JP6703826B2 - Film bonding method - Google Patents

Description

The present invention relates to a film bonding method.

2. Description of the Related Art Conventionally, an image display device such as a liquid crystal display device uses a member formed by laminating a plurality of films. For example, a sensor for a touch panel is known, which is configured by laminating a sensor film having an electrode and a lead wiring connected to the electrode, and an optical film. Accurate positioning is required for bonding these films. When the films are attached to each other, an alignment mark is usually formed at a predetermined position on the film, and the alignment mark is detected to align the films. For example, when manufacturing the touch panel sensor, an alignment mark is formed on a portion other than the visible portion of the sensor film (for example, a bezel portion).

On the other hand, in recent years, image display devices have been required to have a narrow bezel. As described above, in the method of forming the alignment mark on the bezel portion and bonding the plurality of films together, the formation of the alignment mark becomes a factor that hinders the narrowing of the bezel.

JP, 2011-248207, A

The present invention has been made to solve the above conventional problems, and a main object thereof is to provide a film bonding method suitable for narrowing the bezel of an image display device.

The film laminating method of the present invention is a film laminating method for laminating a sensor film and an optical film, wherein an electrode and a lead wiring connected to the electrode are provided on at least one surface of the sensor film. It includes arranging and aligning the optical film with the lead-out wiring as a reference, and then bonding the sensor film and the optical film together.
In one embodiment, a reference line of a sensor film configured by connecting two reference points set on the routing wiring is detected, and a reference line of the optical film set on the optical film is detected. The method includes a reference line detection step, a positioning step of positioning the sensor film and the optical film, a bonding step of bonding the sensor film and the optical film, and a bonding step. Adjusting the angle formed by the reference line of the sensor film and the reference line of the optical film, and adjusting the planar view distance between the reference line of the sensor film and the reference line of the optical film.
In one embodiment, in the alignment step, after adjusting the angle formed by the reference line of the sensor film and the reference line of the optical film, the reference line of the sensor film and the reference line of the optical film are adjusted. The angle formed is −0.5° to 0.5°.
In one embodiment, in the alignment step, after adjusting the angle formed by the reference line of the sensor film and the reference line of the optical film, the reference line of the sensor film and the reference line of the optical film are adjusted. The angle formed is 89.5° to 90.5°.

According to the present invention, when the sensor film on which the routing wiring is formed and the optical film are bonded together, the optical film is aligned with reference to the routing wiring, thereby narrowing the bezel of the image display device. It is possible to provide a film bonding method suitable for the above.

It is a schematic plan view which shows an example of the sensor film used for the film bonding method by one Embodiment of this invention. (A) is a schematic plan view showing an example of reference points and reference lines set on the sensor film. FIG. 3B is a schematic plan view showing an example of reference points and reference lines set on the optical film. (A)-(c) is a figure explaining the alignment process of the film bonding method by one Embodiment of this invention. It is a schematic plan view which shows an example of the reference line set to the sensor film and the optical film. It is a schematic plan view which shows an example of the reference line set to the sensor film and the optical film. It is a schematic plan view which shows an example of the reference line set to the sensor film and the optical film.

The film bonding method of the present invention is a method of bonding a sensor film and an optical film.

A. Sensor Film FIG. 1 is a schematic plan view showing an example of a sensor film used in a film bonding method according to an embodiment of the present invention. The electrode 10 and the lead wiring 20 connected to the electrode 10 are arranged on at least one surface of the sensor film 100. Preferably, the electrode 10 and the leading wiring 20 are formed on the transparent base material 30. The sensor film 100 is suitably used as a touch sensor for a touch panel. The sensor film used for the touch sensor usually has a display area and a non-display area (specifically, an area corresponding to the bezel portion of the image display device). The electrode 10 is arranged in a region corresponding to the display region. Therefore, the electrode 10 is preferably transparent. For example, the electrode 10 is composed of a transparent conductive layer formed by patterning. The lead wiring 20 may be formed in the peripheral portion of the sensor film 100. When the sensor film 100 is used in an image display device including a touch panel, the routing wiring 20 is usually arranged in the area corresponding to the non-display area. Although not shown, a functional layer such as a hard coat layer, an optical adjustment undercoat layer, or an antiblocking layer may be provided between the transparent substrate and the electrode.

The electrode 10 can function as a touch sensor electrode that senses a touch on the touch panel.

For the electrode 10, a metal oxide film is formed on the transparent substrate 30 by any appropriate film forming method (for example, vacuum deposition method, sputtering method, CVD method, ion plating method, spray method, etc.). Can be formed. Preferably, the metal oxide film is patterned by an etching method or the like.

Examples of the metal oxide include indium oxide, tin oxide, zinc oxide, indium-tin complex oxide, tin-antimony complex oxide, zinc-aluminum complex oxide, and indium-zinc complex oxide. Among them, indium-tin composite oxide (ITO) is preferable.

Other examples of the electrode 10 include a transparent conductive layer containing a conductive filler (for example, metal nanowire), a transparent conductive layer containing a conductive resin, and the like.

The lead wiring 20 may have a function of sending an electric signal from the electrode 10 to a control unit (not shown). Usually, a plurality of the lead wirings 20 are arranged.

Any appropriate material can be used as the material forming the lead wiring 20 as long as it is a material having conductivity. For example, copper, copper alloy, conductive silver paste or the like is used.

In one embodiment, the transparent base material 30 includes a touch panel substrate part 31 and a connection part 32. The electrodes 10 and the lead wirings 20 are arranged on the touch panel substrate 31. The end portion of the lead wiring 20 is arranged on the connection portion 32. The touch panel substrate portion 31 may have any suitable shape. The touch panel substrate portion 31 has, for example, a substantially rectangular shape as illustrated. Further, the connecting portion 32 is provided so as to project from one side of the touch panel substrate portion 31. In the illustrated example, the connection portion 32 is provided on the short side of the touch panel substrate portion 31.

In one embodiment, the lead wiring 20 is provided substantially parallel to any side of the touch panel substrate portion 31 having a substantially rectangular shape. More specifically, the lead-out wiring 20 can be composed of a line segment that is substantially parallel to the long side of the touch panel substrate portion 31 and a line segment that is substantially parallel to the short side thereof, as in the illustrated example.

Any appropriate material can be used as the material forming the transparent substrate 31. Specifically, for example, polymer base materials such as films and plastics base materials are preferably used. This is because the smoothness of the transparent substrate and the wettability with the composition for forming the transparent conductive layer are excellent.

The material forming the transparent base material 30 is typically a polymer film containing a thermoplastic resin as a main component. Examples of the thermoplastic resin include polyester resins such as polyethylene terephthalate (PET); cycloolefin resins such as polynorbornene; acrylic resins; polycarbonate resins; cellulose resins. You may use the said thermoplastic resin individually or in combination of 2 or more types.

B. Optical film Examples of the optical film include a polarizing plate, a retardation plate, an isotropic film and the like.

The optical film may be a single layer or a multilayer. In one embodiment, a polarizing plate including a polarizer and a protective film arranged on at least one side of the polarizer is used as the optical film. Moreover, you may use the multilayer optical film containing a polarizing plate and another optical film (for example, retardation plate). Preferably, the optical film contains any suitable pressure-sensitive adhesive layer. In the polarizing plate, the pressure-sensitive adhesive layer may be arranged on the side of the protective film opposite to the polarizer. The sensor film and the optical film can be attached to each other via an adhesive layer. A separator may be placed outside the pressure-sensitive adhesive layer to protect the pressure-sensitive adhesive layer until the optical film is attached to the sensor film.

The size of the optical film is preferably at least a size that covers the entire area of the sensor film where the electrodes are formed. The shape of the optical film can be any suitable shape. Preferably, the optical film has a substantially rectangular shape.

C. Bonding of Sensor Film and Optical Film The bonding method of the present invention includes aligning the optical film with reference to the routing line arranged on the sensor film. According to the bonding method of the present invention, it is possible to bond the sensor film and the optical film without forming an alignment mark on the film. The region for forming the alignment mark is an unnecessary region from the viewpoint of the touch sensor function. In the present invention, such unnecessary areas can be eliminated. More specifically, conventionally, the alignment mark was formed in the non-display area, that is, the area corresponding to the bezel portion of the image display device. It is possible to narrow the bezel of the display device. Hereinafter, a typical example of the film bonding method of the present invention will be described.

C-1. Reference Line Detection Step First, the reference line of the sensor film and the reference line of the optical film are detected. The reference line is detected as, for example, a line formed by setting two or more (preferably three or more) reference points on the film, detecting the reference points, and connecting the reference points.

Preferably, each of the sensor film and the optical film is held by the alignment device and is subjected to the detection step. As the alignment device, any suitable device can be used as long as it has a function of holding the film and moving the held film in the plane direction and the vertical direction of the film. The alignment apparatus includes any appropriate control unit, and after the reference line detection step, the sensor film and/or the optical film is moved in the plane direction of the film in the alignment step described below, and in the bonding step described below, The sensor film and/or the optical film is moved in the vertical direction of the film.

FIG. 2A is a schematic plan view showing an example of reference points and reference lines set on the sensor film. The reference points 101 and 102 of the sensor film are set on the routing line 20 arranged on the sensor film 100. A line formed by connecting the reference points 101 and 102 is the reference line 110. Preferably, the angle formed by the reference line 110 and one side of the sensor film 100 is −0.5° to 0.5° (more preferably −0.3° to 0.3°, further preferably 0°). Alternatively, the reference point is set to be 89.5° to 90.5° (more preferably 89.7° to 90.3°, further preferably 90°). In one embodiment, like the illustrated example, both ends of the line segment that constitutes the routing line 20 are set as reference points 101 and 102 of the sensor film.

Normally, a plurality of routing wirings 20 are arranged, but any of the routing wirings 20 for which the reference point is set may be any routing wiring 20. Preferably, a reference point is set on the outermost routing wiring 20 or the innermost routing wiring 20 with the outer peripheral side of the sensor film as the outer side. The reference point set in such a position is easy to detect.

Detection of the reference points 21, 22 of the sensor film is typically performed using any suitable camera. For example, the sensor film is photographed with a CCD camera, and the reference point set as described above is detected from the obtained photographed image.

FIG. 2B is a schematic plan view showing an example of reference points and reference lines set on the optical film. As the reference points 201 and 202 of the optical film 200, for example, vertices on the outer circumference that define the optical film can be selected. Preferably, adjacent vertices are set as the reference points 201 and 202 as in the illustrated example. In this case, one side of the optical film 200 becomes the reference line 210.

Detection of fiducial points 201, 202 on the optical film is typically performed using any suitable camera. For example, an optical film and its periphery are photographed with a CCD camera, and the reference point set as described above is detected from the contrast difference in the obtained photographed image.

When the optical film is a polarizing plate, the reference point may not be set and the absorption axis or the transmission axis of the polarizer included in the polarizing plate may be used as the reference line.

C-2. Alignment Step FIG. 3 is a diagram illustrating the alignment step of the film bonding method according to one embodiment of the present invention. After detecting the reference line as described above, as shown in FIGS. 3A to 3C, the sensor film 100 and the optical film 200 are aligned with each other. In one embodiment, the alignment brings the two films closer together so that one film is above the other film and adjusts the angle of the reference lines of the sensor film 100 and the optical film 200, and then the reference line. It is done by adjusting the distance. In another embodiment, the alignment involves bringing the two films closer together such that one film is above the other, adjusting the distance between the reference lines of the sensor film and the optical film, and then adjusting the angle of the reference lines. Is adjusted and done. Preferably, from the viewpoint of production efficiency, as in the illustrated example, the angle of the reference line is adjusted, and then the distance of the reference line is adjusted to perform the alignment. The movement of the film due to the above-described adjustment (and film bonding described later) is performed by an alignment device holding the film.

(Reference line angle adjustment)
As shown in FIGS. 3A and 3B, the angle formed by the reference line 110 of the sensor film 100 and the reference line 210 of the optical film 200 is adjusted. Hereinafter, the angle formed by the reference line 110 of the sensor film 100 and the reference line 210 of the optical film 200 is also simply referred to as an angle A. Further, the angle A before adjustment is also referred to as an initial angle A1, and the angle A after adjustment is also referred to as an angle A2.

For the adjustment of the angle A, for example, the initial angle A1 is measured, and the sensor film 100 and/or the optical film 200 is rotated in the in-plane direction until the angle A reaches a desired angle A2 with reference to the initial angle A1. Is done. The angle A is, for example, the reference points 101 and 102 of the sensor film 100 and the reference points 201 and 202 of the optical film 200, which are imaged and coordinated on the same plane, and the equation of the reference line 110 of the sensor film 100 and the reference of the optical film. It is calculated and calculated from the equation of line 210.

In one embodiment, the angle A2 is preferably −0.5° to 0.5°, more preferably −0.3° to 0.3°, and even more preferably FIG. 3(b). Is 0° as shown in FIG. In another embodiment, the angle A2 is preferably 89.5° to 90.5°, more preferably 89.7° to 90.3°, and even more preferably 90° (Fig. 4). , FIG. 5).

(Reference line distance adjustment)
Then, as shown in FIGS. 3B and 3C, the deviation between the sensor film 100 and the optical film 200 is adjusted. The deviation is adjusted by adjusting the distance (planar view distance) between the reference line of the sensor film 100 and the reference line of the optical film 200.

The alignment between the sensor film 100 and the optical film 200 is performed by, for example, a reference line 110 of the sensor film 100 and a reference line 110 that is orthogonal to one reference point (the reference point 101 in the illustrated example) of the sensor film 100. It is performed with reference to the second reference line 120. More specifically, when the reference line 110 direction is the X direction and the second reference line 120 direction is the Y direction, the planar view distance Δx between the sensor film 100 and the optical film 200 in the X direction, and the sensor film in the Y direction. The sensor film 100 and/or the optical film 200 is moved in the X direction or the Y direction until the planar view distance Δy between the 100 and the optical film 200 reaches a desired distance. In the illustrated example, “the planar view distance Δx between the sensor film 100 and the optical film 200 in the X direction” is the second reference line 120 of the sensor film 100, the reference line 210 of the optical film 200, and the optical film 200 of 1. It is the plane view distance from the second reference line 220 of the optical film 200 orthogonal to one reference point (reference point 201 in the illustrated example). The “planar viewing distance Δy between the sensor film 100 and the optical film 200 in the Y direction” is the planar viewing distance between the reference line 110 of the sensor film 100 and the reference line 210 of the optical film 200.

C-3. Bonding Step Next, the sensor film and the optical film are bonded together. For example, when a film including a pressure-sensitive adhesive layer and a separator that protects the pressure-sensitive adhesive layer is used as the optical film, after the separator is peeled off, the sensor film and the optical film are brought close to each other to bond these films. Alternatively, the sensor film and the optical film may be bonded together while pressing the optical film 200 with the bonding roll from one end toward the other end.

2 to 3, the sensor film (strictly speaking, the touch panel substrate portion) and the optical film both have a rectangular shape, and the reference line of each film is set in the long side direction of the sensor film and the optical film. Although the example in which the adjustment is performed so as to be parallel to each other is shown, the present invention is not limited to this embodiment. Hereinafter, typical examples of the embodiment of the present invention will be shown.

A1: The reference line 110 of the sensor film 100 is set in the long side direction of the sensor film 100, the reference line 210 of the optical film 200 is set in the short side direction of the optical film, and the reference line 110 and the reference line 210 are The angle formed is adjusted to 89.5° to 90.5° (more preferably 89.7° to 90.3°, further preferably 90°) (FIG. 4).

B1: The reference line 110 of the sensor film 100 is set in the short side direction of the sensor film 100, the reference line 210 of the optical film 200 is set in the long side direction of the optical film, and the reference line 110 and the reference line 210 are The angle formed is adjusted to 89.5° to 90.5° (more preferably 89.7° to 90.3°, further preferably 90°) (FIG. 5).

B2: The reference line 110 of the sensor film 100 is set in the short side direction of the sensor film 100, the reference line 210 of the optical film 200 is set in the short side direction of the optical film, and the reference line 110 and the reference line 210 are The angle formed is adjusted to −0.5° to 0.5° (more preferably −0.3° to 0.3°, further preferably 0°) (FIG. 6).

10 Electrode 20 Lead wiring 30 Transparent substrate 100 Sensor film 101, 102 Sensor film reference point 110, 120 Sensor film reference line 200 Optical film 201, 202 Optical film reference point 210, 220 Optical film reference line

Claims (3)

A film bonding method for bonding a sensor film and an optical film, comprising:
An electrode and a lead wiring connected to the electrode are disposed on at least one surface of the sensor film,
A reference line detecting step of detecting a reference line of a sensor film configured by connecting two reference points set on the routing wiring, and detecting a reference line of the optical film set on the optical film;
A positioning step of positioning the sensor film and the optical film,
Laminating the sensor film and the optical film, a laminating step,
The alignment step is
Adjusting the angle between the reference line of the sensor film and the reference line of the optical film, and
Adjusting a planar view distance between the reference line of the sensor film and the reference line of the optical film,
Film bonding method. In the alignment step, after adjusting the angle formed by the reference line of the sensor film and the reference line of the optical film, the angle formed by the reference line of the sensor film and the reference line of the optical film is −0. The film bonding method according to claim 1 , wherein the film bonding method is 5° to 0.5°. In the alignment step, after adjusting the angle formed by the reference line of the sensor film and the reference line of the optical film, the angle formed by the reference line of the sensor film and the reference line of the optical film is 89.5. The film bonding method according to claim 1 , wherein the film bonding method is in the range of 9 to 90.5°.

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