JP2002214635A - Liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a dielectric breakdown of liquid crystal display due to the discharging of accumulated static electricity from the tip part, etc., of a terminal for connection. SOLUTION: The terminal 9 for connection is formed having its tip extended to the end side of the outer periphery of a TFT substrate 3 and a high- resistance area 11 of high electric resistance is formed from the tip to the inside of the TFT substrate 3 by specific length(L). Consequently, even if a metal part (not illustrated), etc., of an external carrying device, a chucking member, etc., is brought into contact with or put close to the end side of the outer periphery of the TFT substrate 3, the abrupt discharging of static electricity accumulated in the TFT substrate 3, etc., so far can be avoided.

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 having a connection terminal used for connection to a liquid crystal drive circuit.

[0002]

2. Description of the Related Art Generally, as shown in FIGS. 9 and 10, two substrates 103 and 105 having pixel electrodes (not shown) in an effective display area 101 have a gap as shown in FIGS. A liquid crystal layer (not shown) is sandwiched between gaps which are disposed so as to face each other, and the periphery thereof is sealed with a sealing material 110 or the like, thereby forming a main part of the liquid crystal display panel. In the liquid crystal display panel, each pixel is formed by opposing pixel electrodes and a liquid crystal layer sandwiched therebetween, and a liquid crystal driving circuit (not shown) is connected to drive each pixel. A connection terminal 109 for making an electrical connection to the liquid crystal drive circuit is provided between the outside and the edge of the effective display area 101 on at least one of the two substrates 103 and 105. Is provided in the part.

More specifically, for example, in the case of a small liquid crystal display device used in a viewfinder of a video camera, a pocket type liquid crystal television, or the like, the flexible cable 1 is connected to the connection terminal 109 of the liquid crystal display device.
One end of 23 is connected via an anisotropic conductive film or the like (not shown). Since a liquid crystal driving circuit is connected to the other end of the flexible cable 123, the liquid crystal display device is connected to the liquid crystal driving circuit via the flexible cable 123.

[0004]

However, since at least one of the two substrates of the liquid crystal display device is made of a material such as glass or transparent plastic,
Liquid crystal displays tend to be charged with static electricity. Therefore, the liquid crystal display panel is chucked by the rubbing processing device when the substrate on which the connection terminals 109 are formed is transported by the transport device during the manufacturing process, or in the step of performing the rubbing alignment process on the alignment film (not shown). In such a case, the cracking member of the transfer device or the chucking member made of metal of the rubbing treatment device comes into contact with or close to the connection terminal 109 provided on the edge of the liquid crystal display panel, and the liquid crystal display panel is charged until then. Static electricity was suddenly discharged,
There is a problem in that a TFT (Thin Film Transistor) element or a pixel electrode inside the liquid crystal display panel connected to the connection terminal 109 may be electrostatically damaged.

In particular, the distal end of the connection terminal 109 has a three-dimensional shape, for example, the end face and the upper surface are in contact with each other at a substantially right angle to form a ridge line. It's easy to do. For this reason, especially the connection terminal 1
At the tip of 09, there is a high probability that the charged static electricity will be discharged, and the occurrence of electrostatic destruction or damage during transport or rubbing treatment will be promoted, making it even more difficult to eliminate it. Had become.

The present invention has been made in view of the above problems, and has as its object to solve the problem of electrostatic breakdown of a liquid crystal display device caused by the discharge of charged static electricity from the tip of a connection terminal. Is to do.

[0007]

In a liquid crystal display device according to the present invention, two substrates having pixel electrodes arranged in an effective display area are opposed to each other with a gap therebetween, and a liquid crystal layer is sandwiched in the gap. Each pixel is formed by opposing pixel electrodes and a liquid crystal layer sandwiched therebetween, and two connection terminals for electrical connection to a liquid crystal drive circuit for driving each pixel are provided. A liquid crystal display device disposed outside an effective display area on at least one of the substrates, wherein the connection terminal is formed such that a tip thereof reaches an outer peripheral edge of the substrate. The region extending a predetermined length from the front end toward the inside of the substrate is set as a region having high electric resistance.

Further, another liquid crystal display device according to the present invention comprises:
Two substrates having pixel electrodes disposed in an effective display area are disposed to face each other with a gap therebetween, and a liquid crystal layer is sandwiched between the gaps. Each pixel is composed of the opposing pixel electrodes and the liquid crystal layer sandwiched therebetween. Are formed, and connection terminals for electrical connection to a liquid crystal drive circuit for driving each pixel are arranged outside the effective display area on at least one of the two substrates. A liquid crystal display device, wherein a tip of the connection terminal near an edge of the substrate is set so as to be located inwardly over a predetermined distance from the edge of the substrate. is there.

[0009] In the liquid crystal display device according to the present invention, the connection terminal is formed so that the tip thereof reaches the outer peripheral edge of the substrate, and extends from the tip toward the inside of the substrate over a predetermined length. The region is set to a region having a high electric resistance so that even if it comes into contact with a metal part such as an external transfer device or a chucking member, static electricity that has been charged so far does not suddenly discharge.

In another liquid crystal display device according to the present invention, in order to prevent the front end or front end face of the connection terminal from coming into contact with a metal part such as an external transfer device or a chucking component, the connection terminal is not used. Is set so that the front end near the edge of the substrate is recessed inward over a predetermined distance from the edge of the substrate.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[First Embodiment] FIG. 1 shows a schematic configuration of a liquid crystal display device according to a first embodiment of the present invention, and FIG. This is extracted and shown. FIG. 3 is a sectional view showing a schematic configuration of the liquid crystal display device.

This liquid crystal display device has a schematic structure of a TFT active matrix type, and a pixel electrode (not shown) and a TF connected to the pixel electrode are provided in an effective display area 1.
TFTs (not shown) arranged in a matrix
The substrate 3 and the opposing substrate 5 on which the common electrode is formed are sealed to each other with a sealant 10 or the like so as to be opposed to each other with a gap therebetween. The liquid crystal layer 7 is sandwiched in the gap, and the opposing pixel electrode is Each pixel is formed by the common electrode and the liquid crystal layer 7 sandwiched therebetween. A connection terminal 9 for making an electrical connection to a liquid crystal drive circuit (not shown) for driving each pixel is provided outside the effective display area 1 on the TFT substrate 3.

The connection terminal 9 has a tip end on the TFT substrate 3.
2 is formed so as to reach the outer peripheral edge of the TFT substrate 3, and a predetermined length (FIG.
(Shown by L in FIG. 2) is a high resistance region 11 having a high electric resistance.

More specifically, as shown in the cross-sectional view of FIG. 4, the connection terminal 9 has a high electric resistance over a predetermined length L from the tip to the inside of the TFT substrate 3. A high-resistance region 11 made of a material is formed. The connection region 13 closer to the back (inside of the TFT substrate 3) is made of a general metal material having good conductivity or a material obtained by imparting high conductivity to a semiconductor material.

As a material having a high electric resistance for forming the high-resistance region 11, for example, a metal material such as tungsten, aluminum oxide, or titanium oxide, or a non-metal material such as carbon or epoxy resin is preferable. Can be used. The electric resistance value of the high resistance region 11 is desirably 100 to 1000 [Ω] or more. Such an electric resistance is connected to the connection terminal 9.
Even when an external metal or the like comes into contact with or comes close to the high-resistance region 11, the TFT
It is possible to prevent the static electricity charged on the substrate 3 from suddenly moving to the outside.

The connection area 13 of the connection terminal 9 is used as an original connection terminal to be connected to the flexible cable 23 or the like. An ITO (indium tin oxide) film is laminated, a copper foil, a foil made of an alloy of copper and nickel, or an aluminum foil for electric wiring is preferably used and patterned into a predetermined terminal shape. By doing so, the connection terminal 9 can be obtained.

Alternatively, in the case where the TFT substrate 3 is formed using a silicon wafer, as shown in the cross-sectional view of FIG. The material of the region over a predetermined length (L) from the tip is made of a material having a surface of at least 100 to 100.
The high resistance region 11 can be formed by altering the resistance to be 0 [Ω] or higher. More specifically, for example, a metal layer formed by depositing aluminum is patterned to form the entire connection terminal 9, and a region extending from the tip to a predetermined length is oxidized.
That portion can be used as the high resistance region 11 as described above. Alternatively, an impurity that traps free electrons of the metal material forming the entire connection terminal 9 is doped into a region extending from the tip of the connection terminal 9 over a predetermined length,
Such a portion can be used as the high-resistance region 11 or the like.

As shown in the cross-sectional view of FIG. 6, the entire connection terminal 9 is formed of a conductive material, and covers the surface of a region extending from the tip to a predetermined length. It is also possible to apply a coating material 15 made of a high-resistance material or an insulating material, and to make the portion covered with the coating material 15 a high-resistance region 11. As such a coating material 15, for example, a synthetic resin of a material having high electric resistance such as epoxy or polyester, or an insulating powder such as carbon particles dispersed in a medium having characteristics suitable for application is used. The insulating paint or the like obtained as described above can be suitably used. However, if the thickness of the coating material 15 is too large, it may hinder the joining of the flexible cable 23. Therefore, it is desirable to set the thickness to an appropriate thickness including the balance.

The high resistance region 11 as described above is connected to the connection terminal 9.
7 is electrically provided as shown in the equivalent circuit of FIG. That is, the TFT substrate 3
Since the tip of the connection terminal 9 where the electrostatic discharge phenomenon is most likely to occur is high resistance or almost insulative, the tip of the connection terminal 9 may be externally attached to the tip when transporting or processing the TFT substrate 3, for example. Even if a metal member or the like (not shown) comes into contact with or comes close to
With the electrical resistance of [Ω] or more, it is possible to reduce the rising peak voltage which causes the instantaneous movement of the electrostatic charge in a pulsed manner, thereby suppressing the rapid movement of the electrostatic charge. As a result, electrostatic breakdown of the input protection diode 21 and the TFT inside the liquid crystal display device due to the discharge of the static electricity charged on the substrate from the tip of the connection terminal 9 is reliably eliminated. Can be.

[Second Embodiment] FIG. 8 shows a portion of connection terminals in a liquid crystal display device according to a second embodiment of the present invention, which is particularly extracted.

In this liquid crystal display device, the tip of the connection terminal 92 is set so as to be recessed inward from the edge of the TFT substrate 3 over a predetermined distance (indicated by d in FIG. 8). .

The distance (d) at which the tip of the connection terminal 92 is retracted from the edge of the TFT substrate 3 is such that a metal member (not shown) of an external transport device contacts the edge of the TFT substrate 3. Even so, it is desirable to set the connection terminal 92 to a necessary and sufficient one that can surely avoid contact with the tip of the connection terminal 92. When the tip of the connection terminal 92 is retracted to avoid the movement of electrostatic charge to the outside in this way, the surface of the tip of the connection terminal 92 remains in a state of good conductivity. The distance (d) for making the tip deeper is set to be longer than the length (L) of the high resistance region when the tip is made to have high resistance as in the first embodiment. Is desirable.

As described above, the tip of the connection terminal 92 where the most electrostatic discharge phenomenon is likely to occur on the TFT substrate 3
It is provided at a position recessed from the edge of the substrate 3 so as to retreat. Accordingly, even if an external metal member or the like comes into contact with or comes close to an edge of the TFT substrate 3 during transportation or processing of the TFT substrate 3, for example, the connection terminal provided deeper than the edge. Since a metal member or the like cannot reach the tip of the connection terminal 92, static electricity charged on the TFT substrate 3 is discharged to the connection terminal 9.
By avoiding discharge from the tip of the second to the outside, electrostatic breakdown of the input protection diode 21 and the TFT inside the liquid crystal display device can be reliably eliminated.

The material for forming the high-resistance region 11 and the material for forming the connection terminals 9 and 92 shown in the above-described embodiment are some specific examples. It goes without saying that the present invention is not limited to the above.

[0026]

As described above, claims 1 to 4
According to the liquid crystal display device described in any one of the above, the connection terminal is formed such that its tip reaches the outer peripheral edge of the substrate, and has a predetermined length from the tip toward the inside of the substrate. Even if the area over the contact area comes into contact with metal parts such as external transporting devices and chucking parts, it is necessary to prevent the static electricity that had been charged up to that point from being discharged and, conversely, to prevent sudden inflow of electricity from the outside. In addition, since the electric resistance is set in the high electric resistance region, the electrostatic breakdown of the liquid crystal display device due to the static electricity charged on the substrate being discharged from the tip of the connection terminal is eliminated. It has the effect of being able to do so.

[0027] According to the liquid crystal display device of the fifth aspect, the tip of the connection terminal near the edge of the substrate is recessed inward from the edge of the substrate by a predetermined distance. Because it is set, it is possible to prevent the tip of the connection terminal from coming into contact with metal parts such as metal parts and chucking parts of the external transfer device, and the static electricity charged on the substrate is This has the effect of eliminating electrostatic damage and deterioration of the liquid crystal display device caused by discharge from the tip of the connection terminal to a metal component such as an external transport device or chucking component.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a connection terminal portion in the liquid crystal display device according to the first embodiment of the present invention.

FIG. 3 is a sectional view of the liquid crystal display device according to the first embodiment of the present invention.

FIG. 4 is a sectional view of a portion of a connection terminal shown in FIG. 2;

FIG. 5 is a cross-sectional view showing a variation of a schematic configuration of a connection terminal portion in the liquid crystal display device according to the first embodiment of the present invention.

FIG. 6 is a diagram showing another variation of the schematic configuration of the connection terminal portion in the liquid crystal display device according to the first embodiment of the present invention.

FIG. 7 is a diagram showing an electrostatic schematic configuration of a liquid crystal display device provided with a high-resistance region at a tip end of a connection terminal by an equivalent circuit.

FIG. 8 is a diagram illustrating an extracted portion of a connection terminal in a liquid crystal display device according to a second embodiment of the present invention.

FIG. 9 is a diagram showing a schematic configuration of a conventional liquid crystal display device to which a flexible cable is connected.

FIG. 10 is a diagram illustrating an extracted portion of a connection terminal in a conventional liquid crystal display device.

[Explanation of symbols]

1: effective display area, 3: TFT substrate, 5: counter substrate, 7
... liquid crystal layer, 9, 92 ... connection terminals, 10 ... sealing material, 1
DESCRIPTION OF SYMBOLS 1 ... High resistance area, 13 ... Connection area, 15 ... Coating material

Claims (5)

[Claims] A pixel electrode disposed in an effective display area;
The substrates are disposed facing each other with a gap, a liquid crystal layer is sandwiched in the gap, and each pixel is formed by the opposed pixel electrode and the liquid crystal layer sandwiched therebetween, and each pixel is formed. A liquid crystal display device wherein a connection terminal for making an electrical connection to a liquid crystal drive circuit to be driven is disposed outside an effective display area on at least one of the two substrates. The connection terminal is formed such that a tip thereof reaches an edge of an outer periphery of the substrate, and a region extending a predetermined length from the tip toward the inside of the substrate has a high electric resistance. A liquid crystal display device characterized by being an area. 2. The liquid crystal display device according to claim 1, wherein the region having a high electric resistance is made of a material having a high electric resistance different from a conductive material of the connection terminal. 3. The liquid crystal display device according to claim 1, wherein the region having a high electric resistance is formed by changing the material of the portion to have a high resistance. 4. The liquid crystal display according to claim 1, wherein the region having a high electric resistance is formed by coating a surface of the connection terminal with a high electric resistance material or an insulating material. apparatus. 5. A method according to claim 2, wherein the pixel electrodes are arranged in the effective display area.
The substrates are disposed facing each other with a gap, a liquid crystal layer is sandwiched in the gap, and each pixel is formed by the opposed pixel electrode and the liquid crystal layer sandwiched therebetween, and each pixel is formed. In a liquid crystal display device, a connection terminal for making an electrical connection to a liquid crystal drive circuit to be driven is disposed outside an effective display area on at least one of the two substrates. The tip of the connection terminal near the edge of the substrate is
A liquid crystal display device which is set so as to be recessed inward over a predetermined distance from an edge of the substrate.