JPS62236281A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To heighten the grade of display by shifting the center of image by about 1/2 picture element for each frame while scanning almost the whole of an effective display picture by each frame. CONSTITUTION:In each of the first and second scanning electrode groups, scan ning is made first by number one of the first scanning electrode 11 and number one of the second scanning electrode 12, then, by number two of the first scan ning electrode 11 and number two of the second scanning electrode 12 and so on. In the next frame, a switching means 61 outputs only scanning timing signals immediately, and outputs remaining scanning timing signals just before next clock. Thereby, a register 32b starts scanning 1 clock before a register 32a, and display position moves vertically by 1 scanning electrode pitch at each frame. As one picture element is constituted of two scanning lines and one signal electrode, an image moves vertically by amout 1/2 picture element. This means that display corresponding to twice the number of scanning lines is performed without increasing substantial number of scanning lines, and the exteme high-definition display is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION A) Industrial Application The present invention relates to a liquid crystal display device suitable for displaying television images.

(1) Conventional technology Television images have traditionally been displayed using a matrix display. For example, as shown in FIG. 8, a scanning circuit (3) is used for a liquid crystal display (1) having matrix electrodes. Connect the drive circuit (21) to the tuner (51)
The A/D converter (52) inputs the video signal from the computer into the register (22) as a predetermined digital amount, and these are driven synchronously to display the image. However, in many countries including Japan, television broadcasting uses interlaced scanning, and the positions of the scanning lines are different between even and odd fields. The position of the LCD will shift and a distorted image will be displayed.This is because liquid crystal displays cannot form very thin electrodes, cannot perform high time division driving, and the response characteristics of liquid crystals are inferior to CRTs. This is due to the fact that a large number of scanning lines cannot be taken. Therefore, Japanese Patent Application Laid-open No. 192477/1983 discloses that the even-numbered scanning electrodes and the odd-numbered scanning electrodes are alternately selected for each frame and the display position is shifted by one scanning line for each frame, similar to CRT display. has been done. However, this method is fine if the pixel density is high, such as a CRT, but it is particularly undesirable in cases where the total pixel density is less than 400 dots x 200 dots (200 scans) or less because the screen may appear to flicker or the roughness of the screen may become noticeable. do not have.

C) Problem 1 to be solved by the invention In view of the above points, the present invention solves the problem of image distortion even when displaying an interlaced scan display with a small number of scanning lines.
The present invention relates to a liquid crystal display device that can perform display without causing any unnaturalness or deterioration of display quality.

2) Means for solving the problem The present invention displays the riB elements in even frames and the pixels in odd frames so that they overlap and are shifted from the center. two sets per frame, scan the nth and n+1th scan electrodes together in one frame, and scan the nth and n-1th scan electrodes together in the next 71 norm, or A scan 1/i pole is used, and a different set of scans is scanned every frame using poles.

E) Effect: Since the image is moved up and down by approximately 1/2 pixel for each frame, no distortion occurs in the image, and since all pixels within the effective display surface are scanned in each frame, the display quality does not deteriorate.

〉 Embodiment Fig. 1 is a block diagram of a liquid crystal display device according to an embodiment of the present invention.
(10) is a simple matrix type liquid crystal display with scanning electrodes (
LL) < 11), , (12) (12)... and signal electrodes (13) (13)... ・Two scanning electrodes (11
) (12) and one signal TL pole (13) constitute one pixel.

So city scan tag (11) (11),,, (12)
(12)・、、Hasho 3I] 11 &A double + 1 (
2A+1), and the first scan electrodes (11) (11), = group and the second scan electrodes (12) ( 12) It is divided into groups.
(20> is the signal electrode (13) (1) of the liquid crystal display (10)
3)8. , a driver connected to
It outputs selection signals, non-selection signals, etc. (31) (31) are scan drivers connected to scan electrodes <11> (11), , (12) (12), . . . of the liquid crystal display (10) in groups, (32a) (32
b) is a register that provides a scanning signal to the scanning driver (31) (31j), and these registers constitute scanning means.

The registers (32a) and (32b) are real-in-parallel-out type shift registers that transfer data according to the clock (CL).
When the output of b) is H, the scan driver (31) (31) outputs the selection signal for scanning, and when the output is L, the scan driver (31) (
31) respectively output non-selection signals. The assembled driver (20) and scanning driver (31) <31) are supplied with bias voltages (for example, see Japanese Patent Laid-Open No. 60-2!2734) according to the respective signal levels from the bias circuit (40), Furthermore, the aforementioned selection signal and non-selection signal are formed based on the alternating current signal. (50) is a control circuit that receives a video signal (RF), establishes synchronization, and outputs an image signal <D), a frame signal, etc. (61) is a scanning timing signal (Sl) (
S2) is a switching means (frame start timing circuit) that outputs the register (32a) (32) of the scanning means.
b) is the scanning timing signal (S 1 ) (S 2
) as the data input of the shift register.

FIG. 2 is a timing chart of main parts of the liquid crystal display device of FIG. 1, and FIGS. 3(a) and 3(b) are schematic diagrams illustrating the display form. When the switching means (61) receives an odd frame signal from the control circuit (50), it outputs a scan timing signal (D) for one clock while the image signal (D) for vJl scan lines on the effective screen has been sent out. Sl) (S2) are output simultaneously. Therefore, the registers (32a) (32b) of the scanning means take in the scan timing signals (Sl) (S2) at the next clock (CL),
Since data is transferred by L), in each of the first and second scanning electrode groups, in order from the top of the figure, the first scanning electrode (11), the first scanning electrode (12),
Next, the second scanning electrode (11), the second scanning electrode (12), etc. are scanned, and in the next frame, that is, the switching means (61) is switched to the control circuit (50). When receiving an even frame signal from , the switching means (61) immediately outputs only the scanning timing signal (S2) and outputs the remaining scanning timing signal (Sl) immediately before the next clock. This register (32b)
starts scanning one clock ahead of the register (32a).

If we put these together, we get the table below, and if we display the same pattern, the display position will be one scan electrode pitch (i.e., the line width of the scan electrode + the electrode spacing) as shown in Figure 3 (a) and Figure 3 (b). ) will move up and down every frame. This is because one pixel is made up of two scanning lines and one signal electrode, so the image moves up and down by approximately 1/2 pixel, and the broadcast video uses interlaced scanning for each frame. Considering that image information is being sent, it is possible to reduce the number of scans by 1/A for the liquid crystal display (10) without actually increasing the number of scans.
If the duty ratio is not changed in the case of duty ratio, display equivalent to twice the number of scanning lines is performed, and the display quality is extremely high.

FIG. 4 in the margin below is a block diagram of a liquid crystal display device according to another embodiment of the present invention, in which parts common to FIG. 1 are given the same numbers. In this figure, (14) is also a simple matrix type liquid crystal display, but as shown in Figure 5, scanning electrodes (16) (16
), , (17) (17), , are provided in the second calendar.

First scan electrode (16) (16”) in each layer
The number of second scanning electrodes (17) (17) is the same as the number of scanning lines in each group (i.e., the number of second scanning electrodes (17) (17),
16) (1G), , (17) The total number of (17), , is twice the number of scanning lines A), and each scanning electrode has two electrodes from other groups, except for those located at the ends. It is provided overlapping the scanning electrode. (33a) and (33b) are registers that provide scanning signals to the scanning drivers (31) and (31);
Cascaded. Therefore, the switching means that switches the output of the scanning means so that the center of the pixel moves for each frame leads the final bit output of the register (33a) to the register (33b), but there is no clock play between frames. When it is scanned continuously, only the connection line is used, but in reality, the scanning is paused for the processing time of the vertical retrace line, so data for the corresponding period of time must be transferred emptyly, so there is no delay during that time. register (62) is also included in the switching means.In the configuration where the
scanned by the scanning electrodes (16) (16), .
Even frames are the second scanning electrode (17) (17) 0
1. Scanned by As a result, as shown in Figure 6, the display in odd-numbered frames (the lit part is indicated by the diagonal line in the upper left) and the display in even-numbered frames (the lit part is indicated by the shaded area in the upper right) are approximately 1/2 pixel. The second scanning voltage m(17)(
Since the electrodes 17), .

Although the embodiments described above have been exclusively taken as examples of black and white display, the present invention can also be applied to color display. FIG. 7 takes a case based on the embodiment shown in FIG. 1 as an example, and displays only the pixel R1.
A pixel is not considered as an element for each color, but a pixel is defined as a pixel in which all three colors, RGB, are arranged in a triangular shape. The pixels surrounded by solid lines in the 7th ward (1g>(1g),...

indicates l''11 pixels in an odd frame, and pixels (19), (19), surrounded by broken lines indicate "1 pixel" in an even frame. The set of scanning staggered electrodes is the same as in the case of FIG. 1, and the poles of 1 thickness are not rod-shaped but ζ-shaped.

g) Effects of the invention As described above, substantially the entire effective display screen is covered with each screen.
Since the center of the image is shifted by approximately 1/2 pixel for each frame 11 during scanning, there is no image distortion, and the display quality is improved because it looks as if there are twice the number of scanning lines.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a liquid crystal display device according to an embodiment of the present invention.
Figure 2 is the main part timing chart, Figure 3 (a) (
b) is a schematic diagram of the display, FIG. 4 is a block diagram of a liquid crystal display device according to another embodiment of the present invention, FIG. 51 is a cross-sectional view of the liquid crystal display used in the example of FIG. Schematic diagram of the display of the figure,
FIG. 7 is a schematic diagram of a display for use in color display according to the present invention, and FIG. 8 is a block diagram of a conventional liquid crystal display device. (10)(14)...Liquid crystal display, (11)(11),
,,(12)(12)...(16)(16),,,
(17) (17) -0, ... scanning electrode, (13) (1
3)...°° signal electrode, <20)゛-゛driver, (31) (31>...scan dry, <, C32a) (32b) <33a> (33b
) = Register, (40) Bias circuit, (50
)...control circuit, (61)...switching means, (62)
・・・Shijita for delay.

Claims (1)

[Scope of Claims] 1) A matrix-type liquid crystal display having a scanning electrode group and a signal electrode group, in which a pixel is formed by the intersection of both electrode groups, and a driver connected to the signal electrode group of the liquid crystal display. and a scanning means for sequentially applying a scanning voltage to the scanning electrode group, and a switching means for switching the output of the scanning means so that the center of the pixel moves within a range smaller than the size of one pixel for each frame. LCD display device. 2) The number of the scanning electrode groups is more than twice the number of scanning lines, and the switching means scans both the n-th and n+1-th scanning electrodes in one frame, and scans the n-th and n-1th scanning electrodes in the next frame. 2. The liquid crystal display device according to claim 1, wherein the scanning electrodes are switched to scan together. 3) The scanning electrode group includes a first scanning electrode group and a second scanning electrode group having mutually overlapping parts, and the switching means switches between the first scanning electrode group and the second scanning electrode group every frame. A liquid crystal display device according to claim 1, characterized in that: 4) The first and second scanning electrode groups are provided in separate layers, and each scanning electrode overlaps with the other two scanning electrodes, as claimed in claim 3. The liquid crystal display device described.