JPH08152648A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: To provide a liquid crystal display device which has high quality and high reliability. CONSTITUTION: A substrate for scanning where transparent electrodes 1 are arrayed and a signal substrate where transparent electrodes 3 are arrayed are stuck together across liquid crystal. Further, this device is equipped with an IC 2 for scanning-side driving which applies a voltage to the respective transparent electrodes 1, and each output part of the IC 2 for scanning-side driving is branched; and one branch output part is electrically connected to one end of a transparent electrode 1 and the other branch output part is electrically connected to the other end of the transparent electrode 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device which is matrix-driven based on a voltage averaging method.

[0002]

2. Description of the Related Art As a matrix driving method, there is a so-called "voltage averaging method" for averaging voltages at half-selected points and non-selected points. According to this voltage averaging method, an operation margin is taken into consideration. The most effective time division number N and drive bias number a
And the case where the expression a = √N + 1 is satisfied, the display contrast becomes the best.

FIG. 4 shows a display wiring structure of a simple matrix type liquid crystal display device A using the voltage averaging method. Reference numeral 1 is a transparent electrode arranged on a scanning substrate.
A scanning side driving IC 2 is connected to the. Further, the signal side driving IC 4 is similarly connected to the transparent electrode 3 arranged on the signal substrate.

According to the liquid crystal display device A having the above structure, the wiring resistance of the scanning transparent electrode 1 is large, which causes a problem that a tailing phenomenon, so-called crosstalk, occurs on the image surface. The occurrence of this crosstalk becomes remarkable as the duty increases, and further tends to occur in the transparent electrode 1 far from the scanning side driving IC 2.

In order to solve such a problem, in the conventional simple matrix type liquid crystal display device, the scanning side driving IC 2 is not arranged only on one side of the transparent electrode 1 arranged on the scanning substrate, but the transparent electrode is formed. A similar scanning-side driving IC 2 is arranged at the other end of 1 to drive the two scanning-side driving ICs 2 in synchronization with each other.

[0006]

However, in the above-mentioned liquid crystal display device, it was possible to prevent crosstalk, but on the other hand, expensive scanning side driving ICs 2 must be used in many cases, and Cost reduction is desired.

Moreover, since many scanning-side driving ICs 2 are arranged other than the display screen, the external dimensions become large, and there is a problem in that the market needs for miniaturization in recent years are not met.

Therefore, it is an object of the present invention to provide a low-cost, high-quality and small-sized liquid crystal display device in which the number of scanning-side driving ICs used is reduced to reduce the manufacturing cost while preventing crosstalk.

[0009]

[Means for Solving the Problems] First invention (Claim 1)
In the liquid crystal display device, the scanning substrate in which a plurality of transparent electrodes are arranged and the signal substrate in which a plurality of transparent electrodes are arranged are pasted through a liquid crystal so that both transparent electrode arrays are orthogonal to each other. In addition, a driving IC is provided to apply a voltage to each transparent electrode on the scanning substrate, and the driving I
It is characterized in that each output portion of C is branched and each is electrically connected to one end and the other end of the transparent electrode.

A liquid crystal display device according to a second invention (claim 2) is the liquid crystal display device according to the first invention, in which one of the transparent electrodes has one end or the other end farther from the driving IC.
It is characterized in that the branch output section is electrically conductive through an FPC (flexible cable).

[0011]

In the liquid crystal display device of the first invention, in the scanning side driving IC, the output portion provided corresponding to each transparent electrode is branched, and one branch output portion is connected to one end of the transparent electrode and the other end. Since the branch output part of is electrically connected to the other end of the transparent electrode and voltage is applied from both ends, the resistance value of the transparent electrode itself apparently decreases, which causes the rise and fall of the voltage applied to the liquid crystal. Becomes steep,
As a result, crosstalk does not occur.

Moreover, since the number of scanning side driving ICs used is half that of the conventional one, the manufacturing cost is reduced accordingly.

In the liquid crystal display device according to the second aspect of the present invention, the scanning side driving IC at one end or the other end of the transparent electrode.
Since the FPC is electrically connected to the branch output section in the far side, the flexibility of the FPC allows easy connection, and no extra space is required, so that a small liquid crystal display device can be provided. In addition, the conductor of the FPC has a lower resistance value (1Ω or less) than the transparent electrode, so that the rise and fall of the voltage applied to the liquid crystal becomes much steeper and crosstalk does not occur.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The first invention will be described below with reference to FIG. 1 and the second invention with reference to FIG. FIG. 1 shows a basic configuration of the liquid crystal display device B, and FIG. 2 shows a specific configuration of the liquid crystal display device B. The same parts as those in FIG. 4 are designated by the same reference numerals.

In the liquid crystal display device B shown in FIG. 1, the transparent electrodes 1 arranged on the scanning substrate and the transparent electrodes 3 arranged on the signal substrate are arranged so as to be orthogonal to each other. , Is connected to the signal side driving IC 4 as is conventional. A branch portion 5 is provided at each output portion of the scanning side driving IC 2, one branch output portion of the branch portion 5 is electrically conductive to one end of the transparent electrode 1, and the other branch output portion is the other of the transparent electrode 1. Conductive on the edges.

Thus, the liquid crystal display device B according to the first aspect of the present invention.
According to the method, since the voltage is applied from both ends of the transparent electrode 1, the resistance value of the transparent electrode 1 apparently decreases, and the rise and fall of the voltage applied to the liquid crystal becomes steep, which causes crosstalk. Since the problem does not occur, the crosstalk problem can be solved without using an extra scanning side driving IC, so that the manufacturing cost can be reduced.

In the liquid crystal display device B having the above structure, one of the one ends or the other end of the transparent electrode 1 for driving the scanning side I is used.
There are various kinds of conductors as means for connecting to the side far from C2, and there are, for example, an FPC and a printed circuit board.

In the next second invention, the case of conducting by FPC will be described in detail. According to the liquid crystal display device B of FIG. 2, 6 is a signal substrate and 7 is a scanning substrate, both of which are transparent glass substrates. Transparent electrodes 3 and 1 are arranged on the inner surfaces of the substrates 6 and 7, respectively, and a liquid crystal is sealed between the substrates 6 and 7 by a sealant to form a display region 8. Further, the printed circuit board 9 is arranged on the scanning substrate 7 so that the end surfaces thereof face each other, and the printed circuit board 9 has a multilayer wiring structure in which one or more wiring layers are formed inside the substrate. A plurality of scan side driving ICs 2 are arranged on the printed circuit board 9.
A signal side drive IC 4 is mounted on the signal board 6 (not shown).

The printed circuit board 9 is provided with an output section of the scanning side driving IC 2 corresponding to each transparent electrode 1, and each output section is branched to the front and back of the printed circuit board 9 to form a terminal. are doing. The terminal on the front side is electrically conductive with one end of the transparent electrode 1 by the FPC 10 through the anisotropic conductive film, and the terminal on the back side is FPC 11 through the anisotropic conductive film.
Therefore, it is conductive with the other end of the transparent electrode 1.

Thus, the liquid crystal display device B according to the second aspect of the present invention.
According to the above, since the FPC 11 is used as a means for connecting to the end of the transparent electrode 1 far from the scanning side driving IC 2,
The flexibility of the FPC 11 enables easy connection, eliminates the need for an extra space, and enables size reduction.

The inventor manufactured a liquid crystal display device B of 640 dots × 480 dots (1/240 duty) and conducted a crosstalk evaluation test. This evaluation test will be described with reference to FIG. 3, which shows 640 dots × 48.
A display area 8 of 0 dots was shown, and a full lighting display was performed on the area a (240 dots × 240 dots) of the panel center, and the occurrence state of crosstalk was tested by optical transmittance.

That is, since the crosstalk occurs in the area b (120 dots × 240 dots) below the area a, the transmittance in this area b is displayed by the brightness (b), and further crosstalk occurs. The transmittance in the area c (120 dots × 200 dots) adjacent to the area b is displayed with the brightness (c), and the ratio (b) / (c) between the brightness (b) and the brightness (c) is displayed. The larger the value, the smaller the crosstalk occurrence.

Further, the FPC 11 was removed and the conventional liquid crystal display device A was formed, and the same test was conducted.

Table 1 shows the above experimental results.

[0025]

[Table 1]

As is clear from the results shown in Table 1, the liquid crystal display device B of the present invention is superior to the conventional liquid crystal display device A in that crosstalk does not occur.

The present invention is not limited to the above embodiments, and various modifications and improvements can be made without departing from the scope of the present invention.

[0028]

As described above, in the liquid crystal display device of the first invention, in the scanning side driving IC, the output section provided corresponding to each transparent electrode is branched, and one branch output section is connected to the transparent electrode. Since the other branch output section is electrically connected to the other end of the transparent electrode at one end and voltage is applied from both ends, the rise and fall of the voltage applied to the liquid crystal becomes sharp, which causes crosstalk. Can be eliminated and the number of scan side driving ICs used can be reduced to reduce the manufacturing cost. As a result, a low cost, high quality and small size liquid crystal display device can be provided.

In the liquid crystal display device according to the second aspect of the present invention, the scanning side driving IC at one end or the other end of the transparent electrode.
Since the branch output section is electrically conductive by the FPC to the side away from, it is possible to easily connect due to the flexibility of this FPC, and it is possible to eliminate unnecessary space and eliminate crosstalk. ,
A small liquid crystal display device can be provided.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of a liquid crystal display device B of an example.

FIG. 2 is a specific configuration diagram of a liquid crystal display device B of an example.

3 is a schematic diagram showing a display area of a liquid crystal display device B. FIG.

FIG. 4 is a basic configuration diagram of a conventional liquid crystal display device A.

[Explanation of symbols]

 A, B Liquid crystal display device 1, 3 Transparent electrode 2 Scanning side driving IC 4 Signal side driving IC 5 Branching section 6 Signaling board 7 Scanning board 8 Display area 9 Printed board 10, 11 FPC

Claims (2)

[Claims] 1. A scanning substrate on which a plurality of transparent electrodes are arranged, and a signal substrate on which a plurality of transparent electrodes are arranged,
Both transparent electrode arrays are bonded to each other through a liquid crystal so that they are orthogonal to each other, and further, a driving IC is provided to apply a voltage to each transparent electrode on the scanning substrate, and each output section of the driving IC is branched. The liquid crystal display device is characterized in that the transparent electrodes are electrically connected to one end and the other end, respectively. 2. The liquid crystal display device according to claim 1, wherein one of the ends of the transparent electrode or the other end of the transparent electrode, which is farther from the driving IC, is electrically connected to the branch output section via an FPC. Display device.