JPH0497320A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To display an image of high quality which has no linear display defect by providing a light shield film at the breadthwise center part of a wide scanning electrode corresponding to the border part between two display areas. CONSTITUTION:A signal electrode 5 is divided into two at its lengthwise intermediate part to divide a display area into two areas and a scanning electrode corresponding to the border part between the two of four areas between scanning electrodes is formed as a wide electrode 40 which is almost twice as wide as other scanning electrodes. Further, the light shield film 10 which is nearly as wide as respective scanning electrode intervals is provided at the breadthwise center part of the wide scanning electrode 4a. Then the light shield film 10 restricts the size of picture elements displayed at the confrontation parts between the wide scanning electrode 4a and end parts of signal electrodes 5 in the respective display areas. Therefore, although the display area is divided into the two areas and two-divisional driving is performed, the picture elements displayed at the border part between the display areas never becomes large even if there is an error in the positioning accuracy of a couple of substrates. Consequently, the image of high quality which has no linear display defect can be displayed.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a liquid crystal display element.

[Conventional technology]

Some liquid crystal display elements for displaying television images, etc., have scanning electrodes formed on one of a pair of substrates facing each other with a liquid crystal layer in between, and signal electrodes orthogonal to the scanning electrodes formed on the other substrate. .

In order to increase the resolution of this liquid crystal display element, it is desirable to increase the number of display pixels by increasing the number of scanning electrodes, but the driving duty to obtain sufficient contrast is approximately 1/200 to 1/400. is the limit, so the number of scanning electrodes is limited to about 200 to 400.

For this reason, conventionally, the display area of the liquid crystal display element is divided into two areas by dividing the signal electrode into two at the middle part in the length direction, and one half of the display image is displayed in one area, and the other half is displayed in the other area. It is considered that the display can be performed in the other area, and in this way, the liquid crystal display element can be used in half of the total number of scanning electrodes.
Since the display can be driven with a drive duty of , even if there is a limit to the drive duty, the resolution can be increased by doubling the number of scanning electrodes.

6 and 7 show conventionally known liquid crystal display elements of this type, with FIG. 6 being a sectional view of the liquid crystal display element, and FIG. 7 being a diagram of its electrode pattern. In addition,
In FIG. 7, the scanning electrodes and the substrate on which the scanning electrodes are formed are shown by broken lines, and the signal electrodes and the substrate on which the signal electrodes are formed are shown by solid lines.

6 and 7, reference numerals 1 and 2 in the figures are a pair of transparent substrates made of glass or the like that are polymerized and bonded via a frame-shaped sealing material 3, and a nematic liquid crystal is placed between the side substrates 1. LC is included.

A large number of striped transparent signal electrodes 4 are formed parallel to each other on the surface of one substrate 1 facing the liquid crystal layer, and striped transparent signal electrodes 4 perpendicular to the signal electrodes 4 are formed on the surface of the other substrate 2 facing the liquid crystal layer. A large number of transparent scanning electrodes 5 are formed in parallel to each other, and the cross-opposing portions of each signal electrode 4 and each scanning electrode 5 serve as pixel display portions. moreover,
On the electrode formation surface of the side substrate 1゜2, alignment films 6,
7 is formed, and the molecules of the nematic liquid crystal LC sealed between the side substrates 1 and 2 are arranged in a twisted manner between the side substrates 1 and 2. Moreover, 8.9 is a pair of polarizing plates respectively arranged on the outer surface side of the side substrate 1.2. Note that liquid crystal display elements that display television images and the like are generally of a normally black display type in which light is transmitted through the liquid crystal layer by applying an on electric field, and light is blocked by applying an off electric field to the liquid crystal layer.

And, in this liquid crystal display element, each signal type! By dividing 5 into two at the midpoint in the length direction, the display area is divided into two areas A, , A2. Furthermore, the scanning electrode 4a corresponding to the boundary between these two display areas A, A2 has a width approximately twice that of the other scanning electrodes 4 (the total width of the width of the two scanning electrodes 4 and the interval between them). ), and the wide scanning electrode 4a at this boundary faces the end of each signal electrode 4 in one area A and the end of each signal electrode 4 in the other area A2. It is considered to be a common electrode.

This liquid crystal display element is driven for display by two-division drive in which scanning electrodes 4 are sequentially selected for each display area A, A2, and an image data signal is applied to signal electrodes 5 in synchronization with this. One half of the image is displayed in one display area A, and the other half is displayed in the other display area A2. Note that the scanning electrodes 4.4a first select the wide scanning electrodes 4a at the boundaries of each display area A, A2, and then select the wide scanning electrodes 4a at the boundaries of each display area A2.
,.

The scanning electrodes 4 of A2 are selected sequentially from the boundary side, or in the reverse selection order.

[Problem to be solved by the invention]

However, in the above conventional liquid crystal display element, if there is an error in the alignment accuracy of the pair of substrates 1 and 2, one of the pixels displayed at the boundary between the display areas A, A2, The problem was that the pixels were displayed large.

That is, FIGS. 8 and 9 respectively show each display area AH in the conventional liquid crystal display element.

It shows the pixel display state near the boundary of A2, and if there is no error in the alignment accuracy of the pair of substrates 1.2, the end of the signal electrode 5 of each display area A+, A2 and the wide scanning electrode 4a. Since the facing area of each display area A is almost equal, each display area A
, , A2's boundary side display pixels D (pixels indicated by hatching in the figure) are displayed in approximately the same size as shown in FIG.

However, when assembling a liquid crystal display element, a pair of substrates 1.
2 is adhered with a positional deviation error in the length direction of the signal electrode 5, the signal electrode 5 of one display area A1 or A2 is shifted away from the wide scanning electrode 4a and the end of the signal electrode 5 is The area facing the wide scanning electrode 4a becomes smaller, and the signal electrode 5 of the other display area A2 or A1 shifts toward the wide scanning electrode 4a, and the area facing the end of the signal electrode 5 and the wide scanning electrode 4a becomes larger. Therefore, in this case, as shown in FIG. 9, one of the display pixels on the boundary side of each display area A1 and A2 (A+ in the figure)
The pixel size on the side is small, and the pixel size on the other display area (A2 in the figure) is large.

In this way, when the pixels in any one of the display areas on the boundary side of each display area A, A2 are displayed in a large size, the pixels displayed in a large size become conspicuous. As a result, a linear display defect occurs at the center of the display image (at the boundary between the display areas A, , A) due to the large pixel row.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to divide the display area into two areas and drive the display area in two, but it is possible to divide the display area into two areas and drive the display area in half. A liquid crystal display element that can display high-quality images without linear display defects, which prevents the pixels displayed at the boundaries of the display area from becoming larger even if there is an error in alignment accuracy. Our goal is to provide the following.

[Means to solve the problem]

The liquid crystal display element of the present invention divides the signal electrode into two at the middle part in the length direction to divide the display area into two areas,
Among the scanning electrodes, the scanning electrode corresponding to the boundary between the two regions is made into a wide electrode that is approximately twice as wide as the other scanning electrodes, and at the center in the width direction of this wide scanning electrode, there is a gap between each scanning electrode. The invention is characterized in that a light-shielding film is provided with a width that is approximately equal to the distance between the two.

[Effect]

That is, in the present invention, by providing a light-shielding film at the center in the width direction of the wide scanning electrode corresponding to the boundary between two display areas, the connection between the wide scanning electrode and the end of the signal electrode of each display area is prevented. The size of the pixel displayed on the opposing part is regulated by the light-shielding film, and as mentioned above, the width of the wide scanning electrode is approximately twice that of the other scanning electrodes, and the width of the wide scanning electrode is approximately twice that of the other scanning electrodes. If the width of the light-shielding film provided at the center in the width direction is made almost equal to the spacing between each scanning electrode, misalignment errors between the pair of substrates will cause the end of the signal electrode in one of the display areas to overlap the wide scanning electrode. Even if the opposing area becomes larger, the pixels displayed in this portion will have approximately the same size as the pixels displayed in the opposing portions of the other scanning electrodes and signal electrodes.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 is a sectional view of a liquid crystal display element, FIG. 2 is an electrode pattern thereof, and FIG. 3 is an enlarged sectional view of a wide scanning electrode. In addition, in FIGS. 1 to 3, the same reference numerals are given to the parts having the same structure as those of the conventional liquid crystal display element shown in FIGS. 6 and 7, and the explanation thereof will be omitted.

This embodiment consists of a pair of substrates 1 facing each other with a liquid crystal layer in between.
, 2, in which a large number of scanning electrodes 4 are formed on one substrate 1 and a large number of signal electrodes 5 orthogonal to the scanning electrodes 4 are formed on the other substrate 2. is divided into two at the middle part in the length direction to divide the display area into two areas A, A2, and scan electrodes corresponding to the boundaries of two display areas A + and A2 of the scan electrodes 4. 4a is a wide electrode having a width approximately twice that of the other scanning electrodes 4 (the total width of the width of two scanning electrodes 4 and the interval between them), and a central part of the wide scanning electrode 4a in the width direction is formed. , a light shielding film 10 having a width approximately equal to the spacing between each scanning electrode 4 is provided. Note that the light shielding film 1
0 is a metal film such as chromium, and this light shielding film 10 is formed in a stripe shape over the wide scanning electrode 4a over the length of the opposing portion of the signal electrode 5.

This liquid crystal display element is of a normally black display type, in which light is transmitted by applying an on-field to the liquid crystal layer, and light is blocked by applying an off-field to the liquid crystal layer, as shown in Figures 6 and 7. Similar to the conventional liquid crystal display element, the display is driven by two-division driving in which the scanning electrodes 4 are sequentially selected for each display area A, .

In the liquid crystal display element of this embodiment, wide scanning electrodes 4 corresponding to the boundaries between the two display areas A, .
Since the light-shielding film 10 is provided at the center in the width direction of a, the size of the pixel displayed at the opposing portion of the wide scanning electrode 4a and the end of the signal electrode 5 of each display area A + , A 2 is It can be controlled by the light shielding film 10. Further, in this liquid crystal display element, the width of the wide scanning electrode 4a is approximately twice that of the other scanning electrodes 4, and the width of the light shielding film 10 provided at the center of the wide scanning electrode 4a in the width direction is set between each scanning electrode 4. Since the distance between the substrates 1 and 2 is approximately equal to that of the display area A, a positional deviation error between the pair of substrates 1 and 2 may cause the display area (A.

Alternatively, even if the opposing area between the end of the signal electrode 5 and the wide scanning electrode 4a in A2) becomes large, the pixels displayed in this area will not be displayed in the opposing area between the other scanning electrode 4 and the signal electrode 5. The size of the pixel is approximately the same as that of the pixel.

That is, FIG. 4 and FIG. 5 respectively show the pixel display state near the boundary of each display area A, A2 in the liquid crystal display element, and there is no error in the alignment accuracy of the pair of substrates 1.2. In this case, display pixels on the boundary side of each display area A, A2 (pixels indicated by hatching in the figure) D
are displayed in approximately the same size as shown in FIG.

On the other hand, when assembling a liquid crystal display element, a pair of substrates 1.2
If the signal electrode 5 is adhered with a positional deviation error in the length direction, the signal electrode 5 in one display area A or A2 will shift away from the wide scanning electrode 4a, and this signal electrode 5 will shift away from the wide scanning electrode 4a.
The opposing area between the end of the wide scanning electrode 4a and the wide scanning electrode 4a becomes smaller,
The signal electrode 5 in the other display area A2 or A1 is shifted toward the wide scanning electrode 4a, and the opposing area between the end of the signal electrode 5 and the wide scanning electrode 4a becomes large. The signal electrode 5 has a larger opposing area.
Since the size of the pixel displayed in the area facing the wide scanning electrode 4a is regulated by the light shielding film 10, this pixel is separated from other scanning electrodes 4 and signals as shown in FIG. It is displayed in approximately the same size as the pixel displayed on the portion facing the electrode 5.

As described above, although this liquid crystal display element divides the display area into two areas A and A2 and drives them in two, there is an error in the alignment accuracy of the pair of substrates 1.2. Also, the pixels displayed at the boundary between the display areas A1 and A2 do not become large, and therefore a high-quality image without linear display defects can be displayed.

However, also in this liquid crystal display element, the pair of substrates 1.
If there is a positional shift error in 2, one of the display pixels on the boundary side of each display area A, A2 (
As the pixel difference of A+ or A2) becomes smaller as shown in Figure 5, and the pixel difference of one display area becomes smaller, the distance between this pixel and the pixel of the other display area (one side becomes smaller). The distance between the pixel of the display area and the light shielding film 10,
(total width with the width of the light-shielding film lO) becomes larger, but since this interval is a part through which no light passes, this interval is not noticeable, and the reduction in pixel density has almost no effect on display quality. .

Note that in the above embodiment, the light shielding film 10 provided at the widthwise central portion of the wide scanning electrode 4a is formed on the wide scanning electrode 4a; however, this light shielding film 10 is formed below the wide scanning electrode 4a. You may.

〔Effect of the invention〕

According to the liquid crystal display element of the present invention, a light-shielding film is provided at the center in the width direction of the wide scanning electrode corresponding to the boundary between two display areas, and the wide scanning electrode and the end of the signal electrode of each display area are connected to each other. Since the size of the pixels displayed on the opposing parts of the substrate is regulated by the light shielding film, the display area is divided into two areas and driven in two, but the position of the pair of substrates is Even if there is an error in alignment accuracy, the pixels displayed at the border of the display area will not become larger, and therefore a high-quality image without linear display defects can be displayed.

[Brief explanation of the drawing]

Figure 1~? Figure 6 shows an embodiment of the present invention, Figures 1 and 2 are a cross-sectional view of a liquid crystal display element and its electrode pattern, Figure 3 is an enlarged cross-sectional view of a wide scanning electrode, and Figure 4 is a cross-sectional view of a wide scanning electrode. and FIG. 5 are diagrams each showing the pixel display state near the boundary of the display area. Figures 6 to 9 show conventional liquid crystal display elements, Figures 6 and 7 are cross-sectional views of the liquid crystal display element and its electrode patterns, and Figures 8 and 9 are respectively display areas. FIG. 3 is a diagram showing a pixel display state near the boundary of FIG. 1.2... Substrate, 4... Scanning electrode, 4a... Wide scanning electrode, 5... Signal electrode, 6, 7... Alignment film, L
C...Liquid crystal, 8,9...Polarizing plate, A r, A
2...Display area, D...Display pixel. Applicant's Representative Patent Attorney Takehiko Suzue Figure 2 Figure 6 Figure 7 Figure a Figure 3 Figure 4 Figure 5 Figure 8 Figure 9

Claims (1)

[Claims] In a liquid crystal display element in which a large number of scanning electrodes are formed on one of a pair of substrates facing each other with a liquid crystal layer in between, and a large number of signal electrodes orthogonal to the scanning electrodes are formed on the other substrate,
The display area is divided into two areas by dividing the signal electrode into two at the middle part in the length direction, and the scanning electrode corresponding to the boundary between the two areas among the scanning electrodes is placed almost between the other scanning electrodes. 1. A liquid crystal display element comprising a wide electrode having a width twice as wide as that of the wide scanning electrode, and a light-shielding film having a width approximately equal to the spacing between each scanning electrode at the center of the wide scanning electrode in the width direction.