WO2012132346A1

WO2012132346A1 - Display device

Info

Publication number: WO2012132346A1
Application number: PCT/JP2012/001982
Authority: WO
Inventors: 安松　拓人
Original assignee: シャープ株式会社
Priority date: 2011-03-29
Filing date: 2012-03-22
Publication date: 2012-10-04

Abstract

A liquid crystal display device (1) is provided with a TFT substrate (2) comprising a flexible plastic substrate (6) and a display element layer (7) formed on the plastic substrate (6), and the liquid crystal display device (1) has a terminal region (T) in which a terminal (9) having a flexible printed substrate (24) connected thereto is formed. The terminal (9) and a terminal (25) formed in the flexible printed substrate (24) are electrically connected by way of a conductive adhesive layer (16) containing conductive particles. A moisture-proof material (30) which covers the TFT substrate (2) and flexible printed substrate (24) so as to seal the terminal (9) is provided in the terminal region (T).

Description

Display device

The present invention relates to a display device such as a liquid crystal display device provided with a plastic substrate.

In recent years, in the display field, display devices using plastic substrates, which have great advantages over glass substrates in terms of flexibility, impact resistance and light weight, have received much attention. This has the potential to create a new display device.

As such a display device, for example, a pair of substrates (that is, a TFT (Thin Film Transistor) substrate and a CF (Color Filter) substrate) disposed opposite to each other and a liquid crystal provided between the pair of substrates. A liquid crystal display device having a layer has been proposed.

In this liquid crystal display device, the TFT substrate includes a flexible plastic substrate formed of polyimide resin or the like, and a display element layer provided on the plastic substrate and having a TFT as a switching element. The CF substrate includes the above-described plastic substrate and a CF element layer provided on the plastic substrate.

Further, in this liquid crystal display device, a flexible printed circuit board is used as a drive circuit substrate in order to cope with the reduction in thickness and size of the liquid crystal display device. And the terminal formed in the flexible printed circuit board is connected to the terminal formed in the TFT substrate of the liquid crystal display device through the conductive adhesive layer.

Here, when a plastic substrate is used, since the plastic substrate easily allows moisture (water vapor) in the air to pass therethrough, the moisture cannot be sufficiently blocked. Therefore, moisture that has permeated the plastic substrate enters the display device, resulting in a problem that the reliability of the display device is lowered.

Therefore, a display device including a moisture-proof film for preventing moisture from entering the display device has been proposed. More specifically, a display device is disclosed in which a pair of moisture-proof films are laminated on the outer periphery of a display element (display region) constituting the display device so as to sandwich the display element. And since such a structure will be in the state where the whole display element was covered with a pair of moisture-proof films, it is described that intrusion of moisture from the outside can be blocked in the display area (for example, patents) Reference 1).

JP 2007-178706 A

However, the display device described in Patent Document 1 simply has a pair of moisture-proof films provided on the outer periphery of the display element so as to sandwich the display element.

That is, generally, as a conductive adhesive layer for connecting terminals, for example, an insulating thermosetting resin such as the above-described epoxy resin is a main component, and fine particles (for example, spherical shape) are contained in the resin. A conductive adhesive layer in which conductive particles made of metal fine particles or metal fine particles made of spherical resin particles plated with metal are dispersed is used.

When the terminal formed on the flexible printed circuit board and the terminal formed on the TFT substrate are connected via the conductive adhesive layer, the conductive adhesive layer is heated to a predetermined curing temperature. Thus, the conductive adhesive layer is pressurized via the flexible printed circuit board, and the conductive adhesive layer is heated and melted to electrically connect the terminals.

However, since a plastic substrate having flexibility is used, when performing the above pressure treatment, fine particles contained in the conductive adhesive layer bite into the terminals formed on the TFT substrate, The terminal will crack. If a crack occurs in the terminal, the terminal is oxidized and insulated by moisture entering from the outside. As a result, a connection failure occurs and the connection reliability of the flexible printed circuit board decreases. It was.

Therefore, the present invention has been made in view of the above-described problem, and can effectively suppress the intrusion of moisture in the terminal region and can prevent a decrease in connection reliability of the drive circuit board. An object is to provide an apparatus.

In order to achieve the above object, a display device of the present invention comprises a display device substrate having a flexible plastic substrate and a display element layer formed on the plastic substrate, and a display region for displaying an image. And a terminal region provided in the periphery of the display region and provided with a terminal to which a drive circuit substrate is connected, and is driven with the display device substrate via a conductive adhesive layer containing conductive particles. A display device in which a circuit board is bonded and a terminal and another terminal formed on the driving circuit board are electrically connected, and the display device substrate and the driving circuit board are sealed so as to seal the terminal in the terminal region. A moisture-proof material for covering is provided.

According to this configuration, heat and pressure treatment is performed to connect the flexible printed circuit board to the terminal area of the display device substrate including the plastic substrate, and the terminal and other terminals are electrically connected through the conductive adhesive layer. Even when the conductive particles contained in the conductive adhesive layer bite into the terminal when the terminal is cracked, the terminal is sealed with a moisture-proof material. Can be reliably prevented. Therefore, the terminal can be prevented from being oxidized and insulated due to water vapor, and as a result, connection failure can be prevented and connection reliability of the flexible printed circuit board can be prevented from being lowered.

Also, by providing a moisture-proof material in the terminal region, it becomes possible to effectively prevent the occurrence of deformation such as warpage and undulation in the plastic substrate due to the invasion of water vapor. As a result, it is possible to prevent a decrease in connection reliability of the flexible printed circuit board.

In the display device of the present invention, the conductive adhesive layer may be composed of an anisotropic conductive adhesive layer.

According to this configuration, even when an anisotropic conductive adhesive containing conductive particles made of fine particles is used as the conductive adhesive layer, the terminal is sealed by the moisture-proof material, so that the external Invasion of water vapor from can be reliably prevented.

In the display device of the present invention, the moisture-proof material may be constituted by a laminated film in which an adhesive layer and a water vapor barrier layer are laminated.

According to the same configuration, since the moisture-proof material is a laminated film in which the adhesive layer and the water vapor barrier layer are laminated, the moisture-proof material can be formed with a simple configuration. Further, since the adhesive layer is provided, a moisture-proof material can be easily provided in the terminal region.

In the display device of the present invention, the water vapor barrier layer may be formed of a metal film or an inorganic film.

According to this configuration, the water vapor barrier layer can be formed with a simple configuration.

In the display device of the present invention, the metal film may be made of SUS or aluminum.

According to this configuration, the metal film can be formed from a cheap and versatile metal material.

In the display device of the present invention, the inorganic film may be composed of at least one selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, and aluminum oxide.

According to this configuration, the inorganic film can be formed from an inexpensive and versatile inorganic material.

In the display device of the present invention, the water vapor barrier layer may have a thickness of 10 nm to 20 μm.

According to this configuration, it is possible to sufficiently exhibit the water vapor barrier performance without causing the disadvantage that the water vapor barrier layer is difficult to bend and adhesion is difficult.

In the display device of the present invention, a base film may be provided between the adhesive layer and the water vapor barrier layer.

According to this configuration, it is possible to protect the water vapor barrier layer that is easily damaged in a thin film state and difficult to handle, and to make the water vapor barrier layer easy to handle.

In the display device of the present invention, the plastic substrate may be formed of one selected from the group consisting of polyimide resin, polyparaxylene resin, and acrylic resin.

In addition, the display device of the present invention has an excellent characteristic that it is possible to prevent the occurrence of connection failure and prevent the connection reliability of the flexible printed circuit board from being lowered. Accordingly, the present invention further includes another display device substrate disposed opposite to the display device substrate, and a display medium layer provided between the display device substrate and the other display device substrate. It is preferably used for an apparatus. Moreover, this invention is used suitably when a display medium layer is a liquid crystal layer.

According to the present invention, in a display device including a flexible plastic substrate, it is possible to prevent a decrease in connection reliability of the drive circuit substrate.

It is a top view which shows the liquid crystal display device which concerns on embodiment of this invention. 1 is a perspective view showing a liquid crystal display device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing the liquid crystal display device according to the embodiment of the present invention, and is a cross-sectional view taken along the line AA of FIG. It is sectional drawing which shows the moisture proof material in the liquid crystal display device which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the liquid crystal display device which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the liquid crystal display device which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the liquid crystal display device which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the liquid crystal display device which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the liquid crystal display device which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the liquid crystal display device which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the liquid crystal display device which concerns on embodiment of this invention. It is sectional drawing which shows the modification of the liquid crystal display device which concerns on embodiment of this invention. It is sectional drawing which shows the modification of the moisture proof material in the liquid crystal display device which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, a liquid crystal display device is exemplified as the display device.

FIG. 1 is a plan view showing a liquid crystal display device according to an embodiment of the present invention, and FIG. 2 is a perspective view showing the liquid crystal display device according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing the liquid crystal display device according to the embodiment of the present invention, and is a cross-sectional view taken along the line AA in FIG.

As shown in FIGS. 1 to 3, the liquid crystal display device 1 includes a TFT substrate 2 that is a display device substrate on which a plurality of thin film transistors (TFTs) that are switching elements are formed, and a TFT substrate 2 facing the TFT substrate 2. A CF substrate 3 that is another display device substrate disposed, and a liquid crystal layer 4 that is a display medium layer provided between the TFT substrate 2 and the CF substrate 3 are provided. The liquid crystal display device 1 is sandwiched between the TFT substrate 2 and the CF substrate 3, and a seal provided in a frame shape for adhering the TFT substrate 2 and the CF substrate 3 to each other and enclosing the liquid crystal layer 4. Material 5 is provided.

The sealing material 5 is formed so as to circulate around the liquid crystal layer 4, and the TFT substrate 2 and the CF substrate 3 are bonded to each other via the sealing material 5. The TFT substrate 2 and the CF substrate 3 are each formed in a rectangular plate shape. In addition, the liquid crystal display device 1 includes a plurality of photo spacers (not shown) for regulating the thickness of the liquid crystal layer 4 (that is, the cell gap).

In the liquid crystal display device 1, as shown in FIGS. 1 and 3, a display area D for displaying an image is defined in an area inside the sealing material 5 where the TFT substrate 2 and the CF substrate 3 overlap. Here, the display area D is configured by arranging a plurality of pixels, which are the minimum unit of an image, in a matrix.

As shown in FIGS. 1 and 3, the liquid crystal display device 1 is formed in a rectangular shape, and in the longitudinal direction Y of the liquid crystal display device 1, the TFT substrate 2 protrudes from the CF substrate 3 on the upper side thereof. A terminal region T is defined in the protruding region. The terminal area T is provided around the display area D as shown in FIG.

Further, as shown in FIG. 1, the terminal region T is provided with a plurality of terminals 9 and connection wirings 20 connected to each of the plurality of terminals 9.

As shown in FIGS. 1 and 3, one end of the terminal region T is connected to the terminal 9, and a flexible printed circuit board 24, which is a drive circuit board for supplying signals from the outside, is attached. .

As shown in FIG. 3, in the liquid crystal display device 1 of the present embodiment, the TFT substrate 2 and the flexible printed circuit board 24 are bonded to each other in the terminal region T via the conductive adhesive layer 16 having adhesiveness. In addition, the terminals 9 and the terminals 25 formed on the flexible printed circuit board 24 are electrically connected.

The conductive adhesive layer 16 is not particularly limited as long as it has conductivity and has an adhesive force capable of bonding and fixing the TFT substrate 2 and the flexible printed board 24. For example, a film adhesive or the like can be used as the conductive adhesive layer 16.

As the film-like adhesive, an adhesive containing conductive particles can be used, for example, an insulating thermosetting resin as a main component and conductive particles dispersed in the resin can be used.

As the thermosetting resin, for example, an epoxy resin, a polyimide resin, a polyurethane resin, or the like can be used. In addition, it is preferable to use an epoxy resin as a thermosetting resin from a viewpoint of improving the adhesiveness of a film-form adhesive, and film formability.

Also, as the conductive particles, for example, metal particles such as copper, silver, gold and nickel can be used. In addition, the film adhesive should just have at least 1 sort (s) as a main component among the above-mentioned thermosetting resins, and should just use at least 1 sort (s) among the above-mentioned metal particles.

Also, an anisotropic conductive adhesive containing conductive particles can be used as the film adhesive. More specifically, as the anisotropic conductive adhesive, for example, an insulating thermosetting resin such as the above-mentioned epoxy resin is a main component, and fine particles (for example, spherical metal particles) are contained in the resin. Or conductive particles made of metal particles made of spherical resin particles plated with metal) can be used.

Then, by using an anisotropic conductive adhesive as the conductive adhesive layer 16, the thickness direction of the anisotropic conductive adhesive (that is, the conductive adhesive layer 16) (direction of arrow X in FIG. 3). , The terminal 9 and the flexible printed circuit board 24 are fixed so as to face each other, and the terminal 9 and the flexible printed circuit board 24 are electrically connected to each other, and the conductive adhesive having insulation in other directions is used. Layer 16 can be realized. In addition, as this anisotropic conductive adhesive, for example, a film-like anisotropic conductive film (Anisotropic Conductive Film) can be used.

The TFT substrate 2 includes a plastic substrate 6 having a film-like flexibility formed from a resin material. As a resin material for forming the plastic substrate 6, for example, an organic material such as polyimide resin, polyparaxylene resin, or acrylic resin can be used.

Further, on the plastic substrate 6 of the TFT substrate 2, a display element layer 7 provided with TFTs and the like is formed.

Here, the display element layer 7 includes a plurality of gate lines (not shown) extending in parallel with each other on the plastic substrate 6, and a plurality of source lines (not shown) extending in parallel with each other so as to be orthogonal to the gate lines. A plurality of TFTs (not shown) provided at respective intersections of gate lines and source lines, and a plurality of pixel electrodes (not shown) respectively connected to the respective TFTs are provided.

Further, the CF substrate 3 includes a plastic substrate 8 having a film-like flexibility (flexibility) formed of a resin material, like the TFT substrate 2. As the resin material for forming the plastic substrate 8, the same material as the organic material for forming the plastic substrate 6 described above can be used.

Further, a CF element layer 19 is formed on the plastic substrate 8 of the CF substrate 3. Here, the CF element layer 19 is provided between each colored layer and a plurality of colored layers (not shown) colored red, green, or blue, corresponding to each pixel electrode on the TFT substrate 2. And a color filter composed of a black matrix (not shown). The CF element layer 19 includes an overcoat layer (not shown) provided on the color filter, a common electrode (not shown) provided on the overcoat layer, and an alignment film (not shown) provided on the common electrode. (Not shown).

The thickness of the

plastic substrates

6 and 8 is preferably 3 to 30 μm. If the thickness is less than 3 μm, sufficient mechanical strength may not be obtained. If the thickness is greater than 30 μm, a plastic substrate may be used when forming the display element layer 7 or the CF element layer 19. This is because the warpages of 6 and 8 become large and a problem may occur in the process.

The liquid crystal layer 4 includes, for example, nematic liquid crystal having electro-optical characteristics.

A polarizing plate (not shown) is provided outside the TFT substrate 2, and a backlight unit (not shown) is provided outside the polarizing plate. A polarizing plate (not shown) is provided outside the CF substrate 3.

Here, in the liquid crystal display device 1 of the present embodiment, as shown in FIGS. 1 to 3, the TFT substrate 2 and the flexible printed circuit board so as to seal the terminal 9 in the terminal region T of the liquid crystal display device 1. This is characterized in that a moisture-proof material 30 covering 24 is provided.

More specifically, a moisture-proof material 30 is provided on the outer surface of the TFT substrate 2 and the outer surface of the flexible printed board 24 in the terminal region T, and the terminals 9 are sealed by the moisture-proof material 30.

With such a configuration, heat and pressure treatment is performed to connect the flexible printed circuit board 24 to the terminal region T of the TFT substrate 2 including the plastic substrate 6, and the

terminals

9 and 25 are interposed via the conductive adhesive layer 16. Even when the conductive particles contained in the conductive adhesive layer 16 bite into the terminals 9 and cracks occur in the terminals 9, the terminals 9 are sealed by the moisture-proof material 30. Therefore, it is possible to reliably prevent water vapor from entering from the outside. Therefore, the terminal 9 can be prevented from being oxidized and insulated due to water vapor, and as a result, connection failure can be prevented and connection reliability of the flexible printed circuit board 24 can be prevented from being lowered.

In particular, when the above-mentioned anisotropic conductive adhesive layer is used as the conductive adhesive layer, since the conductive particles made of fine particles are used, the terminal 9 is likely to be cracked. Even when an anisotropic conductive adhesive layer is used, since the terminal 9 is sealed by the moisture-proof material 30, it is possible to reliably prevent the entry of water vapor from the outside.

In addition, by providing the moisture-proof material 30 in the terminal region T, it is possible to effectively prevent the occurrence of deformation such as warpage and undulation in the

plastic substrates

6 and 8 due to the penetration of water vapor. As a result, it is possible to prevent the connection reliability of the flexible printed circuit board 24 from being lowered.

As the moisture-proof material 30, as shown in FIG. 4, a laminated film in which an adhesive layer 31 and a water vapor barrier layer 32 are laminated can be used.

As the adhesive layer 31, a layer mainly composed of an insulating resin having adhesiveness can be used. As this insulating resin, for example, an epoxy resin, an acrylic resin, a silicone resin, or the like can be used.

The water vapor barrier layer 32 is not particularly limited as long as it is capable of barriering water vapor, but a metal film or an inorganic film is used as a material for forming such a water vapor barrier layer 32. Can do.

Here, as the metal film, for example, a film made of SUS, aluminum, or the like can be used. As the inorganic film, a film made of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, aluminum oxide, or the like can be used. In addition, these may be used independently and may mix and use 2 or more types.

Further, the thickness of the water vapor barrier layer 32 is preferably 10 nm to 20 μm. This is because when the thickness is less than 10 nm, the water vapor barrier layer 32 is too thin, so that the water vapor barrier performance may not be sufficiently exhibited. Moreover, when larger than 20 micrometers, it is because the water vapor | steam barrier layer 32 becomes difficult to bend | curve and adhesion | attachment may become difficult.

And by adhering the water vapor barrier layer 32 to the outer surface of the TFT substrate 2 and the outer surface of the flexible printed circuit board 24 through the adhesive layer 31, so as to seal the terminal 9 in the terminal region T, A moisture-proof material 30 that covers the TFT substrate 2 and the flexible printed circuit board 24 is provided.

Next, a method for manufacturing a liquid crystal display device according to an embodiment of the present invention will be described. 5 to 11 are cross-sectional views for explaining a method of manufacturing a liquid crystal display device according to the embodiment of the present invention. The manufacturing method shown below is merely an example, and the liquid crystal display device according to the present invention is not limited to the one manufactured by the method shown below.

<TFT substrate manufacturing process>
First, as shown in FIG. 5, for example, a glass substrate 17 having a thickness of about 0.7 mm is prepared as a support substrate.

Next, as shown in FIG. 5, a film-like flexible plastic substrate 6 made of, for example, polyimide resin is formed on the glass substrate 17 with a thickness of about 20 μm, for example.

Next, TFTs, pixel electrodes, terminals 9 and the like are patterned on the plastic substrate 6 to form the display element layer 7 as shown in FIG. Next, a polyimide resin is applied to the entire substrate by a printing method, and then a rubbing process is performed to form an alignment film. Next, for example, spherical silica or plastic particles are dispersed over the entire substrate to form spacers.

As described above, the TFT substrate 2 constituting the display region D and the terminal region T can be manufactured.

<CF substrate manufacturing process>
First, as shown in FIG. 6, for example, a glass substrate 18 having a thickness of about 0.7 mm is prepared as a support substrate. Next, as shown in FIG. 6, a film-like flexible plastic substrate 8 made of, for example, polyimide resin is formed on the glass substrate 18 with a thickness of about 20 μm, for example.

Next, a color filter including a colored layer and a black matrix is formed on the plastic substrate 8, and an overcoat layer, a common electrode, and the like are patterned to form a CF element layer 19. Thereafter, a polyimide resin is applied to the entire substrate by a printing method, a rubbing process is performed, and an alignment film is formed, whereby the CF substrate 3 constituting the display region D is manufactured.

The black matrix is made of metal materials such as Ta (tantalum), Cr (chromium), Mo (molybdenum), Ni (nickel), Ti (titanium), Cu (copper), and Al (aluminum), and black pigments such as carbon. Are dispersed or a resin material in which a plurality of colored layers having light transmittance are laminated.

<TFT substrate / CF substrate bonding process>
First, for example, using a dispenser, the sealing material 5 made of ultraviolet curing and thermosetting resin or the like is drawn on the CF substrate 3 in a frame shape.

Next, a liquid crystal material for forming the liquid crystal layer 4 is dropped on a region inside the sealing material 5 in the CF substrate 3 on which the sealing material 5 is drawn.

Further, the CF substrate 3 onto which the liquid crystal material is dropped and the TFT substrate 2 are bonded together under reduced pressure.

Next, the front and back surfaces of the bonded body are pressurized by releasing the bonded body to atmospheric pressure. Next, after irradiating the sealing material 5 sandwiched between the bonded bodies with UV light, the sealing material 5 is cured by heating the bonded body, and as shown in FIG. 7, the TFT substrate 2 and the CF substrate 3 A bonded body in which is bonded is produced.

<Glass plate peeling process>
Next, as shown in FIG. 8, the glass substrate 17 is peeled off by irradiating laser light (arrows in FIG. 8) from the glass substrate 17 side. Here, the removal of the glass substrate 17 may not be peeling by laser light irradiation. For example, the glass substrate 17 may be removed using a polishing and etching apparatus.

Next, as shown in FIG. 9, the glass substrate 18 is peeled off by irradiating laser light (arrows in FIG. 9) from the glass substrate 18 side. Here, the removal of the glass substrate 18 may not be peeling by laser light irradiation as in the case of the glass substrate 17 described above. For example, the glass substrate 18 may be removed using a polishing and etching apparatus.

<Flexible printed circuit board connection process>
Next, as shown in FIG. 10, in the terminal region T, the terminal 9 formed on the TFT substrate 2 and the terminal 25 formed on the flexible printed circuit board 24 with the flexible printed circuit board 24 facing down (face down). The TFT substrate 2 and the flexible printed circuit board 24 are aligned with the conductive adhesive layer 16 interposed between the TFT substrate 2 and the flexible printed circuit board 24 so as to be connected to each other.

Next, as shown in FIG. 11, the terminals 25 formed on the flexible printed circuit board 24 are placed on the conductive adhesive layer 16. Then, with the conductive adhesive layer 16 heated to a predetermined curing temperature (for example, 180 ° C.), the conductive adhesive layer 16 is moved toward the TFT substrate 2 with a predetermined pressure (via the flexible printed circuit board 24). For example, the conductive adhesive layer 16 is heated and melted by pressurizing at 3 MPa.

As described above, since the conductive adhesive layer 16 is mainly composed of a thermosetting resin, it softens once when heated at a predetermined curing temperature, but is cured by continuing the heating. It will be. And when the preset curing time of the conductive adhesive layer 16 elapses, the state of maintaining the curing temperature of the conductive adhesive layer 16 is released, and cooling is started, so that the conductive adhesive layer 16 is passed through the conductive adhesive layer 16. , Terminal 9 and terminal 25 are connected. Then, in the terminal region T, the TFT substrate 2 and the flexible printed circuit board 24 are bonded together via the conductive adhesive layer 16 having adhesiveness, and the conductive adhesive layer 16 and the

terminals

9 and 25 are interposed. The TFT substrate 2 and the flexible printed circuit board 24 are electrically connected, and the TFT substrate 2 and the flexible printed circuit board 24 become conductive.

<Dampproof material pasting process>
Next, as shown in FIG. 12, in the terminal region T of the liquid crystal display device 1, the moisture-proof material 30 made of a laminated film in which the adhesive layer 31 and the water vapor barrier layer 32 are laminated is applied to the TFT substrate 2 and the flexible printed substrate 24. The terminal 9 is sealed with a moisture-proof material 30.

Then, a polarizing plate (not shown) and a backlight unit (not shown) are provided to complete the liquid crystal display device 1 shown in FIGS.

In the present embodiment described above, the following effects can be obtained.

(1) In this embodiment, the TFT substrate 2 and the flexible printed circuit board 24 are bonded together via the conductive adhesive layer 16 containing conductive particles, and the terminals 9 and the flexible print formed on the TFT substrate 2 are bonded together. The terminal 25 formed on the substrate 24 is electrically connected. And in the terminal area | region T, it is set as the structure which provides the moisture proof material 30 which covers the TFT substrate 2 and the flexible printed circuit board 24 so that the terminal 9 may be sealed. Therefore, heat and pressure treatment is performed to connect the flexible printed circuit board 24 to the terminal region T of the TFT substrate 2 including the plastic substrate 6, and the

terminals

9 and 25 are made conductive through the conductive adhesive layer 16. At that time, even if the conductive particles contained in the conductive adhesive layer 16 bite into the terminals 9 and cracks occur in the terminals 9, the terminals 9 are sealed by the moisture-proof material 30, Invasion of water vapor from the outside can be reliably prevented. Therefore, the terminal 9 can be prevented from being oxidized and insulated due to water vapor, and as a result, the occurrence of poor connection can be prevented and the connection reliability of the flexible printed circuit board 24 can be prevented from being lowered.

(2) Further, even when an anisotropic conductive adhesive layer containing conductive particles made of fine particles is used as the conductive adhesive layer, the terminal 9 is sealed by the moisture-proof material 30. Further, it is possible to reliably prevent water vapor from entering from the outside.

(3) In addition, by providing the moisture-proof material 30 in the terminal region T, it is possible to effectively prevent the occurrence of deformation such as warpage and undulation in the

plastic substrates

(4) In this embodiment, the moisture-proof material 30 is composed of a laminated film in which an adhesive layer 31 and a water vapor barrier layer 32 are laminated. Therefore, the moisture-proof material 30 can be formed with a simple configuration. Moreover, since the adhesive layer 31 is provided, the moisture-proof material 30 can be easily provided in the terminal region T.

(5) In the present embodiment, the water vapor barrier layer 32 is formed of a metal film or an inorganic film. Therefore, the water vapor barrier layer 32 can be formed with a simple configuration.

(6) In the present embodiment, the metal film is formed of SUS or aluminum. Accordingly, the metal film can be formed from a cheap and versatile metal material.

(7) In this embodiment, the inorganic film is formed of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, and aluminum oxide. Therefore, an inorganic film can be formed from an inexpensive and versatile inorganic material.

(8) In the present embodiment, the thickness of the water vapor barrier layer 32 is set to 10 nm to 20 μm. Therefore, the water vapor barrier layer 32 is difficult to bend, and the water vapor barrier performance can be sufficiently exhibited without causing the inconvenience that adhesion becomes difficult.

Note that the above embodiment may be modified as follows.

As in the liquid crystal display device 50 shown in FIG. 12, the inorganic film 33 may be provided on the surface 2a of the TFT substrate 2 on the liquid crystal layer 4 side. In this case, as shown in FIG. 12, the inorganic film 33 is provided between the TFT substrate 2 and the terminal 9 in the terminal region T.

By providing such an inorganic film 33, invasion of water vapor from the outside can be prevented more reliably in the terminal region T, and therefore, oxidation and insulation of the terminal 9 due to water vapor are further prevented. be able to. Further, in the display area D, it is possible to more effectively prevent the occurrence of deformation such as warpage and undulation in the

plastic substrates

6 and 8 due to the invasion of water vapor.

As a material for forming the inorganic film 33, a material made of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, aluminum oxide, or the like may be used as in the case of the inorganic film forming the water vapor barrier layer 32 described above. it can. In addition, these may be used independently and may mix and use 2 or more types.

In the terminal region T, when the inorganic film 33 is provided between the TFT substrate 2 and the terminal 9, heating is applied to connect the flexible printed circuit board 24 to the terminal region T of the TFT substrate 2 including the plastic substrate 6. When conducting pressure treatment and conducting the terminal 9 and the terminal 25 through the conductive adhesive layer 16, the conductive particles contained in the conductive adhesive layer 16 are not only the terminal 9 but also the inorganic film 33. It is conceivable that the inorganic film 33 is cracked by biting into the inorganic film 33. Even in this case, since the inorganic film 33 is sealed by the moisture-proof material 30, the entry of water vapor from the outside is surely prevented. be able to. Therefore, it is possible to prevent an insulation failure due to oxidation of the terminal 9 due to water vapor entering from the crack portion of the inorganic film 33.

Moreover, in the said embodiment, although the two-layer laminated | multilayer film by which the adhesive bond layer 31 and the water vapor | steam barrier layer 32 were laminated | stacked were used as the moisture-proof material 30, as a moisture-proof material 30, a 3 or more-layer laminated film is used. It is good also as composition to do. For example, as shown in FIG. 13, a base film 36 is provided between the adhesive layer 31 and the water vapor barrier layer 32, and the adhesive layer 31, the base film 36, and the water vapor barrier layer 32 are laminated. A laminated film may be used.

In addition, as the base film 36, for example, a film formed of polyethylene terephthalate resin or polyethylene resin can be used. By using such a base film, it is easily damaged in a thin film state and is difficult to handle. The water vapor barrier layer 32 can be protected and the water vapor barrier layer 32 can be easily handled.

In the present embodiment, the display device related to an LCD (liquid crystal display) is shown. However, the display device can be an organic EL (organic electroluminescence), electrophoresis (electrophoretic), PD (plasma display). Plasma display), PALC (plasma addressed liquid crystal display), inorganic EL (inorganic electroluminescence), FED (field emission display), or SED (surface-conduction electron-emitter display) It may be a display device related to an electric field display.

As described above, the present invention is particularly useful for a display device such as a liquid crystal display device provided with a plastic substrate.

1 Liquid crystal display device 2 TFT substrate (substrate for display device)
3 CF substrate (other display device substrate)
4 Liquid crystal layer (display medium layer)
6 Plastic substrate 6a Surface of the plastic substrate opposite to the side where the terminals are provided 7 Display element layer 9 Terminal 10 Laminate layer 12 Adhesive layer 14 Heat-resistant member 15 Deformation preventing member 16 Conductive adhesive layer 19 CF element layer 24 Flexible printed circuit board (drive circuit board)
25 terminals (other terminals)
30 Moisture-proof material 31 Adhesive layer 32 Water vapor barrier layer 33 Inorganic film D Display area T Terminal area

Claims

A display circuit board comprising a plastic substrate having flexibility and a display element layer formed on the plastic substrate, a display area for displaying an image, and a drive circuit board provided around the display area And a terminal region where a terminal to be connected is formed,
Display in which the display device substrate and the drive circuit substrate are bonded to each other via a conductive adhesive layer containing conductive particles, and the terminal and another terminal formed on the drive circuit substrate are electrically connected. A device,
In the terminal region, a moisture-proof material is provided to cover the display device substrate and the drive circuit substrate so as to seal the terminal.
The display device according to claim 1, wherein the conductive adhesive layer is an anisotropic conductive adhesive layer.
3. The display device according to claim 1, wherein the moisture-proof material is a laminated film in which an adhesive layer and a water vapor barrier layer are laminated.
4. The display device according to claim 3, wherein the water vapor barrier layer is formed of a metal film or an inorganic film.
The display device according to claim 4, wherein the metal film is made of SUS or aluminum.
The display device according to claim 4, wherein the inorganic film is made of at least one selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, and aluminum oxide.
The display device according to any one of claims 3 to 6, wherein the water vapor barrier layer has a thickness of 10 nm to 20 µm.
The display device according to any one of claims 1 to 7, wherein a base film is provided between the adhesive layer and the water vapor barrier layer.
The display according to any one of claims 1 to 8, wherein the plastic substrate is formed of one selected from the group consisting of a polyimide resin, a polyparaxylene resin, and an acrylic resin. apparatus.
Another display device substrate disposed opposite to the display device substrate;
10. The display device according to claim 1, further comprising a display medium layer provided between the display device substrate and the other display device substrate.
The display device according to claim 10, wherein the display medium layer is a liquid crystal layer.