JPH07294948A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To prevent the appearance of a ghost by disposing transparent dummy electrodes on the inside display surfaces of glass substrates in regions where electrodes for display of a liquid crystal display panel are not disposed. CONSTITUTION:The transparent dummy electrodes 5 consisting of transparent conductors, such as ITO(Indium Tin Oxide), are formed by a thin film forming technique in the parts of the liquid crystal display panel where liquid crystals 4 exist and where electrodes 1(b) for display and connecting wirings 1(d) on the rear surface of the upper glass substrate l are not formed. The transparent dummy electrodes 5 are formed in the state of not electrically connecting the electrodes to the electrodes 1(b) for display and the connecting wirings 1(d). Electrostatic induction is induced in the transparent dummy electrodes 5 when tribostatic electricity is electrified locally in either of the parts of the upper glass substrate 1 corresponding to the upper parts of the transparent dummy electrodes 5; for example, near the positions expressed by a character B. Counter charges are induced on the front surface side thereof and the same kind of the charges on the rear surface. Particularly the same kind of the charges in the positions apart from the tribostatic electricity are diffused over a wide range and are distributed at a low density.

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,
In particular, an image caused by static electricity charged on the liquid crystal display panel due to friction between the liquid crystal display panel and other objects (for example, when carrying the liquid crystal display device in a pocket, the cloth inside the pocket). The present invention relates to a liquid crystal display device suitable for reducing obstacles.

[0002]

2. Description of the Related Art In recent years, portable information processing devices and the like have come into practical use. In this type of device, a liquid crystal display device is generally used as a display device. In this liquid crystal display device, as shown in FIG. 4, an upper glass substrate 1 and a lower glass substrate 2 which are insulators are used.
Are opposed to each other at regular intervals with the sealing material 3 interposed therebetween, and the lower surface of the upper glass substrate 1 has a display electrode 1 made of a transparent conductive film.
b, the connection wiring 1d and the orientation film 1a of the insulator covering them are formed, and the display electrode 2b, the connection wiring 2d and the orientation film 2a are similarly formed on the upper surface of the lower glass substrate 2. The liquid crystal 4 is filled in the extremely thin flat plate-shaped space formed by the upper glass substrate 1, the lower glass substrate 2, and the sealing material 3. The display electrodes 1b, the connection wirings 1d, etc. formed on the upper glass substrate 1 are specifically as shown in FIG. 5, for example.
That is, on the lower surface of the upper glass substrate 1, display electrodes 1b for matrix display or segment display and connection wirings 1d for connecting these display electrodes 1b and a display drive circuit are formed by a film forming technique.

[0003]

By the way, a small-sized information processing apparatus equipped with the liquid crystal display device as described above is often carried in a pocket or bag and used at a destination. In general, when carrying such a device, the upper glass substrate 1 of the liquid crystal display device and the cloth or the like inside the pocket or the bag rub against each other. Depending on the case, the upper glass substrate 1 of the liquid crystal display device is charged with a relatively large amount of static electricity due to friction (which may be positive or negative depending on the friction partner, but will be referred to as friction static electricity below). There is.

In the above case, in the display electrode 1b formed on the upper glass substrate 1, electrostatic induction based on friction static electricity generated on the outer surface of the upper glass substrate 1 causes
A charge opposite to the above-mentioned frictional static electricity (hereinafter referred to as an opposite charge) is induced on the upper surface side (that is, a contact surface side with the upper glass substrate 1), and a charge of the same kind as the above-mentioned frictional static electricity (hereinafter referred to as a same kind of charge) is induced on the lower surface side. ) Is induced, this homogeneous charge is
Since it also diffuses into the wiring connected to the display electrode 1b and the drive circuit section connected by this wiring, the distribution density of this charge on the lower surface side of the display electrode 1b becomes extremely low. That is, in the display electrode 1b,
It can be considered that only the opposite charge is distributed in the same amount as the triboelectric static electricity distributed in the upper glass substrate 1 in the portion above the display electrode 1b. Therefore, the above-mentioned triboelectricity is canceled out by the opposite electric charges, and in the portion directly below the display electrode 1b, that is, the portion sandwiched between the display electrode 1b and the display electrode 2b in FIG. The electric field is negligible, and the liquid crystal 4 in that portion is not substantially affected by the above-mentioned frictional static electricity.

However, a portion where the conductor corresponding to the display electrode 1b does not exist (for example, the letters A ₁ and A ₂ in FIG. 4).
Vicinity of the in indicated are located, i.e. the portion) becomes below the position indicated by the letter a ₁ ~a ₅ in FIG. 5, the opposite charges are not generated to offset the friction static electricity, a relatively large due to the tribostatic An electric field is generated. Then, the alignment state of the liquid crystal 4 is disturbed by this electric field, and as a result, an unintended display (hereinafter referred to as a ghost) appears. The appearance of this ghost often causes the user to mistakenly think that the liquid crystal display panel is cracked or the liquid crystal is leaked.

The present invention has been made in view of the above circumstances, and a liquid crystal display device in which the alignment state of the liquid crystal is prevented from being disturbed by static electricity charged on the outer surface of the liquid crystal display panel and a ghost does not appear. For the purpose of providing.

[0007]

In order to achieve the above-mentioned object, the invention according to claim 1 relates to display on an inner surface of a glass substrate in a region of a liquid crystal display panel where a display electrode is not provided. A transparent dummy electrode is provided instead. In order to achieve the above object, the invention according to claim 2 provides a means for further connecting the transparent dummy electrode according to the invention according to claim 1 to a display drive circuit.

[0008]

The invention according to claim 1 is as follows. That is, when frictional static electricity is charged on the outer surface of the liquid crystal display panel, in a region where the display electrode is not disposed, electrostatic induction is generated by the transparent dummy electrode disposed in this region based on the frictional static electricity in this region. Get up. By this electrostatic induction,
Opposite charges are induced on the upper surface side of the transparent dummy electrode, and similar charges are induced and distributed on the lower surface side. The electric field due to the opposite charges cancels the electric field due to the triboelectricity. Further, since the same kind of charge is widely distributed over the entire lower surface side of the transparent dummy electrode, that is, at a low density, as compared with frictional static electricity locally distributed on the liquid crystal display panel, the liquid crystal filling portion below the transparent dummy electrode has No large electric field is applied, so that the alignment state of the liquid crystal is not disturbed. The invention according to claim 2 is as follows. That is, when frictional static electricity is charged on the outer surface of the liquid crystal display panel, the frictional static electricity is generated in the area where the display electrode is not provided, but the upper surface of the transparent dummy electrode is the same as in the case of the invention of claim 1. It is canceled by the electric field due to the opposite charge generated on the side. Further, since the same type of charges generated on the lower surface side of the transparent dummy electrode diffuses to the wiring connected to the transparent dummy electrode and the display drive circuit side, the distribution density on the lower surface side of the transparent dummy electrode is extremely low. Becomes Therefore, only a negligible electric field is applied to the liquid crystal filling portion below the lower surface side of the transparent dummy electrode, so that the alignment of the liquid crystal is not disturbed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on the embodiments shown in the drawings. FIG. 1 shows the configuration of the first embodiment. Note that this FIG. 1 corresponds to FIG. 4 showing a conventional example, and a description will be given by assigning the same reference numerals as those in FIG. 4 to the components having the same shapes and functions as those of the components shown in FIG. Is omitted. That is, in this embodiment,
In a portion of the liquid crystal display panel where the liquid crystal 4 exists, a portion of the lower surface of the upper glass substrate 1 where the display electrodes 1b and the connection wirings 1d are not formed is ITO (Indium Tin).
Transparent dummy electrode 5 made of a transparent conductor such as oxide
Are formed by a thin film forming technique. As shown in FIG. 2 (corresponding to FIG. 5 showing a conventional example), the transparent dummy electrode 5 is in a state where it is not electrically connected to the display electrode 1b and the connection wiring 1d (that is, at a predetermined boundary portion). Are formed at intervals). The film thickness of the transparent dummy electrode 5 is approximately the same as the film thickness of the display electrode 1b and the like.

As described above, by disposing the transparent dummy electrode 5 on the lower surface of the portion of the upper glass substrate 1 where the display electrodes 1b and the like are not disposed, the upper glass substrate that is above the transparent dummy electrode 5 is disposed. When frictional static electricity is locally charged on any part of 1 in the vicinity of the position indicated by the letter B, the transparent dummy electrode 5 is generated by the frictional static electricity.
Then, electrostatic induction occurs, and the opposite charge is induced on the upper surface side of the transparent dummy electrode 5, and the same kind of charge is induced on the lower surface side by the same amount as the frictional static electricity. Then, both the electric charges, especially the same-type electric charges induced at a position away from the triboelectricity, are diffused in a wider range than the triboelectricity and distributed at a low density. Therefore, the electric field due to frictional static electricity generated near the position B is canceled by the electric field due to the opposite charge, and only the weak electric field due to the same kind of charge acts in the vicinity of the position indicated by the letter C corresponding to the position B of the liquid crystal 4 filling portion. It will be. That is, the electric field to disturb the orientation is not applied to the liquid crystal 4 in the vicinity of the position C, and the liquid crystal 4 in the relevant portion maintains the original orientation state, and the ghost does not appear.

Next, a second embodiment will be described. This embodiment has the same configuration as that of the first embodiment with respect to the disposition of the transparent dummy electrode 5 and the like. However, in FIG.
(Corresponding to FIG. 2 for the embodiment of FIG. 2), a plurality of transparent dummy electrodes 5 formed in each portion where the display electrode 1b and the connection wiring 1d are not arranged are connected by a connection line 5d or the like. The transparent dummy electrode 5 which is an electrically integrated conductor (that is, a conductor which always has the same potential) and which is integrated in this way is connected to the liquid crystal through the connection line 5b connected at the connection point 5a. It is connected to any part of the display drive circuit of the display device.

In the present embodiment having the above-described structure, when friction static electricity is charged in the area of the liquid crystal display panel where the display electrode is not provided and the transparent dummy electrode is provided, the friction The electric field in the liquid crystal filling portion due to static electricity is canceled by the electric field due to the opposite charges generated on the upper surface side of the transparent dummy electrode 5 as in the case of the first embodiment, and the lower surface side of the transparent dummy electrode 5 is canceled. The electric field of the same type generated in the above-mentioned field diffuses to the other transparent dummy electrode 5 via the connection line 5d and the like, and to the display drive circuit side via the connection line 5b. For this reason, the distribution density of similar charges on the lower surface side of the transparent dummy electrode 5 located below the portion of the upper glass substrate 1 charged with frictional static electricity becomes negligibly low, and the lower surface side of the transparent dummy electrode 5 on the lower surface side of the transparent dummy electrode 5 is neglected. The electric field applied to the liquid crystal filling portion is smaller than that in the first embodiment. Therefore, the orientation of the liquid crystal in the liquid crystal filling portion is not disturbed at all, and the ghost does not appear.

The transparent dummy electrode 5 is connected to the connection line 5b.
A predetermined potential is applied to the transparent dummy electrode 5 by the display driving circuit by connecting the transparent dummy electrode 5 to the display driving circuit. However, the transparent dummy electrode 5 and other portions (for example, the display electrode 2b of the lower glass substrate 2) are , Connection wiring 2d
Or the ground) is sufficiently far away,
The capacitance between the transparent dummy electrode 5 and the other portions is extremely small, and the drive voltage applied to the transparent dummy electrode 5 does not affect the alignment of liquid crystal molecules.

In the second embodiment, the upper glass substrate 1
A plurality of transparent dummy electrodes 5 formed on the lower surface of the are connected by a connection line 5d to form an electrically integrated conductor, and then the integrated transparent dummy electrode 5 is connected by a connection line 5b to a display drive circuit. The transparent dummy electrode 5
Of course, each of these may be connected to the display drive circuit via a connection line.

[0015]

According to the first aspect of the present invention, there is provided a liquid crystal display device in which a transparent dummy electrode not involved in display is provided on the inner surface of the glass substrate in a region of the liquid crystal display panel where the display electrode is not provided. The invention according to claim 2 relates to a liquid crystal display device in which the transparent dummy electrode according to the invention according to claim 1 is further connected to any part of a display drive circuit. Also according to the invention, a liquid crystal display device in which the alignment state of the liquid crystal in a portion of the liquid crystal display panel where the display electrodes are not provided is prevented from being disturbed by static electricity charged on the outer surface of the liquid crystal display panel and a ghost does not appear. It is possible to provide.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing an arrangement state of transparent dummy electrodes and the like on the upper glass substrate of the above embodiment.

FIG. 3 is a diagram showing an arrangement state of transparent dummy electrodes and the like on an upper glass substrate of a second embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a conventional example.

FIG. 5 is a diagram showing an arrangement state of display electrodes and the like on the upper glass substrate of the conventional example.

[Explanation of symbols]

 1 Upper Glass Substrate 1a, 2a Alignment Film 1b, 2b Display Electrode 1d, 2d Connection Wiring 2 Lower Glass Substrate 3 Sealant 4 Liquid Crystal 5 Transparent Dummy Electrode 5a Connection Point 5b, 5d Connection Line A Position

Claims (2)

[Claims] 1. A liquid crystal display device comprising a liquid crystal display panel in which a liquid crystal is sealed between an upper glass substrate and a lower glass substrate, each of which has a display electrode or the like and is opposed to the liquid crystal display panel. A liquid crystal display device characterized in that a transparent dummy electrode not involved in display is provided on the inner surface of a glass substrate in a region where a display electrode is not provided. 2. The liquid crystal display device according to claim 1, wherein the transparent dummy electrode is connected to any part of a display drive circuit of the liquid crystal display device.