JPH03216618A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve image quality and the remedy for electrostatic breakdown and to simplify the process for production by impressing DC voltages of prescribed potentials via resistors to respective common electrodes and respective segment electrodes. CONSTITUTION:The liquid crystal display device has, for example, 200 pieces of the common electrodes and is so constituted that picture elements 3 corresponding to n-pieces, for example, 640 pieces of the segment electrodes 2 are controlled by the respective common electrodes 1. The respective common electrodes 1 and segment electrodes 2 are so formed that the DC voltages Vc of the prescribed potentials are impressed respectively via the resistors R thereto. The influence of the induction from other signals and noise is lessened in this way and the quality of display images 3 is improved. The remedy for electrostatic breakdown is improved by executing the current limitation on static electricity and further the process for cutting the terminals of signal wires which has been practiced heretofore is omitted and the process for production is simplified.

Description

[Detailed Description of the Invention] [Summary] Regarding liquid crystal display devices, the purpose of this invention is to improve image quality and prevent electrostatic damage, as well as to simplify the manufacturing process. This liquid crystal display device has a plurality of pixels sandwiched between layers, and is configured to apply a DC voltage of a predetermined potential to each of the common electrodes and each segment electrode via a resistor, respectively.

[Industrial application field]

The present invention relates to a liquid crystal display device.

In recent years, liquid crystal display devices have been used in various products including office automation equipment. Therefore, there is a need for a liquid crystal display device that has high image quality and is resistant to electrostatic damage. [Prior Art] FIG. 6 is a diagram showing an example of a liquid crystal display device.

As shown in the figure, a liquid crystal display device generally includes a plurality of pixels 3 with a liquid crystal layer sandwiched between a plurality of common electrodes 1 and segment electrodes 2 facing each other. Here, the common electrode 1 and the segment electrode 2 are, for example,
Transparent electrodes such as ITO are formed on glass plates provided on both sides of the liquid crystal layer so as to sandwich the liquid crystal layer, and polarizing plates are provided on both sides of the glass plates on which these electrodes are formed. . By controlling the pulse voltage signal applied between any common electrode 1 and segment electrode 2, the crystal direction of the liquid crystal (pixel) at the position corresponding to the common electrode 1 and segment electrode 2 is controlled. , black or white is displayed by blocking or transmitting the light passing through the polarizing plate. The pixels are arranged in a matrix (for example, 640×200 dots), and each pixel is controlled to display a predetermined image on the liquid crystal panel 6.

FIG. 7 is a diagram showing another example of a liquid crystal display device, and the liquid crystal display device shown in FIG. 6 above! (2 liquid crystal panels 6 with a 640 x 200 dot configuration) are lined up, that is, the common driver 40 is used in common, and the segment drivers are the first segment driver 5a and the second segment driver 5b to create a liquid crystal display with a 640 x 400 dot configuration. (two liquid crystal panels 6a and 6b with a 640 x 200 dot configuration).

By the way, in a liquid crystal display device, each pixel (liquid crystal load)
can be regarded as a capacitive load to the corresponding common electrode and segment electrode, respectively.

[Problem to be solved by the invention]

FIG. 8 is a circuit diagram showing an example of a conventional liquid crystal display device, and FIG. 9 is a circuit diagram showing another example of a conventional liquid crystal display device. Here, FIG. 8 corresponds to the liquid crystal display device of FIG. 6, and FIG. 9 corresponds to the liquid crystal display device of FIG. 7.

In the conventional multiple line control of a liquid crystal display device, when a multiple line 1 drive circuit is adopted, that is, as shown in FIG. When controlling the pixel 3 corresponding to 2n (for example, 128
0) Pixel 3 corresponding to segment electrodes 2a, 2b
When controlling a and 3b, no circuit measures have been taken at all to prevent mutual induction due to the circuit-coupled capacitive load (liquid crystal load) C. Therefore, the induction to the other control line (t pole) caused by the response of the capacitive load C on the liquid crystal panel side is affected by the pixels corresponding to both the side where the signal is induced and the side where the signal is induced, and the display Unevenness may occur in the image.

FIG. 10 is a diagram showing the structure of an electrode end in a conventional liquid crystal display device. As shown in the figure, in a conventional liquid crystal display device, in order to prevent electrostatic damage during the manufacturing stage, the terminals of all the common electrodes 1 and segment electrodes 2 in the liquid crystal panel 6 are short-circuited. At this point, the terminal end of the electrode is cut to connect it to a drive circuit (common driver and segment driver). Therefore, when manufacturing a liquid crystal display device, the process of cutting the end portions of the electrodes has been increased. Furthermore, conventionally, no measures have been taken to prevent electrostatic damage to liquid crystal display devices after they have been manufactured. Here, at the ends of the common electrode 1 and the segment electrode 2 in the liquid crystal panel 6, connection parts 11 and 21 are provided for connecting each common electrode and the segment electrode 2 to the corresponding common driver 4 and segment driver 5.
A power is provided.

SUMMARY OF THE INVENTION In view of the above-described problems with conventional liquid crystal display devices, the present invention aims to improve image quality and countermeasures against electrostatic damage, and to simplify the manufacturing process.

[Means to solve the problem]

FIG. 1 is a diagram showing the principle of a liquid crystal display device according to the present invention.

According to the present invention, a plurality of pixels 3 are formed by sandwiching a liquid crystal layer between a plurality of common electrodes 1 and segment electrodes 2 that face each other.
A liquid crystal display device comprising: each of the common electrodes 1;
There is also provided a liquid crystal display device characterized in that a DC voltage Vc of a predetermined potential is applied to each segment electrode 2 via a resistor R, respectively.

[For production]

According to the liquid crystal display device of the present invention having the above-described configuration,
A DC voltage Vc of a predetermined potential is applied to each common electrode 1 and each segment electrode 2 via a resistor R, respectively. As a result, it is possible to improve the quality of a displayed image by reducing the effects of induction and noise from other signals, and it is also possible to improve countermeasures against electrostatic damage by limiting the current against static electricity. Furthermore, the manufacturing process can be simplified by omitting the conventional cutting process of the end of the signal line.

〔Example〕

Embodiments of a liquid crystal display device according to the present invention will be described below with reference to the drawings.

FIG. 2 is a circuit diagram showing one embodiment of the liquid crystal display device of the present invention, and FIG. 3 is a circuit diagram showing another embodiment of the liquid crystal display device of the present invention. Here, FIG. 2 corresponds to the liquid crystal display device shown in FIG. 6, and FIG. 3 corresponds to the liquid crystal display device shown in FIG. 7.

As shown in FIGS. 2 and 6, the liquid crystal display device of this embodiment includes, for example, 200 common electrodes (common lines) 1, and each common electrode 1 has n lines (for example, 64 lines).
The pixels 3 corresponding to the segment electrodes (segment lines) 2 (0 lines) are controlled. A resistor R is connected to each common electrode 1 and each segment electrode 2, and a DC voltage Vc of a predetermined potential is applied to all the common electrodes 1 and segment electrodes 2 via the resistor R. It is designed so that

The voltage Vc applied to the common electrode 1 and the segment electrode 2 via this resistor R is set to an intermediate potential (for example, ground potential: 0 volts) between the voltage levels that drive the liquid crystal display device, as described later. be done.

Furthermore, the liquid crystal display device shown in FIGS. 3 and 7 is
The liquid crystal display device (
640 x 200 dot configuration LCD panel 6) 2
In other words, the common driver 40 is used in common, and the segment drivers are 640×4 by the first segment driver 5a and the second segment driver 5b.
00 dot configuration liquid crystal display (two 640
A liquid crystal panel (6a+6b) with a 200-dot configuration is applied, and a DC voltage Vc of a predetermined potential is applied to each common electrode 1 (1a, 1b) and each segment electrode 2a, 2b via a resistor R, respectively. It is done like this.

FIG. 4 is a waveform diagram showing an example of the driving voltage of a liquid crystal display device, and shows the common drivers 4 and 4 of FIGS. 2 and 3.
0 and control signals at the segment drivers 5, 5a, and 5b. That is, each common driver 4 (40) and segment driver 5 (5a
．． 5b) each comprising four transistors, the four
Only one of the two transistors is switched on to select a predetermined potential within the drive voltages v0 to vSO. That is, each common electrode 1 (la
, lb) are supplied with a control pulse signal having a waveform as shown in FIG. 4(a), and each segment electrode 2
(2a, 2b) are supplied with a control pulse signal having a waveform as shown in FIG. 4(b). Therefore, each common electrode 1 (la, lb) and each segment electrode 2 (2a
, 2b), a control pulse voltage having a waveform as shown in FIG. 4(c) is applied to the liquid crystal [pixel 3 (3a. A predetermined image is displayed by controlling the color to white. As described above, the voltage Vc applied to the common electrode 1 and the segment electrode 2 via the resistor R is set to an intermediate potential (for example, ground potential: 0 volts) between the voltage levels that drive the liquid crystal display device.゛ is preferable. but,
This voltage Vc does not need to be strictly controlled, and may be at a potential approximately in the middle of the voltage level that drives the liquid crystal display device. In this way, when a voltage Vc with a potential approximately midway between the drive voltage level is applied to all the common electrodes 1 and segment electrodes 2 via the resistor R, the voltage level of each common electrode 1 and segment electrode 2 is fixed. Thus, a DC load is provided to the common driver 4 and the segment driver 5. This reduces the induction to other control lines (electrodes) caused by the response of the capacitive load C on the liquid crystal panel side, and reduces the influence that occurs on pixels corresponding to both the signal-induced side and the signal-induced side. be able to. Furthermore, since this resistor R functions as a current-limiting resistor against static electricity applied to each common electrode 1 and segment electrode 2, it is possible to improve electrostatic breakdown resistance. Here, if the resistance value of the resistor R is too large, it will not be possible to sufficiently reduce the influence of the capacitive load C and improve the electrostatic breakdown characteristics. If it is set to a small value, it will affect the control signals supplied to the common electrode 1 and the segment electrodes 2, making it impossible to perform high-speed operation and increasing power consumption. Therefore, the resistance value of the resistor R needs to be set in consideration of the above.

FIG. 5 is a diagram showing the structure of the electrode end portion in the liquid crystal display device of the present invention. Compared to the structure of the electrode end portion in the conventional liquid crystal display device shown in FIG. 10, in the conventional liquid crystal display device, all common electrodes 1 and segments in the liquid crystal panel 6 are The end of the electrode 2 is short-circuited, and in the final stage, the end of the electrode is cut to connect to the drive circuit. However, in the liquid crystal display device of this embodiment, resistors R are provided at the ends of all the common electrodes 1 and segment electrodes 2 formed on the liquid crystal panel. That is, in the liquid crystal panel 6, one end of the resistor R is connected to the outside of the connection parts l1 and 21 provided at the ends of the common electrode 1 and the segment electrode 2, and the resistor R
The predetermined voltage Vc is commonly applied to the other end. This effectively prevents electrostatic damage during the manufacturing stage. Furthermore, the resistor R can prevent electrostatic damage even in the manufactured liquid crystal display device, that is, the liquid crystal display device actually used.

〔Effect of the invention〕

As detailed above, the liquid crystal display device according to the present invention includes:
By applying a DC voltage of a predetermined potential to each common electrode and segment electrode through a resistor, it is possible to improve image quality and countermeasures against electrostatic damage, and to simplify the manufacturing process.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the principle of a liquid crystal display device according to the present invention, FIG. 2 is a circuit diagram showing an embodiment of the liquid crystal display device according to the present invention, and FIG. 3 is a diagram showing another embodiment of the liquid crystal display device according to the present invention. A circuit diagram showing an example; FIG. 4 is a waveform diagram showing an example of the driving voltage of a liquid crystal display device; FIG. 5 is a diagram showing the structure of an electrode end in a liquid crystal display device of the present invention; FIG. 6 is a liquid crystal display device FIG. 7 is a diagram showing another example of a liquid crystal display device, FIG. 8 is a circuit diagram showing an example of a conventional liquid crystal display device, and FIG. 9 is another example of a conventional liquid crystal display device. FIG. 10 is a diagram showing the structure of an electrode end in a conventional liquid crystal display device. (Explanation of symbols) 1.1a. 1b... common electrode, 2.2a. 2b... segment electrode, 3, 3a. 3b
... Pixel, 4.40... Common driver, 5.5a, 5b... Segment driver, 6... Liquid crystal panel, C... Capacitive load (liquid crystal load), R... Resistor, Vc...DC voltage. Diagram showing the principle of the liquid crystal display device according to the present invention. Figure 1. R...Resistor. Circuit diagram showing an embodiment of the liquid crystal display device according to the present invention. Figure 2. Structure of the electrode end in the liquid crystal display device of the present invention. FIG. 5 shows an example of a liquid crystal display device.FIG. 6 shows an example of a liquid crystal display. FIG. 7 is a circuit diagram showing another example of a conventional liquid crystal display device. FIG. 8 is a circuit diagram showing another example of a conventional liquid crystal display device. FIG. 9 is a circuit diagram showing another example of a conventional liquid crystal display device. FIG. 9 is a circuit diagram showing another example of a conventional liquid crystal display device. Figure 10 shows the structure of the end of the electrode in the display device.

Claims (1)

[Claims] 1. A plurality of pixels (3) with a liquid crystal layer sandwiched between a plurality of common electrodes (1) and segment electrodes (2) facing each other.
A liquid crystal display device comprising: a DC voltage (Vc) of a predetermined potential is applied to each of the common electrodes and each segment electrode via a resistor (R). . 2. Claim 1, wherein the resistor (R) is formed at an end of a common electrode and a segment electrode on a liquid crystal panel.
The liquid crystal display device described in . 3. The liquid crystal display device according to claim 1, wherein the voltage (Vc) applied to the common electrode and the segment electrode via the resistor is set to a potential intermediate between the voltage levels that drive the liquid crystal display device. .