JP4752033B2 - Touch panel and method for manufacturing touch panel - Google Patents

Description

  The present invention relates to a touch panel and a method for manufacturing the touch panel, and more particularly to a processing technique of a transparent electrode by laser patterning.

  In electronic devices such as personal digital assistants (PDAs), notebook PCs, OA devices, medical devices, and car navigation systems, touch panels for combining these displays with input means (pointing devices) are widely used. Typical touch panels include a resistance film type, an electromagnetic induction type, and the like, as well as a capacitance type (also referred to as a capacitive coupling type).

  A general electrostatic capacitance type touch panel has, for example, two transparent resin films having predetermined dielectric characteristics, each having a transparent conductive film (line electrode) laser-patterned in a stripe shape on one surface thereof. And while the said transparent resin film is made to oppose so that the said stripe-shaped transparent conductive film may orthogonally cross, it is comprised through the insulating layer between them. One side of the transparent resin film on which the transparent conductive film is not disposed is an input surface, and the input surface is disposed so as to be exposed to the outside.

  In this capacitive touch panel, a measurement voltage is alternately applied to each transparent conductive film at regular intervals by a drive circuit connected from the outside during driving. When the user presses an arbitrary position on the transparent resin film with a finger in this state, a plurality of capacitance (capacitor) structures are formed by the user's finger (grounding), the transparent resin film, and each transparent conductive film at the pressing position. The The current change of each of the plurality of capacitors is monitored, and a position where the maximum change exists is detected as an input position. Thereby, the coordinates of the contact portion on the panel are recognized, and an appropriate interface function is achieved.

  Laser patterning of the resin film with transparent electrode eliminates the need for solution and drainage management in the wet method (Patent Documents 1 and 2), as well as ablation (explosive from solids) compared to the other methods. There is an advantage that fine processing is possible by the particle release phenomenon). On the other hand, the transparent conductive film and the transparent resin film have essentially high visible light transmittance, and the laser energy absorption rate is lower than that of the non-transparent material. For this reason, it is necessary to process the transparent conductive film with a relatively high laser intensity at the time of patterning. However, the transparent resin film becomes susceptible to heat at the same time as the transparent conductive film, and the transparent resin film is damaged by heat. It may happen.

  Therefore, in recent years, a laser patterning technique using a UV laser having a wavelength of around 355 nm as a third harmonic has been developed (Patent Document 6). Since the UV laser with a wavelength of 355 nm has a low absorption rate in the transparent resin film and a high absorption rate in the conductive film, only the conductive film can be selectively laser-patterned without increasing the laser power. Further, since the light condensing property is good at a short wavelength, fine patterning is possible.

Furthermore, Patent Document 7 discloses a processing technique for selectively ablating only the intermediate layer by irradiating a third harmonic laser from the outside to a film laminate formed by laminating a plurality of resin films and a transparent conductive film. It is disclosed. According to this processing technique, there is an advantage that the laser is transmitted through a certain transparent resin film such as PET, and the laser power can be easily concentrated on the processing target surface below.
Japanese Patent Laid-Open No. 4-147526 JP-A-4-84525 JP-A-6-214705 Japanese Patent Laid-Open No. 2-259727 Japanese Patent Laid-Open No. 2001-202826 JP 2003-37314 A JP 2004-202498 A Japanese Patent Laid-Open No. 2003-23230

However, there are some problems in applying the conventional techniques such as Patent Documents 6 and 7 to the touch panel manufacturing method.
At present, along with the trend of higher definition of displays such as LCDs in the market, the touch panel mounted on the display is required to have higher precision and higher definition as well. For this purpose, it is necessary to form a transparent electrode to be laser-patterned on the transparent resin film with high definition and to align the transparent electrodes for each transparent resin film with high accuracy.

  Here, as described above, the third harmonic laser has a wavelength that does not easily affect the resin film or the like. However, when high-definition laser patterning is performed, the thermal effect cannot be sufficiently avoided at present. In addition, Patent Document 7 merely discloses a technique for processing an intermediate layer of a general film laminate, and when applied as it is to a high-definition touch panel, the optical characteristics are distorted due to the rise of the transparent conductive film in the heat-affected width. The degradation of visibility and sensing performance is expected to be a problem.

  On the other hand, when such a high-definition transparent electrode is formed on a transparent resin film, it is necessary to align each transparent electrode for each film to a higher degree than in the past. There is a risk of reducing the manufacturing efficiency of the touch panel. Therefore, sufficient measures have not yet been taken for measures for achieving compatibility with the above-described problems related to thermal effects.

As described above, there are still problems to be solved in performing fine laser patterning in the touch panel field.
The present invention has been made in view of the above problems, and has a fine transparent electrode structure with a processing width of 10 μm or less and a resin with a transparent electrode for a touch panel that has excellent visibility by suppressing thermal effects. It aims at providing the touch panel which exhibits favorable visibility and input performance by using the manufacturing method of the touch panel which can produce a film, and the resin film with a transparent electrode created by the said method.

  In order to solve the above-described problems, the present invention provides a touch panel manufacturing method that includes a processing step of patterning a transparent electrode by scanning a transparent conductive film with a UV laser, wherein the processing step is inserted into a transparent resin film. The workpiece having a transparent conductive film is irradiated with laser through the transparent resin film, and the focal beam radius in the transparent conductive film is adjusted to a condition range larger than the processing width radius. The laser intensity for ablating the transparent conductive film portion corresponding to the processing width was adjusted, and patterning was performed with a processing width of 10 μm or less.

A method for manufacturing a touch panel that undergoes a processing step of patterning a transparent electrode by scanning a transparent conductive film with a UV laser, wherein the processing step includes a transparent conductive film interposed between the workpiece and the workpiece. While irradiating the transparent conductive film with laser through the resin transparent resin film, the beam width corresponding to an intensity level 0.65 to 0.7 times the peak intensity h in the laser intensity distribution represented by a Gaussian distribution is w ₁ , and the peak intensity h is when the beam width corresponding to 0.35 to 0.4 times the intensity level and w _2, to adjust the working width ranges to be w ₁ or w ₂ below to ablate a corresponding transparent conductive film portion in the following processing width 10μm You can also

Further, in the processing step, the size ratio between the focal beam radius and the processing width radius can be adjusted by adjusting the focal length.
In the processing step, the ratio w / wo between the processing width radius w and the focal beam radius wo can be adjusted to be 0.7 or less.
Further, in the processing step, a UV laser having a wavelength of 320 nm or more and 450 nm or less can be used as the UV laser.

In the processing step, a third harmonic YAG laser can be used as the UV laser.
In the processing step, the patterning conditions are adjusted so that the ratio f ₁₂ / W of the laser focal length f ₁₂ of the processing lens optical system and the lens incident beam radius W in the laser irradiation apparatus is 40 or more and 98 or less. You can also.

  In the processing step, as a specific transparent resin film that transmits laser, polyethylene terephthalate, polyimide, polyethylene naphthalate, polyethersulfone, polyetheretherketone, polycarbonate, polypropylene, polyamide, polyacryl, acrylic, amorphous One or more of high quality polyolefin resin, cyclic polyolefin resin, aliphatic cyclic polyolefin, and norbornene thermoplastic transparent resin can be used.

On the other hand, in the processing step, as the specific transparent conductive film, antimony-added lead oxide, fluorine-added tin oxide, aluminum-added zinc oxide, potassium-added zinc oxide, silicon-added zinc oxide, zinc oxide-tin oxide system, indium tin oxide One or more of indium oxide-tin oxide, tin oxide film, copper, aluminum, nickel, and chromium can also be used.
Further, in the processing step, when using indium tin oxide for the transparent conductive film and polyethylene terephthalate film for the transparent resin film as the workpiece, the ratio of the processing width radius w to the focal beam radius wo is in the range of 1.5 to 2.3. The processing width can be adjusted to 5 μm or more and 10 μm or less, and the laser energy per pulse applied to the ITO film can be set in the range of 0.2 μJ / pulse to 1.4 μJ / pulse.

Here, as the workpiece, a pair of resin films with a transparent conductive film laminated with an insulating layer so that the transparent conductive films face each other can be used.
An adhesive layer can be used as the insulating layer.
Furthermore, the present invention is a film laminate for a touch panel formed by laminating a pair of transparent electrode-attached resin films so that the transparent electrodes on each of the films are opposed to each other at a predetermined interval. At least one of the resin films with a transparent electrode was obtained by patterning the transparent conductive film by the processing step of the present invention described above.

Furthermore, the present invention is a capacitive touch panel using a resin film with a transparent conductive film in which a transparent electrode is disposed on the main surface of the transparent resin film, wherein the resin film with a transparent electrode is the above-described present invention. The transparent conductive film was patterned by the processing step.
Further, the present invention is a capacitive touch panel comprising a film laminate in which a plurality of transparent electrodes are respectively disposed on both main surfaces of an insulating layer, wherein at least one of the main surfaces of the insulating layer The transparent electrode was patterned by the processing step according to any one of claims 11 to 12.

According to the method for manufacturing a touch panel of the present invention having the above characteristics, the following effects can be obtained.
First, according to the present invention, by using a UV laser (for example, a third harmonic YAG laser having an ultraviolet wavelength of 355 nm) during laser patterning, the laser is selectively applied only to the transparent conductive film on the transparent resin film. Energy absorption can be performed. For this reason, for example, when processing an ITO film in a PET film with an ITO film, only ITO can be selectively vaporized (ablated) without damaging the PET film.

  Secondly, the laser intensity outside the machining width is sufficiently reduced by patterning with the machining width radius w smaller than the focal beam radius wo and the laser intensity (peak value in the Gaussian distribution) weakened. For this reason, the heat affected width formed at the outer edge of the processing width is reduced. As a result, a so-called “swell” portion is unlikely to occur near the edge facing the ITO processing width. In addition to this, the continuity and linearity of the boundary line between the transparent conductive film portion to be ablated and the other film portions are maintained well, and no discoloration due to burning occurs.

  In addition, when a laser-processed resin film with a transparent electrode is used, as shown in Fig. 15 (c), the region X1 where the transparent conductive film (ITO film here) does not exist on both sides and the ITO film on both sides There is a region X2 that exists only on one side, and an intersection region X3 of the matrix-like transparent electrode groups 12b and 22b, but the electrode width and the electrode gap are formed with a width of 10 μm or less, which is below the normal human visibility limit. Even when viewed from such a watermark position, there is no actual visibility distortion on the film. As a result, an image on a high-definition LCD or the like is displayed without being damaged, and good image display performance can be exhibited.

In addition, since the thermal influence width is kept small, the optical distortion of the touch panel is suppressed, and the image display performance and visibility are not impaired when combined with a display such as an LCD.
Furthermore, in the present invention, the above effect can be obtained by using a laminate as a workpiece for laser processing. Therefore, since each transparent resin film is laminated with a transparent conductive film in advance before laser processing, as a third effect, there is no need to align each of the transparent electrodes formed by processing the transparent conductive film after laser patterning. It is. This effect is extremely useful in improving the production efficiency in a touch panel formed by laminating a resin film with a transparent electrode, and is a remarkably excellent merit in producing a high-definition touch panel. Further, since the surface to be processed is located inside the workpiece and is not exposed to the outside, there is an effect of preventing the conductive film from being damaged by handling. Moreover, since the debris generated when the transparent conductive film evaporates during the laser irradiation does not scatter, problems such as a short circuit due to the debris can be effectively suppressed.

In addition, as the definition of the transparency of the transparent conductive film in the resin film with a transparent conductive film referred to in this application, the light transmittance of the resin film itself is 100 [%] in the visible range (wavelength of about 400 nm to 800 nm or less). In this case, the average transmittance of the film is 80% or more.
In addition, the “focus beam radius” referred to in the present application is a radius of a circle having a 1 / e ² intensity of the peak value of the Gaussian distribution in the focused focused beam, and indicates a substantial laser spot radius at the focus. . Therefore, for example, even if blurring occurs near the outer edge of the laser spot due to the aberration of the condenser lens, the radius of the laser spot including the blurred region is not used as the focal beam radius, but rather refers to a radius defined by a Gaussian distribution. And

The “laser intensity” in the present application refers to an intensity comprehensively determined by laser power, laser energy, laser energy density, and the like.
In the present invention, “UV laser” refers to a laser having a wavelength of 320 nm or more and 450 nm or less.
“Ablation” in the present application means pulse laser ablation (PLA) and refers to a phenomenon in which a transparent conductive film that has received laser energy rapidly evaporates. In this application, since the surface to be processed in the transparent conductive film is sealed between the resin film and the adhesive layer, it can be a different process from the ablation in the open air type, but both are substantially the same ablation. It is believed that there is.

Each embodiment and example of the present invention will be described below, but the present invention is naturally not limited to these forms, and can be appropriately modified and implemented without departing from the technical scope of the present invention. can do.
<Embodiment 1>
(Configuration of patterning device)
FIG. 1 is a diagram showing a schematic configuration of a laser processing apparatus (laser trimming apparatus) 1 used for producing a resin film with a transparent electrode of the present invention. FIG. 2 is a functional block diagram of the apparatus.

First, as shown in FIG. 1, the apparatus 1 is a combination of an xy table 10 and a laser irradiation system 2.
On the rectangular pedestal 11, a bridge portion 12 in which inverted U-shaped angle members are combined is disposed so as to straddle the xy table 10 from above. The bridge portion 12 is provided with a machining head 100 by means such as screws.

  The xy table 10 is a feeding means for a workpiece WP (precursor film laminate) placed thereon, and includes a y-axis table 13 and an x-axis table 14 sequentially stacked on a pedestal 11. The tables 13 and 14 are each controlled by a digital control by the control device 3 using a personal computer, and ball screws 131 and 141 (141 not shown) and individual servo motors (not shown) attached to the ball screws 131 and 141, respectively. ) And can be reciprocated precisely and independently in the y-axis or x-axis directions. As a result, the x-axis table 14 is movable along the two-dimensional plane relative to the bridge portion 12.

As a size example, the dimensions of the xy table 10 can be 430 mm × 330 mm, the maximum workpiece speed 500 mm / sec, and the positioning accuracy ± 0.005 mm.
The laser irradiation system 2 includes a laser beam irradiation device 20, a beam transmission system 201, a processing head 100, and the like.
As shown in the functional block diagram of FIG. 2, the laser beam irradiation apparatus 20 includes a YAG laser oscillator 210, a third harmonic (THG) generator 211, an attenuator (attenuator) 212, and a beam expander inside a box-shaped casing. (EXP) 213 is built in, and the drive is controlled by the control device 3.

The YAG laser oscillator 210 is basically based on an output from an Nd: YAG pulse laser. Furthermore, by combining with the third harmonic generator 211, it is possible to obtain a specification example with an average output of 1 W to 6 W and a pulse repetition frequency of 15 to 300 kHz.
The third harmonic generator 211 adjusts the order of frequency to 3 for a laser having a power density of 1010 W / cm ² or more. In the first embodiment, a predetermined power density is secured using third harmonics.

The attenuator 212 serves as a means for attenuating the laser output. In the present invention, since the output of the YAG laser oscillator is attenuated to a considerable extent and used for fine laser patterning, the attenuator 212 is used for fine adjustment purposes. However, for example, when the output can be adjusted on the YAG laser oscillator side, the attenuator 212 is not necessary.
The beam expander (EXP) 213 serves to reduce the beam divergence angle and expand the beam diameter in accordance with the apertures of optical lenses A and B described later.

The beam transmission system 201 is a long body whose exterior is covered with a shielding member, and serves to guide the laser output from the laser beam irradiation apparatus 20 to the processing head 100.
The beam transmission system 201 is a combination of an optical lens, a mirror, and the like.
On the downstream side of the processing head 100, an optical system (not shown) is built in a prismatic housing for attaching to the bridge portion 12.

Inside the processing head 100, two optical lenses A and B (not shown) are housed at a predetermined interval d as a two-group zoom lens. Then, by adjusting the lens A, a gap d of the B, can be the principle of the so-called zoom lens (see below formula 1), along the z-z 'direction, to adjust the focal length f ₁₂ of the laser .
In the laser irradiation system 2 having the above configuration, the laser generated by the YAG laser oscillator 210 is introduced into the beam expander 213 through the third harmonic generator 211 and the attenuator 212 as shown in FIG. After that, the surface to be processed on the workpiece WP is irradiated through the optical lenses A and B. At this time, the x-axis table 14 is moved two-dimensionally along the xy-axis direction (the x-x ′ direction and the y-y ′ direction in FIG. 1), so that the laser is directed to the processing target surface in the workpiece WP. Irradiation can be performed while scanning, and linear ablation can be performed (see Fig. 6 (b)). Here, in the first embodiment, a specific transparent conductive film inside the workpiece WP placed on the x-axis table 14 can be selectively ablated with a fine processing width of 10 μm or less.

Note that the zoom lens is not limited to two groups, and may be configured, for example, as four groups.
(About workpiece WP)
The workpiece WP of the first embodiment has a laminate structure in which the transparent conductive film on the surface to be processed is not exposed to the outside, and is a precursor film laminate for a touch panel. The configuration can be exemplified as follows.

The workpiece WP is formed by laminating a transparent resin film (laser emission side), a transparent conductive film (laser emission side), an adhesive layer, a transparent conductive film (laser incident side), and a transparent resin film (laser incident side) in the same order. Composed. That is, each transparent conductive film is configured to be interposed in a resin film material including an adhesive layer.
As the transparent resin film material, various plastic films having a certain elasticity and transparency can be used. However, in the present invention, it is necessary to use a material that does not have a relatively high absorption rate around about 355 nm. This is because the transparent conductive film under the transparent resin film is selectively ablated at the time of laser irradiation. As the thickness of the transparent resin film, a thickness of 20 to 500 μm can be used as usual.

  Specific plastic film materials include polyethylene terephthalate (PET), polyimide (PI), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetheretherketone (PEEK), polycarbonate (PC), and polypropylene. (PP), polyamide (PA), polyacrylic (PAC), acrylic, amorphous polyolefin resin, cyclic polyolefin resin, aliphatic cyclic polyolefin, norbornene-based thermoplastic transparent resin, or laminates thereof Can be mentioned.

As the adhesive layer, a common commercial material similar to the transparent resin film can be applied. Specific materials include acrylic adhesives, silicon adhesives, and natural rubber adhesives. However, there shall be no alteration or discoloration due to absorption of the laser irradiation wavelength. As the layer thickness, a layer having a thickness of 10 to 150 μm is usually used.
The workpiece WP in the first embodiment uses an adhesive layer to insulate and laminate the transparent conductive films on the laser incident side and the outgoing side, but the adhesiveness is not essential, A transparent resin film having no properties may be used.

The resin film used for the workpiece WP is required to have transparency and elasticity. This is because, as will be described later, the ITO material on the surface to be processed is evaporated in the workpiece WP, and voids are generated at that time.
As the transparent conductive film, a general material can be used, but in the present invention, a material having a high absorption rate in the vicinity of about 355 nm is used.

  For example, ITO (Indium Tin Oxide), antimony-added lead oxide, fluorine-added tin oxide, aluminum-added zinc oxide, potassium-added zinc oxide, silicon-added zinc oxide, zinc oxide-tin oxide system, indium oxide-tin oxide For example, a transparent conductive material such as a tin oxide film, a tin oxide film, copper, aluminum, nickel, or chromium can be considered. Further, these alloys may be used, or different materials may be stacked. Only one of these may be used.

The transparent conductive film is formed on the transparent resin film according to the conditions such as the characteristics and film thickness of the transparent conductive film material, PVD methods such as sputtering, vacuum deposition, ion plating, etc., or CVD methods. Any method such as a coating method and a printing method is appropriately selected.
In the workpiece WP, a pair of transparent conductive film-attached resin films are configured such that the transparent conductive films face each other with an adhesive layer interposed therebetween, but the present invention is not limited to this configuration. For example, the structure which forms a transparent conductive film on both surfaces of an adhesion layer (or transparent resin film), respectively, and laminates | stacks a transparent resin film on each transparent conductive film separately may be sufficient. Moreover, a transparent conductive film may be formed on one surface of the adhesive layer, and the resin film with the transparent conductive film may be disposed on the other surface.

(Laser processing step)
Next, the laser processing step of the workpiece WP will be described. Here, the incident side transparent conductive film in the workpiece WP is a processing target.
In the laser processing step of the first embodiment, the processing width adjustment step and the laser intensity adjustment step can be performed sequentially as substeps shown below.

Needless to say, in the processing step, it is necessary to separately set conditions such as the material of the transparent conductive film, the thickness, the ambient temperature, the work speed by the xy table, and the laser pulse repetition frequency. In the present invention, it is preferable to set these conditions roughly in advance, and then perform a processing width adjustment step and a laser intensity adjustment step described later.
(Processing width adjustment step)
In the workpiece WP, in a condition range in which the focal beam radius w _{o of the} laser irradiated on the processing target surface on the laser incident side ITO film (hereinafter simply referred to as “processing target surface”) is larger than the processing width radius w. The focal length is adjusted so that the processing width becomes a predetermined value of 10 μm or less.

  Here, if the third harmonic of a YAG laser with a wavelength of 355 nm is used, the thermal effect on the laser incident side PET film can be reduced, and the light condensing performance is better than that of a laser with a longer wavelength. Suitable for processing. In addition, when using a PET film with an ITO film as a resin film with a transparent conductive film as a constituent element of the workpiece WP, the efficiency of the ITO film is selectively selectively utilized by utilizing the difference in absorption rate between the ITO and the PET film. There is a merit that can be processed well.

The focal beam radius w _{o at} the focal position using the processing head 100 can be adjusted by changing the lens gap d. That is, while maintaining always the processed surface immediately below the laser incident side PET film as the laser focus is positioned, by changing the lens interstitial d to adjust the focal length f _12.
Here, when the focal lengths of the lenses A and B in the processing head 100 are f ₁ and f ₂ , the focal length f ₁₂ of the combined lens by the lenses A and B is adjusted based on the known relational expression 1. (For example, “How to use optical components and points to note” by Tetsuo Sueda, Optronics, Figure 2.43).

<Relational expression 1> f ₁₂ = f ₁ f ₂ / (f ₁ + f ₂ -d)

As shown in those formulas 1, the focal length f ₁₂ When the lens A, a longer distance d B becomes longer.
On the other hand, the focal beam radius w _o can be adjusted based on the relational expression 2 between the focal length f ₁₂ and the beam divergence angle θ.

<Relational expression 2> Focus beam radius w _o = f ₁₂ θ (however, there is a relation of relational expression 4 described later with respect to θ)

Here, FIG. 3 is a graph showing the relationship between the laser intensity distribution and the beam diameter. As shown in FIG. 3 (a), the laser intensity on the surface to be processed on the workpiece WP has a Gaussian distribution. In general, the focal beam radius _wo has a Gaussian distribution as shown in FIG. 3 (b). It is defined as the focal radius when an incident beam with an intensity of 1 / e ² of the peak value from the center is collected by a condenser lens (see, for example, “Optical Recommendation” Fig. 15-6, Optronics).

In the conventional laser patterning processing, the focal beam radius w _o and the processing width radius w are in a relationship having practically the same size. This is because the ablation area is relatively large in conventional laser processing, and therefore the laser intensity is ensured as much as possible (thus, the absolute value of the peak value of the Gaussian distribution is set to be considerably larger than the processing threshold of the ablation object. This is because there was a request to secure the processing width.

On the other hand, the present invention does not require such ablation of a large area, and conversely is a technique for performing laser processing on a fine area of 10 μm or less. In this respect, the present invention performs the following specific condition setting, which is clearly different from the conventional laser processing technology.
According to the above equation 1, the focal length f ₁₂ is long the longer the lens gap d is, and focal beam radius w _o increases.

On the other hand, the shorter the lens gap d is, the focal length f ₁₂ is shortened, and the focal beam radius w _o becomes smaller.
By thus adjusting the lens interstitial d of the zoom lens, eventually it is possible to adjust the desired focal beam radius w _o.
At this time, by keeping the laser intensity constant and increasing the focal length, the focal beam radius w _o (= 1 / e ² ) is expanded, and the waveform of the Gaussian distribution becomes gentle. Further, when the laser intensity is gradually decreased, the peak value of the Gaussian distribution is lowered. At this time, if the laser intensity is considerably reduced, the Gaussian distribution peak value is higher than the processing threshold value of the transparent conductive film, but a Gaussian distribution having a peak value in the vicinity of the threshold value is formed. And in processed surface of the workpiece WP, as shown in FIG. 6 (a), the laser intensity inside the focal point the beam diameter 2w _o is the area of 1 / e ^2, the processing width appears.

Specifically, if the processing threshold of the transparent conductive film is set in a range of 35% to 40% or more and 65% to 70% or less of the peak value with respect to the peak value of the Gaussian distribution, the processing width becomes the focus. It is known to appear inside the beam. In other words, the beam width corresponding to the intensity level 0.65 to 0.7 times the peak intensity h in the Gaussian distribution of the laser intensity is w ₁ , and the beam width corresponding to the intensity level 0.35 to 0.4 times the peak intensity h is w _2. In this case, the processing width is adjusted so as to be within the condition range of w _{1 to} w ₂ in the Gaussian distribution, and the transparent conductive film portion corresponding to the processing width may be ablated.

Based on the above method, by adjusting the focal beam radius wo to be enlarged or reduced, a desired processing width can be set in the incident-side transparent conductive film sealed as an intermediate layer inside the workpiece WP.
(Laser intensity adjustment step)
Next, the laser intensity corresponding to the processing width adjusted to the predetermined value is determined. The laser intensity can basically be adjusted by the total laser energy per unit area given to the workpiece surface of the workpiece WP. Actually, it is comprehensively adjusted by a plurality of parameters such as pulse repetition frequency (Hz), pulse beam overlap ratio (%), work speed (mm / sec) and the like.

Once the processing width adjustment step is completed, the laser power is adjusted by a laser oscillator or an attenuator. Generally, when the laser intensity is lowered, the peak value of the Gaussian distribution is also lowered, and the processing width radius w is reduced. If this adjustment is performed as appropriate, the laser beam intensity sufficient for ablation processing is limited within the focal beam radius w _o centered at the position corresponding to the peak value, limited to the range of the processing width radius w smaller than w _o. I can concentrate.

Depending on the material characteristics of the workpiece WP, processing conditions, etc., it may be difficult to adjust the processing width adjustment step at a time. In this case, it is desirable to determine the final setting value of the processing width and the laser intensity by repeatedly performing the processing width adjustment step and the laser intensity adjustment step.
As a result of investigations by the inventors, when using a PET film formed with an ITO film as the resin film with a transparent electrode on the workpiece WP, in the processing width adjustment step, the processing width radius w and the focal beam radius wo It is preferable to set the ratio in the range of 1.5 to 2.3 and adjust the processing width to 5 μm or more and 10 μm or less. On the other hand, in the laser intensity adjusting step, it is desirable to set the laser energy per pulse applied to the ITO film within the range of 0.2 μJ / pulse to 1.4 μJ / pulse.

In this setting range, the optimum condition for setting the processing width to 6 μm or more and 8 μm or less is to set the laser energy in the range of 0.3 μJ / pulse or more and 0.6 μJ / pulse or less.
According to the execution of laser patterning in the first embodiment described above, when a laser having a wavelength of 355 nm is irradiated from the machining head 100 to the workpiece WP placed on the xy table 10, the laser is incident on the laser incident side PET. The laser energy is transmitted through the film and concentrated on the laser incident side ITO film below the film. The laser incident side ITO film is heated by this energy irradiation, and the ITO in the irradiated portion is rapidly evaporated in the workpiece WP.

  At this time, the laser incident side PET film is gently elastically deformed by volume expansion accompanying rapid evaporation of ITO, and a constant volume of voids is formed between the laser incident side PET film and the adhesive layer. The evaporated and evaporated ITO fills the inside of the gap, is pressed against the elastically deformed laser incident side PET film or the surface of the adhesive layer by the increase in atmospheric pressure accompanying the evaporated and evaporated, and fits into the fine recesses existing on the surface. Adsorbed as fine particles (see the shape of the adhesive layer X3 in FIG. 7B). As a result, the ITO fine particles adsorbed and scattered are disconnected from each other without maintaining a uniform film form, and are substantially interrupted by the laser patterning. The voids are reduced by cooling of the ITO fine particles over time.

In order to enhance the adsorption effect of the ITO fine particles, it is desirable that the surface of at least one of the PET film and the adhesive layer has a microporous structure. In addition, as film material, it is necessary to elastically deform when ITO is evaporated, so it is important to note that members that are less elastic than resin materials (general plate glass, etc.) may not be used because they may be damaged. .
The ITO fine particles adsorbed on the surface of the laser incident side PET film or the adhesive layer can be actually confirmed by elemental mapping of elemental analysis (for example, qualitative analysis SEM-EDX).

In such a series of laser patterning, the following effects are exhibited in the first embodiment.
First, even when the precursor film laminate is made a workpiece WP by irradiating and scanning a third harmonic YAG laser having an ultraviolet wavelength of 355 nm, the laser incident side and emission side PET films Only the laser incident side ITO film, which is the lower layer of the laser incident side PET film, can be selectively ablated without substantial damage (FIG. 6 (b)). Specifically, the photon energy of a YAG-THG laser (355 nm) is 80 kcal / mol, whereas the decomposition energy of CC bond is 84 kcal / mol. For this reason, even if the film material supporting the transparent conductive film is an organic material containing a carbon component such as PET, the laser energy does not decompose, so that it is not substantially thermally damaged.

Here, “substantially no thermal damage” refers to the extent that the thermal effect is so small that thermal damage of the film cannot be confirmed with the naked eye.
Further, as shown in the graph of FIG. 4, there is a clear difference between the PET film and the ITO film in the absorptance with respect to the 355 nm UV laser. As a result, if the workpiece WP is irradiated with a 355 nm UV laser, the laser can be absorbed relatively by the ITO film while transmitting the laser through the PET film. The ITO film can be selectively ablated.

Here, according to the study by the present inventors, even if another material such as a hard coat layer is provided between the ITO film and the PET film, as shown in the graph of FIG. I know I can ablate. In this case, it is assumed that the separate material is transparent to a 355 nm UV laser.
As a second effect, the processing width radius w is reduced with respect to the focal beam radius w _o and patterning is performed with the laser intensity weakened, so that the laser intensity near the hem of the Gaussian distribution becomes the processing threshold at the processing width radius w. Compared to low enough. Therefore, even if the jet of the ITO material to be ablated reaches the ITO material near the processing width, the melt width of the jet and the ITO material is not so large as compared with the case of the conventional laser intensity, so that it is substantially raised. The resulting heat affected width is kept small. This effect can also be obtained satisfactorily in the first embodiment in which the workpiece WP is ablated in a closed system.

For this reason, when using the resin film with a transparent electrode produced by laser patterning of the present invention for a touch panel, physical and optical distortion hardly occurs when laminated with other constituent films, and good visibility is ensured. The
Furthermore, by patterning under the above conditions, the excess laser intensity is reduced, so that the transparent conductive film melted during ablation is burned out, and the boundary between the processed part and the ablated part is unclear and not linear but jagged. And the problem that the film near the boundary turns black is also avoided. In the present invention, excellent visibility is also exhibited by such an action.

  In the workpiece WP, there are a total of two ITO films on the laser incident side and the laser emitting side, but the processing target surface to be ablated in the first embodiment is set with respect to the laser incident side ITO film. The The energy of the laser beam incident on the workpiece WP is consumed for the ablation of the ITO film on the laser incident side, and the energy of the laser beam incident on the ITO film on the laser emission side falls below the ablation threshold, so that the laser is emitted during laser patterning. Unnecessary patterning is not performed even if the side ITO film hits the laser. When processing both the ITO film on the laser incident side and the laser emitting side, the workpiece WP may be turned over and set on the xy table 10 sequentially. Alternatively, by devising the optical system, each ITO film can be individually irradiated with a laser.

  As a third effect, since the precursor film laminate can be used as the workpiece WP in Embodiment 1, two sheets of resin films with a transparent conductive film obtained by laser patterning as in the past are prepared. Thus, the step of pasting them together in a predetermined positional relationship is unnecessary. This effect is extremely useful for improving the manufacturing efficiency in a touch panel formed by laminating a film with a transparent electrode, and is also an excellent merit for producing a high-definition touch panel. In addition, since the surface to be processed is located in the inner layer of the workpiece WP and is not exposed to the outside, there is an effect of preventing the transparent conductive film from being damaged by handling.

Furthermore, since debris (fine dust) generated when the transparent conductive film evaporates during laser irradiation, problems such as a short circuit due to the debris can be effectively suppressed.
[Experimental examples and selection of optimum conditions]
Hereinafter, various experiments were conducted in order to investigate the optimum setting conditions at the time of carrying out the laser patterning processing of the present invention.
(Experiment 1: Experiment to confirm superiority of third harmonic (wavelength 355 nm) laser)
First, the relationship between the laser wavelength and the processing characteristics of the film and the optimum laser wavelength for patterning were investigated.

Specifically, assuming the most practical Q-switched LD-pumped Nd: YAG laser, lasers of three wavelengths (Comparative Example 1; 1064 nm, Comparative Example 2; 532 nm, Comparative Example 3; various lasers of 355 nm) Was used for patterning experiments with a processing width of 9 to 10 μm. Conventionally, since the focal beam diameter Do and the processing width are almost equal, the optical system is set so that the focal beam diameter Do is 10 μm or less.
As in the first embodiment, a film laminate (transparent resin film (beam emitting side), transparent conductive film (beam emitting side), adhesive layer, transparent conductive film (laser incident side), transparent resin film (workpiece WP) The laser incident side) is laminated in the same order. The processing target was a transparent conductive film on the laser incident side.

The implementation conditions at this time are as follows.
The diameter of the incident beam with respect to the processing lens was a constant value (5 mm) for all three wavelengths.
Comparative Example 1; wavelength 1064 nm, focal length of processing lens f ₁₂ = 35 mm, focal beam diameter D ₀ 9.5 = μm
Comparative Example 2; wavelength 532 nm, focal length f _{12 of} processing lens = 70 mm, focal beam diameter D _o 9.5 = μm
Comparative Example 3; wavelength 355 nm, focal length f _{12 of} processing lens = 100 mm, focal beam diameter D _o 9 = μm
<< Experimental result >>
In Comparative Example 1 (wavelength 1064 nm), removal processing with a processing width of 9 to 10 μm was possible when the processing target surface was at the focal position. However, the processing width became narrow only by changing the processing target surface by about 40 μm in the vertical direction. This is because the beam diameter on the surface to be processed has increased due to the fact that the surface to be processed deviates from the focal position. In the condition setting of Comparative Example 1, there is a difference in the finish of the surface to be processed due to slight condition fluctuations. There is a possibility.

On the other hand, it was confirmed that the transparent conductive film could be removed even in the conditions of Comparative Example 2 within a processing width of 9 μm or more and 10 μm or less.
However, when a processing width of 10 μm or less was formed in Comparative Examples 1 and 2, a phenomenon was observed in which both the laser incident side and laser emission side PET films near the processing width were partially melted and deformed. In References 1 and 2, the amount of energy absorbed by the PET film is high, and it is considered that the PET film on both the laser incident side and the laser emission side is affected by heat simultaneously with the processing of the transparent conductive film.

In addition, including Comparative Examples 1 and 2, the allowable variation of the machining target surface with respect to the vertical direction of a general machining system is about ± 100 μm. Therefore, in these cases, an effective removal process with a machining width of less than 10 μm cannot be performed unless the variation compensation function for the machining target surface is used.
In contrast, in Comparative Example 3 (wavelength 355 nm), the processing width hardly changed even when the processing target surface fluctuated 100 μm in the vertical direction. Also, no melt deformation of the PET film near the processing width was confirmed in Comparative Example 3.

Therefore, based on the conditions of Comparative Example 3, it was confirmed that only the transparent conductive film could be thin-line processed without substantially thermally damaging the laser incident side and laser emission side PET films.
The condition of Comparative Example 3 (wavelength 355 nm) is effective for removal processing with a processing width of less than 10 μm.
Here, FIG. 5 is a diagram showing the results of measuring the spectral transmittance of the transparent conductive film and the film substrate. This figure shows the spectral transmittance of a PET film, a PET film provided with a hard coat (HC) layer, and a film with a conductive film in which a hard coat layer and an ITO film are sequentially laminated on the PET surface.

  As is clear from this figure, Comparative Example 3 (wavelength 355 nm) has a larger amount of beam absorption in the transparent conductive material than Comparative Example 1 (wavelength 1064 nm) and Comparative Example 2 (wavelength 532 nm). The amount of beam absorption at is small. Due to the difference in the amount of beam absorption, in Comparative Example 3, it is possible to remove only the transparent conductive film with a processing width of 9 to 10 μm without melting and deforming the laser incident side and laser emission side PET films.

However, as a result of observing the thermal effect width of the transparent conductive film around the removal process, it was revealed that the heat affected width of each of Comparative Examples 1 to 3 was 2.5 μm or more, and a uniform processing target surface could not be formed. That is, in Comparative Example 3, thermal damage to the laser incident side and laser emitting side PET films can be prevented, but the thermal influence width of the transparent conductive film cannot be suppressed.
In order to use it for touch panels related to high-precision image display, it is said that the allowable thermal influence width needs to be suppressed to about 1.5 μm, and it is necessary to further solve this problem based on Comparative Example 3. I understood.
(Experiment 2: Confirmation experiment on the relationship between energy distribution and thermal influence width and thermal damage of the film caused by laser processing)
Next, in order to find a condition that allows removal processing with a processing width of less than 10 μm and that allows the heat affected width of the transparent conductive film to be an allowable width of 1.5 μm or less, based on the comparative example 3, the pulse energy and the processing width The relationship and the relationship between machining width and heat affected width were investigated.

The experimental conditions were as follows.
Example 1; wavelength 355 nm, diameter of incident beam to processing lens 5 mm, processing lens focal length f12 = 100 mm, focal beam diameter D0 = 9 μm
The experimental results are shown in FIG. 8 (relationship between pulse energy and machining width) and FIG. 9 (relationship between machining width and heat-affected width).

  As shown in FIG. 8, when the focal beam diameter Do is 9 μm, the pulse energy (μJ) is 0.8. However, by controlling the processing width as shown in FIG. 9, the heat affected width can be changed. The relationship between the pulse energy and the machining width exhibits linearity as shown in FIG. 9, and can be sufficiently controlled. According to the curve, it is confirmed that the machining width and the pulse energy are in a proportional relationship.

  On the other hand, as shown in FIG. 9, in the region (4 to 6 μm) where the processing width is small, it is confirmed that the heat affected width of the transparent conductive film is substantially constant in the vicinity of 0.9 μm. Then, as the processing width increases from 6 μm, the heat affected width gradually increases. In this figure, for example, when the processing width is 7.5 μm, the heat affected width is about 1.5 μm. This phenomenon is because the melt width of ITO (the width of the removal process strength threshold and the melt strength threshold) is small in the region where the processing width is small and is kept substantially constant, and the melt width of ITO is large in the region where the processing width is large. Conceivable.

Therefore, in order to reduce the heat affected width, it is effective to increase the gradient (see FIG. 3A) in the Gaussian distribution of the laser intensity near the edge of the processing width (removal processing intensity threshold).
According to the present invention, it has been clarified by another experiment that the thermal influence width can be reduced by setting the vicinity of the edge of the processing width to a position where the beam intensity gradient is large and 80% or less of the 1 / e ² intensity diameter. In this experimental result, the heat affected width was 1.35 μm when the processing width was 80% (7.2 μm) of the focal beam diameter Do (1 / e ² intensity diameter).

Here, the result of observing damage to the transparent conductive film on the laser emission side after laser patterning with a predetermined processing width is shown.
When the processing width was 6.5 μm or more, obvious damage was observed in the transparent conductive film on the laser emission side, but when the processing width was 6.0 μm, the damage was small enough to be seen. On the other hand, no damage was observed at a machining width of 5.5 μm or less.

Then, when a similar experiment was performed for a processing width of 5.75 μm, which is an intermediate between processing widths of 5.5 μm and 6.0 μm, no thermal damage was observed in the transparent conductive film on the laser emission side.
From the above results, in order to reduce the thermal influence width of the transparent conductive film on the laser incident side to 1.5 μm or less without substantially thermally damaging the transparent conductive film on the laser emission side, the processing width is reduced to the focal beam diameter Do. It is considered to be effective to make it 65% or less.

  In another experiment conducted by the present inventors, it has been clarified that the machining width change amount and the pulse energy change amount increase as the machining width with respect to the focal beam diameter Do decreases. That is, if the focal beam diameter Do is too small, the laser patterning may be adversely affected. Considering the stability of removal processing, the processing width is most appropriate and effective when the processing width is 45% or more of the focal beam diameter Do.

Therefore, in order to perform removal processing with a processing width of less than 10 μm, the processing width should be set to a range of 45% or more of the focal beam diameter Do. In other words, if the focal beam diameter Do at the focal point of the surface to be processed is less than 22.2 μm, a processing width of less than 10 μm can be realized.
(Experiment 3: Confirmation experiment on the relationship between the variation of the machining target surface and the machining width)
Next, in consideration of actual machining variations, the surface to be processed at a constant pulse energy is used to determine the conditions of the condensing optical system that can perform stable processing even if the surface to be processed fluctuates about ± 100 μm from the focal position. The relationship between the beam diameter D and the processing width was investigated. The experimental conditions were as follows.

<Experiment 3-1>
Example 2; wavelength 355 nm, diameter of incident beam to processing lens 5 mm, processing lens focal length f ₁₂ = 100 mm, focus beam diameter Do = 9 μm, processing width at focus position 5.4 μm (focus beam diameter Do 60) %).
In the experiment, the beam diameter D of the processing target surface was changed by shifting the processing target surface in the vertical direction from the focal position.

The results of this implementation are shown in FIG.
As shown in this figure, it was confirmed that the processing width decreased as the beam diameter D of the processing target surface increased.
When the beam overlap ratio during actual machining is a practical value of 50%, the machining width reduction allowable value is about 80%. When the beam diameter ratio (D / Do) increases by 1.12 times, the processing width decreases to 80%. In order to perform stable machining even if the machining target surface fluctuates ± 100 μm from the focal length f _{12 in the} vertical direction (ie, the machining width is within 80%), the fluctuation of the beam diameter D of the machining target surface is 1.12 times or less. Must be kept to a minimum.

Here, the focusing characteristic of the Gaussian beam near the focal point is z, where the distance from the focal point is z.
<Relational expression 3> w ² = w _o ² [1+ (λz / πw ₀ ² ) ² ]
It is represented by
Further, the focal beam radius w _o is expressed by the relational expression 2,
Furthermore, the beam divergence angle θ is <Relational expression 4> θ = λ / πW (W: incident beam radius)
It is represented by

According to the application of the above relational expressions 2 to 4, the optimum beam diameter Do (2 w _o ) of the processing optical system when the wavelength λ = 0.355 μm, z = 100 μm, and w / w _o ≦ 1.12 is satisfied. ,
9.47μm ≦ 2w _o ≦ 16.7μm
It becomes.
Also, (focal length f ₁₂ / incident beam radius W) is
41.9 ≤ f ₁₂ / W ≤ 63.3
It becomes.

<Experiment 3-2>
Example 3 As a difference from Example 2, the processing width at the focal position was set to 5.9 μm (65% of the focal beam diameter Do).
The results of this implementation are shown in FIG.
As shown in this figure, it was confirmed that the machining width decreased to 80% when the beam diameter ratio (D / Do) increased 1.14 times.

Further, according to the above relational expressions 2 to 4, the optimum focal beam diameter Do (2w _o ) when the wavelength λ = 0.355 μm, z = 100 μm, and w / w _o ≦ 1.25 is satisfied.
9.09μm ≦ 2w _o ≦ 15.4μm
It becomes. Also, (focal length f ₁₂ / incident beam radius W) is
40.2 ≤ f ₁₂ / W ≤ 68.1.

<Experiment 3-3>
Example 4 As a difference from Example 2, the processing width at the focal position was 4.1 μm (45% of the focal beam diameter Do).
Then, the beam diameter D of the processing target surface where the processing width decreases to 3.2 μm (80%) was obtained while shifting the processing target surface from the focal position. The results of this implementation are shown in FIG.

As shown in this figure, the beam diameter D when the processing width was reduced to 80% (3.2 μm) was approximately 9.4 μm (w / w _o = 1.04).
Further, according to the above relational expressions 2 to 4, the optimum focal beam diameter Do (2 w _o ) when satisfying the wavelength λ = 0.355 μm, z = 100 μm, w / w _o ≦ 1.04 is 12.6 μm ≦ 2w _o ≦ 22.2 μm, (focal length f ₁₂ / incident beam radius W) is 55.7 ≦ f ₁₂ /W≦98.2.

From the above experiments 3-1 to 3-3, the optimum condition (focal length f ₁₂ / incident beam radius W) of the condensing optical system capable of stable processing even when the surface to be processed fluctuates about ± 100 μm is 40.2 ≦ It can be said that f ₁₂ /W≦98.2.
(Experiment 4)
Next, an experimental workpiece having a laminate structure in which a protective film (PET film), an ITO film, and an adhesive film are sequentially laminated is prepared, and the ITO film is laser patterned from the protective film side with a processing width of 10 μm or less (electrical In the case of changing the resistance characteristics), the processing conditions under which the protective film and the adhesive film are not substantially affected by heat were investigated. FIG. 7 (a) is a partial cross-sectional view showing a state before laser processing, and FIG. 7 (b) is a state after laser patterning. X1, X2, and X3 represent a PET film, an ITO film, and an adhesive layer, respectively.

For the adhesive film, a material used when actually manufacturing a touch panel with a PET film with an ITO film was selected. The laser wavelength was set to two types, 355 nm and 532 nm.
The experimental method oscillates a laser beam with a predetermined output and repetition frequency, linearly processes an experimental workpiece placed on an xy table at a predetermined workpiece speed, and the electrical resistance of the ITO film positioned at both ends of the adhesive film. Was measured to confirm the presence or absence of modification of the ITO film, which is the intermediate layer of the experimental workpiece.

Further, the surface state, the processing width, and the processing depth after laser patterning were confirmed using a high magnification CCD camera and a confocal microscope.
As a result, as shown in FIG. 7 (b), the ITO portion subjected to laser irradiation rapidly evaporates and vaporizes between the ITO film X2 and the adhesive layer X3, as shown in FIG. 7 (b). It was confirmed that as the internal pressure increased, the adhesive layer X3 was deformed into a curved shape, and the gap X4 was formed. It is understood that the evaporated and evaporated ITO fine particles are dispersed and adsorbed in the concave portions of the curved adhesive layer surface X5.

  Here, the width of the gap X4 is 10 μm or less, and its expansion height is several μm, which is very fine, so that no substantial effect was observed even when observed with the naked eye from the outside. In addition, a plurality of bubbles X6 are generated in the adhesive layer X3 due to heat from laser irradiation, but when the adhesive layer X3 is observed using a confocal microscope, there is no substantial thermal damage and it is substantially transparent. It turned out that it did not reach the level where the sex was impaired.

  The experimental work piece has a configuration in which the adhesive layer X3 is curved and the ITO fine particles are adsorbed on the surface thereof, but when the experimental work piece is turned over, the ITO film is irradiated with laser from the PET film side. It was confirmed that the PE film was curved and almost the same result was obtained. That is, the same result can be obtained even if another resin film such as PET having a predetermined elasticity is used instead of the adhesive layer X3.

The size of the gap X3 is not limited, but in order to keep the ITO fine particles on the surface X5 of the adhesive layer X3 satisfactorily, it is preferable to have a size that can ensure a certain area of the surface X5.
In order to bend the adhesive layer or the resin film smoothly, it is understood that one having elasticity that can be bent should be selected as the internal pressure increases due to evaporation of the ITO film.
From the above observation, according to the laser patterning of the present invention, it is expected that good and fine patterning of the transparent electrode can be realized without impairing the visibility, and excellent effects can be exhibited in the touch panel manufacturing scene.

<Embodiment 2>
(Configuration of capacitive touch panel)
FIG. 13 is a set diagram illustrating a configuration example of the capacitive touch panel 4 (hereinafter referred to as “touch panel 4”) according to the second embodiment of the present invention.
As shown in FIG. 13, the touch panel 4 includes a polarizing plate 43, an adhesive layer 442, a first resin film with a transparent electrode 401, an adhesive layer 443, and a second resin film with a transparent electrode 402 in order from the top to the bottom of the paper. The adhesive layer 444, the support 451, and the adhesive layer 445 are laminated.

  The touch panel 4 includes an LCD main body 433 (a unit in which a transparent conductive layer, a color filter, a liquid crystal molecular layer, a TFT substrate, and a transparent conductive layer are stacked), which is a component of the LCD device when used. A body-type touch panel device is configured. Here, the touch panel device is assumed to be used in a car navigation system as in-vehicle use.

Needless to say, the touch panel device can be used for various purposes other than the above. For example, application to a display with a high-definition touch panel (liquid crystal display integrated touch panel device), which is assumed to be used in a notebook computer, a mobile phone, a portable information terminal device, a car navigation system, or the like is assumed.
The polarizing plate 43 is made of, for example, a linear polarizing plate having a thickness of 0.2 mm, and is adhered to the entire surface of the transparent resin film 411 in the first resin film with a transparent electrode 401 via the adhesive layer 442 and is externally provided. It is supposed to be exposed. The polarizing plate 43 suppresses the amount of reflected light caused by visible light incident on the inside of the touch panel to about half or less compared to the case where the polarizing plate is not provided. In addition, the arrangement structure (sensing pattern) of the transparent electrode groups 12b and 22b is less visible from the outside, and also serves to improve visibility.

In order to improve the visibility using the polarizing plate 43, a light isotropic substrate or a phase difference substrate is used as the transparent resin films 411 and 421. In addition, although there is actually a touch panel having a configuration in which a polarizing plate is not stacked for reasons such as cost reduction, a low-cost film substrate can be used for the transparent resin films 411 and 421 in that case.
The first and second transparent electrode-equipped resin films 401 and 402 are main components of the touch panel, and are transparent resin films (herein, PET) having a known capacitance so that sensing can be performed when the touch panel is driven. Transparent electrode groups 12b and 22b made of a material having a known resistance value (surface resistance) (here ITO) are formed on one main surface of the films 411 and 421.

The first and second resin films with transparent electrodes 401 and 402 are arranged so that the transparent electrode groups 12b and 22b face each other, and are laminated with an adhesive layer 443 interposed therebetween to form a film laminate 400. Has been.
Here, on the surface of the transparent resin films 411 and 421, it is preferable to dispose an acrylic resin coat layer as a countermeasure for preventing oligomer generation during heating such as patterning. Further, when a pen or a finger may come into contact with the surface, it is desirable to provide a hard coat film or the like in order to improve transparency, scratch resistance, wear resistance, non-glare property, and the like.

Further, before forming the transparent electrode groups 12b and 22b, an undercoat layer may be provided on the surface of the transparent resin films 411 and 421 for improving the transparency and adhesion.
Here, although the transparent conductive film material that can be used for the film with a transparent electrode film of the present invention has been described in Embodiment 1, the material of the transparent electrode groups 12b and 22b of the touch panel in Embodiment 2 is small in size. In consideration of application to electronic devices and the like, those having a low resistance value are preferable.

The transparent electrode groups 12b and 22b act as sensor traces of the touch panel 4, and are arranged in stripes on the main surfaces of the transparent resin films 411 and 421 facing each other through the adhesive layer 443 as shown in FIG. And a plurality of strip electrodes (line electrodes 12a1 to 12an, 22a1 to 22an).
The line electrodes 12a1 to 12an and 22a1 to 22an are processed into very fine stripes by laser patterning unique to the present application. By arranging the extending directions of the electrodes so as to be orthogonal to each other with the adhesive layer 443 interposed therebetween, an orthogonal matrix is formed by the line electrodes 12a1 to 12an and 22a1 to 22an. Such an electrode structure is patterned with a fine processing width of 10 μm or less by the laser processing apparatus 1 exemplified in the first embodiment of the present invention. Naturally patterning is not limited to a stripe shape, it is possible to set even in advance of any shape in the laser processing apparatus 1.

Here, as an example, the widths of the line electrodes 12a1 to 12an and 22a1 to 22an can be set to a minimum width of 300 μm and a maximum width of 4458 μm. On the other hand, the minimum gap between the adjacent electrode gaps of the line electrodes 12a1 to 12an and 22a1 to 22an can be set to 700 μm.
Each line electrode 12a1 to 12an and 22a1 to 22an is connected to a lead circuit (not shown) for supplying external power to the line electrodes. The lead circuit also uses the transparent conductive material, and a transparent resin film 411, Each surface of 421 can be provided with predetermined patterning. A known dedicated controller for applying a measurement voltage to each of the line electrodes 12a1 to 12an and 22a1 to 22an and detecting a voltage change at the time of input by the user is connected via the lead circuit.

As the transparent electrode groups 12b and 22b of the touch panel, an undercoat layer for improving a certain degree of transparency may be provided. The undercoat layer is composed of two layers having different optical refractive indexes. Of these, the low refractive index layer is disposed so as to be closer to the transparent electrode groups 12b and 22b than the high refractive index layer.
In the configuration example of FIG. 13, the transparent electrode groups 12b and 22b are disposed on one side of the transparent resin films 411 and 421. However, the present invention is not limited to this configuration. For example, one transparent film The transparent electrode group 12b may be disposed on one surface of the resin film with electrode (optical isotropic substrate), and the transparent electrode group 22b may be disposed on the other surface. However, in this case, it is necessary to pay attention to the handling of the substrate in the film forming step and the processing step so as not to damage the transparent electrode groups 12b and 22b.

Here, the adhesive layers 442, 444, and 445 are made of a transparent insulating material or a transparent adhesive, and are arranged so as to form an insulating layer on which the upper and lower layers are adhered. In addition to the adhesive layers 442, 444, and 445, a separate film or the like may be used as the base material for the insulating layer.
The support body 451 is for imparting the rigidity of the touch panel 4, and can be made of a glass plate having a thickness of 0.2 mm or more and 0.5 mm or less, or a resin material having hardness equivalent to this. The support 451 can exhibit good rigidity by being stuck on the entire surface with the adhesive layers 444 and 445. If the rigidity of the touch panel 4 does not matter so much, the support 451 can be omitted.

Next, the input detection principle (capacitance type) of the touch panel 4 having the above configuration will be described. FIG. 14 is a schematic diagram showing the principle of input detection.
At the time of driving, the dedicated controller passes through the lead-out circuit to the line electrodes 12a1 to 12an stretched in the x direction and the line electrodes 22a1 to 22an stretched in the y-direction for a predetermined time. A measurement voltage is applied alternately every xy.

  When the user touches the polarizing plate 3 in this state, as shown in FIG. 13, the user's finger, the transparent resin films 411 and 421 (and the polarizing plate 43 and the adhesive layer 442 are also included here), the line electrodes 12a1 to 12an In the meantime, a plurality of capacitors (capacitors) are formed corresponding to the number of the line electrodes 12a1 to 12an. In FIG. 14, capacitors C1 to C5 formed by line electrodes 12a1 to 12a5 are schematically shown for ease of explanation.

In this figure, capacitors C1 to C5 formed when a measurement voltage is applied between the line electrodes 12a1 to 12an extended in the x direction are shown, but the line electrodes 22a1 to 22a1 extended in the y direction are shown. When a measurement voltage is applied to 22an, a plurality of capacitors are formed according to the same principle.
Such capacitors have different capacities according to the distance between the finger position and each line electrode, and the place where the distance is the smallest is the place where the measurement voltage has the maximum amplitude. Accordingly, in the case of FIG. 14, that is, when the measurement voltage is applied between the line electrodes 12a1 to 12an, the dedicated controller specifies the place where the change in the measurement voltage is maximized, thereby Specify coordinates.

Next, in the same process as described above, the measurement voltage is applied to the line electrodes 22a1 to 22an extended in the y direction, and the line where the maximum value of the measurement voltage at that time is detected is specified, so that x Specify the direction coordinates.
Input detection is performed by the above process. In the touch panel 4, such detection steps are alternately repeated, so that input information from the user is sequentially acquired and a function as a GUI (Graphical User Interface) is exhibited.
(About features of the second embodiment)
The touch panel 4 according to the second embodiment is manufactured by forming the film laminate 400 in which the transparent resin films 401 and 402 with conductive films are disposed on both main surfaces of the adhesive layer 443 at the time of manufacture. It is characterized in that the transparent electrode groups 12b and 22b are patterned by sequentially ablating the transparent conductive film sealed under the transparent resin film 411 or 421 by irradiating laser to 400 from the outside.

By performing this laser patterning, after preparing the resin films with transparent electrodes one by one as in the past, the process of laminating them through the adhesive layer and the alignment adjustment at the time of laminating are unnecessary, and the touch panel has excellent Manufacturing efficiency is realized.
That is, conventionally, a predetermined laser irradiation is performed on a belt-shaped resin film with a transparent conductive film by a so-called step method or roll to roll method, and the transparent conductive film is continuously laser-patterned. In the touch panel manufacturing method using this conventional method, a step of cutting a resin film into a predetermined size, arranging a wiring area and a lead electrode, and then placing a pair of resin films with transparent electrodes facing each other is essential. At this time, in order to make a matrix arrangement of transparent electrodes, it is required to align the transparent electrodes of both films with very high accuracy, but the alignment must be done carefully to obtain appropriate touch panel characteristics. However, there is a limit to the transparent electrodes having a fine pattern in recent years. In addition, there is a possibility that damage may occur due to mishandling of the transparent conductive film at the time of cutting, and target patterning may become impossible. Such damage to the transparent conductive film is particularly problematic when the film with the transparent conductive film is wound into a roll.

  Therefore, according to the laser patterning method of the present invention, since the transparent conductive film formed on each of the transparent resin films 411 and 421 is integrally aligned with the adhesive layer 433 in advance in the film laminate 400, the transparent electrode For the alignment, only adjustment during laser patterning needs to be considered. As a result, the condition management can be greatly simplified and rationalized. Therefore, even if fine laser patterning is performed, processing can be performed with significantly higher precision than in the past.

Further, in the film laminate 400, since the transparent conductive film to be processed is not exposed to the outside, damage due to handling mistakes during manufacturing can be effectively reduced. Furthermore, since debris and the like generated when the transparent conductive film evaporates in laser patterning does not scatter, problems such as reattachment of evaporated ITO fine particles can be avoided.
(Method for producing film laminate)
FIG. 15 is a diagram showing a process of forming a film laminate 400 by sequentially patterning each transparent conductive film of the precursor film laminate to form a transparent electrode. 15 (a) is a front view of the resin film 401 with the first transparent electrode, FIG. 15 (b) is a front view of the resin film 402 with the second transparent electrode, and FIG. 15 (c) is an arrangement relationship between the transparent electrodes. FIG. In FIG. 15, the transparent conductive film to be ablated in the precursor film laminate is illustrated for explanation.

A precursor film laminate is prepared in advance for laser patterning.
As an example of producing a film laminate (precursor), first, a resin film with a transparent conductive film (PET film with an ITO film) is prepared. Any known method may be used as the method for forming the ITO film, but here, a sputtering method that is inexpensive and relatively easy to manufacture is suitable. A wiring area and a lead-out electrode are further provided on the film surface in accordance with a predetermined procedure.

The pair of resin films with a transparent conductive film are bonded together with an adhesive layer 433 so that the transparent conductive films face each other.
The precursor film laminate is thus obtained. In addition, you may make it provide a film separately for the polarization adjustment use etc. on the outer side of a resin film.
Subsequently, the prepared precursor film laminate is placed as a workpiece WP on an xy table of a laser processing apparatus, and laser patterning is performed.

First, in order to form the line electrodes 12a1 to 12an (transparent electrode group 12b) from the ITO film on the incident side, a pulse laser is applied to the precursor film laminate based on the adjustment conditions of the first embodiment. The pulse laser irradiates the ITO film as a ruled line, forms a processing width, and cuts the ITO on the processing target surface into a thin line shape. (Figure 15 (a)).
When all the line electrodes 12a1 to 12an are produced, the precursor film laminate is turned over and placed on the xy table again. Then, in the same manner as described above, a pulse laser is irradiated from the other ITO film to form line electrodes 22a1 to 22an (FIG. 15 (b)).

The film laminate 400 is completed by the laser patterning described above. Although not confirmed with the naked eye in the film laminate 400, typically, as shown in FIG. 15 (c), the first and second transparent electrode-attached resin films 401 and 402 are arranged so as to form a matrix with each other. ing.
In the touch panel, when viewed from the main surface direction in this way, the region X1 in which neither of the transparent electrode groups 12b and 22b exists, the region X2 in which only one of the transparent electrode groups 12b and 22b exists, and the transparent electrode group 12b , 22b is present. However, in the touch panel of the second embodiment, the line electrodes 22a1 to 22an and the electrode gap are formed with a fine width of 10 μm or less, which is lower than the normal human visibility limit. When viewed, the possibility of problems in visibility is very small. As a result, an image on a high-definition LCD or the like is displayed without being damaged, and a good image display performance can be exhibited.

In the first and second resin films with transparent electrodes 401 and 402, when an extraction electrode or the like is provided in an area other than the image display portion around the film, the extraction electrode or the like may be subjected to laser patterning according to the present invention. A known wide laser patterning may be performed.
Further, regarding patterning of so-called extraction electrodes and the like, they can be arranged by various etchings without using a laser. Since the lead-out electrodes are arranged in the wiring area, it is necessary to configure them with a conductive material having a resistance value lower than that of the transparent electrode groups 12b and 22b. Further, the low resistance wiring may be configured by using a metal paste such as gold, silver, or copper. In practice, it is preferable to use a silver paste from the viewpoint of cost and performance.

In addition, any known method such as screen printing, gravure printing, or mask printing may be used as a configuration method of the lead-out electrode.
<Embodiment 3>
(Configuration of resistive touch panel)
Next, the configuration of the resistive touch panel 5 according to the third embodiment of the present invention will be described focusing on differences from the second embodiment.

FIG. 16 is a cross-sectional view showing a configuration example of the inner type resistive touch panel 5 according to the third embodiment of the present invention and a configuration of the LCD combined therewith.
The touch panel 5 shown in FIG. 16 includes a polarizing plate 310 and a film laminate 500 (transparent resin film 511, transparent conductive film 13b, wiring substrate 510, spacer 516, transparent conductive film 23b, and transparent resin film 521) in order from the top. Laminated. Under the transparent resin film 521, an LCD main body 330 and a polarizing plate 320, which are constituent elements of the LCD panel, are laminated in the same order, and the entire LCD touch panel is configured.

The touch panel 5 employs a so-called “4-wire method” input detection method, and has a configuration called “FF inner type” using film materials for both of the transparent resin films 511 and 521. In this example, it is intended for use in an in-car car navigation system.
The polarizing plates 310 and 320 are each made of, for example, a dye-based linear polarizing plate having a thickness of 0.2 mm. One of the polarizing plates 310 is laminated on the surface of the transparent resin film 511 and exposed to the outside as a feature of the inner type touch panel. Thereby, the effect | action which suppresses the reflected light quantity resulting from the visible light which injects into the inside of a touch panel to about half or less compared with the case where the said polarizing plate is not provided is made | formed.

  330 directly laminated on the transparent resin film 521 is an LCD main body. This is a known TFT type LCD substrate, and constitutes a unit in which a transparent conductive layer (not shown), a color filter, a liquid crystal molecular layer, a TFT substrate, and a transparent conductive layer are laminated. The LCD body 330 may be other than the TFT type, and is not limited to the above laminated structure. The polarizing plate 320 is laminated under the LCD main body 20.

  The transparent conductive films 13b and 23b are uniformly formed with a predetermined area on the opposing surfaces of the transparent resin film 511 and the transparent resin film 521, respectively. At both ends of the transparent conductive film 13b (23b) on the x-axis side (y-axis side), drawers for connecting the transparent conductive films 13b and 23b and the wiring board 510 along the y-axis direction (x-axis direction) Electrodes (not shown) are formed. In the third embodiment, laser patterning is mainly used for the formation of extraction electrodes around the transparent conductive films 13b and 23b.

Each of the transparent conductive films 13b and 23b is disposed so as to face each other between the pair of transparent resin films 511 and 521 at a predetermined interval. An adhesive layer 518 is disposed around each of the transparent resin films 511 and 521. On the surface of one transparent resin film 521, a number of cone-shaped rib spacers 518 having a height of about 0.05 mm are provided.
The wiring substrate 510 is formed by forming a flexible substrate 301 made of a resin material such as PET or polyimide, and wirings 302 to 305 made of a material having good conductivity of Au, Ag, and Cu on the surface of the substrate. .

The principle of input detection on the touch panel 5 in which the electrical wiring is made with the above configuration (4wire method) is to apply a DC voltage of about 5V between the extraction electrodes along the y axis at the time of driving. When input is made, position data in the y-axis direction is acquired using the extraction electrode along the x-axis as a voltage detection electrode.
Next, voltage is applied between the extraction part electrodes along the x-axis, and the extraction data along the y-axis is used as a voltage detection electrode to acquire position data in the x-axis direction. Thereby, coordinate information of both xy is obtained. In the touch panel 5, such detection steps are alternately repeated, so that input information from the user is sequentially acquired and a function as a GUI is exhibited.

  In the touch panel 5 having the above configuration, the transparent conductive films 13b and 23b and the extraction electrode in the film laminate 500 are laser-patterned in the laminate structure. Therefore, in addition to the excellent visibility and manufacturing efficiency improvement effect as in the second embodiment, there is an advantage that the wiring structure around the touch panel can be made smaller and lighter by forming the lead electrode with a fine structure. .

(Other matters)
In the first embodiment, the configuration using the Nd: YAG laser is exemplified, but the present invention is not limited to this, and an Nd: YVO ₄ laser, an Nd: YLF laser, a Ti: sapphire laser, or the like is used. Can do.
Further, in the first embodiment, the method of ablating the transparent conductive film on the laser incident side from one main surface of the workpiece WP is exemplified, but the present invention is not limited to this, for example, both surfaces of the workpiece WP. The transparent conductive film adjacent to each laser incident side may be ablated in parallel by simultaneously irradiating each of the lasers. Employing such a method is preferable because a film laminate can be quickly completed by, for example, a roll-to-roll method and stored in a large amount.

  INDUSTRIAL APPLICABILITY The present invention is applied to, for example, a notebook computer, a mobile phone, a portable information terminal device, a car navigation system, or a display with a touch panel (liquid crystal display integrated touch panel device) that is expected to be used in high definition and a manufacturing method thereof. Is possible.

1 is a configuration diagram of a laser processing apparatus in Embodiment 1 of the present invention. FIG. It is a functional block diagram of a laser processing apparatus. It is a graph which shows the relationship between laser intensity distribution and a beam diameter. It is a graph which shows the relationship between film material and an absorptance. It is a graph which shows the transmittance | permeability characteristic of a resin film with a transparent conductive film. It is a schematic diagram which shows the mode of laser patterning. It is a fragmentary sectional view which shows the mode of the workpiece before and behind laser patterning. It is a graph which shows the relationship between pulse energy and processing width. It is a graph which shows the relationship between a process width and a heat influence width. It is a graph which shows the relationship between a beam diameter and a processing width. It is a graph which shows the relationship between a beam diameter and a processing width. It is a graph which shows the relationship between a beam diameter and a processing width. FIG. 5 is a configuration diagram of a capacitive touch panel according to Embodiment 2 of the present invention. It is a schematic diagram for demonstrating the input detection principle (capacitance type) of a capacitive touch panel. It is a figure which shows the mode of the patterning of a transparent electrode. FIG. 5 is a configuration diagram of a capacitive touch panel according to Embodiment 2 of the present invention.

Explanation of symbols

w _o Focus beam radius
w Machining width radius
1 Laser processing equipment (laser trimming equipment)
2 Laser irradiation system
4 Capacitive touch panel
5 Resistive touch panel
10 xy table
11 pedestal
12 Bridge section
12a1-12an, 22a1-22an line electrode
12b, 22b Transparent electrode group
13 y-axis table
14 x axis table
20 Laser beam irradiation equipment
100 machining head
201 Beam transmission system
211 Third harmonic generator
212 Athenata
213 Beam Expander
400, 500 film laminate
411 First resin film with transparent electrode
421 Resin film with second transparent electrode
411a, 421b Ruled part
443, 518 Adhesive layer

Claims (15)

A method of manufacturing a touch panel that undergoes a processing step of patterning a transparent electrode by scanning a transparent conductive film with a UV laser,
In the processing step,
For a workpiece comprising a transparent conductive film interposed in a transparent resin film, laser irradiation is performed on the transparent conductive film through the transparent resin film,
The focal beam radius in the transparent conductive film is adjusted to a condition range that is larger than the processing width radius,
A method for manufacturing a touch panel, comprising: adjusting a laser intensity for ablating a transparent conductive film portion corresponding to the processing width, and patterning with a processing width of 10 μm or less. A method of manufacturing a touch panel that undergoes a processing step of patterning a transparent electrode by scanning a transparent conductive film with a UV laser,
In the processing step,
For a workpiece comprising a transparent conductive film interposed in a transparent resin film, the transparent conductive film is irradiated with laser through the resin transparent resin film, and
When the beam width corresponding to an intensity level 0.65 to 0.7 times the peak intensity h in the laser intensity distribution represented by a Gaussian distribution is w ₁ and the beam width corresponding to an intensity level 0.35 to 0.4 times the peak intensity h is w ₂ A method for manufacturing a touch panel, comprising adjusting a processing width in a range of w _{1 to} w ₂ and ablating a corresponding transparent conductive film portion with a processing width of 10 μm or less. 3. The touch panel manufacturing method according to claim 1, wherein in the processing step, a size ratio between a focal beam radius and a processing width radius is adjusted by adjusting a focal length. 4. The touch panel manufacturing method according to claim 1, wherein in the processing step, the ratio w / wo of the processing width radius w and the focal beam radius wo is adjusted to be 0.7 or less. 5. The touch panel manufacturing method according to claim 1, wherein a UV laser having a wavelength of 320 nm to 450 nm is used as the UV laser in the processing step. 6. The touch panel manufacturing method according to claim 1, wherein a third harmonic YAG laser is used as the UV laser in the processing step. In the processing step, the patterning conditions are adjusted so that the ratio f ₁₂ / W of the laser focal length f ₁₂ of the processing lens optical system and the lens incident beam radius W in the laser irradiation apparatus is 40 or more and 98 or less. A method for manufacturing a touch panel according to any one of claims 1 to 6. In the processing step, as a transparent resin film that transmits laser, polyethylene terephthalate, polyimide, polyethylene naphthalate, polyethersulfone, polyetheretherketone, polycarbonate, polypropylene, polyamide, polyacryl, acrylic, amorphous polyolefin resin 8. The method for producing a touch panel according to claim 1, wherein at least one of cyclic polyolefin-based resin, aliphatic cyclic polyolefin, and norbornene-based thermoplastic transparent resin is used. In the processing step, as the transparent conductive film, antimony-added lead oxide, fluorine-added tin oxide, aluminum-added zinc oxide, potassium-added zinc oxide, silicon-added zinc oxide, zinc oxide-tin oxide system, indium tin oxide, indium tin oxide-oxidized 9. The touch panel manufacturing method according to claim 1, wherein at least one of tin, tin oxide film, copper, aluminum, nickel, and chromium is used. In the processing step, in the case where indium tin oxide is used as the transparent conductive film of the workpiece, and a polyethylene terephthalate film is used as the transparent resin film,
The ratio of the processing width radius w to the focal beam radius wo is set in the range of 1.5 to 2.3, the processing width is adjusted to 5 μm to 10 μm, and the laser energy per pulse applied to the transparent conductive film is 0.2 μJ / 10. The method for manufacturing a touch panel according to claim 1, wherein the range is set to a range of not less than pulses and not more than 1.4 μJ / pulse. 11. The workpiece according to any one of claims 1 to 10, wherein a workpiece is a laminate of a pair of resin films with a transparent conductive film interposed via an insulating layer so that the transparent conductive films face each other. A method for manufacturing a touch panel. 12. The method for manufacturing a touch panel according to claim 11, wherein an adhesive layer is used as the insulating layer. A film laminate for a touch panel, in which a pair of transparent electrode-attached resin films are laminated so that the transparent electrodes on each film are opposed to each other at a predetermined interval,
13. The touch panel film laminate, wherein at least one of the pair of transparent electrode-attached resin films is obtained by patterning the transparent conductive film by the processing step according to claim 1. A capacitive touch panel using a resin film with a transparent conductive film, in which a transparent electrode is disposed on the main surface of the transparent resin film,
13. The capacitive touch panel, wherein the transparent electrode-attached resin film is obtained by patterning the transparent conductive film by the processing step according to any one of claims 1 to 12. A capacitive touch panel comprising a film laminate in which a plurality of transparent electrodes are respectively disposed on both main surfaces of an insulating layer,
13. The capacitive touch panel according to claim 1, wherein the transparent electrode on at least one of the main surfaces of the insulating layer is patterned by the processing step according to any one of claims 1 to 12.

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