JPH0125070B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a liquid crystal display device.

BACKGROUND ART Recently, two-layer type liquid crystal display devices have been commercialized, which include two upper and lower liquid crystal display layers and which display two types of display by switching between the two display layers.

However, this two-layer liquid crystal display device has only one
Although one display device can display the same amount of information as two display devices, it has the disadvantage that it is quite thick because its structure is essentially a stack of two liquid crystal display cells. .

In order to solve these drawbacks, the
A liquid crystal display device using a two-layer electrode substrate as disclosed in No. 108418 has been proposed. In this liquid crystal display device, two layers of electrodes are provided on each of the inner surfaces of a pair of opposing substrates with an insulating layer interposed therebetween, and the upper layer electrode is formed with a window corresponding to the display pattern formed by the lower layer electrode. A segment signal is supplied to the lower layer electrode of the substrate, the upper layer and lower layer electrode of the other substrate and the upper layer electrode of one substrate are set at the same potential, and a voltage higher than the threshold voltage with respect to the potential of the segment electrode is applied to the liquid crystal. A signal having a potential such as that applied to the display is supplied, and thereby a plurality of patterns can be displayed.

However, the above-mentioned liquid crystal display device has a large number of terminals and is difficult to display a complex pattern with a large number of segment electrodes because one terminal is connected to one segment electrode and the device is statically driven. At the same time, a high voltage equal to the driving voltage of the liquid crystal is applied between the lower layer electrode and the upper layer electrode of one substrate, and the lower layer electrode and the upper layer electrode mentioned above are overlapped with each other via an insulating film, so during this time Since this is equivalent to connecting a capacitor with a large capacity to the capacitor, current flows through the capacitor between the upper and lower electrodes, resulting in a large power loss.

This invention has been made in view of the above-mentioned circumstances, and its object is to provide two kinds of It is an object of the present invention to provide a liquid crystal display device which can reduce the number of terminals by arranging electrodes for dynamic driving in two layers, can display a large number of patterns with a large number of segment electrodes, and has low power consumption.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 and 2 are a pair of upper and lower transparent substrates (for example, glass plates);
The substrates 2 are adhesively polymerized via a frame-shaped sealing material 3, and the gap between the two substrates 1 and 2 is filled with liquid crystal (not shown). 4, 4 are both the substrates 1,
2, for example, the inner surface (lower surface) of the upper substrate 1
A plurality of groups of segment electrodes for dynamic driving (hereinafter referred to as first segment electrodes) are formed in a plurality of groups, and the segment electrodes 4, 4 have a pattern as shown in FIG. 2, for example. 5,
5 is the inner surface (top surface) of the other substrate, that is, the lower substrate 2
A plurality of groups of segment electrodes for dynamic driving (hereinafter referred to as second segment electrodes) are formed in a plurality of groups, and the segment electrodes 5, 5 have a pattern as shown in FIG. 3, for example. In addition, in this embodiment, each of the segment electrodes 4, 4
and 5, 5 are formed directly on the substrates 1, 2, but these segment electrodes 4, 4 and 5, 5 may be formed on transparent insulating layers formed on the substrates 1, 2. . 6 is a transparent insulating layer covering all the first segment electrodes 4, 4 formed on the inner surface of the upper substrate 1 and their leads 4a, 4a; 7 is a transparent insulating layer covering all the second segment electrodes 4, 4 formed on the inner surface of the lower substrate 2; This is a transparent insulating layer that covers the segment electrodes 5, 5 and their leads 5a, 5a, and these insulating layers 6, 7 are formed on substantially the entire surface of the substrates 1, 2. On the other hand, 8,
9 are two dynamic drive common electrodes formed on the insulating layer 6 of the upper substrate 1; 10;
Reference numeral 11 denotes two dynamic drive common electrodes formed on the insulating layer 7 of the lower substrate 2, and common electrodes 8, 11 formed on the upper electrode substrate 1.
Reference numeral 9 serves as a common electrode for the second segment electrodes 5, 5 on the lower substrate 2 side, and common electrodes 10, 11 formed on the lower substrate 2 serve as common electrodes for the first segment electrodes 4, 4 on the upper substrate 1 side. The pattern is as shown in FIGS. 2 and 3. Further, the common electrodes 8 and 9 formed on the upper substrate 1 are formed except for the portions that overlap with the effective areas of the respective first segment electrodes 4 and 4 on the own substrate (upper substrate 1) side, In this embodiment, each of the first segment electrodes 4, 4 is formed to be slightly larger than the actual display pattern, and the common electrodes 8, 9 have portions overlapping with each of the first segment electrodes 4, 4 that are larger than the actual display pattern. It has a shape in which missing portions 8a and 9a are formed to match the contour. This also applies to the common electrodes 10 and 11 formed on the lower substrate 2, and the common electrodes 10 and 11 are connected to the respective second segment electrodes 5 and 5 (actual display pattern) on the own substrate (lower substrate 2) side. The cutout portions 10a and 11a, which are shaped to match the outline of the actual display pattern, are formed in the portions that overlap with the contours of the actual display pattern. That is, each of the common electrodes 8, 9 and 10, 11 also serves as a shielding electrode that defines the effective area of the segment electrodes 4, 4 and 5, 5 on the own substrate side, and the first segment electrode 4,
4, the common signal is applied to the common electrodes 8 and 9 on the upper substrate 1 side where the first segment electrodes 4 and 4 are formed (the common signal is applied to the common electrodes 10 and 11 on the lower substrate 2 side). A shielding signal having a potential difference lower than the threshold voltage of the liquid crystal is applied to the potential of the common signal), and when the segment signal is applied to the second segment electrodes 5, 5, the second segment electrodes 5, 5 are formed. If a shielding signal having a potential difference lower than the potential of the common signal (the common signal applied to the common electrodes 8 and 9 on the upper substrate 1 side) is applied to the common electrodes 10 and 11 on the lower substrate 2 side, each of the above-mentioned segment electrode 4,
Even if 4, 5, and 5 are larger than the actual display pattern, common electrodes 8, 9, and 10,
A voltage higher than the threshold voltage acts only on the portions corresponding to the missing portions 8a, 9a and 10a, 11a of 11. That is, the effective areas of each of the segment electrodes 4, 4 and 5, 5 include portions (missing portions 8a, 9a and 10a,
11a), and its shape corresponds to the actual display pattern. In this embodiment, the reason why the segment electrodes 4, 4 and 5, 5 are made larger than the actual display pattern is because the common electrodes 8, 9 and 1 are made larger than the actual display pattern.
This is to easily align the missing portions 8a, 9a and 10a, 11a formed at the segment electrodes 4, 4 and 5, 5 with respect to the segment electrodes 4, 4 and 5, 5.

Moreover, each of the segment electrodes 4, 4 and 5, 5
As shown in FIGS. 2 and 3, the two electrodes 4, 4 and 5, 5 are made into one group and are commonly connected for each group, and the common electrode 8 formed on the upper substrate 1 , 9, one common electrode 8 faces one second segment electrode 5, 5 of each group formed on the lower substrate 2, and the other common electrode 9 faces the other second segment electrode 5, 5 of each group formed on the lower substrate 2. 5, 5 are formed to face each other. In addition, the common electrode 1 formed on the lower substrate 2
0 and 11, one of the common electrodes 10 faces one of the first segment electrodes 4 and 4 of each group formed on the upper substrate 1, and the other common electrode 11
are formed to face the other first segment electrodes 4, 4 of each group. Further, among the segment electrodes 4, 4 and 5, 5, those located at positions facing the segment electrodes 5, 5 and 4, 4 formed on the other substrate 2, 1,
It also serves as a part of the common electrode for the segment electrodes 5, 5 and 4, 4 formed on the other substrate 2, 1, thereby preventing the omission of each of the common electrodes 8, 9 and 10, 11. Parts 8a, 9a
and 10a, 11a are supplemented. For this purpose, each of the segment electrodes 4, 4 and 5, 5 is located within the area of one common electrode 8, 10 on the side of its own substrate, and within the area of the other common electrode 9, 11. It is said to be a group structure in which things are commonly connected. Note that each of the electrodes 4, 5, 8, 9, 10, and 11 is made of a transparent electrode material such as indium oxide. Further, alignment films for aligning liquid crystal are formed on the electrode-forming surfaces of the substrates 1 and 2, if necessary. Further, in FIGS. 1 and 2, reference numerals 1a and 1a are terminal array portions formed on both sides of the upper substrate 1, and each group formed on the upper substrate 1 is provided in the terminal array portions 1a and 1a. Terminals 4b, 4b of the first segment electrodes 4, 4 and terminals 8b, 9 of each common electrode 8, 9
b is drawn out and formed, and these terminals 4b, 8
Second segment electrodes 5, 5 of each group on the lower substrate 2 side in line with b, 9b and each common electrode 10,
Terminals 5b, 5b and 10b, 11 corresponding to 11
b is formed. Also, in Figure 3, 5c,
5c are terminals of the second segment electrodes 5, 5 of each group formed on the lower substrate 2; 10c, 11;
c is a terminal of each common electrode 10, 11, and each of these terminals 5c, 5c and 10c, 11c is connected to each of the terminals 5b, 5b, 10b, 11b on the upper substrate 1 side via a transfer member (not shown). ing.

Next, the display operation of the liquid crystal display device of this example will be explained.

This liquid crystal display device has a display according to the shape of the effective area of the first segment electrodes 4, 4 formed on the upper substrate 1, and a shape of the effective area of the second segment electrodes 5, 5 formed on the lower substrate 2. In this embodiment, both of the above-mentioned two types of display are displayed by dynamic driving at 1/2 duty.

First, a case will be described in which a segment signal is applied to the first segment electrodes 4, 4 formed on the upper substrate 1 for display. In this case, each common electrode 10, 11 formed on the lower substrate 2 has a phase 180 degrees shifted from each other, and the missing portions 10a, 1 of one of the common electrodes 10, 11 are applied.
A common signal that is the same as the common signal applied to one of the common electrodes 10 is applied to the second segment electrodes 5, 5 to compensate for the missing portions 11a, 11a of the other common electrode 11. The same common signal as that applied to the other common electrode 11 is applied to the electrodes 5, 5. In addition,
It is sufficient to apply the common signal to the second segment electrodes 5, 5 only to those located at positions facing the first segment electrodes 4, 4. On the other hand, to each of the common electrodes 8 and 9 formed on the upper substrate 1, a shielding signal having a potential difference smaller than the threshold voltage of the liquid crystal with respect to the common signal is applied. Here, since the thin film insulating layer 6 is interposed between the first segment electrodes 4, 4 and the common electrodes 8, 9, this is equivalent to connecting a large capacity capacitor. , these common electrodes 8,
If the potential difference between the first segment electrode 9 and the first segment electrodes 4, 4 is large, a large current will flow through the equivalent capacitor, resulting in large power loss. Therefore, as the shielding signal, a signal having a potential difference of about 1/2 of the threshold voltage with respect to the common signal is used.
Therefore, each common electrode 1 on the lower substrate 2 side
When a common signal is applied to the second segment electrodes 5, 5 that compensate for the missing parts 10a, 11a and the missing parts 10a, 11a, they all work as common electrodes for the first segment electrodes 4, 4 on the upper substrate 1 side. As a result, a display pattern corresponding to the shape of the first segment electrodes 4, 4 to which the segment signals are applied is displayed. In this case, since the above-mentioned shielding signal is applied to each common electrode 8, 9 on the upper substrate 1 side, the unnecessary portions of the first segment electrodes 4, 4 and their leads 4a,
The electric field between 4a and the lower substrate 2 is canceled by the common electrodes 8 and 9, so that the actually displayed pattern is shaped in the effective area of the first segment electrodes 4 and 4. A corresponding pattern is obtained.

In addition, the second segment electrode 5 on the lower substrate 2 side,
When displaying is performed by applying a segment signal to 5, each common electrode 8, 9 on the upper substrate 1 side and the first segment electrode 4, which compensates for the missing portions 8a, 9a of each common electrode 8, 9. It is sufficient to apply a common signal whose phase is shifted by 180 degrees to each of 4 and 4, and to apply a shielding signal as described above to each common electrode 10, 11 on the lower substrate 2 side, thereby applying a segment signal. A display pattern corresponding to the shape of the effective area of the second segment electrodes 5, 5 is displayed.

That is, in principle, the liquid crystal display device of this embodiment has a plurality of groups of dynamic drive segment electrodes 4, 4 on opposing surfaces of a pair of substrates 1, 2 which are arranged opposite to each other with a liquid crystal in between. and 5, 5, and a plurality of dynamic drive common electrodes 8, 9 and 10, 11 for segment electrodes 5, 5 and 4, 4 formed on the other substrate 2, 1.
is formed so that two types of display can be performed with one display layer. In the liquid crystal display device of this embodiment, each of the common electrodes 8,
9, 10, and 11 are respectively used as shielding electrodes that cover the unnecessary parts of the segment electrodes 4, 4, and 5, 5 on their own substrate side, and the leads 4a, 4a, and 5a, 5a, and these common electrodes 8, 9, and 10. ，
11 is formed except for the effective area of each segment electrode 4, 4 and 5, 5 on the own substrate side, and the missing portion 8 of these common electrodes 8, 9 and 10, 11 is formed.
Since a, 9a and 10a, 11a are supplemented by using the segment electrodes 4, 4 and 5, 5 as common electrodes, all indications are free from unnecessary indications such as lead shapes. There is no
Moreover, the pattern is displayed in its perfect form with no chips. Furthermore, in this embodiment, the shielding signal supplied to the common electrode is approximately 1/1/1 of the threshold voltage.
Since the signal has a potential difference of 2, the potential difference between the segment electrode and the common electrode formed on one substrate becomes small, and the current flowing through the equivalent capacitor becomes small, reducing power loss and power consumption. Reduced.

In addition, in the above embodiment, each segment electrode 4, 4
and 5, 5 are formed slightly larger than the actual display pattern, but these segment electrodes 4, 4
and 5, 5 may be made to have the same shape as the actual display pattern, and the entire area thereof may be used as an effective area. Missing parts 8a, 9a
Then, the edges of 10a and 11a may be aligned. Further, in the above embodiment, a drive unit driven at 1/2 duty was shown, but this is not limited to a drive unit driven at 1/2 duty.

Note that this liquid crystal display device may be of a twisted nematic type, a guest-host type, or any other type.

As described above, in this invention, each of the plurality of common electrodes has a missing portion in a portion corresponding to the entire display pattern formed by the segment electrodes formed in the lower layer, so that the display pattern formed by one segment electrode is divided into a plurality of common electrodes. Since they do not overlap with the common electrode, it is possible to provide two layers of dynamic drive electrodes on each of the inner surfaces of the opposing substrates of a pair of opposing substrates, allowing many complex patterns to be displayed and driven with a small number of terminals. In addition, since the shielding signal is a signal having a potential approximately half the threshold voltage, power loss can be reduced and power consumption can be reduced.

[Brief explanation of drawings]

The drawings show one embodiment of the invention.
The figure is a longitudinal side view, FIG. 2 is a bottom view of the upper substrate, and FIG. 3 is a plan view of the lower substrate. DESCRIPTION OF SYMBOLS 1... Upper substrate, 2... Lower substrate, 3... Seal material, 4, 5... Segment electrode, 6, 7... Insulating layer, 8, 9, 10, 11... Common electrode.

Claims (1)

[Claims] 1 A plurality of dynamic drive segment electrodes and an insulating film are provided on each inner surface of a pair of substrates that are arranged opposite to each other with a liquid crystal interposed therebetween, and a plurality of dynamic drive segment electrodes that face the dynamic drive segment electrodes formed on the opposing substrates are provided. common electrodes for dynamic driving are sequentially stacked, and each of the plurality of common electrodes for dynamic driving has a missing portion in a portion corresponding to the entire display pattern formed by the segment electrode for dynamic driving formed in the lower layer, A segment signal for performing a display operation is supplied to the dynamic drive segment electrode of one substrate, a common signal is supplied to both the dynamic drive segment electrode and the dynamic drive common electrode of the other substrate, and
A liquid crystal display device characterized in that a shielding signal having a potential difference of approximately 1/2 of a threshold voltage of the liquid crystal with the common signal is supplied to the dynamic drive common electrode of the one substrate.