JP2013148784A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device that can protect plural wires connected to a terminal block.SOLUTION: A TFT substrate 2 includes, on a liquid crystal layer 4 side, plural wires 25 extending from a superimposed section A to a non-superimposed section B, a protective film 27 covering the plural wires 25, a terminal block 29a provided in the non-superimposed section B and connected to the plural wires 25, and a protective member 6 placed on the protective film 27 between a seal member 5 and the terminal block 29a.

Description

  The present invention relates to a liquid crystal display device, and more particularly to protection of wiring.

  In a liquid crystal display device, a liquid crystal layer is held between two substrates. One of the two substrates has a non-overlapping portion that does not overlap with the other substrate, and the non-overlapping portion is provided with a terminal group connected to a plurality of wirings extending from the pixel group. The plurality of wirings are covered with a protective film for preventing corrosion.

JP 2007-78931 A

  By the way, a substrate having a plurality of wirings as described above may be subjected to a mechanical shock during panel assembly or panel cutting, and the protective film on the surface layer is scraped off so that a part of the wiring is removed. May be exposed to the open air. If a part of the wiring is exposed to the outside air, corrosion may proceed from there and the conductivity may be deteriorated. In particular, in the vicinity of the terminal group, such a problem is likely to occur because chips fly when the counterpart substrate is cut.

  The present invention has been made in view of the above circumstances, and a main object thereof is to provide a liquid crystal display device capable of protecting a plurality of wirings connected to a terminal group.

  In order to solve the above problems, a liquid crystal display device according to the present invention includes a first substrate, a second substrate, a liquid crystal layer held between the first substrate and the second substrate, A seal member sandwiched between the first substrate and the second substrate and surrounding the liquid crystal layer. The first substrate includes an overlapping portion that overlaps with the second substrate and a non-overlapping portion that does not overlap with the second substrate. The first substrate is provided on the liquid crystal layer side, provided on the non-overlapping part, a plurality of wirings extending from the overlapping part to the non-overlapping part, a protective film covering the plurality of wirings, and the plurality of wirings And a protective member disposed on the protective film between the seal member and the terminal group.

  According to the present invention, it is possible to protect a plurality of wirings connected to the terminal group by disposing the protective member between the seal member and the terminal group.

  1 aspect of this invention WHEREIN: The said protection member contains the metal layer arrange | positioned on the said protective film, and the protective layer which covers the said metal layer. According to this, it is possible to improve the effectiveness of protection by including a plurality of layers. Moreover, corrosion of the metal layer can be suppressed by covering the metal layer with the protective layer.

  The first substrate further includes a thin film transistor connected to the plurality of wirings and covered with the protective film, and a common signal line disposed on the protective film, and is included in the protective member. The metal layer may be formed of the same material as the common signal line. According to this, in the case of a structure in which the common signal line is provided above the thin film transistor, the metal layer of the protective member can be formed by using the process of forming the common signal line.

  The common signal line may be connected to a part of the plurality of wirings through a via conductor formed in the protective film. According to this, even when the metal layer of the protective member is formed in the same layer as the common signal line, the common signal line is connected to the terminal group using the wiring provided below the common signal line. It is possible.

  1 aspect of this invention WHEREIN: The said protection member is arrange | positioned ranging over the said superimposition part and the said non-overlapping part. According to this, it is possible to effectively suppress damage to the protective film due to chips flying when cutting the second substrate.

It is sectional drawing which represents typically the principal part of the liquid crystal display device which concerns on one Embodiment of this invention. It is a top view which represents typically the principal part of the TFT substrate of the said liquid crystal display device. It is process drawing showing the example of a manufacturing process of the TFT substrate of the said liquid crystal display device. It is process drawing following FIG. 3A. It is process drawing following FIG. 3B. It is process drawing following FIG. 3C. It is process drawing following FIG. 3D. It is process drawing following FIG. 3E. It is process drawing following FIG. 3F. It is process drawing following FIG. 3G. It is sectional drawing which represents typically the principal part of the TFT substrate of the said liquid crystal display device. It is a figure showing the subject of a comparative example. It is a figure showing the effect of an Example.

  An embodiment of a liquid crystal display device of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing a main part of the liquid crystal display device 1. FIG. 2 is a top view schematically showing the main part of the TFT substrate 2 of the liquid crystal display device 1. Note that the wiring 25 and the terminals 29 shown in FIG. 2 are made wider and fewer than the actual ones for easy viewing.

  The liquid crystal display device 1 includes a TFT substrate 2 as a first substrate, a CF substrate 3 as a second substrate, a liquid crystal layer 4 held between the TFT substrate 2 and the CF substrate 3, and a TFT substrate 2. And a CF member 3 and a sealing member 5 surrounding the liquid crystal layer 4. The TFT substrate 2 includes a thin film transistor (TFT) described later as a switching element. The CF substrate 3 includes a glass substrate 31 and a color filter (CF) 33 disposed on the glass substrate 31.

  The TFT substrate 2 is configured in a rectangular shape that is slightly larger than the CF substrate 3, and includes an overlapping portion A that overlaps the CF substrate 3 and a non-overlapping portion B that does not overlap the CF substrate 3. Specifically, the portion of the TFT substrate 2 that is located on the inner side in the in-plane direction from the edge 39 of the CF substrate 3 and faces the CF substrate 3 is the overlapping portion A, and the surface of the TFT substrate 2 is more than the edge 39 of the CF substrate 3. A portion that is located outside inward and does not face the CF substrate 3 is a non-overlapping portion B.

  A plurality of pixels including TFTs are arranged in a grid pattern on the overlapping portion A of the TFT substrate 2, and a plurality of wirings 25 connected to each TFT extend from the overlapping portion A to the non-overlapping portion B. The plurality of wirings 25 are, for example, source signal lines connected to the source electrode of the TFT (or drain signal lines connected to the drain electrode). The plurality of wirings 25 are covered with a protective film 27 for preventing corrosion.

  In the non-overlapping portion B of the TFT substrate 2, a terminal group 29 a including a plurality of terminals 29 connected to the end portions of the respective wirings 25 is provided. In the terminal group 29a, ends of a plurality of wirings 25 are collected, and a plurality of terminals 29 connected thereto are arranged one-dimensionally along the edge 22 of the TFT substrate 2 (see FIG. 2). ). A flexible printed circuit board on which a driver IC is mounted may be connected to the terminal group 29a, or the driver IC may be directly mounted.

  In the TFT substrate 2, the protective member 6 for protecting the protective film 27 and the plurality of wirings 25 from mechanical impact is disposed on the protective film 27 between the seal member 5 and the terminal group 29 a. . The protection member 6 extends in a strip shape along the edge 22 of the TFT substrate 2 and the terminal group 29a (see FIG. 2). An end portion of the protective member 6 that protrudes in the extending direction from the terminal group 29 a extends toward the edge 22 of the TFT substrate 2. Further, the protective member 6 is disposed across the overlapping portion A and the non-overlapping portion B of the TFT substrate 2. That is, the protection member 6 is disposed so as to overlap with the edge 39 of the CF substrate 3 in a top view. The protective member 6 has a multilayer structure including a metal layer 61 disposed on the protective film 27 and a protective layer 63 covering the metal layer 61.

  The metal layer 61 included in the protective member 6 is made of a metal such as Cu or Al, and preferably has a thickness of about 200 to 400 nm. The protective layer 63 included in the protective member 6 is made of a transparent insulating material such as SiN, and preferably has a thickness of about 300 to 600 nm. The protective member 6 preferably has a total thickness of about 600 to 900 nm, for example. Further, the protective film 27 located below the protective member 6 is made of a transparent insulating material such as SiN, and preferably has a thickness of about 300 to 600 nm. The wiring 25 located below the protective film 27 is preferably made of a metal such as Cu or Al, and preferably has a thickness of about 200 to 400 nm.

  3A to 3H are process diagrams illustrating an example of a manufacturing process of the TFT substrate 2 of the liquid crystal display device 1. The left half of each figure shows a TFT formation region, and the right half shows a protective member 6 formation region. Each drawing shows a state in which the photoresist is removed after the photolithography process and the thin film processing by etching are completed. Here, the photolithography process is a process including a series of processes for forming a resist pattern from application of a photoresist, through selective exposure using a photomask, and development. Then, detailed description is abbreviate | omitted.

  In the step shown in FIG. 3A, a gate electrode 71 made of a metal such as Cu or Al is formed on the glass substrate 21 in the TFT formation region. Specifically, first, a metal film made of a metal such as Cu or Al is formed by sputtering. Next, a resist pattern is formed on the metal film by a photolithography process, then the metal film is etched, and then the photoresist is peeled off. Thereby, the gate electrode 71 is formed.

  3B, an insulating film 23 made of a transparent insulating material such as SiN covering the glass substrate 21 and the gate electrode 71 is formed, and amorphous Si (on the gate electrode 71 and the insulating film 23 is formed. A semiconductor layer 73 made of a semiconductor such as a-Si) is formed. Specifically, first, an insulating film made of SiN is formed by introducing ammonia gas, silane gas, and nitrogen gas into the reaction chamber of the CVD apparatus. Next, a semiconductor film made of amorphous Si is formed by introducing silane gas and hydrogen gas. Next, a resist pattern is formed on the semiconductor film by a photolithography process, then the semiconductor film is etched, and then the photoresist is peeled off. Thereby, the insulating film 23 and the semiconductor layer 73 are formed.

  In the step shown in FIG. 3C, the source electrode 74 and the drain electrode 75 made of a metal such as Cu or Al are formed on the semiconductor layer 73, and the TFT is completed. In the same process, a plurality of wirings 25 made of a metal such as Cu or Al are also formed on the insulating film 23. The plurality of wirings 25 are source signal lines connected to the source electrode 74 and extend to the formation region of the terminal group 29a through the formation region of the protection member 6 (see FIG. 1). Specifically, first, a metal film made of a metal such as Cu or Al is formed by sputtering. Next, a resist pattern is formed on the metal film by a photolithography process, then the metal film is etched, and then the photoresist is peeled off. Thereby, the source electrode 74, the drain electrode 75, and the some wiring 25 are formed.

  3D, the protective film 27 made of a transparent insulating material such as SiN covering the source electrode 74, the drain electrode 75, and the plurality of wirings 25 is formed. Further, the protective film 27 is formed with a hole 27a where the drain electrode 75 is exposed to the bottom. Specifically, first, a protective film made of SiN is formed by introducing ammonia gas, silane gas, and nitrogen gas into the reaction chamber of the CVD apparatus. Next, a resist pattern is formed on the protective film by a photolithography process, then the protective film is etched, and then the photoresist is peeled off. Thereby, the protective film 27 having the holes 27a is formed.

  In the step shown in FIG. 3E, the common electrode 76 made of a transparent conductive material such as tin-added indium oxide (ITO) is formed on the protective film 27. Specifically, first, a transparent conductive film made of ITO is formed on the protective film 27 by sputtering. Next, a resist pattern is formed on the transparent conductive film by a photolithography process, then the transparent conductive film is etched, and then the photoresist is peeled off. Thereby, the common electrode 76 is formed.

  In the step shown in FIG. 3F, a common signal line (common signal line) 77 made of a metal such as Cu or Al connected to the common electrode 76 is formed. In the same process, a metal layer 61 made of a metal such as Cu or Al is also formed on the protective film 27 in the region where the protective member 6 is formed. Specifically, first, a metal film made of a metal such as Cu or Al is formed by sputtering. Next, a resist pattern is formed on the metal film by a photolithography process, then the metal film is etched, and then the photoresist is peeled off. Thereby, the common signal line 77 and the metal layer 61 are formed.

  3G, the protective film 28 made of a transparent insulating material such as SiN covering the common electrode 76, the common signal line 77, and the metal layer 61 is formed. Similarly to the protective film 27, the protective film 28 is formed with a hole 27a in which the drain electrode 75 is exposed at the bottom. Further, a portion of the protective film 28 formed on the metal layer 61 becomes a protective layer 63 included in the protective member 6. Specifically, first, a protective film made of SiN is formed by introducing ammonia gas, silane gas, and nitrogen gas into the reaction chamber of the CVD apparatus. Next, a resist pattern is formed on the protective film by a photolithography process, then the protective film is etched, and then the photoresist is peeled off. Thereby, the protective film 28 having the holes 27a is formed, and the protective member 6 including the metal layer 61 and the protective layer 63 is completed. In this step, a hole for forming the terminal 29 (see FIG. 1) is also formed in the non-overlapping portion B.

  In the step shown in FIG. 3H, a pixel electrode 78 made of a transparent conductive material such as tin-added indium oxide (ITO) is formed on the protective film 28 and in the hole 27a. The pixel electrode 78 is connected to the drain electrode 75 through the hole 27a. Specifically, first, a transparent conductive film made of ITO is formed on the protective film 28 by sputtering. Next, a resist pattern is formed on the transparent conductive film by a photolithography process, then the transparent conductive film is etched, and then the photoresist is peeled off. Thereby, a pixel electrode 78 connected to the drain electrode 75 is formed. In this step, a terminal 29 (see FIG. 1) made of a transparent conductive material such as ITO is also formed in the non-overlapping portion B.

  The TFT substrate 2 is completed through the above steps. Then, the liquid crystal display panel is completed by injecting the liquid crystal layer 4 between the TFT substrate 2, the CF substrate 3, and the seal member 5, and the liquid crystal display device 1 is completed by assembling a driver IC or the like to the liquid crystal display panel. .

  In the above embodiment, since the metal layer 61 included in the protective member 6 is formed in the same layer as the common signal line 77, when the common signal line 77 is extended to the terminal group 29a on the protective film 27, The metal layer 61 gets in the way. Therefore, as shown in FIG. 4, the common signal line 77 is not connected to the TFT 25 (for example, the plurality of wires 25 among the plurality of wires 25) through the via conductor 79 formed in the protective film 27. By connecting to the wiring 25), it is possible to connect the common signal line 77 to the terminal group 29a.

  FIG. 5A is a diagram illustrating a problem of the comparative example. The comparative example is a conventional liquid crystal display device that does not have the above-described protective member. The thickness of the protective film on the surface layer of the TFT substrate is about 450 nm, the thickness of the wiring below it is about 300 nm, and the insulating film below it is The thickness is about 350 nm. In the production of a large number of liquid crystal display devices, those having scratches on the surface of the TFT substrate were selected, and the reach depth of each scratch was evaluated. The reach depth of the scratch was measured by cross-sectional SEM observation. In FIG. 5A, the horizontal axis of the graph represents the depth of arrival of scratches from the surface, and the vertical axis of the graph represents the total scratch occupation rate. According to this, it is found that there are 47% of scratches occurring only on the surface protective film, 51% of the scratches reaching the underlying wiring, and 2% of the scratches reaching the insulating film below. That is, more than half of the scratches may cause corrosion of the wiring.

  FIG. 5B is a diagram illustrating the effect of the embodiment. An example is the liquid crystal display device of the present embodiment having the above-described protective member, wherein the protective layer included in the protective member has a thickness of about 450 nm, the metal layer included in the protective member has a thickness of about 300 nm, and thereunder The thickness of the protective layer is about 550 nm, the thickness of the underlying wiring is about 300 nm, and the thickness of the insulating film therebelow is about 350 nm. FIG. 5B is a graph in which the relationship between the reach depth of the scratches and the total occupation rate in the comparative example of FIG. 5A is applied to the example. According to this, it can be seen that all the scratches do not reach the wiring. Therefore, in the embodiment, it is possible to protect the wiring from damage and corrosion.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made by those skilled in the art.

  In the above embodiment, the protective member 6 has a two-layer structure, but is not limited thereto, and may be one layer or three or more layers. For example, when forming the transparent conductive film in the step shown in FIG. 3H, the protective member 6 may be formed in a three-layer structure by forming the transparent conductive film in the region where the protective member 6 is formed. When scratches occur, it tends to be scraped off in units of layers, so it is advantageous to have a larger number of layers. In addition, for example, a protective member made of a resin material or the like may be separately manufactured and attached onto the protective film 27 of the TFT substrate 2.

  In the above embodiment, the pixel structure in which the common signal line 77 is provided above the TFT is shown. However, the present invention is not limited to this, and the pixel structure has the common signal line 77 provided in the same layer as the gate electrode 71. Also good.

  In the above embodiment, the IPS (In Plane Switching) method in which the TFT substrate 2 is provided with the common electrode 76 and the pixel electrode 78 has been described. However, the present invention can also be applied to a TN or VA liquid crystal display device.

  In the above embodiment, the active matrix system in which each pixel of the TFT substrate 2 is provided with a TFT has been described. However, the present invention can also be applied to a simple matrix liquid crystal display device.

  DESCRIPTION OF SYMBOLS 1 Liquid crystal display device, 2 TFT substrate (an example of the 1st substrate), 21 Glass substrate, 22 Edge, 23 Insulating film, 25 Wiring, 27 Protective film, 27a Hole, 28 Protective film, 29 terminal, 29a terminal group, 3 CF substrate (example of second substrate), 31 glass substrate, 33 color filter, 39 edge, 4 liquid crystal layer, 5 sealing member, 6 protective member, 61 metal layer, 63 protective layer, 71 gate electrode, 73 semiconductor layer, 74 source electrode, 75 drain electrode, 76 common electrode, 77 common signal line, 78 pixel electrode, 79 via conductor, A overlapping portion, B non-overlapping portion.

Claims (5)

Sandwiched between a first substrate, a second substrate, a liquid crystal layer held between the first substrate and the second substrate, the first substrate and the second substrate, A liquid crystal display device comprising a seal member surrounding the liquid crystal layer,
The first substrate includes an overlapping portion that overlaps the second substrate, and a non-overlapping portion that does not overlap the second substrate,
The first substrate is on the liquid crystal layer side,
A plurality of wires extending from the overlapping portion to the non-overlapping portion;
A protective film covering the plurality of wirings;
A terminal group provided in the non-overlapping portion and connected to the plurality of wirings;
A protective member disposed on the protective film between the seal member and the terminal group;
Having
A liquid crystal display device characterized by the above. The protective member includes a metal layer disposed on the protective film, and a protective layer covering the metal layer.
The liquid crystal display device according to claim 1. The first substrate further includes a thin film transistor connected to the plurality of wirings and covered with the protective film, and a common signal line disposed on the protective film,
The metal layer included in the protective member is formed of the same material as the common signal line.
The liquid crystal display device according to claim 2. The common signal line is connected to a part of the plurality of wirings through a via conductor formed in the protective film.
The liquid crystal display device according to claim 3. The protective member is disposed across the overlapping portion and the non-overlapping portion,
The liquid crystal display device according to claim 1.

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