JPH08328721A - Terminal part for tablet - Google Patents

Abstract

PURPOSE: To maintain improved insulation resistance without piercing an insulation layer even when the pressure contact force of a connector is received, to eliminate the probability of the peeling off of a transparent electrode from a transparent film and to prevent conducting defects by making the hardness of a first insulation layer provided on the transparent electrode weaker than the hardness of a second insulation layer. CONSTITUTION: A conductive pattern 6 is formed through the two insulation layers which are the first insulation layer 4 and the second insulation layer 5 on the transparent electrode 3 of this terminal part 1. Then, the hardness of the first insulation layer 4 provided on the transparent electrode 3 for covering the electrode 3 is set to the B or F of pencil hardness and the hardness of the second insulation layer 5 provided on the first insulation layer 4 for covering the insulation layer 4 is set to be more than 2H of the pencil hardness. Also, the conductive pattern 6 is covered with an overcoating layer 8 excluding a tip to be connected to the connector. Also, carbon 7 for covering the tip of the conductive pattern 6 is to prevent the degeneration and migration of silver by oxidation or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible terminal portion formed by extending one of opposing transparent electrode substrates of a tablet arranged in front of a display screen in a strip shape, and more particularly,
The present invention relates to improvement of an insulating layer provided between the transparent electrode of the terminal portion and the conductive pattern.

[0002]

2. Description of the Related Art A tablet is generally made of a transparent glass substrate, one side of which is provided with a transparent electrode such as ITO or ZnO, and polyethylene terephthalate (PE).
T) and the other transparent electrode substrate having a transparent electrode provided on one surface of the transparent film are overlapped with a transparent insulating spacer so that the transparent electrodes face each other so that they can come into contact with and separate from each other. The latter transparent electrode substrate having the property is extended in a strip shape to form a terminal portion. And at the time of use,
A transparent portion where both electrode substrates overlap is placed in front of the display screen of a liquid crystal display device or a CRT so that the display screen can be viewed through a tablet.
The flexible terminal portion is inserted into the connector and connected to an external circuit.

That is, when such a tablet is used, a user presses an appropriate portion of the transparent film with a fingertip or a pen tip while observing the display contents on the display screen, and the portion where the transparent film is pressed is bent, Since the transparent electrodes of both electrode substrates can be locally and selectively conducted, the coordinate signal of the pressed point according to the displayed contents can be input, and the interactive input operation can be performed with a simple system configuration. It becomes feasible.

By the way, the terminal portion of the tablet inserted into the connector originally does not require a transparent electrode, but in reality, in order to reduce the cost by omitting a complicated process such as etching, the terminal portion is required. Also in, the transparent electrode is provided on one surface of the transparent film. Therefore, in the terminal portion of the conventional tablet, a transparent electrode such as ITO provided on a transparent film such as PET is covered with an insulating layer, and silver or the like derived from the transparent electrodes of both electrode substrates is coated on the insulating layer. By forming a conductive pattern made of, and setting the insulation layer to a high hardness of H in terms of pencil hardness, the insulation is provided by the pressure contact force exerted by the contact portion (metal contact) of the inserted connector. The layers are provided with holes so that the insulation resistance does not undesirably decrease, that is, the conductive pattern and the transparent electrode do not cause a short circuit.

I for transparent films such as PET
Since the adhesion of transparent electrodes such as TO is not so strong, when the insulating layer covering the transparent electrodes on the transparent film is set to have a higher hardness, the shrinkage rate of the insulating layer during curing becomes excessive. As a result, the transparent electrode easily peels off from the transparent film as the base material. That is, if the transparent electrode is peeled off from the transparent film in this manner, cracks are likely to occur in the transparent electrode during handling of the tablet, and the reliability is significantly impaired.

[0006]

As described above, the conventional tablet terminal portion has a pencil hardness in consideration of the hardness of the insulating layer interposed between the transparent electrode and the conductive pattern, not being too soft or too hard. However, according to a detailed investigation by the present inventors, even if an insulating layer having such hardness is interposed between the transparent electrode and the conductive pattern, the pressure contact force of the connector causes It has been found that sufficient reliability cannot always be obtained because the transparent electrode may peel off from the transparent film due to holes in the insulating layer or contraction of the insulating layer during curing.

The present invention has been made in order to solve the deficiency of the prior art, and its purpose is to maintain a good insulation resistance without forming holes in the insulating layer even when the pressure contact force of the connector is applied. Another object of the present invention is to provide a highly reliable terminal portion of a tablet in which there is no concern that the transparent electrode is peeled off from the transparent film and conduction failure can be prevented.

[0008]

The above-mentioned object of the present invention is to provide a conductive pattern on a transparent electrode provided on a transparent film via two insulating layers, of which the transparent electrode is provided on the transparent electrode. This is achieved by making the hardness of the first insulating layer to be provided smaller than the hardness of the second insulating layer provided on the first insulating layer. Specifically, the pencil hardness of the first insulating layer is set to B to F, and the hardness of the second insulating layer is
The hardness of the insulating layer may be set to a pencil hardness of 2H or more.

[0009]

As described above, if the hardness of the first insulating layer provided on the transparent electrode is set to be B to F in terms of pencil hardness, the insulating layer has a small shrinkage factor upon curing, so that the transparent electrode is It becomes difficult to peel off from the transparent film, and if the hardness of the second insulating layer provided on the first insulating layer is set to a pencil hardness of 2H or more, the pressure contact force of the connector is applied via the conductive pattern. There is no concern that the second insulating layer will have holes, so that it is possible to prevent perforation of the first insulating layer.

[0010]

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

FIG. 1 is a sectional view of an essential part of an embodiment of a terminal portion of a tablet according to the present invention cut along the longitudinal direction of the terminal portion, and FIG. 2 is a connector connecting portion of the terminal portion in the embodiment. FIG. 5 is a cross-sectional view of the terminal section cut along the width direction of the terminal section.

In these drawings, reference numeral 1 indicates a terminal portion as a whole, 2 is a transparent film made of polyethylene terephthalate (PET) or the like, and 3 is ITO or ZnO provided on the transparent film 2. Transparent electrodes, 4, 5 are insulating layers, 6 is a conductive pattern made of silver or the like,
Reference numeral 7 is carbon, and 8 is an insulating overcoat layer.
That is, in this embodiment, on the transparent electrode 3 of the terminal portion 1,
A conductive pattern 6 is formed via two insulating layers, a first insulating layer 4 and a second insulating layer 5, and is provided on the transparent electrode 3 to cover the electrode 3. The pencil hardness is set to B to F, and the hardness of the second insulating layer 5 provided on the first insulating layer 4 and covering the insulating layer 4 is set to 2H or more in pencil hardness. . The conductive pattern 6
Is covered with the overcoat layer 8 except for the tip portion to be connected to a connector (not shown), and the carbon 7 covering the tip portion of the conductive pattern 6 prevents the deterioration and migration of silver due to oxidation or the like. It is for prevention.

Regarding the first and second insulating layers 4 and 5,
More specifically, in the case of the present embodiment, both of these insulating layers 4 and 5 are made of polyester, which is a synthetic resin having a urethane bond at its terminal group, and a curing agent containing an isocyanate group and terephthalic acid. It is obtained by adding a curing accelerator containing an organic acid. However, the first insulating layer 4 is hardened in order to reduce (soften) the surface hardness by reducing the addition amount of the curing agent or the hardening accelerator, and the second insulating layer 5 is hardened in order to increase the surface hardness (harden). The amount of additives and curing accelerators is increased. In this embodiment, the same material as the first insulating layer 4 is used as the overcoat layer 8.

Next, the entire structure of the tablet provided with the above-mentioned terminal portion 1 will be described.
One transparent electrode substrate having a transparent electrode provided on one surface of a transparent glass substrate and the other transparent electrode substrate having a transparent electrode 3 provided on one surface of a transparent film 2 are configured so that their transparent electrodes can contact and separate from each other. The two electrodes are overlapped with each other via a transparent insulating spacer so as to face each other, and an externally transparent portion where these two electrode substrates overlap is arranged on the front surface of a display screen of a liquid crystal display device or a CRT. Also, the latter transparent electrode substrate having flexibility is formed into a strip shape to form the terminal portion 1, and the flexible terminal portion 1 is inserted into a connector and connected to an external circuit. As a result, the user, while watching the display content on the display screen, presses an appropriate portion of the transparent film 2 located on the front surface thereof with a fingertip or the like to locally and selectively conduct the transparent electrodes of both electrode substrates. You can perform input operations on the tablet.

FIGS. 3 to 5 are for explaining a manufacturing process of a flexible transparent electrode substrate with the terminal portion 1. First, a transparent electrode 3 having a predetermined shape is provided on one surface in advance. Prepare a transparent film 2, and on the transparent electrode 3,
The first insulating layer 4 is printed and cured as shown in FIG. 3, except for the operation region 9 and the connection region 10 with the conductive pattern 6. Next, the second insulating layer 5 is printed and cured in the same shape on the cured first insulating layer 4. Since the two insulating layers 4 and 5 thus cured have different amounts of the curing agent and the curing accelerator added as described above, the first insulating layer 4 is formed to have a pencil hardness of B to F. The second insulating layer 5 is formed to have a pencil hardness of 2H or more. Next, as shown in FIG. 4, silver paste is printed in a predetermined shape on the second insulating layer 5 and on the connection region 10 where the transparent electrode 3 is exposed to form a conductive pattern 6. The conductive pattern 6 is
In this embodiment, a total of four films are formed. The breakdown is two film side electrode patterns 6a connected to the transparent electrodes 3 on the transparent film 2 and led out to the terminal portion 1 side, and on the glass substrate. Glass electrode pattern (both not shown) connected to the transparent electrode of (2) and two electrode patterns 6b for connecting a transfer for guiding to the terminal portion 1 side. Then, as shown in FIG. 4, on the conductive pattern 6 located at the tip portion (connector connection portion) of the terminal portion 1,
Carbon 7 is printed to prevent deterioration and migration of silver. Further, as shown in FIG. 5, the overcoat layer 8 is printed except for the connector connection portion and the operation area 9 to secure the surface insulation. In addition, in order to improve the insulating property, the overcoat layer 8 may be formed by stacking two or three layers. The cross-sectional view of FIG. 2 described above is taken when the terminal portion 1 is cut along the line AA of FIG.

As described above, according to this embodiment, the first insulating layer 4 which directly covers the transparent electrode 3 provided on the transparent film 2 is set to have a pencil hardness of B to F or soft. Therefore, the shrinkage rate of the insulating layer 4 at the time of curing is small, and therefore, when the insulating layer 4 is cured, the transparent electrode 3 does not have to be peeled off from the transparent film 2. Therefore, the risk of causing cracks in the transparent electrode 3 during handling of the tablet is greatly reduced compared to the conventional product, and reliability is expected to be improved. In addition, a second layer provided on the first insulating layer 4
Since the insulating layer 5 has a pencil hardness of 2H or more, the second insulating layer 5 which receives the pressure contact force of the connector through the conductive pattern 6 does not have a hole, and therefore the first insulating layer 5 has Perforation of the insulating layer 4 can also be prevented. Therefore, the terminal part 1
After inserting into the connector, there is no concern that the first and second insulating layers 4 and 5 become extremely thin due to the pressure contact force of the connector.
Good insulation resistance can be maintained.

[0017]

As described above, in the terminal portion of the tablet according to the present invention, the conductive pattern is provided on the transparent electrode provided on the transparent film via the two insulating layers, and the conductive pattern is provided on the transparent electrode. Since the hardness of the first insulating layer provided is reduced and the hardness of the second insulating layer provided on the first insulating layer is increased, there is no concern that the transparent electrode will peel off from the transparent film, and conduction failure will occur. This has an excellent effect that it can be prevented and a good insulation resistance can be maintained without a hole in the insulating layer even when receiving a pressure contact force of the connector, and the reliability is remarkably improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part of an embodiment of a terminal portion of a tablet according to the present invention, which is cut along a longitudinal direction of the terminal portion.

FIG. 2 is a cross-sectional view of the connector connecting portion of the terminal portion in the embodiment, taken along the width direction of the terminal portion.

FIG. 3 is an explanatory diagram showing a step of forming first and second insulating layers on the transparent electrode in the manufacturing process of the electrode substrate with terminals according to the example.

FIG. 4 is an explanatory view showing a step of forming a conductive pattern on the second insulating layer and forming carbon on the conductive pattern of the tip portion to be connected to the connector in the manufacturing process of the electrode substrate with terminals according to the embodiment. is there.

FIG. 5 is an explanatory diagram showing a step of forming an overcoat layer on a conductive pattern in the manufacturing process of the electrode substrate with terminals according to the example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Terminal part 2 Transparent film 3 Transparent electrode 4 First insulating layer 5 Second insulating layer 6, 6a, 6b Conductive pattern 7 Carbon 8 Overcoat layer 9 Operation area 10 Connection area

Claims (2)

[Claims] 1. A flexible terminal portion provided with a conductive pattern on a transparent electrode provided on a transparent film via two insulating layers, the flexible terminal portion being inserted into a connector for use. A terminal portion of a tablet, wherein a hardness of a first insulating layer provided on the upper side is smaller than a hardness of a second insulating layer provided on the first insulating layer. 2. The hardness according to claim 1, wherein the hardness of the first insulating layer is set to B to F in pencil hardness, and the hardness of the second insulating layer is set to 2H or more in pencil hardness. The terminal part of the tablet characterized by.