JP3326673B2 - Liquid crystal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a liquid crystal display device. More specifically, the present invention relates to a liquid crystal display device capable of preventing display defects due to electrostatic discharge generated in electrode terminal portions.

[0002]

2. Description of the Related Art With the development of a highly information-oriented society, the field of liquid crystal display devices has made remarkable progress. However, liquid crystal display elements, especially liquid crystal display elements of the active matrix type, have low productivity, and the resulting increase in product price has hindered widespread use. One of the major factors that reduce the yield of liquid crystal display devices is an electrostatic disturbance. Electrostatic damage occurs in almost all manufacturing steps of a liquid crystal display element. In particular, the rate of occurrence due to discharge from the second transparent insulating substrate constituting the liquid crystal display element to the electrode terminals is high, which is a major problem. .

[0003] There are two typical modes of electrostatic damage caused by discharge from the second transparent insulating substrate of the liquid crystal display element to the electrode terminals. One is an obstacle peculiar to an active matrix drive type liquid crystal display element. When static electricity enters from a source electrode terminal or a gate electrode terminal, a potential difference is suddenly generated between a source and a gate of a transistor in the liquid crystal display element. The threshold voltage _Vth for operating the transistor shifts and is visually recognized as a linear defect. The other one is one in which static electricity enters from a specific electrode terminal, a part of the liquid crystal shows an alignment state different from that of the surroundings due to the electric charge, and is visually recognized as a linear defect.

As the most effective method for preventing the above-mentioned electrostatic damage, Japanese Patent Application Laid-Open No. 3-290624 discloses a method in which a gate electrode terminal and a source electrode terminal of a liquid crystal display element are connected to a low-resistance connector called a short ring. It is described that short-circuiting between the transistors causes the gate electrode and the source electrode to have the same potential, thereby preventing a shift in transistor characteristics due to static electricity and static electricity entering only a specific electrode terminal. However, this method cannot be a definitive method since the gate electrode and the source electrode cannot be kept at the same potential in the steps after the short circuit is cut.

Although a method of irradiating an ion blower during the manufacture of a liquid crystal display element to neutralize the rapid transfer of electric charges due to static electricity has been proposed, the rapid transfer of electric charges due to static electricity can be prevented in a short time. It is impossible to reconcile, and
If the ion blower is irradiated for a long period of time, the liquid crystal display element may be charged in reverse, which is not an effective method.

Further, Japanese Patent Application Laid-Open Nos. 4-198922 and 1-237523 describe a method for preventing an electrostatic failure which easily occurs between a source wiring block and a gate (common) wiring block. I have.
A dummy terminal is provided outside a terminal block used for a display purpose of the liquid crystal display element, and an LSI (large scale integrated) for driving the dummy terminal and the switching element is provided.
circuit) is connected to the ground terminal provided on the outer printed circuit board via dummy wiring formed on both sides of the output electrode terminal row of the film carrier on which the film carrier is mounted to prevent static electricity damage. I have. But,
In this method, only the static electricity easily generated between the blocks can be prevented, and the static electricity failure due to the discharge from the charge near the end face of the second transparent insulating substrate cannot be prevented.

[0007]

As described above, in a conventional countermeasure against static electricity damage of a liquid crystal display element, a drive LSI and an external printed circuit board are cut after cutting a short ring (low resistance connection body) of the liquid crystal display element. A state in which a liquid crystal display element is connected to the circuit and the potential between the source electrode terminal and the gate electrode terminal of the liquid crystal display element is set to the same potential, that is, in the state where the source electrode terminal and the gate electrode terminal are not short-circuited. As a means, it is not effective.

An object of the present invention is to solve such a problem and to provide a liquid crystal display device having high reliability and high productivity.

[0009]

According to the present invention, there is provided a liquid crystal display device comprising: a transparent insulating substrate; a second transparent insulating substrate having a size corresponding to an image display area; Consisting of a liquid crystal material sandwiched between the transparent insulating substrate, on the transparent insulating substrate, a plurality of gate electrode terminals disposed in parallel and at equal intervals, orthogonal to the gate electrode terminal, And, a plurality of source electrode terminals respectively disposed in parallel and at equal intervals, a gate wiring and a source wiring formed respectively connected to the gate electrode terminal and the source electrode terminal, the gate wiring and the Switches formed at the intersections with the source wiring
A switching element, and a display electrode formed in each region divided by the gate wiring and the source wiring, wherein the transparent insulating substrate and the second transparent insulating substrate have similar shapes. A liquid crystal display element which is disposed so as to be overlapped with the second transparent insulating substrate, wherein the transparent insulating substrate and the second transparent insulating substrate are overlapped from an end of the transparent insulating substrate. The gate electrode terminal and the source electrode connected to the gate line and the source line, respectively, for inputting a driving signal from the outside on an end region on the transparent insulating substrate up to an end of the substrate; The terminals form one gate electrode terminal block and one source electrode terminal block respectively with the number of electrode terminals included in one film carrier on which the LSI is mounted. An insulating film is stacked on each of the upper layers of the gate electrode terminal block and the source electrode terminal block, and a source conductive film is further formed on the insulating film in the upper layer and perpendicularly to the source electrode terminal block and across the source electrode terminal block. formed, perpendicular to the gate electrode terminal block, and forming a gate conductive layer over the gate electrode terminal block, Oyo the source conductive layer
And the gate conductive film, the source terminal block and the gate end.
Of each film carrier connected to the child block
Area between the end and the end of the second transparent insulating substrate
Provided range, the permeability Akiraze' after the film carrier connection
It is exposed on the edge substrate .

It is preferable that the conductive film is formed of a film under the same manufacturing conditions as a source electrode or a drain electrode for forming the switching element, in order to manufacture a liquid crystal display element at low cost.

[0011] The conductive film formed perpendicular to the gate electrode terminal row may be formed of a film under the same manufacturing conditions as the display electrode.

The conductive film is made of a film under the same manufacturing conditions as the storage capacitor present in the image display area;
This is preferable because a liquid crystal display element can be manufactured at low cost.

A dummy terminal formed with the conductive film at both ends of the source electrode terminal block and the gate electrode terminal block, and an output electrode terminal of the film carrier on which an LSI for driving the switching element is mounted. It is preferable to connect to the ground terminal of the external printed circuit board via dummy wirings formed on both sides of the column in order to prevent a secondary discharge between the conductive film and the gate-source electrode terminal.

An electrode layer is formed on both ends of the source electrode terminal block and the gate electrode terminal block,
The electrode layer may be a lower electrode of a capacitor, the insulating film for forming the switching element may be a dielectric layer, and the conductive film may be electrically connected to an upper electrode of the capacitor. To prevent secondary discharge between the gate and the source electrode terminal.

It is preferable that the upper electrode of the capacitor is formed of a film under the same manufacturing conditions as the conductive film in order to manufacture a liquid crystal display element at low cost.

It is preferable that the lower electrode of the capacitor is formed of a film having the same manufacturing conditions as the source electrode terminal block and the gate electrode terminal block in order to manufacture a liquid crystal display element at low cost.

The capacitor used here is a capacitor used to store the electric charge discharged from the second transparent insulating substrate to the conductive layer. Further, a gate conductive film and a source conductive film refer to conductive films formed over a gate electrode terminal block and a source electrode terminal block, respectively.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is effective for, for example, measures against static electricity in an active matrix type liquid crystal display device.
This is because even in the case of a thin film transistor (TFT), the MIM (metal-insulator-
In the case of a metal) type diode, an insulating film is necessary when forming a switching element, and an electrode material is provided in a lower layer and an upper layer of the insulating layer. This is because a conductor layer for absorbing static electricity can be provided.

Next, the liquid crystal display device of the present invention will be described based on embodiments with reference to the drawings.

Embodiment 1 Hereinafter, a liquid crystal display device employing an inverted staggered transistor using amorphous silicon (hereinafter simply referred to as a-Si) as a semiconductor layer will be described with reference to FIGS. FIG. 1 is an explanatory plan view of a liquid crystal display device of the present invention. 2 is a sectional view showing a transistor portion of the liquid crystal display element of the present invention, FIG. 3 is a sectional view taken along line AA of FIG. 1, FIG. 4 is a sectional view taken along line BB of FIG. FIG. 5 is an explanatory diagram in which the liquid crystal display element of the present invention and an external circuit are connected.

In FIG. 1, reference numeral 1 denotes a glass substrate which is a transparent insulating substrate, 2 denotes a source wiring formed on the glass substrate 1, and 3a denotes a source electrode terminal provided at the tip of the source wiring 2. 3 is a source electrode terminal 3
Reference symbol a denotes a source electrode terminal block which is grouped by the number of electrode terminals included in a TCP (tape carrier package, a film carrier on which an LSI is mounted), 4 denotes a gate wiring, and 5a denotes the gate wiring. 5 is a gate electrode terminal provided at the tip of
Is a gate electrode terminal block grouped by the number of electrode terminals included in the TCP, 7 is a conductive film,
8 is a dummy terminal. In FIG. 2, 9 is a gate electrode, 10 is a gate insulating film, 11 is a display electrode, 12 is a channel layer, 13 is an etching stopper layer, 14 is a contact layer, and 15 is a drain electrode. And 16 is a source electrode. In FIG.
Is a second glass substrate (second transparent insulating substrate) facing the glass substrate 1.

Next, the manufacturing method of the liquid crystal display device of the present invention will be described.

First, as shown in FIG. 1, on a transparent insulating substrate made of, for example, glass, plastic, or the like, gate electrode terminals 5a are grouped by the number of electrode terminals included in the TCP. The gate wiring 4 formed integrally with the gate electrode terminal 5a, the source electrode terminal block 3 in which the source electrode terminals 3a are grouped by the number of electrode terminals included in the TCP, and the dummy terminal 8 are formed in the same process. For example, a film is formed by sputtering. As an electrode material, for example, Cr, Al,
Ta, Mo, Ti or the like is used.

Next, a gate insulating film 10 made of, for example, an SiN film or the like for covering between the gate electrode terminal block 5, the gate wiring 4 and the gate electrode terminal and between the source electrode terminals in FIG. FIG.
Is formed as shown in FIG. When the gate insulating film 10 is formed, a through hole is formed at a position x in FIG. 3 to make the source wiring 2 and the source electrode terminal 3 conductive.
Further, a display electrode 11 made of, for example, an ITO film or a tin oxide film is formed by, for example, sputtering. Further, the second glass substrate 6 and the gate insulating film 10
A liquid crystal material is sandwiched in a region 27 between the second glass substrate 6 and the glass substrate 1 on which the second glass substrate 6 is formed.
The liquid crystal material is sealed by sealing the space between the gate insulating film 10 and the gate insulating film 10.

Next, in order to form the transistor shown in FIG. 2, a gate electrode 9 formed simultaneously with the gate electrode terminal block 5 and the gate wiring 4 in FIG. 1 and a gate insulating film laminated on the gate electrode 9 are formed. On the surface of 10,
Further, a channel layer 12 made of an a-Si layer, an etching stopper layer 13, and a contact layer 14 made of an N ⁺ -type a-Si layer for obtaining an ohmic contact are successively formed by plasma CVD. Next, a drain electrode 15, a source electrode 16, a source line 2, and a conductive film 7 for absorbing static electricity, which are made of, for example, Al, Mo, or the like.
(See FIG. 1) are simultaneously formed by, for example, sputtering. Thereafter, though not shown, a passivation film such as a SiN film may be provided further above these films in order to prevent a DC component from entering the liquid crystal layer. In that case, at least a part of the passivation film on the conductive film 7 is removed to expose the surface of the conductive film 7. Further, a through hole (not shown) for conducting the dummy terminal 8 and the conductive film 7 is formed in the gate insulating film 10 at a position indicated by y in FIG.

Next, as shown in FIG. 5, the liquid crystal display element shown in FIG. 1 is connected to a drive circuit, for example, an external printed circuit board 23 via a film carrier 19. The film carrier 19 is, for example, an organic insulating film portion such as polyimide or polyester, and a conductive pattern portion formed by using a photolithography technique on a conductive metal foil such as a copper foil or a copper alloy foil. , A terminal row 21b on the output side on the gate side, a terminal row 22 on the input side, and an LSI 20 for driving a liquid crystal. Here, the source-side output terminal row 2 connected to the liquid crystal driving LSI 20
The terminal row 1a and the output-side terminal row 21b on the gate side are formed so as to match the pitch between the source electrode terminal block 3 and the gate electrode terminal block 5 of the liquid crystal display element 18, respectively. The input terminal rows 22 connected to the LSI are formed so as to match the output terminal pitch of the external printed circuit board. Film carrier 1
9 and the external printed circuit board 23 are connected with solder,
Alternatively, an anisotropic conductive film is used. A dummy pattern 24 corresponding to the dummy terminal 8 is formed on the film carrier so as to be directly connected to the ground terminal 29 of the external printed circuit board circuit 23 without being connected to the liquid crystal driving LSI 20.

In the terminal portion of the liquid crystal display element formed as described above, the second transparent insulating substrate, ie, the second
The electric charge charged on the surface of the glass substrate is discharged toward the conductive film 7 for electrostatic absorption which is the closest conductor. Accordingly, the gate electrode terminal block 5 and the source electrode terminal block 3 do not suffer from electrostatic damage caused by discharge. Further, the discharged electric charge is supplied to the ground terminal 2 of the external printed circuit board 23 via the dummy terminal 8 and the dummy pattern 24 of the film carrier.
Since it flows into 9, there is no secondary discharge.

In this embodiment, the drain and source electrode materials are used as the conductive film material for absorbing static electricity. However, as shown in FIG. 6, the material for forming the display electrode 11 is shown in FIG. The same effect as described above can be obtained by using the above method.

Embodiment 2 This embodiment is characterized in that a capacitor is formed outside the source electrode terminal and the gate electrode terminal. By forming the capacitor in this manner, the electric charge charged in the electrostatic absorption layer (conductive film) by the discharge from the end of the second transparent insulating substrate is stored in the capacitor.

FIG. 7 is a plan view showing the second embodiment, and FIG.
FIG. 8 is a sectional view taken along line CC of FIG. 7. In the same thing as FIG.
The same reference numerals are used, and the forming method is the same as that of the first embodiment except that the upper electrode 26 of the capacitor and the lower electrode 25 of the capacitor are formed. The lower electrode 25 of the capacitor is formed at the time of forming the gate wiring 4 similarly to the source electrode terminal block 3 and the gate electrode terminal block 5. The gate insulating film 10 is a dielectric of the capacitor, and is formed after forming the lower electrode 25 of the capacitor so as to be sandwiched between the lower electrode 25 of the capacitor and the upper electrode 26 of the capacitor. Next, the conductive film 7 for absorbing static electricity is stretched to form the upper electrode 26 of the capacitor. The upper electrode 26 of the capacitor may be a conductive film made of, for example, an ITO film or a tin oxide film used for forming a display electrode, or may be a conductive film made of, for example, Al or Mo used for forming a source electrode.

[0031]

According to the present invention, even if the surface of the liquid crystal display element is charged, the charge is discharged to the conductive film for absorbing static electricity, so that there is no static electricity trouble such as display failure.

Further, since the conductive film for electrostatic absorption is connected to an external ground terminal through dummy terminals provided at both ends of the electrode terminal group of the liquid crystal display element and a dummy pattern of the film carrier, discharged electric charges are generated. Flows to the ground terminal without being charged on the surface of the liquid crystal display element.

Further, by forming a capacitor by the conductive film for absorbing static electricity formed at the terminal of the liquid crystal display element and the electrodes formed at the outer regions at both ends of the electrode terminal, a second capacitor is formed.
Since the electric charge charged in the electrostatic absorption layer by the discharge from the end of the transparent insulating substrate is stored in the capacitor portion, the secondary discharge between the charge absorbing conductive film and the electrode terminal can be prevented. Therefore, display defects such as linear defects caused by static electricity entering only specific electrode terminals can be prevented, and a high-quality liquid crystal display device without defects can be manufactured at a high yield.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of a liquid crystal display device of the present invention.

FIG. 2 is a cross-sectional view illustrating an inverted staggered thin film transistor.

FIG. 3 is a cross-sectional view of the liquid crystal display device of FIG. 1 taken along line AA.

FIG. 4 is a sectional view of the liquid crystal display device of FIG. 1 taken along line BB.

FIG. 5 is a diagram in which an embodiment of the liquid crystal display device of the present invention and an external printed circuit board are connected.

FIG. 6 is a sectional view showing another embodiment of the liquid crystal display device of the present invention.

FIG. 7 is a plan view showing another embodiment of the liquid crystal display device of the present invention.

8 is a cross-sectional view of the liquid crystal display device of FIG. 7, taken along line CC.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Source wiring 3 Source electrode terminal block 3a Source electrode terminal 4 Gate wiring 5 Gate electrode terminal block 5a Gate electrode terminal 6 Second glass substrate 7 Conductive film 8 Dummy terminal 9 Gate electrode 10 Gate insulating film 11 Display electrode 18 Liquid crystal display device 19 Film carrier 21a Output-side terminal row on source side 21b Output-side terminal row on gate side 22 Terminal row on input side 25 Lower electrode of capacitor 26 Upper electrode of capacitor

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tohru Koshikawa 997 Miyoshi, Nishi-Koshi-cho, Kikuchi-gun, Kumamoto Inside Advanced Display Co., Ltd. (72) Inventor Hironori Aoki 997 Miyoshi, Nishi-Koshi-cho, Kikuchi-gun, Kumamoto In the display (56) References JP-A-7-175075 (JP, A) JP-A-3-85525 (JP, A) JP-A-5-303115 (JP, A) JP-A-4-130417 (JP, A) JP-A-6-258660 (JP, A) JP-A-6-11684 (JP, A) JP-A-3-170916 (JP, A) JP-A-7-225387 (JP, A) JP-A-63-1988 133124 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02F 1/1345 G02F 1/1362

Claims (8)

(57) [Claims] 1. A transparent insulating substrate, a second transparent insulating substrate having a size corresponding to an image display area, and sandwiched between the transparent insulating substrate and the second transparent insulating substrate. A plurality of gate electrode terminals, which are made of a liquid crystal material and are arranged in parallel and at equal intervals on the transparent insulating substrate, and are orthogonal to the gate electrode terminals, and are respectively arranged in parallel and at equal intervals. A plurality of source electrode terminals; a gate line and a source line formed respectively connected to the gate electrode terminal and the source electrode terminal; and a switching formed at an intersection of the gate line and the source line. Element and
A display electrode formed in each region divided by the gate wiring and the source wiring is formed, and the transparent insulating substrate and the second transparent insulating substrate are
What is claimed is: 1. A liquid crystal display device comprising: a liquid crystal display device which is arranged so as to have a similar shape, wherein said second transparent insulating substrate and said second transparent insulating substrate are overlapped from an end of said transparent insulating substrate. On the end region on the transparent insulating substrate up to the end of the insulating substrate, the gate electrode terminal for inputting a driving signal from the outside, the gate electrode terminal being connected to the gate wiring and the source wiring, respectively, and Source electrode terminal is LSI
The gate electrode terminal block and the source electrode terminal block each comprising one gate electrode terminal block and one source electrode terminal block by the number of electrode terminals included in one film carrier on which the film carrier is mounted. An insulating film is laminated on each upper layer of the block, and a source conductive film is further formed thereon, and perpendicularly to the source electrode terminal block, and over the source electrode terminal block, and formed on the gate electrode terminal block. A gate conductive film is formed vertically and over the gate electrode terminal block, and the source conductive film and the gate conductive film are
Each connected to child block and gate terminal block
End of the film carrier and the second transparent insulating substrate
In the area between the edges of the film carrier
A liquid crystal display element, which is exposed on the transparent insulating substrate even after the connection . 2. The liquid crystal display device according to claim 1, wherein said conductive film is a film formed under the same manufacturing conditions as a source electrode or a drain electrode for forming said switching element. 3. The liquid crystal display device according to claim 1, wherein the conductive film is a film formed under the same manufacturing conditions as the display electrode. 4. The liquid crystal display device according to claim 1, wherein the conductive film is formed of a film under the same manufacturing conditions as an auxiliary capacitor existing in an image display area. 5. The film carrier according to claim 1, wherein the conductive film is provided with dummy terminals formed at both ends of the source electrode terminal block and the gate electrode terminal block, and an LSI for driving the switching element. 2. The liquid crystal display element according to claim 1, wherein the liquid crystal display element is connected to a ground terminal of an external printed circuit board via dummy wirings formed on both sides of the output electrode terminal row. 6. An electrode layer is formed at both ends of each of the source electrode terminal block and the gate electrode terminal block, the electrode layer is used as a lower electrode of a capacitor, and an insulating film for forming the switching element is a dielectric layer. 2. The liquid crystal display device according to claim 1, wherein the conductive film is electrically connected to an upper electrode of the capacitor. 7. The liquid crystal display device according to claim 6, wherein the upper electrode of the capacitor is a film formed under the same manufacturing conditions as the conductive film. 8. The liquid crystal display device according to claim 6, wherein the lower electrode of the capacitor is formed of a film having the same manufacturing conditions as the source electrode terminal block and the gate electrode terminal block.