JP2012194610A - Resistive film type touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resistive film type touch panel which can reduce a difference in thickness generated in a connection part of an FPC cable which is to be connected to a control substrate.SOLUTION: In a resistive film type touch panel, lower and upper electrode substrates 11a and 11b are installed face-to-face across an internal clearance. Thin-film transparent electrodes are sandwiched by the lower and upper electrode substrates 11a and 11b so as to electrically connect with respective thin-film transparent electrodes on the lower and upper electrode substrates 11a and 11b. An FPC cable is connected with the lower and upper electrode substrates 11a and 11b by thermo-compression bonding using an ACF 5 (anisotropic conductive adhesive film). The upper electrode substrate 11b is laminated by a cover film 2, and is provided with pieces of level difference reduction means (slits 7) for reducing a level difference due to a thickness of the FPC cable 3.

Description

  The present invention relates to a resistive film type touch panel, and more particularly, to a resistive film type touch panel that can reduce a thickness step generated at a joint portion of an FPC cable to be connected to a control board.

In recent years, touch panels have been widely used as input devices for various electronic devices and information terminal devices such as personal computers and mobile phones.
The touch panel is an instruction to input the two-dimensional coordinate data required for the display device when the operator touches a desired position on the panel surface with a pen or a finger. Widely used.
Among such touch panels, the resistive film type touch panel has a transparent electrode substrate having a transparent conductive film such as ITO (alloy of indium and tin oxide) facing up and down, and further extracts signals to the outside. In this state, the outer frame portion is fixed via a gap in a state where the wiring portion is sandwiched.
A voltage is applied to one of the upper and lower transparent electrode substrates, and the other transparent electrode substrate plays a role of potential detection.
By depressing the upper transparent electrode substrate among such upper and lower transparent electrode substrates, the depressing position is derived by detecting the potential at the location where the upper and lower transparent electrode substrates are in contact. Printed wiring with conductive ink is applied to the outer frame part of each electrode surface of the upper and lower transparent electrode substrates, and potential distribution is applied to the transparent electrode substrate via the printed wiring through the wiring part sandwiched between the upper and lower transparent electrode substrates. Alternatively, the potential is detected.

By the way, in an electronic device using a touch panel, in recent years, design is also regarded as important, and various attempts have been made.
For example, Patent Document 1 deals with the loss of the design concept that comes from the flow of so-called flat surfaces without the appearance of the equipment and the surface steps. That is, in Patent Document 1, when the touch panel is exposed on the surface of the casing, a step between the casing and the touch panel appears, so that the film member follows the step at the boundary between the main surface of the input panel and the cover member. By adhering to, the step is relaxed, and the deterioration of the design property due to the step is prevented.

  However, in the method according to Patent Document 1, the step is not completely eliminated, and the number of necessary components increases, and the film member is bonded to the main surface of the input panel as the operation surface by heat welding. The number of processes is large and complicated, and the manufacturing cost is inevitable.

Therefore, as described above, not only the assembly structure when the touch panel is incorporated into the electronic device casing, but also intensive studies and attempts have been made toward the flat surface from the structure of the touch panel itself.
In this case, in the resistive touch panel, an FPC cable capable of suppressing the thickness is adopted as the wiring portion for taking out the signal to the outside, and the outer and lower electrode substrates are placed outside through the gap in a sandwiched state. The frame portion is joined by thermocompression bonding using ACF (anisotropic conductive adhesive film) so that the influence of the thickness of the FPC cable does not appear on the touch panel surface.

JP 2008-257494 A

However, even in the resistive touch panel having the above-described structure, the crimped portion of the FPC cable using the ACF (anisotropic conductive adhesive film) is the thickness of the FPC cable itself and the upper portion around the FPC portion at the time of thermocompression bonding. Due to the deformation of the electrode film, it becomes thicker than the other parts, resulting in a step.
Accordingly, when a decorative cover film is bonded to the touch panel surface having such a structure, the flatness of the FPC portion is impaired.
The present invention has been proposed in order to improve the above-described problems, and has a structure in which a thickness step generated at a joint portion of an FPC cable to be connected to a control board can be relaxed. An object is to provide a touch panel.

 In order to solve the above-described problem, in the invention according to claim 1, the first electrode substrate and the second electrode substrate in which the conductive film is laminated on each one surface are made to face each other with the conductive film formation surface, and these With the first and second electrode substrates spaced apart from each other, a wiring portion for taking out signals is sandwiched between the conductive films of the first electrode substrate and the second electrode substrate and bonded together. The resistive touch panel includes a cover film bonded to the outer surface of the first or second electrode substrate, and a step leveling means for reducing the level difference due to the thickness of the wiring portion. To do.

  As a result, the entire cover film surface can suppress the influence of the step due to the thickness of the wiring part at the clamping part of the wiring part on the cover film surface at the clamping part of the wiring part. It is possible to provide a touch panel that is aimed at making it easier.

  Further, the invention according to claim 2 is characterized in that the step relief means is a step relief slit formed in the first electrode substrate or the second electrode substrate covering the wiring portion.

  Thereby, it can suppress that the influence of the level | step difference resulting from the thickness of the wiring part of the clamping part of a wiring part reaches the cover film surface of the clamping part of a wiring part.

  Further, in the invention according to claim 3, the step relief means is provided so as to alleviate a step between the sandwiched portion of the wiring portion and a portion other than the sandwiched portion of the wiring portion on the back surface of the cover film. It is a layer.

  As a result, the step mitigation layer can compensate for the step caused by the thickness of the wiring part at the clamping part of the wiring part, and on the cover film surface of the clamping part of the wiring part, the wiring part of the clamping part of the wiring part It is possible to suppress the influence of the step due to the thickness.

  The invention according to claim 4 is characterized in that the step-relief layer is interposed in a bonding portion other than the holding portion of the wiring portion in the first electrode substrate and the second electrode substrate.

  Thereby, it can suppress that the influence of the level | step difference resulting from the thickness of the wiring part of the clamping part of a wiring part reaches the whole cover film surface.

  Further, in the invention according to claim 5, the step reducing means is an adhesive that is used in a part other than the sandwiching part of the wiring part in order to bond the cover film to the outer surface of the first or second electrode substrate. It is characterized by that.

  Thereby, the adhesive is doubled to the thickness of the cover film at a portion other than the sandwiched portion of the wiring portion, and it is possible to suppress the influence of the step due to the thickness of the wiring portion from reaching the cover film surface.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that the influence by the level | step difference resulting from the thickness of the wiring part of the clamping part of a wiring part reaches the whole cover film surface, and provides the touch panel toward flat surface formation. be able to.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic exploded perspective view showing an embodiment of a resistive film type touch panel according to the present invention. It is typical plane explanatory drawing of the resistive film type touch panel shown in FIG. FIG. 2 is a cross-sectional explanatory view taken along line AA of the resistive touch panel shown in FIG. 1. It is typical explanatory drawing for demonstrating one Embodiment of the level | step difference mitigation means used with the resistive film type touch panel of this invention. It is typical explanatory drawing for demonstrating another embodiment of the level | step difference mitigation means used with the resistive film type touch panel of this invention. It is typical explanatory drawing for demonstrating another embodiment of the level | step difference mitigation means used with the resistive film type touch panel of this invention.

Hereinafter, a resistive film type touch panel according to the present invention will be described in detail with reference to the accompanying drawings with an embodiment.
1 and 2 show a resistive film type touch panel 1.
This resistive touch panel 1 has a cover film 2 with an appropriate decorative portion D (design printing of patterns, characters, etc.) on the upper surface of the touch panel body 11 in the drawing, aiming at flattening the outer surface, that is, flat surface. It is configured by pasting together.
The touch panel body 11 includes a first electrode substrate 11a and a second electrode substrate 11b in which a conductive film (for example, a transparent conductive film such as ITO (an alloy of indium and tin oxide)) is laminated on one surface. The first and second electrode substrates 11a and 11b have the conductive film forming surfaces facing each other, and the first and second electrode substrates 11a and 11b are separated from each other via an outer frame portion 11E with a gap therebetween. They are bonded together (described later).
In addition, an electrode portion (not shown) is disposed on the conductive film formation surface side of the first and second electrode substrates 11a and 11b, and the electrode portion is interposed between the respective conductive films on the first and second electrode substrates 11a and 11b. A wiring part 3 (hereinafter referred to as an FPC cable 3) for taking out a signal is sandwiched between the first and second electrode substrates 11a and 11b and bonded together using an adhesive 4 along the outer frame part 11E. In addition, the electrode portions of the first and second electrode substrates 11a and 11b and the FPC cable 3 are connected by thermocompression bonding using the anisotropic conductive adhesive film 5 (see FIG. 3).

  In the present embodiment, the first and second electrode substrates 11a and 11b are constituted by lower and upper transparent electrode substrates 11a and 11b, respectively. Hereinafter, the lower and upper transparent electrode substrates 11a and 11b will be described.

The lower transparent electrode substrate 11a is formed, for example, by forming a transparent conductive film 6 such as ITO (an alloy of indium and tin oxide) on a rectangular glass substrate (see FIG. 3).
On the transparent conductive film, although not shown, a thin film transparent electrode formed in a band pattern by printing using a silver-containing conductive ink material or a carbon-containing conductive ink material is provided. Yes.
In addition to the glass substrate, the lower transparent electrode substrate 11a is preferably made of a resin material that has high light transmittance, excellent molding accuracy, and is hard. Examples of the resin material include polyethylene terephthalate (PET), polyethersulfone (PES), polyetheretherketone (PEEK), polycarbonate (PC), polypropylene (PP), and polyamide (PA).

The upper transparent electrode substrate 11b is made of a resin material (for example, polyethylene terephthalate PET) having the same area as the lower transparent electrode substrate 11a, and the transparent conductive film 6 such as ITO (alloy of oxide of indium and tin) is vacuum deposited. The film is formed by a method, a sputtering method, a CVD method, a printing method, or the like.
The upper transparent electrode substrate 11b is provided with a thin film transparent electrode formed in a band pattern by printing on the lower surface side of the lower transparent electrode substrate 11a opposite to the upper surface where the thin film transparent electrode is formed.

The FPC cable 3 sandwiched between the outer frame portions 11E of the lower and upper transparent electrode substrates 11a and 11b is, for example, a conductive pattern having a thickness of about 12 μm to 50 μm on a film-like insulator (base film) having a thickness of 12 μm to 50 μm. The total thickness is approximately 100 μm.
The FPC cable 3 is sandwiched through thin film transparent electrodes so as to be electrically connected to the thin film transparent electrodes on the lower and upper transparent electrode substrates 11a and 11b, and together with the lower and upper transparent electrode substrates 11a and 11b, The FPC cable 3 is joined by thermocompression bonding using ACF5 (anisotropic conductive adhesive film).

  Then, when the FPC cable 3 is bonded together with the lower and upper transparent electrode substrates 11a and 11b by ACF5 (anisotropic conductive adhesive film) by thermocompression bonding, the surface of the cover film 2 that covers the sandwiched portion of the FPC cable 3 Since a step is generated due to the influence of the thickness of the FPC cable 3, a slit 7 is provided in the upper transparent electrode substrate 11b sandwiching the FPC cable 3 as a step reducing means for reducing the step. (See FIG. 4). The slits 7 are formed along both sides in the width direction of the FPC cable 3. As a result, both ends of the upper transparent electrode substrate 11b on the FPC cable 3 cut off by the slit 7 enter along the both sides of the FPC cable 3, that is, bend into the upper transparent electrode substrate 11b outside the FPC cable 3. The FPC cable 3 is covered with a gentle slope by the cover film 2 on the slit 7.

  As described above, according to the resistive touch panel 1 of the present embodiment, the entire surface of the cover film 2 has the surface of the cover film 2 of the FPC cable 3 sandwiched on the surface of the FPC cable 3. The influence of the level difference caused by the thickness can be suppressed, and the touch panel 1 for flat surface can be provided.

The resistive film type touch panel 1 can also be configured as follows.
In other words, as shown in FIG. 5, steps for reducing the level difference in the resistive touch panel 1 are sandwiching the FPC cable 3 on the cover film 2 surface and the FPC cable 3 on the cover film 2 surface on the back surface of the cover film 2. This can be realized by the step mitigating layer 8 interposed so as to relieve the step with the entire surface other than the part.
In this case, since the FPC cable 3 and the sandwiched portion of the FPC cable 3 are thickened by the FPC cable 3 and a step is generated, a portion other than the sandwiched portion of the FPC cable 3 on the surface of the cover film 2, for example, an outside By interposing the step relief layer 8 in the frame portion 11E, it is possible to provide the resistive touch panel 1 for making a substantially flat flat surface with no step.
In addition, the level | step difference mitigation layer 8 can also be interposed in the outer frame part 11E which is a bonding location other than the clamping part of the FPC cable 3. FIG.

Moreover, as a level | step difference mitigation means in the resistive film type touch panel 1, it can also comprise as follows.
That is, in order to bond the cover film 2 to the upper surface of the upper transparent electrode substrate 11b, the step mitigating means includes a portion that causes a step, that is, the outer frame portion 11E that is a bonding portion, in addition to the sandwiched portion of the FPC cable 3. It is realizable with the adhesive 4 used excluding (refer FIG. 6). If the pressure difference is compensated by the adhesive 4, it is possible to provide the resistance film type touch panel 1 for making a substantially flat flat surface having no level difference as a whole.

DESCRIPTION OF SYMBOLS 1 Resistance film type touch panel 11 Touch panel main body 11a Lower transparent electrode substrate 11b Upper transparent electrode substrate 11E Outer frame part 2 Cover film 3 Wiring part (FPC cable)
4 Adhesive 5 ACF (Anisotropic conductive adhesive film)
6 Transparent conductive film 7 Slit 8 Step relief layer D Decoration part

Claims (5)

The first electrode substrate and the second electrode substrate each having a conductive film laminated on one surface thereof are opposed to each other with the conductive film formation surface therebetween, and the first and second electrode substrates are separated from each other by a gap. In a resistive film type touch panel, in which a wiring portion for taking out a signal is sandwiched between each conductive film in the first electrode substrate and the second electrode substrate and bonded together,
A cover film bonded to the outer surface of the first or second electrode substrate;
A resistance film type touch panel comprising: a step leveling means for relaxing a level difference caused by the thickness of the wiring portion.   2. The resistive film type touch panel according to claim 1, wherein the step relief means is a step relief slit formed in the first electrode substrate or the second electrode substrate covering the wiring portion.   The step leveling means is a step leveling layer interposed on the back surface of the cover film so as to relax the level difference between the clamping part of the wiring part and a part other than the clamping part of the wiring part. The resistive film type touch panel according to claim 1, wherein:   4. The resistive film type touch panel according to claim 3, wherein the step-relief layer is interposed at a bonding portion of the first electrode substrate and the second electrode substrate other than the sandwiching portion of the wiring portion. .   The step leveling means is an adhesive used in a portion other than the sandwiched portion of the wiring portion in order to bond the cover film to the outer surface of the first or second electrode substrate. The resistive film type touch panel according to any one of claims 1-4.

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