JPH06194680A - Liquid crystal substrate - Google Patents

Abstract

PURPOSE:To connect a liq. crystal substrate to the main circuit board and the display driving circuit board arranged close to the rear of the substrate by bending the substrate. CONSTITUTION:A film is coated with a transparent conductive film 5 to form a pattern circuit to constitute a liq. crystal substrate 1. The conductive film 5 is further coated with highly flexible conductive films 6 and 7 to form a reinforcing conductive layer by which the bent substrate 1 is mounted. Further, an insulating hot-melt adhesive 8 is applied on the remaining part except the pattern circuit. The reinforcing conductive layer is obtained by forming the conductive film 7 of carbon on the conductive film 6 of silver or the mixture of silver and carbon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal film substrate having a pattern wiring formed by depositing a transparent conductive film on the film surface.

[0002]

2. Description of the Related Art In recent years, a liquid crystal display device has been adopted as a display device in various kinds of equipment, and the liquid crystal is suitable for carrying because of its small size, light weight and low power consumption. Recently, a liquid crystal film substrate in which a transparent conductive film is coated on a transparent film is also used from the viewpoint of further weight reduction. Further, as a transparent conductive film, photo-etching can be performed relatively easily as compared with a NESA film made of a tin oxide (SnO2) film.
Indium oxide (In
An ITO film made of a 2O3) film is often used. IT like this
In a liquid crystal film substrate having a pattern wiring of an O film, conventionally, a heat seal connector formed by forming a pattern wiring having high flexibility is thermocompression bonded to the liquid crystal film substrate, and the heat seal connector is bent to form a liquid crystal. The terminals are connected by thermocompression bonding to the main circuit board and the display drive circuit board which are arranged close to the back side of the film board.

[0003]

As described above, the prior art is as follows.
Regarding the terminal connection between the liquid crystal film board and the circuit board arranged close to the back side, it has an indirect mounting structure using a heat seal connector, and the terminal is directly connected to the circuit board by bending the liquid crystal film board. I couldn't. That is, in the conventional liquid crystal film substrate, the pattern wiring due to the ITO film is broken when bent,
Further, there is a drawback that stress is applied to the terminal portion during thermocompression bonding, and the pattern wiring of the terminal portion may be broken.

Therefore, an object of the present invention is to provide a liquid crystal film substrate which can be connected to a circuit board in a state where the liquid crystal film substrate itself is bent.

[0005]

In order to solve the above problems, the present invention provides a liquid crystal film substrate having a pattern wiring formed by depositing a transparent conductive film on a film surface, wherein the pattern wiring is formed. A conductive film having excellent flexibility is further deposited on the transparent conductive film to form a reinforcing conductive layer that can be mounted in a state where the liquid crystal film substrate is folded. Specifically, an insulating hot melt adhesive is applied to the remaining portion other than the pattern wiring. Alternatively, a reinforcing material is bonded along the connection edge portion on the back surface side of the surface having the pattern wiring. For example, the reinforcing conductive layer has a two-layer structure in which a conductive film made of carbon alone is further formed on a conductive film made of silver alone or a mixture of silver and carbon. Further, for example, the reinforcing conductive layer has a one-layer structure made of a gold-plated conductive film.

[0006]

A transparent conductive film forming a pattern wiring is further coated with a conductive film having excellent flexibility to form a reinforcing conductive layer which can be mounted in a state where the liquid crystal film substrate is bent. Since it is a liquid crystal film substrate, even if the pattern wiring formed of the transparent conductive film is broken by bending, the conductive function of the pattern wiring is ensured by the reinforcing conductive layer formed of the conductive film having excellent flexibility. Therefore, the liquid crystal film substrate itself can be bent to directly connect terminals to the main circuit substrate and the display drive circuit substrate that are arranged close to the back surface side.

Further, in the remaining portion other than the pattern wiring,
By applying the insulating hot melt adhesive, the terminals of the liquid crystal film substrate can be directly connected to the terminals of the circuit substrate by thermocompression bonding. In addition, by bonding the reinforcing material along the connection edge on the back side of the surface having the pattern wiring, the terminal part to which the reinforcing material of the liquid crystal film substrate is bonded is directly connected to the connector provided on the terminal part of the circuit board. Can be plugged in and connected.

By forming a conductive film of carbon alone on the conductive film of silver alone or a mixture of silver and carbon, a reinforcing conductive layer having a two-layer structure is obtained.
It is possible to protect the front side by a carbon conductive film which is inexpensive and resistant to aging, while the conductive film having high flexibility including silver is closely adhered to the transparent conductive film for reinforcement. In addition, by using a reinforcing conductive layer having a one-layer structure made of a gold-plated conductive film, it is possible to obtain a surface layer that is highly flexible and resistant to aging.

[0009]

EXAMPLES Examples of the liquid crystal film substrate according to the present invention will be described below with reference to FIGS. First, in FIG. 1 showing a method of mounting a liquid crystal film substrate on a circuit board as an example to which the present invention is applied, 1 is a liquid crystal film substrate, 2 is a liquid crystal display portion, 3 and 4 are terminal portions, and 11 is a display drive. Circuit board, 12, 13, 14 are display drivers, 15,
16 is a terminal part.

As shown in FIG. 1, two liquid crystal film substrates 1 and 1 are attached to each other to form a liquid crystal display unit 2 in which a liquid crystal material is enclosed. The two liquid crystal film substrates 1 and 1 are flexible transparent film substrates formed of polyethylene terephthalate (PET) or polyether sulfone (PES). And, on these two liquid crystal film substrates 1 and 1,
Terminal portions 3 and 4 formed by extending one side portion in the intersecting direction are integrally provided respectively, and pattern wiring to be described later is formed on each film surface from the liquid crystal display portion 2 to the terminal portions 3 and 4. ing.

The display drive circuit board 11 is arranged close to the back side of the liquid crystal display section 2. The display drive circuit board 11 is provided with three display drivers 12, 13, and 14 in the illustrated example. Further, two adjacent side portions of the display drive circuit board 11 in the intersecting direction are terminal portions 15 and 16 connected to the display drivers 12, 13 and 14 and the like by pattern wiring (not shown).

In the above, the pattern wiring portions formed on the respective film surfaces from the liquid crystal display portion 2 of the two liquid crystal film substrates 1 and 1 to the terminal portions 3 and 4 are
It has the configuration shown in FIG. That is, as shown in FIG. 2, the pattern wiring is formed of an indium oxide (In2O3) film or an ITO film with a small amount of tin oxide (SnO2) added by an appropriate method such as photo-etching or using a mask. The transparent conductive film 5 deposited on the film surface
It consists of 5, 5, 5, 5, .... Then, along the transparent conductive films 5, 5, 5, 5, 5, ... By this ITO film,
For reinforcement, Ag conductive films 6, 6, 6, 6, 6, ... By screen printing of silver (hereinafter referred to as Ag) having low electric resistance and excellent flexibility are deposited.

Further, this Ag conductive film 6, 6, 6, 6,
Along the top of 6, ..., C conductive film 7 by screen printing of carbon (hereinafter, referred to as C), which similarly has low electric resistance and excellent flexibility, for further reinforcement and measures against aging. 7,7,7, ... are attached. Thus, the reinforcing conductive layer having a two-layer structure of the Ag conductive film 6 and the C conductive film 7 formed thereon is formed on the transparent conductive film 5 made of the ITO film. Further, on the film surface of the remaining portion other than the pattern wiring provided with such a reinforcing conductive layer, a highly insulating hot melt adhesive 8 by screen printing for thermocompression bonding connection of the terminals 3 and 4, 8,
It is wearing 8,8, ....

As described above, from the liquid crystal display section 2 to the terminal section 3,
ITO forming pattern wiring on each film surface to 4
Since the liquid crystal film substrates 1 and 1 are formed by forming a reinforcing conductive layer having a two-layer structure of an Ag conductive film 6 and a C conductive film 7 having low electric resistance and excellent flexibility on the transparent conductive film 5 made of a film, As shown in FIG. 1, the transparent conductive film 5 made of an ITO film is formed by bending each of the terminal portions 3 and 4 to the back surface side.
Even if the wire is disconnected, the conductive function of the pattern wiring can be secured by the two-layered Ag conductive film 6 and C conductive film 7 forming the reinforcing conductive layer. Therefore, the terminal portions 3 and 4 of the liquid crystal film substrates 1 and 1 are respectively bent to the back surface side and overlapped with the terminal portions 15 and 16 of the display drive circuit substrate 11, respectively, and the high insulating hot melt adhesive 8 by thermocompression bonding, The terminals can be directly connected by melting and solidifying 8,8,8, ....

By the way, in the above embodiments, the reinforcing conductive layer provided on the transparent conductive film 5 made of the ITO film has the two-layer structure of the Ag conductive film 6 and the C conductive film 7. Is a mixed paste of Ag and C (A
g + C) A two-layer structure composed of a conductive film and a C conductive film 7, or a one-layer structure composed of a conductive film of gold (hereinafter, referred to as Au) plating that is strong in flexibility and resistant to aging. Good.

Next, the second embodiment of the present invention shown in FIGS.
Examples will be described. First, in FIG. 3 showing how to mount the liquid crystal film substrate on the circuit board in the second embodiment, 21 is a liquid crystal film substrate, 22 is a liquid crystal display unit,
23, 24, 25 are terminal portions, 29 is a reinforcing material, 32, 3
3, 34 and 35 are display drivers, 41 is a main circuit board, and 43, 44 and 45 are connectors.

As shown in FIG. 3, as in the first embodiment, two flexible liquid crystal film substrates 21 and 21 formed of PET or PES are bonded to each other, and a liquid crystal material is placed inside them. Liquid crystal display part 2 with
2 Here, in the illustrated example, one liquid crystal film substrate 21 is integrally provided with a terminal portion 23 formed by extending a short side portion side in a direction intersecting with the other liquid crystal film substrate 21, and the other liquid crystal film substrate 21 is provided. On the board 21, a pair of terminal portions 24, which are also formed by extending the long side portion in the intersecting direction,
25 are integrally provided. On the two liquid crystal film substrates 21 and 21, pattern wirings, which will be described later, are formed on the respective film surfaces from the liquid crystal display portion 2 to the terminal portions 23, 24 and 25.

Further, the terminal portion 2 formed by extending the short side portion side.
A display driver 32 is mounted at a position along the liquid crystal display portion 22 side of the liquid crystal film substrate 21 including the pair of terminal portions 24, 25 with the long side portion extended.
In a position along the liquid crystal display unit 22 side of the liquid crystal film substrate 21 including the three display drivers 33,
34 and 35 are mounted. On the other hand, the display drive circuit board 41 arranged close to the back side of the liquid crystal display unit 22 is provided with a connector 43 on the short side and a pair of connectors 44 and 45 on the long side. .

In the above, the two liquid crystal film substrates 2
1, 21 liquid crystal display section 2 to terminal section 23 or terminal section 2
Pattern wirings are provided on the film surfaces of the films 4 and 25. FIG. 4 shows the details of the display driver 32 portion of the pattern wiring. As shown in the figure, the pattern wiring 26 has a fine pitch line on the effective display surface side of the liquid crystal display unit 22, and the main circuit board 41 and The pitch on the connection side of is large. The structure of the pattern wiring 26 is similar to that of the other display driver 33,
The same applies to the 34 and 35 parts.

Further, the display drivers 32, 33, 34,
The pattern wiring portion from 35 to the terminal portions 23, 24, 25 has the configuration shown in FIG. That is, as shown in FIG. 5, the pattern wiring is the same as in the first embodiment.
Transparent conductive films 26 and 2 in which an ITO film is attached to the film surface
6, 26, 26, 26 ,. And this IT
Transparent conductive film 26, 26, 26, 26, 26, which is an O film
.. along the top, similar to the first embodiment.
7, 27, 27, 27, 27, ... Are attached by screen printing.

Further, the Ag conductive films 27, 27, 2
C, C conductive films 28, 28, 28, 28, 28, ... Are deposited by screen printing along the tops of 7, 27, 27 ,. In this way, IT
As in the first embodiment, a reinforcing conductive layer having a two-layer structure of an Ag conductive film 27 and a C conductive film 28 formed thereon is formed on the transparent conductive film 26 made of an O film. In addition, the terminal portions 23, 2 provided with such a reinforcing conductive layer
On the back side of 4, 25, a strip-shaped reinforcing member 29, 2 made of an insulating film or the like along the end face for connector connection.
9 and 29 are provided by bonding.

As described above, also in the liquid crystal film substrates 21 and 21 according to the second embodiment of the present invention, the ITO film forming the pattern wiring on each film surface from the liquid crystal display portion 22 to the terminal portions 23, 24 and 25 is used. Ag on the transparent conductive film 26
Since the reinforcing conductive layer having a two-layer structure of the conductive film 27 and the C conductive film 28 is formed, the ITO film is formed by bending the respective terminal portions 23, 24, 25 to the back surface side as shown in FIG. Even if the transparent conductive film 26 is broken due to, the conductive function of the pattern wiring is ensured by the two-layered Ag conductive film 27 and C conductive film 28 forming the reinforcing conductive layer thereon, as in the first embodiment. can do. Therefore,
Terminal portions 23, 24, 25 of the liquid crystal film substrates 21, 21
Bend each to the back side and insert into the connectors 43, 44, 45 of the main circuit board 41,
Direct connection between terminals is possible.

By the way, also in the second embodiment, I
The reinforcing conductive layer provided on the transparent conductive film 26 of the TO film has a two-layer structure of the Ag conductive film 27 and the C conductive film 28. In addition, the reinforcing conductive layer is the same as that of the first embodiment. Similarly, it may have a two-layer structure of a (Ag + C) conductive film and a C conductive film 28, or a one-layer structure of an Au-plated conductive film.

In the above embodiments, as a method for forming the reinforcing conductive layer, the conductive member is printed by Ag printing + C printing, the two-layer structure is formed by (Ag + C) printing + C printing, and the one layer is formed by Au plating. Although the structure is used, the present invention is not limited to this, and another conductive member may be used, or the reinforcing conductive layer may be formed by another method.
Further, with respect to a device on which the liquid crystal film substrate according to the present invention is mounted, for example, an electronic notebook, pocket computer
It is needless to say that the data terminal and the like are arbitrary, and other specific detailed structures and the like can be appropriately changed.

[0025]

As described above, according to the liquid crystal film substrate of the present invention, a conductive film having excellent flexibility is further deposited on the transparent conductive film forming the pattern wiring, and the liquid crystal film substrate is formed. Since a reinforcing conductive layer that can be mounted in a bent state is formed, even if the pattern wiring of the transparent conductive film is broken due to bending, the reinforcing conductive film attached on it can be used for reinforcement. The conductive layer can ensure the conductive function of the pattern wiring. Therefore, it is possible to bend the liquid crystal film substrate itself and directly connect the terminals to the main circuit substrate and the display drive circuit substrate arranged close to the back surface side.

That is, the terminals of the liquid crystal film substrate are directly thermocompression-bonded to the terminals of the circuit substrate by applying an insulating hot melt adhesive to the remaining portion other than the pattern wiring as in claim 2. Can be connected by. Further, as described in claim 3, by bonding the reinforcing material along the connection edge portion on the back surface side of the surface having the pattern wiring, the terminal portion of the liquid crystal film substrate to which the reinforcing material is bonded is directly connected to the circuit board. It can be connected by inserting it into the connector provided on the terminal part.

According to a fourth aspect of the present invention, a reinforcing conductive layer having a two-layer structure is formed by further forming a conductive film made of carbon alone on a conductive film made of silver alone or a mixture of silver and carbon. While the conductive film having high flexibility including silver is adhered to the transparent conductive film to reinforce it, the front side thereof can be protected by the carbon conductive film which is inexpensive and resistant to aging. When the reinforcing conductive layer having a one-layer structure made of a gold-plated conductive film is used as in claim 5, a surface layer having high flexibility and resistance to aging can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic exploded perspective view showing a first embodiment, showing a method of mounting a liquid crystal film substrate on a circuit board as an example to which the present invention is applied.

FIG. 2 is an enlarged sectional view of an essential part showing a detailed structure of a terminal portion of the liquid crystal film substrate.

FIG. 3 is a schematic exploded perspective view showing a second embodiment showing a method of mounting a liquid crystal film substrate on a circuit board as another example to which the present invention is applied.

FIG. 4 is an enlarged perspective view of an essential part showing details of a B part in FIG.

FIG. 5 is an enlarged sectional view of an essential part showing a detailed structure of a terminal portion of a liquid crystal film substrate in a second embodiment.

[Explanation of symbols]

 1 Liquid crystal film substrate 2 Liquid crystal display part 3,4 Terminal part 5 Transparent conductive film (ITO film) 6,7 Reinforcing conductive layer 8 Insulating hot melt adhesive 11 Circuit board 12,13,14 Display driver 15,16 Terminal part 21 liquid crystal film substrate 22 liquid crystal display part 23, 24, 25 terminal part 26 transparent conductive film (ITO film) 27, 28 reinforcing conductive layer 29 reinforcing material 32, 33, 34, 35 display driver 41 circuit board 43, 44, 45 connector

Claims (5)

[Claims] 1. A liquid crystal film substrate having a pattern wiring formed by depositing a transparent conductive film on a film surface, further comprising a conductive film having excellent flexibility on the transparent conductive film forming the pattern wiring. A liquid crystal film substrate having a conductive conductive layer formed thereon, which is adhered to the liquid crystal film substrate so that it can be mounted in a bent state. 2. The remaining portion other than the pattern wiring is
The liquid crystal film substrate according to claim 1, wherein an insulating hot melt adhesive is applied. 3. The liquid crystal film substrate according to claim 1, wherein a reinforcing material is adhered along the connection edge portion on the back surface side of the surface having the pattern wiring. 4. The reinforcing conductive layer has a two-layer structure in which a conductive film made of carbon alone is further formed on a conductive film made of silver alone or a mixture of silver and carbon. 2. The liquid crystal film substrate according to 2 or 3. 5. The liquid crystal film substrate according to claim 1, wherein the reinforcing conductive layer has a single-layer structure made of a gold-plated conductive film.