JPH01280787A - Liquid crystal display body - Google Patents

Abstract

PURPOSE:To form a liquid crystal display body which does not produce any after image by tentatively displaying the 2nd picture whose bright-dark relation by dots is inverted against the 1st picture which displays the same video or character for more than fixed time. CONSTITUTION:After the 1st picture which displays characters 2 fixed in the same state for more than fixed time of, for example, characters shown as figure KATAKANA (square form of Japanese syllabary) written in black color on white ground 1 is displayed, the 2nd picture which displays the characters 4 shown as figure KATAKANA (square form of Japanese syllabary) written in white color on black ground 2 so that the bright-dark relation can be inverted from that of the 1st picture is tentatively displayed. At the time of the inverted display, the dots constituting the characters 2 and ground 1 in the 1st picture respectively display white and black in the 2nd picture. Therefore, even when 'E X SON' 5 is displayed in the 3rd picture thereafter, the after image of the characters 2 shown as figure KANAKANA (square form of Japanese syllabary) is not produced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to dot matrix liquid crystal display devices that display static images, text information, etc. that are fixed for a certain period of time, such as displays on televisions, personal computers, word processors, etc. Regarding display body.

[Prior art 1] Due to the increase in display capacity, recent dot matrix liquid crystal displays have come to be used in place of conventional CRTs (cathode ray display tubes) in displays such as televisions, personal computers, and word processors. Ta.

For example, when used as a television, images that remain the same for a certain period of time may be displayed, such as still images from a video deck or video disc, or functions such as time, channel, and volume. Furthermore, on the displays of personal computers, word processors, and the like, characters and graphics may be displayed in a fixed manner for a certain period of time or longer.

[Problem to be Solved by the Invention 1] However, in the above-mentioned prior art, when the screen is switched from the display content that has been fixed for a certain period of time to another display content, the previous content remains as it is for a while. It is said that it can be seen.
There is a problem in that a so-called afterimage phenomenon occurs.

For example, as shown in Figure 2 (a), "Se x Koe x Son"
After displaying the character 2 for a while, the display content is changed to rEXsONJ 5 as shown in Fig. 2(b).
The words ``Koe x Son'' appear for a while as a faint afterimage 6. At this time, an afterimage occurs even if the characters are black on a white background 1 as shown in FIG. 2, or white characters on a black background (not shown). Furthermore, even if the background, characters, etc. are colored, or even if the background, characters, etc. have intermediate brightness, the same afterimage will still occur.

SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and its purpose is to provide a liquid crystal display that does not cause afterimages.

[Means for Solving the Problems 1] The liquid crystal display of the present invention is a liquid crystal display of a driver 1 to a matrix that displays a first screen that displays images or characters that are fixed in the same state for a certain period of time. It is characterized in that a second screen whose brightness relationship in dot units is opposite to that of the first screen is temporarily not displayed.

[Example] Examples will be described below using figures.

Example-1 As shown in Fig. 1(a), "SE×KOE×
character 2 that remains in the same state for a certain period of time
After projecting the first screen displaying , as shown in Figure 1(b), a white "Section" is placed on the black background 3 so that the brightness relationship is opposite to that of the first screen in (a). A second screen that displays the characters 4 "×Koe×Son" is temporarily displayed. At this time,(
The dots that were displayed black to make up character 2 in (a) are now displayed white in (b), and the dots that were displayed white to make up background 1 in (a) are now shown in (b). ) displays black.

After this, rEXs as shown in FIG. 1(c).

Even if it is displayed as Nl2, [Character 2 of [Se x Koe X Son J]
No afterimage occurs.

At this time, the time to maintain (one) second screen is (a
) depends on how long the first screen lasts, but it is said that the length may be approximately one tenth of the first screen.

Possible causes of the afterimage phenomenon include the accumulation of electric charges on the alignment surface of the liquid crystal display, or the weak force for rearranging the liquid crystal molecules after the display signal is removed. The second screen appears to be in a state where the surface charge generated in (a) is removed or the rearrangement of liquid crystal molecules is promoted.

Example 2 The second example is a case of colored display. This embodiment will also be explained using FIG. On the first screen in Figure 1(a),
Assume that the background l is red and the character 2 is green. At this time (
As the second screen in b), if the background 3 is cyan (blue-green), which is the complementary color of red, and the character 4 is displayed as -1 in magenta (red-purple), which is the complementary color of green, then the afterimage will still appear in (C). does not occur.

The reason why the second screen displays the complementary color of the first screen will be explained. In the optical full-color dot matrix liquid crystal display, each dot is colored red, green, or blue, and the liquid crystal portion of each dot is used as a light shutter to represent the color.

For example, to represent red as in the background l in Figure 1(a), the green dots and blue dots are darkened, and the red dots are brightened.Then, in (b), the light-dark relationship for each dot is shown. (
Since we will do the opposite of a), we will darken the red dots and brighten the green and blue dots.

The displayed color then becomes cyan, which is an additive mixture of green and blue (i.e., the complementary color of red).

Since the afterimage phenomenon occurs on a dot basis, if the second screen is made to have the opposite brightness relationship on a dot basis from the first screen, it will be possible to create a liquid crystal display without afterimages even when displaying colors. is obtained.

Example 3 The third example is a case where the background, characters, etc. have intermediate brightness. This will also be explained using FIG. Pure white is white 10
0%, and pure black is defined as 0% white, then suppose that the background l of the first screen in FIG. 1(a) is 80% white, and the character 2 is 15% white. At this time, in the second screen of Figure 1(b), if the background 3 is set to 20% white and the text 4 is set to 85% white, so that the brightness relationship in dot units is reversed, (C) Sometimes no afterimage occurs.

Also, even if the background or text is colored with medium brightness,
The second point should be set so that the brightness relationship is reversed for each dot.
The effects of the present invention can be obtained by displaying the screen.

The liquid crystal display of the present invention is effective whether it is a black and white display or a color display, and is effective regardless of the display mode such as Twisted Nemagic, Super Rice 1 to Nemagic, or Guest Host. Both simple and active matrices are effective in history.

[Effect of the Invention 1] As explained above, according to the present invention, the second screen, in which the brightness relationship in dot units is opposite to the first screen that displays the same image or characters for a certain period of time, is used. By temporarily displaying images, the charge on the alignment surface is removed or the rearrangement of liquid crystal molecules is promoted, so that a liquid crystal display without afterimages can be obtained.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(c) are plan views of the screen of a liquid crystal display according to the present invention, and FIGS. 2(a) and 2(b) are plan views of a conventional liquid crystal display. ]...Background of the first screen 2...Character 3 of the first screen...Background 4 of the second screen...Character 5 of the second screen...Other characters 6...・Applicant for afterimage and above Seiko Epson Co., Ltd. Agent Patent attorney Mogami Pffi (-, F 1 person)
Kube・l・゛・−

Claims (1)

[Claims] In a dot matrix liquid crystal display that displays a first screen that displays images or characters that are fixed in the same state for a certain period of time, a second screen whose brightness relationship in dot units is opposite to that of the first screen. A liquid crystal display that temporarily displays images.