vertical line 11 intersect with odd-numbered horizontal lines 13.15. Another vertical line 12
Pixels 19 and 20 connected to the even-numbered horizontal line 14
．． It intersects with 1B. As shown in this example, interlaced scanning is made possible without field memory by separating vertical lines that connect to pixels that intersect with odd-numbered horizontal lines and vertical lines that connect to pixels that intersect with even-numbered horizontal lines. I can do things.

FIG. 2 shows an example of a signal applied to each pixel of the present invention. In this example, the frequency at which the selection signals 24 and 25 appear in the even multiple field period 21 is set to twice the frequency of the equivalent field period 220. Curve 26.2 shows the voltage actually applied to the pixel liquid crystal.
It is 7. The selection signal for the equivalent field period changes in amplitude or pulse width depending on the gradation of the video signal. When the image is turned off, the selection signal becomes 28, and the voltage waveform applied to the liquid crystal becomes 27. On the other hand, the selection signal waveform in the even multiple field period 21 is always constant regardless of the video signal level.

FIG. 3 shows the effective value 32 of the on waveform and the effective value 3 of the off waveform of the image of the present invention with respect to the contrast curve 33 of the liquid crystal.
1 is shown. Compared to the difference between the effective value 34 of the high-duty ON waveform and the effective value 35 of the OFF waveform, the difference between the effective values of ON and OFF in the present invention is large, indicating that sufficient contrast can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to maintain good contrast at 40
This can be achieved with more panels than books. The above is MI
Although the explanation has been made using a panel using M elements, similar effects can be obtained with other active matrix panels (TPT etc.).

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the pixel arrangement of the present invention. FIG. 2 is a plan view showing the pixel arrangement of the present invention.
FIG. 3 is a diagram showing an example of a signal applied to each pixel of the present invention. FIG. 3 is a diagram showing the contrast curve of the liquid crystal, the effective value of the on waveform, and the effective value of the off waveform of the image of the present invention. FIG. 4 is a plan view showing the arrangement of electrodes of a conventional MIM panel. FIG. 5 is a diagram showing the electrode arrangement of a liquid crystal color display using a conventional MIM panel. ? FIG. J6 is a diagram showing signals applied between the horizontal line 51 and the vertical line 52 shown in FIG. 5. 64...Pulse width partial amount of selection signal Applicant Seiko Epson Co., Ltd. Representative Patent attorney Tsutomu Mogami and 1 other person Figure 3

Claims (1)

[Claims] 1) In a liquid crystal video display that is addressed by vertical lines and horizontal lines, the vertical lines address pixels by odd-numbered horizontal lines, and pixels by even-numbered horizontal lines. A liquid crystal video display characterized by being divided into lines and pulled out. 2) The liquid crystal video display according to claim 1, wherein an element is formed on one substrate of the liquid crystal display. 3) The frequency of the signal that selects each pixel of the liquid crystal display is different between the first field and the second field, and one of the two fields has a frequency equivalent to the field scan frequency of a TV (30Hz in Japan).
), and the other field (hereinafter referred to as the equivalent field) is characterized by an even multiple of the TV field scan frequency, and the polarity of the signal applied to the pixel liquid crystal is inverted for each selection signal. , and if one of the odd-numbered horizontal lines and the even-numbered horizontal lines of the liquid crystal display is an equal field, the other is necessarily an even-multiplied field. A liquid crystal video display as described in paragraph 1. 4) The video signal (data signal) applied to the pixels of the same field period of the liquid crystal display is a signal obtained by modulating the voltage amplitude or pulse width of the television signal, and is applied to the pixels of the even field period. 2. A liquid crystal video display according to claim 1, wherein the video signal (data signal) has a constant voltage amplitude or pulse width that is independent of the television signal.