JP3202537B2 - Tablet terminal - Google Patents

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 disposed in front of a display screen in a band shape.
The present invention relates to improvement of an insulating layer provided between the transparent electrode and the conductive pattern of the terminal.

[0002]

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

[0003] That is, when using such a tablet, the user presses an appropriate portion of the transparent film with a fingertip or a pen tip while watching the display contents of the display screen, and the pressed portion of the transparent film is bent, Since the transparent electrodes of both electrode substrates can be locally and selectively conductive, the coordinate signal of the pressed location according to the display content can be input, and therefore, the interactive input operation can be performed with a simple system configuration. It becomes executable.

By the way, a terminal portion of a tablet to be inserted into a connector does not originally need a transparent electrode. However, in actuality, a complicated process such as etching is omitted to reduce costs. Also, a 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 the insulating layer at a high hardness of about H in pencil hardness, the insulation pattern is formed by the pressing force exerted by the contact portion (metal contact) of the inserted connector. Care is taken not to undesirably reduce insulation resistance due to holes in the layer, that is, to prevent short-circuiting between the conductive pattern and the transparent electrode.

[0005] It should be noted that I for transparent films such as PET.
Since the adhesion of the transparent electrode such as TO is not so strong, if the insulating layer covering the transparent electrode on the transparent film is set to a higher hardness, the shrinkage rate of the insulating layer upon curing is excessively high. As a result, a problem occurs that the transparent electrode is easily peeled off from the transparent film as the base material. That is, if the transparent electrode is peeled off from the transparent film in this way, cracks are likely to be generated in the transparent electrode when handling the tablet, so that the reliability is significantly impaired.

[0006]

As described above, the terminal portion of the conventional tablet has a pencil hardness in consideration of the fact that the hardness of the insulating layer interposed between the transparent electrode and the conductive pattern is not too soft or too hard. Is set to about H, but according to a detailed investigation by the present inventors, even if an insulating layer having such a hardness is interposed between the transparent electrode and the conductive pattern, the pressure contact force of the connector causes In some cases, the insulating layer was perforated or the transparent electrode was peeled off from the transparent film due to shrinkage during curing of the insulating layer, and it was found that sufficient reliability was not always obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned deficiencies of the prior art, and an object thereof is to maintain good insulation resistance without forming a hole in an insulation layer even when receiving a press-contact force of a connector. It is another object of the present invention to provide a highly reliable tablet terminal that can prevent conduction failure without fear of the transparent electrode peeling off from the transparent film.

[0008]

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

[0009]

As described above, if the hardness of the first insulating layer provided on the transparent electrode is softened to B or F by pencil hardness, the shrinkage rate of the insulating layer at the time of curing is small. 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 second insulating layer provided on the first insulating layer is hardened by the pressing force of the connector via the conductive pattern. There is no need to worry about holes in the second insulating layer, and thus holes in the first insulating layer can be prevented.

[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 tablet terminal according to the present invention, cut along the longitudinal direction of the terminal part, and FIG. 2 is a connector connecting portion of the terminal part in the embodiment. FIG. 3 is a cross-sectional view of the terminal section taken along the width direction of the terminal portion.

In these figures, reference numeral 1 generally indicates a terminal portion, 2 is a transparent film made of polyethylene terephthalate (PET) or the like, and 3 is a transparent film made of ITO, ZnO or the like provided on the transparent film 2. Transparent electrodes, 4 and 5 are insulating layers, 6 is a conductive pattern made of silver or the like,
Reference numeral 7 denotes carbon, and 8 denotes 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. The conductive pattern 6 is provided on the transparent electrode 3 and covers the first insulating layer 4. The hardness is set to B to F by pencil hardness, 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 by pencil hardness. . The conductive pattern 6
Is covered with an overcoat layer 8 except for a tip portion to be connected to a connector (not shown). The carbon 7 covering the tip portion of the conductive pattern 6 prevents the silver from being altered and migrated due to oxidation or the like. This is to prevent it.

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 a polyester and a synthetic resin having a urethane bond at a terminal group, and a curing agent containing an isocyanate group and a terephthalic acid or the like. It is obtained by adding a curing accelerator containing an organic acid. However, the first insulating layer 4 has a small amount of a hardening agent or a hardening accelerator to reduce the surface hardness (softness), and the second insulating layer 5 has a hardening to increase the surface hardness (hardness). The amounts of additives and curing accelerators are increased. In this embodiment, the same material as that of the first insulating layer 4 is used for the overcoat layer 8.

Next, the overall structure of the tablet provided with the terminal unit 1 will be described.
One transparent electrode substrate provided with a transparent electrode on one surface of a transparent glass substrate and the other transparent electrode substrate provided with a transparent electrode 3 on one surface of a transparent film 2 are provided so that the transparent electrodes can be separated from each other. The two electrode substrates are overlapped so as to face each other via a transparent insulating spacer, and a transparent portion in which these two electrode substrates overlap is disposed on the front surface of a display screen such as a liquid crystal display device or a CRT. Further, the latter transparent electrode substrate having flexibility is extended in 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. Thereby, the user presses an appropriate portion of the transparent film 2 located on the front surface thereof with a fingertip or the like while viewing the display content on the display screen to locally and selectively conduct the transparent electrodes of both electrode substrates. Tablet input operation can be performed.

FIGS. 3 to 5 are views for explaining a manufacturing process of a flexible transparent electrode substrate provided with the terminal portion 1. First, a predetermined shape of the transparent electrode 3 provided on one side in advance is used. A transparent film 2 is prepared, and on the transparent electrode 3,
Except for the operation region 9 and the connection region 10 with the conductive pattern 6, the first insulating layer 4 is printed and cured as shown in FIG. 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 hardened have different addition amounts of the hardener and the hardening accelerator as described above, the first insulating layer 4 is formed to have a pencil hardness of B to F and has a softness. The second insulating layer 5 is formed to have a pencil hardness of 2H or more. Next, as shown in FIG. 4, a 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. Such a conductive pattern 6
In the present embodiment, a total of four electrodes are formed, which are composed of two film-side electrode patterns 6a connected to the transparent electrode 3 on the transparent film 2 and led out to the terminal 1 side, and a glass substrate. And two electrode patterns 6b for connecting a transfer for guiding a glass-side electrode pattern (both not shown) connected to the transparent electrode to the terminal portion 1 side. Thereafter, 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 silver alteration and migration. Further, as shown in FIG. 5, the overcoat layer 8 is printed except for the connector connection portion and the operation region 9 to secure the surface insulation. In order to enhance the insulating property, two to three overcoat layers 8 may be formed. Further, the cross-sectional view of FIG. 2 described above is obtained when the terminal portion 1 is cut along the line AA in FIG.

As described above, according to the present embodiment, the first insulating layer 4 which directly covers the transparent electrode 3 provided on the transparent film 2 is set to be softer with a pencil hardness of B to F. Therefore, the shrinkage ratio of the insulating layer 4 during curing is small, and there is no fear that the transparent electrode 3 is peeled off from the transparent film 2 when the insulating layer 4 is cured. Therefore, the risk of causing cracks in the transparent electrode 3 when handling the tablet is greatly reduced as compared with the conventional product, and improvement in reliability is expected. Further, a second insulating layer provided on the first insulating layer 4 is formed.
Since the insulating layer 5 is set to have a pencil hardness of 2H or more, there is no fear that a hole is formed in the second insulating layer 5 which receives the press-contact force of the connector via the conductive pattern 6. Holes in the insulating layer 4 can also be prevented. Therefore, terminal part 1
After the connector is inserted into the connector, there is no fear that the first and second insulating layers 4 and 5 become extremely thin due to the pressing force of the connector.
Good insulation resistance can be maintained.

[0017]

As described above, the terminal portion of the tablet according to the present invention is provided with a conductive pattern on a transparent electrode provided on a transparent film via two insulating layers, of which a conductive pattern is provided on the transparent electrode. Since the hardness of the first insulating layer provided is made small and the hardness of the second insulating layer provided on the first insulating layer is made large, there is no fear that the transparent electrode is peeled off from the transparent film. In addition to this, there is an excellent effect that even if the connector is subjected to a pressure contact force, a hole is not formed in the insulating layer, good insulation resistance is maintained, and reliability is significantly improved.

[Brief description of the 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, taken along a longitudinal direction of the terminal portion.

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

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

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

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

[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

──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-A-60-258631 (JP, A) JP-A-1-206425 (JP, A) JP-A-6-195176 (JP, A) JP-A 8- 321255 (JP, A) JP-A-7-22221 (JP, A) JP-A-6-61490 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G06F 3/03 G06F 3 / 033-3/037 G02F 1/1343-1/1365

Claims (2)

(57) [Claims] 1. A flexible terminal portion provided with a conductive pattern on a transparent electrode provided on a transparent film via two insulating layers, and used by being inserted into a connector. A terminal portion of a tablet, wherein a hardness of a first insulating layer provided thereon is smaller than a hardness of a second insulating layer provided on the first insulating layer. 2. The method 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 section of the tablet.